# VR/AR Technology in Human Anatomy Teaching and Operation Training

Authors: Yuan Zhou; Jiejun Hou; Qi Liu; Xu Chao; Nan Wang; Yu Chen; Jianjun Guan; Qi Zhang; Yongchang Diwu
Journal: Journal of Healthcare Engineering
 (2021)

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## Abstract

AR/VR technology can fuse the clinical imaging data and information to build an anatomical environment combining virtual and real, which is helpful to improve the interest of teaching and the learning initiative of medical students, and then improve the effect of clinical teaching. This paper studies the application and learning effect of the VR/AR system in human anatomy surgery teaching. This paper first shows the learning environment and platform of the VR/AR system, then explains the interface and operation of the system, and evaluates the teaching situation. This paper takes the VR/AR operation simulation system of an Irish company as an example and evaluates the learning effect of 41 students in our hospital. Research shows that the introduction of the feature reweighting module in the VR/AR surgery simulation system improves the accuracy of bone structure segmentation (IOU value increases from 79.62% to 83.56%). For real human ultrasound image data, the IOU value increases from 80.21% to 82.23% after the feature reweighting module is introduced. Therefore, the dense convolution module and feature reweighting module improve the learning ability of the network for bone structure features in ultrasound images from two aspects of feature connection and importance understanding and effectively improve the performance of bone structure segmentation.


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## Body

## 1. Introduction

At present, AR/VR technology has been applied in various fields, but its application in the medical field is still in the exploratory stage. With the rapid development of the digital era, the combination of AR/VR technology and medicine has unlimited prospects. It is believed that VR technology will bring disruptive changes in medical training, disease diagnosis, doctor-patient communication, clinical diagnosis, and treatment in the future. This paper reviews the application of AR/VR technology in medicine.VR technology has applied research in clinical medicine, for example, the use of VR technology to perform CT angiography (CTA) on patients and establish a patient's heart model to diagnose congenital heart disease (CHD). Another example is to select 36 children with heart disease and use AR/VR technology to diagnose the clinical manifestations of their arterial heart disease. The diagnosis of arterial heart disease is highly valued in the experience of AR/VR technology. AR/VR technology has significant advantages in anatomical identification and diagnosis [1]. Chabaa et al. applied AR/VR technology to the diagnosis of basilar invagination, which solves the possible interference in the diagnosis of basilar invagination by X-ray, CT, and MRI and makes it easier to evaluate and classify basilar invagination. In addition, it also points out that AR/VR technology has the same effect in the diagnosis of spinal deformity and complex fracture [2]. Yamashita et al. pointed out that, as the learning curve of the three-dimensional model is smoother than that of the two-dimensional image, AR/VR technology is of great significance for young surgeons to understand surgical theory and improve surgical operation skills [3]. Hochreiter and Schmidhuber believed that AR/VR technology cannot only protect doctors from radiation and other factors but also establish a disease model so that doctors can choose different surgical instruments and surgical methods to operate on the same patient for many times, so as to choose the best scheme [4]. Lv et al. used AR/VR technology to design a model of nasal endoscopic examination. Doctors who have used it said that the model well simulated the anatomical structure, and the feeling during the operation was basically consistent with that of living surgery [5].Jacob et al. have created a set of educational tools for lateral ventricular puncture using AR/VR technology. It is used for trainee lateral ventricular puncture training. The anatomical structure of orthopedics is complex, and it is difficult to convert a 2D image into a 3D model with only spatial imagination [6]. Shaikh et al. used AR/VR technology to build a 3D visual surgery education model, convert patient image data into holographic images, and import them into VR equipment, where teachers and students wear HoloLens at the same time [7]. Eladl et al. asked 16 surgeons to complete a series of actions such as standard nail transfer in the traditional CT-guided and VR-assisted laparoscopic trainer and found that the operation time, accuracy, and stability of the VR-assisted group were better than those of the CT-guided group, and the more complex the operation, the greater the difference of results [8]. Orlander et al. used AR/VR technology to complete percutaneous kyphoplasty. It was found that the number of intraoperative X-ray irradiation, operation time, and postoperative kyphosis angle in the VR group were less than or shorter than those in the traditional C-arm group [9]. Smeets et al. was the first to apply AR/VR technology in hepatectomy, realizing the accurate matching of the three-dimensional model hologram and target organ, and proposed that AR/VR technology can be applied in the field of hepatobiliary surgery [10]. The above studies mainly rely on CT and other technologies to examine the diseased parts and treat them after analysis. VR is also used in teaching. However, the learning of these technologies has gone through many processes, resulting in the reduction of the final learning effect.This paper studies the application and learning effect of the VR/AR system in the teaching of human anatomy surgery. This paper first demonstrates the learning environment and platform of the VR/AR system, then explains the interface and operation of the system, and evaluates the teaching situation. In order to break through the limitations of terminal types and enrich the interaction mode, this paper proposes a lightweight multiperson multiterminal cooperation mechanism, which ensures the collaborative effect and has the characteristics of simple application. In short, the system in this paper is highly practical, interesting, and interactive, which provides a new way for scientific display of big data on the Earth and a new means for exploring the mysteries of the Earth. The proposed multiperson multiterminal cooperation technology has strong practicability and scalability.


## 2. VR/AR Technology and Value in Teaching

### 2.1. Core Value of VR/AR Technology

The core value of VR/AR technology can be summarized from its system form, application direction, and main characteristics, which can be summarized as immersion, desktop, and enhanced and distributed system forms [11]. The immersive VR system is mainly for high-end applications, and its typical feature is the use of high-end graphics workstations (groups) and high-fidelity audio-visual touch devices, in order to obtain a better sense of immersion [12]. The desktop system is mainly for popular applications. Its typical feature is to build a simple system based on general hardware, personal computer, and conventional interactive devices. In order to make interaction more natural, Kinect, Wiimote, and other portable devices are generally used to obtain the user’s body posture and manipulation information; augmented reality is mainly for augmented reality applications. Its typical feature is that 3D registration is carried out on the basis of acquiring 3D pose, and virtual objects are superimposed on the real scene by using video transmission or optical transmission helmet-mounted display to increase the content of virtual reality fusion. The distributed model is mainly oriented to virtual reality network applications, building a shared and consistent virtual environment, carrying out collaborative interaction, and completing more complex functions [13]. At present, the distributed system based on 5g mobile Internet is the focus of research and application. The above four types of systems are not independent of each other. For example, immersive, desktop, and enhanced systems can be used as nodes of distributed systems and interconnected through the network; immersive or desktop systems can also learn from the concept of enhanced systems and add the function of virtual reality integration [14]. AR/VR technology directly displays the traditional two-dimensional image in front of the doctor, giving the doctor “perspective eye,” just like the patient standing in front of the doctor. At the same time, the doctor can place the “patient” in the required position for observation and avoid unnecessary trouble caused by interference from external factors reducing the possibility of misdiagnosis and missed diagnosis, and improving the success rate of diagnosis [15].


