Paweł Moskal

The Modular J-PET represents the latest advancement in the Jagiellonian-PET series, utilizing extended plastic scintillator strips. This prototype's modular design enables cost-effective imaging of multi-photon annihilation and positronium, allowing for easy assembly, portability, and versatility. Additionally, its lightweight construction facilitates static bed examinations with a mobile detection system that can be positioned conveniently alongside the patient, negating the requirement for spacious clinical settings. Comprising 24 modules arranged in regular 24-sided polygons circumscribing a 73.9 cm diameter circle, each module integrates 13 scintillator strips, measuring 50 cm in length and 6 mm × 24 mm in cross-section. Scintillation light is captured at both ends through analog Silicon Photomultipliers (SiPMs). This research presents Sensitivity of the Modular J-PET tomograph, adhering to the NEMA_NU 2-2018 standards. Sensitivity measurement was performed with ⁶⁸Ge line source inside the 5 sleeves aluminium phantom placed at center of the detector`s field-of-view (FOV) and 10 cm offset from the center of detector. Analyzing the gathered data involved employing the specialized J-PET Framework software, developed within the C++ architecture. To validate the experimental findings, comparisons were made with GATE simulations, wherein the source and phantom were emulated in the same configuration as employed in the actual experiment. The system sensitivity of the Modular J-PET was assessed to be 1.03 0.02 cps/kBq in the center of the detector`s FOV with the peak sensitivity of 2.1 cps/kBq. However, the simulations indicate that at the center of the detector's FOV, the Modular J-PET achieves a system sensitivity of 1.32 0.03 cps/kBq, with a peak sensitivity of 2.9 cps/kBq.

Background Left bundle branch area pacing (LBBAP) is one of the methods to deliver conduction system pacing which potentially avoids the negative impact of conventional right ventricular pacing. Objective To assess echocardiographic outcomes in a long‐term observation in patients with LBBAP implemented for bradyarrhythmia indications. Methods and Results A total of 151 patients with symptomatic bradycardia and LBBAP pacemaker implanted, were prospectively included in the study. Subjects with left bundle branch block and CRT indications ( n = 29), ventricular pacing burden <40% ( n = 11), and loss of LBBAP ( n = 10) were excluded from further analysis. At baseline and the last follow‐up visit, echocardiography with global longitudinal strain (GLS) assessment, 12‐lead ECG, pacemaker interrogation, and blood level of NT‐proBNP were performed. The median follow‐up period was 23 months (15.5–28). None of the analyzed patients fulfilled the criteria for pacing induced cardiomyopathy (PICM). Improvement in left ventricular ejection fraction (LVEF) and GLS was observed in patients with LVEF <50% at baseline ( n = 39): 41.4 ± 9.2% versus 45.6 ± 9.9%, and 12.9 ± 3.6% versus 15.5 ± 3.7%, respectively. In the subgroup with preserved EF ( n = 62), LVEF and GLS remained stable at follow‐up: 59.3 ± 5.5% versus 60 ± 5.5%, and 19 ± 3.9% versus 19.4 ± 3.8%, respectively. Conclusion LBBAP prevents PICM in patients with preserved LVEF and improves left ventricle function in subjects with depressed LVEF. LBBAP might be the preferred pacing modality for bradyarrhythmia indications.