The effectiveness of a crystalline natural barrier in providing sealing capabilities is based on the behavior of numerous fractures and their intersections within the rock mass. It is important to evaluate the evolving characteristics of fractured rock, as the hydro-mechanical coupled processes occurring through these fractures play a dominant role. KAERI is actively developing a true tri-axial compression test system and concurrently conducting hydro-mechanical experiments using replicated fractured rock samples. This research is focused on a comprehensive examination of coupled processes within fractures, with a particular emphasis on the development of true tri-axial testing equipment. The designed test system has the capability to account for three-dimensional stress conditions, including vertical and both maximum and minimum horizontal principal stresses, realizing the disposal conditions at specific underground depths. Notably, the KAERI-designed test system employs the mixed true tri-axial concept, also known as the Mogi-type, which allows for fluid flow into fractures under tri-axial compression conditions. This system utilizes a hydraulic chamber to maintain constant stress in one direction through the application of oil pressure, while the other two directional stresses are applied using rigid platens with varying magnitudes. Once these mechanical stress conditions are established, control over fluid flow is achieved through the rigid platens in contact with the specimen section. This pioneering approach effectively replicates in-situ mechanical conditions while concurrently observing the internal fluid flow patterns within fractures, thereby enhancing our capacity to study these coupled phenomena. As future research, numerical modeling efforts will be proceeding with experimental data-driven approaches to simulate the coupled behavior within the fractures. In these numerical studies, two distinct fracture geometry domains will be generated, one employing simplified rough-walled fractures and the other utilizing mismatched rough-walled fractures. These investigations mark the preliminary steps in the process of selecting and validating an appropriate numerical model for understanding the hydro-mechanical evolution within fractures.

It is crucial to understand the hydro-mechanical behavior of rock mass to assess the performance of natural barriers. As rock fractures serve as both mechanically weak planes and prominent pathways for hydraulic flow, they significantly influence the hydro-mechanical behavior of the rock mass. Hence, understanding the characteristics of rock fractures is necessary to analyze the long-term behavior of natural barriers. In particular, fracture apertures are crucial parameters directly associated with groundwater flow and consequently hold significant importance in determining the hydro-mechanical behavior of natural barriers. Fracture apertures are defined as mechanical and hydraulic apertures, and various studies have been conducted to measure and analyze them. However, direct measurement of mechanical aperture according to changes in normal stress is known to be a challenging task. For this reason, there has been a scarcity of direct comparative findings between mechanical and hydraulic apertures under various normal stress conditions. This study aims to analyze the characteristics of the mechanical and hydraulic apertures according to changes in normal stress based on experimental results. A digital analysis technique using a pressure film image was applied to analyze the mechanical aperture characteristics of the fracture. This technique can be applied by performing a pressure film compression test and a normal stiffness test on a fracture specimen, and has the advantage of being able to derive mechanical apertures under various normal stress conditions. The hydraulic aperture characteristics of the fracture were analyzed based on Cubic law after measuring the flow rate by performing a constant pressure injection test under triaxial compression conditions. By applying various confining pressures, it was possible to examine the hydraulic apertures according to changes in normal stress conditions. Through the experimental results, the relationship between the mechanical and hydraulic apertures of the fracture was summarized under various normal stress conditions. In addition, the experimental results were used to examine the applicability of various empirical equations for mechanical and hydraulic apertures proposed in previous studies. The characteristics of the fracture aperture resulting from this study are significant because they are required in the hydro-mechanical model of natural barriers. Future studies will entail further experiments, with the objective of establishing novel relationships based on the accumulation of experimental data.

