I. Introduction
The metaverse, a rapidly growing concept, offers significant potential for the evolution of Internet and next-generation applications [1] in diverse fields such as gaming, social media, industry, and healthcare [2]. Characterized by immersive, hyper-spatiotemporal, and self-sustaining qualities, the metaverse envisions virtual avatars representing humans, objects, and other entities from the physical world, interacting in real-time within a simulated environment. This environment may emulate the physical world or be entirely synthesized. The recent Covid-19 pandemic has accelerated the development of virtual presence due to restrictions on physical interactions, bringing healthcare and its future advancements to the forefront of research. Consequently, the intersection of the metaverse and healthcare has emerged as a hot topic, with the integration of fundamental technologies such as Digital Twins (DTs), Virtual/Augmented/Mixed Reality (VR, AR, MR), 5G and beyond, IoT devices and sensors, Artificial Intelligence (AI), and distributed ledgers poised to revolutionize and personalize care for patients afflicted by various pathologies [3]. One such pathology is lung cancer, a leading cause of cancer-related mortality among men and women worldwide, accounting for approximately 18% of all cancer deaths in 2020 [4]. The prevalence and lethality of lung cancer have driven extensive research efforts to better understand the disease and develop effective treatments. In this context, the I3LUNG [5] project is at the forefront of developing an AI-based Decision Support System (DSS) to assist clinicians in treating patients with Non-Small-Cell Lung Cancer (NSCLC). Within this project, establishing a flexible environment that facilitates the exchange of ideas among physicians, analysis of data from previous clinical studies and the real world, and storage of patient information has emerged as a priority. In this paper, following the I3LUNG use case, we propose a fully distributed reference architecture for intelligent lung cancer patient care, namely MetaLung. By leveraging existing technologies, we discuss possible applications ranging from virtual consultations, to cancer diagnosis, disease monitoring, and remote treatment planning. Our contributions are threefold: