homework review 3 Flashcards
Working in conjunction with their partners in other agencies, the FDA intends to take action to
1. promote safe use of medical imaging devices.
2. support informed clinical decision.
3. increase patient awareness.
all of the options
Which of the following statements is true?
a. Medical imaging personnel absolutely never receive equivalent doses that are close to the annual occupational effective dose limit.
b. Medical imaging personnel almost always receive equivalent doses that are close to the annual occupational effective dose limit.
c. Medical imaging personnel hardly ever receive equivalent doses that are close to the annual occupational effective dose limit.
d. Medical imaging personnel always receive equivalent doses that are close to the annual occupational effective dose limit.
Medical imaging personnel hardly ever receive equivalent doses that are close to the annual occupational effective dose limit.
A radiation safety officer in a health care facility must have sufficient authority, organizational freedom, and management prerogative to
- identify radiation safety problems.
- initiate, recommend, or provide corrective action.
- stop unsafe operations involving by-product material.
- verify implementation of corrective actions.
all of the options
Determine the cumulative effective dose (CumEfD) limit to the whole body of an occupationally exposed person who is 46 years old.
460 mSv
Effective dose (EfD) limits may be specified for
whole-body exposure
partial-body exposure
exposure of individual organs
all of the options
all of the above
The primary function of the Nuclear Regulatory Commission (NRC) is to
oversee the nuclear energy industry.
Upper boundary safe radiation exposure limits for occupationally exposed persons are associated with risks that are similar to those encountered by employees in other industries that are generally considered to be reasonably safe. These industries include
1. manufacturing.
2. trade.
3. government.
all of the options
the effective dose (EfD) limiting system is
the current method for controlling the risk of biologic damage to radiation workers and the general public from radiation exposure.
The ALARA concept adopts an extremely conservative model concerning the relationship between
ionizing radiation and potential risk
Which of the following are functions and/or responsibilities of the United States Occupational Safety and Health Administration (OSHA)?
1. Functions as a monitoring agency in places of employment, predominantly in industry
2. Regulates occupational exposure to radiation through Part 1910 of Title 29 of the U.S. Code of Federal Regulations (29 CFR 1910)
3. Responsible for regulations concerning an employee’s “right to know” with regard to hazards in the workplace
all of the options
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.
all of the options
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
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.
all of the options
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
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 to 100
Luminance is determined by measuring the concentration of light
over a particular field of view.
The control panel, where technical exposure factors are selected and visually displayed for the equipment operator, must be located
behind a suitable protective barrier that has a radiation-absorbent window that permits observation of the patient during any procedure.
When using digital fluoroscopy systems, making use of the last image hold feature can
be an effective dose reduction technique.
What is the purpose of radiographic beam filtration?
To reduce exposure to the patient’s skin and superficial tissues by absorbing most of the lower-energy photons from the heterogeneous beam
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
According to the American College of Radiology (ACR), abdominal radiologic examinations that have been requested after full consideration of the clinical status of a patient, including the possibility of pregnancy, need
not be postponed or selectively scheduled.
According to the U.S. Public Health Service, the genetically significant dose (GSD) for the population of the United States is approximately
0.20 mSv
Analysis of an imaging department’s repeat rate
1. provides valuable information for process improvement.
2. helps minimize patient exposure.
3. improves overall performance of the department.
all of the options
Essentially all diagnostic medical procedures result in fetal exposures ______________, so that _______________________.
of less than 0.01 Gy; the risk of abnormality is very small
Of the following radiologic procedures, which is (are) considered nonessential?
1. A chest x-ray examination automatically scheduled on admission to the hospital
2. Lumbar spine x-ray examination as part of a pre-employment physical
3. Whole-body computed tomography (CT) screening
all of the options
Which of the following is frequently a problem in diagnostic pediatric radiography?
Patient motion
________________________ are the sensing devices most often used to measure skin dose directly.
Thermoluminescent dosimeters
Which of the following must always be the first step in protection of the reproductive organs?
Adequate and precise collimation of the radiographic beam to include only the anatomy of interest
A miscentering of ________ can produce as much as __________% increase in patient dose.
2 cm; 25
For routine head and body computed tomography examinations, effective doses fall into which of the following effective dose ranges?
1 to 10 mSv
In CT because of higher effective energy of the x-ray beam, both ____________ and _______________ interactions contribute substantially to the image.
photoelectric, Compton
In CT when a series of adjacent slices is obtained, some radiation will also scatter from the slice being made into the adjacent slices. What is this radiation called?
interslice scatter
In the early 2000s various publications calculated individual and population risks of cancer from CT based upon risk estimates from studies of which of the following groups of people?
atomic bomb survivor
The movement or advancement of the patient couch during a CT scan is known as
table increment
To keep the patient’s radiation dose ALARA, for both initial and follow-up examinations, the image acquisition should
always be made in the same cardiac phase.
