Patent Description:
Radiation therapy and diagnostic imaging equipment are used frequently in hospitals and treatment centers. Modern techniques for radiation therapy and diagnostic imaging typically require that patients be positioned and immobilized in a precise orientation to ensure accurate imaging and treatment. In particular, treatment of a tumor by radiation therapy is generally preceded by a diagnostic imaging procedure referred to as simulation. During simulation, the patient is positioned in the manner anticipated for treatment. The manner anticipated for treatment includes the physical orientation of the patient using the positioning and immobilization devices that will be used during the treatment.

Once the physical orientation of the patient for treatment has been determined, the diagnostic imaging procedure can be used to collect a computer data set of the patient (DICOM) which contains an accurate representation of the location of the tumor to be treated. The DICOM can be imported into treatment planning software (TPS) such that the treatment can be modeled and planned.

To ensure accurate tumor location identification for treatment, it is critical in such applications that the patient be situated in the same position and orientation on the same devices or supports during treatment of the patient. The patient positioning and immobilization process in preparation for use of the treatment or imaging equipment can be extensive and time consuming. Therefore, to better utilize the time on the treatment or imaging equipment, it can generally be beneficial to position and immobilize the patient on a device or support other than the treatment or imaging equipment. In some cases, the diagnostic imaging during simulation and the subsequent treatment are performed on the same day. In these cases, it can be beneficial to position and immobilize the patient on the device or support once and keep the patient immobilized throughout the two procedures.

Thus, a need exists for patient transfer devices which define substantially homogenous structures and provide safe transport of patients during the wide variety of medical procedures conducted. Examples of these procedures include radiation therapy, brachytherapy, operating room procedures, emergency medical services, etc. These and other needs are addressed by the patient transfer devices and associated systems and methods of the present invention.

<CIT> illustrates for example an air pallet type patient mover, formed principally by top, intermediate and bottom thin flexible sheets sealed together about their edges and defining a plenum chamber between the intermediate and bottom sheets and a backing member cavity between the top sheet and the intermediate sheet with a semi-rigid backing member within the cavity. Low pressure air within the plenum chamber jacks the load and is discharged through pin hole type perforations within the bottom sheet to create a thin air film. Foam strips within the plenum chamber and extending over a substantial lengthwise extent of the plenum chamber insure air distribution through the plenum chamber. Further, foam strips may be positioned within one of the plenum chamber and the backing member cavity along the sides thereof and outside of the semi-rigid sheet to effect padding and eliminate sharp edges which may interfere with X-ray radiation.

<CIT> relates to a gas cushion bearing means for separating two bodies in proximate relationship by a cushion of gas, comprising at least one flexible membrane interposed between the bodies and extending normally parallel to and along their interface, said membrane having an aperture therein and being joined to one body to define a peripheral joint which encompasses an area greater than the area of said aperture, said membrane curving from the points of attachment on the one body toward the other body and toward said aperture, so as to form an inflatable diaphragm which bows convexly toward the opposing body by introduction of pressurized gas behind the membrane, the aperture being of rounded form and the rim of said aperture comprising a free edge, said membrane being thereby so constituted that such inflation thereof places said rim in hoop tension while disposing the immediately surrounding portion of the membrane generally in a plane substantially parallel to the interface, thereby to form conjunctively with the opposing body a regulatory gas escape gap leading radially outward in different directions from said aperture, which gap is increased and decreased locally by flexure of the rim defining said aperture transversely of the interface responsively to changes in the differences of gas pressures acting locally against opposite faces of said membrane portion.

<CIT> concerns a low friction device for transferring patients from one surface to another. This system allows a patient to be immobilized on one supporting surface. The immobilized patient can then be transferred laterally onto the target modality using an air bearing that is thin, homogeneously radiolucent and compatible with a variety of diagnostic imaging and treatment modalities.

<CIT> discloses a patient transfer apparatus that includes an air bearing attached beneath an inflatable cushion which has peripheral chambers so that the peripheral portions fill before the central portions. A diverter valve enables the apparatus to tap into the pressurized air supply provided by a fluidized bed. A tri-fold patient transfer board has a pair of parallel spaced apart ribs extending in the longitudinal direction near the center line of each tri-fold section. <CIT> concerns air chamber-type air pallets, <CIT> discloses patient support systems and methods for transferring patients and controlling patient temperature, and <CIT> concerns a patient transfer sled. SUMMARY OF.

The invention is defined in the independent claim. Further advantageous embodiments are defined in the dependent claims.

Other objects and features will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the invention.

To assist those of skill in the art in making and using the disclosed patient transfer devices and associated systems methods, reference is made to the accompanying figures, wherein:.

When transporting patients from one piece of equipment to another (e.g., between modalities) during a medical procedure or between simulation and treatment, it is desirable to employ a low, or reduced, friction transfer device or system. As used herein, "low" or "reduced" friction will be understood by those of ordinary skill in the art to mean friction that is lowered or reduced by application of air bearings below patient transfer devices as compared to friction without application of the air bearings. Low friction transfer devices enable the safe transfer of a patient from one target modality to another.

For example, referring to <FIG>, the various stages of an exemplary method of moving a patient transfer device according to the present invention is provided. In <FIG> a patient transfer device <NUM> is located on the top surface of a transport device <NUM>, such as a patient trolley. The transport device <NUM> is maneuvered such that the top surface of the transport device <NUM> is adjacent to and at a similar elevation as the top surface of a target modality <NUM>, such as an MRI table. An air bearing <NUM> located underneath the top patient supporting surface of the patient transfer device <NUM> is inflated, thereby reducing the friction as it slides the transport device <NUM> to the target modality <NUM>, as illustrated in <FIG>.

By placing an air bearing between a patient supporting surface and a treatment device supporting structure (e.g. a computerized tomography (CT) couch, a linear accelerator couch, a trolley, or the like), the patient can be moved during a medical procedure, such as a CT, MRI, or PET scan, radiation therapy, brachytherapy, operating room procedures, emergency medical services, etc., in an easy and safe manner for both the patient and the operator moving the patient.

It can be disadvantageous, however, to raise a patient supporting surface too high with an air bearing, to use air bearings that are too thick, or to use air bearing devices that are not uniformly radiolucent due to the use of tubing and pockets, or both. By using air bearing devices that take up too much height, the patient access to treatment machines can be limited. As a further example, if air bearing devices can jostle the patient, they can cause inaccuracies to occur in the position of the patient. In addition, some air bearing devices can be unstable, causing the air bearing device to be unsafe and uncomfortable for the patient.

The non-uniform radiolucent properties of some air bearing devices can cause additional problems. For example, a lack of uniformity or homogeneity under X-ray results in X-ray artifacting when images are taken of the patient. A lack of uniformity can also hinder or make it impossible to treat the patient through the support system with high energy X-radiation (such as linear accelerators) or particle beam radiation (such as proton therapy). In particular, extremely low attenuation and homogeneity is desired for transport systems to effectively provide treatment.

The patient transfer devices according to the present invention may be used in a wide variety of applications to facilitate the movement of a living being, such as by transfer of a patient. It will be appreciated by one of skill in the art that transfer devices according to aspects of this invention can be utilized in the many applications described herein as well as other applications.

For example, the devices according to the present invention may be used individuals in the field to assist the support or movement of living beings, such as for example by emergency responders to retrieve a patient involved in an accident. Such assistance may be desirable in connection with sporting injuries, automobile accidents, home injuries, or other instances in which support, transfer, or transportation of a living being may be needed or desired.

Upon arriving at a hospital or other medical treatment center or destination, the patient transfer devices may be used to transfer the injured patient to a target modality. For example, a patient may be transferred among mobile or fixed surfaces for treatment, diagnosis, rest or rehabilitation.

