Abnormal breast tissue imaging based on multi-energy x-ray

摘要

The dual or multi-energy x-ray technique facilitates to generate tissue-selective images, by exploiting tissue-specific energy dependence of x-ray attenuation. An abnormal breast is considered to be a mixture of adipose, glandular, and abnormal tissues, but three tissues cannot be selectively decomposed because the total attenuation of a tissue is represented by only two attenuation basis functions at diagnostic energy range. This paper presents a novel method to selectively represent abnormal breast tissue, using polyenergetic multi-energy x-ray. We show that an abnormal tissue can be revealed from the total thickness map, which is virtually constructed by assuming a healthy and compressed breast. Specifically, regression analysis is first performed using the multi-energy images of the prepared calibration phantom that consists of two basis materials. Total thickness map is then constructed by linearly combining thickness maps of basis materials, where the optimal weights for combination are determined so that the uniformity of total breast thickness is maximized. It is noted that the proposed method does not need accurate attenuation coefficients of breast tissues. Simulation results show that the proposed method dramatically improves the detectability of mass that is obscured by normal structures.