Discontinuities exert great influence on the thermal, hydraulic, and mechanical behavior of rock mass. Rock joint is one of the most frequently encountered discontinuities in many engineering applications, such as tunnel, rock slope and repository for high level radioactive waste. Therefore, the effects of rock joint should be thoroughly investigated in various aspects. Rock joint has gone through many geological processes and its behavior can be characterized by many properties. Among them, geometric properties, such as joint roughness, aperture, and contact area can affect mechanical and hydraulic properties and vice versa. Therefore, accurate understanding and characterization of the geometric properties are of importance. Generally, the geometric properties of a joint are obtained or estimated using the surface height or elevation, which could be measured by various contact or noncontact methods. Then, the coordinates of the surfaces are used to calculate several parameters, for instance roughness indexes and mechanical aperture, in a quantitative manner. This paper is a part of SKB task force project that aims to evaluate the geometric properties of rock joints and to analyze the hydromechanical behavior within a rough joint considering the properties. Four pairs of joint surfaces were laser-scanned in order to obtain coordinates of the surfaces and then the coordinates were used to calculate the roughness, directional roughness, aperture, and spatial correlations. At the same time, fluid flow within a rough joint were simulated by a commercial FEM code, considering the variation of aperture space due to normal load. Flowrate, flow path, and channelization were investigated in an aperture scale. Since rock mass consists of several joints and/or joint sets, characterization of a single rock joint can be utilized for analyzing the behavior of rock mass as a reference.

In KAERI, a site descriptive model for stress field estimation had already been constructed by using integrated field data within KURT site scale. A sub-divided rock block domain containing major fracture zones has spatial rock mass and fault properties. The properties were decided based on the rock classification results of several borehole investigations. Modeling for maximum and minimum horizontal stress field estimation was performed and compared with the in-situ data. As a result, a depth-dependent stress ratio was adopted to obtain numerical results closer to actual in-situ data. Although the results were suitable at a relatively low depth (~500 m), there is still some deviation trend at a deep depth. This study aims to improve these modeling results by incorporating not only depth-dependent stress ratio but also changes in rock mass properties along the depth. The deep borehole of DB2 in the KURT site indicated fracture distribution corresponding to the property changes. Natural fractures are typically randomly oriented, and the fracture frequency decreases with increasing depth. The increase in P-wave velocity log data accompanies these features. A discrete fracture network (DFN) model can be used to simulate fractured rock explicitly, but DFN modeling is not feasible for site scale analysis because of its numerical efficiency. Therefore, as a preliminary model in this study, the effect of fracture distribution was considered by substituting the influence for the depth-dependent property. The properties were estimated from the fracture frequency and P-wave velocity log data. The influence of elastic modulus and density on the site stress field was dominant, with decreasing the deviation trend between modeling and in-situ data at a deep depth. Considering that the depth of the repository construction is within about 500 m, it may not be necessary to consider the change of rock properties with depth. However, it was determined that the rock property effect might need to be considered when the loading conditions change due to subsidence in the long-term evolution scenario. Continuously, this site descriptive modeling will be interdependently conducted with a representative DFN block model for deriving equivalent properties in fractured rock.

The distribution characteristics of rock fractures determine the hydro-mechanical behavior of natural barriers. Rock fractures are defined by various parameters, which are analyzed as the probability distribution from observation results by surveying the exposed rock surface or borehole. The size is known to have the most uncertainty among the fracture parameters because it cannot be directly measured. Therefore, various estimation methods have been proposed for fracture size distribution using the fracture traces observable on the rock surface. However, most methods are based on a planar survey area, limiting their applicability to the underground research laboratory (URL) excavated in the form of tunnels. This study aims to review a method that can be applied to estimate the size distribution of fractures in deep rock masses at the URL site. The estimation method using the joint center volume (JCV) has recently been extended to be applicable regardless of the geometry of the survey area, which means that it can be applied to the URL site with complex structures. To apply the JCV-based estimation method to non-planar survey areas, JCV calculation using Monte Carlo simulation and estimation of fracture size distribution using the maximum likelihood method are required. In this study, we applied the JCV-based estimation method to a tunnel-shaped survey area to examine its applicability to the URL site. The error rates were analyzed when there were fracture sets with various orientations, size distributions, and maximum fracture sizes in the rock mass, and it was found to be less than 10% in all cases. This result indicates that the JCV-based estimation method can be used to estimate the fracture size distribution of the surrounding rock mass if accompanied by a reliable survey of fracture traces on the tunnel surface inside the URL site. Also, since there are no restrictions on the geometry of the survey area, we can continuously update the estimation results during the URL excavation process to increase reliability. The fracture size distribution is essential for constructing the discrete fracture network (DFN) model of the rock mass units at the URL site. In the future, the uncertainty for the fracture size in the DFN model is expected to be reduced by applying the JCV-based estimation method.

