Program Information
Validation of a CT Monte Carlo Software
R Schmidt1*, J Wulff1 , P Penchev1 , K Zink1,2 , (1) Technische Hochschule Mittelhessen - University of Applied Sciences, Giessen, Germany, (2) University Medical Center Giessen and Marburg, Marburg, Germany
Presentations
TU-H-CAMPUS-IeP1-2 (Tuesday, August 2, 2016) 4:30 PM - 5:00 PM Room: ePoster Theater
Purpose: To validate the in-house developed CT Monte Carlo calculation tool GMctdospp against reference simulation sets provided by the AAPM in the new report 195.
Methods: Deposited energy was calculated in four segments (test 1) and two 10 cm long cylinders (test 2) inside a CTDI phantom (following case #4 of the AAPM report 195). The x-ray point source of a given 120 kVp spectrum was collimated to a fan beam with two thicknesses (10 mm, 80 mm) for a static and a rotational setup. In addition, a given chest geometry was used to calculate deposited energy in several organs for a 0° static and a rotational beam (following case #5 of the AAPM report 195). The results of GMctdospp were compared against the particular mean value of the four quoted Monte Carlo codes (EGSnrc, Geant 4, MCNP and Penelope).
Results: Calculated values showed no outliers in any of the cases. Differences between GMctdospp and the particular mean
Results: Calculated values showed no outliers in any of the cases. Differences between GMctdospp and the particular mean value were always at similar magnitude compared to the quoted codes. For case #4 (CTDI phantom) the relative differences were within 1.5 %, on average 0.4 % and for case #5 (chest phantom) within 2.5 % and on average 0.85 %.
Conclusion: The results confirmed an overall uncertainty of the Monte-Carlo calculation chain in GMctdospp being <2.5 %, for most cases even better. This can be considered small compared to other sources of uncertainties, e.g. virtual source and patient models. The photon transport implemented in GMctdospp inside a voxel-based patient geometry was successfully verified.
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