## 4 Analyses of the Applications of Digital Twin Models
### Medicine
#### 4.2.1 Application and Adoption of Digital Twin in Medicine
With governments and organizations supporting the digitization of healthcare, especially amidst the COVID-19 pandemic, continuous sensor monitoring aids in identifying symptoms and potential health issues, allowing for timely interventions and personalized treatments tailored to individual patient data, in alignment with the principles of personalized medicine. Following the report of the Digital Patient Roadmap [72], computational medicine includes technologies for modeling and simulation, targeting the creation of a digital element called a virtual patient used in prevention, diagnosis, and treatment planning. The virtual patient integrates knowledge from mathematics, computer science, bioengineering, and biomedicine. Because people differ, building a model requires collecting, integrating, and analyzing data from many patients to increase the accuracy of the model. Virtual patient acquisition technology should be completely autonomous. Philips [73] created a personalized \"HeartModel\" digital twin by combining Computed Tomography (CT) images before surgery with an X-ray information layer during the medical intervention for surgeon assistance and for providing 3D images in real time to suggest the correct choice and positioning of the devices used. In ref. [74], a model using a Digital Twin built based with the aid of intelligent algorithms for the diagnosis of chronic congestive heart failure, as well as tests for treatment, is presented. The electrical signals of the heart were simulated using electrolytes, and the models were based on Magnetic Resonance Imaging (MRI) and ECG measurements. Another representative example of personalized medicine was presented in [75]. Siemens Healthineers Turkey is in a continuous process of developing DTs for organs (especially the heart and brain) through 3D images. As a result of using this technology, the efficiency of operations increases. DTs are used to highlight pathologies from an early age, and the same company made a demonstration at TURKRAD 2019 that helps specialists identify and correct congenital heart defects in infants. From the desire to see the aging progresses at the cellular level and combat it, researchers have tried to find the correct treatment [76]. The focus has fallen on the development of the virtual patient, for which the digital twin corresponding to the physical patient uses the DNA genetic code for personalization and individualization. The virtual patients can also be used to provide guidance on exercise and diet choices that lead to an improved quality of life [77]. Until the development of DT technology, the vast majority of tests regarding the effects of certain drugs on certain organs were performed in animals [78]. The shift to simulation through DTs has opened the way for research in the field of personalized medicine [79], noting advantages such as observing the hearth complex structure in detail in the model of this organ and taking tissue mobility into account [80]. To capture information from patients, wireless equipment can be used to transmit real-time data, such as heart rate, blood pressure, and breathing [81]. Based on the data, predictions can monitor activity analysis to avoid depression or other neurological and psychiatric disorders. Devices have been developed that simulate the brain's electrical signals, with the patient having an electrode placed on each temple that transmits an electronic signal to the brain. The symptoms of depression can be reduced until they are eliminated. To collect real-time data from patients [82], applications have been developedwhere they can enter data, such as their mood and feelings, which can be stored in a database that the doctor can access at any moment. Based on the data, simulations can be carried out, and treatments are established with modifications of the treatment. Regarding the changes that may occur in the skeletal and muscular systems, through DTs using muscle activation and Electromyography (EMG) technologies, mobility deficiencies, paralysis, and imbalances in patients can be detected.