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PHOTOTIMER CONSISTENCY TEST TOOL, MAMMOGRAPHY
Available in either acrylic or tissue-equivalent BR-12
material.*
Should be used to test thickness tracking.
The mammographic unit's Automatic Exposure Control should be capable of
maintaining optical density within ±0.15 OD as the voltage is varied from 25
to 35 kVp, and as breast thickness is varied from 2 to 8 cm for each technique.
Test images taken of uniform phantoms of varying thicknesses should not differ
by more than 0.30 OD from each other. These tests should be carried out over the
kVp range customarily used by the mammography center.
The Phototimer Consistency Test Tool is available in two materials--acrylic, and
for more accurate results, in breast tissue-equivalent BR-12 material. Both are
supplied in uniform 2.0 cm slabs to produce thicknesses of 2, 4, 6 and 8 cm.
*BR-12 is a designation (D. R. White, et al.) of certain epoxy resi
formulations which react to x-ray in the mammographic energy range (15-30 keV)
in the same manner as human tissue. The tissue-simulation properties for these
slabs are maximized at 20 keV (28 kVp ±). The glandular equivalency of this
material is 45% in the mammographic range.
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