Medical ultrasonography

Medical ultrasonography - Typical ultrasound diagnostic scanners operate in the frequency range of 2-18 MHz, although frequencies up to 50-100 MHz has been used experimentally in a technique known as biomicroscopy in specific areas, such as room front of the eye. [Citation needed] The choice of frequency is a compromise between spatial resolution and imaging depth photo: lower frequencies produce less resolution but image deeper into the body. The sound waves of higher frequencies have wavelengths which are smaller and therefore capable of reflecting or scattering of small structures. The frequency of sound waves higher has a larger attenuation coefficient and thus more easily absorbed in the tissues, which limits the depth of penetration of the sound waves into the body.

Ultrasonography (ultrasound) are widely used in medicine. It is possible to perform the diagnostic and therapeutic, using ultrasound to guide interventional procedures (for example for a biopsy or drainage of fluid collections). Sonographers are professionals who perform scans are then generally interpreted by a radiologist, a physician who specializes in the application and interpretation of a variety of medical imaging modalities, or by Cardiologists in the case of cardiac ultrasound (echocardiography). Sonographers typically use hand-held probe (called a transducer) that is placed directly and moving patients. Increasingly, clinicians (physicians and other health professionals who provide direct patient care) to use ultrasound in their office and hospital practice, for efficiency, inexpensive imaging, diagnostic dynamic facilitate treatment planning, while avoiding exposure to ionizing radiation.

Effective body ultrasound imaging of soft tissue. Surface structures such as muscles, tendons, testes, mammary glands, thyroid and parathyroid and the neonatal brain are imaged at a higher frequency (7-18 MHz), which provides better axial and lateral resolution . Deeper structures such as the liver and kidney are imaged at a frequency of 1-6 MHz below the lower axial and lateral resolution, but penetration.

Produce sound waves
A sound wave is typically produced by a piezoelectric transducer encased in a housing which can take several forms. Strong, short electrical pulses from the ultrasonic transducer to the ring at the desired frequency. The frequency can be anywhere between 2 and 18 MHz. The sound is carried either by the shape of the transducer, a lens on the front of the transducer, or a complex set of control pulses of the machine ultrasonic scanning (beamforming). This orientation produces a sound wave in form of an arc of the transducer face. Wave propagates in the body and is developed to a desired depth.

Transducers older technology focusing the beam with lenses physical. Newer technology transducers use phased array techniques to enable ultrasound machine to change the direction and depth of field. Practically all piezoelectric transducers are made of ceramics.

Materials on the face of the transducer to enable the sound transmitted efficiently in the body (generally appears to be a rubber layer, in the form of impedance matching). In addition, water-based gel is placed between the patient's skin and the probe.

Sound waves partially reflected from the layers between different networks. More specifically, the sound is everywhere where there are density changes in the body: eg blood cells in blood plasma, small structures in organs, etc. Some of the reflections return to the transducer.