[Investigation of practical method for quality assurance and control of medical displays].

Quality assurance (QA) guidelines for medical display systems in Japan, JESRA X-0093, were published in August 2005 and have been used in many medical fields to maintain image quality on medical displays. This report offers detailed explanations of terms and testing methodologies in the guidelines, taking into account users with little knowledge of display technology. The management grade classifications, luminance meters, test patterns, and evaluation methods for executing the QA are supplementally described based on the technical background of related things. In addition, the validity of the evaluation methods and judgment criteria for uniformity and contrast response tests were examined in some experiments. The experimental results of the contrast response indicated that some cases presented inadequate display contrast even if the contrast responses were set within ± 15% of the standard acceptable range for grade 1. The luminance responses of displays used in two computed tomography systems (CTs) and one magnetic resonance imaging system (MRI) were also measured, and the results indicated that their responses with conventional gamma responses were problematic for comparing images with those of medical displays.

[Report on the 89th Scientific Assembly and Annual Meeting of the Radiological Society of North America--micro-focus x-ray CT imaging of breast specimens with microcalcifications].

LEARNING OBJECTIVES: (1)Understand images of breast specimens with microcalcifications obtained by use of micro-focus CT. (2)Learn the relationship between mammographic features, pathologic characteristics, and micro-focus CT images. (3)Learn the usefulness of three-dimensional images in understanding of detailed structures and patterns of microcalcifications without cutting the specimen. ABSTRACT: Microcalcifications are one of the important sign for early detection of breast cancer by use of mammography, and has resulted in the detection of nonpalpable cancer. However, it is difficult to distinguish between benign and malignant microcalcifications, thus causing high false-positive rate. Micro-focus CT employs a x-ray tube of a focal spot size less than 10 microns, and has high spatial resolution, thus resulting in more accurate visualization of structures of microcalcifications. We investigated the relationship between micro-focus CT images of breast specimens with microcalcifications, mammographic features and pathologic characteristics. Micro-focus CT imaging was comparable to pathologic images in terms of resolution and contrast. Microcalcifications were more clearly detected in micro-focus CT imaging than specimen radiographs. Three-dimensional imaging on microcalcifications provided a tool for studying the shape and distribution of calcifications. Micro-focus CT for breast imaging was very useful for understanding of structures and patterns of microcalcifications without cutting the specimen.