• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.6
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• pp.123-128
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• 2020

In this paper, we presents a new cone beam computerized tomography (CBCT) system for the reconstruction of 3 dimensional dynamic images. The system using cone beam has less the exposure of radioactivity than fan beam, relatively. In the system, the reconstruction 3-D image is reconstructed with the radiation angle of X-ray in the image processing unit and transmitted to the monitor. And in the image processing unit, the Three Pass Shear Matrices, a kind of Rotation-based method, is applied to reconstruct 3D image because it has less transcendental functions than the one-pass shear matrix to decrease a time of calculations for the reconstruction 3-D image in the processor. The new system is able to get 3~5 3-D images a second, reconstruct the 3-D dynamic images in real time. And we showed the Rotation-based method was good rather than existing reconstruction technique for 3D images, also found weakness and a solution for it.

• Journal of Biomedical Engineering Research
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• v.27 no.6
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• pp.392-401
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• 2006

Image Guided Surgery (IGS) system which has variously tried in medical engineering fields is able to give a surgeon objective information of operation process like decision making and surgical planning. This information is displayed through 3D images which are acquired from image modalities like CT and MRI for pre-operation. The technique of image registration is necessary to construct IGS system. Image registration means that 3D model and the object operated by a surgeon are matched on the common frame. Major techniques of registration in IGS system have been used by recognizing fiducial markers placed on the object. However, this method has been criticized due to additional trauma, its invasive protocol inserting fiducial markers in patient's bone and generating noise data when 2D slice images are acquired by image modality because many markers are made of metal. Therefore, this paper developed shape-based registration technique to improve the limitation of fiducial marker based IGS system. Iterative Closest Points (ICP) algorithm was used to match corresponding points and quaternion based rotation and translation transformation using closed form solution applied to find the optimized cost function of transformation. we assumed that this algorithm were used in Total Knee replacement (TKR) operation. Accordingly, we have developed region-based 3D registration technique based on anatomical landmarks and this registration algorithm was evaluated in a femur model. It was found that region-based algorithm can improve the accuracy in 3D registration.

• Journal of Biomedical Engineering Research
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• v.11 no.1
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• pp.71-74
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• 1990

In the medical modalities, three-dimensional objects must be reconstructed from the consecutive slices. but the slime separation is usually much greater than the pixel size within an individual slices. In this paper, an interpolation scheme for filling the spare between the shapes in two successive slices is developed. It minimizes the computation involvement in segmentation of 3-D reconst ructlon process as well as more accurately approximates the object than the linear interpolation method.

• Journal of Radiation Protection and Research
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• v.35 no.2
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• pp.63-68
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• 2010

The ultimate goal of radiation treatment is to use enough radiation dosage in order to examine a tumor while protecting normal tissue. Respiratory guided radiotherapy is being clinically implemented to examine a given stabilized area in order to compensate for the problems of patient breathing. This study investigates the effects of breathing movements on 40 patients with liver cancer through the actual radiation therapy plan using 4D-CT and respiratory guided radiotherapy using RPM. Using a commercial RPM respiratory gating system 4D-CT, we acquired 4D CT on multislice helical CT scanners that use different approaches to 4D CT image reconstruction. The results from analyzing forty patients according to age and direction showed no relationship between gender and transition change. The mean left-right, anteroposterior, and craniocaudal total movements were $3.19{\pm}1.29$, $5.44{\pm}2.07$, and $12.54{\pm}4.70$ mm, respectively. Changes were the largest with CC directions and as patients advanced in age, movements were larger. Therefore, as changes occur in treatment areas because of movements caused from breathing, respiratory gating system is put into operation to revise movement and can increase the radiotherapeutics effects in treating liver cancer.

• The korean journal of orthodontics
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• v.35 no.4 s.111
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• pp.251-261
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• 2005

Enlargement is an inherent property of X-rays which occurs when straight hues diverse from small a focal spot. The purpose of the present study was to evaluate the validity of the correction of gonial angle width enlarged on frontal cephalogram, using frontal and lateral cephalograms taken orthogonally from each other. In 40 adult individuals, frontal and lateral cephalograms were taken at a $90^{\circ}$ angle using the Head Posture Aligner. The angle width was measured on the frontal cephalogram and subsequently. the corrected angle width was calculated using the magnification rate of two cephalograms. Measured and corrected angle widths were compared with the measurement from the 3D CT image. The measurement or the frontal cephalogram showed a 9.10mm of enlargement on average ranging from 7.92 to 11.31mm. Corrected angle width measurement showed a 0.14mm difference with the 3D CT image measurement, which was not statistically significant. The results of the study indicate that actual au91e width can be approached through calculation using frontal and lateral cephalograms taken orthogonally with the help of the Head Posture Aligner The study also showed that the magnitude of correction error did not show a significant correlation with the amount of menton deviation, and it suggests that the present correction method is valid even in individuals with severe facial asymmetry.

