Effects of respiratory motion on dose uniformity with a charged particle scanning method

TLDR

A three‑dimensional spot‑scanning proton radiotherapy technique is under development. The study aimed to optimize design and achieve clinically useful dose distributions by simulating dose deposition under respiratory motion. A computer program modeled dose in a uniform water volume while systematically varying respiration amplitude, period, direction, fraction number, beam‑spot size/position, and rescanning multiplicity to assess their impact. Initial experiments characterized the proton beam and scanning procedure.

Abstract

A three-dimensional spot-scanning technique for radiotherapy with protons is being developed. As part of the effort to optimize the design and ensure clinically useful dose distributions, a computer simulation of the dose deposition in the presence of respiratory motion was performed. Preliminary experiments have characterized the proton beam and the scanning procedure. Using these parameters, the computer program calculated the dose within a uniform volume of water in the presence of respiratory motion. Respiration amplitude, respiration period, respiration direction, number of fractions, size and position of the beamspots and rescanning multiplicity were systematically varied and the effect on the dose distribution determined.