Radiation Force Balance for Diagnostic and Therapeutic Medical Ultrasound
Ultrasonic power is a primary acoustic quantity and its measurement is required by international specification standards for both diagnostic and therapeutic ultrasound systems. In order to comply with the US FDA 510(k) regulatory requirements, IEC61157 and IEC61689, medical equipment manufacturers are required to measure ultrasonic power. The ability to measure it accurately is vital to ensuring the correct operation and safe use of ultrasound in medicine.
Typically scanned hydrophone measurements of acoustic power have an uncertainty that is no better than 20%, whereas radiation force balances often measure with uncertainty <10%.
The Radiation Force Balance (RFB) from Precision Acoustics is a highly specified model, which can be used for the measurement of medical diagnostic and physiotherapy equipment in the frequency range 1 MHz to 20 MHz and the power range 10 mW to >100 W.
The Precision Acoustics RFB can be used either with an ‘absorbing well’ target or with a suspended target which allows the design to be tailored to individual requirements for frequency, power and transducer geometry.
The RFB can be used as a stand-alone device or connected to a PC to provide a permanent record of results in an approved Quality System.
Each RFB is supplied with:
- Two targets –an absorbing well and a suspended target suitable for the power levels
to be measured.
- A NPL calibration certificate, traceable directly to the UK Primary Standard for ultrasound power.
- Approved measurement protocol and user instructions.
- Software for data acquisition and analysis.
- Retort stand to hold the transducer under test.
Full Range RFB Specification:
Precision Acoustics RFB’s is for a highly specified model suitable for the majority of medical diagnostic and physiotherapy ultrasound equipment: Using the suspended target the power generated by HIFU transducers can be measured
- Calibrated frequency range 1 MHz to 20 MHz*.
- Power range 10 mW to >100 W but the calibration range is 20 mW to 10 W*.
- Overall measurement uncertainty* – for 50 mW to 5 W, less than +/-7% at 95% confidence.
- For power levels greater than 100mW the typical type A (random) measurement uncertainties is typically only 1%.
- Maximum transducer diameter for absorbing well target 5 cm* but the suspended target will accommodate large transducers – contact us with your specific requirements.
*The RFB may be used outside of this range with increased uncertainty levels
Listed are the options available for NPL calibrations which are traceable to the UK’s Primary Standard.
- Calibration at 1 MHz and 3 MHz, Powers: 0.1 W, 0.5 W, 1 W, 5 W and 10 W.
- Calibration at single frequency at Powers to be agreed.
- Calibration at 1 MHz and 3 MHz, Powers: 0.1 W, 0.5 W, 1 W, 5 W and 10 W AND 3 Outputs in the range 10 mW to 1 W at 0.928 MHz and 3.151 MHz AND 2 Outputs in the range 10 mW to 200 mW at 5.287 MHz and 7.415 MHz and 9.541 MHz.