Within the framework of the 100µPET project, a SNSF-funded collaborative effort among the University of Geneva (UNIGE), the Federal Polytechnic School of Lausanne (EPFL), and the University of Luzern (UNILU), this work contributes to the development of a small-animal Positron Emission Tomography (PET) scanner aimed at pioneering ultra-high-resolution molecular imaging with the help of SiGe Bipolar Complementary Metal-Oxide-Semiconductor (BiCMOS) monolithic silicon detectors. The work done to study and optimize the scanner design within realistic engineering and budget constraints is presented in the thesis.

Monte Carlo simulations were conducted using the Allpix^2 framework, with large datasets generated to assess the effect of individual parameters.

Performance studies revealed that the pixel pitch could be increased up to 200 µm without significant degradation, with 90% of pixel clusters achieving a residual error within 200 µm from the expected interaction point.

Incorporation of high-Z absorber layers in the scanner improves sensitivity, which has been found to reach a peak value of 4.4% at the center of the field-of-view in a 60-layer configuration. Reconstruction studies conducted in collaboration with EPFL showed that the volumetric spatial resolution is expected to be below 0.02 mm^3, nearly an order of magnitude improvement over current preclinical systems.

In addition to the simulation and reconstruction studies, this thesis also presents results from module assembly characterization work and preliminary chip testing, providing a first experimental validation of the detector concept.

These results provide a solid basis for the continued development of the 100µPET scanner, guiding the mechanical and electronic construction to match the expected performance.