Therapeutic Ultrasound: Principles & Mechanisms

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Questions and Answers

Which of the following best describes the primary mechanism by which therapeutic ultrasound waves transfer energy to tissues?

Chemical reactions induced by the ultrasound waves.
Direct conversion of electrical energy to thermal energy within the tissue.
Mechanical vibration of molecules, transmitting energy to adjacent molecules. (correct)
Stimulation of cellular metabolism through electromagnetic radiation.

Why is a coupling agent, such as gel, essential when applying therapeutic ultrasound?

To protect the skin from direct contact with the applicator.
To enhance the visual clarity of the treatment area.
To eliminate air between the applicator and skin, thereby improving wave transmission. (correct)
To reduce the risk of allergic reaction to the ultrasound waves.

How does the Beam Non-uniformity Ratio (BNR) affect the application of therapeutic ultrasound?

It measures the depth of penetration of the ultrasound waves.
It calculates the total energy absorbed by the tissue during treatment.
It determines the frequency range that can be used for treatment.
It indicates the uniformity of the ultrasound beam, with lower ratios being more desirable. (correct)

What is the primary advantage of using ultrasound for thermal effects compared to other heating modalities?

Ultrasound can selectively heat deeper tissues high in collagen without significantly increasing temperature in skin or fat. (D) Signup and view all the answers

Which statement best describes the 'stable cavitation' effect of non-thermal ultrasound?

Expansion and contraction of gas-filled bubbles, providing therapeutic benefits. (B) Signup and view all the answers

How should the ultrasound sound head be moved during treatment and why?

Continuously, to avoid hot spots and tissue damage. (D) Signup and view all the answers

A physical therapist is determining the appropriate ultrasound frequency for a patient with a muscle strain located approximately 2 cm deep. Which frequency is most appropriate and why?

3 MHz because it penetrates more superficially. (A) Signup and view all the answers

What factors should be considered when determining the appropriate duration of ultrasound treatment?

Treatment area size, ultrasound unit settings, and the condition being treated. (B) Signup and view all the answers

Which of the following is the MOST accurate way to calculate ultrasound dosage?

Intensity (W/cm²) × sound head area (cm²) × time (seconds) = Joules (Watt-seconds). (C) Signup and view all the answers

What is the primary reason why the evidence supporting phonophoresis is weak?

Other more effective treatment options treat pain and inflammation. (B) Signup and view all the answers

Which of the following is a contraindication for continuous ultrasound but may be acceptable with pulsed ultrasound?

Active bone growth at the epiphysis. (D) Signup and view all the answers

Why is it important to exercise caution when using ultrasound over metal implants?

Metal absorbs ultrasound waves and can overheat, potentially burning surrounding tissues. (D) Signup and view all the answers

When is it MOST appropriate to apply stretching exercises in conjunction with ultrasound therapy?

During the last few minutes of ultrasound treatment or immediately after heating. (A) Signup and view all the answers

What is the rationale behind using the lowest possible intensity of ultrasound that achieves the desired therapeutic effect?

To minimize the risk of unstable cavitation. (D) Signup and view all the answers

How can the ERA be used most effectively to guide treatment decisions?

To determine the appropriate size of the treatment area. (C) Signup and view all the answers

Which of the following best describes the duty cycle in pulsed ultrasound?

The percentage of time that ultrasound energy is being delivered. (C) Signup and view all the answers

What is the primary clinical implication of understanding that patients can have widely variable temperature responses to the same ultrasound application?

It is crucial to individualize treatment and monitor patient response closely. (C) Signup and view all the answers

Which of the following statements reflects an evidence-based approach to using therapeutic ultrasound?

Integrate ultrasound into a comprehensive plan, considering the limitations of the evidence. (B) Signup and view all the answers

Which of the following conditions has the strongest evidence supporting the therapeutic effectiveness of ultrasound?

Myofascial pain (C) Signup and view all the answers

Why is constant motion of the ultrasound applicator during treatment essential?

To prevent the formation of standing waves. (C) Signup and view all the answers

How does ultrasound's frequency relate to its depth of penetration in tissues?

Lower frequency penetrates deeper. (C) Signup and view all the answers

What is the significance of raising tissue temperature to 40-45°C for a minimum of five minutes when using thermal ultrasound?

