As OID increases and SID remains constant, entrance skin exposure (ESE)
A)remains unchanged.
B)decreases.
C)increases.
D)none of the above

Question

Quizplus · Accepted Answer

As OID increases (the distance between the x-ray tube and the patient's skin), the beam diverges and spreads out, which increases the area of the radiation field. This increased area results in a decrease in the intensity of the beam at the skin. However, if the SID (source-to-image distance) remains constant, the ESE will increase as the beam intensity decreases. This is because the beam is reduced in intensity but is spread over a larger area, so the total dose to the skin is increased. Therefore, as OID increases and SID remains constant, the ESE will increase.

As OID Increases and SID Remains Constant, Entrance Skin Exposure