Patients are not limited to human patients. The patient transfer devices according to the present invention may also be used for veterinary medical applications for animals requiring transfer among or between diagnostic tests, laboratory analyses, and therapeutic procedures, including, but not limited to surgery.

The present invention is directed to exemplary patient transfer devices and associated systems and methods which provide a low or reduced friction transfer of the patient between modalities. The low friction of the patient transfer devices can be compatible with a variety of imaging and treatment modalities. For example, the patient transfer devices can be used for radiation treatment and diagnostic imaging equipment. By using the same patient transfer device during preparation and treatment of the patient, hospitals and treatment centers can have better utilization of equipment and higher patient throughput which, in turn, lowers costs and provides faster patient care.

The patient transfer devices, systems, and methods discussed herein are designed for positioning, transportation, and treatment of patients for a variety of medical procedures, e.g., radiation therapy, diagnostic imaging, or the like. For example, the patient transfer devices can be used for moving positioned or immobilized patients via a low friction interface to allow transfer of the patient from a trolley to a variety of target modalities.

In particular, the patient transfer devices provide a low friction interface comprised of an air bearing that is thin, presents low attenuation to radiation, and has homogeneous attenuation. It is preferred that patient transfer device according to the present invention exhibit a low WET (water equivalent thickness) value for low attenuation to radiation for imaging and treatment. For example, in a preferred embodiment, the patient transfer device may have a WET value that is less than <NUM> at <NUM> mV photons.

The various embodiments of the patient transfers devices according to the present invention also preferably exhibit little to no artifacting for x-ray usage, in other words, maximum X-ray translucency. The substantial reduction or elimination of X-ray artifacts allows the patient transfer device to act as a combination of a patient bearing device and a patient transfer device and can be compatible with a variety of diagnostic imaging and treatment modalities. In some embodiments, the patient transfer device can be constructed from materials that are compatible with a variety of medical equipment, e.g., magnetic resonance imaging (MRI) machines, and the like. In some embodiments, the air bearing can be detachable from the bottom surface of the patient transport device such that the air bearing can be easily replaced due to wear, contamination, or other reasons. When attached to the bottom surface of the homogeneous patient transfer device that is radiolucent, non-artifacting, and MRI or proton therapy compatible, the air bearing design does not compromise these features, thereby permitting accurate treatment of the patient.

It is an aspect of the present invention to provide a patient transfer device that enables air distribution under a bottom surface of the device to facilitate the formation of an air bearing. It is preferred that the patient transfer devices according to the present invention comprise a rigid structure upon which the patient rests for accurate patient positioning when the air bearing is inactive. The weight of a patient on top of a rigid patient transfer device, however, has the potential to depress the transfer device against the supporting surface upon which it rests and may block or inhibit the flow of air under the bottom surface of the patient transfer device. In other words, the flow of air may be inadvertently "pinched off" in such a way as to inhibit or prevent air flow to at least some locations beneath the bottom surface of the device. As a result, it may be difficult or impossible to generate an air bearing because the air pressure delivered underneath the bottom surface of the patient transfer device is unable to overcome the pressure exerted by the weight of the patient at particular points. In order to facilitate the flow of air, it is an aspect of the present invention to provide one or more air passageways that are either defined or otherwise located underneath the bottom surface of the patient transfer device.

In an embodiment of the present invention, the air passageways may be defined by the bottom surface of the patient transfer device. For example, the air passageways may be provided in the form of a contoured feature, a sculpted surface, a recess, a groove, or another surface that at least partially defines a passageway associated with the bottom surface. In other embodiments, the air passageways may be provided by using one or more spacers to define a space or gap between the bottom surface of the device and the support surface on which it rests. For example, one or more spacers can be positioned about the periphery of the bottom surface of the patient transfer device or at one or more locations of the bottom surface of the patient transfer device. The spacers may be in the form of contours, feet, pegs, or any other structure capable of maintaining a space between at least a portion of the bottom surface of the patient transfer device and a surface on which it rests.

The bottom surface of the various embodiments of the patient transfer device according to the present invention may then be covered with either a rigid or flexible cover having one or more apertures, such that when air is delivered between the bottom surface of the patient transfer device and the cover, an air bearing is formed.

In preferred embodiments of the invention, two covers or layers may be provided under the bottom surface of the patient transfer device, wherein the bottom layer is perforated and the two layers are sealed to each other at least around their peripheries to form a bladder. Delivering air to the bladder will expand the bladder and provide an air bearing. The use of a bladder is preferred because the lift provided by a bladder may facilitate transfer over a lip if the heights of the modalities differ. In other words, the expansion of the bladder raises the patient support component of the patient transfer device to an elevation above such a lip, thereby reducing or eliminating any interference as the patient transfer device is slid from one surface or modality to another. Additionally, a bladder may also be releasably attached to the patient support component of the patient transfer device such that it can be easily removable to allow for easy repair, replacement, cleaning, and/or disposal. The use of a bladder also provides the option to incorporate an air inlet or valve either in the top surface of the patient transfer device (e.g., passing into and/or through the patient support component of the patient transfer device) or directly in the bladder such as in a location that extends to a location outside the perimeter edge of the top surface of the patient transfer device.

With reference to <FIG> and <FIG>, top and bottom views of an exemplary patient transfer device <NUM> are provided. In particular, <FIG> shows a top surface <NUM> of the patient transfer device <NUM> that is configured to support a patient thereon and <FIG> shows a bottom surface <NUM> of the patient transfer device <NUM> that may be configured to face a support surface of a modality (not shown). The patient transfer device <NUM> can be fabricated from one or more of a variety of materials, such as carbon fiber, non-conductive fibers, fiberglass, polymer(s), or the like. In some embodiments, the patient transfer device <NUM> can be fabricated of a composite structure including one or more rigid outer skins or surfaces separated by an internal foam or honeycomb core. For example, an internal foam or honeycomb core can reduce the weight of the patient transfer device <NUM> while maintaining the structural stability of the patient transfer device <NUM>. In some embodiments, the patient transfer device <NUM> can include a structural, low-density foam with thin composite skins or outer surfaces surrounding the foam. The patient transfer device <NUM> can therefore define a substantially rigid structure. This configuration can minimize the amount of attenuation of a radiation treatment beam caused by the patient treatment device <NUM>.

With reference to <FIG>, the top surface <NUM> of the patient transfer device <NUM> can define a width <NUM> and a length <NUM> dimensioned to support a patient thereon. In some embodiments, the top surface <NUM> can define a substantially planar surface on which the patient can be positioned. In some embodiments, the top surface <NUM> can define a curved, concave surface configured to receive the patient thereon. For example, the top surface <NUM> can include a downwardly curved surface spaced from the edges of the patient transfer device <NUM> configured in the shape of the human body such that excessive motion of the patient on the patient transfer device <NUM> can be reduced. Although illustrated as defining a substantially rectangular configuration, in some embodiments, the patient transfer device <NUM> can define alternative configurations.

The patient transfer device <NUM> includes a first end <NUM>, e.g., a proximal end, and a second end <NUM>, e.g., a distal end. The patient transfer device <NUM> can be configured such that the head of a patient is positioned at or near the first end <NUM> and the feet of the patient extend in the direction of the second end <NUM>. The patient transfer device <NUM> further includes side edges <NUM>, <NUM> which extend lengthwise between the first and second ends <NUM>, <NUM>. In some embodiments, the side edges <NUM>, <NUM>, the first and second ends <NUM>, <NUM>, or both, can include handles for gripping and handling the patient transfer device <NUM>.

