Radiation Safety Flashcards
Which has a higher dose xray or CT
CT
What is the average patient dose
10-20 mSv
More detail requires what
More photons
Will all tissue receive the same exposure
Yes
What does a multi slice CT scan do
Scans and overlaps areas
Multi slice CT scan gives greater …….
Detail and dose
What is pitch
Relationship between scan / slice width
Tube rotation
What does it mean if the pitch is 1
Table and tube moved at the same time
No missing info
Overlapping info
What does it mean if the pitch is less than 1
Table moves MORE than scan width
Stretched coil
Missing info
What does it mean if the pitch is greater than 1
Table moves LESS than scan width
Small coils
What is the relationship of slice thickness if the pitch is less than 1
Slice thickness is larger than the patient movement
What will be the dose for thicker & fewer slices
Less patient dose & less detail
What happens if you increase pitch
Less image resolution
Less patient dose
Using a high kV results in
Lower mA
Less patient dose
Should you shield in CT
Yes
What is reducing scan FOV
Similar to collimating
How do you reduce exposure to eyes
Angle gantry to match skull base
Why do you use a power injector
To avoid manual administration of contrast
