SPECIFICATION CROSS-REFERENCE TO RELATED APPLICATIONS This PCT application claims the benefit under 35 U.S.C. § 1 19(e) of United States Patent Application Serial No. 62/186,700, filed June 30, 2015, entitled CLAMP ASSEMBLY FOR PATIENT POSITIONING SYSTEM AND PATIENT POSITIONING SYSTEM INCLUDING THE SAME, the disclosure of which is incorporated by reference herein.

FIELD OF THE INVENTION

This invention relates generally to rail assemblies for use in patient positioning systems and more particularly to rail assemblies including clamp assemblies configured to be connected to multiple types of patient support panels or couch-tops.

BACKGROUND OF THE INVENTION

Stereotactic body radiotherapy (SBRT) is a rapidly developing area of cancer management. Patients undergoing SBRT typically are disposed on a treatment couch or table associated with a LINAC or other the radiation therapy apparatus. Moreover, it is a common practice to position and fix a portion of the patient so that repeated treatment can be given to the patient. To that end, some indexing system is provided for mounting various types of patient positioning and/or fixation devices on a couch-top or overlay at a desired position. Examples of such patient positioning/fixation devices are head and neck positioning/fixation devices, breast and thorax positioning/fixation devices, and hip and pelvic region positioning/fixation devices. Many of such devices, as well as other miscellaneous positioning aids, e.g., cushions, wedges, etc., for use on the treatment couch-top are available from Civco Medical Products, Inc. (hereinafter "CIVCO"), and are shown in its "Radiation Oncology Sourcebook" ©2007.

Treatment couch-tops/overlays are also available from CIVCO and other manufacturers, such as Sinmed B.V, Varian Medical Systems, Inc., Elekta AB, and others. Those couch-tops are configured for disposition on a CT table for scanning the patient and on a treatment table of a LINAC or other radiation therapy beam apparatus repeatedly position/fix any portion of the body of the patient at any desired position(s) for SBRT or any other procedure requiring repeated immobilization of that portion(s) of patient's body.

Many prior art couch-tops make use of an array of equidistantly spaced indexing points running down the side of the couch-top/overlay to which patient positioning/fixation devices can be secured. For example, CIVCO offers a two-pin LOK-BAR™ device that is configured to be connected to the couch-top/overlay at any of the indexing points. The two-pin LOK-BAR™ device is an elongated bar that includes two pins projecting upward for receipt in corresponding holes on CIVCO 's line of patient positioning and fixation devices. To index a particular positioning/fixation device to the couchtop or overlay the LOK-BAR™ device is attached to the couch-top or overlay via any of the multiple indexing points. The particular patient positioning/fixation device is then mounted on the LOK-BAR™ device by disposing it on the LOK-BAR™ device so that the two-pins of the LOK- BAR™ device are received within corresponding apertures in the positioning/fixation device. By indexing the patient positioning/fixation device(s) to the same indexing points for every radiation treatment one can be assured of increased target accuracy and patient throughput.

CIVCO also offers a rail assembly for releasable mounting onto a couch-top or overlay. The CIVCO rail assembly basically comprises a pair of elongated, linear side rails, each of which includes a plurality of indexing recesses along the length thereof. The rails extend along and parallel to the sides of the couch-top for releasably mounting some patient positioning/patient fixation device(s) on the rails. The rail assembly includes plural clamp mechanisms to releasably secure the rail assembly to the couch-top. Those clamp assemblies are particularly constructed for the particular couch-top to which the rail assembly will be mounted.

Varian Medical Systems, Inc. offers two types of couch-tops under the trademark VARIAN EXACT. One such VARIAN EXACT couch-top is for CT applications and includes a pair of linear side edges, each of which is planar. Another VARIAN EXACT couch-top is for IGRT applications and includes a pair of linear side edges, each of which is arcuate or curved. Both of those VARIAN EXACT couch-tops include a plurality of indexing recesses along the side edges thereof.

At present there is no patient positioning system in the form of a rail assembly including a clamp mechanism which is suitable for mounting on both types of VARIAN EXACT couch-tops, or other couch-tops having dissimilar side edges but including indexing recesses, that robustly resists upward forces or loading while maintaining the attachment. Thus, a need exists for such a rail assembly. The subject invention addresses that need. In addition, the subject invention provides a clamping mechanism that can form a portion of other components, e.g., an overlay, or any other device, for releasable securement on both types of VARIAN EXACT couch-tops, or other couch-tops having dissimilar side edges but including indexing recesses.

All references cited and/or identified herein are specifically incorporated by reference herein.

SUMMARY OF THE INVENTION

In accordance with one aspect of the invention there is provided a clamp assembly for releasably mounting a component to a first patient support panel and to a second patient support panel. The first patient support panel is a generally planar member having pair of longitudinally extending, e.g., linear, side edges of a first cross-sectional shape, e.g., in the form of a planar edge surface. The second patient support panel is a generally planar member having pair of longitudinally extending, e.g., linear, side edges of a second cross-sectional shape, e.g., in the form of an arcuate edge surface. The second cross-sectional shape is different than the first cross-sectional shape. The clamp assembly comprises a first pivotable jaw and a second pivotable jaw. The first pivotable jaw is configured to be pivoted about a pivot axis between an unlocked position and a locked position, and vice versa. The first pivotable jaw has a surface engaging one of the side edges of the first patient support panel when pivoted to the locked position to releasably secure the clamp assembly thereto. The second pivotable jaw has a first portion cooperating with a first surface of the component or a first surface of the clamp assembly to assist in holding the first pivotable jaw in the locked position. The second pivotable jaw is configured to be pivoted about a pivot axis between an unlocked position and a locked position, and vice versa. The second pivotable jaw has a surface engaging one of the side edges of the second patient support panel when pivoted to the locked position to releasably secure the clamp assembly thereto. The second pivotable jaw has a second portion cooperating with a second surface of the clamp assembly to assist in holding the second pivotable jaw in the locked position. In accordance with one preferred embodiment of a clamp assembly of this invention it is configured to enable the independent adjustment of the first and second pivotable jaws and the first and second pivotable jaws are configured to pivot as a unit about a common pivot axis. The clamp assembly comprises a slide member and a clip member. The slide member serves to mount the first and second pivotable jaws on it for rotation about the pivot axis and is configured to slide between an open position and a closed position, and vice versa. The pivotable jaws are enabled to assume the unlocked position when the slide member is in the open position and to assume the locked position when the slide member is in the closed position. The clip member is coupled to the slide member and configured to selectively enable and disable the slide member from sliding.

