what is temporal average?
- average intensity across entire pulse period
- includes dead zone
what is pulse average?
- average intensity across entire pulse duration
- does not include include dead zone
what compination of bioeffects in most commonly used?
SPTA
what is the highest combination of bioeffects?
SPTP
what is the lowest temporal average?
SATA
bioefefcts and safety lowest to highest combinations?
- SPTP
- SATP
- SPPA
- SAPA
- SPTA
- SATA
Organizations have set standards that ultrasound providers are to adhere to what are they (2)?
FDA
AIUM
what is AIUM?
“No adverse effects have been observed for an unfocused beam having a SPTA below 100mW/cm2, and focused beam SPTA below 1 W/cm2”
FDA SPTA?
720 mW/cm2 (Upper limit)
ferent kinds of ultrasound have different intensities- order from weakest to strongest
- 2D
- M-mode
- colour
- PW
Thermal Index?
- measure how much the particular soubd is heating up the tissue
AIUM Standard: TIS?
<2
- 2 degrees max
thermal index- AIUM standard: TIB?
<1.5
Cavitation (2 types)?
Production and modification/behaviour of bubbles in a liquid
Stable Cavitation?
- oscillating bubbles (bigger and smaller)
- produce waves
- shear forces on nearby cells and organelles
Transient Cavitation examples?
- shock waves
- local high temperature changes
- light emission
Mechanical Index: AIUM Standard?
< 1.9 (0.4-1.9)
Peak rarefactional pressure is proportional to?
MI
what tissue will have a higher risk of cavitation?
gas containing tissues
