What safeguards are taken to prevent inadvertent irradiation in early pregnancy?
1) patient postings
3) elective booking
Radiographers use monitoring devices to record their monthly exposure to radiation. The types of devices suited for this purpose include the:
1) pocket dosimeter
2) thermoluminescent dosimeter (TLD)
3) optically stimulated luminescence dosimeter (OSL)
guidelines for the use of protective shielding state that gonadal shielding should be used
1) If the patient has reasonable reproductive potential
2)when the gonads are within 5cm of the collimated field
3) when tight collimation is not possible
A "controlled area" is defined as one:
1) that is occupied by people trained in radiation safety
2) that is occuped by people who wear radiation monitors
3) whose occupancy factor is 1
for each 1m = 1/1000 of its orig. int.
scatters 2 times before reaching operator
All of the following affect patient dose except:
A) inherent filtration
B) added filtration
C) source-image distance
D) focal spot size
D) focal spot size
Pocket Dosimeter- ionization chamber
how does the use of rare earth intensifying screens contribute to lowering the patient dose?
1) It permits the use of lower mAs
2) It permits the use of lower kvp
3) it eliminates the need for patient sheilding
beta, x, and gamma radiations
alpha are not strong enough
The advantages of beam restriction include:
1) less scattered radiation is produced
2) less biologic material is irradiated
3) less total filtration will be necessary
types of gonadal shielding include which of the following?
1) flat contact
2) shaped contact (contour)
all of the above
the law of bergonie and tribondeau states that cells are more radiosensitive if they are:
1) highly mitotic
3) mature cells
biologic material is most sensitive to irradiation under which of the following conditions?
which of the following most effectively minimizes radiation exposure to the patient?
A) small focal spot
B) low-ratio grids
C) long source-image distance
D) High speed intensifying screens
isotopes are atoms that have the same:
A) mass #, but a different atomic #
B) atomic #, but a different mass #
C) atomic # but a different neutron #
D) atomic # and mass #
which of the following accounts for the x-ray beam's heterogenity?
1) incident electrons interacting with several layers of tungsten target atoms
2) energy differences among incident electrons
3) electrons moving to fill defferent shell vacancies
all of the above
Diagnostic x-radiation may be correctly described as:
A) low energy, low LET
B) low energy, high LET
C) high energy, low LET
D) high energy, high LET
A) low energy, low LET
which of the following is a measure of dose to biologic tissue?
B) Rad (Gy)
C) Rem (Sv)
Protective devices such as lead aprons function to protect the user from
1) scattered radiation
2) the primary beam
3) remnant radiation
the operation of personnel radiation monitoring devices depends on which of the following?
Which of the following results from restriction of the x-ray beam?
1) less scatter radiation production
2) less patient hazard
3) less radiographic contrast
Early symptoms of acute radiation syndrome include
2) nausea and vomiting
which of the following statements is/are true with respect to radiation safety in fluoroscopy?
1. tabletop radiation intensity must not exceed 2.1 R/min/mA
2. tabletop radiation intensity must not exceed 10 R/min
3. in high level fluoroscopy, tabletop intensity up to 20 R/min is permitted
factors that determine the amount of scattered radiation produced include
1. radiation quality
2. feild size
the focal spot-to-table distance, in mobile fluoroscopy, must be
A) a minimum of 15 in.
B) a maximum of 15 in.
C) a minimum of 12 in.
D) a maximum of 12 in.
LET is best defined as
1. a method of expressing radiation quality
2. a measure of the rate at which radiation energy is transferred to soft tissue
3. absorption of polyenergetic radiation
in 1906, Bergonie and Tribondeau established their law, which states that cells are more radiosensitive if they
1. are young
2. are stem cells
3. have a low proliferation rate
1 and 2 only
has a HIGH proliferation rate
what is the effect on relative biologic effectiveness (RBE) as LET increases?
A) as LET increases, RBE increases
B) as LET increases, RBE decreases
C) as LET increases, RBE stabalizes
D) LET has no effect on RBE
Which of the following would most likely result in the greatest skin dose?
A) short SID
B) high kvp
C) increased filtration
D) increased mA
A) short SID
which of the following tissues or organs is the most radiosensitive?
C) small bowel
D) central nervous system
Stochastic effects of radiation are those that
1. have a threshold
2. may be described as "all-or-nothing" effects
3. are late effects
the photoelectric effect is the interaction between xray photons and matter that is largely responsible for patient dose. this effect is likely to occur under which of the following conditions? 1. w/ absorbers of high atomic #
2. w/ low-energy incident photons
3. w/ the use of pos. contrast media
which of the following factors will affect both the quality and quantity of the primary beam?
1. half-value layer (HVL)
radiation dose to personnel is reduced by which of the following exposure control cord guidlines?
1. exposure cords on fixed equipment must be very short
2. exposure cords on mobile equipment should be fairly long
3. exposure cords on fixed and mobile equipment should be of the coiled expandable
which of the following types of radiation is/are considered electromagnetic?
which of the following is/are associated with compton scattering?
1. high-energy incident photons
2. outer-shell electrons
3. characteristic radiation
which of the following cells are the most radiosensitive?
megakaryocytes- least sensitive
which of the following statements regarding the human gonadal cells is true?
1. the female oogonia reproduce only during fetal life
2. the male spermatogonia reproduce continuously
3. both male and female stem cells reproduce only during fetal life
in the production of characteristic radiation at the tungsten target, the incident electron
A) ejects an inner-shell tungsten electron
B) ejects an outer-shell tungsten electron
C) is deflected, with resulting energy loss
D) is deflected, with resulting energy increase
which of the following is/are composed of nondividing, differentiated cells?
1. neurons and neuroglia
2. epithelial tissue
biologic material irradiated under hypoxic conditions is:
A) more sensitive than when irradiated under oxygenated conditions
B) less sensitive than when irradiated under anoxic conditions
C) less sensitive than when irradiated under oxygenated conditions
D) unaffected by the presence or absence
patient exposure can be minimized by using which of the following?
1. accurate positioning
2. high kv, low mas factors
3. rare earth screens
all of the following statements regarding TLDs are true exept
A) TLDs are reusable
B) TLDs store energy
C) the TLDs response is proportional to the quantity of radiation received
D) following x-ray exposure, TLDs are exposed to light and emit a quantity of heat in response
D) following xray exposure, TLDs are exposed to light and emit a quantity of heat in response
- the TLDs are exposed to heat not emit heat
classify the following tissues in order of increasing radiosensitivity:
1. liver cells
2. intestinal crypt cells
3. muscle cells
types of secondary radiation barriers include
1. the control booth
2. lead aprons
3. the x-ray tube housing
all of the above
secondary radiation includes leakage and scatter
somatic effects of radiation refer to effects that are manifested
A) in the descendants of the exposed individual
B) during the life of the exposed individual
C) in the exposed individual and his or her descendants
D) in the reproductive cells of the exposed individual
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