In some embodiments, the one or both of the side edges <NUM>, <NUM> include grooves <NUM> formed therein to assist in securing or immobilizing the patient with, e.g., straps, relative to the patient transfer device <NUM>. In some embodiments, the patient transfer device <NUM> can include indexing means, e.g., marks or dimensions <NUM>, openings or holes <NUM>, combinations thereof, or the like, for indexing the patient to the patient transfer device <NUM>. The openings or holes <NUM> can be of a variety of sizes and allow the patient to be secured to the patient transfer device <NUM>. For example, the openings or holes <NUM> can be configured to receive securing means therein for securing straps holding the patient. The indexing means thereby allow for accurate and repeatable placement of the patient on the patient transfer device <NUM>.

With reference to <FIG>, the bottom surface <NUM> includes one or more integrally sculpted regions or recesses which allow air to pass along the bottom surface <NUM> of the patient transfer device <NUM>. The integrally sculpted regions or recesses form an integrally sculpted configuration that is defined by the bottom surface <NUM> of the patient transfer device <NUM>. In some embodiments, the patient transfer device <NUM> can include a variety of sculpting configurations defined by the bottom surface <NUM> in different regions of the bottom surface <NUM> to achieve the requisite air flow for creating a low friction interface with a support surface. The different sculpting configurations can ensure that sufficient air flow is passed to areas of the patient transfer device <NUM> requiring greater support due to placement of the patient on the top surface <NUM>. In some embodiments, the patient transfer device <NUM> can include an internal pump <NUM> located within the patient transfer device <NUM> for passing air flow at or below the bottom surface <NUM>. In some embodiments, the patient transfer device <NUM> can be connected to an air source <NUM>, e.g., a pump, configured to pass air flow at or below the bottom surface <NUM>.

In the embodiment shown in <FIG>, the patient transfer device <NUM> includes three distinct sculpted sections or passages defined by the bottom surface <NUM>, e.g., a first section <NUM>, a second section <NUM>, and a third section <NUM>, formed in or defined by the bottom surface <NUM>. The first, second and third sections <NUM>, <NUM>, <NUM> can be configured to pass and distribute air flow along the desired portions along and below the bottom surface <NUM> of the patient transfer device <NUM>. In the embodiment shown in <FIG>, the first, second and third sections <NUM>, <NUM>, <NUM> can be different in configuration and size. <FIG> shows a cross-sectional view of the first section <NUM>, <FIG> shows a cross-sectional view of the second section <NUM>, and <FIG> shows a cross-sectional view of the third section <NUM>.

For example, with reference to <FIG> and <FIG>, the first section <NUM> can define a substantially rectangular configuration. In some embodiments, the first section <NUM> can define a substantially concave form <NUM> inwardly directed toward the top surface <NUM>. In particular, the first section <NUM> can define one continuous, substantially concave form <NUM>. In some embodiments, the thickness of the first section <NUM>, e.g., the distance between the top and bottom surfaces <NUM>, <NUM> at a central portion of the first section <NUM>, can be approximately <NUM>. In some embodiments, the first section <NUM> can be spaced from the first end <NUM> and the side edges <NUM>, <NUM> of the patient transfer device <NUM>. In some embodiments, the first section <NUM> can extend between the edges <NUM>, <NUM> of the bottom surface <NUM>. The first section <NUM> can thereby define a width substantially similar to or slightly smaller than the width <NUM> of the patient transfer device <NUM>. It should be understood that air passes along the concave form of the bottom surface <NUM>.

In some embodiments, the first section <NUM> can extend longitudinally across and encompass approximately seventy percent of the bottom surface <NUM> of the patient transfer device <NUM>. In some embodiments, the first section <NUM> can extend across and encompass the area corresponding to the portion of the top surface <NUM> on which the upper body (or the majority of the body) of the patient is positioned. Thus, the first section <NUM> can be located below the area of the top surface <NUM> typically scanned during medical procedures, thereby representing the imaging or treatment area. Due to the location of the first section <NUM>, the first section <NUM> can be minimally sculpted and includes substantially smooth and minimally curved surfaces such that imaging artifacts can be minimized or prevented. Attenuation can thereby be substantially homogenous for treatment, e.g., diagnostic imaging and radiation therapy treatment beams, static X-ray scanning, CT imaging scanning, or the like.

With reference to <FIG> and <FIG>, the second section <NUM> can define recesses in the form of two substantially concave grooves <NUM>, <NUM> which extend lengthwise or longitudinally along the length <NUM> of the patient transfer device <NUM>. Since the second section <NUM> is located below the imaging or treatment area, the greater curvature of the grooves <NUM>, <NUM> relative to the first section <NUM> does not affect the quality or effectiveness of the imaging or treatment. In some embodiments, the second section <NUM> can extend across approximately fifteen percent of the bottom surface <NUM> of the patient transfer device <NUM>. The two grooves <NUM>, <NUM> of the second section <NUM> can be spaced apart relative to each other by a separation <NUM> such that the width defined by the second section <NUM> is dimensioned smaller than the width of the first section <NUM>. In some embodiments, the width defined by the second section <NUM> can be approximately half of the width defined by the first section <NUM>. The second section <NUM> can connect the first section <NUM> with the third section <NUM> such that air flow passes therebetween.

With reference to <FIG> and <FIG>, the third section <NUM> can define a substantially rectangular configuration. In some embodiments, the third section <NUM> can extend across and encompass approximately twenty percent of the bottom surface <NUM> of the patient transfer device <NUM>. In some embodiments, the third section <NUM> can define a substantially concave form. In some embodiments, the third section <NUM> can define inwardly directed, curved edges <NUM>, <NUM> and a substantially flat bottom surface <NUM>. The width defined by the third section <NUM> can be dimensioned substantially similar to the width defined by the second section <NUM>. Since the third section <NUM> is located below the imaging or treatment area, the greater curvature of the curved edges <NUM>, <NUM> relative to the first section <NUM> does not affect the quality or effectiveness of the imaging or treatment.

In some embodiments, air flow can initially be introduced below the bottom surface <NUM> and the integrally sculpted configuration defined by the bottom surface <NUM> into the first section <NUM>. As the air flow passes and at least partially fills the first section <NUM>, the air flow can travel through and at least partially fill the second section <NUM>. The air flow can further travel into and at least partially fill the third section <NUM>. In some embodiments, air flow can initially be introduced into the third section <NUM>, thereby at least partially filling the third section <NUM> before passing to the second and first sections <NUM>, <NUM>. In some embodiments, air flow can be introduced simultaneously into the first, second and third sections <NUM>, <NUM>, <NUM>.

With reference to <FIG>, the patient transfer device <NUM> can include at least one cover <NUM>, e.g., a skin, attached thereto. In some embodiments, the cover <NUM> can be fixedly secured to the sides <NUM>, <NUM> of the patient transfer device <NUM> which define the thickness of the patient transfer device <NUM>, the bottom surface <NUM>, or both. In some embodiments, the cover <NUM> can be detachably secured to the sides <NUM>, <NUM>, the bottom surface <NUM>, or both, such that the cover <NUM> can be removed from the patient transfer device <NUM> for, e.g., cleaning, replacement, repair, and the like. The cover <NUM> can be secured to the patient transfer device <NUM> with, e.g., VELCRO®, fasteners, welding, stitching, one or more adhesives, double-sided tape, a seal, o-ring(s), combinations thereof, or the like. The cover <NUM> can be fabricated from at least one of a rigid material, a flexible material (such an elastomeric material), a coated fabric material, or the like. In some embodiments, the flexible material or the coated fabric material can be stretched across the bottom surface <NUM> of the patient transfer device <NUM> to prevent creases or folds in the cover <NUM>. The reduction in creases or folds in the cover <NUM> ensures an efficient passage of air flow along or below the bottom surface <NUM>. In some embodiments, the rigid material for fabrication of the cover <NUM> can be, e.g., carbon fiber, non-conductive fibers, a polymer, fiberglass, a non-conductive composite sheet, or the like.

