Optimizing CyberKnife Stereotactic Radiosurgery for Motor-eloquent Brain Arteriovenous Malformations Using Diffusion...

Area of Science:

• Neurosurgery
• Radiation Oncology
• Medical Imaging

Background:

• Stereotactic radiosurgery (SRS) for brain arteriovenous malformations (bAVMs) near motor areas is challenging due to potential radiation damage to sensitive white matter (WM).
• Preserving motor function requires careful management of radiation exposure to adjacent WM tracts.

Purpose of the Study:

• To evaluate the use of diffusion tensor imaging (DTI)-based magnetic resonance (MR) tractography in planning CyberKnife SRS for bAVMs.
• To minimize radiation dose to motor-relevant WM tracts and reduce the risk of post-treatment motor deficits.

Main Methods:

• DTI-based WM tract reconstructions from 22 patients were integrated into the CyberKnife planning system.
• WM tracts were delineated as dose constraint volumes to spare them from radiation.
• Treatment plans with and without WM tract constraints were compared to assess dose reduction.

Main Results:

• WM tract constraints reduced the maximum radiation dose by an average of 17.68% (from 20.81 Gy to 17.13 Gy).
• Significant dose reductions were observed across various dose levels (V50%, V40%, V30%, V20%) for WM tracts (P < 0.01).
• Planning target volume coverage remained unaffected, and all other dose constraints were met.

Conclusions:

• Integrating DTI-based MR tractography into CyberKnife SRS planning for motor-eloquent bAVMs is feasible.
• This technique effectively preserves critical motor tracts.
• The approach minimizes radiation risk to WM without compromising treatment efficacy.