Ch. 22 Physics

Question 1

Routine, periodic evaluation of an ultrasound system to gaurantee optimal image quality

Answer 1

quality assurance

Question 2

Who is responsible for implementing a QA action plan

Answer 2

sonographer

Question 3

What are the 4 requirements for a QA program

Answer 3

assessment of system components, repairs, preventative maintenance, record keeping

Question 4

What are the Goals of a QA program

Answer 4

guarantee proper operation of the system, detect gradual changes, minimize downtime, reduce number of non-diagnostic exams, reduce number of repeat exams

Question 5

What are the QA devices

Answer 5

tissue equivalent phantom, doppler phantom, slice thickness phantom (beam profile)

Question 6

Phantoms are an ______ standard

Answer 6

objective

Question 7

completely unbiased, not affected by individuals preference, factual, repeatable, able to be counted

Answer 7

objective

Question 8

Influenced by someone’s opinion or beliefs, results vary

Answer 8

subjective

Question 9

Have ultrasonic features similar to soft tissue, used to evaluate characteristicsof gray scale, texture, multifocus

Answer 9

tissue equivalent phantom

Question 10

With tissue equivalent phantom, _____ is evaluated with this phantom since it contains small scatters that act like _______

Answer 10

gray scale, soft tissue

Question 11

Evaluating ALL doppler components such as color, cw, pw, power

Answer 11

doppler phantom

Question 12

What are the 3 doppler phantoms

Answer 12

vibrating strings, moving belt, flow phantom

Question 13

Assesses the slice thickness and its effect upon image accuracy

Answer 13

slice thickness phantom

Question 14

Slice thickness determines

Answer 14

elevational resolution

Question 15

Slice thickness is most likely to _____ image quality because the imaging plane is _____ than either the beam width or pulse length

Answer 15

degrade, thicker

Question 16

Slice thickness measures the beam geometry _____ to the imaging plane

Answer 16

perpendicular

Question 17

Thicker slices _____ spatial resolutions and ____ the ability to visualize small, low contrast reflectors

Answer 17

diminish, reduce

Question 18

When beam is too thick, cystic structures

Answer 18

may appear filled in

Question 19

Refers to the ability of a system to display LOW LEVEL ECHOES

Answer 19

sensitivity

Question 20

Sensitivity evaluated in what two forms

Answer 20

normal, maximum

Question 21

Region close to the transducer where images are inaccurate

Answer 21

dead zone

Question 22

Dead zone extends from the transducer to the _______ from which meaningful reflections appear

Answer 22

shallowest depth

Question 23

With dead zones, what can help allow accurate imaging of important superficial structures

Answer 23

acoustic standoff/gel pad

Question 24

Ability of the system to place reflections in proper positions while imaging from different orientations

Answer 24

registration accuracy

Question 25

Another name for Range accuracy

Answer 25

vertical depth

Question 26

Describes the systems accuracy in placing reflectors at correct depths located PARALLEL to the sound beam

Answer 26

calibration

Question 27

Describes the systems ability to place echoes in their correct position when the reflectors are PERPENDICULAR to the sound beam

Answer 27

horizontal calibration

Question 28

Smallest distance at which two SIDE BY SIDE pins are displayed as two distinct images (perpendicular to the sound beam)

Answer 28

lateral resolution

Question 29

Smallest distance at which two pins positioned PARALLEL to the sound beam are displayed as two distant echoes

Answer 29

axial resolution

Question 30

Describes the systems ability to display similar reflectors in the phantom with echoes of equal brightness

Answer 30

uniformity