Islam El Gamal, David Wilkins
Thursday, October 18, 2012

Time:   3:30 - 5:00 pm – October 18, 2012

Location:   West Foustanellas Auditorium (H-2366) – 2nd floor – The University of Ottawa Heart Institute, 40 Ruskin Street (map)


1. “Feasibility study of the determination of absorbed dose to water using a Fricke based system”

Islam El Gamal – Carleton University

Abstract: By measuring the dose to water directly a metrology standard, independent of air kerma, can be developed to make the basis of HDR brachytherapy dosimetry consistent with current dosimetry methods for external radiation beams. The Fricke dosimeter system, a liquid chemical dosimeter, provides a means of measuring the absorbed dose rate to water directly by measuring the radiation-induced change in optical absorption of the Fricke solution. In an attempt to measure the absorbed dose to water directly for a 192Ir HDR brachytherapy source a ring shaped Fricke holder was constructed from PMMA. Benchmark measurements conducted in a 60Co beam yielded a standard uncertainty in the absorption reading of 0.16 %, comparable with previous results in the literature. Measurements of the standard uncertainty of the control (un-irradiated) solution using the holder yielded 0.13 %, indicating good process control and minimal contamination from the holder itself. Irradiations with a 17 GBq source, in a water phantom, gave a standard uncertainty of approximately 0.29 %, indicating that the target uncertainty of less than 1% for the measurement of absorbed dose to water using a Fricke-based primary standard is achievable. This would be comparable with water calorimeter standards currently being developed.

2. “Radiation Safety Then and Now”

David Wilkins – The Ottawa Hospital Cancer Centre

Abstract: The practice of radiation safety in cancer centers has evolved considerably over the years, from a technical discipline to an organizational approach incorporating elements of quality management with a focus on patient safety.  This talk will discuss that evolution and its impact on staff doses, and will describe some recent changes to regulations which have affected the approach to radiation safety in cancer centers.