Ultrasound is a type of sound waves with frequencies greater than the upper limit of human hearing. It is also known as supersonic or ultrasonic sound. The term ultrasound refers to both the frequency and the energy of the sound waves. Ultrasound waves are used in many different fields, including medical diagnostics, sonar technology, and material science.
Medical ultrasonography uses ultrasound waves to create images of internal organs and tissues. This non-invasive imaging technique is used to diagnose a variety of conditions, such as tumors, heart disease, and kidney stones. Sonar technology uses ultrasound waves to detect underwater objects, such as submarines and fish. This information is then used for navigation purposes. Material science uses ultrasound waves to study the properties of materials, such as their elasticity and density.
Ultrasound waves are produced by vibrating objects, such as piezoelectric crystals or piezoelectric transducers. When these objects are subjected to an alternating electric field, they vibrate at a high frequency and generate ultrasound Waves propagate through solids, liquids, and gases alike; however, they travel farthest through solids because there are no medium molecules to scatter them in this state. The speed of sound varies depending on the medium through which it is travelling; for example, it travels faster through water than it does through air. However, all sounds travel at approximately 340 m/s in dry air at room temperature regardless of frequency .
The wavelength of an ultrasound wave can be calculated using the following equation: = / where represents wavelength (m), represents speed (m/s), and represents frequency (Hz). The higher the frequency of an ultrasound wave ,the shorter its wavelength will be . For example ,a 3 MHz wave has a wavelength of 0 .1 mm while a 1 GHz wave has a wavelengthof 0 .3 mm .
Different types of medical diagnostic procedures make use of different frequencies Ultrasound ranging from 20 kHz- 10 MHz are commonly used for obstetric examinations while those between 2-18 MHz find applications in cardiac evaluations 3D/4D fetal echocardiography , Doppler studies etc Lower frequencies(20 Hz – 200 KHz) provide good penetration but poor resolution whereas higher frequencies(10 Mhz -50Mhz) vice versa creating grey scale images In contrast color flow mapping & power Doppler utilize lower frame rates with wider scanning angles(60 degrees )to achieve good temporal & spatial resolution respectively Building on B mode imaging newer techniques like elastography strain ratio imaging harmonic imaging microbubble contrast agents have been developed which improve diagnostic capabilities even further 3D Printing: A new frontier? : With recent advances in three-dimensional(3D) printing technology ,it may soon be possible create customized implants & prosthetics using patient specific data derived from ultrasounds Virtual reality: What was once considered pure fiction now appears poisedto become reality sooner rather than later Augmented reality systems that can superimpose three dimensional(3D) images over real life objects have already been demonstrated Using similar principles it should theoretically be possible develop fully immersive environments for surgical training planning etc