Radiofrequency ablation of liver tumors

© Photo Fraunhofer FIT

Evolution of the tissue temperature distribution on a slice through the liver geometry at 50s, 100s, and 600s respectively. The temperature distribution in the tissue is a function of the power input magnitude and distribution, the vessel cooling, the tissue and blood material properties and the tissue perfusion.

Radiofrequency ablation is a minimally invasive way to treat cancer without open surgery, by placing a needle inside the malignancy and destroying it through intensive heating. Whilst there are numerous advantages to this approach, it is not widely used for treatment as the intervention is hard to plan and it is almost impossible to monitor or assess. The major problem with this treatment currently is the recurrence of cancer. A successful intervention planning system would reduce the number of resections of malignant tumors in liver.

One current restriction towards the development of a patient-specific planning tool is the limited understanding of processes during tissue heating and ultimately tissue death. EU project IMPPACT (Image-based Multi-scale Physiological Planning for Ablation Cancer Treatment) aims to generate new insight into physiological processes and biochemical reactions in the context of tissue heating. Computer modeling and simulation will predict the radiofrequency ablation process and results will be cross compared to pre-clinical experiments followed by ongoing clinical treatment to ensure validity in the model. This extensive validation together with a user-centered software design approach will guarantee suitability of the solution for clinical practice.

One of the most advanced features of the project is the combination of two modeling approaches on the microscopic and macroscopic levels for generation of the patient-specific physiological model. This will provide surgeons with a patient specific planning system that could be run on standard PC as used in hospitals taking only hours for the computation of the optimized ablation protocol. In the future it is hoped that radiologists will be able to use the model simulations to predict the intervention results while testing a variety of alternative approaches before taking a final decision on the best intervention plan.

Training on the planning system is an important outcome of the project as statistical survival rates very much depend on the experience of the surgeon. IMPPACT hopes to create an augmented reality training simulator which will teach young surgeons about optimal Radiofrequency Ablation Treatment. The planning system will assist the radiologist in finding the optimal needle positions and will be able to predict intervention results.

IMPPACT hopes that this will become the treatment of choice for malignant liver tumors, with a specific focus on hepactic cellular carcinomas and liver metastases.