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Ultrasound 10cm 2

Ultrasound 10cm 2. Ultrasound (US) . Therapeutic ultrasound Uses acoustic energy, delivered at high frequencies for therapeutic purposes Electrical current creates a mechanical vibration in a crystalline material housed in a “head” of the unit

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Ultrasound 10cm 2

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  1. Ultrasound 10cm2

  2. Ultrasound (US) • Therapeutic ultrasound • Uses acoustic energy, delivered at high frequencies for therapeutic purposes • Electrical current creates a mechanical vibration in a crystalline material housed in a “head” of the unit • Vibration of this material produces acoustic energy • Energy emitted from the head travels through tissues and is absorbed • Sound energy used for diagnostic imaging differs in amplitude and pulse characteristics

  3. Ultrasound (US) • Crystal quality and size: BNR and ERA • Effective radiating area (ERA)—the area that receives at least 5% of the peak sound energy • Beam nonuniformity ratio (BNR)—ratio between peak amplitude and the average amplitude of the ultrasound beam across the ERA • The lower the BNR, the more uniform the intensity of the sound wave • Lower BNR minimizes the risk of “hot spots” and allows for higher doses to be applied • Acceptable BNR range is between 2 and 6 (must be listed on all units)

  4. Ultrasound (US) • Conducting media • Substances used to conduct US • US gel and gel pads—effective conductors • Mineral oil—poor • Lotions—poor • Water—may attenuate as much as 66% of sound waves; not very good

  5. Ultrasound (US) • Parameters of treatment with US • Amplitude—clinician controlled • Sound energy emitted by crystal measured in watts (W) • Dose of sound energy delivered is based on amount of energy being emitted divided by the radiating area of the crystal, which is measured in square centimeters • US dose is measured in W/cm2 • Duty cycle • Ratio of “on” time to “off” time (pulsed) • No interruption: 100% duty cycle or continuous US

  6. Ultrasound (US) • Duration of treatment • Frequency • Affects the depth at which greatest amount of US energy is absorbed • Typically either 1 MHz (deeper) or 3 MHz (superficial) • Most older units have a single fixed frequency of 1 MHz, but those offering more than one are now common

  7. Ultrasound (US) • Sound energy absorption in tissues • Tissues with greater protein density have a higher rate of US absorption • Tendon, ligament, and muscle tissue • Superficial bones and nerves absorb the most energy • Tissues with higher water content have a lower absorption rate (skin and adipose tissue) • US at a higher frequency (3 MHz) is absorbed more rapidly than at a lower frequency (1 MHz)

  8. Ultrasound (US) • Thermal effects of US • Potential to increase local blood flow • Increases in collagen elasticity • Analgesic and antispasmotic responses not as great as those following cryotherapy, superficial heating, and TENS

  9. Ultrasound (US) • Tissue heating and cool-down • Duty cycle • Continuous US results in therapeutically beneficial amounts of tissue heating • Total energy delivered during pulsed US is less at the same intensity and duration • Dose • The greater the dose of sound energy, the greater the amount of energy delivered to the tissues • With continuous US, higher dose results in greater tissue heating in less time • Treatment time • Interaction among frequency, dose, and time required to increase tissue temperature • Longer applications needed when lower intensities of US are used

  10. Ultrasound (US) • Treatment area • When larger areas are treated, the amount of acoustic energy reaching any single area is decreased • Best recommendation suggests treatment area of two to three times the ERA • Sound head movement • Moving sound head slowly prevents hot spots and helps to maintain good surface contact • Rapid, sloppy movement of the sound head with infrequent surface contact decreases thermal response • Thermal response to US is short-lived • Superficial tissues cool more rapidly • Stretching or manual therapies should be performed immediately for benefits of US to be realized

  11. Interferential • Is used to Reducing pain • Uses 4 electrodes to deliver 2 currents, one current w/ a constant frequency and the other current w/ a variable frequency • Frequency of over 4000 Hz = comfortable & able to pass through the skin surface • Where they cross is called the “beat” • General accepted range is 80 to 150 Hz, w/ low 0 to 10Hz • Low range is to increase local blood circulation • High range for pain relief

  12. Premodulated (Bi-Polar) Therapy • Reduces pain and increases R.O.M. • Used for treating small areas where 4 electrodes cannot be placed • Uses one output jack w/ a waveform identical to interferential current while only using 2 electrodes

  13. Russian Stimulation • The output of this is a 2,500 Hz sinusoidal wave. • Russian stimulation currents produce strong muscle contractions. • Allows the user to choose muscle contraction/relaxation cycle from a preset option of 10/10, 10/20, 10/30, 10/40 & 10/50 or user-defined or continuous

  14. Russian Stimulation

  15. Ultrasound 2cm2

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