Miniaturized scintillator dosimeter for small field radiation therapy
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2021-05-11 |
| Journal | Physics in Medicine and Biology |
| Authors | Mathieu Gonod, Carlos Chacon Avila, Miguel Angel SuĂĄrez, Julien Crouzilles, Samir Laskri |
| Institutions | Centre Georges François Leclerc, Centre National de la Recherche Scientifique |
| Citations | 17 |
Abstract
Section titled âAbstractâAbstract The concept of a miniaturized inorganic scintillator detector is demonstrated in the analysis of the small static photon fields used in external radiation therapy. Such a detector is constituted by a 0.25 mm diameter and 0.48 mm long inorganic scintillating cell (1.6 Ă 10 â5 cm 3 detection volume) efficiently coupled to a narrow 125 Îź m diameter silica optical fiber using a tiny photonic interface (an optical antenna). The response of our miniaturized scintillator detector (MSD) under 6 MV bremsstrahlung beam of various sizes (from 1 Ă 1 cm 2 to 4 Ă 4 cm 2 ) is compared to that of two high resolution reference probes, namely, a micro-diamond detector and a dedicated silicon diode. The spurious Cerenkov signal transmitted through our bare detector is rejected with a basic spectral filtering. The MSD shows a linear response regarding the dose, a repeatability within 0.1% and a radial directional dependence of 0.36% (standard deviations). Beam profiling at 5 cm depth with the MSD and the micro-diamond detector shows a mismatch in the measurement of the full widths at 80% and 50% of the maximum which does not exceed 0.25 mm. The same difference range is found between the micro-diamond detector and a silicon diode. The deviation of the percentage depth dose between the MSD and micro-diamond detector remains below 2.3% within the first fifteen centimeters of the decay region for field sizes of 1 Ă 1 cm 2 , 2 Ă 2 cm 2 and 3 Ă 3 cm 2 (0.76% between the silicon diode and the micro-diamond in the same field range). The 2D dose mapping of a 0.6 Ă 0.6 cm 2 photon field evidences the strong 3D character of the radiation-matter interaction in small photon field regime. From a beam-probe convolution theory, we predict that our probe overestimates the beam width by 0.06%, making our detector a right compromise between high resolution, compactness, flexibility and ease of use. The MSD overcomes problem of volume averaging, stem effects, and despite its water non-equivalence it is expected to minimize electron fluence perturbation due to its extreme compactness. Such a detector thus has the potential to become a valuable dose verification tool in small field radiation therapy, and by extension in Brachytherapy, FLASH-radiotherapy and microbeam radiation therapy.
Tech Support
Section titled âTech SupportâOriginal Source
Section titled âOriginal SourceâReferences
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