• Journal of Life Science
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• v.20 no.8
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• pp.1207-1213
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• 2010

The purpose of this study was to evaluate the effect of porcine cancellous bone as a scaffold in a rat calvarial defect model. Critical-sized defects were created in 30 male Sprague-Dawley rats. The animals were divided into critical defect (CD, n=10), $\beta$-tricalcium phosphate (TCP) graft (BT, n=10) and porcine cancellous bone graft (PCB, n=10) groups. Each defect was filled with $\beta$-TCP mixed with fibrin glue or porcine cancellous bone powder mixed with fibrin glue. In the CD group, the defect was left empty. All rats were sacrificed at 8 weeks after bone graft surgery, and bone formation was evaluated by gross observation, plain radiography, micro-computed tomography scanning and histological evaluation. Repair of bone defect was the least in the CD group, and significant new bone formation was observed in the PCB group. Grafting of porcine cancellous bone was more efficient for regenerating new bone than grafting $\beta$-TCP.

• Investigative Magnetic Resonance Imaging
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• v.12 no.2
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• pp.170-177
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• 2008

Purpose : To evaluate usefulness of MR imaging after serial brain US in the high-risk neonates before discharge of the neonatal intensive care unit. Materials and Methods : Retrospective comparison of 412 US and 121 MR scans in 121 neonates and young infants were performed. Grading of germinal matrix/intraventricular hemorrhage (GMH/IVH) was performed and presence of intracranial hemorrhage other than GMH/IVH and parencyma lesions was also analyzed. Results : Among the 242 lateral ventricles, Seven GMH and 46 IVH were additionally detected by MRI. On the other hand, 30 GMH were only detected by US. US demonstrated Grade 1/2/3/4 GMH/IVH in 24/8/13/0 ventricles each, while each grades were identified in 3, 49, 10, 2 ventricles on MR images. Other intracranial lesions additionally detected on MR images were cerebral hemorrhage (n=4), cerebellar hemorrhage (n=4), extraaxial hemorrhage (n=8), diffuse excessive signal change of the white matter (n=72), non-cavitary lesion (n=4), encephalomalacia (n=2), and ventriculomegaly (n=5). Conclusion : MR imaging could be an excellent complimentary study after serial brain US for additional detection of the intracranial pathology, particularly IVH and white matter lesions, though US would be better in follow-up of GMH in some neonates.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.2
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• pp.83-87
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• 2008

Diagnostic and functional imaging device have been developed independently. The recognition that combining of these two devices can provide better diagnostic outcomes by fusing anatomical and functional images. The representative examples of combining devices would be PET/CT and SPECT/CT. Development and their applications of animal imaging and instrumentation have been very active, as new drug development with advanced imaging device has been increased. The development of advanced imaging device resulted in researching and developing for detector technology and imaging systems. It also contributed to develop a new software, reconstruction algorithm, correction methods for physical factors, image quantitation, computer simulation, kinetic modeling, dosimetry, and correction for motion artifacts. Recently, development of MRI and PET by combining them together was reported. True integration of MRI and PET has been making the progress and their results were reported. The recent status of imaging and instrumentation in nuclear medicine is reported in this paper.

• Radiation Oncology Journal
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• v.7 no.1
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• pp.93-100
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• 1989

Several combinations of measuring devices and phantoms were studied to measure electron beams. Silicon Pmt junction diode was used to find the dependence of depth dose profile on field size on axis of electron beam Depths of 50, 80 and $90\%$ doses increased with the field size for small fields. For some larger fields, they were nearly constant. The smallest of field sizes over which the parameters were constant was enlarged with increase of the energy of electron beams. Depth dose distributions on axis of electron beam of $10\times10cm^2$ field were studied with several combinations of measuring devices and phantoms. Cylindrical ion chamber could not be used for measurement of surface dose, and was not convenient for measurement of near surface region of 6MeV electron. With some exceptions, parameters agreed well with those studied by different devices and phantoms. Surface dose in some energies showed $4\%$ difference between maximum and minimum. For 18MeV, depths of 80 and $90\%$ doses were considerably shallower by film than by others. Parallel-plate ion chamber with polystyrene phamtom and silicon PN junction would be recommended for measurement of central axis depth dose of electron beams with considerably large field size. It is desirable not to use cylindrical ion chamber for the purpose of measurement of surface dose or near surface region for lower energy electron beam. It is questionable that film would be recommended for measurement of dose distribution of electron with high energy like as 18MeV.

