Ultrasound imaging products used nowadays for medical diagnostics and therapies have become indispensible. The advantage of this method is that the sound waves, having a frequency of between 1 MHz and 40 MHz at a medium sound intensity of 100 mW/cm2, are not harmful to animal or human tissues. The basic technology, also called sonography, makes use of the different reflections of the ultrasound on the boundaries between tissue and air, acoustically different tissues and on the boundaries between bone and tissues. The main applications in the medical sector include gall bladder and kidney examinations, cardiology, gynecology, tumor detection, radiotherapy and ophthalmology.
In addition to electronics for the sound generation, an ultrasound imaging product comprises signal processing and image display, a variety of interfaces for the connection of a monitor and printer as well as for storage media or a video camera. The ultrasound probe (transducer head) is connected to the main unit via a cable. Printouts (sonograms) or video recordings can be prepared as documentation from the monitor images. Ultrasound imaging products are available in a range of different models, for example, small portable systems in personal digital assistant (PDA) format or large desktop types.
Due to the increase in computing power, and particularly through the progress in digital signal processing, the image quality of ultrasound imaging products has continued to improve in recent years. For example, by means of digital sound wave coding it is possible to clearly differentiate between ambient noise and the sound wave used for image generation and thus improve the image resolution. Furthermore, beside the two-dimensional, color-coded Doppler method, the amplitude-coded power Doppler technology was developed. Spatial still images are possible with 3D ultrasound imaging products. 4D ultrasound imaging even permits three-dimensional displays in real-time. Cross section views of a particular organ from any viewing angle can be generated or a virtual journey can be made through the human body.