Ultrasound
Door Kayla Padilla
1. Frequency of Wave Transmission
1.1. Frequency
1.2. The higher the frequency of the sound waves, the less the sound will diverge producing a beam of sound
1.2.1. Higher frequency sound waves are absorbed in the more superficial tissues
1.3. The lower the frequency, the greater the depth of penetration
1.4. Velocity
1.4.1. Propagated through the conducting medium and is directly related to density
1.4.2. Denser and more rigid materials have a higher velocity of transmission
1.5. Attenuation
1.5.1. Decrease in energy intensity
1.5.2. Decrease due to either absorption of energy by tissues or dispersion and scattering of the sound wave that results from refection or refraction
1.5.3. Standing Wave (Hot Spot)
1.5.3.1. The intensity of the energy meets new energy being transmitted
2. Thermal Effects
2.1. An increase in the extensibility of collagen fibers found in tendons and joint capsules
2.2. Decrease in joint stiffness
2.3. Reduction of muscle spasm
2.4. Modulation of pain
2.5. Increased blood flow
2.6. Mild inflammatory response that may help in the resolution of chronic inflammation
3. Phonophoresis
3.1. Must be prescribed by a physician
3.2. Medication can be delivered, painless and noninvasive
3.2.1. Anti-inflammatories
3.2.1.1. Hydrocortisone
3.2.1.2. Cortisol
3.2.1.3. Dexamethasone
3.3. Typically either 1% or 10% hydrocortisone cream is used in treatments along with thermal ultrasound
4. 1 MHz = Targets deeper tissue
4.1. 3 MHz = Targets superficial tissue
5. Transverse Waves
5.1. Energy travels in soft tissue along the direction in which wave travels
5.2. Occurs only in bone
5.3. Can only travel in solids
6. Longitudinal Waves
6.1. Molecules are displaced in a direction perpendicular to the direction in which the ultrasound wave is moving
6.2. Occurs in soft tissues
7. Move through tissue in a series of compressions and rarefactions
8. Piezolelectric Effect
8.1. The crystal expands and contracts when a biphasic current is generated at the same frequency as the crystal resonance
8.2. Effective Radiating Area
8.2.1. The total area of the surface of the transducer that actually produces the sound-wave