【評論主題】58.近年來上市之 lead-free apron 不含下列何種金屬？(A)錫（tin） (B)鎢（tungsten） (C)鉍（bismuth） (D)銅（copper）

【評論內容】Lead is not the only metal that protects you from an x-ray beam. These heavy metals may include barium, aluminum, tin, bismuth, tungsten and titanium. Non-lead aprons can be up to 40% lighter than standard lead aprons while still providing 0.50mm lead equivalency and 100% frontal protection at 100 kVp.