• Journal of Radiation Protection and Research
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• 제36권3호
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• pp.107-118
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• 2011

Conventional (SRS) and fractionated (FSRS) stereotactic radiosurgery necessarily require stringent overall target point accuracy and precision. We determine three-dimensional intracranial target point deviations (TPDs) in a whole treatment procedure using magnetic resonance image (MRI)-based polymer-gel dosimetry, and suggest a technique for overall system tests. TPDs were measured using a custom-made head phantom and gel dosimetry. We calculated TPDs using a treatment planning system. Then, we compared TPDs using mid bi-plane and three-dimensional volume methods with spherical and elliptical targets to determine their inherent analysis errors; finally, we analyzed regional TPDs using the latter method. Average and maximum additive errors for ellipses were 0.62 and 0.69 mm, respectively. Total displacements were 0.92 ${\pm}$ 0.25 and 0.77 ${\pm}$ 0.15 mm for virtual SRS and FSRS, respectively. Average TPDtotal at peripheral regions was greater than that at central regions for both. Overall system accuracy was similar to that reported previously. Our technique could be used as an overall system accuracy test that considers the real radiation field shape.

• 한국운동역학회지
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• 제22권2호
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• pp.151-158
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• 2012

The purpose of this study was to investigate variables of significantly difference as the structure of the spine, pelvic deviation and foot pressure between undergraduates and golf player subjects. The subjects of study were composed of 20 male golf players and 20 male undergraduates. Both groups were right handed persons. The measurement tools of this study were Formetric 4D(Diers, Germany) which is a three dimensional measure. The result are the follows: there were a significant difference between golf players and general students of trunk imbalance, pelvic tilt, pelvic torsion, pelvic rotation, surface rotation, lumbar lordotic curve, foot pressure(fore & behind foot), weight distribution(right & left foot). In conclusion, golf players might cause transform of spine and foot pressure due to golf exercise for several years. Such as imbalance affect to induce functional impairment and pain of musculoskeletal system, and appropriate evaluation and treatment were necessary for golf players.

• Journal of Multimedia Information System
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• 제3권2호
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• pp.43-46
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• 2016

This article will compare the following visual categories: visual angle, distinguishable details, sensitivity, and dynamic range. These categories are often considered within the subject of the maximum deviation from the camera eye, an issue which has generated much controversy. Other characteristics such as depth of field, three-dimensional vision, white balance and color, are not considered in this article.

• 상하수도학회지
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• 제18권4호
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• pp.500-507
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• 2004

This study was conducted to evaluate the equity of the flow distribution from rapid mixing basin to the flocculation basins. Also, several types of inlet structures of the open channel affecting the flow pattern and distribution trend were studied using Computational Fluid Dynamics (CFD) simulation. For investigating the factual phenomena in distribution channel, we selected a certain domestic water treatment plant with capacity of $361,000m^3/d$. From the measurements of flow discharge, it is investigated that this existing inlet geometry resulted in significant inequitable distribution. The both largest deviations in the basins and rows were over 10%. In order to reduce the these deviation, this study suggested installing a baffle against the influent, and showed the effectiveness which the largest deviation was less than 3%. Also, it was concluded that the existing design method of open channel could be improved by three-dimensional hydrodynamic analysis for optimizing the even flow.

• 대한치과기공학회지
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• 제43권3호
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• pp.84-92
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• 2021

Purpose: The purpose of this study was to compare the dimension safety evaluation between a general ultrasonic cleaner and an ultrasonic cleaner equipped with UV-C (ultraviolet-C). Methods: An edentulous model was prepared. A denture base and an occlusal rim were fabricated, and scanning was performed. After scanning, a denture base and full arch artificial teeth were designed. The full arch artificial teeth were printed using a three-dimensional printer (n=10). The residual resin was washed with alcohol and then scanned (reference data). The printed specimens were classified and cleaned using a general ultrasonic cleaner (GU group) and an ultrasonic cleaner equipped with UV-C (UC group). After each washing, a rescan was performed (scan data). Reference data and scan data were superimposed using overlapping software. Data were statistically analyzed using the Mann-Whitney test (α=0.05). Results: In the deviation values of full arch artificial teeth, the GU group showed a high deviation of 18.02 ㎛ and the UC group showed a low deviation of 15.02 ㎛. The two groups demonstrated a statistically significant difference (p<0.05). Conclusion: Full arch artificial teeth prepared using photopolymerized resin were deformed according to the temperature of water generated in the ultrasonic cleaner. It is judged that there is no deformation according to the UV-C ultrasonic cleaner.

• 대한두개안면성형외과학회지
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• 제20권1호
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• pp.31-36
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• 2019

Background: After closed reduction, patients are sometimes concerned that their external nasal shapes have changed. The aim of this study was to investigate and explain changes in nasal shape after surgery through objective photogrammetric anthropometry measurements taken through three-dimensional (3D) reformed computed tomography (CT) images. Methods: Our study included 100 Korean patients who underwent closed reduction of isolated nasal bone fracture from January 2016 to June 2017. Using the ruler tool in Adobe Photoshop CS3, we measured preoperative and postoperative nasal base heights, long nostril axis lengths, both nasal alar angles, and amount of nasal deviation through the 3D reformation of soft tissue via CT scans. We then compared the dimension of nose. Results: The amount of postoperative correction for nasal base height was 1.192 mm. The differences in nostril length between each side were found to be 0.333 mm preoperatively and 0.323 mm postoperatively. The differences in the nasal alar angle between each side was $1.382^{\circ}$ preoperatively and $1.043^{\circ}$ postoperatively. The amount of nasal deviation was found to be 5.248 mm preoperatively and 1.024 mm in postoperatively. Conclusion: After the reduction of nasal bone fractures, changes in nasal dimensions were noticeable in terms of nasal deviation but less significant in nasal tips, except for changes in nasal alar angles, which were notable.

