| Popis: |
The tube voltage is one of the major factors affecting the image quality in X-ray imaging. It is in kilovolts range and usually called kVp, since it is measured as the peak value during X-ray production. The kVp determines the penetration and absorption characteristics of the X-ray photons in the tissue and contributes directly to image quality. The accuracy and precision of the kVp should be measured annually to be 5%. The most accurate and precise method would be measuring the tube voltage directly with a voltmeter. However, the cost of an equipment for measuring such a high voltage and the danger for the technician makes non-invasive kVp-meters the best alternative. In this work, a previsously designed and prototyped kVp-meter is redesigned and its accuracy and precision at higher voltages improved to below 1% throughout the measurement range. The design makes use of the dependency of the linear attenuation coefficient of metals on the energy of the incident photons, which are in turn related to kVp. |
