Hydrophone area-averaging correction factors in nonlinearly generated ultrasonic beams

Laser-generated ultrasonic beams.

In-plane ultrasonic needle tracking using a fiber-optic hydrophone.

PURPOSE Accurate and efficient guidance of needles to procedural targets is critically important during percutaneous interventional procedures. Ultrasound imaging is widely used for real-time image guidance in a variety of clinical contexts, but with this modality, uncertainties about the location of the needle tip within the image plane lead to significant complications. Whilst several methods...

Absolute Hydrophone Calibration to 40MHz Using Ultrasonic Far-Field

An absolute hydrophone calibration technique using ultrasonic far-field with optical interferometry was extended to 40MHz to evaluate the sound pressure amplitude generated by medical ultrasound equipment. A 1-mm nominal radius plane transducer was the calibration sound source for an ultrasonic far-field at 50mm propagation distance at 40MHz. The transducer’s effective radius was 0.88mm at 40MH...

Tailoring ultrasonic beams with optoacoustic holography

A combination of laser-induced ultrasound generation and ultrasonic holography for spatial control of the generated ultrasonic pulse is presented. Ultrasound is produced by absorption of laser pulses at an absorbing layer in a water tank via the optoacoustic effect. In order to produce a defined ultrasonic frequency in the MHz range, the laser pulses are harmonically time-modulated using an aco...

Fibre-optic probe hydrophone for ultrasonic and shock-wave measurements in water

Aimed at lithotripter acoustic output measurements, a new fibre-optic probe hydrophone overcomes most of the problems involved with the use of piezoelectric hydrophone technology in non-linear ultrasonic and shock-wave fields. The fibre-optic principle allows for extremely wide bandwidth (larger than 1 GHz) and superior electromagnetic shielding. Contrary to hitherto existing hydrophones a high...