1: Magn Reson Med. 2009 Feb 27;61(5):1225-1231. [Epub ahead of print]

Evaluation of the dose distribution gradient in the close vicinity of
brachytherapy seeds using electron paramagnetic resonance imaging.

Vanea ES, Levêque P, Abboud F, Bol A, Denis JM, Kolbun N, Vynckier S, Gallez B.

Biomedical Magnetic Resonance Unit, Université catholique de Louvain, Brussels,
Belgium.

Electron paramagnetic resonance (EPR) spectroscopy has been successfully employed
to determine radiation dose using alanine. The EPR signal intensity reflects the 
number of stable free radicals produced, and provides a quantitative measurement 
of the absorbed dose. The aim of the present study was to explore whether this
principle can be extended to provide information on spatial dose distribution
using EPR imaging (EPRI). Lithium formate was selected because irradiation
induces a single EPR line, a characteristic that is particularly convenient for
imaging purposes. (125)I-brachytherapy seeds were inserted in tablets made of
lithium formate. Images were acquired at 1.1 GHz. Monte Carlo (MC) calculations
were used for comparison. The dose gradient can be determined using
two-dimensional (2D) EPR images. Quantitative data correlated with the dose
estimated by the MC simulations, although differences were observed. This study
provides a first proof-of-concept that EPRI can be used to estimate the gradient 
dose distribution in phantoms after irradiation. Magn Reson Med, 2009. (c) 2009
Wiley-Liss, Inc.


PMID: 19253364 [PubMed - as supplied by publisher]

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