Dosimetric impact of voxel resolutions of computational human phantoms for external photon exposure

• Published in: Biomedical physics & engineering express Vol. 5; no. 6; pp. 65002 - 65010
• Main Authors: Lee, Choonsik, Badal, Andreu, Yeom, Yeon Soo, Griffin, Keith T, McMillan, Dayton
• Format: Journal Article
• Language: English
• Published: England IOP Publishing 23.09.2019
• Subjects: external photon exposure; mesh phantom; Monte Carlo; voxel phantom
• ISSN: 2057-1976; 2057-1976
• DOI: 10.1088/2057-1976/ab2850

Several research teams have developed computational phantoms in polygonal-mesh (PM) and/or Non-Uniform Rational B-Spline format, but it has not been systematically evaluated if the existing voxel phantoms are still dosimetrically valid. We created three voxel phantoms with the resolutions of 1,000, 125, and 1 mm3 and simulated the irradiation in antero-posterior geometry with photons of 0.1, 1, and 10 MeV using voxel Monte Carlo codes, and compared the energy deposition to their organs/tissues with the values from the original PM phantom using mesh Monte Carlo codes. The coefficient of variation in energy deposition overall showed about five-fold decrease as the voxel resolution increased but differences were mostly less than 5% for any voxel resolution. We conclude that PM phantoms and mesh Monte Carlo techniques may not be necessary for external photon exposure (0.1-10 MeV) and the existing voxel phantoms can provide enough dosimetric accuracy in those exposure conditions.