WE-AB-BRB-02: Development of a Micro-Sized Dosimeter for Real-Time Dose Monitoring and Small Field Dosimetry

Journal Article · Mon Jun 15 00:00:00 EDT 2015 · Medical Physics

DOI:https://doi.org/10.1118/1.4925843· OSTI ID:22570079

Volotskova, O; Jenkins, C; Fahimian, B; Xing, L ^[1]

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1. Stanford University, Stanford, CA (United States)

Purpose: To investigate a miniature optical dosimeter for real-time, high-resolution dosimetry, and explore its potential applications for in vivo measurements and small field dosimetry. Methods: A micro-sized hemispherical (400 µm radius) scintillating detector was constructed from lanthanide activated phosphors doped with Europium (GOS:Eu) and encapsulated in a 17 gauge plastic catheter. A photon counting PMT and CCD-chip spectrometer were used to detect signals emitted from the detector. A single band-passing spectral approach (630nm) was implemented to discriminate the micro-phosphor optical signal from background signals (Cerenkov radiation) in the optical fiber. To test real-time monitoring capabilities, a 3D-printed phantom was used to detect an 192Ir HDR brachytherapy source at locations ranging from 1 to 4 cm radially and 12 cm along the travel axis of the HDR wire. To test the application of the micro-sized detector for small field dosimetry, the linearity of detector was characterized through irradiation of 6MV photon beam at dose-rates ranging from 100 to 600 MU, and the effect of field size was characterized through detections of beams ranging from 30×30 to 1×1 cm2 size. Results: With a 1 second integration time for the spectrometer, the recorded measurements indicated that the micro-sized detector allowed accurate detection of source position at distances of up to 6 cm along the axis of travel in water. EB measurements showed that the detected signal was linearly correlated with dose rate (R{sup 2} = 0.99). The crossbeam profile was determined with a step size of ∼500 µm. Conclusion: Miniaturization of optical dosimeters is shown to be possible through the construction of lanthanide activated doped phosphors detectors. The small size of the detector makes it amenable to a variety of applications, including real-time dose delivery verification during HDR brachytherapy and EB beam calibrations in small fields.

• OSTI ID: 22570079
• Journal Information: Medical Physics, Vol. 42, Issue 6; Other Information: (c) 2015 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-2405
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
61 RADIATION PROTECTION AND DOSIMETRY
BRACHYTHERAPY
CALIBRATION
CHARGE-COUPLED DEVICES
CHERENKOV RADIATION
DOPED MATERIALS
DOSE RATES
DOSEMETERS
DOSIMETRY
EUROPIUM
IN VIVO
IRIDIUM 192
IRRADIATION
OPTICAL FIBERS
PHANTOMS
PHOSPHORS
PHOTON BEAMS
PLASTICS
RADIATION DOSES
SPECTROMETERS