Numerical modeling and scenario composition are needed to characterize the geological environment of the disposal site and analyze the long-term evolution of natural barriers. In this study, processes and features of the hydro-mechanical behavior of natural barriers were categorized and represented using the interrelation matrix proposed by SKB and Posiva. A hydro-mechanical coupled model was evaluated for analyzing stress field changes and fracture zone re-activation. The processes corresponding to long-term evolution and the hydro-mechanical mechanisms that may accompany critical processes were identified. Consequently, practical numerical methods could be considered for these geological engineering issues. A case study using a numerical method for the stability analysis of an underground disposal system was performed. Critical stress distribution regime problems were analyzed numerically by considering the strata’s movement. Another case focused on the equivalent continuum domain composition under the upscaling process in fractured rocks. Numerical methods and case studies were reviewed, confirming that an appropriate and optimized modeling technique is essential for studying the stress state and geological history of the Korean Peninsula. Considering the environments of potential disposal sites in Korea, selecting the optimal application method that effectively simulates fractured rocks should be prioritized.

The hydro-mechanical behavior of rock mass in natural barriers is a critical factor of interest, and it is mainly determined by the characteristics of the fractures distributed in the rock mass. In particular, the aperture and contact area of the fractures are important parameters directly related to the fluid flow and significantly influence the hydro-mechanical behavior of natural barriers. Therefore, it is necessary to analyze the aperture and contact area of fractures distributed in potential disposal sites to examine the long-term evolution of the natural barriers. This study aims to propose a new technique for analyzing the aperture and contact area using the natural fractures in KURT (KAERI Underground Research Tunnel), an underground research facility for the deep geological disposal of high-level radioactive waste. The proposed technique consists of a matching algorithm for the three-dimensional point cloud of the upper and lower fracture surfaces and a normal deformation algorithm that considers the fracture normal stiffness. In the matching process of upper and lower fracture surfaces, digital images obtained from compression tests with pressure films are used as input data. First, for the primary matching of the upper and lower fracture surfaces, an iterative closest point (ICP) algorithm is applied in which rotation and translation are performed to minimize the distance error. Second, an algorithm for rotation about the x, y, and z axes and translation in the normal direction is applied so that the contact area of the point cloud is as consistent as possible with the pressure film image. Finally, by applying the normal deformation algorithm considering the fracture normal stiffness, the aperture and contact area of the fracture according to the applied normal stress are derived. The applicability of the proposed technique was validated using 12 natural fractures sampled from KURT, and it was confirmed that the initial apertures were derived similarly to the empirical equation proposed in the previous study. Therefore, it was judged that the distribution of apertures and contact areas according to applied normal stress for laboratory-scale fractures could be derived through the technique proposed in this study.

