9-17

80問 • 1年前

問題一覧

Voltage pulses from the pulser go to the

transducers elements

Gain compensation is necessary due to

attenuation

Which of the following choices is best when the image on your US display reflectors only in a region far from the transducers but no reflectors in a region close to the transducer?

adjust the systems compensation

Which of the following would have the deepest delay on TGC curve

2MHz annular phase

What is a primary advantage of multiple focal zones along each scan line of two dimensional image?

improved lateral resolution

With sector, scanning images with greater detail, spatial resolution are created when the number of acoustic pulses per degree of sector is increased

True

What does the far gain of a depth gain compensation curve represent?

The maximum amplification related to compensation

What is a number of binary digits required to store 29 levels of gray

A sonographer reduces the sector size from 90° to 30° frame rate, however did not change what else happened?

multifocus was turned on

What nonlinear behavior creates tissue harmonics

sound travels faster in compressions and slower in rarefractions

A byte is composed of _____ bits. A word is composed of ____bytes.

8,2

Why is it necessary for the receiver to perform compressions on the electrical signals that is processed?

The dynamic range of the systems electronics is less than the dynamic range of the receive sound reflection

What image is created with a two dimensional array transducer

Three-dimensional real time image

When using an instruments, typical of today’s imaging devices, a higher frequency transducer is likely to mildly improve the systems lateral resolution

True

The dimension perpendicular to the scan plane is called____

Section thickness

Which of the following is defined as changing the time of the shocking of the elements in order to shape and steer the beam

Phasing

The curved pattern of delays in the electrical spikes used in a linear phase. Ray transducer focuses the beams during reception.

False

One way that a sonographer can alter. The actual resolution achieved during an exam is to adjust The maximum imaging depth

false

What frequency transducer will have the best range resolution

10 MHz

When using an instrument, typical of today’s imaging devices, a higher frequency transducer is likely mildly improved the systems lateral resolution

True

With a mechanical transducer, the ultrasound beam is directed in many different directions to create an imaging plane

True

Which of the following studies would typically be performed with a curved sequential array Transducer!

Second trimester obstetric scan

Which receiver function create an image of comparable brightness from top to bottom

Swept gain compensation

Why is it necessary for analog-to-digital conversion to occur prior to the signal reaching the scan converter?

The scan converter can process signals only in binary

Which of the following functions will result in increase in the signal strength of the received beam

Amplification

The output of an ultrasound pulser determines the ___of the acoustic pulse

intensity

A digital representation of a number can achieve only specific values

True

An increase in the amplitude of the transmitted voltage will result in ____?

an increase in the acoustic power

As the sound beam travels, it is attenuation. This explains the needs to have which receiver function.

compensation

Which of the following task is not performed by the receiver of an ultrasound system

degaussing

A sonographer reduces the sector size from 90° to 30° frame rate, however did not change what else happened

Multifocal was turned on

All the following are requirements of contrast agents except

reasonable cost, and or reimbursements

Which of the following is associated with pulse inversion imaging?

Reduce temporal resolution

The transducer has an impedance ____ times that of the tissue

Shortening the pulses in diagnostic ultrasound Bordens the____

bandwidth

How is the piezoelectric property instilled in a man-made crystal material?

The crystal is heated to 328 to 365 Celsius in the presence of magnetic field and then cold

With a 1 D linear array, where is the dimension of the sound beam in the out of plane dimension the narrowest

It is at the point of the mechanical focusing

The ultrasound system in your lab has a transducer with a small footprint. This kind of transducer has the following disadvantages.

resolution is degraded at large distance

You are using a linear array transducer with 4 transmitted focal zones. how many pulses are required on each scan line to create the image?

four

A sonographer adjust an ultrasound scan to double depth of view from 5 cm to 10 cm if the frame rate remains the same, which one of the following also occurs

Narrow sector

A sonographer adjust an ultrasound scan to double the depth of you from 5 cm to rate an imaging depth are inversely 10 cm what happens to the frame rate

It is halved

Which of the following will improve temporal resolution?

increase PRF

A sonographer adjust the sector size from 45° to 90°. If nothing else is changed what happens to the frame rate

It is halved

What is the process of adjusting for path length related attenuation called?

Compensation

Which of the following is associated with highest mechanical index?

Low frequency, extreme peak, rarefactional pressure

Which display is limited to a Single pair of brightness or displayed levels

Binary

Which two factors determine temporal resolution

Speed of sound and depth of view

What happens to an image when the number of bits allocated to each pixel increase?

More shades gray

Which resolution relate more directly to the transducer

Detail

Factors determining axle resolution are the

Number of cycles in the pulse and wavelength

Arrays have additional beams resulting from their multi element structure called

Grating lobes

A technique that averages out the frequencies used to make the image to improve Contrast resolution and reduce speckle is

Frequency compounding

Which of the following actions will improve the signal to Noise ratio

Increase output power

The smallest component of a 3-D image is the

voxel

Which of the following is a standard for data exchange among imaging systems

DICOM

Which of the following is associated with uniform brightness?

Compensation

The ____is where the filtering detection and compression are done

Receiver

Which of the following would have the shallowest delay on the TGC curve?

5 MHz linear phase array transducer

What is the rationale for the ALARA principle

Patient exposure

What is a primary advantage of multiple focal zones along each scan line of two dimensional image

Improve lateral resolution

Under certain conditions and ultrasound system create each image in 0.01 second what is the frame rate?

100 Hz

The length of the pulse does not directly influence the temporal resolution

True

What is the primary advantage of multiple focal zones along each scanline of a two dimensional image?

Improve lateral resolution

What nonlinear behavior creates tissue harmonics

The sound travels faster in compression and slower and refractions

The PCT crystal in the shape of a disk produces a continuous ultrasound wave. The beam is unfocused. The far zone is the only region where the beam dimer exceeds the transducer Diana matter.

True

All the following reduced temporal resolution by increasing the number of pulses per image except

Increasing depth of view

What is the typical voltage of the signal That is the input to the receiver of an ultrasound system

10 mircovolts

What is the shape of the footprint produced by a curved sequential array transducer

smaller convex nearfield, and larger convex Farfield

If the crystal diameter is 4 mm what is the minimum distance perpendicular to the transducer that two objects need to be defined as two separate reflectors on the image?

2mm

What is the main disadvantage of continuous wave (Pedof) transducer?

depth ambiguity

The part of the receiver that reduces low level system noise is the

Rejection

What receiver function converts a negative portion of the signal to positive

Rectification

An advantage of coded excitation is improved

Signal-to-noise ratio

What is the process of adjusting path length related attenuation called?

Compensation

Which of the following functions will result in increase in the signal strength of the receive beAm

Amplification

A sonographer can make an image of uniform brightness by adjusting both alpha power and receiver gain

False

True or false the signal-to-noise ratio remains unchanged when a sonographer adjust receiver game

True

Which of the following task is incorporated in the process of demodulation

Rectification

What is the purpose of the radio frequency shield that is placed around the crystal and backing material of the ultrasound probe

It reduces electromagnetic interfence

Axial resolution is chiefly determined by

pulse duration

ch 6 AP

ユーザ名非公開 · 20問 · 1年前

ch 6 AP