Presenter of 1 Presentation
CALORIMETRY FOR ULTRA-HIGH-DOSE-RATE VERY HIGH ENERGY ELECTRON BEAMS
Abstract
Background and Aims
In the process of establishing calorimetry as a primary standard for Very High Energy Electrons (VHEEs), measurements were performed in an ultra-high-dose-rate (UHDR) VHEE beam using the CLEAR facility at CERN. VHEEs with energies up-to 200 MeV could provide various benefits over standard clinical energy electron beams including increased conformity, deep-seated and complex tumour treatment as well as beam scanning and focusing.
Methods
The National Physical Laboratory graphite calorimeter, designed for Intensity Modulated Radiotherapy (IMRT), measured dose-to-graphite up-to approximately 5 Gy/pulse with dose-to-water calculated by application of a preliminary graphite-to-water conversion factor determined using the Geant4 Monte Carlo code. The CLEAR beamline allowed for investigation of both clinical dose-rate and UHDR regimes through tuning of the number of electron bunches per-pulse and the charge-per-bunch.
Results
As a result, the instantaneous dose-rate ranged between 5x106 Gy/s and 3.1x108 Gy/s whilst pulse widths ranged from 666 ps (1 bunch-per-pulse) to 133.2 ns (200 bunches-per-pulse). The dose-per-pulse ranging from 0.03 Gy/pulse to 5.26 Gy/pulse was found to increase linearly with increasing charge-per-pulse with R2=0.98 .
Conclusions
These calorimetry measurements allowed for absolute determination of ionisation chamber correction factors applicable to clinical dosimetry protocols. Moreover, a full uncertainty budget including calorimeter vacuum gap correction and perturbation factors is currently being developed such that the translation of UHDR VHEE beams to the clinical setting can be accelerated.
This project 18HLT04 UHDpulse has received funding from the EMPIR programme co-financed by the Participating States and from the European Union’s Horizon 2020 research and innovation programme.
Author Of 1 Presentation
CALORIMETRY FOR ULTRA-HIGH-DOSE-RATE VERY HIGH ENERGY ELECTRON BEAMS
Abstract
Background and Aims
In the process of establishing calorimetry as a primary standard for Very High Energy Electrons (VHEEs), measurements were performed in an ultra-high-dose-rate (UHDR) VHEE beam using the CLEAR facility at CERN. VHEEs with energies up-to 200 MeV could provide various benefits over standard clinical energy electron beams including increased conformity, deep-seated and complex tumour treatment as well as beam scanning and focusing.
Methods
The National Physical Laboratory graphite calorimeter, designed for Intensity Modulated Radiotherapy (IMRT), measured dose-to-graphite up-to approximately 5 Gy/pulse with dose-to-water calculated by application of a preliminary graphite-to-water conversion factor determined using the Geant4 Monte Carlo code. The CLEAR beamline allowed for investigation of both clinical dose-rate and UHDR regimes through tuning of the number of electron bunches per-pulse and the charge-per-bunch.
Results
As a result, the instantaneous dose-rate ranged between 5x106 Gy/s and 3.1x108 Gy/s whilst pulse widths ranged from 666 ps (1 bunch-per-pulse) to 133.2 ns (200 bunches-per-pulse). The dose-per-pulse ranging from 0.03 Gy/pulse to 5.26 Gy/pulse was found to increase linearly with increasing charge-per-pulse with R2=0.98 .
Conclusions
These calorimetry measurements allowed for absolute determination of ionisation chamber correction factors applicable to clinical dosimetry protocols. Moreover, a full uncertainty budget including calorimeter vacuum gap correction and perturbation factors is currently being developed such that the translation of UHDR VHEE beams to the clinical setting can be accelerated.
This project 18HLT04 UHDpulse has received funding from the EMPIR programme co-financed by the Participating States and from the European Union’s Horizon 2020 research and innovation programme.