# Patent

## Title
MRI compatible patient trolley

## Abstract

A trolley system configured to transport a patient within an MRI environment includes a patient support portion, a base portion configured for movement relative to a floor, a lift coupled to the patient support portion and the base portion, an electric motor coupled to the lift, and an electric blower coupled to the patient transfer device. The lift is configured to change the elevation of the patient support portion relative to the base portion. The motor is mounted such that the elevation of the motor is fixed relative to base portion. The trolley system is positionable adjacent an MRI apparatus within the MRI environment and the magnetic field of the MRI does not interfere with the operation of the motor or blower. The trolley system may further include a patient transfer device having an air bearing. The blower is configured to deliver air to the air bearing.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of pending application Ser. No. 15/767,715, filed Apr. 12, 2018, which is a U.S. National Phase Application of PCT International Application PCT/US2016/057108, filed on Oct. 14, 2016, which claims the benefit of U.S. provisional patent application entitled “MRI COMPATIBLE PATIENT TROLLEY,” which was filed on Oct. 14, 2015 and assigned Ser. No. 62/241,403, and U.S. provisional patent application entitled “PATIENT TROLLEY AND PATIENT TRANSFER DEVICE,” which was filed on Oct. 14, 2015 and assigned Ser. No. 62/241,400. The entire contents of the foregoing provisional applications are incorporated herein by reference in their entirety.


FIELD OF THE INVENTION
The present invention generally relates to patient trolleys, associated systems, and methods for transporting patients and providing safe transfer of a patient from the patient trolley to a target modality during medical procedures or diagnostic determinations.
BACKGROUND OF THE INVENTION
Patient trolleys are used frequently in hospitals and treatment centers to safely transport patients to various locations within the facility. When the patient requires therapy or diagnostic imaging, the patient trolleys are used to deliver the patient in proximity to certain target modalities. Target modalities may include various patient support surfaces associated with machines, such as CT, MR, and PET, an operating table, a hospital bed, an OR table, a treatment machine, robotic surgical arms, etc. Patient trolleys are expected to safely transport a patient to and from various target modalities. Often these patients must be immobilized to maintain positional accuracy and consistency from one modality to the next.
In order to transfer a patient from the top surface of a patient trolley to the surface of a target modality, patient transfer devices are commonly used. For patients that are not ambulatory and are expected to remain lying down, including in supine, prone, or recumbent positions, patient trolley operators should transport the patient trolley to a location that is as close as possible to the surface of the target modality. Additional adjustments can be made by lifting or raising the elevation of the top surface of the patient trolley and transferring the patient using the patient transfer device by sliding the patient transfer device from the top surface of the patient trolley to the top surface of the target modality. MRI environments in particular present obstacles to the use of a patient trolley and transfer device. Due to the tremendous strength of the magnetic field generated by an MRI machine, ferromagnetic materials can present a hazard in an MRI environment and therefore are carefully monitored and typically limited, complicating the construction of any device for use in and around the MRI machine.
Thus, a need exists for improved patient trolleys that not only provide safe transport of patients, but also facilitate easier patient transfer to target modalities within an MRI environment. These and other needs are addressed by the patient trolley and associated systems and methods of the present invention.
SUMMARY OF THE INVENTION
In one aspect of the present invention, a trolley system configured to transport a patient within an MRI environment comprises a patient support portion configured to support the patient, a base portion configured for movement relative to a floor, at least one actuator coupled to the patient support portion and the base portion, the at least one actuator being configured to move the patient support portion relative to the base portion, including but not limited to, changing the elevation of the patient support portion relative to the base portion, and at least one electric motor coupled to the at least one actuator, said actuator causing motion in at least one degree of freedom selected from, but not limited to, a rotary stage, a linear stage, a telescoping stage, a pneumatic stage, a hydraulic stage, a scissor lift, etc. The at least one electric motor may be mounted such that the elevation of the at least one electric motor is fixed relative to the base portion. Furthermore, when the trolley system is positioned adjacent an MRI apparatus within the MRI environment, the magnetic field of the MRI does not interfere with the operation of the at least one electric motor. The trolley may also comprise a plurality of actuators and electric motors.
In another aspect of the present invention, a trolley system configured to transport a patient within an MRI environment comprises a patient support portion configured to support the patient, a base portion configured for movement relative to a floor, and an electric blower coupled to the base portion and fixed to prevent movement of the blower relative to the trolley system, the blower being configured to deliver air to a feature, such as a feature located on the patient transfer device, a feature located on the trolley, an accessory feature, or a feature located on the target modality. When the trolley system is positioned adjacent an MRI apparatus within the MRI environment, the magnetic field of the MRI does not interfere with the operation of the blower.
The trolley system may further comprise a base portion, at least one actuator coupled to the patient support portion and the base portion, and at least one electric motor coupled to the actuator. The at least one actuator may have at least one telescoping stage and be configured to move the patient support portion relative to the base portion and change the elevation of the patient support portion relative to the base portion. The at least one electric motor may be mounted such that the elevation of the at least one electric motor is fixed relative to the base portion, and such that the magnetic field of the MRI does not interfere with operation of the at least one electric motor. The trolley system may also comprise a battery for powering the at least one electric motor and the electric blower. A detachable hose may be used to couple the patient transfer device to the blower.
In yet another aspect of the present invention, a method of delivering a patient to a bore of an MRI device by using a trolley system. The trolley system may include a patient support portion configured to support the patient, a patient transfer device comprising an air bearing on the patient support portion, a base portion configured for movement relative to a floor, an actuator coupled to the patient support portion and the base portion, and one or more electric motors coupled to the actuator, all of the one or more electric motors being mounted such that the elevation of the electric motors is fixed relative to base portion. The method may comprise positioning a trolley system proximate to the bore of the MRI device, such that either end of the trolley system is facing the bore of the MRI device, optionally raising the patient support portion relative to the base portion by actuating the actuator to change the elevation of the patient support portion, providing air to the air bearing, and transferring the patient transfer device from the patient support portion to the target modality, wherein a pull force on the trolley system by a magnetic field of the MRI device is less than or equal to 50 lbs force (and more preferably less than or equal to 25 lbs force) as measured in connection with a nominal 3T MRI device.
In yet another aspect of the present invention, a method of transferring a patient to a target modality within an MRI environment comprises:

    
    
        positioning a trolley system adjacent the target modality within the MRI environment, the trolley system including
        
            a patient support portion configured to support the patient,
            a patient transfer device comprising an air bearing on the patient support portion,
            a base portion configured for movement relative to a floor,
            an actuator coupled to the patient support portion and the base portion, and
            one or more motors coupled to the actuator, all of the one or more motors being mounted such that the elevation of the motors is fixed relative to base portion,
        
        
        optionally raising the patient support portion relative to the base portion by actuating the actuator to change the elevation of the patient support portion;
        providing air to the air bearing; and
        transferring the patient transfer device from the patient support portion to the target modality,
    
