• Nuclear Medicine and Molecular Imaging
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• v.40 no.5
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• pp.249-256
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• 2006

Purpose: Although computed tomography (CT) is widely used for diagnosing liver metastasis from colorectal cancer, diagnostic accuracy of CT is not satisfactory. Magnetic resonance (MR) imaging and F-18 FDG PET has been reported to be superior to CT. However, studies on direct comparison of PET and MR are scarce. We compared the diagnostic accuracy of FDG PET and MR in detecting liver metastasis from colorectal cancer. Materials and Methods: Among 363 colorectal cancer patients who underwent F-18 FDG PET (ECAT, Siemens-CTI, Knoxville; Gemini, Philips, Milpitas, U.S.), 26 patients (M:F=17:9, age=$62{\pm}11$) underwent MR to evaluate suspicious metastatic liver lesions. Finally, 35 liver lesions detected by CT from 26 patients were enrolled for analysis. PET and MR results were compared with pathologic reports, clinical findings or follow-up results. Results: Of the 35 lesions, 18 lesions (51.4%) were diagnosed as liver metastases, while remaining 17 (48.6%) as benign. The sensitivity and the specificity of PET were 94.4% and 94.1%, respectively, compared to 100% and 82.4% for MR. MR and PET was concordant in 30 lesions (85.7%: 17 metastatic (94.4%) and 13 benign (76.5%) lesions. ROC curve analysis revealed maximal SUV of 3.1 as the optimum standard in differentiating metastatic from benign liver lesions (AUC=0.897, p<0.001, sensitivity 83.3%, specificity 94.1%). For small lesions less than 1 cm ln diameter (n=20), diagnostic accuracy of PET was comparable to that of MR. Conclusion: F-18 FDG PET showed good diagnostic performance in detecting liver metastasis from colorectal cancer, which was comparable to MR.

• The Korean Journal of Nuclear Medicine
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• v.28 no.3
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• pp.282-292
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• 1994

Brain perfusion SPECT shows typical regional perfusion abnormalities in Alzheimer's disease(AD) and is useful for its diagnosis. However, there is also arguement that these patterns show significant overlap with other causes, and the accuracy for SPECT in differentiating AD has shown conflicting results. We postulate that the variation in re-ported results are partly due to a difference in patient or control selection with special reference to the mixture of ischemic cerebral disease in the studied population. To deter-mine the effect of ischemic lesions and the nature of control subjects on SPECT studies for AD, we performed $^{99m}Tc$-HMPAO single photon emission computed tomography (SPECT) in 11 probable AD patients with a low (<4) Hachinski ischemic score and 12 non-demented age matched controls. Magnetic resonance imaging(MRI) disclosed ischemic cerebral lesions in 27% (3/11) of the PAD group and 25% (3/12) of the control group. Regional perfusion indices were quantitated from the SPECT images as follows and the distribution of perfusion indices from both groups were compared. This was repeated with controls after excluding those with significant ischemic lesions by MRI : regional perfusion index = average regional count/average cerebellar count All PAD patients showed perfusion abnormality in SPECT. However, 53% (10/12) of controls also showed perfusion at-normalities, and no pattern could reliably differentiate the two groups. After excluding controls with significant cerebral ischemia, the difference in temporal and parietal perfusion index was increased. A decreased tempore-parietal and any parietal or temporal per-fusion index had a sensitivity of 18% and 36% in detecting AD, respectively. When using a separate group of normal age mathced controls, the indices showed an even more difference in the temporal and parietal lobes and the sensitivity of a decreased tempore-parietal and any parietal or temporal perfusion index had a sensitivity of 36% and 55% in detecting AD, respectively. Thus, the type of control with special reference to the pres-once of ischemic cerebral lesions contribute significantly to the accuracy of perfusion SPECT in diagnosing AD. This nay have particular importance in the diagnosis of AD in populations where the prevalance of cerebrovascular disease is high.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.1
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• pp.42-48
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• 2007

