Anatomically robust proton therapy using multiple planning computed tomography scans for locally advanced prostate...

Area of Science:

• Radiation Oncology
• Medical Physics
• Prostate Cancer Treatment

Background:

• Proton therapy (PT) is susceptible to anatomical variations during treatment.
• Pelvic irradiation for locally advanced prostate cancer necessitates robust treatment planning.

Purpose of the Study:

• To evaluate if anatomically robust proton therapy (ARPT) plans improve target coverage and spare normal tissues in prostate cancer patients.
• To compare ARPT with conventional robust PT and VMAT photon plans.

Main Methods:

• ARPT plans were created using patient-specific targets from multiple CT scans.
• Plans were compared against conventional robust PT and VMAT plans.
• Robust optimization with 5mm setup and 3.5% range uncertainty was used.
• Target coverage (V95%, D95%) and normal tissue doses (V5-75Gy) were assessed.

Main Results:

• ARPT significantly improved prostate target coverage for the most challenging patient.
• Mean V95% was 97% for ARPT vs. 95% for conventional robust PT.
• ARPT showed a slight, non-significant increase in normal tissue doses compared to conventional PT.
• ARPT plans significantly reduced low-to-intermediate dose normal tissue exposure compared to VMAT.

Conclusions:

• ARPT enhances target coverage in challenging cases without substantially increasing normal tissue dose compared to conventional PT.
• Both PT techniques reduced low-to-intermediate dose normal tissue exposure versus VMAT.