Patent Publication Number: US-6701554-B2

Title: Imaging stretcher with pivotable armboards, and handles, positioned over wheel assemblies

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a division of U.S. Ser. No. 10/106,075 filed Mar. 26, 2002, now U.S. Pat. No. 6,615,430 which is a division of U.S. Ser. No. 09/507,500 filed Feb. 18, 2000, now U.S. Pat. No. 6,421,854. U.S. Ser. No. 09/507,500 and U.S. Ser. No. 10/106,075 are assigned to the same assignee as this application, and both of which are hereby incorporated by reference herein. 
    
    
     BACKGROUND AND SUMMARY OF THE INVENTION 
     The present invention generally relates to a hospital stretcher. More particularly, the present invention relates to an imaging stretcher which lends itself to fluoroscopy imaging. 
     Fluoroscopy imaging with a C-Arm is used by caregivers for diagnostic and surgical visualization. Many conventional imaging tables have designs based on operating room tables. Often these tables are of a cantilever design where the support surface extends out from a single support column. Such tables usually have all electric controls, are relatively large and heavy, and are also expensive. Typically, a room having an operating room-type table is set up in a medical facility, and a C-Arm is temporarily brought into the room when needed for fluoroscopic observations. 
     Due to increase in the number of outpatient centers and clinics, especially pain management clinics, a need has arisen for a low cost, transportable imaging stretcher. In pain management procedures, the patient is placed on a support surface in a prone position and a nerve-deadening solution is injected from a needle to precise areas of the spine. Fluoroscopy imaging with a C-Arm is used to determine the location of the needle in the patient during such procedures. The C-Arm must be positioned to visualize specific places on the spine which requires the C-Arm to be moved between the neck and the lower back of a patient resting on a support surface, tilted to odd angles, and rotated from a vertical to a horizontal orientation without obstruction from the surface supporting the patient. Caregivers will appreciate a low cost imaging stretcher which includes an unobstructed X-ray window from the tailbone to the head of a patient resting on the support surface, with the ability to angle and maneuver the C-Arm around and under the patient. 
     There are some stretchers on the market today that have a radiolucent top that can be used for C-Arm procedures, but have a relatively wide surface with metal structure down the sides that interfere with rotating the C-Arm and shooting an image horizontally or diagonally through a patient. Some of these stretchers have an upper deck or a litter that slides end to end to achieve a large X-ray window, but they do not slide far enough so that the C-Arm can position under the head of a patient supported on the litter, and shoot an image diagonally through the neck without having to pull the C-Arm out from under the patient. Also in these stretchers, the C-Arm cannot be moved from the head to the lower back without obstruction. Some of these stretchers have a C-shaped base that allows C-Arm access from one side only. 
     An imaging stretcher according to the present invention includes a base having a head end and a foot end, an upper deck formed from a radiolucent material, and actuators coupled to the base adjacent to the head end and the foot end of the base respectively for movably supporting the upper deck. According to one aspect of the invention, the head end and foot end actuators are spaced wide apart to define a central imaging region above the base which is free of any components that would interfere with fluoroscopic imaging of a patient supported on the upper deck. 
     According to another aspect of the invention, the head end and foot end actuators are coupled to the upper deck such that the upper deck is movable toward the foot end of the base. According to a further aspect of the invention, the upper deck may be unlocked, moved to a desired position and locked in place. According to still another aspect of the invention, movement of the upper deck toward the foot end of the base locates the head of a patient supported on the deck between the head end and foot end actuators in the central imaging region. According to a further aspect of the invention, a portion of the base extending between the head end and foot end actuators is formed to be closer to the floor than the end sections thereof supporting the casters to provide more clearance between the upper deck and the base between the actuators in the central imaging region. 
     According to another aspect of the invention, the upper deck is movable between a lowered position and a raised position, and pivotable between a first position where the foot end of the upper deck is raised above the head end thereof (also known as Trendelenberg position) and a second position where the head end of the upper deck is raised above the foot end thereof (also known as reverse Trendelenberg position). 
     According to still further aspect of the invention, the upper deck is formed to include a cutout adjacent to the head end thereof to provide space for a patient&#39;s face lying in a prone position on the upper deck. According to another aspect of the invention, the upper deck is formed to include a pair of openings adjacent to first and second sides thereof for supporting a pair of removable siderails. According to still another aspect of the invention, the upper deck is formed to include a plurality of handles which are also made of radiolucent material. According to a further aspect of the invention, the cutout, the openings for the siderails and the handles are all integrally molded with the upper deck. 
     According to another aspect of the invention, an elongated shaft having a longitudinal axis is coupled to the base for movement along the longitudinal axis. A foot pedal is movably mounted to the base adjacent to the foot end, and is configured to engage a portion of the shaft adjacent to the foot end to move the shaft toward the head end and cause the head end actuator to adjust the elevation of the head end of the upper deck. According to yet another aspect of the invention, the shaft is mounted to the base for rotation about the longitudinal axis between a first orientation and a second orientation. A steering wheel is coupled to the shaft for movement relative to the base between a first position spaced apart from the floor when the shaft is rotated to the first orientation and a second position engaging the floor when the shaft is rotated to the second orientation. 
