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Measurement of the restricted dose mean LET outside the primary beam of a /sup 60/Co radiotherapy unit

Journal Article · · Radiat. Res.; (United States)
DOI:https://doi.org/10.2307/3576891· OSTI ID:6788853
A recently developed method for the direct measurement of the restricted dose mean LET (cutoff energy = 500 eV) of an unspecified photon or electron radiation field with the high-pressure ionization chamber has been utilized to investigate the variation of this radiobiologically important parameter outside the primary beam of a clinical /sup 60/Co unit. A small high-pressure tissue-equivalent ionization chamber was used, and its characteristics and experimental considerations for the present investigation are reported. Measurement of the restricted dose mean LET at the examined points outside the primary /sup 60/Co beam showed an increase of 50% with respect to the restricted dose mean LET of the uncollimated /sup 60/Co beam. No significant variation was noted with off-central axis distance, field size, wedge filter, or depth below Perspex slabs. Dose rates at the points of measurement outside the primary /sup 60/Co beam were 1-5% of the dose rate in the primary beam.
Research Organization:
Metaxa Memorial, Piraeus, Greece
OSTI ID:
6788853
Journal Information:
Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 1; ISSN RAREA
Country of Publication:
United States
Language:
English