Implementation of maximum-likelihood-expectation maximization method in Excel

Abstract

We implemented a maximum-likelihood-expectation maximization method that is an iterative reconstruction method using a spreadsheet computer program (Excel; Microsoft Corp.). The program comprises: 1) an introduction, 2) calculation of photon detection efficiency, 3) making projection, 4) iteration of computation, and 5) update of a reconstructed image. This program is devised for implementation of an ML-EM method algorithm that can be acquired efficiently. To verify the programAfs effectiveness from an education technology standpoint, a questionnaire investigation was conducted of students in the Department of Health Sciences. Results showed that the program is effective both for understanding the mathematical basis of the ML-EM method and for programming using C language. The program is useful for students or engineers who are interested in the principle and research of the computed tomography, or methods for depicting the human bodyAfs interior such as x-ray CT, MRI, SPECT, and PET.