     Additional features of the present invention will become apparent to those skilled in the art upon a consideration of the following detailed description of the preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The detailed description particularly refers to the accompanying figures in which: 
     FIG. 1 is a side view of an imaging stretcher according to the present invention, showing a relatively narrow upper deck supported above a relatively low profile base by a pair of hydraulic cylinders which are spaced wide apart to form a central imaging region free of any non-radiolucent components, the upper deck being mounted to the base for movement toward the foot end of the stretcher, and further showing in phantom the upper deck in a lowered position, 
     FIG. 2 is a side view similar to FIG. 1, showing the upper deck in a Trendelenberg position where a patient&#39;s feet are raised above the head, 
     FIG. 3 is a side view similar to FIGS. 1 and 2, showing the upper deck in a reverse Trendelenberg position where a patient&#39;s head is raised above the feet, 
     FIG. 4 is a plan view of the stretcher of FIGS. 1-3, showing the upper deck formed to include a push handle near the head end, a pair of downwardly-sloping side handles near the foot end, a cutout near the head end to provide space for a patient&#39;s face lying in a prone position on the upper deck, a pair of armboards pivotally coupled near the head end of the upper deck for supporting a patient&#39;s arms, a pair of openings adjacent to the two sides of the upper deck for removably receiving a pair of siderails, and a cross bar near the head end of the upper deck for supporting one or more IV poles, 
     FIG. 5 is a plan view of the stretcher chassis without the upper deck and without a shroud covering the base, the base including two cross members held in longitudinally spaced apart relationship by two longitudinally-extending, laterally-spaced siderails, a caster assembly coupled to each end of the two cross members, a cross plate attached to the two siderails at each end for supporting head end and foot end hydraulic pump/cylinder assemblies, a steering wheel support assembly movably coupled to the two siderails intermediate of the two cross members, a longitudinally-extending, slidably-mounted brake-steer shaft coupled to the steering wheel support assembly, a brake-steer butterfly pedal pivotally mounted at each end of the two cross members, head end and foot end-pressure release pedals movably coupled to the base near the foot end, a foot pump pedal mounted to the base near the foot end and coupled to hydraulic pumps for pumping fluid into the hydraulic cylinders, 
     FIG. 6 is a perspective view of the foot end of the base, showing the foot end cross member, two longitudinally-extending siderails coupled to the cross member, a caster assembly coupled to one end of the cross member, a brake-steer butterfly pedal coupled to the brake-steer shaft, a pair of hydraulic pressure release pedals coupled to the foot end of the base, a linkage assembly coupling a head end pressure release pedal to the brake-steer shaft, and a foot pump pedal coupled to the base and coupled to the hydraulic pumps, 
     FIG. 7 is a sectional view along the line  7 — 7  in FIG. 5, and showing the steering wheel support assembly movably coupled to the siderails, and disposed in a raised position spaced apart from the floor, 
     FIG. 8 is a sectional view similar to FIG. 7, and showing the steering wheel support assembly in a lowered, floor-engaging position, 
     FIG. 9 is a perspective view showing a support assembly coupling the head end of the upper deck to the head end hydraulic cylinder, the head end support assembly including two generally rectangular frames nested within each other, the rectangular frames being pivotally coupled to each other near their respective foot ends by a pair of pivot pins for rotation about a transversely-extending axis, and showing two longitudinally-extending, laterally-spaced guide grooves formed on the underside of the upper deck near the head end adjacent to the two sides of the upper deck for receiving rim portions of a pair of wheels rotatably mounted on said pivot pins, and further showing a pair of rollers mounted to the underside of the upper deck near the head end adjacent to the two sides of the upper deck by a pair of downwardly-projecting brackets for reception in a pair of outwardly-opening channels formed in the outer rectangular frame, 
     FIG. 10 is a sectional view taken along the line  10 — 10  in FIG. 9 of the head end of the upper deck, and showing the two generally rectangular nested frames, a roller coupled to the underside of the upper deck and received in an outwardly-opening channel formed in the outer rectangular frame, the head end hydraulic cylinder coupled to a cross member of the inner rectangular frame by a nut and bolt assembly, 
     FIG. 11 is a sectional view of a foot end of the upper deck taken along the line  11 — 11  in FIG. 4, a side handle with a portion broken away, a foot end cross member coupled to the foot end hydraulic cylinder by a nut and bolt assembly, an upwardly-projecting bracket pivotally coupled to one end of the foot end cross member and supporting a pair of rollers, the rollers being configured for reception in an inwardly-opening siderail coupled to the underside of the upper deck near the foot end adjacent to one side thereof for supporting longitudinal movement of the upper deck within a given range, a longitudinally-extending locking rod attached to the underside of the upper deck near the foot end adjacent to said one side, a clamp supported by the foot end cross member and disposed about the locking rod, the clamp normally securely gripping the locking rod to lock the sliding upper deck at a given longitudinal position, a release bar pivotally mounted to the upper deck and coupled to the clamp for freeing the upper deck when actuated to enable the caregiver to adjust the longitudinal position of the upper deck, 
     FIG. 12 is a sectional view of the foot end of the upper deck taken along the line  12 — 12  in FIG. 11, showing the side handle with portions broken away, two rollers in phantom received in the inwardly-opening siderail coupled to the underside of the upper deck near the foot end adjacent to said one side, an upwardly-projecting bracket pivotally coupled to the foot end cross member for supporting the rollers near the foot end of the upper deck, the locking rod fixed to the underside of the upper deck, the clamp disposed about the locking rod, and a cable coupling the release bar to the clamp, 
     FIG. 13 is a side view similar to FIG. 1, showing in dotted lines the upper deck slid toward the foot end of the stretcher, and further showing in solid lines the C-Arm positioned adjacent to the head of a patient supported on the upper deck and tilted about a transversely-extending axis to shoot an image diagonally through the neck, and further showing in phantom lines the C-Arm positioned adjacent to the lower back of the patient and tilted to shoot an image diagonally through the tailbone, 
     FIG. 14 is an end view of the stretcher, showing the C-Arm rotated about a longitudinally-extending axis to shoot an image through the head of a patient supported on the upper deck without interference from siderails or any other metal structures in the imaging region, and 
     FIG. 15 is a plan view similar to FIG. 4, showing the upper deck formed to include a cutout near the head end to provide space for a patient&#39;s face lying in a prone position on the upper deck. 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Although the term “stretcher” is used throughout the specification, it is understood that the novel features of the invention may be incorporated into any type of a patient support device—such as a hospital bed or an operating table. Also, although the term “fluoroscopy” is used throughout the specification for convenience, it will be construed to include any other type of imaging. Also the terms “hydraulic pump” or “hydraulic cylinder” or “hydraulic pump/cylinder assembly” will be construed to include any hydraulic, pneumatic, mechanical or electrical device for lifting, lowering or tilting the upper deck. In other words, the features of the present invention are not to be limited to the use with a stretcher or a fluoroscope or a hydraulic device. 
