Exam 2: 3, 5, & 11

Most fluoroscopic examinations employ a range of _____________ kVp for adult patients, depending on the body area being examined.

75 to 110

During a fluoroscopic examination, a resettable cumulative timing device measures the x-ray beam-on time and sounds an audible alarm or in some cases temporarily interrupts the exposure after the fluoroscope has been activated for what length of time?

5 minutes

During interventional procedures, high-level control fluoroscopy is employed, resulting in a _______________________ or entrance dose rate to the patient to allow the examination of smaller and lower-contrast objects that are not ordinarily discerned during standard fluoroscopy.

Higher entrance exposure rate

Computed radiography, because of its higher exposure latitude, makes grid use on the pediatric population _______________.

Less necessary than was previously believed.

What is the purpose of radiographic beam filtration?

To reduce exposure to the patients skin and superficial tissues by absorbing most of the lower-energy photons from the heterogenous beam.

The protective tube housing serves as a shield against _____________________ entering the x-ray tube, thereby preventing electric shock while also facilitating the cooling of the x-ray tube.

The high voltage

In digital radiography the number of different shades of gray that can be stored in memory and displayed on a computer monitor is termed _________.

Grayscale

When an exposed computed radiography imaging plate is ready to be processed, an imaging reading unit is used to scan the photostimulable phosphor imaging plate with ______________.

Helium-neon laser beam

Fluoroscopic devices are capable of subjecting the patient, the equipment operator, and other personnel near the fluoroscopic equipment to substantial doses of ionizing radiation. These devices include:

1. C-arm fluoroscopes.

2. fluoroscopes on stationary equipment with HLC mode used for interventional procedures.

3. biplane interventional fluoroscopic systems.

1, 2, and 3

In standard image intensification fluoroscopy, an x-ray beam half-value-layer (HVL) of 3 to 4.5 mm aluminum is considered acceptable when kVp ranges from ________.

80-100

Digital radiography images can be accessed,

At several workstations at the same time, thus making image viewing very convenient by physicians providing patient care.

When using digital fluoroscopy systems, making use of the last image hold feature can _________________.

Be an effective dose reduction technique.

The control panel, where technical exposure factors are selected and visually displayed for the equipment operator, must be located where?

Behind a suitable protective barrier that has a radiation-absorbent window that permits observation of the patient during any procedure.

When generator settings are changed from one mA and time combination to another, the most that linearity can vary is ______.

10%

Current federal standards limit entrance skin exposure rates of general-purpose intensified fluoroscopic units with maximum technique factors engaged to a maximum of ________________, as measured at the tabletop using an average phantom, with the image intensifier entrance surface at a prescribed 30 cm above the tabletop.

88 mGya/min

Total filtration of _______________________ for fixed x-ray units operating above 70 kVp is the regulatory standard.

2.5 mm aluminum equivalent

All digital imaging devices are subject to certain artifacts such as:

1. aliasing.

2. moirè patterns.

3. contouring.

1, 2, and 3

If the luminance of the collimator light source is sufficient, the localizing light beam will be able to satisfactorily outline the margins of the radiographic beam on the area of clinical interest on ______________.

Patients of all skin pigmentations.

Luminance is determined by measuring the concentration of light ______________.

Over a particular field of view

When performing a mobile radiographic procedure, to reduce the radiation exposure to the patient, the radiographer must use a minimal source-skin distance of at least ______.

30 cm

Which of the following materials is commonly used in the tabletop of a radiographic examination table to make the tabletop as radiolucent as possible so that it will absorb only a minimal amount of radiation, thereby reducing the patient's radiation dose?

Carbon fiber material

When obtaining a dorsoplantar projection of a foot, which of the following types of filters should be used to provide a greater uniform density of the anatomy?

Wedge filter

Of the following procedures, which involve extended fluoroscopic time?

1. Biliary drainage

2. Stent and filter placement

3. Urinary or biliary stone removal

1, 2, and 3

Digital radiography systems offer several advantages over computed radiography. Some of these include:

1. lower dose.

