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Lithium borate TLD for determining the backscatter factors for low‐energy x rays: Comparison with chamber‐based and Monte Carlo derived values
Author(s) -
Coudin Dany,
Marinello Ginette
Publication year - 1998
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 - 10.1118/1.598205
Subject(s) - monte carlo method , thermoluminescent dosimeter , dosimetry , ionization chamber , backscatter (email) , computational physics , boron , materials science , optics , physics , detector , ion , nuclear physics , nuclear medicine , mathematics , computer science , statistics , medicine , telecommunications , quantum mechanics , dosimeter , wireless , ionization
Recently, new backscatter factors for low‐energy x rays derived from Monte Carlo calculations have been recommended in the UK code of practice for kilovoltage dosimetry published by (IPEMB). As these data, presented as a function of half‐value layer, do not take account of the variation of the x‐ray spectra for a given HVL, we have undertaken an experimental study in order to determine BSF for the beam qualities provided by a Darpac 2000 therapy unit. A RTL detector such as Li 2B 4O 7: Cu and parallel‐plate ion chambers specially designed for low‐energy x‐ray dosimetry have been used. The results obtained show very good agreement between the TLD and the Monte Carlo calculations, confirming values obtained by other authors with lithium borate TLD. On the contrary, the results obtained with plane‐parallel ion chambers show discrepancies up to 9% that are discussed.