The cover <NUM> can include a planar bottom surface <NUM> and flaps <NUM>, <NUM> extending from opposing side edges of the planar bottom surface <NUM> for attachment of the cover <NUM> to the sides <NUM>, <NUM> of the patient transfer device <NUM>. The cover <NUM> can be placed along and stretched across the bottom surface <NUM> of the patient transfer device <NUM> such that the cover <NUM> overlaps a majority of the bottom surface <NUM>. In some embodiments, the cover <NUM> can extend across and cover the entire bottom surface <NUM> of the patient transfer device <NUM>.

By securing the cover <NUM> along the bottom surface <NUM> of the patient transfer device <NUM>, a substantially sealed cavity <NUM>, e.g., a space, a bladder, or the like, can be formed between the bottom surface <NUM> and the cover <NUM>. The cover <NUM> further includes one or more perforated regions (see, e.g., <FIG>) through which air flow can pass. For example, the cover <NUM> can include one or more perforated regions and one or more unperforated regions. In particular, the cover <NUM> allows introduced air to travel through the cavity <NUM> and be distributed along the first, second and third sections <NUM>, <NUM>, <NUM>. The perforated regions in the cover <NUM> further allow the escaping air flow to create an air bearing against a supporting surface, e.g., a CT scan table, or the like, such that at least a portion of the patient transfer device <NUM> can be supported for movement along the supporting surface.

With reference to <FIG>, in some embodiments, the patient transfer device <NUM> can include a second cover <NUM>, e.g., an internal skin, a second skin, etc., attached thereto. The second cover <NUM> can be fabricated from at least one of a rigid material, a flexible material (such as an elastomeric material), a coated fabric material, or the like. The second cover <NUM> generally does not include perforations. In some embodiments, the cover <NUM> can be fixedly or removably secured to the bottom surface <NUM>, the concave form <NUM>, the grooves <NUM>, <NUM>, the curved edges <NUM>, <NUM>, the bottom surface <NUM>, or combinations thereof. For example, the cover <NUM> can include a central section <NUM>, which conforms to the sculpted areas of the bottom surface <NUM>, and further includes side flaps <NUM>, <NUM> for attachment of the cover <NUM> to side edges of the bottom surface <NUM>. In particular, the cover <NUM> can be attached along the bottom surface <NUM> of the first, second and third sections <NUM>, <NUM>, <NUM> such that the cover <NUM> substantially conforms to and defines a complementary shape relative to the sculpted surfaces of the bottom surface <NUM>.

The external cover <NUM> can be attached to the patient transfer device <NUM> by overlapping at least a portion of the cover <NUM> as shown in <FIG>. For example, the covers <NUM>, <NUM> can be sealed relative to each other at the flaps <NUM>, <NUM> to form an internal cavity <NUM>, e.g., a space, a bladder, or the like, for distributing air along or below the bottom surface <NUM> of the patient transfer device <NUM>. Thus, air introduced into the cavity <NUM> can be selectively distributed through the first, second and third sections <NUM>, <NUM>, <NUM>, creating an air bearing to lift the patient and the patient transfer device <NUM> for movement. In particular, it should be understood that the flow of air passing through the perforations of the cover <NUM> can create an air bearing between the cover <NUM> and the supporting surface of the modality, and further provides sufficient force against the supporting surface to at least partially elevate the patient transfer device <NUM> above the supporting surface. A patient can thereby be safely positioned and immobilized on the patient transfer device <NUM> prior to creation of the air bearing, and the air bearing can be created when movement of the patient on the patient transfer device <NUM> from, e.g., imaging to treatment, is desired. The patient can therefore be moved on one transfer surface without affecting the orientation of the patient for treatment.

Referring to <FIG>, an embodiment is illustrated in which the patient transfer device <NUM> includes a rigid cover <NUM> that may be provided with one or more apertures (e.g., perforated). The embodiment also includes a bottom surface <NUM> that is recessed away from the rigid cover <NUM> and towards the top surface <NUM> of the patient transfer device <NUM>, thereby creating a passageway through which air may be delivered such that it is forced through the apertured rigid cover to provide an air bearing. The bottom surface <NUM> of this particular embodiment may or may not be curved. Also, the rigid cover <NUM> may or may not be integral with the patient transfer device, i.e., the rigid cover <NUM> may be a separate removable piece. Additionally, the passageway in such an embodiment may be formed by creating one or more internal passageways within an interior of an integral device.

In another embodiment illustrated in <FIG>, the bottom surface <NUM> is recessed towards the top surface <NUM> of the patient transfer device <NUM> by a plurality of spacers having a height that is greater than the thickness of the cover <NUM>, such as feet <NUM>, to provide a passageway beneath the bottom surface <NUM> of the patient transfer device <NUM>. In this particular embodiment, a cover <NUM> is optionally flexible and fastened to the beveled sides <NUM>, <NUM> of the patient transfer device <NUM>. The flexible cover <NUM> may be attached to the bottom surface <NUM> between and/or around the plurality of feet <NUM>, or openings may be provided in the flexible cover <NUM> through which the plurality of feet <NUM> may be inserted. The bottom of the feet <NUM> may optionally have a non-skidding material applied to their bottom surface, such as a rubber or other non-slip coating, to prevent the patient transfer device <NUM> from sliding across a target surface when the cover <NUM> is not inflated or when air is not being introduced into the cover <NUM>.

In other embodiments, such as the embodiment illustrated in <FIG>, the flexible cover <NUM> may be attached to the sides <NUM>, <NUM> of the patient transfer device <NUM> and extend underneath the bottom of the plurality of feet <NUM>. When air is introduced to the cover, the feet <NUM> prevent a blockage of the air passageway beneath the surface <NUM>, thus allowing the flow of air to various regions of the cover <NUM>.

In some embodiments that utilize the covers, skins, cavities, etc., passage of air below the bottom surface <NUM> of the patient transfer device <NUM> acts to inflate the cover or skin into the integrally sculpted configuration that is defined by the bottom surface <NUM>. The inflation of the cover or skin into the configuration defined by the bottom surface <NUM> may occur in embodiments where a single cover or skin or multiple covers or skins are utilized. In some embodiments, the cover or skin may be applied, such that the cover or skin expands away from the bottom surface <NUM>. For example in <FIG>, the cover <NUM> may be pulled taught against the bottom surface <NUM>. Upon inflation, the cover would expand away from the bottom surface <NUM> and lift the plurality of feet <NUM> off of the target surface. This configuration would provide the benefit of reducing or eliminating contact between the cover and the support surface, thereby preventing wear on the cover.

In a preferred embodiment, the patient transfer device includes an air bearing that comprises an air-receiving region, such as a bladder, having substantially no side walls. When not inflated or receiving air, the bladder is preferably substantially flat to provide a generally constant thickness that is essentially limited to the thickness of the layer or layers of material from which it is formed. This provides the benefit of reducing and/or eliminating the potential for wrinkles, which can affect the positioning accuracy of the patient on top and create artifacts during imaging and treatment. Preferably, the bladder is fabricated from two flat sheets of flexible material that are sealed to each other such as about their respective peripheries. This material may comprise, for example, a fabric coated with a thin layer of thermoplastic. By placing the two thermoplastic layers directly against each other, the sheets may be welded to each other through conventional means, such as ultrasonic or RF welding, thereby providing a robust and cost-effective manufacturing method. In this way, no additional material is introduced into the bladder that can affect imaging and treatment performance. Alternatively, the sheets may be adhesively bonded, stitched together, or attached by any other means familiar to one skilled in the art. The resulting two sheet air bearing bladder has excellent transfer properties in that it is able to cross relatively large gaps between the trolley and target modality (e.g., gaps up to <NUM> or more), as well as accommodate large differences between the vertical surface height of the trolley and target modality. The air bearings incorporated in the various systems of the present invention may also facilitate transfer between a level trolley and sloped target modality. For example, it is not uncommon for the table of a receiving modality to be two or three centimeters higher on one end versus the other (e.g., head end to foot end).