### 2.2. Medical Application of VR/AR Technology

Traditional imaging examinations mainly include X-ray, CT, magnetic resonance imaging (MRI), andB-ultrasound, and accurate diagnosis often requires years of clinical experience and high spatial imagination ability [16]. However, AR/VR technology can greatly reduce the demand for the above two capabilities [17]. At the same time, the application of AR/VR technology in clinical teaching of retroperitoneal tumor surgery, bone tumor, orthopedic surgery, and cardiovascular surgery has effectively improved the quality of teaching, stimulated students’ interest in learning, and improved students’ understanding of anatomical knowledge [18]. AR/VR technology fundamentally solves the differences in teaching performance caused by different cognition of the anatomical structure between teachers and students, different cognition of theoretical knowledge, and different spatial thinking ability between students [19]. At the same time, it makes up for the limitations of medical environment and medical ethics, as well as the reality of insufficient anatomical specimens so that students receive low-cost and high-income teaching and training, and shortens the doctor training cycle [20]. Based on the virtual medical model provided by VR, AR/VR technology combines virtual with reality so that medical students cannot only observe personally but also operate in their own place and truly apply what they have learned. However, how to combine AR/VR technology with clinical teaching is a problem that every discipline should consider [21].Physicians use AR/VR technology to gain a deeper understanding of surgical risks and surgical plans, reduce differences in patient-patient understanding, and reduce physician-patient inconsistencies caused by unequal medical knowledge and information [22]. As shown in Figure 1, VR technology can simulate the human body. Preoperative planning and simulation have become an important part of preoperative communication in many medical centers, and AR/VR technology will provide more effective communication methods in this regard [23]. Doctor-patient communication is a very important part of the clinical work, and good doctor-patient communication is the basis of the whole medical process. VR can shorten the distance between doctors and patients, transform abstract into concrete, improve the quality of communication, and reduce the contradiction between doctors and patients [24].Figure 1
VR/AR human body simulation screen display effect (part of the pictures come from the Irish company’s VR technology surgery simulation platform, no copyright requirements).


### 2.3. VR/AR Instruction Set Algorithm Based on Neural Network

One of the problems in current VR surgery simulation research is that researchers only consider the temporal characteristics of VR/AR surgery, but ignore the spatial correlation between regions. In addition, there will be short-term and long-term repetitive patterns in VR/AR surgery, which will lead to nonlinear periodic data and linear trend data in VR/AR surgery. Considering these factors in the process of VR/AR surgery prediction will help to improve the accuracy of prediction [25]. In order to solve the above problems, this paper decomposes the VR surgery simulation task into linear and nonlinear parts, uses the convolutional neural network (CNN) and long-term memory network (LSTM) as nonlinear components, and adds the historical data connection component to process the periodic term in VR/AR surgery time series, while the linear component uses the autoregressive model to realize the simulation. The two parts are integrated to complete the prediction of VR/AR surgery data. At the same time, CNN can find the spatial correlation of the data, while LSTM can extract the long-term dependence pattern of the data, which makes the prediction of VR/AR data more accurate. The proposed model consists of two parts: linear component and nonlinear component. The neural network model is used as a nonlinear component, while the autoregressive model is used as a linear component. The linear and nonlinear parts of VR/AR data are processed, respectively:(1)ΔWl3=−ηδl3Xl3=ηt−yf′Xl3Wl3Xl3,(2)δl3=t−yf′Xl3Wl3.The neural network model is composed of the convolutional neural network and long-term and short-term memory network. CNN is used to obtain the short-term local dependence pattern of variables, which solves the problem of ignoring the spatial correlation between regions in the current VR/AR surgery prediction model. It is used to capture the long-term development trend of data. The historical data connection component adds the past data into the prediction process to improve the accuracy of VR/AR surgery prediction:(3)δL=t−yf′XLWL,(4)δl=δl+1Wl+1Tf′XlWl.The autoregressive model is used to deal with the linear part of VR/AR surgery and enhance the robustness of the hybrid model to VR/AR surgery with the variable input scale. There is a certain periodicity in the real VR/AR operation data, so we can use the characteristics of VR/AR operation data to improve the prediction accuracy. For example, when you want to predict the VR/AR operation value at 5pm on that day, a classic method is to take the recent data records into account and also apply the VR/AR operation at 5pm in the past historical period to the prediction. Therefore, in the nonlinear part of the model, a historical data connection component is added innovatively, which connects the current hidden units with the hidden units in the same historical period in the adjacent time period and takes the VR/AR operation data in the historical period into account in the prediction process, which can make the VR/AR operation prediction more accurate:(5)E=12t−y2,(6)∂E∂Wl=−xlTδl,(7)ΔWl=−η∂E∂Wl=ηXlTδl.By combining the advantages of CNN and LSTM, the short-term and long-term dependence patterns of VR/AR surgery data were obtained, and the temporal characteristics and spatial correlation of VR/AR surgery were considered:(8)ΔWl2=−ηδl2Xl2=ηδl3Wl3Tf′Xl2Wl2Xl2,(9)δl2=δl3Wl3Tf′Xl2Wl2.The historical link component is added to introduce historical data into the prediction, and the autoregressive model is used to process the linear part of the data. Combined with the output of the linear and nonlinear parts, the final prediction result is obtained, which makes the hybrid model perform well in the VR/AR surgery prediction task. By designing a manual assembly task to install precision connectors, the precise installation relationship between the connector and socket is mainly expressed by the following ar instruction design:(10)ex−e−xex+e−x=x1+x.Logic constraint is an organic combination of user cognition and precision assembly at the information level. It transforms the assembly relationship between the pin of the connector and the pinhole of the socket into the distance constraint between two cross marks and obtains an output feature map. Its calculation process is shown in the following equation:(11)log2n+1≤depth≤log2n+2,(12)eσ,g=?e∏i=s1slHvivi⋅uμ,v.In the above equation,e is the excitation function, which represents the memory of LSTM and completes its own update by forgetting the old memory and adding new memory. The first step is to determine the information to be discarded in the cell state, which is mainly realized through the forgetting gate. It chooses whether to forget the cell state of the upper layer according to a certain probability. The calculation process can be represented by the following equation:(13)2m2d−2×m2≤n≤md−1×m,where m is the weight matrix and D is the value of the bias term of the forgetting gate. This step is completed in two steps: the first step is to use the function to determine which computer to update the 5-point value, and the second step is to create a new cell value through the function and add it to the state. The modification process can be expressed as follows:(14)σi=Hfi•ufix|σi∈G,i=1,2,⋯,n,(15)σ=∏i=s1slσivi=∏i=s1slHviviuvisi,μ=∑i=s1slvifi.It integrates the old memory through the forgetting gate and the new memory through the input gate. The update process is shown in the following equation:(16)σikjl=nΔikjl∑s=1nxikε−xjlε2Δikjlε,Δikjl>0;0,Δikjl<0.The final step is to determine the output, which will be based on the cell state. First, an original output value is obtained by a sigmoid function. Then, the unit state is calculated and scaled to a value between −1 and 1. Then, the output value of LSTM is obtained by multiplying the original output value pair by pair. The output results are (6) and (7):(17)Yij=ebij∑kebik∗X,(18)uj|i=wijAi∗tn.Commonly used in the processing of time series, its basic idea is to use the value of the same variablex at each time point before, to predict the value of the current time point. The autoregressive model is derived from linear regression in regression analysis, and it is modified. In linear regression, X is used to predict y, while in the autoregressive model, X is used to predict x, so it is called autoregressive. It has the characteristics of stationary, normal, and zero mean, and the value at t time can be expressed linearly by its previous n-step value. According to the idea of multiple linear regression, AR can be predicted. The model can be defined as follows:(19)Rssim=P−2μxμy+C12σxy+C2μx2+μy2+C1σx2+σy2+C2,(20)E1ij=cosS1i,S2j,where P and R are orders and coefficients, respectively, and E1ij represents the white noise sequence; then, the autoregressive model can be simply understood as a linear combination of one or more past values of x plus a random error. The use of the autoregressive model can solve this problem well. In order to prevent the gradient from disappearing and accelerate the convergence of the network, the maximum and minimum normalization is used to preprocess the data:(21)SAE=TP+TNTP+TN+FP+FN.The SAE model uses a logistic regression layer to complete the prediction task. Using the collected VR/AR data to complete the training and testing of LSTM, Gru, SAE models and the proposed CNN-LSTM + AR model and according to the prediction results to compare their model performance; among them, the test values of MSE, RMSE, and Mae are smaller; is as follows:(22)Yij=ebij∑kebik,(23)uj|i=wijAi,where k is the number of data, y is the actual value of the data, and u is the predicted value of the model.


