Abstract
Quality control of ultrasonographic equipment is important for maintaining the reliability of ultrasound examination of the breast. Ultrasonographic breast cancer screening requires a high degree of quality assurance. The present study was performed to evaluate the deterioration of breast ultrasonography equipment using pictures of a phantom manufactured by Kyoto Kagaku Co., taken monthly. Six institutions belonging to the Quality Control Research Group of the Japan Association of Breast and Thyroid Sonology were involved. Pictures of the phantom were taken periodically under the same conditions determined beforehand, and the images were compared with that obtained at the beginning. This allowed us to detect even a minimal degree of deterioration in the performance of the machine. Other problems remain to be solved, such as any deterioration in the phantom itself, and the length of its efficient working life. In addition, there are various aspects associated with clinical ultrasonographic breast examination such as proper focusing and the depth of the visual field, appropriate gain and dynamic range, visualizaion of each layer of the skin, the optimal echo level of subcutaneous fat tissue for evaluating internal structures, good contrast between subcutaneous fat tissue and breast tissue, detailed evaluation of structures within breast tissue, clear demonstration of the pectoralis major muscle, and so on.
