• 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.

• Imaging Science in Dentistry
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• v.31 no.1
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• pp.1-7
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• 2001

Purpose : To evaluate the usefulness of the reconstructed 3-dimensional image on the personal computer in comparison with that of the CT workstation by quantitative comparison and analysis. Materials and Methods : The spiral CT data obtained from 27 persons were transferred from the CT workstation to a personal computer, and they were reconstructed as 3-dimensional image on the personal computer using V-works 2.0/sup TM/. One observer obtained the 14 measurements on the reconstructed 3-dimensional image on both the CT workstation and the personal computer. Paired Nest was used to evaluate the intraobserver difference and the mean value of the each measurement on the CT workstation and the personal computer. Pearson correlation analysis and % incongruence were also performed. Results: I-Gn, N-Gn, N-A, N-Ns, B-A, and G-Op did not show any statistically significant difference (p>0.05), B-O, B-N, Eu-Eu, Zy-Zy, Biw, D-D, Orbrd R, and L had statistically significant difference (p<0.05), but the mean values of the differences of all measurements were below 2 mm, except for D-D. The value of correlation coefficient y was greater than 0.95 at I-Gn, N-Gn, N-A, N-Ns, B-A, B-N, G-Op, Eu-Eu, Zy-Zy, and Biw, and it was 0.75 at B-O, 0.78 at D-D, and 0.82 at both Orbrd Rand L. The % incongruence was below 4% at I-Gn, N-Gn, N-A, N-Ns, B-A, B-N, G-Op, Eu-Eu, Zy-Zy, and Biw, and 7.18%, 10.78%, 4.97%, 5.89% at B-O, D-D, Orbrd Rand L respectively. Conclusion : It can be considered that the utilization of the personal computer has great usefulness in reconstruction of the 3-dimensional image when it comes to the economics, accessibility and convenience, except for thin bones and the landmarks which are difficult to be located.

• Journal of radiological science and technology
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• v.45 no.5
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• pp.423-431
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• 2022

The purpose of this study is to present objective information in applying 3D printing technology for PET/CT (Positron Emission Tomography/Computed Tomography) performance evaluation and use it as a basic research that can be applied to various purposes in the future. Phantoms were manufactured with step wedge of ABS(Acrylonitrile Butadiene Styrene) and ACR(Acrylic acid) material. The counts for each ROI(Region of Interest) were analyzed through image acquisition in PET/CT. And the variation rate of counts and CNR(Contrast Noise Ratio) was evaluated. In the counts analysis, the effect of thickness occurred. In addition, in the variation rate analysis, the thickness setting of steps wedge 4 to 5 levels should be considered first. These results minimize quantitative and qualitative changes in the phantom manufactured based on 3D printing, and enable more stable PET/CT performance evaluation. Based on 3D printing in PET/CT, various phantoms are expected to be produced in the future. If the characteristics of each material are considered and applied through the basic research such as this research, the result of the phantom manufactured through 3D printing can be more meaningful and will be used in a wide range.

• The korean journal of orthodontics
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• v.38 no.4
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• pp.265-274
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• 2008

Objective: The aim of this study was to evaluate the potency of panoramic radiography for the detection of maxillary impacted canines. Methods: Twenty-five patients were selected, comprised of 7 males (mean age: 10.9 years, range: 8.5 - 14.5 years) and 18 females (mean age: 10.9 years, range: 8.2 - 15.7 years). In total, thirty-five maxillary impacted canines were estimated. The position of the canine and root resorption of adjacent teeth were evaluated on panoramic radiography and 3D CT. Results: Except for angulation to the occlusal plane, the other parameters, such as tooth length, crown width, vertical distance and lateral shift showed larger values on panoramic radiography compared to 3D CT. In palatally impacted cases, the angulation of canine was smaller, and the vertical distance to the occlusal place was larger on panoramic radiography than 3D CT. For labially impacted canines, tooth length, crown width, and angulation to the occlusal plane were similar for the two methods. The sensitivity for detecting root resorption on panoramic radiography was calculated as being 33.3% of 3D CT. Conclusions: The position of labially impacted canines can be effectively estimated using panoramic radiography, but palatally impacted canines need further investigation such as 3D CT for proper diagnosis.

