Abstract
BACKGROUND: The administration of (177)Lu-DOTATATE peptide receptor radionuclide therapy to patients for the treatment of well-differentiated, metastatic neuroendocrine tumours poses an external radiation hazard due to gamma emissions of lutetium-177. Patients are provided with standardised precautions to follow in the first 16 days following therapy, distancing themselves from family members and to limit their radiation exposure to less than 5mSv in 5 years in compliance with UK legislation. The purpose of this study was to measure the radiation exposure of adult family members of patients undergoing (177)Lu-DOTATATE radionuclide therapy using thermoluminescent dosimeters (TLDs) worn continuously for 4 weeks following therapy administration, and to establish whether existing radiation protection precautions are adequately protecting patients' family members. RESULTS: Participating family members (n = 12) received a median of 0.038 mSv effective dose over 4 weeks from patients administered a median of 7515 MBq (177)Lu-DOTATATE. Patients remained in the Nuclear Medicine department for an average of 6.2 h post-administration and at the time of discharge the median dose rates were 150 µSv/h at 0.1 m and 15 µSv/h at 1 m from the patient's anterior abdomen, corresponding to a median lutetium-177 retention of 35.8% of the administered activity at the time of discharge measured using quantitative SPECT-CT imaging. Family members spent a median total time over the 4 week measurement period of 39.5 h at 1 m and 19.9 h at less than 1 m from the patient. CONCLUSION: Implementing standardised contact restrictions for patients and their family members following (177)Lu-DOTATATE PRRT limits the dose received by family members to less than 5 mSv in 5 years, ensuring sufficient protection and compliance with the UK legislation.