eprintid: 1570219 rev_number: 42 eprint_status: archive userid: 608 dir: disk0/01/57/02/19 datestamp: 2017-08-16 11:57:57 lastmod: 2021-12-05 00:25:59 status_changed: 2017-08-16 11:57:57 type: article metadata_visibility: show creators_name: Almurayshid, M creators_name: Helo, Y creators_name: Kacperek, A creators_name: Griffiths, J creators_name: Hebden, J creators_name: Gibson, A title: Quality assurance in proton beam therapy using a plastic scintillator and a commercially available digital camera ispublished: pub divisions: UCL divisions: B04 divisions: C05 divisions: F42 keywords: Proton therapy, quality assurance, radiotherapy note: This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine abstract: PURPOSE: In this article, we evaluate a plastic scintillation detector system for quality assurance in proton therapy using a BC-408 plastic scintillator, a commercial camera, and a computer. METHODS: The basic characteristics of the system were assessed in a series of proton irradiations. The reproducibility and response to changes of dose, dose-rate, and proton energy were determined. Photographs of the scintillation light distributions were acquired, and compared with Geant4 Monte Carlo simulations and with depth-dose curves measured with an ionization chamber. A quenching effect was observed at the Bragg peak of the 60 MeV proton beam where less light was produced than expected. We developed an approach using Birks equation to correct for this quenching. We simulated the linear energy transfer (LET) as a function of depth in Geant4 and found Birks constant by comparing the calculated LET and measured scintillation light distribution. We then used the derived value of Birks constant to correct the measured scintillation light distribution for quenching using Geant4. RESULTS: The corrected light output from the scintillator increased linearly with dose. The system is stable and offers short-term reproducibility to within 0.80%. No dose rate dependency was observed in this work. CONCLUSIONS: This approach offers an effective way to correct for quenching, and could provide a method for rapid, convenient, routine quality assurance for clinical proton beams. Furthermore, the system has the advantage of providing 2D visualization of individual radiation fields, with potential application for quality assurance of complex, time-varying fields. date: 2017-09 date_type: published official_url: http://dx.doi.org/10.1002/acm2.12143 oa_status: green full_text_type: pub language: eng primo: open primo_central: open_green article_type_text: Journal Article verified: verified_manual elements_id: 1413008 doi: 10.1002/acm2.12143 lyricists_name: Gibson, Adam lyricists_name: Griffiths, Jennifer lyricists_name: Hebden, Jeremy lyricists_id: APGIB90 lyricists_id: JAGRI83 lyricists_id: JCHEB81 actors_name: Bracey, Alan actors_id: ABBRA90 actors_role: owner full_text_status: public publication: Journal of Applied Clinical Medical Physics volume: 18 number: 5 pagerange: 210-219 event_location: United States issn: 1526-9914 citation: Almurayshid, M; Helo, Y; Kacperek, A; Griffiths, J; Hebden, J; Gibson, A; (2017) Quality assurance in proton beam therapy using a plastic scintillator and a commercially available digital camera. Journal of Applied Clinical Medical Physics , 18 (5) pp. 210-219. 10.1002/acm2.12143 <https://doi.org/10.1002/acm2.12143>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/1570219/1/Almurayshid_et_al-2017-Journal_of_Applied_Clinical_Medical_Physics.pdf