Radiation Exposure Considerations in Radioiodine Therapy Cases

Abstract

This study was conducted to assess the external radiation exposure rates of patients undergoing iodine-131 (I-131) therapy and evaluate how well current practices align with radiation safety protocols, particularly at the National Radiotherapy Oncology and Nuclear Medicine Centre (NRONMC), Korle Bu Teaching Hospital. The study also verified whether the dose of I-131 administered to patients corresponded with the prescribed dose. These were necessary to identify possible gaps in protocol application and help minimize unnecessary radiation exposure to both the public and health professionals. A prospective cross-sectional design was used, with data collected from nineteen (19) patients made up of both inpatients (thyroid cancer cases) and outpatients (hyperthyroidism cases). Patient exposure rates were measured at specific time intervals post-administration using calibrated survey meters. Quality control tests—including linearity, accuracy, constancy, and geometry—were conducted on the dose calibrator prior to use to ensure measurement reliability. All QC tests passed within the internationally acceptable ±5% tolerance limit, validating the equipment for accurate dose measurement. Findings from the study revealed that while most patients were safely discharged, some had external exposure levels exceeding the recommended threshold of 30 μSv/h at discharge. Furthermore, although the majority of administered doses were within ±10% of the prescribed values, two patients exceeded this range with percentage differences of 19.5% and 27%, respectively. These discrepancies suggest the need for stricter monitoring of dose preparation and administration. In addition, while inpatients showed a predictable decrease in exposure over time, outpatients demonstrated inconsistent exposure patterns due to factors such as shared waiting areas and early discharge. The outcome of the study showed that although the centre has some safety measures in place, there are notable inconsistencies in practice and discharge decisions. The study concludes that there is a need for the development of localized and well-documented protocols to enhance consistency in patient management, especially for radiation exposure assessment and discharge criteria. It is recommended that routine QC checks be strictly enforced, patient isolation be improved, and staff training intensified to align with best practices and ensure optimal patient and public safety in I-131 therapy cases.