Davies Ultrasound Physics Review
Exam Questions and Answers
1. What action would be most in keeping w the ALARA principle while
performing a diagnostic ultrasound exam? - -Complete the diagnostic scan
in a timely fashion at the lowest output power that achieves a quality image
Advocating use of the ALARA principle (as low as reasonably achievable)
prudently minimizes the risk of bio effects (even tho epidemiological studies
have revealed no known risk associated with the use of diagnostic
ultrasound).
- 2. During performance of an obstetric ultrasound exam, you adjust the
system parameters to improve the image. Which of the following parameters
would increase acoustic exposure? - -Increase transmit power.
The transmit power is the only control listed that will affect the exposure of
the patient to acoustic power. Gain, TGC, and frame averaging (persistence)
do not affect sound transmission and therefore do not affect exposure.
Increasing frequency will not increase exposure.
- 3. To minimize the risk of biologic effects of ultrasound to the fetus, which
imaging mode tradeoff would be most applicable? - -Use M-mode instead of
pulsed-wave Doppler to measure the fetal heart rate.
Pulsed wave Doppler increases the time average intensity compared to M-
mode.
- 4. What potential bioeffect occurs through absorption of sound energy by
tissue? - -Heating
Sound attenuation in tissue is primarily due to absorption (conversion of
ultrasound to heat).
- 5. When practicing universal precautions, you should do all the following
EXCEPT: - -Wash gloves between exams for reuse from one patient to
another. (It is recommended that gloves be worn during every ultrasound
examination. They should be discarded after use).
-wear gloves when there is a potential for contract with patient body fluid
-change gloves when moving from one patient to another
-Wash hands immediately after gloves are removed
- Wear face masks or eye protection whenever there is a possibility of blood
splashing in your face
,- 6. A nosocomial infection is defined as one that: - -Is hospital-acquired
- 7. Thermally induced biologic effects should be preventable by avoiding a
local tissue temperature increase exceeding: - -1°C
- 8. Which intensity descriptor has the lowest numeric value for the
characterization of a pulsed-wave ultrasonic field? - -SATA
SATA, a term that is infrequently used, means spatial average, time average.
Note: I(SPTA) is the spatial peak, time average intensity; I(SPTP) is the spatial
peak, temporal peak.
- 9* Increased tissue heating could occur when you: - -Increase transmit
power
- A study designed to determine if there is an association between an
adverse effect in a population and exposure to a particular agent is an: - -
Epidemiological study
- Which of the following actions is NOT compliant w HIPPA? - -Reviewing
your neighbors medical studies on your hospital PACS system so you can
give her your opinion of her condition
The Health Insurance Portability and Accountability Act (HIPPA) includes rules
to protect the privacy of the individuals health information. This answer
would violate HIPPA
- What does the mechanical index indicate on an ultrasound system? - -The
likelihood of cavitation during an ultrasound exam
Mechanical index is derived from the peak rarefaction pressure and the
ultrasound freq, parameters shown to be associated w onset of cavitation
- In medicine, what do the initials PHI indicate? - -Protected health
information
- 14*What should you limit when the thermal index exceeds 1? - -Exposure
time
- 15*To practice the ALARA principle, which of the following techniques
should you employ? - -Use the lowest transmit power that allows adequate
tissue visualization
Use a high gain and low transmit power
,- The thermal index indicates: - -Estimated temperature increase in tissue
Temperature increase is calculated assuming certain values for the
absorption and thermal properties of tissues and taking into account factors
such as beam geometry, freq and power. Technically, it is the ratio of the
power being produced to the power needed for a 1° C temperature increase
if tissues have the assumed properties
- 17*The operator control most directly adjusts the intensity of the
transmitted pulse? - -Acoustic output (transmit) power
Pulse repetition freq can also affect the intensity, specifically the I(SPTA)
because it affects the duty factor
- Which of the following would show the highest intensity value? - -SPTP
Note that Im is the intensity over the half wave period within the transmit
pulse where it is the greatest! This term is seldom specified
- Which intensity parameter is not applicable for continuous wave
ultrasound? - -SPPA and SAPA refer to pulse average intensities, which do
not apply to continuous wave ultrasound.
- Which of the following would most likely have the highest SPTA value? - -
PW doppler
- Using a hydrophone, you can measure: - -Pressure amplitude and duty
factor
- Which of the following parameters relates to tissue heating? - -Absorption
- 23* Which of the following occurs when you use the maximum system
gain?
