Fact or fiction: An analysis of the 10 kVp ‘rule’ in computed radiography

PurposeTo determine whether increasing the tube voltage by 10 kVp whilst reducing the tube current by 50% (10 kVp ‘rule’) produces similar perceptual image quality.Method391 matched pairs of anthropomorphic chest phantom X-ray images were produced on a computed radiography (CR) system. Five experienced clinicians graded the images using a 2 alternative forced choice comparison method. Based on acquisition parameters and dose area product (DAP) readings, effective dose (E) was calculated for all images using dose calculation software.ResultsPerceptual image quality scores prior to and following application of the 10 kVp ‘rule’ were found have no statistical difference (p > 0.1), indicating that the increase in kVp and reduction in mAs had limited impact on the perceptual image quality. In all cases E reduced, with an average 36% (s.d 7%) after the ‘rule’ had been applied (p < 0.001).ConclusionResults demonstrate that application of the 10 kVp ‘rule’ significantly reduces E, with no significant reduction in perceptual image quality. Further research should be conducted for a range of examinations using CR and digital radiography (DR) systems.