118 A. El Khatib et al.: Radioprotection 2026, 61( 2), 113 – 120
An important factor in this discrepancy observed is the data collection methodology. However, the sample included in this study was based in the majority of the CTA examination involving multiphasic protocols. In contrast, the majority of the previous studies doesn’ t describe the protocol used.
Regarding the Brain CTA protocol, the comparison of the LDRLs from this study with those from previous studies showed comparable results, except for the study by Zensen et al.( 2021). This discrepancy arises because the Brain CTA protocol in Zensen et al.( 2021) was calibrated using a 32 cm body phantom. It is well established that CTDI vol measured in a head phantom is higher than that in a 32 cm phantom under identical technical parameters. Additionally, the radiation dose is influenced by beam filtration( including added filtration and shaping filter), with the shaping filter having the most significant impact, this is why the selection of beam filtration and phantom type for a CT examination must be determined by the anatomical region( head or body) and the patient’ s size( large or small).
For carotids examinations, it is known that the DLP values are significantly influenced by the scan length and the number of series conducted within the same examination, with increases in these factors resulting in higher DLP values. In addition to different tube voltages was used in the current study set at 110 kV in the hospital D, 120 kV for the hospital C and A and 140 for the hospital B. however, Eller et al.( 2019) reported that Carotid CTA using the lowest available voltage( 70 kV) is feasible and reduce the CTDI vol by 22 %, DLP by 20 %, while maintaining the image quality 55. This is particularly important given that radiosensitive organs, such as the thyroid gland and eye lenses, are within the irradiated area. The combination of high kV with multiphasic protocol may be explain the discrepancies showed in terms of the DLP. Hospital A and B used 3 series in the 80 % of the examinations and 3 in 91 %, respectively, and Treier et al.( 2010) used an examination consisting of a native phase followed by a contrast agent phase.
In the context of the CTPA and abdominal aorta protocol, the parameters used are not detailed in comparable studies, except for Harun et al.( 2020) and Salama et al.( 2017). Harun et al.( 2020) used the kV settings manually with a low pitch protocol of 0.798 and a single-phase technique. Salama et al.( 2017) used a combination of 120 kV and low pitch set at 1. Conversely, our study implemented a combination of high pitch and multiphasic protocols. Research indicates that high pitch protocols in CT imaging significantly affect the CTDI vol, with potential reductions in radiation dose by up to 48 %( Atlı et al. 2018) and 68 %( Ismail et al. 2017).
Regarding the protocol for lower limb examinations, the observed differences may be attributed to several factors. The use of non-optimized protocols, particularly the deactivation of the ATCM technique in 22 % of the protocols, likely contributed to these higher values.
5 Conclusion
This study establishes the first national DRLs for CTA in Morocco, revealing significant variations in CTDIvol and DLP across hospitals and protocols. LDRLs varied significantly, with Hospital D having the lowest DRLs due to optimized practices and Hospital B having the highest due to more scan phases. Moroccan LDRLs were generally lower in CTDIvol but higher in DLP compared to international studies, a discrepancy attributed to specific protocols and longer scan ranges. The findings underscore the need for protocol optimization to align doses with international standards and set a foundation for future research to refine these benchmarks.
Funding
This research did not receive any specific funding.
Conflicts of interest
The authors declare that they have no conflict of interest.
Data availability statement
Data in this article are not publicly available due to confidentiality and privacy restrictions, authors can provide necessary information or clarification upon personal request.
Author contribution statement
All authors contributed to the design and implementation of the research, to the analysis of the results and to the writing of the manuscript.
Ethics approval
This study did not carry out activities that would require approval by a research ethics committee.
Informed consent
This article does not contain any studies involving human subjects.
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