Final answer:
The average glandular dose per breast during mammography is affected by breast compression, the half value layer (HVL) of the x-ray beam, and breast size and composition; thus, the correct answer is D. 1, 2, and 3.
Step-by-step explanation:
The factors affecting the average glandular dose per breast during mammography include the degree of breast compression, the half value layer (HVL) of the x-ray beam, and the breast size and composition. Therefore, the correct answer to the question is D. 1, 2, and 3.
Breast compression during mammography is important as it helps to spread out the tissue and reduce the thickness that the x-rays have to penetrate, therefore reducing the amount of radiation needed. The half value layer (HVL) is a measure of the x-ray beam's penetration ability; a higher HVL indicates that the beam can penetrate deeper tissues with less absorption, thus potentially changing the dose received. Finally, breast size and composition play a role because denser tissue, like that found in younger women’s breasts, requires more radiation to achieve the same level of image quality as compared to older women who typically have more fatty tissue, which provides more contrast with less radiation exposure.