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Keywords:
Radioprotection / Radiation dose, Lung, CT, CT-Quantitative, Experimental investigations, Comparative studies, Technology assessment
Authors:
J. H. Kim, K. B. Lee; Seoul/KR
DOI:
10.1594/ecr2015/C-0891
Results
1.
Pattern of change in mAs according to types of topogram Scan data from topogram that has no information above shoulder level(shoulder cut) shows high mAs than that from normal topogram in 3 types of scanner.
In contrast to shoulder cut,
the usage of a topogram that has no information below lower lobes of lung(liver cut) decreases mAs compared with scan data using normal topogram in 3 types of scanner.
In two cases of scan data from abnormal topogram,
there are no significant change in mAs due to scan direction(Figure 4,5,6).
2.
The comparison of mAs on neck when using a topogram of shoulder level cut When we use a topogram of shoulder level cut,
each average mAs is 2.38 times to that of using normal topogram in GE scanner(112 mAs to 267 mAs),
5.75 times in Phillips scanner(65 mAs to 374 mAs),
2.27 times in Siemens scanner(138 mAs 314 mAs) when scan direction is cranio-caudal.
In caudo-cranial scan direction,
average mAs is 2.47 times to that of using normal topogram in GE scanner(104 mAs to 257 mAs),
6.82 times in Phillips scanner(56 to 382),
6.34 times in Siemens scanner(44 mAs to 279 mAs)(Table 1) 3.
The comparison of mAs on liver when using a topogram of liver level cut Using liver level cut topogram,
average mAs is 0.61 times to that of using normal topogram in GE scanner(190 mAs to 116 mAs),
0.73 times in Phillips scanner(191 mAs to 140),
0.70 times in Siemens scanner(119 mAs 84 mAs) when scan direction is cranio-caudal.
In caudo-cranial scan direction,
average mAs is 0.53 times to that of using normal topogram in GE scanner(191 mAs to 101 mAs),
0.68 times in Phillips scanner(204 mAs to 139 mAs),
0.54 times in Siemens scanner(151 mAs to 81 mAs)(Table 2).