250 likes | 682 Views
Northwest Hospital Gamma Knife Center Dr. Sandra Vermeulen, M.D. Swedish Cancer Institute Northwest Hospital Gamma Knife Center Seattle, Washington. Seattle, North Seattle, Downtown Spokane “Tacoma”. Gamma Knife Centers in the State of Washington. Founded in 1960
E N D
Northwest Hospital Gamma Knife Center Dr. Sandra Vermeulen, M.D. Swedish Cancer Institute Northwest Hospital Gamma Knife Center Seattle, Washington
Seattle, North Seattle, Downtown Spokane “Tacoma” Gamma Knife Centers in the State of Washington
Founded in 1960 Non-profit community hospital 281 beds Northwest Hospital
First Patient treated in the Summer of 1993 Approx. 2500 total patients treated 3 Radiation Oncologist on site 9 Neurosurgeons Northwest Gamma Knife Center
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 Tumor Institute Radiation Oncology Group
50% -50% ownership between 2 hospitals No physician equity ownership 40% of the billing is Global Northwest Hospital Gamma Knife Center
1/3 Malignant 1/3 Functional 1/3 Benign Gamma Knife IndicationsTumor Types
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 Consults and Consents
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 Gamma Knife Follow-UpMalignant Tumors
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 Gamma Knife Follow-UpBenign Tumors and Functional Cases
50% of cases are initially seen by Radiation Oncology Gamma Knife Referrals
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 Gamma Knife Frame Placement
Pre-scheduled MRI times Conscious sedation Check anticonvulsant levels day before or morning of the procedure Steroids Gamma Knife Procedure
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. Gamma Knife“Automatic Positioning System”
3 Nurses 2 Receptions 2 Physicist 1 research assistant Northwest Hospital Gamma Knife Center Staffing
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? Gamma KnifeClinical Research
S Vermeulen, J Rasis, B Mason Prolonged Corticosteroids use in the Treatment of Brain Metastases with Accelerator Based Radiosurgery compared to Gamma Knife Radiosurgery
Brain metastases experience previously published in 1996 288 tumors in 107 patients 91% tumor control < 5% required continuous steroid support Northwest Hospital Gamma Knife Center
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 pReference Stereotactic Systems
Between 11/98 and 1/00, 56 brain metastases in 26 patients were treated at the Swedish Cancer Institute pReference Stereotatic System
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 % RTOG 95-05
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 Target Characteristics
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 Results
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 Conclusion