     Referring to FIGS. 1-4, a stretcher  20  in accordance with the present invention includes a low profile base  22  with a relatively large wheelbase, a relatively narrow slidably-mounted upper deck  24  coupled to the base  22 , a protective shroud  26  covering the base  22 , a head end  32 , a foot end  34 , an elongated first side  36 , an elongated second side  38  and a longitudinal axis  40 . As used in this description, the phrase “head end 32” will be used to denote the end of any referred-to object that is positioned to lie nearest the head end  32  of the stretcher  20 , and the phrase “foot end 34” will be used to denote the end of any referred-to object that is positioned to lie nearest the foot end  34  of the stretcher  20 . Likewise, the phrase “first side 36” will be used to denote the side of any referred-to object that is positioned to lie nearest the first side  36  of the stretcher  20  and the phrase “second side 38” will be used to denote the side of any referred-to object that is positioned to lie nearest the second side  38  of the stretcher  20 . 
     The upper deck  24  is formed from a radiolucent material—end to end and side to side—to facilitate fluoroscopic observations of a patient supported on the upper deck  24 —for example, for conducting pain management procedures. The stretcher  20  is particularly suitable for use in endoscopy, cardiac catheterization, and other procedures requiring fluoroscopy. As shown in FIG. 13, the deck  24  is movable toward the foot end  34  of the stretcher  20  so that a C-Arm  42  can position under the head of a patient supported on the upper deck  24  and tilted about a transversely-extending axis to shoot an image diagonally through the neck of the patient without pulling the C-Arm out from under the patient. Relatively narrow upper deck  24  (about 20 inches or 50 centimeters wide) allows the C-Arm  42  to rotate about a longitudinally-extending axis from a vertical orientation to a horizontal orientation, as shown in FIG. 14, to shoot an image horizontally through the head of a patient supported on the upper deck  24  without interference from siderails—particularly non-removable metal siderails. 
     The base  22  is supported on floor  28  by four caster assembles  30  to allow the stretcher  20  to be rolled over the floor  28  to transport a patient. The upper deck  24  is movably supported above the base  22  by a lifting mechanism  50  in order to raise, lower, and tilt the upper deck  24  relative to the base  22 . Illustratively, the upper deck lifting mechanism  50  includes head end and foot end hydraulic cylinders  52  and  54  covered by flexible boots  56 . The hydraulic cylinders  52 ,  54  (sometimes referred to herein as the actuators) are spaced wide apart (about 60 inches or 150 centimeters) to provide room for maneuvering the C-Arm  42 . The hydraulic cylinders  52 ,  54  are coupled to respective hydraulic pumps  62  and  64  supported on the base  22 . The head end hydraulic cylinder  52  controls the vertical position of the head end  32  of the upper deck  24  relative to the base  22 , and the foot end hydraulic cylinder  54  controls the vertical position of the foot end  34  of the upper deck  24  relative to the base  22 . The hydraulic cylinders  52 ,  54  adjust the vertical position of the upper deck  24  between a low position (about 24 inches or 60 centimeters above the floor) to facilitate patient egress and ingress, and a high position (about 40 inches or 102 centimeters above the floor) to provide a comfortable position for a Surgeon standing next to a patient supported on the upper deck  24 . In addition, the hydraulic cylinders  50 ,  52  tilt the upper deck  24  to one of three positions—a flat, horizontal position shown in FIG. 1, a Trendelenburg position shown in FIG. 2 where a patient&#39;s feet are raised above the patient&#39;s head, or a reverse Trendelenburg position shown in FIG. 3 where the patient&#39;s head is raised above the patient&#39;s feet. 
     A mattress pad  70  may be disposed on the upper deck  24  for supporting a patient as shown in FIGS. 1 and 14. The mattress pad  70  may include selectively activated, inflatable bladders to provide special support that may be required for certain medical procedures—such as imaging a patient&#39;s spine when the patient is lying in a prone position on the deck  24 , for example, for pain management procedures. The upper deck  24  is configured to form a raised, gently-curved push handle  72  near the head end  32  of the stretcher  20 , and two downwardly-sloping side handles  74  near the foot end  34  adjacent to the two sides  34 ,  36  of the stretcher  20  as shown in FIGS. 1-4. A caregiver can grip either the head end push handle  72  or the two foot end side handles  74  to maneuver the stretcher  20  over the floor  20 . After unlocking the upper deck  24 , the caregiver may use the head end push handle  72  or the foot end side handles  74  to move the upper deck  24  to a desired position, and then lock the upper deck  24  in place. As indicated, the caregiver may wish to move the upper deck  24  to a different position to view a different portion of a patient&#39;s body for a diagnostic or a surgical procedure. The ergonomic designs of the handles  72 ,  74  provide a comfortable grip. 
