Internal Dose Evaluation, Quality Assurance and Uncertainty Analysis

This chapter provides an overview of dose evaluation methods for assessing internal radiation exposure and highlights the importance of understanding uncertainties in dose calculations. It discusses three categories of dose calculation models: intake, systemic, and dosimetric, which describe the absorption, distribution, and excretion of radioactive materials within the body. The Medical Internal Radiation Dose (MIRD) and International Commission on Radiological Protection (ICRP) systems are widely used for dose calculations in occupational, environmental, and medical settings. It emphasizes the significance of these methods in understanding radiation exposure and its effects on the human body. Additionally, it focuses on quality assurance in internal dose assessment through intercomparison exercises and the development of guidelines. It discusses variations among practitioners in approaches and results and highlights the importance of harmonization. The International Atomic Energy Agency (IAEA) organized intercomparison exercises to evaluate the impact of harmonization guidelines, while the IDEAS project developed guidelines for the incorporation of monitoring data. The chapter emphasizes the need for consistency, standardization, and accuracy in internal dose assessment. Furthermore, it discusses the uncertainties in internal dose calculations. It identifies uncertainties related to measurement processes, characteristics of intake, and the biokinetic and dosimetric models used. Measurement uncertainties include radiation detection and data normalization, while intake uncertainties involve factors such as route, physical and chemical forms of radionuclides, and timing of intake events. Understanding and evaluating these uncertainties are essential for accurate dose estimation and reliable communication of results. Overall, the chapter provides insight into dose evaluation methods, quality assurance through intercomparison exercises and guidelines, and the importance of considering uncertainties in internal dose assessment.