Volume 8, Issue 5 p. 640-645

Multisegmented ion chamber for CT scanner dosimetry

Marleen M. Moore

Marleen M. Moore

Department of Radiology, School of Medicine, University of Colorado Health Sciences Center, Denver, Colorado 80262

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Robert K. Cacak

Robert K. Cacak

Department of Radiology, School of Medicine, University of Colorado Health Sciences Center, Denver, Colorado 80262

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William R. Hendee

William R. Hendee

Department of Radiology, School of Medicine, University of Colorado Health Sciences Center, Denver, Colorado 80262

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First published: September 1981
Citations: 5

Abstract

A multisegmented, ionization chamber capable of determining dosimetric profiles from a CT scanner has been developed and tested. The chamber consists of a number of 2 mm wide electrically isolated segments from which ionization currents may be measured. Presented here are the performance characteristics of the chamber including energy response, dose linearity, and corrections for “cross talk” between segments. Sample dosimetric profiles are depicted for 3 and 6 mm nominal beam widths at two locations in a dosimetric phantom positioned in the x-ray beam of a fourth generation CT scanner. The results agree well with the conventional method of obtaining dosimetry measurements with TLD chips.