A novel method for determining source spectrum/detector spectral response in X-ray imaging

Knowledge of the X-ray spectrum in diagnostic imaging is important for dose calculations and correction for beam-hardening artifacts. This work investigates the possibility of determining the X-ray source spectrum from transmission data of a known phantom. In addition to the design of the phantom, the novel aspect of this work is the application of the expectation-maximization method, widely used in tomographic image reconstruction, in solving the ill-posed problem of finding the X-ray spectrum from transmission data.