     As shown in FIGS. 4 and 15, a cutout  76  is formed in the upper deck  24  to provide space for a patient&#39;s face lying in a prone position on the upper deck  24 . In accordance with one aspect of the present invention, the stretcher  20  is configured such that the cutout  76  is located between the hydraulic cylinders  52 ,  54  in an X-ray window  300  when the deck  24  is moved toward the foot end  34  of the stretcher  20  to facilitate shooting an image diagonally through the neck of the patient as shown in FIG. 13. A transversely-extending cross bar  84  is secured to the upper deck  24  near the head end  32  of the stretcher  20 . In accordance with another aspect of the present invention, an armboard  78  is pivotally coupled to each end of the cross bar  84  by a pivot pin  78 ′ adjacent to the two sides  34 ,  36  for movement between a first position extending toward the foot end and a second position extending away from the foot end for supporting a patient&#39;s arms. Pivoting armboards  78  allow prone patients to position their arms over their heads and still be supported by the armboards  78  as shown in FIG.  4 . The upper deck  24  is further configured to form openings  80  adjacent to the two sides  34 ,  36  for removably receiving a pair of plug-in siderails  82  as shown in FIG.  1 . The removable siderails  82  allow shooting an image diagonally through the head or the tailbone of a patient supported on the upper deck  24  without interference from the siderails  82  as shown in FIG.  14 . One or more IV poles may be secured to the cross bar  84  near the head end  32  of the stretcher  20  for holding solution containers or other objects at a position elevated above the upper deck  24 . The foot end portion  88  of the upper deck  24  may be angled away from the upper deck  24  to provide comfortable ankle support for a patient lying in a prone position on the upper deck  24 . Illustratively, the upper deck  24  is molded from a radiolucent foam plastic material and provided with fiber glass outer shell. The handles  72 ,  74 , the cutout  76  and the siderail openings  80  may all be integrally molded with the upper deck  24 . 
     The combination of a relatively narrow deck (about 20 inches or 50 centimeters), a high position of the deck  24  when raised to a full height (about 40 inches or 102 centimeters above the floor) and widely spaced-apart hydraulic cylinders  52 ,  54  (about 60 inches or 150 centimeters) can cause instability. Stability is very important during these types of procedures, and the litter  24  must not wobble. Also, the litter  24  must be stable for a patient to get on and off. Typically, OR tables (Operating Room tables) have a very heavy base to add stability. A heavy base is not acceptable on fluoroscopic-type stretchers that have some intention of being transportable. A wide wheelbase (about 24 inches or 60 centimeters) is therefore desired for stability along with a narrow top (about 20 inches or 50 centimeters) to allow rotation of the C-arm  42  about a longitudinally-extending axis as shown in FIG.  14 . However, the caster assemblies  30  or the brake-steer pedals  114  cannot protrude farther out than the upper deck  24  as it creates a trip hazard if walking around the stretcher  20 . In accordance with an aspect of the present invention, the side handles  74  and the armboards  78  extend outwardly from the deck  24  beyond the caster assemblies  30  and the brake-steer pedals  114  coupled to the base  22 . Thus, the caster assemblies  30  and the brake-steer pedals  114  remain within the footprint of the upper deck  24 , the side handles  74  and the armboards  78 . 
     As shown in FIG. 5, the base  22  includes a head end cross member  92  and a foot end cross member  94 . The head end and foot end cross members  92 ,  94  are held in longitudinally spaced apart relationship by two longitudinally-extending, laterally-spaced siderails  96  and  98  secured to downwardly-extending brackets (not shown) fixed to the cross members  92 ,  94 . The two longitudinally-extending siderails  96 ,  98  have step-down middle portions  100  that are configured to be closer to the floor  28  (about 4 inches or 10 centimeters from the floor  28 ) than their respective end portions (about 13 inches or 33 centimeters from the floor  28 ). The step-down middle portions  100  of the base  22  provides more vertical clearance between the base  22  and the upper deck  24  between the two hydraulic cylinders  52 ,  54  in the central imaging region  300  for the C-Arm  42 . High end portions of the base  22 , on the other hand, allow use of larger caster assemblies  30 . A short end section  102  is attached at each end of the two siderails  96 ,  98  to lend rigidity to the structure. Coupled to each end of the two cross members  92 ,  94  is an outwardly-extending right angle bracket  104 . Each right angle bracket  104  supports a caster assembly  30  and a brake-steer butterfly pedal  114 . A cross plate  106  is attached to the two siderails  96 ,  98  near the head end  32  of the base  22  to support the head end hydraulic cylinder/pump assembly  52 / 62 . Likewise, another cross plate  106  is attached to the two siderails  96 ,  98  near the foot end  32  of the base  22  to support the foot end hydraulic cylinder/pump assembly  54 / 64 . The cross members  92 ,  94 , the siderails  96 ,  98  and short end sections  102  are in the form of extruded tubes having a square cross section, and made from rigid high strength, light weight materials—such as steel or aluminum. 
