physics

Ultrasound energy

Ultrasound energy is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Ultrasound energy rather than just read about it. In short: Ultrasound energy, simply known as ultrasound, is a type of mechanical energy called sound characterized by vibrating or moving particles within a medium. Ultrasound is distinguished by vibrations with a frequency greater than 20,000 Hz, compared to audible sounds that humans typically hear with frequencies between 20 and 20,000 Hz.

Key takeaways

Ultrasound energy belongs to physics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Ultrasound energy to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Ultrasound energy from memory before moving on to harder problems.

Reference excerpt

Ultrasound energy, simply known as ultrasound, is a type of mechanical energy called sound characterized by vibrating or moving particles within a medium. Ultrasound is distinguished by vibrations with a frequency greater than 20,000 Hz, compared to audible sounds that humans typically hear with frequencies between 20 and 20,000 Hz. Ultrasound energy requires matter or a medium with particles to vibrate to conduct or propagate its energy. The energy generally travels through most mediums in the form of a wave in which particles are deformed or displaced by the energy then reestablished after the energy passes. Types of waves include shear, surface, and longitudinal waves with the latter being one of the most common used in biological applications. The characteristics of the traveling ultrasound energy greatly depend on the medium that it is traveling through. While ultrasound waves propagate through a medium, the amplitude of the wave is continually reduced or weakened with the distance it travels. This is known as attenuation and is due to the scattering or deflecting of energy signals as the wave propagates and the conversion of some of the energy to heat energy within the medium. A medium that changes the mechanical energy from the vibrations of the ultrasound energy into thermal or heat energy is called viscoelastic. The properties of ultrasound waves traveling through the medium of biological tissues has been extensively studied in recent years and implemented into many important medical tools.

Common medical applications of ultrasound energy

Diagnostic imaging As stated above, properties of ultrasound energy traveling through biological tissues has been extensively studied in recent years. The attenuation due to scattering of energy in different tissues can be measured by a device called a transducer. Recorded information from transducers such as the relationship to the site of origin and intensity of the signal can then be put together to form images of what lies inside the target tissues. Higher frequency ultrasound waves generally produce higher resolution images, but attenuation also increases as frequency increases which restricts imaging depth. Consequently, the best frequency has been determined for each type of diagnostic test and body tissue. Some of the more common ultrasound tests include A-scans, M-scans, B-scans, and Doppler techniques. These test produce images ranging from one-dimensional images to moving, real-time two –dimensional images that can often be seen immediately on a screen. The advent of ultrasound technology has completely changed the medical diagnostic field due to its non-invasive characteristic. Medical professionals can now observe tissues within the body without having to physically enter the body. This reduces the amount of invasive and risky diagnostic procedures and increases the chances of a correct diagnosis. Some common medical imaging procedures include:

Sonogram - Ultrasound images of an unborn fetus are used to check for proper development and other characteristics. Tumor/cancer diagnosis - Images can be used to examine suspicious masses found inside the body and determine if other treatment is necessary. Blood flow - Images can be used to examine the flow of blood through specific vessels and examine if there is any blockage or abnormalities. Internal organs - Images can be used to look at the physical shape and movements of internal organs to insure they are working properly. Intravascular decompression bubbles

Oncology treatment One characteristic of ultrasound previously discussed is that of attenuation of an ultrasound signal partly due to the conversion of mechanical wave energy to thermal energy. Researchers and doctors have made medical applications to harness this heat conversion and use it in successful medical procedures. Ultrasound energy is a form of therapy being studied as an anticancer treatment. Intensified ultrasound energy can be directed at cancer cells to heat them and kill them. Recent testing has shown that ultrasound can increase the effectiveness of cancer treatments such as chemotherapy and radiation therapy. This procedure is known as heat or hyperthermia therapy. By using the converted heat energy that ultrasound provides, specific diseased tissues can be heated often to temperatures around 41° to 45 °C. This increase in temperature has been linked to improved effectiveness of cancer treatment due to dilation of blood vessels and increased oxygen presence in affected tissues. Another new treatment called high intensity focused ultrasound (HIFU) takes advantage of the thermal energy characteristics of ultrasound. HIFU uses an ultrasound device that is able to precisely focus ultrasound waves at a target tissue or specific group of cells. At the focus of this ultrasound energy, the temperature can reach excesses of 80 °C which results in nearly spontaneous coagulative necrosis or cell death without harming neighboring cells. This treatment greatly expands the ability of doctors to be able to destroy cancer cells noninvasively. Currently, many test are being carried out to determine the effectiveness of the treatment on different tissues, but testing has already shown promising results in the field of prostate cancer.

Phacoemulsification

Phacoemulsification is a cataract surgery method in which the internal lens of the eye which has developed a cataract is emulsified with the tip of an ultrasonic handpiece and aspirated from the eye. Aspirated fluids are replaced with irrigation of balanced salt solution to maintain the volume of the anterior chamber during the procedure. This procedure minimises the incision size and reduces the recovery time and risk of surgery induced astigmatism. It is best suited to relatively soft cataracts, where the ultrasonic energy required is moderate.

References

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Worked examples

Example 1 — a first encounter with Ultrasound energy

Start with the simplest possible case. Write down what Ultrasound energy claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Ultrasound energy before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Ultrasound energy ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Ultrasound energy

In research: Ultrasound energy appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Ultrasound energy in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Ultrasound energy is common in secondary-school and first-year university syllabi. It links to neighbouring topics Medical ultrasonography, so understanding it makes those chapters shorter.
In everyday life: Look for Ultrasound energy outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Ultrasound energy in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Ultrasound energy means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Ultrasound energy out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Ultrasound energy in simple terms?

Why does Ultrasound energy matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Ultrasound energy?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Ultrasound energy.