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US Modalities
| Question | Answer |
|---|---|
| What is US frequency defined as? | greater than 20,000 cycles per second |
| Therapeutic US typically has a frequency between what? | .7 and 3.3 MHz |
| What is another name for transducer | Soundhead |
| the amount of acoustic energy per unit of time is expressed in what? | watts |
| Intensity is measured by? | W/cm2 |
| continuous | 100% |
| 1:1 | 50% |
| 1:2 | 33% |
| 1:3 | 25% |
| 1:4 | 20% |
| 1:4 duty cycle is | generally 2m on 8m off |
| frequency is expressed how? | cycles per second |
| T or F: 1MHz penetrates deeper than 3.3MHz | T |
| What is attenuation? | the decrease in US intensity as the wave travels through tissue |
| T or F: increasing protein content decreases absorption? | F |
| What is the percentage of reflection in the air | 100% |
| Almost all US is reflected where? | the metal/air interface |
| When refraction occurs the US enters the tissue at one angle and continues at? | A different angle |
| Gas filled or vapor bubbles caused by US | caviataion |