Abstract:
A patient transfer system is provided to move a patient between modalities. The system includes a deploying modality having a top surface configured to support the patient; a patient transfer support positionable on the top surface of the deploying modality, the patient transfer support also being configured for movement from the top surface of the deploying modality to a top surface of the receiving modality; a patient transfer support locating feature positionable to limit movement of the patient transfer support relative to the top surface of the receiving modality; and a keying feature positionable to engage at least one of a surface associated with the receiving modality or a surface of the patient transfer support, the keying feature being configured to inhibit movement of the patient transfer support in at least one direction relative to the top surface of the receiving modality. The patient transfer support locating feature limits the range of movement of the patient transfer support relative to the top surface of the receiving modality when the patient transfer support is moved from the top surface of the deploying modality to the top surface of the receiving modality.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of the earlier filed U.S. Provisional Application No. 62/027,284, titled “PATIENT TRANSFER SURFACE LOCATING DEVICE,” filed on Jul. 22, 2014, the contents of which are incorporated by reference herein. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Various treatment and imaging procedures require accurate positioning and repositioning of patients to ensure optimum results and outcomes. For example, radiation therapy requires accurate positioning and repositioning of patients in order to ensure that the radiation dose is delivered to the tumor and spares healthy tissue. A constant need exists among patient transport system manufacturers to develop patient transport systems and related systems and accessories that are cost-effective and/or include improved features/structures. Thus, a need exists for improved patient transport systems and related assemblies/accessories. 
       SUMMARY OF THE INVENTION 
       [0003]    According to one aspect of the invention, a patient transfer support locating device is provided comprising a bar having a top surface and a bottom surface; at least one bottom locating feature extended below the bottom surface of the bar; at least one top locating feature extended above the top surface of the bar; wherein the at least one bottom locating feature is configured to engage an indexing feature on a treatment or imaging couch top and the at least one top locating feature is configured to engage an indexing feature on a patient transfer support. 
         [0004]    The device may include a safety stop on the top surface of the bar configured to prevent the patient transfer support from sliding past the imaging or treatment couch top. The top locating feature may be configured to prevent the patient transfer support from sliding past the imaging or treatment couch top, and the at least one top locating feature may be configured such that the locating feature is larger nearer the bar and decreases in size further from the bar. Also, the at least one top locating feature may be a tapered pin such that the diameter of the pin is larger nearer the bar and decreases in size further from the bar. The at least one bottom locating feature may be a disc that engages a crescent-shaped indentation in the couch top. 
         [0005]    The device may include a keying feature wherein the top locating feature is configured to locate the patient transfer support in the superior and inferior direction and the keying feature is configured to locate the patient transfer support in the lateral and medial direction. The keying feature may also be tapered. 
         [0006]    The device may be constructed from MRI compatible materials, and it may include a first bottom locating feature and a second bottom locating feature, the first bottom locating feature having a dissimilar geometry to the second bottom locating feature. 
         [0007]    According to another aspect of the invention, a method is provided for transferring a patient to an imaging or treatment modality. The method includes indexing a patient transfer support locating device onto an imaging or treatment modality; transferring a patient transfer support transversely to an imaging or treatment modality; and indexing the patient transfer support to the patient transfer support locating device. 
         [0008]    According to yet another aspect of the invention, a patient transfer support locating device is provided including at least one bar adapted for placement on a couch top. The at least one bar includes at least one top locating feature extending upward with respect to the bar, the at least one top locating feature having a geometry configured to match an indexing feature on a patient transfer support, and at least one keying feature configured to restrict lateral movement of the patient transfer support when the patient transfer support is positioned on the treatment couch top; wherein the patient transfer support is indexed to the couch top when the patient transfer support is moved laterally with respect to the treatment couch top such that the patient transfer support indexing feature engages the at least one top locating feature. 
         [0009]    The at least one bar may include at least one bottom locating feature extending downward with respect to the bar, the at least one bottom locating feature having a geometry configured to match an indexing feature on the couch top. The at least one keying feature optionally comprises a pin, and the at least one keying feature may restrict lateral movement of the patient transfer support when the at least one keying feature is inserted into a channel formed in the patient transfer support. The at least one keying feature is optionally inserted into the channel when the patient transfer support is lowered onto the at least one bar. The patient transfer support is optionally lowered onto the at least one bar upon deflation of an air bladder attached to a bottom side of the patient transfer support. The at least one keying feature may extend upward with respect to the bar. And the at least one top locating feature optionally extends upward with respect to the bar to a distance greater than the extension of the at least one keying feature, thereby permitting indexing of the patient transfer support to the treatment couch top prior to insertion of the at least one keying feature into the channel. 
         [0010]    According to still another aspect of the invention, a method of locating a patient transfer support to a treatment couch top is provided, comprising placing a patient transfer support locating device with at least one bar on the treatment couch top; moving the patient transfer support over the treatment couch top; aligning at least one top locating feature extending upward with respect to the at least one bar to an indexing feature formed on the patient transfer support; and engaging the indexing feature on the patient transfer support with the at least one top locating feature. 