    


wherein the magnetic field of the MRI does not interfere with the operation of all of the one or more motors during actuation of the actuator.
According to yet another aspect of the present invention, a method of delivering a patient to a bore of an MRI device comprises positioning a trolley system proximate to the bore of the MRI device, such that an end of the trolley system is facing the bore of the MRI device, actuating the electric blower to deliver air to the patient transfer device, thereby supplying air to the patient transfer device to facilitate movement of the patient, and conveying the patient onto a target modality. The trolley system may be MR Compatible with a maximum magnetic attraction force less than or equal to 50 lbs force and include a patient support portion configured to support the patient, a patient transfer device positioned on the patient support portion, a base portion configured for movement relative to a floor, and an electric blower.
In yet another aspect of the present invention, an imaging system is provided comprising an MRI device, a target modality, a trolley system, and a patient transfer device configured for movement relative to a patient support portion of the trolley system.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top perspective view of a patient trolley and transfer device according to an embodiment of the present invention next to a target modality in an MRI environment;
FIG. 2 is a side view of the patient trolley and transfer device of FIG. 1 within a magnetic field of an MRI machine;
FIG. 3 is a side view of the patient trolley and transfer device of FIG. 1;
FIG. 4 is a schematic side view of the chassis of a patient trolley according to another embodiment of the present invention;
FIG. 5 is a top perspective view of an embodiment of a lift or actuator for a patient trolley according to another embodiment of the present invention; and
FIG. 6 is a schematic top plan view of the relative position of a trolley and an MRI device when determining the pull force on the trolley system.
FIG. 7A is a side view of another embodiment of the trolley system of the present invention, showing the embodiment in a stationary orientation.
FIG. 7B is a side view of the embodiment of FIG. 7A, showing the embodiment in a mobile orientation.
FIG. 7C is a side view of the embodiment of FIG. 7A, showing an angle in which the embodiment in a mobile orientation has a tendency to revert to the stationary orientation.
FIG. 8 is a side view of the embodiment of FIG. 7A within a magnetic field of an MRI machine.
FIG. 9A shows a schematic side view of the embodiment of FIG. 7A, showing certain components of the trolley system.
FIG. 9B shows a schematic side view of the embodiment of FIG. 9A, showing certain components of the trolley system.
FIG. 10 shows the embodiment of FIG. 7A, in use during a lateral transfer situation with a transfer device, the patient support of the target modality, and a separate patient support.
FIG. 11 shows the embodiment of FIG. 7A, in use during a longitudinal transfer situation, with a transfer device and the patient support of the target modality.
FIG. 12 shows a side view the embodiment of FIG. 7A, showing various distance relationships of the at least one wheel, the base portion, and the floor.
FIG. 13 is a diagram illustrating an embodiment of a method of operating the embodiment of the trolley system of FIG. 7A.
FIGS. 14A-14B depict top plan views of the relative position of the embodiment of FIG. 7A and an MRI device when determining the pull force on the trolley system in lateral and longitudinal directions, respectively.



