• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.1
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• pp.34-37
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• 2012

Purpose: To verify the optimal scan time per bed for clinical application, we evaluated the quality of $^{18}F$-FDG images with varying scan times in a phantom and 20 patients with 38 lesions using a Philips (TOF) PET/CT scanner. Materials and Methods: The PET/CT images of a NEMA IEC body phantom and 20 patients (16 males, 4 females) were acquired for 5 different scan times of 20-100 sec per bed with intervals of 20 sec. The activity ratio of hot spheres (diameter of 17 [H1], 22 [H2] and 28 [H3] mm) to the background region in the IEC body phantom was 8-to-1. The contrast recovery coefficient (CRC) and standard uptake value (SUV) based on ROIs of hot spheres and background region were calculated. The noise in each background region was estimated as the ratio of SD of counts to the mean counts in the background region. On the patient image, the injected dose of $^{18}F$-FDG was $444{\pm}74$ MBq and the SUVs in the 38 hot lesions were measured. Results: The two scan time groups (LT-60 [<60 sec] and GT-60 [${\geq}60$ sec]) were compared. In the phantom study, the coefficient of deviations (CVs, %) of CRC and SUV in LT-60 (H1: 14.2 and 7.3, H2: 11.4 and 7.8, H3: 4.9 and 3.2) were higher than GT-60 (H1: 8.9 and 2.8, H1: 8.2 and 5.0, H3: 2.0 and 1.6). In the patient study, the mean CV of CRC and SUV in LT-60 (4.0) was higher than GT-60 (1.2). Conclusion: This study showed that noise increased as the scan time decreased. High noise for the scan time <60 sec per bed yielded high variation of SUV and CRC. Therefore, considering PET/CT image quality, the scan time per bed in the TOF PET/CT scanner should be at least ${\geq}60$ sec.

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.396-412
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• 1997

The purpose of this study is to observe the corrosion characteristics of five dental amalgams(CAULK FINE CUT, OPTALLOY II, DISPERSALLOY, TYTIN, and VALIANT) in the solutions with fluoride compound through the anodic polarization curve obtained by using a potentiostat. After each amalgam alloy and Hg being triturated, the triturated mass was inserted into the cylindrical metal mold, and condensed by hydraulic pressure(160 kg/$cm^2$). Each specimen was removed from the metal mold. Specimens were polished with the silicone carbide grinding paper 24 hours after condensation and stored at room temperature for 1 week. The anodic polarization curves were employed to compare the corrosion behaviours of the amalgams in 0.9 % saline solution and in the saline solutions with 2.2 ppm, 0.05 %, 2 % NaF, and 8 % $SnF_2$ at $37^{\circ}C$ with 3-electrode potentiostat. After the immersion of specimen in electrolyte for 30 minutes, the potential scan was begun. The potential scan range was -1500m V to + 800m V(vs. S.C.E.) in the working electrode and the scan rate was 50 mV/sec. The results were as follows, 1. The corrosion potential, the potential of anodic current peak, and transpassive potential in the saline solutions with NaF shifted to lower direction than those in normal saline solution, and the current density in the saline solutions with NaF was higher than that in normal saline solution. The differences were increased as the concentrations of NaF became higher. 2. The corrosion potential and transpassive potential in the saline solution with $SnF_2$ shifted to higher direction than those in normal saline solution, and the current density in the saline solution with $SnF_2$ was higher than that in normal saline solution after the corrosion potential. The anodic polarization curves in the saline solution with $SnF_2$ had no outstanding anodic current peak. 3. The corrosion potentials for high-copper amalgams were much higher than those for CAULK FINE CUT and OPTALLOY II in normal saline solution, but, as the concentrations of fluoride compound became higher, the differences in corrosion potentials between them were decreased. The corrosion potentials had the similarity in the saline solution with 2% NaF or 8% $SnF_2$. 4. The current density for TYTIN was the lowest among the others in normal saline solution and in the saline solution with 2.2 ppm or 0.05 % NaF. 5. There was no significant difference in current density between Pd-enriched VALIANT and other high-copper amalgams.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.9 no.1
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• pp.17-21
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• 2023

