What Is an Ultrasound Machine and How Does It Work

This entry was posted in Ultrasound Technology on by .

Ultrasound imaging is a term that almost everyone has heard at one point or another. Ultrasounds are one of the most common testing processes done for many causes in the medical field.

It is so common that you will find an ultrasound machine in every medical testing facility out there. However, while people know what is an ultrasound test, not many have an in-depth understanding of ultrasound machines and how they work.

Therefore, in this article, we will do a study of ultrasound machines in detail. We will go through the basics of these machines, how they work, and all the different types of ultrasound imaging machines out there.

What is Medical Ultrasound Imaging?

Medical Ultrasound is a process that uses sound waves for testing, diagnostic, or therapeutic reasons on a body’s internal organs. Based on the type of ultrasound used, the process may or may not result in images that can give a view and understanding of the body’s internal organs.

When medical ultrasound is used for making images of the body’s internal organs, the process is called medical ultrasound imaging. With medical ultrasound imaging, it is possible to identify the sources of inflammation or pain in the body.

Not only that, but medical ultrasound imaging is the most common testing method used on pregnant women to monitor the growth of a fetus inside the body.

The process is called medical ‘ultrasound’ because it utilizes ultrasound waves, which are very high-frequency sound waves. These sound waves cannot be heard or differentiated by human ears.

What is the difference between Ultrasound and Sonography?

Many people hear the term ‘sonography’ and consider it to be the same as ultrasound. While the two are quite similar, there is a little bit of difference that you should be aware of.

As we mentioned earlier, the medical ultrasound process can be diagnostic or therapeutic. When it is diagnostic, it is used as an imaging method. When it is therapeutic, no images are created.

Sonography is the term used for the imaging application of medical ultrasound technology. In simple terms, when medical ultrasound is used for diagnostic purposes and creates a picture, the process is called sonography.

As an added point of knowledge, the image that is created with medical ultrasound imaging is called a sonograph. The trained technician conducting the ultrasound imaging process is called a sonographer.

What is the difference between Ultrasound and CT Scan?

Computerized Tomography (CT) scan is another common medical imaging process used to identify ailments inside the body. However, this process is quite different from ultrasound imaging methods.

CT scans utilize X-rays to create a detailed image of the internal organs of the body. The X-ray tube is rotating to capture the images of different sections and slices of the tissues.

Since CT scans use X-rays, the process is radioactive and potentially harmful to the body to some extent. However, with ultrasound imaging, there is no radioactivity involved since the process uses sound waves instead of X-rays.

A Short History of Ultrasound

While the concept of ultrasound waves was established more than 100 years ago, the use of this science in medicine was adopted after the Second World War.

In 1947, Austrian physician Karl Dussik, with his physicist brother Friederick, used ultrasound to create a visualization of cerebral ventricles. This was a breakthrough in medical ultrasound imaging.

In 1949, George Ludwig utilized ultrasound imaging to analyze gallstones in soft tissue. This furthered the use of ultrasound waves in medical conditions.

Ultrasound imaging machines found their commercial applications in medicine in 1963 with Brightness Mode devices. These devices helped in creating a two-dimensional image of tissues and organs.

In the 80s, the ultrasound machines incorporated the principles of the Doppler effect to create color flow Doppler ultrasound which could even visualize blood flow.

When was the ultrasound machine invented?

The first medical ultrasound machine was developed in Glasgow by obstetrician Ian Donald and an engineer named Tom Brown. It was created in the year 1956, and further improved till it was perfected around 1959.

How Does an Ultrasound Machine Work?

The working principle behind medical ultrasound machines is similar to that of SONAR systems used in military and naval applications. Even bats use this principle to hunt their prey without relying on their sight.

Ultrasound machines rely on ultrasound waves, which are high-frequency sound waves. The machines emit these waves toward the body. These waves penetrate the outer organs such as skin and these waves bounce off the inner organs and tissues.

When they bounce and reflect, the reflected waves are recorded by the machine itself. The patterns of these reflections are used to create visualizations of the inner organs and tissues of the body.

Now you might be wondering how these waves penetrate some organs while reflecting off other organs. This phenomenon is decided by the wavelength/frequency of the wave used itself.

The frequency of ultrasound waves in medical applications is between 2 MHZ to 15 MHZ. The higher the frequency, the shorter the wavelength and the more is the attenuation. Therefore, by reducing the frequency and thereby reducing absorption, we can study deeper organs of the human body structures.

In the same way, superficial body structures can be studied by increasing the frequency of the ultrasound machine.

