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In 2016, the International Commission on Radiological Protection (ICRP) launched Task Group 103 (TG 103) for the explicit purpose of developing a new generation of adult and pediatric reference computational phantoms, named ‘mesh-type reference computational phantoms (MRCPs)’, that can overcome the limitations of voxel-type reference computational phantoms (VRCPs) of ICRP Publications 110 and 143 due to their finite voxel resolutions and the nature of voxel geometry. After completing the development of the adult MRCPs, TG 103 has started the development of pediatric MRCPs comprising 10 phantoms (male and female versions of the reference newborn, 1-year-old, 5-year-old, 10-year-old, and 15-year-old). As part of the TG 103 project, within the present study, the skeletal systems, one of the most important and complex organ systems of the body, were developed for each phantom age and sex. The developed skeletal systems, while closely preserving the original bone topology of the pediatric VRCPs, present substantial improvements in the anatomy of complex and/or small bones. In order to investigate the dosimetric impact of the developed skeletons, the average absorbed doses and the specific absorbed fractions for radiosensitive skeletal tissues (i.e. active marrow and bone endosteum) were computed for some selected external and internal exposure cases, which were then compared with those calculated with the skeletons of pediatric VRCPs. The comparison result showed that the dose values of the pediatric MRCPs were generally similar to those of the pediatric VRCPs for highly penetrating radiations (e.g. photons >200 keV); however, for weakly penetrating radiations (e.g. photons ⩽200 keV and electrons), significant differences up to a factor of 140 were observed.

In line with the activities of Task Group 103 under the International Commission on Radiological Protection (ICRP), the present study was conducted to develop a new set of alimentary tract organs consisting of the oral cavity, oesophagus, stomach, small intestine, and colon for the newborn, 1 year-old, 5 year-old, 10 year-old, and 15 year-old males and females for use in the pediatric mesh-type reference computational phantoms (MRCPs). The developed alimentary tract organs of the pediatric MRCPs, while nearly preserving the original topology and shape of those of the pediatric voxel-type reference computational phantoms (VRCPs) of ICRP Publication 143, present considerable anatomical improvement and include all micrometre-scale target and source regions as prescribed in ICRP Publication 100. To investigate the dosimetric impact of the developed alimentary tract organs, organ doses and specific absorbed fractions were computed for certain external exposures to photons and electrons and internal exposures to electrons, respectively, which were then compared with the values computed using the current ICRP models (i.e. pediatric VRCPs and ICRP-100 stylised models). The results showed that for external exposures to penetrating radiations (i.e. photons >0.04 MeV), there was generally good agreement between the compared values, within a 10% difference, except for the oral mucosa. For external exposures to weakly penetrating radiations (i.e. low-energy photons and electrons), there were significant differences, up to a factor of ∼8300, owing to the geometric difference caused by the anatomical enhancement in the MRCPs. For internal exposures of electrons, there were significant differences, the maximum of which reached a factor of ∼73 000. This was attributed not only to the geometric difference but also to the target mass difference caused by the different luminal content mass and organ shape.

Cranial nerve ganglia, which are prone to viral infections and tumors, are located deep in the head, so their detailed anatomy is difficult to understand using conventional cadaver dissection. For locating the small ganglia in medical images, their sectional anatomy should be learned by medical students and doctors. The purpose of this study is to elucidate cranial ganglia anatomy using sectioned images and three-dimensional (3D) models of a cadaver.One thousand two hundred and forty-six sectioned images of a male cadaver were examined to identify the cranial nerve ganglia. Using the real color sectioned images, real color volume model having a voxel size of 0.4 × 0.4 × 0.4 mm was produced.The sectioned images and 3D models can be downloaded for free from a webpage, anatomy.dongguk.ac.kr/ganglia. On the images and model, all the cranial nerve ganglia and their whole course were identified. In case of the facial nerve, the geniculate, pterygopalatine, and submandibular ganglia were clearly identified. In case of the glossopharyngeal nerve, the superior, inferior, and otic ganglia were found. Thanks to the high resolution and real color of the sectioned images and volume models, detailed observation of the ganglia was possible. Since the volume models can be cut both in orthogonal planes and oblique planes, advanced sectional anatomy of the ganglia can be explained concretely.The sectioned images and 3D models will be helpful resources for understanding cranial nerve ganglia anatomy, for performing related surgical procedures.

