Application of expectation maximization to x-ray spectrum estimation for medical accelerators from transmission data

Accurate computation of dose delivered to the patient depends on knowledge of the x-ray spectrum of therapy, x-ray beams. This work applies the expectation-maximization (EM) method to the problem of reconstructing the x-ray source spectrum from transmission data of Aluminum and Lead. The proposed EM method is compared to an algebraic approach for solving the corresponding linear system of equations.