Doc.Ing. Josef Novotný,CSc OLF

Synergy of medicine and technique RADIOSURGERY Synergy of medicine and technique

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.

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

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

Heavy charged particles Stereotactic radiosurgery and radiotherapy Leksell gamma knife Heavy charged particles Stereotactic LINAC Cyber knife Tomotherapy

Gamma knife radiosurgery flowchart 1. Frame fixation 2. Diagnostic imaging 3. Treatment planning 4. Treatment

How does it work? Stereotactic target localization Frame fixation Imaging Head measurements

Stereotactic localization MR indicator box CT indicator box DSA indicator box

Stereotactic target localization Image definition Space definition Axial Images Coronal images . . . . . .

Radiosurgery – Imaging Leksell coordinate frame provides optimal stereotactic localization Supports all imaging modalities (CT, MRI, PET and Angio) Digital image transfer to Leksell GammaPlan

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

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

Treatment planning 14 mm 8 mm 8 mm 4 mm 8 mm 4 mm 8 mm 14 mm

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

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 8-16-8-16-8-16-8-16 * PC based treatment planning system with client-server architecture

Unlimited intracranial treatment reach Leksell GammaPlan® PFX™

Arterio-venous malformation

Medieval “radiosurgery and radiotherapy”

Pioneering radiosurgery 1951 - 1968 The first prototype of the Leksell Gamma Knife was installed in 1968 at Sophiahemmet Hospital in Stockholm, Sweden. 20

Gamma Knife model U UPMC GAMMA KNIFE MODEL U • Installed in 1987 • 201 sources with 4, 8, 14 and 18 mm collimators • Manual setting of coordinates

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

Gamma Knife model B Manual setting of coordinates Trunnion fixation

Leksell gamma knife model C and 4C Automatic Positioning System (APS) Z X 24

Gamma Knife model 4C Last treatment on 12.11.2009 No of treated patients 10 525 Upgraded in 2006 • 201 sources with 4, 8, 14 and 18 mm collimators • Automatic Positioning System [APS] * More safety features

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

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

Leksell Gamma Knife PERFEXION Introduced in 2006 New collimator design New safety doors and shielding Patient positioning system 28

Patient Positioning System (PPS) Leksell gamma knife model PERFEXION Patient Positioning System (PPS) PPS Y Z X 29

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

LGK PERFEXION radiation unit and collimator sector design

Collimator System for LGK PERFEXION 4, 8, 16 mm collimators No collimator helmets 192 Co-60 sources Cylindrical source geometry

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

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

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

Focus Pin Prick Film Test

How does weight effect results?

Results – PPS QA with Service Diode Test Tool

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: 0.52 + 0.82 + 0.22 mm =  1.0 mm

Time scale of radiation effects

 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

 Metastasis Clinical applications Malignant tumors  Glial tumors  Other malignant tumors Treatment 6 years

Before GK 39 months after GK F 3 y. Before radiosurgery glioblastoma

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

Clinical applications Glaucoma Four 8 mm isocenters

Clinical applications No of treated patients 1993-2009 10 538 Rok

Clinical applications Hospital Na Homolce 2004 -2008 Total No 4039 patients Oční AVM Funkční Benigní Maligní

DĚKUJI ZA POZORNOST