  Total-Body PET is one of the most promising medical diagnostics modalities.
The high sensitivity provided by Total-Body technology can be advantageous for
novel tomography methods like positronium imaging. Several efforts are ongoing
to lower the price of the TB-PET systems. Among the alternatives, the
Jagiellonian PET (J-PET) technology, based on plastic scintillator strips,
offers a low-cost alternative. The work aimed to compare five Total-Body J-PET
geometries as a possible next generation J-PET scanner design. We present
comparative studies of performance characteristics of the cost-effective
Total-Body PET scanners using J-PET technology. We investigated in silico five
Total-Body scanner geometries. Monte Carlo simulations of the XCAT phantom, the
2-meter sensitivity line source and positronium sensitivity phantoms were
performed. We compared the sensitivity profiles for 2-gamma and 3-gamma
tomography, relative cost of the setups and performed quantitative analysis of
the reconstructed images. The analysis of the reconstructed XCAT images reveals
the superiority of the seven-ring scanners over the three-ring setups. However,
the three-ring scanners would be approximately 2-3 times cheaper. The peak
sensitivity values for two-gamma vary from 20 to 34 cps/kBq. The sensitivity
curves for the positronium tomography have a similar shape to the two-gamma
sensitivity profiles. The peak values are lower compared to the two-gamma
cases, from about 20-28 times, with a maximum of 1.66 cps/kBq. The results show
the feasibility of multi-organ imaging of all the systems to be considered for
the next generation of TB J-PET designs. The relative cost for all the scanners
is about 10-4 times lower compared to the cost of the uExplorer. These
properties coupled together with J-PET cost-effectiveness, make the J-PET
technology an attractive solution for broad application in clinics.
