Accuracy of tumor motion compensation algorithm from a robotic respiratory tracking system: a simulation study.

Area of Science:

• Medical Physics
• Radiation Oncology
• Robotic Surgery

Background:

• Tumor motion due to respiration complicates radiation therapy.
• Traditional methods like gated therapy can reduce linac efficiency.
• The Synchrony Respiratory Tracking System (RTS) offers a solution for real-time tumor tracking.

Purpose of the Study:

• To evaluate the effectiveness of the RTS in reducing treatment errors caused by respiratory motion.
• To investigate the impact of different correspondence models and update frequencies on tracking accuracy.
• To assess RTS performance using computer simulations based on real patient data.

Main Methods:

• Computer simulations using continuous internal tumor and external marker motion data from eight lung cancer patients.
• Modeling the relationship between internal and external markers using linear and polynomial models.
• Simulating the RTS's lower x-ray imaging frequency (once per minute) to assess tracking accuracy.

Main Results:

• The RTS significantly reduced simulated treatment errors due to breathing motion across all patients.
• A linear correspondence model achieved substantial error reduction.
• Polynomial models offered additional benefits in cases of hysteresis.
• More frequent model updates yielded minor improvements only for rapidly changing motion patterns.

Conclusions:

• The RTS, utilizing both internal and external markers, enables accurate tumor motion tracking.
• The system demonstrates effectiveness even with irregular breathing patterns.
• The RTS provides a viable option for reducing treatment errors in respiratory-gated radiation therapy.