Calibration of a scintillation dosemeter for beta rays using an extrapolation ionization chamber

Area of Science:

• Medical physics
• Radiation dosimetry
• Ophthalmology

Background:

• Accurate measurement of beta radiation dose is crucial for ophthalmic applications.
• Scintillation dosemeters offer potential advantages for in-vivo dosimetry but require precise calibration.
• Strontium-90/Yttrium-90 (90Sr/90Y) is a common radionuclide used in ophthalmic brachytherapy applicators.

Purpose of the Study:

• To calibrate a scintillation dosemeter for 90Sr/90Y beta rays emitted from ophthalmic applicators.
• To establish the accuracy and uncertainty of the calibration procedure.
• To assess the suitability of a calibrated ophthalmic applicator as a reference radiation source.

Main Methods:

• Calibration of a scintillation dosemeter using a 90Sr/90Y ophthalmic applicator.
• Utilized an extrapolation ionization chamber as the primary reference instrument.
• Performed measurements to determine the calibration factor and associated uncertainties.

Main Results:

• The calibration factor for the scintillation dosemeter closely matched the manufacturer's value, with a discrepancy of approximately 2%.
• The overall estimated uncertainty for the calibration was determined to be approximately 6% (2 standard deviations).
• Demonstrated the feasibility of using a calibrated beta-ray ophthalmic applicator as a stable reference source.

Conclusions:

• The calibration method provides a reliable means to determine the response of scintillation dosemeters for ophthalmic beta-ray applications.
• The established calibration procedure and uncertainty are suitable for clinical and laboratory use.
• A calibrated 90Sr/90Y ophthalmic applicator serves as a valuable reference standard for ongoing quality assurance and calibration.