EGS_cbct: Simulation of a fan beam CT and RMI phantom for measured HU verification
| Autor: | Freek C.P. du Plessis, Déte van Eeden |
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| Rok vydání: | 2016 |
| Předmět: |
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Tomography Scanners X-Ray Computed Monte Carlo method Biophysics General Physics and Astronomy Radiation Dosage Imaging phantom Collimated light Biophysical Phenomena 030218 nuclear medicine & medical imaging 03 medical and health sciences 0302 clinical medicine Optics Imaging Three-Dimensional Hounsfield scale Computer graphics (images) Humans Radiology Nuclear Medicine and imaging Computer Simulation Physics business.industry Phantoms Imaging Detector General Medicine Filter (video) 030220 oncology & carcinogenesis Radiographic Image Interpretation Computer-Assisted business Tomography X-Ray Computed Monte Carlo Method Beam (structure) Algorithms |
| Zdroj: | Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB). 32(10) |
| ISSN: | 1724-191X |
| Popis: | Introduction A mathematical 3D model of an existing computed tomography (CT) scanner was created and used in the EGSnrc-based BEAMnrc and egs_cbct Monte Carlo codes. Simulated transmission dose profiles of a RMI-465 phantom were analysed to verify Hounsfield numbers against measured data obtained from the CT scanner. Methods and materials The modelled CT unit is based on the design of a Toshiba Aquilion 16 LB CT scanner. As a first step, BEAMnrc simulated the X-ray tube, filters, and secondary collimation to obtain phase space data of the X-ray beam. A bowtie filter was included to create a more uniform beam intensity and to remove the beam hardening effects. In a second step the Interactive Data Language (IDL) code was used to build an EGSPHANT file that contained the RMI phantom which was used in egs_cbct simulations. After simulation a series of profiles were sampled from the detector model and the Feldkamp-Davis-Kress (FDK) algorithm was used to reconstruct transversal images. The results were tested against measured data obtained from CT scans. Results The egs_cbct code can be used for the simulation of a fan beam CT unit. The calculated bowtie filter ensured a uniform flux on the detectors. Good correlation between measured and simulated CT numbers was obtained. Conclusions In principle, Monte Carlo codes such as egs_cbct can model a fan beam CT unit. After reconstruction, the images contained Hounsfield values comparable to measured data. |
| Databáze: | OpenAIRE |
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