X-ray shield arrangement for operating room

Back-scattered x-rays incident on a person working with a patient on an operating table are reduced by upper and lower x-ray shield panels mounted so they can be turned relative to each other about a common vertical axis. The panels are thick enough and have proximate horizontal edges close enough to each other to substantially attenuate the back-scattered x-rays incident on front faces of the panels and a gap between the edges while the panels are aligned. The panels pivot about the vertical axis to form an opening enabling the person's hand(s) and forearm(s) to extend through. A hinge connects the upper and lower panels to a third panel. In a second embodiment, the upper and lower panels are moved up and down together, while the lower panel remains aligned with a fixed fourth panel for protecting the person's legs.

FIELD OF THE INVENTION

The present invention relates generally to a shielding apparatus and method for an operating room equipped with x-ray diagnostic equipment and more particularly to such a method and apparatus wherein an x-ray shield panel includes at least two segments, capable of turning relative to each other about a substantially vertical axis.

BACKGROUND ART

Modern operating rooms typically include a table on which a patient lies during the operating procedure, and diagnostic equipment in the form of an x-ray source and an x-ray detector, is located on a gantry with the patient and operating table between the x-ray source and detector. The gantry is rotatable about a horizontal axis so that a surgeon viewing a display responsive to the detector is provided with real time display of the tissue being operated on. During the procedure, the patient is irradiated by x-rays for prolonged intervals and is moved relative to the source of x-rays by providing the table with motors and a linkage that move the table and patient relative to the platform in a plane parallel to the floor. At other times, it is essential that the table and patient remain stationary, a result achieved by providing the table with a braking arrangement for holding the table in situ relative to the platform.

The x-ray source can be activated to different intensity levels. The x-ray source is activated to a high intensity level, referred to as the cine mode, to provide an intensity sufficient to expose cine film and to provide fluoroscopy. The x-ray source is activated to a lower intensity, referred to as the fluoroscopy mode, when only fluoroscopy and no exposure of cine film is required. Typically, there is approximately a 4:1 ratio between the intensity level of the cine and fluoroscopy modes.

Because the surgeon and one or more assistants stand next to the operating table, they are constantly exposed to x-rays back-scattered from the patient and/or table unless adequate shielding is provided. The accumulated effect of the back-scattered radiation over many years of conducting surgical procedures may have deleterious effects on the health of the surgeon and assistant(s), and may induce cancer.

In an attempt to reduce the x-ray exposure to a surgeon and assistant(s) standing next to the side of an operating table while an x-ray source is irradiating a patient, the surgeon and assistant(s) usually wear leaded eyeglasses, a lead thyroid covering and a lead apron which covers the chest, abdomen and thighs but leaves uncovered the arms, hands, legs below the knees and head. The radiation protection is only partially effective in blocking radiation and leaves substantial parts of the body uncovered. The amount of back-scattered x-ray radiation incident on the surgeon and assistant(s), particularly during the cine mode, is believed to be substantial enough to cause damage to the surgeon and assistant(s) over a prolonged time period.

In some instances, the surgeon and assistant(s) stand behind lead shield panels that are transparent to optical energy but substantially opaque to x-rays. The lead shield panels are typically unitary structures fixedly mounted on frames carrying casters, as disclosed in my U.S. Pat. No. 5,185,778, incorporated herein by reference.

The panels are made of lead glass having sufficient thickness to substantially attenuate the back-scattered x-rays and thereby protect the surgeon and assistants. The panels do not enable the surgeon and/or assistants easy access to the patient during the operating procedure. Consequently, if access to the patient is necessary during the procedure and while the patient is being x-rayed, there is a high likelihood of sensitive body portions of the surgeon and/or assistant(s) being irradiated with undesirable doses of back-scattered x-ray radiation.

It is, accordingly, an object of the present invention to provide a new and improved method of and apparatus for shielding surgeons and/or assistants from x-rays during surgery while x-rays are being used for diagnostic purposes.

An additional object of the present invention is to provide a new and improved method of and apparatus for shielding critical body parts of surgeons and/or assistant(s) during an operating procedure that is accompanied by a patient being exposed to diagnostic x-rays, wherein the shield arrangement enables relatively easy access to the patient.