DETAILED DESCRIPTION OF THE INVENTION
The invention is described by reference to exemplary embodiments and variations of those embodiments. Although the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown and described. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the invention.
According to one aspect of this invention, an imaging system is provided comprising an MRI, a target modality, a trolley system, and a patient transfer device configured for movement relative to a patient support portion of the trolley system. The patient transfer device optionally includes an air bearing attached to the underside of the patient transfer device. The imaging system may be combined with a source of low pressure/high volume air coupled to the patient transfer device and configured to deliver air to the air bearing. For example a low pressure/high volume air source may be 0.1 to 5 PSI and 50 to 200 CFM. The air bearing can be of many designs as known to those skilled in the art, including but not limited to, a bladder, a cushion, etc. The trolley system may include at least one actuator, providing at least one degree of motion. The air source provides air flow to the air bearing and facilitates the transfer of the patient from the top surface of the trolley to the patient surface of the target modality.
Also, the trolley system may include an actuator configured to adjust the elevation of a patient support surface relative to a base portion. An actuator may include a lift, a linear stage, a rotary stage, a scissoring mechanism, or any mechanism capable of changing the relative position between two components. The actuator includes, or is coupled to, a motor. When actuated, the motor raises or lowers the elevation of the patient support surface.
Motors for the trolley actuator and blowers used for the operation of the trolley and patient transfer devices may be made of ferromagnetic materials and/or include electrically powered components. The magnetic field can disrupt the operation of the motors, and the ferromagnetic materials can be attracted to the magnetic field of the MRI, thus threatening the safe operation of the trolley and transfer devices. This invention mitigates this risk through placement of the motor and other components to ensure their proper functioning and to reduce magnetic attraction in the MRI environment. As a result, the systems according to the embodiments described herein may be compatible with the MRI environment. As used herein throughout the specification and the claims, the term “MR Compatible” refers to the magnetic attraction force of the trolley system and the operability of one or more electric motors of the trolley system as determined by the MR Compatibility Test Procedure described in the Examples section below.
Regarding the magnetic attraction force of the trolley system, it has been surprisingly discovered that a multi-functional trolley system can be provided according to aspects of this invention while still having a magnetic attraction force that renders the trolley system suitable for use in an MRI environment such as an MRI room. According to embodiments of the invention, the maximum magnetic attraction force is less than or equal to 50 lbs force, and more preferably less than or equal to 25 lbs force, as determined by the MR Compatibility Test Procedure described in the Examples section below.
Regarding the operability of one or more electric motors of the trolley system, it has been surprisingly discovered that a trolley system having one or more electric motors can be provided according to aspects of this invention while still remaining operable in an MRI environment such as an MRI room. According to embodiments of the invention, operability of one or more electric motors of the trolley system is maintained, as determined by the MR Compatibility Test Procedure described in the Examples section below.
Previously, portable blowers have been provided with long hoses for the patient transfer device, so that the blower motor can remain outside of the MRI environment (in practice, outside the MRI room) while the patient is transferred to avoid an unsafe situation. However, it is preferred to avoid the need for such a blower arrangement with long hoses and electrical cords.
By affixing the blower to the trolley according to aspects of this invention, the location and orientation of the blower relative to the MRI machine is controlled such that its function is not impeded. In addition, it has been discovered that the trolley, which is composed primarily of non-magnetic materials, is of sufficient mass that provides an anchoring function for the blower and other features containing ferromagnetic components. This prevents the blower from being dangerously pulled toward and into the MRI machine. Providing a battery power source eliminates the need for electrical cords thereby enabling the unit to be self-contained. Tripping hazards and MRI interference from the electrical cord can also be avoided.
Additionally, it is desirable to optionally use a vacuum pump motor in an MRI environment. Such vacuum pump motors are useful for, among other things, forming vacuum cushions for use during MR imaging. According to aspects of this invention, one or more vacuum pump motors is mounted to the trolley system.
Referring generally to the Figures, the present invention provides a trolley system 14 configured to transport a patient within an MRI environment such as an MRI room, the trolley system 14 comprises a patient support portion configured to support the patient, stowable side rails 21 on either side of the patient support portion, a base portion 15 configured for horizontal movement relative to a floor, at least one lift or pillar 22a, 22b coupled to the patient support portion and the base portion 15, the at least one lift or pillar 22a, 22b being configured to move the patient support portion relative to the base portion 15 and to change the elevation of the patient support portion relative to the base portion 15, and at least one motor 24a, 24b coupled to the at least one lift 22a, 22b. The at least one motor 24a, 24b is mounted such that the elevation of the at least one motor 24a, 24b is fixed, or limited, relative to the base portion 15, and the trolley system 14 is positionable adjacent an MRI apparatus 10 within the MRI environment and the magnetic field of the MRI 10 does not interfere with the operation of the at least one lift 22a, 22b, or at least one blower 19. Alternatively, the motor of the at least one lift 22a, 22b may be mounted to the lower portion of the lift in such a way that the displacement of the motor with respect to the base portion is limited or prevented, such that the motor remains within a weaker portion of the magnetic field.
In another embodiment of the present invention, a trolley system 14 configured to transport a patient within an MRI environment comprises a patient support portion configured to support the patient, a patient transfer device 16 configured for movement relative to the patient support portion, the patient transfer device 16 providing an air bearing, and a blower 19 coupled to the patient transfer device 16 and fixed to prevent movement of the blower 19 relative to the trolley system 14, the blower 19 being configured to deliver air to at least one feature of the trolley system 14 (such as the air bearing). The feature may be selected from the group consisting of a patient transfer device or other accessory features, such as a patient bed, a wound care bed, a bed that provides alternating pressures, a surface designed for therapeutic applications, a surface designed for patient comfort, a skin protection surface, an air powered device, a vacuum cushion, and a compression surface. The feature may also include other accessories known to one skilled in the art. The trolley system 14 is positionably adjacent an MRI apparatus 10 within the MRI environment and the magnetic field of the MRI 10 does not interfere with the operation of the blower 19.
For example, as described in greater detail below, the blower can be configured to deliver air to a target located within an MRI room. The target can be at least one of a patient transfer device, a patient bed, a wound care bed, a bed that provides alternating pressures, a surface designed for therapeutic applications, a surface designed for patient comfort, a skin protection surface, an air powered device, a vacuum cushion and a compression surface.
When the trolley system is a caddy for movement of an electric blower relative to a patient transfer device that is configured for movement relative to a patient support, the electric blower is configured to deliver air to the patient transfer device. In such an example, the patient transfer device can provide an air bearing, and the electric blower is configured to deliver air to the air bearing.
Referring to each of the figures more specifically, wherein like reference numerals used in the figures denote like parts throughout the various figures, a patient trolley 14 according to an embodiment the present invention is illustrated in FIG. 1 within an MRI environment. The patient trolley 14 is adjacent to an MRI table 12 and is located near the bore of an MRI machine 10. The patient trolley 14 includes a patient transfer device 16 to facilitate transfer from the top of the patient trolley 14 to the patient support surface 17 of the MRI table 12. The base portion 15 of the patient trolley 14 includes a connecting hub 20 to provide a connection via a hose 18 to the patient transfer device 16. The connecting hub 20 also provides a portal facilitating connections between the system electronics and the top of the patient trolley 14.
Transfer of a patient from the patient trolley 14 to the MRI table 12 is facilitated by delivering air to an air bearing (not shown) on the underside of the patient transfer device 16 by using the blower 19. This air bearing reduces the friction between the patient transfer device and the surface along which it travels.
The magnetic field strength of most commercial MRI machines used for diagnostic imaging for humans is within the range of 0.35 to 3 Tesla. However, this rating only describes the maximum strength of the magnetic field within the bore of the MRI machine. As illustrated in the schematic illustration of FIG. 2, the magnetic field strength of the MRI machine 10 decreases with distance. The force exerted on any ferromagnetic components is related to the field strength where the components are located. Because portions of the patient trolley will be close to the bore of the MRI machine when the patient trolley is in position to transfer the patient, it is preferred that non-magnetic materials are used to manufacture the patient trolley, particularly the top and leading portions of the patient trolley, which will be in close proximity to the MRI machine.
Due to physical property requirements or cost demands, it may be impractical to include components made solely from non-magnetic materials. In order to further minimize the potential effects of the magnetic field from the MRI machine on the patient trolley, the components, specifically the components having moving parts, are configured, such that the components remain fixed or at least are positioned near the base of the patient trolley. Assuming that the MRI machine has the magnetic field profile of a typical 3T machine (such as the magnetic field profile illustrated in FIG. 2), the base portion 15 of the patient trolley 14 will be exposed to magnetic field strengths generally no greater than 200 mT due to the location of the base portion 15 relative to the MRI machine 10.
Referring now to the embodiment illustrated in FIGS. 3 to 5, the patient trolley 14 includes a top portion having a top surface on which a patient transfer device 16 is located. Stowable side rails 21 are also located along the sides of the top portion. The patient transfer device 16 includes a hose connector 17 to receive one end of a hose 18. The hose 18 preferably has two sections. The top section has two opposing ends in which one end is connected to the hose connecter 17 of the patient transfer device 16 and the opposite end is connected to a top portion of the trolley 14. The bottom section of the hose 18 also has two opposing ends with one end being connected to the top portion of the trolley 14 and the opposite end connected to a blower 19 located in the base portion 15 of the patient trolley 14, and should be of sufficient length to provide enough slack to accommodate the full height range of the trolley top 14. While various blowers can be utilized, one exemplary blower is available from AMETEK Corp. (e.g., AMETEK Lamb Electric 116157-00). The top section of the hose 18 should be of sufficient length to provide enough slack such that the hose 18 remains attached to the patient transfer device 16 when the patient transfer device 16 is transferred from the top surface of the patient trolley 14 to the patient surface of the target modality (e.g., an MRI table). The top section of the hose 18 may also be disconnected when not in use.
Two telescoping pillars 22a, 22b are connected to the underside of the top portion and the base portion 15 of the patient trolley 14. The pillars 22a, 22b are telescoping, so that the elevation of the top surface, and consequently the patient transfer device 16, may be adjusted relative to the base portion 15. For example, according to one exemplary embodiment of the invention, pillars 22a, 22b may include a telescopic pillar such as the TELEMAG TLG system of SKF Group (e.g., model no. TLG 10/11-A, TLG 10/11-B, and TLG 10/11-C or other similar models such as SKF TLG10-CA34F-000). As understood by those of skill in the art, the patient trolleys according various embodiments of the invention may include only one pillar or, alternatively, two or more pillars.
To ensure safe transfer of a patient from the patient trolley to the target modality, the elevation of the top surface of the patient trolley should be about equal to the elevation of the patient surface of the target modality. The base portion 15 may include a plurality of castors or wheels 34a, 34b, so that the trolley system is positionable adjacent the MRI apparatus within the MRI environment. The wheels 34a, 34b are preferably in the form of casters for optimal maneuverability. For example, the wheels 34a, 34b according to one exemplary embodiment include castors provided by Darcor Limited of Toronto, Canada (e.g., model no. T-CLM6-PD). The base portion 15 may include an optional cover 13 that acts as a housing within which various components of the patient trolley 14 are mounted.
Referring to FIG. 4, a schematic representation of the base portion 15 of another embodiment of the present invention is provided. In the embodiment of FIG. 4, the cover 13 has been excluded from the base portion 15 revealing the components within the uncovered base portion 30. Mounted to the base 32 of the uncovered base portion 30 are two actuators 22a, 22b, actuator motors 24a, 24b, blower 19 (and/or vacuum pump), battery pack 26, and control unit 28. The plurality of wheels 34a, 34b may also be attached to the underside of the base portion 15. The battery pack 26 is connected to the actuator motors 24a, 24b, blower 19, and control unit 28, thereby providing sufficient power to operate the system. Types of batteries include, but are not limited to, lithium ion, lead acid, and nickel cadmium, the preferred embodiment being lithium ion.
As explained above, it is preferred that the motors, blower, control unit, and/or battery pack are mounted to the base portion to minimize the effect of the magnetic field of the MRI on the operation of the motors during use of the actuator or the blower during a patient transfer. In one embodiment, the blower may be mounted on the underside of the trolley top as the blower is normally not required to operate while the actuators are moving, which would cause the running motor to be moving through the magnetic field of the MRI, creating additional induced current. The blower can optionally be positioned in a weaker portion of the magnetic field. For example, mounting the blower closer to the distal end of the patient trolley relative to the MRI machine minimizes the potential for interference by the magnetic forces on the blower. More preferably, the components in the base of the patient trolley are mounted, such that the elevation of one or more of these components is fixed relative to the floor upon which the patient trolley travels. Alternatively, the elevational travel of the components can be permitted and limited. For systems in which it is desirable to have the trolley configuration be symmetric from one operator end to the other, it is possible to mount the electronic components near the centerline of the trolley between each end. This minimizes the strength of the magnetic field to which the electronics are subjected when moved into the MRI machine in either orientation.
According to various embodiments of the present invention, it is preferred to include a blower that is firmly attached to the trolley, i.e. not separately portable. A separately portable blower is likely to contain ferromagnetic material and when not firmly attached to the trolley can pose a severe risk of becoming a projectile in an MRI environment.
It is possible for the magnetic forces generated by the MRI machine to overcome the force of gravity or the force holding such a blower in position because the mass of the blower is not sufficient to resist the attraction force generated by the MRI machine. If the blower is not maintained at a safe distance from the MRI machine, the blower may be attracted by and pulled into the bore of the MRI machine. This is a potentially dangerous occurrence because the blower may strike and injure an operator or patient that is also in the vicinity of the MRI machine. It may also damage the MRI machine or the blower itself. Previously, blowers have been placed outside the room in which the MRI is located to mitigate this risk.
Therefore, it is preferable that various embodiments of the patient trolley according to the present invention include a blower that is fixed on the patient trolley, preferably at a position that will remain at a distance from the MRI machine at which the MRI will not interfere with the functioning of the blower motor. Furthermore, it has been discovered that the configuration of the blower's location on the patient trolley according to the various embodiments of the present invention reduces the magnetic attraction force created by the ferromagnetic components of the blower.
Similarly, if the blower for the patient transfer device and the motor or motors used to operate the actuator of the patient trolley include electric motors, the strength of the MRI machine also has the potential to disrupt the operation of the motors. As understood by those of skill in the art, electric motors typically utilize magnetic fields to produce mechanical motion, providing a driving mechanism. These motors can contain both electromagnets and fixed magnets. These electric motors may be disrupted by an external magnetic field. Therefore, the configuration of the motor and blower in the base of the patient trolleys according to various embodiments of the present invention are necessary to ensure proper functioning of the lifting mechanism and delivering air to the patient transfer device.
As explained above, the blower is preferably mounted in the base of the patient trolley sufficiently far away from the bore of the MRI machine, such that the magnetic field of the MRI does not interfere with the operation of the blower. With respect to the pillar motors, some lifting mechanisms include multiple stages with a motor incorporated in each elevating lift of the stage. In such a configuration, the operation of the electric motor may be disrupted by the magnetic field of the MRI machine, if the motor is elevated to a position within a strong field or, forced to operate while moving through a strong magnetic field. For various embodiments of the present invention, it is preferred to use an actuator that is configured, such that the motor remains at or within the base portion of the patient trolley. This may be achieved by using an embodiment of the pillars as illustrated in FIG. 5.
In FIG. 5, pillar 22a is illustrated in an extended position. The pillar 22a is preferably limited to two sections, a bottom section 40 that is mounted to the base of the patient trolley, and a top section 42, which is telescoping and moves relative to the bottom section 40. The motor for the pillar 22a may be mounted within the bottom section 40 of the pillar 22a, such that the elevation of the motor does not change as the top section 42 is raised. As understood by one of skill in the art, the materials used to fabricate the pillar should be selected to accommodate the weight of the top portion of the patient trolley in addition to the weight of a patient transfer device and a patient. The pillar motors should also be selected, such that the motors are able to generate sufficient power to safely raise and lower the patient. If a pillar containing more than two sections is used, it is preferable to employ a mechanism that allows the motor or motors to remain stationary while driving the moving sections.
According to another embodiment of the present invention, a method of transferring a patient to a target modality within an MRI environment is provided. The method comprises first positioning a trolley system adjacent the target modality within the MRI environment. The trolley system comprises a patient trolley having a patient support surface and a base portion. Positioning includes ensuring that the patient support surface is about parallel and adjacent to the patient support surface of the target modality. Next, a user may optionally raise the patient support portion relative to the base portion by actuating a lift to change the elevation of the patient support portion relative to the base portion. This may be optional because in certain circumstances the height of the patient support portion may be approximately equal to the height of the target modality, therefore adjustment is not necessary in such circumstances. In fact, a fixed height trolley (without motor and actuator) may be provided according to aspects of this invention. Alternatively, the height of the target modality may be adjusted to be approximately equal to the height of the patient support portion. If the trolley system also includes a patient transfer device on the patient support surface, the method further comprises providing air to the air bearing of the patient transfer device and transferring the patient transfer device from the patient support portion to the target modality.
EXAMPLES
Advantageous properties of aspects of this invention can be observed by reference to the following examples, which illustrate but do not limit the invention.
MR Compatibility Test Procedure
The following MR Compatibility Test Procedure is used to determine MR Compatibility according to aspects of this invention. It is used to determine the magnetic attraction force of a trolley system as well as the operability of one or more electric motors included in the trolley system. Reference is made to FIG. 6, which illustrates schematically the relative position of a trolley system and an MRI device.
I. Test Setup
Place the trolley system on a hard flat surface (such as a linoleum floor), ensuring that brakes of the trolley system are in their unlocked position.
II. Procedure
A. Testing Equipment

