1. Neurosurgery Department Shuang Ho Hospital New Taipei City, Taiwan Wei-Lun Lo, M.D. THE APPLICATION OF PERFEXION GAMMA KNIFE RADIOSURGERY FOR INFRA-SKULL BASE LESIONS

2. TECHNICAL LIMIT OF GKS Traditional lower limit of treatment related to lesion locations: Foramen mangnum Kondziolka et al: Radiosurgery of meningiomas. Neurosurg Clin N Am 3:219–230, 1992 However, the data from new Perfexion version was not included. J Craniovertebr Junction Spine. 2010 Jan-Jun; 1(1): 23-28

3. Primary lesion at neck Extracranial ↑↓ Intracranial POSTING DIFFICULTY FOR GKS

4. COMPARISON OF GK SYSTEMS

5. CASE DISTRIBUTION (N = 14)

6. Paraganglioma 39 y/o female horseness and dysphonia; paraganglioma from posterior fossa with extension to neck region s/p partial resection by ENT doctor 2013/10/15 TV: 18.3 2014/4/22 TV: 7 Volume: 18.3c.c. RV: 23.5c.c. PD: 12.5 Gy MD: 22.3 Gy ID: 56% Mean dose: 16.7 Gy

7. Foramen Mangnum Meningioma 37 year-old female Meningiomatosis in petroclival, foramen magnum, and ventral C5 regions s/p surgical excision of C5 meningioma 2013/8/23 TV: 1.2 2014/2/24 TV: 1.2 Volume: 1.2 c.c. RV: 3.3 c.c. PD: 12 Gy MD: 21.8 Gy ID: 55% Mean dose: 16.6 Gy

8. Skull Base Metastasis 74 year-old female Hx of breast cancer s/p operation; facial numbness, difficult swallowing, tongue atrophy 2013/7/11 TV: 27.2 2014/7/24 TV: 3.5 Marked regression Improvement of tongue atrophy & swallowing function Volume: 27.2 c.c. RV: 35.2 c.c. PD: 12.8 Gy MD: 24.6 Gy ID: 52% Mean dose: 17.5 Gy

9. PRELIMINARY RESULT Tumor Tumor shrinkage, stationary, or loss of central enhancement in all cases Vascular lesion No interval hemorrhage in follow up period

10. MOTION ERROR J Neurosurg (Suppl) 117: 211-216, 2012 Cervical Immobilization !!

11. GKS FOR EXTRACRANIAL LESION: CAROTID BODY TUMOR C2 C3

12. PRE-TREATMENT MANAGEMENT Cervical immobilizationFeasibility evaluation

13. TV: 3.2 c.c. Radiation volume: 4.8 c.c. Peripheral dose: 15.5 Gy Maximum dose: 28.2 Gy Isodose level at periphery: 55% Mean dose: 22.4 Gy

14. THANKS FOR ATTENTION