Relationships between patient size, dose and image noise under automatic tube current modulation systems

Sookpeng, S., Martin, C. J., Gentle, D. J. and Lopez Gonzalez, M. R. (2014) Relationships between patient size, dose and image noise under automatic tube current modulation systems. Journal of Radiological Protection, 34(1), pp. 103-123. (doi: 10.1088/0952-4746/34/1/103)

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Publisher's URL: http://dx.doi.org/10.1088/0952-4746/34/1/103

Abstract

Automatic tube current modulation (ATCM) systems are now used for the majority of CT scans. The principles of ATCM operation are different in CT scanners from different manufacturers. Toshiba and GE scanners base the current modulation on a target noise setting, while Philips and Siemens scanners use reference image and reference mAs concepts respectively. Knowledge of the relationships between patient size, dose and image noise are important for CT patient dose optimisation. In this study, the CT patient doses were surveyed for 14 CT scanners from four different CT scanner manufacturers. The patient cross sectional area, the tube current modulation and the image noise from the CT images were analysed using in-house software. The Toshiba and GE scanner results showed that noise levels are relatively constant but tube currents are dependent on patient size. As a result of this there is a wide range in tube current values across different patient sizes, and doses for large patients are significantly higher in these scanners. In contrast, in the Philips and Siemens scanners, tube currents are less dependent on patient size, the range in tube current is narrower, and the doses for larger patients are not as high. Image noise is more dependent on the patient size.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Martin, Dr Colin and Lopez Gonzalez, Dr Maria Del and Gentles, Mr David
Authors: Sookpeng, S., Martin, C. J., Gentle, D. J., and Lopez Gonzalez, M. R.
College/School:College of Medical Veterinary and Life Sciences > School of Psychology & Neuroscience
College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing
Journal Name:Journal of Radiological Protection
Journal Abbr.:J. Radiol. Prot.
Publisher:IOP Publishing
ISSN:0952-4746
ISSN (Online):1361-6498

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