3482 - Neuroanatomical Synergy in Cyberknife Stereotactic Ablative Neuromodulation: Revisiting Contouring Paradigms with Dopamine PET-CT and Fgatir MRI for Ventral Intermediate Nucleus Targeting in Parkinson's Disease for Improved Outcomes — A Subcontinental Fir
Presenter(s)
G. Lohith1, K. Sekar2, S. S. Shivalingappa3, K. Kallur3, A. K. BS3, A. Pichandi4, and H. G. ramesh Gowda5; 1Immuno-Rad Lab , HCG Hospitals, BANGALORE, India, 2HCG Hospitals, Bengaluru, karnataka, India, 3Health Care Global Enterprises Ltd, Bangalore, India, 4HCG Hospital, Banglore, India, 5HCG Hospitals, Bengaluru, Karnataka, India
Purpose/Objective(s): A frameless robotic radiosurgery system is a non-invasive approach for alleviating motor symptoms in Parkinson’s disease (PD) by targeting dysfunctional neural circuits, such as the ventral intermediate nucleus(ViM), subthalamic nucleus or globus pallidus. This system delivers highly focused radiation for precise neuromodulation. Advanced imaging, including dopamine PET-CT and fast gray matter T1-weighted MRI, enhances treatment precision. Dopamine PET-CT maps dopamine deficiency, a hallmark of PD, while fast gray matter T1 MRI improves structural visualization for accurate ViM localization. Fusing these modalities ensures precise targeting while minimal damage to healthy tissue and improving outcomes
Materials/Methods: 9 Indian patients with tremor-predominant PD underwent CR ViM targeting using dopamine PET-CT and FGATIR MRI. The mid-commissural line served as reference, with target 12 mm lateral to this line. A 3 mm volume was contoured above the target across three MRI slices for lesioning precision.
The ViM’s horizontal extent ranged from 9 to 11 mm, necessitating individualized adjustments. Instead of relying solely on fixed measurements, we used internal capsule as lateral endpoint, verified with FGATIR MRI. Dopamine PET-CT also aided in lateralizing the side of dopaminergic deficiency, enhancing targeting accuracy. CR provided frameless, stereotactic Vim ablation using 85Gray single fraction keeping internal capsule max dose < 35 Gray for optimal tremor control.Results: 90% of patients experienced more than 80% tremor relief, while remaining 10% saw over 50% improvement. The multimodal imaging approach significantly enhanced Vim localization, optimizing stereotactic interventions. Internal capsule-based lateral boundary assessment improved tremor control outcomes, reducing inaccuracies seen with conventional techniques. A frameless robotic radiosurgery system proved to be non-invasive, effective alternative to traditional interventions, achieving durable tremor suppression. Statistical analysis confirms that a frameless robotic radiosurgery system significantly improves tremor severity, validating its efficacy for treating tremor-predominant Parkinson’s disease.
Conclusion: Integrating PET-CT and FGATIR MRI enables precise ViM localization, particularly in Indian patients with anatomical variations. Using the internal capsule as a lateral boundary improves stereotactic accuracy, minimizing reliance on predefined measurements. Dopamine PET-CT further aids in lateralizing dopaminergic deficiency, supporting patient selection and intervention planning. A frameless robotic radiosurgery system offers a precise and effective non-invasive treatment option, reducing risks associated with invasive procedures
| Statistic | Value |
|---|---|
| Sample Size (n) | 9 |
| Mean Pre-Treatment Grade | 3.89 |
| Mean Post-Treatment Grade | 1.11 |
| Mean Difference (Pre - Post) | 2.78 |
| Standard Deviation of Differences | 0.83 |
| t-Statistic | 10.00 |
| p-Value | 8.49 × 10?6 |