The element used as target material in mammography is which of the following?: (A) Copper, (B) Tungsten, (C) Molybdenum, (D) Aluminum
Answer is C. Two target materials used for mammography are molybdenum (Z 42) and rhodium (Z 45), the former being the most common. Molybdenum has a K-edge at 20 keV and produces characteristic radiations at 17.4 and 19.6 keV. In order to achieve a more nearly monoenergetic beam, the emerging spectrum is filtered by the same material (Molybdenum, about 0.03 mm thick).