A PRELIMINARY STUDY OF THE EXTERNAL DOSE RATES DISTRIBUTION FOR PATIENTS WITH PROSTATE PERMANENT 125I IMPLANTS

The radiation dose rate distribution in the case of 137 patients after I-125 prostate permanent implants, performed at the Institute of Oncology, Bucharest, was experimentally determined. The study was performed on patients diagnosticated with prostate adenocarcinoma in stages T1-T2. After the implant of radioactive sources the radiation level exposure were measured at 2 meters distance from the anterior body surface. The value of the activities of the implanted sources ranged from 580 to 1816 MBq while the exposure dose rates varied between 0.21 and 1.42 mu Sv/h. The radiation exposure levels suggest that patients are not presenting a radiation risk to the general public and to the medical staff following I-125 prostate permanent implants. The dose rates depend mainly on the implanted source activity, but also on the individual anatomical and physiological factors and for this reason no direct correlation was found between the dose rates and the activities of the implanted sources.