In radiographic practice, which item is primarily used to limit unnecessary radiation exposure?

The collimator is primarily used to limit unnecessary radiation exposure during radiographic practices by controlling the size and shape of the X-ray beam. This device allows the operator to focus the radiation only on the area of interest, reducing the dose of radiation that may scatter to surrounding tissues and areas that do not need to be imaged. By maximizing beam quality and directing it to the specific area being analyzed, the collimator helps ensure that patients and personnel are not exposed to excess radiation.

In contrast, radiographic films are used to capture images but do not inherently limit radiation exposure; they are rather a tool for detecting radiation. Lead aprons provide a level of protection for personnel and patients from scatter radiation but do not necessarily limit the radiation emitted from the source. Film viewers are designed for examining the developed radiographs, without any impact on the exposure process itself.