Another object of the present invention is to provide a new and improved shield panel arrangement for an operating room including x-ray diagnostic equipment, wherein the shield panel arrangement includes moving parts that are relatively easily moved, despite the substantial weight and density of the shield panels.

SUMMARY OF THE INVENTION

According to one aspect of the invention, there is provided an apparatus for reducing back-scattered x-rays incident on a person working with a patient on an operating table, wherein the patient is exposed to x-rays from an x-ray source while on the table so that the back-scattered x-rays result from x-rays from the source being incident on the patient and/or table. The apparatus comprises an upper x-ray shield panel and a lower x-ray shield panel arrangement. The upper x-ray shield panel and the lower x-ray shield panel arrangement have thicknesses between front and back faces thereof and respectively have lower and upper edges in close enough proximity to each other to substantially attenuate the back-scattered x-rays incident on (a) the front face of the upper x-ray shield panel, (b) the lower x-ray shield panel arrangement, and (c) a gap between the edges while the front faces of the upper x-ray shield panel and lower x-ray shield panel arrangement are aligned and parallel to a proximate edge of the operating table. The upper shield panel is transparent to visible optical energy and pivotable about a vertical axis relative to the lower shield panel arrangement to enable one or both hands and one or both forearms of a person standing behind the back faces of the upper and lower shield panels to extend through an open region between the lower and upper edges. The opening results from pivoting of the upper x-ray shield panel relative to the lower x-ray shield panel arrangement about the vertical axis. The upper x-ray shield panel and lower x-ray shield panel arrangement together have a height and widths sufficiently greater than the height and width of the person standing behind the back faces of the upper panel and lower panel arrangement to substantially prevent the back-scattered x-rays incident on the front faces of the upper x-ray shield panel and the lower x-ray shield panel arrangement from being incident on the portion of the person behind the back faces while the front faces are aligned.

Preferably, the upper x-ray shield panel and the lower x-ray shield panel arrangement have aligned vertically extending edges that are substantially coincident with the vertical axis. Another x-ray shield panel is preferably provided. The another x-ray shield panel has front and back faces and a vertically extending edge in sufficiently close proximity to the aligned vertically extending edges of the upper x-ray shield panel and lower x-ray shield panel arrangement to substantially attenuate the back-scattered x-rays incident on (1) the aligned vertically extending edges of the upper x-ray shield panel and the lower x-ray shield panel arrangement and (2) the vertically extending edge of the another x-ray shield panel. The front face of the another x-ray shield panel is positionable at a non-zero angle, e.g. 90°, relative to the front faces of the upper x-ray shield panel and the lower x-ray shield panel arrangement.

The another x-ray shield panel preferably has a height equal to or greater than the combined heights of the upper x-ray shield panel and the lower x-ray shield panel arrangement.

The vertically extending edge of the another x-ray shield panel is preferably pivotable relative to the aligned vertically extending edges of the upper x-ray shield panel and the lower x-ray shield panel arrangement to enable the another panel to be turned by a suitable angle, e.g., 90°, relative to the aligned upper panel and lower panel arrangement and the proximate edge of the operating table.

Preferably, to maximize attenuation of back-scattered x-rays, the another x-ray shield panel has a horizontal extent substantially at a right angle to the faces and a first segment extending slightly beyond the front faces toward the operating table and a second segment extending by a substantial distance beyond the back faces away from the operating table.

In one embodiment, the lower x-ray shield panel arrangement includes a single x-ray shield panel.

In a second embodiment, the lower x-ray shield panel arrangement includes first and second x-ray shield panels, arranged so the first panel is generally above the second panel. The first x-ray shield panel has (1) a lower edge and (2) an upper edge corresponding with the upper edge of the lower x-ray shield panel arrangement. The second x-ray shield panel has an upper edge below the lower edge of the first x-ray shield panel and a lower edge in close proximity to the floor or on the floor. The first and upper x-ray shield panels are arranged so they can have different vertical positions so that the gap between the upper edge of the first x-ray shield panel and the lower edge of the upper x-ray shield panel is maintained constant at the different vertical positions. The first and second x-ray shield panels are arranged so that (1) the upper and lower edges of the second x-ray shield panel are maintained at the same vertical position while the first and upper x-ray shield panels are at all of the different vertical positions, and (2) the upper edge of the second x-ray shield panel is above the lower edge of the first x-ray shield panel at all of the different vertical positions.

