• The Korean Journal of Nuclear Medicine
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• v.35 no.3
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• pp.142-151
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• 2001

Purpose: This study was performed to search the relatively specific brain regions related to the semantic processing of Korean and English words on the one hand and the regions common to both on the other. Materials and Methods: Regional cerebral blood flow associated with different semantic tasks was examined using $[^{15}O]H_2O$ positron omission tomography in 13 healthy volunteers. The tasks consisted of semantic tasks for Korean words, semantic tasks for English words and control tasks using simple pictures. The regions specific and common to each language were identified by the relevant subtraction analysis using statistical parametric mapping. Results: Common to the semantic processing of both words, the activation site was observed in the fusiform gyrus, particularly the left side. In addition, activation of the left inferior temporal gyrus was found only in the semantic processing of English words. The regions specific to Korean words were observed in multiple areas, including the right primary auditory cortex; whereas the regions specific to English words were limited to the right posterior visual area. Conclusion: Internal phonological process is engaged in performing the visual semantic task for Korean words of the high proficiency, whereas visual scanning plays an important role in performing the task for English words of the low proficiency.

• Archives of Pharmacal Research
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• v.27 no.9
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• pp.961-967
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• 2004

The development of an antibody labeling method with $^{99m}$Tc is important for cancer imaging. Most bifunctional chelate methods for $^{99m}$Tc labeling of antibody incorporate a $^{99m}$Tc chelator through a linkage to lysine residue. In the present study, a novel site-specific $^{99m}$Tc labeling method at carbohydrate side chain in the Fc region of 2 antibodies (T101 and rabbit anti-human serum albumin antibody (RPAb)) using dihydrazinophthalazine (DHZ) which has 2 hydrazino groups was developed. The antibodies were oxidized with sodium periodate to pro-duce aldehyde on the Fc region. Then, one hydrazine group of DHZ was conjugated with an aldehyde group of antibody through the formation of a hydrazone. The other hydrazine group was used for labeling with $^{99m}$Tc. The number of conjugated DHZ was 1.7 per antibody. $^{99m}$Tc labeling efficiency was 46-85％ for T101 and 67∼87％ for RPAb. Indirect labeling with DHZ conjugated antibodies showed higher stability than direct labeling with reduced antibodies. High immunoreactivities were conserved for both indirectly and directly labeled antibodies. A biodistribution study found high blood activity related to directly labeled T1 01 at early time point as well as low liver activity due to indirectly labeled T101 at later time point. However, these findings do not affect practical use. No significantly different biodistribution was observed in the other organs. The research concluded that DHZ can be used as a site-specific bifunctional chelating agent for labeling antibody with $^{99m}$Tc. Moreover, $^{99m}$Tc labeled antibody via DHZ was found to have excellent chemical and biological properties for nuclear medicine imaging.edicine imaging.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.5
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• pp.443-450
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• 2009

Purpose: Conventional image reconstruction uses simplified physical models of projection. However, real physics, for example 3D reconstruction, takes too long time to process all the data in clinic and is unable in a common reconstruction machine because of the large memory for complex physical models. We suggest the realistic distributed memory model of fast-reconstruction using parallel processing on personal computers to enable large-scale technologies. Materials and Methods: The preliminary tests for the possibility on virtual manchines and various performance test on commercial super computer, Tachyon were performed. Expectation maximization algorithm with common 2D projection and realistic 3D line of response were tested. Since the process time was getting slower (max 6 times) after a certain iteration, optimization for compiler was performed to maximize the efficiency of parallelization. Results: Parallel processing of a program on multiple computers was available on Linux with MPICH and NFS. We verified that differences between parallel processed image and single processed image at the same iterations were under the significant digits of floating point number, about 6 bit. Double processors showed good efficiency (1.96 times) of parallel computing. Delay phenomenon was solved by vectorization method using SSE. Conclusion: Through the study, realistic parallel computing system in clinic was established to be able to reconstruct by plenty of memory using the realistic physical models which was impossible to simplify.

• The Korean Journal of Nuclear Medicine
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• v.27 no.2
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• pp.223-232
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• 1993

Technetium labeled isonitrile analogues are widely used as myocardial perfusion imaging agents. We synthesized and characterized a new isonitrile compound, ethyl 3-isocyanobutyrate(EIB). Proton and $^{13}C$ NMR spectroscopy and thin layer chromatography with a $C_{18}$ coat was performed. EIB was easily labeled with $^{99m}TcO_4^-$- with sodium dithionite. The labeling efficiency measured by RP-HPLC was over 95%. The labeled product was stable with dilution in normal saline and with prolonged incubation at room temperature. There was no formation of secondary products or free $^{99m}TcO_4^-$. In vivo kinetics study of $^{99m}Tc$ (I) labeled EIB in rabbits showed adequate myocardial uptake, good contrast against lung background, and relatively rapid liver clearance. The heart to lung ratio was over 2.5 and the heart to liver ratio was approximately from 0.4 to 5 at 60 minutes post injection. Hepatic clearance of $^{99m}Tc-MIBI$ was faster ($t_{1/2}$=6 minutes) than that of $^{99m}Tc-MIBI$. In vivo kinetics observed in dog was similar to that in rabbit but there was faster gallbladder filling, and thus lower liver background. SPECT imaging of the canine myocardium showed favorable imaging characteristics. However, biodistribution in mice demonstrated a myocardial % injected dose/organ of less than 0.1%. This was thought to be due to interspecies difference in plasma esterase activity. In human plasma, $^{99m}Tc$ ( I ) labeled EIB was stable for at least 2 hours, without production of secondary products by HPLC. We conclude that ethyl 3-isocyanobutyrate may be a potential new myocardial perfusion imaging agent and deserves further investigation as to its usefulness for clinical use.

