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Abstract Objective.This paper introduces a novel PET imaging methodology called 3-dimensional positron imaging (3Dπ), which integrates total-body coverage, time-of-flight (TOF) technology, ultra-low dose imaging capabilities, and ultra-fast readout electronics inspired by emerging technology from the DarkSide collaboration.Approach.The study evaluates the performance of 3Dπusing Monte Carlo simulations based on NEMA NU 2-2018 protocols. The methodology employs a homogenous, monolithic scintillator composed of liquid argon (LAr) doped with xenon (Xe) with silicon photomultipliers (SiPMs) operating at cryogenic temperatures.Main results.Substantial improvements in system performance are observed, with the 3Dπsystem achieving a noise equivalent count rate of 3.2 Mcps at 17.3 kBq ml⁻¹, continuing to increase up to 4.3 Mcps at 40 kBq ml⁻¹. Spatial resolution measurements show an average FWHM of 2.7 mm across both axial positions. The system exhibits superior sensitivity, with values reaching 373 kcps MBq⁻¹with a line source at the center of the field of view. Additionally, 3Dπachieves a TOF resolution of 151 ps at 5.3 kBq ml⁻¹, highlighting its potential to produce high-quality images with reduced noise levels.Significance.The study underscores the potential of 3Dπin improving PET imaging performance, offering the potential for shorter scan times and reduced radiation exposure for patients. The Xe-doped LAr offers advantages such as fast scintillation, enhanced light yield, and cost-effectiveness. Future research will focus on optimizing system geometry and further refining reconstruction algorithms to exploit the strengths of 3Dπfor clinical applications. 

Using a participatory observation approach, this paper aims at exploring how public and private organizations have collaborated in response to the COVID-19 pandemic. We examine the case of MechanicalVentilator Milano (MVM), an international project with over 250 contributors and partners; this project aimed to achieve the challenging goal of designing and realizing a mechanical ventilator for mass production in about 6 weeks. The project received the Emergency Use Authorization granted by the U.S. Food and Drug Administration. The MVM ventilator is a reliable, fail-safe, and easy-to-operate mechanical ventilator that can be produced quickly at a large-scale, based on the readily available parts. The success of the MVM case is unique as it adopts open innovation practices to generate technology innovation, in addition to a lean perspective. Through the MVM project description, this study offers a framework that explains the interplay between open innovation and lean approach, highlighting the different internal and external forces and types of collaborations, and offering fine-grained insights in to the role of universities as platforms of multidisciplinary knowledge. This framework might serve as a basis for future theoretical and empirical research, providing practitioners with new best practices that are essential when facing a severe crisis like COVID-19.