US Physics Test

the routine, periodic evaluation of an US system to guarantee optimal image quality

What are some of the requirements of quality assurance?

What are some of the goals of quality assurance?

What are the two types of quality assurance devices?

What QA device is a fluid filled tank containing stainless steel pins or plastic strings?

The AIUM 100mm Test object is unable to evaluate?

What does the AIUM 100mm test object evaluate?

What does the AIUM 100mm test object determine?

What QA device is made of graphite-filled aqueous gel or urethane rubber materials?

What do tissue equivalent objects assess?

Tissue Equivalent phantoms have features similar to what?

What do Tissue Equivalent Phantoms evaluate?

What are the characteristics that make tissue equivalent phantoms similar to soft tissue?

This type of QA device will include structures that resemble soft tissue and are imbedded with cysts and solid masses.

What type of QA device includes a circulation pump which propels a fluid through vessels embedded in a tissue equivalent phantom?

What do doppler phantoms assess?

Doppler Phantoms may use what as movement?

Doppler phantoms can produce what type of movement?

What are the disadvantages of doppler phantoms?

Dopplar phantoms are helpful in determining what?

What QA device mimics soft tissue and measures the beams geometry perpendicular to the imaging plane?

What are alternative names for slice thickness phantom?

ability of a system to display low-level echoes

assessment of the weakest echo that is accurately displayed determined by setting the TGC flat, then increasing system gain from the minimum value to the gain when a deep rod is displayed

found at a higher gain, all the pins, solid masses, and cystic structures are accurately displayed and adjustments are made to output power, TGC, and amplification

the output power and amplification are set to the highest practical level, the depth of tissue-like texture is determined

results from the transducer ringing and the time it takes for the system to switch from transmit to receive, close to the transducer

Which transducers have a thinner dead zone?

What will help eliminate issues caused by the dead zone?

ability to place reflections in the proper position while imaging from different orientations

vertical depth calibration places objects correctly parallel to the sound beam

places objects correctly perpendicular to the sound beam

the effects of the sound beam on the body

What instruments measure bioeffects?

Another name for hydrophone

This bioeffects measuring device has a small hypodermic needle with a tiny piece of PZT attached to an oscilloscope with a wire or may contain a very thin membrane of PZT plastic that is placed in the sound beam

What relates to the pressure of the sound beam when using a hydrophone?

What does a hydrophone do?

Hydrophone measurements are displayed on an?

What can a hydrophone determine?

From lowest to highest, what would the ultrasonic output be?

the measurable force on any target caused by a sound beam

radiation force is also referred to as

interaction of sound and light

this demonstrates the shape of the sound beam in a medium

used to measure sound heat, this measures total power through absorption, the beam's total power is calculated by measuring the temperature rise and the time of heating

used to measure sound heat, this tiny electronic thermometer inserted into the sound beam where the temperature is measured. the temperature rise is related to the power at that particular location

used to measure sound heat, this changes color based on the temperature, provided insight into the shape and strength of the sound beam

what is meant by the risk-benefit relationship?

Is there confirmation of harm resulting from the use of ultrasound at standard intensity?

ALARA

what should techs do to maintain alara

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

research performed within the living body

research performed outside the living body in an artificial environment

is it ethical to do all studies in vivo?

searches for a relationship between cause and effect

searches for a relationship between exposure and response

2 mechanisms of bioeffects

bioeffects resulting from tissue temperature elevation

a calculated number useful in predicting max temperature increases under clinically relevant conditions

3 forms of measurement of in vivo tissue temperature changes that are the best

absorption occurs more frequently and at a higher degree in what?

what tissues are less tolerant of tissue heating

how many hours will it take of US exposure to elevate the temperature 2 degrees celcius

Tissue heating is related to what type of intensity

What is worse a focused or unfocused US beam?

interaction of sound waves with microscopic, stabilized gas bubbles in tissues

2 forms of cavitation

this type of cavitation occurs at lower MI levels, gaseous nuclei tend to oscillate (expand and contract) bubble don't burst

this type of cavitation occurs at higher MI levels, bubbles burst, and produces highly localized violent effects such as colossal temperatures and shock waves

what is inertial or normal cavitation

related to the likelihood of harmful bioeffects from cavitation, unitless, related to peak negative pressure and frequency, greater likelihood of cavitation bioeffects with additional negative pressure and lower frequencies

exposure-response population studies ultilizing clinical surveys, many dealing with in utero fetal exposure

3 limitations of epidemiology studies

what make up the best epidemiologic studies?

information is documented as it occurs

creates a control group, takes other risk factors into account

epidemiologic data indicates that ultrasound exposure is not associated with adverse what?

greatest risk in ultrasound is from?

How should electrical hazards be assessed?