A planning with sequential optimization. The dose to

 A 66-year-old gentleman presented to our outpatient department with history of severe left sided facial pain for 7 years, lancinating in type and associated with difficulty in chewing food on the left side. Pain distributed along the maxillary and mandibular components of the nerve. He was diagnosed 7 years back and was started on Tab Carbamezepine 100mg thrice daily, the dose was increased to Tab Carbamazepine 200mg thrice daily. He had no pain relief with medical management. Pain assessment was done using Barrow Neurological Institute pain intensity score- The initial assessment was a score of V (Severe pain or no pain relief) before treatment.A preliminary MRI Brain was done which showed tortuous dilated right vertebral artery coursing in the prepontine cistern, extending to the left Cerebello Pontine angle, abutting and displacing the left trigeminal nerve (cisternal) to the lateral side. Mild altered morphology with flattening of the surface left trigeminal nerve. He was planned for Stereotactic radio surgery Cyber-knife based single fraction treatment using MRI and CT based planning. Planning CT Scan was secured using 1.25mm cuts, planning MRI with 0.6 mm cuts were taken in CISS sequence at the region of interest. Both CT scan and MRI were fused using CDMS (Clinical Data Management System). Contouring was done using both CT and MRI information. Brainstem and the vertebral artery were the organ at risks. Multiplan system version 4.6.1 was used for planning with sequential optimization. The dose to the target was 66Gy in single fraction prescribed at 83% of the isodose line.The treatment was delivered with the Cyber Knife radiosurgery system using a 6MV X band linear accelerator mounted on fully articulated robotic arm. Real time imaging of bony anatomy with two orthogonally positioned x – ray detectors are used to correct intrafraction movement correction.After pre-medications the single fraction was delivered. Fifth day after radiation therapy patient started having pain relief with improvement in chewing food. Tab Carbamazepine was continued with tapering doses and stopped after two months. The Barrow Neurological Institute Pain intensity score after treatment was I (No pain, no medications) at the end of 12 months post treatment. In the above patient pain relief was achieved at the earliest that was within the first week post treatment and post treatment no facial numbness was noted.The image shows CISS sequence of the Brain : Red line shows the course of trigeminal nerve