Patent Number: 041587790
Section: summary

The present invention broadly relates to shields used for the protection of human embryo cells against the effect of that radiation which is produced during exposure to X-rays. Heretofore, in order to attempt to solve the problems relating to X-ray exposures, it has been customary to use a structure which comprises a combination of two semi-circular leather pouches, joined together in the manner of a fan and containing lead shot. This structure has been used particularly for the local screening of the gonad region of the body which, because of danger to embryo cells, must be shielded from this radiation. Thus, the area of the body which must be protected from exposure to X-rays is covered by lead sheets to prevent the biological action of X-rays which, as is well known, is based upon absorption of the rays by the tissues. Disadvantages of this traditional method of screening reside in the complicated and difficult manipulation of the flexible lead sheets to be applied to the body of the person to be X-rayed and in the fact that this method does not provide infallible protection against radiation because of the fact that displacement or slipping of the lead sheets from the place of application may occur. In view of the harmful effects which may result from exposure of which the radiologist is unaware, a method of protection from radiation fulfilling safety requirements and applicable to adults and children of both sexes has been the subject of a long need by the medical profession. Other attempts to solve the problems have been proposed. For example, a sheet of material, transparent to both light and X-rays and having a variety of screening segments of different shape and size, is mounted on the X-ray tube in such a manner that an appropriate one of the segments may be positioned in the path of the light or X-ray beams for shadowing the area to be protected. Another proposal utilizes a generally triangular lead shield having a handle bar extending from its base. The shield is slideable and rotatable through adjustment means on the free end of a telescopic element, which in turn is rotatably mounted on the housing of an x-ray tube. With this arrangement the shield may be adjusted vertically or horizontally in the path of the X-ray beam and the shaded area can be varied by turning the shield about the axis of the handle bar. The object of the present invention is to provide a device which insures reliable and optimal screening of that part of the body which is to be protected from the effects of radiation during the carrying out of X-ray exposures, while nonetheless being manipulatable with ease and facility. The present invention provides a shielding device for the protection of human embryo cells from the effects of radiation during examination by an X-ray machine, which comprises in essence, a protective screen for absorbing radiation which is rotatably secured to a supporting frame. The screen comprises a central protective plate of predetermined shape and a first plurality of additional lead sheets which are linearly displaceable by means of adjusting means such as gears to vary the covering surface area of the screen. Thus, additional lead sheets are controllable dependent on the displacement. An inestimable advantage of the structural arrangement of this protecting device resides in its smooth manipulability in every respect. In addition, there can be no unintentional or unnoticed change of the basic position of the protective screen relative to the part of the body which is to be protected from the X-rays. In fact, there is little if any possibility of inadvertent or unnoticed change of the screen position since the support for the covering surface comprises a frame which when placed on the X-ray table, imparts such stability to the screen that it cannot be influenced by the movements of the person being subjected to the X-rays. In addition, by simple operating processes optimal conditions concerning the adaptation of the covering surface to the surface expansion of the part of the body to be shielded from the effect of the X-rays may be achieved with the device of the present invention. A preferred embodiment of the invention provides structure for increasing or reducing the area to be covered by the protective screen by means of pairs of sheets of lead which are utilized to extend in planes at right angles to each other. Other layers of lead associated therewith are rotatably mounted in pairs on one pair of sheets and are freely and slidably supported at their free ends by means of spring pressure on control cams formed on the other pair of sheets. In order to cause the lead sheets to effect an expansion or reduction movement continuously and uniformly in any direction during adjustment, the linearly displaceable pairings of lead layers are secured in synchronous and oppositely displaceable fashion individually to holders associated with the adjusting gears. The holders are preferably designed as slides for this purpose and are provided with a rack-type extension. The teeth of the rack mesh with a pinion to accomplish the displacement of all linearly displaceable lead sheets and the rack is actuated by the rotation of a knob. Favorable conditions for the variability of the protective screen over a wide range is achievable in a simple manner by means of a structure in which pairings of linearly displaceable associated lead sheets are arranged in different planes of movement. This arrangement permits the layers to slide together in such fashion as to permit overlapping of the parts and the resultant reduction of the surface area of the protective screen so that the application of said screen is practical for the X-raying of children and infants as well as for adults. In order to provide conditions for the universal application of the protective device in connection with X-ray exposures of persons of both sexes, the structure of the present invention also provides that the displaceable sheets of lead form in combination with the center lead plate, a protective screen of elliptical shape and this shape is retained over the entire range of adjustment. Further, the protective screen, which is formed of a lead plate and a plurality of lead sheets, may be displaceable as a unit between two alternative positions which differ from each other by an angle of 90.degree.. This is done by means of a manually operated adjusting device. This accomplishes the beneficial result that the protective device can be brought by a simple adjustment into the particular position in which the device offers optimal conditions for the protection of embryo cells of persons of either sex. When making X-ray films, in order to adapt the protecting device in a simple manner to the various requirements for observing the most favorable distance of the X-ray tube from the area of the body to be protected, the protecting screen is secured to a supporting arm mounted so as to be vertically adjustable on a column. To insure the adjustability of the protecting device in a horizontal plane, the supporting arm may be constructed in telescopic form. According to a further concept of the present invention, the protecting screen may be mounted in another manner, i.e. on a pivot arm formed as a parallelogram guide if the simple adjustability of the protecting screen is insured relative to the area of the body to be screened. Further, in accordance with the present invention, the protecting screen may be protected by a completely enclosing housing or casing. The casing may comprise an upper and a lower part, at least one of these parts being provided with a conical surface inclined in the direction of radiation. In this manner, sufficient security of the adjusting and screening mechanism from harmful external influences is accomplished. Also by avoiding different thicknesses of material in the formation of the casing, no shadows are visible on the X-ray image which could have originated from a locally limited thickness in the material of the casing to be penetrated by the X-rays. For achieving a configuration of the casing suitable for production and also allowing for the functional requirements in an advantageous manner, the casing is formed of two identical parts having the shape of a plate and these two parts are correspondingly provided on their edges with an annular contact surface which connects them together. A special advantage of this construction resides in the fact that only one die or the like has to be prepared for moulding of both parts. While it is not absolutely necessary for the actual purpose and operation of the above described structure, manipulation thereof is considerably facilitated and its operation made clearer if both parts of a casing are of transparent material, such as plexiglass or the like. The advantage of such a construction resides in the fact that it enables the operator to see at a glance the surface expansion and relative position of the lead sheets without requiring attention to scales, marks or the like which otherwise serve to indicate the adjusting processes.