         [0011]    The placing step may include aligning at least one bottom locating feature extending downward with respect to the at least one bar to an indexing feature formed on the treatment couch top. The method may include inserting at least one keying feature on the at least one bar into a channel formed in the patient transfer support. The inserting step may further include lowering the patient transfer support to the treatment couch top. Additionally, the inserting step may also include deflating an air bladder attached to a bottom surface of the patient transfer support, thereby lowering the channel over the at least one keying feature. 
         [0012]    According to another aspect, the invention provides a treatment couch top including a top surface configured to receive a patient transfer support thereon, the top surface including at least one top locating feature the at least one top locating feature having a geometry configured to match an indexing feature on the patient transfer support, and at least one keying feature configured to restrict lateral movement of the patient transfer support when the patient transfer support is positioned on the treatment couch top. The patient transfer support is indexed to the treatment couch top when the patient transfer support is moved laterally with respect to the treatment couch top such that the patient transfer support indexing feature engages the at least one top locating feature, and the patient transfer support is restricted from lateral movement with respect to the treatment couch top when the at least one keying feature engages a channel formed in the patient transfer support. 
         [0013]    The at least one top locating feature and the at least one keying feature are optionally formed on a bar on the top surface of the treatment couch top. The bar can be removably attached to the treatment couch top. 
         [0014]    The treatment couch top can also include at least one indexing feature adapted to engage at least one bottom locating feature formed on a bottom surface of the patient transfer support. The at least one keying feature optionally engages the channel formed in the patient transfer support when an air bladder attached to a bottom surface of the patient transfer support is deflated. 
         [0015]    According to another aspect of the invention, a patient transfer system is configured to move a patient between modalities. The system includes a deploying modality configured to be positioned adjacent a receiving modality, the deploying modality having a top surface configured to support the patient; a patient transfer support configured to support the patient, the patient transfer support being positionable on the top surface of the deploying modality, the patient transfer support also being configured for movement from the top surface of the deploying modality to a top surface of the receiving modality; a patient transfer support locating feature configured to extend upwardly relative to the top surface of the receiving modality and positionable to limit movement of the patient transfer support relative to the top surface of the receiving modality; and a keying feature extending downwardly from the patient transfer support or configured to extend upwardly relative to the top surface of the receiving modality, the keying feature being positionable to engage at least one of a surface associated with the receiving modality or a surface of the patient transfer support, the keying feature being configured to inhibit movement of the patient transfer support in at least one direction relative to the top surface of the receiving modality; wherein the patient transfer support locating feature limits the range of movement of the patient transfer support relative to the top surface of the receiving modality when the patient transfer support is moved from the top surface of the deploying modality to the top surface of the receiving modality. 
         [0016]    The keying feature can be configured to extend upwardly from the top surface of the receiving surface and to engage a surface of the patient transfer support. 
         [0017]    The patient transfer support optionally includes an inflatable bladder or cushion to facilitate movement of the patient transfer support relative to the top surface of the receiving modality. The keying feature can be configured to inhibit movement of the patient transfer support in the at least one direction relative to the top surface of the receiving modality when the inflatable bladder or cushion is deflated, and wherein the keying feature is not configured to engage the surface of the patient transfer support or the surface associated with the receiving modality when the inflatable bladder or cushion is inflated. The patient transfer support locating feature can be configured to extend upwardly from the top surface of the receiving modality is positionable to limit movement of the patient transfer support relative to the top surface of the receiving modality both when the inflatable bladder or cushion is inflated and deflated. 
         [0018]    The patient transfer system can also include a patient transfer support locating device configured to be associated with the top surface of the receiving modality. The patient transfer support locating feature can extend from the patient transfer support locating device. The patient transfer support locating device can include a receiving modality locating feature positioned to limit movement of the patient transfer support locating device relative to the top surface of the receiving modality. The receiving modality locating feature extends downwardly relative to the top surface of the receiving modality. 
         [0019]    The deploying modality can be a transport modality configured to transport the patient to the receiving modality. Also, the transport modality can be a trolley. Additionally, the receiving modality can be an image or treatment modality, and the image or treatment modality can be a couch. 
         [0020]    The keying feature is optionally positionable to engage the surface of the patient transfer support. The patient transfer support locating feature optionally prevents movement of the patient transfer support in at least one direction relative to the top surface of the receiving modality beyond a limit. 
