Title: MRI Guided Liver Ablation
Funder: Department of Health (England)

Abstract: Background Hepatocellular carcinoma is the 5th most common malignancy. Its incidence and mortality have doubled over the past 20 years and continues to increase (1,2). Treatment involves ablative therapy (3,4) and would greatly benefit from MRI guidance, which is radiation dose-independent and can monitor tissue temperature (5,6). The main technical obstacles are image artefacts from liver motion due to breathing (7) and severely restricted access to the patient inside the conventional, cylindrical MRI magnet. Both of these will be addressed by the research. Previously described systems have relied on using open magnets, which are relatively uncommon. This proposal exploits prior experience with MR compatible robotic devices (8) and high quality localised MR receivers (9). Aims A MR compatible robotic system will be developed, which will have the ability to manipulate needles and devices inside the space of a conventional cylindrical magnet and to track the respiratory movements of tissue deep inside the body. Needle designs suitable for use within the magnet confines and equipped with appropriate fiducial locators and RF coils will be developed. Tracking will involve rapid imaging of fiducial markers, by using specially developed switchable RF coils that will be placed externally on the patient’s skin, as well as by rapid imaging of the diaphragm. Re-sequencing of previously obtained abdominal scans will be used to provide 3D navigation feedback in addition to scans performed during the procedure. Laser ablation will be the primary ablation method considered. Plan of Investigation The project will be conducted over 3 years as a close collaboration between Imperial College Engineering Departments (Mechanical, Electrical and Electronic) and Imperial College NHS Trust at St Mary’s Hospital. The main technical tasks involve the following developments: i) a robotic system ii) RF fiducial markers and tissue tracking iii) needles for ablation therapy iv) system integration The project is planned to involve limited patient trials in order to demonstrate the concepts. The major year 1 milestones will include design and demonstration of key technical concepts. Year 2 milestones will involve detailed design and manufacture of the main subsystems, while in year 3 it is planned to complete system integration, to conduct the proof of concept trials and evaluation. Potential Impact If successful, the project will lead to improved treatment of hepatocellular carcinoma (HCC) and diagnosis of focal liver disease. All liver disease is increasing rapidly (driven, in part, by the obesity epidemic, increasing prevalence of viral hepatitis and early-age alcohol consumption) and consequentially, HCC is increasing fast (1,2). Image guidance offers greater reliability of outcome in both therapy and diagnosis (10), and MRI avoids any X-ray dose issues for both patients and staff. Compatibility with conventional MRI magnets, which are continuously reducing in cost, will further facilitate adoption of the method. Improving the delivery and accuracy of the much less intrusive thermal therapy will result in a very direct patient benefit,


Research activity codes: 5.5 RADIOTHERAPY AND OTHER NON-INVASIVE THERAPIES
Health categories: CANCER AND NEOPLASMS