Flashcards in Biological Effects of Radiation Deck (8)
What are the three electron interactions with matter?
What is the energy loss of an electron for each ionisation caused?
State and explain the three light production methods on irradiation.
fluorescence: prompt light emission
phosphorescence: delayed light emission
thermoluminescence: light emission when heated
Explain how indirect damage can arise from radiation.
Action of radiation leads to excited macromolecules (RH -> RH*) and then to the production of free radicals R• and H •
Which is more likely at diagnostic levels: direct or indirect action?
Define Linear Energy Transfer (LET)
LET is a measure of the rate at which energy is transferred to the medium (i.e. ionisation density along the track of the particle)
A more penetrating beam has a lower LET
Define Radiobiological Effectiveness (RBE)
RBE = dose of 200kVp x-rays/dose of other radiation to give same biological effect