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Learn More At: www.DoctorVermeulen.com Northwest Hospital Gamma Knife Center Dr. Sandra Vermeulen, M.D. Swedish Cancer Institute Northwest Hospital Gamma.

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Presentation on theme: "Learn More At: www.DoctorVermeulen.com Northwest Hospital Gamma Knife Center Dr. Sandra Vermeulen, M.D. Swedish Cancer Institute Northwest Hospital Gamma."— Presentation transcript:

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

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

3 Learn More At: www.DoctorVermeulen.com Northwest Hospital Founded in 1960 Non-profit community hospital 281 beds

4 Learn More At: www.DoctorVermeulen.com Northwest Gamma Knife Center First Patient treated in the Summer of 1993 Approx. 2500 total patients treated 3 Radiation Oncologist on site 9 Neurosurgeons

5 Learn More At: www.DoctorVermeulen.com 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

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

7 Learn More At: www.DoctorVermeulen.com Gamma Knife Indications Tumor Types 1/3 Malignant 1/3 Functional 1/3 Benign

8 Learn More At: www.DoctorVermeulen.com 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

9 Learn More At: www.DoctorVermeulen.com 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

10 Learn More At: www.DoctorVermeulen.com 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

11 Learn More At: www.DoctorVermeulen.com Gamma Knife Referrals 50% of cases are initially seen by Radiation Oncology

12 Learn More At: www.DoctorVermeulen.com 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

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

14 Learn More At: www.DoctorVermeulen.com 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.

15 Learn More At: www.DoctorVermeulen.com Northwest Hospital Gamma Knife Center Staffing 3 Nurses 2 Receptions 2 Physicist 1 research assistant

16 Learn More At: www.DoctorVermeulen.com 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?

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

18 Learn More At: www.DoctorVermeulen.com Northwest Hospital Gamma Knife Center Brain metastases experience previously published in 1996 288 tumors in 107 patients 91% tumor control < 5% required continuous steroid support

19 Learn More At: www.DoctorVermeulen.com 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

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

21 Learn More At: www.DoctorVermeulen.com RTOG 95-05 Tumor Size 2.0 cm (2.4 Gy), 2.1-3.0 cm (18 Gy), 3.1-4.0 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 %

22 Learn More At: www.DoctorVermeulen.com 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

23 Learn More At: www.DoctorVermeulen.com 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

24 Learn More At: www.DoctorVermeulen.com 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

25 Learn More At: www.DoctorVermeulen.com Northwest Gamma Knife


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