         [0021]    According to another aspect, this invention provides a method of transferring a patient between modalities, the method includes positioning a patient transfer support on a top surface of a deploying modality; positioning the patient on a top surface of the patient transfer support; inflating a bladder or cushion of the patient transfer support and raising the top surface of the patient transfer support relative to the top surface of the deploying modality; moving the patient transfer support and the patient from the top surface of the deploying modality to a top surface of a receiving modality; limiting movement of the patient transfer support relative to the top surface of the receiving modality with a patient transfer support locating feature extending upwardly relative to the top surface of the receiving modality, wherein the patient transfer support locating feature limits the range of movement of the patient transfer support relative to the top surface of the receiving modality when the patient transfer support is moved from the top surface of the deploying modality to the top surface of the receiving modality; deflating the bladder or cushion of the patient transfer support, thus lowering the top surface of the patient transfer support relative to the top surface of the receiving modality; and inhibiting movement of the patient transfer support in at least one direction relative to the top surface of the receiving modality with a keying feature extending downwardly from the patient transfer support or upwardly relative to the top of the receiving modality by engaging a surface of the receiving modality or a surface of the patient transfer support with the keying feature. 
         [0022]    The keying feature can inhibit movement of the patient transfer support in the at least one direction relative to the top surface of the receiving modality when the inflatable bladder or cushion is deflated, and the keying feature may not engage the surface of the patient transfer support or the top surface of the receiving modality when the inflatable bladder or cushion is inflated. The patient transfer support locating feature optionally limits movement of the patient transfer support relative to the top surface of the receiving modality when the inflatable bladder or cushion is inflated and the top surface of the patient transfer support is raised relative to the top surface of the receiving modality. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  is an isometric view of a patient transfer support locating device according to an embodiment of the invention; 
           [0024]      FIG. 2  is an end view of a patient transfer support locating device according to an embodiment of the invention; 
           [0025]      FIG. 3  is an isometric view of an embodiment of a system according to the invention including patient transfer support locating devices installed on a treatment couch top; 
           [0026]      FIG. 4  is a plan view of the system of 
           [0027]      FIG. 5  including patient transfer support locating devices installed on a treatment couch top; to the invention including a patient transfer support located on a treatment couch top using patient transfer support locating devices; 
           [0028]      FIG. 6  is a side view of the system of  FIG. 5  including a patient transfer support located on a treatment couch top using patient transfer support locating devices; 
           [0029]      FIG. 7  is an isometric view of an embodiment of yet another system according to the invention including a patient transfer support on a trolley which is in proximity to an imaging couch top, the imaging couch top having patient transfer support locating devices installed; 
           [0030]      FIG. 8  is an isometric view of another embodiment of a patient transfer support locating device of the invention; 
           [0031]      FIG. 9  is an isometric view of another embodiment of a patient transfer support locating device according to aspects of the invention; 
           [0032]      FIG. 10  is an isometric view of an embodiment of a system including a treatment couch top and patient transfer support locating devices of  FIG. 9 ; 
           [0033]      FIG. 11  and  FIG. 12  depict a patient transfer support being moved with respect to a treatment couch in accordance with aspects of the invention; 
           [0034]      FIG. 13  and  FIG. 14  are cross-sectional views showing a transfer support being lowered with respect to a treatment couch top according to aspects of the invention; 
           [0035]      FIG. 15  and  FIG. 16  are side views of additional embodiments of patient transfer support locating devices in accordance with aspects of the invention; 
           [0036]      FIG. 17  and  FIG. 18  are isometric cross-sectional views of an embodiment of a patient transfer support with an air bladder attached in accordance with aspects of the invention; 
           [0037]      FIG. 19  and  FIG. 20  are cross-sectional views of a patient transfer support with an air bladder being lowered with respect to a treatment couch top according to aspects of the invention; 
           [0038]      FIGS. 21A, 21B, 22A and 22B  are cross-section views of a patient transfer support engaging locating devices in according to aspects of the invention; 
           [0039]      FIGS. 23 and 24  are top views of embodiments of treatment couch tops in accordance with aspects of the invention; 
           [0040]      FIG. 25  is a front view of a patient transfer support according to aspects of the invention; 
           [0041]      FIG. 26  is a cross-sectional view of the patient transfer support of  FIG. 26 ; and 
           [0042]      FIG. 27  is an isometric view of the patient transfer support of  FIGS. 25 and 26  being moved with respect to a treatment couch top in accordance with aspects of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0043]    The exemplary embodiments disclosed herein are illustrative of advantageous systems/assemblies of the present disclosure and methods/techniques thereof. It should be understood, however, that the disclosed embodiments are merely exemplary of the present disclosure, which may be embodied in various forms. Therefore, details disclosed herein with reference to exemplary patient transfer support locating devices or fabrication methods and associated processes or techniques of assembly and use are not to be interpreted as limiting, but merely as the basis for teaching one skilled in the art how to make and use the advantageous assemblies/systems and/or alternative assemblies/systems of the present disclosure. 
         [0044]    Some equipment used today for diagnostic imaging and cancer treatment is sophisticated and expensive. To attempt to maximize the utilization of this equipment it is desirable to transport a patient to and from the equipment on a transport system/assembly which allows rapid change over from one patient to the next. 
