2.1. Research Questions

2.2. Search Strategy and Study Selection Process

A systematic search was conducted to identify and select published studies using Metaverse as an emerging technology to diagnose diseases without time limitations. The searches were done in scientific databases, including PubMed, Web of Science, and IEEE Explore, by combining related keywords, according to Table 1. Published articles in English without time limitations were included in the study. We also searched Google Scholar to find other articles in the gray literature.

2.3. Inclusion and Exclusion Criteria

Articles related to the subject of the study, that is, the use of Metaverse, as an emerging technology, in the diagnosis of diseases, were included in the study. Considering that the study’s main aim was a comprehensive review, the articles that discussed various aspects, especially disease diagnosis, and provided sufficient information in this field were included. According to the systematic review protocol [40], the articles that used Metaverse to diagnose patients’ diseases in any healthcare-providing centers were selected. The selection process was done by two authors independently, and in case of contradictions, the authors discussed them to resolve the probable contradictions.

2.4. Data Extraction

Table 2 in the results section shows the most essential items in the data extraction form. Before data extraction, the first author checked each study and extracted the information from the article. Another author independently examined the articles and extracted the essential information. The authors checked for discrepancies in the extracted information, which were checked and resolved in small sessions.

2.5. Data Analyses

Data analyses were done using the content analysis method, and the results were summarized and reported in tables and figures based on the study objectives.

3.1. Features of the Included Articles

The searches were done in databases, and 1706 articles were found during the initial search. Finally, 28 articles were included in the study based on the steps performed in Figure 1.

Table 2 shows the main characteristics of the studies included in the study. It also contains the main information about the studies, such as their field of specialties, the type of data, the end users of Metaverse, and the main results.

All included articles were published between 2020 and 2024 based on the findings. Of the 28 articles entered, 10 were published in 2023 and 2022, the highest number compared to other years (Figure 2). However, only seven months of 2024 were reviewed, which could be higher in 2024.

Figure 3 shows the distribution of articles published by country. Most of the studies were conducted in China (seven articles), followed by India, South Korea, and the USA, each with four articles.

Figure 4 shows the distribution of article types in two main categories: original and nonoriginal. Based on the results, 47.14% of the studies were original on Metaverse in diagnosing diseases, and the rest were nonoriginal.

3.2. Types of Input Data in Metaverse to Diagnose Diseases

According to the results, the types of input data used to diagnose diseases using Metaverse can be categorized into five categories: video, image, audio, animation, and digital (Figure 5).

3.3. The Most Important Components and Technologies

Figure 6 shows the most important technologies and applications of Metaverse. Based on this figure, the 6 most important technologies related to Metaverse are placed in 8 main categories, and each of these technologies also has separate parts shown in the figure.

According to Figure 6, VR was the most used technology in developing Metaverse. It AR studies, and since Metaverse was used in disease diagnosis, artificial intelligence was also noted in the relevant studies. According to this figure, the two topics of the internet and COVID-19 have been introduced as effective factors in Metaverse implementation. Considering the important applications of the internet in establishing communication and COVID-19 as a factor in accelerating the development of the Metaverse in disease diagnosis, they are regarded as two background issues in this field [26, 57].

3.4. Main Effects of Using Metaverse in Diagnosing Diseases

In Table 3, the applications and effects of using Metaverse in the diagnosis of diseases are presented. Applications are displayed in five main categories and 23 subcategories.

3.5. Challenges and Limitations of Using Metaverse in Diagnosing Diseases

Table 4 shows the limitations and challenges of Metaverse in diagnosing diseases. Based on this table, limitations and challenges are listed in two main categories, including issues related to the Metaverse implementation and issues related to the Metaverse nature and legality in seven subcategories.

According to Table 4, the most important challenge in using the Metaverse in diagnosing diseases is related to its nature, and challenges related to the conducted studies have been emphasized more than others.

4.1. Features of the Studies

According to the study’s findings, as expected, most of the original studies have been conducted in technology-rich countries, including China, India, South Korea, and the USA. The issue of using Metaverse as a support tool in diagnosing diseases has not been given much attention in many countries. However, with the increasing trend of studies conducted from 2020 until now, it can be expected that the penetration rate of this technology in the health field will increase faster.

