In Coronary Computed Tomography-Angiography (CCTA) examination with relatively high dose in CT examination, we report the organ dose and the effective dose received at the time of radiography was evaluated. A thermoluminescence dosimeter (TLD) and a human body phantom were used to measure the actual measurement value. The TLD element was calibrated with a line quality equivalent to the effective energy of the CT apparatus used in our hospital. Thereafter, the TLD element was embedded in a human body phantom, each organ dose was measured, and the effective dose was calculated. The radiography conditions were conditions used in clinical using, and the radiographing range was the average value in the actual clinical range. Effective dose was calculated from Dose Length Product: DLP (mGy cm) and the value calculated by the conversion factor k factor of ICRP Publ.102 of display value. Next, each organ dose was calculated using simulation software under the same imaging conditions. We used WAZA-ARI v2 for simulation software. Each organ dose showed the largest difference between the phantom study and the simulated software among the organ doses of 1 mGy or more was a stomach about twice the difference. As a result of calculating Pearson's product moment correlation coefficient with the phantom study and simulation software, there was a positive correlation (r = 0.9009 P <.001). The effective dose was about 1.4 times between the phantom study and the simulation software, about twice the difference between the phantom study, the simulation software and the value obtained from the DLP using the chest conversion factor of k factor. There is a correlation between the phantom study and the simulation software in each organ dose. Regarding the effective dose, the difference between the phantom study and the simulation software is about 1.4 times, whereas the converted value using DLP and the k factor of the chest leads to an underestimation of about twice. CCTA examination was thought to require a conversion factor different from that of the chest.
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