Which factor does NOT typically determine the exposure time in fluoroscopy?

The factor that does not typically determine the exposure time in fluoroscopy is environmental conditions. Exposure time in fluoroscopy primarily relates to the technical parameters set by the operator to achieve optimal image quality and patient safety.

Image contrast settings influence the exposure time as they determine how the system adjusts the radiation dose to produce images with sufficient contrast. Patient motion also plays a crucial role, as increased motion can necessitate longer exposure times to capture a stable image or lead to repetitive frames being taken, thereby affecting overall exposure duration. Window leveling, on the other hand, is related to image processing and display rather than a decision-making parameter in setting exposure time, but it does interact with how the brightness and contrast of the images are represented.

Environmental conditions do not have a direct impact on exposure time decisions, as exposure time is more closely tied to the mechanisms of the imaging equipment and patient factors rather than external environmental factors.