         [0045]    Moreover, some procedures require a rapid transition from one type of equipment to the next. More specifically, it may be desirable to transfer a patient between modalities (e.g., from a deploying modality to a receiving modality). As such, there are instances in which a patient is taken from one imaging modality (e.g., CT, PET, CT, MRI, etc.) to another or from an imaging modality to the treatment room in succession. For example, it is often desirable to perform positron emission tomography/computed tomography (PET/CT) and magnetic resonance imaging (MRI) exams in close time proximity so that the biological effect of interest can be seen in both machines. An effective patient transport system can be a significant aid in such situations. 
         [0046]    Radiation therapy and diagnostic imaging equipment are often used in hospitals and treatment centers. Some techniques for radiation therapy and diagnostic imaging require that patients be positioned and immobilized precisely. Generally, treatment of a tumor by radiation therapy is preceded by a diagnostic imaging procedure called simulation. During simulation, the patient is positioned in the manner anticipated for treatment. This can include the physical orientation of the patient using the positioning and immobilization devices that will be used in treatment. 
         [0047]    Furthermore, some state of the art cancer radiation therapy is increasingly based on the pinpoint application of high-energy radiation, which can be highly tailored to the shape and position of the cancerous tumor. As the size of the treatment beam decreases, the accurate location of the beam becomes much more critical. For example, if a highly tailored treatment beam is off target (e.g., by a few millimeters), it may miss the tumor. Because of these new techniques, it becomes increasingly desirable to know the location/shape of the tumor accurately when the patient is positioned for treatment. 
         [0048]    The present disclosure provides improved patient transfer support locating devices, and related methods of use. More particularly, the present disclosure provides indexable positioning of a patient transfer support with reference to an imaging or treatment couch top. For example, the device may be used to locate a patient transfer support for diagnostic imaging (e.g., CT, MRI, PET/CT, PET/MRI) and/or radiation therapy applications (e.g., photon, proton, brachytherapy), although the present disclosure is not limited thereto. Rather, it is noted that the device of the present disclosure can be used for a wide variety of purposes/treatments/applications. 
         [0049]    In certain embodiments, the device of the present disclosure is configured and dimensioned to be utilized with a variety of imaging and/or treatment modalities/environments. As such, the target imaging or treatment assemblies/surfaces that the device may be used with may include many different types of equipment/surfaces (e.g., radiation therapy treatment tables/surfaces, CT tables/surfaces, MRI tables/surfaces, brachytherapy tables/surfaces, etc.). 
         [0050]    Current practice provides that it is important that the patient be simulated in substantially the same position on the assemblies/devices as will be used in treatment to attempt to ensure accurate tumor location for treatment. Accurate tumor location and treatment spares the surrounding healthy tissue. This positioning and/or immobilization process can be extensive and time consuming. It can be beneficial, therefore, to set up the patient beforehand outside the room containing the actual treatment or imaging equipment to better utilize time on the treatment or imaging equipment. In some cases, imaging and treatment are done on the same day. In these cases it can be beneficial to set up the patient once and have them remain positioned/immobilized throughout the imaging and/or treatment procedures. When transporting patients from one piece of equipment to another it is generally desirable to employ an efficient and easy-to-use patient transfer system, as such a system can provide for the safe and efficient transfer of a patient from one target modality/surface to another. It is noted that the easy and safe transfer is beneficial for both the patient and the operator moving the patient. 
         [0051]    In illustrative embodiments, the present disclosure provides for improved and easy-to-use locating of a patient transfer support with respect to an imaging or treatment couch top, thereby providing a significant operational, commercial and/or manufacturing advantage as a result. Moreover, by utilizing the devices of the present disclosure for imaging/treatment the users (e.g., hospitals and treatment centers) can experience improved utilization of equipment and higher patient throughput, which in turn can lower costs and provide improved/faster patient care. Furthermore, illustrative devices of the present disclosure provide that the patient can be repeatably positioned and/or immobilized precisely, thereby providing a significant clinical advantage as a result. 
         [0052]    Furthermore, the device of the present disclosure provides for the efficient use of imaging and treatment equipment by enabling set-up of the patient on the positioning/immobilization assembly/device in a separate room, thereby leaving the treatment equipment free until needed. 
         [0053]    The present disclosure provides devices that are configured to accurately, safely, and repeatably locate a patient transfer support for various diagnostic imaging and treatment applications/environments (e.g., diagnostic imaging, high-energy radiation therapy, image guided surgery, operating room, interventional procedures, general medical procedures, trauma and emergency medical services). 
         [0054]    In illustrative embodiments, the patient transport systems/assemblies of the present disclosure are configured and dimensioned to be utilized with a wide variety of imaging and/or treatment modalities/environments. For example, the target treatment assemblies/surfaces that the patient may be transferred to and/or from (via the improved patient transport assemblies/systems of the present disclosure) can include many different types of equipment/surfaces (e.g., radiation therapy treatment, CT, MRI and/or brachytherapy equipment/tables/surfaces, interactive robotic surfaces, transport devices, etc.). 
