In recent years, High-Intensity Focused Ultrasound (FUS) under guidance of magnetic resonance imaging (MRI) has become a frequently applied means for non-invasive tumour therapy, e.g. in the treatment of fibromyoma of uterus and of bone metastases. However, treating tumours in moving organs is still a great challenge due to several complexities.
Processes affecting the outcome of FUS therapy range from the movement of the target, the physiology of the organs down to the energy deposition in the tissue and the heat transfer within the body. For the treatment of abdominal organs such as the liver, also acoustic shielding of the target by the ribcage and the vicinity to risk structures have to be respected. To incorporate all these complexities into a reliable prediction that allows the physician to perform safe, effective and efficient ablation requires computer support.

In the FUSIMO project, a patient-specific model of the relevant processes involved in the MR-guided FUS (MRgFUS) therapy is developed and validated to simulate the outcome of the therapy.

The benefits for the physician will include:

• Assessing the feasibility of the intervention
• Predicting and optimizing the outcome
• Detecting potential risks and avoiding them
• Monitoring the progress and tracking deviations from the planned procedure

The overall model consists of several sub-models, which interact and describe aspects in a hierarchical manner:

• Abdominal organ model to simulate motion and the influence on ultrasound application. This model includes geometric structures of organs, muscles and bones relevant for the target region.
• Target organ/tumour model to capture organ/tumour physiology, and organ/tumour reaction to therapy
• Microscopic tissue model to simulate direct heat ablation, model energy distribution, tissue heating and cooling
• Model to evaluate first steps to simulate drug delivery, microbubble distribution and dynamics

This generic model is individualised to the patient under treatment. Therefore, means for extracting relevant parameters to describe the patient-individual model characteristics are developed. This comprises MR sequences to distinguish tissue classes and characteristics, as well as motion tracking and thermometry methods. The FUSIMO developments are combined into a software system, demonstrating the workflow of patient-specific planning and outcome predictions using imaging data.
A particular emphasis in FUSIMO is put on evaluation and validation of the model in phantoms, soft embalmed human cadaver and explanted animal organ models. To this end, interfacing to a product FUS system as well as motion-tracking hardware is developed. Therapy monitoring and outcome prediction will be compared to the physical lesion produced by FUS. Safety and workflow considerations are integrated in the project at every stage to allow smooth incorporation.
FUSIMO results will be applicable to abdominal FUS application to moving organs, as well as other treatment modalities such as radio frequency, laser or cryotherapy or other types of interventions based on high energy particles or fields in radiation therapy.

Policy Context

The project is funded under the EU's Seventh Framework Programme for Research and Technological Development (FP7-ICT-2009-6-270186).

The project consortium consists of:

• Fraunhofer MEVIS, Germany
• IMSaT University Dundee, Scotland
• Technische Universiteit Delf,  Nedtherlands
• Stiftelsen SINTEF, Norway
• Mediri GmbH, Germany
• IBSMM spol. s r. o, zech Republic
• Insightec Limited, Israel
• Universita Degli Studi Di Roma La Sapienza, Italy
• Computer Vision Laboratory,Swiss Federal Institute of Technology Zurich, Switzerland
• GE Medical Systems Israel Ltd., Israel
• Medis Foundation, MEDIS, Romania

Description of target users and groups

The FUSIMO results will be of research nature. However, the technologies and solutions developed have the potential to be translated into clinical practice. Thus, the target users of the results are medical device manufacturers, hospitals and medical centres and medical doctors, in particular surgeons and interventional radiologists.

Description of the way to implement the initiative

For the moment the project is at the research phase.

The work has been based on an extensive and systematic specification process, which incorporated requirements from clinical, workflow as well as technological perspectives. Based on these detailed specifications, an integrated software system has been designed and developed based on the MeVisLab software development platform (www.mevislab.de).

Technology solution

The FUSIMO software system is built in a completely modular manner, which allows independent development of the individual software components. The components interact with each other according to predefined interfaces (APIs). The core of the system is the multi-level model consisting of the components for motion modelling, physical modelling of the focus ultrasound in tissue, and the modelling of the biological effect of the focused ultrasound beam.

To incorporate patient-specific data, images from planning (magnetic resonance images, MRI) and intervention (ultrasound or MRI) are fed into the model components. The interplay between the data used and the models developed demanded very close cooperation between the different groups. This was achieved by the extensive specification process and an ongoing effort of regular communication and coordination among the groups.

The system itself has been carefully developed in an iterative design and assessment process. Dedicated requirements and workflow workshops were conducted. Together with clinical users, the system was evaluated as a tool supporting the workflow of planning and outcome prediction before an intervention.

In parallel to the developments of the models and the software demonstrator, work on the validation of the models and the system is being conducted. This encompasses developments in the fields of imaging (MR, US) and of the robotically assisted placement of the FUS transducer to ensure accurate transfer of the planned position into the intervention situation, as well as real-time control of the FUS hardware components. Based on these validation prerequisites, extensive validation efforts of all aspects of the model and the integrated system are being conducted in the final of the project. The FUS transducer itself is a proprietary technology of InSightec, which is also a project participant. Although a number of technologies in the project have been developed using proprietary systems, the technologies are transferrable to other systems, as well.

Main results, benefits and impacts

The expected outcome of the FUSIMO project is a demonstrator-software that incorporates validated multi-level models for FUS application in moving organs. This software demonstrator shall provide a proof-of-concept for supporting the physician in the patient specific planning a FUS procedure in moving abdominal organs and therefore it shall facilitate the use of MR-guided FUS. In fact, the results obtained in FUSIMO have the potential to show that FUS in the abdomen can be performed safely and effectively using image guided software technology. Thus, FUSIMO is a major step in making FUS treatment in the abdomen a competitive alternative to the surgical gold standard.

FUSIMO’s patient specific models can be translated to other organs and different types of tumour treatment. In principle all thermal therapies like radiofrequency- and laser-ablation, as well as targeted drug delivery and radiotherapy applications can benefit from the organ- and motion-models created in FUSIMO.

The long-term impact of FUSIMO lies in improving the treatment of cancer and metastases in a variety of organs and for a wide range of patients. This will contribute to substantially reducing the estimated 1.7 million deaths in Europe each year. The reduced side effects (compared to conventional surgery, systemic chemotherapy and radiation therapy) of the MR guided focused ultrasound surgery and targeted chemotherapeutic drug delivery will lead to a higher quality treatment of the patients at lower financial demand for health insurance and social welfare.

Track record of sharing

Scientific publications as well as information to the general public are the primary means of sharing the results. The FUSIMO project has made tremendous efforts from the beginning of the project to inform both scientific community as well as specific interest groups about the progress and the results.

FUSIMO presentations have been held at various noted conferences in the field (ECR, ISTU, STM, SMIT, CIRSE, MICCAI, VPH, EAES, etc.) and several scientific articles have been published or submitted.

Lessons learnt

1. Using patient-specific modelling for planning of FUS (focused ultrasound) interventions is feasible and can be made available to clinical users in an integrated software system. This, however, is ongoing work and the accuracy of the simulation is currently under investigation in the validation efforts.
2. There is a tremendous interest in the general public and the scientific community in non-invasive surgical technologies and the related potential benefits for patients and healthcare systems. This interest can and should be used to raise awareness of the project efforts, the research funding of the EU in these efforts and of the potential to market these technologies in the near future.
3. A collaborative effort of this size and in particular of different groups requires a methodical project coordination and the explicit commitment to cooperation from all project partners.