2. ease of use.

3. immediate imaging results.

4. manipulation of the image.

1, 2, 3, and 4

When a fluoroscopic image is electronically amplified by the use of an image intensification system, which of the following benefits results?

1. Increased image brightness

2. Saving of time for the radiologist

3. Patient dose reduction

1, 2, and 3

Three different filters are incorporated into the detector packet of the optically stimulated luminescence dosimeter. Of what are these filters made?

A. Aluminum, tin, and copper

B. Aluminum, tin, and lead

C. Zinc, copper, and barium

D. Zinc, copper, and lead

A. Aluminum, tin, and copper

What is the maximum period of time that a thermoluminescent ring dosimeter (TLD) may be worn as a personnel device?

A. 1 hour

B. 1 week

C. 1 month

D. 3 months

D. 3 months

What do optically stimulated luminescence dosimeters, thermoluminescent ring dosimeters, and personnel direct ion storage dosimeters have in common?

A. These devices are all used for area monitoring.

B. These devices all use the same sensing material to detect ionizing radiation.

C. These devices are all used for personnel monitoring.

D. Each of these devices can only be used for personnel monitoring for a maximum of 6 months.

C. These devices are all used for personnel monitoring.

Which of the following instruments is called a cutie pie?

A. Geiger-Műller survey meter

B. Ionization chamber-type survey meter

C. Optically stimulated luminescence dosimeter

D. Proportional counter

B. Ionization chamber-type survey meter

Which of the following instruments generally has a check source of a weak, long-lived radioisotope located on one side of its external surface to verify its constancy daily?

A. Personnel direct ion storage dosimeter

B. Proportional counter

C. Geiger-Műller survey meter

D. Ionization chamber-type survey meter

C. Geiger-Műller survey meter

Which of the following devices contains an aluminum oxide detector?

A. Personnel direct ion storage dosimeter

B. Optically stimulated luminescence dosimeter

C. Proportional counter

D. Thermoluminescent ring dosimeter

B. Optically stimulated luminescence dosimeter

When the sensing material contained in the thermoluminescent ring dosimeter is irradiated, which of the following occurs?

A. The protons in the crystalline lattice structure of the LiF molecule absorb energy and are excited to a higher energy level or bands.

B. The neutrons in the crystalline lattice structure of the LiF molecule absorb energy and are excited to a higher energy level or bands.

C. Some of the electrons in the crystalline lattice structure of the LiF molecule absorb energy and are excited to higher energy levels or bands.

D. The electrons freed from the LiF molecule are trapped at a lower energy level or bands.

C. Some of the electrons in the crystalline lattice structure of the LiF molecule absorb energy and are excited to higher energy levels or bands.

Because of the OSL dosimeter's sensitivity down to as low as 10 µSv for x-ray and gamma ray photons in the energy range 5 keV to 40 MeV, it is an excellent and practical monitoring device for

A. employees working in high-radiation environments and for non-pregnant workers.

B. employees working in low-radiation environments and for pregnant workers.

C. members of the general public not occupationally employed.

D. pregnant employees working in high-radiation environments.

B. employees working in low-radiation environments and for pregnant workers.

The effective atomic number (Zeff) of lithium fluoride (LiF) is equal to

A. 5.9.

B. 6.4.

C. 7.0.

D. 8.2.

D. 8.2.

Which of the following are advantages of the personnel direct ion storage dosimeter?

1. Instant access to reports

2. No waiting time for mailing dosimeters

3. Lightweight and durable

4. Can be dropped or scratched with little chance of harm to the device

A. 1, 2, and 3 only

B. 1, 2, and 4 only

C. 2, 3, and 4 only

D. All of the options

D. All of the options

How is the readout for a personnel direct ion storage dosimeter obtained?

