Patent Publication Number: US-2022233263-A1

Title: Systems, apparatus and methods for robotic interventional procedures using a plurality of elongated medical devices

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on, claims priority to, and incorporates herein by reference in its entirety U.S. Ser. No. 62/874,247, filed Jul. 15, 2019, and entitled “Systems, Apparatus and Methods for Robotic Interventional Procedures Using a Plurality of Elongated Medical Devices.” 
    
    
     FIELD 
     The present invention relates generally to the field of robotic medical procedure systems and, in particular, to systems, apparatus and methods for robotically controlling the movement and operation of elongated medical devices in robotic interventional procedures. 
     BACKGROUND 
     Catheters and other elongated medical devices (EMDs) may be used for minimally invasive medical procedures for the diagnosis and treatment of diseases of various vascular systems, including neurovascular intervention (NVI) also known as neurointerventional surgery, percutaneous coronary intervention (PCI) and peripheral vascular intervention (PVI). These procedures typically involve navigating a guidewire through the vasculature, and via the guidewire advancing a catheter to deliver therapy. The catheterization procedure starts by gaining access into the appropriate vessel, such as an artery or vein, with an introducer sheath using standard percutaneous techniques. Through the introducer sheath, a sheath or guide catheter is then advanced over a diagnostic guidewire to a primary location such as an internal carotid artery for NVI, a coronary ostium for PCI, or a superficial femoral artery for PVI. A guidewire suitable for the vasculature is then navigated through the sheath or guide catheter to a target location in the vasculature. In certain situations, such as in tortuous anatomy, a support catheter or microcatheter is inserted over the guidewire to assist in navigating the guidewire. The physician or operator may use an imaging system (e.g., fluoroscope) to obtain a cine with a contrast injection and select a fixed frame for use as a roadmap to navigate the guidewire or catheter to the target location, for example, a lesion. Contrast-enhanced images are also obtained while the physician delivers the guidewire or catheter so that the physician can verify that the device is moving along the correct path to the target location. While observing the anatomy using fluoroscopy, the physician manipulates the proximal end of the guidewire or catheter to direct the distal tip into the appropriate vessels toward the lesion or target anatomical location and avoid advancing into side branches. 
     Robotic catheter-based procedure systems have been developed that may be used to aid a physician in performing catheterization procedures such as, for example, NVI, PCI and PVI. Examples of NVI procedures include coil embolization of aneurysms, liquid embolization of arteriovenous malformations and mechanical thrombectomy of large vessel occlusions in the setting of acute ischemic stroke. In an NVI procedure, the physician uses a robotic system to gain target lesion access by controlling the manipulation of a neurovascular guidewire and microcatheter to deliver the therapy to restore normal blood flow. Target access is enabled by the sheath or guide catheter but may also require an intermediate catheter for more distal territory or to provide adequate support for the microcatheter and guidewire. The distal tip of a guidewire is navigated into, or past, the lesion depending on the type of lesion and treatment. For treating aneurysms, the microcatheter is advanced into the lesion and the guidewire is removed and several embolization coils are deployed into the aneurysm through the microcatheter and used to block blood flow into the aneurysm. For treating arteriovenous malformations, a liquid embolic is injected into the malformation via a microcatheter. Mechanical thrombectomy to treat vessel occlusions can be achieved either through aspiration and/or use of a stent retriever. Depending on the location of the clot, aspiration is either done through an aspiration catheter, or through a microcatheter for smaller arteries. Once the aspiration catheter is at the lesion, negative pressure is applied to remove the clot through the catheter. Alternatively, the clot can be removed by deploying a stent retriever through the microcatheter. Once the clot has integrated into the stent retriever, the clot is retrieved by retracting the stent retriever and microcatheter (or intermediate catheter) into the guide catheter. 
     In PCI, the physician uses a robotic system to gain lesion access by manipulating a coronary guidewire to deliver the therapy and restore normal blood flow. The access is enabled by seating a guide catheter in a coronary ostium. The distal tip of the guidewire is navigated past the lesion and, for complex anatomies, a microcatheter may be used to provide adequate support for the guidewire. The blood flow is restored by delivering and deploying a stent or balloon at the lesion. The lesion may need preparation prior to stenting, by either delivering a balloon for pre-dilation of the lesion, or by performing atherectomy using, for example, a laser or rotational atherectomy catheter and a balloon over the guidewire. Diagnostic imaging and physiological measurements may be performed to determine appropriate therapy by using imaging catheters or fractional flow reserve (FFR) measurements. 
     In PVI, the physician uses a robotic system to deliver the therapy and restore blood flow with techniques similar to NVI. The distal tip of the guidewire is navigated past the lesion and a microcatheter may be used to provide adequate support for the guidewire for complex anatomies. The blood flow is restored by delivering and deploying a stent or balloon to the lesion. As with PCI, lesion preparation and diagnostic imaging may be used as well. 
     When support at the distal end of a catheter or guidewire is needed, for example, to navigate tortuous or calcified vasculature, to reach distal anatomical locations, or to cross hard lesions, an over-the-wire (OTW) catheter or coaxial system is used. An OTW catheter has a lumen for the guidewire that extends the full length of the catheter. This provides a relatively stable system because the guidewire is supported along the whole length. This system, however, has some disadvantages, including higher friction, and longer overall length compared to rapid-exchange catheters (see below). Typically to remove or exchange an OTW catheter while maintaining the position of the indwelling guidewire, the exposed length (outside of the patient) of guidewire must be longer than the OTW catheter. A 300 cm long guidewire is typically sufficient for this purpose and is often referred to as an exchange length guidewire. Due to the length of the guidewire, two operators are needed to remove or exchange an OTW catheter. This becomes even more challenging if a triple coaxial, known in the art as a tri-axial system, is used (quadruple coaxial catheters have also been known to be used). However, due to its stability, an OTW system is often used in NVI and PVI procedures. On the other hand, PCI procedures often use rapid exchange (or monorail) catheters. The guidewire lumen in a rapid exchange catheter runs only through a distal section of the catheter, called the monorail or rapid exchange (RX) section. With a RX system, the operator manipulates the interventional devices parallel to each other (as opposed to with an OTW system, in which the devices are manipulated in a serial configuration), and the exposed length of guidewire only needs to be slightly longer than the RX section of the catheter. A rapid exchange length guidewire is typically 180-200 cm long. Given the shorter length guidewire and monorail, RX catheters can be exchanged by a single operator. However, RX catheters are often inadequate when more distal support is needed. 
     SUMMARY 
     In accordance with an embodiment, a robotic drive system for driving one or more elongated medical devices includes a linear member and at least four device modules coupled to the linear member. Each device module may be independently controllable. The plurality of device modules may be switched between a first configuration where each device module is populated with an elongated medical device and a second configuration where a subset of the at least four device modules is populated with an elongated medical device. 
     In accordance with another embodiment, a robotic drive system for driving one or more elongated medical devices includes a linear member and a plurality of device modules movably coupled to the linear member. Each drive module is configured to manipulate an elongated medical device and each device module may be independently controllable; The plurality of device modules may be switched between a first configuration including at least one device module configured to drive a proximal region of the corresponding elongated medical device along a first longitudinal axis and a second configuration including at least one device module configured to drive a proximal portion of the corresponding elongated medical device along a second longitudinal axis different from the first longitudinal axis. 
     In accordance with another embodiment, a robotic drive system for driving one or more elongated medical devices includes a linear member and at least four device modules coupled to the linear member. Each device module is configured to manipulate an elongated medical device and each device module may be independently controllable. The plurality of device modules may be switched between a triaxial configuration and a biaxial configuration. In the triaxial configuration, the elongated medical device manipulated by three of the at least four device modules is a catheter and the elongated medical device manipulated by a fourth device module of the at least four device modules is a wire-based device. In the biaxial configuration, the elongated medical device manipulated by two of the at least four device modules is a catheter, the elongated medical device manipulated by a third device module of the at least four device modules is a wire-based device and a fourth device module of the at least four device modules is unpopulated. 
     In accordance with another embodiment, a robotic drive system for driving one or more elongated medical devices includes a linear member, a first device module coupled to the linear member and a second device module coupled to the linear member at a position distal to the first device module. The first device module is configured to manipulate a first elongated medical device and may be independently controllable. The second device module is configured to manipulate a second elongated medical device and may be independently controllable. The robotic drive system further includes a device support having a section moveably positioned in the first device module and having a first end and a second end. The device support is configured to provide a channel to contain and support the first elongated medical device in a distance between the first device module and the second device module. The first end and the second end of the device support are coupled to the second device module. 
     In accordance with another embodiment, a robotic drive system for driving one or more elongated medical devices includes a linear member, a device module coupled to the linear member and a distal support arm having a device support connection located distal to the device module. The device module is configured to manipulate an elongated medical device and may be independently controllable. The robotic drive system further includes a device support moveably positioned in the device module and having a first end and a second end. The device support is configured to provide a channel to contain and support an elongated medical device in a distance between the device module and the device support connection. The first end and the second end of the device support are coupled to the distal support arm. 
     In accordance with another embodiment, a robotic drive system for driving one or more elongated medical devices includes a linear member; a first drive module coupled to the linear member, a cassette mounted to the first drive module and having a proximal end, and a second drive module coupled to the linear member at a position proximal to the first drive module. The second drive module is configured to be positioned in an area of overlap with the proximal end of the cassette mounted to the first drive module. 
     In accordance with an embodiment, a robotic drive system for driving one or more elongated medical devices includes a linear member, a first device module coupled to the linear member, a second device module coupled to the linear member, and a deployable elongated medical device having a first section and a second section. The first section is positioned on the first device module and the second section is positioned on the second device module. The first device module and the second device module may be independently controllable. An independent linear motion of the second device module along the rail may be used to actuate the second section of the deployable elongated medical device. 
     In accordance with another embodiment, a method for loading an elongated medical device to a device module in a robotic drive system having a plurality of device modules and configured for driving a plurality of elongated medical devices includes moving, using the robotic drive, a proximal device module to a position that is a predetermined distance from a distal device module that includes a distal elongated medical device having a hub, receiving a first end of a proximal elongated medical device in the hub of the distal elongated medical device and receiving the proximal elongated medical device in the proximal device module. The predetermined distance is determined based on a desired gap between a first end of the distal elongated medical device and the first end of the proximal elongated medical device when the proximal elongated medical device is being received in the proximal device module, a length of the distal elongated medical device and a length of the proximal elongated medical device. 
     In accordance with another embodiment, a robotic drive system for driving one or more elongated medical devices includes a linear member and a plurality of device modules coupled to the linear member. The plurality of device modules are configured to allow a prepared subassembly of a plurality of elongated medical devices to be side-loaded into the plurality of device modules. Each of the plurality of device modules receives one of the plurality of elongated medical devices. 
     In accordance with another embodiment a robotic drive system for driving one or more elongated medical devices includes a linear member having a length, a first device module configured to manipulate a first elongated medical device, a first stage coupled to the linear member and a first offset bracket connected between the first device module and the first stage to couple the first device module to the first stage. The first device module may be independently controllable and has a center point. The first stage has a center point. The first offset bracket defines a first offset distance between the center point of the first device module and the center point of the first stage. The system further includes a second device module configured to manipulate a second elongated medical device, a second stage coupled to the linear member, and a second offset bracket connected between the second device module and the second stage to couple the second device module to the second stage. The second device module may be independently controllable and has a center point. The second stage has a center point. The second offset bracket defines a second offset distance between the center point of the second device module and the center point of the second stage. A range of linear motion of the first device module along the linear member and a range of linear motion of the second device module along the linear member overlap. The range of linear motion of the first device module extends beyond the length of the linear member in a distal direction. 
     In accordance with another embodiment, a robotic drive system for driving one or more elongated medical devices includes a linear member having a length, a first device module configured to manipulate a first elongated medical device, a first stage coupled to the linear member and a first offset bracket connected between the first device module and the first stage to couple the first device module to the first stage. The first device module may be independently controllable and has a center point. The first stage has a center point. The first offset bracket defines a first offset distance between the center point of the first device module and the center point of the first stage. The system further includes a second device module configured to manipulate a second elongated medical device, a second stage coupled to the linear member, and a second offset bracket connected between the second device module and the second stage to couple the second device module to the second stage. The second device module may be independently controllable and has a center point. The second stage has a center point. The second offset bracket defines a second offset distance between the center point of the second device module and the center point of the second stage. The first offset distance and the second offset distance are configured to minimize the length of the linear member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will become more fully understood from the following detailed description, taken in conjunction with the accompanying drawings, wherein the reference numerals refer to like parts in which: 
         FIG. 1  is a perspective view of an exemplary catheter-based procedure system in accordance with an embodiment; 
         FIG. 2  is a schematic block diagram of an exemplary catheter-based procedure system in accordance with an embodiment; 
         FIG. 3  is a perspective view of a robotic drive for a catheter-based procedure system in accordance with an embodiment; 
         FIG. 4  is a perspective view of a portion of robotic drive for a catheter-based procedure system in accordance with an embodiment; 
         FIG. 5  is a perspective view of a drive module attached to a stage in accordance with an embodiment; 
         FIG. 6  is a side cross-sectional view of a drive module in accordance with an embodiment; 
         FIG. 7  is a perspective view of an exemplary cassette in accordance with an embodiment; 
         FIG. 8  is a top view of an exemplary cassette attached to a drive module in accordance with an embodiment; 
         FIG. 9  is a top view of an exemplary cassette attached to a drive module which is connected to a stage in accordance with an embodiment; 
         FIG. 10  is a diagram illustrating an elongated medical device axis of manipulation and the introductory point into the patient; 
         FIGS. 11 a  and 11 b    are diagrams illustrating the effect of the thickness of a robotic drive on the loss of working length; 
         FIG. 12  is a diagram illustrating an exemplary orientation to minimize loss of working length; 
         FIG. 13  is a perspective view of a device module with a horizontally mounted cassette in accordance with an embodiment; 
         FIG. 14  is a rear perspective view of a device module with a horizontally mounted cassette in accordance with an embodiment; 
         FIG. 15  is a front view of a distal end of a device module with a horizontally mounted cassette in accordance with an embodiment; 
         FIG. 16  is a front view of a distal end of a device module with a vertically mounted cassette in accordance with an embodiment; 
         FIG. 17  is a block diagram illustrating an occupied length on a linear member without offsets between device modules and stages in accordance with an embodiment; 
         FIG. 18A  is a block diagram illustrating occupied length on a linear member with offsets between device modules and stages in accordance with an embodiment; 
         FIG. 18B  is a block diagram illustrating an example offset bracket configuration in accordance with an embodiment; 
         FIG. 18C  is a block diagram illustrating an example offset bracket configuration in accordance with an embodiment; 
         FIG. 19  is a side view of a robotic drive with offset brackets in accordance with an embodiment; 
         FIG. 20  is an isometric view of a robotic drive with offset brackets in accordance with an embodiment; 
         FIG. 21  is a top view of a robotic drive with offset brackets in accordance with an embodiment; 
         FIG. 22  is a top view of a portion of a robotic drive configured to drive four elongated medical devices in accordance with an embodiment; 
         FIG. 23  is a perspective view of a catheter with an on-device adapter in accordance with an embodiment; 
         FIG. 24  is a perspective view of a guidewire with an on-device adapter in accordance with an embodiment; 
         FIG. 25  is a perspective view of a cassette with an installed elongated medical device with an on-device adapter in accordance with an embodiment; 
         FIG. 26  is a exploded view of a cassette and an elongated medical device with an on-device adapter that is removed from the cassette in accordance with an embodiment; 
         FIG. 27  is a top view of a portion of a robotic drive configured to drive three elongated medical devices in accordance with an embodiment; 
         FIG. 28A  is a diagram of a first device module mechanically coupled to a second device module to share linear movement of the first device module in accordance with an embodiment; 
         FIG. 28B  is a diagram of an exemplary mechanical mount for a device module in accordance with an embodiment; 
         FIG. 29  is a block diagram illustrating changing a position of a device module in a robotic drive where the device module is mechanically coupled to another device module in accordance with an embodiment; 
         FIG. 30  is a block diagram illustrating different positions for a device module in a robotic drive where the device module is mechanically coupled to another device module in accordance with an embodiment; 
         FIG. 31  is a block diagram illustrating changing the position of a device module in a robotic drive where the device module is configured to be populated with more than one elongated medical device in accordance with an embodiment; 
         FIG. 32  is a block diagram of a robotic drive including three device modules and a nested unpopulated drive module in accordance with an embodiment; 
         FIG. 33  is a block diagram of a robotic drive including two device modules and two nested unpopulated drive modules in accordance with an embodiment; 
         FIG. 34  is a side view of three unpopulated drive modules and offset brackets in accordance with an embodiment; 
         FIG. 35  is a side rear view of three unpopulated drive modules and offset brackets in accordance with an embodiment; 
         FIG. 36  is a side view of two nested unpopulated drive modules and two device modules in accordance with an embodiment; 
         FIG. 37  is an isometric view of a robotic drive with two nested unpopulated drive modules and two device modules in accordance with an embodiment; 
         FIG. 38  is a block diagram illustrating a cassette crash prevention apparatus and method in accordance with an embodiment; 
         FIG. 39  is a block diagram illustrating an unpopulated drive module crash prevention apparatus and method in accordance with an embodiment; 
         FIG. 40  is a front view of a robotic drive with a linear member having two slides in accordance with an embodiment; 
         FIG. 41  is a perspective view of the robotic drive of  FIG. 40  in accordance with an embodiment; 
         FIGS. 42A-42D  illustrate a translating device module that may be repositioned along a linear member in a robotic drive in accordance with an embodiment; 
         FIG. 43  is a top view of a portion of robotic drive in a tri-axial configuration and including drive modules with more than one coupler in accordance with an embodiment; 
         FIG. 44  is a top view of a portion of a robotic drive in a bi-axial configuration and including drive modules with more than one coupler in accordance with an embodiment; 
         FIG. 45  is a top view of a portion of a robotic drive in a mono-axial configuration and including drive modules with more than one coupler in accordance with an embodiment; 
         FIG. 46  is a side view of a cassette with one degree of freedom mounted to a drive module with more than one coupler in accordance with an embodiment; 
         FIG. 47  is a top view of a portion of a robotic drive in a tri-axial configuration and including both drive modules with a single coupler and drive modules with more than one coupler in accordance with an embodiment; 
         FIG. 48  is a top view of a portion of a robotic drive in a bi-axial configuration and includes a cassette mounted to two drive modules in accordance with an embodiment; 
         FIG. 49  is a top view of a portion of a robotic drive in mono-axial configuration and includes a cassette mounted to two drive modules in accordance with an embodiment; 
         FIG. 50  is a block diagram of a parallel configuration for elongated medical devices in a robotic drive in accordance with an embodiment; 
         FIG. 51  is a top view of a cassette with a bypass channel and elongated medical devices in a serial configuration in accordance with an embodiment; 
         FIG. 52  is a top view of a cassette with a bypass channel and elongated medical devices in a parallel configuration in accordance with an embodiment; 
         FIG. 53  is a block diagram of a parallel configuration for elongated medical devices in a robotic drive in accordance with an embodiment; 
         FIG. 54  is a top view of a cassette configured to receive two elongated medical devices in a parallel configuration in accordance with an embodiment; 
         FIG. 55  is a block diagram of a robotic drive configuration with multiple device axes in accordance with an embodiment; 
         FIG. 56  is a block diagram of an elongated medical device positioned across two device modules in a first position in accordance with an embodiment; 
         FIG. 57  is a top view of an elongated medical device positioned across two device modules in a second position in accordance with an embodiment; 
         FIG. 58  is a top view of an elongated medical device positioned across two device modules in a third position in accordance with an embodiment; 
         FIG. 59  is a perspective view of an exemplary rotationally deployable elongated medical device with an on-device adapter in accordance with an embodiment; 
         FIG. 60  is cross-sectional view of the rotationally deployable EMD of  FIG. 59  in an un-deployed state in accordance with an embodiment; 
         FIG. 61  is cross-sectional view of the rotationally deployable EMD of  FIG. 59  in a deployed state in accordance with an embodiment; 
         FIG. 62  is a cross-sectional vie of the rotationally deployable EMD of  FIG. 59  in a cassette on a drive module in accordance with an embodiment; 
         FIG. 63  is a block diagram of a parallel device configuration using a global parking clamp in accordance with an embodiment; 
         FIG. 64  is a perspective view of a moveable global parking clamp in accordance with an embodiment; 
         FIG. 65  is top view of a device module including a cassette with a module parking clamp in accordance with embodiment; 
         FIG. 66  is a top view of a device module including a cassette with a rapid exchange tire drive in accordance with an embodiment; 
         FIG. 67  is a perspective view of a drive mechanism and interface between a drive module and the rapid exchange tire drive in accordance with an embodiment; 
         FIG. 68  is a perspective view of an drive mechanism and interface between a drive module and the rapid exchange tire drive in accordance with an embodiment; 
         FIG. 69  is an exemplary robotic drive device module configuration including a rapid exchange tire drive in accordance with an embodiment; 
         FIG. 70  is a block diagram of a robotic drive configuration including a dedicated guidewire and rapid exchange catheter device module in accordance with an embodiment; 
         FIG. 71  is a top view of a robotic drive with multiple parallel linear members in accordance with embodiment; 
         FIG. 72  is a sectioned view of a device module with a position offset slide and the device module in a first position in accordance with an embodiment; 
         FIG. 73  is a sectioned view of a device module with a position offset slide and the device module in a second position in accordance with an embodiment; 
         FIG. 74  is a top view of device modules in an exemplary serial configuration in a multiple linear member robotic drive in accordance with an embodiment; 
         FIG. 75  is a perspective view of device modules in an exemplary serial configuration in a multiple linear member robotic drive in accordance with an embodiment; 
         FIG. 76  is a top view of device modules in an exemplary parallel configuration in a multiple linear member robotic drive in accordance with an embodiment; 
         FIG. 77  is a perspective view of device modules in an exemplary parallel configuration in a multiple linear member robotic drive in accordance with an embodiment; 
         FIGS. 78A-C  illustrate reconfiguring device module positions using a positioning system in accordance with an embodiment; 
         FIG. 79  is a perspective view of device supports with fixed front (or distal) and rear (or proximal) points to provide tension in accordance with an embodiment; 
         FIG. 80  is a diagram showing a top view of a cassette with a device support in a withdrawn position to facilitate exchange of an elongated medical device in accordance with an embodiment; 
         FIG. 81  is a diagram showing a top view of a cassette with a device support in an extended position constrained at two ends in accordance with an embodiment; 
         FIG. 82  is a top view of two device modules with device supports in accordance with an embodiment; 
         FIG. 83  is a top view illustrating forward translation of a device module linearly relative to a device support in accordance with an embodiment; 
         FIG. 84  is a top view illustrating reverse translation of a device module linearly relative to a device support in accordance with an embodiment; 
         FIG. 85  is a top view illustrating reverse translation of a device support linearly relative to a device module in accordance with an embodiment; 
         FIG. 86  shows a simplified top view of four device modules and four device supports for a robotic drive in accordance with an embodiment; 
         FIG. 87  shows a simplified top view illustrating movement of a device module relative to a device support in accordance with an embodiment; 
         FIG. 88  shows a simplified top view illustrating the four device modules of  FIG. 86  in a forward position relative to their respective device support in accordance with an embodiment; 
         FIG. 89  shows a simplified top view illustrating the four device modules of  FIG. 86  in a withdrawn position relative to their respective device support in accordance with an embodiment; 
         FIG. 90  is a side view of a proximal end of a device support that is extended and a rear constraint for a rear fixed point to which the device support is connected in accordance with an embodiment; 
         FIG. 91  is a side view of a proximal end of a device support that is partially retracted and a rear constraint for a rear fixed point to which the device support is connected in accordance with an embodiment; 
         FIG. 92  shows a simplified top view of device modules with device supports stored on a reel in accordance with an embodiment; 
         FIG. 93  shows an exemplary spooled tensioner in accordance with an embodiment; 
         FIG. 94  shows a simplified top view of device modules with drive device supports in accordance with an embodiment; 
         FIG. 95  shows an exemplary geared tensioner in accordance with an embodiment; 
         FIG. 96  shows a simplified top view of device modules with device supports formed with accordions or springs in accordance with an embodiment; 
         FIG. 97  illustrates a compressed accordion/spring in accordance with an embodiment; 
         FIG. 98  illustrates a stretched accordion/spring in accordance with an embodiment; 
         FIG. 99A-C  are perspective views of exemplary slit shapes for a device support flexible tube in accordance with an embodiment; 
         FIG. 100  is an exploded view of a device module and an elongated medical device in accordance with an embodiment; 
         FIG. 101A  is a perspective view of a cassette with a device support installed and in a retracted position in accordance with an embodiment; 
         FIG. 101B  is a perspective view of a cassette with a device support installed in accordance with an embodiment; 
         FIG. 102  is a top view of a device support and connector extended from a cassette ahead of an EMD entry point in accordance with an embodiment; 
         FIG. 103  is a top view of a device support and connector withdrawn behind an EMD entry point in accordance with an embodiment; 
         FIG. 104  is an end view of a splitter holding open a device support in accordance with an embodiment; 
         FIG. 105  is a top view of cassette with a device support connector withdrawn and off of a device axis to facilitate loading of an EMD in accordance with an embodiment; 
         FIG. 106  is a perspective view of a forward constraint and a connector in accordance with an embodiment; 
         FIG. 107  is a perspective view of a forward constraint with a lid in accordance with an embodiment; 
         FIG. 108  is a perspective view of a distal support arm and distal support connection in accordance with an embodiment; 
         FIG. 109  is a perspective view of a distal support connection coupled to a device support and connector in accordance with an embodiment; 
         FIG. 110  is a side view of a distal support arm, distal support connection and an introducer interface support in accordance with an embodiment; 
         FIG. 111  is a perspective view of an introducer interface support connected to an introducer sheath in accordance with an embodiment; 
         FIG. 112  is a perspective view of a movable distal support arm in a first position in accordance with an embodiment; 
         FIG. 113  is a perspective view of a moveable distal support arm in a second position in accordance with an embodiment; 
         FIG. 114  is a top view of a moveable distal support arm and movable support arm in a first position in accordance with an embodiment; 
         FIG. 115   40  is a top view of a moveable distal support arm and movable support arm in a second position in accordance with an embodiment; 
         FIG. 116  is a top view illustrating movement of a distal support arm and a support arm from the second position to the first position in accordance with an embodiment; 
         FIG. 117  is a block diagram illustrating a method for loading or unloading an EMD in a robotic drive with a safe loading distance in accordance with an embodiment; 
         FIG. 118  is a top view of device modules of a robotic drive in a loading position in accordance with an embodiment; 
         FIG. 119  is a top view of the device modules of  FIG. 118  in a loading position and a set of prepared EMDs in accordance with an embodiment; and 
         FIG. 120  is a top view of the set of prepared EMDs of  FIG. 119  loaded into the appropriate device modules in accordance with an embodiment; 
         FIG. 121  is a schematic diagram of an elongated medical device, a gapping tool and an on-device adapter in accordance with an embodiment; 
         FIG. 122  is a schematic diagram of an elongated medical device, a gapping tool and an on-device adapter in accordance with an embodiment; 
         FIG. 123  is a diagram of an example gapping tool in accordance with an embodiment; and 
         FIG. 124  is a diagram of an example gapping tool in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The following definitions will be used herein. The term elongated medical device (EMD) refers to, but is not limited to, catheters (e.g. guide catheters, microcatheters, balloon/stent catheters), wire-based devices (guidewires, embolization coils, stent retrievers, etc.), and devices that have a combination of these. Wire-based EMD includes, but is not limited to, guidewires, microwires, a proximal pusher for embolization coils, stent retrievers, self-expanding stents, and flow divertors. Typically wire-based EMD&#39;s do not have a hub or handle at its proximal terminal end. In one embodiment the EMD is a catheter having a hub at a proximal end of the catheter and a flexible shaft extending from the hub toward the distal end of the catheter, wherein the shaft is more flexible than the hub. In one embodiment the catheter includes an intermediary portion that transitions between the hub and the shaft that has an intermediate flexibility that is less rigid than the hub and more rigid than the shaft. In one embodiment the intermediary portion is a strain relief. 
