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Well‐ionization chamber response relative to NIST air‐kerma strength standard for prostate brachytherapy seeds
Author(s) -
Mitch Michael G.,
Zimmerman Brian E.,
Lamperti Paul J.,
Seltzer Stephen M.,
Coursey Bert M.
Publication year - 2000
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.1290715
Subject(s) - kerma , ionization chamber , brachytherapy , dosimetry , ionization , nist , quality assurance , nuclear medicine , calibration , medical physics , environmental science , materials science , medicine , physics , radiation therapy , radiology , computer science , ion , external quality assessment , pathology , quantum mechanics , natural language processing
The response of well‐ionization chambers to the emissions of103 Pd and125 I radioactive seed sources used in prostate cancer brachytherapy has been measured. Calibration factors relating chamber response (current or dial setting) to measured air‐kerma strength have been determined for seeds from nine manufacturers, each with different designs. Variations in well‐ionization chamber response relative to measured air‐kerma strength have been observed because of differences in the emitted energy spectrum due to both the radionuclide support material ( 125 I seeds) and the mass ratio of103 Pd to102 Pd( 103 Pd seeds). Obtaining accurate results from quality assurance measurements using well‐ionization chambers at a therapy clinic requires knowledge of such differences in chamber response as a function of seed design.