The component to which the clamp assembly of this invention is mounted can take various forms, e.g., a rail assembly, an overlay, or any other device which is desired to be mounted onto dissimilarly shaped couch-tops.

In accordance with another aspect of this invention there is provided a patient positioning system for selective releasable securement to a first patient support panel and to a second patient support panel. The first patient support panel is a generally planar member having a pair of longitudinally extending, e.g., linear, side edges, with each of the side edges of the first patient support panel being of a first cross-sectional shape, e.g., in the form of a planar edge surface. The second patient support panel is a generally planar member having pair of longitudinally extending, e.g., linear, side edges, with each of the side edges of the second patient support panel being of a second cross-sectional shape, e.g., in the form of an arcuate edge surface. The second cross-sectional shape is different than the first cross- sectional shape.

One exemplary preferred embodiment of the patient positioning system comprises a rail assembly another exemplary preferred embodiment of the patient positioning system comprises an overlay. Those two patient positioning systems are merely exemplary of various types of patient positioning systems to which the subject invention is directed.

The rail assembly comprises a pair of elongated side rails, at least one cross- member and plural clamp assemblies. The at least one cross-member is an elongated member having a pair of end portions. Each of the end portions includes a respective clamp assembly mounted thereon and is secured to a respective one of the side rails. Each of the clamp assemblies comprises a first pivotable jaw and a second pivotable jaw. The first pivotable jaw is configured to be pivoted about a pivot axis between an unlocked position and a locked position, and vice versa. The first pivotable jaw has a surface configured for engaging one of the side edges of the first patient support panel when pivoted to the locked position to releasably secure the clamp assembly thereto. The second pivotable jaw has a first portion cooperating with a first surface of the component or a first surface of the clamp assembly to assist in holding the first pivotable jaw in the locked position. The second pivotable jaw is configured to be pivoted about a pivot axis between an unlocked position and a locked position, and vice versa. The second pivotable jaw has a surface configured for engaging one of the side edges of the second patient support panel when pivoted to the locked position to releasably secure the clamp assembly thereto. The second pivotable jaw has a second portion cooperating with a second surface of the clamp assembly to assist in holding the second pivotable jaw in the locked position.

The overlay comprises a generally planar panel having a pair of side edges, each of the side edges includes at least one recess. Each recess is configured to accommodate a portion of an associated clamp assembly therein. Each of the clamp assemblies comprises a first pivotable jaw and a second pivotable jaw. The first pivotable jaw is configured to be pivoted about a pivot axis between an unlocked position and a locked position, and vice versa. The first pivotable jaw has a surface configured for engaging one of the side edges of the first patient support panel when pivoted to the locked position to releasably secure the clamp assembly thereto. The second pivotable jaw has a first portion cooperating with a first surface of the overlay or a first surface of the clamp assembly to assist in holding the first pivotable jaw in the locked position. The second pivotable jaw is configured to be pivoted about a pivot axis between an unlocked position and a locked position, and vice versa. The second pivotable jaw has a surface configured for engaging one of the side edges of the second patient support panel when pivoted to the locked position to releasably secure the clamp assembly thereto. The second pivotable jaw has a second portion cooperating with a second surface of the clamp assembly to assist in holding the second pivotable jaw in the locked position.

In accordance with one preferred embodiment of the patient positioning system invention, the clamp assembly of that system is configured to enable the independent adjustment of the first and second pivotable jaws and the first and second pivotable jaws are configured to pivot as a unit about a common pivot axis. Each of the clamp assemblies comprises a slide member and a clip member. The slide member serves to mount the first and second pivotable jaws on it for rotation about the pivot axis and is configured to slide between an open position and a closed position, and vice versa. The pivotable jaws are enabled to assume the unlocked position when the slide member is in the open position and to assume the locked position when the slide member is in the closed position. The clip member is coupled to the slide member and configured to selectively enable and disable the slide member from sliding.

DESCRIPTION OF THE DRAWING

Fig. 1 is an isometric view of one exemplary embodiment of an exemplary patient positioning system constructed in accordance with this invention, e.g., a rail assembly having plural clamp assemblies releasably securing the rail assembly to a patient support panel or couch-top, with the clamp assembly being configured to accommodate patient support panels/couch-tops having differing shapes;

Fig. 2 is an isometric view of a conventional two pin locking bar that can be used with the patient positioning system shown in Fig. 1 ;

Fig. 3 is an enlarged isometric view of a portion of the rail assembly shown within the broken circle identified by the reference number 3/5 of Fig. 1 , but with the clamp assembly of that portion of the rail assembly hidden;

Fig. 4 is an isometric view of one end of a cross-bar forming a portion of the rail assembly shown in Fig. 3;

Fig. 5 is an isometric view similar to Fig. 3, showing the clamp assembly that was hidden in Fig. 3, but with other portions of the rail assembly, e.g., a mounting bracket and side rail, hidden;

Fig. 6 is an exploded isometric view of the various components making up one of the plural clamp assemblies of the patient positioning system shown in Fig. 1 ;

Fig. 7 is a top-side oblique isometric view of one portion of the patient positioning system of Fig. 1 showing a pivotable jaw of one of its clamp assemblies in releasable engagement with a planar side edge of a conventional CT couch-top to releasably secure that portion of the rail assembly to that portion of the couch-top;

