Installing Canada’s First BrainlabVero Stereotactic RT System:

Preparation, Licensing, Installation, Radiation Surveys, Head-Leakage Testing and More

M. Peter Petric1, Sheila MacMahon1, Marc J.P. Chamberland1, Eman Khawandanh1,2, Shadi Chitsazzadeh3

1BC Cancer Agency – Vancouver Cancer Centre2Saudi Arabian Cultural Bureau and National Guard Health Affairs – WR, Jeddah

3BC Cancer Agency – Vancouver Island Centre

BC Cancer Agency- 6 regional cancer centres + cancer research centre

- Provides a comprehensive cancer control program

for people in BC and the Yukon

- Vancouver Cancer Centre- 9 C-arm linear accelerators

- HDR and LDR brachytherapy

- Co-60 based TBI

- Proton ocular therapy (TRIUMF)

- PET/CT + production cyclotron

- VMAT / SRS / SRT / SBRT / gated treatments

Brainlab Vero- High precision stereotactic body

radiation therapy (SBRT) platform- Linear accelerator based

- Partnership between Brainlab AG and Mitsubishi

Heavy Industries

- First patients treated in 2011 in Japan

- Currently 21 units worldwide- 12 Japan / 1 South Korea / 6 Europe / 1 USA

- BC Cancer Agency unit is 1st in Canada!

Brainlab Vero

Brainlab Vero- Advanced imaging

- CBCT reconstruction in < 30s

- Stereo-diagnostic imaging system

- Automatic misalignment detection

- Treatment verification via MV portal beam imaging

-High precision dose delivery- 0.1 mm mechanical isocentre accuracy

- Coplanar and non-coplanar treatments possible

- Patient misalignments corrected using 6DOF couch

- Target tracking- Real-time tumor tracking of lung and liver tumors

Brainlab Vero vs Varian TrueBeamRadiation Safety Considerations

- Varian TrueBeam- Gantry rotation only

- Nominal head leakage = 0.1%

- No equipment rooms or pit

- Up to 20 MV

- Max dose rate = 2400 cGy/min

- Max field size = 40 x 40 cm2

- No beam-stop

- Brainlab Vero- Gantry & ring rotation and pan & tilt

gimbal

- Nominal head leakage = 0.2%

- Equipment rooms & large pit

- 6 MV only

- Max dose rate = 500 cGy/min

- Max effective field size = 24 x 24 cm2

- Beam-stop

Outside

Vault 4

Staff Stairwell

Corridor

Console

Preparation: Shielding- Pre-existing bunker designed for 6 MV C-arm linac

OutsideConsole

Preparation: Shielding- Pre-existing bunker designed for 6 MV C-arm linac

- C-arm linac primary shielding- Gantry rotation only

Preparation: Shielding

- Vero ring rotation & gimbal allows treatment beam to be

directed towards secondary shielding

- Also isocentre shift of 53 cm towards console due to large

Vero footprint

BUT

Beam-stop =

no primary beam

HOWEVER

low angle scatter

head leakage

Preparation: Shielding

NCRP 151 Shielding Calculations- Estimated patients per day: 20 (BCCA standard linac = 45)

- Estimated total workload: 35800 Gy/yr (BCCA standard = 62400 Gy/yr)

- Calculations included:

- Leakage (0.2%) and beam-stop transmission (0.1%)

- Scatter (used minimum scatter fractions at edges)

Preparation: Shielding

Outside

Vault 4

Staff Stairwell

Corridor

Console

OutsideConsole

Point Point DescriptionOccupancy Calculated Annual Dose (uSv) IDR

CommentsT Leakage Scatter Total (uSv/hr)

