• Dementia and Neurocognitive Disorders
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• v.17 no.4
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• pp.174-175
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• 2018

• The Korean Journal of Nuclear Medicine Technology
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• v.21 no.1
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• pp.23-28
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• 2017

Purpose Recently, there has been increasing demands for clinical departments at Asan Medical center in Seoul. They want to see the results of lab tests about blood samples as soon as possible and to be reported to them on the day. As the main contents of the survey, we explained the goodness of Asan medical center's in vitro and the points to be improved. Based on this, it became an opportunity to create a positive image of In vitro laboratory. In addition, we could identify their specific requirements through the surveys. Materials and Methods In September 2016, a total of 14 questionnaire surveys were conducted for 49 clinical departments and outpatient nurses at Asan Medical center in Seoul. The survey consists of description questions to be able to express the intention of the individual and the questions made on the Likert 4 point scale. The main contents of 14 questions are composed of goodness of In Vitro laboratory and points to be improved. Results 62% answered that the best service in In Vitro laboratory was "good accuracy and reproducibility". On the other hand, as an inconvenience when requesting blood tests, 73% pointed out that "the result report time was long", which was recognized as a part to be improved. There are many contents that "The result of all tests is reported within 2 hours" on the day of the examination. In the question - 'Are there some examination results which do not coincide well with clinical observations?', 55 of 56 people answered "no". Above all, the majority answered that waiting for re-examination results is too long. This problem must be causing discomfort to the patients. Conclusion In order to improve these problems, the first thing is to increase the number of blood tests by using the current personnel, equipments and reagents to the fullest by item in Asan Medical Center's Nuclear medicine in vitro part. Secondly, in case of re-examinations, we use the "AMIS message" to show other clinical departments the reporting time. This methode improves the efficiency of work with nurses and increases satisfaction of custom service. Thirdly, the correlation was evaluated by selecting the test species that can be carried out by the shortening method. Currently, C-peptide and insulin are implemented in the reaction process to shorten 2 hours into 1 hour. Finally, we are considering purchasing new equipments for quick test results.

• The Korean Journal of Nuclear Medicine
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• v.26 no.2
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• pp.338-345
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• 1992

We evaluated the scintigraphic findings of sonographically atypical hemangioma, that is, a hypoechoic or heterogeneously hypoechoic nodule which contains hypoechoic areas more than 40% of the volume, and compared it with those of sonographically typical hemangioma in 26 patients with 31 nodules. Sonographically atypical hemangioma were 13 in 11 patients and sonographically typical hemangioma were 18 the 15 patients. Dynamic blood flow, planar and SPECT blood pool imaging was performed. In atypical hemangioma, increased blood pool activity was seen in 11 of 13 nodules on SPECT and in 10 of 13 nodules on planar image and increased blood flow was seen in 4 of 13 nodules on dynamic blood flow study. No significant difference in detecting increased blood pool activity between sonographically atypical and typical hemangioma. In conclusion, $^{99m}Tc-red$ blood cell SPECT is as useful in diagnosis of sonographically atypical hemangioma as in typical hemangioma and can be used as a confirmatory or complementary study.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.5
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• pp.451-458
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• 2009

Purpose: Optical molecular luminescence imaging is widely used for detection and imaging of bio-photons emitted by luminescent luciferase activation. The measured photons in this method provide the degree of molecular alteration or cell numbers with the advantage of high signal-to-noise ratio. To extract useful information from the measured results, the analysis based on a proper quantification method is necessary. In this research, we propose a quantification method presenting linear response of measured light signal to measurement time. Materials and Methods: We detected the luminescence signal by using lab-made optical imaging equipment of animal light imaging system (ALIS) and different two kinds of light sources. One is three bacterial light-emitting sources containing different number of bacteria. The other is three different non-bacterial light sources emitting very weak light. By using the concept of the candela and the flux, we could derive simplified linear quantification formula. After experimentally measuring light intensity, the data was processed with the proposed quantification function. Results: We could obtain linear response of photon counts to measurement time by applying the pre-determined quantification function. The ratio of the re-calculated photon counts and measurement time present a constant value although different light source was applied. Conclusion: The quantification function for linear response could be applicable to the standard quantification process. The proposed method could be used for the exact quantitative analysis in various light imaging equipments with presenting linear response behavior of constant light emitting sources to measurement time.

