Radiation Safety COPY COPY Flashcards

1
Q

Radiation cataract

A

Considered deterministic effect in exposure of greater than 2 Gray
It may occur with lower doses, especially in those exposed to higher doses more frequently
Appears on posterior capsule of the lease
Up to 50% radiation workers have them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Absorbed radiation dose

A

Measure of deposited energy measures in Gray. One Gray is equivalent to energy deposition of one Joule per kilogram
Effective dose corrects for the different sensitivity of various tissues by multiplying the absorbed dose by the tissue weighting factor as well as correcting for the type of radiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Air kerma

A

Kinetic energy release Di matter

Energy released from a Xray beam in a small volume of air that isirradiated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Reference air kerma

A

Air kerma measured at a fixed point in space known as interventional reference point, 15 cm from isocenter on the X-ray tube side of the fluoroscope
May be used as a surpgrate for entrance skin dose
Immediately available st the end of the procedure and serves as best approximation of patient skin dose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Entrance skin dose

A

Measure of radiation that is absorbed by the skin at the site of Xray beam and skin interface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Dose area product

A

Also known as the kerma area product

Product of intensity of the radiation beam and the area of the beam

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Role of image intensifier

A

Detects the radiation rhat is transmitted through the patient and in turn allows for an image to be generated. The close the intensifier is to the patient the lower the dose required to generate and imaged and the lower the scatter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the main source of radiation to the operator and staff in radio suite

A

Scatter from the patient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What increases the radiation used

A

Geometric magnification
Fluorography such as digital acquisition
High frame rate

Pulsed fluoroscopy abd looped fluoroscopy decrease it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Signs of radiation skin injury and dose

A

Threshold is 2 Gray - transient erythema (several hours)
7 Gray - permanent epilating (several weeks after)
10 Gray - dermal athrophy (late effect with teleangiectasia formation)
Over 10 Gray - skin ulceration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Deterministic radiation effect

A

Effect that occurs at a specific threshold dose of exposure

Skin injury is the most common

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Relation of radiation scatter and distance

A

Scatter = 1/ distance square

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What’s the dose of radiation that’s dangerous in pregnancy

A

50 mGray is a concern

100 mGray May be grounds to termination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Current international commission of radiological protection recommendations for the occupational equivalent dose limit for the lease of the eye to prevent cataracts

A

20 mSv per year average over 5 years but not exceeding 50 mSV in a single year

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

If the operator is standing on the patients right side, what’s the tube position for LAO

A

X-ray tube near the patient and intensifier on the opposite side. Biggest scatter for the operator on the right side

Similarly - cranial angulation increases the scatter because the tube is near the operator and the intensifier is near the scull

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

When is patient follow up necessary for developement of skin injury following fluoroscopic procedure

A

When cumulative radiation dose exceeds 5G

dose over 2 G should be noted in the chart

17
Q

What’s is a stochastic effect

A

Includes changes in cells that can cause a neoplasm and heritable changes in reproductive cells
Can occur at any dose
Probability increases with increasing dose

18
Q

Radiation effective dose

A

Sum of the absorbed dose by various organs weighted by tissue factor based in their radio sensitivity
Used to determine gross estimation of the occurrence of stochastic risks in an average individual

19
Q

What radiation terms describe deterministic effect

A

Reference air kerma
Total fluoroscopy time
Kerma area product
Entrance skin dose

20
Q

How thick should the lead be

A

0.5mm

1mm for pregnant

21
Q

What is a radiation sentinel event

A

Doses from procedures at the same body area summer over 6-12 months, greater than 15 Gy

This need to be further investigated to determine Dskin max