Multi-layer Ionization Chamber for Quality Assurance and Stopping Power Measurements
The Center for Proton Therapy of the Paul Scherrer Institute has a long history of technical innovation and development in the field of proton therapy and related quality assurance (QA). The second proton pencil beam scanning gantry built at the CPT, Gantry 2, is a state-of-the-art system. The unique integration of QA equipment and detectors within the control system of the gantry allows for fast and detailed measurements. Here we present our latest developments in detection systems, their performance for QA and research capabilities in comparison with their commercial equivalent.
The QA equipment developed for proton range measurement at Gantry 2 consists of a multi-layer ionization chamber (MLIC). The extensive integration of our detectors with the control system allows fast spot-based measurement. Including the energy change, we can achieve a proton range evaluation within 125 ms. Consequently, our device can measure the proton range alteration caused by material samples for hundreds of energies within less than a minute. This allows us to measure the stopping power of compound material within minutes. We compare the stopping power evaluation using the MLIC against three other techniques.
The results show the strong points of the equipment developed in-house, such as the consistency, the reliability and the innovation possibilities.
KeywordsProton therapy Ionization chamber Quality assurance
- 2.Fanny, V.: Characterizing and validating DECT rho/Z algorithm for proton therapy application: an experimental study. Semester project, ETHZ Zurich and EPFL Lausanne (2017)Google Scholar
- 3.La Rosa, A., Donetti, M., Borri, M., Rivero, F., Attili, A., Bourhaleb, F., Cirio, R., Garella, M., Giordanengo, S., Givehchi, N., et al.: Characterization of a front-end electronics for the monitoring and control of hadrontherapy beams. Nucl. Instrum. Methods Phys. Res., Sect. A 586(2), 270–275 (2008)ADSCrossRefGoogle Scholar
- 5.Pedroni, E., Bearpark, R., Böhringer, T., Coray, A., Duppich, J., Forss, J., George, D., Grossmann, M., Goitein, G., Hilbes, C., Jermann, M., Lin, S., Lomax, A., Negrazus, M., Schippers, M., Kotle, G.: The PSI Gantry 2: a second generation proton scanning gantry. Z. Med. Phys. 14(1), 25–34 (2004)CrossRefGoogle Scholar
- 7.Schippers, J.M., Dölling, R., Duppich, J., Goitein, G., Jermann, M., Mezger, A., Pedroni, E., Reist, H.W., Vrankovic, V.: The SC cyclotron and beam lines of PSIs new protontherapy facility PROSCAN. Nucl. Instr. Meth. Phys. B 261(1–2), 773–776 (2007). http://www.sciencedirect.com/science/article/pii/S0168583X07008129ADSCrossRefGoogle Scholar