     The terms distal and proximal define relative locations of two different features. With respect to a robotic drive the terms distal and proximal are defined by the position of the robotic drive in its intended use relative to a patient. When used to define a relative position, the distal feature is the feature of the robotic drive that is closer to the patient than a proximal feature when the robotic drive is in its intended in-use position. Within a patient, any vasculature landmark further away along the path from the access point is considered more distal than a landmark closer to the access point, where the access point is the point at which the EMD enters the patient. Similarly, the proximal feature is the feature that is farther from the patient than the distal feature when the robotic drive in its intended in-use position. When used to define direction, the distal direction refers to a path on which something is moving or is aimed to move or along which something is pointing or facing from a proximal feature toward a distal feature and/or patient when the robotic drive is in its intended in-use position. The proximal direction is the opposite direction of the distal direction. 
     The term longitudinal axis of a member (e.g., an EMD or other element in the catheter-based procedure system) is the direction of orientation going from a proximal portion of the member to a distal portion of the member. By way of example, the longitudinal axis of a guidewire is the direction of orientation from a proximal portion of the guide wire toward a distal portion of the guidewire even though the guidewire may be non-linear in the relevant portion. The term axial movement of a member refers to translation of the member along the longitudinal axis of the member. When a distal end of an EMD is axially moved in a distal direction along its longitudinal axis into or further into the patient, the EMD is being advanced. When the distal end of an EMD is axially moved in a proximal direction along its longitudinal axis out of or further out of the patient, the EMD is being withdrawn. The term rotational movement of a member refers to change in angular orientation of the member about the local longitudinal axis of the member. Rotational movement of an EMD corresponds to clockwise or counterclockwise rotation of the EMD about its longitudinal axis due to an applied torque. 
     The term axial insertion refers to inserting a first member into a second member along the longitudinal axes of the second member. The term lateral insertion refers to inserting a first member into a second member along a direction in a plane perpendicular to the longitudinal axis of the second member. This can also be referred to as radial loading or side loading. The term pinch refers to releasably fixing an EMD to a member such that the EMD and member move together when the member moves. The term unpinch refers to releasing the EMD from a member such that the EMD and member move independently when the member moves. The term clamp refers to releasably fixing an EMD to a member such that the EMD&#39;s movement is constrained with respect to the member. The member can be fixed with respect to a global coordinate system or with respect to a local coordinate system. The term unclamp refers to releasing the EMD from the member such that the EMD can move independently. 
     The term grip refers to the application of a force or torque to an EMD by a drive mechanism that causes motion of the EMD without slip in at least one degree of freedom. The term ungrip refers to the release of the application of force or torque to the EMD by a drive mechanism such that the position of the EMD is no longer constrained. In one example, an EMD gripped between two tires will rotate about its longitudinal axis when the tires move longitudinally relative to one another. The rotational movement of the EMD is different than the movement of the two tires. The position of an EMD that is gripped is constrained by the drive mechanism. The term buckling refers to the tendency of a flexible EMD when under axial compression to bend away from the longitudinal axis or intended path along which it is being advanced. In one embodiment axial compression occurs in response to resistance from being navigated in the vasculature. The distance an EMD may be driven along its longitudinal axis without support before the EMD buckles is referred to herein as the device buckling distance. The device buckling distance is a function of the device&#39;s stiffness, geometry (including but not limited to diameter), and force being applied to the EMD. Buckling may cause the EMD to form an arcuate portion different than the intended path. Kinking is a case of buckling in which deformation of the EMD is non-elastic resulting in a permanent set. 
     The terms top, up, and upper refer to the general direction away from the direction of gravity and the terms bottom, down, and lower refer to the general direction in the direction of gravity. The term inwardly refers to the inner portion of a feature. The term outwardly refers to the outer portion of a feature. The term sterile interface refers to an interface or boundary between a sterile and non-sterile unit. For example, a cassette may be a sterile interface between the robotic drive and at least one EMD. The term sterilizable unit refers to an apparatus that is capable of being sterilized (free from pathogenic microorganisms). This includes, but is not limited to, a cassette, consumable unit, drape, device adapter, and sterilizable drive modules/units (which may include electromechanical components). Sterilizable Units may come into contact with the patient, other sterile devices, or anything else placed within the sterile field of a medical procedure. 
     The term on-device adapter refers to sterile apparatus capable of releasably pinching an MED to provide a driving interface. For example, the on-device adapter is also known as an end-effector or EMD capturing device. In one non-limiting embodiment, the on-device adapter is a collet that is operatively controlled robotically to rotate the EMD about its longitudinal axis, to pinch and/or unpinch the EMD to the collet, and/or to translate the EMD along its longitudinal axis. In one embodiment the on-device adapter is a hub-drive mechanism such as a driven gear located on the hub of an EMD. 
       FIG. 1  is a perspective view of an exemplary catheter-based procedure system  10  in accordance with an embodiment. Catheter-based procedure system  10  may be used to perform catheter-based medical procedures, e.g., percutaneous intervention procedures such as a percutaneous coronary intervention (PCI) (e.g., to treat STEMI), a neurovascular interventional procedure (NVI) (e.g., to treat an emergent large vessel occlusion (ELVO)), peripheral vascular intervention procedures (PVI) (e.g., for critical limb ischemia (CLI), etc.). Catheter-based medical procedures may include diagnostic catheterization procedures during which one or more catheters or other elongated medical devices (EMDs) are used to aid in the diagnosis of a patient&#39;s disease. For example, during one embodiment of a catheter-based diagnostic procedure, a contrast media is injected onto one or more arteries through a catheter and an image of the patient&#39;s vasculature is taken. Catheter-based medical procedures may also include catheter-based therapeutic procedures (e.g., angioplasty, stent placement, treatment of peripheral vascular disease, clot removal, arterial venous malformation therapy, treatment of aneurysm, etc.) during which a catheter (or other EMD) is used to treat a disease. Therapeutic procedures may be enhanced by the inclusion of adjunct devices  54  (shown in  FIG. 2 ) such as, for example, intravascular ultrasound (IVUS), optical coherence tomography (OCT), fractional flow reserve (FFR), etc. It should be noted, however, that one skilled in the art would recognize that certain specific percutaneous intervention devices or components (e.g., type of guidewire, type of catheter, etc.) may be selected based on the type of procedure that is to be performed. Catheter-based procedure system  10  can perform any number of catheter-based medical procedures with minor adjustments to accommodate the specific percutaneous intervention devices to be used in the procedure. 
     Catheter-based procedure system  10  includes, among other elements, a bedside unit  20  and a control station  26 . Bedside unit  20  includes a robotic drive  24  and a positioning system  22  that are located adjacent to a patient  12 . Patient  12  is supported on a patient table  18 . The positioning system  22  is used to position and support the robotic drive  24 . The positioning system  22  may be, for example, a robotic arm, an articulated arm, a holder, etc. The positioning system  22  may be attached at one end to, for example, a rail on the patient table  18 , a base, or a cart. The other end of the positioning system  22  is attached to the robotic drive  24 . The positioning system  22  may be moved out of the way (along with the robotic drive  24 ) to allow for the patient  12  to be placed on the patient table  18 . Once the patient  12  is positioned on the patient table  18 , the positioning system  22  may be used to situate or position the robotic drive  24  relative to the patient  12  for the procedure. In an embodiment, patient table  18  is operably supported by a pedestal  17 , which is secured to the floor and/or earth. Patient table  18  is able to move with multiple degrees of freedom, for example, roll, pitch, and yaw, relative to the pedestal  17 . Bedside unit  20  may also include controls and displays  46  (shown in  FIG. 2 ). For example, controls and displays may be located on a housing of the robotic drive  24 . 
     Generally, the robotic drive  24  may be equipped with the appropriate percutaneous interventional devices and accessories  48  (shown in  FIG. 2 ) (e.g., guidewires, various types of catheters including balloon catheters, stent delivery systems, stent retrievers, embolization coils, liquid embolics, aspiration pumps, device to deliver contrast media, medicine, hemostasis valve adapters, syringes, stopcocks, inflation device, etc.) to allow the user or operator  11  to perform a catheter-based medical procedure via a robotic system by operating various controls such as the controls and inputs located at the control station  26 . Bedside unit  20 , and in particular robotic drive  24 , may include any number and/or combination of components to provide bedside unit  20  with the functionality described herein. A user or operator  11  at control station  26  is referred to as the control station user or control station operator and referred to herein as user or operator. A user or operator at bedside unit  20  is referred to as bedside unit user or bedside unit operator. The robotic drive  24  includes a plurality of device modules  32   a - d  mounted to a rail or linear member  60  (shown in  FIG. 3 ). The rail or linear member  60  guides and supports the device modules. Each of the device modules  32   a - d  may be used to drive an EMD such as a catheter or guidewire. For example, the robotic drive  24  may be used to automatically feed a guidewire into a diagnostic catheter and into a guide catheter in an artery of the patient  12 . One or more devices, such as an EMD, enter the body (e.g., a vessel) of the patient  12  at an insertion point  16  via, for example, an introducer sheath. 
     Bedside unit  20  is in communication with control station  26 , allowing signals generated by the user inputs of control station  26  to be transmitted wirelessly or via hardwire to bedside unit  20  to control various functions of bedside unit  20 . As discussed below, control station  26  may include a control computing system  34  (shown in  FIG. 2 ) or be coupled to the bedside unit  20  through a control computing system  34 . Bedside unit  20  may also provide feedback signals (e.g., loads, speeds, operating conditions, warning signals, error codes, etc.) to control station  26 , control computing system  34  (shown in  FIG. 2 ), or both. Communication between the control computing system  34  and various components of the catheter-based procedure system  10  may be provided via a communication link that may be a wireless connection, cable connections, or any other means capable of allowing communication to occur between components. Control station  26  or other similar control system may be located either at a local site (e.g., local control station  38  shown in  FIG. 2 ) or at a remote site (e.g., remote control station and computer system  42  shown in  FIG. 2 ). Catheter procedure system  10  may be operated by a control station at the local site, a control station at a remote site, or both the local control station and the remote control station at the same time. At a local site, user or operator  11  and control station  26  are located in the same room or an adjacent room to the patient  12  and bedside unit  20 . As used herein, a local site is the location of the bedside unit  20  and a patient  12  or subject (e.g., animal or cadaver) and the remote site is the location of a user or operator  11  and a control station  26  used to control the bedside unit  20  remotely. A control station  26  (and a control computing system) at a remote site and the bedside unit  20  and/or a control computing system at a local site may be in communication using communication systems and services  36  (shown in  FIG. 2 ), for example, through the Internet. In an embodiment, the remote site and the local (patient) site are away from one another, for example, in different rooms in the same building, different buildings in the same city, different cities, or other different locations where the remote site does not have physical access to the bedside unit  20  and/or patient  12  at the local site. 
     Control station  26  generally includes one or more input modules  28  configured to receive user inputs to operate various components or systems of catheter-based procedure system  10 . In the embodiment shown, control station  26  allows the user or operator  11  to control bedside unit  20  to perform a catheter-based medical procedure. For example, input modules  28  may be configured to cause bedside unit  20  to perform various tasks using percutaneous intervention devices (e.g., EMDs) interfaced with the robotic drive  24  (e.g., to advance, retract, or rotate a guidewire, advance, retract or rotate a catheter, inflate or deflate a balloon located on a catheter, position and/or deploy a stent, position and/or deploy a stent retriever, position and/or deploy a coil, inject contrast media into a catheter, inject liquid embolics into a catheter, inject medicine or saline into a catheter, aspirate on a catheter, or to perform any other function that may be performed as part of a catheter-based medical procedure). Robotic drive  24  includes various drive mechanisms to cause movement (e.g., axial and rotational movement) of the components of the bedside unit  20  including the percutaneous intervention devices. 
     In one embodiment, input modules  28  may include one or more touch screens, joysticks, scroll wheels, and/or buttons. In addition to input modules  28 , the control station  26  may use additional user controls  44  (shown in  FIG. 2 ) such as foot switches and microphones for voice commands, etc. Input modules  28  may be configured to advance, retract, or rotate various components and percutaneous intervention devices such as, for example, a guidewire, and one or more catheters or microcatheters. Buttons may include, for example, an emergency stop button, a multiplier button, device selection buttons and automated move buttons. When an emergency stop button is pushed, the power (e.g., electrical power) is shut off or removed to bedside unit  20 . When in a speed control mode, a multiplier button acts to increase or decrease the speed at which the associated component is moved in response to a manipulation of input modules  28 . When in a position control mode, a multiplier button changes the mapping between input distance and the output commanded distance. Device selection buttons allow the user or operator  11  to select which of the percutaneous intervention devices loaded into the robotic drive  24  are controlled by input modules  28 . Automated move buttons are used to enable algorithmic movements that the catheter-based procedure system  10  may perform on a percutaneous intervention device without direct command from the user or operator  11 . In one embodiment, input modules  28  may include one or more controls or icons (not shown) displayed on a touch screen (that may or may not be part of a display  30 ), that, when activated, causes operation of a component of the catheter-based procedure system  10 . Input modules  28  may also include a balloon or stent control that is configured to inflate or deflate a balloon and/or deploy a stent. Each of the input modules  28  may include one or more buttons, scroll wheels, joysticks, touch screen, etc. that may be used to control the particular component or components to which the control is dedicated. In addition, one or more touch screens may display one or more icons (not shown) related to various portions of input modules  28  or to various components of catheter-based procedure system  10 . 
     Control station  26  may include a display  30 . In other embodiments, the control station  26  may include two or more displays  30 . Display  30  may be configured to display information or patient specific data to the user or operator  11  located at control station  26 . For example, display  30  may be configured to display image data (e.g., X-ray images, MRI images, CT images, ultrasound images, etc.), hemodynamic data (e.g., blood pressure, heart rate, etc.), patient record information (e.g., medical history, age, weight, etc.), lesion or treatment assessment data (e.g., IVUS, OCT, FFR, etc.). In addition, display  30  may be configured to display procedure specific information (e.g., procedural checklist, recommendations, duration of procedure, catheter or guidewire position, volume of medicine or contrast agent delivered, etc.). Further, display  30  may be configured to display information to provide the functionalities associated with control computing system  34  (shown in  FIG. 2 ). Display  30  may include touch screen capabilities to provide some of the user input capabilities of the system. 
     Catheter-based procedure system  10  also includes an imaging system  14 . Imaging system  14  may be any medical imaging system that may be used in conjunction with a catheter based medical procedure (e.g., non-digital X-ray, digital X-ray, CT, MRI, ultrasound, etc.). In an exemplary embodiment, imaging system  14  is a digital X-ray imaging device that is in communication with control station  26 . In one embodiment, imaging system  14  may include a C-arm (shown in  FIG. 1 ) that allows imaging system  14  to partially or completely rotate around patient  12  in order to obtain images at different angular positions relative to patient  12  (e.g., sagittal views, caudal views, anterior-posterior views, etc.). In one embodiment imaging system  14  is a fluoroscopy system including a C-arm having an X-ray source  13  and a detector  15 , also known as an image intensifier. 
     Imaging system  14  may be configured to take X-ray images of the appropriate area of patient  12  during a procedure. For example, imaging system  14  may be configured to take one or more X-ray images of the head to diagnose a neurovascular condition. Imaging system  14  may also be configured to take one or more X-ray images (e.g., real time images) during a catheter-based medical procedure to assist the user or operator  11  of control station  26  to properly position a guidewire, guide catheter, microcatheter, stent retriever, coil, stent, balloon, etc. during the procedure. The image or images may be displayed on display  30 . For example, images may be displayed on display  30  to allow the user or operator  11  to accurately move a guide catheter or guidewire into the proper position. 
     In order to clarify directions, a rectangular coordinate system is introduced with X, Y, and Z axes. The positive X axis is oriented in a longitudinal (axial) distal direction, that is, in the direction from the proximal end to the distal end, stated another way from the proximal to distal direction. The Y and Z axes are in a transverse plane to the X axis, with the positive Z axis oriented up, that is, in the direction opposite of gravity, and the Y axis is automatically determined by right-hand rule. 
       FIG. 2  is a block diagram of catheter-based procedure system  10  in accordance with an exemplary embodiment. Catheter-procedure system  10  may include a control computing system  34 . Control computing system  34  may physically be, for example, part of control station  26  (shown in  FIG. 1 ). Control computing system  34  may generally be an electronic control unit suitable to provide catheter-based procedure system  10  with the various functionalities described herein. For example, control computing system  34  may be an embedded system, a dedicated circuit, a general-purpose system programmed with the functionality described herein, etc. Control computing system  34  is in communication with bedside unit  20 , communications systems and services  36  (e.g., Internet, firewalls, cloud services, session managers, a hospital network, etc.), a local control station  38 , additional communications systems  40  (e.g., a telepresence system), a remote control station and computing system  42 , and patient sensors  56  (e.g., electrocardiogram (ECG) devices, electroencephalogram (EEG) devices, blood pressure monitors, temperature monitors, heart rate monitors, respiratory monitors, etc.). The control computing system is also in communication with imaging system  14 , patient table  18 , additional medical systems  50 , contrast injection systems  52  and adjunct devices  54  (e.g., IVUS, OCT, FFR, etc.). The bedside unit  20  includes a robotic drive  24 , a positioning system  22  and may include additional controls and displays  46 . As mentioned above, the additional controls and displays may be located on a housing of the robotic drive  24 . Interventional devices and accessories  48  (e.g., guidewires, catheters, etc.) interface to the bedside system  20 . In an embodiment, interventional devices and accessories  48  may include specialized devices (e.g., IVUS catheter, OCT catheter, FFR wire, diagnostic catheter for contrast, etc.) which interface to their respective adjunct devices  54 , namely, an IVUS system, an OCT system, and FFR system, etc. 
     In various embodiments, control computing system  34  is configured to generate control signals based on the user&#39;s interaction with input modules  28  (e.g., of a control station  26  (shown in  FIG. 1 ) such as a local control station  38  or a remote control station  42 ) and/or based on information accessible to control computing system  34  such that a medical procedure may be performed using catheter-based procedure system  10 . The local control station  38  includes one or more displays  30 , one or more input modules  28 , and additional user controls  44 . The remote control station and computing system  42  may include similar components to the local control station  38 . The remote  42  and local  38  control stations can be different and tailored based on their required functionalities. The additional user controls  44  may include, for example, one or more foot input controls. The foot input control may be configured to allow the user to select functions of the imaging system  14  such as turning on and off the X-ray and scrolling through different stored images. In another embodiment, a foot input device may be configured to allow the user to select which devices are mapped to scroll wheels included in input modules  28 . Additional communication systems  40  (e.g., audio conference, video conference, telepresence, etc.) may be employed to help the operator interact with the patient, medical staff (e.g., angio-suite staff), and/or equipment in the vicinity of the bedside. 
