8/3/2019 Presentation Rros
1/31
Neutron Dosimetry in
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble Detector
Characterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Neutron Dosimetry in Radiotherapy
Kristian Ytre-Hauge
Department of Physics and TechnologyUniversity of Bergen
August 2009
http://-/?-http://-/?-http://find/http://goback/http://-/?-http://-/?-8/3/2019 Presentation Rros
2/31
Neutron Dosimetry in
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble Detector
Characterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Introduction
About 50% of all cancer patients receive radiotherapy
http://find/http://goback/http://-/?-8/3/2019 Presentation Rros
3/31
Neutron Dosimetry in
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble Detector
Characterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Introduction
About 50% of all cancer patients receive radiotherapy
The aim of radiotherapy is to damage cancer cells whilesparing healthy tissue
http://goforward/http://find/http://goback/http://-/?-8/3/2019 Presentation Rros
4/31
Neutron Dosimetry in
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble Detector
Characterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Introduction
About 50% of all cancer patients receive radiotherapy
The aim of radiotherapy is to damage cancer cells whilesparing healthy tissue
Most common is the use of an external photon beam
http://goforward/http://find/http://goback/http://-/?-8/3/2019 Presentation Rros
5/31
Neutron Dosimetry in
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble Detector
Characterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Introduction
About 50% of all cancer patients receive radiotherapy
The aim of radiotherapy is to damage cancer cells whilesparing healthy tissue
Most common is the use of an external photon beam Hadron therapy is an alternative which has received increasing
interest over the last decades
http://goforward/http://find/http://goback/http://-/?-8/3/2019 Presentation Rros
6/31
Neutron Dosimetry in
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble Detector
Characterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Introduction
About 50% of all cancer patients receive radiotherapy
The aim of radiotherapy is to damage cancer cells whilesparing healthy tissue
Most common is the use of an external photon beam Hadron therapy is an alternative which has received increasing
interest over the last decades
Neutrons are produced during the treatment and contributeto a higher dose in healthy tissue
http://goforward/http://find/http://goback/http://-/?-8/3/2019 Presentation Rros
7/31
Neutron Dosimetry in
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble Detector
Characterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Linear accelerator for radiotherapy with photons
Photon energies between 6 and 18 MeV are the mostcommon to use
http://goforward/http://find/http://goback/http://-/?-8/3/2019 Presentation Rros
8/31
Neutron Dosimetry in
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble Detector
Characterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Neutron contamination of the photon beam
Neutrons are mainly produced through (,n) reactions in the
high-Z material used for shielding and shaping the photonbeam
http://goforward/http://find/http://goback/http://-/?-8/3/2019 Presentation Rros
9/31
Neutron Dosimetry in
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble Detector
Characterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Neutron contamination of the photon beam
Neutrons are mainly produced through (,n) reactions in the
high-Z material used for shielding and shaping the photonbeam
http://goforward/http://find/http://goback/http://-/?-8/3/2019 Presentation Rros
10/31
Neutron Dosimetry in
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble Detector
Characterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Principles of hadron therapy
Protons, 12C-ions or other ions are accelerated to energies upto about 400 MeV/u
http://goforward/http://find/http://goback/http://-/?-8/3/2019 Presentation Rros
11/31
Neutron Dosimetry in
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble Detector
Characterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Secondary particles from hadron therapy
Neutrons, protons and fragments lighter than the primaryparticles are produced through nuclear reactions and maycontribute to dose outside the target volume
http://goforward/http://find/http://goback/http://-/?-8/3/2019 Presentation Rros
12/31
Neutron Dosimetry in
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble Detector
Characterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Dosimetry
Absorbed dose (D)Defined as the energy deposited per unit mass, D = E
m
The unit for absorbed dose is the Gray [Gy]
http://goforward/http://find/http://goback/http://-/?-8/3/2019 Presentation Rros
13/31
Neutron Dosimetry in
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble Detector
Characterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Dosimetry
Absorbed dose (D)Defined as the energy deposited per unit mass, D = E
m
The unit for absorbed dose is the Gray [Gy]
Equivalent dose (HT)The absorbed dose is weighted by a quality factor dependingon the type of radiationHT = wRDR
The unit for equivalent dose is the Sievert [Sv]
N D i i
http://goforward/http://find/http://goback/http://-/?-8/3/2019 Presentation Rros
14/31
Neutron Dosimetry in
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble Detector
Characterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Neutron detectors
BF3 proportional counter
3He proportional counter
6
Li-based scintillators Thin film breakdown counter - Fission counter
Thermoluminescence detectors
Bubble detectors
N t D i t i
http://goforward/http://find/http://goback/http://-/?-8/3/2019 Presentation Rros
15/31
Neutron Dosimetry in
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble Detector
Characterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Physical principles of bubble detectors
Superheated droplets dispersed throughout a clear plasticpolymer
Neutron Dosimetry in
http://goforward/http://find/http://goback/http://-/?-8/3/2019 Presentation Rros
16/31
Neutron Dosimetry in
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble Detector
Characterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Physical principles of bubble detectors
Superheated droplets dispersed throughout a clear plasticpolymer
A liquid is said to be superheated if it continues to exist inthe liquid state above its normal boiling point
Neutron Dosimetry in
http://goforward/http://find/http://goback/http://-/?-8/3/2019 Presentation Rros
17/31
