Exposure Time Calculation
FormulaRearrangements of the fundamental relationship between mA, time and mAs.
t = mAs / mA
mA = mAs / t
mAs = mA × t
Useful for converting between technique settings at constant mAs, or for checking the maximum permissible times with AEC systems.
Example: 200 mAs at 400 mA → t = 200 / 400 = 0.5 s
200 mAs at 800 mA → t = 200 / 800 = 0.25 s
Go beyond the definition
With Rad Index you study with flashcards, browse all 147 full projections and the ALARA checklist — even offline, on the ward.
