Optimization of tungsten x-ray spectra for digital mammography: a comparison of model to experiment

摘要: Tungsten (W) target x-rays tubes are being studied for use in digital mammography to improve x-ray flux, reduce noise and increase tube heat capacity. A parametric model was developed evaluate optimization of spectra a particular sensor. The computes mean glandular doses (MGD) combinations W target, beam filters, kVp, breast type thickness. Two figures merit were defined: (signal/noise)2/MGD spectral quantum efficiency; these computed as means approach object contrast. is derived from combination classic equations, XCOM NBS, published data. X-ray calculated measured filters Al, Sn, Rh, Mo Ag on Eureka tube. (Signal/noise)2/MGD filtered camera employing CsI scintillator optically coupled CCD which the detective efficiency (DQE) known. 3-mm thick acrylic disk imaged thickness 3-8 cm results compared predictions model. relative error between predicted +/- 2 percent 24 34 kVp. Calculated MGD function thickness, half-value layer filter compares very well Best performance found following combinations: with 30 mm breast, 45 mm, Sn 60 Al 75 breast. agrees measurement provides explore optimum kVp filter. For detector, this data may be used DQE estimate total system signal-to-noise ratio imaging task.© (1997) COPYRIGHT SPIE--The International Society Optical Engineering. Downloading abstract permitted personal only.