Neutron Dosimetry in
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble Detector
Characterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Physical principles of bubble detectors
Superheated droplets dispersed throughout a clear plasticpolymer
A liquid is said to be superheated if it continues to exist inthe liquid state above its normal boiling point
The droplets are vaporized into bubbles if sufficient energy isdeposited in the droplet
Neutron Dosimetry in
f
http://goforward/http://find/http://goback/http://-/?-8/3/2019 Presentation Rros
18/31
Neutron Dosimetry in
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble Detector
Characterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Physical principles of bubble detectors
Superheated droplets dispersed throughout a clear plasticpolymer
A liquid is said to be superheated if it continues to exist inthe liquid state above its normal boiling point
The droplets are vaporized into bubbles if sufficient energy isdeposited in the droplet
The number of bubbles is proportional to the equivalent dose
Neutron Dosimetry in
B bbl D S (BDS)
http://goforward/http://find/http://goback/http://-/?-8/3/2019 Presentation Rros
19/31
y
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble Detector
Characterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Bubble Detector Spectrometer (BDS)
6 different energy thresholds
Neutron Dosimetry in
B bbl D S (BDS)
http://goforward/http://find/http://goback/http://-/?-8/3/2019 Presentation Rros
20/31
y
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble Detector
Characterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Bubble Detector Spectrometer (BDS)
6 different energy thresholds
Unfolding of the response from all the subgroups gives aneutron energy spectrum represented by a 6-region histogram
Neutron Dosimetry in
Ph t b t
http://goforward/http://find/http://goback/http://-/?-8/3/2019 Presentation Rros
21/31
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble Detector
Characterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Photon beam setup
The bubble detectors were placed inside the phantom and a15 MeV photon beam applied
Neutron Dosimetry in
T t d d f th BDS d t t
http://goforward/http://find/http://goback/http://-/?-8/3/2019 Presentation Rros
22/31
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble Detector
Characterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Temperature dependence of the BDS detectors
The response from the BDS detectors was measured at 15
,20
and 25
Neutron Dosimetry in
R di hTe e at e de e de ce of the BDS detecto s
http://goforward/http://find/http://goback/http://-/?-8/3/2019 Presentation Rros
23/31
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble Detector
Characterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Temperature dependence of the BDS detectors
The response from the BDS detectors was measured at 15
,20
and 25
An increase in the temperature of 5
can lead to an increasein the response of more than 100%
Neutron Dosimetry in
RadiotherapMeasurement setup in the isocenter plane
http://goforward/http://find/http://goback/http://-/?-8/3/2019 Presentation Rros
24/31
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble DetectorCharacterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Measurement setup in the isocenter plane
without the phantom
Neutron Dosimetry in
RadiotherapyComparison of the obtained neutron spectrum
http://goforward/http://find/http://goback/http://-/?-8/3/2019 Presentation Rros
25/31
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble DetectorCharacterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Comparison of the obtained neutron spectrum
with Monte Carlo simulations
Energy [MeV]-210 -110 1 10
Fluence[n/(cm2
Gy)]
610
710
810
Neutron spectrum measured with the BDS in the isocenter plane without the phantom
Neutron Dosimetry in
RadiotherapyResults from the photon beam measurements
http://goforward/http://find/http://goback/http://-/?-8/3/2019 Presentation Rros
26/31
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble DetectorCharacterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Results from the photon beam measurements -
Dose
Placement of detectors1 2 3 4 5 6 7 8
Neutrondose[mSv/Gy]
0
2
4
6
8
10
12
141 - Isocenter plane
2 - MC simulations isocenter plane
3 - Position 8
4 - Position 8 Closed MLCs
5 - Position 9
6 - Position 9 closed MLCs
7 - Position 14
8 - Position 15
Neutron dose for various positions
Neutron Dosimetry in
RadiotherapyCarbon Beam Measurements Setup
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27/31
Radiotherapy
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble DetectorCharacterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Carbon Beam Measurements - Setup
Neutron Dosimetry in
RadiotherapyConclusion
http://goforward/http://find/http://goback/http://-/?-8/3/2019 Presentation Rros
28/31
py
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble DetectorCharacterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Conclusion
Bubble detectors are a good alternative to measure neutrondoses in radiotherapy
Neutron Dosimetry in
RadiotherapyConclusion
http://goforward/http://find/http://goback/http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-8/3/2019 Presentation Rros
29/31
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble DetectorCharacterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Conclusion
Bubble detectors are a good alternative to measure neutrondoses in radiotherapy
The bubble detectors sensitivity varies strongly withtemperature
Neutron Dosimetry in
RadiotherapyConclusion
http://goforward/http://find/http://goback/http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-8/3/2019 Presentation Rros
30/31
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble DetectorCharacterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Conclusion
Bubble detectors are a good alternative to measure neutrondoses in radiotherapy
The bubble detectors sensitivity varies strongly withtemperature
Neutron doses from photons were found to be in the order ofmSv per Gray
Neutron Dosimetry in
Radiotherapy
http://goforward/http://find/http://goback/http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-8/3/2019 Presentation Rros
31/31
Kristian Ytre-Hauge
Department of Physics
and Technology
University of Bergen
Introduction
Radiotherapy with
Photons
Radiotherapy with
Hadrons
Dosimetry
Neutron Detectors
Bubble DetectorCharacterization
Neutron Spectra in the
Medical Linac Room
Carbon Beam
Measurements
Conclusion
Thank you!
http://goforward/http://find/http://goback/http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-Top Related