Principles 8 9 10 11 exam Flashcards
An alpha particle contains
two protons and two neutrons
Alpha particles
Are emitted from the nuclei of heavy elements
Have greater mass than other particulate radiation
Have a positive charge
X-ray interaction with matter involves the transfer of energy from
Photon to matter
When comparing x-rays and gamma rays, a key distinction is in the
Origin of the emission
The quantity of x-rays or gamma rays required to produce a given amount of ionization in a unit mass of the air defines the
Roentgen
One joule of energy absorbed in each kilogram of material defines the
Gray
Sum of the weighted equivalent doses for all radiated tissues and organs is the
Effective dose
A device that is employed for detection and measurement of radiation exposure from x-ray radiation is called
Dosimeter
Ionization chambers work on the principle that when radiation interacts with the electrons in the air, ___ are produced
Ion pairs
Personal monitoring devices include
Thermoluminescent Dosimeter (TDL)
When no threshold dose for radiation exists, the effect is known as
stochastic
Deterministic effects of ionizing radiation include all of the following EXCEPT
a. sterility
b. cataracts.
c. skin erythema.
d. cancer.
cancer
Radiation exposure limits applicable to the protection of radiation workers are known as __________limits.
dose
Dose limits have been established for
Certain Organs
Certain Issues
The whole body
The cumulative effective dose limit for an occupational exposure to ionizing radiation is __________ mrem.
a. 5000
b. 500
c. 50
d. none of the above
D is correct
If the distance between the individual and the source of radiation is doubled, the exposure to the individual will be reduced by a factor of
4
Special gonadal shields should be employed any time the gonads are
within 5 cm of the primary beam
As the speed of the image receptor increases, patient dose
decreases
A fetus is most radiosensitive during __________ postconception.
8 to 15 weeks
The concept of ALARA
necessarily requires a benefit vs. risk assessment by the ordering physician.
Filtration permits the radiographer to ____ the photon emission spectrum into a more useful beam
narrow
The most common diagnostic x-ray beam filter material is what?
aluminium
The amount of material that will reduce the intensity of the primary beam to one-half its original value
half-value layer
If the half-value layer of diagnostic radiographic equipment is too low, it may be corrected by…
increasing the primary beam filtration
what term describes filtration that is part of the x-ray tube, the tube housing, and the collimation device
total
filtration that occurs as the primary beam passes through the glass window of the x-ray tube
inherent
The collimator device is considered part of what kind of filtration?
added
Which one of the following compensating filters is used most commonly in radiography of the femur?
a wedge filter
The thickest part of of the wedge filter should be placed on the ___ dense part of the patient
less
When comparing two x-ray beams, one at 60 kVp and the other at 85 kVp
Adding aluminum to the 60kVp beam greatly reduces the skin dose to the patient
The 85kVp beam will offer a lower entrance skin exposure
Adding 0.5mm of aluminum to the 85kVp beam will require no additional mAs in order to maintain beam intensity
