Lakhasly

Ultrasound pictures of the body

Human ears respond to sound in the frequency range of about 20-20000 Hz, although many animals can produce and hear sounds of considerably higher frequencies.To obtain diagnostic information about the depth of structures in the body, we send pulses of ultrasound into the body and measure the time required to receive the reflected sound (echoes) from the various surfaces in it. This procedure is called the A Scan method of ultrasound diagnosis.For example, bats emit blips of ultrasonic frequencies (30 to 100 kHz) and navigate by listening to the echoes.It was discovered during World War II that man can use ultrasound in much the same way bats can, The navy developed sonar (Sound NAvigation and Ranging).The time required for the sound pulses to be reflected gives information on the distance to the various structures or organs in the path of the ultrasound beam.This gives a good coupling at the skin and greatly increases the transmission of the ultrasound into the body and of the echoes back to the detector.a method of locating under water objects, such as submarines, with ultrasound echoes.Ultrasound generators are often simply referred to as transducers.

Ultrasound pictures of the body

Human ears respond to sound in the frequency range of about 20-20000 Hz, although many animals can produce and hear sounds of considerably higher frequencies. For example, bats emit blips of ultrasonic frequencies (30 to 100 kHz) and navigate by listening to the echoes. It was discovered during World War II that man can use ultrasound in much the same way bats can, The navy developed sonar (Sound NAvigation and Ranging). a method of locating under water objects, such as submarines, with ultrasound echoes. After World War II medical engineers developed techniques for using ultrasound in diagnosis.

Basically, an ultrasound source sends a beam of pulses of 1 to 5 MHz sound into the body. The time required for the sound pulses to be reflected gives information on the distance to the various structures or organs in the path of the ultrasound beam.

While there are several methods of generating ultrasound, the most important for medical applications involves the piezoelectric effect. This effect was discovered by Jacques and Pierre Curie in about 1880.

A device that converts electrical energy to mechanical energy or vice versa is called a transducer. Ultrasound generators are often simply referred to as transducers. Each transducer has a natural resonant frequency of vibration. The thinner crystal, the higher the frequency at which it will oscillate. Pulses of ultrasound are transmitted into the body by placing the vibrating crystal in close contact with the skin, using water or a jelly paste to eliminate the air. This gives a good coupling at the skin and greatly increases the transmission of the ultrasound into the body and of the echoes back to the detector. The same transducer that produced the pulse serves as the detector. The weak signals are then amplified and displayed on an oscilloscope. Many of the applications of ultrasound in medicine are based on the principles of sonar. In sonar a sound wave pulse is sent out and is reflected from an object; from the time required to receive the echo and the known velocity of sound in water, the distance to the object can be determined.

To obtain diagnostic information about the depth of structures in the body, we send pulses of ultrasound into the body and measure the time required to receive the reflected sound (echoes) from the various surfaces in it. This procedure is called the A Scan method of ultrasound diagnosis.