Once iodine-131 is administered to a patient undergoing therapy, the individual becomes a significant source of radiation exposure to attending staff and other patients. The patient also becomes a source of radioactive contamination since much of the administered radioiodine is gradually eliminated via urinary excretion, exhaled air, and perspiration. Duke University Medical Center uses iodine-131 for three different types of cancer treatments: sodium iodide for thyroid carcinoma, monoclonal antibodies for neoplastic meningitis, and metaiodobenzylguanidine (MiBG) for neuroendocrine tumors. The primary focus of this study was to assess the radiological hazards to the medical staff attending these isolated patients and to members of the general public near the patient rooms. In addition, data from this study were used to design special rooms to house patients undergoing radioiodine therapy. The amount of radioiodine administered to the 17 patients in this study ranged from 2.2 GBq (60 mCi) to 11.2 GBq (303 mCi). Exposure rates were measured using an ion chamber at several locations within patient rooms as well as in the hallway and accessible adjacent rooms. Measurements taken within patient rooms ranged from 4.1 x 10[-8] C kg[-1] hr[-1] (0.16 mR hr[-1]) to 1.7 x 10[-5] C kg[-1] hr[-1] (67 mR hr[-1]). Exposure rates ranged from 8.3 x 10[-9] C kg[-1] hr[-1] (0.032 mR hr[-1]) to 4.1 x 10[-7] C kg[-1] hr[-1] (1.6 mR hr[-1]) in the hallways and accessible adjacent rooms. Thermoluminescent dosimeters (TLDs) mounted on the walls, floor, and ceiling of patient rooms were used to determine accumulated dose equivalents for the duration of the patient treatments. The TLD results ranged from 0.20 mSv (20 mrem) to 19.5 mSv (1,950 mrem). Using a portable GM detector, contamination surveys were performed in patient rooms after the patients were discharged from the hospital. Detected contamination levels ranged from 100 c min[-1] to 240,000 c min[-1]. Air sampling was also performed to determine the concentration of radioiodine in the air and to evaluate the necessity for "negative pressure" patient therapy rooms. Exposure rate measurements and dose equivalent measurements suggest that a potential hazard exists for both the attending medical staff and the general public. Dedicating two new lead lined rooms for iodine-131 therapies would greatly reduce hazards to the general public as well as ease the patient room decontamination process for the radiation safety staff. Air sampling results proved to be inconclusive since activity was seen throughout the air sampling units.Master of Science in Public Healt
