Monte Carlo simulations for 20 MV X-ray spectrum reconstruction of a linear induction accelerator

Abstract

To study the spectrum reconstruction of the 20 MV X-ray generated by the Dragon-I linear induction accelerator, the Monte Carlo method is applied to simulate the attenuations of the X-ray in the attenuators of different thicknesses and thus provide the transmission data. As is known, the spectrum estimation from transmission data is an ill-conditioned problem. The method based on iterative perturbations is employed to derive the X-ray spectra, where initial guesses are used to start the process. This algorithm takes into account not only the minimization of the differences between the measured and the calculated transmissions but also the smoothness feature of the spectrum function. In this work, various filter materials are put to use as the attenuator, and the condition for an accurate and robust solution of the X-ray spectrum calculation is demonstrated. The influences of the scattering photons within different intervals of emergence angle on the X-ray spectrum reconstruction are also analyzed.

Study on the effects of the diagnosis-related group system on cost control in gastric malignant tumor based on propensity score matching

“…The basic billing principle of the DRG reform is "no reimbursement for overspending, and the balance is retained." Therefore, this reform will focus on promoting the transformation of China's hospital operation model from focusing on revenue expansion to focusing on cost control and optimization, which will promote hospitals to standardize diagnosis and treatment, improve e ciency, and ensure quality and safety [14].…”