Radiation Flashcards
where does most exposure come from?
Natural sources, radon
when were X-rays discovered and by whom?
Roentgen in 1895
who discovered that uranium salts emit ionising radiation?
Becquerel in 1896
what cells are more sensitive to ionising radiation
undifferentiated cells
what tissues are more sensitive to ionising radiation
young tissues
Are tissues/cells with higher or lower metabolic activity more sensitive to ionising radiation?
higher
are cells that divide faster more sensitive to ionising radiation?
yes
who showed that ionising radiation was mutagenic
Muller
when was it discovered that radiation could cause hydrolysis of water and generation of free radicals
1940s
what was the result of Chernobyl
Increase in cases of thyroid cancer
what area was first to be struck by a nuclear strike
hisoshima
how do we gather information of the effects of health risk of ionising radiation
survivors
what four ways can we gather info on effects of ionising radiation
survivors
medical exposure
ionising exposure
environmental exposure
in what country is there high enivronmental exposure to radiation
Ramsar, Iran
why dont people develop cancer early in their lives
presence of antioxidants
what does 1 gray stand for
1 joule of energy absorbed per kg of tissue
define linear energy transfer
the rate of transfer to a tissue
characteristics of molecules with high energy transfer
- interact with water very quickly
- deposit energy very quickly over short track
- intense
which radiation has a low energy transfer
X-rays and gamma rays
characteristics of molecules with low energy transfer
- less likely to interact with water
2. can go through cells without depositing any energy
How to work out Sievert
1 Grey x waiting factor
two categories of ionising radiation
- deterministic
2. stochasitc
three examples of deterministic radiation
- radiation sickness
- damage to skin
- cataracts
how does deterministic differ from stochastic
With deterministic as dose increases so does the severity and frequency. Whilst with stochastic severity dose not increase with dose
example of stochastic
genetic damage and cancer
what four areas does acute exposure to radiation have an effect on ?
- skin
- reproductive system
- digestive
- cytogeneic
what are the long term effects of radiation exposure? (4|)
- eyes
- damage to immune system
- cancer
- foetus
what are the four most common cancers due to radiation exposure
- breast
- thyroid
- leukemias
- alimentary tract
what did Muller show in 1927 regarding flies
ionizing radiation is mutagenic to flies
how does oxygen effect cell killing
it increases it
what does exposure to radium-based paints result in
condition similar to ‘phossy jaw’
how are we exposed to polonium-210
through radioactive decay of radon-222
is radiation-induced genetic damage a stochastic or deterministic effect
deterministic
is radiation-induced cancer a stochastic or deterministic effect
stochastic
do radiation-induced cancer have a lag period
yes, several years
what does radiation-induced radiolysis cause
generation of reactive oxygen species
what is more likely to cause radiation-induced radiolysis
alpha-particles
what does radiation-induced radiolysis of water produce
hydroxyl radicals, 2 which form hydrogen peroxide
what does decaying of U-238 produce?
Rd-226
what does Rn-222 emit
LET radiation
where in England is exposure to Rn-222 highest
Cornwall and Devon
what does Radon-222 increase risk of
lung cancer
what two things increase the risk of bone cancer
stronium-90 and Caesium-137
what increases the risk of thyroid cancer
iodine-131
what three things does the law of Bergonie and Tribondeau state
- stem cells more radiosensitive than mature
- tissues with highest cell turnovers more sensitive
- adult tissues/organs less sensitive
when are children irradiated in utero more likely to have impaired cognitive function
4 to 20 week
what can exposure to radiation in utero result in
prenatal death
when can childhood leukemi aoccur
from in utero irradiation at any stage in gestation
when is incidence of congenital abnormalities most frequent
following exposure during the period of organogenesis
what is radon
radioactive gas
who is radon hazardous to
uranium miners
where is radon most commonly found
underlying rock is granite
can you survive doses of 100 gy
no
what do doses of 10 to 50 gy do to the GI tract
cause irreversible damage
what do doses of 2 to 5 cause
radiation sickness
what does 2 to 5 gy effect
haemoatopoietic system