Fig. 8 is another top-side oblique isometric view of the portion of the patient positioning system shown in Fig. 7, but with portions of the rail assembly, e.g., its mounting bracket and its associated side rail, hidden; Fig. 9 is a bottom-side oblique isometric view of the portion of the patient positioning system shown in Fig. 7;

Fig. 10 is an isometric view similar to Fig. 8, but showing a spring lock clip forming a portion of the clamp assembly in the process of being flexed to enable the clamp assembly to be slid open to release the clamp assembly from engagement with the side edge of the CT couch-top;

Fig. 1 1 is an isometric view similar to Fig. 7, but showing the clamp assembly after it has been slid to its open position wherein it is no longer in releasable engagement with the side edge of the CT couch-top;

Fig. 12 is an isometric view, similar to Fig. 1 1, but showing another pivotable jaw of the clamp assembly in its open position so that it is readied for releasable engagement with a curved side edge of a conventional IGRT couch-top to mount the rail assembly on that type of couch-top;

Fig. 13 is an isometric view similar to Fig. 12 showing that other pivotable jaw in its closed or locked position wherein it is in releasable engagement with a curved side edge of that couch-top;

Fig. 14 is a bottom-side oblique isometric view of the portion of the patient positioning system shown in Fig. 13 ;

Fig. 15 is a side elevation view of the portion of the patient positioning system shown in Figs. 13 and 14, wherein the clamp assembly is in its locked position in releasable engagement with the curved side edge of the IGRT couch-top;

Fig. 16 is an exploded isometric view of one of plural locators forming a portion of the rail assembly shown in Fig. 1 ;

Fig. 17 is an isometric view, partially in section, of the clamp assembly in its locked state releasably secured to a CT couch-top like shown in Figs. 7 - 9;

Fig. 18 is an isometric view, partially in section, of the clamp assembly in its locked state releasably secured to an IGRT couch-top like shown in Figs. 13 - 15.

Fig. 19 is an isometric view, similar to Fig. 1 , of another exemplary embodiment of an exemplary patient positioning system, e.g., an overlay having plural clamp assemblies releasably securing the overlay to a patient support panel or couch-top, with the clamp assemblies being configured to accommodate patient support panels/couch-tops having differing shapes;

Fig. 20 is an exploded isometric view of a portion of the overlay shown in

Fig. 1 ; Fig. 21 is another exploded isometric view of the portion of the overlay shown in Fig. 19, but taken from a different angle, i.e., the underside of the overlay; and

Fig. 22 is an isometric view, partially in section, of the clamp assembly of the overlay of Fig. 19 shown in its locked state releasably securing the overlay to a CT couch-top, like that shown in Fig. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the various figures of the drawing wherein like reference characters refer to like parts, there is shown in Fig. 1 one exemplary embodiment of patient positioning system 20 constructed in accordance with this invention. Fig. 1 shows another exemplary embodiment 120 of a patient positioning system constructed in accordance with this invention. Those two patient positioning systems will be described in detail later. Suffice it for now to state that they are merely exemplary of various types of patient positioning systems to which the subject invention is directed.

As can be seen in Fig. 1 , the patient positioning system 20 basically comprises a rail assembly 22 and at least one locking bar 24 (Fig. 2). The at least one locking bar is constructed similarly to the heretofore identified LOK-BAR ^rM device and is arranged for releasably mounting on the rail assembly 22 to releasably mount some patient positioning/fixation component (not shown) thereon. The rail assembly 22 is itself arranged to be releasably secured to a couch-top or other patient support panel, such as an overlay, to mount it on the couch-top/patient support panel. As mentioned above, in accordance with one aspect of this invention the rail assembly 22 includes plural clamp assemblies which enable the rail assembly to be releasably mounted on conventional CT couch-tops as well as on conventional image guided radiation therapy (IGRT) couch-tops, such as those discussed above. To that end, each clamp assembly includes two pivotable jaws, each of which is configured to be moved, e.g., pivoted, from an unlocked or open position to a locked or closed position, and vice versa. When a jaw is in its unlocked position, it is spaced from the side edge of the couch-top, whereas when a jaw in its locked position it is in engagement with the side edge of the couch-top, thereby releasably securing the clamp assembly (and hence the rail assembly) to the couch- top. Thus, with the rail assembly mounted on the couch-top one can repeatedly position/fix any portion of the body of a patient at any desired position(s) for SBRT or any other procedure requiring repeated immobilization of that portion(s) of patient's body.

As will be appreciated by those skilled in the art from the discussion to follow, the exemplary preferred embodiment of the patient positioning system 20 shown and described hereinafter is particularly configured for use with VARIAN EXACT couch-tops, whether in the form of a CT patient support panel 2A, like shown in Figs. 1 , 3, 5 and 7 - 1 1 or in the form of an IGRT patient support panel 2B, like shown in Figs. 12 - 15. It should be noted that other vendors provide similar types of couch-tops. For example, a CT patient support panel, like panel 2A, is also available from CIVCO.

Each of the exemplary patient support panels 2A and 2B comprises a generally planar member which is of sufficient size to support an adult patient in a prone or supine position. Moreover both patient support panels have a pair of longitudinally extending linear side edges. In particular, the CT patient support panel or couch-top 2A basically comprises an elongated planar member having a pair of longitudinally extending side edges 10 which are generally planar, e.g., the couch- top is of rectangular cross-section. The IGRT patient support panel or couch-top 2B also basically comprises an elongated generally planar member, except that it has a pair of longitudinally extending curved side edges 12. The side edges of both of the patient support panels 2 A and 2B include plural indexing recesses 14 (Fig. 1) equidistantly spaced along the length thereof. As best seen in Figs. 7 - 14, each of the indexing recesses 14 is of semi-circular shape, with a generally planar bottom surface 14A.

