CyberKnife Radiosurgery

Question 1

Why do we use CyberKnife?

Answer 1

It is the only fully robotic radiation delivery system. Allows targeted beams from many different directions.
By precisely targeting tumour the Cyberknife can deliver high dose radiation directly to the tumour with sub-millimetre precision (limiting dose to healthy tissue).

Question 2

What are the advantages of CyberKnife?

Answer 2

Non-invasive and pain free
Typically completed in 1 to 5 treatment sessions.
Treatment times vary depending on the type of tumour being treated (many typically last 30 minutes).
Has tumour tracking that moves with respiration.
Tumour tracking capability and accuracy spares OAR and healthy tissue.
Alternative to surgery - does not require anaesthesia or overnight stay, eliminates recovery time and surgical risks
Patients can continue with normal daily activities after treatment.
Can be used for previously irradiated patients.

Question 3

What sites can CyberKnife treat?

Answer 3

Intracranial (Primary and Malignant lesions) 
Head and Neck 
Breast 
Lung 
Spine 
Liver 
Pancreas
Kidney 
Gynaecological/ Genitourinary
Prostate
Can also be used as a Virtual Brachytherapy Boost.

Question 4

Brain metastases Clinical Example?

Answer 4

15Gy prescribed to 75% isodose line.
Single Fraction
330 beams
60 minutes to treat.

Question 5

What are the different imaging technologies of the CyberKnife?

Answer 5

X-sight Lung tracking (LED markers & camera monitors external breathing motion).

When its not an intracranial or x-sight lung case a fiducual marker is placed in the tumour and this marker is tracked during treatment delivery.

Question 6

Lung Clinical Example?

Answer 6

54Gy prescribed tp 67%
3 fractions
91 beams
33 minutes to treat.

Question 7

Compare CyberKnife with Conventional RT for low grade prostate cancer.

Answer 7

Cyberknife vs Conventional RT.

TREATMENT PREP: 4 gold fiducual markers inserted into prostate (+/- SpaceOAR) VS. 3-4 fiducial markers inserted into prostate.

NUMBER OF TREATMENTS: 30-40 minutes VS. 10-15 minutes

NUMBER OF BEAMS: 100-200 VS. 5-7

DOSE (BED): 275Gy VS. 200Gy.

ACCURACY: < 1mm VS. Target area included prostate and 5-10mm margins to account for uncertainty.

SIDE EFFECTS: Mild to moderate urinary symptoms and mild fatigue lasting 1-2 months. VS. Mild urinary and bowel symptoms and fatigue lasting 2 months.

OUTCOMES: Long term control (10 years) VS. Long term control.

Question 8

Prostate Clinical Example?

Answer 8

36.25Gy prescribed to 81% isodose
5 fractions alternate days
145 beams
35 mins to treat.

Question 9

What are the advantages of CyberKnife for Rural Health patients.

Answer 9

7-8 week course of RT or surgery and recovery is reduced to 1 -5 treatments which can be completed in one week.

Time spent away from property and family is greatly reduced.

Time off from work greatly reduced. Employer benefits from not losing employee for extended periods of time.

Accommodation/ travel and other home away expenses costs are greatly reduced.

Possible side effects reduced.

Feasible alternative to surgery.

No waiting list - definitive treatment date.

Question 10

Liver Clinical Example:

Answer 10

45Gy prescribed to 77% isodose
3 fractions
98 beams
46 minutes to treat.

Question 11

Kidney Clinical Example:

Answer 11

39Gy prescribed to 70% isodose
3 fractions
110 beams
33 minutes to treat

Question 12

Pancreas Clinical Example

Answer 12

45Gy prescribed to 78% isodose
3 fractions
87 beams
46 minutes to treat.

Question 13

Adrenal Clinical Example

Answer 13

30Gy prescribed to 81% isodose
3 fractions
100 beams
32 minutes to treat

Question 14

Spine Clinical Example

Answer 14

24Gy prescribed to 75% isodose 
3 fractions alternate days 
120 beams 
35 minutes to treat. 
Spinal cord <18Gy for 0.35cc
Spinal cord <12.3Gy for 1.2cc