18-238 mammography phototimer consistency test tool
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 made of breast-tissue equivalent BR-12 material and comes in uniform 2.0 cm slabs to produce thicknesses of 2, 4, 6, and 8 cm.