Final answer:
A health professional in radiology must wear a film badge to measure their exposure to radioactivity. The badge helps monitor the amount of radiation received to ensure safety standards are maintained. It uses photographic film, which fogs up upon radiation exposure to indicate levels of radiation.
Step-by-step explanation:
The reason why a health professional working in radiology must wear a film badge is to measure exposure to radioactivity. A film badge contains photographic film, which is sensitive to radiation and gets fogged in its presence. The badge is typically placed between different absorbers to ascertain the penetrating ability and the amount of radiation exposure. The level of fogging indicates the amount of radiation the health professional has been exposed to, ensuring their safety by monitoring and limiting their exposure to harmful radiation.
Those especially trained in nuclear medicine and radiological procedures utilize such monitoring devices as part of essential safety precautions. More sensitive alternatives to film badges use crystals that detect radioactivity by recording emissions, but personal dosimeters like film badges remain a simple initial measure for detecting and keeping track of occupational exposure.