As will be described in detail later, the rail assembly 22 includes plural indexing locators for releasable receipt within the indexing recesses 14 to locate the rail assembly 22 with respect to the couch-top at a desired longitudinal position therealong. It must be pointed out at this juncture that the patient positioning system 20 and its rail assembly 22 can be readily configured for use on other couch-tops or patient support panels in lieu of the VARIAN EXACT couch-tops shown.

As can be seen in Fig. 2, the locking bar 24 is of conventional construction and is arranged to be releasably secured at any one of plural indexing positions along the length of the rail assembly 22 when the rail assembly is mounted on the couch-top 2 A or on the couch-top 2B. In particular, the locking bar 24 is configured for mounting between a pair of elongated side rails 26, which make up a portion of the rail assembly 22. Each side rail 26 is an elongated linear tubular member of circular cross section and includes a plurality of indexing recesses or apertures 28 (Figs. 1 , 3, 7 and 1 1 - 13) equidistantly spaced along the length thereof. The indexing recesses 28 of the two side rails 26 are arranged in longitudinally aligned pairs for receipt of respective downwardly projecting releasably securable pins 24A located at respective ends of the locking bars 24. Thus, the locking bar 24 can be releasably secured at any desired longitudinal index position along the pair of side rails. The locking bar 24 is an elongated generally planar linear member having a central section 24B having a pair of upwardly projecting curved extensions 24C located at the respective opposite ends of the central section. The heretofore identified downwardly projecting releasably securable pins 24A are disposed at respective extensions 24C. Thus, when the locking bar 24 is mounted on the side rails 26 of the rail assembly by the insertion of the pins 24A in the indexing recesses 28 of those rails, the central section 24B of the locking bar will be located below the side rails and close to the top surface of the couch-top 2 A or 2B. The central section 24B of the locking bar includes two or three upwardly projecting registration pins 24D for enabling the releasable mounting of conventional positioning and immobilizing (fixation) devices or other components, e.g., vacuum bags, knee rests, foot supports, head supports, etc., (not shown) to the locking bars and hence to the couch-top on which the rail assembly 22 is mounted. As mentioned above such positioning/fixation components are available from a number of vendors, including CIVCO.

It should be pointed out that the pair of side rails 26 can also serve to releasably mount one or more modular patient fixation or positioning components thereon, e.g., bridge members, such as shown in United States Letters Patent 8,905,035 (Wilson et al.), and 8, 146,599 (Wilson et al.), and U.S. Patent Application S.N. 14/570,434, filed on December 15, 2014 and entitled Bridge Device For Patient Positioning System, which are assigned to the same assignee as this invention.

Turning now to Figs. 1 , 3 - 5, the details of the rail assembly 22 will be described. Thus, as can be seen, the rail assembly basically comprises the heretofore identified pair of side rails 26, two cross bars 30, four brackets 32, four indexing locators 34 and four clamp assemblies 36. Each cross bar 30 is an elongated generally planar member having a pair of end portions 38, each of which includes a recess 40 (Figs. 3 and 4) therein. Each recess 40 is arranged to accommodate a portion of an associated clamp assembly 36 therein and each includes an inclined ledge surface 40A (to be described later) configured to be engaged by a portion of the associated clamp assembly to hold the clamp assembly in its locked position. Moreover, each end portion 38 of each cross bar 30 includes a respective bracket 32 fixedly mounted thereon to connect the associated side rail to the cross-bar. In particular, each bracket is connected to a respective end portion of its associated cross bar 30 via plural screws 42 (Figs. 8 and 10) extending through respective holes 30A (Fig. 4) located in the cross-bar immediately adjacent the recess 40. As mentioned above, the brackets 32 serve to mount the pair of side rails 26 onto the cross-bars. To that end, each bracket 32 includes an elongated concave recess 44 (Fig. 15) extending transversely across the face of the bracket. Each recess 44 is configured to receive a respective peripheral portion an associated side rail 26. The side rail is fixedly secured within the recess 44 via plural screws 46 (Figs. 7, 9 and 1 1 - 15).

The longitudinal positioning of the rail assembly 22 with respect to the couch-top 2A or 2B is achieved by means of the indexing locators 34, while the releasable securement of the rail assembly at that longitudinal position is achieved by means of the clamp assemblies 36. The details of the construction and operation of the indexing locators 34 and the clamp assemblies 36 will be described later. Suffice it for now to state that each of the indexing locators 34 comprises a pair disks and an associated screw. Each locator is arranged to be releasably located in any one of the indexing recesses 14 in the side edges of the couch-top 2 A or 2B to generally locate the rail assembly at a desired longitudinal position along the couch- top. Then the clamp assemblies 26 can be operated independently to releasably fix the rail assembly at the desired location without interference from the indexing discs.

Turning now to Fig. 16, the details of each locator 34 will now be described. To that end, each locator 34 comprises a pair of disks 48 and 50 and a screw 52. The disks 48 and 50 are connected to a respective end portion 38 of an associated crossbar 30. In particular, each cross bar includes a countersunk hole 30B (Figs. 3 and 4) located adjacent the recess 40 and which is configured to receive the screw 52. The screw 52 serves to fixedly secure the disks 48 and 52 to the cross-bar. The disk 48 is of a generally pin-wheel shape having plural resilient fingers 48A projecting outward from the central portion of the disk. A hole 48B is located in the center of the disk 48. The disk 50 is a locating disk having a solid body including an upwardly projecting central hub 50A, with a threaded hole 50B extending into the hub. The hub is disposed within the hole 48B in the disk 48 to stack the disks together. The threaded end of the screw 52 which extends through the hole 30B in the cross-bar 30 is threadedly engaged within the hole 50B to fixedly secure the stacked disks underneath the end 38 of the cross-bar 30. The outer diameter of the disk 50 is slightly less than the inside diameter of the semi-circular recess 14, so that it can be received within that recess with some "give", i.e., it can be moved in any radial direction with respect to the recess. The outer diameter of the disk 48, i.e., the outermost surfaces of the fingers 48A, is slightly greater than the inner diameter of the recesses 14. Thus, when the locator 34 is located within a recess 14, with the undersurface of the disk 50 disposed on the bottom 14A of the recess, the fingers 48A of the pin-wheel shaped disk 48 can flex so that the locator can be moved within the recess in any radial direction. This feature is important in that it enables the locator to absorb small tolerance variation in the location of the recesses 14. In particular, as should be appreciated by those skilled in the art, the small flexibility of the indexing disks 48 enables the absorption of small tolerance variations in indexing recesses 14 to provide reasonably precise longitudinal positioning while minimizing the possibility of a binding occurrence between the locating disks 50 and those recesses. Moreover, the "give" provided by the locator, enables the user of the rail assembly to fix a balanced tension of each clamp assembly without excessive binding in the indexing discs and their respective recesses.