    
    
        The MRI device used is a Siemens MAGNETOM Verio 3T MRI scanner device or equivalent nominal 3T MRI scanner with a horizontal Bo orientation. Other equivalent nominal 3T MR scanners are available from Siemens, GE, Philips, Toshiba and others.
    
    


B. Trolley Orientation—Gantry End Against Bore

    
    
        Lower the trolley system to its lowest position. Orient the trolley such that the gantry end is facing the bore of the magnet and the trolley is parallel to the MRI table. Slowly introduce the trolley into the magnetic field until the gantry end is against the face of the bore, or the gantry end is as close as possible to the magnet.
    
    


C. Force Measurement

    
    
        Using a force gauge, ensure there is no load on the gauge and verify the dial is zeroed. To zero the gauge, rotate the dial face so that the gauge needle rests above the zero mark.
        At the locations described in FIG. 6, use the force gauge to pull the trolley horizontally away from the bore of the magnet until the trolley begins to move and record the Lateral Force Measurement and the Longitudinal Force Measurement.
        Repeat these measurements with the trolley in its highest pillar position.
    
    


D. Electronic Functionality Test

    
    
        While the trolley is against the face of the bore in the position shown in FIG. 6, verify that each of the following electronic systems function, if present in the tested trolley.
        1. Pillar Travel
        
            For a trolley system having height adjustment with one or more electric motors, test the operation of those motors. For example, using ‘up’ and ‘down’ arrows on a control panel of one embodiment of the trolley system, move the pillars from their lowest position to their highest position. For embodiments with plural pillars, the pillars should reach their full extent of travel synchronized with each other.
        
        
        2. Blower Activation
        
            For a trolley system having one or more blowers with electric motors, test the operation of those motors. Put the brakes in their locked position. Actuate the blower(s). Actuating any of the blowers should cause the blower to turn on and air to travel down the hose.
        
        
        3. Vacuum Activation
        
            For a trolley system having one or more vacuum pumps with electric motors, test the operation of those motors. Put the brakes in their locked position. Actuate the vacuum pump(s). Actuating any of the vacuum pumps should cause the actuated vacuum pump to turn on and produce vacuum.
        
        
    
    


E. Trolley Orientation—Operator End Against Bore

    
    
        Lower the trolley to its lowest position. Orient the trolley such that the operator end is facing the bore of the magnet and the trolley is parallel to the MRI table. Slowly introduce the trolley into the magnetic field until the operator end is against the face of the bore, or the operator end is a close as possible to the magnet.
        Repeat the Force Measurement and Electronic Functionality Test above.
    
