ViewRay System Commissioning
Kyle R. Padgett, PhD, DABR Assistant Professor University of Miami Viewray Team: Matt Studenski, PhD Chet Ford, PhD Yidong Yang, PhD Nesrin Dogan, PhD Medical Physics Residents: Naru Lamichhane, PhD Xing Li, PhD
Disclosures
• None
2
Overview • Overview of the MRIdian system • Commissioning
– Safety – MRI – Mechanicals – RT System – Treatment Planning System – End to End Testing
Introduction • Commonly known as Viewray
MRIdian • Integrated magnetic
resonance (MR)-guided radiation therapy (RT) instrument designed to provide simultaneous MR Imaging (MRI) and a range of external beam RT options
• Consists of three major sub-systems – MRI System – RT System – Adaptive RT System
The MRI • Gapped horizontal solenoidal superconducting
magnet • 0.35 T whole body MRI, capable of volumetric and
real-time imaging • The MRI system consists of two separate magnets
abutted with a 28 cm gap. • Split gradient coil has an inner diameter of 80 cm. • Resolution as low as 0.75 mm • Planar “real-time” imaging at up to 4 frames per
second. • MR isocenter matched to RT isocenter • Body & Surface coils are thin & uniformly attenuating
The MRI • Split Super Conducting Magnet
• Allows Unobstructed Beam Path • Fits in Standard Vaults, Pop-apart
design for non-destructive rigging • 0.35T Field strength provides 50cm
DSV for large FOV imaging • Less image distortion and less
patient heating • Minimal distortion of dose
distribution • 70cm bore to accommodate large
patients • Split gradient with a 28cm gap, slew
200mT/m/ms, 18mT/m peak, 30kW heat removal.
Low Field MRI
• High-field causes a loss of spatial
integrity
• Magnetic susceptibility artifacts
due to the patient scales with
field strength
• High field distorts the dose
distribution
• Electron return effects get
worse with field strength
• High field heats the patient -SAR
Electron Return Effect • The Magnetic Field has an effect upon the
secondary electrons • The stronger the Magnetic Field the more
pronounced the effect
Raaijmakers et. al. Phys. Med. Biol. 53 (2008) 909–923
MRI Sequences Available • FISP - Fast Imaging with Steady Precession • GE – Gradient Echo (Only one small FOV option) • FISP is a coherent technique that uses a fully balanced
gradient waveform (true FISP) • The image contrast is determined by T2*/T1 and mostly
depends on the TR • The speed and relative motion insensitivity of acquisition
help to make the technique reliable.
• Other MRI sequences may become available on future software releases.
Setup Imaging
• All setup images shown use FISP imaging
• FOV ranges from 22 – 54cm
• Resolution ranges from 1.5 – 3.0mm
• Acquisition time ranges from 23 – 170sec
• GE setup image has a resolution of 7.5mm, a FOV of ~27cm and a acquisition time of 12min
Real Time Imaging / Gating
• All CINE images shown use FISP imaging • FOV ranges from 27cm to 45cm • Resolution ranges from 3.5mm to 10mm • All are 4 frames per second for a single slice
The RT delivery system • Equipped with three robotic
60Co treatment heads mounted with 120° separation on a rotating gantry.
• Each treatment head operates independently and they can be operated simultaneously.
• Each head can deliver up to 1.8Gy per minute at the machine isocenter, which is 105 cm from each source, with the nominal source strength of 15kCi. The source is shielded by a depleted-uranium safe in the retracted position
The RT delivery system • Rotating Gantry Assembly • 3 Independent Co60 Headed Design
• Enabling IMRT, SBRT or 3D-Conformal External Beam Radiation with Asynchronous Delivery
• Mounted with 120 degree separation
• 15,000 Ci per source • +- 240 degree Rotation for 2 or 3
Head Operation for increased Reliability.
• 3 Doubly Focused MLC Systems • 180 MLC Leaves. 60 per head • 1.05 leaf thickness projected at
isocenter
Source Operation
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Beam Indicator
Beam Indicator
Beam OFF
Beam On
The MLC • 3 Doubly Focused MLC
Systems • 180 MLC Leaves Per Head • 1.05cm leaf thickness
projected at isocenter • Fully interdigitating • Average Leakage less than
0.375%
Adaptive RT System • An integrated high-performance radiation planning
and delivery software capable of auto contouring, Monte Carlo dose computation, and IMRT or conformal RT planning or both are used to support 3-dimensional conformal RT, IMRT, and on-couch ART.
