Risk Assessment and Application of Iaea Criteria in Determining the Need for Internal Exposure Monitoring of Radiation Workers at Institut Kanser Negara

Ionizing radiation exposure is divided into two categories that are external and internal exposure. The annual dose limit for the radiation workers is 20 mSv consists of internal and external exposure. Radiation workers in nuclear medicine are not only exposed to ionizing radiation externally but also internally. The widespread use of unsealed radioactive sources in nuclear medicine poses a potential for internal exposure of radiation workers in the field of nuclear medicine. External radiation monitoring using a dosimeter has been developed in Malaysia since 1985. However, assessment of the need for individual internal dose monitoring has not yet been developed in Malaysia. The purpose of this study is to assess occupational risk and to compare determination value of the need individual internal exposure monitoring of radiation workers in nuclear medicine department at Institut Kanser Negara (IKN). This study involves radiation workers at IKN by observation, survey forms and calculation of decision factor of the need for internal exposure monitoring based on IAEA dose criteria. The results show that the highest risk is during the use of radiopharmaceuticals for diagnosis and treatment of disease through inhalation process for lung scan as well as the preparation and oral administration to patient, especially radiopharmaceutical containing I-131 and I-124. In addition, a total of 12 out of 16 workers need internal monitoring involving biochemists, pharmacists, and technologists while physicist do not require internal monitoring. Overall,data obtained from this study is the first step in establishing a comprehensive internal exposure framework and promote to more effective and manageable radiation exposure monitoring.