chapter 4-6 assignment

_____ Is a decrease of intensity, power, or amplitude of a sound wave as it travels or propagates.

Attenuation

Match each definition to the correct term.

A. The propagation of time during which a system is operated

B. The length or distance that an entire pulse occupies in space

C. The number of pulses of a repeating signal in a specified unit of time

D. The pulse of ultrasound signal and the pause time

E. The time interval between a reference point on the leading edge of a pulse wave form and a reference point on the trailing edge of the same waveform

A. Duty factor

B. Spatial pulse length

C. Pulse repetition frequency

D. Pulse repetition period

E. Pulse Duration

Increasing the frequency on a multi frequency transducer from 3.5 MHz to 5.0 MHz will:

A. Decrease the pulse repetition frequency

B. Decrease the wavelength

C. Increase the sound propagation speed

D. Increase the pulse length

E. Increase penetration

B. Decrease the wavelength

Which of the following is true regarding the half value layer (HVL) Thickness for a 10 MHz transducer in soft tissue:

A. Two answer choices are correct

B. It represents the point of which the beam intensity is reduced by ½

C. It occurs at a shallow word depth than the HVL for a 5 MHz transducer

D. It represents a 3 dB decrease in signal intensity

E. Three answer choices are correct

E. Three answer choices are correct

Pulse reputation period is unrelated to period. True or false

True

The term duty factor describes:

A. The fraction of time between the transmitted sound pulses

B. The fraction of time the transducer is actively transmitting sound

C. The fraction of time required for round-trip travel of a sound pulse to 1 cm in tissue

D. The fraction of time between the transmitted and received sound pulse

E. The fraction of time the transducer is actively receiving sound

B. The fraction of time the transducer is actively transmitting sound

Referring to the image, which of the following statements are true?

A. Wave A is imaging shallower

B. Wave B is imaging deeper

C. Wave A is imaging deeper

D. Wave A and B are imaging at the same depth

C. Wave A Is imaging deeper

How is PRF related to depth of view?

A. PRF and depth are unrelated

B. Proportionally

C. Inversely

D. If PRF increases, then so will the depth of view

C. Inversely

If the number of cycles in a pulse is increased, but the wavelength remains the same, which of the following is true?

A. The pulse duration is increased

B. The propagation speed is increased

C. The bulk modulus is decreased

D. The period is decreased

E. The frequency is decreased

A. The pulse duration is increased

Match the definition to the correct intensity related term

A. Refers to distance or space

B. The calculated central value of a set of numbers

C. The highest value

D. Refers to a time with regard to transmit and receive

E. Refers to time with regard to transmit only

A. Spatial

B. Average

C. Peak

D. Temporal

E. Pulsed

Refraction can occur with normal incidents. True or false?

False

Your imaging the interface between two abdominal structures at normal incidents. They have the same acoustic impedance. What will occur at the boundary of the two structures?

A. Some of the sound will be refracted

B. Most of the sound will be absorbed by the media boundary

C. All of the sound will be transmitted

D. All of the sound will be reflected

E. Some of the sound will be reflected on some of the sound will be transmitted

C. All of the sound will be transmitted

Which of the following statements is true regarding the effect of frequency on Rayleigh scattering?

A. Scattering intensity is proportional to frequency raised to the fourth power

B. Doubling the frequency results in quartering the scattering intensity

C. Doubling the frequency results in halving the scattering intensity

D. The amount of scattering is not affected by frequency

E. Scattering intensity doubles if frequency is doubled

A. Scattering intensity is proportional to the frequency raised to the fourth power

The arrow indicates _____ _____ If it is in reference to time or _____ _____ _____ If it is in reference to distance.

Pulse duration; Spatial pulse length

Which of the following intensities is related to bio effects?

A. SPTA

B. SATA

C. SPTP

D. SAPA

A. SPTA

How is absorption affected when frequency is increased?

A. Decrease

B. Remains the same

C. Increases

C. Increases

According to snell’s law, The angle of transmission is related to the incident beam angle and

A. ½ the angle of incidence

B. The relative velocities of sound in the two media

C. The amount of acoustic impedance mismatch that occurs at an interference

D. The percentage of defraction, distant to the interface

B. The relative velocities of sound in the two media

Intensity equals the concentration of energy. True or false.

True

How many cycles are in the pulse indicated by the arrow?

2

A pulse ultrasound beam has different intensities at different times. True or false?

True

If you increase the number of cycles in a pulse, both pulse duration and spatial pulse length will increase.

True or false

True

The units associated with the attenuation coefficient is decibels per centimeter. true or false?

True

By increasing imaging depth, the PRF will _____ ; the PRP will _____.

A. Increase, decrease

B. Increase, increase

C. Decrease, increase

D. Decrease, decrease

C. Decrease, decrease

How is PRF related to the operating frequency?

A. Proportionally

B. If PRF increases, so will the operating frequency

C. PRF and operating frequency are unrelated

D. Inversely

C. PRF and operating frequency are unrelated

PRF is adjustable by the sonographer. True or false

True

In order for refractions to occur, there must be a change in propagation speed, and there must be an oblique angle. True or false

True

Order the intensities from smallest to largest

SATA

SPTA

SPPA

IMAX

SPTP

During an ultrasound, you image the following structures. Which is the most attenuating?

A. Gallstones

B. Spleen

C. Blood

D. Bile

Gallstones

Which of the following increases as frequency increases?

A. Scattering

B. Attenuation

C. Absorption and attenuation

D. Absorption

E. All the answer choices are correct

All the answer choices are correct

Referring to the image, this arrow can be adjusted or altered by the sonographer. True or false

False

A waves intensity is 3mW/cm2. There is an increasing change of 9 dB. What is the final intensity?