Increased tissue heating
Increased risk of cavitation
Fluid particle streaming
Increased sound absorption
None of the above - -None of the above
- You are performing a sonographic examined notice that the thermal index
(TI) is > 1. Any increase in temperature would be greatest in: - -Bone
- The motion of particles in a fluid is sometimes observed in an intense
ultrasound beam. This is termed: - -Acoustic streaming
, Acoustic streaming is defined as an acoustically generated transport of fluid
within the body of the insinuated fluid or tissue (AIUM nomenclature, 09).
This is a mechanical instruction of tissue and sound, where the beam literally
pushes the media. If the medium is a fluid and fluid is free to move or it
particles in the medium are free, they can move in directions determined by
the beam and any obstacles that are present, such as interfaces
- You are performing a sonographic exam and notice that the TI reading is 1.
What does this indicate - -The output level is high enough that temperature
could increase as much as 1° C if the txd were held stationary
- What sonographic application has the lowest FDA approved SPTA values? -
-Ophthalmic
- The following advantage is associated w use of the MI and TI indices: - -
Information is available on the screen to help the sonographer implement
the ALARA principles
- When scanning w pulsed wave doppler, you would affect the acoustic
exposure by changing which of the following? - -Pulse repetition freq
The pulse repetition freq is the number of pulses per second transmitted by
the transducer, which varies w the velocity setting on the spectral display.
Increasing pulse repetition freq has the potential to increase the acoustic
exposure
- What should you do to avoid nosocomial and cross infection w sonographic
probes? - --Probe cleaning should aways proceed high level disinfection
-Disinfection using a germicide compatible w the txd is indicated when the
probe is in contact w mucous membranes
Alone, covering the prove w a condom is insufficient. Proper cleaning of the
probe both before and after the procedure is required. Alcohol wipes are not
recommended by manufacturers as they will degrade the txd surface over
time
- The following illustration depicts acoustic pressure v distance in a medium
in which a sound wave is present What wound parameter is measured by the
length of the bar labeled A in the following illustration? - -Wavelength
- The mass you are imaging has a diameter of 35 mm. This value can also
be expressed as: - -3.5 cm
- Relative measurement of intensity based on a logarithmic scale is
expressed in: - -Decibels
Exam Questions and Answers
1. What action would be most in keeping w the ALARA principle while
performing a diagnostic ultrasound exam? - -Complete the diagnostic scan
in a timely fashion at the lowest output power that achieves a quality image
Advocating use of the ALARA principle (as low as reasonably achievable)
prudently minimizes the risk of bio effects (even tho epidemiological studies
have revealed no known risk associated with the use of diagnostic
ultrasound).
- 2. During performance of an obstetric ultrasound exam, you adjust the
system parameters to improve the image. Which of the following parameters
would increase acoustic exposure? - -Increase transmit power.
The transmit power is the only control listed that will affect the exposure of
the patient to acoustic power. Gain, TGC, and frame averaging (persistence)
do not affect sound transmission and therefore do not affect exposure.
Increasing frequency will not increase exposure.
- 3. To minimize the risk of biologic effects of ultrasound to the fetus, which
imaging mode tradeoff would be most applicable? - -Use M-mode instead of
pulsed-wave Doppler to measure the fetal heart rate.
Pulsed wave Doppler increases the time average intensity compared to M-
mode.
- 4. What potential bioeffect occurs through absorption of sound energy by
tissue? - -Heating
Sound attenuation in tissue is primarily due to absorption (conversion of
ultrasound to heat).
- 5. When practicing universal precautions, you should do all the following
EXCEPT: - -Wash gloves between exams for reuse from one patient to
another. (It is recommended that gloves be worn during every ultrasound
examination. They should be discarded after use).
-wear gloves when there is a potential for contract with patient body fluid
-change gloves when moving from one patient to another
-Wash hands immediately after gloves are removed
- Wear face masks or eye protection whenever there is a possibility of blood
splashing in your face
,- 6. A nosocomial infection is defined as one that: - -Is hospital-acquired
- 7. Thermally induced biologic effects should be preventable by avoiding a
local tissue temperature increase exceeding: - -1°C
- 8. Which intensity descriptor has the lowest numeric value for the
characterization of a pulsed-wave ultrasonic field? - -SATA
SATA, a term that is infrequently used, means spatial average, time average.
Note: I(SPTA) is the spatial peak, time average intensity; I(SPTP) is the spatial
peak, temporal peak.