     Catheter-based procedure system  10  may be connected or configured to include any other systems and/or devices not explicitly shown. For example, catheter-based procedure system  10  may include image processing engines, data storage and archive systems, automatic balloon and/or stent inflation systems, medicine injection systems, medicine tracking and/or logging systems, user logs, encryption systems, systems to restrict access or use of catheter-based procedure system  10 , etc. 
     As mentioned, control computing system  34  is in communication with bedside unit  20  which includes a robotic drive  24 , a positioning system  22  and may include additional controls and displays  46 , and may provide control signals to the bedside unit  20  to control the operation of the motors and drive mechanisms used to drive the percutaneous intervention devices (e.g., guidewire, catheter, etc.). The various drive mechanisms may be provided as part of a robotic drive  24 .  FIG. 3  is a perspective view of a robotic drive for a catheter-based procedure system  10  in accordance with an embodiment. In  FIG. 3 , a robotic drive  24  includes multiple device modules  32   a - d  coupled to a linear member  60 . Each device module  32   a - d  is coupled to the linear member  60  via a stage  62   a - d  moveably mounted to the linear member  60 . A device module  32   a - d  may be connected to a stage  62   a - d  using a connector such as an offset bracket  78   a - d . In another embodiment, the device module  32   a - d  is directly mounted to the stage  62   a - d . Each stage  62   a - d  may be independently actuated to move linearly along the linear member  60 . Accordingly, each stage  62   a - d  (and the corresponding device module  32   a - d  coupled to the stage  62   a - d ) may independently move relative to each other and the linear member  60 . A drive mechanism is used to actuate each stage  62   a - d . In the embodiment shown in  FIG. 3 , the drive mechanism includes independent stage translation motors  64   a - d  coupled to each stage  62   a - d  and a stage drive mechanism  76 , for example, a lead screw via a rotating nut, a rack via a pinion, a belt via a pinion or pulley, a chain via a sprocket, or the stage translation motors  64   a - d  may be linear motors themselves. In some embodiments, the stage drive mechanism  76  may be a combination of these mechanisms, for example, each stage  62   a - d  could employ a different type of stage drive mechanism. In an embodiment where the stage drive mechanism is a lead screw and rotating nut, the lead screw may be rotated and each stage  62   a - d  may engage and disengage from the lead screw to move, e.g., to advance or retract. In the embodiment shown in  FIG. 3 , the stages  62   a - d  and device modules  32   a - d  are in a serial drive configuration. 
     Each device module  32   a - d  includes a drive module  68   a - d  and a cassette  66   a - d  mounted on and coupled to the drive module  68   a - d . In the embodiment shown in  FIG. 3 , each cassette  66   a - d  is mounted to the drive module  68   a - d  in a vertical orientation. In other embodiments, each cassette  66   a - d  may be mounted to the drive module  68   a - d  in other mounting orientations. Each cassette  66   a - d  is configured to interface with and support a proximal portion of an EMD (not shown). In addition, each cassette  66   a - d  may include elements to provide one or more degrees of freedom in addition to the linear motion provided by the actuation of the corresponding stage  62   a - d  to move linearly along the linear member  60 . For example, the cassette  66   a - d  may include elements that may be used to rotate the EMD when the cassette is coupled to the drive module  68   a - d . Each drive module  68   a - d  includes at least one coupler to provide a drive interface to the mechanisms in each cassette  66   a - d  to provide the additional degree of freedom. Each cassette  66   a - d  also includes a channel in which a device support  79   a - d  is positioned, and each device support  79   a - d  is used to prevent an EMD from buckling. A support arm  77   a ,  77   b , and  77   c  is attached to each device module  32   a ,  32   b , and  32   c , respectively, to provide a fixed point for support of a proximal end of the device supports  79   b ,  79   c , and  79   d , respectively. The robotic drive  24  may also include a device support connection  72  connected to a device support  79 , a distal support arm  70  and a support arm  77   o . Support arm  77   o  is used to provide a fixed point for support of the proximal end of the distal most device support  79   a  housed in the distal most device module  32   a . In addition, an introducer interface support (redirector)  74  may be connected to the device support connection  72  and an EMD (e.g., an introducer sheath). The configuration of robotic drive  24  has the benefit of reducing volume and weight of the drive robotic drive  24  by using actuators on a single linear member. 
     To prevent contaminating the patient with pathogens, healthcare staff use aseptic technique in a room housing the bedside unit  20  and the patient  12  or subject (shown in  FIG. 1 ). A room housing the bedside unit  20  and patient  12  may be, for example, a cath lab or an angio suite. Aseptic technique consists of using sterile barriers, sterile equipment, proper patient preparation, environmental controls and contact guidelines. Accordingly, all EMDs and interventional accessories are sterilized and can only be in contact with either sterile barriers or sterile equipment. In an embodiment, a sterile drape (not shown) is placed over the non-sterile robotic drive  24 . Each cassette  66   a - d  is sterilized and acts as a sterile interface between the draped robotic drive  24  and at least one EMD. Each cassette  66   a - d  can be designed to be sterile for single use or to be re-sterilized in whole or part so that the cassette  66   a - d  or its components can be used in multiple procedures. 
     As mentioned, the linear movement of each device module  32   a - d  along the rail or linear member  60  may be independently controlled. In an embodiment, the range of linear motion of each of the different device modules along the rail  60  can overlap. In other words, the range of positions where different device module can be located along the rail  60  can overlap such that different device modules can occupy the same space at different times, although not at the same time. In one embodiment, two successive device modules (e.g.,  32   a  and  32   b ,  32   b  and  32   c ,  32   c  and  32   d ) can have overlapping ranges of linear motion. In another embodiment, non-successive modules (e.g.,  32   a  and  32   c  or  32   b  and  32   d ) can have overlapping ranges of linear motion. 
     As mentioned, each cassette  66   a - d  of each device module  32   a - d  is configured to interface with and support a proximal portion of an EMD. In various embodiments, different numbers and types of EMDs may be utilized in the robotic drive  24  based on, for example, the type of procedure being performed using the robotic drive  24 . For example, an EMD may be positioned in the first device module  32   a , while the second  32   b , third  32   c , and fourth  32   d  device modules are unpopulated. In various other embodiments, any combination of populated device modules may be implemented using robotic drive  24  such as for example, populating the first  32   a  and second  32   b  device module with an EMD, populating the first  32   a  and fourth  32   d  device module with an EMD, populating the first  32   a , second  32   b  and third  32   c  device module with an EMD, populating the first  32   a , third  32   c  and fourth  32   d  device module with an EMD, populating the first  32   a , second  32   b  and fourth  32   d  device module with an EMD, populating the first  32   a , second  32   b , and fourth  32   d  device module with an EMD, etc. In addition, each device module  32   a - d  may receive different types of EMDs, including but limited to, a sheath (also referred to as a long sheath), a guide catheter, a balloon guide catheter, a guiding sheath, a diagnostic guidewire (also known as a angiographic guidewire), an intermediate catheter, a support catheter, a digital access catheter, an aspiration catheter, a microcatheter, a delivery catheter, a wire-based EMD (e.g., a guidewire, a microwire, a stent retriever, an embolization coil), etc. In some embodiments, the specific configuration of populated device modules and the specific types of EMDs, may be changed during a procedure, i.e., a procedure may utilize more than one configurations. 
     Hub driving or proximal driving refers to holding on to and manipulating an EMD from a proximal position (e.g., geared adapter on catheter hub). In one embodiment, hub driving refers to imparting a force or torque to the hub of a catheter to translate and/or rotate the catheter. In hub driving, often applying typical clinical loads would cause the EMD to buckle. Because of this, hub driving often requires additional anti-buckling features incorporated into the EMD or driving mechanism. For EMDs that do not have hubs or other interfaces (e.g., guidewire), device adapters may be added to the device to act as a temporary hub. Shaft driving refers to holding on to and manipulating an EMD along its shaft. For example, an on-device adapter may be placed just proximal of the hub or Y-connector the device is inserted into. If the location of the on-device adapter is at the proximity of an insertion point (to the body or another catheter, or valve), shaft driving does not typically require anti-buckling features (but may include anti-buckling features to improve drive capability). This type of shaft driving can be referred to as distal driving. In  FIG. 3 , each drive module  32   a - d  is configured to hub drive an EMD. However, in various embodiments described further below, the robotic drive  24  or one/or more device modules  32   a - d  may be configured to provide one or more EMDs that are shaft driven. As mentioned above, in  FIG. 3  the drive modules  32   a - d  are in a serial drive configuration (e., over-the-wire (OTW). A serial drive configuration or layout uses actuators (or drives) to drive an EMD into a more distal EMD hub. EMDs may also be driven in a parallel configuration or layout. A parallel configuration or layout uses serial actuators (or drives) to drive two or more EMDs into a common EMD hub. Serial and parallel configurations can be added together in different combinations. In various embodiments described further below, the robotic drive  24  and/or one or more drive modules  32   a - d  may be configured to provide one or more drive modules  32   a - d  or EMDs in a parallel drive configuration (e.g., rapid exchange). 
     In an alternative embodiment, a separate rail or linear member may be used to support and translate each stage  62   a - d  and device module  32   a - d .  FIG. 4  is a perspective view of a portion of a robotic drive for a catheter procedure system in accordance with an embodiment. Robotic drive  25  includes a device module  32   a  coupled to a first rail or linear member  80  using a stage  62   a , a device module  32   b  coupled to a second rail or linear member  82  using a stage  62   b  and a device module  32   c  coupled to a third rail or linear member  84  using a stage  62   c . The first rail  60 , second rail  82  and third rail  84  are parallel to one another. A first stage translation motor  86  is used to translate a stage  62   a  along the first rail  80 , a second stage translation motor  88  is used to translate a stage  62   b  along the second rail  82  and a third stage translation motor  90  is used to translate a stage  62   b  along the third rail  84 . One advantage of the configuration shown in  FIG. 4  is that the stage translation motors used for linear translation are fixed. Accordingly, the mass of the moving device modules  32   a - c  and stages  62   a - c  is reduced and relocation to a more beneficial point (i.e., towards the back of the rail to help react moment loading). In various other embodiments described below with respect to  FIGS. 71-77 , a robotic drive with multiple parallel rails may be configured to allow device modules to pass each other. 
     As mentioned above, each device module  32   a - d  includes a drive module  68   a - d  and a cassette  66   a - d  mounted on and coupled to the corresponding drive module  68   a - d . Each cassette  66   a - d  is releasably coupled to a drive module  68   a - d .  FIG. 5  is a perspective view of a drive module attached to a stage in accordance with an embodiment and  FIG. 6  is a side cross-sectional view of a drive module in accordance with an embodiment. Referring to  FIGS. 5 and 6 , the drive module includes a mounting surface  92  and a coupler  98 . A motor  94  is connected to the coupler  98  via, for example, a belt  96 . The motor  94  and belt  96  are used to change the rotational position of the coupler  98 . In an embodiment, coupler  98  rotates about a coupler axis  99 . Drive module  68  may include an encoder (not shown) for device position feedback. The drive module  68  shown in  FIGS. 5 and 6  has one coupler  98 , however, it should be understood that the drive module  68  may have more than one coupler  98  and more than one motor  94 , as described further below. The rotation of the coupler  98  may be used to provide another degree of freedom to an elongated medical device positioned in a cassette mounted on the mounting surface  92  so as to interface with the coupler  98 . For example, the coupler  98  may be used to rotate an elongated medical device in the cassette. Alternatively, the coupler  98  may be used to translate an elongated medical device. If the drive module  68  has two or more couplers  98 , each coupler may be used to provide a different degree of freedom for one elongated medical device or multiple elongated medical devices coupled to the same drive module. As mentioned, a cassette  66  (shown in  FIG. 3 ) may be positioned on the mounting surface  92  of the drive module  68  and used to interface with an elongated medical device positioned in the cassette. As described further below with respect to  FIG. 100 , in an embodiment the drive module  68  may also include one or more additional elements (not shown) on the mounting surface  92  such as, for example, positioning pins, alignment pins, locking pins, etc. to interact with elements on a cassette  66  mounted on the drive module  68  to enable a releasable attachment of the cassette  66  to the drive module  68 . 
       FIG. 7  is a perspective view of an exemplary cassette in accordance with an embodiment. In  FIG. 7 , the cassette  91  includes a housing  93 . The housing includes a cradle  95  configured to receive an elongated medical device. A bevel gear  97  is used to interface with a coupler  98  (shown in  FIG. 5 ) of a drive module and to interface with the elongated medical device to rotate the elongated medical device. In other embodiments, a cassette may be configured to provide a linear degree of freedom or a cassette may be configured to provide two or more degrees of freedom.  FIG. 8  is a top view of an exemplary cassette attached to a drive module in accordance with an embodiment. In  FIG. 8 , the cassette  101  includes a pair of tires  103 ,  105  which can be connected to the coupler  98  (not shown) of a drive module. The pair of tires  103 ,  105  may be used to provide linear motion to an elongated medical device positioned in a channel  107 . An embodiment of a device module including a cassette  101  is described further below with respect to  FIGS. 66-69 .  FIG. 9  is a top view of an exemplary cassette attached to a drive module which is connected to a stage in accordance with an embodiment. In  FIG. 9 , the cassette  111  is configured to provide two degrees of freedom in addition to the translation of the assembly. For example, cassette  111  may be configured to provide rotation and to pinch and unpinch an elongated medical device  113  positioned in a channel  115 . Such as cassette may be mounted to, for example, a drive module with two or more couplers. Embodiments of a device module including a cassette  111  and a drive module with two or more couplers are described further below with respect to  FIGS. 43-47 . In another embodiment described further below with respect to  FIGS. 48 and 49 , two individual drive modules, either mechanically or electrically coupled together, can provide two degrees of freedom for the cassette  111 . 
     As shown in  FIG. 1 , one or more EMDs may enter the body of a patient (e.g., a vessel) at an insertion point  16  using, for example, an introducer and introducer sheath. The introducer sheath typically orients at an angle, usually less than 45 degrees, to the axis of the vessel in a patient  120  (shown in  FIGS. 10-12 ). Any height difference between where the EMD enters the body (the introducer sheath&#39;s proximal opening  126  shown in  FIG. 10 ) and the longitudinal drive axis of the robotic drive  124  will directly affect the working length for the elongated medical device. The more an elongated medical device needs to compensate for differences in displacement and angle, the less the elongated medical device will be able to enter the body when the robotic drive is at its maximum distal (forward) position. It is beneficial to have a robotic drive that is at the same height and angle as the introducer sheath.  FIG. 10  is a diagram illustrating an elongated medical device axis of manipulation and the introductory point into the patient.  FIG. 10  shows a height difference (d)  123  between the proximal end  126  of the introducer sheath  122  and the longitudinal device axis and an angular difference ( 0 )  128  between the introducer sheath  122  and the longitudinal device axis  125  of the robotic drive  124 . The elongated medical device  121  is constrained on each axis and creates a curve with tangentially aligned end points. The length of this curve represents a length of the elongated medical device  121  that cannot be driven any further forward by the robotic drive  124  and cannot enter the introducer sheath  122  due to the misalignment. A higher angle ( 0 )  128  also leads to higher device friction. In general, lower angular misalignment ( 0 )  128 , and linear misalignment d  123  can lead to reduced friction and reduced loss of working length. While  FIG. 10  illustrates a simplified example illustrating one linear and one rotational offset, it should be understood that this problem occurs in three dimensions, namely, three linear offsets and three rotational offsets. The thickness of the robotic drive  124  also plays a role in determining the location of the longitudinal device axis  125  relative to the introducer sheath  122 . 
       FIGS. 11 a  and 11 b    are diagrams illustrating the effect of the thickness of a drive module, or robotic drive as a whole, on the loss of working length.  FIG. 11 a    shows the location of the longitudinal device axis  125  of a robotic drive  124  relative to the introducer sheath  122 , indicated by d  123 , when the robotic drive  124  is thick as shown by the distance (X)  129  between an upper surface and a bottom surface of the robotic drive  124 .  FIG. 11 b    shows the location of the longitudinal device axis  125  of a robotic drive  124  relative to the introducer sheath  122 , indicated by a shorter d  123 , when the robotic drive  124  is shallow as shown by the distance (X)  129  between an upper surface and a bottom surface of the robotic drive  124 . Reducing the thickness of the robotic drive  124  to get close to the patient and introducer sheath reduces the distance  123  between introducer sheath axis and device axis and reduces the loss of working length of the elongated medical device.  FIG. 12  is a diagram illustrating an exemplary orientation to minimize loss of working length. In  FIG. 12 , the robotic drive is positioned to align the longitudinal device axis  125  of the robotic drive  124  to that of the introducer sheath  122 . This eliminates loss of working length due to angular and linear misalignment of the elongated medical device. However, this position for the robotic drive  124  may not be practical due to the length and size of the robotic drive  124 . Orienting a robotic drive at a sharp angle also affects the usability by making it difficult to load and unload elongated medical devices, and adjust and handle the robotic drive. 
     To reduce the distance between the robotic drive and the patient and the distance between the longitudinal device axis of the robotic drive and the introducer sheath, the cassette of a device module  3  (shown in  FIG. 3 ) may be mounted to the drive module in a horizontal orientation.  FIG. 13  is a perspective view of a device module with a horizontally mounted cassette in accordance with an embodiment and  FIG. 14  is a rear perspective view of a device module with a horizontally mounted cassette in accordance with an embodiment. In  FIGS. 13 and 14 , a device module  132  includes a cassette  138  that is horizontally mounted to a drive module  140 . The device module  132  is connected to a stage  136  that is moveably mounted to a rail or linear member  134 . The drive module  140  includes a coupler  142  that is used to provide a power interface to the cassette  138  to, for example, rotate an elongated medical device (not shown) positioned in the cassette. The coupler  142  rotates about an axis  143 . By mounting the cassette  138  horizontally, the drive module  140  that the cassette  138  attaches to located off to the side and no longer positioned between the cassette  138  and the patient.  FIG. 15  is a front view of a distal end of a device module with a horizontally mounted cassette in accordance with an embodiment. In  FIG. 15 , a distance  146  between the device axis of the elongated medical device  144  and the bottom surface of the device module  132  is shown. The horizontal mounting of the cassette  138  eliminates the need for the drive module  140  to be placed under the device axis and between the elongated medical device  144  and the patient. Rather, only a portion of the cassette  138  is positioned between the elongated medical device  138  and the patient. Horizontally mounting the cassette  138  also reduces the distance  146  between the elongated medical device and bottom surface of the device module  132  which allows the robotic drive to get closer to the patient and reduces loss of working length in an elongated medical device. By comparison,  FIG. 16  is a front view of a distal end of a device module with a vertically mounted cassette in accordance with an embodiment. In  FIG. 16 , a device module  132  is shown where the cassette  138  is vertically mounted to a drive module  140 . The drive module  140  is under the cassette  138  and increases the distance  148  between the device axis of the elongated medical device  144  and the bottom surface of the device module  132 . This can prevent the device axis from being as close to the introducer (not shown) as possible. A drive module  140  positioned under the cassette  138  may also interfere with the patient. In various other embodiment, a cassette may be mounted to the drive module at any angle. In yet another embodiment, the cassette may be mounted vertically on an underside of the drive module to eliminate the need for a drive module between the device axis and the patient. 
     In order to reduce the length of the rail or linear member  60  (shown in  FIG. 3 ) of the robotic drive system  24  (shown in  FIG. 3 ), offset brackets  78  (shown in  FIG. 3 ) may be used to create offsets between a stage and a device module to reduce gaps between stages on the linear member when cassettes are brought together.  FIG. 17  is a block diagram illustrating an occupied length on a linear member without offsets between device modules and stages in accordance with an embodiment. As mentioned above, in one embodiment a device module may be directly mounted to a stage with no offset between the device module and the stage. In  FIG. 17 , four device modules  150  are shown and each device module  150  includes a cassette  152  mounted to a drive module  154 . Each device module  150  is directly connected to a stage  156  which is coupled to a rail or linear member  158 . When the device modules  150  are brought close together along the rail  158 , the stages  156  for each device module  150  are also brought closer together. However, as shown in  FIG. 17 , the length of each cassette  152  of each device module  150  may limit how close each stage  156  may be brought to another stage  156  on the rail. The four stages  156  (plus safety cushions on each side) define an occupied rail length  160  which affects the overall length required for the rail  158 . The occupied rail length and the overall length of the rail  158  may be shortened by using offsets and offset brackets as shown in  FIGS. 18A-21 . 
       FIG. 18A  is a block diagram illustrating occupied length on a linear member with offsets between device modules and stages in accordance with an embodiment. In  FIG. 18A , four device modules  150  are shown and each device module  150  includes a cassette  152  mounted to a drive module  154 . Each device module  150  is connected to an offset bracket  168 ,  170 ,  172 ,  174  which is used to connect the device module  150  to a stage  156 . Each stage is coupled to a rail or linear member  158 . When brought close together the four stages  156  define an occupied rail length  162  which, as mentioned, affects the overall length required for the rail  158 . Each offset bracket  168 ,  170 ,  172 ,  174  defines an offset distance from the center of the respective stage  156  to which it is attached to a center of the cassette  152  of the device module  150  attached to the stage  156 . For example, a first offset bracket  168  defines a first offset  164  between the center of the associated stage  156  and the center of the associated cassette  152 . A fourth offset bracket  174  may be configured to define an offset that is the same as the first offset  164  distance or a different offset distance. A third offset bracket  172  defines a second offset  166  between the center of the associated stage  156  and the center of the associated cassette  152 . A second offset bracket  170  may be configured to define an offset that is the same as the second offset  166  distance or a different offset. The offsets allows the stages  156  to be brought towards the center of the rail  158  which reduces the overall length of the robotic drive.  FIG. 18A  shows one embodiment of the configuration of the offset brackets, however, in other embodiments, different offset bracket configurations may be used, for example, as shown in  FIGS. 18B and 18C . In  FIG. 18B , each offset bracket  171 ,  173 ,  175 ,  177  positioned along a linear member or rail  159  extends away from a distal end of the linear member  159  in a distal direction (i.e., forward facing) towards the patient. This configuration can allow the linear member  159  (and other elements of the robotic drive) to be farther away from an access site in the patient and an imaging system of the catheter procedure system. In  FIG. 18C  each offset bracket  181 ,  183 ,  185 ,  187  positioned along a linear member  159  extends towards a proximal end of the linear member or rail  159  in a proximal direction (i.e., backward facing) away from the patient.  FIG. 19  is a side view of a robotic drive with offsets brackets in accordance with an embodiment.  FIG. 20  is an isometric view of a robotic drive with offset brackets in accordance with an embodiment.  FIG. 21  is a top view of a robotic drive with offset brackets in accordance with an embodiment. In  FIGS. 19-21 , offset brackets  168 ,  170 ,  172  and  174  are used to compensate for the lengths of the cassettes  152  so as to eliminate dead space between the stages  156 . The offsets created by the offset brackets  168 ,  170 ,  172  and  174  are used to minimize the length of the rail or linear member  158  by eliminating dead space between the stages  156 . In addition, if the length of a stage  156  is greater than the length of the device module  150 , the offsets may be used to compensate for differences in length between the stage  156  and device module  150 . 
