Measurements of breast tissue scattering properties have been made in an energy dispersive x-ray diffraction system over the momentum transfer range of 0.70 to 3.50 nm(-1). One hundred samples of excised tissue have been used. Results from the diffraction system have been compared with the histological analysis for each individual sample. It has been found that tissue types can be characterized on the basis of the shape of the scatter spectrum and on its relative intensity. The shapes are significantly different between tissue types in the range 1.0 to 1.8 nm(-1) and suggest that if particular values of momentum transfer are monitored, a discriminating signal could be obtained. Analysis of the maximum intensity in the signature also reveals a change of up to a factor of 2 between adipose and fat-free tissues.
The aim of this study was to assess the suitability of the Im'RT MatriXX 2D ion chamber array for performing verification measurements on the Varian Eclipse electron Monte Carlo (eMC) algorithm for a range of clinical energies (6, 12, and 20 MeV) on a Varian 2100iX linear accelerator. Firstly, the suitability of the MatriXX for measuring percentage depth doses (PDD) in water was assessed, including characterization of the inherent buildup found in the MatriXX. Secondly the suitability of the MatriXX for measuring dose distributions in homogeneous and heterogeneous phantoms was assessed using gamma analysis at 3%/3 mm. It was found that after adjusting the PDD curves for the inherent buildup, that the position of R50,normalD measured using the MatriXX agreed to within 1 mm to the PDDs generated using the eMC algorithm for all energies used in this study. Gamma analysis at 3%/3 mm showed very good agreement (>95%) for all cases in both homogeneous and heterogeneous phantoms. It was concluded that the Im'RT MatriXX is a suitable device for performing eMC verification and could potentially be used for routine energy checks of electron beams.PACS number(s): 87.55.km, 87.55.Qr
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