超音波検査技術

The Japanese Society of Sonographers Superficial Organs Technical Committee developed a practical breast ultrasound phantom (hereafter, phantom) for practical training. The phantom reproduced the difficulty of scanning due to the shape and softness, and the interior part of the phantom was made up of multiple glandular lobes that look real by placing targets of mimic lesions, such as benign and malignant tumors and distorted architecture (Japanese Patent No. 6651164).

In 2018, we conducted four seminars using phantoms to provide lectures on the examination methods, practical techniques for scanning, and image interpretation to verify the effects of training.

The training effect was verified on 74 participants before and after the training based on (1) scanning time required for screening, (2) recording of a still image of the malignant tumor target, and (3) determination of the presence or absence of distortion in case videos. The results of the three tests were compared. (1) The scanning time was significantly shortened after the training (p＝0.002). (2) Three instructors evaluated the floating image of the probe, deviation in the target-rendering position, clarity of boundary, and quality of the selected image in three stages for the still image of the malignant tumor, and evaluation after the training was significantly improved (p＜0.0001). (3) The presence or absence of distortion was shown by changing the order of the same video before and after the course, and the sensitivity, specificity, and accuracy were significantly higher after the course (sensitivity, p＝0.032; specificity and accuracy, p＜0.0001).

Students also evaluated the phantoms better than the real ones. The results were as follows using the scale: similar 5 to dissimilar 1; surface hardness, 4.0; internal hardness, 4.0; nipple attenuation, 3.5; glandular lobe structure, 3.4; benign tumor, 4.5; malignant tumor, 4.2; segmental lesion, 3.9; and distortion, 3.7.