       FIG. 22  is a top view of a portion of a robotic drive configured to drive four elongated medical devices in accordance with an embodiment. In  FIG. 22 , the portion of the robotic drive  200  includes four device modules, in particular, a first device module  202  with a first cassette  210 , a second device module  204  with a second cassette  212 , a third device module  206  with a third cassette  214  and a fourth device module  208  with a fourth cassette  216 . The robotic drive  200  is configured to drive four elongated medical devices and accordingly, each cassette  210 ,  212 ,  214  and  216  is populated with an elongated medical device. For example, a first elongated medical device  218  may be positioned in the first cassette  210  and may be, for example, a guide catheter that is configured to receive the three proximal elongated medical devices in a lumen of the guide catheter. A second elongated medical device  220  may be positioned in the second cassette  212  and may be, for example, a distal access or a diagnostic catheter that is configured to receive the two proximal elongated medical devices in a lumen of the distal access catheter. A third elongated medical device  222  may be positioned in the third cassette  214  and may be, for example, an over-the-wire balloon catheter or a microcatheter that is configured to receive the most proximal elongated medical device in a lumen of the elongated medical device  222 . A fourth elongated medical device  224  may be positioned in the fourth cassette  216  and may be, for example, a guidewire. In order to support different numbers and configurations of elongated medical devices for different procedures, in one embodiment each cassette may be similar and an on-device adapter may be used to interface the elongated medical device to a cassette. For example, different steps of an endovascular procedure may require different numbers of elongated medical devices. A procedure may start with two coaxial catheters (a bi-coaxial catheter or bi-axial configuration) and a guidewire, then exchange to a configuration with three coaxial catheters (a tri-coaxial catheter or tri-axial configuration) and a guidewire, and subsequently back to a bi-axial catheter system and a guidewire. As used herein, the terms tri-axial, bi-axial and mono-axial refer to the number of serially concentric catheters but not including any wire based EMDs. When fewer elongated medical devices are used in a procedure, the device module in which an elongated medical device is positioned may be changed without requiring the removal of a cassette to change positions and unpopulated cassettes do not need to be removed from the robotic drive. Rather, the elongated medical devices and the on-device adapters between the elongated medical device and the cassette may be moved between unpopulated cassettes. 
       FIG. 23  is a perspective view of a catheter with an on-device adapter in accordance with an embodiment and  FIG. 24  is a perspective view of a guidewire with an on-device adapter in accordance with an embodiment. As used herein, an on-device adapter is a sterile apparatus capable of releasably clamping to an EMD to provide a driving interface. In  FIG. 23 , a catheter  230  includes a hemostasis valve or hub (e.g., a rotating hemostasis valve)  234  on the proximal end  236  of the catheter  230 . An on-device adapter  232  is positioned on the catheter  230  distal to the hemostasis value  234  on the proximal end  236  of the catheter. In the embodiment of  FIG. 23 , the external surface of the on-device adapter is formed as a gear. The gear feature of the on-device adapter  232  is configured to interact with a gear  97  (shown in  FIG. 7 ) of a cassette, for example, cassette  91  shown in  FIG. 7 . When power is transferred from a device module (not shown) to the gear in the cassette (e.g., via a coupler), the gear in the cassette interacts with the gear  232  on the catheter  230  to rotate the catheter. In another embodiment, rotation of the on-device adapter  232  may be configured to pinch/unpinch the catheter  230 . In an embodiment, an internal surface of the on-device adapter  232  is firmly attached to a standard luer section of the elongated medical device (e.g., catheter  230 ). In another embodiment, the internal surface of the on-device adapter is clamped to a lateral surface it the proximal end of the elongated medical device. In another embodiment, the on-device adapter is attached to a cylindrical section (shaft) of the EMD. In yet another embodiment, the on-device adapter is not directly attached to the EMD, by is attached to the EMD via an interface. The power can transfer from the cassette to the on-device adapter in different ways such as, for example, gears (as mentioned above), or friction surface (e.g., tire and roller), belt, pneumatic, or magnetic/electromagnetic coupling. 
     In  FIG. 24 , a guidewire  240  is shown with an on-device adapter  242 . In the embodiment of  FIG. 24 , the on-device adapter  242  is a collet with a gear  244  on the proximal end  246  of the collet. The collet  242  is configured to grip the guidewire  240 . The term collet as used herein is a device to releasably fix a portion of an EMD thereto. In one embodiment the collet includes at least two members that move relative to each other to releasably fix the EMD to at least one of the two members. Fixed means no intentional relative movement of the collet and EMD during operation parameters. The gear  244  is configured to interact with a gear  97  (shown in  FIG. 7 ) of a cassette, for example, cassette  91  shown in  FIG. 7 . When power is transferred from a device module (not shown) to the gear in the cassette (e.g., via a coupler), the gear in the cassette interacts with the gear  244  on the guidewire  240  to rotate the guidewire  240 . In another embodiment, rotation of the on-device adapter  242  via gear  244  may be configured to pinch/unpinch the guidewire  240 . The elongated medical device and on-device adapter may be positioned in the cassette as shown in  FIG. 25 . In  FIG. 25 , a guide wire  240  and collet  242  are positioned in a cradle  252  of the cassette  250 . 
     As mentioned, the elongated medical device and the on-device adapter may be removed from one cassette and moved to another unpopulated cassette.  FIG. 26  shows a guide wire  240  and collet  244  with a gear  244  removed from the cassette  250 . As mentioned, when the cassettes are similar and an on-device adapter is used to interface an elongated medical device to the cassette, the device and on-device adapter may be moved between unpopulated cassettes enabling the number of devices and configuration of the robotic drive to be changed. For example, the number of devices in the exemplary robotic drive  200  in  FIG. 22  may be changed to three devices as shown in  FIG. 27 . In  FIG. 27 , the first cassette  210 , the second cassette  212  and the third cassette  214  are populated with a first elongated medical device  218  (e.g., a guide catheter), second elongated medical device  220  (e.g., a distal access catheter) and a third elongated medical device  222  (e.g., a guidewire), respectively. The fourth cassette  216  is unpopulated and may remain attached to its drive module in the robotic drive. Accordingly, the more proximal cassettes in the robotic drive may be left unpopulated when fewer elongated medical devices need to be actuated for the procedure. In an example, a user may install all the cassettes in a robotic drive at the beginning of a case and does not need to uninstall the cassettes to move devices. The devices (and corresponding on-device adapters may be moved to and from the different cassettes. This can greatly increase usability and exchange speed. In addition, this can make changing device sizes easier. For example, 0.035 and 0.014 wires normally have different collet sizes for manual cases. For the system described with respect to  FIGS. 22-27 , different on-device adapters would allow different sized devices to be driven in the same cassettes. For example, a different sized collet may be used that corresponds with the 0.035 or the 0.014 wire allowing each sized device to be changed and used in any of the cassettes. 
     As mentioned above, linear motion of a device module in the robotic drive may be provided by coupling the device module to a stage connected to a rail or linear member and a stage translation motor. The device module may then be translated linearly by using the stage translating motor to actuate the stage to move along the rail. In another embodiment, linear motion for a first device module may be provided by directly mounting the first device module to a second device module in the robotic drive rather than coupling the first device module to the rail.  FIG. 28A  is a diagram of a first device module mechanically coupled to a second device module to share linear movement of the first device module in accordance with an embodiment. In  FIG. 28A , a first device module  260  with a first drive module  262  is shown. A cassette for the first device module  260  is not shown for simplicity, however, the first device module  260  would also include a cassette mounted on the drive module  262 . In one embodiment, the first drive module  262  includes multiple couplers  271  to provide multiple degrees of freedom to an elongated medical device positioned in a cassette (not shown) mounted on the first drive module  262 . A second device module  264  includes a second drive module  268  and a cassette  266  mounted to the second drive module  268 . In an embodiment, the first device module  260  may be mechanically mounted to the second device module  264 . In another embodiment, the first device module  260  may also be electrically coupled to the second device module  264 . A mount  270  may be used to mechanically couple the first device module  260  to the second device module  264 . The mount  270  may be a kinematic mount such as kinematic mount  272  shown in  FIG. 28B . The mount may be configured to allow the removal of the first device module  260  so that it may be moved and removably mounted to a different device module in the robotic drive to facilitate different configurations of elongated medical devices. For example, the first device module  260  may be manually repositioned by a user to change the number of catheters driven in front of it in the robotic drive.  FIG. 29  is a block diagram illustrating changing a position of a device module in a robotic drive between where the device module is mechanically coupled to another device module in accordance with an embodiment. In  FIG. 29 , a robotic drive  274  includes a first device module  278  that is mounted to a second device module  280 . The second device module  280  is mounted to a rail or linear member  276 . The first device module  278  and the second device module may be moved together linearly along the rail  276 . The robotic drive  274  also include a third device module  282  and fourth deice module  284  that are each mounted to the rail  276 . The first device module  278  may be disconnected from the second device module  280  and moved to a different position by mounting the first device module  278  to the third device module  282 . The first device module  278  will then move linearly as the third device module  282  move linearly along the rail  276 . 
       FIG. 30  is a block diagram illustrating different positions for a device module in a robotic drive where the device module is mechanically coupled to another device module in accordance with an embodiment. In a first configuration  286 , the first device module  278  is mounted to the second device module  280  and each of the four device modules  278 ,  280 ,  282  and  284  are populated with an elongated medical device. In a second configuration  288 , the first device module  278  is mounted to the third device module  282  and each of the four device modules  278 ,  280 ,  282  and  284  are populated with an elongated medical device. In a third configuration  290 , the first device module  278  is mounted to the third device module  282  and first  278 , third  282  and fourth  284  device modules are populated with an elongated medical device. In the third configuration, the second device module  280  is not populated with an elongated medical device. In a fourth configuration  292 , the first device module  278  is mounted to the fourth device module  284  and first  278 , third  282  and fourth  284  device modules are populated with an elongated medical device. In the fourth configuration, the second device module  280  is not populated with an elongated medical device. In a fifth configuration  294 , the first device module  278  is mounted to the fourth device module  284  and first  278  and fourth  284  device modules are populated with an elongated medical device. In the fifth configuration, the second device module  280  and the third device module  282  are not populated with an elongated medical device. 
     In another embodiment, a device module that is configured to be populated with more than one elongated medical device may be movable between stages on a rail or linear member in a robotic drive.  FIG. 31  is a block diagram illustrating changing the position of a device module in a robotic drive where the device module is configured to be populated with more than one elongated medical device in accordance with an embodiment. In a first configuration  281 , a first device module  285  is coupled to a first stage  291  moveably mounted to a rail or linear member  297 . A second device module  287  is coupled to a second stage  293  moveably mounted to the rail  297 . A third device module  289  is coupled to a third stage  295  moveably mounted to the rail  297 . The first device module  285  and the second device module  287  are each populated with a single elongated medical device, for example, a catheter. The third device module  289  is configured to be populated with two elongated medical devices. In the embodiment of  FIG. 31 , the third device module  289  is populated with a guidewire  277  and a guide catheter  279 . As mentioned, the third device module  289  may be removed from the third stage  295  and moved to a different stage mounted to the rail  297 . In the second configuration  283 , the second device module  287  has been removed from the second stage  293 . In addition, the third device module  289  has been removed from the third stage  295  and coupled to the second stage  293  and is in a position behind the first device module  285 . In the second configuration  283 , a device module is not coupled to the third stage  295 . 
     In various embodiments of a robotic drive (e.g., robotic drive  24  shown in  FIG. 3 ), a device stack-up for a particular procedure my require that a certain device module (e.g., a device module for a guidewire) be located in a particular position, for example, connected to the most proximal stage on the rail or linear member. However, the device stack-up may not require the use of all of the positions in front of the most proximal stage. In order to facilitate configurations with fewer devices, the robotic drive may be configured to allow the nesting of unpopulated drive modules in an unused volume under a cassette either distal or proximal to the unpopulated drive module.  FIG. 32  is a block diagram of a robotic drive including three device modules and a nested unpopulated drive module in accordance with an embodiment. In  FIG. 32 , the robotic drive  300  includes a rail or linear member  302  and a first device module  304  connected to a first stage  324 , a second device module  306  connected to a second stage  326 , an unpopulated drive module  310  connected to a third stage  328  and a third device module  308  connected to a fourth stage  330 . The first device module  304  includes a cassette  312  mounted to a drive module  318 , the second device module  306  includes a cassette  314  mounted to a drive module  320 , and the third device module  308  includes a cassette  316  mounted to a drive module  322 . The unpopulated drive module  310  is positioned (or nested) in an area of overlap with a proximal end of the cassette  314  of the second device module  306 , for example, in an unused volume under the cassette  314 . This allows the unpopulated drive module  310  to be skipped in the device stack-up and an elongated medical device populated in the cassette  316  of the third device module  308  to be fed directly to the second device module  306 . In addition, the third device module  308  may be moved closer to the second device module  306 . In another embodiment, a second drive module may be unpopulated and nested in an area of overlap with a proximal end of a cassette, for example, in the unused volume under the cassette.  FIG. 33  is a block diagram of a robotic drive including two device modules and two nested unpopulated drive modules in accordance with an embodiment. In  FIG. 33 , the cassette from the second device module  306  (shown in  FIG. 32 ) is removed leaving a second unpopulated drive module  348 . In this embodiment, the second unpopulated drive module  348  may be positioned in an area of overlap with the proximal end of cassette  312 , for example, in an unused volume under the cassette  312  of a first device module  304 . The first unpopulated drive module  310  is positioned in area of overlap with the proximal end of cassette  316 , for example, in an unused volume under the cassette  316  of a second device module  346 . This allows the unpopulated drive modules  310  and  348  to be skipped in the device stack-up and an elongated medical device populated in the cassette  316  of the second device module  308  to be fed directly to the first device module  344 . In addition, the second device module  346  may be moved closer to the first device module  344 . 
     To nest unpopulated drive modules, the length of the drive modules may be minimized and the drive modules should be able to get very close to one another. To facilitate the nesting of unpopulated drive modules between device modules, offset brackets may be used to connect a device module or unpopulated drive module to a stage. The offsets created by the offset brackets allow the drive modules to get close enough to nest properly while the length of the stages to which the drive modules are attached does not need to be changed. Referring to  FIGS. 32 and 33 , the first device module  304  is connected to a first offset bracket  336  that defines a first offset  332  between the center of the first stage  324  and the center of the drive module  318  of the first device module  304 . The third device module  308  or the second device module  346  may also be connected to a similar fourth offset bracket  342  to define the first offset  332 . The first unpopulated drive module  310  is connected to a third offset bracket  340  that defines a second offset  334  between the center of the third stage  328  and the center of the unpopulated drive module  310 . The second device module  306  or the second unpopulated drive module  348  may be connected to a similar second offset bracket  338  to define the second offset  334 .  FIG. 34  is a side view of three unpopulated drive modules and offset brackets in accordance with an embodiment and  FIG. 35  is a side rear view of three unpopulated drive modules and offset bracket sin accordance with an embodiment. In  FIGS. 34 and 35 , a first drive module  356  is connected to a first offset bracket  350 , a second drive module  358  is connected to a second offset bracket  352  and a third drive module  360  is connected to a third offset bracket  354 . 
       FIG. 36  is a side view of two device modules and two nested unpopulated drive modules in accordance with an embodiment and  FIG. 37  is an isometric view of a robotic drive with two device modules and two nested unpopulated drive modules in accordance with an embodiment. In  FIGS. 36 and 37 , a first device module  362  includes a cassette  378  mounted to a drive module  371  and second device module  364  includes a cassette  379  mounted to a drive module  373 . The first device module  362  is connected to a first stage  370  and the second device module  364  is connected to a fourth stage  376 . A first unpopulated drive module  366  and a second unpopulated drive module  368  are connected to a second stage  372  and a third stage  374 , respectively, and are located between the first drive module  362  and the second drive module  364  along the rail or linear member. In the embodiment of  FIGS. 36 and 37 , the first unpopulated drive module  366  and the second unpopulated drive module  368  are positioned (or nested) in unused volume under the cassette  378  of the first device module  362 . To facilitate nesting of unpopulated drive modules, each drive module  366 ,  368  and  371  has at least one dimension that is smaller or less than at least one dimension of a cassette (e.g., cassette  378 ) that may be mounted on the drive module. For example, a length of the drive module  366 ,  368 ,  371  as measured from a proximal side to a distal side when the device module  366 ,  368 ,  371  is coupled to the linear member or rail may be smaller or less than a length of the cassette (e.g., cassette  378 ) along a longitudinal axis of the cassette. In some embodiments, the size and dimensions of the drive modules  366 ,  368  and  371  are minimized so that, for example, the drive modules takes up a minimal amount of space along a linear member or rail (e.g., linear member or rail  60  shown in  FIG. 3 ) of the robotic drive when not populated with a cassette. In an embodiment, the unused volume under the cassette  378  is defined by the difference in length between the cassette  378  and the drive module  371  to which the cassette  378  is mounted. As shown in  FIGS. 36 and 37 , the nested unpopulated drive modules  366  and  368  allow the second device module  364  to be brought close to the first device module  362  and, in an embodiment, may eliminate the need for a device support between the second device module  364  and the first device module  362 . 
     The robotic drive may include a crash prevention control system to control how close the cassettes and drive modules can get to one another without making contact. In an embodiment of a robotic drive that includes the ability to nest unpopulated drive modules as described above with respect to  FIGS. 32-37 , the crash prevention control system may be configured to have a first set of parameters for a drive module with a cassette attached and a second set of parameters for a drive module that does not have a cassette attached (i.e., the drive module is unpopulated).  FIG. 38  is a block diagram illustrating a cassette crash prevention apparatus and method in accordance with an embodiment. In  FIG. 38 , a first device module  381  includes a first cassette  383  mounted to a first drive module  385 . The first device module  381  is coupled to a first stage  387  mounted to a rail or linear member  380 . The first device module  381  also includes a cassette proximity sensor  389  and a drive module proximity sensor  390 . The sensors  389 ,  390  are shown positioned on the drive module  385 . In other embodiments, the sensors  389 ,  390  may be positioned on a stage, a cassette, etc. A second device module  382  includes a second cassette  384  mounted to a second drive module  386 . The second device module  382  is coupled to a second stage  388  that is mounted to the rail  380 . A cassette crash stop flag  393  and a module crash stop flag  395  are located in the stage  388 . Alternatively, the crash stop flags  393 ,  395  may be located on the drive module  386 . In an embodiment, the crash stop flags  393 ,  395  are formed from metal and trip the corresponding proximity sensor  389 ,  390 , respectively when moved in front of the proximity sensor. The second device module  382  also includes a cassette presence sensor  391  that may be located, for example, on the second drive module  386 . The cassette presence sensor  391  may be, for example, a reed switch sensor with magnets. If the second cassette  384  is present on the second drive module  386 , the cassette presence sensor  391  may provide a signal indicating the second cassette  384  is mounted on the second drive module  386 . In this instance, the cassette proximity sensor  389  is used to determine if the second cassette  384  is getting too close to the first cassette  383 . In one embodiment, when the second cassette  384  is within a threshold distance of the first cassette  383 , for example, when the cassette crash stop flag  393  moves in front of the proximity sensor  389 , the cassette proximity sensor  389  provides a control signal and an alert may be provided to a user or the movement of the second cassette may be stopped. 
     If the second cassette  384  is not mounted to the second device module  386 , then the drive module proximity sensor  390  is used to determine the location of the second drive module  386  relative to the first drive module  385 .  FIG. 39  is a block diagram illustrating an unpopulated drive module crash prevention apparatus and method in accordance with an embodiment. In  FIG. 39 , a first device module  381  includes a first cassette  383  mounted to a first drive module  385 . The first device module  381  is coupled to a first stage  387  mounted to a rail or linear member  380 . The first drive module  381  also includes a cassette proximity sensor  389  and a drive module proximity sensor  390 . The sensors  389 ,  390  are shown positioned on the drive module  385 . In other embodiments, the sensors  389 ,  390  may be positioned on a stage, a cassette, etc. A second drive module  386  is unpopulated with a cassette and is coupled to the second stage  388  that is mounted to the rail  380 . A cassette crash stop flag  393  and a module crash stop flag  395  are located in the stage  388 . Alternatively, the crash stop flags  393 ,  3905  may be located on the drive module  386 . In an embodiment, the crash stop flags  393 ,  395  are formed from metal and trip the corresponding proximity sensor  389 ,  390 , respectively when moved in front of the proximity sensor. The second drive module  386  also includes a cassette presence sensor  391 . The cassette presence sensor  391  may be, for example, a reed switch sensor with magnets. If a cassette is not present on the second drive module  386 , the cassette presence sensor  391  may provide a signal indicating a cassette is not mounted on the second drive module  386 . In this instance, the drive module proximity sensor  390  is used to determine if the second drive module  386  is getting too close to the first drive module  385 . In one embodiment, when the second drive module  386  is within a threshold distance of the first drive module  385 , for example, when the module crash stop flag  395  moves in front of the proximity sensor  390 , the drive module proximity sensor  390  provides a control signal and an alert may be provided to a user or the movement of the second drive module may be stopped. In another embodiment, if the robotic drive is configured to allow nesting of drive modules, the control computing system may be configured to couple the linear movement of a nested drive module to the linear motion of the device module having the cassette under which the nested drive module is positioned. 
     In another embodiment, a rail or linear member with two slides may be provided to allow certain device modules to be moved past unpopulated drive modules to a different position along the linear member either towards the patient or away from the patient.  FIG. 40  is a front view of a robotic drive with a linear member having two slides in accordance with an embodiment and  FIG. 41  is a perspective view of the robotic drive of  FIG. 40  in accordance with an embodiment. Referring to  FIGS. 40 and 41 , a rail or linear member  400  has a first slide  402  and a second slide  404  configured to be connected to stages and the corresponding device modules or unpopulated drive modules. While the embodiment in  FIGS. 40 and 41  shows a rail with a first slide  402  on an upper surface of the rail and a second slide on the bottom surface of the rail, it should be understood that the slide may be of other opposing surface of the rail. In another embodiment, two separate rails may be used rather than a rail with two slides. A first device module  406  is connected to the first slide  402  of the rail  400  using a stage  416 . A second device module  424  is connected to the second slide  404  of the rail  400  using a second stage  418 . A first unpopulated drive module  408  is connected to the first slide  402  of the rail  400  using a third stage  426 . A second unpopulated drive module  422  is connected to the first slide  402  of the rail  400  using a fourth stage  428 . The unpopulated drive modules  408 ,  422  may be configured to be moved from a vertical to a horizontal position (e.g., “flipped up”). As shown in  FIGS. 40 and 41 , the first unpopulated drive module  408  includes a pivot  410  located on a first end  412  of the first unpopulated drive module  408 . When rotated about the pivot, a second end  414  of the first unpopulated drive module with the coupler  420  moves from a vertical to a horizontal position. In this position, the second drive module  424  may be moved linearly by moving the second stage  418  along the second slide  404  past the “flipped up” drive module  408 . For example, the device module  424  on the second slide  404  may be a dedicated guidewire module and the second slide (or rail) allows the robotic drive to be reconfigured by changing the number of, for example, catheter device modules that are in front of the guidewire module. 
