Which component of the X-ray equipment is used to decrease the entrance skin dose of radiation?

The component of the X-ray equipment that is used to decrease the entrance skin dose of radiation is the filter. Filters are designed to absorb low-energy X-rays that do not contribute to image quality but increase the radiation dose to the patient. By incorporating filters into the X-ray system, the more harmful lower-energy photons are removed, allowing only higher-energy X-rays, which are more effective for imaging, to pass through. This process not only minimizes the radiation exposure to the patient's skin but also enhances the quality of the diagnostic image.

Collimators, while important for targeting the X-ray beam and reducing unnecessary radiation exposure to surrounding tissues, do not specifically reduce the entrance skin dose. Similarly, grids are used to improve image quality by reducing scatter radiation but do not directly affect the entrance skin dose. The X-ray tube itself generates the X-rays, but it does not play a role in filtering out lower-energy photons. Thus, the correct choice is the filter, as it specifically addresses the reduction of the entrance skin dose by eliminating non-contributory low-energy radiation.