# Blockchain-Based Internet of Medical Things
## 1 Introduction  
Securely recovering and correctly managing the amount of individual health data created by delivering service operations and normal business is a major challenge for the healthcare industry. Most of the health data is not easy to access or standardized across systems, and is difficult to interchange, utilize, and understand. They are compiled from several locations and stored in centralized information technology systems, making them challenging to share and administer. Time and energy are required to synthesize, receive, send, and request medical information [1]. Safe data retrieval and management enable healthcare systems to improve health outcomes, communication, treatment quality, and patient views in their entirety [2]. Legacy systems are notorious for being incompatible with newer technologies and for only being able to communicate with other healthcare and medical systems on a limited scale. Data shows various advantages of integrating these networks for better and linked healthcare; however, researchers in health informatics should consider interconnection across different companies [3]. One of the biggest challenges in this area is multi-organizational data sharing, which requires healthcare providers to make their patients' medical records freely accessible to other organizations, including research or physician institutions [4]. Given the present state of affairs, comprehensive reform of the universal healthcare system is necessary. Historically, medical professionals have handled their evaluations, documentation, and reports on patients and any necessary adjustments to their treatments [5]. With longer life expectancies and a growing world population, a more powerful tool is required for population control. The Internet of Things (IoT) or other decentralized platforms may be employed in this context for achieving dispersed coverage [6]. In light of this, healthcare systems are a crucial IoT application [7, 8]. Internet of Medical Things (IoMT) is the kind of IoT that is used in the healthcare industry [9]. IoMTs are the wave of the future in healthcare since they will enable the connectivity and remote monitoring of all medical equipment [10]. Due to these developments, healthcare may now be provided more rapidly and at a lower cost [11]. Medical workers (nurses, physicians, etc. ), medical data servers, and medical sensor equipment make up the bulk of an IoMT system that provides remote healthcare [12; 13]. There is a long way to go before IoMT can be utilized widely. Most implanted and wearable medical sensor devices lack the computational power and battery life to make complex encryption schemes practical. This means that wireless data transport in the IoMT is open to external attacks [14]. Due to the sensitive nature of patient information included in medical records, it is important to realize that only authorized parties have access to these records [15]. Poor IoMT interoperability [16] is also a problem because of the wide range of medical sensor devices that are available [17] and the diversity of IoMT networks. The integration of blockchain with IoMT may address the above issues [16; 18]. Blockchain is defined by its specific openness, traceability, dependability, and decentralization features. Thus, blockchain technology may be able to address concerns with compatibility, confidentiality, and safety [19]. Blockchain makes it possible for parties who do not trust each other to nevertheless complete a variety of network transactions. Data from a distributed network of devices may be stored and tracked in a blockchain [20]. To the best of our knowledge, this systematic review offers a general overview of the present state, significance, and future of blockchain-based IoMTs, which has not been executed previously. The structure of the current investigation is as follows: The research methodology that was used to search, filter, and choose the literature is described in detail in Section 2.