![]() ![]() Matching layer is item situated between the PE material and the phantom sample or the patient. The ingredient utilized as a PE element made of crystal, like plastic and lead zirconate titanate which is the most common ingredient to be used basic components of an ultrasound probe are shown in Figure 1 In addition to the crystal which was described before, both of backing and matching materials are very significant components of the system. ![]() When a voltage utilized by PE element, this will produce a pressure signal wave. Furthermore, the main function of the probe is sending ultrasound energy into body organs or into samples and then receiving the reflected signal echoes that may be processed via ultrasound unit into images displayed on a screen monitor. This process called piezoelectric (PE) influence. The transducer has an ingredient that has the ability to produce ultrasound signal waves, and these signals occur when the electric current passes through the probe ingredient. The probe or the transducer is a necessary component in an ultrasound system. The relationship between the wavelength (λ), frequency (f), and the velocity (c) given by this formula (2): The speed of sound relies on both the compressibility and density of the medium and variates largely with materials variation. When the frequency exceeds 20KHz, the human cannot hear it, and this process called ultrasound. In contrast, the quantity of times the signal wave fluctuates (oscillates) during a cycle count each second known as the frequency (f). The distance between both of rarefaction and compression or between each two spots which regenerate on the sinusoidal signal wave known as the wavelength (λ). The energy (power) traveling occurs when the signal wave front in the direction of power propagate, called as a longitudinal wave. Rarefaction is an area where the elements furthest from each other, whereas the compression is an area where the elements are closest together. The sound is a mechanical power (energy) which travel or propagate during flexible (elastic) continuous medium by the rarefaction and compression of elements that compose it. ![]() This article displayed the transmission ultrasound of brain and many of researches done for medical ultrasound field. The first article on medical imaging ultrasound was published in 1942 by Dr. The usage of ultrasound into medical imaging field dates back more than 55 years and it launched was first with a therapeutic field rather than the diagnostic field. Diagnostic ultrasound in the medical field is a form that utilizing ultrasound power and acoustic features of the organs of human body or phantoms to produce an image from constant and moving tissue. Ultrasound is the term that describes the sound signal wave's pulse frequencies above the domain of real human hearing, and their publishing (propagation) in a medium. Finally, we explained spectral Doppler sign waveforms to show both the normal and abnormal signs waveforms that are individual to the common carotid artery, because these signs are important for both the radiologist and sonographer to perceive both the normal and abnormal in a spectral Doppler show. Furthermore, we discussed the color and spectral flow model of Doppler ultrasound. The aim of this review is to explain the physical principles behind the medical Doppler ultrasound, also, to use some of the mathematical formulas utilized in the medical Doppler ultrasound examination. ![]() Thus, it is significant for the operator and the clinicians to understand the normal and abnormal diagnostic in a spectral Doppler show. The sign waveform is individual to each vessel. The normal and abnormal sign waveforms can be shown by spectral Doppler technique. Medical Doppler ultrasound is usually utilized in the clinical adjusting to evaluate and estimate blood flow in both the major (large) and the minor (tiny) vessels of the body. ![]()
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