Back
Effects of respiratory motion on dose uniformity with a charged particle scanning method.
Journal article

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

Show more…
  • 1992-01-01
Published in:
  • Physics in medicine and biology. - 1992
Computer Simulation
Humans
Movement
Protons
Radiotherapy Dosage
Radiotherapy, High-Energy
Respiration
English A three-dimensional spot-scanning technique for radiotherapy with protons is being developed at the Paul Scherrer Institute. 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. The dose uniformity is very dependent on the direction of the respiration relative to the three independent beam scanning directions. The dose uniformity decreases with increasing respiration amplitude, but has little response to changes in respiration frequency. Rescanning the volume, such as with fractionation, improves the dose uniformity roughly as the square root of the number of fractions. Broad, Gaussian beams result in better dose uniformity than narrow, sharply delineated ones, but produce slower dose fall-off at the edges of the scanned volume. Results of this work are being incorporated into the design of the system.
Language
  • English
Open access status
closed
Identifiers
Persistent URL
https://sonar.ch/global/documents/668
Statistics
Document views: 22 File downloads: