The Therapeutic Ultrasound Program in the FDA’s Center for Devices and Radiological Health (CDRH) conducts regulatory science research to help ensure patient access to innovative therapeutic ultrasound devices that are safe and effective. This is one of 20 research programs in CDRH’s Office of Science and Engineering Laboratories (OSEL).

Therapeutic Ultrasound and Medical Devices

Therapeutic ultrasound  is a burgeoning technology. Medical therapeutic ultrasound devices encompass a wide range of technologies including extracorporeal shock wave therapy, high and low intensity therapeutic ultrasound, and applications such as ultrasound physiotherapy, tumor ablation, brain therapy, and drug delivery.

The FDA is receiving a steadily increasing number of therapeutic ultrasound device submissions covering a wide range of clinical applications including:

• Brain applications (essential tremor, Parkinson's disease, drug delivery, thrombolysis)
• Cardiovascular applications (vessel occlusion, hypertension)
• Pain management (physiotherapy, brain stimulation for pain relief)
• Immunotherapy.

However, several gaps remain between the clinical use of therapeutic ultrasound technology and the development and characterization of the testing needed to assess clinical safety. Appropriate testing methods that cut across these clinical applications are needed to stimulate innovation and safe adoption of this technology.

Regulatory Science Gaps and Challenges

Major regulatory science gaps and challenges that drive the Therapeutic Ultrasound Program are:

• Lack of acoustic and thermal measurement and simulation techniques for therapeutic ultrasound device output characterization.
• Lack of regulatory tools for manufacturers to provide appropriate thermal safety data, since there are no standards or guidance for thermal safety of therapeutic ultrasound devices.
• The need of test phantoms for medical ultrasound device characterization.
• The need of appropriate phantom models and modeling methods for imaging guidance and therapy planning.

The Therapeutic Ultrasound Program is intended to fill these knowledge gaps by fostering the development of test methods and computational techniques that help manufacturers assess the safety and performance of their devices. This work also makes the FDA better prepared for addressing therapeutic ultrasound devices issues at both the premarket and postmarket stages in the medical device lifecycle.

Therapeutic Ultrasound Program Activities

The Therapeutic Ultrasound Program focuses on regulatory science research in these areas:

• Techniques to understand the reliability and repeatability of hydrophone High-Intensity therapeutic ultrasound (HITU) characterization.
• Methods for correcting for the effects of spatial averaging in hydrophone measurements of HITU pressure fields and acoustic radiation force impulse.
• Measurement of ultrasound power accurately over all frequencies of regulatory interest.
• Ultrasound-compatible matrix materials and microfluidic design for growing cells capable of contrast injection and flow.
• Ultrasound-compatible, optically-transparent, three-dimensional in vitro BBB “lab-on-a-chip.”

For more information, email OSEL_therapeuticultrasound@fda.hhs.gov