Here are the general frequencies of ultrasound-based on different body parts:

  • 2.5 MHZ: Present on the shortest frequency end of the ultrasound wave scale, this frequency is used to study the deep abdomen and for deep obstetric and gynecological applications.
  • 3.5 MHZ: This frequency moves the study from deep to general areas of the abdomen, obstetric, and gynecological applications.
  • 5 MHZ: This frequency is used to study the circulatory system, lymph nodes, pelvic areas, and breasts.
  • 7.5 MHZ: This frequency studies the breasts and the thyroid glands.
  • 10 MHZ: This frequency also studies the breasts and thyroid, and in addition is used to analyze the superficial veins and masses. It also applies to analyzing the musculoskeletal system of the body.
  • 15 MHZ: Based on the highest end of the frequency spectrum for medical imaging, this frequency also studies the musculoskeletal system and other superficial masses in the body.

What is Inside an Ultrasound Machine?

Ultrasound machines have evolved significantly over the past few decades. The machinery has become more compact and the resulting imagery has become more detailed, high-quality, and vivid.

This is because the parts inside the ultrasound machine are developed utilizing the technology of this day and age. Here is what you will find inside an ultrasound machine nowadays:


The transducer is the part that sends and receives the sound waves. If you have seen an ultrasound machine, the transducer is the little handheld probe that the technician uses. In early ultrasound machines, the job of sending and receiving these waves was done by two different units.

Central Processing Unit (CPU):

The Central Processing Unit is the mind behind an ultrasound machine. It coordinates the different signals emitted and received by the transducer and recreates the electrical signals in the form of a visual image on the monitor.


The display constantly shows the imagery that the transducer is scanning. With a display, the doctor can analyze the image for creating their diagnosis. It also enables the technician to navigate to the exact area that requires ultrasound imaging.

Control Knobs:

Control knobs enable the technician to adjust the settings for viewing a clear picture on the display. Control knobs generally also have the functionality of zooming the picture in and out.


Keyboards are used in ultrasound machines to enter patient data. By entering the patient data, every ultrasound record can be saved with the patient file. By storing patients’ ultrasounds with their data, it helps in maintaining accurate patient records on a digital medium.


The printer is used to create a hard copy of the ultrasound image. The hard copy can be utilized for examination by another doctor or to be put into a patient’s file for later use. Hard copies of ultrasound are also given to expecting parents as a picture of their child.

What are the Different Types of Ultrasound Machines?

In the early stages of its development, ultrasound technology was limited to creating blurry 2-dimensional images of the area of interest. However, with modern technology, the results that can now be obtained are fascinating.

Modern ultrasound machines are mainly of two types:

3D Ultrasound Imaging

3D ultrasound imaging machine captures different 2D images of the area of interest by the movement of the probe. These images are then superimposed by specialized software built into the machine, to create a 3D model of the tissue.

3D ultrasound imaging is often utilized for the detection of benign tumors and cancer in its early stages. Common areas for detection include the breasts, the colon, the prostate, and the rectum.

This type of ultrasound is also used to study the development of a fetus and detect any abnormalities in its growth, such as disproportionate limbs. It can even detect the blood flow in the blood vessels of the fetus.

Doppler Ultrasound

Doppler effect is based on the sound waves and their echo reflected from moving objects. When ultrasound machines incorporate this principle, the process becomes doppler ultrasound.

Doppler ultrasound is generally restricted to moving particles. Therefore, it is applied for studying the blood flow through the heart and the blood vessels in the body.

There are many different types of Doppler ultrasound machines out there. These include color doppler, power doppler, spectral Doppler, duplex Doppler, and continuous wave doppler. All these machines create 3D ultrasound images for the study of blood flow only.

What are the Uses of Ultrasound in Medicine?

There are several applications of ultrasound when it comes to medicine. Here is a list of various uses of ultrasound along with the body areas where the use applies:

Obstetrics and Gynaecology:

  • In the field of OBGYN, medical ultrasound is used to study the different stages of pregnancy. It can determine the size of the fetus along with its development and the due date.
  • Medical ultrasound depicts the number of fetuses, thereby predicting the possibility of multiple births. With medical ultrasound, the doctors can also define the sex of the baby.
  • Ultrasound can also provide any information on problems in pregnancy, such as the baby being implanted in the fallopian tubes instead of the uterus.
  • Even in the absence of pregnancy, ultrasound imaging is used to diagnose any probable tumors or cysts in the ovaries.


  • Ultrasound is the most common method to diagnose kidney stones.
  • It is also used for examining the flow of blood in the kidneys, as well as other kidney ailments.
  • Medical urology ultrasound machines can help in diagnosing prostate cancer at an early age, and prevent cancerous growth.


  • Cardiac ultrasound machines can detect if the heart is functioning healthily by checking the blood flow through the heart. It can also help in identifying any abnormalities in the heart.
  • If there are any blockages in the heart or the nearby arteries, they can be detected with ultrasound examinations.
  • It is also used to monitor the blood flow through the heart and blood vessels in the body.