In this study, we evaluated the targeting of prostate cancer (PCa) using [¹⁸F]Florastamin in non-clinical study, for the purpose of therapeutic monitoring of [¹⁷⁷Lu]Ludotadipep, a therapeutic radiopharmaceutical for PCa, [¹⁸F]Florastamin/[¹⁷⁷Lu]Ludotadipep was co-administered to a single-individual prostate tumor bearing mouse model, mimicking clinical condition. Considering the difference in half-life of the two isotopes (¹⁸F or ¹⁷⁷Lu), image scan of whole-body autoradiography was performed at 24 or 48 h after preparation of frozen section, respectively. Then, it was confirmed whether they showed the same targeting efficiency for the area of tumor. A tumor xenograft model was prepared using PSMA-overexpressing PC3-PIP prostate cancer cells. [¹⁸F]Florastamin [111 MBq (3 mCi) in 100 µL]/¹⁷⁷Lu]Ludotadipep [3.7 MBq (100 µCi) in 100 µL] was co-administered through the tail vein, and 2 hours after administration, the mice were frozen, and after freezing for 24 hours, whole-body cryosection was performed at 24 h after freezing. Image scanning using cryosection was performed after 24 or 48 hours after freezing, respectively. In the scan image after 24 hours, tumor uptake of [¹⁸F] Florastamin/[¹⁷⁷Lu]Ludotadipep were simultaneously observed specific uptake in the tumor. In the scan image after 48 hours in the same section, signal of ¹⁸F was lost by decay of radioisotope, and specific uptake image for [¹⁷⁷Lu]Ludotadipep was observed in the tumor. Uptake of [¹⁷⁷Lu]Ludotadipep was specific to the same tumor region where [¹⁸F]Florastamin/[¹⁷⁷Lu]Ludotadipep was uptake. These results suggested that [¹⁸F]Florastamin showed the same tumor uptake efficiency to PCa as [¹⁷⁷Lu]Ludotadipep, and effective therapeutic monitoring is expected to be enable using [¹⁸F]Florastamin during [¹⁷⁷Lu]Ludotadipep therapy for PCa.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.2958-2965
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• 2013

Purpose : To evaluate the degree of malignancy of incident thyroid lesion found in 18F-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 25 patients(1 exception) who were admitted in E hospital to receive 18F-FDG PET/CT examination until Janaary and April of 2008. 18F-FDG PET/CT image photographing was taken in Biograph-Duo made by SIEMENS, after taking normal 18F-FDG PET/CT image(1hr) and then 1hr later we took the thyroid 1 bed-delayed image for the patients who showed abnormal thyroid 18F-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, 1hr later, we took a 1 bed-delayed image and then made a comparative study between measured maxSUV of 1hr-abnormal uptake image and that of 2hr-delayed image. Results : In this 18F-FDG PET/CT study among the patients who showed incidental 18F-FDG thyroidal uptake the number of thyroid cancer was 5(20.8%), all of then showed benign findings. a comparison of results for 18F-FDG PET/CT. the benign patient measured maxSUV in the PET/CT. image(1hr) mean value 5.06maxSUV and delay image(2hr) mean value 5.23maxSUV differences of two value is 0.19maxSUV and the malignantIt patient measured maxSUV in the PET/CT. image(1hr) mean value 9.63maxSUV and delay image(2hr) mean value 10.65maxSUV differences of two value is 10.65maxSUV in Thyroid abnormal uptake patients. Conclusion : in the case of incidental 18F-FDG uptake in thyroid, max SUV of focal thyroid lesion is above 5.0 if 18F-FDG PET/CT examine the delayed images to add, You could see that reasonable diagnostic method useful. to differentiate whether lesions of malignant.

• Korean Chemical Engineering Research
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• v.47 no.1
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• pp.11-16
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• 2009

Composite electrodes for redox supercapacitor were prepared potentiodynamically by the deposition of $RuO_2$ and the co-deposition of Ru-Co mixed oxide on the surface of single-walled carbon nanotube. Electrode of Ru-Co mixed oxide, in which Ru(13.13 wt%) and Co(2.89 wt%) were deposited on the carbon nanotube, exhibited a similar specific capacitance(${\sim}620\;F\;g^{-1}$) with $RuO_2$ electrode at a low potential scan rate($10\;mV\;s^{-1}$), but showed a superior one ($570\;F\;g^{-1}$) at a high scan rate($500\;mV\;s^{-1}$) than that of $RuO_2$($475\;F\;g^{-1}$). Such increase in the specific capacitance at high scan rate by the co-deposition of Ru and Co species was due to the structural support of Co species to provide the electronic conduction through Ru species.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.4
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• pp.361-362
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• 2009

We present a patient with high $^{18}$F-fluorodeoxyglucose (FDG) uptake detected in a neurofibroma that was confused with sarcomatous transformation on a positron emission tomography/computed tomography (PET/CT) scan. A 39-year-old male patient with a 20-year history of neurofibromatosis-1 (NF-1) performed FDG PET/CT scan for the evaluation of lesions with sarcomatous transformation. The FDG PET/CT images demonstrated varying degrees of increased FDG uptake in the multiple nodules throughout whole body. The left pelvic mass with the highest FDG uptake had a maximum standardized uptake values (maxSUV) 5.0 and surgical resection was performed. Histological analysis confirmed the presence of a benign neurofibroma infiltrated with inflammatory cells.