## 2.1. Core Value of VR/AR Technology

The core value of VR/AR technology can be summarized from its system form, application direction, and main characteristics, which can be summarized as immersion, desktop, and enhanced and distributed system forms [11]. The immersive VR system is mainly for high-end applications, and its typical feature is the use of high-end graphics workstations (groups) and high-fidelity audio-visual touch devices, in order to obtain a better sense of immersion [12]. The desktop system is mainly for popular applications. Its typical feature is to build a simple system based on general hardware, personal computer, and conventional interactive devices. In order to make interaction more natural, Kinect, Wiimote, and other portable devices are generally used to obtain the user’s body posture and manipulation information; augmented reality is mainly for augmented reality applications. Its typical feature is that 3D registration is carried out on the basis of acquiring 3D pose, and virtual objects are superimposed on the real scene by using video transmission or optical transmission helmet-mounted display to increase the content of virtual reality fusion. The distributed model is mainly oriented to virtual reality network applications, building a shared and consistent virtual environment, carrying out collaborative interaction, and completing more complex functions [13]. At present, the distributed system based on 5g mobile Internet is the focus of research and application. The above four types of systems are not independent of each other. For example, immersive, desktop, and enhanced systems can be used as nodes of distributed systems and interconnected through the network; immersive or desktop systems can also learn from the concept of enhanced systems and add the function of virtual reality integration [14]. AR/VR technology directly displays the traditional two-dimensional image in front of the doctor, giving the doctor “perspective eye,” just like the patient standing in front of the doctor. At the same time, the doctor can place the “patient” in the required position for observation and avoid unnecessary trouble caused by interference from external factors reducing the possibility of misdiagnosis and missed diagnosis, and improving the success rate of diagnosis [15].


## 2.2. Medical Application of VR/AR Technology

Traditional imaging examinations mainly include X-ray, CT, magnetic resonance imaging (MRI), andB-ultrasound, and accurate diagnosis often requires years of clinical experience and high spatial imagination ability [16]. However, AR/VR technology can greatly reduce the demand for the above two capabilities [17]. At the same time, the application of AR/VR technology in clinical teaching of retroperitoneal tumor surgery, bone tumor, orthopedic surgery, and cardiovascular surgery has effectively improved the quality of teaching, stimulated students’ interest in learning, and improved students’ understanding of anatomical knowledge [18]. AR/VR technology fundamentally solves the differences in teaching performance caused by different cognition of the anatomical structure between teachers and students, different cognition of theoretical knowledge, and different spatial thinking ability between students [19]. At the same time, it makes up for the limitations of medical environment and medical ethics, as well as the reality of insufficient anatomical specimens so that students receive low-cost and high-income teaching and training, and shortens the doctor training cycle [20]. Based on the virtual medical model provided by VR, AR/VR technology combines virtual with reality so that medical students cannot only observe personally but also operate in their own place and truly apply what they have learned. However, how to combine AR/VR technology with clinical teaching is a problem that every discipline should consider [21].Physicians use AR/VR technology to gain a deeper understanding of surgical risks and surgical plans, reduce differences in patient-patient understanding, and reduce physician-patient inconsistencies caused by unequal medical knowledge and information [22]. As shown in Figure 1, VR technology can simulate the human body. Preoperative planning and simulation have become an important part of preoperative communication in many medical centers, and AR/VR technology will provide more effective communication methods in this regard [23]. Doctor-patient communication is a very important part of the clinical work, and good doctor-patient communication is the basis of the whole medical process. VR can shorten the distance between doctors and patients, transform abstract into concrete, improve the quality of communication, and reduce the contradiction between doctors and patients [24].Figure 1
VR/AR human body simulation screen display effect (part of the pictures come from the Irish company’s VR technology surgery simulation platform, no copyright requirements).


