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Mammography vs conventional radiography technique factors

Two-column comparison. Mammography uses low tube voltage (about 25 to 32 kVp) giving a lower mean photon energy (about 17 to 23 keV) with molybdenum or rhodium and tungsten target and filter combinations, a small focal spot (about 0.1 to 0.3 mm), a short focus-to-image distance (about 60 to 65 cm), longer exposure times, an anti-scatter grid in contact views, and contrast driven by the photoelectric effect. General radiography uses 60 to 120 kVp, a harder beam, a tungsten target, a larger focal spot, a longer focus-to-image distance (about 100 to 115 cm), shorter exposures, and relatively more Compton scatter. The goal in mammography is high soft-tissue contrast and high spatial resolution to resolve microcalcifications.

Mammography versus general radiography technique factors Two-column comparison. Mammography uses low tube voltage (about 25 to 32 kVp) giving a lower mean photon energy (about 17 to 23 keV) with molybdenum or rhodium and tungsten target and filter combinations, a small focal spot (about 0.1 to 0.3 mm), a short focus-to-image distance (about 60 to 65 cm), longer exposure times, an anti-scatter grid in contact views, and contrast driven by the photoelectric effect. General radiography uses 60 to 120 kVp, a harder beam, a tungsten target, a larger focal spot, a longer focus-to-image distance (about 100 to 115 cm), shorter exposures, and relatively more Compton scatter. The goal in mammography is high soft-tissue contrast and high spatial resolution to resolve microcalcifications. Mammography vs general radiography: technique factors factor mammography general radiography tube voltage low, ~25–32 kVp ~60–120 kVp mean photon energy lower, ~17–23 keV higher (harder beam) target / filter Mo/Rh, Rh/Rh, W/Rh, W/Ag tungsten (W) focal spot small, ~0.1–0.3 mm (~0.1 mm for magnification) larger focus-to-image distance short, ~60–65 cm ~100–115 cm exposure time longer (low kVp, more mAs) shorter anti-scatter grid used in contact views (ratio ~4:1–5:1; omit for mag) used contrast mechanism photoelectric effect (∝ Z³/E³, strong at low keV) relatively more Compton Goal in mammography: high soft-tissue contrast (glandular vs adipose) via the low-energy, photoelectric-dominated beam, and high spatial resolution to resolve microcalcifications. Short focus-image distance offsets by inverse square law; compression / small focal spot limit unsharpness.
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