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M J Rossiter

Publications and source records attributed to M J Rossiter.

5 recordsLinked to original sources

Calibration of the NPL secondary standard radionuclide calibrator for 192Ir brachytherapy sources.

Safe and effective treatment with brachytherapy sources requires an accurate knowledge of the local tissue absorbed dose rate derived from the source reference air kerma rate. It is desirable that these air kerma rate measurements be traceable to national standards. The NPL has embarked on a programme that will enable the user to assay brachytherapy sources in a convenient manner prior to treatment. Calibration figures have been derived for the NPL secondary standard radionuclide calibrator for 192Ir brachytherapy sources manufactured by Amersham International plc. The calibration figures enable the user to accurately estimate the reference air kerma rate and activity of such sources by measuring the ionization chamber response. Calibration figures for other brachytherapy sources are also being derived.

Brachytherapy↗

The use of precision thermoluminescence dosimetry for intercomparison of absorbed dose.

A technique is described for making thermoluminescence measurements on phosphor powder with a relatively high degree of precision. Factors such as the rate of fading of TL response and extent of supralinearity for TLD-700 in the therapy-dose range have been measured in relation to its use for precise absorbed dose intercomparison studies in cobalt-60 beams. The results of such a trial intercomparison of six British radiotherapy centres are given, the performance of the TLD technique being matched against that of Fricke dosemeters. Factors involved in the extension of the technique to medium-energy X-rays are discussed including the possibility of determination of beam quality by employing TLD-700 and CaSO4: Dy 'in tandem'.

Cobalt Radioisotopes↗