Principles of radiation safety

Question 1

What are the 3 principles of Radiation Safety?

Answer 1

Justification, optimisation and limitation

Question 2

Justification

Answer 2

no practice shall be adopted unless it produces
sufficient benefit to the exposed individuals or to society offset the radiation
detriment it causes – ‘to do more good than harm’.

Question 3

Optimisation

Answer 3

1. The magnitude of doses,
2. The number of people exposed, and
3. ALARA

Question 4

Optimisation Constraint

Answer 4

A source related restriction on the dose from an individual
source for planned exposures – an upper bound on the predicted dose.
- Always have to lower than limits
- 0.333mSv is the limit

Question 5

Reference level

Answer 5

a benchmark dose for a particular procedure to indicate whether, under routine conditions, a dose is unusually low or high.

Question 6

DRL

Answer 6

Diagnostic reference levels

presented in ARPANSA

Question 7

Limitation

Answer 7

places limits on the risk to individuals so
that
 risks do not exceed a value which is considered unacceptable for
everyday, long term exposure.

Question 8

Types of exposure

Answer 8

Planned, Emergency, and Existing

Question 9

Categories of exposure

Answer 9

Occupational, Medical and Public

Question 10

Planned exposure

Answer 10

involves deliberate introduction and operation of sources.
Involves anticipated exposures (normal exposures) and exposures that aren’t
anticipated (potential exposures).

Question 11

Emergency exposures‘

Answer 11

‘may occur during a planned situation, or from a
malicious act, or from any other unexpected situation, and require urgent
action to avoid or reduce undesirable consequences’.

Question 12

Existing exposure situations

Answer 12

already exist when a decision or control has to be

taken, including prolonged exposure situations after emergencies.

Question 13

Occupational exposures

Answer 13

incurred at work and as a result of knowingly

working directly with IR – exposed persons are typically monitored.

Question 14

Medical exposures

Answer 14

the exposure of patients as part of their diagnosis or

treatment

Question 15

Public Exposure

Answer 15

Covers all other exposures attained by the general public/environment

Question 16

Radiation Protection in Occupational and

Public Exposure

Answer 16

Requires that justification, optimisation and limitation be applied to each
practice

Question 17

Radiation Protection in Medical Exposure

Answer 17

Requires that justification, optimisation be applied, but not limitation.

Question 18

Occupational and public effective dose limits

Answer 18

20 mSv per year,
Averaged over a period
of 5 consecutive years - Occupational
1 mSv per year - Public

Question 19

Occupational equivalent dose limits on the lens of the eye, skin, hands and feet

Answer 19

lens - 150 mSv

skin, hands and feet - 500 mSv

Question 20

Public equivalent dose limits on the lens of the eye and skin

Answer 20

skin - 50 mSv

lens - 15 mSv

Question 21

Pregnant women in occupational exposure

Answer 21

.the radiation dose limit applying to the occupational exposure of a
pregnant woman to ionising radiation while involved in carrying out the
practice is a total effective dose of 1mSv per year

Question 22

Emergency Situations: Accidents dose limits

Answer 22

 Dose limits, as outlined in Schedule A, do not apply particularly in actions to
save lives or to bring the accident under control.

 However, individual exposures should not exceed the threshold for
deterministic effects.

 Once the emergency has been brought under control doses should be limited
as per practices i.e. Schedule A applies.