Multiple implant dosimetry.

Abstract

Low-atomic-number, silver-activated radiophotoluminescent glass-needle dosimeters were placed within a four-portal, 10-mil wall gold shield and implanted in a 38-pound dog. Over 150 needles were implanted, by a trocar technic (Fig. 1). Implants were made in three planes, so that most of the vital organs were pierced (Fig. 2). The shielded needles were placed in a PE-320 polyethylene tube. Spacing of 0.25 inch between needles was maintained by inserting plastic cylindrical spacers. An average of 50 needles located in at least three traverses, in the same plane, were exposed at a T.S.D. of 110 cm. to 260-kvp x-rays delivered at 30 ma, with 1 mm. Al and 0.5 mm. Cu filtration. A circular portal 7 cm. in diameter was used. At mid-exposure, the dog was turned over and the total exposure completed. The gold shield designed to achieve energy-independence (1, 2) is shown in the insert in Figure 1. The theory of this dosimeter and its response have been reported by the authors (3–7). Prior to exposure for dosimetri...