NMR antenna for an interstitial ultrasound applicator^*

¹ Laboratoire de RMN, UMR 5012, Université Claude Bernard Lyon 1 – CPE, 43 Bd. du 11 Novembre 1918, 69622 Villeurbanne Cedex, France
² Unité INSERM 556, 151 cours Albert Thomas, 69424 Lyon Cedex 03, France

Corresponding author: marguet@univ-lyon1.fr

Received: 15 November 2001
Revised: 26 March 2003
Accepted: 13 June 2003
Published online: 15 September 2003

Abstract

The aim of this work is to study and design a NMR micro antenna dedicated to ultrasound lesion monitoring by imaging. This micro-antenna will be associated with an oesophageal ultrasound applicator used for oesophagus tumour therapy to provide guidance and monitoring by magnetic resonance imaging (MRI). So, the micro-antenna design was guided by size and shape constraints due to endocavitary applications and adaptation to the ultrasound applicator. In this scope, a coil of N rectangular loops was built. In order to minimise size and offer the ability to perform in vivo adjustments, remote tuning and matching was performed. MRI investigations were carried out using two antennas: a volumic transmitter coil for excitation and this endoscopic receiver coil for signal capture. Lesion can be clearly seen on T2-weighted MR imaging. Lesion measurements on sagittal and axial slices gave a good correlation with lesion dimensions measured on sample.