en Medical Physics Medical Physics تحقيق بديع Original Research <div style="text-align: justify;">Background: Worldwide the computed tomography (CT) scanning is recognized as a high radiation dose modality. This article aimed to estimate the radiation dose reduction and radiogenic risks for adult patients undertaking abdominal CT examinations. Materials and Methods: A total of 128 patients were studied using 2, 4, 16 and 64 slice CT&nbsp;scanners. The patients were divided into two categories: the first category as control category (80 patients), and the other as optimisation category (48 patients). The optimisation protocol was based on decreasing the gantry rotation time. Results: In general, the faster gantry rotation times (0.7 s/rot and 0.5 s/rot) resulted in dose reduction while maintaining images noise within the acceptable range. After dose optimization, the overall cancer risk was reduced by 21%, 49%, 29%, and 16%, for the patients undergoing abdominal examinations on 2, 4, 16 and 64 slice CT&nbsp;scanners, respectively. Conclusion: The patient dose optimisation during CT abdomen was investigated. By lowering gantry rotation time, a radiation dose reduction of up to 30 % was achieved without compromising the diagnostic findings. Accordingly, the attention of all technologists necessary to take advantage of the dose reduction methods reported in this study.</div> Dose reduction, CT, virtual dose, abdomen. 223 230 http://ijrr.com/browse.php?a_code=A-10-2055-105&slc_lang=en&sid=1 M.K. Saeed mohamedrick@gmail.com 7900319475328460020039 7900319475328460020039 Yes Department of Radiological Sciences, Najran University, Najran, Saudi Arabia N. Tammam 7900319475328460020040 7900319475328460020040 No Physics Department, College of Sciences, Princess Nourah Bint Abdulrahman University, Riyadh,  Saudi Arabia   A. Sulieman 7900319475328460020041 7900319475328460020041 No Radiology and Medical Imaging Department, Prince Sattam bin Abdulaziz University, Alkharj, Saudi Arabia