Mammography spectrum measurement using an x-ray diffraction device.
The use of a diffraction spectrometer developed by Deslattes for the determination of mammographic kV is extended to the measurement of accurate, relative x-ray spectra. Raw x-ray spectra (photon fluence versus energy) are determined by passing an x-ray beam through a bent quartz diffraction crystal, and the diffracted x-rays are detected by an x-ray intensifying screen coupled to a charge coupled device. Two nonlinear correction procedures, one operating on the energy axis and the other operating on the fluence axis, are described and performed on measured x-ray spectra. The corrected x-ray spectra are compared against tabulated x-ray spectra measured under nearly identical conditions. Results indicate that the current device is capable of producing accurate relative x-ray spectral measurements in the energy region from 12 keV to 40 keV, which represents most of the screen-film mammography energy range. Twelve keV is the low-energy cut-off, due to the design geometry of the device. The spectrometer was also used to determine the energy-dependent x-ray mass attenuation coefficients for aluminium, with excellent results in the 12-30 keV range. Additional utility of the device for accurately determining the attenuation characteristics of various normal and abnormal breast tissues and phantom substitutes is anticipated.
Department of Radiology, University of California, Davis, UC Davis Medical Center, Sacramento 95817, USA. jmboone@ucdavis.edu
J M
JM
Boone
T
T
Yu
A
A
Seibert
D055592:Biophysical Phenomena; D001703:Biophysics; D005260:Female; D006801:Humans; D008327:Mammography / Q000295:instrumentation* / Q000706:statistics & numerical data; D008962:Models, Theoretical; D013679:Technology, Radiologic / Q000295:instrumentation; D014961:X-Ray Diffraction / Q000295:instrumentation*