Turning now to Fig. 6, the details of the clamp assembly 26 will now be described. In particular, each of the clamp assemblies 36 basically comprises two pivotable members or jaws 54 and 56, a spring lock clip 58, a slide 60, a pivot pin or axle 62, a set screw 64, an adjustment screw 66, a biasing spring 68, another adjustment screw 70, and another biasing spring 72. The details of those components will be described shortly. Suffice for now to state that the jaw 54 is configured to be pivoted by a user about an axis 74 to engage a portion of the planar side edge 10 of the CT patient support panel 2 A when the system 20 is used with that couch-top to precisely position the rail assembly at the desired longitudinal position along that couch-top. The pivotable jaw 56 is also configured to be pivoted by the user about the axis 74 to engage the curved side edge 12 of the IGRT patient support panel 2B when the system 20 is used with that couch-top to precisely position the rail assembly at the desired longitudinal position along that couch-top. In either case, a portion (to be described in detail later) of the pivotable jaw 56 which is not in engagement with the side edge of the couch-top stabilizes or assists the pivotable jaw 54 that is in such engagement with the side edge of the couch-top to ensure that the engaging jaw is securely in place in engagement with the side edge of the patient support panel so that it is resistant to undesirable displacement. Another portion (to be described in detail later) of the pivotable jaw 56 stabilizes or assists the portion of that jaw that is in engagement with the side edge of the patient support panel to ensure the security of such engagement whereupon it is resistant to undesirable displacement.

The jaws 54 and 56 are mounted on the slide 60. As will be described in detail later the slide 60 is configured to carry the jaws from an outboard or retracted position to an inboard or extended position, and vice versa. When the jaws are in the retracted position they are remote from the side edge of the couch-top to which the clamp assembly is to be releasably secured. When the jaws are in the extended position they are closely adjacent to the side edge of the couch-top to which the clamp assembly is to be releasably secured. When in the retracted position the jaws can be pivoted about the axis 74 to prepare them for engagement with the side edge of the particular couch-top to which the particular jaw is to be releasably secured. For example, to releasably clamp the jaw 54 to the side edge 10 of the CT couch-top 2A the user slides the slide 60 to the retracted position, thus carrying the jaws 54 and 56 to that position. The jaw 56 is then pivoted by the user about the axis 74 in the counter-clockwise direction as shown by the double headed arrow 80 in Fig. 6. This action prepares a portion of the jaw 54 (i.e., a front face 54B and a flange 54A, to be described later) for engagement with the planar surface 10 and the contiguous undersurface, respectively, of the CT couch-top 2A. Conversely, pivoting the jaw 56 in the clockwise direction results in the disengagement of those engaging surfaces, thereby freeing the clamp assembly from the couch-top. The releasable clamping of the jaw 56 to the side edge 12 of the IGRT couch-top 2B is achieved in a similar manner. In particular, the user slides the slide 60 to the retracted position, thus carrying the jaws 54 and 56 to that position. The jaw 56 is then pivoted by the user about the axis 74 in the clockwise direction as shown by the double headed arrow 80 in Fig. 6. This action brings a surface portion of the jaw 56 (i.e., a curved recess 56B, to be described later) into engagement with the arcuate surface 12 of the IGRT couch-top. Conversely, pivoting the jaw 56 in the counter-clockwise direction results in the disengagement of that surface of the jaw 56 from the arcuate surface 12 of the couch-top 2B, thereby freeing the clamp assembly from that couch-top.

The jaw 56 is in the form of an elongated tongue-like member terminating at a free end 56A. The upper surface of the jaw is slightly recessed and constitutes the heretofore identified curved recess surface 56B. That surface is shaped to mate with a portion of the curved surface 12 of the IGRT couch-top 2B so that it can be brought into intimate engagement therewith to releasably secure the jaw 56 to the side edge 12 of the IGRT couch-top 2B. The base 56C of the jaw 56 includes a transversely extending central passageway 56D in which the axle 62 is located. The axle is fixedly secured in the passageway by means of the set screw 64 extending through a threaded portion of the base. The opposed ends of the axle projects outward from the sides of the base 56C. The axle serves to pivotably mount the jaw 56 to the slide 60. To that end, the slide 60 includes an axially aligned pair of holes 60A in which the projecting ends of the axle are located to enable the jaw 56 to pivot about the axis 74.

An extension 56E in the form of a generally planar wall projects downward from the base 56C of the jaw 56 and extends approximately perpendicularly to the tongue-like portion of the jaw. The extension 56 serves to slidably mount the jaw 54 thereon so that the jaw 54 can be slid up and down the extension in the direction of the double headed arrow 76 in Fig. 6. This feature enables one to adjust the amount of opening of the jaw 54 to accommodate the particular thickness of the CT couch- top to which the clamping assembly will be releasably secured. That adjustment will be described later. In order to mount the jaw 54 on the extension 56E of the jaw 56, the extension 56E includes a central elongated, linear slot 56F. The slot 56F is configured to receive a bracket 54D (to be described later) of the jaw 54 and extends from a point closely adjacent the base 56C of the jaw to a point close to the bottom edge of the extension 56E. A tab 56J projects outward from one side of the extension 56E immediately below the base 56C of the jaw56. A threaded hole 56G extends through the bottom of the extension 56E and is in communication with the slot 56F.