## 2.3. VR/AR Instruction Set Algorithm Based on Neural Network

One of the problems in current VR surgery simulation research is that researchers only consider the temporal characteristics of VR/AR surgery, but ignore the spatial correlation between regions. In addition, there will be short-term and long-term repetitive patterns in VR/AR surgery, which will lead to nonlinear periodic data and linear trend data in VR/AR surgery. Considering these factors in the process of VR/AR surgery prediction will help to improve the accuracy of prediction [25]. In order to solve the above problems, this paper decomposes the VR surgery simulation task into linear and nonlinear parts, uses the convolutional neural network (CNN) and long-term memory network (LSTM) as nonlinear components, and adds the historical data connection component to process the periodic term in VR/AR surgery time series, while the linear component uses the autoregressive model to realize the simulation. The two parts are integrated to complete the prediction of VR/AR surgery data. At the same time, CNN can find the spatial correlation of the data, while LSTM can extract the long-term dependence pattern of the data, which makes the prediction of VR/AR data more accurate. The proposed model consists of two parts: linear component and nonlinear component. The neural network model is used as a nonlinear component, while the autoregressive model is used as a linear component. The linear and nonlinear parts of VR/AR data are processed, respectively:(1)ΔWl3=−ηδl3Xl3=ηt−yf′Xl3Wl3Xl3,(2)δl3=t−yf′Xl3Wl3.The neural network model is composed of the convolutional neural network and long-term and short-term memory network. CNN is used to obtain the short-term local dependence pattern of variables, which solves the problem of ignoring the spatial correlation between regions in the current VR/AR surgery prediction model. It is used to capture the long-term development trend of data. The historical data connection component adds the past data into the prediction process to improve the accuracy of VR/AR surgery prediction:(3)δL=t−yf′XLWL,(4)δl=δl+1Wl+1Tf′XlWl.The autoregressive model is used to deal with the linear part of VR/AR surgery and enhance the robustness of the hybrid model to VR/AR surgery with the variable input scale. There is a certain periodicity in the real VR/AR operation data, so we can use the characteristics of VR/AR operation data to improve the prediction accuracy. For example, when you want to predict the VR/AR operation value at 5pm on that day, a classic method is to take the recent data records into account and also apply the VR/AR operation at 5pm in the past historical period to the prediction. Therefore, in the nonlinear part of the model, a historical data connection component is added innovatively, which connects the current hidden units with the hidden units in the same historical period in the adjacent time period and takes the VR/AR operation data in the historical period into account in the prediction process, which can make the VR/AR operation prediction more accurate:(5)E=12t−y2,(6)∂E∂Wl=−xlTδl,(7)ΔWl=−η∂E∂Wl=ηXlTδl.By combining the advantages of CNN and LSTM, the short-term and long-term dependence patterns of VR/AR surgery data were obtained, and the temporal characteristics and spatial correlation of VR/AR surgery were considered:(8)ΔWl2=−ηδl2Xl2=ηδl3Wl3Tf′Xl2Wl2Xl2,(9)δl2=δl3Wl3Tf′Xl2Wl2.The historical link component is added to introduce historical data into the prediction, and the autoregressive model is used to process the linear part of the data. Combined with the output of the linear and nonlinear parts, the final prediction result is obtained, which makes the hybrid model perform well in the VR/AR surgery prediction task. By designing a manual assembly task to install precision connectors, the precise installation relationship between the connector and socket is mainly expressed by the following ar instruction design:(10)ex−e−xex+e−x=x1+x.Logic constraint is an organic combination of user cognition and precision assembly at the information level. It transforms the assembly relationship between the pin of the connector and the pinhole of the socket into the distance constraint between two cross marks and obtains an output feature map. Its calculation process is shown in the following equation:(11)log2n+1≤depth≤log2n+2,(12)eσ,g=?e∏i=s1slHvivi⋅uμ,v.In the above equation,e is the excitation function, which represents the memory of LSTM and completes its own update by forgetting the old memory and adding new memory. The first step is to determine the information to be discarded in the cell state, which is mainly realized through the forgetting gate. It chooses whether to forget the cell state of the upper layer according to a certain probability. The calculation process can be represented by the following equation:(13)2m2d−2×m2≤n≤md−1×m,where m is the weight matrix and D is the value of the bias term of the forgetting gate. This step is completed in two steps: the first step is to use the function to determine which computer to update the 5-point value, and the second step is to create a new cell value through the function and add it to the state. The modification process can be expressed as follows:(14)σi=Hfi•ufix|σi∈G,i=1,2,⋯,n,(15)σ=∏i=s1slσivi=∏i=s1slHviviuvisi,μ=∑i=s1slvifi.It integrates the old memory through the forgetting gate and the new memory through the input gate. The update process is shown in the following equation:(16)σikjl=nΔikjl∑s=1nxikε−xjlε2Δikjlε,Δikjl>0;0,Δikjl<0.The final step is to determine the output, which will be based on the cell state. First, an original output value is obtained by a sigmoid function. Then, the unit state is calculated and scaled to a value between −1 and 1. Then, the output value of LSTM is obtained by multiplying the original output value pair by pair. The output results are (6) and (7):(17)Yij=ebij∑kebik∗X,(18)uj|i=wijAi∗tn.Commonly used in the processing of time series, its basic idea is to use the value of the same variablex at each time point before, to predict the value of the current time point. The autoregressive model is derived from linear regression in regression analysis, and it is modified. In linear regression, X is used to predict y, while in the autoregressive model, X is used to predict x, so it is called autoregressive. It has the characteristics of stationary, normal, and zero mean, and the value at t time can be expressed linearly by its previous n-step value. According to the idea of multiple linear regression, AR can be predicted. The model can be defined as follows:(19)Rssim=P−2μxμy+C12σxy+C2μx2+μy2+C1σx2+σy2+C2,(20)E1ij=cosS1i,S2j,where P and R are orders and coefficients, respectively, and E1ij represents the white noise sequence; then, the autoregressive model can be simply understood as a linear combination of one or more past values of x plus a random error. The use of the autoregressive model can solve this problem well. In order to prevent the gradient from disappearing and accelerate the convergence of the network, the maximum and minimum normalization is used to preprocess the data:(21)SAE=TP+TNTP+TN+FP+FN.The SAE model uses a logistic regression layer to complete the prediction task. Using the collected VR/AR data to complete the training and testing of LSTM, Gru, SAE models and the proposed CNN-LSTM + AR model and according to the prediction results to compare their model performance; among them, the test values of MSE, RMSE, and Mae are smaller; is as follows:(22)Yij=ebij∑kebik,(23)uj|i=wijAi,where k is the number of data, y is the actual value of the data, and u is the predicted value of the model.


## 3. VR/AR Surgery Teaching

### 3.1. Content

This paper studies the application and learning effect of the VR/AR system in human anatomy surgery teaching. This paper first shows the learning environment and platform of the VR/AR system, then explains the interface and operation of the system, and evaluates the teaching situation. This paper takes the VR/AR operation simulation system of an Irish company as an example and evaluates the learning effect of 41 students in our hospital.


### 3.2. Design and Teaching Effect Evaluation

The traditional preoperative planning and discussion mainly rely on two-dimensional imaging information, such as X-ray, CT, and MRI, and then present the three-dimensional effect in the brain, which depends on the operator’s mastery of anatomical knowledge and spatial imagination ability. Due to the differences in these two aspects, it is very likely that different surgeons will have different understanding of the patient’s condition, resulting in different surgical options. In addition, due to the anatomical variation, the information is not accurate, which will also affect the formulation of precise treatment plan, leading to the increase of surgical risk. In this paper, AR/VR technology is used to implement accurate puncture and accurate positioning of the lesion area for patients, so as to achieve accurate personalized treatment of human disease location. Based on sufficient preoperative preparation and planning, the conventional preoperative discussion is to make the choice of operation mode and the development of operation process accurate, smooth, and practical. The application of AR/VR technology in preoperative preparation and planning not only adds a very professional “imaging” expert but also visually shows the operator’s simulation of the operation process before operation, which further increases the accuracy and rationality of the operation.41 questionnaires were sent to the education reform group, and the recovery rate was 100%. The questionnaire survey shows that 98.9% of the students are interested in the two-way feedback method (VR/AR surgery teaching of human anatomy), 95.6% of the students think that the teaching time of VR/AR surgery teaching of human anatomy is appropriate, 93.4% of the students think that VR/AR surgery teaching of human anatomy is appropriate, 91.3% of the students think that teachers can provide them with specific suggestions on how to improve their academic performance, 92.3% of the students think that VR/AR surgery teaching of human anatomy can improve their self-evaluation ability, 94.5% of the students think that VR/AR surgery teaching of human anatomy can improve their autonomous learning ability, 93.4% of the students think that VR/AR surgery teaching of human anatomy can improve their self-evaluation ability and VR/AR teaching of human anatomy can stimulate students’ learning interest and self-confidence. 86.9% of the students are willing to discuss teaching methods with teachers in an open way, and 90.2% of the students think that VR/AR teaching of human anatomy is conducive to understanding and mastering anatomical knowledge. The students’ opinions in the group discussion also support the above results.


## 3.1. Content

This paper studies the application and learning effect of the VR/AR system in human anatomy surgery teaching. This paper first shows the learning environment and platform of the VR/AR system, then explains the interface and operation of the system, and evaluates the teaching situation. This paper takes the VR/AR operation simulation system of an Irish company as an example and evaluates the learning effect of 41 students in our hospital.


