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Dosimetric characterization of a silicon diode detector in cyclotron-based passively scattered and synchrotron-based scanning clinical proton beams
- Source :
- Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 891:125-132
- Publication Year :
- 2018
- Publisher :
- Elsevier BV, 2018.
-
Abstract
- A PR60020 silicon diode detector (PTW-Freiburg, Germany) was tested at INFN-LNS cyclotron on the scattered proton beamline (62 MeV) dedicated to ocular treatments. For the first time, the detector was also characterized in scanning proton beams accelerated by the CNAO synchrotron (63–229 MeV). The characteristics of the diode detector for proton beam dosimetry were investigated in terms of response stability, linearity with dose and dependence on dose rate and beam quality. Depth–ionization curves were measured for unmodulated, unmodulated range-shifted beams and spread-out Bragg peaks (SOBP); results were compared with reference ones obtained with an ionization chamber. Output Factors of narrow beams used in ocular proton-therapy were measured and compared to those achieved using EBT3 films. The PR60020 diode showed a reproducible response as for short-term precision (0.5%) and medium-term stability (1.5%). Dose and dose rate dependence measurements showed deviations from linearity within ± 1%. The calibration factor (Gy/nC) was constant within ± 1% over the range of proton beam qualities of ocular proton-therapy, while 1.4% maximum variation of diode sensitivity among CNAO energies was found. Output factors agreed with reference ones within 2% down to 5 mm collimator diameter. Bragg peak curves closely matched those acquired with ionization chamber, relative differences being lower than 3% in peak-to-plateau ratios. Very good results were also found for SOBP dose measurements as in scattered and scanned proton beams. In conclusion, diode detector appeared suitable for relative dosimetry and absorbed dose determination in passively scattered and scanning clinical proton beams, particularly for very small fields used for ocular treatments.
- Subjects :
- Physics
Nuclear and High Energy Physics
Physics::Instrumentation and Detectors
business.industry
Physics::Medical Physics
Detector
Sobp
Dose profile
Bragg peak
Synchrotron
030218 nuclear medicine & medical imaging
law.invention
03 medical and health sciences
0302 clinical medicine
Optics
law
030220 oncology & carcinogenesis
Absorbed dose
Ionization chamber
Physics::Accelerator Physics
Dosimetry
business
Instrumentation
Subjects
Details
- ISSN :
- 01689002
- Volume :
- 891
- Database :
- OpenAIRE
- Journal :
- Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
- Accession number :
- edsair.doi...........95869b028117e59536b3ddbb52ea5e0c