Delivery of intensity-modulated electron therapy by mechanical scanning: An algorithm study.

Area of Science:

• Medical Physics
• Radiation Oncology
• Robotics in Medicine

Background:

• Intensity-modulated electron therapy (IMET) offers precise radiation delivery.
• Mechanical scanning with a robotic arm presents a potential method for IMET delivery.

Purpose of the Study:

• To develop and evaluate a scanning algorithm for intensity-modulated electron therapy (IMET) using mechanical scanning.
• To optimize the delivery sequence for IMET to minimize treatment time.

Main Methods:

• A zigzag scanning algorithm was developed, generating beam positions and selecting discrete energies for target depth.
• Fast simulated annealing (FSA) was employed to optimize the delivery order of scan spots, minimizing path length.
• The algorithm was evaluated using CT data from 10 pancreatic cancer patients undergoing intraoperative radiotherapy.

Main Results:

• FSA optimization reduced scan path lengths by 12%-43% in clinical cases.
• The average treatment delivery time was 124±38 seconds, with path length reduction yielding up to a 10% decrease.
• Further reductions in delivery time are possible by increasing machine dose rate, robotic arm speed, and optimizing algorithms.

Conclusions:

• Mechanically scanned IMET is a feasible and promising approach for radiation therapy.
• The developed scanning algorithm and optimization strategy effectively reduce treatment delivery time.
• Further research and development in this area warrant exploration for clinical application.