Radiation Dose to the Occupational Worker during the Synthesis of Re-labeled Radiopharmaceuticals in the Nuclear Medicine Department.

Aim: The aim of this study is to estimate whole-body radiation dose to the radiopharmacist involved in labeling of three different Re-labeled compounds, namely, Re-Lipiodol, Re-tin colloid, and Re-hydroxyl-ethylidene-diphosphonate (HEDP) and to compare the occupational burden with the dose limits recommended by Atomic Energy Regulatory Board, India.

Materials And Methods: The Department of Nuclear Medicine at Fortis Memorial Research Institute currently synthesizes three different Rhenium-188 labeled compounds, namely, Re-Lipiodol, Re-HEDP, and Re-tin colloid. To estimate the radiation exposure to the radiopharmacist involved in the synthesis, a survey meter was used to measure radiation level before the start of labeling procedure in the radiopharmacy by keeping it at the location where the radiopharmacist normally stands during preparation. Data were collected for 6 syntheses of each Re-Lipiodol, 4 for Re-HEDP, and 3 for Re-tin colloid followed by the quality control. The pocket dosimeter was used by the radiopharmacistat chest level, performing the labeling of Re-labeled compounds. All radiopharmaceuticals were synthesized by a single radiopharmacist.

Results: 1850 MBq (50 mCi) W-Re generator was eluted before the preparation of each radiopharmaceutical. The amount of ReO4 used for labeling with lipiodol/4-hexadecyl-1,2,9,9-tetramethyl-4,7-diaza-1,10-decanethiol, HEDP, and Tin colloid was in the range of 3182-4440 MBq (86-120 mCi), 2812-3774 MBq (76-102 mCi), and 962-1295 MBq (26-35 mCi), respectively. Meantime required to complete the synthesis was 95, 40, and 131.5 min, respectively. Mean whole-body effective dose received was 0.052, 0.009, and 0.004 mSv, respectively, as measured by using the pocket dosimeter.

Conclusion: From this small study, we observed that the whole-body radiation dose to the radiopharmacist in radiolabeling and quality control of Re-labeled radiopharmaceuticals is within prescribed limits at the current synthesis frequency.