         [0055]    The present disclosure provides for the accurate, safe, and repeatable positioning of patients utilizing the indexing features of the couch top of the imaging or treatment modality such as crescent-shaped indentations on the perimeter of the couch top as described in U.S. Pat. No. 5,806,116, which is incorporated by reference herein. Although this is the most common configuration of these indexing features, the present invention can be applied to any indexing scheme known to one skilled in the art. The present disclosure illustrates embodiments including a bar that is configured to be positioned in these indexing features using at least one bottom locating feature attached to or extending from the bottom surface of the bar. The device also provides at least one top locating feature attached to or extending from the top surface of the bar which may be configure to interface with at least one indexing feature of a patient transfer support. One or more features located on the top surface of the bar may be configured to accurately and repeatedly locate the patient transfer support with respect to the couch top. In illustrative embodiments, one or more features extending from the top surface of the bar may be configured to act as a safety stop which prevents the patient transfer support from being moved past the couch top. This feature reduces the burden on hospital staff to ensure that a patient is not injured during transfer to the imaging or treatment modality. 
         [0056]    Referring now to the drawings, like parts are marked throughout the specification and drawings with the same reference numerals, respectively. Drawing figures are not necessarily to scale and in certain views, parts may have been exaggerated for purposes of clarity. 
         [0057]    Referring to the figures generally, the invention provides patient transfer support locating devices, such as devices  100 ,  800 ,  900 ,  1200 ,  1300 , and  1500 . The locating devices may be used to locate a patient transfer support, such as surfaces  510 ,  1100 ,  1400 ,  2000 , and  2500 , to an imaging or treatment modality that can be in the form of treatment couch tops, such as couch tops  310 ,  730 ,  1000 ,  1508 ,  2300 ,  2400 , and  2600 . The locating devices generally include at least one top locating feature, such as features  106 ,  804 ,  902 ,  1202 ,  1302 , and  1502 , as well as at least one bottom locating feature, such as features  104 ,  806 ,  904 , and  1204 . The locating devices may also include at least one keying feature, such as keying features  802 ,  906 ,  1206 ,  1306 , and  1506 . The keying feature and top locating feature are optionally provided on the same or separate components of the system. For example, the locating device may include the keying feature and the top locating feature. Alternatively, the keying feature and/or the top locating feature can be provided on another surface or component associated with a modality. 
         [0058]    The top locating features may be adapted to engage indexing features formed on the patient transfer support (e.g., indexing features  512  and  1101 ). Furthermore, the bottom locating features may be adapted to engage indexing features formed on the treatment couch top (e.g., features  312  and  1002 ). The engagement and alignment of the aforementioned locating features and indexing features allow for location of the patient transfer supports with respect to the treatment couch tops. 
         [0059]    Additionally, the patient transport surfaces may include channels, such as channels  1102  and  1510  that are adapted to receive the keying features of the locating devices. When the keying features are inserted into the channels, the lateral and medial movement of the transfer supports with respect to the couch tops is restricted. The insertion may be accomplished by lowering the transfer supports with respect to the couch tops when the transfer supports are aligned and indexed to the couch tops. The insertion may also be accomplished by raising the keying feature into the channel of the transfer support. 
         [0060]    With reference to  FIG. 1  and  FIG. 2  the patient transfer support location device  100  comprises a bar  102 , at least one bottom locating feature  104  and at least one top locating feature  106 . The top locating feature  106  and bottom locating feature  104  may be an integral feature of the bar  102  or may be removably or permanently attached to the bar  102 . For example, the bar  102 , bottom locating feature  104 , and top locating feature  106  could all be machined or otherwise formed from a single piece of material. Alternatively, these could be separate pieces that are screwed, snapped, bonded together, clamped, or otherwise fastened. The bar  102  is configured to span the width of a treatment or imaging modality such as a couch top (not shown). Couch tops typically used in radiation therapy are approximately 530 mm wide. The at least one bottom locating feature  104  is configured to engage indexing features on the imaging or treatment couch top. The most common form of indexing found in radiation therapy is crescent-shaped indentations running along the sides of the couch top. The at least one bottom locating feature  104  can be configured to engage this type of indexing or any other indexing scheme which will be understood to one skilled in the art from the description herein. In one embodiment, the at least one bottom locating feature  104  is manufactured from a compliant material such that a press-fit is established between the locating feature and the indexing on the couch top. Alternatively, a cam may be used to tightly engage the locating features with the indexing features. Further, a spring biased mechanism may be used to engage the indexing features. 
         [0061]    The top locating feature  106  is configured to engage with indexing features on a patient transfer support. These indexing features may be the same form of indexing used on the couch top or may be a different indexing configuration. In this embodiment the top locating feature  106  is tapered such that it is larger nearer the bar  102  and decreases in size as it moves away from the bar  102 . This is done to make it easier for the user to engage the locating feature when transferring a patient. As shown in  FIG. 1  and  FIG. 2 , the top locating feature  102  is configured to engage crescent-shaped indexing features. Although only one bar  102 , one bottom locating feature  104  and one top locating feature  106  are depicted in  FIGS. 1 and 2 , it is contemplated that multiple bars and bars with multiple top and/or bottom locating features may be utilized to effectuate the invention. 