24 mW/cm2

A relative measurement of intensity based on a logarithmic scale is expressed in

A. Watts per centimeters squared

B. Nepers

C. Newtons per centimeter squared

D. Decibels

E. Pascals

D. Decibels

Order the mediums from highest attenuation to lowest attenuation.

Air

Lung

Muscle

Soft tissue

Fat

Blood

Water

Scattering is the most dominant factor that causes attenuation. True or false.

False

A long pulse duration is preferred for imaging in order to create the most accurate image. True or false?

False

In order for reflections to occur, there must be a change in density and/ or propagation speed. True or false

True

Only three things change when the depth is altered. Those three things are:

A. PRP, PRF, DF

B. PRP, SPL, PRF

C. PD, SPL, DF

D. PRP, PRF, PD

A. PRP, PRF, DF

Which of the following is the highest intensity?

SPTP

SPTA

SATA

SAPA

SPTP

The sonographer is having difficulty penetrating the liver and decreases the frequency for better visualization. Categories each term as to whether it increases, decreases or remains the same.

• Duty factor

• Wavelength

• Pulse repetition frequency

• Frequency

• Period

• acoustic velocity

Increases:

• Wavelength

• Period

Decreases:

• Frequency

Remains The Same:

• Duty factor

• Pulse repetition frequency

• Acoustic velocity

What must be present for sound reflection to occur at the interface of two structures?

• Different attenuation coefficients

• Oblique incidence at the interface boundary

• Different media diameters

• A difference in the acoustic impedance of the media

• Temperature differences between the two media

A difference in the acoustic impedance of the media

How many cycles in a pulse are typical for clinical imaging?

2-4

The attenuation coefficient for soft tissue is roughly 5.0 dB/cm/MHz. True or false?

False

Categories the following terms as to whether they can be adjusted by the sonographer

• Pulse repetition period

• Period

• Spatial pulse length

• Acoustic velocity

• Power

• PRF

• Frequency

• Amplitude

• Duty factor

• Pulse duration

• Intensity

• Wavelength

Adjustable:

• Pulse repetition period

• Power

• PRF

• Amplitude

• Duty factor

• Intensity

Not adjustable

• Spatial pulse length

• Acoustic velocity

• Period

• Frequency

• Pulse duration

• Wavelength

Which of the following adjustments will increase the duty factor?

• increasing time gain compensation

• Increasing scanning time

• Increasing pulse repetition frequency

• Increasing receiver gain

• Increasing output power

Increasing pulse repetition frequency

You have increased the output power by 10 dB. How much have you increased the signal intensity?

• Intensity increased by a factor of 10

• Intensity tripled

• Intensity doubled

• Intensity increased by a factor of 100

• Intensity quadrupled

Intensity increased by a factor of 10

Correctly categorize the terms By more attenuation or less attenuation.

• Lower Frequency

• Higher frequency

• Longer distances

• Shorter path lengths

More attenuation:

• Higher frequencies

• Longer distances

Less attenuation:

• Lower frequency

• Shorter path lengths

An ultrasound beam has the exact same intensity at all locations. True or false

False

If the light of a flashlight is used to illuminate a small area, and then it changed to a large area, what happens to the intensity?

• Decrease

• Remains the same

• Increases

Decreases

The beam is always “ On” For continuous wave, ultrasound, therefore the pulse average intensity and temporal average intensity are the same. True or false?

True

The attenuation coefficient is the number of decibels of attenuation that occurs when sound travels

• 13cm

• 13mm

• 1mm

• 1cm

1cm

Pulse repetition period is described by an “on” And “off” Time is also described as “talk” and “ Transmit” time. True or false?

False

Referring to the image, pulsed wave A Has a higher pulse repetition frequency? True or false

False

Categorize the terms where they best fit: thin half boundary layer, Thick boundary layer

• Media with high attenuation rate

• Media with low attenuation rate

• Bone

• Urine or other biological fluid

• High frequency sound

• Low frequency sound

Thin half boundary layer :

• Bone

• Media with a high attenuation rate

• High frequency sound

Thick half boundary layer:

• Low frequency sound

• Media with low attenuation rate

• Urine or other biological fluid

If you are looking directly into a flashlight and replace the bulb with a brighter bulb, what happens to the intensity?

• Increases

• Remains the same

• Decreases

Increases

Referring to the image above, what is indicated by the arrow?

• Spatial pulse length

• Pulse repetition frequency

• Wavelength

• Pulse repetition period

Pulse repetition period

During an ultrasound examination with a multi frequency, transducer, which frequency should you choose if you wish to effectively reduce attenuation as much as possible?

• 3.5 MHz

• 5 MHz

• 3.0 MHz

• 4.0 MHz

3.0 MHz

The intensity transmission coefficient at the interface between two structures Equals 1%. What is the intensity reflection coefficient?

• 1%

• 100%

• 99%

• 0%

99%

Which of the following does not affect impedance?

• Stiffness

• Frequency

• Propagation speed

• Density

• Answer choices affect impedance

Frequency

The incident intensity always equals

• Reflected intensity plus transmitted intensity

• Reflected intensity, minus transmitted intensity

• Reflected intensity minus transmitted frequency

• Reflected intensity plus transmitted frequency

Reflected intensity plus transmitted intensity

Referring to the image above, if you increase what is indicated by the anrrow above, what else will change?

• Off time

• More than one answer choice is correct

• On time

• Pulse duration

More than one answer choice is correct

While performing an ultrasound of the thyroid gland, you adjust the acoustic power by -3 dB. Which of the following most accurately describes the adjustment?

• The intensity has been quadrupled

• The intensity has been doubled

• The intensity has been quartered

• The intensity has been halved

• The intensity has been increased 10 times

The intensity has been halved