Nuclear Physics

Outcomes What are some of the other uses for radiation? What are the effects of radiation on humans? How can we measure exposure to radiation? What is the difference between absorbed dose and equivalent dose?

Uses for radiation Apart from bombs and power stations: Sterilise equipment and food Diagnose and treat diseases Monitor and control industrial processes

Uses: Sterilise equipment and food Radiation in high doses is lethal to bacteria Used to sterilise medical equipment and irradiate food

Uses: Diagnoses and treatment Radioactive sources enter the body intravenously or by mouth (called a tracer) Used to check blood flow, organ function and to look for infections

Uses: Diagnoses and treatment PET scan – positron emission tomography Allows for 3D imaging by tracking a tracer

Dangers of radiation Alpha and beta particles have ionising potential Any living tissue can be damaged by ionising radiation Low doses can cause cancer (by damaging cells) High doses (called acute exposure) causes radiation sickness and burns

Measuring Exposure Absorbed dose is the total amount of energy transferred to a given mass. Absorbed dose = E/m Units are gray (Gy) equivalent to J/Kg Equivalent dose is a qualitative measure, not quantitative Equivalent dose = absorbed dose x quality factor Units are sievert (Sv) equivalent to J/Kg