Patent Number: 063255383
Section: description

DETAILED DESCRIPTION OF THE INVENTION FIGS. 1, 3 and 23 show generally the preferred embodiment of the apparatus of the present invention designated generally by the numeral 10. In FIG. 1, the shield is removed for clarity. The apparatus 10 of the present invention provides a shielded x-ray apparatus that includes a frame 11 having a lower end 12 that rests upon a supporting surface such as a floor and an upper end portion 13 that supports a table 14. The table 14 has head and foot end portions 15, 16 respectively and an upper surface 17. The upper surface 17 is receptive of patient 18 as shown. A suitable attachment such as a conventional sliding rail attachment secured by bolting, riveting, welding or the like can be used to form an attachment at 19 between frame 11 and table 14. An x-ray unit 20 includes a base 21 having a vertical section 22, horizontal section 23 and superstructure 26. The superstructure 26 is attached to vertical section 22 with support beam 25. Arrow 34 indicates that beam 25 can be rotatably supported by horizontal section 23 using a motor drive, for example. Support beam 25 pivotally supports superstructure 26 at connections 24 (pinned, for example). Superstructure 26 is comprised of inclined arms 30, 31 and beams 37, 38 that can be generally horizontally positioned. Pinned connections 27, 28 can be used to join the arms 30, 31 to the beams 37, 38 of superstructure 26. Each of the beams 37, 38 supports a yoke. Beam 37 supports yoke 32. Beam 38 supports yoke 33. The beams 37, 38 are supported by inclined arms 30, 31. Pinned connections 27, 28 can be used to join each of the beams 37, 38 to the respective end portions of inclined arms 30, 31 as shown in FIGS. 1 and 3. A pair of monitors 39, 40 can be positioned next to table 11 so that a radiologist can view the monitors 39, 40. Monitors 39, 40 are supported by a frame such as monitor support 41 shown in FIGS. 1 and 3. In FIG. 1, reference line 42 indicates the path that x-rays travel when emitted by radiation generator 36 in the direction of camera 35 which contains film. A pinned connection 45 can be used to join camera 35 to upper yoke 32. Similarly, pinned connection 46 can be used to join x-ray generator 36 to lower yoke 33. Arrows 43, 44 in FIGS. 1 and 3 indicate schematically the pivotal movement of camera 35 and x-ray generator 36 respectively relative to superstructure 26. Arrow 29 in FIGS. 1 and 3 schematically indicates the adjustable movement in a fore and aft direction relative to support 25 of arms 30 and 31. In this fashion, the superstructure 26 can be used to move the position of both camera 35 and x-ray generator 36. A telescoping mechanism (not depicted), located either at arms 30, 31 or at camera 35, can be used to vary the distance between camera 35 and the patient 18. The present invention has particular utility to cardiac catheterization procedures. During cardiac catheterization and intervention, procedures for which the illustrated equipment is typically used, a physician advances catheters into the patient's heart, usually through veins and arteries cannulated in the patients groin or elbow crease. These catheters are then used to inject contrast dye into the patient's cardiac chambers or blood vessels surrounding the heart, and small steerable and/or implantable tools, such as balloons, stents, and rotablators, are used to remove or modify pathologic narrowings of coronary arteries or heart valves. While most of the radiation beam 60 (see FIG. 2) emitted by the generator 36 crosses the table 14 and the patient 18, and ultimately enters the camera 35, a sizable portion is deflected by the different media it encounters on the way, as shown schematically in FIG. 2, leading to scatter radiation, depicted by dotted lines 61. This scatter radiation 61 poses health hazards, most notably the risk of cancer, leukemia, and cataract formation in the eye. Patients, while directly exposed to the X-ray beam 60, are currently felt to be only at moderate risk because the time of exposure is limited. On the other hand, physicians and allied health personnel assisting in the catheterization laboratory are repeatedly exposed to cumulative scatter radiation in doses inverse to the distance from the source. This scatter radiation is confined by the shield 50. Shield 50 consists of a rectangular middle portion 47, located between upper shield section 52 (attached to the camera 35) and lower shield section 53 (attached to the radiation generator). Attention is