Purpose: The purpose of this study is to image metastaic lung melanoma model with optimal pre-conditions for animal handling by using $[^{18}F]FDG$ small animal PET and clinical CT. Materials and Methods: The pre-conditions for lung region tumor imaging were 16-22 h fasting and warming temperature at $30^{\circ}C$. Small animal PET image was obtained at 60 min postinjection of 7.4 MBq $[^{18}F]FDG$ and compared pattern of $[^{18}F]FDG$ uptake and glucose standard uptake value (SUVG) of lung region between Ketamine/Xylazine (Ke/Xy) and Isoflurane (Iso) anesthetized group in normal mice. Metastasis tumor mouse model to lung was established by intravenous injection of B16-F10 cells in C57BL/6 mice. In lung metastasis tumor model, $[^{18}F]FDG$ image was obtained and fused with anatomical clinical CT image. Results: Average blood glucose concentration in normal mice were $128.0{\pm}23.87$ and $86.0{\pm}21.65\;mg/dL$ in Ke/Xy group and Iso group, respectively. Ke/Xy group showed 1.5 fold higher blood glucose concentration than Iso group. Lung to Background ratio (L/B) in SUVG image was $8.6{\pm}0.48$ and $12.1{\pm}0.63$ in Ke/Xy group and Iso group, respectively. In tumor detection in lung region, $[^{18}F]FDG$ image of Iso group was better than that of Ke/Xy group, because of high L/B ratio. Metastatic tumor location in $[^{18}F]FDG$ small animal PET image was confirmed by fusion image using clinical CT. Conclusion: Tumor imaging in small animal lung region with $[^{18}F]FDG$ small animal PET should be considered pre-conditions which fasting, warming and an anesthesia during $[^{18}F]FDG$ uptake. Fused imaging with small animal PET and CT image could be useful for the detection of metastatic tumor in lung region.

• The Korean Journal of Mycology
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• v.21 no.3
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• pp.200-211
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• 1993

Somatic hybrids of Pleurotus florida ASI 2016 and Pleurotus ostreatus ASI 2018 were obtained by protoplast fusion. The 40 fusants($P1{\sim}P40$) was examined for the yield on fermented and pasteurized rice straw in a tray. The carpophore yield of them were showed as the range of $27.0{\sim}155.2$, based on parental values of 100(ASI 2018), The pilei of fusants between orange white colored P. florida and dark grey colored P. ostreatus had mixed colors in the young stage. Other breeding programmes were performed to improve new varieties with high yield and good quality. A new oyster mushroom variety, Wonhyeongneutaribeosus(P72), was developed at the Agricultural Sciences Institute, Rural Development Administration in 1990. This P.florida-ostreatus-ostreatus hybrid P72 was selected from 38 protoplast fusion products($P41{\sim}P78$) between P.florida-ostreatus recombinant P5-M 43-arg rib and P. ostreatus ASI 2-13-0 2001-19-pro orn. The yield indexes of 38 hybrids ranged $40.5{\sim}152.7$ compared with the parental values of 100(ASI 2001). Hybrid P72 was characterized by the large fruiting bundle of semispherical shape with long stipe and by the small and circular pileus, resulting in lower harvesting cost. A significant increase in carpophore production was observed in somatic hybrids of protoplasts due to heterosis. A comparision of hybrid with parents P72 was made using isozyme analysis. The esterase banding patterns could be characterized by new bands in the hybrids. Seven fusion products of four crosses between P.florida ASI 2016 and P. ostreatus ASI 2018 were analysed with respect to the distribution of progenies and segregation of gene markers by random basidiospore analysis. Segregation of alleles should yield progeny of four genotypes in a Mendelian ratio of 1 : 1 : 1 : 1 for prototrophs, auxotrophs of one parental type, auxotrophs of the other parental type, and auxotrophic recombinants, respectively. However, five fusants of them did not detect one parental, P.ostreatus, type. Basidiospores could yield progeny of 16 genotypes in the cross of one of the recombinant P5-M43-arg $rib{\times}P. ostreatus$ ASI 2-13-pro orn but the segregants of three fusants were not detected clearly. The allele ratio of loci could be expected 1 : 1 : 1 : 1 for arg, rib, pro and orn. The ratio, however, would be changed to 4 : 1 : 1 : 1 with increasing proportion of argo In almost all the fusants, prototrophic recombinants were recovered in large numbers against auxotrophic markers. Parental genotypes were recovered with the recombinant progeny amounting to $38.68{\sim}99.56%$. The analysis provides proof of heterokaryosis and strong evidence for haploidy of vegetative nuclei, a sexual cycle consisting of nuclear fusion and meiosis.

