Dual frequency phased array transducers allow performing third or fourth harmonic imaging. This array design contains two different types of elements arranged in an interleaved pattern (odd and even elements). The elements can work individually and at a distinct frequency enabling separate transmission and receiving modes.

'ALOKA, the innovator in ultrasound is the longest operating ultrasound company in the world with its main headquarters located in Tokyo, Japan.
The history of ALOKA began in 1950 when the medical equipment department of Japan Radio Company became the independent company, Medical and Physical Institute Co., Ltd.
In 1960, we developed the world's first commercially available diagnostic ultrasound system.
In 1976, our company name changed to ALOKA, which, in ancient Sanskrit, means 'Ray of Hope'.
ALOKA's ultrasound systems have been sold in the United States through distributors since the early 70s. Some of our major distributors included Johnson & Johnson Ultrasound and Corometrics Medical Systems, Inc., which also provided service for the ALOKA equipment.
In 1986 the first ALOKA office was opened in the United States.
And on January 1, 1991, ALOKA America began direct sales of ultrasound units.
All US sales, distribution and service are provided through our US headquarters located in Wallingford, Connecticut . In addition, we have sales, service and clinical applications representatives strategically located throughout the country to provide exceptional service to our customers.'

In November 2010 Hitachi Medical announced the acquisition of ALOKA.

Ultrasound Systems:

Common ultrasound supplies that are often used in conjunction with ultrasound imaging:
Common ultrasound accessories that are often used in conjunction with ultrasound imaging:
Consult with ultrasound equipment vendors or professionals in the field to determine the specific accessories and supplies that best suit your imaging needs and specialty. See also Equipment Preparation, Environmental Protection, Portable Ultrasound Machine, Ultrasound Technology, Ultrasound System Performance and Sonographer.

The wider the ultrasound beam, the more severe the problem with volume averaging and the beam-width artifact, to avoid this, the ultrasound beam can be shaped with lenses.
Different possibilities to focus the beam:

Conventional multi-element transducers are electronically focused in order to minimize beam width. This transducer type can be focused electronically only along the long axis of the probe where there are multiple elements, along the short axis (elevation axis) are conventional transducers only one element wide. Electronic focusing in any axis requires multiple transducer elements arrayed along that axis. Short axis focusing of conventional multi-element transducers requires an acoustic lens which has a fixed focal length.
For operation at frequencies at or even above 10 MHz, quantization noise reduces contrast resolution. Digital beamforming gives better control over time delay quantization errors. In digital beamformers the delay accuracy is improved, thus allowing higher frequency operation. In analog beamformers, delay accuracy is in the order of 20 ns.
Phased beamformers are suitable to handle linear phased arrays and are used for sector formats such as required in cardiography to improve image quality. Beamforming in ultrasound instruments for medical imaging uses analog delay lines. The signal from each individual element is delayed in order to steer the beam in the desired direction and focuses the beam.
The receive beamformer tracks the depth and focuses the receive beam as the depth increases for each transmitted pulse. The receive aperture increase with depth. The lateral resolution is constant with depth, and decreases the sensitivity to aberrations in the imaged tissue. A requirement for dynamic control of the used elements is given. Since often a weighting function (apodization) is used for side lobe reduction, the element weights also have to be dynamically updated with depth.

See also Huygens Principle.

Ultrasound machines, widely used in medical imaging, are essential tools in the field of diagnostic ultrasound. These devices utilize high-frequency sound waves to create real-time images of internal body structures. Ultrasound machines consist of several key components that work together to generate diagnostic images. These include:
B-mode machines represent the vast majority of machines used in echocardiology, obstetrical scans, abdominal scans, gynecological scans, etc. B-mode ultrasound machines usually produce the sector (or pie segment-shaped) scans. These ultrasound scans require either a mechanical scanner transducer (the transducer moves to produce the sector scan), or a linear array transducer operated as a phased array.


Ultrasound machines come in different types, each catering to specific clinical needs. The two primary types are stationary and portable ultrasound machines:


See also Handheld Ultrasound, Ultrasound System Performance, Equipment Preparation, Coaxial Cable, and Microbubble Scanner Modification, Environmental Protection and Ultrasound Accessories and Supplies.