Preferably, the upper and first x-ray shield panels are drivingly connected to a pulley arrangement so the upper and first x-ray shield panels can be driven to the different vertical positions. The pulley arrangement includes a wheel and a counterweight. The counterweight is on a side of the wheel different from the upper and first x-ray shield panels and weighs about the same as the combined weights of the upper and first x-ray shield panels.

Another aspect of the invention relates to a method of using the foregoing apparatus to reduce back-scattered x-rays incident on a person working with a patient on an operating table.

The method comprises forming the open region between the bottom edge of the upper panel and the upper edge of the lower panel arrangement by causing the upper x-ray shield panel to be turned toward the operating table while maintaining the lower x-ray shield panel arrangement substantially parallel to a proximate edge of the table while the patient is exposed to x-rays from the x-ray source. One or both hands and one or both forearms of a person located behind the shield panels are extended through the open region while the patient is exposed to x-rays from the x-ray source while the remainder of the person is behind the back faces.

In those embodiments wherein the lower x-ray shield panel arrangement includes the first and second x-ray shield panels, the method preferably further comprises abutting the lower edge of the upper x-ray shield panel against an upper surface of the patient on the operating table after the table has been vertically locked in position for the comfort of the surgeon. Such a position of the upper panel aids in reducing back-scattered x-rays incident on the person while the patient is exposed to x-rays from the x-ray source and one or both hands and one or both forearms of the person extend through the open region while the remainder of the person is behind the back faces of the shield panels.

The above and still further objects, features and advantages of the present invention will become apparent upon consideration of the following detailed description of specific embodiments thereof, especially when taken in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE DRAWINGS

The preferred embodiment of the present invention is described in conjunction with a cardiac catheterization procedure. It is to be understood, however, that the principles of the invention are applicable to any surgical or radiological procedure wherein a patient is subject to x-ray radiation for prolonged time periods and an operator and assistant(s) attending the patient, e.g., a surgeon or radiologist and nurse(s), are subject to x-rays back-scattered from the patient and/or operating table on which the patient is lying.

Reference is now made toFIG. 1of the drawing wherein operating table11is mounted on platform12, in turn fixedly mounted on floor13so that the operating table extends in a horizontal plane parallel to the floor. Platform12includes X-Y linkages (not shown) for moving table11in the horizontal plane in directions of X and Y axes and motors, as well as a braking mechanism, and an elevator (not shown) for driving table11up and down, i.e., in the direction of the z axis; the linkages, motors, braking mechanism and elevator are well known to those skilled in the art. The linkages and motors for the X and Y axes enable forces manually applied by the surgeon to the table during the procedure to move the table in the horizontal plane, even though a relatively heavy patient is lying on table11. The X-Y linkages and motor in platform12are controlled by the surgeon selectively activating a button, so that when the button is pushed, the manually-imparted forces cause table11to move in the horizontal plane. When the button is not activated, the X-Y linkages and the motors in platform12are braked by the braking mechanism in the platform to prevent movement of table11relative to platform12and the floor13. The z axis position of table11is established prior to the procedure being initiated so that the patient is at a height above floor13that enables the operator to perform the procedure with the greatest ease and comfort.

X-ray source14and x-ray detector15, in the form of an image intensifier, are mounted on gantry16so that the tube and detector are mounted on opposite sides of table11while the patient is on the table. Gantry16is mounted for rotation on column17, located on floor13. Circuitry in x-ray source14and image-intensifier15is controlled by electric power and signals coupled to them from an x-ray controller (not shown) via cable19. The x-ray image is transmitted via cable20from an x-ray controller (not shown) through the ceiling to video display18. Power for the cine recorder is provided by cable21. Typically, x-ray source14is activated to one of two different intensity levels, respectively referred to as the fluoroscopy and cine modes, such that the cine mode has an intensity level four times greater than that of the fluoroscopy mode. Control console22for the movement of table11as well as for x-ray source14is fixedly mounted on one end of operating table11.

