Gonad dose variation among facilities is influenced by exposure factor selection, plus which of the following?

• A. 1 and 2
• B. 2 and 3
• C. 1, 2, and 3
• D. 1 and 3

Answer: (C)

Gonadal dose varies not just with the chosen exposure factors, but with several interacting elements that affect how much radiation actually reaches the gonads. The energy and amount of the beam are set by technique factors, but filtration changes the beam spectrum by removing low-energy photons that would otherwise contribute to dose without improving image quality. Field size and beam restriction determine how much of the body, including the gonads, is irradiated. If shielding is used—properly placed and effective—it can significantly reduce gonadal dose. Differences in any of these areas from one facility to another lead to the observed variation. Since all three types of factors can influence dose, considering them together explains why gonad dose varies across facilities, making all three contributors relevant.