4.2. Types of Input Information in Metaverse to Diagnose Diseases

The study results showed that different data types are used in the Metaverse platform to diagnose diseases. The image and clinical data are the most important data types used to diagnose diseases. According to the results provided in Figure 5, the most common types of input images were MRI, CT scan, neuroimaging, and mammography images. Taking advantage of higher-quality images can increase the accuracy and precision of the diagnoses provided using Metaverse [60–62]. In addition to using different images to provide accurate diagnoses, digital data, audio and video data, and animation can be used.

4.3. Types of Medical Specialists’ Use of Metaverse

With the increasing use of Metaverse applications in health, more specialties use it to diagnose diseases. In the present study, 13 types of specialties used this technology to diagnose the disease. In addition to being used in diagnosing diseases, oncology, neurology and psychiatry, and ophthalmology are the most important fields that have used Metaverse to diagnose diseases. According to the results, it seems that the use of Metaverse in the diagnosis of breast cancer has been an effective method and is favored by experts [38, 41]. Metaverse can create a revolution in providing services to cancer patients. In such a way, it can be said that Metaverse may be the new paradigm and the next frontier in delivering cancer care services [63]. Using the Metaverse in the field of neurology can help in rehabilitating movements [64]. Also, due to the high sensitivity and importance of accurate diagnosis of eye diseases, much attention has been paid to using Metaverse in the field of ophthalmology, and many uses are being carried out [47]. However, with the expansion of this new field to provide services, the need for new guidelines is felt more and more [65, 66].

4.4. The Most Important Components and Technologies

Metaverse in health consists of various technologies, each of which is very complex and extensive, and it indicates that the project in this field will be very complex and expensive [26, 27, 67–70]. Since there is much infrastructural similarity between the two, the successful implementation of AR/VR will be an important step in implementing the Metaverse [26, 71]. Blockchain technology provides the capacity for extensive and unlimited exchange of information in a secure platform, and considering the importance of information exchange in the Metaverse, it will be one of the required technologies for the successful implementation of the Metaverse. The following section examines the most important technologies related to Metaverse. Important technologies related to Metaverse have been introduced in the following section.

VR became an important part of healthcare due to its high user-friendliness. VR is a technology that, using special systems, takes the user to a completely virtual and visual world [72–75]. This term plays an important role in the Metaverse because users can participate and interact with others as virtual characters in a digital world. For this reason, VR is very important in Metaverse projects.

The AR/VR method represents the basic model of Metaverse [76]. These technologies have created a digital world with imaginative visual content [77–79]. Due to the progress of VR, the Metaverse experience can be expanded to include physical simulation with VR equipment. In this case, users can feel, hear, and communicate with people in other parts of the world. Given the hype surrounding Metaverse, we expect Metaverse companies to invest more in developing AR and VR equipment soon.

One of the main components and concepts of Metaverse is artificial intelligence. The ever-increasing expansion of artificial intelligence capabilities and its transformation into a key technology in data analysis and diagnostic image processing facilitates decision-making in the Metaverse space [7, 80, 81]. The current study emphasizes the key role of artificial intelligence in the Metaverse and its importance in diagnosing diseases. Due to the widespread use of artificial intelligence in the diagnosis of diseases, in the reviewed studies, various capabilities of artificial intelligence, such as machine learning, image processing, and natural language processing, were used for accurate diagnosis of diseases.

Blockchain technology provides a decentralized and transparent solution for proof of digital ownership, digital receivables, value transfer, governance, accessibility, and interactivity [82–86]. Blockchain offers many possibilities, including transparency, security, and authentication in the Metaverse [82]. Blockchain and Metaverse combine to create new user experiences that were previously impossible [82]. This technology acts as an infrastructure to provide security and transparency in the Metaverse, while Metaverse creates a new world and can be used in the health field. The benefits above are increasing the use of blockchain in the health field. Using this technology in the Metaverse to diagnose diseases can largely resolve concerns about information security.

A digital twin is a virtual copy of anything in the “physical” world, be it a person, an organization, a system, or something else [87]. Digital Twins have the unique function of helping to improve reactions or provide appropriate responses to what is happening in real life. Hence, creating these twins bridges the gap between the physical and virtual worlds [88]. These virtual digital counterparts are made based on the data generated from the physical beings. Then, these twins allow the virtual beings to exist alongside their physical selves. Peers are useful for different purposes. In the current study, the digital twin is emphasized as one of the main parts of the Metaverse and can be one of the aspects of distinguishing the Metaverse from VR.

