Abstract ID: 91 Image acquisition and material differentiation for Dual Energy Computed Tomography by Monte Carlo simulations

Abstract

Dual Energy Computed Tomography (DECT) is an innovative and developing technique that uses two different x-spectra to get material differentiation in diagnostic imaging [1] . As a different modality from standard CT, it requires specified phantoms for quality control. Currently, there are few phantoms specialized for DECT and its price is quite high. Therefore, the aim of this study is to simulate the CT images of a DECT phantom whose compounds are combination of thermoplastic materials that could be manufactured. The present work uses Phase Space Files (PSF) computed from PENELOPE/PenEasy Monte Carlo code as a validated X-ray source model to obtain DECT images. The simulation process is divided in two steps: the first one compute the PSFs for two different X-ray spectra and the second one simulate the radiation transport through the phantom and detectors. The particles stored in PSFs were used to compute the energy deposition in each detector after the interaction with the phantom. For each angular projection it was used one of the two PSF. As a result, two sinograms were obtained and two images were reconstructed, each one representing the attenuation properties of its respective spectrum [2] . The thermoplastic material combinations were obtained using a methodology developed by our group [3] . Differentiation characteristics of the DECT were determined for materials commonly used in clinical practice as uric acid, iodine and calcium. The results demonstrate the capabilities of DECT/MC simulation for improving material visualization and identification, development of dedicated phantoms and for educational purposes.