• The Korean Journal of Nuclear Medicine
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• v.31 no.1
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• pp.83-89
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• 1997

About one-third of radiologically indeterminate solitary pulmonary nodules (SPN) are eventually turned out to be malignant. It is very important to noninvasively determine whether the SPN is malignant or not for the decision of its way of management. PET imaging is highlighted by its unique ability of imaging the function and metabolism of cells. Glucose metabolism is increased in malignant transformed cells. We peformed FDG-PET studies in patients who had radiologically indeterminate SPN and compared the findings with histologic diagnoses to assess the diagnostic accuracy in the detection of malignancy and to decide which parameter is the most suitable for clinical practice among peak SUV (pSUV), average SUV (aSUV), 50/10 ratio, and time-activity curve (TAC), Thirty patients were included in this study and the most useful parameter was pSUV. The sensitivity and specificity in the detection of malignant SPN using 3.5 as a cut off pSUV were both 87%. Interestingly, all 2 false-negative cases were bronch-ioloalveolar carcinoma on histologic examination. If these cases, which could be strongly suspected by CT findings, were excluded, the sensitivity of pSUV was 100%. In conclusion, PET imaging is very helpful for determining malignancy in indeterminate SPN and pSUV is a conveniently measurable parameter which is valuable for interpretation.

• The Korean Journal of Nuclear Medicine Technology
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• v.12 no.3
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• pp.176-180
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• 2008

Department of Nuclear Medicine in Seoul National University Hospital (SNUH) had developed $^{18}F$-Flumazenil as Benzodiazepine receptor imaging agent for PET diagnosis of Epilepsy. But production Activity of $^{18}F$-Flumazenil is decreased owing to this method has difficult synthesis procedures and pretty long synthesis time. In this study, we can modify synthesizing method to have more simple procedure and less spend time and help to increase production Activity. Old method: Radioactivity was produced by cyclotron was captured by QMA cartridge that was activated. Captured radioactivity was eluted into the reaction vial by using kryptofix solution and delivered. After evaporation of eluent, the azeotrophic drying step repeated two times. tosylflumazenil in anhydrous Acetonitrile was added to a reaction vial while bubbling. The reaction mixture was evaporated until the mixture volume was 0.5 mL. Reaction vial washed with 20 % Acetonitrile and that solution went into the reaction vial. The reaction mixture was loaded to the HPLC loop by hand and purified $^{18}F$-Flumazenil by HPLC column. New method: We used $TBAHCO_3$ solution as a eluent. After the eluent was evaporated, tosylflumazenil in anhydrous acetonitrile was added to a reaction vial and the reaction mixture was bubbled for 15 minutes. It was evaporated until the mixture volume became 0.5 mL. It was loaded to the HPLC loop. In old method, $^{18}F$-Flumazenil was synthesized via 6 steps synthesis procedures in 105 minutes with 30~35% synthesizing yield (non-decay correction) and specific activity was about $0.5{\sim}2{\times}10^5$ Ci/mole. In new method, It had 3 steps synthesis procedures in 53 minutes with 40~45% synthesizing yield and specific activity was about $3{\sim}8{\times}10^5$ Ci/mole. This method leads to improve of minimizing synthesis time, increasing synthesis yield and specific activity. While we can load reaction mixture to the HPLC loop, we can expose high radiation field thanks to used by hand.

• The Korean Journal of Physiology and Pharmacology
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• v.9 no.3
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• pp.137-141
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• 2005

This study was undertaken to investigate the effects of [$D-Ala^2$, D-Leu^5$]-enkephalin (DADLE) on the spontaneous activity of medial vestibular nuclear neurons of the rat. Sprague-Dawley rats, aged 14 to 16 days, were anesthetized with ether and decapitated. After enzymatic digestion, the brain stem portion of medial vestibular nuclear neuron was obtained by micropunching. The dissociated neurons were transferred to a recording chamber mounted on an inverted microscope, and spontaneous action potentials were recorded by standard patch-clamp techniques. The spontaneous action potentials were increased by DADLE in 12 cells and decreased in 3 cells. The spike frequency and resting membrane potential of these cells were increased by DADLE. The depth of afterhyperpolarization was not affected by DADLE. The potassium currents were decreased in 20 cells and increased in 5 cells. These results suggest that DADLE increases the neuronal activity of the medial vestibular nuclear neurons by altering resting membrane potential.

