Lange Q&A flashcards
6 (70) equipment & QC
For what reasons is tungsten (W) the target material of choice?
what device functions to rotate the anode?
how do the actual and effective focal spots differ in size?
high atomic number (Z), high melting point, and high thermal conductivity
the induction motor
the effective focal spot (small: 0.5mm-1mm, large: 1mm-2mm) is smaller than the actual focal spot (small 1cm Large: 1.5cm-2cm)
1 (7)
somatic effects that occurs within minutes, hours, days, or weeks after initial irradiation are termed ___
what minimum radiation dose is required in order for acute radiation syndrome to occur?
the latent period (in ARS) decreases as radiation exposure _____
early or short term effects
1 Gy
increases
1 (6)
radiation-induced biologic damage to living organisms is termed ____ effects
non-stochastic effects may also be referred to as __ effects
what are the limits for these:
Lens of the eye:
embryo/fetus:
thyroid:
skin, hands, & feet:
gonads:
somatic
deterministic
150 msv
0.5msv
500 msv
500 msv
50 msv
1 (8)
how does oxygenation affect cell/tissues radiosensitivity?
what is the LD 50/30 for adult humans?
the presence of oxygen increases cell/tissue radiosensitivity
300-400 rad (3-4 Gy)
1 (9)
A dose of 200 rad (2 Gy) to skin can cause a radiation-induced reddening termed ____
ionizing radiation-induced hair loss is termed ____
what is the name of the particularly radiosensitive male sex cell?
erythema
epilation or alopecia
spermatogonia
1 (10)
what is the target organ believed to be responsible for radiation-induced leukemia?
what radiation exposure dose to the ovaries will result in temporary infertility?
in which portion of pregnancy is the embryo/fetus most radiosensitive?
bone marrow
200 rad or 2 Gy
the first trimester
1 (13)
List the four types of late effects of ionizing radiation exposure:
what skin layer is most radiosensitive?
carcinogenesis, cataractogenesis, embryological effect, and lifespan shortening
basal cell
1 (11)
what is defined as “the estimated dose to the gonads that, if received by the total population gene would produce total genetic effect on the population as the sum of the individual doses actually received?
what are the three guidelines for determining when the gonads should be shielded?
what three parts of the body should be shielded from the useful beam whenever possible?
genetically significantly dose (GSD)
when the gonads are within 5cm of the collimated primary beam, when the patient is of reproductive age and when clinical objectives permit
the lens of the eye, the breasts, the reproductive organs
1 (12)
when a 1-mm Pb flat contact shield is used to shield female reproductive organs, their dose is reduced by about how much?
when a 1-mm Pb flat contact shield is used to shield male reproductive organs, their dose is reduced by how much?
50%
90% to 95%
1 (14)
which are the two interactions between x-ray photons and tissue cells that occur most often?
which of the major interactions between x-ray photons and tissues cells occurs with high-energy photons?
which of the major interactions between x-ray photons and tissue cells is most likely to occur with tissues having high atomic number?
which of the major attractions between x-ray photons and tissues cells results in total absorption of the incident photon?
Compton scatter & photoelectric absorption
Compton scatter
photoelectric effect
photoelectric effect
1 radiation protection (3)
what is the cellular component having the greatest radiobiological significance?
what effect does the presence of oxygen have of radiosensitivity?
which of the following ionizing radiations has the highest LET? (alpha, beta, gamma)
DNA
oxygen increases radiosensitivity
Alpha
1 Rad protection (15)
which of the major interactions between x-ray photons and tissue cells is a major contributor to patient dose?
which of the major interactions between x-ray photons and tissue cells predominates in the diagnostic x-ray range?
which of the major interactions between x-ray photons and tissue cells is responsible for scattered radiation fog?
which of the major interactions between x-ray photons and tissue cells poses a radiation hazard to personnel?
photoelectric effect
Compton scatter
Compton scatter
Compton scatter
1 radiation protection (17)
which interaction between x-ray photons and matter involves an outer shell electron and only partial transfer of energy?
which interaction between x-ray photons and matter involves a low-energy (low KV) incident photon?
which interaction between x-ray photons and matter is most damaging to the diagnostic image?
which interaction between x-ray photons and matter involves the greatest patient dose?
Compton scatter
photoelectric effect
Compton scatter
photoelectric effect
1 Radiation protection (16)
how does Compton scatter physically look?
what kind of incident photon energy is involved?
with what frequency does this interaction occur in comparison to other types of interactions between x-ray photons and matter?
*
high energy
Compton scatter occurs most frequently
1 radiation protection (18)
which interaction between x-ray photons and matter occurs least often and is the only interaction that does not cause ionization?
which interaction between x-ray photons and matter involves a recoil electron?
which interaction between x-ray photons and matter is most likely to occur in high density tissues like bone?
what is the name given to an ejected electron in a Compton interaction?
coherent scatter (unmodified scatter)
Compton scatter
photoelectric absorption (effect)
recoil electron
1 radiation protection (19)
which interaction between x-ray photons and matter involves most potential radiation hazard to personnel?
which interaction between x-ray photons in matter produces a characteristic ray?
which interaction between x-ray photons and matter is more likely to produce short scale contrast?
compton scatter
photelectric effect
photoelectric effect
1 radiation protection (4)
what is the term used to describe the human sequence of events following high-level radiation exposure, and leading to death in a short time?
list the three major types of acute radiation syndromes:
which of the three types of ARS requires the least amount of ionizing radiation dose to occur?
what are the weighting factors of Gamma, x-ray, Alpha?
Acute radiation syndrome (ARS)
hematological, gastrointestinal, and cerebrovascular (central nervous system CNS)
hematological
1,1, & 20
1 radiation protection (1)
what type of dose-response relationship is characterized by an early response to a high-dose exposure?
what type of dose-response relationship is characterized by a late response to low-dose exposures?
what is described as a measure of the rate at which energy is transferred from ionizing radiation to soft tissue?
deterministic (non-stochastic)
stochastic (probabilistic)
LET (linear energy transfer)
1 radiation protection (2)
what are two examples of radiation-induced conditions that follow a linear non-threshold dose-response relationship?
skin effects that result from fluoroscopic exposure follow what type of dose-response relationship?
what type of effects are described as: “those biologic somatic effects of ionizing radiation that exhibit a threshold dose below which the effect dose not normally occur and above which the severity of the biologic damage increases?
genetic effects, radiation-induced cancer, leukemia
non-linear (sigmoid), threshold dose response
deterministic (nonstochastic)
1 radiation protection (20)
what component of personal dosimeters functions to evaluate radiation quality?
which of the following three types of personal radiation monitoring devices is most sensitive? TLD, OSL, or film badge?
what are the two weighting factors that are used to determine the sievert?
filters
optically stimulated luminescence dosimeter
Wt & Wr