• Imaging Science in Dentistry
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• 제46권1호
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• pp.33-38
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• 2016

Purpose: Facial asymmetry has been measured by the severity of deviation of the menton (Me) on posteroanterior (PA) cephalograms and three-dimensional (3D) computed tomography (CT). This study aimed to compare PA cephalograms and 3D CT regarding the severity of Me deviation and the direction of the Me. Materials and Methods: PA cephalograms and 3D CT images of 35 patients who underwent orthognathic surgery (19 males and 16 females, with an average age of $22.1{\pm}3.3years$) were retrospectively reviewed in this study. By measuring the distance and direction of the Me from the midfacial reference line and the midsagittal plane in the cephalograms and 3D CT, respectively, the x-coordinates ($x_1$ and $x_2$) of the Me were obtained in each image. The difference between the x-coordinates was calculated and statistical analysis was performed to compare the severity of Me deviation and the direction of the Me in the two imaging modalities. Results: A statistically significant difference in the severity of Me deviation was found between the two imaging modalities (${\Delta}x=2.45{\pm}2.03mm$, p<0.05) using the one-sample t-test. Statistically significant agreement was observed in the presence of deviation (k=0.64, p<0.05) and in the severity of Me deviation (k=0.27, p<0.05). A difference in the direction of the Me was detected in three patients (8.6%). The severity of the Me deviation was found to vary according to the imaging modality in 16 patients (45.7%). Conclusion: The measurement of Me deviation may be different between PA cephalograms and 3D CT in some patients.

• 대한치과교정학회지
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• 제46권1호
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• pp.3-12
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• 2016

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, $29.84{\pm}12.08{\mu}m$) proved to be less precise than the Trios$^{(R)}$ scanner ($22.17{\pm}4.47{\mu}m$). 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.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권4호
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• pp.307-311
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• 2007

Purpose: The aim of this study was simply assessing linear measurements in the lateral and medial approach, respectively, for bone harvesting using anatomic and three-dimensional(3D) computed tomographic(CT) analyses on a dried cadaveric proximal tibia. In addition, the availability of the three-dimensional computed tomographic(3D-CT) analysis was also estimated. Materials and methods: Ten dried proximal tibia were obtained from five Korean cadavers. Four the reference points, the SM(superior-medial), IM(inferior-medial), SL(superior-lateral), and IL(inferior-lateral) were marked around the tibial tuberosity. The PM(posterior-medial) and PL(posterior-lateral) points were randomly marked at points farthest from the lateral and medial reference points, respectively, in the posterior border of the superior articular surface of both condyles. All measurements were obtained on the dried proximal tibia. After computed tomography had been performed, the three dimensional images were reconstructed using V works $4.0^{TM}$(Cybermed Inc., Seoul, Korea), and the length between the reference points were measured three dimensionally using the method described above. The error between the mean actual and mean 3D-CT measurements was calculated in order to determine the availability of the three dimensional computed tomographic analysis. Results: The length between the reference points was greatest at the IL-PM, which averaged $65.39mm{\pm}10.35$. This was followed by the SL-PM with $63.24mm{\pm}8.10$, the IM-PL with $58.09mm{\pm}10.02$, and the SM-PL with $51.99mm{\pm}9.06$. The differences between the IL-PM and SM-PL were 13.4 mm. The mean values were 55.04 mm in the medial approach and 64.32 mm in the lateral approach, and the differences between medial and lateral were 9.28 mm. The error between the mean actual and mean 3D-CT measurements was 0.31% and the standard deviation was 0.28%. Conclusion: The anatomical and three dimensional computed tomographic analysis indicates that there was only a 9.28 mm linear difference between the lateral and medial approach. This is consistent with previous studies, which showed that there was little difference between the two approaches in terms of the bone volume. In addition, the error(0.31%) and the standard deviation(0.28%) were considered low, demonstrating high accuracy of 3D-CT. Therefore it can be used in preoperative treatment planning.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제41권
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• pp.57.1-57.8
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• 2019

Background: The relationship between the lateral deviation of chin and the upper and middle facial third asymmetry is still controversial. The purpose of this study is to evaluate the correlation of upper and middle facial third asymmetry with lateral deviation of chin using 3-dimensional computed tomography. The study was conducted on patients who underwent orthognathic surgery from January 2016 to August 2017. A total of 40 patients were included in this retrospective study. A spiral scanner was used to obtain the 3-dimensional computed tomography scans. The landmarks were assigned on the reconstructed 3-dimensional images, and their locations were verified on the axial, midsagittal, and coronal slices. The Pearson correlation analysis was performed to evaluate the correlation between chin deviation and difference between the measurements of distances in paired craniofacial structures. Statistical analysis was performed at a significance level of 5%. Results: In mandible, the degree of chin deviation was correlated with the mandibular length and mandibular body length. Mandibular length and mandibular body length are shorter on the deviated-chin side compared to that on the non-deviated side (mandibular length, r = -0.897, p value < 0.001; mandibular body length, r = -0.318, p value = 0.045). In the upper and middle facial thirds, the degree of chin deviation was correlated with the vertical asymmetry of the glenoid fossa and zygonion. Glenoid fossa and zygonion are superior on the deviated-chin side than on the non-deviated side (glenoid fossa, r = 0.317, p value = 0.046; zygonion, r = 0.357, p value = 0.024). Conclusion: Lateral deviation of chin is correlated with upper and middle facial third asymmetry as well as lower facial third asymmetry. As a result, treatment planning in patients with chin deviation should involve a careful evaluation of the asymmetry of the upper and middle facial thirds to ensure complete patient satisfaction.