Radioprotection No 59-1 | Page 51

S . Semghouli et al .: Radioprotection 2024 , 59 ( 1 ), 42 – 49 45
Table 3 . Summary of descriptive statistics for exposure and imaging parameters per Hospital . Hospital
UHC-1
UHC-2
UHC-3
UHC-4
UHC-5
Exposure and imaging parameters
Exam Parameter
kV
mAs
ST *( mm )
Pitch
Mean
120.33
127.07
13.84
1.26
Median
120.00
110.00
15.00
1.20
Range
120 – 130
35 – 341
5.00 – 15.00
0.5 – 1.75
Exam Parameter
kV
mAs
ST *( mm )
Pitch
Mean
120
218.58
10.25
1.5
Median
120
239.6
12.5
1.6
Range
120 – 120
87 – 317
5.00 – 12.50
0.75 – 1.75
Exam Parameter
kV
mAs
ST *( mm )
Pitch
Mean
120.00
210.68
6.59
0.64
Median
120.00
220.00
5.00
0.75
Range
120 – 120
170 – 230
5.00 – 10.00
0.50 – 0.75
Exam Parameter
kV
mAs
ST *( mm )
Pitch
Mean
120.00
157.53
9.54
0.82
Median
120.00
155.00
10.00
0.60
Range
120 – 120
120 – 200
6.00 – 12.50
0.60 – 1.25
Exam Parameter
kV
mAs
ST *( mm )
Pitch
Mean
120.00
167.86
11.31
1.20
Median
120.00
225.00
12.50
1.75
Range
120 – 120
105 – 225
10.00 – 12.5
0.60 – 1.75
Table 4 . National and local dosimetric parameters in terms of DLP , CTDI vol and ED . DLP ( mGy . cm ) CTDIvol ( mGy ) ED ( mSv )
Mean
75 °
Mean
75 °
Mean
UHC-1
568.60
551.56
10.55
11.05
8.27
UHC-2
1443.04
2293.33
28.99
46.40
34.40
UHC-3
622.06
709.02
11.69
13.14
10.64
UHC-4
677.40
843.52
9.87
12.01
12.65
UHC-5
710.63
1059.62
8.14
9.88
15.89
Moroccan DRLs
658.86
773.20
11.40
12.05
9.88
abdominopelvic scan CT was 773.20 mGy-cm and 12.05 mGy for DLP and CTDI vol , respectively .
4 Discussion
In the present study , a survey was carried out on radiation exposure during adult abdominopelvic CT examination in the five main university hospitals in Morocco , with the aim of establishing NDRL of this procedure . The survey allowed characterizing the radiation exposure of adult patients after abdominopelvic CT procedures , such as the mean and 75th percentile for DLP and effective dose . This information is an accurate representation of the state of abdominopelvic CT practices in Morocco . Dosimetric parameters were analyzed . Then benchmarked against the norm for 21 countries , the values established in this study ranked Morocco 10th among countries with the highest 75th percentile DLP value . These slightly high doses should draw the attention of CT practitioners and organizations such as the Moroccan Nuclear and Radiological Safety and Security Agency to investigate the causes and establish methods for optimizing protection to reduce unnecessary exposure .
This dose variability could be explained by differences in CT machine technology in terms of beam collimation and detector arrays . Another reason for this variability could be the use of different protocols by clinicians , and radiographers ’ adherence to CT parameters ( Potential Tube Current and Scan Time ) set by manufacturers for abdominopelvic CT scans without optimization according to clinical indications . In addition , some radiographers are unfamiliar with AC modulation functions , while others have not used them during scanning . Dose optimization , i . e . reducing the delivered dose while maintaining adequate image quality , can be achieved with AC modulation ( Livingstone et al ., 2010 ). Dose optimization is therefore always essential . Significant variability was observed in the DRL of abdomino-pelvic CT scans