• The speed of the TPS (9 field plans with complete optimization, leaf motion calculation, and dose calculations can be accomplished in less than 30 seconds) enables ART treatments based on the volumetric image of the day
Commissioning Equipment • Water tank with manually driven chamber holder • Non-magnetic ion chamber: Exradin Nonmagnetic
A28 & standard A12 chambers • MRI-compatible IMRT QA device: ArcCheck 1220-
MR, Sun Nuclear Corporation • MRI-compatible beam profiler: ArcCheck IC
Profiler 1122-mr, Sun Nuclear Corporation • Gafchromic Films and Film Processor • 2D Spatial Integrity Phantom • Spherical Water Phantoms • CIRS Gating Phantom • ACR MRI Phantom
Safety • Radiation shielding
survey was performed by the University of Miami radiation safety office. All points outside the treatment vault showed radiation levels in compliance with regulatory limits specified in 10 CFR, part 20 (limit of 2mR/hr)
Safety • Door Interlocks: Beam was successfully interrupted when door is opened
• Emergency stop buttons: The 5 emergency stop buttons were enabled and generated safety interlocks on the console
• Beam on Warning Light: Warning light successfully operated during irradiation
• Prime Alert Functionality: Prime alert functionality was confirmed with a check source
• Intercom and AV Monitoring: Confirmed with successful communication between two individuals
• Backup Timer: Primary timer was disabled and the backup timer successfully terminated the beam
• Emergency Door operation: Operates when power is off
• Emergency Couch Retract: Can be initiated manually and when power is off
• Many other safety interlocks were also tested during ATP
MRI Tests • Magnetic Field
Homogeneity • Phased Array Coil
Elements • Image Homogeneity • Spatial Integrity • High Contrast
Resolution
• Slice Thickness • Slice Position
Accuracy • Low Contrast
Resolution • Ghosting Ratio
Magnetic Field Homogeneity
Gantry 0 Gantry 30
Gantry 60
Gantry 90
Gantry 120
FWHM
<= 5ppm
1.53ppm 1.46ppm 1.44ppm 1.60ppm 1.74ppm
• The homogeneity of the MRI system was measured using a large spherical water phantom
• A water spectrum was then collected to determine the frequency spread at FWHM
• Repeated at several different Gantry Angles and with the different RF coils
Coil Element Tests
• The signal characteristics for the coil elements for all phased array coils were measured.
• 12 element Torso Coil • 12 element Head and Neck Coil
• All SNR measurements significantly exceeded specifications
• Shape of signal profile was also qualitatively evaluated.
Homogeneity • Homogeneity of the Body,
Torso, and H&N Coils were measured and exceeded specifications
• 60% Body Coil • 50% Torso Coil • 50% H&N Coil
• The Signal to Noise of the Body, Torso, and H&N Coils were measured and exceeded specifications
• SNR > 12 Body Coil • SNR > 30 Torso Coil • SNR > 30 H&N Coil
SNR = (ROI signal mean) * 0.66 / (ROI Noise SD) Uniformity % = 100 * 1 – [(ROI Signal max – ROI Signal min) / (ROI Signal max + ROI Signal min)]
Spatial Integrity
Pass-Rate 1mm Ring
Pass-Rate 2mm Ring
Max error
Axial 100.0% 100.0% 1.764mm Coronal 99.3% 98.7% 2.134mm Sagittal centered
100.0% 100.0% 1.298mm
Sagittal 12.5cm Patient Left
N/A 100.0% 1.387mm
Sagittal 12.5cm Patient Right
N/A 100.0% 1.060mm
• 2D spatial integrity was measured with a custom made phantom provided by Viewray
• All measurements within inner circle must have less than 1mm of distortion
• All measurements within outer circle must have less than 2mm of distortion
• This test is also performed in our Monthly QA
High Contrast Resolution
Figure 6: from ACR “Phantom Test Guidance for Use of the Small MRI Phantom”
• To assess the scanner’s ability to resolve small objects when the contrast to noise ratio is sufficiently high.
