Radiation synovectomy: activity leakage and radiation exposure

Radiation exposure is possible in radiation synovectomy because of an activity leakage. If strict immobilization is observed activity leakage is very low, resulting in a whole body exposure between 30 and 155 mGy. This dosis leads to a tumor risk of 1 per thousand. Using 169Er radiation exposure is negligible because of the very short beta-particle range and the injection of small activities. Up to now, a whole body exposure below 4 mGy was measured. For gonadal exposure a value of 0.2 mGy was found, which is also negligible. Radiation synovectomy in knee prostheses is excepted because of a higher activity leakage. Also excepted is gonadal exposure in radiation synovectomy of the hip because of the additional gamma radiation of rhenium. In these cases, further studies are necessary to optimize the therapeutic procedure. Nevertheless, radiation exposure in radiation synovectomy is of very low risk and an age-related restriction of radiation synovectomy is not necessary. (orig.)