Characterization of a MLIC Detector for QA in Scanned Proton and Carbon Ion Beams
- Vai, Alessandro Fondazione CNAO (Italian National Center for Oncological Hadronterapy), Pavia, Italy
- Mirandola, Alfredo Fondazione CNAO (Italian National Center for Oncological Hadronterapy), Pavia, Italy
- Magro, Giuseppe Fondazione CNAO (Italian National Center for Oncological Hadronterapy), Pavia, Italy
- Maestri, Davide Fondazione CNAO (Italian National Center for Oncological Hadronterapy), Pavia, Italy
- Mastella, Edoardo Fondazione CNAO (Italian National Center for Oncological Hadronterapy), Pavia, Italy
- Mairani, Andrea Heidelberg Ion-Beam Therapy Center, Heidelberg, Germany
- Molinelli, Silvia Fondazione CNAO (Italian National Center for Oncological Hadronterapy), Pavia, Italy
- Russo, Stefania Fondazione CNAO (Italian National Center for Oncological Hadronterapy), Pavia, Italy
- Togno, Michele Now at Center for Proton Therapy, Paul Scherrer Institut, Villigen, Switzerland
- Civita, Sara La Now at Mevion Medical System BV, Maastricht, Holland
- Ciocca, Mario Fondazione CNAO (Italian National Center for Oncological Hadronterapy), Pavia, Italy
- 2019-11-26
Published in:
- International Journal of Particle Therapy. - International Journal of Particle Therapy. - 2019, vol. 6, no. 2, p. 50-59
English
Abstract
Purpose:
Beam energy validation is a fundamental aspect of the routine quality assurance (QA) protocol of a particle therapy facility. A multilayer ionization chamber (MLIC) detector provides the optimal tradeoff between achieving accuracy in particle range determination and saving operational time in measurements and analysis procedures. We propose the characterization of a commercial MLIC as a suitable QA tool for a clinical environment with proton and carbon-ion scanning beams.
Materials and Methods:
Commercial MLIC Giraffe (IBA Dosimetry, Schwarzenbruck, Germany) was primarily evaluated in terms of short-term and long-term stability, linearity with dose, and dose-rate independence. Accuracy was tested by analyzing range of integrated depth-dose curves for a set of representative energies against reference acquisitions in water for proton and carbon ion beams; in addition, 2 modulated proton spread-out Bragg peaks were also measured. Possible methods to increase the native spatial resolution of the detector were also investigated.
Results:
Measurements showed a high repeatability: mean relative standard deviation was within 0.5% for all channels and both particle types. The long-term stability of the gain calibration showed discrepancies less than 1% at different times. The detector response was linear with dose (R2 > 0.99) and independent on the dose rate. Measurements of integrated depth-dose curve ranges revealed a mean deviation from reference measurements in water of 0.1 ± 0.3 mm for protons with a maximum difference of 0.4 mm and 0.2 ± 0.6 mm with maximum difference of 0.85 mm for carbon ion beams. For the 2 modulated proton spread-out Bragg peaks, measured differences in distal dose falloff were ≤0.5 mm against calculated values.
Conclusions:
The detector is stable, linearly responding with dose, precise, and easy to handle for QA beam energy checks of proton and carbon ion beams.
- Language
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- English
- Open access status
- gold
- Identifiers
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- DOI 10.14338/ijpt-19-00064.1
- ISSN 2331-5180
- Persistent URL
- https://sonar.ch/global/documents/159501
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