• Journal of radiological science and technology
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• v.30 no.4
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• pp.313-320
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• 2007

There are the Medical Radiation Health and Safety Act(the Patient Radiation Health and Safety Act, the Radiologic Technologist Act), the Medical Laboratory Technologist Act, the Physical Therapy Practice Act, and the Dental Hygienist Act, etc in America. However, Korea has only one Act for a medical radiologic technologist(including radiation therapy technologist, nuclear medicine technologist), medical laboratory technologist, physical therapist, occupational therapy examiner, dental hygienist, and so on. It is the Medical Technologist Act. Therefore, the Medical Radiation Health and Safety Act for a radiologic technologist(including radiation therapy technologist, nuclear medicine technologist) has to be enacted independently in Korea. It is the purpose of this Act to provide for the appropriate certification of persons using radioactive materials, equipment emitting ionizing radiation on humans or performing medical imaging for diagnostic and therapeutic purposes. In Korea, the radiologic technologist is a "fusion technologist" who is a person other than a licensed practitioner as a radiographer, radiation therapist, nuclear medicine technologist, computed tomography technologist, magnetic resonance technologist, mammographer, sonographer, medical dosimetrist, quality management technologist, etc. This Act will have some provisions related to the definitions, reserved title, scope of practice, specialized technologist, application for licensure, radiologic technology council, renewal, continuing education, the radiation control advisory commission, etc. This Act will ensure that quality radiation therapy treatments are delivered and that quality diagnostic information is presented for interpretation, which will lead to accurate diagnosis, treatment and cure. Accurate diagnosis can be provided only when a personnel is properly educated in technique, equipment operation and radiation safety. In the end, this Act will protect the civil right to health. By regulating the personnel responsible for performing those procedures, this Act will mean improved care for patients-higher quality images, improved accuracy, and less exposure to radiation.

• Journal of Embryo Transfer
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• v.28 no.3
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• pp.229-235
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• 2013

The objective of this study was to monitor health conditions of four genetically identical somatic cells cloned Labrador retriever puppies by estimation of body weight and analysis of hematologic and serologic characteristics. Naturally ovulated oocytes and donor cells were used for somatic cell nuclear transfer (SCNT). Donor cells and enucleated oocytes were followed by electric fusion, chemical activation and surgical embryo transfer into the oviducts of surrogate females. Two recipients became pregnant; two maintained pregnancy to term, and four live puppies were delivered by Caesarean section. The cloned Labrador retrievers were genetically identical to the nuclear donor dog. The body weight of clone-1, -2, -3, and -4 was increased from 0.66, 0.40, 0.39, and 0.37 kg at birth to 6.2, 6.6, 6.2, and 6.0 kg at 8 weeks of age, respectively. Although clone-4 had lower numbers of RBC than reference range, the most of RBC and WBC related heamatologic results of cloned puppies were not different when compared to reference range. In serological analysis, Glucose, ALP and inorganic phosphate level of four cloned puppies was significantly higher than the reference ranges. However, there was no significant difference among four cloned dogs. This study suggests that cloned puppies derived from SCNT did not have remarkable health problems, at least in the growth pattern and hematological and serological parameters.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.4
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• pp.487-495
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• 2007

The objectives of the present study were to initiate cloning of Korean native goat by somatic cell nuclear transfer (NT) and to examine whether unovulated (follicular) oocytes can support the same developmental ability of NT embryos as ovulated (oviductal) oocytes after hCG injection in stimulated cycles of the goat. The in vivo-matured and immature oocytes were collected from the oviducts and follicles of superovulated does, respectively, and the immature oocytes were maturated in vitro. Ear skin fibroblasts derived from a 3-yr-old female Korean native goat were used as the donors of nuclei or karyoplasts. Following fusion, activation and in vitro culture to a 2- to 4-cell stage, 49 in vitro-derived and 105 in vivo-derived embryos were transferred to 6 and 17 recipient does, respectively. One doe and three does of the respective groups were identified as pregnant by ultrasonography on day 30 after embryo transfer. However, only one doe, which had received in vivo-derived embryos, delivered a normal female kid of 1.9 kg on d 149. The cloned kid gained more weight than her age-matched females as much as 87% during the first 4 mo after birth (17.7 vs. $9.4{\pm}0.8$ kg) and reached puberty at 6-mo age a few months earlier than normal female does. The telomere length of the kid, which was similar to that of the donor fibroblast at 2-mo age, decreased 8% between 2- and 7-mo ages. Moreover, at 7-mo age, she had 21% shorter telomere than her age-matched goats. To our knowledge, this is the first case in which a cloned animal born with a normal weight exhibited accelerated growth and development. The unusually rapid growth and development of the cloned goat may have resulted from SCNT-associated epigenetic reprogramming involving telomere shortening.