• The Korean Journal of Nuclear Medicine
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• v.28 no.1
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• pp.44-51
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• 1994

It is known that the normal His-Purkinje system provides for nearly synchronous activation of right (RV) and left (LV) ventricles. When His-Purkinje conduction is abnormal, the resulting sequence of ventricular contraction must be correspondingly abnormal. These abnormal mechanical consequences were difficult to demonstrate because of the complexity and the rapidity of it's events. To determine the relationship of the phase changes and the abnormalities of ventricular conduction, we performed phase image analysis of $^{99m}Tc$-RBC gated blood pool scintigrams in patients with intraventricular conduction disturbances (24 complete left bundle branch block (C-LBBB), 15 complete right bundle branch block (C-RBBB), 13 Wolff-Parkinson-White syndrome (WPW), 10 controls). The results were as follows; 1) The ejection fraction (EF), peak ejection rate (PER), and peak filling rate (PFR) of LV in gated blood pool scintigraphy (GBPS) were significantly lower in patients with C-LBBB than in controls ($44.4{\pm}13.9%$ vs $69.9{\pm}4.2%,\;2.48{\pm}0.98$ vs $3.51{\pm}0.62,\;1.76{\pm}0.71$ vs $3.38{\pm}0.92$, respectively, p<0.05). 2) In the phase angle analysis of LV, Standard deviation (SD), width of half maximum of phase angle (FWHM), and range of phase angle were significantly increased in patients with C-LBBB than in controls ($20.6{\pm}18.1$ vs $8.6{\pm}1.8,\;22.5{\pm}9.2$ vs $16.0{\pm}3.9,\;95.7{\pm}31.7$ vs $51.3{\pm}5.4$, respectively, p<0.05). 3) There was no significant difference in EF, PER, PFR between patients with the Wolff-parkinson-White syndrome and controls. 4) Standard deviation and range of phase angle were significantly higher in patients with WPW syndrome than in controls ($10.6{\pm}2.6$ vs $8.6{\pm}1.8$, p<0.05, $69.8{\pm}11.7$ vs $51.3{\pm}5.4$, p<0.001, respectively), however, there was no difference between the two groups in full width of half maximum. 5) Phase image analysis revealed relatively uniform phase across the both ventricles in patients with normal conduction, but markedly delayed phase in the left ventricle of patients with LBBB. 6) In 13 cases of WPW syndrome, the site of preexcitation could be localized in 10 cases (77%) by phase image analysis. Therefore, it can be concluded that phase image analysis can provide an accurate noninvasive method to detect the mechanical consequences of a wide variety of abnormal electrical activation in ventricles.

• The Korean Journal of Nuclear Medicine
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• v.38 no.1
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• pp.74-84
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• 2004

Purpose: Since I-125 emits low energy (27-35 keV) radiation, thinner crystal and collimator could be employed and, hence, it is favorable to obtain high quality images. The purpose of this study was to derive the optimized parameters of I-125 SPECT using a new simulation tool, GATE (Geant4 Application for Tomographic Emission). Materials and Methods: To validate the simulation method, gamma camera developed by Weisenberger et al. was modeled. Nal(T1) plate crystal was used and its thickness was determined by calculating detection efficiency. Spatial resolution and sensitivity curves were estimated by changing variable parameters for parallel-hole and pinhole collimator. Peformances of I-125 SPECT equipped with the optimal collimator were also estimated. Results: in the validation study, simulations were found to agree well with experimental measurements in spatial resolution (4%) and sensitivity (3%). In order to acquire 98% gamma ray detection efficiency, Nal(T1) thickness was determined to be 1 mm. Hole diameter (mm), length (mm) and shape were chosen to be 0.2:5:square and 0.5:10:hexagonal for high resolution (HR) and general purpose (GP) parallel-hole collimator, respectively. Hole diameter, channel height and acceptance angle of pinhole (PH) collimator were determined to be 0.25 mm, 0.1 mm and 90 degree. The spatial resolutions of reconstructed image of the I-125 SPECT employing HR:GP:PH were 1.2:1.7:0.8 mm. The sensitivities of HR:GP:PH were 39.7:71.9:5.5 cps/MBq. Conclusion: The optimal crystal and collimator parameters for I-125 Imaging were derived by simulation using GATE. The results indicate that excellent resolution and sensitivity imaging is feasible using I-125 SPECT.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.1
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• pp.52-60
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• 2008