     A longitudinally-extending brake-steer shaft  108  is slidably and rotatably mounted to the siderail  98  near the second side  38  of the base  22  by a plurality of brackets  110  as shown in FIG.  5 . The brake-steer shaft  108  rotates about its longitudinal axis  112  in either direction in response to rotation of a brake-steer butterfly pedal  114 , and is translatable in a longitudinal direction, indicated by a double-headed arrow  116 , either toward or away from the foot end  34  in response to the operation of a head end pressure release pedal  182  coupled to the foot end  34  of the base  22 . A linkage assembly  122  couples the brake-steer shaft  108  to two brake-steer pedals  114  at the head end  32  of the stretcher  20 . Likewise, a linkage assembly  124  couples the brake-steer shaft  108  to two brake-steer pedals  114  at the foot end  34  of the stretcher  20 . Since the two linkage assemblies  122 ,  124  are similar to each other, only the foot end linkage assembly  124  will be described. 
     Referring to FIG. 6, the foot end linkage assembly  124  includes a cross shaft  126  having its ends rotatably supported by two outwardly-extending right angle brackets  104  coupled to the foot end cross member  94 . Another bracket  128 , having a C-configuration in plan view, supports the cross shaft  126  intermediate of the two right angle brackets  104 . The bracket  128  includes two vertically-disposed side plates  128 ′ held in laterally spaced apart relation by a crosswise back plate  128 ″. The back plate  128 ′ is fixed to the foot end cross member  94 . A brake-steer pedal  114  is fixed to each end of the cross shaft  126 . A bent link  130  has a first end  130 ′ fixed to the cross shaft  126  between the two vertically-extending side plates  128 ′ of the bracket  128 , and a second end  130 ″ pivotally coupled to a first end  132 ′ of a connecting link  132 . The second end  132 ″ of the connecting link  132  is pivotally coupled to a first end  134 ′ of a short link  134 . A second end  134 ″ of the short link  134  is fixed to the foot end  34  of the brake-steer shaft  108 . 
     The brake-steer pedal  114  has three positions—(a) a generally horizontal neutral position, (aa) a braking position where a braking portion  136  of the brake-steer pedal  114  is angled downwardly and an opposite steering portion  138  of the brake-steer pedal  114  is angled upwardly, and (aaa) a steering position where the steering portion  138  of the brake-steer pedal  114  is angled downwardly and the braking portion  136  of the brake-steer pedal  114  is angled upwardly. When the brake-steer pedal  114  is generally horizontal, the caster assemblies  30  are free to swivel and rotate. From the generally horizontal neutral position, the caregiver can depress the braking portion  136  of the brake-steer pedal  114  in an anticlockwise braking direction indicated by arrow  140  in FIG. 6 to a braking position. Rotation of the brake-steer pedal  114  to the braking position moves brake shoes (not shown) into engagement with the caster assemblies  30  to lock the caster assemblies  30  in place. 
     From the braking position, the caregiver can depress the steering portion  138  of the brake-steer pedal  114  to rotate the brake-steer pedal  114  back to the horizontal neutral position. When the brake-steer pedal  114  is in the neutral position, the caregiver can depress the steering portion  138  of the brake-steer pedal  114  to rotate the cross shaft  126  in a clockwise steering direction indicated by arrow  142  in FIG. 6 to a steering position. Rotation of the cross shaft  126  to the steering position, causes the bent link  130  to also rotate in the clockwise direction  142  to, in turn, cause the connecting link  132  to move in a downwardly direction indicated by arrow  144  and cause the short link  134  and the brake-steer shaft  108  to rotate in an anticlockwise direction indicated by arrow  146  in FIG.  6 . Rotation of the brake-steer shaft  108  in the anticlockwise direction  146  causes a steering wheel support assembly  150  to lower a pair of steering wheels  152  to engage the floor  28 . 
     As shown in FIGS. 5,  7  and  8 , the steering wheel support assembly  150  includes a shaft  154  having the wheels  152  (also referred to herein as center or steering wheels) mounted side-by-side thereon. The shaft  154  is fixed to the foot end  34  of an elongated wheel-mounting bracket  156 . The head end  32  of the wheel-mounting bracket  156  is pivotally coupled to a cross plate  158  having its ends attached to the siderails  96 ,  98 . The wheel-mounting bracket  156  is movable between a raised position shown in FIG. 7 where the steering wheels  152  are spaced apart from the floor  28 , and a lowered position shown in FIG. 8 where the steering wheels  152  are in engagement with the floor  28 . A vertically-extending spring  160  extends between the foot end  34  of the wheel-mounting bracket  156  and the siderail  96 . The vertically-extending spring  160  normally biases the wheel-mounting bracket  156  to the raised position spaced apart from the floor  28 . Fixed to the wheel-mounting bracket  156  is a transversely-extending cam plate  162  having a downwardly sloping end portion  164  extending toward the brake-steer shaft  108 . The downwardly sloping end portion  164  of the cam plate  162  is configured for engagement with a cam  166  mounted on the brake-steer shaft  108 . As explained above, rotation of the steer portion  138  of the brake-steer pedal  114  in the clockwise direction  142  to the steering position causes the brake-steer shaft  108  to rotate in the anticlockwise direction  146  shown in FIG.  6 . Rotation of the brake-steer shaft  108  in the anticlockwise direction  146  causes the cam  166  fixed thereto to also rotate in an anticlockwise direction indicated by arrow  168  in FIG.  7 . Rotation of the cam  164  to in the anticlockwise direction  168  displaces the wheel-mounting bracket  156  in a downward direction indicated by arrow  170 , causing the steering wheels  152  to engage the floor  28  as shown in FIG.  8 . 
