A generalized inverse planning tool for volumetric-modulated arc therapy

Area of Science:

• Medical Physics
• Radiation Oncology
• Radiotherapy Technology

Background:

• Volumetric-modulated arc therapy (VMAT) is an advanced form of intensity-modulated radiation therapy (IMRT).
• VMAT involves simultaneous adjustments in dose rate, gantry angle, gantry rotation speed, and multi-leaf collimator (MLC) positions during radiation delivery.
• New linear accelerator control systems enable sophisticated VMAT techniques.

Purpose of the Study:

• To describe a generalized VMAT planning tool designed for advanced linear accelerator control systems.
• To incorporate MLC delivery constraints, including leaf interdigitation restrictions and velocity constraints.
• To enable planning for both single- and multiple-arc VMAT deliveries.

Main Methods:

• Development of a generalized VMAT planning algorithm.
• Integration of MLC delivery constraints into the planning algorithm.
• Capability for planning single- and multiple-arc VMAT deliveries.

Main Results:

• VMAT plans generated using the tool demonstrated similar or superior plan quality compared to conventional step-and-shoot IMRT.
• Plans achieved reduced monitor units (MU) and improved delivery efficiency.
• Plan verification on an Elekta Synergy linear accelerator confirmed the accuracy of the VMAT plans.

Conclusions:

• The developed VMAT planning tool effectively utilizes advanced linac control system capabilities.
• The tool facilitates the creation of efficient and accurate VMAT plans.
• VMAT planning offers advantages over conventional IMRT in terms of plan quality, MU, and delivery efficiency.