• The Journal of the Korea Contents Association
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• v.10 no.9
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• pp.259-266
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• 2010

The study focuses on the value of Micro CT, a high resolution X-ray imaging device, by using it on rats to observe the overall portal vein image of the liver and the microvasculature of each lobes, visualize the 4 segmental lobes and acquire 3D image of the microvasculature through the reconstruction of sectional image data. Less of the damage to liver of the 5 mice, the device was able to separate the liver into 4 segmental lobes and displayed the 4 portal vein microvasculature in 2D. By using the 3D MIP technique, observation of the whole portal vein system microvasculature in 3D image was made possible along with each of the portal vein segment's branches until the 6th branch. Measured the size of 6branch, the average was measured at 1branch : $0.51mm{\pm}0.08$, 2 branch : $0.32mm{\pm}0.12$, 3 branch : $0.23mm{\pm}0.11$, 4 branch : $0.19mm{\pm}0.08$, 5 branch : $0.13mm{\pm}0.06$, 6 branch : $70.5{\mu}m{\pm}14.1$. The 3D image and the images of the microvasculatures in the result of study proved that the Micro-CT can be considered many useful device in obtaining high resolution images.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.376-378
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• 2002

This work was carried out to evaluate the basic performances for 4D CT, which employed continuously rotating conebeam. The performances were evaluated with the same method as the conventional CT, because the standard method of evaluating 4D CT has not yet been established, and we think this result was helpful to establish it. 4D CT can give dynamic volume imaging data continuously and with high-speed. The results were isotropic except for the evaluation of distortion in which small distortions gradually appeared as coming off the center of phantom in longitudinal direction.

• Progress in Medical Physics
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• v.25 no.1
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• pp.53-63
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• 2014

The objective of this study is to investigate the difference of ITV lengths and ITVs between 4DCT and Slow-CT images according to respiratory patterns using a respiratory motion phantom. The respiratory periods 1~4 s and target motion 1~3 cm were applied on each respiratory pattern. 4DCT and Slow-CT images were acquired for 3 times. 4DCT and Slow-CT ITVs were measured with contouring the target in the Eclipse RTP system. The measured ITV lenghts and ITVs in 4DCT and Slow-CT images were compared to the known values. For the ITV lengths and ITVs in the 4DCT, the difference of them were reduced as the respiratory period is longer and target motion is shorter. For the Slow-CT, there was same tendency with change in 4DCT ITV lengths and ITVs about target motion. However, the difference of ITV lengths and ITVs for the respiratory periods were the lowest in respiratory period 1 second and different slightly within respiratory period 2-4 seconds. According to the respiratory patterns, pattern A had the highest reproducibility. Pattern B, C and D were showed the difference similar to each other. However, for pattern E, the reproducibility was the lowest compared with other four patterns. The difference of ITV lengths and ITVs between Slow-CT and 4DCT was increased by increasing the respiratory periods and target motion for all respiratory patterns. When the difference of Slow-CT ITV lengths and ITVs were compared with that of 4DCT ITV lengths and ITVs, Slow-CT ITV lengths and ITVs were approximately 22 % smaller than 4DCT, and the representations of target were different in each pattern. In case of pattern A, B and C, length difference was 3 mm at S (superior) and I (inferior) direction, and the length difference of pattern D was 1.45 cm at only "I" direction whereas the length difference of pattern E was 5 mm longer in "S" direction than "I" direction. Therefore, the margin in SI directions should be determined by considering the respiratory patterns when the margin of Slow-CT is compensated for 4DCT ITV lengths. Afterward, we think that the result of this study will be useful to analyze the ITV lengths and ITVs from the CT images on the basis of the patient respiratory signals.

• Journal of Computing Science and Engineering
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• v.4 no.4
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• pp.368-387
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• 2010

We propose a novel method for the registration of 3D CT scans to 2D endoscopic images during the image-guided medialization laryngoplasty. This study aims to allow the surgeon to find the precise configuration of the implant and place it into the desired location by employing accurate registration methods of the 3D CT data to intra-operative patient and interactive visualization tools for the registered images. In this study, the proposed registration methods enable the surgeon to compare the outcome of the procedure to the pre-planned shape by matching the vocal folds in the CT rendered images to the endoscopic images. The 3D image fusion provides an interactive and intuitive guidance for surgeon by visualizing a combined and correlated relationship of the multiple imaging modalities. The 3D Magic Lens helps to effectively visualize laryngeal anatomical structures by applying different transparencies and transfer functions to the region of interest. The preliminary results of the study demonstrated that the proposed method can be readily extended for image-guided surgery of real patients.

