4.4.2.4 Radioactive contamination

what can ionising radiation do

increase the risk of cancer in humans

irradiation

exposing an object to nuclear radiation (alpha, beta, gamma or neutrons)

\
o Lasts only for a short period of time

o The source emits radiation, which reaches the object  Exposing an object to nuclear radiation, but does not make it radioactive

o E.g. radioactive dust emitting beta radiation, which “irradiates” your skin o Medical items are irradiated sometimes to kill bacteria on its surface, but not to make the medical tools themselves radioactive

uses of irradiation

sterilisation- objects that cannot be heated

place object to be sterilised into a wrapper to stop bacteria entering

place object near a radioactive isotope that emits gamma radiation

that’s inside a lead shield to protect workers from radiation

withdraw internal shield allowing gamma radiation to irradiate the object

the gamma radiation kills any bacteria present

when an object is irradiated like this the object does not become radioactive- that’s because the object comes into contact with the radiation but nit the radioactive isotope itself

precautions when working with radioactive isotopes

shielding to stop radiation

gloves can protect against alpha radiation as it has a low penetrating power

use a lead apron for beta and gamma radiation as they are more penetrating

led walls, screen made of led-glass

radiation monitor- can measure how much radiation has been received, if the person has received too much radiation, we can stop them from working with radioactive isotopes

what is radioactive contamination

when unwanted radioactive isotopes end up on other materials, this is called contamination

hazardous as the radioactive atoms decay and emit ionising radiation

\
o Lasts for a long period of time

o The source of the radiation is transferred to an object  Radioactive contamination is the unwanted presence of radioactive atoms on other materials – the hazard is the decaying of the contaminated atoms releasing radiation o E.g. radioactive dust settling on your skin (your skin becomes contaminated)

alpha radiation

can be very dangerous- strongly ionising but easily stopped by dead cells on the skin surface. Alpha emitters can be dangerous if inhaled or swallowed (dust or food)

alpha particles crash into living cells and damage dna

beta radiation

quite ionising and can penetrate skin into the body

gamma radiation

weakly ionising. can penetrate body but likely to pass straight through

peer review

Scientific Reports Published need to be peer reviewed

If they are on the effects of radiation on humans, peer review is essential

If initial studies got measurements wrong, safety levels based on the study may cause people to die.

summary