Lecture 2 Flashcards Preview

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Flashcards in Lecture 2 Deck (18):
1

What is the justification of a practice?

No practice shall be adopted unless it produces significant benefit to the exposed individuals outweighing the detriment the radiation causes

2

What should also be included in the justification of a practice?

Clinical evaluation, check required information regarding treatment

3

What are three considerations of the optimisation of a practice?

The magnitude of doses
The number of people exposed
Likelihood that the potential exposures will be kept ALARA

4

What is a constraint?

A source related restriction on the dose from an individual source for planned exposures- an upper bound on the predicted dose

Must not exceed 1/3 of limit

5

What is a reference level?

A benchmark dose for a particular procedure to indicate whether under routine procedures a dose is unusually high or low

Only applies to MI

6

What is a limitation?

Places limits on the risk to individuals so that

Risks do not exceed a value which s considered unacceptable

Involves all IR practices

7

Types of exposure

Planned- deliberate introduction involves normal exposures and potential exposures!!

Emergency-may occur in a planned situation or malicious act require urgent action to avoid

Existing- exist when a decision or control has to be taken including prolonged exposure after emergencies

8

Categories of exposure?

Occupational
Medical
Public

9

Radiation protection in occupational and public exposure involves?

Justification, optimisation and limitation and recommended dose limits

10

Radiation protection in medical exposure involves?

Justification, optimisation not limitation

11

effective dose for occupational and public exposure?


O-20mSv per year over a period of 5 consecutive years
P-1mSv

12

Equivalent dose for lens of the eye, skin and hands and feet?

O- lens:150 mSv
Skin:500 mSv
Hands and feet 500 mSv

P-lens:15 mSv
Skin:50 mSv

13

What are the dose limits?

1. Limits shall apply to the sum of the relevant doses in specified period and 50 ur committed dose up to age 70

2.shall not exceed 50mSv in a single year

3. Should not average 20mSv for 10 consecutive years

4.for public a higher value of effective dose can be allowed as long as over 5 years does not exceed 1mSv

5.equivalent dose to the skin applies to the dose averaged over any 1cm^2 of skin

14

What is the age limit for occupational exposure

Must be older than 16

15

Pregnant women and foetus exposure?

Total effective dose 1mSv

16

Dose limit to person assisting patient?

5 mSv per year
Does not apply if exposure is occupational

17

Do medical exposures have dose limits?

No

18

Dose limits in emergency situations?

No dose limit however individual exposures should not exceed threshold for deterministic effects