Samarium-153 EDTMP for metastatic bone pain palliation: the impact of europium impurities.

PURPOSE: To evaluate the impact on the radiation protection policies of the radiocontaminants in Samarium-153 ethylenediamine tetramethylene phosphonate ((153)Sm-EDTMP). METHODS: The internal contamination of patients treated with (153)Sm-EDMTP for palliation of painful disseminated multiple bone metastases due to long-lived impurities was assessed by direct measurements. These measurements were coupled with dose-rate measurements close to their bodies and spectroscopic analysis of the residual activity in post-treatment radiopharmaceutical vials. RESULTS: Whole-body counting carried out in six patients showed a 30-81-kBq europium -152 plus europium-154 contamination. The 0.85 mean (152)Eu- to -(154)Eu activity ratio obtained by direct counting was similar to that assessed by analysis of post-treatment residual activities in twelve radiopharmaceutical vials following radiopharmaceutical injection. CONCLUSIONS: The long-lived radiocontaminants in the patient's bodies and the treatment wastes require modifications of the applicable radiation protection policies.

A high-sensitivity multidetector whole-body counter.

A prototype multidetector shadow-shield whole-body counter is presented to be used as a monitor of internal contamination and as a tool in clinical research. The counter is equipped with 16 NaI(Tl) detectors located in the central region of a shielded tunnel surrounding the subject to be measured. The accuracy of the counting efficacy predictions was tested in a group of adults with various body shapes and sizes using X-ray absorptiometry. The precision of the total body potassium measurements allows the use of the counter in clinical follow-up studies.