MOD 2 - Radiation Exposure Context

ionizing radiation

type of energy released by atoms that travels in the form of electromagnetic waves

types of non-ionizing electromagnetic radiation

• UV light

• visible light

• infrared light

• microwaves

• radio waves

types of ionizing electromagnetic radiation / low LET

• x-rays

• gamma rays

particulate ionizing radiation types

• alpha particles

• gamma radiation

• beta particles

• neutrons, protons, electrons

Sources of radiation exposure

• natural

• man-made

natural radiation sources

• earth/soil: uranium, potassium, thorium

• cosmic: radiation from outer space

• gamma rays:

  • decay of radioactive atom

  • lighting

  • cosmic rays

  • radon gas

• human body

• radon and thoron: gas released from the decay of Ur and thorium

man-made radiation sources

• nuclear

• medical

• industrial

eg. industrial sources

• uranium mines

• nuclear power plants

• smoke detectors

classification of radiation exposure

• occupational = work/job

• medical = exams for care and diagnosis

• public/background = where you live, lifestyle

largest contributors of radiation exposure

• medical radiation - CT

• background - Radon and Thoron

LET

• linear energy transfer

• a measurement of how much ionizing radiation energy transfers to tissue per unit length

• lower LET = fewer interactions with cellular DNA, lowering the chance of damage to genetic material

factors of biological effects related to radiation exposure

• dose magnitude

• whole or partial body

• age: younger pple are more sensitive to radiation

• gender: women are more susceptible to negative health effects as they have more reproductive tissue

• bmi: more obese = need higher radiation dose for clear image

early effects are within

hours to months

early effect only occurs to

• large, whole body dose

• nuclear events

radiation response in early effects

• acute radiation sickness

• early somatic effects

• deterministic effects

late effects occur to

low dose exposure to ionizing radiation

late effects show

after years or not at all

radiation response in late effects

• carcinogenesis (high dose, whole body)

• late tissue reactions (cataract)

• birth defects

units of exposure

• grays (gy) = for intensity/measurement of ionizing radiation

• sieverts = potential damage/risks to biological tissue caused by exposure