• Test utilizes the MRI ACR phantom • Should be able to visualize/resolve
several of the rows and columns of four. • This test is also performed in our
Monthly QA
Slice Thickness • To assess the accuracy with
which a slice of specified thickness is achieved
• Test utilizes the MRI ACR phantom
• Two signal ramps with a slope of 10 to 1 are utilized
• Thickness should be 5mm ± 0.7mm
• This test is also performed in our Monthly QA
Slice thickness = 0.2 x (top x bottom)/(top + bottom)
Slice Position Accuracy • To assess the accuracy with
which slices can be prescribed at specific locations
• Test utilizes the MRI ACR phantom
• Two crossed wedged ramps of 45 degrees are utilized
• The difference in the two bar length determines the slice position accuracy
• ½ of the measured length is the positional discrepancy
• This test is also performed in our Monthly QA
Low Contrast Resolution • To assess the extent to which
objects of low contrast are discernible in the images
• Test utilizes the MRI ACR phantom
• The low contrast disks are holes drilled in thin sheets of plastic mounted in the phantom
• Must find 9 spokes on 4 subsequent slices in both the T1 and T2 acquisitions
• This test is also performed in our Monthly QA
Ghosting Ratio • To assess the level of ghosting
in the images • Test utilizes the MRI ACR
phantom • ROIs are drawn inside the
phantom and in 4 surrounding areas to calculate the ghosting.
• Ratio must be less than 0.025 • This test is also performed in
our Monthly QA
Ghosting Ratio = [(top + btm) – (left + right)] / (2 x Large ROI)
Mechanicals • Couch Motions • Couch Level • Couch Sag • Couch orthogonal to
imaging plane • Laser / MRI
Coincidence
• Radiation / MRI Coincidence
• Radiation Isocentricity
• Gantry Angle Accuracy
Couch • Couch Motions • Couch Level: A level was placed on the couch oriented in the
transverse and longitudinal directions and recorded the values • Couch Sag: Solid Water was placed on Head Side and then Foot
Side and displacements measured with MRI 0.3mm Head 0.39 Foot • Couch motion vs MRI coordinates: Spatial Integrity Phantom was
imaged at two known locations then fused to demonstrate proper couch motion
• Couch orthogonal to MRI coordinates: Spatial Integrity Phantom was imaged in different orientations to confirm orthogonality
Radiation/MRI versus Laser Isocenter • The radiation versus laser
isocenter was determined by using the IC profiler and confirmed with starshots
• Laser and MRI coincidence was
determined with daily QA phantom and MRI visible fiducials. The offset was determined by measuring the fiducials location versus the isocenter location.
Sagittal Laser Offset Coronal Laser Offset Axial Laser Offset -0.7 mm 0.0 mm 0.8 mm
Gantry Radiation Isocenter
• 4 Starshots were collected at various gantry angles
• determine the size of the isocenter
• Laser / RT coincidence • Due to the design of the
system films cannot be placed at isocenter manually
• The Daily QA phantom has a circular film holder for this purpose but requires laser cut film
Gantry Angle Accuracy • Radiation beams were
delivered to the Arccheck device utilizing all three heads at various gantry angles and analyzed in the Arccheck software to determine gantry angle accuracy
• Gantry angles were also confirmed utilizing starshots collected on the Daily QA phantom
Head Set Angle VR Readout AC Measured
H1 330 330 330
H1 210 210 210
H2 330 330 330
H2 90 90 90.1
H3 210 210 210
H3 0 0 0.05
H3 90 90 90.1
MLC Leakage MLC leakage films were collected on all three heads at different gantry angles to ensure leakage is within tolerance and isn’t dependent on gantry rotation.
MLC Accuracy • Employs a wire jig with 4cm
separation between wires • Measures MLC positioning
accuracy • Align the wire jig to the
sagittal laser • Treatment plan was created
for a series of MLC segments centered at 0,-12,-8,-4,4,8,12cm
• The MLC positioning accuracy is ≤0.2cm
• In house software written to process data, see us at AAPM in Washington DC.
