Radiation Safety Practice Exam

Which technique directly measures ionizing radiation inside the living body?

1. In-vitro monitoring

2. Whole body counting

3. Counting body products

4. External beam assessment

The correct answer is: Whole body counting

Whole body counting is the technique that directly measures ionizing radiation inside the living body. This method involves the use of sensitive detectors, such as gamma spectrometers, to measure radioactivity emitted from radioactive substances that may have been ingested or inhaled by a person. The whole body counter typically captures the radiation emitted from the body as a whole, providing a comprehensive assessment of internal contamination with radioactive materials. This technique is particularly important in radiation safety and health physics because it helps to evaluate the internal dose that a person may have received from radioactive materials. By quantitatively measuring radiation from specific energy emitters within the body, whole body counting can assess the potential health risks associated with exposure and can inform medical decisions regarding treatment and monitoring. Other techniques mentioned, such as in-vitro monitoring, counting body products, and external beam assessment, do not provide a direct measurement of radiation from within the body. In-vitro monitoring involves analyzing samples taken from the body (like blood or urine), while counting body products relies on measuring radioactive substances in body excretions or products. External beam assessment pertains to measuring radiation exposure from outside the body, rather than from sources contained within the body itself.