Validation of a quick three-dimensional dose verification system for pre-treatment IMRT QA

Area of Science:

• Medical Physics
• Radiation Oncology
• Dosimetry

Background:

• Accurate three-dimensional (3D) dose verification is crucial for intensity-modulated radiation therapy (IMRT).
• Traditional quality assurance (QA) methods can be time-consuming.
• Advanced systems are needed to improve efficiency and reliability in IMRT QA.

Purpose of the Study:

• To evaluate the dosimetric performance of the COMPASS version 3 (three-dimensional dose verification system).
• To compare the COMPASS system with EDR2 films and Monte Carlo (MC) simulations for dose verification.
• To assess the efficiency of the COMPASS system in clinical IMRT QA workflows.

Main Methods:

• The COMPASS system's dose profiles were measured using multi-leaf collimator (MLC) test patterns.
• Comparisons were made against EDR2 films and MC simulations.
• The system was used for dose verification in clinical head and neck IMRT plans, with comparisons to 3DVH and MC.
• Quality assurance (QA) times were compared across COMPASS, 3DVH, and EDR2 film.

Main Results:

• COMPASS dose profiles agreed within 3% with EDR2 films and MC simulations for MLC test patterns.
• Dose resolution for MLC patterns was comparable to film, despite lower physical resolution.
• Dose-volume-histograms for clinical plans were consistent across all evaluated systems.
• Average QA times: COMPASS (40.1 min), 3DVH (59.4 min), EDR2 film (121.4 min).

Conclusions:

• The COMPASS system provides fast and reliable 3D dose verification for clinical IMRT QA.
• Its ability to reconstruct dose distributions on patient CT images simplifies the QA workflow.
• The COMPASS system eliminates the need for phantom plans, streamlining the QA process.