Optimization of digital breast tomosynthesis using the taguchi method

Abstract

Optimization of scanning parameters of digital breast tomosynthesis (DBT) is in general highly complex mainly because of the incompleteness of the imaging problem of DBT. There are many parameters that can affect the image quality of DBT including the view distribution, scan angle coverage, exposure distribution, and tube voltage to name a few. Image reconstruction algorithm may also play an important role in determining the image quality. Under a constraint of fixed radiation dose to the patient, it is highly desirable to optimize those parameters to achieve the highest diagnostic utility of DBT for a given detection task. A design-of-experiment (DOE) is a statistical method widely used for optimizing industrial fabrication processes that involve many parameters. Although its theoretical rigor has been questioned and challenged, its practical utility has attracted many investigators in their optimization problems of research and development. In this work, we applied the L18 DOE method to optimize 4 scanning parameters and reconstruction algorithm. Mass and micro-calcification detection task were considered, and a simulation and CIRS phantom were used for the experiment. We successfully optimized the scanning parameters and reconstruction algorithm to first order by use of the DOE method. Three levels of each scanning parameters were realized through an orthogonal array totaling 18 experiments to be conducted. Total-variation minimization algorithm outperformed the Filtered Back Projection (FBP) and Projection-Onto-Convex-Sets(POCS) algorithm, and optimum level of each scanning parameter was determined. In the simulation study, the contrast-to-noise ration of mass ranged from 2.16 to 174 revealing the near-optimum condition out of those 15 experiment conditions. In the real experiment study, the full width at half maximum of a micro-calcification ranged from 1.21 to 7.70 revealing the near-optimum condition out of those 16 experimental conditions. The main eff...