Attachment 3 Absorbed Dose Reconstruction for Family Member of 1-131 Patient

A terminally ill patient with metastatic thyroid cancer and severe renal insufficiency was treated as an inpatient with 10,545 MBq (285 mCi) Na131I. The patient died six days after radiopharrnaceutical administration while still in the hospital. A close relative of the patient disregarded the instructions of the Radiation Safety Officer (RSO) and insisted upon staying close to the patient for long periods of time until the patient's death. The licensee later reported to the Nuclear Regulatory Commission (NRC) that this member of the public had likely received a dose in excess of the 1 mSv (100 mrem) regulatory limit. The NRC subsequently performed a dose reconstruction and determined that the family member received an exposure of 15 cSv (rem) total effective dose equivalent (TEDE). An analysis of the NRC's approach and an alternative dose reconstruction, in which the TEDE was determined to be approximately a factor of as much as 17 lower, is presented.