Non-Monte Carlo Methods for Investigating the Application of Coded Aperture Breast Tumour Imaging

Abstract

This is a continuous investigation of a possible application of Coded Aperture (CA) for breast tumor imaging. This image formation system allows a high photon transmission, image magnification and to a lesser extent provide (limited-angle) tomographic capability. This paper describes two non-Monte Carlo methods, the first one based on a simple attractive approach called Binary Mask Shift (BMS) representing the action of a distributed source in the projective CA imaging geometry. It allows to investigate all the possible built in artefacts without the effect of solid angle. Thus, it provides understanding of the application of CA patterns in breast tumor imaging through the evaluation of their potential and their performance under a variety of imaging conditions. The second method based on Pseudo-Ray Tracing (PRT) that obtained by purely calculating the angle of incidence of each point in the object that successfully strikes an open aperture element and then hits the detector element. These methods particularly used for CA imaging investigations. Interestingly, these methods yield similar results of a similar CA pattern but takes less computing power, than using a full Monte Carlo Simulation (MCS) approach. The main results demonstrate that Modified Uniformly Redundant Arrays (MURAs) patterns of squares arrays are very promising as it produces excellent decoded images. This is attractive particularly when used for breast tumor imaging i.e. ideal for imaging small isolated sources and thus provides a good match to the imaging of Scintimammography (SM).