New MRI-guided Focused Ultrasound Surgical system accommodates organ motion
Magnetic Resonance guided Focused Ultrasound Surgery (MRgFUS) is a non-invasive therapy that combines imaging, to visualise diseased tissue, with the use of ultrasonic waves. This powerful combination can be used to treat a range of tissue-related disorders (e.g. tumours or metastases). However, the technique proves problematic when used for the treatment of abdominal organs, due to breathing induced movement and the physical barrier of the rib cage. To meet this challenge, the EU-supported TRANS-FUSIMO project developed a MRgFUS surgical prototype which uses motion detection and compensation algorithms to give clinicians real-time positional control for treatment. Preclinical testing demonstrated that the system is capable of creating a thermal lesion (i.e. a small amount of thermally destroyed tissue) in a target structure that moves under respiratory motion. Once human clinical trials have been successfully conducted, these results increase the potential of MRgFUS to become a new routine therapy for liver cancer. An integrated real-time surgical system The TRANS-FUSIMO prototype is designed to treat patients using one software tool that controls the whole procedure by connecting to the necessary off-the-shelf hardware, such as the MRI for monitoring the procedure or the FUS device that beams the acoustic energy to the body. MRgFUS works by focusing a beam of high energy ultrasound waves from outside the body into the target structure (e.g. a cancerous tumour). As this structure moves while the patient breathes, the ultrasonic beam needs to be constantly reshaped and refocused. The TRANS-FUSIMO solution compensates for breathing in real-time by using live patient data to anticipate the target structure’s position and so electronically adapt the focal spot. It is then possible to fix on, and thermally destroy, the tumour cells. Building the technology required advanced software and architecture development to enable the real-time algorithm data feeds. “Since treating a small portion of the target structure, known as sonication, only lasts from a few seconds up to a minute, all computations have to be performed in real-time,” says Prof. Tobias Preusser, the project’s scientific coordinator. “For the first time, the challenge of real-time focus adjustments to target moving organs has been achieved, using off-the-shelf MRI and FUS hardware.” The resulting prototype was then tested ex-vivo (outside of a living organism), and the team used gel phantoms to successfully validate the safety and efficiency of the procedure. Non-invasive benefits Focused Ultrasound Surgery (FUS) has made it possible to destroy diseased tissues inside the body without a surgical incision or the insertion of instruments. This non-invasive technology has the potential to reduce side-effects and hospitalisation time for patients. Additionally, patients who have not been eligible for conventional therapy due to their general health condition, may be eligible for this kind of treatment. It is already in clinical use for the treatment of, among others, uterine fibroids, bone metastases, and prostate cancer. Currently, the technology is still undergoing the necessary preclinical investigation before moving to clinical tests, in anticipation of a potential market launch within 5 to 10 years to be targeted at vendors of FUS devices or MR imaging devices. “The TRANS-FUSIMO prototype system also includes components that can be integrated into non-FUS systems. For example, the real-time motion detection and compensation algorithms have great potential for image-guided procedures like interstitial thermal ablation, radiation therapy, imaging under motion, etc.”, adds Prof Mevis.
Keywords
TRANS-FUSIMO, cancer, liver, respiratory, non-invasive, Focused Ultrasound Surgery, Magnetic Resonance, tumour, ultrasonic, tissue, algorithm