Field Size Accuracy • Square fields were
measured with the IC Profiler with a 1 cm depth (the intrinsic buildup of the IC Profiler device)
Field Size
Field Size Axis Head Gantry Flatness Symmetry Neg_Penumb Pos_Penumb Beam Center Field Size Difference (mm)
4.2x4.2 x-measured 1 0 22.4 1.8 1.46 1.31 0.01 4.18 0.2
x-measured 3 0 22 1.8 1.44 1.29 0.02 4.25 0.5
4.2x4.2 Y-measured 1 0 20.8 -3.8 1.24 1.48 0.02 4.16 0.4
Y-measured 3 0 24.8 -8.8 1.25 1.45 0.12 4.22 0.2
10.5x10.5 X-measured 1 0 10.2 0.6 1.56 1.41 0 10.49 0.1
X-measured 3 0 9.8 0.6 1.54 1.38 0.01 10.58 0.8
10.5x10.5 Y-measured 1 0 9.5 -1.1 1.37 1.62 0.02 10.55 0.5
Y-measured 3 0 11.3 -1.4 1.38 1.58 0.12 10.54 0.4
21x21 X-measured 1 0 2.3 0.2 1.67 1.51 0.01 20.86 1.4
X-measured 3 0 2.3 0.1 0.48 0.48 0 20.96 0.4
21x21 Y-measured 1 0 2.1 -0.3 1.47 1.69 -0.02 20.89 1.1
Y-measured 3 0 2.2 -0.2 1.46 1.67 0.09 20.93 0.7
27.3x27.3 X-measured 1 0 2.7 0.2 1.74 1.57 0 27.21 0.9
X-measured 3 0 2.7 0.1 1.72 1.55 0.01 27.29 0.1
27.3x27.3 Y-measured 1 0 2.8 -0.3 1.54 1.77 0 27.22 0.8
Y-measured 3 0 2.8 -0.2 1.56 1.72 0.11 27.25 0.5
4.2x4.2 x-measured 1 90 21 2.4 1.39 1.31 -0.04 4.2 0
x-measured 2 90 22.2 4.1 1.37 1.3 -0.08 4.29 0.9
x-measured 3 90 20.8 2.4 1.37 1.29 -0.04 4.27 0.7
4.2x4.2 Y-measured 1 90 22.3 3.1 1.5 1.25 0.04 4.18 0.2
Y-measured 2 90 23.4 3.5 1.44 1.31 -0.1 4.22 0.2
Y-measured 3 90 23.2 3.7 1.45 1.29 -0.08 4.22 0.2
10.5x10.5 X-measured 1 90 8.7 0.3 1.52 1.43 -0.03 10.52 0.2
X-measured 2 90 9.3 0.6 1.5 1.42 -0.07 10.61 1.1
X-measured 3 90 8.6 0.4 1.49 1.4 -0.04 10.6 1
10.5x10.5 Y-measured 1 90 10.1 0.8 1.61 1.37 0.04 10.54 0.4
Y-measured 2 90 11.2 1.2 1.57 1.4 -0.13 10.53 0.3
Y-measured 3 90 10.9 1 1.57 1.38 -0.09 10.57 0.7
21x21 X-measured 1 90 2.2 -0.3 1.64 1.53 -0.04 20.91 0.9
X-measured 2 90 2.4 -0.2 1.62 1.52 -0.09 21 0
X-measured 3 90 2.1 -0.3 1.62 1.5 -0.04 20.98 0.2
21x21 Y-measured 1 90 2.5 0.3 1.72 1.47 0.05 20.89 1.1
Y-measured 2 90 2.8 0.1 1.69 1.47 -0.09 20.97 0.3
Y-measured 3 90 2.5 0.1 1.68 1.45 -0.07 20.94 0.6
27.3x27.3 X-measured 1 90 3 -0.4 1.69 1.61 -0.04 27.27 0.3
X-measured 2 90 3.1 -0.3 1.67 1.61 -0.09 27.35 0.5
X-measured 3 90 2.9 -0.4 1.67 1.58 -0.03 27.34 0.4
27.3x27.3 Y-measured 1 90 2.9 0.2 1.78 1.52 0.02 27.22 0.8
Y-measured 2 90 3 0.2 1.75 1.54 -0.12 27.28 0.2
Y-measured 3 90 2.7 0 1.72 1.53 -0.1 27.26 0.4
Output Calibration • A28 MRI compatible chambers
employed
• Calibration conditions: 5 cm depth in solid-water 105 cm SAD, 10.5 x 10.5 cm field.
• Beams delivered from 90 degrees in solid water phantom
• For verification, heads 1 and 3 were measured in liquid water at 0 degrees (AP beam), and these measurements matched the measurements in solid water to less than a 0.5% difference.