     In another embodiment, a device module may be connected to a second slide on a rail or a second rail and be configured to translate in a manner that allows the device module to be moved past another device module or an unpopulated drive module to a different position.  FIGS. 42A-42D  illustrate a translating device module that may be repositioned along a rail in a robotic drive in accordance with an embodiment.  FIG. 42A  shows a robotic drive  430  that includes a first device module  432  connected to a first slide (e.g., first slide  402  shown in  FIG. 40 ) of a rail or linear member  438  using a first stage  440 , a second device module  434  connected to the first slide of the rail  438  using a second stage  442  and a third device module  436  connected to a second slide (e.g., second slide  404  shown in  FIG. 40 ) of the rail  438  using a third stage  443 . The third device module  436  includes an extension member  444  as shown in  FIG. 42B  that can be pulled out away from the rail  438  so that the device module  436  is able to pass the other device modules  432  and  434  (or alternatively, unpopulated drive modules) on the first slide of the rail  438 . The third drive module  436  may then be moved linearly by moving the third stage along the second slide of the rail  438  to a position past the second device module  434  as shown in  FIG. 42C . In  FIG. 42D , when the third device module  436  is in the desired position, the extension member  444  may be moved back towards the rail  438 . 
     As discussed above, in one embodiment a cassette used in a device module (e.g., cassette  91  shown in  FIG. 7 ) may be configured to provide one degree of freedom (e.g., rotation). Accordingly, a drive module with a single coupler (e.g., drive module  68  shown in  FIG. 5 ) may be used to drive the single degree of freedom of the cassette. In another embodiment, a cassette used in a device module (e.g., cassette  111  shown in  FIG. 9 ) may be configured to provide two or more degrees of freedom (e.g., rotation and pinch/unpinch for a guidewire). Accordingly, a drive module may be configured to include two or more couplers to support cassettes that provide one or more degrees of freedom. In an embodiment, the drive module with two or more couplers includes a separate motor for each coupler.  FIG. 43  is a top view of a portion of robotic drive in a tri-axial configuration and including drive modules with more than one coupler in accordance with an embodiment. As mentioned above, as used herein the terms tri-axial, bi-axial and mono-axial refer to the number of serially concentric catheters but not including any wire based EMDs. In  FIG. 43 , a first drive module  450 , a second drive module  452 , a third drive module  454 , and a fourth drive module  456  are shown. A cassette  458 ,  460 ,  462  and  464  is mounted to each drive module  450 ,  452 ,  454  and  456 , respectively. Cassettes  458 ,  460 ,  462  are configured to provide one degree of freedom and the fourth cassette  464  is configured to provide two degrees of freedom. Each of the four drive modules include two couplers as shown in  FIGS. 44 and 45 .  FIG. 44  is a top view of a portion of a robotic drive in a bi-axial configuration and including drive modules with more than one coupler in accordance with an embodiment and  FIG. 45  is a top view of a portion of a robotic drive in a mono-axial configuration and including drive modules with more than one coupler in accordance with an embodiment. In  FIG. 44 , the fourth drive module  456  is unpopulated and in  FIG. 45 , the third  454  and fourth  456  drive module are unpopulated. In  FIG. 44 , unpopulated drive module  456  includes a first coupler  466  and a second coupler  468 . A separate motor (not shown) may be provided in the drive module  456  to drive each coupler  466 ,  468 . The first coupler  466  and the second coupler  468  are aligned along a device axis (not shown) which enables being put into a grid/matrix. Each drive module  450 ,  452 ,  454  and  456  may be used to couple to a cassette with one or two degrees of freedom. For example, in  FIG. 44  the second drive module  452  is coupled to a cassette  460  with a single degree of freedom and in  FIG. 45 , the second drive module  452  is coupled to a cassette with two degrees of freedom. Each drive module  450 ,  452 ,  454  and  456  uses a separate stage translation motor to drive linear movement of the respective drive module along a rail or linear member. 
       FIG. 46  is a side view of a cassette with one degree of freedom mounted to a drive module with more than one coupler in accordance with an embodiment. In  FIG. 46 , a cassette  476  with a single degree of freedom mounts to a drive module  470  using a first coupler (not shown) and the second coupler  474  remains unpopulated and does not engage with the cassette  476 . In an embodiment, the control computing system of the robotic drive may be configured to automatically lock-out the unused coupler  474 . In one example, a sensor may be provided in the drive module  470  that can detect what type of cassette is mounted to the drive module. In another example, a user may enter the type of cassette using, for example, a control station. In another embodiment, a robotic drive may include a combination of drive modules with a single coupler and drive modules with two or more couplers.  FIG. 47  is a top view of a portion of a robotic drive in a tri-axial configuration and including both drive modules with a single coupler and drive modules with more than one coupler in accordance with an embodiment.  FIG. 47  shows three drive modules  478 ,  480  and  482  with a single coupler and one drive module  484  with two couplers. Cassettes  486 ,  488  and  490  with a single degree of freedom are mounted to the drive modules  478 ,  480  and  482 , respectively. A cassette  492  with two degrees of freedom is mounted to the drive module  484  with two couplers. Having a robotic drive system that includes drive modules with two or more couplers provide the ability to reconfigure the robotic drive by only moving cassettes between drive modules. 
     In another embodiment, a cassette that is configured to provide two or more degrees of freedom (e.g., rotation and pinch/unpinch for a guidewire) may be mounted on two independently driven drive modules, in other words, the cassette may straddle between two drive modules engaging a coupler on each drive module. Accordingly, two drive modules may be used to manipulate elongated medical device that require more complex degrees of freedom.  FIG. 48  is a top view of a portion of a robotic drive in a bi-axial configuration and includes a cassette mounted to two drive modules in accordance with an embodiment and  FIG. 49  is a top view of a portion of a robotic drive in mono-axial configuration and includes a cassette mounted to two drive modules in accordance with an embodiment. In  FIG. 48 , a first drive module  500 , a second drive module  502  and a third drive module  504  are provided that each have a single coupler and are connected to a first  510 , second  512  and third  514  stage, respectively. A fourth drive module  506  includes two couplers as described above with respect to  FIGS. 43-47  and is connected to a fourth stage  516 . While the fourth drive module  506  is shown as having two couplers, the fourth drive module could also be a single coupler drive module similar to drive modules  500 - 504 . A cassette  508  that is configured to provide two degrees of freedom is mounted so as to engage both the coupler the third drive module  504  and one of the couplers of the fourth drive module  506 . For example, cassette  508  may be configured to provide rotation and to pinch/unpinch the elongated medical device. Linear movement of the elongated medical device is provide by linear movement of the third  504  and fourth  506  drive modules via the third  514  and fourth  516  stages along a rail or linear member. Each coupler can provide power to drive one of the degrees of freedom for the cassette  508 . The third drive module  504  and the fourth drive module are positioned a predetermined distance from one another that allows the cassette to be mounted on each drive module  504 ,  506 . The control computing system (not shown) of the robotic drive may be configured to linearly translate the third drive module  504  and the fourth drive module  506  as a unit so that the relative distance between the couplers on each drive module  504 ,  506  remains the same. For example, the third  504  and fourth  506  drive modules are electronically coupled to effectively form a single drive module. In another embodiment, the cassette may be mounted to two single coupler drive modules. In  FIG. 49 , the cassette  508  is mounted so as to engage the coupler of the second drive module  502  and the coupler of the third drive module  504 . In another embodiment, two independent drive modules may be mechanically coupled together and connect to a single stage so that a single stage translation motor may be used to drive the mechanically coupled pair of drive modules. This may be used, for example, to reduce the number of catheters in front of device module with a cassette that provide two or more degrees of freedom. Straddling drives can also be used for single devices that require relative linear translation. For example, some self-expanding stents or coils may require pulling on a wire or shaft to deploy. Two modules may be utilized where one modules holds onto the body or sheath of the deployment device while the other module handles the deployment wire or shaft. 
     As discussed above, the robotic drive may be reconfigured to provide various serial device configurations. In other embodiments, various apparatus and methods may be used to provide a robotic drive with both serial and parallel device configurations.  FIG. 50  is a block diagram of a parallel configuration for elongated medical devices in a robotic drive in accordance with an embodiment. The robotic drive configuration  520  includes a first device module  522 , a second device module  524  and a third device module  526  connected to a rail or linear drive module  528  using a first stage  530 , a second stage  532  and a third stage  534 , respectively. The first device module  522  includes a first elongated medical device (EMD)  536 , the second device modules  524  includes a second EMD  538  and the third device module  526  includes a third EMD  540 . The first EMD  536  is supported by a first support track  542  and is configured to receive the second  538  and third  540  EMDs in a parallel configuration. The second EMD  538  and the third EMD  540  are supported between the second device module  524  and the first device module  522  using a second support track  544 . The third EMD  540  is supported between the third device module  526  and the second device module  524  with a third support track  546 . In an embodiment, the first  542 , second  544 , and third  546  support tracks may be a device support as described further below with respect to  FIGS. 79-107 . Rather than enter a hub of the second device module  524  and pass through the second EMD  538  in a serial configuration, the third EMD  540  is positioned in a bypass channel (shown in  FIGS. 51 and 52 ) on a cassette of the second device module  524  so as to bypass the hub and enter the second support track  544  parallel to the second EMD  538 . The second  538  and third  540  EMDs then enter a hub  548  of the first EMD  536  on the first device module  522 . The second  538  and third  540  EMDs may then enter and pass through the first EMD  536  in a parallel configuration. As mentioned, a cassette in the second device module  524  includes a bypass channel to support the third EMD  540  as it bypasses the second EMD  538 .  FIG. 51  is a top view of a cassette with a bypass channel and elongated medical devices in a serial configuration in accordance with an embodiment and  FIG. 52  is a top view of a cassette with a bypass channel and elongated medical devices in a parallel configuration in accordance with an embodiment. Referring to  FIGS. 51 and 52 , a cassette  550  incudes a bypass channel  554  and a bypass channel connection point  564 . The cassette  550  includes a first EMD  558  and a first support track  552 . In  FIG. 51 , a second EMD  560  is shown that is supported by a second support track  556  that connects to a hub  562  so that the second EMD may enter the hub  562  and pass through the first EMD  558  in a serial configuration. In an embodiment, the first  552  and second  556  support tracks may be a device support as described further below with respect to  FIGS. 79-107 . In  FIG. 52 , to provide a parallel device configuration, the second support track  556  connects to the connection point  564  so that the second EMD  560  may be positioned in and move along the bypass channel  554 . The first support track  552  is configured to receive the second EMD  560  at the distal end of the bypass channel  554  so that the second EMD  560  travels through the second support track  552  parallel to the first EMD  558 . In the embodiment shown in  FIG. 52 , the first EMD  558  is a catheter that is positioned along a central axis of the cassette  550  and the second EMD  560  is a wire-based device (e.g., a guidewire). In another embodiment, the first EMD  558  may be a wire-based device that is positioned along the central axis of the cassette  550  and the second EMD  560  may be a catheter (e.g., a rapid exchange catheter). 
     In another embodiment, a support track may be used to support an elongated medical device as it bypasses a hub to provide a parallel device configuration.  FIG. 53  is a block diagram of a parallel configuration for elongated medical devices in a robotic drive in accordance with an embodiment. The robotic drive configuration  521  includes a first device module  523 , a second device module  525  and a third device module  527  connected to a rail or linear member  529  using a first stage  531 , a second stage  533  and a third stage  535 , respectively. The first device module  523  includes a first elongated medical device (EMD)  537 , the second device modules  525  includes a second EMD  539  and the third device module  527  includes a third EMD  541 . The first EMD  537  is supported by a first support track  543  and is configured to receive the second  539  and third  541  EMDs in a parallel configuration. The second EMD  539  is supported between the second device module  525  and the first device module  523  with a second support track  545 . In an embodiment, the first  542  and second  545  support tracks may be a device support as described further below with respect to  FIGS. 79-107 . The second support track connects to a hub adapter  549  in the first device module  523 . The third EMD  541  is supported between the third device module  527  and the first device module  523  using a third support track  547 . Rather than enter a hub of the second device module  525  and pass through the second EMD  539  in a serial configuration, the third EMD  541  and the third support track  547  are positioned so as to bypass the hub. The third support track  547  is connected to the hub adapter  549 . The second EMD  539  and the third EMD  541  enter the hub adapter  549  and then a hub  551  of the first EMD  537  in a parallel configuration. The second  539  and the third  541  EMDs may then enter and pass through the first EMD  537  in a parallel to one another. The hub adapter  549  is configured to connect to and receive two or more support tracks.  FIG. 54  is a top view of a cassette configured to receive two elongated medical devices in a parallel configuration in accordance with an embodiment. A cassette  553  incudes a first EMD  561  and a first support track  555 . A second EMD  563  is shown that is supported by a second support track  557  that connects to a hub adapter  567 . A third EMD  565  is shown that is supported by a third support track  559  that connects to the hub adapter  567 . Accordingly, the hub adapter  567  is configured to connect to the second support track  557  and the third support track  559  so that the second EMD  563  and the third EMD  565  may enter the hub  569  and pass through the first EMD  555  in a parallel configuration. 
     In another embodiment, a parallel device configuration may be facilitated by providing multiple couplers on each drive module so as to provide multiple device axis in the robotic drive.  FIG. 55  is a block diagram of a robotic drive configuration with multiple device axes in accordance with an embodiment. A first drive module  570 , a second drive module  572 , a third drive module  574 , a fourth drive module  576  and a fifth drive module  578  are connected to a rail or linear member  580  using a first stage  582 , a second stage  584 , a third stage  586 , a fourth stage  588  and a fifth stage  589 , respectively. Each drive module includes two couplers  593 . The two couplers  593  on each drive module  570 ,  572 ,  574 ,  576 ,  578  are positioned parallel to one another such that each coupler defines a device axis. A first device axis  591  is defined by a first coupler on each drive module  570 ,  572 ,  574 ,  576 ,  587  and a second device axis  592  is defined by a second coupler on each drive module  570 ,  572 ,  574 ,  576 ,  587 . In  FIG. 55 , the couplers on fourth  576  and fifth  578  drive modules are unpopulated. A first cassette  590  is mounted to the first drive module  570  and includes a first EMD (not shown) supported in a first support track  596 . A second cassette  594  is mounted to a coupler  593  on the first device axis  591  and includes a second EMD  597  that is supported by a second support track  571  between the second drive module  572  and the first drive module  570 . The second coupler on the second drive module  572  that is on the second device axis  592  is unpopulated. A third cassette  595  is mounted to a coupler  593  on the second device axis  592  and includes a third EMD  599  that is supported by a third support track  573  between the second drive module  572  and the first drive module  570 . In an embodiment, the first  596 , second  571  and third  573  support tracks may be a device support as described further below with respect to  FIGS. 79-107 . The second coupler on the third drive module  574  that is on the first device axis  591  is unpopulated. The second support track  571  and the third support track  573  each connect a hub adapter  598  (e.g., a hub adapter as described above with respect to  FIG. 54 ). The second EMD  597  and the third EMD  599  enter the hub adapter  598  and then a hub  575  of the first EMD in a parallel configuration. In other embodiments, additional cassettes and EMDs in the fourth  576  and fifth  578  drive modules may be provided in either a serial or parallel configuration. 
     In another embodiment, an EMD that includes a deployable portion may be positioned across two device modules and the independent linear motion of the device modules used to deploy the EMD. For example, a self-expanding stent or coil may requiring pulling on a wire or a shaft or knob to deploy.  FIG. 56  is a top view of an elongated medical device positioned across two device modules in a first position in accordance with an embodiment. A first device module  600  is connected to a rail or linear member  604  using a first stage  606  and a second device module  602  is connected to the rail  604  using a second stage  608 . A first linear translation motor  624  is coupled to the first stage  606  and is configured move the first stage  606  and the first device module  600  linearly along the rail  604 . A second linear translation motor  626  is coupled to the second stage  608  and is configured move the second stage  608  and the second device module  602  linearly along the rail  604 . A linearly deployable EMD includes a first section  610  positioned in the first device module  600  and a second section  612  positioned in the second device module  604 . The first section  610  may be for example, a body or sheath of the linearly deployable EMD and the second section  612  may be, for example, a deployment wire and/or a deployment shaft or knob. The linear movement, e.g., indicated by arrow  616 , of the first  600  and second  602  device modules may be coupled together so that the two modules move together from a first position  614  (shown in  FIG. 57 ) to a second position  618  (shown in  FIG. 58 ) to linearly translate the deployable EMD.  FIG. 57  is a top view of an elongated medical device positioned across two device modules in a second position in accordance with an embodiment. In  FIG. 57 , the first  600  and second  602  drive modules have been moved together in a distal direction by coupling the linear motion of the first  606  and second  608  stages along the rail or linear member  604 . To deploy the linearly deployable EMD, the second stage  608  and the second device module  602  may be moved independently using the second stage translation motor  626 .  FIG. 58  is a top view of an elongated medical device positioned across two device modules in a third position in accordance with an embodiment. In  FIG. 58 , the second stage  608  and the second device module  602  have been moved away from the first stage  606  and first device module  600  in a proximal direction as indicated by arrow  620 . The second device module  602  with the second section  612  of the EMD is shown in a third position  622 . Linear movement of the second device module  602  provides the required linear motion (e.g., pulling) on the second section  612  of the EMD to deploy the device. 
     In another embodiment, a coupler in a drive module of a device module may be used to deploy a rotationally deployable EMD. For example, a stent system may include a shaft or knob to retract a sheath over a self-expanding stent. A rotating motion may be used to accomplish the unsheathing.  FIG. 59  is a perspective view of an exemplary rotationally deployable elongated medical device with an on-device adapter in accordance with an embodiment. A rotationally deployable EMD  630  includes a shaft or knob  632  that may be rotated to deploy, for example, a stent. An on-device adapter  634 , for example, a gear, is provided around the shaft to interface with a cassette in a device module of a robotic drive.  FIG. 60  is cross-sectional view of the rotationally deployable EMD of  FIG. 59  in an un-deployed state in accordance with an embodiment,  FIG. 61  is cross-sectional view of the rotationally deployable EMD of  FIG. 59  in a deployed state in accordance with an embodiment and  FIG. 62  is a cross-sectional vie of the rotationally deployable EMD of  FIG. 59  in a cassette on a drive module in accordance with an embodiment. The shaft  632  includes a deployable element  636  that is shown in  FIG. 60  in a first position  638  where the device  630  is not deployed. The deployment element  636  may be, for example, a screw mechanism. The on-device adapter  634  may be used to interface with a bevel gear  648  in a cassette  646  as shown in  FIG. 62 . The bevel gear is coupled to a coupler  642  in a drive module  644  to which the cassette  646  is mounted. Rotation of the coupler  642  rotates the bevel gear  648  which in turn rotates the on-device adapter  634 . Rotation of the on-device adapter  634  causes the shaft  632  to rotate which translates the deployment element  636  linearly to a second position  640  as shown in  FIG. 61 , which causes the deployment (e.g., unsheathing) of the device  630 . 
     In another embodiment, a parallel device layout may be provided by using a parking clamp that is mounted to a frame of the robotic drive or moveably mounted to the rail or linear member of the robotic drive.  FIG. 63  is a block diagram of a parallel device configuration using a global parking clamp in accordance with an embodiment. A global parking clamp  662  is mounted to a frame  652  of the robotic drive which includes a first device module  654  and as second device module  656 . The first device module  654  is connected to a rail or linear member  650  using a first stage  658  and the second device module is connected to the rail  650  using a second stage  660 . The first device module includes a first EMD  664  that is configured to receive a second EMD  666  that is included in the second device module  656  and a third EMD  668  that is held by the global parking clamp  662 . The global parking clamp  662  may be configured, for example, to fix the third EMD  668  relative to a patient (not shown). The clamp  662  allows the other modules  654 ,  656  to move linearly while holding the clamped third EMD  668  fixed relative to the patient. The second  666  and third  668  EMD enter the first EMD  664  parallel to one another. In another embodiment, the global parking clamp may be movable.  FIG. 64  is a perspective view of a moveable global parking clamp in accordance with an embodiment. In  FIG. 64 , a device module  672  is connected to a first rail or linear member  670  using a first stage  678 . A global parking clamp  674  is coupled to a second rail  682  using a mounting bracket  676  connected to a second stage  680  that is mounted to the second rail  682 . Accordingly, the global parking clamp  674  may be moved by linearly translating the second stage  680  along the second rail  682  either manually or robotically with a stage translation motor (not shown). As mentioned, the global parking clamp  674  may be used to hold an EMD (not shown) that may be provided in a parallel configuration. 
     A parking clamp may also be provided directly on a cassette to facilitate a parallel device configuration.  FIG. 65  is top view of a device module including a cassette with a module parking clamp in accordance with embodiment. In  FIG. 65 , a device module  690  includes a cassette  692  mounted to a drive module  694 . A module parking clamp  698  is mounted to a proximal end  696  of the cassette  692 . Accordingly, the parking clamp  698  is fixed relative to an EMD (not shown) that is inserted into the clamp  698  and held by the clamp  698 . The EMD held by the clamp  7698  may be positioned so as to enter the hub  691  if the EMD positioned in the cassette parallel to another EMD that is in a serial configuration with hub  691 . Linear movement of the device module  690  may be may be used to move the EMD in the clamp  698  when the clamp  698  is active to adjust the position of the clamped EMD. The clamp  698  may be manually or robotically actuated. In one embodiment, the clamp  698  may be used to hold the deployment wire for a self-deploying stent. In another embodiment, the clamp may be used to park a balloon for a balloon assisted coiling. 
     In another embodiment, a parallel device configuration may be provided by using a cassette that is configured to provide a linear degree of freedom for a rapid exchange elongated medical device, such as for example, a rapid exchange balloon.  FIG. 66  is a top view of a device module including a cassette with a rapid exchange tire drive in accordance with an embodiment. Device module  700  includes a cassette  702  mounted to a drive module  704 . In an embodiment, the drive module  704  may include an auxiliary encoder (not shown) that may be used to measure movement of an EMD. The cassette  702  includes a first tire  706  and a second tire  708  on opposite sides of a channel  710 . An EMD (not shown) may be positioned in the channel  710 . The pair of tires  706 , 708  may be used to provide linear motion to an EMD positioned in the channel  710 . The channel  710  is used to direct the EMD begin driven by the tires  706 ,  708  into the more distal hub of a distal EMD (not shown) it is being driven into. Tires  706  and  708  may be connected to a coupler (shown in  FIGS. 67 and 68 ) of a drive module  704  to receive power to drive the EMD. Accordingly, the cassette  702  is configured to repurpose a coupler that is normally used for a rotary degree of freedom and use it for a linear degree of freedom with a tire drive formed by the pair of tires  706  and  708 . 
