Learn More At: Northwest Hospital Gamma Knife Center Dr. Sandra Vermeulen, M.D. Swedish Cancer Institute Northwest Hospital Gamma Knife Center Seattle, Washington

Learn More At: Gamma Knife Centers in the State of Washington Seattle, North Seattle, Downtown Spokane “Tacoma”

Learn More At: Northwest Hospital Founded in 1960 Non-profit community hospital 281 beds

Learn More At: Northwest Gamma Knife Center First Patient treated in the Summer of 1993 Approx total patients treated 3 Radiation Oncologist on site 9 Neurosurgeons

Learn More At: Tumor Institute Radiation Oncology Group Members T. Barnett, J. Blasko, B. Douglas,S. Eulau, P. Grimm, T. Mate, V. Mehta, R. Meier, A. Morris, J. Sylvester, R.Takamyia, A.Tesler, J. Travaglini, S.Vermeulen

Learn More At: Northwest Hospital Gamma Knife Center 50% -50% ownership between 2 hospitals No physician equity ownership 40% of the billing is Global

Learn More At: Gamma Knife Indications Tumor Types 1/3 Malignant 1/3 Functional 1/3 Benign

Learn More At: Consults and Consents All Patients are seen by Neurosurgery and Radiation Oncology before the Gamma Knife Treatment is scheduled All other possible treatment options are explored If the tumor being treated is malignant, the GK procedure is coordinated with patient’s chemotherapy schedule

Learn More At: Gamma Knife Follow-Up Malignant Tumors Patient follow-up is through the department of Radiation Oncology Malignant tumors are followed with an MRI scan every 2 months for 1-2 year

Learn More At: Gamma Knife Follow-Up Benign Tumors and Functional Cases Patient follow-up is through the department of Neurosurgery Benign tumors are scanned with an MRI on an every 6 month bases for 3-5 years AVM are followed angiographically every year until the nidus occludes Functional cases rarely return for a second GK procedure

Learn More At: Gamma Knife Referrals 50% of cases are initially seen by Radiation Oncology

Learn More At: Gamma Knife Frame Placement If multiple metastases are present or the patient has had more than one GK procedure, identifying current targets on the most recent scan will aid in frame placement

Learn More At: Gamma Knife Procedure Pre-scheduled MRI times Conscious sedation Check anticonvulsant levels day before or morning of the procedure Steroids

Learn More At: Gamma Knife “Automatic Positioning System” If there are multiple metastases in vast different locations of the brain, APS will add considerable time to the treatment. As a result, only 1 or 2 cases for that day should be considered.

Learn More At: Northwest Hospital Gamma Knife Center Staffing 3 Nurses 2 Receptions 2 Physicist 1 research assistant

Learn More At: Gamma Knife Clinical Research What is the % of symptomatic necrosis and how does this correlate with volume size? If the tumor is “too” big, can the treatment be staged? What is the lowest effective single fraction dose for treating meningiomas?

Learn More At: Prolonged Corticosteroids use in the Treatment of Brain Metastases with Accelerator Based Radiosurgery compared to Gamma Knife Radiosurgery S Vermeulen, J Rasis, B Mason

Learn More At: Northwest Hospital Gamma Knife Center Brain metastases experience previously published in tumors in 107 patients 91% tumor control < 5% required continuous steroid support

Learn More At: pReference Stereotactic Systems Product of Northwest Medical Physics Treatment delivery Multiple arcs, multi-static fields with custom blocks, multi-leaf collimater field arrangements Frameless Documented < sub millimeter accuracy by an independent report from MD Anderson Cancer Center in 1997

Learn More At: pReference Stereotatic System Between 11/98 and 1/00, 56 brain metastases in 26 patients were treated at the Swedish Cancer Institute

Learn More At: RTOG Tumor Size 2.0 cm (2.4 Gy), cm (18 Gy), cm (15 Gy) Max Dose/Prescription Dose < 2 PITV(volume of prescription isodose /target volume) required to be between 1-2 ACHIEVED IN 44/50 TARGETS OR 88 %

Learn More At: Target Characteristics 50/23 targets/patients were eligible for review Tumor Volume mean 3.9 cc (0.3 – 29.8 cc) Iso mean 89.4% (82-100%) 40/50 or 80% treated with a single fraction

Learn More At: Results Mean survival 9 months (range 2-18 m) 48/50 or 96% Tumor Control 5/50 or 10% complete disappearance of the target on subsequence scans 15/23 patients or 65% required continuous steroid support

Learn More At: Conclusion Possibly less than a 20 % dose gradient within the tumor volume contributes to a limited degree of tumor sterilization and complete response resulting in greater steroid use

Learn More At: Northwest Gamma Knife