Monte Carlo design of optimal wire mesh collimator for breast tumor imaging process

Abstract

This paper presents the modeling of breast tumor imaging process using wire mesh collimator gamma camera. Previous studies showed that the wire mesh collimator has a potential to improve the sensitivity of the tumor detection. In this paper, we extend our research significantly, to find an optimal configuration of the wire mesh collimator specifically for semi-compressed breast tumor detection, by looking into four major factors: weight, sensitivity, spatial resolution and tumor contrast. The numbers of layers in the wire mesh collimator is varied to optimize the collimator design. The statistical variations of the results are studied by simulating multiple realizations for each experiment using different starting random numbers. All the simulation environments are modeled using Monte Carlo N-Particle Code (MCNP). The quality of the detection is measured directly by comparing the sensitivity, spatial resolution and tumor contrast of the images produced by the wire mesh collimator and benchmarked that with a standard multihole collimator. The proposed optimal configuration of the wire mesh collimator is optimized by selecting the number of layers in wire mesh collimator, where the tumor contrast shows a relatively comparable value to the multihole collimator, when it is tested with uniformly semi-compressed breast phantom. The wire mesh collimator showed higher number of sensitivity because of its loose arrangement while the spatial resolution of wire mesh collimator does not shows much different compared to the multihole collimator. With a relatively good tumor contrast and spatial resolution, and increased in sensitivity, a new proposed wire mesh collimator gives a significant improvement in the wire mesh collimator design for breast cancer imaging process. The proposed collimator configuration is reduced to 44.09% from the total multihole collimator weight.

Collimator for Variable Sensitivity and Spatial Resolution Without the Need for Exchange

“…The newly proposed multilayer collimator in high-resolution mode is similar to the wire-mesh collimator. As a result, this study is consistent with previous reports [7][8][9][10][11][12].…”

“…It is made from a series of wire grids [7][8][9][10][11][12]. Generally, a conventional collimator is overspecified in terms of its path length in the material composing the collimator [8].…”

“…Consequently, the aperture area is decreased by a factor of four. The septa in this mode have gaps similar to a wire-mesh collimator [7][8][9][10][11][12]. During use, the margin and sides of the collimator are shielded with a cover.…”

Simulation of intrinsic resolution of scintillation camera in Monte Carlo environment

“…This study is extension works that have been published in [6][7][8][9][10][11]. Previously, simulations have been done to determine the spatial resolution when a point source locates at various distances above the wire mesh collimator's top surface.…”

Impact of patient weight on tumor visibility based on human-shaped phantom simulation study in PET imaging system

“…We previously presented a report on the validation of this MCNP5 code and also algorithm developed in this study (Musarudin et al, 2013). In addition, MCNP5 code also had been used previously for single photon emission computed tomography and gamma camera modeling (Alnafea et al, 2006;Saripan et al, 2007Saripan et al, , 2009Saad et al, 2011;Roslan et al, 2010).…”