         [0062]    In  FIG. 3  and  FIG. 4  a treatment couch top  310  is shown with two patient transfer support location devices  100  in place, thus forming a patient transfer system according to an embodiment of this invention. The patient transfer support location devices are positioned using indexing features  312 . The indexing features  312  on the couch top  310  are configured to match the geometry of the bottom locating features on the bar  102 . As shown in the  FIGS. 3 and 4 , the indexing features  312  are of a crescent shape that is configured to match the geometry of the bottom locating features. Those of skill in the art will understand other suitable geometries suitable for matching indexing features with top locating features from the description herein. Any number of the patient transfer supports may be installed on a couch top  310 . In a preferable configuration two of the devices  100  are used. These can be located in any of the indexing features  312  on the couch top  310 . They may be spaced a sufficient distance apart to prevent rotation of a patient transfer support with respect to the couch top  310 . 
         [0063]      FIG. 5  and  FIG. 6  show a patient transfer support  510  positioned on a treatment couch top  310 , thus forming a patient transfer system according to another aspect of this invention. The indexing features  512  of the patient transfer support  510  are engaged with the top locating feature  106  of the patient transfer support locating device  100 . As can be seen in these figures, the top locating features  106  can be configured to additionally serve as safety stops to prevent the patient transfer support  510  from sliding off of the couch top  310  as it is moved from left to right on the couch top  310 . Alternatively, the safety stop can be accomplished with an additional feature, separate from the top locating feature  106 . In order to change the configuration such that the patient transfer support  510  may be slid from the right side of the couch top  310 , the patient transfer support locating devices  100  may be rotated 180 degrees with respect to the couch top. 
         [0064]    With reference to  FIG. 7 , the present invention is shown in use on an imaging couch top  730 , thus forming a patient transfer system according to another aspect of this invention. A transport modality such as trolley  720  is brought in proximity to an imaging or treatment modality such as an imaging couch top  730  which is supported by an imaging couch  710 . The patient transfer support  510  is shown on the trolley  720 . After the trolley  720  is placed in close proximity to the couch top  730 , the patient transfer support  510  may be moved from the trolley  720  to the couch top  310  by sliding transverse to the long axis of the couch top  730 . As the patient transfer support  510  is moved laterally the indexing feature  512  will come into contact with the top locating feature  106  of the patient transfer support locating device  100  which is aligned to the corresponding indexing feature  512 . This will locate the patient transfer support  510  with respect to the couch top  730 . 
         [0065]    A second embodiment of the patient transfer support locating device  800  is shown in  FIG. 8 . A top locating feature  804  is configured to engage with indexing features located along the perimeter of a patient transfer support. For example, the top locating feature may be configured to engage crescent-shaped indexing features as shown in previous figures. A keying feature such as a pin  802  is configured to engage a feature on the patient transfer support. For example, a channel (not shown) can be located in or on the bottom surface of the patient transfer support to engage the keying feature  802 . This channel can be oriented with the axis of the channel substantially parallel to the long axis of the patient transfer support. In this way the top locating feature  804  locates the patient transfer support in the longitudinal axis (superior/inferior direction) and the keying feature  802  locates the patient transfer support in the transverse axis (medial/lateral direction). The keying feature  802  shown in  FIG. 8  is a round pin but can be any shape that effectively locates the patient transfer support.  FIG. 8  shows the keying feature  802  in the center of the bar but it may be located anywhere along the bar. 
         [0066]      FIGS. 9-12  depict another embodiment of a patient transport locating device  900 . The locating device  900  includes a bar  901 , a top locating feature  902 , a bottom locating feature  904 , and a keying feature  906 . The top locating feature  902  and the keying feature  906  extend upward with respect to the bar  901 , while the bottom locating feature  904  extends downward with respect to the bar  901 . In this embodiment, the keying feature  906  is positioned closer to the top locating feature  902  along the bar  901 . The keying feature  906  is depicted as a cylindrical pin. However, other suitable keying features will be understood by those of skill in the art from the description herein. 
         [0067]      FIG. 10  shows a treatment couch top  1000  with the locating devices  900  positioned on the treatment couch top  1000 . The treatment couch top  1000  includes indexing features  1002  similar to the indexing features described above. 
         [0068]    In  FIG. 11  and  FIG. 12 , a patient transfer support  1100  is shown being positioned over the treatment couch top  1000 . The patient transfer support  1100  includes indexing features  1101  formed on the patient transfer support  1100  that have a geometry to match the geometry of the top locating features  902  of the locating device  900  such that the indexing features  1101  can engage the top locating features  902 . Formed on the patient transfer support  1100  are channels such as apertures or recesses  1102  that are adapted to receive the keying features  906  of the device  900 . Thus, as shown in  FIG. 12 , when the patient transfer support  1100  is slid or moved laterally over the treatment couch top  1000 , the indexing features  1101  engage the top locating features  902 . 