In a typical operating room, one or more lead impregnated plastic, optically transparent vertically extending x-ray shield panel(s)24is located in proximity to proximate side23of table11. Each shield panel24is mounted on bracing structure25, on which are mounted casters26for enabling the shield panel to be easily moved relative to platform12on floor13. Shield panel24extends from about a foot above floor13to about 6½ feet above the floor and for about 3 feet from side to side so the entire body of a surgeon standing behind the panel is effectively shielded from x-rays back-scattered from table11and the patient lying on the table.

One or more additional shield panels30(only one of which is included inFIG. 1for clarity) somewhat similar to shield panel24are usually included, such that one additional shield panel30is provided for each assistant to the operator who is standing next to table11. Additional shield panel30does not include controllers for the movement of table11that are included on panel24.

In the prior art, the additional panel30is a planar, structure that is mounted on casters. Panel30of the prior art does not enable the person standing behind the panel to assist the surgeon who is standing behind panel24while x-ray source14is activated, unless such a person is willing to step around panel30and risk x-ray exposure.

Hence, during the cine operation, while x-ray source15is activated, body parts of the persons who should be standing behind prior art panel30are irradiated by x-ray radiation back-scattered from the patient and table11. Over a prolonged period of many years, such a person is likely to be subjected to considerable amounts of x-ray radiation back-scattered from the table and patients on which the cardiac catheterization procedure has been performed. The accumulated effects of the back-scattered radiation on the persons may lead to the persons becoming cancer victims.

As a result of the present invention, the prior art panel30is modified so persons standing behind an x-ray shield panel located around table11can participate with his/her hands in the procedure while x-ray source14is activated. The modified panel is such that one or both hands and forearms are the only parts of the person exposed to the back-scattered x-ray radiation. Exposure to x-rays by one or both hands and forearms is much less likely to result in cancer than exposure to x-rays by other body parts.

Reference is now made toFIGS. 2-6of the drawing, illustrations of a first embodiment of a shield panel that can be placed where shield panel30is illustrated inFIG. 1. The shield panel ofFIGS. 2-6includes base32, center leg34and exterior legs36-39, fixedly connected to leg34and arranged so that legs36and37extend in opposite directions from one end of center leg34and legs38,39extend in opposite directions from the other end of center leg34. Opposite ends of legs36-39carry casters42that enable the shield panel ofFIGS. 2-6to be easily moved around the operating room.

Rectangular, x-ray shield panel44is fixedly mounted on and aligned with center leg34so panel44extends from the center leg upwardly in the vertical plane. The periphery of panel44is circumscribed by metal frame46, having a vertically extending edge48that is substantially aligned with legs38and39and carries piano hinge50. The upper portion of hinge50is attached to frame52that circumscribes upper x-ray shield panel54. The lower part of hinge50is attached to a vertically extending edge of frame56that circumscribes lower x-ray shield panel58that can be considered as a lower x-ray shield panel arrangement.

Typically, x-ray shield panels44,54and58are plastic panels embedded with lead so that they have a 1.0 or 2.0 mm lead equivalent, causing the plastic panels to be 22 or 46 mm thick. Frames52and56are hung on hinge50such that there is a gap60between the upper edge of frame56and the lower edge of frame52. Because x-ray shield panels54and58extend within frames52and56virtually to the opposite sides of gap60, gap60can be considered as the gap between the lower edge of shield panel54and the upper edge of shield panel58. In a typical embodiment, gap60has a vertical extent, i.e., height, of ¾ inch. The thicknesses of panels54and58and the vertical length of gap60are such that back-scattered x-rays incident on the front face of panel54, the front face of panel58and gap60are substantially attenuated and are not harmful to a person standing behind panels54and58, when the panels are aligned in a plane, such that the front faces of the panels are approximately 2 inches from proximate edge23of operating table11.

