Radiation exposure to general public after permanent brachytherapy for prostate cancer

Permanent prostate brachytherapy patients are generally told to limit their time around children and pregnant women. However, there is little data available to validate the instruction. For the skin effective dose rate, ion chamber survey meter model 451B-DE-SI was used. The meter was scanned at the point of 4.5, 20, 50 and 100 cm from the skin surface in each plane. Life time exposure was calculated from the average anterior data. At the point of 4.5 cm from the anterior skin surface, the lifetime equivalent dose was 46.5 mSv, at 20 cm it was 13.2 mSv, at 50 cm it was 3.5 mSv and at 100 cm it was 0.9 mSv. The risk from the prostate brachytherapy patients to general public is quite low. Only the case of close and long-time contact with the pregnant and the infant should be paid attention to.