Evaluation of Reduction in Radiation Dose Rates from Patients Receiving Iodine-131 Therapy for Thyrotoxicosis and Thyroid Cancer

Abstract

The measurement of radiation dose rates is important in the release of patients treated with radioactive iodine. Radioactive patients present radiation hazards to others after radiopharmaceutical administrations and evaluation of the radiation dose rate close to patients is important. The annual public dose limit is 1 mSv, though the family members are allowed to receive higher doses but as per IAEA guidelines should not exceed 5mSv over 5 years. In the present research radiation dose rates were measured from radioactive patients without the influence of scattered radiation and correction factors. Total 200 patients suffering thyrotoxicosis and (Carcinoma) thyroid disease treated with radioactive iodine I-131 at PIUNM cancer hospital were evaluated. The measurements were performed at a distance of 0.5m, 1.0 m, 1.5m and 2.0m in front of the thyroid tissue. The results obtained were evaluated more accurately exposure rates and consequently absorbed doses near radioactive patients and allow for more effective radiological protection procedures for patient release criteria. The radiation exposure varied from patient to patient at same radioactivity administered due to patient’s gland size, age and statues of renal function that contributes in biological halflife of I-131. For all results obtained from patients treated with 5 mCi, 10 mCi, 15 mCi, 20 mCi, 25 mCi, 28 mCi, 29 mCi, 30 mCi, 100 mCi, 150 mCi, 200 mCi and 250 mCi were recorded and statistically analysed. It was concluded that patients treated with 15mCi to 30mCi should not be hospitalized and would be discharged with instructions. The patients treated with 30 mCi to 150 mCi quantities of radioactive I-131 should be hospitalized for a duration of (24 to 40) hrs after administration of radioactive I-131. The patients treated with 150 mCi to 250 mCi of radioactive I-131 should be hospitalized from (60 to 72) hrs after administration of radioactive I-131.