Upper shield panel54and lower shield panel58are dimensioned to cause a person standing behind panels54and58to be protected from back-scattered radiation from the patient being operated on and/or from table11. To this end, in one embodiment panels54and58respectively have heights of 28½ and 44 inches, so that the total height of panels54and58and gap60is 73¼ inches, the same height as panel44. Panels54and58have the same length in the horizontal plane of 24 inches while panel44has a length in the horizontal place of 30 inches. These dimensions are such that when panels54and58are aligned, panel54protects the head, upper torso, part of the midsection and arms and legs of the person, while panel58protects the remainder of the midsection, lower torso, legs and feet of the person. It is to be understood that the aforementioned dimensions are the preferred dimensions, but can be changed, as necessary, depending upon the height and girth of the person standing behind panels54and58.

Panel54is transparent to visible optical energy, so that the person standing behind panels54and58can see what is happening on operating table11and participate in the operation, as necessary. Panels44and58can be transparent or opaque to visible optical energy, as desired.

In use, panel44is located at right angles to proximate edge23of operating table11, so that one face of panel44abuts or is in very close proximity to an edge of panel24. Panel58is positioned so that the front planar surface thereof is parallel to spaced approximately 2 inches from proximate23edge of operating table11. When the person standing behind panels54and58is only observing what is happening on operating table11, panel54is aligned with panel58, so that both panels54and58are parallel to and approximately 2 inches from proximate edge23of operating table11.

When the person standing behind panels54and58needs to participate in the operation, panel54is turned about hinge50to such an extent that the person standing behind panels54and58can place one or both of its hands and one or both of its forearms through the opening between panels54and58created by panel54being turned toward the proximate edge23of operating table11. Preferably, the height of table11is adjusted so the lower edge of panel54lies on a body part of the patient on operating table11, typically the legs of the patient, to minimize radiation back-scattered from the patient and/or table11through the opening resulting from panel54being turned about hinge50. If necessary, panel54can be turned 90 degrees relative to panel58, so that panels44and54are both at right angles to the proximate edge23of operating table11. If necessary or desirable, panel58is turned about hinge50so that the vertical edge of panel58that is remote from hinge50contacts proximate edge23of operating table11.

According to a modification of the shield arrangement ofFIGS. 2-6, the upper shield panel and lower shield panel arrangement are such that the lower edge of the upper shield panel can always be turned so that it contacts the body of the patient and the gap between the lower edge of the upper shield panel and the upper edge of the lower shield arrangement is maintained constant. Such a modification is illustrated inFIGS. 7-9.

In the embodiment ofFIGS. 7-9, base32and casters42are identical to the arrangement ofFIGS. 2-6. In the embodiment ofFIGS. 7-9, shield panel68is similar, but slightly different from panel44, but upper shield panel70is identical to upper shield panel54of the embodiment ofFIGS. 2-6. However, mounting of upper shield panel70is quite different from mounting of shield panel54.

Lower shield panel arrangement72in the embodiment ofFIGS. 7-9includes a first, upper panel74and a second, lower panel76. Panel74is mounted relative to panel70so that the upper edge of panel74and the lower edge of panel70have a ¾ inch constant height gap78between them, despite the fact that panels70and74can be raised together and the lower edge of panel70can be swung outwardly to engage an upper surface of the body of the patient, such as the top of the patient's legs. Panel76is fixedly mounted so that the bottom edge thereof abuts or is slightly above the operating room floor on which casters42rest. Panels74and76are dimensioned and mounted so that the upper edge of panel76is always above the lower edge of panel74and the back planar face of panel74and the front planar face of panel76always remain parallel and in close proximity to each other, so that the person standing behind panels70,74and76is shielded from back-scattered x-rays incident on the front face of panel74. When panels70,74and76are parallel to each other, panel70protects the head, upper torso, arms and hands of the person, panel74protects the midsection and the upper and middle leg portions of the person and panel76protects the middle and lower leg portions and feet of the person.

In one preferred embodiment, panels68,70,74and76have the same thickness of 22 or 46 mm. Panel68has a height of 73¼ inches and a width of 32 inches between its vertical edges; each of panels70,74and76has a width of 30 inches between its vertical edges; panel70has a height of 28½ inches; panel74has a height of 34 inches and panel76has a height of 26 inches; and the gap between the top edge of panel76and the bottom edge of panel74is ¾ inch. Such dimensions provide the required protection for most persons who stand behind panels70,74and76.