• Childhood Kidney Diseases
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• v.26 no.1
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• pp.52-57
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• 2022

Purpose: To determine predictive factors for detecting renal parenchymal damages (RPDs) in infants with recurrent febrile urinary tract infection (fUTI). Methods: From January 2015 to December 2021, 102 infants with recurrent fUTI and who underwent ^99mTc-dimercaptosuccinic acid (DMSA) renal scan in our hospital were included in this study. Controls included infants with normal DMSA results performed 3 months apart from the 2nd episode of fUTI. DMSA-positive group included infants with positive DMSA results performed 3 months apart from the 2nd episode of fUTI or at the 3rd episode of fUTI. The recurrence rate, causative bacteria, renal size discrepancy of both kidneys, and laboratory findings including C-reactive protein (CRP) and spot urine sodium-to-potassium ratio (uNa/K) were compared between both groups. Results: Only 3.8% of 79 infants with a 2nd episode of fUTI showed positive DMSA results. fUTI recurred more frequently within 12 months of follow-up in the DMSA-positive group than in the control group (69% vs. 13%, P<0.001). CRP values were significantly higher in the DMSA-positive group than in the control group (7.3 mg/dL vs. 3.7 mg/dL, P<0.001). Spot uNa/K were significantly lower in the DMSA-positive group than in the control group (0.6 vs. 1.1, P<0.001). Conclusions: Congenital renal scar and RPDs on the DMSA scan were more frequently found in infants with recurrent fUTI than those in the control group. High CRP values and low spot uNa/K in acute infections were helpful in predicting the presence of RPD in infants with recurrent fUTI.

• Korean Journal of Optics and Photonics
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• v.11 no.2
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• pp.73-79
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• 2000

We measure a beam diameter of scan and sub-scan direction of LSD (Laser Scanning Urnt) which uses $fheta$ lens produced by injecLion molding method as a scanning lens. While the measured beam diameter in scan direction, which is $62muextrm{m}$ to $68\mu\textrm{m}$, shows similar size comparing to the design beam diameter, the sub-scan beam diameter shows sIzable beam diameter deviation as much as 37 11m ranging from $78\mu\textrm{m}$ to $115\mu\textrm{m}$. Injection molding lens has the surface figure error due to the shrinkage III the cooling time and the internal distortion (birefringence) due to the uneven cooling conditIOn so that these bring about wavefront aberration (i.e., the enlargement of beam size), and are eventually expre~sed as the deterioration of the pdnting image. In this paper. we first measure and analyze beam diameter, birefringence (polanzation ratio), and asphedcal figure error of mIens in order to know the principle cause of the beam diameter deviation in sub-scan directIOn. And Lhen. through the analysis of a designed depth of focus and a calculated field curvature (imaging position of the optical axis directIon) using the above figure elTor data, we know Lhat the birefringence IS the main factor of sizable beam diameter deVIation in sub-scan direction. ction.

• Journal of Electrochemical Science and Technology
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• v.3 no.2
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• pp.80-84
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• 2012

The polyaniline (PANI) electrodes are prepared by chemical synthesis and electrodeposition methods and their supercapacitive properties are characterized and compared by morphology observation, cyclic voltammetry as a function of scan rate, and impedance spectra analysis. In particular, the supercapacitive properties obtained in the range of higher potential scan rates (e.g., over $200mV\;s^{-1}$) are emphasized to be capable of utilizing adequately the high power capability of supercapacitor. As a result, the PANI electrode by the electrodeposition shows superior specific capacitance (max. $474F\;g^{-1}$ at $10mV\;s^{-1}$ and about $390F\;g^{-1}$ at $500mV\;s^{-1}$) than those by the chemical synthesis method. This is mainly due to highly porous structure obtained by the electrodeposition to yield higher specific surface area.

• Journal of Electrochemical Science and Technology
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• v.11 no.4
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• pp.406-410
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• 2020

Despite a simple preparation of manganese oxide (MnO₂) nanowires by electrodeposition, the improvement in specific capacitance (C_sp) and voltammetric response of the MnO₂ nanowire-based electrodes has been quite limited. This is attributed to the poor electrical conductivity of MnO₂ and its dense bulk morphology due to the aggregation of the nanowires. This study investigated the capacitive performance of MnO₂ nanowires electrodeposited on agarose thin films. The good ionic conductivity and porous network of the agarose film provided favorable growth conditions for the MnO₂ nanowires with suppressed aggregation. A maximum C_sp value of 686 F/g measured at a scan rate of 10 mV/s was obtained, which was significantly larger than that of 314 F/g for the agarose-free MnO₂ electrode at the same scan rate. The rate capability was also improved. The C_sp measured at a high scan rate of 100 mV/s retained 74.0% of the value measured at 10 mV/s, superior to the retention of 71.1% for the agarose-free MnO₂ electrode.