Analytical modeling of the sensitivity of cylindrical PET systems based
on bulk materials and metascintillators
Abstract
Positron emission tomography scanners are commonly characterized by
their photon sensitivity. Scanner design often requires Monte Carlo
simulations to probe different geometries and materials. However, the
computational load of such simulations can be significant and costly.
Furthermore, the applicability of the Monte Carlo approach in
optimization loops is limited as each instance, such as source position
or scanner dimensions, has to be simulated independently.
In this work, Monte Carlo results have been accurately replicated by an
analytical model that uses characteristics of the foreseen cylindrical
scanner and returns the sensitivity profile following NEMA guidelines.
BGO and LYSO bulk materials and several metascintillator scenarios have
been used. The mean absolute error (MAE), mean absolute percentage error
(MAPE) and standard deviation of the error (SDE) are as low as 0.49%,
2.22% and 0.26% when no energy window is used, respectively. With an
energy window applied, the analytical model presents the lowest values
of MAE and SDE, with MAPE value being 8.19%. A normalization factor has
been used to compensate for the scattered events included in the 350-650
keV window. This work facilitates significantly the development of
cylindrical scanners, allowing direct probing of their axial sensitivity
profiles.