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05 omedical ultrasound imaging to ultrasonic non-destructive testing iewed simply as a test object. However, in practice, the two It is possible to liken biomedical ultrasound im (NDT) if the human body is viewed simply as a test object. Hou applications of ultrasound are very different. Fixplain why this is the case, considering, for example and amongst others: the nature of the human body compared with the nature of test objects in NDT; the ultrasonic mode that propagate in the human body_compared with those in test objects: the instrumentation, imaging techniques and parameters measured for each subjects and the modes of display in biomedical imaging and NDT. [20]

Answer 1

Ultrasound imaging in humans uses sound waves to produce the pictures of the inside of the body. It is used to help diagnose the causes of pain, swelling and infection in the body's internal organs and to examine a baby in pregnant women and the brain and hips in infants. It's also used to help guide biopsies, diagnose heart conditions, and assess damage after a heart attack. Ultrasound is safe, noninvasive, and does not use ionizing radiation.

NICE NANCY REX OB/GYN Map4 103200CA(LMP) = 12020 MTZ6.5 GE CN64 Вси DR60 G60 CRL 6 56cm CRL 6 5603 XCRL 6. 85cm 1206D+D 1286D4D 1381D4D 02/14/01 02/14/01 02/12/01

The Sonographer usually holds a transducer, a hand-held device, like a wand, which is placed on the patient's skin. It produces Ultrasound waves which is a sound that travels through soft tissue and fluids, but it bounces back, or echoes, off denser surfaces. This is how it creates an image. The term "ultrasound" refers to sound with a frequency that humans cannot hear. For diagnostic uses, the ultrasound is usually between 2 and 18 megahertz (MHz).

Two properties of reflected sound is measured i.e. first the echo time and second the Doppler shift to measure the distance of internal organs and structures and the speed of movement of those structures.

Ultrasound imaging near the surface of the body is capable of resolutions less than a millimeter. The resolution decreases with the depth of penetration since lower frequencies must be used (the attenuation of the waves in tissue goes up with increasing frequency.) or in other words Higher frequencies provide better quality images but are more readily absorbed by the skin and other tissue, so they cannot penetrate as deeply as lower frequencies. On the other hand lower frequencies penetrate deeper, but the image quality is inferior.

Ultrasonic Non Destructive Testing-

Non destructive testing is a method of finding defects in an object without harming the object. Often finding these defects is a very important task. In the aircraft industry, NDT is used to look for internal changes or signs of wear on airplanes. Discovering defects will increase the safety of the passengers. The railroad industry also uses nondestructive testing to examine railway rails for signs of damage. Internally cracked rails could fracture and derail a train carrying wheat, coal, or even people. If an airplane or a rail had to be cut into pieces to be examined, it would destroy their usefulness. With NDT, defects may be found before they become dangerous.

Like in the case of human ultrasound, Ultrasonic sounds with high frequencies are emitted from a transducer into an object and the returning waves are analyzed. If an impurity or a crack is present, the sound will bounce off of them and be seen in the returned signal. In order to create ultrasonic waves, a transducer contains a thin disk made of a crystalline material with piezoelectric properties, such as quartz. When electricity is applied to piezoelectric materials, they begin to vibrate, using the electrical energy to create movement.

Main difference between the two processes are the levels of frequencies used.
In humans, low level frequency is used as the attenuation of the waves in tissue goes up with increasing frequency as higher frequencies have shorter wavelengths are absorbed by the cells and tissues and hence they are not penetrating enough for reflecting back the sound to the receiver.
Which is not the case in NDT as it uses only the high frequency as it deals with mostly the metals. As the matter of the fact higher frequencies have higher wavelengths and maximum resolution of any imaging process is proportional to the wavelength of the imaging wave.