Which factor is cited as the largest contribution to unnecessary patient radiation dose?

The largest contribution to unnecessary patient radiation dose is attributed to failure to collimate. Collimation is the practice of narrowing the beam of radiation to match the area of interest being imaged. When collimation is not done properly, the radiation beam can expose more tissue than necessary, leading to an increased dose of radiation to the patient. This can result in unnecessary radiation exposure to areas that are not being examined, which can increase the risk of potential radiogenic effects, such as cancer.

Proper collimation helps in concentrating the radiation on the region of interest, minimizing the scatter and exposure to surrounding tissues. It is a critical aspect of radiation safety and effective imaging technique. By ensuring that the radiation dose is limited to only the area of interest, healthcare providers can significantly reduce unnecessary radiation exposure and improve patient safety during radiological procedures.