Term
| how does radiation injury occur |
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Definition
| through absorption, the total transfer of energy from x ray photon to patient, chemical and biological changes |
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Term
| what are 2 specific mechanisms of radiation injury? |
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Definition
ionization
free radical formation |
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Term
| ionization is produced how? |
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Definition
| the photoelectric effect or compton scatter(outer shell electron ejected) |
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Term
| does ionization have little or much effect on cells? |
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Definition
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Term
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Definition
when xray photon ionizes water.
ionized water results in hydrogen and hydroxyl free radical.
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Term
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Definition
highly reactive unstable
uncharged nuetral atom that exists with a single unpaired electron in its outermost shell |
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Term
| what do free radicals do to achieve stability? |
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Definition
1. recombine witout causing damage
2. combine with other free radicals
3. combine with ordinary molecules and form toxin H2O2 (hydrogen peroxide cellular damage) |
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Term
| what are the theories that describe how radiation damages biological tissues? |
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Definition
Direct-x-ray photon directly hitting cell DNA-critical damage (this is not frequent)
Indirect-Xray photon absorbed within cell/free radicals comine forming toxins H2O2 (this happens more frequent because cells are 70-80% water. |
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Term
| what is the latent period in radiation biology? |
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Definition
| exoposure to x-radiation and clinical symptoms |
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Term
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Definition
is unstable and reactive
is an uncharged particle
has unpaired electron in outer shell
combines with molecules to form toxins
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Term
| Direct radiation injury occurs when? |
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Definition
| x-ray photon hit critical targets within cell (not frequent) |
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Term
| Indirect radiation injury occurs when? |
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Definition
| X-ray photons are absorbed and form toxins (more frequent because cells are 70-80% water) |
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Term
| what relationships describe the response of tissues to radiation? |
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Definition
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Term
| what are the factors that contribute to radiation injury? |
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Definition
-Total Dose
-Dose Rate
-Amount of Tissue Irradiated
-cell sensitivity
-age |
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Term
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Definition
after latent period this is usually minutes, days or weeks.
short term affects are associated with large amounts of radiation in a short period of time.
not usually related to dentistry
more of a ARS or atomic bomb situation |
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Term
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Definition
after years, decades, generations
associated with small amounts of radiation absorbed repeatedly over a long period of time.
related to induction of cancer, birth abnormalities, genetic defects |
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Term
tissue and radiation effects
Bone Marrow |
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Definition
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Term
tissue and radiation effects
reproductive cells (ova, sperm) |
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Definition
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Term
tissue and radiation effects
salivary gland |
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Definition
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Term
tissue and radiation effects
thyroid |
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Definition
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Term
tissue and radiation effects
skin |
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Definition
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Term
tissue and radiation effects
lens of eye |
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Definition
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Term
| radiation injuries that are not seen in the person irradiated but that occur in future generations are termed? |
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Definition
genetic effects
(not seen in person who was exposed but seen in offspring) |
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Term
| if a person has been irradiated and effects are seen like cancer, leukemia, cataracts this is termed? |
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Definition
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Term
which of the following is most susceptible to ionizing radiation?
a.bone tissue
b.small lymphocyte
c.muscle tissue
d.nerve tissue
e.eptithelial tissue |
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Definition
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Term
| the sensitivity of tissues to radiation is determined by? |
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Definition
cell differentiation
cell metabolism
mitotic activity |
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Term
which of the following is considered radioresistant?
a. immature reproductive cells
b.young bone cells
c.mature bone cells
d.epithelial cells
e. none of the above |
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Definition
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Term
| Radiosensitive is very sensitive to radiation. In order of how sensitive they are highest to lowest name these. |
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Definition
-small lymphocyte
-bone marrow
-reproductive cells
-intestinal mucosa
-skin
-lens of eye
-oral mucosa |
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Term
| radioresistant is resistant of radiation. name the cells that are radioresistant. |
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Definition
-muscle tissue
-nerve tissue
-mature bone/cartilage
-salivary gland
-thyroid
-kidney
-liver |
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Term
| an organ that if damaged diminishes the quality of life is termed? |
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Definition
critical organ
-those that are exposed during dental radiography are
-skin
-thyroid
-lens of eye
-bone marrow |
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Term
| a traditional unit for measuring x-ray exposure in air is termed? |
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Definition
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Term
| what are the two systems used for measurement? |
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Definition
old system Traditional
-R in air
-rad in tissue
-rem-product of absorbed dose
new system metric or international system (SI) |
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Term
| what is the radiation unit determined by quality factor (QF)? |
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Definition
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Term
| what are the units used in SI system? |
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Definition
coulombs/kilogram C/kg
Gray Gy
Sievert Sv
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Term
| traditional system measures in what ways |
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Definition
exposure (roentgen in air)
dose (rad in tissue)
dose equivalent (rem product) |
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Term
| the unit for measuring absorption of x ray is termed? |
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Definition
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Term
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Definition
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Term
| 1 rem = how many sieverts |
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Definition
1 rem=0.01 sv
1 sv=100 rems |
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Term
| what traditional unit of measure does not have an equivalent to to SI system? |
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Definition
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Term
| which unit of measure is only used for x-rays? |
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Definition
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Term
| what is the average dose of backround radiation recieved by and individual in us? |
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Definition
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Term
| what is the greatest contributor to artificial radiation exposure? |
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Definition
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Term
| the amount of radiation exposure an individual recieves varies depending on? |
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Definition
film speed
collimation
technique
exposure factors |
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Term
| a single intra oral radiograph (D speed film 70 Kvp,long PID) results in a mean surface exposure of? |
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Definition
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Term
| what is the dose where luekemia induction most likely occurs? |
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Definition
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Term
ARS
Acute Radiation Syndrome
nausea
vomitting
diarrhea
hair loss
hemorrhage |
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Definition
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Term
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Definition
| takes inner shell electrons out and are absorbed by patient |
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Term
| what effect is deterministicm meaning it can be predicted |
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Definition
non stochastic
cataracts
redness
side effects of radiation that can be predicted |
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Term
| what determines stochastic effects? |
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Definition
cancer/genetic mutations
probability increases with long dose |
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