Dosimetry of Beta-Ray Opthalmic Applicators: Comparison of Different Measurement Methods

Published

October 16, 2008

Author(s)

Christopher G. Soares, S Vynckier, H Jarvinen, W G. Cross, J Hokkanen, P Sipila, D Fluhs, B Schaeken, F A. Mourtada, G A. Bass, T T. Williams

Abstract

An international intercomparison of the dosimetry of three beta particle emitting ophthalmic applicators was performed, which involved measurements with radiochromic film, thermoluminescence dosimeters (TLDs), alanine pellets, plastic scintillators, an extrapolation ionization chamber, a small fixed-volume ionization chamber, a diode detector and a diamond detector. The sources studied were planar applicators of ⁹⁰Sy-⁹⁰Y and ¹⁰⁶Ru-¹⁰⁶Rh, and a concave applicator of ¹⁰⁶Ru-¹⁰⁶Rh. Comparisons were made of absolute dosimetry determined at 1 mm from the source surface in water or water-equivalent plastic, and relative dosimetry along and perpendicular to the source axes. The results of the intercomparison indicate that the various methods yield consistent absolute dosimetry results at the level of 10-14% (one standard deviation) depending on the source. For relative dosimetry along the source axis at depths of 5 mm or less, the agreement was 3-9% (one standard deviation) depending on the source and the depth. Crucial to the proper interpretation of the measurement results is an accurate knowledge of the detector geometry, i.e., sensitive volume and amount of insensitive covering material. From the results of these measurements, functions which describe the relative dose rate along and perpendicular to the source axes are suggested.

Citation

Medical Physics

Pub Type

Journals

Keywords

¹⁰⁶Ru, ⁹⁰Sr, beta dosimetry, beta particles dosimetry, intercomparison ophthalmic applictors

Citation

Soares, C. , Vynckier, S. , Jarvinen, H. , Cross, W. , Hokkanen, J. , Sipila, P. , Fluhs, D. , Schaeken, B. , Mourtada, F. , Bass, G. and Williams, T. (2008), Dosimetry of Beta-Ray Opthalmic Applicators: Comparison of Different Measurement Methods, Medical Physics (Accessed April 24, 2024)