The jaw 54 is a generally L-shaped body having flange 54A projecting outward from front face 54B of the jaw at the bottom thereon. A slot or channel 54C is provided in the back wall of the jaw 54 opposite the front face 54B. The flange 54A serves to engage the undersurface of the CT-couch-top contiguous with the planar edge 10 of the couch-top, while the front face 54B of the jaw engages that planar edge when the jaw 54 is in the closed or locked position. The heretofore mentioned bracket 54D is located within the channel 54C. The bracket is of a parallelepiped shape, whose width is just slightly less than the width of the slot 56F of the jaw 56. The jaw 54 is slidably mounted on the extension 56E of the jaw 56 by locating the extension 56E within the channel 54C and with the bracket 54D located within the slot 56F. A threaded hole 54E extends through the bracket 54D. The jaw 54 also includes a notch 54G in one of its sides adjacent the top end of the jaw. The notch 54G of the jaw 54 is arranged to receive and engage the tab 56J of the jaw 56. The tab 56J forms as a bearing surface to help prevent rotation of the 54 about a longitudinal axis parallel to 74 due to potential off center loading if forces come to bear on flange 54A.

The heretofore identified adjustment screw 66 serves to establish the position of the jaw 54 on the extension 56E of the jaw 56. The adjustment screw 66 is a threaded member which extends through a hole (not shown) in the base 56C of the jaw 56, into the slot 56F, through the threaded hole 54E of the bracket 54D and into the hole 56G of the extension 56E. Since the hole 54E of the bracket 54D is threaded, rotation of the adjustment screw will raise or lower the jaw 54 with respect to the extension 56E depending upon the direction of rotation of the adjustment screw 66. In order to prevent accidental rotation of the adjustment screw, the biasing spring, 68, which is a compression spring, is located within the slot 56F, between the upper end surface of that slot and the upper surface of the bracket 54D. Thus, the bias action of the spring 68 prevents accidental rotation of the screw to thereby hold it in the position to which it had been rotated to thus fix the position of the jaw 54 with respect to the extension 56E.

In order to provide the user with information regarding the position of the jaw 54 with respect to the extension 56E, indicia in the form of a scale 56H are provided on the back surface of the extension adjacent the bottom of the slot 56F. A pointer 54H is provided on the back surface of the jaw 54 immediately adjacent the channel 54C. Thus, when the jaw 54 is mounted on the extension 56E of the jaw 56, and moved to any position thereon by the rotation of the adjustment screw 66, the pointer 54H will align with one of the indicia of the scale 56H. That action indicates the position of the jaw 54 with respect to the extension 56E to thereby enable the user of the clamp assembly to precisely position the jaw to a desired setting to accommodate the particular thickness of the CT couch-top to which the clamp assembly will be releasably secured. A portion 561 of the rear surface of the extension 56E which is adjacent the slot 56F and on the opposite side thereof from the scale 56H serves as a stop surface. As will be described later, it is that surface which the free end of the adjustment screw 70 engages to establish the amount of pivoting of the jaw 56 about the axis 74.

The slide 60 basically comprises a central base portion 60B in which the heretofore identified aligned holes 60A are located, a generally planar body portion 60C and a handle portion 60D. A pair of side walls 60E project downward from opposite side edges of the body portion 60C. A window 60F is located in the body portion 60C, closely adjacent the holes 60A. The window 60F serves to receive the base portion 56C of the jaw 56 when the jaw is pivotably mounted on the slide via the axle 62 extending through the aligned holes 60A. An stop member 60G having a planar front surface and an angularly extending rear surface projects upward from the body portion 60C of the slide. A recessed threaded hole 60H extends through the handle portion 60D of the slide from the top surface of the handle portion to its bottom surface. The hole 60H is arranged to threadedly receive the adjustment screw 70. That screw may be in the form of a thumbscrew having a knurled head 70A. The biasing spring 72, which is a compression spring, is located within the recessed portion of the hole 60H and is interposed between the head 70A of the screw 70 and the recessed bottom of the hole 60H. The free end of the handle portion 60D of the slide includes a slight depression 601 in it. The depression 601 is provided as a place which can be pressed by the user to push the slide to its closed or extended position, to effect the releasable securement of the clamp assembly to the couch-top, as will be described later. An inclined cam surface 60J extends on either side of the window 60E where the planar body portion 60C of the slide merges with the slide's base 60B. As will be described later the cam surface 60 J cooperates with portions of the undersurface of the spring lock clip 58. Flexure of the spring lock clip when the user presses upward on portions 58D of the spring lock clip 58 enables the slide to be moved to the retracted position.

As best seen in Fig. 18 the free end 70B of the adjustment screw is configured to be extended out of the bottom of the hole 60H on the underside of the handle portion 60D by the clockwise rotation of the screw. That free end 70B when so extended serves to engage a portion 561 of the back surface of the extension 56E of the jaw 56 to establish the degree of pivoting the jaw 56 can achieve. In particular when the adjustment screw is rotated in the clockwise direction it will cause the free end 70B of the screw to extend out of the underside of the handle portion of the slide, to engage a portion 561 of the back surface of the extension 56E. That action will reduce the angle that the jaw 56 can pivot. When the adjustment screw is rotated in the counterclockwise direction so as to retract it to the point at which its free end 70B no longer extends out of the bottom of the handle portion of the slide, the back surface 561 of the extension 56E will be enabled to abut the undersurface of the handle portion of the slide, thereby establishing the maximum angle that the jaw 56 can pivot, and hence the maximum thickness of the IGRT couch-top edge that can be accommodated. To adjust the clamp assembly to accommodate an IGRT couch-top which is of lesser thickness, all that the user has to do is to rotate the adjustment screw in the clockwise direction to cause the free end 70B to project a desired distance beyond the undersurface of the handle portion to engage to surface 561 of the extension for that particular thickness IGRT couch-top.