With reference to <FIG>, a bottom view of the patient transfer device <NUM> including the cover <NUM> is provided. As discussed above, the cover <NUM> includes a plurality of perforations <NUM>, e.g., regions of perforations <NUM>, and further includes one or more unperforated regions <NUM>. For example, the perforations <NUM> can be located in positions complementary to at least one of the first, second, or third sections <NUM>, <NUM>, <NUM> of the bottom surface <NUM>, and the unperforated regions <NUM> surround at least one of the first, second, or third sections <NUM>, <NUM>, <NUM>. Air flow can thereby be distributed and expelled out of the perforations <NUM> in areas which contribute to creating the air bearing for lifting the patient transfer device <NUM> (e.g., inflating the cover <NUM> into the integrally sculpted configuration defined by the bottom surface <NUM> of the patient transfer device <NUM>).

Turning now to <FIG>, an alternative patient transfer device <NUM> is shown. In particular, <FIG> shows a perspective, bottom view of the patient transfer device <NUM>. <FIG> shows a bottom view of the patient transfer device <NUM>. <FIG> shows a cross-sectional view of the patient transfer device <NUM>. <FIG> shows a cross-sectional view of the patient transfer device <NUM> including a cover. <FIG> shows a cross-sectional view of the patient transfer device <NUM> including two covers (e.g., a first skin and a second skin). It should be understood that the patient transfer device <NUM> can be substantially similar in structure and function to the patient transfer device <NUM>, except for the distinctions noted herein. As such, like structures are marked with like reference numbers.

Rather than including three different configurations of first, second and third sections <NUM>, <NUM>, <NUM>, the patient transfer device <NUM> of <FIG> includes one sculpted section <NUM> defined by the bottom surface <NUM> for passage of air along or below the bottom surface <NUM>. The section <NUM> can be centrally positioned and spaced from the edges of the patient transfer device <NUM>, and can extend longitudinally from the first end <NUM> to the second end <NUM>. The section <NUM> can define a substantially rectangular outer perimeter <NUM>. However, it should be understood that alternative configurations of the outer perimeter <NUM> can be used.

Within the outer perimeter <NUM>, the section <NUM> includes one or more longitudinal passages <NUM> extending from a first end <NUM> to a second end <NUM> of the perimeter <NUM> along the length <NUM> of the patient transfer device <NUM>, e.g., substantially parallel to the length <NUM> of the patient transfer device <NUM>. In some embodiments, the patient transfer device <NUM> includes an air source <NUM>, e.g., a pump with an outlet, an air outlet connected to an external air source, or the like, adjacent to or at the second end <NUM>. The centrally located longitudinal passages <NUM> can therefore extend from the first end <NUM> to the air source <NUM>. The longitudinal passages <NUM> can define substantially concave grooves connected relative to each other at raised connecting portions <NUM>. In some embodiments, the connecting portions <NUM> can define pointed edges. In some embodiments, the connecting portions <NUM> can define rounded edges.

The longitudinal passages <NUM> can be in fluid communication with the air source <NUM> such that air flow can be introduced into the longitudinal passages <NUM> to flow along and below the bottom surface <NUM>. As shown in <FIG>, the patient transfer device <NUM> can include a cover <NUM>, a cover <NUM>, or both. In some embodiments, the cover <NUM> can be positioned along the bottom surface <NUM> such that the inside surface of the cover <NUM> abuts the connecting portions <NUM> between the longitudinal passages <NUM>, thereby isolating each longitudinal passage <NUM> relative to the other longitudinal passages <NUM>. In such embodiments, air flow can be introduced separately into each of the longitudinal passages <NUM> and perforations can be formed in the cover <NUM> in areas corresponding to each longitudinal passage <NUM> to create the desired air bearing. The passage of air below the bottom surface <NUM> may inflate the covers <NUM>, <NUM> into the longitudinal passages <NUM> (e.g., the integrally sculpted configuration defined by the bottom surface <NUM>), thereby creating the air bearing. In some embodiments, the cover <NUM> can be positioned along the bottom surface <NUM> such that a separation <NUM> exists between the inner surface of the cover <NUM> and the connecting portions <NUM>. Air can thereby be introduced from one or more sources into the cavity <NUM> and the separation <NUM> allows the air flow to be distributed to each of the longitudinal passages <NUM>.

It should be understood that the number of and/or configuration of the longitudinal passages <NUM>, e.g., air passages (the integrally sculpted configuration defined by the bottom surface), can be determined based on a reduction of image artifacts during imaging, e.g., CT imaging, or the like. The size of the individual longitudinal passages <NUM> can be varied. For example, in some embodiments, the size of each of the longitudinal passages <NUM> can be substantially similar. In some embodiments, the size of some of the longitudinal passages <NUM> can be smaller or greater than the other longitudinal passages <NUM>. In some embodiments, the size of the longitudinal passages <NUM> can be selected based on the rate of air flow desired in the longitudinal passages <NUM>. Thus, although six longitudinal passages <NUM> are shown in <FIG>, it should be understood that the number and/or depth of the longitudinal passages <NUM> can be optimized to provide sufficient air flow for creation of an air cushion with which the patient can be transferred on the patient transfer device <NUM>. In some embodiments, areas along the bottom surface <NUM> can be selectively formed without longitudinal passages <NUM>.

Minimization of artifacting can be achieved by appropriately designing the shape or configuration of the integrally sculpted regions defined by the bottom surface <NUM>. In some embodiments, a radii of approximately <NUM> of each longitudinal passage <NUM> can produce the desired results in terms of a reduction in artifacting. In some embodiments, the implementation of large radii, e.g., as large as possible without artifacting, allows the thickness of the patient transfer device <NUM> to define a minimum variation, thereby minimizing the effect on attenuation homogeneity. Shapes such as ellipses, complex curvatures, contours, and the like can also be employed such that the sculpted surface does not produce artifacts during imaging.

Turning now to <FIG>, an alternative patient transfer device <NUM> is shown. In particular, <FIG> shows a bottom view of the patient transfer device <NUM> and <FIG> shows a cross-sectional view of the patient transfer device <NUM>. It should be understood that the patient transfer device <NUM> can be substantially similar in structure and function to the patient transfer devices <NUM>, <NUM>, except for the distinctions noted herein. As such, like structures are marked with like reference numbers.

In particular, rather than including six longitudinal passages <NUM>, the patient transfer device <NUM> of <FIG> includes four longitudinal passages <NUM>. The longitudinal passages <NUM> can be dimensioned greater in width as compared to the longitudinal passages <NUM> of the patient transfer device <NUM> to ensure that the longitudinal passages <NUM> cover a sufficient portion of the width <NUM> of the patient transfer device <NUM>. The greater width of the longitudinal passages <NUM> can vary the flow of air through the longitudinal passages <NUM> as compared to the flow of air in the patient transfer device <NUM>. Although illustrated without covers, it should be understood that cover <NUM>, cover <NUM>, or both, can be attached to the patient transfer device <NUM>.

