• Journal of radiological science and technology
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• v.39 no.3
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• pp.329-336
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• 2016

The purpose of this study was to evaluate the usefulness of low-dose CT (LDCT) for emphysema compared with high-resolution CT (HRCT). Measurements of radiation dose and noise were repeated 3 times in same exposure condition which was similar with obtaining HRCT and LDCT images. We analysed reading results of 146 subjects. Six images per participants selected for emphysema grading. Emphysema was graded for all 6 zones on the left and right sides of the lungs by the consensus reading of two chest radiologists using a 4-point scale. Between the HRCT and LDCT images, diagnostic differences and agreements for emphysema were analyzed by McNemar's and unweighted kappa tests, and radiation doses and noise by a Mann-Whitney U-test, using the SPSS 19.0 program. Radiation dose from HRCT was significantly higher than that of LDCT, but the noise was significantly lower in HRCT than in LDCT. Diagnostic agreement for emphysema between HRCT and LDCT images was excellent (k-value=0.88). Emphysema grading scores were not significantly different between HRCT and LDCT images for all six lung zones. Emphysema grading scores from LDCT images were significantly correlated with increased scores on HRCT images (r=0.599, p < 0.001). Considering the tradeoff between radiation dose and image noise, LDCT could be used as the gold standard method instead of HRCT for emphysema detection and grading.

• Journal of Mechanical Science and Technology
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• v.16 no.12
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• pp.1627-1632
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• 2002

In this paper, a simplified ultrasonic CT system, which uses the information in three directions, that is, 90°, ＋45° and －45°about the inspection plane, is applied to the high strength steel, and the frequency analysis method for enhancing the C scan or CT image is developed. This frequency analysis method is based on the frequency response property of the material. By comparing the magnitudes in the frequency domain, the special frequency which shows a significant difference between the welded joint and base material was found and used to obtain a C scan or CT image. Experimental results for several kinds of specimens, having a welded joint by electron beam welding, a weld joint by arc welding, on a fatigue crack, showed that the obtained C scan or CT image has better resolution than the results of previous experiments using the maximum value of the received waveform.

• The Korean Journal of Nuclear Medicine Technology
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• v.12 no.3
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• pp.184-191
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• 2008

Purpose: To evaluate the degree of malignancy of incident thyroid lesion found in $^{18}F$-FDG PET/CT findings and the usefulness of the method suggested in this study, we applicate the Delay Scan Method that differentiate a false positive benign tumor, inflammation and malignancy, as well as make the criteria of SUV. Materials and Methods: A retrograde study was conducted of 800 patients who were admitted in E hospital to receive $^{18}F$-FDG PET/CT examination. One patient who was diagnosed as primary thyroid cancer and received $^{18}F$-FDG PET/CT examination was excluded. The number of final patients of this study was 799, the reasons of $^{18}F$-FDG PET/CT examination of these patients were follow-up of old cancer or suspicious tumorous lesion in 696 and disease screening in 103. $^{18}F$-FDG PET/CT image photographing was taken in Biograph-Duo made by SIEMENS, after taking normal $^{18}F$-FDG PET/CT image (1 hr) and then 1 hr later we took the thyroid 1 bed-delayed image for the patients who showed abnormal thyroid $^{18}F$-FDG uptake and above 2.0 SUV for 2 minutes every 1 bed. For the patients who showed abnormal thyroid uptake and above 2.0 SUV, 1 hr later, we took a 1 bed-delayed image and then made a comparative study between measured $SUV_{max}$ of 1 hr-abnormal uptake image and that of 2 hr-delayed image. Results and Conclusion: In this $^{18}F$-FDG PET/CT study among the patients who showed incidental $^{18}F$-FDG thyroidal uptake the number of thyroid incidentaloma was 5 (0.63%), all of then showed benign findings. And in the case of incidental $^{18}F$-FDG uptake in thyroid, $SUV_{max}$ variance obtained from 2 hr delayed image can be a indirect criteria in differentiating benign tumor from malignancy and decrease finding error. In the cases found thyroid incidentaloma when 1) $SUV_{max}$ of focal thyroid lesion is above 5.0 and 2) $SUV_{max}$ variance between normal $^{18}F$-FDG PET/CT exam and 2 hr delayed is $1.0{\pm}0.5$, they are suspected as malignancy and confirming biopsy is to be followed. Otherwise, I also think that distinct follow-up PET or CT image study is a reasonable diagnostic method.

