Format

Send to

Choose Destination
AJR Am J Roentgenol. 2017 Apr;208(4):862-867. doi: 10.2214/AJR.16.17316.

Follow-Up Study on Fetal CT Radiation Dose in Japan: Validating the Decrease in Radiation Dose.

Author information

1
1 Department of Radiology, National Center for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo 157-8535, Japan.
2
2 Department of Obstetrics and Gynecology, Hyogo College of Medicine, Hyogo, Japan.
3
3 Department of Obstetrics and Gynecology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
4
4 Department of Maternal and Fetal Medicine, Miyagi Children's Hospital, Miyagi, Japan.
5
5 Department of Advanced Fetal and Developmental Medicine, Tohoku University Graduate School of Medicine, Miyagi, Japan.
6
6 Department of Pediatric Imaging, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan.

Abstract

OBJECTIVE:

In 2011, we collected data on fetal CT radiation dose to determine the diagnostic reference level (DRL); however, continuous evaluation of the DRL is necessary. The hypothesis of this study is that the fetal CT radiation dose has decreased, and we predict a widespread use of iterative reconstruction (IR). We also predict that the national decrease in exposure is because of the DRL reported as a result of the previous national study.

MATERIALS AND METHODS:

Various testing protocols from each site were summarized as part of the study results. The minimum, one-fourth (25th percentile), median, three-fourths (75th percentile), and maximum values were obtained for volume CT dose index (CTDIvol), dose-length product (DLP), and scan length of 120 fetal CT examinations. The trends for IR usage and tube voltage were also investigated.

RESULTS:

Compared to the results of the 2011 study (n = 119), the minimum, 25th percentile, median, and 75th percentile values for CTDIvol and DLP have decreased for the tabulated results in 2015 (n = 120). The 75th percentile value for CTDIvol was 4.9 mGy, which is 43% of the previous value. IR was used in 70% of the sites. The radiation dose was significantly lower among groups that used IR.

CONCLUSION:

Four years passed between our initial survey on DRL and the present follow-up survey, and it appears that the previous report sufficiently fulfilled its objective and role in contributing to the decrease in DRL observed in this follow-up study.

KEYWORDS:

CT; diagnostic reference level; fetus; prenatal diagnosis; skeletal dysplasia

PMID:
28328259
DOI:
10.2214/AJR.16.17316
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Atypon
Loading ...
Support Center