79. 直線加速器中產生X 光的路徑順序為? ① Primary collimator ② Flattening filter ③ Bending magnet ④ Ion chamber ⑤ Secondary collimator (A)①②③④⑤ (B)③①②④⑤ (C)③②①④⑤ (D)③②④①⑤