It is necessary for increasing collagen extensibility. (D) Signup and view all the answers

Which non-thermal effect of ultrasound alters cell membrane permeability, potentially accelerating healing?

Acoustic streaming (A) Signup and view all the answers

When explaining ultrasound to a patient, what key point should be included about the scientific evidence supporting its effectiveness?

The evidence is mixed, and its effectiveness can vary. (C) Signup and view all the answers

Which of the following terms describes the decrease in ultrasound intensity as it travels through tissues?

Attenuation (C) Signup and view all the answers

Which statement correctly links a specific indication with the appropriate type of ultrasound?

Pulsed mode for acute inflammation to minimize thermal effects. (B) Signup and view all the answers

Which scenario represents an inappropriate application of ultrasound, considering established contraindications?

Continuous ultrasound applied directly over an area of suspected malignancy. (C) Signup and view all the answers

A patient reports feeling no warmth during continuous ultrasound treatment at standard parameters. What is the most likely explanation?

The dosage is inadequate to produce thermal effects. (B) Signup and view all the answers

If standing waves develop during ultrasound application, what potential risk does this pose to the patient?

Hot spots and discomfort or tissue damage. (A) Signup and view all the answers

Which of the following is NOT a thermal effect of ultrasound?

Cavitation. (A) Signup and view all the answers

According to the information provided, what is the recommended speed for moving the ultrasound sound head during treatment?

Speed is less important than keeping it moving. (A) Signup and view all the answers

How would you explain the purpose of using ultrasound to a patient who has muscle spasms?

Ultrasound uses high-frequency sound waves to reduce pain, improve healing, and decrease muscle spasm. (B) Signup and view all the answers

The Spatial Average Intensity (SAI) is calculated by:

Dividing the power output by the ERA. (B) Signup and view all the answers

A patient has a cemented hip implant. Which precaution should the therapist take when applying ultrasound?

Avoid treating over cemented implants. (D) Signup and view all the answers

A physical therapist is treating a patient with carpal tunnel syndrome. What is the BEST choice of ultrasound mode and rationale?

Continuous mode, to increase tissue temperature and blood flow. (D) Signup and view all the answers

A Physical Therapist is treating a patient’s quadriceps muscle strain with ultrasound. The muscle strain is 5 cm deep. Which frequency would be BEST?

1 MHz (A) Signup and view all the answers

Why is continuous movement of the ultrasound applicator crucial during treatment?

To prevent the development of standing waves and hot spots. (B) Signup and view all the answers

A physical therapist is using continuous ultrasound to increase tissue temperature. What is the MINIMUM temperature increase required to achieve therapeutic effects, such as increased collagen extensibility?

4-degrees Celsius or greater (A) Signup and view all the answers

What is the BEST method for applying ultrasound to a body part with irregular surfaces, such as the hand?

Immersion in water. (C) Signup and view all the answers

Which of the following is considered a non-thermal effect of ultrasound?

Cavitation. (C) Signup and view all the answers

A patient with myofascial pain is being treated with ultrasound. What is the MOST important guideline to follow regarding the radiating waves?

Keeping the waves perpendicular to the skin. (A) Signup and view all the answers

A patient is being treated with pulsed ultrasound. What is the primary therapeutic goal when using this mode?

To achieve non-thermal effects for tissue healing. (A) Signup and view all the answers

When using ultrasound in conjunction with stretching exercises, when is the OPTIMAL time to perform the stretching?

During the last few minutes of the treatment or immediately after. (D) Signup and view all the answers

What is the rationale behind using the lowest intensity of ultrasound that yields a therapeutic effect?

To minimize the risk of tissue damage. (A) Signup and view all the answers

Which of the following is a precaution for using continuous ultrasound?

Over metal implants. (D) Signup and view all the answers

A physical therapist is documenting an ultrasound treatment. Which of the following pieces of information is MOST important to include?

The ultrasound parameters, patient position, and patient response. (A) Signup and view all the answers

Flashcards

Therapeutic Ultrasound

High frequency mechanical waves delivered using acoustic or sound energy. Produces mechanical action by vibrating molecules.

Ultrasound Transmission

Efficient transmission in tissues of higher densities. Requires a coupling agent to eliminate air between the applicator and skin.

Ultrasound Wave Type

Longitudinal transmission via compressions (increased density) and rarefactions (decreased density) of molecules.