• The Korean Journal of Nuclear Medicine Technology
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• v.12 no.3
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• pp.214-221
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• 2008

Purpose: We make a qualitative analysis of whether Fusion SPECT/CT can find lesion's anatomical sites better than existing SPECT or not, and we want to show the usefulness of SPECT/CT through finding out effects of CT attenuation correction on SPECT images. Materials and Method: 1. The evaluation of fusion images: This study comprised patients who was tested $^{131}I$-MIBG, Bone, $^{111}In$-Octreotide, Meckel's diverticulum, Parathyroid MIBI with Precedence 16 or Symbia T2 from 2008 Jan to Aug. We compared SPECT/CT image with non fusion image and make a qualitative analysis. 2. The evaluation of attenuation correction: We classified 38 patients who was tested 201Tl myocardial exam with Symbia T2 into 5 sections by using Cedars Sinai' QPS program - Ant, Inf, Lat, Septum, Apex. And we showed each section's perfusion states by percentage. We compared the each section's perfusion-states differences between CT AC and Non AC by average${\pm}$standard deviation. Results: 1. The evaluation of fusion images : In high energy $^{131}I$ cases, it was hard to grasp exact anatomical lesions due to difference between regions and surrounding lesions' uptake level. After combining with CT, we could grabs anatomical lesion more exactly. And in meckel's diverticulum case or to find lesions around bowels or organs with $^{111}In$ cases, it demonstrates its superiority. Bone SPECT/CT images help to distinguish between disk spaces certainly and give correct results. 2. The evaluation of attenuation correction: There is no significant difference statistically in Ant and Lat (p>0.05), but there is a meaningful difference in Inferior, Apex and Septum (p<0.05). AC perfusion at inferior wall in the 5 sections of myocardium: The perfusion difference between Non AC perfusion image ($68.58{\pm}7.55$) and CT corrected perfusion image ($76.84{\pm}6.52$) was the largest by $8.26{\pm}4.95$ (p<0.01, t=10.29). Conclusion: Nuclear medicine physicians can identify not only molecular image which shows functional activity of lesions but also anatomical location information of lesions with more accuracy using the combination of SPECT and CT systems. Of course this combination helps nuclear medicine physician find out the abnormal parts. Moreover combined data sets help separate between normal group and abnormal group in complicated body part. So clinicians can carry out diagnosis and treatment planning at the same time with a single test image. In addition, when we examine a myocardium in thorax where attenuation can occur easily, we can trust perfusion more in a certain region in SPECT test because CT provides the capability for accurate attenuation correction. In these reasons, we think we can prove the justice after treatment fusion image.

• Journal of radiological science and technology
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• v.14 no.1
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• pp.29-44
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• 1991

A Study on the distribution and types of the total 40 CT units, as of 1st October 1990, in Pusan area(29 for whole body CT units, 11 for brain CT units) were carried out during the period from January 1989 to December 1989 to find out the status of operation and utilization of whole body CT units. The results were as following ; 1. As of 1st October 1990 in Pusan area, a total of 40 CT units(29 for whole body CT units, 11 for brain CT units) were set up and operated. The number of cases of CT examination performed per day per unit were appeared to be less than 5 cases among 59.5% of CT units, and 2.7% of the total units has peformed more than 16 examinations. 2. The CT units under operation occupied 93.5% of the total and 2.6% of the total units was not properly been operated due to mechanical breakdown. This results is appeared to be better than other reports. 3. The average number of scanning per week for each CT were 35 cases and the average days under operation of the unit per week were 6.7 days. Consequently, the average days under operation of units was higher than that of the other reports, but the average number of scanning was lower. 4. The cases referred from other institutes to hospitals were 6.4% of total cases. 5. As a site of scanning, the brain appeared most frequently with 71.2% of the total cases and followed by spine 12.4%, abdomen 8.5%, and thorax 3.6%, respectively. 6. Positive rate by scanning was 70.8% of total cases, and it was 98.9% with thorax, abdomen 96.3%, spine 93.1%, and brain 38.4%, respectively. According to the results of this study, it is highly recommended that the regulations and the guidelines for setting-up of such high cost medical equipments as CT units be provided in order to ensure the cost-effectiveness of the system.

• Journal of the East Asian Society of Dietary Life
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• v.18 no.3
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• pp.345-352
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• 2008

This study investigated the utilization of tofu stake with turmeric manufacture by analyzing its effects on quality characteristics and shelf-life of tofu made with 0.5 CT(0.5% turmeric power), 1.0 CT(1.0% turmeric power), 1.5 CT(1.5% turmeric power), and 2.0 CT(2.0% turmeric power) in comparison with those ST(standard), In color lightness tofu stake springiness decreased with increasing turmeric power content, while cohesiveness was higher than ST. The gumminess of tofu stake decreased with increasing turmeric power content, while brittleness was higher than ST. Water content of turmeric power tofu stake was higher than ST. Weight of tofu stake increased with increasing turmeric power content, while cooking loss decreased with increasing turmeric power content. Thiobarbituric acid content of turmeric power tofu stake decreased with increasing turmeric power content. For overall acceptability, $0.5{\sim}1.0%$ turmeric power tofu stake attained the highest score.