With the development of artificial intelligence, large data and cloud computing technologies, the global trend of industrie 4.0 is coming. The key factor is IT convergence of software and hardware. From large corporations to small and medium-sized enterprises, IT companies must realize internationalization as a survival strategy effectively in the global market-based economy (Wilden & Gudergan, 2015). Recently, dynamic capability is the ultimate source of competitive advantage. Dynamic capability is the ability to integrate, relocate, and form new capabilities of an organization's resources to adapt to changing environments (Barreto, 2010; Fallon-Byrne & Harney, 2017; Teece, 2012). On the other hand, entrepreneurship is closely related to various factors such as dynamic adaptation of company, adaptation, response, and innovation to changing environments (Arend, 2013). From this viewpoint, the aim of this paper is to examine the effect of entrepreneurship on firm's dynamic capabilities and the impact of dynamic capability on business performance (Etemad, 2004; Laukkanen, Nagy et al. 2013). In addition, we explore whether the effects vary across company type, namely those of soft and hardware companies. In this model, dynamic capabilities consist of three sub-dimensions; opportunity exploration capability (DC_O), resource acquisition capability (DC_A), and resource reconfiguration capability (DC_R) (Barreto, 2010; Knight, 2000; Teece, 2007). Also, business performance is divided into financial (FP) and non-financial performance (NFP). Incorporating entrepreneurship and dynamic capabilities in the same model, the findings of this study will contribute to give a more comprehensive view by showing the entrepreneurship and dynamic capabilities mays explain business performance. For this purpose, this study examines the structural relationship between entrepreneurship, dynamic capability, and business performance and the moderating role of company type. The data were collected from 209 CEOs of soft and hardware SMEs and analyzed with SPSS 21.0 / WIN and SmartPLS 3.0 statistical package. Based on previous studies, we propose following hypotheses. H1: Entrepreneurship has a positive effect on dynamic capabilities. H1-1: Entrepreneurship has a positive effect on opportunity exploration capability (DC_O) of dynamic capabilities. H1-2: Entrepreneurship has a positive effect on resource acquisition capability (DC_A) of dynamic capabilities. H1-3: Entrepreneurship has a positive effect on resource reconfiguration capability (DC_R) of dynamic capabilities. H2: Dynamic capabilities have a positive effect on business performance. H2-1: Dynamic capabilities have positive effects on financial performance. H2-2: Dynamic capabilities have positive effects on non-financial performance. Figure 1 displays the results of analysis of structural equation modeling (SEM). The findings and summaries are as follows. First, entrepreneurship has a positive effect on DC_O, DC_A, and DC_R. DC_O has a positive effect on NFP, but does not on FP. Second, DC_A has a positive effect on both FP and NFP(Arend, 2014; Wang and Ahmed 2007). Third, the moderating test shows that the relationships between entrepreneurship and dynamic capabilities, and DC_R and FP and NFP are significantly different between across soft and hardware SMEs. This study proposed and examined the entrepreneurship – dynamic capability – business performance framework in SMEs IT context. The findings of this study reveal that entrepreneurship contributes to enhance dynamic capabilities, and in turn increase financial and non-financial performance (Soriano& Dobon, 2009). More importantly, this study integrates entrepreneurship theory and resource-based view and shows that venture firm’s business performance will be maximized when CEOs have a high entrepreneurship and build dynamic capabilities. The findings also shows that in particular, it is very noteworthy that non-financial performance is enhanced by dynamic capabilities. In summary, this study shows that SMEs' entrepreneurship and dynamic capabilities can increase the business performance of companies as the IT industry is fiercely competing with domestic companies as well as international companies (Amazon, IBM, etc.).

