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

Tissue clearing technology is currently one of the fastest growing fields in biomedical sciences. Tissue clearing techniques have become a powerful approach to understand further the structural information of intact biological tissues. Moreover, technological improvements in tissue clearing and optics allowed the visualization of neural network in the whole brain tissue with subcellular resolution. Here, we described an overview of various tissue-clearing techniques, with focus on the tissue-hydrogel mediated clearing methods, and discussed the main advantages and limitations of transparent tissue for clinical diagnosis.
Brain ; Diagnosis ; Imaging, Three-Dimensional ; Neurosciences

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*

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

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

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.

The positioning error in radiotherapy is one of the most important factors that influence the location precision of the tumor. Based on the CT-on-rails technology, this paper describes the research on measuring the positioning error in radiotherapy by comparing the planning CT images with the treatment CT images using 3-dimension (3D) methods. It can help doctors to measure positioning errors more accurately than 2D methods. It also supports the powerful 3D interaction such as drag-dropping, rotating and picking-up the object, so that doctors can visualize and measure the positioning errors intuitively.
Humans ; Imaging, Three-Dimensional ; Radiotherapy ; methods

OBJECTIVETo evaluate the clinical application effect of a three-dimensional craniomaxillofacial measurement instrument.

METHODSA three-dimensional craniomaxillofacial measurement instrument was developed. Twelve patients of unilateral fracture of zygoma complex were treated with the help of the three-dimensional craniomaxillofacial measurement instrument.

RESULTSThe therapeutic effects of twelve patients were satisfactory with the three-dimensional craniomaxillofacial measurement instrument. No complication occurred, such as infection, injury of nerves and veins.

CONCLUSIONThree-dimensional craniomaxillofacial measurement instrument can exactly measure craniomaxillofacial hard tissue, and has adjuvant effect to restore and fix the fracture of unilateral zygoma complex.