Catalogue of Diagnostic X-Ray Spectra and Other Data

Abstract

The original version of the Catalogue, SRS-30 published by Birch, Marshall and Ardan in 1979, contained essential data for physicists working in diagnostic radiology and mammography. The aim of this publication is to include and enhance much of the original data by providing a wider range of x-ray photon spectra. With the increased availability of desktop computing and the use of spectral data in computer modelling applications, the publication is also intended to provide the data in a more accessible form on CD-ROM. The compact disk contains a set of over 4000 data files and includes basic sets of unattenuated radiographic x-ray spectra from tungsten targets for tube potentials with sinusoidal waveform ripple and constant potential. Constant potential mammographic x-ray spectra from molybdenum and rhodium targets are also provided. The spectra have been calculated using the same theoretical method of Birch and Marshall but with up-to-date attenuation coefficients. All spectra have been provided at energy steps of 0.5 keV rather than at 1 keV intervals which were used in SRS-30. The attenuation coefficients are provided for various materials as are photon to kerma conversion factors for air, adipose tissue, skeletal muscle and bone. A useful tool provided on the CD-ROM is the Spectral Processor program. This allows spectral files to be processed and saved for future use. By selecting a spectral file and specifying the type and thickness of one of the displayed attenuating materials, calculations are made of the mean photon energy, the air kerma ( at 750 mm) and the first HVL of the filtered spectrum. A plot of the spectrum is also displayed. The spectral files may also be used as input to the user's personal computer programs. Other data provided on the CD-ROM include data for estimating x-ray tube filtration. The data in this set of files, when plotted, present HVL to total filtration graphs similar to those provided in Data for Estimating X-ray Tube Total Filtration (IPSM 64). One useful addition is that data are provided at target angles from to in increments rather than in steps of . Mammographic data for estimating x-ray tube filtration are also provided and include the data published in Commissioning and Routine Testing of Mammographic x-ray Systems (IPSM 59 [2nd edition]). The CD-ROM also contains explanatory text on what factors affect the spectrum shape, how the spectral data were calculated, how the data compare with SRS-30 and how the data should be used for estimating tube total filtration. A summary on how all the data are presented on the CD-ROM is also provided. A listing of a sample computer program for attenuating spectra is also included as an appendix. With its up-to-date spectral data, convenient data format and excellent on-line documentation, this publication will be a useful and effective tool for many scientists.