Which of the following is NOT a source of radiation exposure in radiology?

In radiology, the sources of radiation exposure include various entities that can deposit radiation in the environment or the patient. Among the options provided, environmental light is identified as not a source of radiation exposure in this context. Light itself, particularly in its visible spectrum, does not have the properties that contribute to radiation exposure as understood in radiological work.

Radiation exposure in radiology primarily arises from ionizing radiation, which can be emitted by patients (as in the case of radioactive tracers), the primary X-ray beam used during imaging, and scatter radiation caused by the interaction of the primary beam with objects in the environment or the patient's body. Ionizing radiation has enough energy to remove tightly bound electrons from atoms, which is crucial in imaging and therapeutic processes within radiology.

In contrast, environmental light not only does not fall into the category of ionizing radiation but is also fundamentally different as it affects visibility rather than contributing to the radiation dose received by individuals in a healthcare setting. Thus, environmental light does not pose a risk of radiation exposure in radiological practices.