Image quality in mammography with special reference to anti-scatter grids and the magnification technique. 1986

B Nielsen, and G Fagerberg

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.

UI MeSH Term Description Entries
D008327 Mammography Radiographic examination of the breast. 3D-Mammography,Digital Breast Tomosynthesis,Digital Mammography,X-ray Breast Tomosynthesis,3D Mammography,3D-Mammographies,Breast Tomosyntheses, Digital,Breast Tomosyntheses, X-ray,Breast Tomosynthesis, Digital,Breast Tomosynthesis, X-ray,Digital Breast Tomosyntheses,Digital Mammographies,Mammographies,Mammographies, Digital,Mammography, Digital,X ray Breast Tomosynthesis,X-ray Breast Tomosyntheses
D011829 Radiation Dosage The amount of radiation energy that is deposited in a unit mass of material, such as tissues of plants or animal. In RADIOTHERAPY, radiation dosage is expressed in gray units (Gy). In RADIOLOGIC HEALTH, the dosage is expressed by the product of absorbed dose (Gy) and quality factor (a function of linear energy transfer), and is called radiation dose equivalent in sievert units (Sv). Sievert Units,Dosage, Radiation,Gray Units,Gy Radiation,Sv Radiation Dose Equivalent,Dosages, Radiation,Radiation Dosages,Units, Gray,Units, Sievert
D011835 Radiation Protection Methods and practices adopted to protect against RADIATION. Protection, Radiation
D011856 Radiographic Image Enhancement Improvement in the quality of an x-ray image by use of an intensifying screen, tube, or filter and by optimum exposure techniques. Digital processing methods are often employed. Digital Radiography,Image Enhancement, Radiographic,Radiography, Digital,Enhancement, Radiographic Image,Enhancements, Radiographic Image,Image Enhancements, Radiographic,Radiographic Image Enhancements
D011858 Radiographic Magnification Use of optic and geometric techniques to enhance radiographic image quality and interpretation. It includes use of microfocal X-ray tubes and intensifying fluoroscopic screens. Magnification, Radiographic,Magnifications, Radiographic,Radiographic Magnifications
D005260 Female Females
D006801 Humans Members of the species Homo sapiens. Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D012542 Scattering, Radiation The diversion of RADIATION (thermal, electromagnetic, or nuclear) from its original path as a result of interactions or collisions with atoms, molecules, or larger particles in the atmosphere or other media. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed) Radiation Scattering,Radiation Scatterings,Scatterings, Radiation
D014962 X-Ray Film A film base coated with an emulsion designed for use with x-rays. Film, X-Ray,Radiographic Film,Film, Radiographic,Xray Film,Film, X Ray,Film, Xray,Films, Radiographic,Films, X-Ray,Films, Xray,Radiographic Films,X Ray Film,X-Ray Films,Xray Films

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