1. Doc.Ing. Josef Novotný,CSc
OLF

2. Synergy of medicine and technique
RADIOSURGERY
Synergy of medicine and technique

3. 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.

4. 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

5. 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

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

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

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

9. Stereotactic localization
MR indicator box
CT indicator box
DSA indicator box

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

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

12. 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

13. 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

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

15. 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

16. 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

17. Unlimited intracranial treatment reach
Leksell GammaPlan® PFX™

18. Arterio-venous malformation

19. Medieval “radiosurgery and radiotherapy”

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

21. 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

22. 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

23. Gamma Knife model B
Manual setting of coordinates
Trunnion fixation

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

25. 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

26. 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

27. 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

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

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

30. 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

31. LGK PERFEXION radiation unit and collimator
sector design

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

33. 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

34. 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

35. Service Diode Test Tool1 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

36. Focus Pin Prick Film Test

37. How does weight effect results?

38. Results – PPS QA with Service Diode Test Tool

39. 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

40. Time scale of radiation effects

41.  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

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

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

44. 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

45. Clinical applications
Glaucoma
Four 8 mm isocenters

46. Clinical applications
No of treated patients
Rok

47. Clinical applications
Hospital Na Homolce Total No 4039 patients
Oční
AVM
Funkční
Benigní
Maligní

49. DĚKUJI ZA POZORNOST