Measurement of radiation dose distributions by nuclear magnetic resonance (NMR) imaging

Abstract

A method is described for determining the spatial distribution of radiation dose in a tissue-equivalent phantom using nuclear magnetic resonance imaging. The conversion of ferrous ions to ferric by ionising radiation alters the magnetic moment and electron spin relaxation times of the metal ion. The spin relaxation times (T₁ and T₂) of the hydrogen nuclei in an aqueous solution of a ferrous salt are consequently reduced substantially. These changes in T₁ and T₂ can be measured using standard NMR techniques. The same conversion is used in conventional Fricke dosimetry, which can be used to calibrate the technique.