Phantom imaging demonstration of positronium lifetime with a long axial field-of-view PET/CT and I.

Purpose: Measuring the ortho-positronium (oPs) lifetime in human tissue bears the potential of adding clinically relevant information about the tissue microenvironment to conventional positron emission tomography (PET). Through phantom measurements, we investigate the voxel-wise measurement of oPs lifetime using a commercial long-axial field-of-view (LAFOV) PET scanner.

Methods: We prepared four samples with mixtures of Amberlite XAD4, a porous polymeric adsorbent, and water and added between 1.

Nonmaximal entanglement of photons from positron-electron annihilation demonstrated using a plastic PET scanner.

In state-of-the-art positron emission tomography (PET), information about annihilation photon polarization is unavailable. Here, we present a PET scanner built from plastic scintillators, where annihilation photons primarily interact via the Compton effect, providing information about both photon polarization and propagation direction. Using this plastic-based PET, we determined the distribution of the relative angle between polarization planes of photons from positron-electron annihilation in a porous polymer.

Echocardiographic response from left bundle branch area pacing optimized cardiac resynchronization therapy (LOT-CRT) vs traditional CRT.

Background: Traditional cardiac resynchronization therapy (CRT) with biventricular pacing (BVP) may be less effective in patients with nonspecific intraventricular conduction delay (NIVCD). Left bundle branch area pacing (LBBAP) combined with left ventricular (LV) coronary venous lead pacing (LOT-CRT) may be more effective in these patients.

Objective: We assessed the echocardiographic response of LOT-CRT in patients with left bundle branch block (LBBB) or NIVCD and compared it with a propensity-matched BVP cohort.

Real-time antiproton annihilation vertexing with submicrometer resolution.

Primary goal of the AEḡIS experiment is to precisely measure the free fall of antihydrogen within Earth's gravitational field. To this end, cold (≈50 K) antihydrogen will traverse a two-grid moiré deflectometer before annihilating onto a position-sensitive detector, which shall determine the vertical position of the annihilation vertex relative to the grids with micrometric accuracy. Here, we introduce a vertexing detector based on a modified mobile camera sensor and experimentally demonstrate that it can measure the position of antiproton annihilations within [Formula: see text] μm, a 35-fold improvement over the previous state of the art for real-time antiproton vertexing.

Realistic total-body J-PET geometry optimization: Monte Carlo study.

Background: Total-body (TB) Positron Emission Tomography (PET) is one of the most promising medical diagnostics modalities, opening new perspectives for personalized medicine, low-dose imaging, multi-organ dynamic imaging or kinetic modeling. The high sensitivity provided by total-body technology can be advantageous for novel tomography methods like positronium imaging, demanding the registration of triple coincidences. Currently, state-of-the-art PET scanners use inorganic scintillators.

First Stability Characterization for a CZT Detection System in an ee Collider Environment.

The SIDDHARTA-2 collaboration has developed a novel X-ray detection system based on cadmium-zinc-telluride (CZT, CdZnTe), marking the first application of this technology at the DAΦNE electron-positron collider at INFN-LNF. This work aims to demonstrate the stability of the detectors' performance in terms of linearity and resolution over short and long periods, thereby establishing their suitability for precise spectroscopic measurements within a collider environment. A reference calibration spectrum is presented in association with findings from assessments of linearity and resolution stability.

Total Body PET/CT: Clinical Value and Future Aspects of Quantification in Static and Dynamic Imaging.

Total body (TB) Positron Emission Tomography (PET) / Computed Tomography (CT) scanners have revolutionized nuclear medicine by enabling whole-body imaging in a single bed position. This review assesses the physical and clinical value of TB-PET/CT, with a focus on the advancements in both static and dynamic imaging, as well as the evolving quantification techniques. The significantly enhanced sensitivity of TB scanners can reduce radiation exposure and scan time, offering improved patient comfort and making it particularly useful for pediatric imaging and various other scenarios.

Novel approach to left bundle branch area pacing lead implantation using a 3-dimensional stylet.

Background: Left bundle branch area pacing (LBBAP) requires implantation of the lead deep in the interventricular septum. We developed a novel implantation method that does not require dedicated delivery catheters but only a manually shaped 3-dimensional (3D) stiff stylet.

Objective: The aim of the study was to characterize procedural outcomes of this technique when used as a routine approach for LBBAP.

Global R-wave peak time for diagnosis of left bundle branch capture.

Background: QRS axis deviation and rS configuration in V6 affect the ability of V6 R-wave peak time (RWPT) criterion to discriminate capture type during left bundle branch area pacing (LBBAP).

Objective: We hypothesized that combining RWPTs from lateral leads: I, aVL, V5, and V6 may better reflect left ventricular activation time and that such a global RWPT may be insensitive to changes in QRS configuration.

Methods: The analysis included 519 electrocardiograms (ECGs) with nonselective left bundle branch pacing (nsLBBP) and 176 ECGs with left ventricular septal pacing (LVSP).

Transseptal Transition Patterns During Left Bundle Branch Area Lead Implantation.