• Progress in Medical Physics
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• v.26 no.1
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• pp.18-27
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• 2015

Since a Compton camera has high detection sensitivity due to electronic collimation and a good energy resolution, it is a potential imaging system for nuclear medicine. In this study, we investigated the feasibility of a Compton camera for multi-tracer imaging and proposed a rotating Compton camera to satisfy Orlov's condition for 3D imaging. Two software phantoms of 140 and 511 keV radiation sources were used for Monte-Carlo simulation and then the simulation data were reconstructed by listmode ordered subset expectation maximization to evaluate the capability of multi-tracer imaging in a Compton camera. And the Compton camera rotating around the object was proposed and tested with different rotation angle steps for improving the limited coverage of the fixed conventional Compton camera over the field-of-view in terms of histogram of angles in spherical coordinates. The simulation data showed the separate 140 and 511 keV images from simultaneous multi-tracer detection in both 2D and 3D imaging and the number of valid projection lines on the conical surfaces was inversely proportional to the decrease of rotation angle. Considering computation load and proper number of projection lines on the conical surface, the rotation angle of 30 degree was sufficient for 3D imaging of the Compton camera in terms of 26 min of computation time and 5 million of detected event number and the increased detection time can be solved with multiple Compton camera system. The Compton camera proposed in this study can be effective system for multi-tracer imaging and is a potential system for development of various disease diagnosis and therapy approaches.

• Investigative Magnetic Resonance Imaging
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• v.11 no.1
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• pp.10-19
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• 2007

Conventional MRI methods using T1-, T2-, diffusion-, perfusion-weighting, and functional imaging rely on characterizing the physical and functional properties of the tissue. In this review, we introduce an imaging modality based on measured the mechanical properties of soft tissue, namely magnetic resonance elastography (MRE). The use of palpation to identify the stiffness of tissue remains a fundamental diagnostic tool. MRE can quantify the stiffness of the tissue thereby providing a objective means to measure the mechanical properties. To accomplish a successful clinical setting using MRE, hardware and software techniques in the area of transducer, pulse sequence, and imaging processing algorithm need to be developed. Transducer, a mechanical vibrator, is the core of MRE application to make wave propagate invivo. For this reason, considerations of the frame of human body, pressure and friction of the interface, and high magnetic field of a MRI system needs to be taken into account when designing a transducer. Given that the wave propagates through human body effectively, developing an appropriate pulse sequence is another important issue in obtaining an optimal image. In this review paper, we introduce the technical aspects needed for MRE experiments and introduce several applications of this new field.

• Investigative Magnetic Resonance Imaging
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• v.14 no.1
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• pp.10-20
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• 2010

Purpose : Recently, the Recon Challenge at the 2009 ISMRM workshop on Data Sampling and Image Reconstruction at Sedona, Arizona was held to evaluate feasibility of highly accelerated acquisition of time resolved contrast enhanced MR angiography. This paper provides the step-by-step description of the winning results of k-t FOCUSS in this competition. Materials and Methods : In previous works, we proved that k-t FOCUSS algorithm successfully solves the compressed sensing problem even for less sparse cardiac cine applications. Therefore, using k-t FOCUSS, very accurate time resolved contrast enhanced MR angiography can be reconstructed. Accelerated radial trajectory data were synthetized from X-ray cerebral angiography images and provided by the organizing committee, and radiologists double blindly evaluated each reconstruction result with respect to the ground-truth data. Results : The reconstructed results at various acceleration factors demonstrate that each components of compressed sensing, such as sparsifying transform and incoherent sampling patterns, etc can have profound effects on the final reconstruction results. Conclusion : From reconstructed results, we see that the compressed sensing dynamic MR imaging algorithm, k-t FOCUSS enables high resolution time resolved contrast enhanced MR angiography.