The downwardly extending side walls 60E of the slide are configured to fit between the side edges of the recess 40 in the cross-bar 30, so that those edges of the recess establish the path along which the slide can be slid. The sliding of the slide outward with respect to the couch-top carries the clamps 54 and 56 away from the couch-top to effect the disconnection of whichever clamp 54 or 56 was in engagement with the side edge of the couch-top. The slide is prevented from sliding outward by the spring lock clip 58, until such sliding action is desired. To that end the spring lock clip is configured to be flexed from a closed position, in which it prevents the slide 60 from sliding outward with respect to the couch-top, to an open position, in which the slide is freed to slide outward. The spring lock clip 58 basically comprises a generally planar member in which an elongated rectangular window 58A is located. The spring lock clip is disposed over the slide 60, with the projection 60G of the slide extending through the window 58 A. The spring lock clip is fixedly secured to the end portion 38 of the cross-bar 30 by the plural screws 42 (Figs. 7 and 10, extending through aligned holes 58B of the spring lock clip and into threaded holes (not shown) in the underside of the bracket 32. Thus, the spring lock clip is fixedly secured to the cross-bar 30 between the cross-bar and the bracket 32. The forward end 58C of the spring lock clip 58 is thicker than the portions of the spring lock clip contiguous with the window 58A and is in the form of two rounded ears or tabs 58D. The portion of the forward end 58C contiguous with the forward end of the window 58A is in the form of an arcuate cam surface 58E (Figs. 17 and 18) and is configured to mate with the surface 60.1 of the slide 60 when the spring lock clip is in its un-flexed state. Thus, those engaging surface prevent the slide 60 from sliding outward with respect to the couch-top. The spring lock clip is formed of any suitable material, e.g., a plastic, so that its forward end portion 58C can be lifted upward by pressing and lifting either or both of the ears or tabs 58D. That causes the portion of the spring lock clip between the forward end 58C and the portion of the spring lock clip sandwiched between the bracket 32 and the cross-bar 30 to bend or flex upward, thereby disengaging the surface 58E from the surface 60J of the slide, whereupon the slide is freed. Such action is accomplished when the user wishes to free the clamp assembly from releasable securement with the couch-top to which it had been secured. For example, the operation of the clamp assembly 36 to free it from releasable securement to the CT couch-top 2A, will now be described with reference to Figs. 7, 9, and 17. Thus, as can be seen in those figures, the slide 60 will be in the extended position with the front face 54B of the jaw 54 in intimate engagement with the planar edge 10 of the couch-top 2A, while the jaw's flange 54A is in intimate engagement with the undersurface of the couch-top contiguous with the planar side edge. Moreover, the distal end 56A of the jaw 56 will be disposed on the inclined surface 40A of the cross-bar 30, and trapped under the overlying portion of the slide 30, as clearly shown in Fig. 17. Thus, the jaw 56 will be prevented from rotating out of that locked position. Further still, the slide will also be locked in that position by the engagement of the surface 58E of tire spring lock clip 58 with the mating surface 60J of the slide 60 as also shown in Fig. 17.

In order to free the slide, so that it can be pulled to the retracted position, the user presses and lifts up on one or both of the tab portions 58D of the spring lock clip 58, to cause it to flex or bend, like shown in Fig. 10. This action frees the surface 60J of the slide from the surface 58E of the spring lock clip, whereupon the user can pull on the slide's handle portion 60D to slide the slide outward in the recess 40 of the cross-bar 30 to the retracted position. This frees the clamp assembly from the couch-top 2A. When the slide is in the fully retracted position the front face of the projection 60G will engage the end of the window 58A, as shown in Fig. 1 1 , to thereby act as a stop preventing the slide from being retracted out of clamp assembly 36.

Each of the other clamp assemblies 36 can be released from securement to the respective portions of the CT couch-top 2A to which they had be connected in a similar manner. When all of the clamp assemblies 36 have been released from engagement with the CT couch-top 2A the rail assembly 22 can be removed from the CT couch-top. The rail assembly can then be mounted on another CT couch-top 2A or on an IGRT couch-top.

Assuming that the rail assembly 22 is now to be mounted onto an IGRT couch-top 2B, that action is accomplished as follows. The rail assembly 22, with each of its clamp assemblies 36 in their retracted positions is disposed on the IGRT couch-top 2B so that the locators 34 of the rail assembly 22 are disposed within the indexing recesses 14 at the desired longitudinal position on the couch-top, like shown in Fig. 12. The user can pivot the jaw 56 of each of the clamp assemblies to the open position, like shown in Fig. 12 (if gravity hadn't already accomplished that action). The user can then press on the depression 601 at the end of the handle portion 60D of the slide 60 to move the slide inward to assume its extended or locked position like shown in Figs. 13 -15 and 18. The inward sliding of the slide causes the undersurface of the portion 58C of the spring lock clip 58 to ride up on the cam surfaces 60J of the slide, thereby causing that portion of the spring lock clip to flex upward. That action enables the slide to clear the spring lock clip to move to its extended position. In particular once the front face surface 60J of the slide 60 has reached the location of the surface 58E of the spring lock clip, the spring lock clip then flexes back to its un-flexed or natural state, whereupon the surface 58E of the spring lock clip will be in engagement with the surface 60J of the slide. The user can then rotate the adjustment screw 70 in the clockwise direction to cause its free end 70B to engage the back surface 561 of the jaw 56. Continued rotation of the adjustment screw will cause the free end to extend further away from the undersurface of the slide's handle and hence concomitantly pivot the jaw 56 in the counter-clockwise direction until the curved recess 56B of the jaw tightly engages the arcuate surface 12 of the couch-top 2B as shown in Figs. 13 - 15 and 18. The jaw will be held in that rotated position by the engagement of the end 70B of the screw 70 on the back surface 561 of the jaw's extension 56E. As should be appreciated by those skilled in the art the engagement of the surface 561 of the pivotable jaw 56 with either the end surface 70B of the screw 70 (or the contiguous undersurface of the handle portion 60D of the slide 60, as the case may be) while the arcuate surface 56B of the jaw stabilizes or assists the engagement of that jaw portion with the arcuate surface 12 of the couch-top 2B.