Background: Continuous deep septal pacing and signal recording during implantation of left bundle branch pacing (LBBP) lead enables to monitor beat-to-beat changes of electrocardiogram (ECG) and myocardial current of injury (COI) as the lead crosses the septum.

Objectives: This study aimed to characterize patterns of continuous QRS, ST-T, and COI change for monitoring of the lead depth and instantaneous determination of the obtained capture type (LBBP vs left ventricular septal pacing [LVSP]).

Methods: The ECG and COI during lead implantation were scrutinized for sudden changes of V R-wave peak time, V initial and terminal R-wave amplitude, V-V R-wave amplitude, repolarization pattern and S-wave amplitude in I, V-V, and COI drop.

Conduction system pacing compared with biventricular pacing for cardiac resynchronization therapy in patients with heart failure and mildly reduced left ventricular ejection fraction: Results from International Collaborative LBBAP Study (I-CLAS) Group.

Background: Cardiac resynchronization therapy (CRT) is a guideline-recommended therapy in patients with heart failure with mildly reduced ejection fraction (HFmrEF, 36%-50%) and left bundle branch block or indication for ventricular pacing. Conduction system pacing (CSP) using left bundle branch area pacing or His bundle pacing has been shown to be a safe and physiologic alternative to biventricular pacing (BVP).

Objective: The aim of this study was to compare the clinical outcomes between BVP and CSP for patients with HFmrEF undergoing CRT.

Positronium image of the human brain in vivo.

Positronium is abundantly produced within the molecular voids of a patient's body during positron emission tomography (PET). Its properties dynamically respond to the submolecular architecture of the tissue and the partial pressure of oxygen. Current PET systems record only two annihilation photons and cannot provide information about the positronium lifetime.

Positronium lifetime validation measurements using a long-axial field-of-view positron emission tomography scanner.

Background: Positron emission tomography (PET) traditionally uses coincident annihilation photons emitted from a positron interacting with an electron to localize cancer within the body. The formation of positronium (Ps), a bonded electron-positron pair, has not been utilized in clinical applications of PET due to the need to detect either the emission of a prompt gamma ray or the decay of higher-order coincident events. Assessment of the lifetime of the formed Ps, however, can potentially yield additional diagnostic information of the surrounding tissue because Ps properties vary due to void size and molecular composition.

Strength-duration curves for left bundle branch area pacing.

Background: Despite growing clinical use of left bundle branch pacing (LBBP), data regarding the fundamentals of this pacing modality, including chronaxie and rheobase, are scarce.

Objective: The purpose of this study was to calculate strength-duration curves with chronaxie and rheobase values for LBBP and left ventricular septal pacing (LVSP), and to analyze battery current drain and presence of selective LBBP at very short pulse duration (PD).

Methods: A group of 141 patients with permanent LBBP were studied.

Left bundle branch area pacing improves right ventricular function and synchrony.

Background: The impact of left bundle branch area pacing (LBBAP) on right ventricular (RV) function and tricuspid regurgitation (TR) remains unclear.

Objective: We aimed to assess the long-term effects of LBBAP on RV performance and on TR.

Methods: RV function was evaluated using RV free wall strain, tricuspid annular plane systolic excursion, fractional area changing, and systolic velocity of the lateral tricuspid annulus.

Accessory pathway localization with probabilistic density maps generated by a mobile application: Assessment of a full pre-excitation net-vector method.

Introduction: Precise electrocardiographic localization of accessory pathways (AP) can be challenging. Seminal AP localization studies were limited by complexity of algorithms and sample size. We aimed to create a nonalgorithmic method for AP localization based on color-coded maps of AP distribution generated by a web-based application.

Feasibility of the J-PET to monitor the range of therapeutic proton beams.

Purpose: The aim of this work is to investigate the feasibility of the Jagiellonian Positron Emission Tomography (J-PET) scanner for intra-treatment proton beam range monitoring.

Methods: The Monte Carlo simulation studies with GATE and PET image reconstruction with CASToR were performed in order to compare six J-PET scanner geometries. We simulated proton irradiation of a PMMA phantom with a Single Pencil Beam (SPB) and Spread-Out Bragg Peak (SOBP) of various ranges.

SPLIT: Statistical Positronium Lifetime Image Reconstruction via Time-Thresholding.

Positron emission tomography (PET) is a widely utilized medical imaging modality that uses positron-emitting radiotracers to visualize biochemical processes in a living body. The spatiotemporal distribution of a radiotracer is estimated by detecting the coincidence photon pairs generated through positron annihilations. In human tissue, about 40% of the positrons form positroniums prior to the annihilation.

Discrete symmetries tested at 10 precision using linear polarization of photons from positronium annihilations.

Discrete symmetries play an important role in particle physics with violation of CP connected to the matter-antimatter imbalance in the Universe. We report the most precise test of P, T and CP invariance in decays of ortho-positronium, performed with methodology involving polarization of photons from these decays. Positronium, the simplest bound state of an electron and positron, is of recent interest with discrepancies reported between measured hyperfine energy structure and theory at the level of 10 signaling a need for better understanding of the positronium system at this level.