Multi-isocenter VMAT craniospinal irradiation using feasibility dose-volume histogram-guided auto-planning technique

Area of Science:

• Radiation Oncology
• Medical Physics
• Cancer Treatment

Background:

• Craniospinal irradiation (CSI) is a complex radiotherapy technique.
• Volumetric modulated arc therapy (VMAT) offers potential advantages for CSI.
• Optimizing VMAT for CSI, especially with multiple isocenters, presents planning challenges.

Purpose of the Study:

• To propose and evaluate a novel treatment planning methodology for multi-isocenter VMAT-CSI.
• To utilize a feasibility dose-volume histogram (FDVH)-guided auto-planning (AP) technique.
• To compare the proposed FDVH-guided AP plans (FAPs) against manually based plans (MUPs) and conventional AP plans (CAPs).

Main Methods:

• Three types of multi-isocenter VMAT-CSI plans were generated: MUPs, CAPs, and FAPs.
• CAPs and FAPs were created using the Pinnacle treatment planning system, integrating multi-isocenter VMAT and AP.
• FAPs employed personalized optimization parameters derived from the FDVH function in PlanIQ software for OARs sparing.

Main Results:

• Both CAPs and FAPs significantly reduced doses to most organs at risk (OARs) compared to MUPs.
• FAPs demonstrated superior plan quality with the best homogeneity and conformity indices.
• FAPs achieved comparable or slightly better OAR sparing than CAPs, with significantly reduced planning time compared to MUPs.

Conclusions:

• The multi-isocenter AP technique, particularly FDVH-guided AP, shows promise for VMAT-CSI.
• This novel methodology enhances OARs sparing and reduces planning time.
• FDVH-guided AP represents a valuable advancement for clinical CSI planning.