In the Visible Korean, serially sectioned images with real color and high resolution have been prepared from four cadaveric subjects: male whole body, female whole body, male head, and female pelvis. Recently, segmented images of the female whole body were manufactured, permitting the distribution of the complete four data sets. The purpose of this report was to promote the applications of sectioned and segmented images from the Visible Korean by announcing them. Reduced image data were loaded to self-developed browsing software; using the browsing software, the contents could be quickly grasped and evaluated by other investigators. The four data sets were compared to disclose the individual merits and demerits. The sectioned and segmented images showed the possibility to be used to reconstruct the stereoscopic volume and surface models of body structures. The Visible Korean is expected to contribute to the interactive simulation of medical learning and clinical practice.

Objective To provide an anatomical atlas made of serially sectioned images of a female cadaver that clearly demonstrated the pudendal nerve. Materials and Methods The courses of the pudendal nerve, internal pudendal artery, and internal pudendal vein were observed on the sectioned images of a female cadaver. The spatial relationship between the nerve and blood vessels was interpreted. Results Traces of the structures on the sectioned images showed that the sources of the sciatic and pudendal nerves were the fourth lumbar nerve to the second sacral nerve and the second to the fourth sacral nerves, respectively. As the borderline, the second sacral nerve showed a remarkable variation. The pudendal nerve gave off the internal rectal nerve proximal to the pudendal canal and it gave off the muscular branch to the urogenital triangle in the pudendal canal. It was divided into the posterior labial nerve and the dorsal nerve of clitoris distal to the pudendal canal. Inside the pudendal canal, the internal pudendal vein, internal pudendal artery, and pudendal nerve were arranged from superomedial to inferolateral order. In other words, the pudendal nerve was the farthest from the uterus. Conclusion The sorted sectioned images with labels, accompanied by the schematic drawings, could serve as references for interpreting clinical images and conducting procedures related to pudendal nerve conditions.

SUMMARY: In Southern Medical University, China, 1,200 medical students study neuroanatomy every year, whereas in Ajou University, Korea, only 45 medical students study neuroanatomy. The considerable difference of student numbers results in differences in educational situations. The purpose of this study was to investigate desirable neuroanatomy education methods for large and small numbers of students. The situations of neuroanatomy education in China and Korea were compared systematically. With a questionnaire survey, positive comments and recommendations for their counterparts were collected from the medical students (168 Chinese and 41 Koreans) and anatomists (6 Chinese and 3 Koreans). By reviewing the opinions, the Chinese and Korean anatomists could learn from each other to improve their strong points and make up for the weak points. The results also disclosed the common problems of neuroanatomy education, which could be relieved by developing the fitting book and the self-learning tools, such as lecture videos and stereoscopic computer models.

Background: In physical anthropology, bone landmarks are palpated in living humans for the identification of corresponding skin landmarks and exact biometry. The purpose of this study is to help comprehend the locations and depths of representative bone landmarks all over the body. Materials and methods: The sectioned images of a male cadaver’s whole body were used to build a volume model, which was continuously peeled at 1 mm thicknesses to disclose 27 selected landmarks in the anterior, lateral, or posterior views. Results: The captured views of peeled volume models along with the labels of the bone landmarks were loaded to browsing software that was distributed for free. The browsing software containing the peeled volume models will enhance convenient studying of the bone landmarks. Conclusions: With the knowledge of bone landmarks, investigators would be able to attain more accurate measurements between skin landmarks.