• Journal of radiological science and technology
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• v.34 no.4
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• pp.305-314
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• 2011

The purpose of this study was to compare the findings on the chest low-dose CT (LDCT) images between the negative and positive groups for pneumoconiosis in the group exposed to inorganic dust. From May 30, 2007 to August 31, 2008, total 328 subjects were examined by a LDCT. LDCT images were read by a chest radiologist who has much experience for reading of pneumoconiosis. All subjects were classified into two groups based on digital images after consensus reading of two radiologists according to the ILO 2000 guidelines; negative group (87, 26.5%) without pneumoconiosis and positive group (241, 73.5%). Statistical analysis was performed using a SPSS 14.0. There were significant differences in age (60.9 vs. 65.0, p<0.001), and in dust expose duration (17.0 vs. 19.2, p=0.024) between two groups, but no significant difference in smoking (p=0.784). Of the 328 subjects, 13 diagnosis were extracted from 245 subjects (74.7%). Coronary artery calcification (CAC) was significantly higher in positive group than that in negative group (36.9% vs. 25.3%, p=0.049). Honeycombing showed higher frequency in positive group than in negative group (6.2% vs. 1.2%, p=0.079). Pneumoconiosis findings caused by inorganic dusts exposure showed the significant relation with CAC on LDCT images. Future studies need to prove that pneumoconiosis finding is independent risk factor for CAC using a coronary artery angiography.

• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.2
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• pp.7-11
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• 2012

Purpose : The effect of concomitant use of $^{18}F$-FDG and intravenous contrast agent (CA) on dual-energy X-ray absorptiometry (DXA), was rarely reported. We had investigated these potentially confounding effects. Materials and Methods : Twenty-two patients had undergone DXA before and immediately after $^{18}F$-FDG PET/CT scans. Two DXA and 1 PET/CT scans had performed within one-day. $^{18}F$-FDG PET/CT scans had been performed with CA in 17 patients and without CA in 5 patients. Whole body bone mineral content (BMC), whole body bone mineral density (BMD), total fat mass (TFM), and lean body mass (LBM) were measured by DXA scanner before and after the $^{18}F$-FDG PET/CT scans. Results : BMC, BMD, TFM and LBM had significantly affected by $^{18}F$-FDG PET/CT with CA (BMC, +13.7%, from $2061.3{\pm}393.7$ to $2343.4{\pm}373.3$; BMD, +9.3%, from $1.07{\pm}0.09$ to $1.17{\pm}0.08$; TFM, -34.1%, from $17052.1{\pm}4049.9$ to $11237.1{\pm}2990.3$; LBM, +13.6%, from $45834.5{\pm}5662.1$ to $52094.0{\pm}6335.4$). However, $^{18}F$-FDG PET/CT without CA had no effect on the measurement of DXA (BMC, +2.4%, from $2197.7{\pm}391.6$ to $2251.5{\pm}380.9$; BMD, +1.8%, from $1.13{\pm}0.09$ to $1.15{\pm}0.07$; TFM, -6.8%, from $14585.6{\pm}3455.9$ to $13591.3{\pm}4351.4$; LBM, +2.2%, from $47360.5{\pm}8381.8$ to $48441.1{\pm}8488.1$). Conclusion : The measurements of DXA are affected by using CA. However, DXA scans might be unaffected by the presence of $^{18}F$-FDG administered for PET/CT.

• Imaging Science in Dentistry
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• v.36 no.2
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• pp.111-116
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• 2006

PET/CT is a new imaging technology that combines high-quality Positron Emission Tomography (PET) and Computed Tomography (CT). This imaging provides simultaneous anatomical and metabolic information. Therefore PET/CT is useful diagnostic modality for early detection of malignant tumor, accurate staging, decision on therapeutic plan, monitoring response to therapy and rapid detection of recurrence. We report oral and maxillofacial cancers diagnosed by using PET/CT and the usefulness of PET/CT in the evaluation of postoperative recurrence.

• Journal of radiological science and technology
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• v.32 no.2
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• pp.195-203
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• 2009

Image registration is a fundamental task in image processing used to match two or more images. It gives new information to the radiologists by matching images from different modalities. The objective of this study is to develop 2D image registration algorithm for PET/CT and CT images acquired by different systems at different times. We matched two CT images first (one from standalone CT and the other from PET/CT) that contain affluent anatomical information. Then, we geometrically transformed PET image according to the results of transformation parameters calculated by the previous step. We have used Affine transform to match the target and reference images. For the similarity measure, mutual information was explored. Use of particle swarm algorithm optimized the performance by finding the best matched parameter set within a reasonable amount of time. The results show good agreements of the images between PET/CT and CT. We expect the proposed algorithm can be used not only for PET/CT and CT image registration but also for different multi-modality imaging systems such as SPECT/CT, MRI/PET and so on.