A.226鐳 B.137銫 C.59鈷 D.192依 E.125碘
60鈷治療機(jī)定時(shí)器誤差不大于()
A.1% B.2% C.3% D.2.5% E.1.5%
60鈷治療機(jī)照射野內(nèi)有用射線空氣比釋動熊率不對稱性應(yīng)小于()
A.5% B.10% C.15% D.20% E.60%