Patient Rotator And Method Of Conducting X-ray Studies

Abstract

A patient rotator mounted on an X-ray table and adapted to maintain a center of interest within the patient aligned with an X-ray beam axis as the patient is rotated. The elevation of the patient is automatically adjusted as a function of the angle of rotation in order to provide a relatively constant minimal patient to film distance.

Description

CROSS REFERENCES TO RELATED PATENT AND APPLICATION TILTABLE X-RAY TABLE COMPRISING MEANS TO PRODUCE A VARIABLE SPEED TRANSLATIONAL MOVEMENT, U.S. Pat. No. 3,131,301 issued Apr. 28, 1964 to D. M. Barrett et al.

METHOD AND APPARATUS FOR IMMOBILIZING A PATIENT, Ser. No. 111,602 filed Feb. 1, 1971 by Waldo H. Kliever.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to an apparatus for positioning a patient in a plurality of positions during radiographic studies and the like. More particularly, the invention relates to a patient rotator designed to maintain the center of interest within the patient aligned with the X-ray beam axis during rotation of the patient.

2. Prior Art

A variety of medical diagnostic and therapeutic procedures require repeated repositioning of a patient. Where X-ray diagnostic studies are being made, for instance, it is often desirable to view the same center of interest within the patient from several different angles. It is also often desirable to shift the patient's position so that his organs will reposition relatively.

Patient supporting X-ray tables of a variety of configurations have been proposed to facilitate movement of a patient. These configurations include tables equipped with devices known as patient rotators which rotate the patient about a fixed axis.

Several problems have arisen in conjunction with the operation of most patient rotators due to the fixed nature of their axes of rotation. For instance, where the center of interest to be studied within the patient does not lie along the axis of rotation, rotation of the patient will cause the center of interest to move out of the diagnostic X-ray beam. Thus, before the study can resume, the center of interest must be found and realigned with the beam.

Another problem related to the fixed-axis nature of most patient rotators is their failure to compensate for variations in the patient-to-film distance. It is important to keep the patient in close proximity to the film not only because shorter patient-to-film distances tend to result in better quality radiographs, but more importantly to minimize the patient's radiation dosage. The farther the patient is from the film, the closer he is to the radiation source and the higher his radiation dosage.

Since most patients are thinner front-to-back than they are wide side-to-side, the fixed axis rotator causes the patient to be suspended at a greater height above the film when he is lying on his back than when he is held on one side.

SUMMARY OF THE INVENTION

The present invention overcomes the foregoing drawbacks of the prior art and provides a novel and improved patient rotator, which is selectively adjustable to maintain a center of interest within the patient in alignment with the X-ray beam, during rotation while automatically adjusting the height of the patient above the table during rotation so as to maintain a minimum patient-to-film distance.

A patient supporting platform is rotatably suspended between a pair of end structures for rotation about a longitudinal axis. The end structures house mechanisms for laterally moving the platform from side to side and for elevating and lowering the platform during rotation. A guide track is provided in the form of a slotted end plate having a slot positioned in a plane including the X-ray beam axis. A guide pin extends into the slot for translation there-along. An adjustable positioning mechanism connects the guide pin and the platform such that as the platform is rotated it is caused to be moved laterally. By aligning the guide pin with the center of interest to be studied, the movement of the center of interest is confined to translation along the X-ray beam axis during platform rotation.

An electro-mechanical control system is provided to automatically selectively elevate and lower the platform during rotation. The system includes an arrangement of manually operated and cam operated switches which assure that as the patient is rotated toward a side position the platform will be elevated, while as the patient is rotated away from a side position the platform will be lowered.

Several safety devices are also provided for terminating rotation and lowering of the platform as well as other operational movements of the rotator if continued movement would injure the patient or damage the apparatus.

A method of conducting an X-ray examination of a patient is provided wherein the patient is positioned on a platform rotatable about a longitudinal axis. The center of interest to be studied is located, and the platform is moved laterally to align the center of interest with the X-ray beam axis. The platform is then rotated and is simultaneously laterally adjusted to maintain the alignment of the center of interest with the X-ray beam.