• Reproductive and Developmental Biology
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• v.36 no.2
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• pp.115-120
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• 2012

This study was conducted to examine the optimal concentration and treatment time of antioxidants for inhibition of the ROS generation in bovine somatic cell nuclear transfer (SCNT) embryos. Bovine oocytes were activated parthenogenetically, during which oocytes were treated with various antioxidants to determine the optimal concentrations and kind of antioxidants. Determined antioxidants were applied to oocytes during in vitro maturation (IVM) and/or SCNT procedures. Finally, antioxidant-treated SCNT embryos were compared with in vitro fertilized (IVF) embryos. $H_2O_2$ levels were analyzed in embryos at 20 h of activation, fusion or insemination by staining of embryos in $10{\mu}M$ 2'7'-dichlorodihydrofluorescein diacetate (H2DCFDA) dye, followed by fluorescence microscopy. $H_2O_2$ levels of parthenogenetic embryos were significantly lower in $25{\mu}M$ ${\beta}$-mercaptoethanol (${\beta}$-ME), $50{\mu}M$ L-ascorbic acid (Vit. C), and $50{\mu}M$ L-glutathione (GSH) treatment groups than each control group ($24.0{\pm}1.5$ vs $39.0{\pm}1.1$, $29.7{\pm}1.0$ vs $37.0{\pm}1.2$, and $32.9{\pm}0.8$ vs $36.3{\pm}0.8$ pixels/embryo, p<0.05). There were no differences among above concentration of antioxidants in direct comparison ($33.6{\pm}0.9{\sim}35.2{\pm}1.1$ pixels/embryo). Thus, an antioxidant of $50{\mu}M$ Vit. C was selected for SCNT. $H_2O_2$ levels of bovine SCNT embryos were significantly lower in embryos treated with Vit. C during only SCNT procedure ($26.4{\pm}1.1$ pixels/embryo, p<0.05) than the treatment group during IVM ($29.9{\pm}1.1$ pixels/embryo) and non-treated control ($34.3{\pm}1.0$ pixels/embryo). Moreover, $H_2O_2$ level of SCNT embryos treated with Vit. C during SCNT procedure was similar to that of IVF embryos. These results suggest that the antioxidant treatment during SCNT procedures can reduce the ROS generation level of SCNT bovine embryos.

• Nuclear Engineering and Technology
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• v.52 no.12
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• pp.2860-2866
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• 2020

Oxide dispersion-strengthened materials W-1wt%Pr₂O₃ and W-1wt%La₂O₃ were synthesized by wet chemical method and spark plasma sintering. The field emission scanning electron microscopy (FE-SEM) analysis, XRD and Vickers microhardness measurements were conducted to characterize the samples. The irradiations were carried out with a 5 keV helium ion beam to fluences up to 5.0 × 10²¹ ions/m² under 600 ℃ using the low-energy ion irradiation system. Transmission electron microscopy (TEM) study was performed to investigate the microstructural evolution in W-1wt%Pr₂O₃ and W-1wt%La₂O₃. At 1.0 × 10²⁰ He⁺/m², the average loops size of the W-1wt%Pr₂O₃ was 4.3 nm, much lower than W-1wt% La₂O₃ of 8.5 nm. However, helium bubbles were not observed throughout in both doped W materials. The effects of pre-irradiation with 1.0 × 10²¹ He⁺/m² on trapping of injected deuterium in doped W was studied by thermal desorption spectrometry (TDS) technique using quadrupole mass spectrometer. Compared with the samples without He⁺ pre-irradiation, deuterium (D) retention of doped W materials increased after He⁺ irradiation, whose retention was unsaturated at the damage level of 1.0 × 10²²D₂⁺/m². The present results implied that irradiation effect of He⁺ ions must be taken into account to evaluate the deuterium retention in fusion material applications.

• Journal of the Korean Society of Radiology
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• v.16 no.7
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• pp.953-960
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• 2022

The measurement of branching ratio of ¹⁶⁷Yb radioactive isotopes from gamma-ray spectrum of ¹⁶⁹Tm(p,3n)¹⁶⁷Yb reaction were performed by using a 100-MeV proton linear accelerator of the Korea Multi-purpose Accelerator Complex (KOMAC). The ¹⁶⁷Yb isotope has a half-life of 17.5 minutes and decays to ¹⁶⁹Tm. The gamma rays generated from the ¹⁶⁷Yb isotope were measured using an HPGe detector gamma ray spectroscopy system. The energy calibration of the detector and the efficiency measurement of the detector were determined using a standard source. The gamma rays of known main energy (62.9, 106.2, 113.3, 143.5 and 176.3 keV) were measured. On the other hand, information about the intensity of the generated gamma rays is very inaccurate. Therefore, in this study, the decay strength of the main gamma rays was accurately measured. Overall, it was different from the previously known results, and in particular, it was found that the intensity of the main decay gamma ray, such as the 113.3 and 106.2 keV gamma ray, was overestimated, and it was found that the gamma ray, such as 62.9, 116.7 and 143.5 keV was underestimated. The present results are considered to be important information in the fields of nuclear fusion, astrophysics and nuclear physics in the future.