1. Barndioota consultative committee meeting

2. Radiation – What is it?
All living things rely on some form of radiation for their existence
Radiation is all around us all day, every day
It is the energy carried by either electromagnetic waves or moving particles

3. The electromagnetic spectrum
Cosmic rays from the sun have higher energies than gamma rays
Radiation may be non-ionising or ionising
The non-ionising radiation takes in the lower energies on the spectrum

4. Ionising radiation Can produce charged particles in matter Includes:
Cosmic rays
Gamma rays
X-rays
Alpha
radiation
Beta
radiation
Neutrons
We are surrounded by naturally occurring ionising radiation. This is called background radiation.

5. Background radiation
Where does it come from?

6. How is radiation measured?
Radiation can be measured in a number of different units
The most common is the Sievert (Sv)
1 Sv is a very large amount so usually the milliSievert (mSv) is used
1 Sv = 1000 mSv
Average background radiation in Australia is about 2mSv per year
Limits for people who work with radiation in Australia are 20mSv per year
Doses below 50mSv are regarded as low dose

7. Average annual doses from natural radiation sources
On a global scale it can be seen that Australia’s background radiation is relatively low

8. Radiation from medical procedures
Source
Typical Dose (mSv)
Equivalent period of natural background radiation
Chest X-ray
Dental X-ray
0.02
0.005
5 days
1.25 days
CT scans – head
– chest
– abdomen
2.6
8.0
13.0
1.7 years
5.3 years
8.7 years
Barium meal
2.5
1.6 years
Mammogram
0.4
13 weeks
Nuclear medicine scans
– bone scan
– thyroid
– liver
4.6
1.7
3.0 years
1.1 years
Note re nuclear medicine scans – it is worth pointing out to people that the benefit of having the scan far outweighs the risk from the increased exposure.

9. Radiation exposure and flying
Ionising radiation levels are higher in a flying plane than levels on the ground
At cruising altitudes exposure is greater than on the ground
Annual exposure to aircrew on domestic flights is around 1.8mSv above background
Aircrew on international flight routes receive around 4mSv extra per year

10. Radiation – alpha, beta, gamma
Type
What is it made of?
Reason the atom was radioactive
 alpha α
helium nucleus
Too large
 beta β e-
Too many neutrons e+
Not enough neutrons
 gamma γ
high energy
wave
Too much energy

11. Penetration of radiation
Alpha particles
Beta particles
Gamma rays
PAPER
ALUMINIUM
LEAD

12. Measuring the lifetime of a radioactive substance
Half-life
Measuring the lifetime of a radioactive substance
The time required for half of a given amount of a radioactive substance to decay
At start
After 1 half-life
After 2 half-lives
After 3 half-lives

13. Monitoring radiation levels in the workplace
All workers in a radiation environment wear these, or similar, devices to monitor their exposure

14. An important nuclear medicine
When we split uranium we make a smaller atom called molydenum-99. This is radioactive and can be used as a medicine.
How it works is we put the molybdenum in this pot here (pick up Gentech and point to vial) and send one of these to 250 hospitals around Australia each week. In the hospital the doctor will get the medicine out of the pot by pouring in some slightly salty water. The water which contains the medicine is then injected into the patient. They then have to lie really really still and go inside one of these big machines called a SPECT scanner.
What happens is that the medicine then breaks down, because it is radioactive and releases some radiation. The radiation is then picked up with a special camera called a gamma camera and colourful pictures of the body like these are made. This top picture shows inside a person’s brain and the bottom picture shows inside a person’s head and chest.
The doctor can look at these these pictures and see if there is something wrong with that person’s body. For example, if a person has a cancer lump somewhere the doctor will see it on the scan. Also, if there is something wrong with the brain or heart or lungs or bones the doctor will be able to see this too.

15. Thank you