Accordingly, it is a general object of the present invention to provide a novel and improved patient rotator apparatus and methods of conducting X-ray studies.

Other objects and a fuller understanding of the invention may be had by referring to the following description and claims taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an X-ray table including a patient rotator constructed in accordance with the present invention;

FIG. 2 is a side elevational view of the patient rotator of FIG. 1;

FIG. 3 is a top plain view of the patient rotator;

FIG. 4 is an enlarged cross-sectional view of one end of the patient rotator as seen from the plane indicated by the line 4--4 in FIG. 3;

FIG. 5 is a cross-sectional view as seen from the plane indicated by the line 5--5 in FIG. 3 of the patient rotator end shown in FIG. 4, the view being at a reduced scale from that of FIG. 4;

FIGS. 6-9 are schematic views illustrating the procedure of adjusting the rotator to maintain a center of interest within the patient along the axis of an X-ray beam during rotation;

FIG. 10 is a cross-sectional view on the same scale as FIG. 5 of a portion of the patient rotator as seen from the plane indicated by the line 10--10 in FIG. 3; and,

FIG. 11 is a schematic diagram of the electro-mechanical control system which automatically elevates and lowers the patient rotator platform during rotation.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A tiltable X-ray table is shown generally at 10 in FIG. 1. The table is provided with a patient rotator in accordance with the present invention. The table 10 includes a stationary base or pedestal 11 and a body 12 which is tiltable in the conventional manner. The referenced patent discloses and claims such a table having a tiltable body.

A ceiling mounted X-ray tube housing assembly 13 is disposed above the table 10. An X-ray tube, not shown is carried within the housing assembly 13 and arranged to emit a beam of X-radiation along an axis 14. An X-ray responsive device, such as a film carrying Bucky Tray 15, is carried by the table 10 and disposed to intercept the X-ray beam.

A pair of supporting structures 20, 21 are secured to opposite ends of the table body 12. A patient supporting cradle or platform 22 is rotatably mounted by the end structures 20, 21 for rotation about a longitudinal axis 23. As will be explained in greater detail, the end structures 20, 21 house mechanisms which maintain a selected center of interest in alignment with the X-ray beam axis 14 as the patient is rotated about the longitudinal axis 23. This is accomplished by shifting the longitudinal axis 23 laterally as indicated by the arrows 24, 25 during rotation of the platform 15 to keep the center of interest aligned with the beam axis 14.

Another feature of the invention, as will be explained in greater detail, is the provision of an electro-mechanical control system for elevating and lowering the platform 22 during rotation to maintain a minimal patient-to-film distance. As the patient is rotated onto either of his sides, the platform 22 is elevated to provide clearance for such rotation. As the patient is rotated away from a side-position, the platform 22 is lowered to keep the lowermost regions of the patient at a minimal distance from the film.

The rotatable cradle or platform 22 comprises a trough-like center panel 30 suspended between a pair of elliptical-shaped end panels 31, 32. The end panels 31, 32 are supported on stub shafts 33, 34 journaled by the end structures 20, 21.

As is best seen in FIG. 10, an inflatable air mattress 35 is carried on the center panel 30. The air mattress 35 is useful not only to assure the patient's comfort, but also to adjust the combined center of gravity of the patient and the platform 22 for rotation. Where a relatively petite patient is positioned on the platform, for instance, the mattress 35 is inflated to elevate the patient so that the combined center of gravity of the patient and the platform will more nearly lie along the longitudinal axis of rotation 23.

The patient can be held in the cradle 22 during rotation by conventional means such as a harness, straps and tape, or by such improved means as are disclosed in the referenced application. The referenced application relates to the use of a thin transparent plastic sheet which is disposed over the patient to establish a vacuum evacuable chamber between the plastic sheet and the supporting cradle. Once this chamber is partially vacuum evacuated, ambient air pressure serves to hold the patient against the cradle, even with the cradle entirely inverted.

The end structures 20, 21 comprise box-like housings 40, 41 which open toward the end plates 31, 32. The housings 40, 41 are each secured to a pair of elongate mounting brackets 42. The brackets 42 are positioned over and secured to opposite ends of a pair of rails 43 forming part of the table body 12.

