CORE Flashcards
memorized
which of the following statements are correct regarding the link between radiation dose and genetic effects?
- the link has been demonstrated in human studies
- The link has been demonstrated in animal studies
- increased risk to humans cannot be predicted with respect to an individual
2 and 3 only
The link has been demonstrated in human studies
and
increased risk to humans cannot be predicted with respect to an individual
which of the following changes in kilovoltage (KvP) will result in the greatest reduction of patient dose, when milliampere seconds (mAs) is adjusted to compensate for the change?
Increased kvp by 30%
which radiographic imaging systems uses storage phosphors to temporarily store energy representing the image signal?
Computed radiography
what is the primary purpose of using gonad shields during radiography ?
Reduce the likelihood of genetics effects
which of the following are types of gonad shields?
1. Aperture
2. contact
3. shadow
contact and shadow
when should gonad shielding be used ?
when the gonads are within 5 cm of the radiation field
the greatest cause of unnecessary radiation to patients that can be controlled by the limited operator is
repeat exposures
the limited operator can reduce repeat exposures by
clearly instructing patients
how does x-ray beam restriction minimize patient exposure
it limits the radiation field to the area of interest
what is the device that allows the limited operator to vary the size of the radiation field ?
collimator
how does filtration reduce patient exposure
removes longer-wavelength photons
what is the national council on radiation protection and measurements (NCRP) recommendation for the amount of total filtration?
2.5 MM AI equiv
what are the three principal methods used to protect limited operators from unnecessary radiation exposure?
Time , distance, and shielding
which of the following is not a type of personnel radiation shielding ?
shadow
personnel shielding must be worn on the rare occasion during which the limited operator may need to remain in the radiographic room during an exposure to assist the patient in maintaining the proper position. what is the source of the greatest radiation hazard under this circumstance?
scattered radiation from the patient
what is the term for radiation that escapes from the x-ray tube housing ?
Leakage radiation
why are limited operators prohibited from activities that result in direct exposure to the primary x-ray beam ?
They are considered occupationally exposed individuals
distance as a method used to limit operator exposure means that :
The operator should maximize the distance from the source during an exposure .
Shielding worn for personnel protection is designed to attenuate what source of exposure
scatter radiation
which of the following is an acronym for a common type of personnel dosimeter?
TLD
what is the recommended placement for a personnel dosimeter on the body of the limited operator ?
the badge should be worn in the region of the collar on the anterior surface of the body and outside the lead aprons, if worn.
what is the NCRP recommended annual effective dose limit for occupational exposure ?
5.0 rem (50 mSv)
what is the NCRP recommended monthly effective (or equivalent ) dose limit to the fetus for a pregnant worker?
0.05 rem (0.5 mSv)
radiation monitoring of personnel is required when what percentage of the annual occupational effective dose limit is likely to be received ?
10 percent
what is the SI radiation unit express radiation intensity in air?
colomb / kilogram (c/kg)
the SI unit used to report occupational doses to radiation workers is the
MSV
what is the SI radiation unit of absorbed dose?
GRAY
according to the bergonie - tribondeau law ,which of the following types of cells are most radiosensitive ?
Embryonic tissue cells
which type of x-ray photon interaction with the body is PRIMARLY responsible for the radiation dose absorbed by the patient ?
photoelectric
what is the NCRP (report #102) recommendation for lead equivalency of aprons used for personnel protection
0.5 mm
what is erythema, as it relates to radiation exposure
Redding of the skin caused by a high radiation dose
what is the guiding philosophy of radiation protection?
ALARA - as low as reasonably achievable
which of the following statements reflects current scientific opinion regarding the effects of diagnostic levels of ionizing radiation?
There is an increased risk of cancer,leukemia, birth defects and cataracts.
which of the following changes will decrease patient dose?
- increasing the kvp sing the 15 % rule while decreasing the mAS to compensate.
- decreasing the grid ratio to a 6:1 ratio while decreasing the mAs to compensate .
when radiation exposure occurs during pregnancy the greatest risk of birth defects occurs when exposure
- exceeds 5 rad to the uterus
- occurs within the first trimester of pregnancy.
what is the principal source of scatter radiation in radiography?
The patient
at what kvp levels do Compton interactions occur
they occur throughout the diagnostic radiology kvp range.
the greatest portion of the x-ray beam is made up of : Bremsstrahlung radiation
bremsstrahlung radiation
what are the four essential elements required for x-ray production
A target , a vacuum an electron source and a high potential difference
the penetrating power of the x-ray beam is controlled by varying the
kilovoltage (kvp)
which of the following function involve the autotransformer ?
Kvp selection
what is the IR that is used for computed radiography
photostimulable phosphor (PSP plate)
nearly all new x-ray machines manufactured today use
high frequency generators
what is the standard control limit for the field light to radiation field alignment test?
