Related Experiment Video
Updated: Feb 16, 2026
10:35
Stereotactic Radiosurgery for Gynecologic Cancer
Published on: April 17, 2012
18.8K
Dosimetric characterization of Elekta stereotactic cones
Egor Borzov1, Alexander Nevelsky1, Raquel Bar-Deroma1
1Department of Radiotherapy, Division of Oncology, Rambam Health Care Campus, Haifa, Israel.
Journal of Applied Clinical Medical Physics
|December 22, 2017
Summary
Accurate Monte Carlo (MC) simulations validate dosimetry for stereotactic cones, crucial for small field radiation therapy. Variations in cone size significantly impact output factors, highlighting the need for precise manufacturing.
Area of Science:
- Medical Physics
- Radiation Oncology
- Radiotherapy Dosimetry
Background:
- Small field dosimetry presents challenges in stereotactic radiosurgery.
- Accurate dose delivery is critical for effective cancer treatment with minimal side effects.
Purpose of the Study:
- To commission and validate a new Elekta stereotactic cone system for a VersaHD linac.
- To compare measured dosimetry data with Monte Carlo (MC) simulations for a 6 MV FFF beam.
- To assess the impact of cone aperture variations on relative output factors (ROF) and penumbra characteristics.
Main Methods:
- Measurements of percentage depth dose (PDD), off-axis ratios (OAR), and ROF using a stereotactic field diode (SFD).
- BEAMnrc code employed for MC simulations of the stereotactic cone system.
- Comparison of measured data against MC-calculated data for various cone sizes (5-15 mm).
Main Results:
- Excellent agreement between measured and MC-simulated PDDs (within 1%/0.5 mm) and OARs (within 1%/0.5 mm).
- ROF agreement between measurements and MC calculations was within 2% for all cone sizes.
- Small variations in cone aperture (±0.3 mm) caused significant ROF changes (2-10%), and cone-based fields showed sharper penumbra than MLC-based fields.
Conclusions:
- MC simulations are a reliable tool for verifying small field dosimetry measurements.
- Manufacturing tolerances in stereotactic cone diameter critically influence dosimetric accuracy.
- Precise quality assurance is essential for stereotactic cone-based radiotherapy treatments.