Housed within each of the housings 40, 41 is a mechanism which mounts the platform for movement laterally from side to side and transversely up and down. Referring to FIGS. 4 and 5, the end structure 20 is shown in greater detail. The stub shaft 33 is journaled by a pair of roller bearings 50, 51. The bearings 50, 51 are supported in opposite end regions of a sleeve 52. A bearing block 53 has a through aperture 54 which receives and supports the sleeve 52.

A reversible rotational drive motor 60 is mounted atop the bearing block 53 to effect rotation of the stub shaft 33. The motor 60 is coupled through a gear reducer 61 to a drive sprocket 62. An endless roller chain 63 is reeved around the sprocket 62 and around a sprocket 64. The sprocket 64 is secured by fasteners 65 to a bracket 66 and to a metallic clutch disc 67. A sleeve bearing 68 rotatably mounts this sprocket, bracket and disc assembly on the shaft 33.

An electromagnetic clutch 70 selectively drivingly couples the sprocket 64 to the stub shaft 33. The clutch 70 includes a winding 71 encased by a metallic housing 72. A central mounting hub 73 rigidly mounts the housing 72 on the shaft 33. When current is supplied to the winding 71, the metallic clutch disc 67 is clamped against the housing 72 to establish a driving connection.

As will be apparent, concurrent energization of the rotational drive motor 60 and the electromagnetic clutch 70 will enable the motor ,60 to rotate the platform 22. Energization of the motor 60 without concurrent energization of the clutch 70 will cause the assembly of the sprocket 64, the bracket 66 and the disc 67 to rotate relative to the shaft 33. This latter movement is utilized to adjust the patient rotator so it will maintain a center of interest within the patient aligned with the X-ray beam axis 14.

The bearing block 53 is supported for lateral movement relative to the housing 20. As is best seen in FIG. 5, a pair of laterally extending rods 75, 76 extend through apertures 77, 78 in the bearing block 53. Sleeves 79 positioned in the apertures 77, 78 slidably receive the rods 75, 76.

A pair of vertical positioning blocks 80, 81 rigidly engage opposite ends of the rods 75, 76 and mount the rods for transverse up and down movement. A pair of upstanding guide rods 82, 83 are secured at opposite ends to the housing 40. The guide rods 82, 83 extend through apertures 84, 85 in the positioning blocks 80, 81. Sleeves 86 positioned in the apertures 84, 85 slidable receive the rods 82, 83.

The lateral positioning of the bearing block 53 is controlled by a guide structure which is interposed between the housing 40 and the bracket 66. Referring to FIG. 4, a guide plate 90 having a vertically extending slot 91 is mounted within the housing 40. A guide pin 92 extends through the lot 91. An apertured mounting block 93 mounts the guide pin 92. The block 93 is supported by a threaded rod 94 which is threaded through an aperture 95 in the block 93.

The rod 94 is journaled for rotation by a pair of sleeves 96, 97 carried by the bracket 66. Rotation of the rod 94 in one direction will cause the guide pin 92 to translate radially outwardly of the shaft 33 as indicated by the arrow 98. Rotating the rod 94 in the opposite direction will cause the guide pin 92 to translate radially inwardly in the direction opposite arrow 98.

The radially inward travel of the block 93 is limited by a stop washer 99 carried by the rod 94 adjacent the sleeve 96. In its fully radially inward position, the guide pin 92 is axially aligned with the shaft 33.

The radially inward and outward positioning of the guide pin 92 is controlled by a reversible guide pin adjuster motor 100 supported on the bracket 66. A pair of S-shaped spacers 101 are interposed between the adjuster motor 100 and the bracket 66. Threaded fasteners 102 secure the spacers 101 to the bracket 66 and to the adjuster motor 100. The motor drive shaft 103 is directly coupled to the rod 94.

The vertical or transverse positioning of the platform 22 is controlled by a chain drive mechanism which supports vertical positioning blocks 80, 81. A pair of endless roller chains 105, 106 are coupled by links 107, 108 to the blocks 80, 81. Each of the chains is reeved around upper and lower sprockets 109, 110. The upper sprockets 109 are idler sprockets which are rotatably supported by the housing 40. The lower sprockets 110 are mounted on drive shafts 111, 112 which along opposite sides of the platform 22 between the end structures 20, 21. The drive shafts 111, 112 are interconnected for synchronous rotation by an endless roller chain 113. The chain 113 is reeved around a pair of sprockets 114, 115 mounted on the shafts 111, 112.

A reversible vertical positioning motor 120 is coupled to the shafts 111, 112 to control the vertical or transverse positioning of the platform 22. As is best seen in FIGS. 2 and 3, the vertical positioning motor 120 is housed within the end structure 21. A gear reducer 121 couples the motor 120 to the shaft 112. Since the shafts 111, 112 are interconnected by chains 113, energization of the motor 120 will cause concurrent rotation of the shafts 111, 112 and concurrent movement of the positioning blocks 80, 81. Operation of the motor 120 in one direction will cause concurrent elevation of the platform 22 while motor operation in the opposite direction will cause lowering of the platform 22.

As will be apparent from the foregoing description, the end structures 20, 21 house substantially identical platform positioning mechanisms, with the exception that the end structure 20 houses the rotational drive system including drive motor 60 and clutch 70, as well as the lateral guide adjuster system including the adjuster motor 100, while the end structure 21 houses the vertical positioning drive system including the vertical positioning motor 120.

The procedure involved in adjusting the mechanism housed in the end structure 20 to maintain a selected center of interest along the beam axis 14 during rotation of the platform 22 is illustrated schematically in FIGS. 6-9. The FIGS. 6-9 depict in end view the elliptical platform end plate 31, the guide slot 91, and the guide pin 92, and the bracket 66 which supports the threaded rod 94 on which the guide pin 92 is carried. The X-ray source 13 and beam axis 14 are also shown.

At the initiation of the procedure, the guide pin 92 is positioned in alignment with the axis of rotation 23 of the platform 22. Assume the selected center of interest within the patient to be represented by the dot 130. The radial distance of the dot 130 from the axis 23, as represented by the arrow 131 is determined and the guide pin adjuster motor 100 is actuated to reposition the guide pin 92 at an identical radial distance from the axis 23, as shown in FIG. 7.

The rotational drive motor 60 is then actuated without concurrent actuation of the clutch 60. As has previously been described, actuation of the motor 60 without concurrent clutch 70 actuation will cause the bracket 66 to rotate relative to the platform 22. This rotation is continued until, as shown in FIG. 8, the guide pin 92 is brought into alignment with the center of interest 130. The effect of the above-described procedure is to laterally reposition the platform 22 to bring the center of interest 130 into alignment with the X-ray beam axis 14.

The clutch 70 is then actuated to drivingly connect the motor 60 to the platform 22. By this arrangement, further rotation of the motor 60 will cause the platform 22 to rotate, as shown in FIG. 9. Since the guide pin 92 is aligned with the center of interest 130, and since the guide pin 92 is confined to translatory movement along the guide slot 92 which is aligned with the beam axis 14, the platform 22 will be caused to move laterally during rotation to keep the center of interest 130 aligned with the beam axis 14.

The patient rotator is provided with several limit switches to terminate motor operation where continued motor operation might harm the apparatus or the patient. A pair of normally closed limit switches 140, 141 are disposed at opposite ends of the bracket 66, as shown in FIG. 4. As the block 93 approaches either end of the threaded rod 94, the switches 140, 141 serve to terminate operation of the motor 100, as will be described in greater detail.

A series of normally closed limit switches 142 are provided beneath the platform 22 as shown in FIG. 10. A flexible cover 143 is disposed across the opening between the side rails 43. The limit switches 142 are provided at spaced intervals along the cover 143 and are connected in electrical series with the rotational drive motor 60 and with the vertical drive motor 120, as will be explained in greater detail. By this arrangement, if the platform 22 is rotated or lowered to bring any portion of the patient or platform into contact with the cover 143, the switches 142 will terminate the operation of the motors 60 and 120.