Purpose: To establish the methods for sinogram formation and correction in order to appropriately apply the filtered backprojection (FBP) reconstruction algorithm to the data acquired using PET scanner with multiple scintillation crystal layers. Materials and Methods: Formation for raw PET data storage and conversion methods from listmode data to histogram and sinogram were optimized. To solve the various problems occurred while the raw histogram was converted into sinogram, optimal sampling strategy and sampling efficiency correction method were investigated. Gap compensation methods that is unique in this system were also investigated. All the sinogram data were reconstructed using 20 filtered backprojection algorithm and compared to estimate the improvements by the correction algorithms. Results: Optimal radial sampling interval and number of angular samples in terms of the sampling theorem and sampling efficiency correction algorithm were pitch/2 and 120, respectively. By applying the sampling efficiency correction and gap compensation, artifacts and background noise on the reconstructed image could be reduced. Conclusion: Conversion method from the histogram to sinogram was investigated for the FBP reconstruction of data acquired using multiple scintillation crystal layers. This method will be useful for the fast 20 reconstruction of multiple crystal layer PET data.

• The Korean Journal of Nuclear Medicine
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• v.26 no.1
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• pp.111-115
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• 1992

Miliary Tuberculosis is an illness produced by acute dissemination of tubercle bacilli via the blood stream. In chest roentgenogram, a diffuse "miliary" infiltrates are usually seen, but normal or suspicious ground glass pattern also can be seen in early manifestation. Ten patients of miliary tuberculosis who underwent whole-body $^{67}Ga-citrate$ scintigraphy were evaluated retrospectively to study usefulness of Ga-scan for early diagnosis of miliary Tbc and evaluation of disease activity. All of ten patients demonstrated significantly diffuse bilateral pulmonary uptakes on 48 hours image. All of three patients of ground-glass pattern in chest roentgemogram also demonstrated increased uptakes. In the statistical analysis, the severity of chest roentgenographic findings showed positive correlation with the activity on Ga?scan. These results suggest that Gallium scan is useful for diagnosis of early miliary tuberculosis and for evaluation of disease activity on follow-up examination of miliary tuberculosis of lung.

• The Korean Journal of Cytopathology
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• v.17 no.2
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• pp.116-119
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• 2006

The diagnosis of papillary thyroid cancer is generally based on the findings of intranuclear cytoplasmic inclusions and nuclear grooves. Although anisokaryosis and poikilokaryosis, in papillary thyroid cancer, are not distinct when compared to other cancers, cytological examination can provide useful preoperative information. Our study evaluated the diagnostic role of computer-assisted image analysis for the pre-surgical assessment of papillary thyroid carcinoma. Thyroid aspirates from twenty female patients who were histologically confirmed to have both papillary carcinoma and benign nodules were studied. Different populations of 50 benign cells and 50 malignant cells were analyzed. Five morphometric parameters were selected for analysis: nuclear area, perimeter, maximum length, maximum width and intensity standard variation. The values obtained for papillary carcinomas were higher than the surrounding benign nodules as follows: nuclear area 63.5 vs. 36.1 (p=0.000), nuclear perimeter were 29.4 vs. 22.0 (p=0.000), maximum length 9.6 vs. 7.1 (p=0.000), maximum width 8.2 vs. 6.3 (p=0.000), the ratio between maximal length and maximal width 1.16 vs. 1.13 (p=0.000), the standard variation of intensity 14.9 vs. 15.9 (p=0.101) respectively. Therefore, morphometric information can be helpful for the differential cytological diagnosis of papillary thyroid carcinoma.

• Nuclear Engineering and Technology
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• v.54 no.9
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• pp.3403-3414
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• 2022

The purpose of this study is to model and optimize the block-matching and 3D filtering (BM3D) algorithm and to evaluate its applicability in brain single-photon emission computed tomography (SPECT) images using a fan beam collimator. For quantitative evaluation of the noise level, the coefficient of variation (COV) and contrast-to-noise ratio (CNR) were used, and finally, a no-reference-based evaluation parameter was used for optimization of the BM3D algorithm in the brain SPECT images. As a result, optimized results were derived when the sigma values of the BM3D algorithm were 0.15, 0.2, and 0.25 in brain SPECT images acquired for 5, 10, and 15 s, respectively. In addition, when the sigma value of the optimized BM3D algorithm was applied, superior results were obtained compared with conventional filtering methods. In particular, we confirmed that the COV and CNR of the images obtained using the BM3D algorithm were improved by 2.40 and 2.33 times, respectively, compared with the original image. In conclusion, the usefulness of the optimized BM3D algorithm in brain SPECT images using a fan beam collimator has been proven, and based on the results, it is expected that its application in various nuclear medicine examinations will be possible.