• Journal of radiological science and technology
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• v.29 no.4
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• pp.261-265
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• 2006

This study designed for identifying whether female and the thin and the light have gastroptosis more, as known from long time ago, or not, through analyzing correlation of gastroptosis and degree of obesity. People who are subject of health examination for adult disease, who visited a health examination hospital at downtown in pusan, and then are received health examination, who are conducted UGI series between January and June in 2006 are eligible for the study. During the same period, randomised 584 people without gastroptosis were enrolled, grouped with sex and age, and each group involved 73 people. The classification of figure of body was based on standard weight table, and Broca's fomular was used for calculation of degree of obesity. and then We get the result, as following, 1. The women(514/584) have gastroptosis more than men(70/584). 2. Gastroptosis is most common in 90-109%, 54.3% of male, 56.4% of female. The man 90% under, the woman appeared with 110-119%. 3. In the distribution of degree of obesity between ages, gastroptosis is more common at the fifties, and there is no sexual difference.

• Journal of radiological science and technology
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• v.40 no.3
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• pp.433-441
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• 2017

The 3D printing selective laser sintering (SLS) and stereo lithography apparatus (SLA) method used for bone model production has good precision and resolution, but the printers are expensive and need professional knowledge for operation. The program that converts computed tomography digital imaging and communications in medicine (DICOM) file into STL (stereolithography) file is also expensive so requesting 3D printing companies takes a lot of time and cost, which is why they are not generally utilized in surgery. To produce bone models of fractured patients, the use of 3D imaging conversion program and 3D printing system should be convenient, and the cost of device and operation should be low. Besides, they should be able to produce big size bone models for application to surgery. Therefore, by using an fused deposition modeling (FDM) method 3D printer that uses thermoplastic materials such as DICOM Viewer OsiriX and plastic wires, this study developed 3D printing system for Fracture surgery Patients customized bone model production for many clinics to use for surgery of fracture patients by universalizing with no limit in printing sizes and low maintenance and production cost. It is expected to be widely applied to the overall areas of orthopedics' education, research and clinic. It is also expected to be conveniently used in not only university hospitals but also regular general hospitals.

• Radiation Oncology Journal
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• v.14 no.4
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• pp.255-264
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• 1996

Purpose : Paclitaxel is a chemotherapeutic agent with potent microtubule stabilizing activity that arrests cell cycle in $G_2$-M Because $G_2$-M is the most radiosensitive Phase of the cell cycle, paclitaxel has potential as a cell cycle- specific radiosensitizer. This study was designed to investigate the ability of paclitaxel to increase the radiotoxicity in normal small bowel mucosa of the rat. materials and Methods : A sigle intraperitoneal infusion of paclitaxel (10mg/kg), and a single irradiation(8 Gy, x-ray) to the whole abdomen and combination of radiation(8 Gr, x-ray) 24 hours after paclitaxel infusion in the rats were done. The changes of jejunal mucosa, and kinetics of mitotic arrest and apoptosis in the jejunal crypt were defined at 6 hours - 5 days after each treatment histologically. Results : Paclitaxel blocked jejunal crypt cell in mitosis and induced minmal apoptosis. Mitotic arrest by paclitaxel was peaked at 6 hours after infusion and returned to normal by 24 hours. Radiation induced apoptosis and peaked at 6 hours and returned to normal by 24 hours. Combination of paclitaxel and radiation blocked crypt cell in mitosis at 3 days and induced apoptosis slightly at 6 hours and 24 hours and returned to normal by 3 days. The incidence of apoptosis in combined group at 6 hours was slightly higher than normal control but significantly lower than radiation alone group. The major changes of jejunal mucosa were nuclear vesicle and atypia which were appeared at 6 hours - 3 days and returned to normal by 5 days The degree of the mucosal changes are not different in 3 groups except for absence of inflmmatory reaction in radiation group. Conclusion : Mitotic arrest by paclitaxel was peaked at 6 hours and returned to normal by 24 hours and paclitaxel induced minimal apoptosis. Radiation induced apoptosis, peaked at 6 hours and returned to normal by 24 hours. Radiation-induced apoptosis was less in combined group which suggested that paclitaxel have a radioprotective effect when radiation was given 24 hours after paclitaxel infusion.