     The upper deck lifting mechanism  50  includes a foot pump pedal  180 , a head end pressure release pedal  182  and a foot end pressure release pedal  184  as shown in FIG.  6 . The pedals  180 - 184  are pivotally coupled to the base  22  near the foot end  34  of the stretcher  20 , and control the vertical movement of the head end  32  and the foot end  34  of the upper deck  24 . From their generally horizontal operative positions shown in FIG. 6, the pressure release pedals  182 ,  184  can be flipped up to their respective, generally vertical out-of-the-way inoperative positions. 
     Referring to FIGS. 1-3,  5  and  6 , an actuating member  186  includes an outwardly-extending, generally horizontal portion  188 , an intermediate base portion  190  and a downwardly-extending, generally vertical portion  192 . The foot pump pedal  180  is fixed to the free end of the generally horizontal, outwardly-extending portion  188 . As shown in FIG. 5, the base portion  190  of the actuating member  186  is attached to a cross shaft  194  rotatably coupled to the siderails  96 ,  98  near the foot end  34  of the stretcher  20 . As shown in FIGS. 1-3, the free end of the generally vertical portion  192  of the actuating member  186  is coupled to the foot end  34  of a longitudinally-extending, reciprocally-mounted shaft  198  through a right angle member  196  such that vertical reciprocating motion of the foot pump pedal  180  causes horizontal reciprocating motion of the shaft  198 . The longitudinally-extending shaft  198  is slidably mounted to the siderail  96  near the first side  36  of the stretcher  20  (on the side opposite from the longitudinally-extending brake-steer shaft  108 ) by a plurality of brackets  200  for movement toward and away from the foot end  34  of the stretcher  20  in a direction indicated by a double-headed arrow  202  in FIG.  5 . The longitudinally-extending shaft  198  is coupled to the head end hydraulic pump  62  near the head end  32  of the stretcher  20  (FIGS.  1 - 3 ), and to the foot end hydraulic pump  64  near the foot end  34  of the stretcher  20 . As shown in FIGS. 1-3 and  6 , a generally horizontally-extending spring  204  is coupled between the free end of the generally vertical portion  192  and the foot end  34  of the siderail  96  to bias the foot pump pedal  180  upwardly to a generally-horizontal raised position shown in FIG.  6 . From the generally-horizontal raised position, the caregiver can depress the foot pump pedal  180  to cause the longitudinally-extending shaft  198  to move toward the foot end  34  of the stretcher  20 . Caregiver can then release the pressure on the foot pump pedal  180  to allow the generally horizontally-extending spring  204  to pull the longitudinally-extending shaft  198  away from the foot end  34  of the stretcher  20 , and to lift the foot pump pedal  180  upwardly to the generally-horizontal raised position shown in FIG.  6 . Caregiver can then again depress the foot pump pedal  180 . Reciprocating motion of the shaft  198  causes the pumps  62 ,  64  to pump fluid into the hydraulic cylinders  52 ,  54  respectively to, in turn, cause the upper deck  24  to rise. 
     As shown in FIG. 6, an actuating member  210  includes an outwardly-extending, generally horizontal portion  212 , an intermediate base portion  214  and a downwardly-extending, generally vertical portion  216 . The head end pressure release pedal  182  is coupled to the free end of the generally horizontal portion  212 . The base portion  214  of the actuating member  210  is pivotally coupled to a c-shaped bracket  218  mounted to the foot end  34  of the siderail  98  near the second side  38  of the stretcher  20 . The free end of the downwardly-extending portion  216  is configured to engage a transverse plate  220  fixed on the brake-steer shaft  108  near the foot end  34  thereof. From a generally horizontal position shown in FIG. 6, the caregiver can depress the head end pressure release pedal  182  to thereby cause the downwardly-extending portion  216  of the actuating member  210  to rotate in a clockwise direction indicated by arrow  222 . Rotation of the generally vertical portion  216  in the clockwise direction  222  pushes the transverse plate  220  and the brake-steer shaft  108  coupled thereto toward the head end  32  of the stretcher  20 . When the brake-steer shaft  108  moves toward the head end  32 , a transversely-mounted actuator  224  coupled to the brake-steer shaft  108  depresses a pressure release pin or button  226  coupled to the head end hydraulic pump  62  as shown in FIG. 5 to release the pressure in the head end hydraulic cylinder  52  to, in turn, lower the head end  32  of the upper deck  24 . As shown in FIG. 5, a generally horizontally-extending spring  228  coupled between the brake-steer shaft  108  and the siderail  98  biases the brake-steer shaft  108  to return to its original position when the pressure release pedal  182  is freed. 
     An actuating member  240  includes an outwardly-extending, generally horizontal portion  242 , an intermediate base portion  244  and a downwardly-extending, generally vertical portion  246 . The foot end pressure release pedal  184  is coupled to the free end of the generally horizontal portion  242 . The base portion  244  of the actuating member  240  is pivotally coupled to a c-shaped bracket  248  mounted to the foot end  34  of the siderail  98  near the second side  38  of the stretcher  20 . When the foot end pressure release pedal  184  is depressed, the free end of the downwardly-extending portion  246  depresses a pressure release pin or button coupled to the foot end hydraulic pump  64  to release the pressure in the foot end hydraulic cylinder  54  to, in turn, lower the foot end  34  of the upper deck  24 . 