    


Example 1
In order to determine the magnetic attraction force of a trolley system made according to an embodiment of the present invention, a trolley similar to the embodiment illustrated in FIG. 3 was tested proximate to a Siemens MAGNETOM Verio 3T MRI device. A Siemens MAGNETOM Espree 1.5T MRI device was also used for comparison purposes. The trolley included stowable rails 21, lifts 22a, 22b, as well as a memory system in order to store multiple pre-selected positions for the lifts 22a, 22b. The operator end of the trolley is the right-side end of the trolley in the view provided in FIG. 3, where the hose 18 is located, and the gantry end is the left-side end. The trolley 14 was introduced into the magnetic field until the gantry end was against the face of the bore. At the locations illustrated in FIG. 6, the brakes on the trolley were disengaged and a force gauge was used to pull the trolley 14 away from the bore of the magnet until the trolley 14 began to move and the maximum force was recorded. This procedure was repeated after extending the lifts 22a, 22b to raise the trolley 14 to its highest elevation and deploying the side rails 21 to the raised position. The procedure was repeated again with the trolley 14 in the raised and lowered positions after turning the trolley 14 180 degrees, such that the operator end of the trolley 14 was against the bore of the MRI.
The results of the force measurement testing are provided in the following table:


















Force



MRI
Trolley
Pull
Measurement



(T)
Configuration
Direction
(lbs force)



















