Ultrasound is a long established treatment for kidney stones, soft tissue injuries and also surgical applications including cataract surgery. The last decade has seen a dramatic increase in new uses of ultrasound as a surgical and therapeutic tool, some using very high power levels. An inability to deliver the required ultrasound dose for clinical treatment accurately is leading to potential over, or under, exposure to the patient. This can cause harm or fail to provide the anticipated benefit, and is hampering the introduction of new ultrasound curative or restorative treatments.
The EMRP project HLT03 Dosimetry for Ultrasound Therapy developed the basis for High Intensity Focused Ultrasound (HIFU) dose determination and the heating effects induced using validated modelling methods and phantoms to replicate the body during treatment.
- Developed ultrasound calibration sources and improved test methods for tissue-mimicking materials used in HIFU body test models.
- Produced validated body test models and measurement devices suitable for transferring traceability from the laboratory to the clinical HIFU machine based on an infrared camera that enables monitoring of the temperature distribution on the phantom surface.
- Developed a complex heat propagation model for HIFU that calculates HIFU scattering off rib cage surfaces and enables the optimisation of treatment to the targeted organs while minimising heating to the ribs.
- Investigated the effect of heating rate on tissue over time and identified that slow heating offered a better treatment than rapid heating.
The enhanced European measurement infrastructure for therapeutic ultrasound resulting from the project is already being used by equipment manufacturers to assess and validate ultrasound instrumentation. The project team has made contributions to draft documentary standards and a published regulation. One standard (IEC60601-2-62) is part of a series of standards within the European Medical Devices Directive and it is also referenced by the US Food and Drugs Administration (FDA) amongst others, meaning that all manufacturers of HIFU equipment must comply with it. Improved equipment assessment and validation against IEC standards is helping manufacturers bring HIFU equipment to market and establishing a more homogenous global regulatory and purchasing environment. This will give healthcare providers a greater range of reliable therapies and the ability to tailor treatment plans.
Coordinator: Adam Shaw, NPL (UK)
For more information, please contact the EURAMET Management Support Unit:
Phone: +44 20 8943 6666