Panels70,74and76are coupled to panel68and panel68is constricted in such a manner that front edge77of panel68extends to the proximate edge23of table11when the front, planar faces of panels70,74and76are parallel to and spaced from the proximate edge23of table11by a distance of 2 inches. Because of the abutting relationship of front edge77of panel68with the proximate edge23of table11, the amount of back-scattered radiation from the table and patient that is incident on the person standing behind panels70,74and76is substantially reduced.

The structure80for coupling panels70,74and76to panel68includes rod or tube82that is fixedly connected to the top of panel68and includes leg83that extends upwardly from the top edge of panel68by a suitable distance, e.g., 1 foot. The connection point of tube82to the top edge of panel68is horizontally aligned with panels70,74and76when panels70,74and76are positioned so that the front faces thereof are parallel to proximate edge23of table11, i.e., the base of tube82is 2 inches from the edge of panel68that abuts the proximate edge23of table11. Tube82has a right angle bend 12 inches above the top edge of panel68, to form leg85that extends horizontally in a plane aligned with panels70,74and76. The horizontal extent of leg85is 2 inches, to another right angle bend, at which tube82extends downwardly in the vertical plane to form leg87. Leg87extends downwardly to a point aligned with base32, where tube82has a further right angle bend to form leg89that extends horizontally in a plane aligned with the plane of panels74and76. The end of leg89remote from panels76and78is fixedly connected to base82. Tube82thus forms a rigid structure that ultimately carries panels70,74and76so panel70can turn about a vertical axis defined by the axis of leg87. Panels74and76are mounted so they stay in planes substantially parallel to proximate edge23of table11.

To enable panels70and74to be raised and lowered together and to enable panel70to be turned about the vertical axis of leg87while panels74and76remain parallel to edge23, panels70and74are respectively fixedly mounted on sleeves90and92that are concentric with and slidable relative to the length of long leg87of tube82. The bottom portion of sleeve90is connected to the top portion of sleeve92by flexible coupling93that enables sleeve90to turn about leg87relative to sleeve92while maintaining a constant vertical separation of ¾ inch between the bottom edge of sleeve90and the top edge of sleeve92. To this end, the bottom portion of sleeve90is fixedly connected to the top portion of flexible coupling93and the top portion of sleeve92is fixedly connected to the bottom portion of coupling93. Coupling93has sufficient lengthwise stiffness, i.e., stiffness in the vertical direction, to maintain the distance between the lower edge of panel70and the upper edge of panel74constant, even though the coupling is turned through an angle about its longitudinal axis in excess of 90°. As described infra, panel76remains in situ while panels90and92are moved up and down together and panel70is turned relative to panels74and76. Sleeves90and92are connected to the proximate edges of panels70and74by clamps95and96, respectively. Clamp96rigidly and fixedly holds panel74to sleeve92, while clamp95is arranged so that one end thereof is fixedly connected to panel70and the other end is selectively fastened and released from sleeve90. Clamp95is released from sleeve90while panel70is turned about leg87of rod82. When panel70has been turned to the desired angle about leg87, clamp95is fastened to sleeve90so panel70remains at the desired angular position relative to leg87; for example, panel70can be turned so that at a first position panels70and74are aligned and at a second position, panel70is turned 90° relative to panel74so the faces of panels68and70are in parallel planes.

Pulley system102that includes metal pulley cable100enables panels70and74to be raised and lowered together so that gap78between the upper edge of panel74and the lower edge of panel70remains constant. Opposite ends of pulley cable100are connected to the top edge of panel70and counterweight106so that panels70and76are raised and lowered by moving pulley cable100up and down. Pulley system102also includes pulley wheel assembly104, mounted on by swivel103horizontally extending leg105that is aligned with leg85of rod82, so that assembly104is free to turn as panel70turns. Pulley wheel assembly104comprises pulley wheel108having a circumferential groove about which cable100is wound and a cable brake (not shown). The cable brake of pulley wheel assembly104is applied when the bottom edge of panel70is at the desired position, i.e., at a position so that the bottom edge of panel70contacts the body of the person being operated on. Adjustment of the height of the bottom edge of panel70is easily provided in a precise manner by appropriate selection of the weight of counterweight102, so that the counterweight and the combined weights of panels70and74, that can exceed 1,000 pounds, are closely matched.

