By focusing ultrasound waves on a target tissue located deep inside the body, local hyperthermia (approx. 42 ˚C) or to thermally ablation of tissue (T>55 ˚C) can be induced without affecting the surrounding tissue. Depending on the exact ultrasound pulses, mechanical destruction of the target tissue is also possible (histotripsy). Though the biological effects of high intensity focused ultrasound (HIFU) have been known and studied for almost a century, clinical use only recently become feasible, mainly through the combination of HIFU with either diagnostic ultrasound (US-HIFU) or magnetic resonance imaging (MR-HIFU) for image guidance. Image guidance provides therapy planning, but also provides (temperature) feedback during therapy to control the sonication with respect to reaching the treatment goal. Today, several HIFU applications are in clinical use and many others are in the research phase.
High Intensity Focused Ultrasound (HIFU) allows to induce a variety of thermal and mechanical effects, such as local hyperthermia, thermal ablation, or histotripsy. Since HIFU is completely non-invasive and free of any ionizing radiation, it is a very patient friendly interventional treatment option that finds already clinical application for a variety of medical disorders. The interaction of HIFU with tissue, as well as with ultrasound-responsive materials, leads to a wide range of bioeffects and applications such as drug delivery.
Why is this important? Why now?
Though HIFU has been known and studied for almost a century, clinical use only recently became feasible, primarily through the combination of HIFU with diagnostic ultrasound (US-HIFU) or magnetic resonance imaging (MR-HIFU) for image guidance. Image guidance provides therapy planning but also provides feedback during therapy to control the sonication with respect to reaching the treatment goal. Today, around thirty HIFU applications obtained regulatory approval and many others are in research phase. The increasing number of clinical trials that compare HIFU to standard of care for several indications indicates the increasing role of HIFU as an interventional therapeutic option. The future question to address is how clinical adoption can be increased.
Subject and subtopics
The special collection is open for invited reviews and submission of original work addressing HIFU related topics that are either technical or application oriented such as ablation, hyperthermia, temperature induced drug delivery as well as immunotherapy, liquid biopsy and histotripsy. Experimental work and validation purely on cells assays in vitro will not be considered. Topics such as pressure-mediated drug delivery and sonodynamic therapy fall outside the scope of this collection.
Holger Grüll holds a full professor position at the Department of Radiology, University Hospital of Cologne leading the high intensity focused ultrasound (HIFU) related research including clinical translation and trials (https://exim.uni-koeln.de/home). Main topics of research are applications of HIFU in ablation, hyperthermia and histotripsy for local drug delivery and immune therapy especially for treatment of pancreatic cancer and sarcomas. With a background in chemistry, much research is also devoted to new ultrasound-responsive materials and drug delivery systems. His chair is also associated with the department of Chemistry at the University of Cologne, reflecting the chemistry related research.
Roel Deckers currently holds an Associate Professor position at the UMC Utrecht. His main research interests are focused ultrasound therapy of breast cancer and ultrasound-mediated drug delivery. He plays an important role in the interface between clinical research and these advanced image-guided therapies.
Disclosure Statement:
Prof. Holger Grüll and Dr. Roel Deckers declares no conflict of interest