       FIG. 67  is a perspective view of a drive mechanism and interface between a drive module and the rapid exchange tire drive in accordance with an embodiment and  FIG. 68  is a perspective view of a drive mechanism and interface between a drive module and the rapid exchange tire drive in accordance with an embodiment. Referring to  FIGS. 67 and 68 , the cassette  702  is configured to interface with a coupler  712  (i.e., a rotary power interface) of the drive module  704  and transform the rotary motion into translational motion via a tire drive (e.g., tires  706  and  708  shown in  FIGS. 66 and 68 ). Cassette  702  includes a gear assembly  714  to interface with the coupler  712 . When the cassette  702  is mounted to the drive module  704 , the coupler  712  is coupled to a first gear  716  of the gear assembly  714  in the bottom surface of the cassette  702 . The first gear is in contact with a second gear  718  which is used to rotate the second tire  708  and the second gear is on contact with a third gear  720  which is used to rotate the first tire  706 . The first  706  and second  708  tires are positioned on the cassette  702  offset from the rotational axis of the coupler  712 , allowing the tires  706 ,  708  to be away from the central device longitudinal axis. The gear assembly  714  also includes a manual unpinch arm  722  that may be used to unclamp the tires  706  and  708  to facilitate loading and unloading of an EMD. The manual unpinch arm  722  is used to separate the tires  706 , 708  to all an EMD to be unloaded from the drive. When the unpinch lever  722  is not actuated, it may also clamp the EMD at a certain force between the tires  706 ,  708  via a spring (not shown). In an embodiment, the force can be adjusted to increase or decrease the clamped driving force. For example, the adjustment mechanism may be a screw that changes the compressed length of the spring. Rotation of the coupler  712  causes rotation of the first gear  716  which in turn rotates the second gear  718  which in turn causes rotation of the third gear  720 . Accordingly, the first tire  706  and the second tire  708  may be rotated so as to cause linear motion of an EMD in the channel  710  (shown in  FIG. 66 ). In an embodiment, the EMD positioned in the channel  710  and driven by tires  706  and  708  is a rapid exchange EMD such as, for example, a rapid exchange catheter or a rapid exchange balloon. In an embodiment, the drive module  704  may include a sensor to detect when a rapid exchange cassette  702  is mounted to the drive module. 
       FIG. 69  is an exemplary robotic drive device module configuration including a rapid exchange tire drive in accordance with an embodiment. The configuration shown in  FIG. 69  includes a first drive module  724 , a second device module  726 , a third device module  728  and a fourth device module  730 . The third device module  728  includes a rapid exchange cassette  732  (for example, cassette  702  described above with respect to  FIG. 66 ) to provide an EMD in parallel in addition to the EMDS that may be provided in a serial in the first  724 , second  726  and fourth  730  device modules. The third device module  728  with rapid exchange cassette  732  (including the tire drive) may be positioned directly behind second device module  726  and, therefore, directly behind a y-connector on the second drive module  726 . Accordingly, the tire drive will not interfere with the more proximal EMDs. In addition, the configuration may allow for reducing more proximal EMDs loss of working length by allowing the more proximal EMDs to get closer to the more distal hub. The ability to position the third device module  728  directly behind the second device module  726  may eliminate the need for a support track (or device support) between the second  726  and third  728  device modules. The second  726  and third  728  device modules may be coupled mechanically or electronically so that they move together linearly. In other embodiments, a rapid exchange cassette  732  may be provided in a different position in the order of device modules in a robotic drive, for example, the rapid exchange cassette may be utilized on the second device module  726  and a non-rapid exchange cassette in the third device module  728 . In this example, the fourth device module  730  may remain unpopulated. The rapid exchange cassette  732  may also be removed from the robotic drive if not needed for a particular case. The ability to utilize a tire drive (i.e., shaft driving) for linear translation of an EMD that requires only the linear degree of freedom rather than hub driving the single degree of freedom EMD may have several advantages such as full manipulation over the entire EMD range once inside a Y-connector, faster traverse speeds with no resets (continuous motion), and eliminating the need for device support tracks. 
       FIG. 70  is a block diagram of a robotic drive configuration including a dedicated guidewire and rapid exchange catheter device module in accordance with an embodiment. The configuration in  FIG. 70  includes a first device module  740  and a second device module  742  coupled to a rail or linear member  746  using a first stage  748  and a second stage  750 , respectively. In addition, the most proximal device module  744  is a dedicated guidewire and rapid exchange catheter device module. The guidewire and rapid exchange catheter device module  744  is coupled to the rail  746  using a third stage  752 . The guidewire and rapid exchange catheter device module  744  incudes a cassette  745  that is configured to provide linear translation to a rapid exchange catheter  758  using, for example, tires  754  and to provide rotation and linear translation for a guidewire  756 . The guidewire  756  and rapid exchange catheter  758  move in parallel through an EMD distal to the guidewire and rapid exchange catheter deice module  744 . In  FIG. 70 , the first device module  740  and the second device modules  742  may include catheters configured to receive the guidewire  756  and rapid exchange catheter  758 . Accordingly, in this configuration multiple catheters may be provided in front (i.e., distal to) the guidewire and rapid exchange catheter drive. 
     In another embodiment, a robotic drive may include multiple parallel rails or linear members that enable device modules to move past one another and that is designed to facilitate reconfiguring the device modules between serial and parallel configurations.  FIG. 71  is a top view of a robotic drive with multiple parallel rails in accordance with embodiment. The robotic drive  760  includes a first rail or linear member  762 , a second rail or linear member  764  and a third rail or linear member  766  that are positioned parallel to one another. A first device module  768  is coupled to the first rail  762  using a first stage  780 . A first stage translation motor  774  is used to drive the first stage  780  linearly along the first rail  762 . A second device module  770  is coupled to the second rail  764  using a second stage  784 . A second stage translation motor  776  is used to drive the second stage  784  linearly along the second rail  764 . A third device module  772  is coupled to the third rail  766  using a third stage  785  (shown in  FIGS. 75 and 77 ). A third stage translation motor  778  is used to drive the third stage  785  linearly along the third rail  766 . A first position offset slide  782  is mounted to the first stage  780  and may be used to adjust the position of the first device module  768  relative to the first  762 , second  764  and third  766  rails. A second position offset slide  786  is mounted to the second stage  784  and may be used to adjust the position of the second device module  770  relative to the first  762 , second  764  and third rails. A third position offset slide (not shown) may also be mounted to the third stage  785  (shown in  FIGS. 75 and 77 ) for adjusting the position of the third device module  772 . When each device module  768 ,  770  and  772  are in a position where they are aligned over the respective rail  762 ,  764 ,  766  to which they are attached, each device module  768 ,  770   772  may be moved linearly and may move past one another along their respective rails. In addition, the position of the first device module  768 , second device module  770  and third device module  772  may be adjusted so that the various device modules are aligned in a serial or parallel configuration for driving EMDs (EMDs not shown). In  FIG. 71 , the first device module  768  has been moved along the first position offset slide  782  to a position over a first gap  788  between the first  762  and third  766  rails. The second device module  770  has been moved along the second position offset slide  786  to a position over a second gap  790  between the second  764  and third  766  rails. A device module may be moved along a position offset slide either manually or robotically. 
       FIG. 72  is a sectioned view of a device module with a position offset slide and the device module in a first position in accordance with an embodiment and  FIG. 73  is a sectioned view of a device module with a position offset slide and the device module in a second position in accordance with an embodiment. The first device module  768  includes a cassette  769  mounted to a drive module  771 . The drive module  771  is mounted to the first position offset slide  782  which is mounted to the first stage  780  which is connected to the first rail  762 . The first device module  768  is shown in a first position  761  where the first device module  768  is positioned over the first rail  762 . The first device module  768  may be moved along the first position offset slide  782  from the first position to a second position  763  shown in  FIG. 73 . The first device module  768  is moved in a direction (indicated by arrow  765 ) towards the third rail  766 . In the second position  763 , the first device module  768  is in a position over the third rail  766 . In an embodiment, the drive module may include a sprung plunger  773  and the sprung plunger  773  may be used to lock the position of the device module  768  along the first position offset slide  782 . For example, the sprung plunger  773  may be positioned in one of the holes  781  in the first position offset slide  782  to secure it in place so as to prevent the device module  768  from moving from, for example, the second position  763 . In other embodiments, the first device module  768  may be moved along the first position offset slide  782  until it is in a position over the second rail  764 . The positions of the other device modules may also be adjusted to provide different configurations as discussed below. 
       FIG. 74  is a top view of device modules in an exemplary serial configuration in a multiple rail robotic drive in accordance with an embodiment. The first  768 , second  770  and third  772  device modules are in a serial configuration with each device module positioned over the third rail  766 . The first device module  768  is positioned along the first rail  762  and along the first position offset slide  782  so that it is located behind the third device module  772 . The second device module  770  is positioned along the second rail  764  and along the second position offset slide  786  so that it is located behind the first device module  768 . In the serial configuration of  FIG. 74 , the device axis of each device module  768 ,  770  and  772  are aligned.  FIG. 75  is a perspective view of device modules in an exemplary serial configuration in a multiple rail robotic drive in accordance with an embodiment. In  FIG. 75 , the first  768 , second  770  and third  770  device modules are in a serial configuration with each device module positioned over a gap  788  between the first  762  and third  766  rails. The first device module  768  is positioned along the first rail  762  and along the first position offset slide  782  so that it is located behind the third device module  772 . The second device module  772  is positioned along the second rail  764  and along the second position offset slide  786  so that it is located behind the first device module  768 . In the serial configuration of  FIG. 75 , the device axis of each device module  768 ,  770  and  772  are aligned. 
       FIG. 76  is a top view of device modules in an exemplary parallel configuration in a multiple rail robotic drive in accordance with an embodiment. The first  768  and second  770  device modules are in a parallel configuration. The first device module  768  is positioned over a gap  788  between the first  762  and third  766  rails and the second device module  770  is positioned over a gap  790  between the second  764  and third  766  rails. The third device module  772  is positioned over the third rail  766  and is located along the third rail  766  at a position in front of the first  768  and second  770  device modules. The first device module  768  is positioned along the first rail  762  and along the first position offset slide  782  so that it is located behind the third device module  772  and over the gap  788 . The second device module  770  is positioned along the second rail  764  and along the second position offset slide  786  so that it is located behind the first device module  768  and over gap  790 . In configuration of  FIG. 76 , the EMD (not shown) in the first device module  768  and the EMD (not shown) in the second device module  770  would enter the hub of the third device module  772  in parallel.  FIG. 77  is a perspective view of device modules in an exemplary parallel configuration in a multiple rail robotic drive in accordance with an embodiment. The first  768  and second  770  device modules are in a parallel configuration. The first device module  768  positioned over the first rail  762  and the second device module  770  positioned over the third rail  766 . The third device module  772  is positioned over the gap  788  between the first  762  and third  766  rails and is located along the third rail  766  at a position in front of the first  768  and second  770  device modules. The first device module  768  is positioned along the first rail  762  and along the first position offset slide  782  so that it is located behind the third device module  772  and over the first rail  762 . The second device module  770  is positioned along the second rail  764  and along the second position offset slide  786  so that it is located behind the first device module  768  and over the third rail  766 . In configuration of  FIG. 77 , the EMD (not shown) in the first device module  768  and the EMD (not shown) in the second device module  770  would enter the hub of the third device module  772  in parallel. 
     In another embodiment, the position of device modules may be performed using a positioning system such as, for example, a robotic arm.  FIGS. 78A-C  illustrate reconfiguring device module positions using a positioning system in accordance with an embodiment. In  FIG. 78A , a first device module  794  is in a fixed position. A positioning system,  792 , for example, a robotic arm, is connected to a second device module  796  and is operated to move and hold the second device module  796  in a parallel configuration. The robotic arm  792  may be used to move the second device module  796  to a serial configuration as shown in  FIG. 78B . In  FIG. 78C , the robotic arm  792  may further be used to linearly translate the second device module  796 . In other embodiment, two or more robotic arms may be provided that are each connected to a device module and used to move and reconfigure the position of the respective drive module with respect to the other drive modules. In this embodiment, the device modules are not attached to a rail or linear member and are instead acting as the arm&#39;s end effector. For a serial configuration, the arms align the device modules to follow a line or other trajectory, which could include a curved path that avoids patient interference. For a parallel configuration, the arms align selected modules in a parallel configuration, allowing the proximal hubs to pass one another. 
     As mentioned above with respect to  FIG. 3 , the robotic drive  24  may include a device support  79   a - d  between each device module  32   a - d  and between the most distal device module  32   a  and the device support connection  72 . Each device support  79   a - d  is configured to prevent elongated medical devices from buckling as they are advanced outside of a patient and prior to being advanced into a more distal EMD. In an embodiment, each device support  79   a - d  may be a flexible tube with a lengthwise slit and is used in conjunction with a splitter on a cassette. Each device support  79   a - d  is fixed or constrained at both ends so that the device support may be kept in tension so that the flexible tube is limited in the amount of displacement it can buckle under a compressive load. Buckling the EMD limits the amount of force that can be applied and can permanently damage the elongated medical device. The compressive load can be caused by several factors, which may include friction between the EMD and device support, friction between the device support and a cassette (e.g., a splitter in the cassette (discussed below with respect to  FIGS. 102-104 )), etc. Maintaining the device support under tension may eliminate the need for extra column strength and allow for smaller, more flexible device supports. In one embodiment where the device support is a flexible tube, tension may be provided by fixing a front (or distal) and rear (or proximal) point (or location) of the flexible tube. The device supports  79   a - d  shown in  FIG. 3  are one embodiment of a device support with fixed front (or distal) and rear (or proximal) points (or locations). In another embodiment, the device support may be an accordion or spring type support that provides appropriate tension. Each of these different embodiments of a device support are discussed further below. 
       FIG. 79  is a perspective view of device supports with fixed front (or distal) and rear (or proximal) points to provide appropriate tension in accordance with an embodiment.  FIG. 79  illustrates the device support embodiment shown in  FIG. 3 . In  FIG. 79 , a first device module  802  includes a first cassette  806  that has a first device support  828 , e.g., a flexible tube, positioned in a channel  824  of the cassette  802 . The first cassette  806  and the first device support  828  are moveable relative to one another. In  FIG. 79 , the first device support  828  extends out from the distal end of the first cassette  806  and a first end of the first device support  828  connects to a proximal end of a second device module  804  at a first front (or distal) fixed point  810 . The second device module  804  is located distal to the first device module  802 . The second device module  804  includes a second cassette  808  and a support arm  816  that extends from the second device module  804  in a proximal direction towards the first cassette  806 . A second end of the first device support  828  extends out from the proximal end of the first cassette  806  and connects to a first rear (or proximal) fixed point  812  on a proximal end of the support arm  816  of the second device module. The first device support  828  is held in place by fixed first front  810  and first rear  812  points. The first front and rear fixed points  810  and  812  are kept a constant distance from one another. The first front and rear fixed points  810  and  812  may be rigid or may have some elasticity to account for manufacturing and assembly tolerance. The first device module  802  also includes a support arm  814  that may be used to provide a rear (or proximal) fixed point for a device support for a cassette (not shown) located proximal to the first cassette  806 . 
     The second device module  804  is the most distal module and closest to the patient (not shown). The second cassette  808  of the second device module  804  includes a second device support  830 , e.g., a flexible tube, positioned in a channel  826  of the second cassette  808 . The second cassette  808  and the second device support  830  are moveable relative to one another. Since there is no device module or cassette in front of the second device module  804 , a distal support connection  832  mounted to a distal support arm  834  is used to provide a second front (or distal) fixed point  820  for the distal end of the second device support  830 . The distal support connection  832  and distal support arm  834  are described further below with regard to  FIGS. 108-116 . A second end of the second device support  828  extends out from the proximal end of the second cassette  808  and connects to a second rear (or proximal) fixed point  822  on a proximal end of the support arm  818  connected to the distal support arm  834 . The second device support  830  is held in tension by fixed second front  820  and rear  822  points. The second front and rear fixed points  820  and  822  are kept a constant distance from one another. The second front and rear fixed points  820  and  822  may be rigid or may have some elasticity to account for manufacturing and assembly tolerance. 
     In one embodiment, the distal end of the first device support  828  connected to the first front fixed point  810  and the distal end of the second device support  830  connected to the second front fixed point  820  may be detached or disconnected, as discussed further below, to facilitate loading and unloading of EMDs before, during and after a procedure.  FIG. 80  is a diagram showing a top view of a cassette with a device support in a withdrawn position to facilitate exchange of an elongated medical device in accordance with an embodiment. In  FIG. 80 , a device support  842  of a cassette  840  has been detached from a front (or distal) fixed point  850  and is in a retracted position which exposes an EMD  848  to facilitate loading and unloading of the EMD. As discussed above, the front fixed point  850  is located on a device module distal to the cassette  840 . The device support  842  is shown over the cassette  840  cover in  FIG. 80  for clarity. A first (or distal) end  844  of the device support  842  is located at the distal end of the cassette  840 . A second (or proximal) end  846  of the device support  842  has moved past a rear (or proximal) fixed point  852 . As discussed above, the rear fixed point  852  is located on a support arm of, for example, a cassette, drive module or stage, distal to the cassette  840 . Additionally, the fixed rear point  852  may be attached to the frame of the robotic drive.  FIG. 81  is a diagram showing a top view of a cassette with a device support in an extended position constrained at two ends in accordance with an embodiment. When the device support  842  is pulled over the EMD  848 , the first end  844  is attached to the front fixed point  850  and the second end  846  is constrained by the rear fixed point  852 . As discussed above, the front fixed point  850  and the rear fixed point  852  are fixed relative to a device module the distal end of the EMD  848  is entering. The device support  842  is shown over the cassette  840  cover in  FIG. 81  for clarity. 
     Constraining (fixing) each device support on both ends allows for relative motion between all of the device modules in a robotic drive.  FIG. 82  is a top view of two device modules with device supports in accordance with an embodiment. A first device module  860  has a first device support  868  constrained at a first front (or distal) fixed point  872  at the proximal end of a second device module  862  and at a first rear (or proximal) fixed point  874  located on a proximal end of a support arm  871  of the second device module  862 . The second device module  862  has a second device support  870  that is constrained at a second front (or distal) fixed point (not shown) and a second rear (or proximal) fixed point  875  located in the proximal end of a support arm  873  of a device module (not shown) distal to the second device module  862 . The first device module  860  may be translated forward from a first position  864 . The second device module  862  is at a first position  876 .  FIG. 83  is a top view illustrating forward translation of a device module linearly relative to a device support in accordance with an embodiment. When the first device module  860  moves forward towards the patient (as indicated by arrow  877 ) from the first position  864  to a second position  866 , the first rear (or proximal) fixed point  874  takes the load developed as a cassette of the first device module  860  (and the device module) moves along the first device support  868  (e.g., friction between the cassette and the first device support  868 ). Accordingly, the first device support  868  will not buckle between the distal end of the cassette on the first device module  860  and the proximal end or rear of a cassette on the second device module  862 . As the first device module  860  advances distally toward the second device module  862  (which is stationary at its first position  876  in this example) it moves relative to the first device support  868  as illustrated by reference points A and B located along the length of the first device support  868 . When the first device module  860  is at the first position  864 , reference point A and reference point B on the located proximate to the distal end of the first device module  860 . As the first device module  860  advances along the first device support  868 , the first device support  868  remains stationary because the second device module  862  to which it is coupled via the first distal fixed point  872  and the first proximal fixed point  874  is also stationary. When the first deice module  860  is located at the second position  866 , reference point A and reference point B are located off axis and proximal to the first device module  860 . The first device module  860  may also be translated backwards from the second position  866  to the first position  864 . 
       FIG. 84  is a top view illustrating reverse translation of a device module linearly relative to a device support in accordance with an embodiment. When the first device module  860  moves backwards (retracts) away from the patient (as indicated by arrow  879 ) from the second position  866  to the first position  864 , the first front (or distal) fixed point  872  takes the load developed as a cassette of the first device module  860  (and the device module) moves along the first device support  868  (e.g., friction between the cassette and the first device support  868 ). Accordingly, the first device support  868  will not buckle between the cassette on the first device module  860  and the first rear fixed point  874 . As the first device module  860  moves proximally away from the second device module  862  (which is stationary at its first position  876  in this example) it moves relative to the first device support  868  as illustrated by reference points A and B located along the length of the first device support  868 . When the first device module  860  is at the second position  866 , reference point A and reference point B are located off axis and proximal to the first device module  860 . As the first device module  860  moves proximally (retracts) along the first device support  868 , the first device support  868  remains stationary because the second device module  862  to which it is coupled via the first distal fixed point  872  and the first proximal fixed point  874  is also stationary. When the first device module  860  is at the first position  864 , reference point A and reference point B are the located proximate to the distal end of the first device module  860 . 
       FIG. 85  is a top view illustrating reverse translation of a device support linearly relative to a device module in accordance with an embodiment. When the second device module  862  moves backwards away from the patient (as indicated by arrow  869 ) from a first position  876  to a second position  878 , the second front (or distal) fixed point (not shown) distal to the second device module  862  takes the load developed as a cassette of the second device module  862  (and the device module) moves along the second device support  870  (e.g., friction between the cassette and the second device support  870 ). Accordingly, the second device support  870  will not buckle between the cassette on the second device module  162  and the second rear fixed point  875 . Since the device supports  868  and  870  are each being supported between two known points, the length of each device support does not need to change. As the second device module  862  moves proximally towards the first device module  860  (which is stationary at its first position  864  in this example) the second device module  862  moves relative to the second device support  870 . In addition, the first device support  868  (coupled to the second device module  862  via first distal  872  and first proximal  874  fixed points) moves relative to the first device module  860  as illustrated by reference points A and B located along the length of the first device support  868 . When the second device module  862  is at the first position  876 , reference point A and reference point B are located proximate to the distal end of the first device module  860  as shown in  FIG. 82 . As the second device module  862  moves proximally (retracts) along the second device support  870 , the second device support  870  remains stationary because it is coupled to a more distal device module (not shown) which is stationary in this example. However, the first device support  868  moves proximally with the second device module  862  to which it is coupled via the first distal fixed point  872  and the first proximal fixed point  874 . At the second position  878  of the second device module  862 , reference point A and reference point B are located proximate to the distal end of the first device module  860 . 
       FIG. 86  shows a simplified top view of four device modules and four device supports for a robotic drive in accordance with an embodiment. A first device module  902  incudes a first device support  904  with one end connected to a support arm  918  and one end connected to a distal support point. A second device module  906  includes a second device support  908  with one end connected to a support arm  920  and one end connected to the first device module  902 . A third device module  910  includes a third device support  912  with one end connected to a first front (or distal) fixed point  926  on the second device module  906  and another end connected to a first rear (or proximal) fixed point  928  on a support arm  922 . A fourth device module  914  includes a fourth device support  916  with one end connected to a second front (or distal) fixed point  930  on the third device module  910  and another end connected to a second rear (or proximal) fixed point  932  on a support arm  924 . In various embodiments, the support arms  918 ,  920 ,  922  and  924  may be connected to the drive module or the cassette of a device module. In another embodiment, the support arms  918 ,  920 ,  922  and  924  may be foldable, telescoping or use other methods to shorten the length of the support arm when not in operation.  FIG. 87  shows a simplified top view illustrating movement of a device module relative to a device support in accordance with an embodiment. The third device module  910  starts at a first position  934  (shown with dotted lines) and moves to a second position  936  (as indicated by arrow  946 ). As the third device module  910  moves forward (toward a patient), it moves along the third device support  912  that is fixed to second device module  906  at the first front (or distal) fixed point  926  and is fixed to the support arm  922  extending from the second device module  906  at a first rear (or proximal) fixed point  928 . As the third device module translates, the portion of the device support  912  moving through the third device module  910  changes, while the first front  926  and rear  928  fixed points do not move. The length of a first section  942  of the device support  912  spanning between the second device module  906  and the third device module  910  decreases while the length a second section  944  of the device support  912  spanning between the third device module  910  and the rear fixed point  928  increases. This allows the third device module  910  (and the associated EMDs) to remain fully supported between the span between the third device module  910  and the second device module  906  during linear motion. Another relative motion occurring during the movement of the third device module  910  between the first position  934  and the second position  936  involves the fourth device support  916  of the fourth device module  914  and the second front (or distal)  930  and second rear (or proximal)  932  fixed points for the fourth device support  916 . The fourth device support  916  is fixed to the third device module  910  at the second front fixed point  930  and is fixed to the support arm  924  extending from the third device module  910  at a second rear fixed point  932 . Because the third device module  910  is moving, the second front  930  and rear  932  fixed points are moving as well. A first section  938  of the fourth device support  916  slides through the fourth device module  914 , increasing in length in the span between the fourth device module  914  and the third device module  910  while a second section  940  of the fourth device support  916  decreases in length in the span between the fourth device module  914  and the rear fixed point  932 . 