Turning now to <FIG>, an alternative patient transfer device <NUM> is shown. In particular, <FIG> shows a bottom view of the patient transfer device <NUM> and <FIG> shows a cross-sectional view of the patient transfer device <NUM>. It should be understood that the patient transfer device <NUM> can be substantially similar in structure and function to the patient transfer devices <NUM>, <NUM>, <NUM>, except for the distinctions noted herein. As such, like structures are marked with like reference numbers.

In particular, the patient transfer device <NUM> includes three sections for passage of air flow, e.g., a first section <NUM>, a second section <NUM>, and a third section <NUM>. Rather than each section extending only a portion of the length <NUM> of the patient transfer device <NUM> (see, e.g., the patient transfer device <NUM>), the first, second and third sections <NUM>, <NUM>, <NUM> of the patient transfer device <NUM> can extend substantially similar longitudinal distances along the length <NUM>.

In some embodiments, the first section <NUM> can be centrally located between the second and third sections <NUM>, <NUM>. The first section <NUM> can define a substantially planar or partially concave surface along which air can flow. In some embodiments, the first section <NUM> can be substantially devoid of air flow and air can be introduced only to the second and third sections <NUM>, <NUM> such that an air bearing is created on opposing sides of the patient transfer device <NUM>.

For example, the second and third sections <NUM>, <NUM> can be substantially similar in structure and function and are positioned on opposing sides of the first section <NUM>. In particular, the second and third sections <NUM>, <NUM> can extend parallel to and spaced from the side edges <NUM>, <NUM>. In some embodiments, the second and third sections <NUM>, <NUM> can extend approximately ninety percent of the length <NUM> of the patient transfer device <NUM>. Although shown as extending only along the sides of the patient transfer device <NUM>, in some embodiments, the second and third sections <NUM>, <NUM> can extend along a substantial portion of the perimeter of the bottom surface <NUM> such that an air bearing can be created along the perimeter of the patient transfer device <NUM>.

The second and third sections <NUM>, <NUM> can be substantially similar to the longitudinal passages <NUM> discussed above. It should be understood that each of the second and third sections <NUM>, <NUM> can include one or more longitudinal passages <NUM> joined at connecting portions <NUM>. Thus, air flow introduced into the second and third sections <NUM>, <NUM> can create an air bearing near the edges <NUM>, <NUM> of the patient transfer device <NUM> for movement of the patient. Although illustrated without covers, it should be understood that cover <NUM>, cover <NUM>, or both, can be attached to the patient transfer device <NUM>.

With reference to <FIG>, in some embodiments, the top surface <NUM> of the patient transfer device <NUM> can define a substantially concave form. The concave form allows the thickness of the center of the patient transfer device <NUM> to be minimized, thereby allowing the patient to be positioned closer to the bottom surface <NUM>. The minimized thickness of the patient transfer device <NUM> can be advantageous in a variety of medical procedures. For example, when patients are imaged using MRI, an antenna coil can be placed under the patient supporting surface and/or the patient transfer device <NUM>.

By minimizing the thickness of the patient transfer device <NUM>, the patient can be positioned closer to the coil, resulting in higher quality images. The minimized thickness can also be beneficial for alternative treatment techniques, such as brachytherapy. In some embodiments, the thickness of the central longitudinal region of the patient transfer device <NUM> can be approximately <NUM> or less. In some embodiments, the thickness of the central longitudinal region of the patient transfer device <NUM> can be approximately <NUM> or less. In some embodiments, the thickness of the central longitudinal region of the patient transfer device <NUM> can be approximately <NUM> or less.

Referring next to <FIG>, a patient transfer device <NUM> is depicted. <FIG> depicts the top surface of the device <NUM>, <FIG> depicts the bottom surface <NUM> of the patient transfer device <NUM>, and <FIG> is a cross-sectional view of the patient transfer device <NUM>. It should be understood that the patient transfer device <NUM> can be substantially similar in structure and function to the patient transfer devices <NUM>, <NUM>, <NUM>, <NUM> except for the distinctions noted herein. As such, like structures are marked with like reference numbers.

The patient transfer device <NUM> additionally includes an indexing aperture <NUM> that extends through the top surface <NUM> and the bottom surface <NUM> and provides additional indexing accuracy. The bottom surface <NUM> includes an integrally sculpted configuration <NUM> that defines a recess. The configuration <NUM> forms a single longitudinal passage <NUM> that extends along the bottom surface <NUM>. Although not depicted, the bottom surface <NUM> may include a cover, or multiple covers, such that the covers inflate into the configuration <NUM> when air flow is passed below the bottom surface <NUM>.

Referring next to <FIG>, another embodiment of a patient transfer device <NUM> is shown. <FIG> shows the bottom surface <NUM> of the device <NUM>, and <FIG> are various cross-sectional views of the device <NUM>. It should be understood that the patient transfer device <NUM> can be substantially similar in structure and function to the patient transfer devices <NUM>, <NUM>, <NUM>, <NUM>, <NUM> except for the distinctions noted herein. As such, like structures are marked with like reference numbers.

Defined by the bottom surface <NUM> of the patient transfer device <NUM> is a recess shaped by an integrally sculpted configuration <NUM>. The configuration <NUM> defines two recesses in the form of two sections <NUM>, <NUM> that extend along the bottom surface <NUM> and that are separated by a center section <NUM>. When air is passed below the bottom surface <NUM>, the air may enter the sections <NUM>, <NUM> while the center section <NUM> remains devoid of air flow. As depicted in <FIG>, a single cover <NUM> may be utilized such that when air is passed below the bottom surface <NUM>, the cover <NUM> may create the air bearing. Alternatively, a pair of covers <NUM>, <NUM> may be used such that the intermediate cover <NUM> extends into the sections <NUM>, <NUM> when air is delivered between the covers <NUM>, <NUM>, as illustrated in <FIG>. The patient transfer device <NUM> may also include a beveled edge <NUM> to provide an attachment surface for the cover <NUM>. Any attachment means may be incorporated on the beveled edge <NUM> and the beveled edge <NUM> may be conformed to any suitable angle. For example, a touch fastener may be applied to the beveled edge <NUM>, as well as the perimeter edge region of the cover <NUM>. When using a touch fastener, the beveled edge <NUM> may be preferably about <NUM> degrees relative to the surface upon which the patient transfer device rests.

The longitudinal recesses <NUM>, <NUM> communicate with one another by transverse recesses that may be positioned at any location along the length of the patient support. For example referring to <FIG>, another embodiment of a patient transfer device <NUM> is shown, which includes longitudinal recesses <NUM>, <NUM>, <NUM>, <NUM> that are in fluid communication via two transverse recesses located at the head and foot of the patient transfer device <NUM> (above indexing groove <NUM> and below indexing groove <NUM>). The patient transfer device may also include a set of transverse indexing grooves <NUM>, <NUM>, <NUM> to ensure air is not cut off when an indexing feature is used to locate the patient transfer surface <NUM>. In <FIG>, an example of an indexing feature <NUM> is inserted into the middle indexing groove <NUM> of patient transfer device <NUM>. Referring to <FIG>, the indexing feature <NUM> includes a base section <NUM>, and it is preferred that the height of the indexing groove <NUM> is greater than the height of the base section <NUM> to allow air to travel between the bottom surface of the patient transfer device <NUM> and the top of the base section <NUM>, so that the longitudinal recesses <NUM>, <NUM> may receive the air on either side of the indexing feature <NUM>. All of the recesses may be provided in any variety of straight, curved, or angled configurations.

With reference to <FIG>, an embodiment of a patient transfer device <NUM> is shown. <FIG> shows the bottom surface <NUM> of the patient transfer device <NUM>, and <FIG> is a cross-sectional view of the patient transfer device <NUM>. It should be understood that the patient transfer device <NUM> can be substantially similar in structure and function to the patient transfer devices <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> except for the distinctions noted herein. As such, like structures are marked with like reference numbers.

