Two-dimensional real-time quality assurance dosimetry system using μ-Al2O3:C,Mg radioluminescence films

Luana De Freitas Nascimento, Dirk Verellen, Jo Goossens, Lara Struelens, Filip Vanhavere, Paul Lebans, Mark Akselrod

Research outputpeer-review


Background and purpose: There is a continual need for more accurate and effective dosimetric systems for quality assurance (QA) as radiotherapy evolves in complexity. The purpose of this project was to introduce a new system that minimally perturbs the main beam, while assessing its real time 2D dose-rate and field shapes. The system combined reusability, linear dose-rate response, and high spatial and time resolution in a single radiation detection technology that can be applied to surface dose estimation and QA. Materials and methods: We developed a 2D prototype system consisting of a camera, focusing lenses and short pass filter, placed on the head of a linear accelerator, facing an Al2O3:C,Mg radioluminescent film. To check the appropriateness of multi-leaf collimator, stability/reproducibility QA tests were prepared using the treatment planning system: including the routinely used alternating leaves, chair and pyramid checks. Results: The Al2O3:C,Mg film did not perturb the dose vs. depth dose curves determined with a point detector (-0.5% difference). Our results showed a dose-rate linear film response (R2 = 0.999), from 5 to 600 MU/min. Measured output factors agreed with reference data within ~1%, indicating a potential for small field dosimetry. Both chair and pyramid measured profiles were comparable with those obtained with the treatment planning system within 1%. The alternating leaves test showed an average discrepancy in the valleys of 14%. Conclusions: The prototype demonstrated promising results. It obviated the need for corrections regarding the relative position of the camera, confirming accurate dose-rate delivery and detection of radiation fields.
Original languageEnglish
Pages (from-to)26-32
Number of pages7
JournalPhysics and Imaging in Radiation Oncology
StatePublished - 1 Oct 2020
Event2020 - European Society for Radiotherapy and Oncology - Online
Duration: 28 Nov 20201 Dec 2020

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