Kilovoltage beam Monte Carlo dose calculations in submillimeter voxels for small animal radiotherapy
Abstract
PURPOSE: Small animal conformal radiotherapy (RT) is essential for preclinical cancer research studies and therefore various microRT systems have been recently designed. The aim of this paper is to efficiently calculate the dose delivered using our microRT system based on a microCT scanner with the Monte Carlo (MC) method and to compare the MC calculations to film measurements. METHODS: Doses from 2-30 mm diameter 120 kVp photon beams deposited in a solid water phantom with 0.2 x 0.2 x 0.2 mm3 voxels are calculated using the latest versions of the EGSnrc codes BEAMNRC and DOSXYZNRC. Two dose calculation approaches are studied: a two-step approach using phase-space files and direct dose calculation with BEAMNRC simulation sources. Due to the small beam size and submillimeter voxel size resulting in long calculation times, variance reduction techniques are studied. The optimum bremsstrahlung splitting number (NBRSPL in BEAMNRC) and the optimum DOSXYZNRC photon splitting (Nsplit) number are examined for both calculation approaches and various beam sizes. The dose calculation efficiencies and the required number of histories to achieve 1% statistical uncertainty--with no particle recycling--are evaluated for 2-30 mm beams. As a final step, film dose measurements are compared to MC calculated dose distributions. RESULTS: The optimum NBRSPL is approximately 1 x 10(6) for both dose calculation approaches. For the dose calculations with phase-space files, Nsplit varies only slightly…
Read the paper
Related studies
- Characterization and Analysis of Porosity and Pore Structures
- Practical considerations for conducting ecotoxicity test methods with manufactured nanomaterials: what have we learnt so far?
- Dental Optical Coherence Tomography
- Radiation-shielding concrete: A review of materials, performance, and the impact of radiation on concrete properties
- Testing entanglement of annihilation photons
- Calanus finmarchicus seasonal cycle and diapause in relation to gene expression, physiology, and endogenous clocks
Go deeper in Evidence Hub
Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.