The patient transfer device <NUM> includes an integrally sculpted configuration <NUM> forming recesses defined by the bottom surface <NUM>. The configuration <NUM> includes two recesses in the form of sections <NUM> and <NUM>, with each section having two longitudinal passages that extend along the bottom surface <NUM>. The sections <NUM> and <NUM> are separated by a center section <NUM>. When air is passed below the bottom surface <NUM>, it may enter the two sections <NUM> and <NUM> to create the air bearing, with the center section <NUM> being substantially devoid of air flow. Although not depicted, the device <NUM> may include a single cover or multiple covers, such that the passage of air flow inflates the covers into the longitudinal passages of the sections <NUM>, <NUM>.

The sculpting of the regions/configurations defined by the bottom surface <NUM> as described herein can be any shape desired for particular medical applications, e.g., domed, semi-circular, combinations thereof, and the like. In some embodiments, the sculpting can include slightly concave curvatures such that artifacting can be minimized in the patient image for, e.g., static X-ray scan, CT scans, and the like. In some embodiments, the depth of the concave sculpting may be approximately <NUM> or less, more preferably approximately <NUM> or less. The depth of the concave sculpting may also be optimized to minimize the impact the sculpting has on treatment beam attenuation.

Thus, the patient transfer devices disclosed herein can be advantageously used to position or immobilize the patient for imaging, to transport the patient between modalities for treatment, and to maintain the proper patient orientation during treatment. For example, the patient transfer devices can be used for a variety of medical treatments, e.g., head and neck cancer, lung cancer, breast cancer, prostate cancer, and the like, via external beam radiation therapy, internal beam radiation therapy, or both.

Although the patient transfer devices have been described for use in radiation therapy and associated imaging, it should be understood that the patient transfer devices can also be used in other applications for transporting patients. For example, situations where a patient is incapable of moving from one patient support device to another under their own power can be made easier through the use of the disclosed patient transfer devices. As a further example, these situations can occur in emergency room environments in which the patient must be taken to a CAT scan or MRI in order to diagnose their injury. In one possible scenario, the patient can be placed on a patient transfer device upon arriving at the hospital. After entering the hospital, the patient can be transported to the imaging room and transferred to the couch top of the imaging modality. By using the patient transfer device, stress on the patient and the staff can be minimized by reducing the amount of lifting and manipulation required to transport the patient.

While exemplary embodiments have been described herein, it is expressly noted that these embodiments should not be construed as limiting, but rather that additions and modifications to what is expressly described herein also are included within the scope of the invention. Moreover, it is to be understood that the features of the various embodiments described herein are not mutually exclusive and can exist in various combinations and permutations, even if such combinations or permutations are not made express herein, without departing from the spirit and scope of the invention.

<FIG> is a perspective view of another embodiment of a patient transfer device, illustrated on a trolley according to one aspect of this invention. <FIG> illustrates a patient transfer device <NUM> positioned on a trolley <NUM>. Trolley <NUM> is one example of a modality according to one aspect of this invention. It is shown schematically for purposes of illustration, and may have many various configurations. Generally, trolley <NUM> provides a support surface on its top, over which the patient transfer device <NUM> is positioned.

<FIG> is an exploded view of the patient transfer device illustrated in <FIG>. <FIG> shows various components of the patient transfer device <NUM> illustrated in <FIG>. Patient transfer device <NUM> includes a patient support <NUM> that is coupled or otherwise associated with a bladder <NUM>. The patient support <NUM> is formed from a material that is relatively rigid as compared to the bladder <NUM>. It can be formed from a variety of substantially rigid materials. It is preferably radiolucent or X-Ray homogenous.

Bladder <NUM> may include a valve <NUM> through which air can pass to an interior region defined by the bladder <NUM>. The interior region may be defined by the bladder <NUM> and a surface of the patient support <NUM> if a single cover layer is used to form the bladder <NUM>. Alternatively, and as shown in this embodiment, the bladder <NUM> is formed from two cover layers.

The valve <NUM>, which includes a valve membrane <NUM>, may be a check valve permitting flow in one direction. For example it may be an umbrella style valve or any other suitable valve configuration. The valve <NUM> permits the flow of air into an interior region of the bladder <NUM> and may be provided in a wide variety of locations or configurations.

A hose coupling <NUM> is configured to be coupled to the end of an air hose, such as an air hose <NUM> illustrated in <FIG>. The hose is preferably flexible and can be selected from a wide variety of configurations.

A housing <NUM> is provided to receive the hose coupling <NUM>. It is shown in an open configuration in <FIG>. The housing <NUM> covers and encloses a latch <NUM> that is positioned to capture the hose coupling <NUM>. A mounting portion <NUM> is mounted to the patient support <NUM> by fasteners <NUM> that engage the mounting portion <NUM> via mounting holes <NUM>.

<FIG> is a top view of a valve cover component of the patient transfer device illustrated in <FIG>. <FIG> shows a top plan view of the housing <NUM> in a closed position. It can be provided in a wide range of shapes and sizes and configurations.

<FIG> is a side view of the valve and mounting portion of an air supply hose and illustrates the relationship of the hose coupling <NUM> before it is inserted into the latch <NUM> within the housing <NUM>.

<FIG> shows a cross-sectional side view of the valve portion of the patient transfer device illustrated in <FIG>, in an open position with an air supply line attached. <FIG> illustrates the hose coupling <NUM> in a latched configuration in which the latch <NUM> captures a shoulder of the hose coupling <NUM>. As illustrated in <FIG>, movement of the latch <NUM> from the left toward the right provides such engagement. The latch <NUM> may be biased into the position shown in <FIG> by a spring or other mechanism. A cover <NUM> is shown in an open position, thereby providing access for engaging the hose coupling <NUM> with the patient support <NUM>.

<FIG> shows a cross-sectional side view of the valve assembly shown in <FIG>, with the valve cover in a closed position. In <FIG>, the cover <NUM> is shown in a closed position. This position protects the latch <NUM> and also prevents contamination or dirt from entering into the area of the valve <NUM>.

<FIG> shows a plan view of a top side of a bladder of the patient transfer device illustrated in <FIG>. <FIG> shows the top cover layer <NUM> of the bladder <NUM> of the patient support <NUM>. The top cover layer <NUM> is provided with notches <NUM> that can be used for positioning or indexing purposes. Top cover layer <NUM> is also provided with a fastening mechanism such as hook and loop fasteners <NUM> that extend around the perimeter. More specifically, a fastener such as fasteners <NUM> extend around the outer perimeter of the top cover layer <NUM> to facilitate coupling, preferably releasable coupling, of the top cover layer <NUM> of the bladder <NUM> to the patient support <NUM>.

<FIG> shows a bottom plan view of the bladder illustrated in <FIG> shows the bottom cover layer <NUM> of the bladder <NUM>. Like the top cover layer <NUM>, bottom cover layer <NUM> has notches <NUM>. Bottom cover layer <NUM> also includes aperture groups <NUM> that are positioned generally to extend along the longitudinal direction of the bottom cover layer <NUM> along its sides. These aperture groups <NUM> include apertures through which air passes in order to provide an air bearing. The bottom cover layer <NUM> also includes a number of aperture lines <NUM> that extend generally in the width-wise direction. Finally, the bottom cover layer <NUM> includes a series of weld or bond lines <NUM> that also extend laterally along the width direction.

