Ultrasound Physics - 22\bioeffects

Front 1

Where does most energy produced by the transducer remain?

Back 1

In the body

Front 2

What instrument measures acoustic pressure at specific locations within the sound beam?

Back 2

Hydrophone
Microprobe

Front 3

What instrument is made of a small hypodermic needle with a tiny piece of PZT at its tip; attached to an oscilloscope at the other end

Back 3

Hydrophone
Microprobe

Front 4

A hydrophone measures what three variables?

Back 4

Period
PRP
PRF

Front 5

This instrument allows us to view the shape of a sound beam in a medium; it is based on acousto-optics or the interaction of sound and light

Back 5

Schlieren

Front 6

This instrument measures the total power in a sound beam through the process of absorption; power is calculated by measuring the temperature rise and the time of heating

Back 6

Calorimeter

Front 7

This instrument measures the sound beam's power at particular locations in the beam

Back 7

Thermocouple

Front 8

What is the difference between a calorimeter and a thermocouple?

Back 8

A thermocouple measures power at particular locations in the beam
A calorimeter measures power of the entire beam

Front 9

This instrument changes color with temperature

Back 9

Liquid Crystals

Front 10

What is it called when a beam's small but measurable force is absorbed by or reflected by the target, the target acts as an extremely sensitive postal scale

Back 10

Radiation Force

Front 11

When it comes to clinical ultrasound, the ___ must outweigh the ___

Back 11

Benefits
Risk

Front 12

Even after years of clinical use and study, there is no confirmation of ___ resulting from ultrasound

Back 12

Harm

Front 13

T/F: Extremely high ultrasound intensities can damage biologic tissues

Back 13

T

Front 14

T/F: Low intensity ultrasound has no known bioeffects

Back 14

T

Front 15

T/F: there are known cases of diagnostic imaging at standard intensities resulting in biological effects or tissue injury

Back 15

F

Front 16

The science of identifying and measuring the characteristics of an ultrasound beam that are relevant to its potential for producing biological effects, is called what?

Back 16

Dosimetry

Front 17

Research performed within the living body is called what?

Back 17

In Vivo

Front 18

Research performed outside the living body is called what

Back 18

In Vitro

Front 19

According to the AIUM, ___ bioeffects research is important

Back 19

In Vitro

Front 20

According to the AIUM, in vitro bioeffects are ___ even though they may not apply to the clinical setting

Back 20

Real

Front 21

According to the AIUM, in vitro bioeffects which claim direct clinical significance (without in vivo validation) should be viewed with ___

Back 21

Caution

Front 22

NEMA stands for what?

Back 22

National Electrical Managers Association

Front 23

This study technique searches for a relationship between cause and effect

Back 23

Mechanistic Approach

Front 24

This study technique searches for a relationship between exposure and response

Back 24

Empirical Approach

Front 25

Both study techniques have merit; strongest conclusions are made when ___

Back 25

Conclusions of Both Approaches Agree

Front 26

This mechanism proposes that bioeffects result from tissue temperature elevation

Back 26

Thermal Mechanism

Front 27

This calculated number, is a useful predictor of maximum temperature increase under most clinically relevant conditions

Back 27

Thermal Index (TI)

Front 28

The soft tissue thermal index assumes sound is traveling in soft tissue; what is it called?

Back 28

TIS

Front 29

The bone thermal index assumes that bone is at or near the beam focus; what is it called?

Back 29

TIB

Front 30

The cranial bone thermal index assumes that cranial bone is in the sound beam's near field; what is it called?

Back 30

TIC

Front 31

This mechanism is the interaction of sound waves with microscopic, stabilized gas bubbles in the tissues; it also describes the creation of gaseous nuclei from dissolved gasses in a fluid

Back 31

Cavitation Mechanism

Front 32

At lower mechanical index levels, gaseous nuclei oscillate (expand & contract) but do not burst, absorbing much of the energy

Back 32

Stable Cavitation

Front 33

At higher mechanical index levels, gaseous nuclei burst producing high temperatures and high pressure shock waves

Back 33

Transient Cavitation
Inertial/Normal Cavitation

Front 34

This is a calculated number related to the likelihood of harmful bioeffects from cavitation and is the best indicator of these effects

Back 34

Mechanical Index

Front 35

A bioeffects report claims that OB scanning may be harmful to a particular group of patients. What should be the response of the medical community?
A. perform the exams on all patients when the benefits are outweighed by the risks
B. stop all diagnostic exams
C. ignore the report
D. halt all exams on this patient group
E. perform exams on all patients when the benefits outweigh the risks

Back 35

E

Front 36

T/F: there are no bioeffects associated with ultrasound

Back 36

F