Test objects and Phantoms

What is the requirements for quality assurance?

multiple evaluations of system's components

repairs

preventative maintenance

record keeping

What is the goals for quality assurance?

proper equipment operation

detect gradual changes

minimize downtime

reduce number of repeat scans

What are the quality assurance methods?

test under known, defined conditions

constant instrument settings

use phantom with measurable characteristics

image in identical environment

A phantom is an ____ standard

objective (factual, real)

What are the test objects and phantoms divided into?

those that measure the acoustic output of the instrument and those that test the operation of the instrument

What does tissue equivalent phantoms assess?

detail resolution (lateral and axial)

contrast resolution (gray scale)

penetration (depth) and dynamic range

time gain compensation

accuracy of depth and distance measurement

Tissue equivalent phantoms has ____ of the material similar to that of soft tissue

attenuation

What are tissue equivalent phantoms made of?

graphite-filled aqueous or urethane rubber

What are the echo producers in tissue equivalent phantoms?

graphite particles

What measures detail resolution and distance accuracy in tissue equivalent phantoms?

thin nylon lines

What do some tissue equivalent phantoms contain for various scattering strengths?

cones or cylinders

What do test objects contain?

nylon lines and scattering layers

What do test objects evaluate?

detail resolution and beam profiles

Do test objects stimulate tissue characteristics?What do they provide?

no; instrument performance

What do the beam-profile slice thickness test objects contain?

thin, scattering layer in an echo-free material

What do the beam-profile slice thickness test objects used to show?

beam width in scan plane or perpendicular to it

3rd dimension

What does multi-purpose tissue-cyst phantom test?

dead zone, detail resolution (lateral and axial), depth accuracy, measurement accuracy, contrast resolution, penetration

What is the AIUM 100mm test object made of?

water-filled with pins

Are IUM 100mm test objects used still?

no

What is an ATS multipurpose phantom used for?

dead zone, vertical and horizontal measurement accuracy, sensitivity/penetration, focal zone, axial and lateral resolution, image uniformity, gray scale and displayed dynamic range

What is the CIRS model 040 phantom used for?

image uniformity, axial and lateral resolution, depth calibration, dead zone

What is the CIRS model 040 phantom most importantly used for?

registration within two different backgrounds of attenuation coefficients (attenuation per cm of wave travel) 0.5 and 0.7 dB/cm/MHz

What is the needle biopsy breast phantom used for?

practice aspirating and biopsying (multiple times)

What is CIRS fetal phantom used for?

assessment of composite measurement techniques and biometric analysis programs

3D reconstructions and surface renderings

What is the CIRS fetal phantom anatomy based on?

published biometric data at normal fetal growth rates of 21 weeks

What is the multipurpose ultrasound phantom Kyoto Kagaku N-365 designed for?

assessment and calibration

What is the multipurpose ultrasound phantom Kyoto Kagaku N-365 made of?

urethane elastomer, acrylic, nylon

What is the speed of sound in a multipurpose ultrasound phantom Kyoto Kagaku N-365?

1440 m/s (25 degrees C)

What is the attenuation rate in a multipurpose ultrasound phantom Kyoto Kagaku N-365?

0.57 dB/cm/MHz

What is a hydrophone?

device used to measure the acoustic output of ultrasound instruments

What is another name for a hydrophone?

microprobe

Who is a hydrophone used by?

engineers and physicists

What is the first form of a hydrophone?

small transducer mounted on the end of a hollow needle (1mm or less)

What is the second form of a hydrophone?

large piezoelectric membrane with small metallic electrodes centered on both sides

What is the membrane of a hydrophone made out of and why?

PVDF (polyvilnylidene fluoride) because of its wide bandwidth

hydrophone

membrane hydrophone

Hydrophones receive sound reasonably well from:

all directions without altering the sound by their presence

A hydrophone measures what?

the pressure in a sound beam

What does a hydrophone produce?

a voltage that can be displayed on an oscilloscope and produces a picture

What can be calculated from the oscilloscope picture?

period, PRP, pulse duration and several other acoustic pulse parameters

Acoustic-optics deal with interaction between:

light and sound waves

Who is acoustic-optics used by?

physicists

What do acoustic-optics study?

characteristics and shape of sound beam

What does acoustic-optics contain?

shadowing system called Schlieren

What does acoustic-optics produce?

2D cross section of beam produced

Are acoustic-optics commercially available?

no, difficult to use

Who is a calorimeter used by?

physicists

What is a calorimeter?

a transducer that turns acoustic energy into heat

What does a calorimeter measure?

temperature increases in absorbing liquid along with time required to obtain the heat (energy to heat)

In a calorimeter, if intensity is known, what can be calculated?

beam area

Is a calorimeter commercially available?

no

calorimeter

What does a thermocouple do?

UIs absorbed, turned into heat

ULS intensity can be measured at specific points

What is a thermocouple?

small device embedded in absorbing material

What does a thermocouple measure?

temperature change

A thermocouple is __ sensitive than a hydrophone.

less

What are crystals?

cholesteric liquid crystals or starch iodine blue

What will crystals do?

turn different colors when hit by different intensities

In crystals what determines the shape and strength of the beam?

shape and color of the crystal

What is the lowest sonographic imaging output?

gray-scale

What is the highest sonographic imaging output?

pulse-spectral doppler

What is the sonographic imaging output in the middle?

M mode and color doppler