PET List-mode Normalization

Hi All,

I’ve got a rather fundamental question with regards to sensitivity correction in PET list-mode reconstruction using CASToR.

My understanding is that, when PET list-mode data with normlization coefficients are to be used in CASToR, one must provide a separate normalization data file through the use of ‘-norm’. According to the benchmark bash script, the normalization data file “is a collection of all data channels where events can be recorded, with their associated normalization correction factors. It is used to compute the sensitivity image at the beginning of the execution”. This may be a naive question, but can someone please explain to me why we need a sensitivity image when a sensitivity coefficient is provided for each recorded list-mode event?

Thank you,

Hi Reza,

the computation of the sensitivity image is performed over all possible data channels (as you wrote yourself), and not only over non-empty data channels. By essence, the list-mode do not include empty (no recorded event) data channels (unlike histogram data).

Hope this helps,