Radiation Safety Flashcards
what are the 2 types of biological effects of radiation
deterministic and non deterministic
explain deterministic effects
effect will definitley occur at specific doses
what are acute deterministic effects
radiation sickness caused by 2-10 Sv to whole body
death caused by more than 10 Sv
what are chronic deterministic effects ?
hair loss, cataracts, sterility, obliterative endarteritis
explain non-deterministic effects
they occur at random therefore there is no threshold dose
can cause both somatic and genetic effects
dose of radiation does not correlate to amount of damage, however, there is less chance with a low dose
who is more susceptible to tissue changes when exposed to xrays ?
younger patients
what is the dose limit per annum for a classified worker?
20 mSv (used to be 50)
what is the dose limit per annum for a non-classified worker
6mSv (used to be 15)
what is the dose limit per annum for the general public
1mSv (used to be 5)
what is the recommendation of dose limitation for dentists
national radiology protection board - less than 0.1mV
SHOULD NEVER EXCEED 1mSv
what is the dose limit for patients
no set dose limit, just use ALARP!
how do we reduce radiation exposure
avoid unnecessary radiographs
use selection crieteria
use F film speed
high kV of machine, the lower the dose
collimating the beam
collimated DPT
ensure the machine is serviced
what is the intensity proportional to
1/distance squared - INVERSE SQAURE LAW
what law determines the size if the controlled area
the inverse square law
