The methodology to measure μ(s) of homogeneous samples was quantitatively accurate. Simple WAXS models predicted the probabilities for specific x-ray scattering to occur from heterogeneous biopsies. The fat subtraction model can allow μ(s) signals of breast cancer and fibroglandular tissue to be compared without the effects of fat provided there is an independent measurement of the fat volume fraction ν(f). Future work will consist of devising a quantitative x-ray digital imaging method to estimate ν(f) in ex vivo breast samples.

The methodology to estimate ν¯fat in a ROI of a tissue sample via CCD x-ray imaging was quantitatively accurate. The WAXS fat subtraction model allowed μs of fibrous tissue to be obtained from a ROI which had some fat. The fat estimation method coupled with the WAXS models can be used to compare μs coefficients of fibroglandular and cancerous breast tissue.

Abstract. Wide-angle x-ray scatter (WAXS) could potentially be used to diagnose ductal carcinoma in situ (DCIS) in breast biopsies. The regions of interest were assumed to consist of fibroglandular tissue and epithelial cells and the model assumed that biopsies with DCIS would have a higher concentration of the latter. The scattered number of photons from a 2-mm diameter column of tissue was simulated using a 110-kV beam and selectively added in terms of momentum transfer. For a 1-min exposure, specificities and sensitivities of unity were obtained for biopsies 2-to 20-mm thick. The impact of sample and tumor cell layer thicknesses was studied. For example, a biopsy erroneously estimated to be 8 mm would be correctly diagnosed if its actual thickness was between 7.3 and 8.7 mm. An 8-mm thick malignant biopsy can be correctly diagnosed provided the malignant cell layer thickness is >0.96 mm. WAXS methods could become a diagnostic tool for DCIS within breast biopsies. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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A model based on singly scattered photons could potentially be of use to correct for scatter effects in breast CBCT applications. Consider a simple phantom consisting of a 14 cm diameter 10.5 cm long cylindrical 50:50 mixture of fibroglandular and fat tissue with 21 cylindrical segments embedded along its central axis. One group of segments were 2 mm in diameter with compositions 0:100, 20:80, 35:65, 50:50, 65:35, 80:20, and 100:0. The remaining two groups had diameters of 5 mm and 10 mm. In order to reduce the computational time required, GEANT4 was used to simulate a scatter profile for a single projection which was then utilized in generating the large number of unique projections required for CBCT reconstruction. The scatter model was applied in an attempt to correct the cupping artifact caused by x ray scatter in the reconstructed images. The model assumed a homogeneous 50:50 phantom. The SPR generated by the model near the phantom center was at most 8% below that simulated by GEANT4. The scatter corrected images showed an almost complete removal of the cupping artifact. This simple model shows considerable promise in correcting scatter, though more research is required to determine its validity in more realistic imaging tasks.