A Quantitative Analysis of Radiation-Induced Contamination Post-Iodine-131 Treatment for Thyroid Disease

Abstract

Objectives In Trinidad and Tobago, there is currently no legislation in place to protect patients, staff and the general public regarding the use of ionizing radiation and radioactive sources. One commonly used radioactive source is the isotope Iodine-131 ( 131 I) which plays a key role in the treatment of thyroid disorders and malignancies. This study aimed to investigate the contamination levels of patients, contact surfaces at their homes and solid waste accumulated post-administration of 131 I. The data obtained was used to assess relative risks associated with current practices and to determine if there is a need for the implementation of radiation isolation wards. Methods The homes of 19 patients were surveyed post-administration with the use of a calibrated Geiger Muller detector. The dose rate of the patients was measured from a distance of 1 m. Contact surfaces in the isolation area were measured together with the weight and exposure of the solid waste generated by the patients. Results 26% of patients had dose rates that were higher than the average international release criteria. All outpatients produced a total of 18.54 kg of contaminated solid waste with a total dose rate of 172.608 µSv/hr during the first 48-72 hours post-treatment. Conclusion It was determined that the highest relative risk was related primarily to the lack of monitoring of outpatients. It can be concluded that outpatient treatment with 131 I is safe in Trinidad and Tobago once the patients’ home is suitable for isolation and clear guidelines on radiation protection measures are discussed.