Abstract
In order to apply ultrasonography for breast cancer screening, it is essential to maintain quality assurance (QA) and quality control (QC) of the ultrasonography scanner and probe. QA/QC for the ultrasonography system used in Japan has been examined based on guidelines issued by the Japan Association of Breast and Thyroid Sonology. The phantom for this ultrasonography system was produced in 2009 by Kyoto Kagaku Co., Ltd., and domestic unification of QA/QC in Japan is expected. In this paper, we introduce an objective QC/QA method for the ultrasonography system used in Japan and propose an automatic evaluation method for mass targets in the phantom. We produced an evaluation software package with visual C# (Microsoft Co.). We captured images of the phantom in movie format at 15 frames/s, and evaluated the images by dividing the movie into individual frames. To avoid any influence of the target edge and posterior echoes, the measurement region of the mass target was set at 80% and half of the upper region from the initial outline. The mass target was extracted in ten stages, and the average pixel value of each target was measured. Evaluation of 50 phantoms by the proposal technique showed that the phantom was evaluable. In addition, this technique was effective for detecting poor adjustment of the phantom.
