[P108] Radiation safety after 177Lu-dota-tate therapy for neuroendocrine tumors

Purpose To evaluate the safety of peptide receptors radionuclide therapy (PRRT) of neuroendocrine tumors after 7.4 GBq 177Lu-DOTA-TATE by measurement of the radiation exposure rates. Methods For each patient the radiation levels (H∗(10)) were measured at 1 meter distance from the patient abdomen. Measurements were performed with a survey meter at different time points, over 4 days from the treatment administration of a prescribed activity of 7.4 GBq of 177Lu-DOTA-TATE. The first measure was accomplished at the end of the 177Lu-octreotate infusion and before voiding of bladder, while the others were done after emptied the bladder. Results 13 patients (36 cycles) were treated with a mean (standard deviation) activity of 6834 (688) MBq per cycle. Mean (maximum) dose rates measured at 1, 8, 24, 48 and 97 h (mean time) after treatment initiation were 32 (42), 15 (27), 9 (19) 7 (18) and 5 (11) μ Sv/h, respectively. At 8, 24, 48 and 97 h, 90% of the patients radiation levels were below 20, 16, 12 and 8.4 μ Sv/h, respectively. In relation to the first measurement, the mean uptakes were 47, 31, 24 and 16%. Considering the physical decay of the isotope, the dose limits for individual members of the public and an 8 h a day permanence at 1 m of the patient, the maximum dose rate allowed for patient release would be 13 μ Sv/h. Conclusions Taking into account the dose rates at 1 meter and the analysis of the specific conditions of the family and social environment of each patient, after 24 h of the treatment administration the patient can be released in 75% of cases.