FDA has developed and qualified a tool for assessing the effects of high intensity therapeutic ultrasound (HITU) devices before testing them in humans.
The tool features a material designed to mimic the behavior of tissue to enable companies to assess and improve the safety of their HITU devices early in the R&D process.
As with other technologies created through the Medical Device Development Tools (MDDT) program, FDA says the new tissue-mimicking material can streamline development and regulatory review.
FDA set up the MDDT program to support the development of validated and qualified methods, materials and measurements. The goal was to reduce the risk and uncertainty of device development by providing companies with a set of tools and techniques accepted by FDA, as opposed to assessing the tools used by industry on a case-by-case basis.
Officials identified a need for a qualified HITU assessment tool after detecting an increase in filings for approval of such devices. HITU devices use ultrasound to treat diseases including cancer and uterine fibroids. To be safe and effective, the devices must precisely administer the ultrasound.
Developers of HITU devices were using their own formulations to create tissue-mimicking materials, known as phantoms. These formulations enabled companies to assess devices but the patchwork of unqualified tools in use introduced variability and uncertainty the MDDT program is designed to prevent.
FDA's solution, developed by scientists at the Office of Science and Engineering Labs, is a hydrogel matrix combined with chemicals including different sized aluminum oxide particles. Tests run by FDA show the material approximately mirrors the acoustic properties of human non-fatty soft tissues. The properties of these tissues vary but the characteristics of the mimic fall within the clinically-relevant range, according to FDA.
To help companies test HITU devices, FDA has provided a manufacturing protocol for the mimic. The protocol is a step-by-step guide to how to produce a material suitable for use in the acoustic testing of HITU devices.
The development of the tissue mimic means MDDT has now qualified tools in every category of the program, which also covers biomarker tests and clinical outcome assessments. Previously-qualified MDDTs include a software module designed to help neuroradiologists classify brain contusions. FDA wants to expand the MDDT program "to as many areas as possible."