The determination of dose characteristics of ruthenium ophthalmic applicators using radiochromic film

G. Taccini, F. Cavagnetto, G. Coscia, S. Garelli, A. Pilot

Research output: Contribution to journalArticlepeer-review

Abstract

Ruthenium ophthalmic applicators are energetic beta ray sources, supplied in several shapes and dimensions, and used in intraocular tumor therapy. Because of their small dimensions, the determination of dosimetric characteristics represents a technical challenge. We developed a semiautomatic method to define surface dose, dose distribution, and percentage depth dose of such applicators using radiochromic dosimetric media. These detectors consist of a thin (7 μm) radiation sensitive layer on polyester base (100 μm total thickness) changing color as a function of radiation exposure. Transmission images of exposed films were then grabbed with a TV-digitizer system to obtain a gray-level image from which dosimetric characteristics such as isodose distribution, dose values, and homogeneity of nuclide distribution were derived. Good agreement between experimental results and Monte Carlo simulation performed using the GEANT 3 code, appear to be a confirmation of the validity of the method. Moreover while manufacturer specifications of absolute and relative dose rates present a standard deviation error of ±30% on dose rate and ±6% on accuracy of relative dose values, the proposed method reduces the errors to ± 10% and ±4%, respectively.

Original languageEnglish
Pages (from-to)2034-2037
Number of pages4
JournalMedical Physics
Volume24
Issue number12
DOIs
Publication statusPublished - Dec 1997

Keywords

  • Dosimetry
  • Monte Carlo simulation
  • Ophthalmic applicators
  • Radiochromic film

ASJC Scopus subject areas

  • Biophysics

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