Beom Sun Chung

Incorporation of detailed eye model into polygon-mesh versions of ICRP-110 reference phantoms.

The dose coefficients for the eye lens reported in ICRP 2010 Publication 116 were calculated using both a stylized model and the ICRP-110 reference phantoms, according to the type of radiation, energy, and irradiation geometry. To maintain consistency of lens dose assessment, in the present study we incorporated the ICRP-116 detailed eye model into the converted polygon-mesh (PM) version of the ICRP-110 reference phantoms. After the incorporation, the dose coefficients for the eye lens were calculated and compared with those of the ICRP-116 data. The results showed generally a good agreement between the newly calculated lens dose coefficients and the values of ICRP 2010 Publication 116. Significant differences were found for some irradiation cases due mainly to the use of different types of phantoms. Considering that the PM version of the ICRP-110 reference phantoms preserve the original topology of the ICRP-110 reference phantoms, it is believed that the PM version phantoms, along with the detailed eye model, provide more reliable and consistent dose coefficients for the eye lens.

New small-intestine modeling method for surface-based computational human phantoms

When converting voxel phantoms to a surface format, the small intestine (SI), which is usually not accurately represented in a voxel phantom due to its complex and irregular shape on one hand and the limited voxel resolutions on the other, cannot be directly converted to a high-quality surface model. Currently, stylized pipe models are used instead, but they are strongly influenced by developers subjectivity, resulting in unacceptable geometric and dosimetric inconsistencies. In this paper, we propose a new method for the construction of SI models based on the Monte Carlo approach. In the present study, the proposed method was tested by constructing the SI model for the polygon-mesh version of the ICRP reference male phantom currently under development. We believe that the new SI model is anatomically more realistic than the stylized SI models. Furthermore, our simulation results show that the new SI model, for both external and internal photon exposures, leads to dose values that are more similar to those of the original ICRP male voxel phantom than does the previously constructed stylized SI model.

Inclusion of thin target and source regions in alimentary and respiratory tract systems of mesh-type ICRP adult reference phantoms

It is not feasible to define very small or complex organs and tissues in the current voxel-type adult reference computational phantoms of the International Commission on Radiological Protection (ICRP), which limit dose coefficients for weakly penetrating radiations. To address the problem, the ICRP is converting the voxel-type reference phantoms into mesh-type phantoms. In the present study, as a part of the conversion project, the micrometer-thick target and source regions in the alimentary and respiratory tract systems as described in ICRP Publications 100 and 66 were included in the mesh-type ICRP reference adult male and female phantoms. In addition, realistic lung airway models were simulated to represent the bronchial (BB) and bronchiolar (bb) regions. The electron specific absorbed fraction (SAF) values for the alimentary and respiratory tract systems were then calculated and compared with the values calculated with the stylized models of ICRP Publications 100 and 66. The comparisons show generally good agreement for the oral cavity, oesophagus, and BB, whereas for the stomach, small intestine, large intestine, extrathoracic region, and bb, there are some differences (e.g. up to ~9 times in the large intestine). The difference is mainly due to anatomical difference in these organs between the realistic mesh-type phantoms and the simplified stylized models. The new alimentary and respiratory tract models in the mesh-type ICRP reference phantoms preserve the topology and dimensions of the voxel-type ICRP phantoms and provide more reliable SAF values than the simplified models adopted in previous ICRP Publications.

Development of skeletal system for mesh-type ICRP reference adult phantoms

The reference adult computational phantoms of the international commission on radiological protection (ICRP) described in Publication 110 are voxel-type computational phantoms based on whole-body computed tomography (CT) images of adult male and female patients. The voxel resolutions of these phantoms are in the order of a few millimeters and smaller tissues such as the eye lens, the skin, and the walls of some organs cannot be properly defined in the phantoms, resulting in limitations in dose coefficient calculations for weakly penetrating radiations. In order to address the limitations of the ICRP-110 phantoms, an ICRP Task Group has been recently formulated and the voxel phantoms are now being converted to a high-quality mesh format. As a part of the conversion project, in the present study, the skeleton models, one of the most important and complex organs of the body, were constructed. The constructed skeleton models were then tested by calculating red bone marrow (RBM) and endosteum dose coefficients (DCs) for broad parallel beams of photons and electrons and comparing the calculated values with those of the original ICRP-110 phantoms. The results show that for the photon exposures, there is a generally good agreement in the DCs between the mesh-type phantoms and the original voxel-type ICRP-110 phantoms; that is, the dose discrepancies were less than 7% in all cases except for the 0.03 MeV cases, for which the maximum difference was 14%. On the other hand, for the electron exposures (⩽4 MeV), the DCs of the mesh-type phantoms deviate from those of the ICRP-110 phantoms by up to ~1600 times at 0.03 MeV, which is indeed due to the improvement of the skeletal anatomy of the developed skeleton mesh models.