Gantry
1.5
Lowered
Lateral
7


End
1.5
Lowered
Longitudinal
6


Against
1.5
Raised
Lateral
5


Bore
1.5
Raised
Longitudinal
10



3
Lowered
Lateral
10



3
Lowered
Longitudinal
10



3
Raised
Lateral
9.5



3
Raised
Longitudinal
12


Operator
1.5
Lowered
Lateral
5.5


End
1.5
Lowered
Longitudinal
5


Against
1.5
Raised
Lateral
7


Bore
1.5
Raised
Longitudinal
7



3
Lowered
Lateral
8



3
Lowered
Longitudinal
11



3
Raised
Lateral
10



3
Raised
Longitudinal
11









In each of the four orientations described above, the function of the electronic systems was tested in proximity of the 1.5T and 3T MRI. The electromechanical functions of the following user-interfacing components were tested: the blower, the vertical operation of the pillar, the memory control of the pillar height, a pillar calibration module, the control panel, an alarm, a main power switch, and a safety interlock. In a first test, the pillars 22a, 22b were lowered and raised from their lowest to highest positions. In a second test, four separate memory positions for the pillars 22a, 22b were selected to determine if the trolley was able to correctly alternate between the various height settings. In a third test, an automatic calibration mode of the pillars 22a, 22b was performed. In a fourth test, the blower was operated while the brakes on the trolley wheels were engaged to test the functioning of a safety interlock. In a fifth test, the blower was operated while the brakes were disengaged to test the functioning of an alarm. In a sixth test, a control panel stop function was tested to determine whether the control panel and blower buttons would remain unresponsive. In a seventh test, the main power switch was toggled to determine whether the electronic system was able to start up normally. All of the electronic functions of the trolley 14 operated correctly and exhibited no interference while in proximity of either MRI magnet.
According to one aspect of the invention, a trolley system is configured to transport a patient within an MRI room, the trolley system comprising: a patient support portion configured to support the patient; a base portion configured for movement relative to a floor; at least one actuator coupled to the patient support portion and the base portion, the at least one actuator being configured to move the patient support portion relative to the base portion and to change the elevation of the patient support portion relative to the base portion; and at least one electric motor coupled to the at least one actuator, wherein the at least one electric motor is mounted such that the elevation of the at least one electric motor is fixed relative to the base portion; wherein the trolley system is MR Compatible with a maximum magnetic attraction force less than or equal to 50 lbs force.
According to another aspect of the invention, a trolley system is configured to transport a patient within an MRI room, the trolley system comprising: a patient support portion configured to support the patient; a base portion configured for movement relative to a floor; and an electric blower coupled to the base portion of the trolley system and fixed to prevent movement of the electric blower relative to the trolley system, the electric blower being configured to deliver air to a feature of the trolley system; wherein the trolley system is MR Compatible with a maximum magnetic attraction force less than or equal to 50 lbs force.
According to another aspect of the invention, a method of delivering a patient to a bore of an MRI device is provided, the method comprising: positioning a trolley system proximate to the bore of the MRI device, such that an end of the trolley system is facing the bore of the MRI device, the trolley system being MR Compatible with a maximum magnetic attraction force less than or equal to 50 lbs force and including a patient support portion configured to support the patient, a base portion configured for movement relative to a floor, an actuator coupled to the patient support portion and the base portion, and one or more electric motors coupled to the actuator; optionally raising the patient support portion relative to the base portion by actuating the actuator to change the elevation of the patient support portion relative to the base portion; and conveying the patient onto a target modality.
According to another aspect of the invention, an imaging system is provided comprising: an MRI device; and a trolley system according to aspects of this invention.
According to another aspect of the invention, a trolley system is configured to transport a patient within an MRI environment, the trolley system comprising: a patient support portion configured to support the patient; a base portion configured for movement relative to a floor; at least one actuator coupled to the patient support portion and the base portion, the at least one actuator being configured to move the patient support portion relative to the base portion and to change the elevation of the patient support portion relative to the base portion; and at least one electric motor coupled to the at least one actuator; wherein the at least one electric motor is mounted such that the elevation of the at least one electric motor is fixed relative to the base portion; and wherein the trolley system is positionable adjacent an MRI apparatus within the MRI environment and the magnetic field of the MRI does not interfere with the operation of the at least one electric motor.
According to another aspect of the invention, a trolley system is configured to transport a patient within an MRI environment, the trolley comprising: a patient support portion configured to support the patient; an electric blower coupled to a feature of the trolley system and fixed to prevent movement of the electric blower relative to the trolley system, the electric blower being configured to deliver air to the patient transfer device; wherein the trolley system is positionable adjacent an MRI apparatus within the MRI environment and the magnetic field of the MRI does not interfere with the operation of the electric blower.
According to another aspect of the invention, a method of transferring a patient to a target modality within an MRI environment is provided, the method comprising: positioning a trolley system adjacent the target modality within the MRI environment, the trolley system including a patient support portion configured to support the patient, a patient transfer device comprising an air bearing on the patient support portion, a base portion configured for movement relative to a floor, an actuator coupled to the patient support portion and the base portion, and one or more electric motors coupled to the actuator, all of the one or more electric motors being mounted such that the elevation of the electric motors is fixed relative to base portion; optionally raising the patient support portion relative to the base portion by actuating the actuator to change the elevation of the patient support portion relative to the base portion; delivering air to the air bearing; and transferring the patient transfer device from the patient support portion of the trolley to the target modality; wherein the magnetic field of the MRI does not interfere with the operation of all of the one or more electric motors during actuation of the actuator.
According to another aspect of the invention, a method of delivering a patient to a bore of an MRI device is provided, the method comprising positioning a trolley system proximate to the bore of the MRI device, such that an end of the trolley system is facing the bore of the MRI device, the trolley system being MR Compatible with a maximum magnetic attraction force less than or equal to 50 lbs force and including a patient support portion configured to support the patient, a patient transfer device positioned on the patient support portion, a base portion configured for movement relative to a floor, and an electric blower, actuating the electric blower to deliver air to the patient transfer device, thereby supplying air to the patient transfer device to facilitate movement of the patient; and conveying the patient onto a target modality.
In an alternate embodiment of the present invention and referring generally to FIGS. 10-11, a trolley system 50 is configured to move air within an MRI room and adjacent an MRI apparatus 52 in the MRI room. The trolley system 50 comprises a base portion 54, which includes at least one wheel 56 that is positioned to selectively permit movement of the trolley system 50 relative to a floor 58. Further, the base portion 54 is movable between a mobile orientation (as shown in FIG. 7B) and a stationary orientation (as shown in FIG. 7A). In the mobile orientation, the at least one wheel 56 of the base portion 54 facilitates movement of the trolley system 50 relative to the floor 58. In the stationary orientation, the at least one wheel 56 of the base portion 54 is prevented from facilitating the movement of the trolley system 50 relative to the floor 58.
The trolley system 50 further includes an electric blower 60 coupled to the base portion 54. The electric blower 60 is fixed and is configured as being prevented from movement relative to the base portion 54. When the base portion 54 is in the stationary position, the electric blower 60 is configured to move air. Notably, when the electric blower 60 moves air, the position of the blower 60 relative to the MRI apparatus 52 in the MRI room does not change. Conventionally, such electric blowers are configured to convey air from one side of the blower to another. In this way, such blowers can be configured such that they can either deliver or withdraw air, for example, connecting an air delivery means to either the inlet or the outlet. As such, it would be understood by someone skilled in the art that a blower can act in both the mode of providing pressure and/or vacuum to a target device. In addition, it would be understood that electric blowers of this type can include one or more of the following: centrifugal blowers, piston blowers, rotary vane vacuum pumps, diaphragm, liquid rings, venturi systems, screw pumps, and other blower means known to a person having ordinary skill in the art. Depending on the application, one might incorporate multiple blowers or multiple types of blowers or one might connect to multiple sides of a single blower to selectively configure the system to either deliver or withdraw air, for instance utilizing a valve or switch or other means known to a person having ordinary skill in the art.
As illustrated in the schematic illustration of FIG. 8, a magnetic field strength of the MRI apparatus 52 decreases with distance. To minimize the potential effects of the magnetic field generated by the MRI apparatus 52, the electric blower 60 remains in a fixed position relative to the MRI apparatus 52 and is at least positioned near the base of the MRI apparatus 52. In particular, the electric blower 60 is positioned such that the electric blower 60 remains within a relatively weaker portion of the magnetic field generated by the MRI apparatus 52 (such as the magnetic field profile illustrated in FIG. 8) in the MRI room, thereby reducing the effect of the magnetic field on the operation of the electric blower 60 during use of the electric blower 60. This way, the trolley system 50 is positionable adjacent to the MRI apparatus 52 within the MRI room and the magnetic field of the MRI apparatus 52 does not interfere with the operation of the electric blower 60 in such a position. In other words, the electric blower 60 is functional and configured to operate while adjacent the MRI apparatus 52 and while the magnetic field is generated by the MRI apparatus 52. Specifically, the trolley system 50 is configured to be MR Compatible with a maximum magnetic attraction force less than or equal to 50 lbs force.
As a non-limiting example, the trolley system is a caddy 50a. The caddy 50a is operable to move the electric blower 60 relative to a patient transfer device 64 (FIG. 10). The patient transfer device 64 has an air bearing (not shown), which may be attached to the underside of the patient transfer device 64 and the air bearing can be coupled to the electric blower 60 configured to move air, such as deliver or withdraw air, for facilitating patient transfers. The patient transfers may involve movement of the patient transfer device 64 relative to a patient support 66 and operation of the electric blower 60 to move air to or from the patient transfer device 64. Although the electric blower 60 is illustrated to move air to or from the patient transfer device 64, as illustrated in FIGS. 10-11, it should be understood that the electric blower 60 can be configured to move air to or from at least one of the patient transfer device 64, a patient bed, a wound care bed, a bed that provides alternating pressures, a surface designed for therapeutic applications, a surface designed for patient comfort, a skin protection surface, an air powered device, a vacuum cushion, and a compression surface.