Realistic two-dimensional (2D) and three-dimensional (3D) applications for anatomical studies are being developed from true-colored sectioned images. We generated advanced-sectioned images of the entire male body and verified that anatomical structures of both normal and abnormal shapes could be visualized in them. The cadaver was serially sectioned at constant intervals using a cryomacrotome. The sectioned surfaces were photographed using a digital camera to generate horizontal advanced-sectioned images in which normal and abnormal structures were classified. Advanced-sectioned images of the entire male body were generated. The image resolution was 3.3 × 3.3 fold better than that of the first sectioned images obtained in 2002. In the advanced-sectioned images, normal and abnormal structures ranging from microscopic (≥0.06 mm × 0.06 mm; pixel size) to macroscopic (≤473.1 mm × 202 mm; body size) could be identified. Furthermore, the real shapes and actual sites of lung cancer and lymph node enlargement were ascertained in them. Such images will be useful because of their true color and high resolution in digital 2D and 3D applications for gross anatomy and clinical anatomy. In future, we plan to generate new advanced-sectioned images of abnormal cadavers with different diseases for clinical anatomy studies.

When performing deep brain stimulation (DBS) of the subthalamic nucleus, practitioners should interpret the magnetic resonance images (MRI) correctly so they can place the DBS electrode accurately at the target without damaging the other structures. The aim of this study is to provide a real color volume model of a cadaver head that would help medical students and practitioners to better understand the sectional anatomy of DBS surgery. Sectioned images of a cadaver head were reconstructed into a real color volume model with a voxel size of 0.5 mm × 0.5 mm × 0.5 mm. According to preoperative MRIs and postoperative computed tomographys (CT) of 31 patients, a virtual DBS electrode was rendered on the volume model of a cadaver. The volume model was sectioned at the classical and oblique planes to produce real color images. In addition, segmented images of a cadaver head were formed into volume models. On the classical and oblique planes, the anatomical structures around the course of the DBS electrode were identified. The entry point, waypoint, target point, and nearby structures where the DBS electrode could be misplaced were also elucidated. The oblique planes could be understood concretely by comparing the volume model of the sectioned images with that of the segmented images. The real color and high resolution of the volume model enabled observations of minute structures even on the oblique planes. The volume models can be downloaded by users to be correlated with other patients’ data for grasping the anatomical orientation.

The sectioned images of a male’s whole body were used for making the four learning tools: the first tool to show the sectioned and color-filled images; the second tool to show surface models of individual structures; the third tool to show a volume model that was continuously peeled; the fourth tool to show a volume model that was freely sectioned. This study was intended to propose the possible learning effects of the four tools. The fourth tool that was recently developed to facilitate oblique sectioning and rotation of the volume model in real time. The four learning tools had their own characteristics, so that they could be separately used for specific achievements. Further, the combination of the tools based on the same raw data may result in a synergic effect. All the tools can be downloaded from the Visible Korean homepage (anatomy.co.kr) gratis. With the four learning tools, students may experience virtual dissection simulation regardless of the place, time, or economic status. Such free learning tools and commercial learning tools need to be improved to compensate and compete with each other.

Very recently, Task Group 103 of the International Commission on Radiological Protection (ICRP) completed the development of the pediatric Mesh-type Reference Computational Phantoms (MRCPs) comprising ten phantoms (newborn, 1-year-old, 5-year-old, 10-year-old, and 15-year-old males and females). The pediatric MRCPs address the limitations of ICRPPublication 143's pediatric reference computational phantoms, which are in voxel format, stemming from the nature of the voxel geometry and the limited voxel resolutions. The pediatric MRCPs were constructed by converting the voxel-type reference phantoms to a high-quality mesh format with substantial enhancements in the detailed anatomy of the small and complex organs and tissues (e.g., bones, lymphatic nodes, and extra-thoracic (ET) region). Besides, the pediatric MRCPs were developed in consideration of the intra-organ blood contents and by modelling the micron-thick target and source regions of the skin, lens, urinary bladder, alimentary tract organs, and respiratory tract organs prescribed by the ICRP. For external idealized exposures, the pediatric MRCPs provide very similar effective dose coefficients to those from the ICRP-143 phantoms but significantly different values for weakly penetrating radiations (e.g., the difference of ~20,000 times for 10-keV electron beams). This paper introduces the developed pediatric MRCPs with a brief explanation of the construction process. Then, it discusses their computational performance in Geant4, PHITS, and MCNP6 in terms of memory usage and computation speed and their impact on dose calculations by comparing their calculated values of effective dose coefficients for external exposures with those of the voxel-type reference phantoms.

