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Doc.Ing. Josef Novotný,CSc
OLF
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Synergy of medicine and technique
RADIOSURGERY Synergy of medicine and technique
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Radiosurgery - Definition
Radiation energy is focused into a small volume of soft tissue. This volume must be well defined regarding localization, size and shape. The energy is delivered in one single session Radiation is delivered by stereotactic procedure Therefore the radiation energy must be delivered selectively to the volume and the radiosurgical procedure must be reproducible.
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Radiosurgery - Definition
High conformity, low selectivity Conformity describes how well the prescription dose is fitted to the target volume Selectivity also takes irradiation to normal tissue into account High conformity, high selectivity
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Radiosurgery - Definition
The delivery of a single, high dose of irradiation to a small and critically located intracranial volume through the intact skull L.Leksell Radiation dose Target volume Smaller Larger Low High Gamma Knife® surgery Stereotactic Radiation Therapy Image Guided Radiation Therapy Intensity Modulated Radiation Therapy Conformal Radiation Therapy Conventional Radiation Therapy
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Heavy charged particles
Stereotactic radiosurgery and radiotherapy Leksell gamma knife Heavy charged particles Stereotactic LINAC Cyber knife Tomotherapy
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Gamma knife radiosurgery flowchart
1. Frame fixation 2. Diagnostic imaging 3. Treatment planning 4. Treatment
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How does it work? Stereotactic target localization
Frame fixation Imaging Head measurements
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Stereotactic localization
MR indicator box CT indicator box DSA indicator box
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Stereotactic target localization
Image definition Space definition Axial Images Coronal images . . . . . .
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Radiosurgery – Imaging
Leksell coordinate frame provides optimal stereotactic localization Supports all imaging modalities (CT, MRI, PET and Angio) Digital image transfer to Leksell GammaPlan
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Treatment Planning Leksell GammaPlan® PFX™
We want Maximum dose to the target Minimum dose to the surrounding healthy tissue Optimized dose distribution We can use Multiple beams Different weighting (time) Multiple iso-centers Different collimators Plugs
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Treatment Planning Leksell GammaPlan® PFX™
A] Patient data - personnel data - head data B] Beam data – dose distribution - PDD - linear attenuation coefficient - dose rate - output factors C] Images – MR, CT, PET, angiography D] Calculation algorithm
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Treatment planning 14 mm 8 mm 8 mm 4 mm 8 mm 4 mm 8 mm 14 mm
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Treatment planning TV = Tumor Volume
Conformity of the prescribed dose to the target volume = PIV/TV = 6.3/5.2 = 1.2 PIV = Prescription Isodose Volume
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Treatment Planning Leksell GammaPlan® PFX™ * Dose performance
Collimator design provides almost unlimited ability for sculpturing the dose distribution * Shot features enabled Classic (combination of 4, 8, 16 mm shots) Composite (any combination of B, 4, 8, 16 mm sectors) Dynamic shaping Collimator system * PC based treatment planning system with client-server architecture
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Unlimited intracranial treatment reach
Leksell GammaPlan® PFX™
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Arterio-venous malformation
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Medieval “radiosurgery and radiotherapy”
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Pioneering radiosurgery 1951 - 1968
The first prototype of the Leksell Gamma Knife was installed in 1968 at Sophiahemmet Hospital in Stockholm, Sweden. 20
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Gamma Knife model U UPMC GAMMA KNIFE MODEL U • Installed in • 201 sources with 4, 8, 14 and 18 mm collimators • Manual setting of coordinates
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Leksell Gamma Knife - principles
Model B, C, 4C Protective shielding Spherical collimator helmet Leksell Stereotactic System® Isocenter/ Target in the brain Automatic Positioning System™ Radiation source Co-60
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Gamma Knife model B Manual setting of coordinates Trunnion fixation
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Leksell gamma knife model C and 4C Automatic Positioning System (APS)
Z X 24
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Gamma Knife model 4C Last treatment on 12.11.2009
No of treated patients Upgraded in • 201 sources with 4, 8, 14 and 18 mm collimators • Automatic Positioning System [APS] * More safety features
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Development of the PERFEXION
In 2002 formed a group within Leksell Gamma Knife Society consisting of neurosurgeons, radiation oncologists and medical physicists. ELEKTA asked this group the simple yet complex question: What is the ultimate tool for Gamma Knife surgery? 26
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Identified Seven Critical Features for the new system
Best dosimetry performance (accuracy, precision, reliability) Best radiation protection for patients and staff Unlimited cranial reach Full automatization (with the maximum of commercial parts) Outstanding patient and staff comfort Keeping the unique robustness of the Gamma Knife Consistency with previous Gamma Knife systems
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Leksell Gamma Knife PERFEXION
Introduced in 2006 New collimator design New safety doors and shielding Patient positioning system 28
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Patient Positioning System (PPS)
Leksell gamma knife model PERFEXION Patient Positioning System (PPS) PPS Y Z X 29
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Advantages of the Patient Positioning System
Very easy and fast to operate no positioning checks needed Time efficient for the patient treatment all targets can be treated mostly in a single run High patient comfort whole patient’s body moves in a treatment position 30
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LGK PERFEXION radiation unit and collimator
sector design
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Collimator System for LGK PERFEXION
4, 8, 16 mm collimators No collimator helmets 192 Co-60 sources Cylindrical source geometry
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Leksell Gamma Knife - principles
Knife C Leksell Gamma Knife PERFEXION - Increased treatable volume by more than 300% - Cerebral cases ~ 10% increase in available number of patients for existing indications due to extended reachability - Head & neck ~ 10 % additional patients from lesions in paranasal sinuses, orbits and some upper cervical lesions - Cervical lesions ~ 20% additional with upcoming fixation technique
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Calibration Procedure
Calibration of source positions, i.e. calibrating the sector positions Calibrating the movements of the Patient Positioning System. Calibrating the Patient Positioning System vs. the Radiological Focus
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Service Diode Test Tool
1 3 2 1- Central Diode X=100, Y=100, Z=100 2 - Short Diode X=100, Y=50, Z=115 3 - Long Diode X=160, Y=100, Z=22
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Focus Pin Prick Film Test
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How does weight effect results?
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Results – PPS QA with Service Diode Test Tool
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Physical and technical accuracy
Leksell gamma knife Isocenter accuracy: 0.5 mm Stereotactic target localization accuracy: 0.8 mm Stereotactic target irradiation accuracy: 0.2 mm Overall accuracy: mm = 1.0 mm
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Time scale of radiation effects
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AVM Acoustic neuroma Clinical applications Meningioma
Vascular diseases AVM AOVM Other vascular Benign tumors treatment 3 years Acoustic neuroma Meningioma Pituitary adenoma Other benign tumors 5 years 10 years
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Metastasis Clinical applications Malignant tumors Glial tumors
Other malignant tumors Treatment 6 years
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Before GK 39 months after GK F 3 y. Before radiosurgery glioblastoma
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Clinical applications
Functional disorders Trigeminal neuralgia Intractable pain Parkinson’s disease Epilepsy Other functional disorders Trigeminal neuralgia Ophthalmologic indications Uveal melanoma Other ophthalmologic indications Uveal melanoma
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Clinical applications
Glaucoma Four 8 mm isocenters
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Clinical applications
No of treated patients Rok
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Clinical applications
Hospital Na Homolce Total No 4039 patients Oční AVM Funkční Benigní Maligní
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DĚKUJI ZA POZORNOST
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