Ultrasound, Diathermy, lasers and lights Flashcards
The power per unit area of the should head, expressed in W/cm 2
intensity
is the number of compression rarefaction cycles per unit of time, expressed in cycles/ sec or Hz
Frequency
Increasing the frequency of the Ultrasound causes a decrease in it’s what?
in the depth of the penetration in the superficial tissues
the area of the transducer from which the Ultrasound energy radiates
ERA- effective radiating area
the proportion of the treatment time that the US is on
Duty Cycle
100% duty Cycle is on 100% of the time and it is the same as continuous US.
how do we decide frequency for US
frequency is based on depth of tissue
When would 3.3 MHz be used for US
when working on superficial tissue.
when would 1 MHz be used with US
when the tissue is deeper
The decrease in US intensity as US travels through tissue
Attenuation
attenuation is greatest in tissues with high collagen content
the property of being able to generate electricity
Piezoelectric
what are the thermal effects of Ultrasound
Acceleration of metabolic rate, reduction/control of pain and muscle spasms, increased circulations, increasing soft tissue extensibility
why can heating small areas of scar tissue in muscles absorb more Ultrasound?
b/c of increased collagen content
the speed at which the transducer is moved does not affect temperature….what does it affect?
it affects the location and hot spots
where is the highest temperature generally produced?
generally produced at bone interface
if the intensity if the ultrasound is to high what will the PT. complain of?
a deep ache from the overheating of the periosteum
what duty Cycle is used for non-thermal effects Aka pulsed ultrasound
20% duty Cycle
non-thermal effects of Ultrasound
increased intracellular calcium levels, increased skin cell membrane permeability, increase the release of histamines, promotion of macrophages responsiveness, facilitation of healing, enchantment of transdermal drug penetration
why can ultrasound be used for soft tissue contractures
Us can penetrate the depth of most joint capsules, tendons, and ligaments and it can be effective for heating those tissues before stretching
what are the parameters for US including the frequency, intensity and time
Frequency 1-3.3 depending on tissue depth 1-deep tissue 3.3- superficial Intensity .5-1.0 for superficial 1.5-2.0 for deep tissue
Time is 5-10 mins
What is phonophoresis with pulsed ultrasound
transcutaneous drug delivery.
trying to deliver meds through ultrasound cream
Contraindications for use of US
malignant tumors, pregnancy, joint cement or plastic components, pacemaker, thrombophlebitis
Precautions of US
acute inflammation, Epiphyseal plates, Fx, breast implants
Adverse effects of US
blood cell stasis due to collection of gas bubbles, possibilities of cross contamination and infection of PT’s
what stages of rehab would thermal US be applied
Sub-acute or chronic phases of healing
