Final answer:
The largest occupational dose in a Diagnostic Imaging department is primarily from fluoroscopy and CT scans, which use ionizing radiation to create images of internal body structures.
Step-by-step explanation:
The largest occupational dose in a Diagnostic Imaging (DI) department comes mainly from fluoroscopy and CT scans. These are two techniques that utilize ionizing radiation, which has enough energy to remove tightly bound electrons from atoms, thus creating ions. Fluoroscopy provides real-time imaging to guide procedures, while CT uses computer-processed combinations of X-ray measurements taken from different angles to produce cross-sectional images of specific areas of a scanned object.
Both of these diagnostic tools give higher doses of radiation compared to other methods in the medical imaging field. This is because they rely on the use of X-rays, which are a form of ionizing radiation known for their ability to penetrate the body to create images of internal structures. In contrast, other techniques, such as MRI (Magnetic Resonance Imaging) and ultrasound, do not use ionizing radiation and therefore present less radiation exposure risk to healthcare workers.