Referring now to FIGS. 7A-7C and 9A-9B, the caddy 50a comprises the base portion 54, to which is coupled the electric blower 60 configured to move air, such as deliver or withdraw air. As seen in FIG. 9B, the base portion 54 includes a battery 68 configured to power the electric blower 60 and a bottom surface 70 comprising a floor-contacting surface 70a. Furthermore, a magnetic field indicator 86 (FIG. 9B) may be mounted to the base portion 54 to indicate when the magnetic field sensed by the magnetic field indicator 86 is above a threshold magnetic field strength. The magnetic field indicator 86 (FIG. 9B) may provide feedback, such as visual feedback (e.g. an LCD display screen, LED indicators), audio feedback (e.g., a speaker, a buzzer), or tactile feedback (e.g., haptic actuators), or any other means for providing feedback known to a person of ordinary skill in the art. Although FIG. 9B shows the magnetic field indicator 86 as being mounted to the base portion 54, it may also be mounted to a handle 72 (discussed further below). The magnetic field indicator 86 may be incorporated for additional user and safety considerations in the event that the trolley system 50 is used in magnetic fields of unknown field strengths or to provide additional or redundant levels of safety.
In addition, the base portion 54 includes an inlet 74, such as a hose inlet, for receiving an end portion of a flexible hose or tube 76 (FIGS. 10-11). Correspondingly, the opposite end portion of the flexible hose or tube 76 is in communication with a portion of the patient transfer device 64 (FIG. 10-11) or the air bearing (not shown) attached to the underside of the patient transfer device 64, thereby forming an air passageway between the electric blower 60 and the patient transfer device 64 or the air bearing (not shown). In other words, the electric blower 60 moves air to or from the patient transfer device 64 via the flexible hose or tube 76.
As seen in FIG. 9B, the blower 60 is in a fixed position within the caddy 50a, such that the electric blower 60 is prevented from movement relative to the caddy 50a. Preferably, the blower 60 is positioned in a central or lower region of the base portion 54. Additionally or optionally, the battery 68 is positioned in the central region of the base portion 54. Further, the blower 60 is also in a fixed position relative to the MRI apparatus 52 when the blower 60 is operational and moves air.
As illustrated in FIGS. 8 and 9B, the electric blower 60 is positioned within the caddy 50a, such that the blower 60 remains within a relatively weaker portion of the magnetic field generated by the MRI apparatus 52. As an advantage of this, the electric blower 60 will operate when the caddy 50a is adjacent to the MRI apparatus 52 and while the MRI apparatus 52 generates the magnetic field.
This advantageous positioning reduces the effects of the magnetic field (such as the magnetic field profile illustrated in FIG. 8) on the operation of the electric blower 60. This can be partially demonstrated by the magnetic force of attraction on the caddy 50a. In a preferred embodiment, the magnetic force of attraction on the caddy 50a is less than 50 pounds of force. In a further preferred embodiment, the magnetic force of attraction on the caddy 50a is less than 25 pounds of force. This is measured using the MR Compatibility Test Procedure: Caddy Embodiment, as described further below.
As illustrated in FIG. 7A, the base portion 54 may include a non-magnetic supplemental mass 78 mounted to the base portion 54 to increase the mass of the trolley system 50 to a threshold mass. It should be understood, however, that the threshold mass may be reached without the use of the non-magnetic supplemental mass 78, such that the caddy 50a and the components therein have sufficient total mass to reach the threshold mass.
Still further, the base portion 54 additionally has the at least one wheel 56 positioned to selectively permit movement of the caddy 50a relative to the floor 58. Preferably, the at least one wheel 56 includes two wheels. The base portion 54 of the caddy 50a is movable between two orientations, the mobile orientation (FIGS. 7B, 9B) and the stationary orientation (FIGS. 7A, 9A), via the at least one wheel 56. In the stationary orientation, the at least one floor-contacting surface 70a of the base portion 54 is adjacent or makes contact with the floor 58. In the mobile orientation, the at least one floor-contacting surface 70a of the base portion 54 is spaced or raised a distance or height, h, away from the floor 58 and a portion of the at least one wheel 56 is in contact with the floor 58 (FIG. 7B). Accordingly, the at least one wheel 56 facilitates movement of the caddy 50a across the floor 58 in any direction, when the caddy 50a is in the mobile orientation.
In the stationary orientation, the at least one wheel 56 is prevented from facilitating movement of the caddy 50a across the floor 58. This may be accomplished in a variety of ways known to a person having ordinary skill in the art, such as powered or manual brakes, wheel locks, and other mechanical or electrical means for inhibiting motion. Preferably, the prevention of movement of the at least one wheel 56 is accomplished by positioning the at least one wheel 56 such that it contacts the floor 58 when the caddy 50a is in the mobile orientation, but the at least one wheel 56 does not contact the floor 58 when the caddy 50a is in the stationary orientation. Stated differently, the at least one wheel 56 is elevated at a distance d (as seen in FIG. 12) relative to the floor 58, and thus the at least one wheel 56 is prevented from facilitating movement of the caddy 50a relative to the floor 58 in the stationary orientation.
In a further preferred embodiment, as shown in FIG. 12, the at least one wheel 56 is mounted to the base portion 54, such that it is possible to select between the mobile and stationary orientations by changing the angle or tilting the caddy 50a about an axis which is positioned substantially in alignment with the center, c, or axel of the at least one wheel 56. The at least one wheel 56 is further mounted to the base portion 54, such that the radius of the wheel, r, is smaller than a distance D from c to the floor contacting surface 70a of the base portion 54. This creates a smaller distance d between the bottom of the at least one wheel 56 and the floor 58, which spaces or raises the at least one wheel 56 from the floor 58 in the stationary orientation.
In a further preferred embodiment, as seen in FIGS. 7A-7B, a center of mass 80 of the trolley system 50 is positioned relatively forward relative to the axis toward a front of the trolley system 50 in the stationary orientation. In an example, the center of mass 80 of the caddy 50a is located forward of the axel of the at least one wheel 56 in the stationary orientation, between a front face 82 of the caddy 50a and the axel of the at least one wheel 56.
In the mobile orientation, the center of mass 80 of the trolley system 50 is positioned relatively over the axis in the mobile orientation. In an example, the center of mass 80 of the caddy 50a is located relatively above and closer to the center c of the at least one wheel 56, creating an ergonomic advantage for moving or transporting the caddy 50a. The handle 72 is configured to be mounted to the base portion 54 and the handle 72 can be manipulated to shift the caddy 50a into the mobile orientation and shift the center of mass 80 relatively above or over center c of the at least one wheel 56, thereby allowing the caddy 50a to be easily guided for movement relative to the floor 58.
In a further preferred embodiment, as illustrated in FIG. 7C, when the center of mass 80 of the trolley system 50 is positioned between the axis and the front of the trolley system 50, the trolley system 50 will tend to move from the mobile orientation to the stationary orientation when released from the mobile orientation. In an example, the center of mass 80 of the base portion 54 of the caddy 50a is positioned such that if the handle 72 of the caddy 50a is released within the range of angles between the stationary position and the mobile orientation, the caddy 50a will tend to revert to the stationary orientation.
Referring now to FIG. 13, a method 100 of moving a patient relative to a bore of an MRI device using a patient transfer device is provided. The method 100 includes steps of positioning a trolley system proximate to the bore of the MRI device, moving the trolley system from a mobile orientation to a stationary orientation, actuating an electric blower to move air, such as deliver or withdraw air, to the patient transfer device, moving a patient and the patient transfer device relative to the bore of the MRI device. Additional details of method 100 are set forth below with respect to the features of trolley system 50.
In step 102, a trolley system is positioned proximate to the bore of an MRI device. In an example, a trolley system 50 is positioned proximate to the bore of the MRI device 52 and the trolley system 50 is MR Compatible with a maximum magnetic attraction force less than or equal to 50 lbs force. The trolley system 50 further comprises a base portion 54 configured for movement relative to a floor 58. The trolley system 50 also includes at least one wheel 56 coupled to the base portion 54 and positioned for movement of the base portion 54 relative to the floor 58. In addition, an electric blower 60 is mounted to the base portion 54, such as in a central or lower region of the base portion 54. The blower 60 is positioned in such a way that the electric blower 60 remains within a relatively weaker portion of a magnetic field generated by the bore of the MRI device 52 (such as the magnetic field profile illustrated in FIG. 8), thereby reducing the effect of the magnetic field on the operation of the electric blower 60 during use of the electric blower 60. Further, an optional step 102 includes positioning the at least one wheel 56 to contact the floor 58 to permit the movement of the trolley system 50 relative to the floor 58 in a mobile orientation.
In step 104, a trolley system is moved from a mobile orientation to a stationary orientation. In an example, the trolley system 50 having the base portion 54 is moved from the mobile orientation, in which the at least one wheel 56 facilitates the movement of the trolley system 50 relative to the floor 58, to the stationary orientation, in which the at least one wheel 56 is prevented from facilitating the movement of the trolley system 50 relative to the floor 58. Further, an optional step 104 includes spacing or raising the at least one wheel 56 from the floor 58 for the distance, d, to prevent the at least one wheel 56 from facilitating the movement of the trolley system 50 relative to the floor 58 in the stationary orientation.
In step 106, an electric blower is actuated to deliver air to a patient transfer device. In an example, the electric blower 60 is actuated to move air, such as deliver or withdraw air, to the patient transfer device 64 to facilitate movement of a patient 84. The electric blower 60 remains in operation while adjacent to the bore of the MRI device 52 and while the magnetic field is being generated by the bore of the MRI device 52 (such as the magnetic field profile illustrated in FIG. 8).
In step 108, the patient transfer device is moved relative to the bore of the MRI device.
Method 100 may further include the trolley system 50 being configured for use with a patient support portion 66 configured to support the patient 84. Method 100 may further comprise moving the patient 84 and the patient transfer device 64 relative to the patient support portion 66.
Examples Relating to Caddy Embodiment
MR Compatibility Test Procedure: Caddy Embodiment
The caddy was introduced into the MRI environment. The MRI scanner used in the below test was a Siemens MAGNETOM Prisma 3T MRI scanner. The caddy was placed adjacent to the scanner table, facing the bore. The caddy was moved towards the bore until a magnetic field detector indicated that the caddy had crossed the 30 Gauss field strength boundary. The caddy was returned to the stationary orientation and moved backwards until the alarm stopped. The distance from the front of the caddy to the face of the bore was measured, and the axel position was marked with tape. A force measurement to move along the floor was taken by balancing the caddy on its wheels and pulling on a strap attached to the hose inlet until the caddy begins to roll (the longitudinal position). The longitudinal position is illustrated in FIG. 14B. The caddy was then rotated 90 degrees, such that it faces the MRI table. The caddy was centered on the tape used to initially mark the axel. The force to move measurement was taken again in this position (the lateral position). The lateral position is illustrated in FIG. 14A. This procedure was repeated for the 100 Gauss field strength boundary, the force of noticeable attraction location, half distance from noticeable attraction location, and against the bore of the MRI apparatus. The function of the electrical blower incorporated in the caddy was also assessed at each of these locations. The results are summarized in the table below.














