Frame-less and mask-less cranial stereotactic radiosurgery: a feasibility study

Area of Science:

• Medical Physics
• Radiotherapy Technology
• Image-Guided Therapy

Background:

• Stereotactic radiosurgery (SRS) demands high precision, typically achieved through rigid immobilization.
• Rigid immobilization causes patient discomfort, potentially leading to movement during lengthy SRS procedures.
• A novel SRS approach is proposed to enhance patient comfort while maintaining treatment accuracy.

Purpose of the Study:

• To evaluate the feasibility of a new SRS technique.
• To assess a less-rigid immobilization method combined with real-time motion monitoring.
• To ensure high-precision treatment delivery with improved patient comfort.

Main Methods:

• An anthropomorphic head phantom was used to validate a 3D surface imaging system for motion monitoring.
• Volunteers were enrolled to assess head motion within a novel, minimally immobilizing head mold.
• Accuracy was verified by comparing surface imaging system data with an infrared optical tracking system.

Main Results:

• The surface imaging system demonstrated accuracy within 1 mm and 1 degree compared to optical tracking for phantom positioning.
• Volunteer head motion in the head mold averaged 0.7 mm over 20 minutes, with patient motion due to couch shifts under 0.2 mm.
• Real-time surface imaging accurately detected minimal head motion within the head mold.

Conclusions:

• The developed SRS technique is feasible for minimizing patient discomfort.
• Less-rigid immobilization combined with real-time motion monitoring maintains high-precision SRS delivery.
• Continuous surface imaging effectively monitors small head movements in minimally immobilized patients.