radiation and radiation dose Flashcards
What is RADIATION?
“the emission or transmission of energy in the form of waves or particles through space or through a material medium”.
BUT Radiation may also refer to the energy, waves, or particles being radiated.
electro-magnetic radiation radio waves, visible light, x-rays and gamma rays
particle radiation alpha, beta, and neutron radiation. Radioactive fission, fusion and decay
Ionising Radiation
Ionising is the process of “knocking” electrons from atoms. It is also capable of disrupting molecular bonds.
Exposure to ionising radiation can cause damage to living tissue resulting in mutation, cancer, radiation sickness and death.
Sources of Ionising Radiation
Background radiation
Artificial radiation
Internal Exposure
Ingestion of food or water that contain radionuclides or their decay products. Two most common are 40K and 14C.
Eating one banana you will consume approx. 0.1Sv dose.Potassium is most concentrated in skeletal muscle.Carbon is the building block of all cells and also is a component in DNA.
Cosmic Radiation
The earth is constantly bombarded by radiation from outer space as well as those rays interacting with atoms within our atmosphere
Medical Exposure
This is the largest controllable source of radiation exposure.
Remember this is only those modalities that utilise ionising radiation i.e. X-rays and gamma rays. So diagnostic, fluoroscopy, CT and Nuclear Medicine.
Consumer Products and Activities
Air Travel - flying increases the amount of Cosmic Radiation. Approx. 1 Sv per hour of flight.
Building Materials - many building materials contain radionuclides or their decay products. Brick, concrete and granite have much higher radiation than wood.
Smoking - Tobacco leaves contain 210Pb and 210Po. A one pack a day smoker is inhaling a whole body dose of approx. 0.36mSv of radiation pa.
DAP
dose area product.The results of a DAP meter can be changed by:
Altering technique factors – kVp, mA or time
Varying the size of the area of the exposed field