With higher radiation exposure to the patient during a computed tomography examination, there is
an increased associated cancer risk.
Which of the following is not typically used during a CT scan?
a. Direct patient shielding
b. Filtered back projection
c. All of the options
d. A tightly collimated x-ray beam
direct patient shielding
Tube current modulation in CT scanning can
help to reduce patient dose
the primary function of the NRC is to
oversee the nuclear energy industry
which of the following terms involves a random effect of ionizing radiation?
early tissue reactions
reddening of the skin
change in white blood cell count
stochastic event
stochastic event
Breast positioning for Digital Breast Tomography is ______________ for conventional digital mammography.
the same as is used
what is the regulatory standard for total filtration for fixed x-ray units
2.5mm aluminum equivalent
what is the regulatory standard for total filtration for fixed x-ray units: lead or aluminum?
aluminum
during a screening mammography, __________________ between the breast and the support plate of the mammographic x-ray machine can noticeably reduce the degree of pain experienced by a sensitive patient.
some radiolucent cushioning
Digital mammography units with the ability to enhance contrast with image gray-level manipulation offer
substantial improvement for patients with dense breasts.
For rhodium x-ray tube targets, only _____________ filters are used.
rhodium
Performing a 3D mammogram along with a standard mammogram can result in about _________ more breast cancer found for every ____________ women screened when compared with a standard mammogram alone.
one, 1,000
The age recommendation for screening mammography is controversial because mammography is less accurate in the detection of breast cancer in younger women and is likely to result in _________________ readings, leading to unnecessary biopsies in that population.
many false-positive
Which of the following procedures will lower the percentage of false-positive readings caused by very dense breasts and consequently permit a more effective x-ray screening of younger women?
Digital Tomosynthesis
During mammography, axillary projections should be done only on request of the
radiologist
In mammography maintaining and enhancing subject contrast is
of paramount importance for all patients.
The x-ray spectrum used for tomosynthesis is generally similar to that employed in standard digital mammography, and the selected _____________ depends on the thickness and density of the compressed breast.
peak kVp
a solid encapsulated radioactive source (can be/is never to be) touched directly with the hands
is never to be, instead long tongs which add distance should be used.
Any radioactive material that is attached to or associated with dust particles or in liquid form and is found on various surfaces is referred to as
radioactive contamination
Considering the design of the medical imaging suites listed below, which suite requires shielding for the highest energy photons?
PET-CT imaging suite
During a radiation emergency, the dose limit for individuals engaging in lifesaving activities is
250 mSv per event
Gamma rays differ from x-rays
only in the method of how they are produced
Iodine-125 (125I53) has been used quite extensively since 2000 in the form of titanium-encapsulated cylindrical seeds to give a tumoricidal radiation equivalent dose to
cancers that are confined within the prostate gland
Monoclonal antibodies (MAB) are antibodies that preferentially bind always to a specific
part of an antigen that is recognized by the antibody.
the actual long-term health effects of a “dirty bomb” are likely to be
minimal
While a patient receiving Iodine-131 (131I53) therapy is hospitalized, a large, _________, movable lead shield can be positioned between the patient and any attending personnel for protection.
up to 25-mm or 1-inch-thick
The isotopes used in brachytherapy are characterized by
relatively long half-lives that are measured in terms of multiple days, months, or years and, except for a few of them, by relatively high energy emissions.
A protective curtain, or sliding panel, with a minimum of 0.25-mm lead equivalent, should normally be positioned between the fluoroscopist and the patient to intercept what type of radiation?
scatter radiation above the tabletop
For C-arm devices with similar fields of view, the dose rate to personnel located within a meter of the patient is ____________ the dose rate to personnel from ______________.
comparable to, routine fluoro
For primary radiation, what is the term that represents a portion of beam-on time that the x-ray beam is directed at a primary barrier during the week?
use factor
If the peak energy of the x-ray beam is 100 kVp, a protective lead apron must be the equivalent to at least which of the following measures?
0.25mm thickness of lead
The annual effective dose limit for individual members of the general population not occupationally exposed is ___________ for continuous or frequent exposures from artificial sources other than medical irradiation and natural background and ____________ for infrequent annual exposure.
1 mSv, 5 mSv
The maximum weekly permitted equivalent dose for a controlled area must not exceed
1 mSv
most facilities room doors have attenuation for diagnostic energy x-ray equivalent to that provided by _______ mm of lead.
0.8
While standing behind the control-booth barrier, a radiographer makes a radiographic exposure. The x-rays scattered from the patient’s body should ____________________
scatter a minimum of 2 times before reaching any area behind the control-booth barrier.
Who should determine the exact shielding requirements for a particular imaging facility?
medical physicts
