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Keywords:
Dosimetric comparison, Radiation safety, CT, Radioprotection / Radiation dose, Musculoskeletal spine
Authors:
A. Papachristodoulou1, N. Pliamis1, G. Volford2, R. Markó3, �. Papp3, K. Katsari4, R. Illing3, L. M. J. Best5; 1Thessaloniki/GR, 2Szeged/HU, 3Budapest/HU, 4Athens/GR, 5London/UK
DOI:
10.1594/ecr2016/C-2386
Results
CT dose evaluation:
Table 3 Comparison of mean CT doses between Scanner A and B t-test assuming unequal variances |
Parameters |
GE LightSpeed VCT 64sl.
(A)n = 60 |
GE LightSpeed VCT 64sl.
(B)n = 60 |
p |
CTDIvol (mGy) |
23.7 |
20.1 |
0.13 |
DLP (mGy.cm) |
309.1 |
473.4 |
0.01 |
Effective Dose (mSv) |
4.6 |
7.1 |
0.00 |
Based on the results demonstrated in Table 3,
the was no significant difference in CTDIvol,
meaning that the radiation dose per slice is comparable between the incremental and spiral scanning modes.
Scanner B DLP and Effective Dose values are significantly higher than Scanner A.
Inter-rater reliability evaluation
The Fleiss’ kappa scores on visualization,
pathology and localization for both scanners showed moderate to substantial agreement between the observers,
based on Landis and Koch interpretation criteria [7].
Image quality evaluation: ordinal regression
The image quality evaluation of the data from Scanner A and from Scanner B,
showed a significant difference in the visualization of structures (p<0.00),
with Scanner A data receiving a higher score.
The evaluation of pathology and localization did not have significant differences (p>0.05).
Ordinal regression was applied to further identify differences between the protocols and their effect on image quality.
Results presented in Table 4 show that DLP and criteria have no significant impact on the quality of the images.
Therefore,
the lowest dose values from Scanner A protocol compared to that of Scanner B,
do not have a negative impact on the image quality.
Table 4 Ordinal regression analysis
|
Parameter Estimates
|
|
Odds Ratio
|
Std.
Error
|
Wald
|
df
|
Sig.
|
95% Confidence Interval
|
Lower Bound
|
Upper Bound
|
Threshold
|
[VGC_Score = -2.00]
|
0,004993556
|
,630
|
70,817
|
1
|
,000
|
0,001
|
0,017
|
[VGC_Score = -1.00]
|
0,027202934
|
,354
|
103,486
|
1
|
,000
|
0,014
|
0,054
|
[VGC_Score = .00]
|
0,281482965
|
,267
|
22,514
|
1
|
,000
|
0,167
|
,475
|
Location
|
DLP
|
0,999882201
|
,000
|
,139
|
1
|
,710
|
,999
|
1,001
|
[Scanner=A]
|
1,661850216
|
,265
|
3,667
|
1
|
,055
|
,988
|
2,795
|
[Scanner=B]
|
1,318173713
|
,235
|
1,387
|
1
|
,239
|
,832
|
2,088
|
[Reference]
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0a
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0
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