ultrasound Flashcards
what is ultrasound
ultrasound is high-frequency sound waves above 20,000hrtz
what frequency is ultrasound
1- 3 Mega Hearts
what is the piezoelctric effect
electrical currents cause the crystal within the transducer to expand and compress, this creates movemtn at the transducer head producing ultrasound waves
what structures absorb sound waves better
ones with lower water and higher protien content
what frequency is used for superifical structures
3Mhz
whta frquency is good for deep structures
1Mhz
define continuous ultrasound
ultrasound inetnsity remains consistent over time, provides a thermal effect that could promote blood flow
defien pulsed ultrasound
ultrasound is in intervals so overall output is lower and there is less thermal effect
when should you use pulsed ultrasound
if the injury is at the acute stage or if a inflamatory repsonse is still prresent
when should you use continuous ultrasound
when the injury is at a subacute or chronic phase
how long dshould treatment be applied
1 minute x size of heads needed (1 or) x pulse ratio
shocase the duty cycles of pulsed ratios modes
acute is1:4 or 20%, sub actute is 1:2 or 1:3, pulsed ratio is 1:1 or 50%
what are the general contraindications for ultrasound therapy?
pregnancy, cancer/malignancy, bone damage, psoriasis, haemophilia, neoplastic tissue, deep vein thrombosis, atherscorlosis, recent x-rays
what is haemophilia
trouble blood clotting that leads to excessive blood clots
what is psoriasis
flaking itchy inflamed skin
what is neoplastic tissue
tissue that has rapidly produced causing a lump or tumor
what is deep vein thrombosis
blood clots within the veins or arteries
what is atherscorlosis
build-up of fats or cholesterol in the arteries
what are the three theoretical benefits of ultrasound
cavitations, acoustic streaming,
what are the precautions for ultrasound
no use over epiphyseal plates, care over bony areas, and start with lowest possible intensity
what parts of the body should not be applied with
eyes, genitals, cardiac area (if there is a heart problem present), pacemaker, the brain/spinal cord, active epiphyseal plates
what is the aim of therapeutic ultrasound
reduce pain and improve tissue healing
explain cavitations and their benefits
bubbles form in the gaps in tissues and oscillate in the sound waves causing cell excitability to increase
explain acoustic streaming and its benefits
sound waves cause the liquid around the tissue to vibrate, this alters the tissues cell permeability increasing diffusion rates, along with cavitations increase cell activity
