16.加馬攝影機進行SPECT取像時,相較於平行孔準直儀(parallel hole collimator),扇形柱準直儀
(fan-beam collimator)具有下列何種特性?
(A)影像橫切面照野(transaxial field)變小,長軸照野(axial field)變小
(B)影像橫切面照野(transaxial field)變大,長軸照野(axial field)變大
(C)影像橫切面照野(transaxial field)不變,長軸照野(axial field)變小
(D)影像橫切面照野(transaxial field)變小,長軸照野(axial field)不變