## 3.2. Design and Teaching Effect Evaluation

The traditional preoperative planning and discussion mainly rely on two-dimensional imaging information, such as X-ray, CT, and MRI, and then present the three-dimensional effect in the brain, which depends on the operator’s mastery of anatomical knowledge and spatial imagination ability. Due to the differences in these two aspects, it is very likely that different surgeons will have different understanding of the patient’s condition, resulting in different surgical options. In addition, due to the anatomical variation, the information is not accurate, which will also affect the formulation of precise treatment plan, leading to the increase of surgical risk. In this paper, AR/VR technology is used to implement accurate puncture and accurate positioning of the lesion area for patients, so as to achieve accurate personalized treatment of human disease location. Based on sufficient preoperative preparation and planning, the conventional preoperative discussion is to make the choice of operation mode and the development of operation process accurate, smooth, and practical. The application of AR/VR technology in preoperative preparation and planning not only adds a very professional “imaging” expert but also visually shows the operator’s simulation of the operation process before operation, which further increases the accuracy and rationality of the operation.41 questionnaires were sent to the education reform group, and the recovery rate was 100%. The questionnaire survey shows that 98.9% of the students are interested in the two-way feedback method (VR/AR surgery teaching of human anatomy), 95.6% of the students think that the teaching time of VR/AR surgery teaching of human anatomy is appropriate, 93.4% of the students think that VR/AR surgery teaching of human anatomy is appropriate, 91.3% of the students think that teachers can provide them with specific suggestions on how to improve their academic performance, 92.3% of the students think that VR/AR surgery teaching of human anatomy can improve their self-evaluation ability, 94.5% of the students think that VR/AR surgery teaching of human anatomy can improve their autonomous learning ability, 93.4% of the students think that VR/AR surgery teaching of human anatomy can improve their self-evaluation ability and VR/AR teaching of human anatomy can stimulate students’ learning interest and self-confidence. 86.9% of the students are willing to discuss teaching methods with teachers in an open way, and 90.2% of the students think that VR/AR teaching of human anatomy is conducive to understanding and mastering anatomical knowledge. The students’ opinions in the group discussion also support the above results.


## 4. VR/AR System Platform Display and Teaching Training Effect

### 4.1. VR/AR Equipment and System Effect

As shown in Figure2, the VR device can put the three-dimensional model into the surgical field of vision, and the operator’s line of sight needs to leave the surgical area for observation, which may lead to the risk that the emergency treatment in the surgical area is not timely. During the operation, AR/VR technology projects the model on the patient’s body surface, which can clearly display the anatomical structure, reduce the difficulty of identifying the anatomical variant structure, and do not need to expand the incision. It can accurately know the location of the important anatomical structure around the operation field and avoid accidental injury. In addition, for tumor patients, it can design the tumor margin in advance, so as to avoid the insufficient resection range affecting the prognosis. VR has a good application prospect in surgery. With the application of intraoperative VR, more and more ways will be found to improve the quality of surgery.Figure 2
System equipment and operations (some pictures are from the Internet, searched through Google, no copyright requirements).As shown in Figure3, VR breaks through the limitation of space, enabling doctors and patients to communicate directly between the two places, providing convenience for both sides, saving a lot of time and energy, and optimizing the use of medical resources. Due to the limited level of medical care in some cities in our country, it is difficult to get good treatment for some rare diseases. This requires experts from other cities to conduct remote consultation. The traditional consultation model is time-consuming and laborious. It can be seen from the learning mode in the figure that the simulation effect of this technology is very realistic, so the AR/VR technology solves the problem of low efficiency in the traditional mode.Figure 3
Learning scene and VR effect (some pictures are from the Internet, searched through Google, no copyright requirements).


### 4.2. AR/VR Technology in Human Anatomy Teaching

As shown in Figure4, through AR/VR technology, students can be arranged to learn in situations that are difficult to achieve or rarely appear in reality. VR-assisted rapid rehabilitation teaching of human anatomy after minimally invasive surgery of femoral neck fracture has achieved good results. VR was used to generate the three-dimensional model in real time during the operation, and the quality of preoperative visit was improved by immersive experience. VR simulation of surgical instruments, operating beds, operating lights, etc., established a simulation operating room, which can be applied to the training of operating room doctors.Figure 4
VR/AR system operation screen view effect (some pictures are from the Internet, searched through Google, no copyright requirements).As shown in Figure5, VR was used to assist the preoperative localization of small pulmonary nodules, and the localization was accurate. Left upper lobectomy was successfully performed in 1 case. Two patients with chest wall tumor were scanned by thin-layer CT with AR/VR technology. DICOM data were obtained and input into the computer to generate the three-dimensional model. AR/VR technology has been applied in many clinical disciplines, and cardiothoracic surgeons have begun to explore the related application of AR/VR technology in this specialty.Figure 5
Human anatomy operation platform system display (some pictures are from the Internet, searched through Google, no copyright requirements).As shown in Table1, three-dimensional simulation of the heart specimens of patients with congenital heart disease by AR/VR technology not only found that the three-dimensional model showed the damage parts of complex congenital heart disease in more detail but also found that the high-fidelity three-dimensional model can be used for specimen preservation and teaching. At the same time, VR is used to design the intraoperative margin to guide the operation, which can reduce the operation cost, shorten the operation time, and reduce the preoperative CT positioning and other additional procedures. However, the application of AR/VR technology in cardiothoracic surgery is still backward compared with other specialties, and its application in clinical practice is only limited to a few cases reported. Therefore, a lot of clinical work is still needed to explore the application prospect of AR/VR technology in cardiothoracic surgery.Table 1
The effect of AR/VR three-dimensional simulation.
Surgical costPreoperativeSurgical routeModelHuman bodyShow virtualAR/VROperation time3.51.252.141.353.191.98Preoperative2.654.143.425.655.752.11CT positioning5.762.211.35.614.794.99CT scan3.623.541.734.372.182.73Weight3.164.221.66.921.441.58Planning6.726.881.336.433.435.55Needle path4.975.586.821.455.264.82As shown in Figure6, scientific knowledge can be simplified and displayed interestingly through AR technology, which can improve learning interest, enhance understanding, and improve learning effect. However, the application of AR technology in the field of science popularization is not mature enough, and the way is relatively simple. The most common way is to take pictures as recognition targets and superimpose animation models on them, such as stereo books and intelligent maps. Most of the popular science display methods of Earth big data are physical globe, video, animation model, etc., with less interaction, and the depth and breadth of information display are limited. In the context of human beings entering the ubiquitous network era, intelligent terminals can be interconnected in various ways to realize the cooperation between multiple terminals, dynamically adapt to user needs and network environment changes, and maximize resources.Figure 6
Human anatomical bone processing and simulation screen (some pictures are from the Internet, searched through Google, no copyright requirements).As shown in Table2, multiterminal collaboration technology can combine the advantages of different terminals to provide users with more high-quality and convenient services. Most of the existing multiterminal cooperation schemes focus on the definition, characteristics, and application scenarios’ expansion, with few specific implementation methods and large scale, which is not suitable for simple application development. To solve these problems, this paper proposes and implements a multiperson interactive Globe System based on AR. The system combines AR technology with visualization technology. According to the characteristics of different kinds of Earth data, a new 3D visualization display scheme is designed to display the Earth big data in three-dimensional space, enrich the user experience, and improve the interest.Table 2
Advantages of different terminals.
Virtual realityVisualizationAugmented realityCommunicationVisualization algorithmEnhanced interaction1.770.210.320.53Multiplayer and multiterminal3.51.241.092.62Collaborative service4.482.455.373.393D1.865.83.393.25As shown in Figure7, based on the u-net model, two improvements of the dense convolution module and feature reweighting module are added to the bone structure segmentation model. These two points are important to improve the performance of bone segmentation.Figure 7
Dense convolution module and feature reweighting module.The comparison of bone structure segmentation performance under different experimental settings is shown in Table3. It can be seen that the dense convolution module can enhance the transmission of ultrasonic image features and effectively improve the bone structure segmentation performance. For the phantom ultrasound image, the IOU (intersection over union) value increases from 81.21% to 82.97% after the dense convolution module is added. Similarly, for real human ultrasound image data, the introduction of the dense convolution module also improves the accuracy of bone structure segmentation (IOU value increases from 79.78% to 81.34%).Table 3
Comparison of bone structure segmentation performance.
DenseUltrasound imageFeatureBone structureSegmentationPhantomIOU valueSegmentation0.241.721.871.260.340.84Accuracy1.813.011.662.012.773.05Convolution4.663.213.543.014.062.32Transfer2.472.612.483.611.052.21As shown in Figure8, the introduction of the feature reweighting module increases the network’s understanding of the importance of channel features, which can further improve the performance of bone structure segmentation. For the phantom ultrasound image, the introduction of the feature reweighting module improved the accuracy of bone structure segmentation (IOU value increased from 60.62% to 83.56%). For real human ultrasound image data, the IOU value increases from 68.21% to 82.23% after the feature reweighting module is introduced. Therefore, the dense convolution module and feature reweighting module improve the learning ability of the network for bone structure features in ultrasound images from two aspects of feature connection and importance understanding and effectively improve the performance of bone structure segmentation.Figure 8
Feature reweighting module network channel characteristics.As shown in Figure9, in order to quantitatively evaluate the accuracy of bone structure reconstruction based on ultrasonic image segmentation, agar phantom was further scanned by CT after ultrasonic acquisition to obtain the real three-dimensional structure of the femoral head.Figure 9
Segmentation of the bone structure in ultrasound images.As shown in Table4, the three-dimensional bone structure reconstructed from the ultrasound image is accurate. After obtaining the reconstructed three-dimensional model, the reconstructed bone structure is displayed by using stereo holography technology. In addition, VR/AR system further shows the augmented reality visualization results of the fusion of the real three-dimensional femoral head structure and the three-dimensional model reconstructed from the ultrasonic image. We need to reconstruct the segmented bone structure image directly, and the reconstruction speed is about 18 frames/second. In addition, the rendering speed of GPU and OpenGL is about 30 frames.Table 4
Three-dimensional bone structure reconstructed in ultrasound images.
DenseIOUSegmentationAccuracyConvolutionTransferUltrasound image1.370.461.30.551.21Feature1.293.51.252.141.3Bone structure5.272.654.143.424.03Segmentation2.855.762.211.32.37Phantom ultrasound1.073.623.541.732.58IOU value1.433.164.221.64.72