A Outside building 0.025 10.8 0.0 10.8 2.1

B Under staff stairs 0.025 0.5 0.0 0.5 0.1

C Staff stairwell (primary barrier) 0.025 0.0 0.0 0.0 0.0

D Staff stairwell (secondary barrier) 0.025 4.7 0.5 5.2 1.0

E Console closet (no maze wall) 0.05 6.1 0.0 6.1 0.5

F Console area 1 43.5 0.0 43.5 0.2 Controlled console area

G Vault door 0.125 31.5 10.7 42.2 1.0 Controlled vault door

G' Unit 4 console area 1 6.2 0.0 6.2 0.0

H Unit 4 vault front (secondary barrier) 0.5 56.9 4.9 61.8 0.5 In adjacent treatment vault

I Unit 4 vault (primary barrier) 0.5 0.0 0.1 0.1 0.0

J Dosimetry area (secondary barrier) 1 20.5 1.6 22.1 0.1

J' Interstitial space above 0.025 1.8 0.1 2.0 0.2

K Physicist office (CY) 1 0.0 0.1 0.1 0.0

Port Cable port next to vault door 0.125 31.5 0.1 31.6 1.0 Controlled vault door

Preparation: ShieldingNCRP 151 Shielding Calculations

Preparation: Equipment Rooms & Pit- 3 enclosed technical rooms required inside vault

Technical

rooms

Preparation: Equipment Rooms & Pit- And a sizeable pit under unit with 2 access hatches

Pit

Preparation: Equipment Rooms & Pit- Each enclosed room & the pit require:

- Independent Last-Person-Out (LPO) systems

- Beam indicator lights

- Emergency stop buttons

- In total need:- 5 LPO circuits

- 4 beam on indicator lights

- 10 emergency stop buttons

- 6 door interlock switches

Preparation: Equipment Rooms & Pit- Programmable Logic Controller (PLC) design

Preparation: Equipment Rooms & Pit- “Smart” LPO design

- Individual LEDs indicate LPO status

LED LPO

Status Indicator

Equipment Room LEDs Above Doors Pit LED

Preparation: Equipment Rooms & Pit- “Smart” LPO design

- Lit LED indicates LPO is NOT armed

LPO Armed

LPO NOT Armed

Preparation: Equipment Rooms & Pit- “Smart” LPO design

- Main vault LPO cannot be armed unless all equipment

rooms and pit LPO are armed

- Once all other LPOs armed main vault LPO turns green

Preparation: Licensing- Firsts for Brainlab

- Health Canada & CNSC Prescribed Equipment Certification

- CNSC Class II Service Licence

- CSA Certification

Preparation: Licensing- Firsts for Brainlab

- Health Canada & CNSC Prescribed Equipment Certification

- CNSC Class II Service Licence

- CSA Certification

Preparation: Licensing- Firsts for Brainlab

- Health Canada & CNSC Prescribed Equipment Certification

- CNSC Class II Service Licence Required for install!!!

- CSA Certification

Preparation: Licensing- Firsts for Brainlab

- Health Canada & CNSC Prescribed Equipment Certification

- CNSC Class II Service Licence

- CSA Certification

Installation- Vero is HEAVY!

- Nominal weight of lower O-ring 5000 kg

- I-beam & crane used to bring in Varian linacs into

building not sufficient

- Required last minute alternative route including shoring

up of floor beneath route

Installation- Vero is BIG!

- Upper and lower O-rings: 3.9 m 1.6 m 2.5 m

- Vault maze not wide enough to bring in pieces

- Required 30 cm portion of maze wall to be cut then re-

poured

Radiation Survey- Measurement details:

- Meters:- Fluke/Victoreen 451

- Reuter Stokes RSS-122

- Beam: 6 MV at max rep rate = 500 MU/min

- Estimated total workload = 35800 Gy/yr

- For each measurement point & gantry angle used max

dose rate to calculate annual dose - Worst case ring rotation & worst case gimbal tilt

Radiation Survey- Practical issues:

- degrees of freedom = survey measurement parameters

- Couch position limits max gantry rotation

- Vero gimbal resets to origin between every beam in service

mode & requires movement using pendant in room!

