Radiation doses

Question 1

What is the average background radiation exposure per annum?

Answer 1

1-10mSv per year

Question 2

What is the radiation exposure of one mammogram? How does this compare to flying/plain films?

Answer 2

<0.4cGy (0.7mSv) per view - approximately the background radiation on a flight from LA to Auckland. Less radiation than a AXR

Question 3

What is the radiation exposure of 1 chest xray?

Answer 3

0.2mSv

Question 4

What is the radiation exposure of 1 abdominal xray? How does this compare to a chest Xray?

Answer 4

20mSv ie 100xCXR radiation

Question 5

What is the radiation exposure of a CT head?

Answer 5

2.3mSv

Question 6

What is the radiation exposure of a V/Q scan?

Answer 6

75mBq = 0.8mSv for perfusion phase. Add 1.6-3mSv if ventilation scan added

Question 7

1 bone scan

Answer 7

700mBq = 5mSv

Question 8

Give three common units for measuring radiation

Answer 8

milli seiverts
mega becquerel
Gray

Question 9

What is a becquerel?

Answer 9

A measure of radioactivity

Question 10

What do the units gray and seiverts measure?

Answer 10

Absorbed dose/dose equivalents of radioactivity

Question 11

What is the radiation exposure of an abdominal CT? What other CT exam is equivalent to this?
How does this compare to a CXR?

Answer 11

5-10mSv
Comparable to CTPA
Equal to approximately 800 CXRs

Question 12

What is the radiation exposure of a trauma CT?

Answer 12

3x trauma CTs = 40.2mSv check this

Question 13

By how much would you expect the incidence of cancer to increase per 1000 patients having 1 CT abdo each? What is the rate of fatal cancers from CT abdomens?

Answer 13

Approximately one additional cancer over the lifetime of those 1000 patients.
One additional fatal cancers per 1800 CT abdos of those

Question 14

By how much has the use of CT increased the rate of all cancers in the USA?

Answer 14

0.4% (NEJM 2007)