     Referring to FIGS. 9-12, the head end  32  of the radiolucent upper deck  24  is coupled to the head end hydraulic cylinder  52  by a head end support assembly  302 , and the foot end  34  of the deck  24  is coupled to the foot end hydraulic cylinder  54  by a foot end support assembly  304 . As previously explained, the head end cylinder  52  controls a vertical position of the head end  32  of the upper deck  24 , and the foot end cylinder  54  controls a vertical position of the foot end  34  of the upper deck  24 . As shown in FIGS. 1-3, the head end and foot end support assemblies  302 ,  304  are spaced wide apart (about 60 inches or 150 centimeters) to define the central imaging region  300  above the base  22  between the head end and foot end hydraulic cylinders  52 ,  54  which is free of any metallic structures that would interfere with imaging. The two support assemblies  302 ,  304  (sometimes referred to herein as the head end and foot end connectors) secure the upper deck  24  to the base  22 , while allowing translation of the upper deck  24  toward the foot end  34  of the stretcher  20  so that a C-Arm  42  can be positioned anyplace from the neck to the tailbone of a patient supported on the deck  24  or tilted to a suitable angle as shown in FIG. 13, or rotated from a vertical to a horizontal orientation as shown in FIG. 14 without any obstruction and without having to pull the C-Arm out from under the patient. For example, The C-Arm  42  can be located near the head end  32  of the stretcher  20  and tilted as shown in FIG. 13 to shoot an image diagonally through the neck of the patient. 
     As shown in FIGS. 9 and 10, the head end support assembly  302  includes a generally rectangular inner frame  312  nested inside a generally rectangular outer frame  314 . The inner and outer frames  312 ,  314  are pivotally coupled to each other near their respective foot ends  34  for rotation about a first transversely-extending axis  316 . The inner frame  312  includes first and second longitudinally-extending siderails  322 ,  324  in the form of inwardly-opening channels. The longitudinally-extending siderails  322 ,  324  are held in laterally spaced apart relationship by a head end cross member  332  in the form of a circular tube and a foot end cross member  334  in the form of a square tube. The head end cross member  332  is rigidly attached to the head end hydraulic cylinder  52  by a nut and bolt assembly  336 . The outer frame  314 , on the other hand, includes first and second longitudinally-extending siderails  342 ,  344  in the form of outwardly-opening channels. The longitudinally-extending siderails  342  and  344  are held in laterally spaced apart relationship by a head end cross member  352  in the form of a square tube and a foot end cross member  354  in the form of a rectangular plate mounted on the top side of the outer frame  314 . The foot ends  34  of the inner siderails  322 ,  324  and the foot ends  34  of the outer siderails  342 ,  344  are pivotally coupled to each other by pivot pins  358  for rotation about the transversely-extending axis  316 . Pivotal coupling of the inner and outer frames  312 ,  314  allows the upper deck  24  to pivot to a Trendelenburg position shown in FIG. 2 or to a reverse Trendelenburg position shown in FIG.  3 . 
     The underside of the upper deck  24  is formed to include two longitudinally-extending, laterally-spaced guide grooves  362  for receiving rim portions of wheels  372  freely rotatable on the pivot pins  358 . The wheels  372  are located between the outer walls of the inner siderails  322 ,  324  and the inner walls of the outer siderails  342 ,  344  adjacent to the foot ends  34  of the inner and outer frames  312 ,  314 . The outwardly-opening channels  342 ,  344  of the outer frame  314  are configured to receive a pair of rollers  382  mounted to the underside of the upper deck  24  for rotation about a second transversely-extending axis  386  by a pair of downwardly-projecting brackets  392 . As shown in FIG. 10, a pair of guard members  402  in the form of inwardly-opening channels are coupled to the outwardly-opening channels  342 ,  344  by plate members  412  mounted on the bottom side thereof to form enclosed tracks  416  for receiving the rollers  382  mounted to the underside of the upper deck  24 . The outwardly-facing top edges  418  of the outer channel members  342 ,  344  and the inwardly-facing top edges  420  of the guard members  402  form longitudinally-extending channels or slots  422  along the two sides of the upper deck  24  for slidably receiving the roller-supporting brackets  392 . The reception of the rollers  382  mounted to the underside of the upper deck  24  in the enclosed tracks  416  secures the head end  32  of the upper deck  24  to the base  22 , while allowing the upper deck  24  to translate longitudinally relative to the base  22  within a certain limited range. 
     Referring to FIGS. 11 and 12, the foot end support assembly  304  includes a cross member  424  in the form of a circular tube rigidly attached to the foot end hydraulic cylinder  54  by a nut and bolt assembly  426 . An upwardly-projecting bracket  432  is pivotally attached to the each end of the tubular cross member  424  for rotation about a third transversely-extending axis  436 . Pivotal movement of the brackets  432  relative to the foot end cross member  424  allows the upper deck  24  to pivot to a Trendelenburg position shown in FIG. 2 or to a reverse Trendelenburg position shown in FIG.  3 . Each of the brackets  432  supports a pair of rollers  442  configured for reception in the first and second longitudinally-extending, inwardly-opening channels  452  mounted to the underside of the upper deck  24  adjacent to the foot end  34  thereof. Reception of the rollers  442  mounted to the cross member  424  in the inwardly opening channels  452  mounted to the underside of the upper deck  24  holds the foot end  34  of the upper deck  24  in place, while allowing the upper deck  24  to translate longitudinally within a predetermined range relative to the base  22 . 
     When the upper deck  24  is horizontal as shown in FIG. 1, a patient&#39;s weight is transferred to the rollers  382  near the head end  32  of the stretcher  20 , and to the rollers  442  near the foot end  34  of the stretcher  20 . The patient&#39;s weight on the rollers  382  near the head end  32  of the stretcher  20  is transferred to the outer siderails  342 ,  344  (urging the outer siderails  342 ,  344  to rotate about the transversely-extending axis  316  in a clockwise direction  456  shown in FIG.  9 ), then to the inner frame  312  through the top cross plate  354 , and finally to the head end hydraulic cylinder  52  through the head end cross member  332 . On the other hand, the patient&#39;s weight on the rollers  442  near the foot end  34  of the stretcher  20  is transferred to the foot end cross member  424  through the pivotally-mounted brackets  432 , and then to the foot end hydraulic cylinder  54  through the foot end cross member  424 . 
