Which factor does NOT affect patient dose?

The correct answer, focal spot size, does not affect patient dose in the same way that other listed factors do. Patient dose is primarily influenced by the amount of radiation emitted during an X-ray procedure, which is significantly determined by kilovoltage and milliampere-seconds.

Kilovoltage affects the energy and penetrating power of the X-rays produced, which in turn impacts the dose received by the patient. Higher kilovoltage typically results in a higher patient dose due to increased penetration and potentially more scatter radiation.

Milliampere-seconds (mAs) dictate the quantity of X-ray photons produced during an exposure. A higher mAs results in a greater number of X-ray photons reaching the patient, thus increasing the dose.

Inherent filtration is the measure of any absorption of low-energy X-rays as they pass through the X-ray tube and its components before reaching the patient. It plays a role in shaping the quality of the beam and can affect dose levels. However, focal spot size primarily influences image resolution and sharpness rather than the quantity of radiation delivered to the patient.

Therefore, while kilovoltage, milliampere-seconds, and inherent filtration directly contribute to the patient dose, focal spot size is not a factor in the same