Introduction In recent times, mass customization strategy has been actively adapted even in the food service industry, which provides services wherein consumers select the main ingredients of the food they order according to their preference. In this study, we examine the effect of mass customization strategies perceived by consumers in the food service industry. We also includes the external and internal environmental factors stimuli surrounding the situation of purchasing customized food items to better predict how consumer’s perceived value of mass customization might be formed within the context of service industry. Evidence shows that consumers’ perceived value is high for mass customization in food consumption service compared to food service for a fixed menu. The findings further suggest that this effects of mass customization on consumer perception is moderated by social influence (group vs. individual) and food type (utilitarian vs. hedonic). Theoretical Development Recent research in the field of mass customization has demonstrated that the advantage of designing consumer’s own products is in increasing consumer's perceived benefits while engaging in the customization of tangible products. These studies have shown that the mass customization provides consumers with a utilitarian value due to the purchase of optimized products that meet their individual needs and various values that are embedded in the customization process, such as hedonic value, self-expressive value, and creative achievement (Merle, Chandon, Roux, & Alizon, 2010; Yoo & Park, 2016), and that this value recognition leads to positive attitudes and behavioral responses such as high willingness to pay (Franke, Keinz, & Steger, 2009; Schreier, 2006), purchase intent, and loyalty (Yoo & Park, 2016). However, whereas research on mass customization focusing on tangible products has been actively conducted, research in the field of intangible services, is still lacking in two respects. First, there has been very little discussion of the effectiveness of mass customization strategies in the food service industry. Specifically, based on the stimuli-organism-response (S-O-R) framework, which states that environmental stimuli (S) lead to the formation of a customer perception (O) that induces consumers’ behavioral responses (R) (Mehrabian & Russell, 1974), existing research focused on the relationship of customer’s behavioral response to mass-customized food service (S-R relationship) (Kuo & Cranage, 2010; Wolf and Zhang, 2016), failing to embrace S-O relationship that focuses on how mass customization differs from a standard system in terms of how consumers perceive value. Considering that mass customization services can be regarded as a form of customer engagement strategy (Chathoth et al., 2014; Chathoth et al., 2016), it can be assumed that mass customization in services can induce positive consumer perception. Second, little research has yet examined situational factors that affect consumer response in purchasing mass customization of products/service. Considering that service environments play a significant role in service delivery by strengthening customer perceptions and retention (Baker, Parasuraman, Grewal, & Voss, 2002; Sherman, Mathur, & Smith, 1997), it is necessary to identify the internal and external environmental factors that limit or enhance consumers’ perceived value of the mass customization for effective implementation of the mass customization strategy. The aim of the present research is to empirically examine the effects of mass customization on consumer responses. It is hypothesized that consumers’ perceived value might be high for mass customization in food consumption service (compared to food service for a fixed menu) (H1), which is consistent with previous literature on consumer responses to mass customization in tangible. Furthermore, the current research further includes various environmental stimuli surrounding the situation of purchasing customized food items to better predict how consumer’s perceived value of mass customization might be formed within the context of service industry. Based on the assumption that (a) people's choice of consumption is affected by the expectations of how others evaluate their decisions (Ariely & Levav, 2000; Calder & Burnkrant, 1977) and that (b) consumers are more concerned about social norms and therefore make similar choices to blend in resulting in uniformity at the group level (Tice, Butler, Muraven, & Stillwell, 1995), it is expected that consumers sometimes feel compelled to refrain from choosing favorites because of how they expect to be perceived by others, hindering consumer’s benefits of mass customization. In addition, there are two food types based on the goal of consuming food: utilitarian food and hedonic food (craving for sweetness, e.g., desserts) (Wansink, Ittersum, & Painter, 2004; 2005). In pursuing the hedonic goal, the consumer tendency to engage in various behaviors is strengthened by the desire to express one’s personality to others (Ariely & Levav, 2000; Ratner & Kahn, 2002). Accordingly, in the present research, we explore the perceived value of mass customization moderated by social influence (H2), and food type (H3). In this model, social influence (group vs. individual), which is the factor outside the scope of customizing process, is regarded as an external variable and food types (utilitarian vs. hedonic), divided according to the purpose of food consumption, as an internal variable. Method We used a 2 (customization: low vs. high) × 2 (social influence: individual vs. group) between subject experiment conducted on the subjects regarding two types of food service: utilitarian food (main course) and hedonic food (dessert). We assigned 208 participants randomly to one of four conditions. Participants were asked to imagine they were visiting the high customized restaurant with their colleague together (vs. alone) that provide high customized service (vs. low customized service) and saw a menu for a food item. Modified from Kuo and Cranage (2010) study, two level of customized menu scenarios were used in this study. In the high customization scenario, participants are told that they were in a restaurant where they were offered to customize their dishes with choices of ingredients. In the low customization condition, participants were told that they were in a restaurant where they ordered among fixed menu items. Based on pretest result, we used pasta, which is entrée for the utilitarian food, and use ice-flake, which is dessert for the hedonic food. After reading the scenario, participants