Once that first clamp assembly has been secured to the couch-top 2B, the other clamp assemblies can be secured to it in the same manner. Moreover, it should be appreciated that by virtue of the construction of the locators 34, i.e., that they provide some "give" or positioning movement within the indexing recesses 14, the locking of any clamp assembly 36 in place to the couch-top 2B, will not interfere with the securement and locking in place of the other clamp assemblies.

When it is desired to remove the rail assembly 22 from the IGRT couch-top, all that is required is for the user to release each of the clamp assemblies in a similar manner as discussed with respect to the release of those assemblies from a CT couch-top.

Turning now to Fig. 19, the patient positioning system 120 will now be described. As can be seen therein the patient positioning system 120 basically comprises a positioning component in the form of an overlay 100 having two clamp assemblies 136. The clamp assemblies 136 serve as the means for releasably mounting the overlay 100 onto either a CT couch-top 2A or an IGRT couch-top 2B. Each of the clamp assemblies 136 is constructed similarly to the clamp assemblies 36 described above, except that each of the clamp assemblies 136 includes a mounting plate with a recess (each to be described later) serving as the means to mount the clamp assembly 136 to the overlay in place of the cross-bar 30 (which serves as the means for mounting the clamp assembly 36 to the rail assembly 22). Thus, in the interest of brevity the common components of the both patient positioning systems 20 and 120, and both couch-tops 2A and 2B, will be given the same reference numbers and the details of their construction and operation will not be reiterated. In particular, it can be seen that the overlay 100 basically comprises a generally planar panel 102 which is particularly suited for mounting a conventional head and neck thermoforming mask (not shown) or a conventional head, neck and shoulder thermoforming mask (not shown). As is known those masks serve to immobilize the head and neck of a patient on a couch-top.

The overlay panel 102 includes a head and neck receiving portion 102 A and a shoulder receiving portion 102B. The portion 102 A includes a recess 104 in its upper surface for receipt of a formed foam head-rest (not shown). A plurality of holes or apertures 106 are provided along portions of the periphery of the head and neck receiving portion 102 A and along portion of the periphery of the shoulder receiving portion 102B. A pair of grooves or recesses 108 is disposed on opposite edges of the shoulder receiving portion 102B. Each groove or recess 108 has a respective clamp assembly 136 mounted therein to enable the overlay 100 to be releasably secured to either couch-top 2A or 2B in the same manner as described above with reference to the securement of the rail assembly 22 to those couch-tops. To that end, each clamp assembly 136 of the overlay 100 is of the same basic construction and operation as described above, except for the inclusion of a mounting plate 130 (Figs. 20 - 22). Each mounting plate 130 serves as the means for mounting the associated clamp assembly 136 within an associated recess 108. In particular, the mounting plate 130 is a generally planar member of generally rectangular profile. The size and shape of the mounting plate is selected to fit closely within the recess 108 of the overlay and is fixedly secured therein by plural screws 1 10. The screws extend into threaded holes 1 12 in the top surface of the recess 108 of the overlay. The central portion of each recess 108 includes a channel 1 14 (Figs. 20 - 22) cut therein to accommodate the projection 60G of the slide 60.

Each mounting plate 130 includes a recess 140 (Fig. 21 ) extending from its outer edge inward. The recess 140 is similar in size, shape and construction to the recess 40 at each end of the cross-bar 30 of the rail assembly 22. Each recess 140 is arranged to accommodate a portion of an associated clamp assembly 136 therein to mount the clamp assembly within the recess. Moreover, each recess 140 includes an inclined ledge surface 40A that serves the same function that the inclined ledge surface provides for the clamp assembly 36, i.e., it is configured to be engaged by a portion of the associated clamp assembly 136 to hold the clamp assembly 136 in its locked position. Thus, the distal end 56A of the jaw 56 of each clamp assembly 136 will be disposed on the inclined surface 40A of the mounting plate 130, and trapped under the overlying portion of the slide 30, as clearly shown in Fig. 22 when the clamp assembly 136 is in its closed or locked position. The jaw 56 of the clamp assembly 136 will thus be prevented from rotating out of that locked position. Further still, the slide 60 will also be locked in that position by the engagement of the surface 58E of the spring lock clip 58 with the mating surface 60 J of the slide 60 as also shown in Fig. 22. As best seen in Fig. 21 the undersurface of the overlay panel 102 contiguous with each of the recesses 108 includes a threaded hole 1 16. That hole is arranged to threadedly receive the screw 52 of an associated indexing locator 34 to mount that indexing locator onto the undersurface of the overlay panel 102.

It should be pointed out at this juncture various changes can be made to the exemplary embodiments of the invention as described above. For example, the inclined surface 40 A of the overlay 100 component, and the inclined surface 40A of the rail assembly 22 component, (which serve to stabilize the engagement of the jaw 54 of the clamp assembly in engagement with the edge of the patient support panel 2A), need not be part of those components. Thus, the inclined surface 40A could be made a portion of the clamp assembly itself.

Without further elaboration the foregoing will so fully illustrate our invention that others may, by applying current or future knowledge, adopt the same for use under various conditions of service.