         [0069]    The top locating features (and/or other top locating features described herein) extend upwardly to a height that is sufficiently above the top surface of the patient transfer support such that when the patient transfer support is raised, the indexing features engage the top locating features and the patient transfer support does not get moved over or past the top locating features. In one example, the patient transfer support may be keyed to the treatment couch top by simply lowering the patient transfer support to the treatment couch top once the indexing features are engaged to the top locating features (e.g., utilizing gravity to key the surfaces without the use of clamps, vices, or other affixing mechanisms). Thus, the keying features restrict movement of the patient transfer support in the x and y directions, while gravity restricts movement of the patient transfer support in the z direction. 
         [0070]    Cross sectional views of the patient transfer support  1100  being located to the treatment couch top  1000  are shown in  FIGS. 13 and 14 . At  FIG. 13 , the patient transfer support  1100  is indexed to the top locating feature  902 , but is elevated with respect to the treatment couch top  1000 . When the patient transfer support  1100  is lowered to the treatment couch top  1000 , the keying feature  906  is inserted into the channel  1102 . The insertion of the keying feature  906  into the channel  1102  restricts lateral and medial movement of the transfer support  1100  with respect to the couch top  1000 . 
         [0071]    Other examples of locating devices are shown in  FIGS. 15 and 16 . For example, the locating device  1200  includes a keying feature  1206  that is tapered, increasing the upward extension with respect to the bar  1201  as it approaches the top locating feature  1202 . The keying feature  1206  is positioned closer to the top locating feature  1202  and farther from the bottom locating feature  1204 . The keying feature  1206  is configured to engage an opening formed on the bottom of a patient transfer support (not shown) such that lateral movement of the patient transfer support is restricted with respect to the treatment top when the keying feature engages the opening. 
         [0072]    A further example of a locating device is depicted at  FIG. 16 . The locating device  1300  includes a keying feature  1306  that is in the form of a flange biased upward by a spring  1308 . As a patient transfer support is moved toward the locating feature  1302 , the transfer support pushes the keying feature  1306  downward. The spring  1308  biases the keying feature  1306  upward into a channel formed on the bottom of the transfer support, thereby preventing lateral movement of the patient transfer support with respect to the treatment top. 
         [0073]    Another example of a patient transfer support  1400  is depicted in  FIGS. 17 and 18 . The patient transfer support  1400  includes a top surface  1402  adapted to support a patient thereon. The transfer support  1400  also includes edges  1404 . Indexing features (not shown) may be formed along the edges  1404 . Attached to the bottom of the transfer support  1400  is an air bladder  1406 . The air bladder  1406  as depicted includes a top skin  1408  and a bottom skin  1410 . As shown in  FIG. 18 , when the air bladder  1406  is inflated, the position of the transfer support  1400  with respect to the surface upon which it is placed is elevated. The air bladder  1406  is configured to facilitate movement of the transfer support  1400  to a couch top. 
         [0074]      FIGS. 19 and 20  depict utilization of a keying feature with a transfer support  1400  equipped with an air bladder  1406 . The transfer support  1400  is positioned over a treatment couch top  1508 , and is indexed to the top locating feature  1502  of the locating device  1500 . In  FIG. 19 , the air bladder  1406  is inflated, thereby elevating the patient transfer support  1400  with respect to the treatment couch top  1508 . The indexing of the transfer support  1400  to the top locating feature  1502  aligns a channel  1510  formed near or on one of the edges  1404  of the transfer support  1400  over the keying feature  1506  of the device  1500 . As shown in  FIG. 20 , when the air bladder  1406  is deflated, the patient transfer support  1400  approaches the treatment couch top  1508 , thereby lowering the transfer support  1400  with respect to the couch top  1508 . The lowering of the transfer support  1400  causes the keying feature  1506  to be inserted into the channel  1510 . The insertion of the keying feature  1506  into the channel  1510  restricts lateral and medial movement of the transfer support  1400  with respect to the couch top  1508 . To remove the keying feature  1506  from the channel  1510 , the air bladder  1406  may be inflated, thereby elevating the transfer support  1400  with respect to the couch top  1508 . 
         [0075]    Other examples of locating a patient transfer support to a treatment couch are shown in  FIGS. 21A-22B . In  FIG. 21A , a patient transfer support  2000  has a channel  2002  formed on the bottom of the transfer support. As the transfer support  2000  is moved over the keying feature  1206  formed on the locating device  1200 , the tapered surface of the keying feature  1206  facilitates movement of the transfer support  2000  over the keying feature  1206 . Once the transfer support  2000  moves sufficiently close to the locating feature  1202 , the keying feature  1206  is engaged with the channel  2002 , as shown in  FIG. 21B . This engagement prevents lateral movement of the transfer support  2000  with respect to a treatment surface. The keying feature  1206  may be removed from the transfer support  2000  by lifting the transfer support  2000  or by a release mechanism (not shown) that lowers the keying feature  1206  from the channel  2002 . 