       FIG. 88  shows a simplified top view illustrating the four device modules of  FIG. 86  in a forward position relative to their respective device support in accordance with an embodiment. In  FIG. 88 , the first device module  902 , the second device module  906 , the third device module  910  and the fourth device module  914  are each shown in the maximum forward position along their respective device support  904 ,  908 ,  912  and  916 .  FIG. 89  shows a simplified top view illustrating the four device modules of  FIG. 86  in a withdrawn position relative to their respective device support in accordance with an embodiment. In  FIG. 89 , the first device module  902 , the second device module  906 , the third device module  910  and the fourth device module  914  are shown in a maximum extended (rear) position along their respective device support  904 ,  908 ,  912  and  916 . In an embodiment, the device support length is determined by the straight length of the device support and the S-shaped spline that takes the device support off the longitudinal device axis of a device module and directs it towards the support arm longitudinal axis. In one embodiment, each device support  904 ,  908 ,  912  and  914  may include compliance to pretention the device support to help with slack when transitioning between forward and reversed directions. 
     As discussed above, each device support is constrained at a rear (or proximal) fixed point that is connected to a support arm extending from a device module in front (e.g., distal to) the device module associate with the device support. In an embodiment, the rear fixed point includes a rear constraint that may be configured to only react tensile forces.  FIG. 90  is a side view of a proximal end of a device support that is extended and a rear constraint for a rear (or proximal) fixed point to which the device support is connected in accordance with an embodiment and  FIG. 91  is a side view of a proximal end of a device support that is partially retracted and a rear constraint for a rear (or proximal) fixed point to which the device support is connected in accordance with an embodiment. A proximal end  952  of a support arm includes a retaining clip  954  which holds the proximal end of the device support  950 . A hard stop  956  is positioned on the end of the device support and is configured to hold the device support in tension when the device support moves forward and allowing the device support to be retracted for device loading (as described above with respect to  FIGS. 80 and 81 ). Forward motion and retraction of the device support  950  is indicated with arrow  958 . An operator may pull back on the device support  950  without removing it from the retaining clip  954 . The rear constraint formed from the retaining clip  954  and the hard stop  956  only reacts tensile forces. The device support will not buckle because the retaining clip  954  cannot react compressive forces. 
     In another embodiment, the tension on the device support provided by front (or distal) fixed point that connects the device support to a more distal device module and a rear (or proximal) fixed point created by storing the proximal end of the device support on a reel or spool at each cassette. In this embodiment, support arms would not be required to provide the fixed point on the proximal end of the device support.  FIG. 92  shows a simplified top view of device modules with device supports stored on a reel in accordance with an embodiment and  FIG. 93  shows an exemplary spooled tensioner in accordance with an embodiment. In  FIG. 92 , each device module  960  includes a reel or spool  962  on which the device support may be wound. An exemplary spooled tensioner is shown in  FIG. 93  that includes a spool  962  on which the flexible tube of the device support  964  is wound. The proximal end of the device support is fixed to the spool  962 . The distal or “free” end of the device support may be pulled out by an operator or robotically actuated by the robotic drive and attached to a front fixed point on a distal cassette. A torque may be applied to the spool to apply tension to the device support  964 . The torque could be applied by a solely mechanical apparatus such as a constant torque spring or a rack and pinion. In another embodiment, the torque may be applied by, for example, a motor (not shown) which is controlled by the control computing system  34  (show in  FIG. 2 ).  FIG. 94  shows a simplified top view of device modules with driven device supports in accordance with an embodiment and  FIG. 95  shows an exemplary geared tensioner in accordance with an embodiment. In  FIG. 94 , each device module  970  includes a drive mechanism  974  which interacts with or engage a device support  972  to provide tension on the device support and allow the device support  972  to move forward and backwards. The drive mechanism may be, for example, a wheel or gear. In one embodiment, the drive mechanism  974  may engage the device support via friction on the walls of the flexible tube of the device support  972 . In another embodiment, the device support may have radial holes along a side which are then engaged by a pin-drive gear, also called a tractor feed. In another embodiment, the device support is a ribbed or convoluted tube and the drive mechanism is a toothed gear that engages and tensions the ribbed or convoluted tube. An exemplary geared tensioner  976  is shown in  FIG. 95  that engages a convoluted flexible tube  978 . 
     In another embodiment, the device support may be an accordion or spring.  FIG. 96  shows a simplified top view of device modules with device supports formed with accordions or springs in accordance with an embodiment. In  FIG. 96 , a device support between the device modules  980  is formed from an accordion element  986  and two linear guides  984  which are positioned in parallel to one another on opposite sides of the accordion element  986 . An EMD  982  is positioned through openings  992  (shown in  FIG. 98 ) in each segment  994  (shown in  FIG. 98 ) of the accordion element  986 . The accordion based device support is always in tension. In one embodiment, the accordion device support has compliance built in such that is capable of handling the relative translational motion between two device modules  980 . Even though the accordion member acts as a tensile spring and typically stays in tension, it may still deflect from the device axis when axial load is applied. The linear guides (or guiding rails)  984  shown in  FIG. 96  constrain the accordion so it is limited in deflection away from the device axis. In one embodiment, the linear guides  984  of a first device module mount to the proximal end of the more distal second device module and the other end of the linear guides  984  are free to slide through the accordion and the first device module. An embodiment where four accordions exist to support four device modules can have the accordion linear guides offset so that the linear guides for not interfere with one another when the device module are close.  FIG. 97  illustrates a compressed state  988  of the accordion element  986 . The linear guides are not shown in  FIG. 97  for clarity.  FIG. 98  illustrates a stretched state  990  of the accordion element  986 . The linear guides are not shown for clarity. The accordion element  986  includes multiple segments  994  that each include an opening  992  through which an EMD may be positioned. The number of segments  994  and the lengths of the segments  994  may be optimized so that the unsupported distance between discrete segments  994  is such that an EMD will not buckle at maximum loads experienced during a procedure. The accordion device support has multiple flexures which auto-balance to give equal spacing regardless of the overall tension so that no single gap across the length of a segment  994  becomes large enough for buckling. In other words, the gaps across each segment  994  length want to be the same across all segments  994 . This helps minimize the unsupported distance an EMD needs to travel, which allows the accordion element  996  to reach higher loads before buckling. 
     The profile of a device support formed from a flexible tube should support being opened and closed, for example, to allow EMDs to be loaded into the device support. When the slit at the distal end of the device support flexible tube is forced apart (e.g., using a splitter as discussed further below), the device support may be advanced to encapsulate the EMD and when, closed, the EMD is adequately supported and retained so as to not pop out and buckle.  FIGS. 99A-C  are perspective views of exemplary slit shapes for a device support flexible tube in accordance with an embodiment. In  FIG. 99A , a device support flexible tube  1000  is shown with a straight slit  1002  lengthwise along the tube. In another example, a device support flexible tube  1000  may have a serrated shaped slit  1004  lengthwise along the tube as shown in  FIG. 99B . In yet another examples, a device support flexible tube  1000  may have a wave shaped slit  1006 , similar to a sine wave, lengthwise along the tube as shown in  FIG. 99C . The slit of the device support  1000  may be opened by a wedge or splitter (shown in  FIG. 102-104  and discussed further below) that is positioned close to an entry point for an EMD to the device support. The wedge or splitter spreads the opening wide enough to clear the EMD. The elasticity of the flexible tube causes the slit to recover and close on the other side of the EMD, encapsulating and retaining the EMD. The serrated shape and shape similar to a sine may be used so that the material in the area of the slit overlaps so as to improve EMD retention in the device support. 
     The EMDs utilized in a robotic drive for an interventional procedure may vary in size, for example, the various EMDs that may be used may vary from 9FR to 2FR or even a 0.010″ guidewire. For example, in a multi-axial robotic drive configured for an endovascular therapy procedure to treat acute ischemic stroke, it can be expected that the first EMD in the device stack-up is between 6 and 9 FR. The second and third EMDs in the device stack-up may be between 2.5 to 6 FR. The fourth EMD may be a wire-based EMD with a diameter between 0.010 to 0.038″. In order to properly support and retain EMDs with different sizes, different device supports may be provided for each EMD where the device support for each EMD is designed to work with the corresponding size of EMD. For example, by minimizing the diametrical clearance between the EMD and the device support tube, any device buckling inside the tube will store less energy and have less linear motion hysteresis. In an embodiment, the device support of each cassette may be designed to be modular so that the correctly sized device support may be added to a cassette based on the EMD being supported by the cassette. In addition, a splitter and device support connector (both discussed further below with respect to  FIGS. 102-107 ) that are designed to work with a specific size of EMD may also be modular and switched based on the specific size of EMD being supported by a cassette. In another embodiment, different versions of a cassette may be provided for each subset of device sizes, where the cassette has an appropriately sized device support pre-installed. The appropriate cassette design for the specific size or range of sizes of an EMD may be mounted to a drive of the robotic drive and removed when a different design is needed for a different size of EMD or a different size range. For example, a cassette may be designed to support a range of sizes of the wire-based EMD which can vary between 0.010″ and 0.038″. 
     As discussed above with respect to  FIG. 3 , a device module  32  of a robotic drive  24  includes a drive module  68  and a cassette  66  mounted on and releasably coupled to the drive module  68 .  FIG. 100  is an exploded view of a device module and an elongated medical device in accordance with an embodiment. A drive module  1010  includes a mounting surface  1012  and a coupler  1014 . A motor and a drive belt (not shown) may be housed in the drive module  1010  and connected to the coupler  1014 . The motor and belt are used to control a rotational position of the coupler  1014 . Drive module  1010  may include an encoder (not shown) for device position feedback. The drive module  1010  shown in  FIG. 100  has one coupler  1014 , however, it should be understood that the drive module  1010  may have more than one coupler  1014  and more than one motor. (for example, one motor for each coupler or one motor driving multiple couplers) The rotation of the coupler  1014  may be used to provide another degree of freedom for an EMD positioned in a cassette  1016  that may be mounted on the mounting surface  1012  so as to interface with the coupler  1014 . For example, the coupler  1014  may be used to rotate an EMD  1024  when the EMD is positioned in the cassette  1016 . If the drive module  1010  has two or more couplers  1014 , each coupler may be used to provide a degree of freedom for an EMD. 
     As mentioned, a cassette  1016  may be positioned on the mounting surface  1012  of the drive module  1010  and used to interface with an EMD  1024  positioned in the cassette  1016 . As mentioned above, the drive module  1010  may be configured to have at least one dimension that is smaller or less than at least one dimension of a cassette  1016  as shown in  FIG. 100 . For example, a length of the drive module  1010  as measured from a proximal side to a distal side when the device module  1010  is coupled to a linear member or rail may be smaller or less than a length of the cassette  1016  along a longitudinal axis of the cassette. In some embodiments, the size and dimensions of the drive module  1010  are minimized so that, for example, the drive module  1010  takes up a minimal amount of space along a linear member or rail (e.g., linear member or rail  60  shown in  FIG. 2 ) of the robotic drive when not populated with a cassette  1016 . The cassette  1016  includes a housing  1018 . In an embodiment, the cassette housing  1018  may be releasably attached to the drive module  1010 . The drive module  1010  may also include one or more additional elements  1013  on the mounting surface  1012  such as, for example, positioning pins, alignment pins, etc. to interact with elements on a cassette  1016  (e.g., connection points, slots, channels, etc.) to enable a releasable attachment of the cassette  1016  to the drive module  1010 . In one embodiment, cassette housing  1018  is releasably connected to the drive module  1010  using a quick release mechanism  1021 . In one embodiment, the quick release mechanism  1021  includes a spring-biased member in cassette housing  1018  that is actuate by a latch release  1023  that releasably engages with a quick release locking pin  1015  secured to the drive module  1010 . 
     The cassette housing  1018  includes a cradle  1020  configured to receive the EMD  1024 . A bevel gear  1022  is used to interface with the coupler  1014  of the drive module  1010  and to interface with the EMD  1024  to rotate the EMD  1024 . In one embodiment, EMD  1024  is provided with an on-device adapter  1026  (discussed above with respect to  FIGS. 23-25 ) to interface the EMD  1024  to the cassette  1016 , for example, an interface to bevel gear  1022 . In the example shown in  FIG. 100 , the EMD is a guidewire and the on-device adapter  1026  is a collet with a gear  1027 . When power is transferred from the device module  1010  to the gear  1022  in the cassette  1016  (e.g., via the coupler  1014 ), the gear  1022  in the cassette interacts with the gear  1027  on the collet to rotate the guidewire  1024 . A device support  1028  is positioned in the cassette in a channel  1042  which may be covered by the housing  1018 . As discussed above, the device support  1028  and the cassette  1016  are configured to move relative to one another. The device support  1028  includes a connector  1030  which is used to connect to a device module (e.g., to a cassette, to other elements of the device module, or to elements positioned in the device module) distal (or in front of) the cassette  1016  in a robotic drive. Connector  1030  includes a recess  1032 . In a withdrawn or retracted position, the connector  1030  is positioned in a recess  1036  in the housing  1018  on a distal end  1034  of the cassette  1016 . As discussed above, the connector  1030  and device support  1028  may be pulled outward from the cassette  1016  so the connector may be attached to a more distal cassette in the robotic drive. A forward constraint  1040  is provided on a proximal end  1038  of the cassette  1016  and is used to connect to a connector of a device support on another cassette proximal to (or behind) the cassette  1016  in a robotic drive.  FIG. 101A  is a perspective view of a cassette with a device support installed and in a retracted position in accordance with an embodiment. In the retraced position, the connector  1030  is positioned in the recess  1036  in the housing  1018  at the distal end  1034  of the cassette  1016 .  FIG. 101B  is a perspective view of a cassette with a device support installed and in a retracted position in accordance with an embodiment. The device support  1028  is positioned in a channel  1042  of the cassette. The cassette  1016  incudes a proximal support member  1031  positioned on the proximal end  1038  of the cassette  1016 . The proximal support member  1031  includes an opening and is configured to provide support to the device support  1028 . Device support  1028  is positioned in and passes through the opening  1033 . The opening  1033  is sized so that the device support can move through the opening  1033  as the device support  1028  is advanced and retracted. 
       FIG. 102  is a top view of a device support and connector extended from a cassette ahead of an EMD entry point in accordance with an embodiment. A device support  1028  and connector  1030  are extended out from the recess in the distal end  1034  of the cassette housing. A guide  1044  and a splitter  1048  are positioned in the recess  1036  on opposite sides of the path of the device support  1028  as it is moved into and out of the recess  1036  and channel  1042 . In the extended position, the device support encapsulates an EMD  1024 . The EMD enters the device support  1028  at an EMD entry point  1046  which is located between a proximal section and a distal section of the splitter  1048 . The proximal and distal sections of the splitter are shown with dotted lines. As mentioned above, the device support  1028  includes a lengthwise slit so the distal end of the device support may be forced apart (e.g., by using a splitter as described below) and closed to allow the device support to encapsulate an EMD as the device support is advanced. The connector  1030  holds open an end of the device support tube allowing it to pass over the splitter  1048  as shown in  FIG. 104 . Referring to  FIGS. 102 and 104 , the splitter  1048  holds the slit in the device support  1028  open as the EMD  1024  is encapsulated by the device support  1028  as the connector  1030  and device support  1028  pass over the splitter  1048  and EMD entry point  1046 . The end of the device support tube  1028  is positioned in a recess  1032  of the connector. Using the splitter  1048  to hold open the device support  1028  on both sides of EMD entry point  1046  reduces or eliminates friction forces on the EMD  1024 . For example, this prevents the walls of the device support  1028  tube from rubbing the EMD  1024  which can cause damage to the EMD  1024  at the entry point and would introduce noise to a load sensing system (not shown) which may be used to read the force or torque the EMD is subjected to. The EMD  1024  passes through a cavity  1052  in the center of the splitter  1048 . The connector  1030  and the splitter  1048  are designed so that the device support  1028  is held open as it passes over a gap between the proximal and distal section of the splitter  1048 . Splitter  1048  is also designed such that the unsupported length of the EMD  1024  at any point is not such that it can catastrophically buckle. Guide  1044  is configured to guide the device support  1028  over the gap and retain the device support  1028  on the splitter  1048 . As mentioned above, the splitter  1048  may be designed for specific EMD and device support size ranges.  FIG. 103  is a top view of a device support and connector withdrawn behind an EMD entry point in accordance with an embodiment and  FIG. 105  is a top view of cassette with a device support connector withdrawn and off of a device axis to facilitate loading of an EMD in accordance with an embodiment. To facilitate loading of an EMD  1024  in a cassette  1016  (shown in  FIG. 100 ), the device support  1028  and connector  1030  are retracted into the recess  1036  before an EMD  1024  is loaded. As shown in  FIGS. 103 and 105 , the connector  1030  may be retracted onto the splitter  1048  and guide  1044  and behind (or proximal to) the EMD entry point  1046 . In addition, the retracted (or withdrawn) position of the connector  1030  is off of a longitudinal EMD axis  1050 . This allows for EMD placement into cassette  1016 , for example, loading a side loading EMD. Retracting the connector  1030  behind the EMD entry point also reduces the unsupported EMD length and reduces working length loss. 
     As discussed above with respect, the connector  1030  and device support  1028  may be pulled outward from the cassette  1016  so the connector may be attached to a more distal device module (e.g., a cassette of the device module) in the robotic drive. In an embodiment, a forward constraint  1040  (shown in  FIG. 100 ) may be provided on a proximal end  1038  of a first cassette and is used to connect to a connecter of a device support on a second cassette proximal to (or behind) the first cassette in the robotic drive.  FIG. 106  is a perspective view of a forward constraint and a connector in accordance with an embodiment. Forward constraint  1040  includes a latching mechanism  1054 , for example, a spring latch. A connector  1030  of a device support  1028  from a proximal cassette (not shown) is attached to the spring latch  1052 . In one embodiment, the connector  1030  connects to the latching mechanism  1054  by pushing the connector  1030  into the foreword constraint  1040 . In an embodiment, the latching mechanism  1054  may require no secondary motion other than axial translation to engage the latching mechanism  1054 , but may require one or more additional movements to disengage the latching mechanism  1054  and remove the connector from the forward constraint  1040 . For example, there may be buttons, levers or knobs which may need to be released before the connector  1039  becomes disengaged. The connector  1030  may be manually disengaged or disengaged using a control computing system  34  (shown in  FIG. 2 ). The connector  1030  attaches to the forward constraint  1040  approximately along the longitudinal EMD axis  1050  of an EMD (not shown) contained in the device support  1028 . This prevents shearing of the EMD by moving perpendicular to the lathing mechanism  1054 . In another embodiment, a secondary latch or tightening mechanism may be provide to further secure the connector  1030  and reduce play.  FIG. 107  is a perspective view of a forward constraint with a lid in accordance with an embodiment. In  FIG. 107 , a lid  1056  is connected to the forward constraint  1040 , for example using a pivot. The lid  1056  may be closed over the connector  1030  and latched to further constrain the connector  1030  in the forward constraint  1040 . 
     As discussed above with respect to  FIG. 3 , a distal support connection mounted to a distal support arm may be used to provide a front (or distal) fixed point to support the distal end of the device support in the cassette of the most distal device module in the robotic drive, i.e., the device module closest to the patient.  FIG. 108  is a perspective view of a distal support arm and distal support connection in accordance with an embodiment. A cassette  1062  is mounted to a drive module  1064  which is connected to a stage  1066  using an offset bracket  1068 . The stage  1066  is moveably mounted to a rail or linear member  1060  and may be moved linearly along the rail  1060 . A distal support arm  1070  may be attached to a frame of the robotic drive, for example, a frame of the rail  1060 . In one embodiment, the distal support arm  1070  may be rigidly attached to the frame. In another embodiment, the distal support arm  1070  may be attached to a patient table or the patient. The distal support arm  1070  extends away from the robotic drive and is connected to a device support connection  1072  to provide a distal fixed point for the device support. In one embodiment, the distal support arm  1070  may also be used to provide a distal define for the cassette  1062  and drive module  1064 . A distal define is used to define the most distal aspect of the most distal device (e.g., cassette  1062  and drive module  1064 ) of the robotic drive. In another embodiment, the distal define may be provided using a separate distal define arm (not shown) that may be coupled to, for example, the frame of the robotic drive. The distal support connection  1072  may also be coupled to an introducer sheath hub. An introducer interface support  1076  may be connected to the device support connection  1072 . A connector  1074 , for example, a connector on a distal end of a device support as described above with respect to  FIGS. 102-105  may be attached to the device support connection  1072  to provide a distal fixed point and support for the distal end of the device support. A device support is not shown in  FIG. 108 , but would be positioned in the cassette  1062  as shown in  FIG. 109 .  FIG. 109  is a perspective view of a distal support connection coupled to a device support and connector in accordance with an embodiment. A device support  1078  is shown as a dotted line encapsulating an EMD  1079  and extending between the cassette  1062  and the device support connection  1072 . The connector  1074  is attached to the device support connection  1072 . The device support connection  1072  may be, for example, a forward constraint such as described above with respect to  FIGS. 106 and 107 . The device support connection  1072  is mounted to a distal support arm  1070  and may be connected to an introducer interface support  1076 .  FIG. 110  is a side view of a distal support arm, distal support connection and an introducer interface support in accordance with an embodiment. The introducer interface support  1076  is configured to support an EMD  1079  (shown in  FIG. 109 ) between the device support  1078  (shown in  FIG. 109 ) and an introducer sheath  1075  connected to a distal end of the introducer interface support  1076  as discussed further below. The introducer interface support  1076  ensures that the EMD  1079  does not buckle or prolapse between the distal end of the device support  1078  and the hub of an introducer sheath  1075 . In an embodiment, the introducer interface support  1076  may also be used to redirect an EMD from a position that is axially aligned with the robotic drive device axis  1065  to a position that is axially aligned with the introducer sheath  1075  or other supporting member. 
     The introducer sheath  1075  is inserted at an access point (e.g., the femoral artery) into a patient&#39;s vasculature that will lead the EMD to the target location in the patient (e.g., a lesion). The introducer sheath  1075  should be held in place so that it does not come out of the patient. In one embodiment, the distal support arm  1070  and the device support connection  1072  may be used to fix the position of the introducer sheath  1075  and may react forces on the introducer sheath  1075  created from the friction between the introducer sheath  1075  and the EMD moving inside of the introducer sheath  1075 . In another embodiment the introducer sheath  1075  may be support by a separate structure than the distal support arm  1070  and device support connection  1072 , for example, the introducer sheath may be attached to the patient or a patient table using known methods. 