A. By hand processing in specific chemical solutions

B. By measuring the amount of light emitted from its sensing material

C. Through a physical connecting device such as a universal serial bus (USB) or via wireless connection

D. By heating the sensing material in the device to a specific temperature

C. Through a physical connecting device such as a universal serial bus (USB) or via wireless connection

Which of the following are disadvantages of the TLD ring dosimeter?

A. Thermoluminescence readings will be lost if not carefully recorded.

B. The readout process destroys information stored in the TLD ring dosimeter, thus preventing the "read" from serving as a permanent legal record of exposure.

C. Calibrated dosimeters must be prepared before-hand and read with each group of TLDs as they are processed.

D. All of the options.

D. All of the options.

Which component(s) of the Geiger-Muller survey meter alerts the operator to the presence of ionizing radiation?

A. The shield covering the probe's sensitivity chamber

B. An audio amplifier and speaker

C. The metal that encloses the counter's gas-filled tube

D. The meter scale

B. An audio amplifier and speaker

Which of the following is not a requirement that radiation survey instruments must meet?

A. They must all be equally sensitive in the detection of all types of ionizing radiation.

B. They should be able to detect all common types of ionizing radiation.

C. They should be calibrated annually to ensure accurate operation.

D. They should interact with ionizing radiation similarly to the method human tissue reacts, permitting dose to be determined more accurately.

A. They must all be equally sensitive in the detection of all types of ionizing radiation.

Medical physicists use ionization chambers, connected to electrometers to perform the annual standard measurements required by state, federal, and health care accreditation organizations for radiographic and fluoroscopic devices. These annual measurements include

1. x-ray output in Gy or mGy.

2. fluoroscopic radiation entrance rates in mSv/min or R/min.

3. kVp setting accuracy.

4. exposure time exactness.

5. half-value layers, or beam quality.

A. 1, 2, and 3 only

B. 1, 3, and 4 only

C. 2, 3, and 5 only

D. All of the options

D. All of the options

When changing employment, what must a radiation worker convey to his/her new employer?

A. A list of all fluoroscopic procedures performed daily

B. A list of all radiographic procedures performed daily

C. Data pertinent to accumulated permanent equivalent dose to be placed on file

D. A report of all procedures performed when "on call" after regular hours

C. Data pertinent to accumulated permanent equivalent dose to be placed on file

The personnel direct ion storage dosimeter provides an instant read-out of dose information when connected to a computer via a connector such as a (an)

A. universal serial bus (USB).

B. charge-coupled device.

C. electrometer.

D. ionization chamber.

A. universal serial bus (USB).

The front of the white paper packet of the optically stimulated luminescence (OSL) dosimeter

A. may be color coded to facilitate correct usage and placement of the dosimeter on the body of occupationally exposed personnel.

B. must not have any type of printing on it.

C. must be radiopaque.

D. must never be exposed to ionizing radiation.

A. may be color coded to facilitate correct usage and placement of the dosimeter on the body of occupationally exposed personnel.

Three different filters are incorporated into the detector packet of the optically stimulated luminescence (OSL) dosimeter. These filters are respectively made of

1. aluminum.

2. copper.

3. molybdenum.

4. rhenium tungsten.

5. tin.

A. 1, 2, and 3 only

B. 1, 2, and 4 only

C. 1, 2, and 5 only

D. 2, 4, and 5 only

C. 1, 2, and 5 only

An ionization chamber connected to an electrometer is a device that can measure

A. electromagnetic force.

B. tiny electric currents with high precision and accuracy.

C. potential difference.

D. voltage in an x-ray machine circuit.

B. tiny electric currents with high precision and accuracy.

Which of the following personnel monitoring devices can be used to provide an immediate exposure readout for a radiation worker?

A. Personnel direct ion storage dosimeter

B. Optically stimulated luminescence dosimeter without an in-house reader

C. Thermoluminescent ring dosimeter

D. All of the options

A. Personnel direct ion storage dosimeter

Which of the following is a disadvantage of the optically stimulated luminescence dosimeter?

