# Assessment of Imaging Protocol and Patients Radiation Exposure in Computed Tomography Colonography
## 3 Results and Discussion
Figure 3A shows optimum anatomical coverage while Figure 3B indicates poor choice of anatomical coverage. An increase of scan length due to the extension of the anatomical coverage beyond necessary increases the dose per procedure (DLP, mGy.cm), also the CTDI\({}_{\text{vol}}\) (mGy). Figure 1: (**A**): Direct relation between tube current (mA), the CTDI\({}_{\text{vol}}\) (mGy) and effective dose (mSv). CTDI\({}_{\text{vol}}\) (mGy) and effective dose (mSv) increase with tube current value. (ACR recommendation for the effective dose is 10 mSv) (According to AAPM, the range of CTDI\({}_{\text{vol}}\) for average patient size is 3–6 mGy). (**B**): The relationship between CTDIvol (mGy) and DLP (mGy.cm), a wide variation being seen in DLP value as CTDI\({}_{\text{vol}}\) increases. (According to AAPM, the CTDI\({}_{\text{vol}}\) value is 2–4 mGy for 50–70 kg, 3–6 mGy for 70–90 kg, and 5–9 mGy for 90–120 kg patients. Figure 3: **(A,B)** Two female patients with the same scan parameters have a 16.5% difference in the effective dose due to anatomical coverage. The yellow line shows the scan coverage, the green line is the first part for the colon, and the red line shows the colon’s last level. **(A)** is an optimum anatomical coverage and **(B)** is improper anatomical coverage. Figure 2: Patients with the same parameter factors in a supine position, the first three patients having optimum anatomical coverage while the last two patients less well indicated anatomical range coverage, accordingly registering greater effective dose. with ATCM up to 63% and a 66% for effective dose (mSv) and CTDIvol (mGy), respectively, in comparison with the low-dose CTC (LD-CTC) without significant deterioration in image quality and polyp detection was seen. In addition to that, the use of sinogram-affirmed iterative reconstruction (SAFIRE) and ATCM can reduce the patient doses below 1.0 mSv, while maintaining the diagnostic quality of CT image [18, 19, 23, 33, 34] (Table 5). Furthermore, [PERSON] et al. [35] reported a reduction of CTDIvol (mGy) up to 20% by reducing the tube potential (kVP) from 120 to 100 irrespective of the patient size with a slight decrease in image quality. The available dose reduction techniques can significantly reduce the risk of CRC procedure. However, it requires awareness and a skillful technologist. With CTC performed for screening purposes, patients or individuals may be subject to repeat radiation exposures, contributing to additional cancer induction probability. With the current effective dose value (11.57 mSv), the additional expected cancer risk is six health detriments per 10,000 CTC procedures. Thus careful justification and optimization of CTC procedure are recommended, in particular to avoid unnecessary radiogenic risk, while maintaining the benefit of the CTC procedure. Artificial intelligence (AI) can considerably assist in the automation of image acquisition and reduce the human factors regarding experience in selecting optimal exposure parameters and scan range based on visual sensors and the imaging protocol [36]. Thus, the optimal scanning parameters can significantly improve the scanning efficiency and reduce the unnecessary radiation exposure. In addition to that, currently, computed aided diagnosis (CAD) is used widely to obtain an accurate diagnosis, prognosis, and tracking of CRC [37]. Patient dose reduction can be achieved by selecting optimum exposure parameters and the use of ATCM by well-trained technologists. The current study provided a rigorous assessment of patient dose during CTC at KFMC, Riyadh, Saudi Arabia. However, there is still a limitation regarding the sample size due to a multi-center study's access issues at a national level to derive the national diagnostic reference level (DRL) for patient dose optimization.