RPC OSLDs Report
Percent Depth Doses A28 TPS-measured
depth (mm) 4.2x4.2 10.5x10.5 27.3x27.3
3.26 1.18% 0.90% 2.94%
8.26 0.00% 0.00% 0.00%
18.26 -0.23% -0.11% -0.12%
28.26 0.03% -0.44% -0.02%
38.26 0.11% -0.46% -0.04%
48.26 -0.03% -0.66% 0.05%
68.26 0.18% 0.14% 0.12%
98.26 0.06% -0.17% 0.07%
148.26 -0.01% -0.67% 0.35%
198.26 1.39% -0.87% 0.14%
0.00%
10.00%
20.00%
30.00%
40.00%
50.00%
60.00%
70.00%
80.00%
90.00%
100.00%
0 50 100 150 200
Perc
ent D
epth
Dos
e
Depth (mm)
Measured vs TPS
4.2 x 4.2 TPS
10.5 x 10.5 TPS
27.3 x 27.3 TPS
4.2 x 4.2 Measured
10.5 x 10.5 Measured
27.3 x 27.3 Measured
Beam Profiles • Profiles with different depths of
solid water • Three depths (1,5, and 10cm)
with detector plane maintained at Iso (105cm SAD)
• 4.2x4.2 cm, 10.5x10.5 cm, 21.0x21.0 cm, and 27.3x27.3 cm field sizes were measured
• Same profiles were exported from the TPS and the profiler software was used to calculate the flatness and symmetry
• All profiles matched within specifications
Depth = 10 cm Field Size Axis Head Gantry Flatness %Diff Symmetry %Diff 4.2x4.2 X-measured 1 90 22.6 -0.1 3.5 6.2
X-measured 2 90 23.4 0.7 3.6 6.3
X-measured 3 90 23.2 0.5 3.5 6.2
X-calc 22.7 -2.7 4.2x4.2 Y-measured 1 90 20.2 1.2 2.5 2.5
Y-measured 2 90 20.9 1.9 3.7 3.7
Y-measured 3 90 19.5 0.5 1.8 1.8
Y-calc 19 0 10.5x10.5 X-measured 1 90 11.2 0.3 0.8 0.2
X-measured 2 90 11.9 1 1.1 0.5
X-measured 3 90 11.6 0.7 1 0.4
X-calc 10.9 0.6 10.5x10.5 Y-measured 1 90 10 1.3 0.5 0.7
Y-measured 2 90 10.3 1.6 0.8 1
Y-measured 3 90 9.4 0.7 0.5 0.7
Y-calc 8.7 -0.2 21.0x21.0 X-measured 1 90 5.5 0.4 0.2 0.2
X-measured 2 90 5.9 0.8 0.1 0.1
X-measured 3 90 5.6 0.5 0.2 0.2
X-calc 5.1 0 21.0x21.0 Y-measured 1 90 5.3 0.1 0 -0.1
Y-measured 2 90 5.5 0.3 0.2 0.1
Y-measured 3 90 5.3 0.1 0.1 0
Y-calc 5.2 0.1 27.3x27.3 X-measured 1 90 6.3 0.2 0.2 0
X-measured 2 90 6.6 0.5 0.4 0.2
X-measured 3 90 6.4 0.3 0.3 0.1
X-calc 6.1 0.2 27.3x27.3 Y-measured 1 90 6 0 0 0.1
Y-measured 2 90 6.2 0.2 0.2 0.3
Y-measured 3 90 6 0 0.2 0.3
Y-calc 6 -0.1 27.3x27.3 X-measured 1 0 6.3 0.2 0.2 0.3
X-measured 3 0 6.3 0.2 0.1 0.2
X-calc 6.1 -0.1 27.3x27.3 Y-measured 1 0 6.3 0.2 -0.1 0.2
Y-measured 3 0 6.1 0 -0.3 0
Y-calc 6.1 -0.3 27.3x27.3 X-measured 2 270 6.6 0.5 -0.5 -0.3
X-measured 3 270 6.5 0.4 -0.5 -0.3
X-calc 6.1 -0.2 27.3x27.3 Y-measured 2 270 6.2 0.2 0.3 0.2
Y-measured 3 270 6.1 0.1 0.3 0.2
Y-calc 6 0.1
Shutter Timer Error
• A28 chamber was irradiated several times for two different durations (30s and 240s)
Shutter Dose Compensation
• 𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷 𝐶𝐶𝐷𝐷𝐶𝐶𝐶𝐶𝐷𝐷𝐶𝐶𝐷𝐷𝐶𝐶𝐶𝐶𝐶𝐶𝐷𝐷𝐶𝐶 = 1𝑠𝑠 𝑛𝑛𝑛𝑛−200𝑠𝑠 𝑛𝑛𝑛𝑛/200200𝑠𝑠 𝑛𝑛𝑛𝑛/200
• An A28 chamber was irradiated several times for two different lengths of time (200seconds and 1second) and the compensation time is calculated using the equation shown above
• Compensation values from the configuration file was recorded and compared to the calculated value
Timer Accuracy
• A 30-second exposure was delivered for each beam. Exposure time was verified with a stopwatch with NIST-traceable calibration.
