Which projection generally reduces gonadal dose during pelvic radiography?

• A. AP
• B. PA
• C. AP oblique
• D. PA oblique

Answer: (B)

Maximizing distance between the gonads and the X-ray source while increasing tissue between them lowers gonadal dose. In a pelvic radiograph, a PA projection does this effectively because the beam enters from the posterior side and travels toward the anterior; the gonads are closer to the anterior body surface, so they are farther from the X-ray tube and receive less direct exposure, with additional attenuation from intervening tissues. The inverse square law means dose falls as distance from the source increases, helping protect these sensitive organs. An AP projection puts the gonads nearer the source, increasing exposure, and oblique positions don’t provide the same reliable dose reduction as a true PA view, though they may alter exposure somewhat.