Measurements vs. Calculations

Radiation Survey

Point Point DescriptionOccupancy Max Measured Dose Rate (uSv/hr) Annual Dose (uSv) Max Dose Rate

T G0 G90 G270 G180 Measured Calculated (uSv/hr)

A Outside building 0.025 0.05 0.05 0.05 0.05 0.1 10.8 0.1

B Under staff stairs 0.025 0.05 0.05 0.2 0.05 0.3 0.5 0.2

C Staff stairwell (primary barrier) 0.025 0.1 0.05 0.11 0.05 0.2 0.0 0.1

D Staff stairwell (secondary barrier) 0.025 0.05 0.1 0.5 0.05 0.5 5.2 0.5

E Console closet (no maze wall) 0.05 0.05 0.1 0.1 0.05 0.4 6.1 0.1

F Console area 1 0.05 0.05 0.1 0.05 7.5 43.5 0.1

G Vault door 0.125 0.45 1.7 2.2 0.31 17.4 42.2 2.2

G' Unit 4 console area 1 0.13 0.25 0.4 0.1 26.3 6.2 0.4

H Unit 4 vault front (secondary barrier) 0.5 0.1 0.5 0.12 0.1 12.2 61.8 0.5

I Unit 4 vault (primary barrier) 0.5 0.05 0.1 0.05 0.05 3.7 0.1 0.1

J Dosimetry area (secondary barrier) 1 0.05 0.05 0.05 0.05 6.0 22.1 0.1

J' Interstitial space above 0.025 0.05 0.05 0.05 0.05 0.1 2.0 0.1

K Physicist office 1 0.05 0.05 0.05 0.06 6.3 0.1 0.1

Port Cable port next to vault door 0.125 0.8 0.9 1.4 0.81 14.6 31.6 1.4

Outside

Vault 4

Staff Stairwell

Corridor

Console

OutsideConsole

Head Leakage Testing- Localization of hot spots:

- Fujifilm Type C Computed Radiography IP cassettes

- Fujifilm FCR Profect CS CR-IR 363 CR reader

- 1000 MU delivered with MLC closed

- Position & orientation of cassettes marked on Vero

Head Leakage Testing- Localization of hot spots

Towards Beam

CR #A2

CR #A4

CR #A7

Towards Beam

MLC Tails

Hot Spots

Hot Spot

MLC Tails

Towards Beam

MLC Transmission

Head Leakage Testing- Dose rate at hot spots:

- Fluke/Victoreen 451 & Mirion DMC 3000 EPDs

- 100 MU delivered with MLC closed

- Max head leakage = 0.023%

- Manufacturer stated nominal head leakage = 0.2%

Beam-Stop Transmission Testing- Max gimbal tilt & pan used to cover beam-stop

- 1000 MU delivered with MLC fully open

Beam-Stop Transmission Testing- Localization of hot spots

Towards Isocentre

Towards Isocentre

Towards Isocentre

Towards Isocentre

Hot Spots

Beam-Stop Transmission Testing- Dose rate at hot spots:

- Max beam-stop transmission = 0.008%

- Manufacturer stated beam-stop transmission < 0.1%

Conclusions- Canada’s first Brainlab Vero successfully installed in

bunker designed for a conventional 6 MV C-arm linac

- “Smart” last-person-out system provides a convenient

solution for in-vault equipment rooms & pits

- Both head leakage and beam-stop transmission were

well below manufacturer’s specifications

- First BC Cancer Agency patient scheduled for

treatment with Vero in mid-June 2017

Acknowledgements- Special thanks to:

- John-Paul Sweeney: “Smart” LPO design & implementation

- Dr. Alanah Bergman: Lead physicist on Vero project

- Joel Beaudry, Ron Horwood, Claudia Mendez and

Vince Strgar: Physics Assistants

- Brainlab Vero Installers

- CNSC Class II Division

THANK-YOU

??? Questions ???