Positron emission tomography (PET), an advanced diagnostic imaging technique, exploits the annihilation of positrons (e+) to delineate pathological alterations within diseased tissues. Integral to PET scanners are detector systems that transform gamma photons into fluorescent photons, thereby gleaning insights into the energy, time, and spatial distribution of gamma photons emanating from positron-emitting radiopharmaceuticals. Conventional PET scanners, bear a significant financial burden primarily due to their reliance on LSO (lutetium oxyorthosilicate) or LYSO (lutetium yttrium oxyorthosilicate) scintillation crystals. The exorbitant cost and limited availability of these crystal scintillators impede the widespread adoption of PET scanners. In a departure from conventional PET technology, the prototype J-PET scanner employed in this trial employs plastic scintillators, characterized by unique physical properties. This prototype is further equipped with bespoke software enabling three-photon imaging based on the annihilation of ortho-positronium (o-Ps) generated within diseased tissue. This study delves into the clinical applicability of PET scanners employing plastic scintillators, particularly investigating the feasibility of PET imaging using plastic scintillators where gamma quanta interact by mechanisms other than the photoelectric effect. Furthermore, this study endeavors to contemporaneously acquire and analyze data related to the lifetime of ortho-positronium (o-P) atoms emanating from routine radiopharmaceuticals. Additionally, it seeks to validate the utilization of a novel diagnostic indicator, termed the \"positron biomarker,\" through a prospective study, comparing its efficacy to conventional diagnostic PET scanning methodologies.