Ultrasound applicator for destruction of oesophagus tumours: first animals trials

Oesophagus cancer remains frequent with a bad prognosis despite the good short term results obtained by the association of radiochemotherapy and surgery. So, new curative and palliative treatments must be proposed. Efforts are currently undertaken to improve palliative therapy or even to achieve local tumour control by use of physical agents. It was demonstrated that High Intense Ultrasound (HIU) may induce rapid and complete coagulation necrosis with a well define geometry. Using this technique a 10 MHz transoesophageal applicator with external water cooling was developed. The active part is an air-backed plane rotating transducer to obtain sector-based or cylindrical coagulation necrosis. This applicator slides on a guide wire previously introduced in the oesophagus. The firing sequence consists to link up several shots every 10 seconds. The applicator operating at 14 W/cm/sup 2/ for 10 seconds was rotated through an angle of 18/spl deg/ after each shot. Results obtained on five healthy pig oesophagus shown that it was possible to induce homogeneous lesions without risk of perforation or lesion on surrounding tissue destruction. These promising results indicate that this ultrasound system may represent an effective tool for the treatment of oesophageal tumours in humans. An Independent Ethics Committee has recently approved an ongoing pilot clinical trial of this applicator.