A. Exposure not determinable on the day of occurrence without an in-house reader

B. Mechanical shock can cause false high reading

C. No permanent, legal record of exposure

D. Not cost-effective for large numbers of personnel

A. Exposure not determinable on the day of occurrence without an in-house reader

Whenever the letter "M" appears under the current monitoring period or in the cumulative columns of a personnel monitoring report, it signifies that a (an)

A. mistake has been made in recording the equivalent dose.

B. equivalent dose higher than the minimum measurable radiation quantity was recorded during that time.

C. equivalent dose below the minimum measurable radiation quantity was recorded during that time.

D. maximal equivalent dose has been exceeded during that time.

C. equivalent dose below the minimum measurable radiation quantity was recorded during that time.

The optically stimulated luminescence (OSL) dosimeter is "read out" by using a (an)

A. densitometer.

B. ionization chamber.

C. thermoluminescent analyzer.

D. laser light at selected frequencies.

D. laser light at selected frequencies.

Some of the advantages of the optically stimulated luminescence (OSL) dosimeter are

1. can be used for up to 1 year.

2. lightweight, durable, and easy to carry.

3. integrated, self-contained, preloaded packet.

A. 1, and 2 only

B. 1, and 3 only

C. 2, and 3 only

D. All of the options

D. All of the options

Particles associated with electromagnetic radiation that have neither mass nor electric charge are

a. ions.

b. negatrons.

c. positrons.

d. x-ray photons.

d. x-ray photons.

Although coherent scattering is most likely to occur ____________, some of this unmodified scattering occurs throughout the diagnostic range and may result in small amounts of radiographic fog.

a. at less than 10 keV

b. between 30 keV and 60 keV

c. between 60 keV and 90 keV

d. above 100 keV

a. at less than 10 keV

Which of the following is not a type of interaction between x-radiation and biologic matter?

a. Compton scattering

b. Bremsstrahlung

c. Pair production

d. Photoelectric absorption

b. Bremsstrahlung

The symbol Z indicates

a. atomic number of an atom.

b. atomic weight of an atom.

c. fluorescent yield.

d. the number of vacancies in an atomic shell.

a. atomic number of an atom.

In photoelectric absorption to dislodge an inner-shell electron from its atomic orbit, the incoming x-ray photon must be able to transfer a quantity of energy

a. less than the energy that holds the atom together.

b. 10 times as great as the energy that holds the atom together.

c. as large as or larger than the amount of energy that holds the electron in its orbit.

d. equal to or greater than 1.022 MeV, regardless of the energy that holds the electron in its orbit.

c. as large as or larger than the amount of energy that holds the electron in its orbit.

Which of the following interactions between x-ray photons with matter involve a matter-antimatter annihilation reaction?

a. Compton scattering

c. Pair production

b. Coherent scattering

d. Photoelectric absorption

c. Pair production

The probability of occurrence of photoelectric absorption _________ as the energy of the incident photon decreases and the atomic number of the irradiated atoms _________.

a. increases markedly; decreases

b. decreases markedly; increases

c. increases markedly; increases

d. stays the same; increases

c. increases markedly; increases

Which of the following terms refers to the radiation that occurs when an electron spontaneously drops down from an outer shell of an ionized atom to fill a vacancy in an inner shell of that atom?

a. Characteristic photon, or characteristic x-ray

b. Bremsstrahlung

c. Photoelectric radiation

d. Primary radiation

a. Characteristic photon, or characteristic x-ray

Fluorescent radiation is also known as

a. characteristic radiation.

b. coherent scattering.

c. Compton scattering.

d. unmodified scattering.

a. characteristic radiation.