first directed to the upper and lower shield sections. Each of these shield sections (52, 53) has the shape of a truncated pyramid with four lateral walls 56. Each lateral wall consists of two half pieces 58, 59, which in turn are formed by a plurality of horizontal shield segments 57, joined by hinges 62. FIGS. 5a-5d illustrate this slidable joining of half pieces 58 and 59. FIG. 5c shows a single half piece. The flexible connection of horizontal shield segments 57 through hinges 62 allows for the extension or reduction of the height of the half piece. The two opposing half pieces 58, 59 are connected slidably through projections 64 on half piece 58 which engage matching slots 63 on half piece 59. In so engaging each other, the two opposing halfpieces show a section of overlap 151. This width of this section of overlap 151 will vary, depending on the degree of engagement between the two opposing half pieces 58 and 59. In FIG. 5a, the two half pieces are deeply engaged, forming a large section of overlap 151. In FIG. 5b, the two half pieces are barely joined, forming a small section of overlap 151. This overlapping of the opposing half pieces 58 and 59 is schematically illustrated in FIG. 5d. FIGS. 6a-6b illustrate in detail the projections 64 on half pieces 58, matching the slots 63 on half pieces 59. Also seen in detail is the flexible nature of hinges 62 joining horizontal shield segments 57. It stands to reason that this construction of each of the lateral walls 56 of shield sections 52, 53 allows these shield sections to assume an infinite variety of positions. They can adapt to variations in the distance from camera 35 or radiation generator 36 to middle portion 47 by varying the degree of folding between horizontal shield segments 57 at hinges 62. They can adapt to variations in the size of the middle portion 47 by varying the degree of overlap 151 through increased or decreased engagement of half pieces 58 and 59. They can adapt to rotational movements and to angulated movements of the x-ray ensemble in relation to table 14 and middle portion 47, since the degree of folding between horizontal shield segments 57 can be different for each of the four lateral walls 56. This high degree of possible adaptation is illustrated in FIGS. 4a-4d. In FIG. 7, frame 65 is shown that supports each bellows-like tapered shield sections 52 and 53. Each section 52, 53 is supported from the inside by frame 65 that includes stabilizing rods 66, consisting of three parts connected by a telescoping mechanism (66a, 66b, 66c), as illustrated in FIGS. 7 and 8. Ball joints 67 at the smaller end of these rods 66 fit into sockets 68 located at the radiation generator 36 and the camera 35 respectively. Ball joints 67 at the larger diameter ends of the rods 66 fit into sockets 68 located in connectors 69 and 70. The connectors 69, 70 of a tapered section 52, 53 are connected to each other via shafts 79 and rods 80, whereby the rods 80 lead into tubular openings of the shafts 79 (not depicted), thus forming a telescoping connection (see FIG. 7). The telescoping mechanism of these supporting rods could be moved passively through the relative movement of table, radiation generator, and camera, or better through an internal hydraulic mechanism within the telescoping rods and shafts (not depicted), allowing for active extension or retraction of the three telescoping parts of the rods 66, synchronized with the movements of the ensemble of the X-ray apparatus, using computer guidance. FIGS. 9A and 9B show the connection of tapered sections 52 and 53 to the frame 65 at rods 66. Connector rings 110 are located at each of the two telescoping joints linking the three parts 66a-66c of rods 66. FIG. 9A shows the structure of a connector ring 110. A large ring 110a is attached to the end of rod parts 66a and 66b at the point where the telescoping rod parts meet. Two radially extended struts 110b are attached with one end to the large ring 110a at an orthogonal angle to each other, and each strut has a smaller ring 110c at its other end. The rings 110c are in turn connected to metal loops 71 which are attached to the half pieces 58, 59 of a tapered section 52 or 53 by any conventional means. It should be noted that the size of the connectors shown in FIGS. 9A and 9B, and the distance from the rods to the shields, have been exaggerated for clarity. At the end opposed to the radiation generator 36, the stabilizing rods 66 supporting the lower tapered section 53 are connected via ball joints 67 to connectors 69. These