provide their perceived value of mass customization ratings of the service process. Results and Conclusion First, an analysis of variance (ANOVA) revealed a significant effect of mass customization demonstrating that on perceived value, participants who read mass customization service condition had a higher perceived value on their food than participants in the fixed menu condition (H1). Second, in order to examine whether social influence (H2) and food type (H3) moderate the effect of mass customizatino on consumer perceptions, a moderated moderation model was performed a bootstrapping procedure with 5000 samples using the PROCESS model 3 (Hayes, 2016). The result revealed a significant three-way interaction effect among level of customization (high vs. Low), social influence (group vs. individual), and food types (utilitarian vs. hedonic). As the level of customization increases, the overall perceived value increases; however, it is confirmed that, when making decisions about food in a group situation, there are restrictions on perceiving the value that the consumer can customize and feel as compared to the individual situation. Finally, impact of social influence on the perceived value of customization is moderated by food type (hedonic vs. utilitarian). In other words, in hedonic food consumption situation, the modeartion effect of social influence on the perceived value of customization is weakened. Consumers are more likely to appreciate the process and consider it more palatable when they use mass customization service in restaurant. However, when people are conscious of the presence of others, the act of selecting food ingredients according to one’s own preference is restricted. Therefore, even if customized food is ordered in the presence of the group, its perceived value will be as lower than that of a fixed menu. In addition, when people use mass customization service in hedonic food consumption situations, regardless of group influence, they perceive that the value of customized menu is higher than that of the fixed menu. We expect that the study findings and framework will provide practical and theoretical implications such as the development of theories on food service situations, as well as aid restaurants in establishing marketing strategies. In addition, identifying internal and external environmental factors that limit consumers’ perceived value of mass customization will enable restaurants to find a suitable menu composition method to enhance and maintain customers’ perceived value and build a promotional strategy accordingly.

As the global cosmetics market becomes more competitive, cosmetics firms need to be more market-oriented. Consumers purchase cosmetics products not only based on product-related attributes (e.g., function) but also for non-product-related reasons such as novelty and a pursuit of variety. They are exposed and have access to a variety of choices imported from other countries, which further complicates decision-making. Globalization offers great opportunities for marketers as it may help expand the horizon of the market beyond the domestic boundary. Given that the market is becoming more competitive, it is imperative to understand what influences purchase decisions of global consumers. This study considers and examines extended susceptibility to global consumer culture (Extended SGCC) and its effect on affective commitment, which in turn influences behavioral commitment and loyalty. We consider four elements of extended SGCC: conformity to consumer trend, social prestige, quality perception, and corporate social responsibility. In addition to examining the structural relationships among the variables, we test whether country of origin (COO) moderates the proposed relationships. In order to test the model, we collected data from the purchasers of botanical cosmetics products that came from several different countries. A total of 798 users participated in the survey (425 users of domestic brands and 373 users of foreign brands). We performed several analyses related to the measurement model such as reliability analysis (Cronbach’s alphas), confirmatory factor analysis, and correlations analysis. Using SPSS 21.0 and AMOS 21.0, we estimated the structural model. The overall model fit indices include: χ2=1118.934 with df=239, p=0.000; GFI=0.884; AGFI=0.855; NFI=0.924; CFI=0.934; RMSEA=0.068; RMR=0.069. The study finds that all elements of SGCC, with the exception of social prestige, have a significant influence on affective commitment. Specifically, conformity to consumer trend is found to have a significant effect on affective commitment. This means that consumers who conform to the global trend tend to have a higher level of commitment. One implication is that cosmetics firms may want to communicate to the consumers that their products fit the lifestyle corresponding to the global trend. Contrary to our expectation, social prestige is not found significantly related to affective commitment. It seems that social prestige is not an important factor in choosing botanical cosmetics products. This is understandable because, unlike some prestige products that consumers wear or use to be associated with their image or perceived quality (e.g., car, handbag), consumers may not purchase botanical cosmetics products to upgrade their social status. As expected, quality perception has a significant positive effect on affective commitment. The study shows that quality perception has the most significant impact on affective commitment. Corporate social responsibility (CSR) is also found to have a significant impact on affective commitment. The finding suggests that companies should be or remain active in taking initiatives that advance social welfare. Our study shows that both affective and behavioral commitments are positively related to customer loyalty. Behavioral commitment, which consists of items representing purchase tendency, has a greater influence on loyalty than affective commitment. We anticipated that country of origin (COO) would moderate the proposed relationships. We find no significant moderating effect of COO. This can be interpreted that the structural relationships are upheld regardless of COO. It seems that global consumers evaluate foreign brands in the same manner as they do domestic brands. This suggests that cosmetics firms may want to be careful in differentiating their strategies based on countries as the return on investment may not be as handsome as they thought and global consumers may have more similarities than differences with respect to how they evaluate and purchase cosmetics products.

