Dose-volume histogram quality assurance for linac-based treatment planning systems

Area of Science:

• Medical Physics
• Radiation Oncology
• Radiotherapy Quality Assurance

Background:

• Dose-volume histograms (DVHs) are crucial for assessing radiation therapy treatment plan adequacy.
• Ensuring the accuracy of DVH data is paramount for effective patient treatment.
• Current quality assurance (QA) methods for treatment planning systems (TPS) require robust verification.

Purpose of the Study:

• To introduce a novel QA routine for radiation therapy treatment planning systems.
• To validate the accuracy of volumetric statistics generated by TPS.
• To establish a direct comparison method between TPS calculations and independent hand calculations.

Main Methods:

• Developed a time-efficient and reproducible QA method for TPS.
• Utilized a known 3-D structure, simple beam arrangement, and known physics beam data.
• Performed direct comparison of TPS-generated DVH data with independent hand calculations.

Main Results:

• Maximum disagreement in DVH data was 1.7% for 6 MV and 1.3% for 18 MV photon energies.
• Average accuracy for depth-dose results was within 0.6% for 6 MV and 0.4% for 18 MV.
• Observed a 2% disagreement in DVH from defined volume comparison to known structure dimensions.

Conclusions:

• The presented QA method provides rapid and reliable verification of TPS accuracy.
• This routine satisfies QA requirements for TPS commissioning, upgrades, and annual checks.
• The method ensures the clinical relevance and accuracy of DVH data in radiation therapy planning.