Effect of patient size on radiation dose for abdominal MDCT with automatic tube current modulation: phantom study

Schindera, Sebastian T; Nelson, Rendon C; Toth, Thomas L; Nguyen, Giao T; Toncheva, Greta I; DeLong, David M; Yoshizumi, Terry T (2008). Effect of patient size on radiation dose for abdominal MDCT with automatic tube current modulation: phantom study. AJR, American journal of roentgenology, 190(2), W100-5. Leesburg, Va.: American Roentgen Ray Society 10.2214/AJR.07.2891

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OBJECTIVE: The purpose of this study was to evaluate in a phantom study the effect of patient size on radiation dose for abdominal MDCT with automatic tube current modulation. MATERIALS AND METHODS: One or two 4-cm-thick circumferential layers of fat-equivalent material were added to the abdomen of an anthropomorphic phantom to simulate patients of three sizes: small (cross-sectional dimensions, 18 x 22 cm), average size (26 x 30 cm), and oversize (34 x 38 cm). Imaging was performed with a 64-MDCT scanner with combined z-axis and xy-axis tube current modulation according to two protocols: protocol A had a noise index of 12.5 H, and protocol B, 15.0 H. Radiation doses to three abdominal organs and the skin were assessed. Image noise also was measured. RESULTS: Despite increasing patient size, the image noise measured was similar for protocol A (range, 11.7-12.2 H) and protocol B (range, 13.9-14.8 H) (p > 0.05). With the two protocols, in comparison with the dose of the small patient, the abdominal organ doses of the average-sized patient and the oversized patient increased 161.5-190.6%and 426.9-528.1%, respectively (p < 0.001). The skin dose increased as much as 268.6% for the average-sized patient and 816.3% for the oversized patient compared with the small patient (p < 0.001). CONCLUSION: Oversized patients undergoing abdominal MDCT with tube current modulation receive significantly higher doses than do small patients. The noise index needs to be adjusted to the body habitus to ensure dose efficiency.

Item Type:	Journal Article (Original Article)
Division/Institute:	04 Faculty of Medicine > Department of Radiology, Neuroradiology and Nuclear Medicine (DRNN) > Institute of Diagnostic, Interventional and Paediatric Radiology
UniBE Contributor:	Schindera, Sebastian Tobias
ISSN:	0361-803X
ISBN:	18212190
Publisher:	American Roentgen Ray Society
Language:	English
Submitter:	Factscience Import
Date Deposited:	04 Oct 2013 14:54
Last Modified:	05 Dec 2022 14:16
Publisher DOI:	10.2214/AJR.07.2891
PubMed ID:	18212190
Web of Science ID:	000252932100039
URI:	https://boris.unibe.ch/id/eprint/23071 (FactScience: 38803)