Estimation of Absorbed and Effective Doses in Organs through Computed Tomography Examinations Using Automatic Exposure Control and Fixed Tube Current Techniques: A Phantom Case Study

The study aimed to assess absorbed and effective doses in organs through computed tomography (CT) examinations using automatic exposure control (AEC) and fixed tube current (FTC) techniques.

Scanning parameters were obtained for routine adult CT examinations and used to estimate the organ absorbed and effective doses using CT-Expo software. The estimated effective doses were based on International Commission on Radiological Protection publication 103 recommendations.

Regarding the scans performed with AEC, doses to head, chest, abdomen and pelvic organs were within the range of 19.7-41.8, 6.4-17.4, 19.2-20.9, and 10.5-24.9 mGy respectively. Moreover, the effective doses for the mentioned organs were 1.6, 6.1, 6.4 and 5.4 mSv respectively. Considering FTC technique, doses to organs ranged 16.7-75.5, 4.1-52.2, 10.6-33.2 and 5.2-38.7 mGy respectively. Moreover, the mean effective doses of FTC were 2.1, 6.9, 9.4 and 6.1 mSv, respectively. Examinations performed with AEC technique induced a dose reduction of 9% and 34% for head organs, 52, 62 and 25% for chest organs, 16% and 14% for abdomen organs, and 11% and 10% for pelvic organs, compared to the FTC. A dose increase of 3% was observed for testes. The mean effective doses for scans with AEC were 13-46% lower than those obtained by FTC.

According to the obtained results of the current study, the estimated doses for scans with AEC technique were in a lower level compared to FTC technique. Accordingly, it is recommended to utilize this technique for CT examinations to ensure optimal dose reduction to radiosensitive organs.