- 9* Increased tissue heating could occur when you: - -Increase transmit
power
- A study designed to determine if there is an association between an
adverse effect in a population and exposure to a particular agent is an: - -
Epidemiological study
- Which of the following actions is NOT compliant w HIPPA? - -Reviewing
your neighbors medical studies on your hospital PACS system so you can
give her your opinion of her condition
The Health Insurance Portability and Accountability Act (HIPPA) includes rules
to protect the privacy of the individuals health information. This answer
would violate HIPPA
- What does the mechanical index indicate on an ultrasound system? - -The
likelihood of cavitation during an ultrasound exam
Mechanical index is derived from the peak rarefaction pressure and the
ultrasound freq, parameters shown to be associated w onset of cavitation
- In medicine, what do the initials PHI indicate? - -Protected health
information
- 14*What should you limit when the thermal index exceeds 1? - -Exposure
time
- 15*To practice the ALARA principle, which of the following techniques
should you employ? - -Use the lowest transmit power that allows adequate
tissue visualization
Use a high gain and low transmit power
,- The thermal index indicates: - -Estimated temperature increase in tissue
Temperature increase is calculated assuming certain values for the
absorption and thermal properties of tissues and taking into account factors
such as beam geometry, freq and power. Technically, it is the ratio of the
power being produced to the power needed for a 1° C temperature increase
if tissues have the assumed properties
- 17*The operator control most directly adjusts the intensity of the
transmitted pulse? - -Acoustic output (transmit) power
Pulse repetition freq can also affect the intensity, specifically the I(SPTA)
because it affects the duty factor
- Which of the following would show the highest intensity value? - -SPTP
Note that Im is the intensity over the half wave period within the transmit
pulse where it is the greatest! This term is seldom specified
- Which intensity parameter is not applicable for continuous wave
ultrasound? - -SPPA and SAPA refer to pulse average intensities, which do
not apply to continuous wave ultrasound.
- Which of the following would most likely have the highest SPTA value? - -
PW doppler
- Using a hydrophone, you can measure: - -Pressure amplitude and duty
factor
- Which of the following parameters relates to tissue heating? - -Absorption
- 23* Which of the following occurs when you use the maximum system
gain?
Increased tissue heating
Increased risk of cavitation
Fluid particle streaming
Increased sound absorption
None of the above - -None of the above
- You are performing a sonographic examined notice that the thermal index
(TI) is > 1. Any increase in temperature would be greatest in: - -Bone
- The motion of particles in a fluid is sometimes observed in an intense
ultrasound beam. This is termed: - -Acoustic streaming
, Acoustic streaming is defined as an acoustically generated transport of fluid
within the body of the insinuated fluid or tissue (AIUM nomenclature, 09).
This is a mechanical instruction of tissue and sound, where the beam literally
pushes the media. If the medium is a fluid and fluid is free to move or it
particles in the medium are free, they can move in directions determined by
the beam and any obstacles that are present, such as interfaces
- You are performing a sonographic exam and notice that the TI reading is 1.
What does this indicate - -The output level is high enough that temperature
could increase as much as 1° C if the txd were held stationary
- What sonographic application has the lowest FDA approved SPTA values? -
-Ophthalmic
- The following advantage is associated w use of the MI and TI indices: - -
Information is available on the screen to help the sonographer implement
the ALARA principles
- When scanning w pulsed wave doppler, you would affect the acoustic
exposure by changing which of the following? - -Pulse repetition freq
The pulse repetition freq is the number of pulses per second transmitted by
the transducer, which varies w the velocity setting on the spectral display.
Increasing pulse repetition freq has the potential to increase the acoustic
exposure
- What should you do to avoid nosocomial and cross infection w sonographic
probes? - --Probe cleaning should aways proceed high level disinfection
-Disinfection using a germicide compatible w the txd is indicated when the
probe is in contact w mucous membranes
Alone, covering the prove w a condom is insufficient. Proper cleaning of the
probe both before and after the procedure is required. Alcohol wipes are not
recommended by manufacturers as they will degrade the txd surface over
time
- The following illustration depicts acoustic pressure v distance in a medium
in which a sound wave is present What wound parameter is measured by the
length of the bar labeled A in the following illustration? - -Wavelength
- The mass you are imaging has a diameter of 35 mm. This value can also
be expressed as: - -3.5 cm
- Relative measurement of intensity based on a logarithmic scale is
expressed in: - -Decibels