• The Journal of Korean Society for Radiation Therapy
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• v.21 no.2
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• pp.83-88
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• 2009

Purpose: Cone beam computed tomography (CBCT) using an on board imager (OBI) can check the movement and setup error in patient position and target volume by comparing with the image of computer simulation treatment in real.time during patient treatment. Thus, this study purposed to check the change and movement of patient position and target volume using CBCT in IMRT and calculate difference from the treatment plan, and then to correct the position using an automated match system and to test the accuracy of position correction using an electronic portal imaging device (EPID) and examine the usefulness of CBCT in IMRT and the accuracy of the automatic match system. Materials and Methods: The subjects of this study were 3 head and neck patients and 1 pelvis patient sampled from IMRT patients treated in our hospital. In order to investigate the movement of treatment position and resultant displacement of irradiated volume, we took CBCT using OBI mounted on the linear accelerator. Before each IMRT treatment, we took CBCT and checked difference from the treatment plan by coordinate by comparing it with the image of CT simulation. Then, we made correction through the automatic match system of 3D/3D match to match the treatment plan, and verified and evaluated using electronic portal imaging device. Results: When CBCT was compared with the image of CT simulation before treatment, the average difference by coordinate in the head and neck was 0.99 mm vertically, 1.14 mm longitudinally, 4.91 mm laterally, and 1.07o in the rotational direction, showing somewhat insignificant differences by part. In testing after correction, when the image from the electronic portal imaging device was compared with DRR image, it was found that correction had been made accurately with error less than 0.5 mm. Conclusion: By comparing a CBCT image before treatment with a 3D image reconstructed into a volume instead of a 2D image for the patient's setup error and change in the position of the organs and the target, we could measure and correct the change of position and target volume and treat more accurately, and could calculate and compare the errors. The results of this study show that CBCT was useful to deliver accurate treatment according to the treatment plan and to increase the reproducibility of repeated treatment, and satisfactory results were obtained. Accuracy enhanced through CBCT is highly required in IMRT, in which the shape of the target volume is complex and the change of dose distribution is radical. In addition, further research is required on the criteria for match focus by treatment site and treatment purpose.

• Tunnel and Underground Space
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• v.27 no.5
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• pp.333-342
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• 2017

In this study, the heterogeneity of internal structure of various igneous rocks acquired in Korea was quantified and correlated with the seismic velocity and the point load strength. Three-dimensional X-ray Computed Tomography (CT) was used to obtain information on the internal structure of the rock specimen, and the representative unit length (LR) was calculated by applying a statistical technique to the CT images. We also proposed an estimation equation to predict the mechanical properties of rocks from the relationship between LR, acoustic velocity and point load strength. In the proposed method, it is shown that the characterization of internal structure of rocks could be utilized as an indirect index to account for the mechanical behavior of rocks by substituting physical laboratory testing for non-destructive test.

• The KIPS Transactions:PartB
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• v.15B no.6
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• pp.553-560
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• 2008

The amount of image data used in medical institution is increasing rapidly with great development of medical technology. Therefore, an automation method that use image processing description, rather than manual macrography of doctors, is required for the analysis large medical data. Specially, medical image registration, which is the process of finding the spatial transform that maps points from one image to the corresponding points in another image, and 3D analysis and visualization skills for a series of 2D images are essential technologies. However, a high establishment cost raise a budget problem, and hence small scaled hospitals hesitate importing these medical visualizing system. In this paper, we propose a visualization system which allows user to manage datasets and manipulates medical images registration using an open source graphics tool - VTK(Visualization Tool Kit). The propose of our research is to get more accurate 3D diagnosis system in less expensive price, compared to existing systems.

• Journal of Information Technology Applications and Management
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• v.29 no.6
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• pp.135-144
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• 2022

In this study, we transformed 4680 type lithium-ion batteries to 3-dimensional CAD models and present a methodology to detect defects using Radon inverse transformation. Transparency was applied to the model to make it look like a CT image when viewed from the front. One normal and three defect models were created and analyzed. The models were saved as image files while rotating at a certain angle. Then, we used the Radon inverse transformation to reconstruct the original 3D geometry from the image files. Finally, we successfully found defects in the defect models for three cases.

• Journal of Korean Neurosurgical Society
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• v.63 no.2
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• pp.237-247
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• 2020

Objective : Fixation of the C1-2 segment is challenging because of the complex anatomy in the region and the need for a high degree of accuracy to avoid complications. Preoperative 3D-computed tomography (CT) scans can help reduce the risk of complications in the vertebral artery, spinal cord, and nerve roots. However, the patient may be susceptible to injury if the patient's anatomy does not match the preoperative CT scans. The intraoperative 3D image-based navigation systems have reduced complications in instrument-assisted techniques due to greater accuracy. This study aimed to compare the radiologic outcomes of C1-2 fusion surgery between intraoperative CT image-guided operation and fluoroscopy-guided operation. Methods : We retrospectively reviewed the radiologic images of 34 patients who underwent C1-2 fusion spine surgery from January 2009 to November 2018 at our hospital. We assessed 17 cases each of degenerative cervical disease and trauma in a study population of 18 males and 16 females. The mean age was 54.8 years. A total of 139 screws were used and the surgical procedures included 68 screws in the C1 lateral mass, 58 screws in C2 pedicle, nine screws in C2 lamina and C2 pars screws, four lateral mass screws in sub-axial level. Of the 34 patients, 19 patients underwent screw insertion using intraoperative mobile CT. Other patients underwent atlantoaxial fusion with a standard fluoroscopy-guided device. Results : A total of 139 screws were correctly positioned. We analyzed the positions of 135 screws except for the four screws that performed the lateral mass screws in C3 vertebra. Minor screw penetration was observed in seven cases (5.2%), and major pedicle screw penetration was observed in three cases (2.2%). In one case, the malposition of a C2 pedicle screw was confirmed, which was subsequently corrected. There were no complications regarding vertebral artery injury or onset of new neurologic deficits. The screw malposition rate was lower (5.3%) in patients who underwent intraoperative CT-based navigation than that for fluoroscopy-guided cases (10.2%). And we confirmed that the operation time can be significantly reduced by surgery using intraoperative O-arm device. Conclusion : Spinal navigation using intraoperative cone-beam CT scans is reliable for posterior fixation in unstable C1-2 pathologies and can be reduced the operative time.