Head Set Time Measured
Time Percent Error
1 30 30.2 0.67%
2 30 30.15 0.50%
3 30 30.2 0.67%
Timer Linearity
Exposures of 5, 15, 30 and 60 seconds were measured with an ion chamber at 1.5 cm depth in solid water. The measured exposures were fit to a line and the line fit was compared to the measured value for each time.
Time (s) 5 s 15 s 30 s 60 s 5 15 30 60 5 s 15 s 30 s 60 s
H1 3.19 9.59 19.18 38.34 3.197 9.587 19.17 38.34 -0.204 0.0317 0.0386 -0.0102 -0.00204
H2 3.16 9.49 18.97 37.94 3.163 9.486 18.97 37.94 -0.0894 0.042 -0.0042 -0.001 -0.00195
H3 3.18 9.54 19.07 38.14 3.181 9.537 19.07 38.14 -0.041 0.0274 -0.008 0.0006 -0.00513
Shutter Timer Error (sec)
H Rdg Fit % Difference
Meas-Fit
Gating Latency • CIRS motion phantom • Sensor is placed a known
distance inferior to the most superior extent of motion
• Beam should trigger off when motion phantom reaches the level of this optical sensor
• Latency is discrepancy between actual beam off and optical sensor triggering.
• Measured with a four channel oscilloscope.
Gating Dosimetry
Couch Attenuation
Gantry Angle
Rela
tive
Atte
nuat
ion
TPS Statistics
Max Dose Min Dose Mean Dose Standard Deviation 1-Million Histories 10.64 8.94 9.90 0.18 16-Million Histories 10.20 9.78 9.98 0.04
• Viewray utilizes a Monte Carlo based treatment planning system
• The number of particle histories used in the calculation increases the accuracy, but…
• Using a high # of histories in adaptive planning can significantly increase the amount of time the patient is on the table.
End to End Tests • IMRT Delivery • IMRT Two Head Delivery • RPC Head and Neck Phantom • RPC Lung Phantom • TG-119 Tests
– Head and Neck – Prostate – Multi Target – C-Shape
IMRT Delivery Delivery Mode Gamma (3%, 3mm)
Full Delivery Measured to Calculated Dose 99.4 %
Interrupted Delivery: Measured to Calculated 100 %
Interrupted Delivery: Measured to Measured 99.9 %
IMRT Two-Head Mode Delivery Mode Gamma (3%, 3mm)
Full Delivery Measured to Calculated Dose 99.4 %
Two Head Mode: (Two Head Mode) Measured to (Three Head Mode) Calculated
99%
(Two Head Mode) Measured to (Three Head Mode) Measured
100%
RPC Head and Neck
Primary PTV Rx 6.6Gy
Secondary PTV Rx 5.4Gy
OAR Max 4.5Gy
Normal Tissue 7.26Gy
RPC Head and Neck Constraints
Primary PTV Rx 6.6Gy
Secondary PTV Rx 5.4Gy
OAR Max 4.5Gy
Normal Tissue 7.26Gy
RPC Head and Neck
RPC Lung
Primary PTV Rx 6.0Gy
Cord Max 5.0Gy
Heart <33% 6.0Gy
Heart <66% 4.5Gy
Heart <100% 4.0Gy
Both Lungs <37% 2.0Gy
RPC Lung Constraints Primary PTV Rx 6.0Gy
Cord Max 5.0Gy
Heart <33% 6.0Gy
Heart <66% 4.5Gy
Heart <100% 4.0Gy
Both Lungs <37% 2.0Gy
RPC Lung
TG-119 Summary Test Gamma (2.5%/2.5mm)
Head and Neck 95%
Prostate 97.4%
Multitarget 98.2%
C-Shape 96.3%
Acknowledgements • Alan Pollack, MD PhD • Radka Stoyanova, PhD • Viewray Inc: David Holloway, Maria Bellon,
Rebecca Sandbrook, James Victoria, Michael Saracen, John Ryan
• UCLA: Minsong Cao and James Lamb
• WashU: Olga Green