Biopsy and Probing

  • Ultrasound is also used in biopsies and surgeries for guiding the probes and tools. Such biopsies are called ultrasound-guided biopsies.
  • In a transesophageal echocardiogram, an ultrasound probe inside the esophagus creates detailed images of the heart.
  • In transrectal ultrasound, an ultrasound probe is inserted in the male rectum to analyze the prostate.
  • A transvaginal ultrasound provides the capability to analyze the female uterus and ovaries with a probe.

Besides these applications, ultrasound is used to study a lot of other organs of the body. These include the eyes, pancreas, spleen, and gallbladder. For infants, ultrasound imaging can study the hips, brain, and spine.

Ultrasounds also apply to analyze the cause of pain or swelling in any general area of the body.

What are the Benefits of Using Ultrasound for Medical Imaging and Diagnosing?

There are more benefits to ultrasound imaging methods than any other medical imaging procedure. Some of these benefits are:

  • Medical ultrasound is one of the few medical non-invasive procedures. No needles are piercing the body, and no probe goes inside. The entire process takes place externally without insertions.
  • There is no pain at all associated with medical ultrasound imaging.
  • Methods like X-ray and CT scans have harmful radiation. However, ultrasound does not have any such radioactive rays. It uses sound waves that do not cause any radiation.
  • The method is cheap and easily available everywhere.
  • Ultrasound imaging is helpful in the visualization of soft tissues. These tissues do not show in X-rays. It is one of the only few methods that can analyze blood flow, that too without any insertions in the body.
  • Ultrasound is useful for sensitive conditions such as pregnancy, where care is required not to harm the fetus in any way.
  • Ultrasound imaging is a real-time imaging method. This provides faster results, and also makes the process useful for guided needle biopsies and fluid aspiration.

Are There Any Disadvantages of Ultrasound Procedure?

Ultrasound is one of the safest medical examination processes out there. There are no known disadvantages or risks associated with this process.

As mentioned earlier, there is no radiation used to create ultrasound images, so there is no threat of medical conditions caused due to radioactivity.

Additionally, being a non-invasive procedure, there is no risk of contamination or pain involved in the process.

How is a Typical Ultrasound Performed?

The process of performing a typical ultrasound is fairly simple. The patient sits on an examination table, usually facing upwards. The sonographer adjusts the table and the patient’s position based on the requirements of the particular ultrasound procedure.

Once the patient is in the correct position, the sonographer applies a water-based gel to the area that requires imaging. The gel reduces the air between the transducer and the skin, allowing for a clear image quality due to better wave travel.

Once the gel is applied, the sonographer moves the ultrasound probe all around that area of interest. The patient might feel a minor pressure from the ultrasound probe.

Do patients need to prepare for an ultrasound procedure?

Usually, an ultrasound exam requires minimal special preparation for better image quality and assessment. The particular preparation guideline is provided by the doctor or the sonographer beforehand, based on the area that requires the ultrasound.

General instructions for the patients are that they should wear loose-fit clothing and remove any jewelry or accessories from that area. In some situations, patients might be asked to wear a hospital gown for the procedure.

In some cases, the doctors commonly ask the patients not to eat or drink anything 12 hours before the ultrasound. The doctor might also recommend drinking a few glasses of water and avoiding urinating before the ultrasound so the ultrasound can analyze a full bladder.

How Much Do Ultrasound Machines Cost?

The price of ultrasound machines depends on the type of machine you buy and whether you get it new or used. It might surprise you to know that many of the ultrasound machines you see in a doctor’s office and emergency rooms are refurbished, as they can save a ton of money.

Prices of new ultrasound machines start at about $5000 for economical versions and can go up to $100,000 and over for flagship models. General ultrasound machines are on the cheaper end, while specialty machines with probes fall on the higher end of the scale.

The price of a used ultrasound machine can vary based on the machine quality and where you obtain it from.

USC Ultrasound is one of the most reliable suppliers when it comes to ultrasound machines. Many of the machines you see in high-end hospitals or small clinics are sourced from USC Ultrasound.

You can find both used as well as brand new ultrasound machines at USC Ultrasound. The best part is that if you cannot make a big one-time investment, USC Ultrasound also provides financing options for your next ultrasound equipment.


There are very few medical procedures that come without side effects, risks, or any pain involved. Ultrasound imaging is one of these few.

An ultrasound exam provides the ability to view internal tissues and organs in 3-D, without necessitating the use of probes and needles. This is why ultrasound machines are present in almost every medical environment.

If you have a clinic or a medical testing facility, getting a good ultrasound machine should be the first thing on your list. Browse through the range available at USC Ultrasound to get the best of these machines, along with other medical equipment that you require.