A - Higher milliamperage (mA); Shorter time (seconds) 高mA，短时间
B - Higher kilovoltage (kVp); Same exposure time 高kVp，相同曝光时间
C - Lower milliamperage (mA); Shorter time (seconds) 低mA，短时间
D - Higher milliamperage (mA); Longer time (seconds) 高mA，长时间
E - Lower milliamperage (mA); Same exposure time 低mA，相同曝光时间