Patent Number: 059862750
Section: description

DETAILED DESCRIPTION OF THE INVENTION The device and method of the invention are described below, by reference to the drawings, in which like numbers represent like elements. While lead is a preferred material for the chamber and shutter, so as to ensure radiation-opacity, other radiation-attenuating materials are known, and may be employed alone, or in conjunction with lead. The spring shown is a simple clip spring design, but coiled springs, leaf springs and the like could also be employed. The reusable, shielded marker source 100 illustrated in the FIG. 1 has a spring loaded source chamber 102. The source chamber is provided with walls 110 illustrated in FIG. 4, and a movable shutter 104, which are comprised of lead or other radiation-shielding material. The shutter may be moved aside by compressing spring 108 for loading the chamber retaining arm 112 with a felt or other absorbant textile, on which is a radionuclide, generally technetium 99m pertechnetate, or other radiopharmaceutical commonly available in diagnostic laboratories. The chamber 102 is loaded by placing a small amount (a droplet or two) of radionuclide solution on felt 114 shown in FIG. 4 contained in the chamber. Once loaded, the lead shutter is closed by releasing the spring. When closed, no radiation is emitted and the diagnostician and the patient are not exposed. When it is time to mark an image, the shutter is opened by squeezing the spring on which the shutter is loaded. This causes alignment of the aperture 106 of the shutter 104 with chamber 102, emitting radiation from the radionuclide on felt 114, which permits rapid localization on the image. This can usually be achieved in a brief period of 1-3 seconds. After completion of marking, the spring 108 is released and the shutter 104 closes moving out of alignment with chamber aperture 106. It is important to note that shutter closing occurs automatically on release of the spring mechanism. Upon release, the source is no longer marking on the image, and no further exposure occurs to medical personnel or the patient. After completion of the marking operation, the device is then put into a secured box or location, until next use. If the next use is sufficiently delayed such that the nuclide has decayed, the chamber is easily emptied simply by opening the shutter, a new felt is prepared, and imaging takes place as described. For ease of operation, compression pads 120 are provided for the operator. The above invention has been described generically, and by specific example, with respect to spring, structures, materials, etc. Alternatives will occur to those of skill in the art, particularly with respect to the type of spring to be employed, radionuclide and other materials to be used, open and rest positions. Such alternatives do not require the exercise of inventive faculty, and remain within the scope of the invention, unless excluded by the recitations of the claims set forth below.