Registry Review

Question 1

What is a typical matrix for a ‘vanilla’ brain scan?

Answer 1

512 x 512

Question 2

What is a typical FOV for a ‘vanilla’ brain?

Answer 2

28cm or 280mm

Question 3

What is a typical slice thickness and interval (gap) for a ‘vanilla’ brain?

Answer 3

5mm / 5mm

Question 4

What would it take to really see the spinal cord well on a CT?

Answer 4

intrathecal contrast media

Question 5

Which branch of the common carotid artery will have sub branches that begin almost immediately?

Answer 5

External carotid

Question 6

What kind of a FOV would you use for a standard Chest CT?

Answer 6

36cm or 360mm

Question 7

What does the C-Spot-Run-In acronym stand for with abdominal arteries>

Answer 7

Celiac, Superior Messentaric, Renals, Inferior Messentaric

Question 8

What is a normal pulse rate?

Answer 8

60 - 100 BPM

Question 9

What is a normal range for pulse ox?

Answer 9

95% - 100%

Question 10

What is a typical MSAD amount for head scans:

Answer 10

50 mGy

Question 11

What is a typical MSAD amount for body scans?

Answer 11

30 mGy

Question 12

What other CT dose item is needed to calculate MSAD?

Answer 12

CTDI

Question 13

Will MSAD slightly over estimate or under estimate radiation dose?

Answer 13

it over estimates radiation dose

Question 14

What is a more realistic value for telling us about the total radiation scanned then CTDI or MSAD?

Answer 14

DLP or Dose Length Product

Question 15

What effect does decreasing slice thickness (collimation) have on pt dose?

Answer 15

It will increase patient dose because we will have to increase mAs to compensate for the increased noise.

Question 16

What is the dose in milliseverts for a chest x-ray VS a chest CT?

Answer 16

Chest x-ray is .05 mSv while a CT chest is over 5 mSv - The CT is nearly 100 times more radiation dose!

Question 17

Regardless of the number of detectors, what other factor limits the number of slices possible in a single rotation of the tube?

Answer 17

the number of ‘channels’

Question 18

What formula describes the attenuation of a homogeneous x-ray beam?

Answer 18

The Lambert-Beer Formula

Question 19

At high kVp, what is the most likely interaction?

Answer 19

compton

Question 20

What is the first thing to try when you get a ring artifact from a faulty (potentially mis-calibrated detector?

Answer 20

air calibration first. If that does not solve the problem, service might have to be called.