Patient specific doses used to analyse the optimum dose delivery in barium enema examinations

The exposure and geometrical data for 89 barium enema examination patients were recorded manually in five hospitals in Finland. From the recorded data, organ and primary exit doses as well as effective individual doses were calculated for each patient using the ODS-60 program, which is capable of adjusting the calculation phantom according to a patient's size and sex. The mean (and standard deviation, SD) and median effective individual doses for the patients were 9.3 (5.7) and 6.8 mSv, respectively. Conversion functions from dose-area product to relevant organ doses and to effective individual dose were presented as a function of patient sex and weight. Mean primary exit dose values were calculated for each exposure. These were used to compare a theoretically justified exposure control (EC) function with the function of the automatic exposure (rate) control, AEC (AERC), at different hospitals. According to the analysis of primary exit doses, the implementation of the EC was far from optimum. With EC function proposed in this study the SD of effective individual doses to patients could be lowered considerably.