Xray, US, CT, MRI

Question 1

What is latent effect?

Answer 1

Effect of radiation does not show up straight away

Question 2

What is cumulative effect?

Answer 2

Repeated, long term exposure of radiation building up effects

Question 3

Effects of radiation

Answer 3

Somatic- positive (cancer), negative (burns)
Carcinogenic- leukemia
Genetic - gonad mutations
Stochastic- occur by chance, random, no threshold
Non-stochastic- dose specific threshold

Question 4

IRR (2017, 1999)

Answer 4

Keep radiation exposure to a minimum
Do not exceed dose limits
Clinical reason to x-ray

Question 5

How often to service Xray?

Answer 5

Annual by external company

Question 6

What is an RPA?

Answer 6

Radiation protection advisor - certificate holder, external, advises safe working conditions, ensure practice follows IRRs, control area, restrict exposure

Question 7

What is a RPS?

Answer 7

Radiation protection supervisor- designated person in practice (head RVN, head vet), supervise Xray , ensure local rules followed

Question 8

Xray warnings

Answer 8

1. Controlled area - area around primary beam identified by RPA & RPS, clearly marked, before exposure: warning light, do not enter sign, door, 2m away from beam or lead screen
2. Signage- radiation warning, red light when on
3. Siren- beep during exposure

Question 9

Written local rules

Answer 9

By RPA
Ensure safety
Specific to practice & their Xray
Name & address, RPS, maintenance & reporting faults, IRR, authorised personnel, guide to Xray

Question 10

ALARA

Answer 10

Radiation As Reasonably Low As Achievable - clinical indication, restraint, positioning aids, controlled area, off after Xray

Question 11

maximum permitted dose MPD

Answer 11

Measured in millisieverts (mSv) per year

• vet = >2msv
• pregnant or 16-17yo = >1msv
• public= >0.3msv

•level for investigation = 15-20 MSV

Question 12

Dosimeter

Answer 12

Measures radiation exposure
Worn: trunk, chest, waist, under lead gown, collar, sleeve

① film - blue with Xray film & metal, film processed after and dose calculated
② thermoluminescent- purple/orange with lithium fluoride crystals, stores energy = measured by heating

Store away from radiation
1-3 month checked
Lost/damaged
RPS

Question 13

Stochastic effects of radiation?

Answer 13

Random, occur by chance
Eg neoplasia, genetic mutation

Question 14

Non- stochastic effects of radiation.

Answer 14

Occurs after dose specific threshold as been met
Eg acute radiation burns

Question 15

What information should be recorded on the exposure chart?

Answer 15

Kv
MAS
FFD
grid
body part
position
patient name & weight
initials
comment on quality

Question 16

How far away from the primary beam should you be?

Answer 16

2m unless behind lead wall