구강 및 두경부 암의 방사선치료 시 치료 범위에 피부를 포함하는 경우가 많으며 이때 볼루스의 사용이 빈번해진다. 특히 턱 부분의 요철로 인하여 환자의 적용 시 선량 불확실성을 제공한다. 본 연구에서는 3D Printing을 이용하여 Gel 볼루스와 Poly lactic acid(PLA), Silicon을 적용한 환자 맞춤형 볼루스를 제작하여 물성 특성을 확인하고, 제작된 볼루스와 치료계획의 불일치성을 확인하며, 실제 방사선 선량 전달시 발생하는 선량불확실성을 측정하였다. 그 결과 일반적인 요철 부위에는 PLA 재질의 볼루스가 안정적이며, 요철이 심하거나 환자의 체형이 자주 바뀔 수 있는 환자의 경우 Silicon 재질의 볼루스가 유용할 것으로 사료된다.

다양한 촬영 조건의 CT 감쇠 지도가 PET 영상에 영향을 미치는지 알아보기 위하여 다양한 kVp와 mA 조건에서 Uniformity phantom 영상의 신호 강도 (SI; Signal Intensity)와 표준 섭취율 계수 (SUV; Standardized Uptake Value)를 측정하고, CTDI(Computed Tomography Dose Index)를 통해 각 조건에 따른 피폭선량을 측정하였다. 또한 동일한 조건에서 Resolution phantom의 반치폭 (FWHM; Full Width at Half Maximum)을 측정하여 CT의 kVp와 mA에 따른 PET 영상의 화질 변화에 대하여 정량적으로 알아보고자 하였다. 연구 결과, CT의 촬영 조건은 PET 영상에는 영향을 주지 않는 것으로 나타났으나, CT의 촬영 조건이 감소하게 되면 방사선 피폭이 감소하게 되지만 영상에 영향을 미치게 되므로 향후 진단이 가능한 CT 화질을 유지하면서 방사선 피폭을 최소화할 수 있는 양전자 방출 단층 촬영 (PET/CT; Positron Emission Tomograph y / Computed Tomography)의 촬영 조건에 대한 연구가 지속적으로 되어야 할 것이다.

99mTc을 이용하는 검사를 받고 CT 검사를 진행했을 때 CT 영상에 99mTc이 미치는 변화에 대하여 정량적으로 알아보고자 하였다. Resolution phantom과 Water phantom에 99mTc 740 MBq를 주입 전· 후 80 kVp와 120 kVp로 관전압을 변화시켜 CT Scan하였다. 연구결과 99mTc 주입 전·후 신호강도는 각각 0.173, 0.241의 감소 하였으며, 공간분해능은 각각 0.090, 0.109로 증가하였다. CT 촬영을 99mTc의 유효 반감기를 고려하여 99mTc 의 감마선이 CT에 영향을 미치지 않도록 일정한 시간 후 진행함으로 영상의 변화를 줄일 수 있을 것으로 사료된다.