Effect of equalization filters on measurements with kerma‐area product meter in a cardiovascular angiography system

PURPOSE: This study aimed to evaluate the effect of equalization filters (EFs) on the kerma‐area product ([Formula: see text]) and incident air‐kerma ([Formula: see text]) using a kerma‐area product (KAP) meter. In addition, potential underestimations of the [Formula: see text] values by EFs were identified. MATERIALS AND METHODS: A portable flat‐panel detector (FPD) was placed to measure the X‐ray beam area (A) and EFs dimension at patient entrance reference point (PERP). Afterward, a 6‐cm(3) external ionization chamber was placed to measure incident air‐kerma ([Formula: see text]) at PERP instead of the portable FPD. KAP reading and [Formula: see text] were simultaneously measured at several X‐ray beam qualities with and without EFs. The X‐ray beam quality correction factor by KAP meter ([Formula: see text]) was calculated by A, [Formula: see text] and KAP reading to acquire the [Formula: see text] and [Formula: see text]. Upon completion of the measurements, [Formula: see text] , [Formula: see text] , and [Formula: see text] were plotted as functions of tube potential, spectral filter, and EFs dimension. Moreover, [Formula: see text] values were calculated to evaluate the [Formula: see text] underestimation. RESULTS: The [Formula: see text] values increased with an increase in the X‐ray tube potential and spectral filter, and the maximum [Formula: see text] was 1.18. [Formula: see text] and [Formula: see text] decreased as functions of EFs dimension, whereas [Formula: see text] was almost constant. [Formula: see text] decreased with an increase in EFs dimension but increased with an increase in tube potential and spectral filter, and the range was 0.55–1.01. CONCLUSIONS: [Formula: see text] value was up to approximately two times lower than the [Formula: see text] values by EFs. When using the [Formula: see text] value, the potential [Formula: see text] underestimation with EFs should be considered.