       FIG. 111  is a perspective view of an introducer interface support connected to an introducer sheath in accordance with an embodiment. The introducer interface support  1076  is connected at its proximal end  1080  to a device support connection  1072  that is connected to a distal support arm  1070 . An introducer sheath  1075  is connected to a distal end  1082  of the introducer interface support  1076 . The introducer interface support  1076  may be configured to receive the introducer sheath  1075  with a side port (not shown). The side port and its tubing (not shown) can allow for administration of medicine, contrast or saline injection or drawing blood samples. An EMD (not shown) enters the body of a patient through the introducer sheath  1075  which is inserted into a vessel (typically an artery). In one embodiment, the introducer interface support  1076  opens to allow the EMD to be placed in the introducer interface support  1076 . In another embodiment, an EMD may be inserted axially into the introducer interface support  1076 . In another embodiment, the EMD and introducer interface support  1076  may be frictionally fit so that the introducer interface support  1076  does not need to open or have the EMD inserted axially. As mentioned, the introducer interface support  1076  provides support to the EMD in the distance between the connector  1072  and the introducer sheath  1075 . The introducer interface support  1076  may be rigid (as shown in  FIG. 111 ) or flexible. For example, the introducer interface support  1076  may be made of flexible material or the introducer interface support  1076  may have a joint near the device support connection  1072  which allows for a limited range of motion of the distal end  1082  (where the introducer sheath  1075  is held) to account for perturbation of the robotic drive or movement of the patient. 
     In another embodiment, the distal support arm  1070  may be movably connected to the robotic drive. A moveable distal support arm  1070  may have one or more degrees of freedom to account for excess exposed EMD length that may not need to be actuated. For example, with shorter patients and/or less tortuously, more of the first guide catheter may be exposed because it will never need to enter the patient. If the distal support arm (and therefore the device support connection  1072 ) can move forward, it can account for the excess length of the guide catheter that does not need to be actuated. This may also help reduce the overall length of the rail or linear member  1061  (and rail  1060  shown in  FIGS. 108 and 110 ).  FIG. 112  is a perspective view of a movable distal support arm in a first position in accordance with an embodiment. A distal support arm  1070  may be moveable connected to a rail  1061  using a stage  1090 . In  FIG. 112 , the distal support arm  1070  is in a first position  1094  where the distal support connection  1072  is located proximate to the distal end of a device module  1092 . The stage  1090  may be manually or robotically moved along the rail  1061  to change the position of the distal support arm  1070 .  FIG. 113  is a perspective view of a moveable distal support arm in a second position in accordance with an embodiment. In  FIG. 113 , the stage  1090  and the distal support arm  1070  have been moved linearly to a second more distal position  1096  from the device module  1092 . Accordingly, the device support connection  1072  and the device module  1092  are separated by a distance  1095 . In the embodiment shown in  FIGS. 112 and 113 , the distal support arm  1070  has one degree of freedom. In another embodiment, the distal support arm  1070  may be an articulating or driven arm with multiple degrees of freedom. 
     As discussed above, each end of the device support may be connected to fixed points (front (or distal) and rear (or proximal)) to provide appropriate tension to the device support between device modules or between most distal device module and a device support connection to prevent an EMD from buckling. The device support connection  1072  described above provides a front (or distal) fixed point for the device support of the most distal cassette in the robotic drive. The device support of the most distal cassette may be provided with a rear (or proximal) fixed point using a support arm (e.g., support arm  77  shown in  FIG. 3 ) that is connected to the distal support arm  1070 . For a moveable distal support arm, the support arm will also be moveable.  FIG. 114  is a top view of a moveable distal support arm and movable support arm in a first position in accordance with an embodiment. In  FIG. 114 , a distal support arm  1110  is in a first position  1114 . A device module  1106  is connected to a rail or linear member  1100  using a first stage  1102 . A device support  1108  is positioned in the device module  1106  (e.g., in a cassette of the device module) and a distal end of the device support  1108  is connected to a device connection point  1111  (front (or distal) fixed point) connected to the distal support arm  1110 . A proximal end of the device support  1108  is connected to a proximal end of a support arm  1112  at a rear (or proximal) fixed point  1109 . A second stage  1103  is connected to the rail  1100  (or a different rail (not shown) in the system) and may be manually or robotically moved along the rail  1100  to change the position of the distal support arm  1110  and the support arm  1112 .  FIG. 115  is a top view of a moveable distal define arm and movable support arm in a second position in accordance with an embodiment. In  FIG. 115 , the second stage  1103 , the distal support arm  1110  and the support arm  1112  have been moved linearly to a second more distal position  1116  from the device module  1106 . The support arm  1112  moves with the device support connection  1111  so there is always the same length of the device support  1108  between the device support connection  1111  and the rear fixed point  1109 .  FIG. 116  is a top view illustrating movement of a distal support arm and a support arm from the second position to the first position in accordance with an embodiment. In  FIG. 116 , the device support connection  1111 , the support arm  1112 , the distal support arm  1110  and the second stage  1103  start at the second position  1116  (indicated by dotted lines). The second stage  403  may be actuated to move linearly along the rail  1100  to the first position  1114  as indicated by arrow  1118 . The first position of the device support connection, the support arm, the distal support arm, the rear fixed point, and the second stage are indicated by the reference numbers  1111 ′,  1112 ′,  1110 ′,  1109 ′, and  1103 ′, respectively. 
     Using a catheter-based procedure system with a robotic drive to perform a procedure can involve loading and unloading devices into and out of the system and exchanging devices. For loading/unloading a device, the device being loaded/unloaded is inside the next distal EMD with a more proximal device (e.g., a microwire) that has an indwelling portion. A device exchange involves having a more proximal device (e.g., a microwire) with an indwelling portion and the device that is being unloaded needs to be removed from the proximal device without disturbing the location of the indwelling. The speed, safety and efficiency of exchanges may be impacted by various factors including the experience level of the user or operator, the time-critical nature of the type of procedure (e.g., an endovascular treatment of acute ischemic stroke) and the robotics of the system may apply additional constraints, steps or challenges. Each of these factors can increase the time for an exchange for a robotic procedure when compared to a manual procedure. The methods, apparatus and processes described below may be used to make exchanges faster, safer, and more consistent. 
     Full driving an EMD is defined as initially actuating the EMD from a starting position with the distal tip of the EMD slightly inserted into a more distal EMD so that the EMD does not protrude distally out of the more distal EMD and advancing the EMD as far as is needed which may be up to its entire working length. The length required for a robotic drive that is configured to hub drive an EMD and is capable of fully driving an over-the-wire EMD, the actuating length would be the length of all the EMDs that may be used added end to end. The actuating length may also take into account the lengths of the hubs of the device, the lengths of the hemostasis valve y-connectors and gear adapter, and the distance between device modules For example, for a robotic drive configured for endovascular treatment of acute ischemic stroke that includes a guide catheter (e.g., with a length of 95 cm), an aspiration catheter (e.g., with a length of 135 cm), a microcatheter (e.g., with a length of 165 cm) and a microwire (e.g., with a length of 180-200 cm), the robotic drive actuating distance would need to be almost 7 meters long. To reduce the length, a manual loading procedure may be used that allows a bedside operator, with at least minimal experience, to load and unload an EMD without risking vascular damage to the patient. 
       FIG. 117  is a block diagram illustrating loading or unloading an EMD in a robotic drive with a safe loading distance in accordance with an embodiment. For loading an EMD, an operator takes second EMD  1126  (or in other embodiments more than one EMD) and inserts the second EMD  1126  into a hub of a more distal first EMD  1124 . For example the first EMD  1124  may be a guide catheter and the second EMD  1126  may be a distal access catheter. The robotic drive (e.g., a control computing system) may be configured to automatically position a second device module  1122  (coupled to a rail or linear member  1132 ) at a distance from a first device module  1120  (coupled to the rail  1132 ), herein referred to as a loading offset  1130 . The loading offset is selected so that when the operator places the second (proximal) EMD  1126  into the second device module  1122 , the second EMD  1126  will not exit a distal end  1134  of the more distal first EMD  1124 . Therefore, the second EMD  1126  will not be exposed to the vasculature. In order for the second (proximal) device module  1122  to be positioned properly, a relative distance from the first (more distal) device module  1120  must be known. The loading offset  1130  may be based on a desired gap  1128  (e.g., 5 cm) between the distal end  1134  of the first EMD  1124  and a distal end  1136  of the second EMD  1126  when the second EMD  1126  is being loaded, the length of the first (distal) EMD  1124  and the length of the second (proximal) EMD  1126 . In another embodiment, various parameters of the robotic drive may also affect the loading offset  1130 , such as, for example, hub length and geared adapter length. In various embodiments, the loading offset  1130  may be defined by the difference in EMD lengths (min distal device module EMD length, max loading EMD length), different use cases, input by an operator based on the length of EMDs used or may be determined by the catheter-based procedure system by scanning EMDs opened during the case. The catheter-based procedure system (e.g., a control computing system) may automatically drive the second device module  1122  (e.g., along the rail  1132  of the robotic drive) to the correct position along the rail  1132  with the correct loading offset  1130 , for example, in response to a user input provide by the operator. In another embodiment, the second device module  1122  may be jogged by an operator to the correct position along the rail  1132  with the correct loading offset  1130 . In yet another embodiment, the second device module  1122  may be manually back driven by an operator to the correct position along the rail  1132  with the correct loading offset  1130 . To unload an EMD when they are inside a patient&#39;s body, the robotic drive or the physician may drive the second device module  1122  to the position along the rail  1132  the loading offset  1130  distance from the first device module  1120 . This ensures that a bedside operator is not manipulating EMDs that ae directly surrounded by the patient&#39;s vasculature. While one loading offset  1130  is described with respect to  FIG. 117 , in other embodiments more than one loading offset may be used where each loading offset provides a zone for safe loading or unloading of an EMD. 
     When calculating the loading offset  1130 , various additional factors may be used. The factors that are used in the calculation may be based on the desired workflow of the catheter-based procedure system. The additional factors may include where the device modules with the EMDs that are being exchanged are currently positioned along a rail, the current stack of devices in the robotic drive and the stack of devices that are to be loaded into the robotic drive. Another factor is if a device module is far enough proximal and additional cassettes are being added distal (e.g., going from a biaxial configuration to a triaxial configuration), the device module may need to be moved distally to allow the additional cassettes to be added to the robotic drive. 
     One example of why the EMD length is important to know is when a physician is trying to reach a distal clot. The typical stack of EMDs for distal aspiration would be a Guide Catheter (95 cm), Aspiration Catheter (135 cm), Microcatheter (165 cm), and Guidewire (300 cm). If the 165 cm Microcatheter cannot reach the clot because it is “hubbed out” behind the aspiration catheter and Guide Catheter (the devices are at the max forward position), the physician may remove the Aspiration Catheter and insert the Micro Catheter directly into the Guide Catheter. By doing this, the physician can increase the amount of Micro Catheter inserted into the body because they have eliminated the length of the hub of the aspiration catheter and the hemostasis valve on the back of the aspiration catheter. The impact of this change is realized when loading the microcatheter behind the guide catheter. What used to be a 135 cm Aspiration Catheter being loaded behind a 95 cm Guide Catheter is now a 165 cm Micro Catheter being loaded behind a 95 cm Guide Catheter. If the same loading position was used, the Micro Catheter tip would be 30 cm forward, well into the vasculature of the patient. By knowing the length of the EMD being loaded and the length of the EMD it is begin loaded into and using the methods described herein for determining and implementing a safe loading offset, the catheter-based procedure system/robotic drive may ensure that a safe loading distance for all use cases. 
     Various methods may be used by the catheter-based procedure system/robotic drive to determine the length of the EMDs in a device module. For example, the catheter-based procedure system/robotic drive may determine the EMD lengths for each device module by electrical or optical identification (RFID, Barcode, QR, etc.), the operator manually entering the EMD length data or having a range of designated EMD lengths and choosing the combination of lengths that would result in the device module being driven as far back as possible (worst or the worst, i.e., safest conditions). To enable the use of a safe loading offset, the robotic drive may be configured to detect when a device module is unpopulated (no EMD loaded in the cassette) and move the unpopulated device module out of the way of a device module that needs to reach the loading offset. During use, device modules may interfere with the planned paths of other device modules, so the ability to avoid crash states is important. In another embodiment, if the user is jogging a device module backwards to get it to the loading position, and it runs into another device module, instead of going into a “crashed” state where both device modules are deactivated, the command for the device module being jogged would also be sent to the device module obstructing its path so as to move both device modules in the same direction. 
     There are multiple methods for inserting an EMD while limiting the EMDs travel forward. In one example, the EMD hub may be dropped into the device module it is being loaded into and the operator ensures the EMD hub is fixed (i.e., the EMD cannot move forward when device is being inserted). The EMD, or set of EMDs, are then inserted into a more distal EMD. When the inserted EMD approaches the loading offset distance, it will become taut, no longer being able to be inserted any further into the patient. In another example, the EMD to be loaded may be axially inserted through the cassette it is being loaded into. The cassette acts as a hard stop, not allowing the EMD hub to be inserted further into the patient. In another example, a mechanical clip may be attached to the EMD shaft to act as a hard stop when being inserted into the more distal EMD Hub. 
     In an embodiment, the robotic drive (e.g., a control computing system of the robotic drive) may be configured to correctly position an on-device adapter on a wire-based device to allow for a designated amount of throw. In another embodiment, the robotic drive (e.g., a control computing system of the robotic drive) may be configured to generate and provide an alert (e.g., a visual or audible alert) to indicate if the current positions of the device modules along a rail in the robotic drive would not allow all EMDs to be loaded based on, for example, the lengths of the EMDs. In another embodiment, the robotic drive (e.g., a control computing system of the robotic drive) may be configured to provide a notification (e.g., on a display) of where (i.e., what position along the rail) to drive one or more device modules. For example, a user may then command the robotic drive (e.g., using a control station) to drive the one or more device modules based on the position information provided by the robotic drive. In this embodiment, the robotic drive may also be configured to provide a notification (e.g., on a display) when the device modules are in a safe location. 
     In a manual neuro procedure, technicians will often prepare a multitude of EMDs on a separate sterile table behind the catheter-procedure system table. These EMDs will often be loaded into one another, then loaded into an EMD already inserted into the patient. For example, a distal access catheter, a micro catheter, and a 0.014 guidewire may be assembled together, then the set of prepared EMDs are all be loaded into a guide catheter once access to the carotid artery is gained. The robotic drive, for example, robotic drive  24  shown in  FIG. 3 , may be configured so that a prepared (or preassembled) “sub-assembly” (or set) of EMDs may be side loaded into two or more of the device modules of robotic drive. In an embodiment, the prepared set of EMDs is loaded into two or more of the device modules at substantially the same time. In another embodiment, each EMD in the preassembled set of EMDs may be loaded into the device modules consecutively.  FIG. 118  is a top view of device modules of a robotic drive in a loading position in accordance with an embodiment. A first device module  1140  is in the most distal device module position and has a first device support  1148  that is extended and encapsulates a first EMD  1156  that is supported by the first device module  1140 . A second device module  1142 , a third device module  1144  and a fourth device module  1146  are positioned proximal to the first device module  1140 . The second  1142 , third  1144  and fourth  1146  device modules have a second device support  1150 , a third device support  1152  and a fourth deice support  1154 , respectively. Each of the second  1150 , third  1152  and fourth  1154  device supports are pulled to their most proximal position and a cassette cover of a cassette (not shown) loaded onto each device module  1142 ,  1144  and  146  is opened to facilitate loading of an EMD into the respective device module. In one embodiment, the robotic drive may include sprung members to aid in usability when opening cassette covers and retracting device supports to enable loading. In another embodiment, the robotic drive may include actuated members to aid in usability when opening cassette covers and retracting device supports to enable loading. In this embodiment, the robotic drive may be configured to robotically control the actuating members. 
       FIG. 119  is a top view of the device modules of  FIG. 118  in a loading position and a set of prepared EMDs in accordance with an embodiment. A sub-assembly or set of EMDs  1164  is prepared (or preassembled) that includes a second EMD  1158 , a third EMD  1160  and a fourth EMD  1162 . The tip of the second EMD  1158  is inserted into a y-connector installed on the first device module  1140 . With the cassette cover open and the device supports  1150 ,  1152 ,  1154  retracted to their most proximal position, the set of EMDs  1164  may be loaded into their respective device module all at once as indicated by arrows  1166 . Namely, the second EMD  1158 , third EMD  1160  and fourth EMD  1162  may be loaded at the same time into the second device module  1142 , third device module  1144  and fourth device module  1146 , respectively.  FIG. 120  shows the each EMD  1158 ,  1160 ,  1162  in the sub-assembly of prepared EMDs  1164  loaded into their respective device module. 
     In an embodiment, an on-device adapter (discussed above with respect to  FIGS. 23-25 ) may be added to one or more of the EMDs in the subassembly of EMDs (or device stack) at a prep table which allows the EMDS to be exchanged into the system without the need of adding or removing specialized cassettes. In addition, the design described with respect to  FIGS. 118-120  enables a multitude of coaxial devices to be loaded into the robotic drive. This design also may help with safety as an operator may convert a robotic procedure to a manual procedure by removing all the EMDs and continuing a case without large cassettes or device support mechanisms still attached to the EMDs. Only smaller devices such as the on-device adapters (e.g., a gear adapter or collet) would remain attached to the EMDS. Being able to remove an entire device stack (e.g., a prepared sub-assembly of EMDS) out of the cassettes of the device modules and the side loading/unloading design helps enable conversion to a manual procedure from a robotic procedure. 
     As discussed above, various embodiments utilize an on-device adapter that is positioned on the shaft of an EMD (e.g., a wire-based EMD). The position of an on-device adapter on one or more EMDs can be important for the loading/unloading or exchange of an EMD using a safe offset as described above with respect to  FIG. 117  and the loading of a preassembled set of EMDs as described above with respect to  FIGS. 118-120 . For example, if the on-device adapter is positioned too far proximal on the EMD, the distal tip will extend out of the catheter tip when loading/unloading or attempting an exchange using a safe loading offset which can cause vascular damage. If the on-device adapter is placed too far distal on the EMD, the EMD may not have enough forward throw to extend past the distal tip of the, for example, catheter within which the EMD is positioned. Setting the on-device adapter at a known position along the EMD helps enable safe and effective workflows. 
     In various embodiment, a gapping tool may be used to enable setting the on-device adapter at a specific location on an EMD. The gapping tool is configured to have the correct offset designating the amount of throw the on-device adapter should have when being loaded into the robotic drive. The gapping tool may be used both on a separate sterile table behind the catheter-procedure system table when the EMD is being prepared or when the EMD is being loaded into the robotic system. In one embodiment, the gapping tool may be configured to position the on-device adapter based on the alignment of the distal tip of the EMD and the distal tip of the catheter in which the EMD is positioned.  FIG. 121  is a schematic diagram of an elongated medical device, a gapping tool and an on-device adapter in accordance with an embodiment. In  FIG. 121 , a gapping tool  1170  is positioned next to and along an EMD  1174  (e.g., a wire-based EMD) between a y-connector (or hub)  1182  of a catheter  1176  and an on-device adapter  1172 . The gapping tool  1170  is configured to define a distance  1184  which is based on a desired offset between the y-connector  1182  and the on-device adapter  1182  that provide the amount of throw the on-device adapter should have when being loaded into the robotic drive. First, the distal tip  1178  of the EMD  1173  is substantially aligned with the distal tip  1180  of the catheter  1176  as shown in  FIG. 121 . When the distal tip  1178  of the EMD  1174  and the distal tip  1180  of the catheter  1176  are aligned the gapping tool may be positioned next to the EMD  1174  to indicate the proper position or offset of the on-device adapter on the EMD  1174  from the y-connector  1182  of the catheter  1176  (i.e., the device into which the EMD  1174  is being actuated). In an embodiment, the gapping tool  1170  may be adjustable so that the distance  1184  (or gap) may be adjusted based on parameters of the catheter-based procedure system, for example, parameters of the robotic drive. 
     In another embodiment, the gapping tool may be configured to position or align an on-device adapter based on the lengths of the EMDs and other devices (e.g., a length of a y-connector).  FIG. 122  is a schematic diagram of an elongated medical device, a gapping tool and an on-device adapter in accordance with an embodiment. In this embodiment, the positon of an on-device adapter from either end (the proximal end or the distal end) of the EMD  1192  (e.g., a wire-based EMD) may be calculated based on the length of the catheter (not shown) into which the EMD is being position, the length of the EMD  1192  and other parameters such as, for example, the length of a y-connector of the catheter). In  FIG. 122 , the gapping tool  1190  is shown positioned next to and along the EMD  1192  and used to position the on-device adapter  1194  from a proximal end  1196  of the EMD  1192 . Gapping tool  1190  is configured to be adjustable to change the desired offset for the on-device, for example, based on parameters of the catheter-based procedure system such as parameters of the robotic drive. For example, gapping tool  1190  may include a scale  1198  and a slide  1197  that may be moved to adjust the distance (or gap)  1195  defined by the gapping tool  1180 . Because the gapping tool  1190  is configured to position or align an on-device adapter based on known lengths of the EMDs, gapping tool  1190  may be used to position the on-device adapter  1194  on the EMD  1192  before the EMD is positioned in a catheter in the vasculature. In another embodiment, the gapping tool may be configured to resemble a custom tape measure.  FIG. 123  is a diagram of an example gapping tool in accordance with an embodiment. Gapping tool  1200  includes a scale  1202 . The scale  1202  may be shifted to account for the desire throw, length of the hub and y-connector, etc. In an embodiment, the scale  1202  may be read in cm of catheter length. In  FIG. 123 , the gapping tool  1200  is shown positioned net to an EMD  1204  with an on-device adapter  1206 . In another embodiment, the tape measure form of the gapping tool may be configured in a spiral shape as shown in  FIG. 124 . The spiral shape of the gapping tool  12010  with scales  1212  may improve usability of the gapping tool  1210 . The gapping tool  1210  may be unwound when needed to be positioned along the EMD to position an on-device adapter on the EMD. 
     Computer-executable instructions for robotic interventional procedures according to the above-described methods may be stored on a form of computer readable media. Computer readable media includes volatile and nonvolatile, removable, and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer readable media includes, but is not limited to, random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), flash memory or other memory technology, compact disk ROM (CD-ROM), digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired instructions and which may be accessed by system  10  (shown in  FIG. 1 ), including by internet or other computer network form of access. 
     A control computing system as described herein may include a processor having a processing circuit. The processor may include a central purpose processor, application specific processors (ASICs), circuits containing one or more processing components, groups of distributed processing components, groups of distributed computers configured for processing, etc. configured to provide the functionality of module or subsystem components discussed herein. Memory units (e.g., memory device, storage device, etc.) are devices for storing data and/or computer code for completing and/or facilitating the various processes described in the present disclosure. Memory units may include volatile memory and/or non-volatile memory. Memory units may include database components, object code components, script components, and/or any other type of information structure for supporting the various activities described in the present disclosure. According to an exemplary embodiment, any distributed and/or local memory device of the past, present, or future may be utilized with the systems and methods of this disclosure. According to an exemplary embodiment, memory units are communicably connected to one or more associated processing circuit. This connection may be via a circuit or any other wired, wireless, or network connection and includes computer code for executing one or more processes described herein. A single memory unit may include a variety of individual memory devices, chips, disks, and/or other storage structures or systems. Module or subsystem components may be computer code (e.g., object code, program code, compiled code, script code, executable code, or any combination thereof) for conducting each module&#39;s respective functions. 
     This written description used examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims. The order and sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. 
     Many other changes and modifications may be made to the present invention without departing from the spirit thereof. The scope of these and other changes will become apparent from the appended claims.