• Journal of Biomedical Engineering Research
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• v.26 no.1
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• pp.17-22
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• 2005

Small animal PET using a dual layer phoswich detector has been developed to obtain high and uniform spatial resolution. In this study, a simple analytic model to optimize the lengths of a dual layer phoswich detector was derived and validated by Monte Carlo simulation. For a small animal PET scanner with a 10㎝ ring diameter, the optimal length of the phoswich detector consisting of various crystal materials, such as LSO and LuYAP, were calculated analytically and validated using GATE. The detector module consisted of 8×8 arrays of crystals, with each phoswich detector element having a 2㎜×2㎜ sensitive area. The total crystal length was fixed to 20㎜. The optimal lengths of the phoswich detector layers, as functions of the crystal materials and order, conveniently derived by the analytic equation, showed good agreement with those estimated by the time consuming simulation. The simple analytical model can be used for the fast and accurate design of an optimal phoswich detector for small animal PET to achieve high spatial resolution and uniformity.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.1
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• pp.65-69
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• 2015

Background: To evaluate the impact of adding taxanes to anthracycline-based regimens in the adjuvant setting in localized young female breast cancer patients on the overall survival (OS) and the disease free survival (DFS). Materials and Methods: This retrospective study included all female breast cancer patients who were candidates for adjuvant chemotherapy presenting to Kasr Al Ainy centre of clinical oncology and Cairo oncology centre (Cairo Cure) in the period from January 2005 till December 2010. Results: Our study included 865 patients, 732 of whom received anthracycline based regimens and 133 taxane based regimens. The mean age of patients was 39 years. After a median follow up of 50 months the median DFS was 48.4 months. Survival analysis indicated that the tumor size (>5cm vs. <5cm) p=0.001), nodal involvement (Yes vs. No) p=0.0001) and pathology (invasive lobular vs. ductal) p=0.048) affected DFS. As regards hormonal status, ER, PR and HER 2neu positive patients had longer DFS (p=0.001, 0.003, 0.106). On multivariate analysis DFS was affected by tumor size and lymph node involvement (p=0.014, 0.007). Subgroup analysis showed improvement in arms treated with taxanes in terms of DFS with positive Her2neu, ER and PR, but this was not statistically significant. Conclusions: Adding adjuvant taxanes to anthracyclines is beneficial for treatment of localized breast cancer among all subgroups, especially higher risk groups. The type of adjuvant chemotherapy regimens and tumor characteristics have direct effects on DFS.

• The Korean Journal of Nuclear Medicine
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• v.9 no.1
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• pp.51-58
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• 1975

It is a great value to find an early detection of involvement of ureteric obstruction in the carcinoma of cervix. Little or no knowledge of the condition of the kidneys or the lower urinary tract are able to elucidate by the biochemical studies such as blood nitrogen or urine creatinine in carcinoma of cervix. Findings of urography delineates the condition of urinary tract stasis in the renal pelvis and ureters, however, slight stasis maybe difficult to demonstrate. On the other hand isotope nephrography is accepted as a sensitive method to observe renal function especially in regarding to the excretory function of kidney. It was attempted to analysis the findings of urography conjunction with isotope nephrography in 50 cases of unselected patients with invasive carcinoma of cervix through pre and post irradiation follow up studies. Urography was done as a routine procedure and.analysed emphasising changes of collecting systems and ureter condition. Isotope nephrography was carried out by means of $15{\mu}ci\;I^{131}$-Hippuran injected intravenously and the curves were analysed as follows. Parameter were; time of maximum amplitude ($T_{max}$), half time of maximum amplitude ($T\frac{1}{2}$), Kac and Kex value calculated from these two parameters in Tobe's method. The excretion index by Aurell defines the ratio between the maximum activity and the activity measured on the slope of the third phase ten minites after it has reached its maximum. Results: 1. 28.8% had an abnormal IVP suggestive of ureteric involvement before irradiation therapy and the patient of stage III and IV were the great part. 2. 21.7% had abnormal findings of per-irradiation renogram whom showed normal IVP. The other group showed normal IVP which group also showed normal renogram prior irradiation. 3. The more severe the ureteric involvement, the change of excretion index was greater. 4. Even in stage I and II patient, abnormal renogram was revealed in 12 cases (39.4%) among 31 cases. 5. All cases of TAH showed abnormal findings of IVP and renogram. 6. No. definite change of renogram was obtained just after the irradiation therapy (point $A:8000{\sim}9000rads,\;B:5000{\sim}6000rads,\;Co:11000{\sim}13000rads$). Each 3 month follow up study was performed and comparing with preirradiation study which showed significant changes of excretion index of renogram were 42.8% in $6{\sim}9$ month follow-up and 75% in $9{\sim}12$ month, respectively. 7. It seems to be important to observe the parameter Kex and excretion index of renogram to determine early abnormality of kidney excretory function by means of post-irradiation follow up study.