connectors form the corners of a drive unit located within the table board 14, which is depicted in detail in FIGS. 10 and 11. In FIGS. 10-11, table board 14 consists of a base part 14b, and a cover part 14a. Attached to the connectors 69 are shafts 72 containing internal female threads into which thread rods 73 are connected. These threaded rods 73 are driven by small, reversible motors 74 and 75, which rotate the thread rods. Motor 74 is firmly attached to either the table base 14b, or the table cover 14a, whereas motor 75 is not attached to either. The two ends of threaded rods 73 emanating from the motors 74 and 75 have opposing helix directions, such that rotation of the threaded rods 73 in one direction will pull the attached shafts 72 and cubic connectors 69 towards the center of the table, whereas rotation in the opposite direction will push the attached shafts 72 and cubic connectors 69 away from the center of the table. Motor 75 is also attached to an axial shaft 77, which contains an internal female threaded portion into which an axial threaded rod 78 connects. This threaded rod 78 is connected at one end to axial shaft 77, and at its other end to a third motor 76, which is attached firmly to the same portion of the table as motor 74. Rotation, by motor 76, of threaded rod 78 in one direction will pull the assembly of motor 75, threaded rods 73, shafts 72, and connectors 69 towards one end of the table, whereas rotation into the opposite direction will move these parts towards the opposite end of the table. The shafts 72 glide on conventional ball-bearings located in the two side openings 14c and 14d of the table base 14b. In addition, motors 74-76 can be connected to a source of electrical power via conventional electrical power cords 101. FIGS. 12A and 12B show in detail the rod connections of a frame 65 that supports a tapered section 52, 53 and attachment to the drive unit. FIG. 12A shows a view of motor 74, connected via threaded rods 73 and shafts 72 to the connectors 69. Shafts 79 and rods 80 connect the four connectors 69 (only two of which are shown in FIG. 12A), thus forming a rectangle, as also depicted in FIG. 7. FIG. 12B shows a single connector 69, viewed from a different angle, with attached shafts 72 and 79 and rods 80. FIG. 13A depicts the framework of the middle portion or rectangular housing 47 of shield 50. Angle struts 81 are connected via locking bolts 82 to holes 83 in the connectors 69 and 70. A conventional electric power lock mechanism allows for manual closure and central closure or release of the locking bolts 82. FIGS. 14A-14C show different views of the upper and lower ends of angle struts 81, showing locking bolts 82 both in the locked and the released position. Side struts 84 (FIG. 13A) are attached to the angle struts 81 and lead into hollow bars 85, a portion of which is shown enlarged in FIG. 13B, each of which contain two parallel tracks 86 or apertures into which the side struts 84 connect. This allows the ends of the side struts 84 of the opposing angle struts 81 to move in adjacent, parallel tracks 86. The hollow bars 85 are attached to the upper and lower rims of plates 87 which contain a large rectangular opening 92. A row of conventional female snap-fasteners 88a are located around opening 92. Hollow bars 89 are attached to the angle struts 81 in a direction orthogonal to the side struts 84. U-shaped bars 90 fit into the hollow bars 89. The connection of U-shaped bars 90 and hollow bars 89 is such that the ends of U-shaped bars 90 move freely within the hollow bars 89. A compression spring (not depicted) is located within each of the hollow bars 89, and this spring pushes U-shaped bars 90 away from angle struts 81. The length of these springs is such that U-shaped bars 90 and hollow bars 89 will not completely separate. Note that the vertical portion of each U-shaped bar 90 contains a row of conventional female snap-fasteners 88a similar to the snap fasteners 88a on elements 87. Folding, X-ray impermeable screens 91, containing small, slit-like openings 111 located on the upper and lower ends of their folding segments 88 are attached to the middle, rectangular housing portion 47. Side struts 84, the hollow bars 89, and the horizontal portions of U-shaped bars 90 thread through the openings 111, as shown in FIGS. 15A-15C, thus allowing horizontal movements of the screens. The vertical ends of the screens are attached firmly to the vertical portion of the U-shaped bars 90, the vertical rims of angle struts 81, and the vertical rims of plates 