Abstract
Purpose:Accurate values for Kerma‐Area‐Product (KAP) are needed for patient dosimetry and quality control for exams utilizing radiographic and/or fluoroscopic imaging. The KAP measured using a typical direct KAP meter built with parallel‐plate transmission ionization chamber is not precise and depends on the energy spectrum of diagnostic x‐rays. This study compared the accuracy and reproducibility of KAP derived from system parameters with values measured with a direct KAP meter.Methods:IEC tolerance for displayed KAP is specified up to ± 35% above 2.5 Gy‐cm2 and manufacturer's specifications are typically ± 25%. KAP values from the direct KAP meter drifts with time leading to replacement or re‐calibration. More precise and consistent KAP is achievable utilizing a database of known radiation output for various system parameters. The integrated KAP meter was removed from a radiography system. A total of 48 measurements of air kerma were acquired at x‐ray tube potential from 40 to 150 kVp with 10 kVp increment using ion chamber type external dosimeter at free‐in‐air geometry for four different types of filter combinations following the manufacturer's service procedure. These data were used to create updated correction factors that determine air kerma computationally for given system parameters. Results of calculated KAP were evaluated against results using a calibrated ion chamber based dosimeter and a computed radiography imaging plate to measure x‐ray field size.Results:The accuracy of calculated KAP from the system parameters was better within 4% deviation in all diagnostic x‐ray tube potentials tested from 50 to 140 kVp. In contrast, deviations of up to 25% were measured from KAP displayed from the direct KAP meter.Conclusion:The “calculated KAP” approach provides the nominal advantage of improved accuracy and precision of displayed KAP as well as reduced cost of calibrating or replacing integrated KAP meters.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