         [0076]    In  FIG. 22A , the patient transfer support  2000  is moved on the locating device  1300  over the keying feature  1306 , which is a flange type feature that is biased by a spring  1308 . As the transfer support  2000  contacts the keying feature  1306 , it is caused to move downward with respect to the transfer support  2000 . As shown in  FIG. 22B , when the transfer support  2000  is moved close enough to the locating feature  1302 , the spring  1308  biases the keying feature  1306  into the channel  2002 , thereby engaging the keying feature  1306  with the channel. This engagement prevents lateral movement of the transfer support  2000  with respect to a treatment top. To disengage the keying feature  1306  from the channel  2002 , the transfer support  2000  may be lifted, or a release mechanism may be coupled to the keying feature  1306 , which removes the keying feature  1306  from the channel. 
         [0077]    In further embodiments, keying features and locating features may be integrated directly onto the treatment couch top. As shown in  FIG. 23 , the top surface  2302  of the treatment top  2300  has integrated on it top locating features  2304  and keying features  2306 . The keying features depicted are similar to the keying feature  906  described above. Further, in  FIG. 24 , the top surface  2402  of the treatment couch top  2400  has formed on it top locating features  2404  and keying features  2406 . The keying features  2406  are similar to the keying features  1206  and  1306  as described above. 
         [0078]    A further example of a system for locating a transfer support to a treatment top is shown in  FIGS. 25, 26, and 27 . The patient transfer support  2500  has bottom locating features (e.g., bosses)  2504  formed on the bottom surface  2502 . The bottom locating features  2504  are integrated to the patient transfer support  2500 . The bottom locating features  2504  are configured to engage indexing features  2602  that are formed on the treatment couch top  2600 . In addition, keying features may be disposed or integrated directly on the bottom surface of the patient transfer support  2500 , and may be configured to engage channels formed on the top surface of the treatment couch top  2600  when the patient transfer support  2500  is lowered to the treatment couch top  2600 . 
         [0079]    It is contemplated that various configurations may be utilized and such configurations are not limited to the examples described above. For instance, the locating features, either top or bottom locating features, may be formed on a bar removably attached to a treatment top, or may be integrated on either the transfer supports, treatment tops, or both. Similarly, the keying features and indexing features may be removable or integrated into a bar, the transfer supports, the treatment tops, etc. One of ordinary skill in the art will recognize other suitable configurations to effectuate the disclosed invention from the description herein. 
         [0080]    Also disclosed are methods for locating a patient transfer support to a treatment couch top. The methods may include placing a locating device on a treatment couch top. The locating device may be similar to those described above. The locating devices include a bar, a top locating feature and a bottom locating feature. The locating device may be placed on the treatment couch top by aligning the bottom locating feature with indexing features on the treatment couch top. 
         [0081]    The methods may include moving a patient transfer support over the treatment couch top. The patient transfer support may be moved laterally over the treatment couch top. The movement may be facilitated by manual pushing, by rollers, by low friction surfaces, utilization of an air bladder, and air cushion, etc. 
         [0082]    The top locating features are aligned to an indexing feature formed on the patient transfer support. This alignment permits visual confirmation of the indexing. Once the alignment occurs, the indexing feature on the patient transfer support is engaged with the top locating feature. The engagement may be facilitated by matching geometries between the top locating feature and the indexing feature. 
         [0083]    The aforementioned steps for locating a patient transfer support to a treatment couch top are exemplary and not exclusive. One of skill in the art will understand other suitable forming methods according to aspects of the invention from the description herein. Also, subsets of the steps may be performed, and the steps may be completed in various orders. 
         [0084]    For example, in embodiments where an air bladder is utilized, the patient transfer support rests on a trolley or other transport modality, and is elevated upon inflation of the air bladder. Once elevated, the patient transfer support can be moved to a target modality, such as an imaging or treatment modality (e.g., a treatment couch top). Although lateral movement is described above, the patient transfer support may be moved to the target modality in various directions, including longitudinally. The transfer support is moved to the treatment couch top until it hits the top locating features, such that indexing features, if formed on the patient transfer support, engage with the top locating features. Once engaged, the air bladder is deflated, thus lowering the patient transfer support to the treatment couch top. Keying features, whether disposed on the patient transfer support or on the couch top, then are engaged and prevent at least lateral movement of the patient transfer support with respect to the treatment couch top. To disengage the keying features and thereby permit movement of the transfer support with respect to the treatment couch top, the air bladder may then be inflated, thus raising the transfer support with respect to the treatment couch and permitting movement of the patient transfer support with respect to the treatment couch top. The patient transfer support may then be moved to another target modality, such as a trolley. 
         [0085]    While preferred embodiments of the invention have been shown and described herein, it will be understood that such embodiments are provided by way of example only. Numerous variations, changes and substitutions will occur to those skilled in the art without departing from the spirit of the invention. Accordingly, it is intended that the appended claims cover all such variations as fall within the spirit and scope of the invention.