87, by any conventional means. This ensemble is depicted in FIGS. 16A and 16B, and forms the side wing of middle portion 47. FIGS. 17A-17C depict "cuffscreens", which are rectangular pieces of flexible, stretchable, radio opaque material with an opening in the middle. These cuff screens can be opened and closed by means of VELCRO hook and loop type fasteners 95a, 96a, 97a, which lead from the openings 95b, 96b, 97b to the upper rim of the cuff screen. The cuff screens fit snugly around those parts of the patient's body that are leaving the middle housing portion 47 (see FIG. 3). Needed are one collar screen 95 for the patient's neck, one belt screen 96 for the waist, and two sleeve screens 97 for the arms. The outer rim of the cuff screens has a rim of male snap-fasteners 88b, which engage the female snap fasteners 88a on elements 81, 87, 90, to allow attachment to the framework of middle housing portion 47. FIG. 18 shows the middle housing portion 47, seen from the head 15 end of the table board 14. FIGS. 19a, 19b and 20 show an armboard 98, which is hooked onto each of the two side wings of middle housing portion 47. These armboards 98 consist of a support rest 99, two rods 100 which slide into receiving tubes 109 within support rest 99 (thus allowing for adjustment of the armboards 98 to the varying distances between angle struts 81), and two side triangles 102, which attach via hooks 104 to sleeves 103 on angle struts 81 (see FIG. 13A). FIG. 20 shows a horizontal cut of the key elements of the framework of middle portion 47 attached to the patient. FIGS. 21A and 21B depict the connection between the upper tapered section 52 and the upper portion of middle housing portion 47. The lowermost segments of section 52 are attached to connectors 70. The upper ends of angle struts 81 are attached to connectors 70 by passing bolts 82 through holes 120 located in shield section 52, and then into holes 83 of connectors 70. One half of the lowermost segments of shield section 52 has a row of female snap fasteners 88a. Flexible collar screens 95 attach with male snap fasteners 88b to the female snap fasteners 88a located on the vertical portions of U-shaped bars 90 and the lowermost segments of shield section 52. Seen from the foot end of the table, the view would be similar, except that belt screen 96 would replace collar screen 95. FIG. 22 depicts the connection between the upper portion of tapered section 53 and the lower portion of middle housing portion 47. The uppermost segments of tapered section 53 are attached firmly to the lower half of connectors 69. The lower ends of angle struts 81 are connected to the upper half of connectors 69 by inserting locking bolts 82 into holes 83. FIG. 23 is a side view of the invention, showing the connection of the lower portion of shield 50 to radiation generator 36 via a special connection piece 93. Connection piece 93 is rectangular at its base, where it is firmly attached to the lowermost folding segment of tapered section 53. It is circular at its lower end, where it is firmly attached to the upper rim of radiation generator 36 at attachment, completely enclosing the connection of rods 66, ball joints 67, and joint sockets 68. A similar connection piece 94 is firmly attached with its rectangular base attachment 54 to the uppermost folding segment of tapered section 52, and with its circular end connected to the lower rim of camera 35, again covering the connection of parts 66, 67, 68. Both connection pieces 93 and 94 are made of radio impermeable material. While many different variations of this design are possible to achieve the radiation shielding goals (the depicted design is only one of many different options), the unique new feature of this invention is the near complete isolation of the radiation space between the generator 36 and the camera 35 through a mobile shield that always adapts to the varying geometric relationships between the X-ray apparatus and the different organs in the patient's chest targeted for examination. The radiation beam 60 in its various positions in relation to the patient is always enclosed, allowing no scatter radiation 61 to escape. An important point is that the material and structure of shield sections 52, 53 allow for asymmetry of the shields, which will occur as the X-ray apparatus moves, that it allow for a variation in the distance between radiation generator 36 and camera 35, and for a variation in the distance between either of these parts and table board 14. The waist collar 96 has to be quite flexible, and