### 4.3. VR/AR Technology in Operation Teaching and Training

As shown in Figure10, digital technology can transmit this model to any place; VR can present the intuitive three-dimensional model and realize convenient and fast remote expert consultation. The application of AR/VR technology in the field of medicine has been initially formed, but there are still some shortcomings. The biggest problem of AR/VR technology is that the matching accuracy between the virtual model and real world still needs to be further improved, which may be one of the reasons why cardiothoracic surgery is relatively backward in AR/VR technology application compared with other majors.Figure 10
Transmission and application scope of VR technology.Different vision of VR device wearers will also cause the difference between the model and the real world. As shown in Figure11, intraoperative operation can cause tissue deformation, displacement, etc. In addition, the establishment of the VR three-dimensional model depends on imaging and computer science professionals, and it takes a long time. The ergonomics of VR equipment still needs to be improved, such as equipment power, wearing comfort, and other aspects. Long time wearing VR equipment may cause nausea and dizziness and increase the risk of surgery to a certain extent. At present, there is no special software for medical needs in VR devices, but commercial software is used in medical practice, and its potential risks are unknown.Figure 11
The difference between the model and the real world.


### 4.4. Discussion

AR/VR technology is a new type of holographic imaging technology after AR, VR, 3D printing, and other modern technologies. It combines the advantages of AR and VR technology. In addition, VR model is more realistic. It can be removed and replaced by coloring, transparency, or at will to get the desired model, which is more practical than the traditional printing model. Through the use of virtual simulation technology to build clinical scenarios and the unique comparative teaching method of clinical differential diagnosis experts, each case is divided into history collection, physical examination, auxiliary examination, examination results, differential diagnosis, treatment plan, and other functional modules, and through a large amount of clinical data collection, the data of diagnosis and treatment process are exchanged by text, sound, image, and other multimedia. The virtual clinical operation technology is integrated into the case, and the clinical skills and clinical thinking ability of medical students are comprehensively improved by using the online assessment and evaluation function of the system. AR/VR technology can meet the training of this skill and has repeatability. In the process of real-time teaching, the difficulty of real-time data processing can be solved. Some scholars have established a virtual three-dimensional reduction model of distal radius extension fracture, which further strengthens the promotion of bone setting manipulation and the mechanism research of manipulation effect. In the process of manipulation operation, we can clearly see that bone setting manipulation effect improves the displacement of the fracture end. Orthopedic surgery requires high aseptic conditions, so medical students will be limited in the operation observation. Although endoscopic technology is widely used, but the camera picture lacks a sense of orientation and space and can only see the anatomical structure in the picture, but can not observe the operator’s operation method of surgical instruments, resulting in medical students to lose interest in learning surgery, and orthopedic surgery gradually tends to be minimally invasive; it is difficult for medical students to further learn surgical operation skills. With the help of virtual technology, the above problems can be effectively solved by online live broadcast of surgery. AR/VR technology is a new type of holographic imaging technology that has emerged after modern technologies such as AR, VR, and 3D printing. It combines the advantages of AR and VR technology. In addition, the VR model is more realistic and can be obtained by coloring, transparent or arbitrary removal, and replacement. The desired model is more practical than the traditional printing model. Through the use of virtual simulation technology to construct clinical scenarios and the unique comparative teaching method of clinical differential diagnosis experts, each case is divided into multiple functional modules such as medical history collection, physical examination, auxiliary examination, examination results, differential diagnosis, and treatment plan. Through a large amount of clinical data collection, the information of the diagnosis and treatment process is displayed to learners in the form of text, sound, image, and other multimedia interaction, and virtual clinical operation technology is integrated into the case, and further, through the online assessment and evaluation comparison in the application system function, the clinical skills and clinical thinking ability of medical students are comprehensively improved. AR/VR technology can meet the training of this skill, and it is repetitive. A new solid fracture model can be developed by analyzing the solid fracture model combined with data processing technology. During the manual reduction process, the synchronization of the manual effect information is completed in real time, which solves the practical difficulties of manual reduction teaching. Some scholars have established a virtual three-dimensional reduction model of the distal radius extension fracture, which has further strengthened the promotion of the orthopedic technique and the study of the mechanism of the maneuver effect. During the manipulation, the effect of the orthopedic technique can be clearly seen to improve the fracture end and the displacement situation. Orthopedic surgery requires high aseptic conditions, and medical students will be restricted when performing surgical observations. Although laparoscopic technology is widely used, the camera images lack a sense of orientation and space and can only see the anatomical structure in the image, but cannot observe the operation method of the surgeon’s surgical instruments, causing medical students to lose interest in learning surgery; moreover, orthopedic surgery is gradually becoming more minimally invasive, and it is difficult for medical students to further learn surgical techniques. With the help of virtual technology, the abovementioned problems can be effectively solved through online live broadcast of surgery.