     To move the upper deck  24  to the Trendelenburg position shown in FIG. 2 from the horizontal position shown in FIG. 1, hydraulic pressure in the head end hydraulic cylinder  52  is released by using the head end pressure release pedal  182  coupled to the foot end  34  of the stretcher  20 , causing the head end cross member  332  to move down. When the head end cross member  332  moves down, both the inner and outer frames  312  and  314  move down, and the upper deck  24  pivots about the axis  386  of the rollers  382  near the head end  32  of the stretcher  20  and the axis  436  of the pivotally-mounted brackets  432  near the foot end  34  of the stretcher  20 . In the Trendlenburg position, a patient&#39;s weight is transferred to the rollers  382  near the head end  32  of the stretcher  20 , and to the rollers  442  near the foot end  34  of the stretcher  20 . The patient&#39;s weight on the rollers  382  near the head end  32  of the stretcher  20  is transferred to the outer siderails  342  (urging the outer siderails  342 ,  344  to rotate about the transversely-extending axis  316  in a clockwise direction  458  in FIG.  2 ), then to the inner frame  312  through the top cross plate  354 , and finally to the head end hydraulic cylinder  52  through the head end cross member  332 . On the other hand, the patient&#39;s weight on the rollers  442  near the foot end  34  of the stretcher  20  is transferred to the foot end cross member  424  through the pivotally-mounted brackets  432 , and to the foot end hydraulic cylinder  54  through the foot end cross member  424 . 
     To move the upper deck  24  to the reverse Trendelenburg position shown in FIG. 3 from the horizontal position shown in FIG. 1, hydraulic pressure in the foot end hydraulic cylinder  54  is released by using the foot end pressure release pedal  184  coupled to the foot end  34  of the stretcher  20  to cause the foot end cross member  424  to move down. When the foot end cross member  422  moves down, the outer frame  314  pivots about the axis  316  of the wheels  372  near the head end  32  of the stretcher  20  in the direction  460  in FIG.  3 . The upper deck  24 , on the other hand, pivots about the axis  316  of the wheels  72  near the head end  32  of the stretcher  20 , and about the axis  436  of the pivotally-mounted brackets  432  near the foot end  34  of the stretcher  20 . In the reverse Trendlenburg position, a patient&#39;s weight is transferred to the wheels  372  near the head end  32  of the stretcher  20 , and to the rollers  442  near the foot end  34  of the stretcher  20 . The patient&#39;s weight on the wheels  372  near the head end  32  of the stretcher  20  is transferred to the inner frame  312  through the pivot pins  358 , and then to the head end hydraulic cylinder  52  through the head end cross member  332 . On the other hand, the patient&#39;s weight on the rollers  442  near the foot end  34  of the stretcher  20  is transferred to the foot end cross member  424  through the pivotally-mounted brackets  432 , and then to the foot end hydraulic cylinder  54  through the foot end cross member  424 . 
     Thus, the novel configuration of the head end and foot end support assemblies  302  and  304  allows the upper deck  24  to move toward the foot end  34  of the stretcher  20 , so that a C-Arm  42  can be positioned anyplace from the neck to the tailbone of a patient supported on the deck  24 , or tilted about a tranversely-extending axis as shown in FIG. 13, or rotated about a longitudinally-extending axis as shown in FIG. 14 without any obstruction and without the necessity of pulling the C-Arm out from under the patient. The support assemblies  302 ,  304  also allow the entire upper deck  24  to be raised or lowered as shown in FIG. 1, move the upper deck  24  to a Trendelenburg position as shown in FIG. 2 or to a reverse Trendelenburg position as shown in FIG.  3 . 
     An upper deck locking mechanism  470  is provided for selectively locking the upper deck  24  at a given longitudinal position with respect to the base  22  as shown in FIGS. 11 and 12. The upper deck locking mechanism  470  includes a longitudinally-extending locking rod  472  attached to the underside of the foot end  34  of the upper deck  24  near the first side  36  of the stretcher  20  by means of a pair of downwardly projecting brackets  474 . A clamp  476  is disposed about the rod  472 , and is secured to the foot end cross member  424  by a bracket  478 . The clamp  476  is normally biased to tightly grip the rod  472  to lock the upper deck  24  in place. A upper deck release bar  480  is pivotally mounted to the siderail  452  adjacent to the foot end side handle  64  near the first side  36  of the stretcher  20 . The release bar  480  is normally biased in a direction away from the side handle  64 . A cable  482  has one end  484  secured to the release bar  480  and a second end  486  secured to the clamp  476 . To free the upper deck  60 , the release bar  480  is lifted toward the side handle  64 . When the release bar  480  is lifted, the end  484  of the cable  482  attached to the release bar  480  is pulled. When the end  484  of the cable  482  is pulled, the second end  486  of the cable  482  secured to the clamp  476  pulls on the clamp  476  to open it up to release the locking rod  472  to, in turn, free the upper deck  24  to move longitudinally relative to the base  22 . 
     Although the invention has been described in detail with reference to a certain preferred embodiment, variations and modifications exist within the scope and spirit of the invention as described and as defined in the following claims.