For use in electron paramagnetic resonance dosimetry with tooth enamel, in the present study, very detailed mesh-type tooth models composed of 198 individual tooth models (i.e. newborn: 20; 1 year: 28; 5 years: 48; 10 years: 38; 15 years: 32; and adult: 32) were developed for each sex. The developed tooth models were then implanted in the International Commission on Radiological Protection pediatric and adult mesh-type reference computational phantoms and used to calculate tooth enamel doses, by Monte Carlo simulations with Geant4, for external photon exposures in several idealized irradiation geometries. The calculated dose values were then compared to investigate the dependency of the enamel dose on the age and sex of the phantom and the sites of the teeth. The results of the present study generally show that, if the photon energy is low (i.e.0.1 MeV), the enamel dose is significantly affected by the age and sex of the phantom and also the sites of the teeth used for dose calculation; the differences are frequently greater than a few times or even orders of magnitude. However, with a few exceptions, the enamel dose was hardly affected by these parameters for energies between 0.1 and 3 MeV. For energies3 MeV, moderate differences were observed (i.e., up to a factor of two), due to the existence of dose build-up in the head of the phantom for high-energy photons. The calculated dose values were also compared with those of the previous studies where voxel and mathematical models were used to calculate the enamel doses. The results again show significant differences at low energies, e.g., up to ∼3500 times at 0.015 MeV, which are mainly due to the differences in the level of tooth-modeling detailedness.

In order to differentiate normal sutures and pathological fractures on radiological images, age-specific anatomy of the sutures should be understood. For the detailed visualization of the skull, a cadaver’s sectioned images with real color and high resolution have been utilized. The sutures have been introduced using diverse imaging modalities including radiography, computed tomography, and magnetic resonance imaging. Clinical images of fracture were employed to elucidate the different aspects of the sutures and fractures. The sutures typically have sclerotic edge, consistent gap, zigzag pattern, and merging with other suture, while the fractures have non-sclerotic edge, inconsistent gap, straight pattern, intersecting with other suture, and scalp swelling.

It is difficult for medical students and novice clinicians to interpret cardiac computed tomographs and echocardiographs. This study was intended to help familiarize them with the clinical images of the heart by providing software to browse the various planes of a heart’s volume model with real color and high resolution. On the sectioned images of a male cadaver, the heart and adjacent structures were segmented to obtain color-filled images. Volume models of the sectioned images and color-filled images were reconstructed and sectioned to obtain three orthogonal planes and five standard oblique planes. The planes were inputted into lab-made browsing software, which was then distributed free of charge. Users of the software would hopefully progress as follows. After experiencing the real color and high resolution, they would become familiar with the grayscale and low resolution. After experiencing the automatic annotation of the basic heart structures, they would become familiar with the detailed structures. After experiencing the designated planes, they would become familiar with the arbitrary planes. After experiencing the still heart, they would become familiar with the moving heart during echocardiography. The software, with a user-friendly interface and realistic features, is expected to properly orient medical novices to cardiac computed tomography and echocardiography images.

Background A book entitled “Visually Memorable Regional Anatomy (VMRA)” consists of extremely schematic figures as well as concise anatomic knowledge. On the other hand, in the Visible Korean (VK) project, three-dimensional surface models of 297 head structures have been reconstructed. The study's objective was to verify how the coexistence of the schematic figures and realistic surface models affected anatomy learning. Methods In the portable document format (PDF) file of VMRA, 19 pages of the surface models of the head from the PDF file of VK were embedded. The resultant PDF file was utilized as a learning tool of the medical students in two universities. Results The PDF file could be downloaded free of charge from anatomy.co.kr. The PDF file has been accessed by users from multiple countries including Korea, United States, and Hungary. In the PDF file, the surface models could be selected in any combinations, magnified, freely rotated, and compared to the corresponding schematics. The number of hours that the PDF file was used by medical students and the scores of written examination on the PDF file showed a low positive correlation in a university. The students replied that the combined PDF file was helpful for understanding anatomy and for doing cadaver dissection. They were also satisfied with the convenience of comparing the surface models and schematics. Conclusion The freely obtainable PDF file would be a beneficial tool to help students learn anatomy easily, interactively, and accurately., Graphical Abstract

