RAD BIO test 2 Flashcards by Donovan Tompkins

what does LD x/y stand for?

LD= lethal dose
x= percentage of population
y== number of days it is measured
(how much lethal dose and how many days it will take to kill the population, LD 50/30)

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what are the orders for cell phases?

prophase
metaphase
anaphase
telophase

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what is dose response?

linear non-threshold assumes that any dose of radiation can cause damage
most late effects follow this dose response

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what is the most radiosensitive phase of a cell?

mitosis (division)

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what is Dose rate?
what happens to effect if dose rate goes up?

how quickly a dose is delivered
dose rate goes up, effect increases

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what is the law of Bergonie & Tribondeau?
Like?

cells are more sensitive if they are more primitive & prolific (lymphocytes)

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what is protraction?
if protraction goes up, what happens to effect?

how slowly a dose is delivered
protraction increases, effect decreases

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what is the most radioresistant cell phase?

mid to late S phase (DNA replication)

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what is interphase cell death?

several hundred Gray can kill a cell before it can divide

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what are somatic effects?
what two ways can this be measured in?

systemic effects of radiation to an individual
deterministic & stochastic

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what is deterministic?

biological effects that can be directly related to the dose received
threshold dose
occurs after a large dose of radiation
can occur in fluroscopy

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what is fractionation?
what happens to effect if fractionation increases?

delivering dose in discrete portions with a recovery period in between
fractionation increases effect deceases (90% repairable)

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what are deterministic early effects?
later effects?

Erythema (2Gy), epilation, infertility
(hours/days/weeks 90% repairable)
cataracts, temporary sterility (100 mSv)

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what are stochastic effects?
what type of effects?

randomly occurring biological effects of radiation
non-threshold
can happen in radiology (unlikely) probability increases with dose
late effect (cancer/ genetic abnormalities)

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what are teratogenic effects?
What are the by products of this?

occurs en-utero to a developing embryo or fetus
Congenital abnormalities, skeletal defects, & leukemia

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skeletal defects result during exposure at:

3rd week of gestation

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A ___ ____ embryo is ____ ____more sensitive to radiation than an adult

10-day
10 times

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how much of the skin exposure of the mother does the fetus receive?

1/3 (for abdomen)

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Leukemia results from exposure during:

mid-to late fetal growth

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Congenital abnormalities are likely caused by:

radiation (exposure) at 2-8 weeks

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Leukemia results from exposure during ___

mid-to late fetal growth

skeletal defects result during exposure at:

3rd week of gestation

how much of the mothers skin dose does a fetus receive on an abdomen x-ray?

1/3

A ____ day embryo is ___ times more sensitive to radiation than an adult

10
10

Genetic code consists of what?

a sequence of nitrogenous bases found in the DNA

how many pairs of chromosomes are there?

23 pairs

Transfer RNA (tRNA) is attached to a specific ___

amino acid

what is target theory?

certain molecules are critical to the survival of a cell

what is direct effects? Example?

x-ray photon deactivates a target molecule (x-ray photon directly damages a key gene of a chromosome) (deactivation of a target molecule from an x-ray photon)

what is indirect effect? What is most affected?

radiation ionizes water which in turn deactivates a target molecule most damage caused by this effect (cytoplasm of the cell)

what is a free radical?

any uncharged atom with a single unpaired electron in its outermost shell

what can be the end result of hydrolysis (radiation) of water?

hydrogen peroxide

what is the oxygen effect? What kind of hits?

tissue is more sensitive to radiation when irradiated in an oxygen rich environment (indirect hits)

what is acute radiation syndrome?

"radiation sickness" occurs after large doses of radiation over a short period of time

What are the 4 stages of acute radiation syndrome?

prodromal latent manifest illness death

Prodromal: side effects?

ARS within hours nausea, vomiting, diarrhea, & fatigue

Latent: symptoms?

1 week no symptoms, false sense of recovery

manifest illness:

less than 1 week syndrome effects

death:

instant or in some cases recovery with long-term effects/damage

what are the 3 main symptoms/syndromes?

hematopoietic gastrointestinal cerebrovascular

Hematopoietic syndrome: range? death? effects? who suffered early on?

1-10Gy death in 6-8 weeks decreased blood cells in bone marrow & body is susceptible to organ failure/infection early radiologists suffered from leukemia

what are the gastrointestinal sydromes:

6-10 Gy death in 4-10 days damage to epithelial cells that line the GI tract (inability to absorb nutrients) dehydration & severe diarrhea

what is the cerebrovascular syndrome? range? death? effects?

50Gy+ death in hours to 3 days fluid leaks into brain and intracranial pressure + central nervous system failure

what does LET stand for? what is it?

linear energy transfer the amount of energy deposited by radiation into a material per unit path or length

what is high LET? high LET= Example?

is low penetration (alpha particles) & high RBE Alpha particles

what kind of LET has high penetration?

low LET (Gamma & x-ray's)

low LET is associated with:

single strand DNA breaks

linear energy transfer of x-ray is low due to ___ ____

high penetration

High LET= Low LET=

low penetration (alpha particles) high penetration (gamma & x-ray)