Ultrasound Physics

Hydrophone aka?

a small hypodermic needle with a tiny piece of piezoelectric material attacfhed to its end. a wire connects the PZT crystal to an oscilloscope

a hydrophone voltage relates to ______ of the sound beam 

hydrophones measure accoustic pressure at _____ _______ with the sound beam

by moving the hydrophone to many locations one can determine the sound beams what?

What ultrasound variables can be determined by a hydrophone?

What output measurements and relationships can be determined by a calibrated hydrophone?

what is the special quality of the hydrophone that is constructed from a very thin membrane of PZT plastic?

what is the measurable force created by transducers that relates to the power of a beam

a shadowing system that allows us to view the shape of a sound beam in a medium

the conversion of sound energy to heat

3 devices used to measure heat in US

measures the total power in a sound beam through absorption

a tiny electronic thermometer it is inserted into the sound beam and the temperature is measured at a particular location. the temp rise is related to the sound beams power 

difference between calorimeter and a thermocouple 

this provides insight into the shape and strength of a sound beam by changing color with temperature fluctuations 

type of relationship where the benefits must outweigh the risks

the science of identifying and measuring the characteristics of an US beam that are relevant to its potential for producing biological effects

bioeffects research may be conducted in two broad areas

performed within the living body 

performed outside the living body

AIUM stands for

Summary of AIUM in vitro bioeffects

two techniques used to study bioeffects

begins as a proposal that a specific mechanism has the potential to produce bioeffects. based on that proposal, a theoretical analysisis performed to estimate the scope of the bioeffects at various exposure levels

which technique for studying bioeffects is concerned with cause and effect?

based on the acquisition and review of information from patients or animals exposed to ultrasound. seeks relationship between exposure and response

2 important bioeffects mechanisms

proposes that bioeffects result from tissue temperature elevation

a calculated number, it is a useful predictor of max temp increase under most clinically relevant conditions

TIS stands for 

TIB stands for 

TIC stands for 

does the thermal index have units

what temperature elevation would cause infertility in the testicles

no confirmed bioeffects have been confirmed for temperatures up to ___C for exposures less than 50 hours