the entire lower portion of this part has to be covered in sterile sheets, in order to allow the operator to move the region of vascular access into the radiation field for x-ray guidance, should this become necessary due to access problems. The support structure of shield 50 has to be sufficient to allow the free passage of the radiation beam on its way from the radiation generator to the camera, without swinging of the shields into the trajectory of the X-ray beam when the shields assume angulated positions. This is achieved through the stabilizing rods 66 in this design, but other mechanisms can be used to achieve the same effect. The middle portion has been depicted as a simple assembly of a frame structure with folding screens and cuff screens with sleeve openings, but multiple variations of this design are also possible. The present invention will allow open access to the patient's head, arms and groins. The only remaining leaks for scatter radiation are those parts of the patient's body which are emanating from the isolated radiation space. A telescoping mechanism located at camera 35 could be used to allow the camera to protrude to varying degrees directly into the shielded space formed by tapered section 52. Several other features are important. The device of the present invention can be disassembled very quickly, so that effective cardiopulmonary resuscitation can be rendered without delay in the case of cardiac arrest. Sensitive radiation detection devices have to be installed outside the confinements of the radiation field isolator, in order to prevent accidental exposure of the operators to scatter radiation leaks. While the device presented is intended for diagnostic and therapeutic procedures using radiation for imaging purposes, minor modifications in the design would easily allow to use this device for radiation therapy. Although the Radiation Field Isolator and the method of using the same according to the present invention have been described in the foregoing specification with considerable details, it is to be understood that modifications may be made to the invention which do not exceed the scope of the appended claims, and modified forms of the present invention done by others skilled in the art to which the invention pertains will be considered infringements of this invention when those modified forms fall within the claimed scope of this invention. The following is a list of parts and materials suitable for use in the present invention: PARTS LIST Part Number Description 10 shielded x-ray apparatus 11 frame 12 lower end portion 13 upper end portion 14 table 14a cover part 14b base part 14c opening 14d opening 15 head end 16 foot end 17 upper surface 18 patient 19 attachment 20 x-ray unit 21 base 22 vertical section 23 horizontal section 24 pinned connection 25 support beam 26 superstructure 27 pinned connection 28 pinned connection 29 arrow 30 arm 31 arm 32 upper yoke 33 lower yoke 34 arrow 35 camera 36 radiation generator 37 beam 38 beam 39 monitor 40 monitor 41 monitor support 42 reference line 43 arrow 44 arrow 45 pinned connection 46 pinned connection 47 rectangular housing or middle portion 48 wall 49 flexible panel 50 shield 51 opening 52 upper tapered section 53 lower tapered section 54 upper attachment 55 lower attachment 56 flexible lateral wall 57 horizontal shield segments 58 half piece 59 half piece 60 radiation beam 61 scatter radiation 62 hinge 63 slotted receptacle 64 projecting member 65 frame 66 rod 66a telescoping part 66b telescoping part 66c telescoping part 67 ball joint 68 socket 69 connector 70 connector 71 loop 72 shaft 73 threaded rod 74 reversible motor 75 reversible motor 76 reversible motor 77 axial shaft 78 threaded rod 79 shaft 80 rod 81 angle strut 82 locking bolt 83 hole 84 side strut 85 bar 86 parallel tracks 87 plate 88 folding segment 88a female snap fastener 88b male snap fastener 89 bar 90 bar 91 screen 92 opening 93 connecting piece 94 connecting piece 95 collar screen 95a VELCRO fastener of collar screen 96 belt screen 96a VELCRO fastener of belt screen 96b opening of belt screen 97 sleeve screen 97a VELCRO fastener of sleeve screen 97b opening of sleeve screen 98 armboard 99 support rest 100 rod 101 power cord 102 side triangle 103 sleeves 104 hooks 109 receiving tubes 110 connector ring 110a ring 110b strut 110c small ring 111 slit like opening 120 hole 151 section of overlap The forgoing embodiments are presented by way of example only; the scope of the present invention to be limited only by the following claims.