Patent Number: 046706585
Section: description

DESCRIPTION OF THE PERFERRED EMBODIMENTS In FIG. 1 the sheet 10 includes a radio-opaque ply 14 formed of a support matrix and a radio-opaque compound supported by the matrix. A thin, impermeable to liquid polyethylene base ply 12 is attached to and positioned below the radio-opaque ply 14. An absorbant surgical drape ply 16 is attached to and possitioned above radio-opaque ply 14. Plies 12 and 16 reduce any possibility of leakage of the radio-opaque compound into the surgical field. Additionally, ply 16 acts as an absorbant layer to sponge-up blood and other fluids. The radio-opaque ply 14 is a gauze sheet which carries barium sulfate powder. The gauze sheet can be impregnated with the barium sulfate by soaking the gauze sheet in barium sulfate suspension and then evaporating the water thus providing an even distribution of the barium sulfate in the ply 14. Alternatively it might be possible to apply the barium sulfate dry to the gauze. The amount of powdered barium sulfate in the gauze ply can be anywhere from 350 to 730 grams per square foot. This will block anywhere from fifty percent (50%) to one hundred percent (100%) of the incident radiation up to the X-ray frequency generated at a 120 KV setting on the radiology machine. The plies 14 and 16 can be anywhere from one-quarter to one-half inch thick each and the ply 12 can be in the order of two to four mils (0.002 to 0.004 inches). The following test was conducted on the effectiveness of the radio-opaque ply. A fluoroscopic exposure was made of an upper abdomen phantom using a ten inch field, at an X-ray machine setting of ninety KV and three milli-amperes. A pocket radiation dosimeter was placed in the left inguinal region (groin) supported by three-fourths of an inch (0.75 in) thick qauze and held in place by tape. The phantom was then fluoroscoped for five minutes. The radiation dose registered on the pocket dosimeter was eleven millirads. The procedure was repeated replacing the gauze with a three and one-half inch by three inch barium sulfate soaked sheet containing approximately fifty-five (55) grams of barium sulfate thus proving a sheet having a density of about 755 grams per square foot. The sheet measured approximately 0.75 inch in thickness. The phantom was again fluoroscoped for five minutes. The dose registered on the pocket dosimeter was less than one millirad, a reduction of greater than ten to one. Because of the cumulative effect of radiation, any reduction in radiation, even by a small amount, is a benefit to the individual exposed and thus is desirable. Accordingly, this reduction to one-tenth of the exposure that otherwise would occur reduces the risk to all operating personnel. It is contemplated that one useful size of this protective sheet will be in the range of one square foot to two square feet. Sheets of that size can be placed under a doctor's hands during an operative procedure. Such sheets might also be placed adjacent to each other in a pattern with their edges overlapped to define an area in which radiation is not blocked and to provide a blockage of radiation outside of that area. In the case of sheets of this size, the various plys 12, 14, 16 could be held together along their edges by, for example, surgical sterile adhesive tape or by thermal bonding or even by stitching. Where larger sheets may be employed, it might be desirable to include strips of double faced adhesive between the plys to facilitate the handling of the sheet. In the FIG. 2 embodiment, the sheet 20 is a three ply sheet having a center ply 24 that is substantially the same as is the radio-opaque ply 14 of the sheet 10 shown in FIG. 1. However, in this FIG. 2 embodiment, the radio-opaque ply 24 is sandwiched between two liquid impermeable polyethylene plies 22, each of which plies are substantially similiar to the ply 12 in the FIG. 1 embodiment. This FIG. 2 embodiment might be used in circumstances where the liquid absorption characteristic is not required. For example, the FIG. 2 embodiment might be used as a partition around a patient to provide protection for personnel required in the operating room from scatter radiation. However the sheet 20 can be adapted to be used in place of an actual surgical drape by slipping the sheet 20 into an envelope formed of two sheets 32 of normal surgical drape material as shown in FIG. 3. The result is a sheet 30 that is composed of five plies and which provides the liquid absorbant feature. FIG. 4 shows a forth embodiment of a sheet 40 in which powered barium sulfate 42 is carried in plastic pockets 44 of bubble packet type material. A sheet of this barium sulfate filled bubble pack material 45 is attached to a ply of surgical drape material 46 similar to the ply 16 in the FIG. 1 embodiment. In the FIG. 4 embodiment as shown, the bubble pack sheet 45 is one in which a flat ply 45a forms the upper surface of the pockets 44 and a formed sheet 45b is attached to the flat sheet 45a to define individual pockets 44. Certain applications of the sheets 10, 20, 30, 40 of this invention may require much larger sheet material than the one to two square foot material mentioned above. Large protective sheets can be laid over a patient or under a patient or both during an operating procedure. In such a case, the large sheet will require an opening therethrough so that the primary beam of x-ray will not be blocked. Although the above description emphasizes the value of using these sheets to block secondary radiation from impinging on operating personnel, it should be recognized these sheets can be used to protect genitalia, or other body parts, of patients during radiographic procedures. It should be recognized that the use of large size sheets of this invention over and/or below a patient during a fluoroscopic surgical procedure serves to prevent the scatter radiation from passing through the sheets and thus tends to protect all personnel in the operating room. In many fluorscopic procedures, such as angiographic procedures, a catheter is manipulated and introduced through the femoral artery. The tip of the catheter is monitered under fluoroscopic control. If a protective sheet made in accordance with the present invention is used in the inguinal area, under or over the operator's hands, which is the region where the catheter is introduced, a decreased radiation dosage to the operator's hands by a factor of ten would result. Because of the relatively low cost of the protective sheets of this invention, they are disposable and thus need not be used except for a single operation. Thus, sterility in the operating zone is enhanced and cross contamination is avoided. One advantage of maintaining sterility in the operating zone is that a doctor's movements are less inhibited in that his or her contact with the sterilized protective sheet of this invention does not destroy the sterilization procedures.