The electro-mechanical control system which effects the various movements of the platform 22 is shown schematically at FIG. 11. A pair of cams A and B are carried by the platform 22 for rotation therewith. As cam A rotates with the platform 22, the configuration of its peripheral surface selectively opens and closes a pair of switches 150, 151. As cam B rotates with the platform 22, the configuration of its peripheral surface selectively opens and closes a switch 152.

The actuating circuit includes a pair of conductors 155, 156 which are adapted for connection to a suitable 120 volt AC source of electrical energy. A pair of fuses 157, 158 couple the conductors 155, 156 to a second pair of conductors 159, 160. Each of the motors 60, 100 and 120 as well as the clutch 70 are selectively connected in parallel between the conductors 159, 160 by a series of switches and relays as will be described presently.

The rotational drive motor 60 is directionally reversible depending upon whether power is supplied to terminals 161, 163. The common terminal 161 is connected to the conductor 159. The terminals 162, 163 are selectively connected to the conductor 160 through a rotational control switch 164. The switch 164 has a movable contact 165 which is spring-biased to a centered position between two contacts 166, 167. Movement of the contact 165 to the left closes contacts 165, 166 thereby connecting the conductor 160 to a conductor 168. Movement of the contact 165 to the right closes contacts 165, 167 thereby connecting the conductor 160 to a conductor 169. Normally closed contacts of the cover-actuated switches 142 are interposed between the conductors 167, 169 and the motor terminals 162, 163. By this arrangement, unless and until the patient or platform 22 are brought into contact with the cover 143 so as to open the switches 142, the rotational control switch 164 will be operable to energize the motor 60. Movement of the contact 165 to the left will energize the motor 60 for clockwise rotation while movement to the right will cause counterclockwise rotation.

Energization of the electromagnetic clutch 70 is controlled by a clutch control switch 170. The switch 170 has a movable contact 172 which selectively opens and closes with a contact 172 to electrically connect the conductor 160 with a conductor 173. The clutch winding 71 is connected across a pair of conductors 174, 175. A full wave rectifier network 176 is interposed between the conductors 159, 173 and 174, 175 to supply the clutch winding 71 with direct current at such times as the switch contacts 171, 172 are closed.

The guide pin adjuster motor 100 is directionally reversible depending upon whether power is supplied to terminals 180, 181 or to terminals 180, 182. The common terminal 180 is connected to the conductor 159. The terminals 181, 182 are selectively connected to the conductor 160 through a guide pin adjuster switch 183. The switch 183 has a movable contact 184 which is spring-biased to a centered position between two contacts 185, 186. Movement of the contact 184 to the left closes contacts 184, 185 thereby connecting the conductor 160 to a conductor 187. Movement of the contact 184 to the right closes contact 184, 186 thereby connecting the conductor 160 to a conductor 188. The conductors 187, 188 connect respectively with the motor terminals 181, 182. By this arrangement, movement of the contact 184 to the left will cause energization of the motor 100 in a direction which will move the guide pin 92 radially outwardly from the longitudinal axis 23, while movement to the right will cause radially inward movement of the guide pin 92.

The vertical drive motor 120 is directionally reversible depending upon whether power is supplied to terminals 190, 191 or to terminals 190, 192. The common terminal 190 is connected to the conductor 159. The terminals 191, 192 are selectively energized either manually through a vertical drive switch 193 or automatically in response to the supply of current to either of the conductors 168, 169, as will be described presently.

Selective automatic energization of the vertical drive motor 120 in up and down directions is controlled by the cam operated switches 150, 151. The cam A is configured so as to drive the platform 22 up when the patient is rotated onto his side from a prone or supine position, and down as the patient is rotated away from a side position and toward either a prone or supine position. The atient is kept at a minimal and relatively constant distance to the film carried in the Bucky tray 15.

