Collimator design for experimental minibeam radiation therapy.

Purpose: To design and optimize a minibeam collimator for minibeam radiation therapy studies using a 250 kVp x-ray machine as a simulated synchrotron source.

Methods: A Philips RT250 orthovoltage x-ray machine was modeled using the EGSnrc/BEAMnrc Monte Carlo software. The resulting machine model was coupled to a model of a minibeam collimator with a beam aperture of 1 mm.

The effects of dose calculation resolution on dose accuracy for radiation therapy treatments of the lung. Part II. A comparison of dose distributions from an explicit lung model to dose distributions derived from a CT representation.

Purpose: Due to limitations in computer memory and computation time, typical radiation therapy treatments are calculated with a voxel dimension on the order of several millimeters. The anatomy below this practical resolution is approximated as a homogeneous region uniform in atomic composition and density. The purpose of this article is to examine whether the exclusion of anatomic structure below the practical dose calculation resolution produces deviations in the resulting dose distributions.

The effects of dose calculation resolution on dose accuracy for radiation therapy treatments of the lung. Part I. A Monte Carlo model of the lung.

Purpose: The purpose of this work was to create an anatomically detailed EGSnrc Monte Carlo based model of the right lung. The resulting model, called BRANCH, includes an accurate representation of the right bronchial, arterial, and venous branching networks down to a scale of 0.1 mm.

An enhanced HOWFARLESS option for DOSXYZnrc simulations of slab geometries.

The Monte Carlo code DOSXYZnrc is a valuable instrument for calculating absorbed dose within a three-dimensional Cartesian geometry. DOSXYZnrc includes several variance reduction techniques used to increase the efficiency of the Monte Carlo calculation. One such technique is HOWFARLESS which is used to increase the efficiency of beam commissioning calculations in homogeneous phantoms.

Increasing the speed of DOSXYZnrc Monte Carlo simulations through the introduction of nonvoxelated geometries.

This article presents a method for increasing the speed of DOSXYZnrc Monte Carlo simulations through the introduction of nonvoxelated geometries defined in any coordinate system. Nonvoxelated geometries are used to isolate regions of uniform density and composition from the scoring grid. Particle transport within these geometric regions is not restricted by the boundary constraints of the scoring grid.