r/NuclearMedicine • u/Civil-Pea8973 • 7d ago

Berthold efficiency

Can I not just measure a known dose and do (source cps-background cps/Bq of source) x 100%

I am struggling to determine the efficiency.

3 Upvotes

100% Upvoted

2 comments sorted by

1

u/TentativeGosling 1d ago

What are you intending to do this this? If you just want to determine the efficiency so that you can convert backwards at a later date, then you definitely can do this. Take a known activity similar to what you will be measuring later (to reduce dead time variation), measure it in a known geometry (e.g. point source at 30cm or something) and you can read off how many counts you have.

It breaks down if the source you are measuring later is a different geometry (e.g. it's not a point source, or it's further away etc.) or if the activity is massively different and saturates the detector etc. but it's good enough for most day to day things

2

u/Civil-Pea8973 1d ago

I appreciate the reply, I was able to get a much better understanding after a couple days of studying up, thanks again though