The cam operated switch 150 has a movable contact 195 connected to the conductor 168 and selectively engageable with contacts 196, 197. The contacts 196, 197 are connected by conductors 198, 199 to the limit switches 140, 141 carried on the bracket 66. A conductor 200 connects the limit switch 140 to the motor terminal 191. A conductor 201 connects the limit switch 141 to normally closed contacts of the cover carried limit switches 142. Another conductor 202 connects the cover carried switch 142 to the motor terminal 192.

The cam operated switch 151, in similar fashion, has a movable contact 205 connected to the conductor 169 and selectively engageable with contacts 206, 207. The contacts 206, 207 connect respectively with the conductors 198, 199.

With this arrangement of cam operated switches 150, 151, if the rotation control switch 164 is actuated to supply current to either of the conductors 168, 169 the switches 150, 151 will effect energization of the vertical drive motor 120. For example, if the platform is positioned horizontally as shown in FIGS. 1 and 2, Cam A will be positioned as shown in FIG. 11. The contacts of the switches 150, 151 will be in their normally closed position. Accordingly, regardless of whether the platform is rotated clockwise or counterclockwise by the switch 164, current from the conductors 168, 169 will be supplied through the switches 150, 151 to the conductor 198 to raise the platform. So long as rotation continues toward positioning the patient on his side, the platform will continue to elevate.

Once the patient is positioned on his side, i.e. once the platform and the Cam A have rotated 90.degree., the cam will open the normally closed contacts 195, 196 and 205, 206 of the switches 150, 151 and close the normally open contacts 195, 197 and 205, 207. Accordingly, continued rotation in either clockwise or counterclockwise directions will result in the transmission of current from the conductors 168, 169 through the switches 150, 151 to drive the motor 120 in a platform lowering mode.

The vertical drive switch 193 provides a second control for elevating and lowering the platform. The switch 193 has a movable contact 210 which is spring biased to a centered position between a pair of contacts 211, 212. The movable contact 210 is connected to a conductor 213. A pair of normally closed solenoid operated switches 214, 215 are coupled in series between the conductors 160, 213. Electrical connection is established between the conductor 160, and the switch contact 210 so long as the switches 214, 215 remain closed.

The switches 214, 215 constitute a safety means for preventing the concurrent energization of the motor 120 in opposite directions. The switches 214, 215 are actuated respectively by solenoids 216, 217. When the solenoids 216, 217 are energized, the switches 214, 215 are opened, thereby breaking the electrical connection between the switch 193 and the conductor 160.

The solenoid 216 is connected between the conductors 159, 169 so as to be energized when the rotational control switch 164 is moved to its counterclockwise rotation position. The solenoid 217 is connected between the conductors 159, 168 so as to be energized when the rotational control switch 164 is moved to its clockwise rotation position. Accordingly, whenever the rotation control switch 164 is positioned to supply current to either of the conductors 168, 169 thereby energizing the vertical drive motor as described above, the supply of current to the vertical drive switch 193 is interrupted so as to disable the vertical drive switch 193 from also energizing the motor 120.

The vertical drive switch contact 211 connects directly with the conductor 198. The contact 212, however, connects with a conductor 220, and the cam operated switch 152 is interposed between the conductors 220, 199.

Cam B is configured such that the normally closed contacts of the switch 152 will be closed only when the platform 22 is positioned substantially horizontally. Accordingly, the switch 152 will only permit the platform to be driven downward by means of the vertical drive switch 193 at such times as the platform is positioned in a horizontal attitude.

The operation of the patient rotator is ordinarily initiated with the table body 12 and the platform 22 in substantially horizontal positions. A patient to be examined is positioned on the platform 22 and secured thereto by suitable straps, harness, or tape, etc., or by the vacuum means disclosed in the reference application.

When the general location is known of the center of interest within the patient to be studied, the rotator guide mechanism is adjusted, as has been described, to maintain the center of interest along the beam axis 14 during rotation. When the location of the center of interest is not initially known, X-ray fluoroscopy techniques are used to locate the center of interest.

During rotation of the patient the platform 22 will be elevated automatically as has been described as the patient is rotated toward a side position, and will be lowered automatically as the patient is rotated away from a side position. If, at anytime, the patient or platform is brought into contact with the cover 143, the limit switches 142 will prevent further rotation or downward movement of the platform until the platform has been elevated by means of the vertical drive switch 193. Once the study is completed, the platform is rotated to its horizontal position for the patient's departure.

Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

Claims

What is claimed is:

1. A patient rotator for rotating a patient while maintaining a center of interest within the patient along an examination axis as the patient is rotated, comprising:

a. a supporting structure;

b. a patient support adapted to receive and support a patient;

c. mounting means mounting said support on said tructure such that said support is rotatable about a longitudinal axis of rotation while said axis of rotation is shiftable laterally of the examination axis; and

d. control means coupled to said mounting means for laterally shifting said axis of rotation relative to said examination axis during rotation of said support as is required to maintain a preselected center of interest within the patient in alignment with the examination axis.

2. The patient rotator of claim 1 wherein said control means is adjustable such that a selected center of interest located anywhere within the body of a patient positioned on said support can be brought into alignment with the examination axis and maintained along the examination axis during rotation of said support.

3. The patient rotator of claim 2 wherein:

a. said mounting means additionally serves to mount said support for movement in directions parallel to the examination axis; and,

b. said control means additionally serves to move said support in directions parallel to the examination axis in response to rotation of said support in order to maintain portions of the patient within a preselected plane extending perpendicular to the examination axis.

4. The patient rotator of claim 3 wherein the examination axis extends generally vertically and said portions of said patient comprise the lowermost portions of the patient which are maintained in within a generally horizontal plane during rotation of said support such that the patient is essentially supported at a constant height.

5. The patient rotator of claim 1 wherein said control means comprises guide means carried by said structure establishing a guide path in a plane including the examination axis, and positioning means carried by said support and cooperatively engaging said guide means to effect lateral movement of said support relative to the examination axis during rotation of said support.

6. The patient rotator of claim 5 wherein said positioning means is movably adjustable relative to said support whereby said positioning means can be disposed along an axis parallel to said axis of rotation and extending through a center of interest located substantially anywhere within the body of a patient positioned on said support in order to maintain said center of interest along the examination axis during rotation of said support.

7. A patient rotator for use in conjunction with an X-ray table having a body and an X-ray apparatus designed to emit a beam of radiation along a beam axis, comprising:

a. a supporting structure adapted to be mounted on the table body;

b. an elongated patient support adapted to receive and support a patient during rotation about an axis disposed generally longitudinally of said support and in a plane which is substantially perpendicular to the beam axis;

c. mounting means mounting said support on said structure such that said support is rotatable about said longitudinal axis while said longitudinal axis is shiftable laterally of the beam axis within said plane; and,

d. control means connected to said mounting means for moving said support to selectively align a center of interest within a patient positioned on said support with the beam axis, and for laterally shifting said longitudinal axis during rotation of said support to maintain said center of interest in alignment with the beam axis.

8. The patient rotator of claim 7 wherein said control means comprises:

a. guide means carried by said structure establishing a guide path in a plane including the beam axis; and,

b. positioning means carried by said support and cooperatively engaging said guide means to effect lateral movement of said support relative to the beam axis during rotation of said support;

c. whereby, when said guide means is disposed along an xis parallel to said longitudinal axis and extending through said center of interest, said support will be moved laterally of the beam axis during rotation of said support as required to maintain said center of interest in alignment with the beam axis.

9. The patient rotator of claim 7 wherein said mounting means additionally serves to mount said support for movement in directions parallel to the beam axis, and a drive means is provided to move said support along the beam axis in accordance with the angle of rotation of said support.

10. The patient rotator of claim 9 wherein said drive means is operable to elevate said support as the patient is rotated onto either of his sides, and is operable to lower said support as the patient is rotated away from a side position.

11. An X-ray table comprising:

a. a pedestal;

b. a body movably supported on said pedestal;

c. a patient support adapted to receive and support a patient during rotation about an axis disposed generally longitudinally of said support;

d. mounting means rotatably and translatably mounting said support on said body such that said support is rotatable about said longitudinal axis while said longitudinal axis is translatable laterally in directions generally perpendicular to a preselected examination axis which extends through a preselected center of interest within a patient positioned on said support; and,

e. control means connected to said mounting means to laterally translate said longitudinal axis during rotation of said support to maintain said preselected center of interest along said examination axis;

f. whereby an X-ray beam can be directed along said examination axis to view the center of interest during rotation of the patient and center of interest will remain in the path of the beam during the entire rotation.

