Affiliations: [a] Department of Nuclear Engineering, School of Mechanical Engineering, Shiraz University, Shiraz, Iran | [b] Medical Imaging Research Center, Shiraz University of Medical Sciences, Shiraz, Iran | [c] Nuclear Medicine and Molecular Imaging Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
Correspondence:
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Corresponding author: Banafsheh Zeinali-Rafsanjani, Medical imaging research center, Shiraz University of medical sciences, Shiraz, Iran. Tel.: +98 7136281464; E-mail:b.zeinali.r@gmail.com
Abstract: INTRODUCTION: Dose evaluation with two Monte Carlo codes using
patient specific voxel phantom is presented in this paper. We employ both
MCNPX and DOSXYZnrc to perform dosimetry for mathematical voxel phantoms
generated by our in-house developed voxel phantom generator and
EGSnrc/CTCreate respectively. MATERIAL AND METHOD: Our case study was a 2.5 × 2.4 × 2.4 cm3 tumor in the middle lobe of right lung of a male patient
exposed to 6MV parallel beam. In order to compare these Monte Carlo codes
with together gross tumor volume (GTV) and organ at risks (OAR) doses and
dose volume histograms (DVH) were calculated. RESULTS: Comparing the mean absorbed dose results (in Gy) from both
codes indicates that gross tumor volume, heart and spinal cord have 2% to
10% difference. The 10% difference between the codes were from the
spinal cord region where was not in the therapy beam and it just received
the scatter radiation. The dose volume DVH obtained from DOSXYZnrc results
demonstrate a milder slope compared with MCNPX DVHs. CONCLUSION: It was revealed that MCNPX has some advantages in
comparison to DOSXYZnrc, but it is important to consider that for equal
precision in voxel dosimetry calculation, DOSXYZnrc runs faster than MCNPX
and it is a great advantage.
Keywords: MCNPX, EGSnrc, voxel phantom, patient specific phantom, DOSXYZnrc, DVH
