Distance driven back projection image reconstruction in digital tomosysthesis

Abstract

In this paper, distance driven (DD) back projection image reconstruction was investigated for digital tomosysthesis. Digital tomosysthesis is an imaging technique to produce three dimensional information of the object with low radiation dosage. This paper is our new study of DD back projection for image reconstruction in digital tomosysthesis. Since DD considers that the image pixel and detector cell have width, the convolution operation is used to calculate DD coefficients. The approximation characteristics of some other methods such as ray driven method (RD) can be avoided. A computer simulation result of DD with Maximum Likelihood Expectation Maximization (MLEM) of tomosysthesis reconstruction algorithm was studied. The sequence of projection images were simulated with 25 projections and a total view angle of 48 degrees. DD with MLEM reconstruction results were demonstrated. Line profile along x direction was used to evaluate DD and RD methods. Compared with RD, the computation time in DD with MLEM to provide the reconstruction results was shorter, since the main loop of DD is over<i> x-y</i> plane intercepts, not over the image pixels or detectors cells. In clinical applications, both the accuracy and computation speed of implementation condition are necessary requirements. DD back projection may satisfy the required conditions.