12. The X-ray table of claim 11 wherein a safety means is provided for terminating further rotation of the support upon sensing engagement between top surface portions of said body and either portions of the support or portions of a patient positioned on the support.

13. The X-ray table of claim 11 wherein said control means is adjustable selectively move said support such that a selected center of interest substantially anywhere within the patient's body can be brought into alignment with said examination axis and maintained in alignment therewith during rotation.

14. The X-ray table of claim 13 wherein said control means includes:

a. a guide track positioned within a plane including said examination axis;

b. positioning means engaging said guide track and coupled to said support for moving said support laterally to maintain said selected center of interest aligned with said examination axis; and,

c. motor driven adjuster means for movably positioning said positioning means relative to said support.

15. The X-ray table of claim 14 wherein said motor driven adjuster means includes motor driven means for moving said positioning means radially inwardly and outwardly of said longitudinal axis of rotation.

16. The X-ray table of claim 15 additionally including power drive means including a drive motor for rotating said support wherein said drive motor is selectively coupled to said support through an electromagnetic clutch which, when energized will cause said support to rotate in response to rotation of said drive motor, but when de-energized will cause rotation of said positioning means relative to said support in response to rotation of said drive motor.

17. The X-ray table of claim 11 additionally including:

a. first power drive means for rotating said support;

b. second power drive means for elevating and lowering said support; and,

c. said control means additionally serves to effect operation of said second power drive means to selectively elevate or lower said support in response to actuation of said first power drive means.

18. The X-ray table of claim 17 wherein said control means is operable to maintain the patient at a relatively constant height above the table body by elevating said support as the patient is rotated toward a side position, and by lowering said support as the patient is rotated away from a side position.

19. The X-ray table of claim 18 wherein a safety means is provided for terminating further rotation of the support upon sensing engagement between top surface portions of said body and either portions of the support of portions of a patient positioned on the support.

20. A method of conducting an X-ray examination of a patient comprising the steps of:

a. positioning the patient on a support rotatable about a longitudinal axis;

b. locating a center of interest within the patient which is to be studied from a plurality of directions;

c. aligning the center of interest with the beam axis of an X-ray apparatus; and,

d. moving said support to shift said longitudinal axis laterally relative to the beam axis during rotation of the platform to maintain the center of interest in alignment with the beam axis.

21. The method of claim 20 additionally including the step of moving said support to adjust the position of the patient along the beam axis during rotation of the support to maintain selected portions of the patient at a relatively constant distance from an X-ray sensitive device.

22. The method of claim 21 wherein the position of the patient along the beam axis is adjusted by elevating and lowering the longitudinal axis of the support in accordance with the angle of rotation of the patient such that the longitudinal axis is elevated as the patient is rotated toward a side position, and is lowered as the patient is rotated away from a side position.

23. In a patient rotator for rotating a patient during an examination including a supporting structure; a patient support on the structure adapted to receive and support a patient for rotation about a longitudinal axis of rotation while an X-ray study of a region of interest in the patient is conducted with an X-ray beam emitted along an examination axis, the improvement characterized by means for maintaining the region of interest along the examination axis, the mechanism including mounting means mounting said support on said structure for rotation about said axis of rotation while said axis of rotation is shiftable laterally of the examination axis; and control means coupled to said mount for laterally shifting said axis of rotation during rotation of said support to maintain a region of interest in alignment with the examination axis.

24. The patient rotator of claim 23 wherein said control means is adjustable to move said support such that a selected center of interest located anywhere within the body of a patient positioned on said support can be brought into alignment with the examination axis and maintained along the examination axis during rotation of said support.

25. The patient rotator of claim 23 wherein said mounting means additionally serves to movably mount said support for movement in directions parallel to said examination axis.