Dose volume histogram comparison between ADAC Pinnacle and Nomos Corvus systems for IMRT.

Area of Science:

• Radiation Oncology
• Medical Physics
• Radiotherapy Planning

Background:

• Accurate dose calculation is crucial in radiotherapy.
• Different treatment planning systems (TPS) employ varied algorithms, potentially leading to discrepancies.
• Understanding these differences is vital for consistent clinical outcomes.

Purpose of the Study:

• To compare dose volume histograms (DVHs) generated by ADAC Pinnacle and Nomos Corvus planning systems.
• To evaluate the impact of different dose calculation algorithms on DVH parameters.
• To assess the clinical significance of observed discrepancies.

Main Methods:

• Comparison of DVHs from seven prostate and seven head and neck cancer cases.
• Utilized identical anatomical contours and intensity-modulated radiation therapy (IMRT) segments for both systems.
• Pinnacle used collapsed cone convolution superposition; Corvus used finite size pencil beam (FSPB) convolution.

Main Results:

• Prostate DVH curves showed similarities between systems.
• Ratios of Pinnacle to Corvus dose values were near unity for high-dose structures (tumors) and further from unity for low-dose structures (critical organs).
• A systematic difference was observed, with Pinnacle doses generally lower than Corvus, potentially due to beam modeling variations.

Conclusions:

• The study identified systematic differences in DVH calculations between Pinnacle and Corvus TPS.
• These differences, particularly in low-dose regions for critical organs, are comparable to measurement-computation uncertainties.
• The observed discrepancies may influence clinical planning decisions when precise low-dose management is critical.