Radioprotection No 59-2 | Page 48

Z . Tahiri et al .: Radioprotection 2024 , 59 ( 2 ), 104 – 110 107
Table 4 . Technical specifications of the mammography units used . Manufacturer Unit number Model Anode / filter materials kV range mAs range System Type
General Electric
1
Senographe2000D
Mo , Rh
22 – 49
4 � 500
DR
Siemens
2
Mammomat 1000
Mo , Rh , W
22 � 35
2 � 560
CR
Planmed
3
Sophie Classic S
Mo , Rh
20 � 35
5 � 660
CR
Italray
4
Mammograph
Mo , Rh , W
20 � 35
1 � 640
CR
Siemens
5
Mammomat Select
Mo , Rh , W
22 � 35
1 � 500
CR
Table 5 . Median MGD and median breast thickness for each unit for the 2 views : CC and MLO .
Median MGD CC ( mGy )
Median MGD MLO ( mGy )
Median compressed breast thickness CC ( mm )
Unit 1
1.09 ± 0.45
1.26 ± 0.74
55.9 ± 1.01
56.2 ± 1.03
Unit 2
1.79 ± 0.09
2.04 ± 0.09
54.7 ± 0.12
56 ± 1.20
Unit 3
1.69 ± 0.03
1.73 ± 0.07
60.0 ± 0.15
61 ± 1.03
Unit 4
1.09 ± 0.08
1.18 ± 0.12
55.0 ± 0.29
55.2 ± 0.29
Unit 5
1.04 ± 0.37
1.22 ± 0.29
54.2 ± 0.20
54.7 ± 1.19
Median compressed breast thickness MLO ( mm ) Fig . 1 . Variation of MGD with compressed breast thickness for both views .
detection guide for breast and cervical cancer developed by the Lalla Salma Foundation for the Fight against Cancer and the Ministry of Health with support from the World Health Organization ( Ministère de la Santé du Maroc , 2011 ), with an average age of 57 years .
The overall median MGD dose between all units was 1.34 ± 0.36 mGy for CC and 1.48 ± 0.38 mGy for MLO , the median breast thickness was 55.92 ± 2.38 mm for CC and 56.62 ± 0.77 mm for MLO .
To highlight the observed variation in MGD between mammography units , we also reported the results for each of the individual system types included in this study . These data are presented in Table 5 . In general , the median MGD had a higher value for the MLO than for the CC view , with a few exceptions .
Fig . 2 . Median MGD ( mGy ) per unit for the complete protocol .
Unit 2 , although having a low compressed breast thickness , had a high median MGD per examination , 1.79 mGy for the CC view and 2.04 mGy for the MLO . Unit 3 had a MGD of 1.69 mGy for CC and 1.73 mGy for MLO with a median compressed breast thickness of 60.50 mm . The breast thicknesses collected at unit 5 were the lowest with a median of 54.45 mm and a median MGD of 1.13 mGy between the two views . The variation of dose with compressed breast thickness for the different mammography systems is shown in Figure 1 for the incidences , medial-lateral-oblique ( MLO ) and craniocaudal ( CC ), and the MGD for the entire protocol by each unit is shown in Figure 2 .
Finally , Table 6 summarizes the different acquisition parameters collected in this study .