Reduced-dose magnification mammography

The technology of mammography. Misunderstood and underutilized

This article reviews milestones in the technological development of mammography since 1970. Mammography is particularly underutilized as a screening procedure for breast cancer and the reasons for its continued inappropriate and under use are explored. Although there are some known barriers to increased utilization among the female adult population, the majority of barriers reside within the domain of referring physicians. Remedies to address the low referral rates for screening mammography are outlined for federal agencies, radiology groups, mammography equipment companies, medical schools, and philanthropic groups. Until the developers of technological procedures such as mammography appreciate that the application of a technology and its appropriate utilization by professionals and the public are important to consider when the technology is developed, utilization rates may not do justice to the technology's potential.

Image quality in mammography with special reference to anti-scatter grids and the magnification technique

Some of the parameters determining image quality in mammography are analyzed: the effects of primary photon spectra, focal spot size and screen-film systems on spatial resolution are discussed as are scattered radiation, development temperature and absorbed dose. The parameters limiting spatial resolution and contrast are evaluated for the standard and magnification techniques. Methods of reducing scattered radiation to improve contrast are evaluated. Scatter to primary ratios for different scatter reducing methods are compared, using the physical quantity energy imparted. For the standard technique the spatial resolution has been found to be limited by the fluorescent screen. With magnification technique the focal spot is the weakest link for the spatial resolution. The contrast is mainly set by the amount of scatter using the standard technique considering the use of a low tube potential (approximately 25 kVp). Using the magnification technique the amount of scatter is so small, that the tube potential is the limiting factor. We have found the optimized standard mammographic technique to be achieved under the following conditions: 25 kVp, 0.3 to 0.6 mm focal spot, film-focus distance 500 mm, anti-scatter grid, developing temperature 36 to 38 degrees C and 4 minutes total processing time with the screen-film system we have used. In magnification technique an air gap of at least 20 mm is desired. With an FFD of about 500 mm this will give a magnification ratio of 1.8 to 2.0 and a 0.1 mm X 0.1 mm focus spot is mandatory. With this technique, it is necessary to use a faster screen-film system than that used in standard mammography.

Clinical diaphanography--its present perspective

The application of nonionizing radiations and magnetism in clinical medical diagnosis has been rapidly increasing. The incorporation of these techniques into the armamentarium of the diagnostic roentgenologist warrants a change in nonmenclature to diagnostic imageologists. This review of the clinical applications of diaphanography covers the period of simple light source examination of the 1930s to the present sophisticated imaging with infrared film or videcon T.V. computerized format. Light physics of the infrared spectrum is well known, however experimental data of the mechanism of transillumination or normal and abnormal breasts are being investigated. A short discussion of breast anatomy and pathology including benign and malignant is basic to the clinical evaluation technique. A realistic appraisal of the application, the limitations of the technique and the current ongoing investigative studies in the European and American literatures are reviewed. Other noninvasive breast diagnostic techniques of thermography, ultrasound, and NMR are included as well as mammography in the diagnosis of breast disease and cancer.