What is the effective atomic number of compact bone?

a. 5.9

b. 7.4

c. 7.6

d. 13.8

d. 13.8

Which of the following is not another term for coherent scattering?

a. Characteristic

b. Classical

c. Elastic

d. Unmodified

a. Characteristic

Which of the following are by-products of photoelectric absorption?

a. Photoelectron and Compton-scattered electron

b. Low-energy scattered x-ray photon and characteristic photon

c. Low-energy scattered x-ray photon and Compton-scattered electron

d. Photoelectron and characteristic photon

d. Photoelectron and characteristic photon

Which two interactions between x-radiation and matter may result in the production of small-angle scatter?

a. Photoelectric absorption and Compton scattering

b. Coherent scattering and Compton scattering

c. Photoelectric absorption and pair production

d. Coherent scattering and pair production

b. Coherent scattering and Compton scattering

Which of the following particles is considered to be a form of antimatter?

a. Electron

b. Positron

c. X-ray photon

d. Scattered x-ray photon

b. Positron

Which of the following interactions results in the conversion of matter into energy?

a. Classical scattering

b. Photoelectric absorption

c. Modified scattering

d. Annihilation reaction

d. Annihilation reaction

Compton scattering is synonymous with

a. coherent scattering.

b. incoherent scattering.

c. photoelectric absorption.

d. photodisintegration.

b. incoherent scattering

Compton scattering is also known by the following terms:

• Incoherent scattering

• Inelastic scattering

• Modified scattering

It is responsible for most of the scattered radiation produced during radiologic procedures. This scatter may be directed forward as small-angle scatter, to the rear as backscatter, and laterally as side scatter.

During the process of coherent scattering, an incident low-energy x-ray photon interacts with

a. a single inner-shell electron, ejecting it from its orbit.

b. a single outer-shell electron, ejecting it from its orbit.

c. an atom and may transfer its energy by causing some or all of the electrons of the atom to momentarily vibrate and radiate energy in the form of electromagnetic waves.

d. a scattered photon of lesser energy, annihilating it.

c. an atom and may transfer its energy by causing some or all of the electrons of the atom to momentarily vibrate and radiate energy in the form of electromagnetic waves.

What is the term for the number of x-rays emitted per inner-shell vacancy during the process of photoelectric absorption?

a. Characteristic absorption

b. Classical gain

c. Fluorescent yield

d. Modified pair production

c. Fluorescent yield

The term fluorescent yield refers to the number of x-rays emitted per inner-shell vacancy. Because the Auger effect is more prevalent in materials with higher atomic number atoms, the fluorescent yield per photoelectron is generally lower in such materials than for substances with low atomic numbers

Which of the following results in all-directional scatter?

a. Classical interaction

b. Coherent interaction

c. Photoelectric interaction

d. Compton interaction

d. Compton interaction

Annihilation radiation is used in which of the following modalities?

a. Computed tomography

b. Digital mammography

c. Positron emission tomography

d. Computed radiography

c. Positron emission tomography

The x-ray photon energy required to initiate pair production is

a. 0.511 keV.

b. 1.022 keV.

c. 0.511 MeV.

d. 1.022 MeV.

d. 1.022 MeV.

If two anatomic structures have the same density and atomic number but one is twice as thick as the other, the thicker structure will absorb

a. the same number of x-ray photons.

b. twice as many x-ray photons.

c. four times the number of x-ray photons.

d. eight times the number of x-ray photons.

b. twice as many x-ray photons.

Since the density of air is approximately _________________ than that of soft tissue, a given volume of air will interact with far fewer x-ray photons than adjacent regions of soft tissue, thereby permitting more radiation to reach the image receptor.

a. 1000 times smaller

b. 1000 times larger

c. 100 times smaller

d. 100 times lager

a. 1000 times smaller

When an inner electron is removed from an atom in a photoelectric interaction, thus causing an inner-shell vacancy, the energy liberated when this vacancy is filled can be transferred to another electron of the atom, thereby ejecting that electron, instead of emerging from the atom as characteristic radiation. What is this electron called?

a. Auger electron

b. Compton electron

c. Edison electron

d. Sievert electron

a. Auger electron

X-rays are carriers of

a. disease.

b. electrons.

c. fluorescent properties that make them visible.

d. manmade electromagnetic energy.

d. manmade electromagnetic energy.