A logarithmic measure of sound loudness closely related to the decibel. The unit decibel is used for objective measurements, that means, they measure the actual pressure of the sound waves as recorded using a microphone. The unit phon is used for subjective measurements, which means, measurements made using the ears of a human listener.
A sound has the loudness 'p' phon if it seems to the listener to be equal in loudness to the sound of a pure tone of the frequency 1 kilohertz and strength 'p' decibel. A measurement in phons will be similar to a measurement in decibel, but not identical, since the perceived loudness of a sound depends on the distribution of frequencies in the sound as well as the pressure of the sound waves. In the U.S., sound loudness is frequently measured in sones rather than phons: a sound of loudness x sones has loudness 10 log2 x + 40 phons.

See also Acoustic Noise.

A hydrophone is a special transducer for underwater measurement of acoustic fields. The diameter of a hydrophone should be smaller than the wavelength of the measured ultrasound, in combination with a large bandwidth.

Handheld ultrasound systems are portable devices for smartphone or tablet and are increasingly common in emergency, intensive care and veterinary medicine, but also in the pocket of the stationary doctor. This type of ultrasound machine enables immediate diagnoses directly on site (handheld point-of-care-ultrasound / HPOCUS) and quickly provide information regarding the patient's further care. Handheld ultrasound machines fit into a single-use plastic cover and can be easily disinfected, making them particularly useful in infectious environments.
The most striking advantage of handheld POCUS devices is the small footprint. The design is very compact, lightweight (approx. 200 g/0,44 lbs. - 500 g/1,1 lbs) and flexible. Due to this compactness and the necessary technical compression, the quality of the imaging is still limited compared to 'high-end devices', but sufficient to the extent that handheld ultrasound devices are already successfully used in many medical disciplines.
Depending on the model, handheld ultrasound systems run on Android, iOS, Windows or proprietary operating systems. They are connected to the end device via USB cable or wirelessly via Bluetooth or WiFi. The respective end device is used as an ultrasound monitor to display the ultrasound images. The associated app is operated via touchscreen, although some devices have a few buttons, e.g. for recording ultrasound images or freeze images. The images can be stored and managed on the end device itself, the inserted memory card or in the cloud. Theoretically, also a private smartphone can be connected, but this can lead to complications with reimbursement.
See also Portable Ultrasound Machine, Ultrasound Technology, Environmental Protection, Ultrasound Accessories and Supplies and Sonographer.

Pressure is the force per unit area applied on a surface in a direction perpendicular to that surface.
Pressure can also be described as a form of potential energy in a fluid. The maximum pressure of the fluid medium obtained during propagation of an ultrasonic pulse.
The negative peak pressure is the peak rarefaction pressure attained during the negative portion of a propagating ultrasound pulse in a medium such as tissue.
Sound pressure can be measured using a microphone in air and a hydrophone in water. The SI unit for sound pressure is the Pascal.
Blood pressure is the pressure exerted by the blood on the walls of the blood vessels.

See also Rarefactional Pressure, Low Intensity Pulsed Ultrasound, and Projector.

The Germany-based pharmaceutical company is the result of the take-over of Schering AG by Bayer AG in 2006. The Bayer Schering Pharma AG is part of the Bayer HealthCare AG, which represents the pharmaceutical part of the Bayer Group.
The company makes ultrasound, x-ray and MRI contrast media, drugs for treating cancer, multiple-sclerosis, heart and nervous system disorders and severe skin conditions.
In general, its activities are focused on four business areas: Fertility control & hormone therapy, diagnostics & radiopharmaceuticals, dermatology as well as specialized therapeutics for disabling diseases in the fields of the central nervous system, oncology and cardiovascular system.
Currently, Bayer Schering Pharma discontinued the manufacturing and development of ultrasound contrast agents.

Ultrasound Contrast Agents: