Quantification in terms of Bq/ml is usually only performed by a solid state camera (rotating heads are not fast enough to pick up the dynamics involved). Using a DSPECT system with 99mTc-MIBI, peak myocardial activity concentration is on the order of 5 Bq/ml (with injection of 800 MBq), while of course the input function from the ventricle should be much higher. These numbers are patient-dependent, but are certainly on the order of Bq/ml for SPECT (only 2% of MIBI is taken up in the myocardium), even in PET studies a maximum of few hundred kBq/ml are to be expected (depending on tracer of course)

A recent paper from UCL in London explains myocardial perfusion quantification in SPECT further:

http://www.ncbi.nlm.nih.gov/pubmed/23578996

Hope it helps

In SPECT is not available to quantify in absolute measure. Only a relative (percentages) of injected dose is possible to quantify. In a practice, in stress study a 2.5 to 3.5 % of injected dose is uptake in myocardium. At rest, only 2 - 2.5 % is uptake in myocardium.

Quick comment on Jim's example using a D-SPECT: if one injects 800MBq and gets only 5Bq/ml in the myocardium, something went wrong. MIBI and similar agents have a poor extraction - but not THAT poor ;)

Oops - Stephen is correct, I'm missing a very important "k" in my value which should read 5 kBq/ml. I imagine 5 Bq/ml is pretty much undetectable!

are you (Jim and Stephan) talking about the time right after injection or after like an our after it? I need to know Bq/ml right after injection.

Hi, what do you mean with "right after in injection" ? Literally, zero. These tracers circulate in the blood for 1-4 min depending on their extraction from the blood to the myocardium. For the myocardium, there is a gradual increase before a stable state is reached after 3-5 min which is - as mentioned earlier - between 2-5% of the injected dose per heart . To get a feeling for the regional, absolute values as a function of time p.i., you might want to check a recent paper from R. Glenn Well in pigs (Doi: 10.2967/jnumed.114.139782)

Actually I am talking about the peak of the TAC (after wash-in and before wash-out) of myocardium. figure 3 in: Direct Least Squares Estimation of Spatiotemporal Distributions from Dynamic Cardiac SPECT Projections- 1999 - By:Rutter et al.

The uptake in myocardium in only 2-3%