• The Journal of the Korea Contents Association
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• v.15 no.11
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• pp.313-321
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• 2015

To minimize CT examination for Hip FAI diagnosis and operation plan. also, whether the MRI 3D images can replace Hip Clock face image was evaluated when performing Hip FAI MRI by using additional 3D image. This study analyzed Hip MRI and 3D Hip CT images of 31 patients in this hospital. For the purpose of evaluating the images, one orthopedic surgeon and one radiology specialist reconstructed Clock face, at MR and CT modality, by superior 12 o'clock, labrum front 3 o'clock, and the other side 9 o'clock, centering on Hip joint articular transverse ligament 6 o'clock. Afterwards, by the Likert Scale 5 point scale (independent t-test p<0.005), this study evaluated the check-up of A. retinacular vessel, B. head neck junction at 11 o'clock, A. Epiphyseal line, B. Cam lesion at 12 o'clock, and Cam lesion, Posterior Cam lesion at 1,2,3 and 4 o'clock. As for the verification of reliability among observers, this study verified coincidence by Cohen's weighted Kappa verification. As a result of Likert scale for the purpose of qualitative evaluation about the image, 11 o'clock A. retinacular vessel MR average was $3.69{\pm}1.0$ and CT average was $2.8{\pm}0.78$. B. head neck juncton didn't have a difference between two observers (p <0.416). 12 o'clock A. Epiphyseal line MR average was $3.54{\pm}1.00$ and CT average was $4.5{\pm}0.62$(p<0.000). B. Cam lesion didn't have a difference between two observers (p <0.532). 1,2,3,4 Cam lesion and Posterior Cam lesion were not statistically significant (p <0.656, p <0.658). As a result of weighted Kappa verification, 11 o'clock A.retinacular vessel CT K value was 0.663 and the lowest conformity. As a result of coincidence evaluation on respective item, a very high result was drawn, and two observers showed high reliability.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.1
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• pp.10-18
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• 2014

Purpose: Among different PET/CT devices which are composed of same PET model but different CT models, SUV, usually used for quantitative evaluation, was measured to assess the accuracy of follow up scans in different PET/CT and confirm that interequipment compatibility is useful in arranging the PET/CT exam appointment. Materials and Methods: Using ACR PET Phantom, PET NEMA IEC Body Phantom, SNM Chest Phantom and Ge-68 cylinder Phantom, $SUV_{mean}$ and $SUV_{max}$ was measured by 3 different models of PET/CT (Discovery 690, Discovery 690Elite and Discovery 710, GE) made in same company. ANOVA was used to evaluate the significant difference in the result. Results: In the result, the average of $SUV_{max}$ was D690 (25 mm-1.82, 16 mm-1.75, 12 mm-1.73, 8 mm-1.44), D690E (25 mm-1.76, 16 mm-1.92, 12 mm-1.78, 8 mm-1.55) and D710 (25 mm-1.84, 16 mm-1.89, 12 mm-1.77, 8 mm-1.61) in ACR Phantom, D690 (25 mm-2.26, 16 mm-2.25, 12 mm-1.92, 8 mm-1.85), D690E (25 mm-2.45, 16 mm-2.25, 12 mm-2.05 8 mm-1.91) and D710(25 mm-2.49, 16 mm-2.20, 1 2mm-2.30, 8 mm-2.05) in PET NEMA IEC Body Phantom, D690-1.04, D690E-1.10 and D710-1.09 in SNM Chest Phantom and D690-0.81, D690E-0.81, D710-0.84 in Ge-68 cylinder Phantom. The differences between average SUV of 4 phantoms were $SUV_{mean}$-1.87%, $SUV_{max}$-2.15%. And also as a result of ANOVA analysis, there was no significant difference statistically. Conclusion: If different models of PET/CT have same specification of PET system, there was no significant difference in $SUV_{mean}$ and $SUV_{max}$ even though they have different CT system. And also differences of $SUV_{mean}$ and $SUV_{max}$ in phantom images were under 5% which many manufacturers recommend. Therefore, follow up scan will be possible using different PET/CT if it has same specification of PET system with the previous PET/CT. This information will enable the accurate comparative analysis when conducting follow up scans and be helpful to schedule PET/CT exam more effectively.