44 S . Semghouli et al .: Radioprotection 2024 , 59 ( 1 ), 42 – 49 Table 2 . Statistical variation within the sample . Parameter Mean Max Min ± SD
Age ( year ) |
50.96 |
92.00 |
19.00 |
15.05 |
Weight ( kg ) |
67.94 |
100.00 |
50.00 |
11.41 |
BMI ( kg / m 2 ) |
25.71 |
32.36 |
20.10 |
3.03 |
CTDIw ð mGy Þ ¼ 1 3 CTDI 100 ; c þ 2
3 CTDI 100 ; p ; ð1Þ
where C is the average dose at the centre and p the average dose at the periphery .
CTDIvolðmGyÞ ¼
CTDIw ð mGy Þ ; ð2Þ Pitch
DLPðmGy : cmÞ ¼ CTDIvolðmGyÞScanlength ; ð3Þ
ED ¼ DLP k ; ð4Þ
where k is the dose conversion coefficient of the abdominopelvic organ .
The national third quartile DLP for CT examinations of the abdomen-pelvis was calculated as the aggregation of data coming from the five university hospital centers then compared with international levels in 21 different countries .
2.3 Statistical analysis
All data were analyzed using Microsoft Excel ( MS 2010 ). CT scan data were analyzed using descriptive statistics . The mean DLP for CT scans of the abdomen and pelvis was calculated , and quantitative variables were expressed as mean and standard deviation .
3 Results
This study focused on the five university hospital centers ( UHCs ) in Morocco . The mission of UHC is to provide tertiary-level care , clinical teaching at university and postgraduate level in medicine and pharmacy , practical training of nursing staff and medical research and nursing care . Three different brands of CT were used in these hospitals ( Siemens Somatom , General Electric and Optima ), and all were multislices ( 16-64 ) ( Tab . 1 ).
3.1 Patients data
The study included 300 adult patients aged 19 to 92 , with weights ranging from 67.94 to 100 kg and a mean BMI of 25.71 kg / m 2 . Table 2 provides a statistical presentation of patient data on age , weight and body mass index ( BMI ).
3.2 Exposure and imaging parameters
Table 3 summarizes the descriptive statistics for exposure and imaging parameters . Exposure parameters for all abdominopelvic CT examinations in the five UHCs were set at an average of 120 kV for voltage ( with the exception of UHC-1 , where voltage ranged from 120 kV to 130 kV ). For the tube current , the highest was used at CHU-2 ( 218 mAs ), while the lowest was used at UHC-1 ( 127mAs ). In terms of pitch , the lowest average was recorded at UHC-3 ( 0.64 ) and the highest at UHC-2 ( 1.5 ). In addition , the highest average slice thickness was recorded at UHC-1 ( 13.84 ) and the lowest at UHC-3 ( 6.59 ).
3.3 Dose assessment
Table 4 shows the descriptive statistics for DLP , CTDI vol , and effective dose of abdominopelvic examination per university hospital center in Morocco . The average value of DLP ( 1443.04 mGy . cm ) in UHC-2 hospital was larger than those of the other four hospitals , which could be due to the higher average pitch used as well as the mAs encountered in this hospital . Furthermore , a significant difference was demonstrated by comparing the mean DLP of abdominopelvic CT between different Moroccan UHC ( p < 0.05 ). The effective doses ( ED ), for UHC-1 , UHC-2 , UHC-3 , UHC-4 and UHC-5 hospitals were estimated to be 8.27 , 34.40 , 10.64 , 12.65 and 15.89 mSv respectively . The estimated value for ED for UHC-2 hospital is two times higher than those of UHC-4 , UHC-5 , and three times higher than that of UHC-3 and four times higher than that of UHC-1 hospital .
A UHC in Morocco is the main health structure in the region . It serves patients from the region where it is located or from others in terms of diagnostic and therapeutic care . It is essential to keep in mind that in the total optimization procedure DRLs represent only a small part . For appropriate diagnostic or therapeutic radiological procedures performed in the local area , region or country where they are used , DRLs should be developed . The distributions ’ third quartile value defined on the aggregation of data coming from all regions is commonly utilized as National Diagnostic Reference Level ( NDRL ). Consequently , potentially unusual practices can be identified using NDRL while they aren ’ t ideal doses . DRLs can as well be set for a particular locality or region within a country or , in special circumstances , for multiple countries . For this study , the proposed national DRL for the abdominopelvic was defined as a single value for the 75th percentile on the aggregation of DLP and CTDI vol data from the five University hospital centers studied . The proposed National DRL for