## 4.1. VR/AR Equipment and System Effect

As shown in Figure2, the VR device can put the three-dimensional model into the surgical field of vision, and the operator’s line of sight needs to leave the surgical area for observation, which may lead to the risk that the emergency treatment in the surgical area is not timely. During the operation, AR/VR technology projects the model on the patient’s body surface, which can clearly display the anatomical structure, reduce the difficulty of identifying the anatomical variant structure, and do not need to expand the incision. It can accurately know the location of the important anatomical structure around the operation field and avoid accidental injury. In addition, for tumor patients, it can design the tumor margin in advance, so as to avoid the insufficient resection range affecting the prognosis. VR has a good application prospect in surgery. With the application of intraoperative VR, more and more ways will be found to improve the quality of surgery.Figure 2
System equipment and operations (some pictures are from the Internet, searched through Google, no copyright requirements).As shown in Figure3, VR breaks through the limitation of space, enabling doctors and patients to communicate directly between the two places, providing convenience for both sides, saving a lot of time and energy, and optimizing the use of medical resources. Due to the limited level of medical care in some cities in our country, it is difficult to get good treatment for some rare diseases. This requires experts from other cities to conduct remote consultation. The traditional consultation model is time-consuming and laborious. It can be seen from the learning mode in the figure that the simulation effect of this technology is very realistic, so the AR/VR technology solves the problem of low efficiency in the traditional mode.Figure 3
Learning scene and VR effect (some pictures are from the Internet, searched through Google, no copyright requirements).


## 4.2. AR/VR Technology in Human Anatomy Teaching

As shown in Figure4, through AR/VR technology, students can be arranged to learn in situations that are difficult to achieve or rarely appear in reality. VR-assisted rapid rehabilitation teaching of human anatomy after minimally invasive surgery of femoral neck fracture has achieved good results. VR was used to generate the three-dimensional model in real time during the operation, and the quality of preoperative visit was improved by immersive experience. VR simulation of surgical instruments, operating beds, operating lights, etc., established a simulation operating room, which can be applied to the training of operating room doctors.Figure 4
VR/AR system operation screen view effect (some pictures are from the Internet, searched through Google, no copyright requirements).As shown in Figure5, VR was used to assist the preoperative localization of small pulmonary nodules, and the localization was accurate. Left upper lobectomy was successfully performed in 1 case. Two patients with chest wall tumor were scanned by thin-layer CT with AR/VR technology. DICOM data were obtained and input into the computer to generate the three-dimensional model. AR/VR technology has been applied in many clinical disciplines, and cardiothoracic surgeons have begun to explore the related application of AR/VR technology in this specialty.Figure 5
Human anatomy operation platform system display (some pictures are from the Internet, searched through Google, no copyright requirements).As shown in Table1, three-dimensional simulation of the heart specimens of patients with congenital heart disease by AR/VR technology not only found that the three-dimensional model showed the damage parts of complex congenital heart disease in more detail but also found that the high-fidelity three-dimensional model can be used for specimen preservation and teaching. At the same time, VR is used to design the intraoperative margin to guide the operation, which can reduce the operation cost, shorten the operation time, and reduce the preoperative CT positioning and other additional procedures. However, the application of AR/VR technology in cardiothoracic surgery is still backward compared with other specialties, and its application in clinical practice is only limited to a few cases reported. Therefore, a lot of clinical work is still needed to explore the application prospect of AR/VR technology in cardiothoracic surgery.Table 1
The effect of AR/VR three-dimensional simulation.
Surgical costPreoperativeSurgical routeModelHuman bodyShow virtualAR/VROperation time3.51.252.141.353.191.98Preoperative2.654.143.425.655.752.11CT positioning5.762.211.35.614.794.99CT scan3.623.541.734.372.182.73Weight3.164.221.66.921.441.58Planning6.726.881.336.433.435.55Needle path4.975.586.821.455.264.82As shown in Figure6, scientific knowledge can be simplified and displayed interestingly through AR technology, which can improve learning interest, enhance understanding, and improve learning effect. However, the application of AR technology in the field of science popularization is not mature enough, and the way is relatively simple. The most common way is to take pictures as recognition targets and superimpose animation models on them, such as stereo books and intelligent maps. Most of the popular science display methods of Earth big data are physical globe, video, animation model, etc., with less interaction, and the depth and breadth of information display are limited. In the context of human beings entering the ubiquitous network era, intelligent terminals can be interconnected in various ways to realize the cooperation between multiple terminals, dynamically adapt to user needs and network environment changes, and maximize resources.Figure 6
Human anatomical bone processing and simulation screen (some pictures are from the Internet, searched through Google, no copyright requirements).As shown in Table2, multiterminal collaboration technology can combine the advantages of different terminals to provide users with more high-quality and convenient services. Most of the existing multiterminal cooperation schemes focus on the definition, characteristics, and application scenarios’ expansion, with few specific implementation methods and large scale, which is not suitable for simple application development. To solve these problems, this paper proposes and implements a multiperson interactive Globe System based on AR. The system combines AR technology with visualization technology. According to the characteristics of different kinds of Earth data, a new 3D visualization display scheme is designed to display the Earth big data in three-dimensional space, enrich the user experience, and improve the interest.Table 2
Advantages of different terminals.
Virtual realityVisualizationAugmented realityCommunicationVisualization algorithmEnhanced interaction1.770.210.320.53Multiplayer and multiterminal3.51.241.092.62Collaborative service4.482.455.373.393D1.865.83.393.25As shown in Figure7, based on the u-net model, two improvements of the dense convolution module and feature reweighting module are added to the bone structure segmentation model. These two points are important to improve the performance of bone segmentation.Figure 7
Dense convolution module and feature reweighting module.The comparison of bone structure segmentation performance under different experimental settings is shown in Table3. It can be seen that the dense convolution module can enhance the transmission of ultrasonic image features and effectively improve the bone structure segmentation performance. For the phantom ultrasound image, the IOU (intersection over union) value increases from 81.21% to 82.97% after the dense convolution module is added. Similarly, for real human ultrasound image data, the introduction of the dense convolution module also improves the accuracy of bone structure segmentation (IOU value increases from 79.78% to 81.34%).Table 3
Comparison of bone structure segmentation performance.
DenseUltrasound imageFeatureBone structureSegmentationPhantomIOU valueSegmentation0.241.721.871.260.340.84Accuracy1.813.011.662.012.773.05Convolution4.663.213.543.014.062.32Transfer2.472.612.483.611.052.21As shown in Figure8, the introduction of the feature reweighting module increases the network’s understanding of the importance of channel features, which can further improve the performance of bone structure segmentation. For the phantom ultrasound image, the introduction of the feature reweighting module improved the accuracy of bone structure segmentation (IOU value increased from 60.62% to 83.56%). For real human ultrasound image data, the IOU value increases from 68.21% to 82.23% after the feature reweighting module is introduced. Therefore, the dense convolution module and feature reweighting module improve the learning ability of the network for bone structure features in ultrasound images from two aspects of feature connection and importance understanding and effectively improve the performance of bone structure segmentation.Figure 8
Feature reweighting module network channel characteristics.As shown in Figure9, in order to quantitatively evaluate the accuracy of bone structure reconstruction based on ultrasonic image segmentation, agar phantom was further scanned by CT after ultrasonic acquisition to obtain the real three-dimensional structure of the femoral head.Figure 9
Segmentation of the bone structure in ultrasound images.As shown in Table4, the three-dimensional bone structure reconstructed from the ultrasound image is accurate. After obtaining the reconstructed three-dimensional model, the reconstructed bone structure is displayed by using stereo holography technology. In addition, VR/AR system further shows the augmented reality visualization results of the fusion of the real three-dimensional femoral head structure and the three-dimensional model reconstructed from the ultrasonic image. We need to reconstruct the segmented bone structure image directly, and the reconstruction speed is about 18 frames/second. In addition, the rendering speed of GPU and OpenGL is about 30 frames.Table 4
Three-dimensional bone structure reconstructed in ultrasound images.
DenseIOUSegmentationAccuracyConvolutionTransferUltrasound image1.370.461.30.551.21Feature1.293.51.252.141.3Bone structure5.272.654.143.424.03Segmentation2.855.762.211.32.37Phantom ultrasound1.073.623.541.732.58IOU value1.433.164.221.64.72


