Surface guided imaging during stereotactic radiosurgery with automated delivery

Area of Science:

• Medical Physics
• Radiation Oncology
• Image Guidance

Background:

• Frameless intracranial stereotactic radiotherapy requires precise patient immobilization.
• Monitoring intrafraction motion is crucial for treatment accuracy.
• Automated delivery systems like HyperArc aim to streamline radiotherapy delivery.

Purpose of the Study:

• To evaluate the efficacy of surface-guided imaging (SI) for monitoring intrafraction motion.
• To assess the performance of the AlignRT® system during frameless intracranial stereotactic radiotherapy with HyperArc™ automated delivery.
• To investigate potential influences of patient demographics and treatment parameters on motion monitoring accuracy.

Main Methods:

• Utilized the AlignRT® surface imaging system to monitor intrafraction motion in patients undergoing HyperArc™ radiotherapy.
• Correlated AlignRT® log files with treatment trajectory logs to analyze motion offsets.
• Investigated performance at non-zero couch angles and during camera-pod blockage.
• Analyzed motion data stratified by patient race to assess potential skin tone-related differences.

Main Results:

• Median reported motion from treatment start to end was 0.24 mm.
• Median offset before beam delivery at non-zero couch angles was 0.55 mm.
• Median motion magnitude during gantry motion with camera-pod blockage was below 1 mm.
• No significant differences in motion offsets were observed for patients stratified by race.

Conclusions:

• Surface image guidance is a practical and effective method for monitoring intrafraction motion.
• SI provides a viable alternative to scheduled mid-treatment imaging during automated stereotactic radiosurgery.
• The AlignRT® system demonstrates reliable performance in conjunction with HyperArc™ for frameless intracranial radiotherapy.