4.5. Outcomes of Applying Metaverse in Diagnosing Diseases

The results of the present study showed that the use of Metaverse is effective in diagnosis and care. This technology can increase the accuracy of diagnosing diseases [89]. Also, many reviewed studies have emphasized improving the quality-of-care services of Metaverse [51, 58, 59]. Another part of the studies showed that the timely use of Metaverse using artificial intelligence tools can lead to early prediction of diseases and prevent disease complications as much as possible [35]. Despite these capabilities, conducting more studies and experiments on Metaverse is necessary to provide health services and obtain more accurate results.

Another effect of the Metaverse in diagnosing diseases is improving interactions [25, 26, 57, 59]. By covering the weaknesses of VR and expanding its capabilities, Metaverse improves interactions between virtual and real space, and this issue is facilitated by capabilities such as digital twins and avatars [90]. Metaverse can engage patients more by facilitating interactions. Among the other applications of Metaverse mentioned in the studies, the training of patients and medical staff is mentioned. However, due to few studies in this field [46, 55, 58], problems related to security issues [38] and uncertainty about its definite effectiveness in predicting and diagnosing diseases [47] create a situation of uncertainty about this has been the subject.

4.6. Challenges of Metaverse for Diagnosing Diseases

Based on other results, challenges related to the conducted studies are an important issue in the Metaverse phenomenon. Some studies are unreliable [54, 55, 58], and the results of some implemented Metaverse projects may have yet to be published. Also, studies have yet to be conducted in this field due to the new emergence of this technology, and judging the effectiveness of Metaverse in diagnosing diseases requires more studies.

Among other issues facing Metaverse projects in diagnosing diseases, their high costs have been reported [25, 27, 35]. Considering the wide range of technologies available in these projects, Metaverse projects can expect high costs [91, 92]. It is suggested that sustainable financial resources be considered for implementing Metaverse projects.

Our study’s findings also emphasize technological and infrastructural challenges. In this context, items like human-computer interaction and inadequate technical standards can be mentioned [44, 47]. Implementing information technologies has faced these challenges [93–96], and researchers and developers have always tried to solve them. It seems that regarding the emerging nature of the Metaverse, especially in medical sciences, more studies and more Metaverse projects are suggested to facilitate this category of challenges.

The study results showed many legal challenges in implementing Metaverse projects and using Metaverse to provide diagnostic services entails special ethical and legal requirements [46, 51, 52]. Although some ethical and legal aspects can be used from other health information technologies, in some cases, Metaverse has its requirements, and experts must consider all factors and the ethical and legal requirements of Metaverse in compiling medical sciences [97–99]. All stakeholders should be seen in this issue, and their rights should be fully defined, which include doctors, paramedics, nurses, patients, health organizations and officials, and other people and institutions. It is necessary to see security standards and privacy and confidentiality of patients’ information in this new platform.

In Metaverse-based medicine, intellectual property, governance, and regulation challenges are particularly important [45, 100]. As diagnostic and therapeutic technologies proliferate in virtual environments, questions arise about the ownership of medical data, diagnostic algorithms, and content generated in the Metaverse [10]. On the other hand, governance in the Metaverse is complex due to its cross-border nature; national laws may not monitor medical activities in this space effectively. Also, the lack of comprehensive regulations to manage ethical and legal issues, such as patient privacy and physician liability in the virtual environment, requires urgent attention. These challenges highlight the need for national and international cooperation and the development of new legal frameworks to ensure the security, fairness, and effectiveness of the Metaverse in health.

In implementing new technologies such as Metaverse, a correct and accurate analysis of the existing situation and conducting a needs assessment in the relevant environment is one of the important and effective factors [26, 54]. For example, it should be checked to what extent the hospital or other appropriate healthcare centers need Metaverse technology, how ready to use it, and how receptive users will be to it in diagnosing diseases. After these checks, the project’s executive team should fix the problems and then take the next steps to implement it. For Metaverse projects in health, this study phase should be done with much more precision to ensure its success.

Concerning human issues, the use of the Metaverse in diagnosing diseases will bring challenges, such as the impact of the Metaverse on the behavior of patients and physicians, the transformation of doctor-patient relationships in the Metaverse, the social consequences of using the Metaverse in diagnosing diseases, and the psychological effects of Metaverse on patients [10, 101, 102]. While these issues have been addressed less, they must be addressed in future studies.