## 4.3. VR/AR Technology in Operation Teaching and Training

As shown in Figure10, digital technology can transmit this model to any place; VR can present the intuitive three-dimensional model and realize convenient and fast remote expert consultation. The application of AR/VR technology in the field of medicine has been initially formed, but there are still some shortcomings. The biggest problem of AR/VR technology is that the matching accuracy between the virtual model and real world still needs to be further improved, which may be one of the reasons why cardiothoracic surgery is relatively backward in AR/VR technology application compared with other majors.Figure 10
Transmission and application scope of VR technology.Different vision of VR device wearers will also cause the difference between the model and the real world. As shown in Figure11, intraoperative operation can cause tissue deformation, displacement, etc. In addition, the establishment of the VR three-dimensional model depends on imaging and computer science professionals, and it takes a long time. The ergonomics of VR equipment still needs to be improved, such as equipment power, wearing comfort, and other aspects. Long time wearing VR equipment may cause nausea and dizziness and increase the risk of surgery to a certain extent. At present, there is no special software for medical needs in VR devices, but commercial software is used in medical practice, and its potential risks are unknown.Figure 11
The difference between the model and the real world.


## 4.4. Discussion

AR/VR technology is a new type of holographic imaging technology after AR, VR, 3D printing, and other modern technologies. It combines the advantages of AR and VR technology. In addition, VR model is more realistic. It can be removed and replaced by coloring, transparency, or at will to get the desired model, which is more practical than the traditional printing model. Through the use of virtual simulation technology to build clinical scenarios and the unique comparative teaching method of clinical differential diagnosis experts, each case is divided into history collection, physical examination, auxiliary examination, examination results, differential diagnosis, treatment plan, and other functional modules, and through a large amount of clinical data collection, the data of diagnosis and treatment process are exchanged by text, sound, image, and other multimedia. The virtual clinical operation technology is integrated into the case, and the clinical skills and clinical thinking ability of medical students are comprehensively improved by using the online assessment and evaluation function of the system. AR/VR technology can meet the training of this skill and has repeatability. In the process of real-time teaching, the difficulty of real-time data processing can be solved. Some scholars have established a virtual three-dimensional reduction model of distal radius extension fracture, which further strengthens the promotion of bone setting manipulation and the mechanism research of manipulation effect. In the process of manipulation operation, we can clearly see that bone setting manipulation effect improves the displacement of the fracture end. Orthopedic surgery requires high aseptic conditions, so medical students will be limited in the operation observation. Although endoscopic technology is widely used, but the camera picture lacks a sense of orientation and space and can only see the anatomical structure in the picture, but can not observe the operator’s operation method of surgical instruments, resulting in medical students to lose interest in learning surgery, and orthopedic surgery gradually tends to be minimally invasive; it is difficult for medical students to further learn surgical operation skills. With the help of virtual technology, the above problems can be effectively solved by online live broadcast of surgery. AR/VR technology is a new type of holographic imaging technology that has emerged after modern technologies such as AR, VR, and 3D printing. It combines the advantages of AR and VR technology. In addition, the VR model is more realistic and can be obtained by coloring, transparent or arbitrary removal, and replacement. The desired model is more practical than the traditional printing model. Through the use of virtual simulation technology to construct clinical scenarios and the unique comparative teaching method of clinical differential diagnosis experts, each case is divided into multiple functional modules such as medical history collection, physical examination, auxiliary examination, examination results, differential diagnosis, and treatment plan. Through a large amount of clinical data collection, the information of the diagnosis and treatment process is displayed to learners in the form of text, sound, image, and other multimedia interaction, and virtual clinical operation technology is integrated into the case, and further, through the online assessment and evaluation comparison in the application system function, the clinical skills and clinical thinking ability of medical students are comprehensively improved. AR/VR technology can meet the training of this skill, and it is repetitive. A new solid fracture model can be developed by analyzing the solid fracture model combined with data processing technology. During the manual reduction process, the synchronization of the manual effect information is completed in real time, which solves the practical difficulties of manual reduction teaching. Some scholars have established a virtual three-dimensional reduction model of the distal radius extension fracture, which has further strengthened the promotion of the orthopedic technique and the study of the mechanism of the maneuver effect. During the manipulation, the effect of the orthopedic technique can be clearly seen to improve the fracture end and the displacement situation. Orthopedic surgery requires high aseptic conditions, and medical students will be restricted when performing surgical observations. Although laparoscopic technology is widely used, the camera images lack a sense of orientation and space and can only see the anatomical structure in the image, but cannot observe the operation method of the surgeon’s surgical instruments, causing medical students to lose interest in learning surgery; moreover, orthopedic surgery is gradually becoming more minimally invasive, and it is difficult for medical students to further learn surgical techniques. With the help of virtual technology, the abovementioned problems can be effectively solved through online live broadcast of surgery.


## 5. Conclusions

It will realize the preoperative planning, the choice of the surgical path, the coincidence of the model and human body, the display of the virtual needle path, etc., which are still not well applied in clinic, but the emergence of AR/VR technology can well complete the above application. Although the application of AR/VR technology in the medical field is just in the beginning, it has unlimited prospects. On the basis of previous research results, we can look forward to the bright future of AR/VR technology in surgery. First of all, we should continue to use VR as a surgical training tool, and at the same time, we should use more advanced technology to detect the surgeon’s technology or reduce the difference between the virtual environment and the real surgical environment. In addition, the wide clinical application of AR/VR technology in surgery will accelerate the development of remote surgery. With the rapid evolution of 5G, we believe this intelligent surgical environment will come soon. In the future, AR/VR technology may bring disruptive changes in medical training, disease diagnosis, doctor-patient communication, clinical diagnosis, and treatment and promote the rapid development of medicine.



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*Source: 9998427-2021-06-08.xml*