Ultrasound Machines – How Ultrasound Works

Ultrasound machines have become very common nowadays as several cases, both minor and serious, require it for diagnostic purposes. It is important to understand how ultrasound works to fully identify possible problems in the human body and determine the right methods that can alleviate these. There are different types of ultrasound, each used depending on the current case and the organ that needs to be examined.

The Types of Ultrasound

The basic ultrasound machine has a transducer probe which receives and sends sound waves. It shows a two-dimensional image or presents the slice of a three-dimensional object. 3D ultrasound imaging has been developed wherein many two-dimensional images are taken through the use of probes moving along the body surface or inserted probes rotating simultaneously. The 2D scans will later be combined using specialized computer software, leading to 3D images.

The third kind of ultrasound is called the Doppler ultrasound which is based on the Doppler Effect. Once the object reflecting ultrasound waves moves, the frequency of the echoes change, thereby producing a higher frequency if moving toward the probe or a lower frequency if moving away from the probe. The frequency changed will depend on the speed of the moving object. Doppler ultrasound is then used to measure frequency change of echoes to identify the speed of moving objects. It comes in useful for measuring blood flow rate through major arteries and the heart.

Other General Functions

Ultrasound machines are used for a variety of functions and settings, ranging from gynecology to oncology. It is very advantageous since structures can be observed and studied without the need for radiation. It is also faster compared to X-rays and other radiographic methods.

Some of the major uses in obstetrics and gynecology include measuring fetal size to know the due date, checking the placenta’s position to determine if it is not developing well over the uterus opening, identifying the gender of the baby, detecting ectopic pregnancy, determining if there is enough amniotic cushioning for the fetus and monitoring the fetus during special procedures like amniocentesis. In urology, ultrasound can be used to look for kidney stones and detect prostate cancer. In cardiology, blood flow can be measured in the heart and major blood vessels.

The Mechanism

During ultrasound examination, the transducer functions so you can view the target organ and make pictures for further observation. The transducer produces sound and discovers the echoes bouncing back when it is placed over the body organ being viewed. An echo is created when the produced sound hits a border between tissues that conduct sound uniquely.

The computer analyzes the echoes. Ultrasound waves pass through soft tissues and fluids easily, so the process is very useful when examining fluid-filled organs like the uterus, liver and gallbladder. The waves cannot penetrate gas or bone, making it ineffective when viewing regions surrounded by bone or places with gas. Most parts of the body can be examined by ultrasound.


Ultrasound machines involve a non-invasive imaging procedure. It is painless, cost-effective and easy to use. Invasive procedures like needle biopsies can be done with the help of ultrasound as a guiding tool. There are no known dangerous effects that stem from ultrasound imaging. Since it has limited viewing power from air or bone, other imaging techniques will come in handier for bone and lung viewing.

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