Methods of Measuring Radioactivity for Estimation of Intake

Direct counting methods that directly measure γ-rays coming from within the body or bioassay methods that measure the amount of radioactive materials in urine or feces are used to estimate the intake, which is required for calculating internal exposure doses.

Based on the results obtained using these methods, the time of intake of radionuclides, chemical forms, and intake routes (inhalation or ingestion) are taken into consideration and mathematical models (p.52 of Vol. 1, "Calculation of Internal Exposure Doses") are used to calculate the percentages of radioactive materials remaining in the body or found in body waste to determine the intake of respective radionuclides.

• Included in this reference material on March 31, 2013
• Updated on March 31, 2015