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Flashcards in 2 Radiation Safety Deck (11):
1

What are the 2 types of radiation?

1. ionising - radiation removes electrons from atoms to form ions (carcinogenic)

2. non-ionising - radiation cannot create ions but has thermal or photochemical effects

2

Application of ionising radiation?

IN VIVO:

Radiology (X-rays and CT(computed tomography)

Nucelar medicine

Radiotherapy

IN VITRO:

radio-labelled techniques

blood irradiation

3

Applications of non-ionising radiation?

MRI

UV therapy

Lasers

4

What is brachytherapy?

Using radioactive needles to direct radiation onto tumours

5

What is SPECT? How does it work?

Single photon emission computed tomography

Select a particle that will go to a specific area you want to look at.  Add a low damaging radioactive label to it.  You can now study the area. eg. flow rates in the kidney

6

What is PET/CT?

positron emission tomography and computed tomography
*high CT radiation dose

7

What is the unit describing radiation dose absorbed by an organ?

A Gray

This is a very large unit - a human would die within 30 days with an exposure of 10 Gray

We give tumours 80-100 Gray

8

What is the unit of effective dose?

Sievert (Sv)

Whole body acute lethal dose = 5-7 Sv

Annual background in Sydney = 2.3mSv

CT chest/abdo/pelvis = 20mSv

9

Describe the process of radiation interaction with the body

1. energy absorption and ionisation (~instantly)

2. interaction of ions with molecules and formaiton of free radicals (~instantly)

3. free radicals interact with molecules, cell and DNA (seconds)

4. Cell death, changes in DNA (minutes to years)

10

List 5 radiation protection precautions

1. Time - longer exposure, higher dose

2. Shielding - high density, thickness and atomic number required.  includes aprons, and walls (2mm lead radiography, 25mm lead PET, 2500mm concrete for radiotherapy)

3. Distance - decreases by 25% when you twice the distance

4.Personal monitoring - we use 20% of international annual limit doses (2x natural background radiation)

5. Radiation protection bodies sets regulations

11

What can go wrong with radiation?

Burns

Wrong patient, area, dose

Pregnancy - foetus  risk is of development problems or later life cancer