en Radiation Biology Radiation Biology تحقيق بديع Original Research <div style="text-align: justify;">Background: In the tube current modulation (TCM) technique, tube current is changed dynamically during the scanning process. To quantify the effect of a dynamic tube current, a distinct calculator is needed to estimate the CT output radiation dose in terms of volume CT dose index (CTDI_vol) and individual patient dose in terms of size-specific dose estimate (SSDE). This study developed a specific calculator for CT scanning using the TCM technique. Materials and Methods: The tube current was extracted from the DICOM header for every slice, and averaged over the scan length. The water equivalent diameter (D_w) and SSDE values were calculated for each tube rotation. The software was retrospectively applied to 57 patients who had undergone abdominal and thoracic CT examinations using a multi-detector CT, the Somatom Emotion 6.&nbsp; Results: The differences between the calculated CTDI_vol and the CTDI_vol reported by the CT scanner were 4.4 &plusmn; 1.2% and 6.0 &plusmn; 2.0% for abdominal and thoracic examinations, respectively. The average tube current was found to be linearly correlated with D_w with R² values of 0.707 and 0.696 for abdominal and thoracic examinations, respectively. The average tube current was also linearly and strongly correlated with the SSDE with R² values of 0.941 and 0.887 for abdominal and thoracic examinations, respectively. Conclusion: Calculator for estimating CTDI_vol and SSDE specifically for TCM in CT scanning has been successfully developed. The difference between calculated CTDI_vol values using this calculator and reported CTDI_vol values were less than 10%.</div> Volume CT dose index (CTDIvol), size-specific dose estimate (SSDE), water equivalent diameter (Dw), tube current modulation (TCM). 289 297 http://ijrr.com/browse.php?a_code=A-10-1-728&slc_lang=en&sid=1 C. Anam anam@fisika.undip.ac.id 7900319475328460012347 7900319475328460012347 Yes Department of Physics, Faculty of Mathematics and Natural Sciences, Diponegoro University, Indonesia F. Haryanto 7900319475328460012348 7900319475328460012348 No Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Indonesia R. Widita 7900319475328460012349 7900319475328460012349 No Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Indonesia I. Arif 7900319475328460012350 7900319475328460012350 No Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Indonesia G. Dougherty 7900319475328460012351 7900319475328460012351 No Department of Applied Physics and Medical Imaging, California State University Channel Islands, Camarillo, CA 93012, USA D. McLean 7900319475328460012352 7900319475328460012352 No Department of Medical Physics and Radiation Engineering, The Canberra Hospital, Australia