Background To help medical students learn anatomy effectively in limited hours, a regional anatomy book enhancing students' memorization was developed. Methods Only anatomical terms essential for basic cadaver dissection are included along with schematic figures which enable memorization of complicated anatomical structures. Learning comics and comic strips that depict anatomy mnemonics and jokes were appended and sentences were written to be comfortably readable. The electronic book titled “Visually Memorable Regional Anatomy” has been distributed without payment or registration. With the help of 246 volunteer students from three Korean medical schools, the book's learning effects were evaluated. Results These students' book reading led to increase in their anatomy scores, including written examination scores and tag examination scores. It was an encouraging result that almost 20% of students spontaneously read the book no matter who presented their lecture or examination. A webpage version of the book was visited by thousands of users. Conclusion The book with unique features may suggest a new perspective in the field of anatomy learning. After having acquaintance with essential structures from reading the book, students are able to and willing to study more from other resources., Graphical Abstract

This chapter explores the comprehensive functions of the brain, which are closely related not only to the morphology of the brain but also to the somatic and autonomic nerves of the cranial and spinal nerves. Details are the functions of the cerebral cortex, limbic system, basal nuclei, diencephalon, cerebellum, and brainstem. Readers can see drawings with consistent style of the brain shape and the neuronal connections. This chapter often refers to the general rule of afferent nerves having three neurons that is developed by the authors. The functions of the brain are explained within the boundary of neuroanatomy; the rest of the functions fall under neurophysiology.

Background Recently, new concepts about obesity and normal weight subtypes with metabolic conditions are rising and ketone bodies are emerging as a significant indicator of metabolic health. This study aimed to find a relationship between ketonuria and those subtypes. Methods The data of 19,036 subjects were analyzed in this cross-sectional study (2013–2017 Korea National Health and Nutrition Examination Survey, KNHANES). Based on body mass index and adult treatment panel III with modification of waist circumference, individuals were categorized into 4 groups: metabolically healthy normal weight (MHNW), metabolically healthy obese (MHO), metabolically unhealthy normal weight (MUNW), and metabolically unhealthy obese (MUO). Individuals were divided into 2 groups, positive and negative ketonuria groups, and the metabolic parameters were compared. Results The metabolic indicators of the positive ketonuria group showed better results than those of the negative ketonuria group and the MHNW group showed the highest proportion of positive ketonuria. The MHNW group showed higher urinary ketones than the MUO group (odds ratio [OR], 0.391; 95% confidence interval [CI], 0.254–0.601) in men. In women, OR of having ketonuria was 0.698 (95% CI, 0.486–1.002) in the MHO group and 0.467 (95% CI, 0.226–0.966) in the MUNW group compared to the MHNW group, respectively. Conclusion Compared to the MHNW group, the MUO group showed lower presence of ketonuria in men, and tendency to have less ketonuria in women., Graphical Abstract

The nervous system consists of four kinds of nerves: the somatic sensory nerve from receptor around the skeletal muscle (e.g., receptor in the skin), the somatic motor nerve to the skeletal muscle (voluntary muscle), the visceral sensory nerve from the receptor around the smooth or cardiac muscle (e.g., receptor in the gastrointestinal tract), and the visceral motor nerve (autonomic nerve) to the smooth or cardiac muscle (involuntary muscle). This chapter explores two pathways of the somatic sensory nerve (spinothalamic tract and medial lemniscus pathway), one pathway of the somatic motor nerve (corticospinal tract). Additional content is two components of the visceral motor nerve (sympathetic and parasympathetic nerves). Comprehension of the pathways is enhanced by practice with stained slices of the brainstem and spinal cord (or their photos).

For performing lateral transpsoas approaches to the lumbar spine, the anatomy of the region should be well understood, and conventional cadaveric dissection is still considered the best method for viewing this anatomy. However, sectional anatomy of the region is necessary for a more concrete understanding of the spatial relationship. After grasping the sectional anatomy, surgeons can avoid possible iatrogenic injuries and interpret magnetic resonance images and computed tomography images more accurately.