Design and Development of a Novel Endoscopic Microwave Ablation Device for the Treatment of Pancreatic Tumours

: - From Ideation to Human Use -

Abstract

This research is focused on the ideation, design, development, initial manufacture, and first human use of a new and novel microwave antenna and deployment system. The antenna delivers focussed microwave energy in the super high frequency region of the electromagnetic spectrum at a spot frequency of 5.8GHz to treat cancerous tumours under localised endoscopic ultrasound imaging.

The outer diameter of the antenna was required to be less than 1mm, and length 40mm. The antenna is in the form of a needle. It was necessary for the device to be flexible enough to be inserted into the instrument channel of an endoscopic ultrasound scope, but at the same time rigid enough to enable insertion through intermediate structures, such as the stomach wall and into the target tumour. The design of the antenna required extensive electromagnetic field simulation to optimise the shape of the power density profile using representative tissue models to ensure that the zone of ablation met the clinical requirements.

Due to the limitation on antenna size, system losses and the required shape of ablation, the design of the needle antenna structure was challenging, and it was found that it was necessary to deliver the microwave energy as pulses of energy, rather than continuous wave delivery. Pulsing the energy provided greater control over the temperature of the shaft of the needle antenna. This challenge was coupled with the essential requirement that all materials used were biocompatible and that the structure was robust enough to be introduced into a tumour within the human body, without the risk of mechanical failure.

This work also involved a comparison between microwave and radiofrequency energy delivery using in vivo and ex vivo tissue models, which led to the discovery of a correction factor between the width and length measurements of the ablated tissue taken from the ultrasound image and the width and length measurements from the excised tissue.

The device has gained both CE and FDA approval for usage in Europe and the United States of America and has been used to successfully treat seven patients with pancreatic lesions.

Date of Award	30 Jan 2024
Original language	English
Awarding Institution	Bangor University
Supervisor	Chris Hancock (Supervisor) & Iestyn Pierce (Supervisor)