Virtual Dissection Table Including the Visible Korean Images, Complemented by Free Software of the Same Data

El objetivo de este estudio fue introducir la relacion complementaria entre una mesa virtual de diseccion (simplemente, la mesa) y un programa de libre acceso. Mediante este proceso los autores trataron de ayudar a aquellas personas interesadas en el estudio de la anatomia humana digital. El equipo Visible Korean (VK) habia presentado las imagenes de secciones consecutivas e imagenes de un cadaver de sexo masculino. Partiendo de ese punto, la compania Anatomage fabrico la mesa produciendo con los datos modelos dimensionales de volumen (3D). En forma paralela, el equipo VK reconstruyo los modelos de superficie con los mismos datos y de entrada de los modelos en formato de documento portatil (PDF), que se pudieran abrir en el ordenador personal. El equipo VK ademas lo programo para navegar a traves de las imagenes seccionadas y descritas. En este informe, la mesa y el programa VK fueron comparados para establecer su potencialidad complementaria. Tanto la mesa como el programa de libre acceso muestran modelos 3D equivalentes reconstruidos a partir de las mismas imagenes seccionadas. En ambas plataformas, se marcaron los modelos para que los usuarios reconozcan las estructuras individuales. Tanto la mesa y el programa libre tenian caracteristicas respectivas para mejorar la experiencia de diseccion virtual. La mesa incluia el hardware designado con la pantalla de tamano natural, mientras que el programa VK podia ser ejecutado en cualquier ordenador personal sin dificultad alguna. La coexistencia de la mesa y el programa libre pueden ser un apoyo importante para quienes estudien anatomia. Con el aumento de los datos de VK y el programa libre, se espera que exista una mayor cantidad de productos comerciales o gratuitos.

Surface models and gradually peeled volume model to explore hand structures

This study was intended to confirm whether simultaneous examination of surface and volume models contributes to learning of hand structures. Outlines of the skin, muscles, and bones of the right hand were traced in sectioned images of a male cadaver to create surface models of the structures. After the outlines were filled with selected colors, the color-filled sectioned images were stacked to produce a volume model of the hand, from which the skin was gradually peeled. The surface models provided locational orientation of the hand structures such as extrinsic and intrinsic hand muscles, while the peeled volume model revealed the depth of the individual hand structures. In addition, the characteristic appearances of the radial artery and the wrist joint were confirmed. The exploration of the volume model accompanied by equivalent surface models is synergistically helpful for understanding the morphological properties of hand structures.

Peeled and Piled Volume Models of the Stomach Made from a Cadaver's Sectioned Images

El diagnostico y el tratamiento de enfermedades del estomago requieren del conocimiento del mayor numero de detalles posible sobre su anatomia. El objetivo de este estudio, basado en secciones de imagenes de cadaver, es ofrecer a los medicos la anatomia del estomago y sus estructuras vecinas desde un nuevo punto de vista. Se utilizaron imagenes de secciones de un cadaver, de sexo masculino, sin patologia del estomago. Por segmentacion manual y automatica de interpolacion, se reconstruyo un modelo de volumen de alta calidad del estomago. El modelo fue descortezado y apilado para revelar sinteticamente el interior y exterior del estomago. Se compararon los puntos de vista anterior, posterior, derecho e izquierdo de los modelos en una seccion elegida. Las numerosas imagenes del estomago luego fueron puestas en el software de navegacion de facil uso para el profesional. Algunas de las ventajas de este estudio son que las imagenes seccionadas revelan el color real del estomago con alta resolucion; los modelos de volumen descortezados y apilados dan lugar a nuevas funciones del estomago y sus estructuras circundantes; y los modelos procesados pueden ser convenientemente navegados en el software presentado. Se espera que estos datos de imagen y el tutorial del programa sean de utilidad para la adquisicion de informacion morfologica complementaria sobre el estomago y las estructuras relacionadas.

