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Pediatr Radiol. 2016 Aug;46(9):1234-40. doi: 10.1007/s00247-016-3604-0. Epub 2016 Apr 6.

How accurate is size-specific dose estimate in pediatric body CT examinations?

Author information

1
Department of Radiology, Riley Hospital for Children, 705 Riley Drive, Room 1053, Indianapolis, IN, 46202, USA. bkarmazy@iupui.edu.
2
Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA. bkarmazy@iupui.edu.
3
Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN, USA.
4
CT Clinical Science, Philips Healthcare, Highland Heights, OH, USA.
5
Department of Biostatistics, Indiana University School of Medicine, Indianapolis, IN, USA.
6
Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA.

Abstract

BACKGROUND:

Size-specific dose estimate is gaining increased acceptance as the preferred index of CT dose in children. However it was developed based on non-clinical data.

OBJECTIVE:

To compare the accuracy of size-specific dose estimate (SSDE) based on geometric and body weight measures in pediatric chest and abdomen CT scans, versus the more accurate [Formula: see text] (mean SSDE based on water-equivalent diameter).

MATERIALS AND METHODS:

We retrospectively identified 50 consecutive children (age <18 years) who underwent chest CT examination and 50 children who underwent abdomen CT. We measured anteroposterior diameter (DAP) and lateral diameter (DLAT) at the central slice (of scan length) of each patient and calculated DAP+LAT (anteroposterior diameter plus lateral diameter) and DED (effective diameter) for each patient. We calculated the following in each child: (1) SSDEs based on DAP, DLAT, DAP+LAT, DED, and body weight, and (2) SSDE based on software calculation of mean water-equivalent diameter ([Formula: see text] adopted standard within our study). We used intraclass correlation coefficient (ICC) and Bland-Altman analysis to compare agreement between the SSDEs and [Formula: see text].

RESULTS:

Gender and age distribution were similar between chest and abdomen CT groups; mean body weight was 37 kg for both groups, with ranges of 6-130 kg (chest) and 8-107 kg (abdomen). SSDEs had very strong agreement (ICC>0.9) with [Formula: see text]. SSDEs based on DLAT had 95% limits of agreement of up to 43% with [Formula: see text]. SSDEs based on other parameters (body weight, DAP, DAP+LAT, DED) had 95% limits of agreement of up to 25%.

CONCLUSION:

Differences between SSDEs calculated using various indications of patient size (geometric indices and patient weight) and the more accurate [Formula: see text] calculated using proprietary software were generally small, with the possible exception for lateral diameter, and provide acceptable dose estimates for body CT in children.

KEYWORDS:

Abdomen; Chest; Children; Computed tomography dose index volume; Size-specific dose estimate

PMID:
27053280
DOI:
10.1007/s00247-016-3604-0
[Indexed for MEDLINE]

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