en Radiobiology Radiobiology تحقيق بديع Original Research <div style="text-align: justify;">Background: To identify the best time-interval for dual-source coronary computed tomography angiography (CCTA) with bolus tracking automatic trigger technique. Materials and Methods: 120 patients were randomly divided into four groups (A, B, C and D), with 30 patients in each group. Monitoring was begun 10 seconds after injection, and the monitoring time-intervals for groups A, B, C and D were 1.14, 1.47, 2.00 and 3.00 seconds, respectively. CCTA acquisition was triggered as the monitored concentration in the region of interest (ROI) exceeded 100 HU. The monitoring times, CT and dose length product (DLP) values of the four groups were compared statistically. The quality of recorded CCTA images was evaluated objectively, and the image quality of blood vessel segments was accessed subjectively. Results: there were no statistically significant differences in objective evaluations between the four groups (P>0.05). Subjective evaluation results showed no statistically significant differences between groups A (1.879&plusmn;0.042), B (1.876&plusmn;0.043) and C (1.881&plusmn;0.052). Group D showed the highest subjective score (2.923&plusmn;0.069), which was significantly different from groups A, B, and C (P<0.01). The monitoring times for groups A, B, C and D were 4.78&plusmn;2.37, 3.76&plusmn;1.39, 2.77&plusmn;0.99 and 2.38&plusmn;0.64, respectively; and the DLP values were 4.13&plusmn;2.22, 2.18&plusmn;0.80, 1.50&plusmn;0.51 and 1.48&plusmn;0.43 mGy&middot;cm, respectively. DLP increases with increased monitoring times. Conclusion: When performing dual-source CCTA, a monitoring time-interval of 2 seconds with trigger scanning technique is the best choice, since it effectively reduces the radiation dose while providing satisfactory images.</div> &nbsp; Dual source computed tomography, coronary computed tomography angiography, bolus tracking, radiation dose. 145 150 http://ijrr.com/browse.php?a_code=A-10-2188-74&slc_lang=en&sid=1 Y. Han 7900319475328460020841 7900319475328460020841 No Department of Radiology, Third Central Hospital of Tianjin, Tianjin, 300170, China T. Wang 7900319475328460020842 7900319475328460020842 No Department of Radiology, Third Central Hospital of Tianjin, Tianjin, 300170, China L. Lin 7900319475328460020843 7900319475328460020843 No School of Medical Imaging, Tianjin Medical University, Tianjin, 300110, China C. Yu 7900319475328460020844 7900319475328460020844 No Department of Radiology, Third Central Hospital of Tianjin, Tianjin, 300170, China R. Lv 7900319475328460020845 7900319475328460020845 No Department of Radiology, Third Central Hospital of Tianjin, Tianjin, 300170, China Z. Liu 7900319475328460020846 7900319475328460020846 No School of Medical Imaging, Tianjin Medical University, Tianjin, 300110, China T. Zhang 7900319475328460020847 7900319475328460020847 No School of Medical Imaging, Tianjin Medical University, Tianjin, 300110, China L. Han lhan@tmu.edu.cn 7900319475328460020848 7900319475328460020848 Yes School of Medical Imaging, Tianjin Medical University, Tianjin, 300110, China