Detailed TCM function for each patient was obtained from projection data.

Differences from the reference ( detailed TCM) method were calculated based on organ dose estimates.

Results: Doses estimated using the longitudinal approximated TCM resulted in small differences from doses obtained using the detailed TCM function.

Monte Carlo based models of each scanner and patient model were developed that incorporated the detailed TCM function for each patient model.

Equivalence test was performed to compare the equivalence limit between each method (longitudinal approximated TCM and fixed tube current method) and the detailed TCM method.