Device Location
Test 





(Distance from
Orientation
Force




face of
(relative to
(lbs
Force
Blower


MRI Bore)
MR table)
force)
(N)
Functional?



















Baseline (outside
N/a
2
8.9
Yes


MRI room)






30 Gauss Alarm
Longitudinal
1.5
6.7
Yes


Point (86 in)
Lateral
2
8.9
Yes


100 Gauss Alarm
Longitudinal
2
8.9
Yes


Point (53 in)
Lateral
2
8.9
Yes


Point of Noticeable
Longitudinal
2
8.9
Yes


Attraction (24 in)
Lateral
2
8.9
Yes


Half distance
Longitudinal
5
22.2
Yes


from Noticeable
Lateral
3.5
15.6
Yes


Attraction (12 in)






Against Face of
Longitudinal
22.5
100.1
Yes


MRI Bore
Lateral
8.5
37.8
Yes









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.

## Claims

1. A trolley system operable within an MRI room and adjacent an MRI apparatus in the MRI room, the trolley system comprising:
a base portion having at least one wheel positioned to selectively permit movement of the trolley system relative to a floor, the base portion being movable between a mobile orientation in which the at least one wheel facilitates the movement of the trolley system relative to the floor and a stationary orientation in which the at least one wheel is prevented from facilitating the movement of the trolley system relative to the floor, wherein the at least one wheel is mounted to rotate about an axis that is fixed in position relative to the base portion of the trolley system and further wherein a distance from the axis to the at least one floor-contacting surface of the base portion is greater than a distance from the axis to a floor-contacting surface of the at least one wheel; and
an electric blower coupled to the base portion of the trolley system and fixed to prevent movement of the electric blower relative to the trolley system, the electric blower being configured to move air when the base portion is in the stationary orientation, and the relative position of the blower to the MRI apparatus in the MRI room does not change when the blower moves air and when the base portion is in the stationary orientation, the electric blower being mounted such that the electric blower remains within a weaker portion of a magnetic field generated by the MRI apparatus in the MRI room, thereby reducing the effect of the magnetic field on the operation of the electric blower during use of the electric blower;
wherein the trolley system is MR Compatible with a maximum magnetic attraction force less than or equal to 50 lbs force; and
wherein the trolley system is positionable adjacent the MRI apparatus within the MRI room and the magnetic field of the MRI apparatus does not interfere with the operation of the electric blower when the trolley system is positioned adjacent the MRI apparatus, such that the electric blower operates while adjacent the MRI apparatus and while the magnetic field is generated by the MRI apparatus.

2. A trolley system operable within an MRI room and adjacent an MRI apparatus in the MRI room, the trolley system comprising:
a base portion having at least one wheel positioned to selectively permit movement of the trolley system relative to a floor, the base portion being movable between a mobile orientation in which the at least one wheel facilitates the movement of the trolley system relative to the floor and a stationary orientation in which the at least one wheel is prevented from facilitating the movement of the trolley system relative to the floor, wherein the at least one wheel is mounted to rotate about an axis that is fixed in position relative to the base portion of the trolley system and further wherein the center of mass of the trolley system is positioned relatively forward relative to the axis toward a front of the trolley system in the stationary orientation, and wherein the venter of mass is positioned relatively over the axis in the mobile orientation; and
an electric blower coupled to the base portion of the trolley system and fixed to prevent movement of the electric blower relative to the trolley system, the electric blower being configured to move air when the base portion is in the stationary orientation, and the relative position of the blower to the MRI apparatus in the MRI room does not change when the blower moves air and when the base portion is in the stationary orientation, the electric blower being mounted such that the electric blower remains within a weaker portion of the magnetic field generated by the MRI apparatus in the MRI room, thereby reducing the effect of the magnetic field on the operation of the electric blower during use of the electric blower;
wherein the trolley system is MR Compatible with the maximum magnetic attraction force less than or equal to 50 lbs force; and
wherein the trolley system is positionable adjacent the MRI apparatus within the MRI room and the magnetic field of the MRI apparatus does not interfere with the operation of the electric blower when the trolley system is positioned adjacent the MRI apparatus, such that the electric blower operates while adjacent the MRI apparatus and while the magnetic field is generated by the MRI apparatus, wherein the center of mass of the trolley system is positioned between the axis and the front of the trolley system such that the trolley system moves from the mobile orientation to the stationary orientation when released from the mobile orientation.

3. A method of moving a patient relative to a bore of an MRI device using a patient transfer device, the method comprising:
positioning a trolley system proximate to the bore of the MRI device, the trolley system being MR Compatible with a maximum magnetic attraction force less than or equal to 50 lbs force and including
a base portion configured for movement relative to a floor,

at least one wheel coupled to the base portion and positioned for movement of the base portion relative to the floor, and
an electric blower, the electric blower being mounted such that the electric blower remains within a weaker portion of a magnetic field generated by the bore of the MRI device, thereby reducing the effect of the magnetic field on the operation of the electric blower during use of the electric blower;
moving the base portion from a mobile orientation in which the at least one wheel facilitates the movement of the trolley system relative to the floor to a stationary orientation in which the at least one wheel is prevented from facilitating the movement of the trolley system relative to the floor, the at least one wheel being mounted to rotate about an axis that is fixed in position relative to the base portion of the trolley system and a distance from the axis to the at least one floor-contacting surface of the base portion being greater than a distance from the axis to a floor-contacting surface of the at least one wheel;
actuating the electric blower to move air to the patient transfer device, thereby moving air to or from the patient transfer device to facilitate movement of the patient, the electric blower operating while adjacent the bore of the MRI device and while the magnetic field is being generated by the bore of the MRI device; and
moving the patient and the patient transfer device relative to the bore of the MRI device.

4. The trolley system of claim 1, the trolley system being a caddy for movement of the electric blower relative to a patient transfer device that is configured for movement relative to a patient support, the electric blower being configured to move air to the patient transfer device.

5. The trolley system of claim 4, the patient transfer device providing an air bearing, and the electric blower being configured to move air to the air bearing.

6. The trolley system of claim 1, further comprising at least two wheels positioned for movement of the trolley system relative to the floor.

7. The trolley system of claim 1, wherein the trolley system is MR Compatible with a maximum magnetic attraction force less than or equal to 25 lbs force.

8. The trolley system of claim 1, further comprising a battery for powering the electric blower.

9. The trolley system of claim 8, wherein at least one of the battery and the electric blower is located within a central region of the base portion.

10. The trolley system of claim 1, the at least one wheel being positioned to contact the floor to permit movement of the trolley system relative to the floor when the base portion is in the mobile orientation, and the at least one wheel being spaced from the floor to be prevented from facilitating the movement of the trolley system relative to the floor when the base portion is positioned in the stationary orientation.

11. The trolley system of claim 1, wherein the at least one wheel can be locked to retain the trolley system in the stationary orientation and unlocked to revert to the mobile orientation.

12. The trolley system of claim 1, the base portion having a bottom surface comprising at least one floor-contacting surface positioned to elevate the at least one wheel from the floor when the base portion is in the stationary orientation.

13. The trolley system of claim 1, wherein the center of mass of the trolley system is positioned relatively forward relative to the axis toward a front of the trolley system in the stationary orientation, and wherein the center of mass is positioned relatively over the axis in the mobile orientation.

14. The trolley system of claim 1, wherein air is movable by the electric blower to or from at least one of a patient transfer device, a patient bed, a wound care bed, a bed that provides alternating pressures, a surface designed for therapeutic applications, a surface designed for patient comfort, a skin protection surface, an air powered device, a vacuum cushion and a compression surface.

15. The trolley system of claim 1, wherein the electric blower of the trolley system is configured to be coupled to a patient transfer device for moving air to an air bearing of the patient transfer device.

16. The trolley system of claim 1, further comprising nonferromagnetic supplemental mass mounted to the base portion to increase the mass of the trolley system to a threshold mass.

17. The trolley system of claim 1, further comprising a handle mounted to the base portion to facilitate movement of the trolley system.

18. The method of claim 3, the trolley system being configured for use with a patient support portion configured to support the patient, the method further comprising moving the patient and the patient transfer device relative to the patient support portion.

19. The trolley system of claim 1, wherein the electric blower is configured to deliver air to a target located within the MRI room.