+-2% of SID
the target of the x-ray tube is made of
tungsten
what is standard control limit for the beam (central ray alignment test?
within 1 degree of perpendicular
how often should lead aprons and gloves be checked for cracks or holes
every 6 months
how can detector fog be prevented when using computed radiography cassettes?
Protect the cassette before and after exposure
which of the following will result increased receptor exposure
- increased mA , 2. increased exposure time 3. increased kvp
if the radiographic image is overexposed (exposure indicator out of range ) which of the following changes in exposure factors should be used to correct the problem?
Decrease the mAs
what are the four primary factors of radiographic quality ?
receptor exposure, contrast, spatial resolution and distortion
The relationship between SID and beam intensity is expressed in the :
inverse square law
CONTRAST is PRIMARILY CONTROLLED by the :
processing algorithm
Scatter radiation fog affects radiographic quality by causing
decreased contrast
A change from the small focal spot to the Large focal spot will result in :
decreased spatial resolution
an increase in object image receptor distance OID will result in ;
increased magnification
Motion of the patient the tube or the IR during the exposure will result in decreased
spatial resolution
what does quantum mottle (noise) look like on a radiographic image ?
finely speckled or grainy areas
quantum mottle with a digital imaging system is caused by
the mAs being set too low
which of the following will increase spatial resolution
- increased in SID 2. Decrease in focal spot size
what is the appearance of high signal to noise ratio (SNR) image ?
High contrast and very grainy
if the radiographic image is underexposed (exhibits quantum mottle ) which of the following changes in exposure factors should be used to correct the problem?
increase the mAs
what is the appearance of a low signal to noise ratio (SNR) image ?
high contrast and very grainy
During digital image processing electronic masking should not be used to replace
proper radiographic collimation
which of the following is not a component of a computed radiography plate reader?
Developing solution
what conditions are most important for optimum viewing of radiographic images ?
low room light level
images on radiograph that are not a part of the intended image (jewelry bra hook) are called
artifacts
if the amount of irradiated tissue increases what happens to scatter radiation fog?
scatter radiation fog increases
The most effective and practical way to reduce scatter radiation fog on a radiograph is to :
use a grid or bucky
As a general rule a grid should be employed when the part thickness is greater than
12 cm
Technique charts are based on patient part measurements obtained using an x-ray caliper and are expressed as :
thickness in centimeters .
which of the following pathologic conditions would require a decrease in exposure?
- multiple myeloma
2.emphysema - osteoporosis
how will the anode heel effect if present be seen on an image?
The image will be lighter on the anode end than on the cathode end.
which radiographic quality factor is most affected by angulation of the central ray part or IR?
Distortion
which of the following is not related to spatial resolution in digital radiographic system
bit depth
which of the following is not related to image signal in digital radiography systems ?
matrix Size
which of the following is NOT related to image signal in digital radiography systems?
sampling frequency
when viewing a digital image on a monitor how do you determine if the proper mAs was selected ?
evaluate the exposure index value
which of the following will result in an image with poor spatial resolution
patient motion
which of the following will result in an image with excessive magnification of image structures ?
IR exposure at an OID greater than recommended for a particular body part
what does the acronym PACS stand for?
Picture archiving and communication system
which of the following is not a type of DR image receptor?
photostimulable phosphor plate
which of the following will result in an image with excessive distortion of anatomic structures?
improper central ray angulation for the selected radiographic projection
which of the following would be a violation of patient confidentiality ?
A limited operator talks to his or her friend during lunch about a patients imaging procedure
which of the following are true regarding informed consent ?
informed consent may be revoked at anytime and the patient must be legally competent to sign.
A limited operator innocently commits an error as a result of the orders of his or her employer,a physician . The employer may be held responsible according to the….
doctrine of respondeat superior
communication has been validated when the speaker has
received a response from the listener that demonstrates comprehension
which of the following is not a form of nonverbal communication
speaking
limited operator does not clean the bucky device after performing an examination on a patient with influenza
indirect contact or fomite transmission
correct statements of proper body mechanics ?
- used a broad stance 2. carry heavy objects close to your body
standard precautions involve the use of barriers when ever contact is anticipated with
blood , body fluids and mocous membranes
the process of reducing the probability that infectious organisms will be transmitted to a susceptible individual is called:
asepsis
A health care workers single best protection against disease is :
frequent hand washing
a limited operator who does not change linens between patients is:
providing an opportunity for fomite transmission
what is the basic life support system used to ventilate the lungs and circulate the blood in the event of cardiac or respiratory arrest
CPR
what is anaphylaxis?
severe allergic reaction
when a patient in cardiac arrest presents with a rapid, weak, and ineffective heartbeat, what device is used to return the heart to a normal rhythm ?
AED
what is the most common site for palpation of a patients pulse?
Radial artery at the wrist
which of the following vital signs can be assessed without touching the patient ?
Respiration
what is the relationship between the kvp and receptor exposure
direct and not proportional
