Digital skeletal radiography. Reduction of absorbed dose by adaptation of exposure factors and image processing.

Abstract

The possibility to reduce the absorbed dose to the patient by increase of tube potential while maintaining the same exposure to the image plate and sufficient image quality in skeletal radiography has been investigated. Image processing parameters were adjusted to account for an increase in tube potential by 20 kV. Revision of image processing parameters was based on measurements with phantoms constructed to simulate the histogram shape recorded for clinical images. Image quality was evaluated both using image quality criteria and visual grading analysis. Energy imparted was calculated from measurement of the kerma-area-product. Energy imparted was reduced by 20-30% using the modified technique with increased kV. All images were considered of accurate quality for diagnosis and the difference in image quality score was marginal. There was, however, a significant shift towards lower grades for the "high kV" technique using visual grading analysis.