الفهرس 
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Abstract
History: The outbreak of pneumonia in Wuhan, China, in December 2019 quickly spread to other countries. The World Health Organization (WHO) identified the new coronavirus (COVID-19) as the main cause of the illness. The use of next-generation sequencing and real-time reverse transcription polymerase chain reaction (RT-PCR) techniques is ideal for the diagnosis of COVID-19. This method has a sensitivity of up to 71% and can be performed in respiratory tract specimens. High-resolution computed tomography (HRCT) is a type of imaging that can be performed on the lung to visualize the COVID-19 severity and early evaluation of its progress. The rapid emergence and evolution of HRCT have raised the possibility of dosimetric effects in patients. This is why low-dose CT protocols are recommended for those who are pregnant, pediatric, and follow-up patient disease prognosis.
Aim of work: The purpose of this research is to investigate the dosimetric effects of HRCT on COVID-19 patients from the perspective of effective dose, tissue dose, and cancer risk assessment using the International Commission on Radiological Protection (ICRP 103) 2007 guidelines.
Subjects & Methods: The study population included 100 adult patients from both genders who had undergone HCT. They were all diagnosed with COVID-19 infection. The positive test for COVID-19 was obtained from the real-time PCR test using the swabs collected from the patient’s mouths and throats. We used a Picture archiving and communication system (PACS) to collect and analyze patient demographic and anthropometric data from the dose report. The effective dose was calculated using the tissue conversion coefficient (k) for the chest CT and (VirtualDoseTM) CT software. The study looked into the different types of chest organs, such as the liver, breast, lungs, thyroid, colon, and stomach. Also, male and female reproductive organs were considered in this study. The estimated cancer risk incidence per 100,000 procedures was computed based on ICRP 103, 2007 with the primary focusing organ in this study being the breast, lung, stomach, and thyroid.
Results: In this study, female patients have significantly higher CTDIvol and CTDIw than male patients (p≤0.009) and (p≤0.009) respectively. The mean score of ED virtual was 8.57 mSv compared with the EDDLP which was 6.62 mSv. However, there is a significant difference between male and female patients in terms of ED virtual mean score (p=0.002). Also, there is a strong positive relationship between ED virtual and DLP (r= 0.741 p <0.001). The highest mean scores for equivalent doses among female patients were higher than male patients. Overall, the highest risk value found in the lung was in females compared with males. While the lowest cancer risk was found in the thyroid organ in males compared with females. The Pearson correlation showed that there are no significant relationships in cancer risk in the breast (p=0.166), cancer risk in the lung (p= 0.166), cancer risk stomach (p=0.166), and cancer risk thyroid (p=0.166) in between both genders in the terms of age.
Coclusion: we conclude that females have higher effective doses, organ doses, and cancer risk than males. The relationship between ED dose and BMI was non-linear while there was a strong positive relationship between ED virtual and DLP. Also, the highest and lowest cancer risk found to be in the lung and thyroid respectively. However, there are no significant relationships in cancer risk between both genders in the terms of age.