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Treatment Verification with Cherenkov Imaging
Brian W Pogue PhD MacLean Professor of Engineering, Dartmouth
Editor-in-Chief, Journal of Biomedical Optics
Dose imaging?Beam Tracking Cherenkov emission from eye
Disclosures
DoseOptics LLC: President and co-founder
Developing Cherenkov imaging cameras software and systems.
LINAC Radiation Dose produces pulses with Cherenkov light
Characteristic spectrum
Cherenkov in tissue
oxygenated De-oxygenated
Cherenkovemission
Tissue phantom 1% blood +
1% Intralipid
Axelsson et al, Med. Phys. 2010Zhang et al, Med. Phys. 2012
Cherenkov spectroscopy
Linac
(Cherenkov)
pulses
Cherenkov frame
Background frame
TimeC
am
era
ga
tin
g
Ambient room light
Time-gated Intensified Camera System
Time-gatedImage
Intensifier
CMOSCamera
FPGABoard
USB3 in/out
DISCLOSURE: B. Pogue is founder & president of DoseOptics.
Single photon imagingwith room lights on!
Petr Bruza Mike JermynVenkat Krishnaswamy Bill Ware Cedar Farwell
Linac
(Cherenkov)
pulses
Cherenkov frameBackground frame
Time
Ca
me
ra
ga
tin
g
Relay lens
FarzeenChristie
Cameras installed in all Dartmouth Linac Rooms
AdditionalUser sites:DartmouthU PennWash UEmoryHarvard/MGH
Verification of
beam positionon the
patient
Cherenkov is a direct display of surface dose
Miao et al, Med. Phys. 2019
Light Field Cherenkov FILM
CherenkovFILM
Cherenkov
Confidential DoseOptics LLC
Live Cherenkov Cumulative Cherenkov
Planned Treatment Area Planned Cumulative Surface Dose
Whole breast radiotherapy verification
Incidents observed with Cherenkov images
Day 1
1050
‘arm down’ treatments on different days
Jarvis et al, IJROBP (in review 2020)
Day 2
Day 3 Day 4
R Hachadorian, et al,
Session:Multi-Disciplinary ePoster
Poster #: PO-GeP-M-194
Contralateralbreast
Contralateralbreast
shoulder
Incidents observed with Cherenkov images
Day 1
104 105
Day 2
Neck involvementBolus placement differences
Jarvis et al, IJROBP (in review 2020)
R Hachadorian, et al,
Session:Multi-Disciplinary ePoster
Poster #: PO-GeP-M-194
11/10
Match line views from Cherenkov on skin
Hachadorian et al, submitted 2020
R Hachadorian, et al
Session Title: Multi-Disciplinary ePoster
Poster #: PO-GeP-M-75
Supraclavicular field Tangent field
Match region
Head and Neck Tumor Treatments
Planned dose
Imaged signal
Real time view of treatment
Treatment Plan
Dan Alexander
Cherenkov ≈ Surface Dose ?
X-ray dose builds up & Cherenkov is emitted
(b) (c)
Build up is always linear over the first 8 mm!!
𝜑𝑅 𝑧 = 𝑆(𝑧)3𝜇𝑠
/
𝜇𝑎𝑒−𝜇𝑒𝑓𝑓𝑧 S(z) = S0 (k1 + k2z)
𝜑𝐶ℎ 𝑧 =𝑆0 𝑘1
𝐷𝜇𝑒𝑓𝑓𝑒−𝜇𝑒𝑓𝑓𝑧 −
𝑆0 𝑘2
2𝐷𝜇𝑒𝑓𝑓2 (𝑒
−𝜇𝑒𝑓𝑓𝑧 − 𝑒𝜇𝑒𝑓𝑓𝑧)
Pogue et al, Proc SPIE BiOS 2020
Signal is dependent upon:• Build up rate with depth• Absorption coefficient (≈blood volume)
Cherenkov emission is decreases with CT number!
Higher CT number ≈ higher blood vol(blood attenuates light)
IC(E) = c(CT,E) ∙ IR(E)
Blue Ribbon ePoster
Poster Number: BReP-SNAP-M-87
I. Tendler et al, IJROBP 2020YOUNG INVESTIGATOR SYMPOSIUM
Session: MO-CD-TRACK 1-2
AutomatedNon-contact
Dose readout
back delivery
Stanford Technique
front delivery
T Miao & T. Zhu
Blue Ribbon ePoster
BReP-SNAP-M-141
Prof Tim Zhu UPenn
Cumulative Dose-Rate Histogram
XY
Z
Scre
en
Spot Scanning
Radioluminescence Imaging of Proton Beam DoseDose Rate Dynamics Volumetric LET and Dose Patient Plan Imaging
Op
tic
al
Relative Dose
70 MeV 150 MeV100 MeV
M Rahman: Therapy General
ePoster PO-GeP-T-388
Summary of observations:
• Cherenkov imaging allows real time view of delivery & incidentsneck, shoulder, contralateral, bolus, plan incidents
• Quantitative dose imaging with CT and optical corrections
• Match lines can be visualized at adjacent fields
• Absolute dose point values obtained with scintillator imaging
• Total skin electron therapy mapping is possible
• Small beam dosimetry
• Proton beam dosimetry via scintillation