The weld or bond lines <NUM>, aperture lines <NUM>, and aperture groups <NUM> are positioned in such a way that the patient transfer device <NUM> can be moved from one surface to another while providing a substantial air bearing even when the patient transfer device passes over gaps between modalities or other openings through which air can escape. In other words, the apertures in the bottom cover layer <NUM> are positioned to provide the air bearing necessary to reduce friction between the patient transfer device and the support surface of the modalities such as trolley <NUM>.

The weld or bond lines <NUM> are positioned along the length of the bladder in such a way as to provide controlled resistance to the passage of air through the bladder. By selecting the length of the weld or bond lines <NUM> and the distance between the weld lines, the resistance to air flow can be varied such that air flow can be redirected, depending on the location along the bladder <NUM>. The weld and bond lines also restrain the bag in its inflated state, producing geometry that greatly improves stability and maximizes the effect of the air bearing.

More specifically, weld or bonds lines <NUM> have a length L and are separated by a distance D. By increasing the length L of the weld or bond lines <NUM>, greater resistance to airflow around the welds is created, thus resisting the flow of air from one end to the other along the length of the bladder <NUM>. In other words, shorter weld or bond lines <NUM> permit more air flow around the weld as compared to longer weld or bond lines <NUM>.

The distance D between weld lines is varied in order to control the inflation and height of the bladder <NUM> when air flow is traveling through the bladder's interior. For example, a smaller distance D results in less elevation of the bladder when inflated, while a greater distance D increases that elevation.

In <FIG>, a patient's head would typically be positioned at one end or the other of the patient transfer device <NUM>, and the orientation of the weld or bond lines <NUM>, aperture lines <NUM>, and aperture groups <NUM> would be selected accordingly. Also, the length L and distance D associated with the weld or bond lines <NUM> would be positioned in order to support various anatomies of a patient.

<FIG> show cover layers of an embodiment of a bladder before, during, and after being welded, respectively, according to another aspect of this invention. <FIG> shows two layers of a bladder <NUM>; namely, the top cover layer <NUM> and the bottom cover layer <NUM>. These aspects of the bladder <NUM> are shown schematically. Each of the layers <NUM> and <NUM> includes several sublayers according to one embodiment of this invention. For example, top cover layer <NUM> includes an outer layer 824A and an inner layer 824B. Similarly, bottom cover layer <NUM> includes an inner layer 830B and an out outer layer 830A.

As shown in <FIG>, a weld bar <NUM> can be utilized according to one aspect of this invention in order to bond or otherwise connect the top cover layer <NUM> to the bottom cover layer <NUM>. As illustrated in <FIG>, the layers are connected in such a way so that there is no other component in between them. In other words, in this embodiment, there is no baffle or wall extending from the bottom cover layer to the top cover layer. The resulting thickness of the bonded or welded bladder is simply the total thickness of the layers combined, approximately.

As shown in <FIG>, a weld or bond line <NUM> is provided as a result. The weld bar <NUM> shown in <FIG> can be maintained at a temperature sufficient to melt the inner layers 824B and 830B of the top cover layer <NUM> and <NUM>, respectively, while not melting the outer layers 824A and 830A.

A wide variety of materials can be used for the inner and outer layers of the top and bottom cover layers.

<FIG> shows yet another embodiment according to aspects of the invention, in which a patient support <NUM> and a bladder <NUM> are provided. Patient support <NUM> is similar to patient support <NUM>. The bladder <NUM>, however, differs from bladder <NUM> in that it is configured to have a portion extending beyond a perimeter of the patient support <NUM>. In this way, a valve <NUM> can be provided on the bladder <NUM> at a location that is spaced away from the patient support <NUM>. The air supply line may therefore be connected to an attachment point on the top surface <NUM> of a patient transfer device, as illustrated in <FIG>, or directly to the bladder <NUM>, as illustrated in <FIG>. The attachment point for the air supply line may also be provided in one or more different locations (A-G) on the top surface <NUM> of a patient support surface and have various sized dimensions or shapes, as illustrated in <FIG>. This provides additional flexibility for the handling of the air supply line and hose and the ability to accommodate different size hosing. While this extension of the bladder <NUM> is shown to extend from the head or foot end of the patient transfer device, it could also extend from the sides or from plural locations with multiple valves.

<FIG> shows a cross-sectional end view of yet another embodiment of a patient transfer device according to aspects of this invention. <FIG> is an example of a patient transfer device that includes a bladder formed from a single cover layer connected to the patient support. In this embodiment, the bladder is defined by the bottom surface of the patient support and the cover layer. It also illustrates the manner in which a perimeter portion of the bladder is connected to beveled surfaces of the patient support.

As shown in <FIG>, the patient support ideally has plural recesses extending along its length. With such a configuration, the central portion of the patient support can contact or bear against or be supported by a support surface, thereby supporting a central region of the patient support. Nevertheless, the recesses still provide access for air flow without pinching or otherwise obstructing the flow of air.

Although not shown, such longitudinal recesses communicate with one another by transverse recesses that may be positioned at any location along the length of the patient support. Also, the recesses can be provided in any variety of straight or curved or angled configurations.

<FIG> illustrates a cross-sectional end view of still another embodiment of a patient transfer device. <FIG> illustrates an embodiment similar to that in <FIG> but with a bladder formed from two cover layers. In this view, the bladder is inflated at least partially so as to separate the cover layers (or sheet or skin) of the bladder. For example, the upper cover layer extends upwardly into the recesses and against the bottom surface of the patient support. The lower cover layer is spaced from the upper cover layer, thereby defining a passage for the flow of air. As can be seen in <FIG>, the air flow passage is facilitated this way. Also, the cover layers of the bladder may be connected or coupled or otherwise sealed at their perimeter and then may be releasably or even permanently attached to the patient support at the beveled region as shown in <FIG>.

In one aspect of the present invention, the sculpted feature may mitigate the potential for the air bearing air passage from becoming pinched off. When the bottom surface of the transfer surface is flat, the air passage can become substantially constricted such that, upon starting delivery of air, it can never properly inflate. This prevents the transfer device from being able to lift the patient. The sculpted feature provides a low resistance channel through which air can always travel to initiate function of the air bearing. This feature also allows the transfer device to be able to be partially extended off an edge of the target modality patient table. For example, referring to <FIG> and <FIG>, a patient transfer device <NUM> according to one embodiment of the present invention is shown on the target surface of a modality <NUM>. Certain medical treatments or therapy may require the patient transfer device <NUM> to be inflated and moved in a longitudinal direction, such that the patient transfer device <NUM> partially extends over an edge of the modality <NUM>. Once extended, the air source may be turned off, the medical procedure or therapy may be performed on the patient, and the air source can be turned on again such the patient transfer surface <NUM> may be moved to a new position. Without the sculpted feature, the air passage would likely pinch off, for example, at location B in <FIG>.

Claim 1:
A patient transfer device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) comprising:
a top surface (<NUM>) of a patient support component configured to support a patient thereon; and
a bottom surface (<NUM>) of the patient support component configured to face a support surface, the bottom surface (<NUM>) being fabricated from a rigid material defining one or more areas having an integrally sculpted concave feature (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) which extends lengthwise or longitudinally along the length (<NUM>) of the patient transfer device (<NUM>) forming an air bearing adjacent to the bottom surface (<NUM>);
wherein passage of air flow below the bottom surface (<NUM>) delivers air to the air bearing, the air bearing being configured to reduce friction between the patient transfer device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) and the support surface when air is delivered to the air bearing, thereby facilitating transport of the patient transfer device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) when supporting the patient on the top surface (<NUM>) of the patient transfer device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>), wherein the air bearing is provided by a bladder (<NUM>, <NUM>, <NUM>), the bladder comprising a top layer (<NUM>) sealed to a bottom layer (<NUM>), the seal at least partially enclosing an interior region.