Exam 2 Flashcards
What type of heat transfer is US
Conversion
3 types of US
Diagnostic
Therapeutic
Surgical
How deep does therapeutic US go
2-5 cm
What is US most commonly used for?
deep heating and biophysical effects
what type of tissue does US travel best through
Dense material
Ligaments, tendons, joint capsule, scar tissue etc.
What does frequency of US determine
depth, wavelength and temperature
1 MHz
goes deeper 2-5 cm
slower absorption
long wave length
3.3 MHz
shower wavelength
quick absorption
reaches only 2 cm
What is the effective radiating area
The inner portion that propagates sound
What is the beam non-uniformity ratio with US
the middle of transducer has the highest peak and the outside has less
Continuous mode for US
100% duty cycle
sound energy is constant
thermal effects
Pulsed Mode for US
10, 20, or 50% duty cycle
minimizes thermal effects
Thermal effects of US
increase metabolic rate for tissue healing
elevate motor and sensory nerve conduction (pain reduction)
Reduces spasm
Vasodilation
increased ROM
what is ultrasound not ideal for heating?
Muscles
how to increase thermal effects of ultrasound
Increase duration and/or increase intensity 1.5 watts/cm
non-thermal effects of US
increased skin and cell permeability
increased cell degranulation
increase phagocytic activity
increased rate of protein synthesis by fibroblast
Enhances wound healing
Clinical applications of non-thermal US
Edema
pain control
wound healing
Trigger points
Documentation of US
Frequency
Intensity
Duty cycle
time
location
transmission medium
Pt tolerance
results
phonophoresis
delivery of medicated lotion via ultrasound
“upgraded ultrasound and downgraded iontophoresis”
What level does TENS and Iontophoresis reach
sensory level
Contraindications for electrical modalities
cardiac pacemakers/ electronic implants
over carotid sinus
near venous or arterial thrombosis
over areas of indwelling phrenic nerve or urinary bladder stimulators
Direct current
continuous unidirectional flow of electrons
alternating current
uninterrupted bilateral flow of electrons
pulsed current
when electron flow is interrupted for milliseconds or microseconds
can be either AC or DC