Colonoscopy tutorial software made with a cadaver's sectioned images.

Novice doctors may watch tutorial videos in training for actual or computed tomographic (CT) colonoscopy. The conventional learning videos can be complemented by virtual colonoscopy software made with a cadavers sectioned images (SIs). The objective of this study was to assist colonoscopy trainees with the new interactive software. Submucosal segmentation on the SIs was carried out through the whole length of the large intestine. With the SIs and segmented images, a three dimensional model was reconstructed. Six-hundred seventy-one proximal colonoscopic views (conventional views) and corresponding distal colonoscopic views (simulating the retroflexion of a colonoscope) were produced. Not only navigation views showing the current location of the colonoscope tip and its course, but also, supplementary description views were elaborated. The four corresponding views were put into convenient browsing software to be downloaded free from the homepage (anatomy.co.kr). The SI colonoscopy software with the realistic images and supportive tools was available to anybody. Users could readily notice the position and direction of the virtual colonoscope tip and recognize meaningful structures in colonoscopic views. The software is expected to be an auxiliary learning tool to improve technique and related knowledge in actual and CT colonoscopies. Hopefully, the software will be updated using raw images from the Visible Korean project.

Six Walls of the Cavernous Sinus Identified by Sectioned Images and Three-Dimensional Models: Anatomic Report

BACKGROUND For the diagnosis and surgical treatment of diseases around the cavernous sinus (CS), radiologists should achieve complete mastery of the sectional anatomy of the CS, and neurosurgeons need to understand the stereoscopic orientation of the CS and circumjacent structures. However, despite the complicated structure of the CS, the current educational resources for its sectional and stereoscopic anatomy are insufficient. Another problem is that the definition of CS walls varies for each researcher. The purpose of this study is to redefine the walls of the CS and to provide related educational materials. METHODS Previous studies on the shape of the CS were analyzed. Sectioned images of a cadaver were prepared at 0.1-mm intervals to be made into three-dimensional (3D) models of the CS and neighboring structures. RESULTS Based on other studies, the shape of the CS was redefined as a hexahedron, consisting of 6 walls, and was illustrated as a schematic figure. Scientific exactitude of the hexahedron was proven through matching the points with the actual structures on the sectioned images and 3D models that were made in this study. CONCLUSIONS The combination of the hexahedron theory, the sectioned images, and the 3D models in this study will enhance the efficiency of studying CS anatomy. The educational resources of this study can be obtained free of charge by medical students, radiologists, and neurosurgeons requiring knowledge of CS anatomy.

Software to Browse the Pictures of Two Knees in Diverse States of Dissection, Flexion and Rotation

El objetivo de este estudio fue producir imagenes de las rodillas de un cadaver embalsamado y otro de cadaver fresco, con diversos niveles de diseccion, flexion y rotacion, con el fin de ayudar a los estudiantes de medicina y a los medicos, en el estudio de la anatomia de la rodilla. En este estudio, la intencion fue mejorar la accesibilidad de las numerosas fotografias de la rodilla, mediante la introduccion de estas, producidas en nuestro propio programa de navegacion. El programa se puede descargar de forma gratuita desde la pagina web (anatomy.co.kr). En el programa, una matriz que constaba de cuatro fotografias: una rodilla a tres profundidades diferentes de diseccion y la misma rodilla en el estado flexionado. La rodilla podia girar de forma interactiva en cada angulo de 5°. Anotacion de las estructuras importantes de la rodilla podian ser vistas a intervalos de 90° de angulo. Con el software de navegacion, los usuarios pudieron observar caracteristicas detalladas y realistas de las rodillas flexionadas y disecadas. Ademas, la comparacion de las rodillas embalsamadas y frescas mejora la comprension de la apariencia real de la rodilla. Los datos del programa y de imagen extraible se pueden utilizar como materiales de educacion en anatomia para diversos fines.