MSK Diag Mgt 7220 Exam II - ultrasound & phonophoresis
frequency range for therapeutic ultrasound
.7 to 3.3 MHz
therapeutic range of US intensity
.25 to 2.0 W/cm2
beam non uniformity ratio
spatial peak intensity: spatial average intensity
dissipation of energy is
if target tissue is superficial choose _____ MHz frequency. If target tissue is deep choose ____ MHz frequency.
3 Hz; 1 Hz
rate of heating will be (higher/lower) with 1 MHz or 3 MHz.
3 MHz will heat faster
typical beam non uniformity ration
between 2:1 and 6:1
why does absorption increase with increased frequency?
higher frequency - the molecules move faster against friction and heat is produced.
absorption is highest in tissues with ______ content like _____
high protein; ligaments, tendons, fascia, joint capsules and scar tissue
absorption is lower in tissues with _____ water content like blood and fat
if you want heat tx, you choose continuous mode or pulsed mode?
how do you calculate duty cycle?
if US is on for 2 ms in a 8 ms pulse period, what is the duty cycle?
on time / (on time = off time) x 100%
max depth of absorption for therapeutic ultrasound (range for 1.0 MHz)
which frequency might you use on the patellar tendon, MCL, or brachialis insertion? How deep are you penetrating?
.8 - 1.6 cm
which frequency might you use on the rotator cuff, vastus intermedius and gastroc? how deep are you penetrating?
improved circulation, extensibility of collagen, and collagen synthesis are thermal or non thermal effects?
calcium deposit reabsorption, cell proliferation, and angiogenesis are thermal or non thermal effects?
Increased NCV, decreased spasm, and pain control are thermal or non thermal effects
diffusional changes across cell membrane which alter cellular activity and function (cavitation) are associated with thermal or non thermal US
mixed research shows that edema resolution, tissue regeneration, and fracture healing may be associated with thermal or non thermal effects of US
increased mast cell degranulation, increased protein synthesis by fibroblasts, and increased intracellular Ca are associated with thermal or non thermal effects of US
guidelines for fracture healing with US
.15 W/cm^2, 1.5 MHz, 20% duty cycle, 15-20 minutes daily
contraindications - do not apply US to these areas
over the eye, over the heart, over the pregnant uterus, over tests, over cancer, over a pacemaker
contraindications of US
decreased sensation to heat and pain
decreased circulation or vascular insufficiency
over s/p laminectomy
growth plates in children
how large should the treatment area be compared to the transducer?
the treatment area should be 1.5-2 times the size of the transducer
internal effects of stationary US head
platelet aggregation, cavitations, venous endothelial damage, stasis of blood
what needs to be documented when administering US?
who and what machine
what area - size and anatomical location
intensity and duration
technique and coupling medium
any precautions or contraindications
what is non contact low frequency ultrasound used for?
cleansing and debriding for wound healing