A Compton camera, which is based on the geometrical interpretation of Compton scattering, is a very promising gamma-ray imaging device considering its several advantages over the conventional gamma-ray imaging devices: high imaging sensitivity, 3-D imaging capability from a fixed position, multi-tracing functionality, and almost no limitation in photon energy. In the present study, a Monte Carlo-based, user-friendly Compton imaging simulator was developed in the form of a graphical user interface (GUI) based on Geant4 and MATLAB (TM). The simulator was tested against the experimental result of the double-scattering Compton camera, which is under development at Hanyang University in Korea. The imaging resolution of the simulated Compton image well agreed with that of the measured image. The imaging sensitivity of the measured data was 2~3 times higher than that of the simulated data, which is due to the fact that the measured data contains the random coincidence events. The performance of a stacking-structure type Compton camera was evaluated by using the simulator. The result shows that the Compton camera shows its highest performance when it uses 4 layers of scatterer detectors.
Imaging, Three-Dimensional ; Korea

No abstract available.
Erythrocytes ; Imaging, Three-Dimensional ; Microscopy

The lack of depth perception and spatial orientation in two-dimensional image of traditional laparoscopy require long-term training of the surgeons. Three-dimensional (3D) laparoscopy provides stereoscopic visions as compared to monocular views in a traditional laparoscopic system. In this review, the authors summarize the clinical application of 3D laparoscopy and its current research progress.
Imaging, Three-Dimensional ; instrumentation ; methods ; Laparoscopy ; methods

OBJECTIVE: After drawing and stacking contour of structures, which are identifed in the serially sectioned images, three-dimensional (3D) images can be made by surface reconstruction. The 3D images can be selected and rotated in a real time. The purpose of this research is to compose software of automatic surface reconstruction for making 3D images. METHODS: Contours of 55 structures in the 613 magnetic resonance images of whole body were drawn to make segmented images. We composed automatic software for stacking contours of a structure, for converting the contours into polygons, and for connecting vertices of the neighboring polygons to fill gaps between polygons with triangular surfaces. The surface reconstruction software was excuted to make 3D images of 55 structures. RESULTS: Virtual dissection software, on which 3D images could be selected and rotated, was composed. CONCLUSION: For other research, this like program can be composed for automatic surface reconstruction; several kinds of commercial software can be used for manual or automatic surface reconstruction. Investigators might choose one of the methods in consideration of their only circumstances.
Humans ; Imaging, Three-Dimensional ; Research Personnel

It is difficult to measure the circular arc radius for central angle less than 30 degrees. The existing measuring methods are of low efficiency and big error. Through designing the machine vision system and studying the image detecting method for measurement, It is obtained good results by using the new measurement for tracheal intubation's circular arc radius, Realized a rapid and accurate measurement of the circular arc radius, and expanded the application in the field of machine vision.
Humans ; Imaging, Three-Dimensional ; instrumentation ; Intubation ; Trachea

OBJECTIVEThis work lays the foundation for establishing a digital model database with normal occlusion. A digital dental cast is acquired through grating projection, and model features are measured through reverse engineering.

METHODSThe grating projection system controlled by a computer was projected onto the surface of a normal dental model. Three-dimensional contour data were obtained through multi-angle shooting. A three-dimensional model was constructed, and the model features were analyzed by using reverse engineering. The digital model was compared with the plaster model to determine the accuracy of the measurement system.

RESULTSThe structure of three-dimensional reconstruction model was clear. The digital models of two measurements exhibited no significant difference (P > 0.05). When digital and plaster models were measured, we found that the crown length and arch width were not statistically different (P > 0.05), whereas the difference between the crown width and arch length was statistically significant (P < 0.05).

CONCLUSIONThe reconstruction of a digital model by using the grating projection technique and reverse engineering can be used for dental model measurement in clinic al and scientific research and can provide a scientific method for establishing a digital model database with normal occlusion.

Small bowel obstruction is a relatively common clinical condition and its diagnosis is based on the clinical signs, the patient's history and the radiologic findings. For a patient with suspected small bowel obstruction, it is essential to determine the site, location and cause of obstruction for the appropriate management. Because of the poor accuracy of plain radiography, computed tomography (CT) now has an essential role to diagnose bowel obstruction. With the recent evolution of conventional CT into multi-detector computed tomography (MDCT), it is possible to obtain cross sectional images with high spatial resolution and different post-processes can be done, such as obtaining the volume rendering (VR), maximum intensity projection (MIP), or multiplanar reformatted (MPR) images from the volume data. In this article, we illustrate and discuss the utility of the multiplanar images of MDCT for diagnosing the sites, causes and complications of small bowel obstruction.
Humans ; Imaging, Three-Dimensional ; Multidetector Computed Tomography

OBJECTIVE: The purpose of this study was to compare the precision of three-dimensional (3D) images acquired using iTero(R) (Align Technology Inc., San Jose, CA, USA) and Trios(R) (3Shape Dental Systems, Copenhagen, Denmark) digital intraoral scanners, and to evaluate the effects of the severity of tooth irregularities and scanning sequence on precision. METHODS: Dental arch models were fabricated with differing degrees of tooth irregularity and divided into 2 groups based on scanning sequence. To assess their precision, images were superimposed and an optimized superimposition algorithm was employed to measure any 3D deviation. The t-test, paired t-test, and one-way ANOVA were performed (p < 0.05) for statistical analysis. RESULTS: The iTero(R) and Trios(R) systems showed no statistically significant difference in precision among models with differing degrees of tooth irregularity. However, there were statistically significant differences in the precision of the 2 scanners when the starting points of scanning were different. The iTero(R) scanner (mean deviation, 29.84 +/- 12.08 microm) proved to be less precise than the Trios(R) scanner (22.17 +/- 4.47 microm). CONCLUSIONS: The precision of 3D images differed according to the degree of tooth irregularity, scanning sequence, and scanner type. However, from a clinical standpoint, both scanners were highly accurate regardless of the degree of tooth irregularity.
Dental Arch ; Imaging, Three-Dimensional* ; Tooth*

It is possible to compare three-dimensional image of patterned injury in virtual space with object using 3D/CAD supported photogrammetry(FPHG). this method make it possible to examine patterned injuries of skin, soft tissue and bone for matching instruments in shape, size and angle without altering. Generally, 3D measuring of objects require 3D digitizer or series of photographs taking by metric camera. We developed program which calibrate pictures taken by non-calibrated commercial camera and un distorted image. This image and objet model n can be examined with respect to matching shapes using 3D/CAD system.
Imaging, Three-Dimensional ; Photogrammetry ; Skin ; United Nations

OBJECTIVE: Watershed algorithm is image segmentation algorithm divides the image into numerous small regions. This paper proposes a new approach to extract the lung region from the three dimensional color image of Frozen Human Body (Visible Human Male) based on watershed algorithm. METHODS: After applying this algorithm to input image and getting the small regions, we merge these small regions into one region with three measures based on color, edge marker, and SURFACE respectively. RESULTS: We can say that the smaller number of FALSE-POSITIVE and TRUE NEGATIVE voxels and the larger number of FALSE POSITIVE voxels are better result. Graph shows change in the number of voxel in above groups of the left lung detection when tau color change with tau em is 0.7. We think that the result at the range of tau color from 110 to 180 are better than the other results in Graph. CONCLUSION: Comparing with our previous work, we newly use Canny edge filter for edge marker and define SURFACE-based dissimilarity to relax the problem of its step. The users must select a point within the lung region and some thresholds (taucolor, tauem, tauhigh, taulow, delta) to detect the target region.
Human Body ; Humans* ; Imaging, Three-Dimensional ; Lung*