What factor directly affects patient exposure during fluoroscopy without automatic exposure controls?

The factor that directly affects patient exposure during fluoroscopy without automatic exposure controls is tube current. Tube current, measured in milliamperes (mA), governs the number of X-rays produced by the fluoroscopy system during an examination. Higher tube current results in increased radiation output, which in turn raises patient exposure. Conversely, lower tube current leads to decreased radiation exposure; thus, it plays a crucial role in managing the dose patients receive during fluoroscopic procedures.

While table height, image size, and collimation width can influence various aspects of a fluoroscopic examination, they do not directly control the amount of radiation produced. Table height may affect patient positioning but does not change the radiation dose. Image size can alter receptor exposure but is more related to the magnification and image quality rather than the primary radiation dose. Collimation width, while important for reducing unnecessary exposure by limiting the radiation beam to just the area of interest, does not determine the radiation output itself. Therefore, tube current is the key factor in shaping the level of patient exposure in the absence of automatic exposure control systems.