Rack110, fixedly mounted to rod82by pins112, maintains panels74and76in planes parallel to each other and parallel to the proximate edge23of operating table11. Rack110enables panel74to be driven up and down by cable82, but holds panel76firmly in place. Rack110has a height less than the minimum height of the upper edge of panel74above the operating room floor so that a portion of panel74always extends above the upper edge of rack110.

Rack110includes base116that is fixedly positioned slightly above the operating room floor when the shield arrangement ofFIGS. 7-9is in place. The bottom edge of panel76rests on base116, and the side edges of panel76are fixedly captured by interior surfaces of vertically extending channels118and120(FIG. 9), such that flanges122of channels118and120capture the front and back faces of panel76, and the interior surfaces of the elongated, vertically extending bases126of channels118and120capture the opposite vertically extending edges of panel76.

Rack110also includes channels128and130that hold panel74in place. Channels128and130include flanges132that capture the front and back faces of panel74, as well as elongated, vertically extending bases134that capture the opposite edges of panel74. The interior flanges124and132of channels118,120,128and130have abutting faces that are welded together so that rack110is formed as a unitary structure in which panel76is maintained at a fixed, constant position, while panel74is free to move up and down relative to panel76, but panel74can not turn appreciably relative to panel76due to the way panel74fits in channels128and130.

Prior to an operation on a patient commencing, the surgeon adjusts the height of table11above the operating room floor so that the patient is located at a position where the surgeon is comfortable while operating on the patient. Then, the shield assembly ofFIGS. 7-9is wheeled into place so that the forward edge77of panel68abuts the proximate edge23of operating table11, while panels70,74and76are locked in place at a position, such that (1) the front faces of panels70,74and76are parallel to the proximate edge23of operating table11, and (2) the upper edge of panel74and the lower edge of panel70are above the legs of the person being operated on. Hence, clamp95is fixedly connected to sleeve90and the brake of pulley wheel assembly104is engaged at this time. Then, clamp95is released and sleeve90is turned about leg87of cable82, so that panel70extends above the patient on the operating table. Then, clamp95is locked to sleeve90, so that flexible coupling93is twisted through an angle equal to the angular displacement of panel70from panel74. Then, the brake of pulley wheel assembly104is released and leg87of cable82is pulled downwardly until the bottom edge of panel70rests on the legs of the person being operated on. Then, the brake of pulley wheel assembly104is activated, to lock cable100at a fixed vertical position, so that the fixed vertical positions of panels70and74are locked. Then, clamp95is released and panel70is turned about leg87of tube82, so that the front face of panel70is parallel to proximate edge23of operating table11. If the person standing behind panels70,74and76is required to participate in the operation, clamp95is released and panel70is turned toward operating table11, about leg87of tube82, until panel70is at the required angle. Then, clamp95is tightened, so that panel70is maintained at the desired angle, to provide an opening through which the hand or hands and forearm or forearms of the person standing behind panels70,74and76can extend to enable such a person to participate in the operation. Flexible coupling93is then twisted through an angle equal to the angular displacement of panel70from panel74. When it is desired to re-align panels70and74or upon completion of the operation, the foregoing steps are reversed.

While a specific embodiment of the invention has been described and illustrated, variations regarding details of the embodiments specifically illustrated and described may be made without departing from the true spirit and scope of the invention as defined in the appended claims. For example, standard controllers, as well as the controllers described in my aforementioned patent, can be mounted on the panels of both embodiments, if necessary or appropriate. In addition, the spacing between the bottom edge of panel54and the top edge of panel58and the spacing between the bottom edge of panel70and the top edge of panel74can be any suitable distance less than ¾ inch, as long is there is sufficient spacing between these edges to enable the upper panel to turn relative to the lower panel.