Radioprotection No 59-1 | Page 52

46 S . Semghouli et al .: Radioprotection 2024 , 59 ( 1 ), 42 – 49

Table 5 . Benchmarking of the established Moroccan DRL in terms of DLP ( mGy . cm ) with international values .

in the five Moroccan university hospitals . The 75th percentile for abdomino-pelvic CT was lowest at UHC-1 and highest at UHC-2 . Interestingly , the university hospital had a significant impact on the 75th percentile of DLP . Differences in CT technology , scanning protocols and professionals ’ knowledge and practice of patient radiation protection contribute greatly to these variations ( Amaoui et al ., 2023 ; Ekpo et al ., 2018 ). On the other hand , tube current has a direct linear effect on radiation dose ( i . e . 50 % reduction in tube current results in 50 % reduction in associated dose ) and this may be the reason for the highest dose noted at UHC-2 among the five centers mentioned in this study ( Lira et al ., 2015 ). In addition , exposure parameters in terms of slice thickness and pitch differ considerably from one hospital to another , which may also explain the different results of CTDI , DLP and ED .

This study provides these DRLs are proposed as NDRLs for abdominopelvic CT examination in Morocco . All data included in this analysis were obtained using a multi-slice spiral CT scanner with an average tube potential of 120 kVp . The CT systems included in the current study differ in terms of technology and model , with the number of slices per rotation ranging from 16 to 64 . The DRL results for the centers studied were comparable , with the exception of the DRL noted at UHC-2 , which was very high . The results show large dose variations between UHC-2 and the other centers ( Tab . 4 ). Variations in CTDI vol and DLP for CT examinations between centers may be influenced by population characteristics , practice , technology , as well as examination protocol .

The proposed local DRLs for the five university hospitals in terms of DLP were between 551.56 mGy-cm ( UHC-1 ) and 2293.33 mGy-cm ( UHC-2 ) and 9.88 mGy ( UHC-5 ) and 46.40 mGy ( UHC-2 ) for CTDIvol ( Tab . 4 ). By comparing these results with those obtained in similar studies by El Fahssi et al .,

( in press ) who reported 444.51 mGy for DLP and 8.14 mGy for CTDIvol and by Benamar et al ., ( 2023 ) who found 517.1 mGy . cm for DLP and 11.3 mGy for CTDIvol , our findings showed a higher value for DLP and CTDIvol .

Table 5 summarizes a benchmarking between the DRL results obtained by this study and other DRLs established by various studies around the world . Comparing the NDRL≈773mGy established for the abdomino-pelvic procedure with that of other countries , Morocco demonstrated a dose significantly almost four times higher than that of Turkey ( 204 mGy ) and almost two and a half times smaller than that of Kenya ( 1842 mGy ). Lebanon , Japan , Kenya , Nigeria and Egypt showed an abdomen-pelvis CT dose 25 %, 29 %, 138 %, 92 % and 71 % higher than Morocco respectively ( Ekpo et al ., 2018 ). Whereas Italy , India and Turkey recorded an abdomenpelvis CT dose 55 %, 61 % and 279 % lower respectively than Morocco . However , this value remains comparable to those reported by the rest of the countries . A graphic illustration in Figure 1 clearly highlights this comparative approach . This further confirms the need to develop protocols and procedures as well as optimize CT examination practices in Morocco . The significant variations in dose within the same university hospital and between university hospitals in Morocco could be due to differences in CT machines technical platforms , the protocols and procedures used , the training levels of radiology technicians in terms of optimizing procedures and , above all , the non-assignment of medical physicists in radiology departments to date in Morocco .

During this investigation , we have analyzed data relating to abdominopelvic CT scan procedures from all UHCs in Morocco . Indeed , the Moroccan Agency for Nuclear and Radiological Safety and Security ( AMSSNuR ) is responsible for the regulation and control of activities involving sources of