Highly precise treatment delivery Motion management method Tumour tracking ‘Dose painting’

1. WHO Classification. Louis D ; Acta Neuropathol 2007WHO Classification. Louis D ; Acta Neuropathol 2007
Introduction: Radiosurgery in brain tumourIntroduction: Radiosurgery in brain tumour
Total number of tumoursTotal number of tumours 132132
Total number of malignant glial tumour ~Total number of malignant glial tumour ~ 2020

2. Radiation therapyRadiation therapy
Conventional RT:
1.8-2 Gy/#
Majority of the tumours are treated with Conv RT
Hypofractionated RT:
>2 Gy/#
Mainly for palliative treatment
Radiosurgery:
Single fraction high dose treatment
Usually curative intent
Fractionated Radiosurgery:
Short course high dose treatment
Usually curative

3. Radiosurgery:Radiosurgery: toolstools
Gamma-Knife
LA based SRS Systems
BrainLAB
Novalis
Trilogy
Tomotherapy
CyberKnife

4. Gamma knifeGamma knife
• Gamma-knife: 201 Cobalt source
• Only for intracranial lesions
• Rigid/ fixed frame required
• Single fraction treatment

5. Gamma-knifeGamma-knife
Indications
- Small Meningiomas (<3 cm)
- Small acuastic schwannoma (<3 cm)
- Solitary / oligo brain metastasis with controlled primary (RPA Class I)
- Small residual LGG
- AVMs (<3 cm)
- Trigeminal neuralgia (Functional disorder)
More than 40 years experience / results with Gamma-Knife

6. CyberKnife:CyberKnife: Unique propertiesUnique properties
Highly precise treatment delivery
Motion management method
Tumour tracking
‘Dose painting’
Excellent dose distribution
Fractionation schedule
No rigid fixation

7. ‘CyberKnife is an extension of Gamma-Knife’
- Principles of ‘field arrangement’
- Dose distribution pattern
- Multiple isocentre
-Treatment principles
- Treatment delivery accuracy similar
- Delivered dose in single fractions
- Intra-cranial indications
CK & GK: Similarity
Hence, all the indications of GK are indications of CK also

8. CyberknifeCyberknife
Indications for single fraction treatment as Gamma-Knife
- Small Meningiomas (<3 cm)
- Small acuastic schwannoma (<3 cm)
- Solitary / oligo brain metastasis with controlled primary
- Small residual LGG
- AVMs (<3 cm)
- Trigeminal neuralgia
- Rec High grade glioma
- Craniopharyngioma
- Pituitary tumour
More than 40 years experience / results with Gamma-Knife

9. Cyberknife Vs Gamma-Knife:Cyberknife Vs Gamma-Knife: Dissimilarity
GK CK Comments
Immobilization device Rigid frame Orfit CK has favorable orfit
RT source Co60 6MV LA GK need to replace sources every
5/6 yrs
Planning No complex planning Inverse planning Favorable dosimetry in CK
Planning method Simple Complex Even neurosurgeons can plan in
GK
Isodose prescription Usually 50% Usually 80-95% GK: more dose heterogeniety
Fractions Single May treat multiple fraction Radiobiology favorable in CK
Tumour size Only smaller lesions can
be treated
Larger lesions also can be
treated in fractionated
schedule
Increased indications with CK
Energy source Radiation Electricity GK can work with less electricity
Verification Not possible Possible Even Intra-fraction movement can
be corrected
Indications Only brain lesions Both extra & intra cranial CK more economical

10. Cyberknife Vs Gamma-Knife:Cyberknife Vs Gamma-Knife: Dissimilarity
Advantage of Inverse planning
GK planning
CK planning
Dose to mesial temporal lobe & Choclea is higher with GK
Mean dose to mesial temporal lobe >6 Gy with SRS: IQ decline
Romanalli, Lancet 2009

11. % of patient with >10% drop in IQ% of patient with >10% drop in IQ
Left temporal lobe DVH
p=0.39
p=0.06
p=0.03
p=0.06
Volume(cc)
Jalali , Dutta et al IJROBP 2009

12. PTV margin in brain tumourPTV margin in brain tumour
CTV-PTV Margin
Systemic
Error (Σ)
Random
Error (σ)
ICRU 62 Strooms Van Herk’s
NR only Group:
Ant-Posterior 0.1 1.36 1.05 mm 1.15 mm 1.20 mm
Med-lateral 0.28 1.04 1.01 mm 1.29 mm 1.43 mm
Sup-Inferior 0.52 1.37 1.48 mm 2.0 mm 2.26 mm
NRF Group:
Ant-Posterior 2.24 1.28 3.14 mm 5.38 mm 6.50 mm
Med-lateral 0.78 1.41 1.77 mm 2.55 mm 2.94 mm
Sup-Inferior 0.94 1.39 1.91 mm 2.85 mm 3.32 mm
PTV margin: 3 mm.
Budrukkar , Dutta et al, JCRT 2008
Prospective study
Two different head rest (NR & NRF)
220images (NR 100, NRF 120)
Error estimation with 2D EPID

13. Cyberknife Vs Gamma-Knife Vs X-Knife:Cyberknife Vs Gamma-Knife Vs X-Knife:
CK: Accuracy similar with Gamma-Knife
Treatment delivery accuracy:
GK: ~1 mm
CK : ~1 mm
LA based SRS: 1-2 mm (iso-centric inacurracy; LUTZ test)
PTV margin:
CK: <1 mm
GK: <1 mm
LA based SRS: 1-2 mm
GK/CK LA based SRS
CK has the accuracy of GK and flexibility of LA based SRS

14. Indications for CyberKnifeIndications for CyberKnife
Intracranial tumours
1.‘oligo’ Brain metastasis
2.Acustic neuromas/ schwannomas
3.Meningiomas
4.Recurrent Low grade gliomas
5.Recurrent High grade gliomas
6. AVMs
7.Trigeminal neuralgias
8.Functional disorders
Extra-cranial tumours
1.Early Non small cell lung cancer
2.Localized Prostate cancer
3.Small volume Liver cancer
4.Inoperable Gall bladder, pancreas cancer
5.Recurrent head & neck cancer
6.Recurrent Ca nasopharynx
7.‘Oligo’ Lung metastasis.
8.‘Oligo’ Liver metastasis.
9.‘Oligo’ bone metastasis
10.Eye lesions / tumours

15. Radiosurgery in brain tumour: PromisesRadiosurgery in brain tumour: Promises
-
- Radiosurgery is a promising area in brain tumour management
-There is a definite role of radiosurgery with definite indications
-Radiosurgery is a short course, high dose radiation therapy
-Patient compliance is excellent, out-patient procedure
-CyberKnife is the most modern radiosurgery procedure