• Polymer(Korea)
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• v.36 no.1
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• pp.71-75
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• 2012

In this study, silver nanoparticles (AgNPs) have been prepared by using aqueous $AgNO_3$ solution in the poly(vinyl alcohol) (PVA) hydrogels. PVA powders were dissolved in deionized water, and then irradiated by gamma-ray with a radiation dose of 50 kGy to make hydrogels. PVA hydrogels were dipped into 0.01 and 0.05 M $AgNO_3$ solution for 1 h respectively. After that, the swollen hydrogels were irradiated by gamma-ray at various doses to form AgNPs. UV-vis analysis indicated that the concentration of Ag NPs was enhanced by increasing absorbed dose and the concentration of $AgNO_3$. FE-SEM measurements provided further evidence for the successful formation of Ag NPs in PVA hydrogels. Also, the antibacterial effect of PVA hydrogels stabilized AgNPs against Gram-negative bacteria (S.aureus and E.coli) in liquid as well as on solid growth media has been investigated. The AgNPs consolidated in PVA hydrogel networks have an excellent antibacterial effect.

• The Korean Journal of Nuclear Medicine Technology
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• v.22 no.1
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• pp.67-75
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• 2018

Purpose The purpose of this study is to investigate and analyze the external dose rates of $^{18}F-FDG$ Whole Body PET/CT patients by distance, and to identify the main factors that contribute to the reduction of radiation dose by checking the cumulative doses of nuclear medicine technologist(NMT). Materials and Methods After completion of the $^{18}F-FDG$ Whole Body PET/CT scan($75.4{\pm}3.3min$), the external dose rates of 106 patients were measured at a distance of 0, 10, 30, 50, and 100 cm from the chest. Gender, age, BMI(Body Mass Index), fasting time, diabetes mellitus, radiopharmaceutical injection information, creatine value were collected to analyze individual factors that could affect external dose rates from a patient's perspective. From the perspective of NMT, personal pocket dosimeters were worn on the chest to record accumulated dose of NMT who performed the injection task($T_1$, $T_2$ and $T_3$) and scan task($T_4$, $T_5$ and $T_6$). In addition, patient contact time with NMT was measured and analyzed. Results External dose rates from the patient for each distance were calculated as $246.9{\pm}37.6$, $129.9{\pm}16.7$, $61.2{\pm}9.1$, $34.4{\pm}5.9$, and $13.1{\pm}2.4{\mu}Sv/hr$ respectively. On the patient's aspect, there was a significant difference in the proximity of gender, BMI, Injection dose and creatine value, but the difference decreased as the distance increased. In case of dialysis patient, external dose rates for each distance were exceptionally higher than other patients. On the NMT aspect, the doses received from patients were 0.70, 1.09, $0.55{\mu}Sv/person$ for performing the injection task($T_1$, $T_2$, and $T_3$), and were 1.25, 0.82, $1.23{\mu}Sv/person$ for performing the scan task($T_4$, $T_5$, $T_6$). Conclusion we found that maintaining proper distance with patient and reducing contact time with patient had a significant effect on accumulated doses. Considering those points, efforts such as sufficient water intake and encourage of urination, maintaining the proper distance between the NMT and the patient(at least 100 cm), and reducing the contact time should be done for reducing dose rates not only patient but also NMT.

• Radiation Oncology Journal
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• v.9 no.1
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• pp.53-58
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• 1991

From February 1987 through July 1990, the seventeen cases of inoperable intracranial arteriovenous malformation (AVM) were treated using 6 MV linear accelerator at the Division of Therapautic Radiology, Kang Nam 51. Mary's Hospital. Of seventeen cases, fourteen were male and three were female. Ages ranged from 10 to 51 years (median age of 25 years). The main symtoms were headache, epilepsy and hemiparesis in decreasing order of frequency. The middle cerebral artery is the most common origin of the feeding vessel $(41.2\%)$. Four were treated by conventionally fractionated radiation therapy (CRT, thirteen were treated by stereotactic radiosurgery (RS). duration or follow-up in CRT and RS group were 4 to 43 months (median 33 months) and 3 to 12 months (median 13 months), respectively. When the response was assessed by radiologic follow-up study, two of four CRT group showed minimal response. Of thirteen cases of RS group, two $(15.4\%)$ showed complete response, five $(38\%)$ partial response, two $(15.4\%)$ minimal response and four $(30.7\%)$ no response by the same assessment. There was no statistical significance in terms of follow-up period (p=0.22), size of lesion (p=0.82) and treated dose (p=0.05). Further accumulation of experience is recommended with proper case selection and sufficient follow-up period.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.5
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• pp.739-744
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• 2003

This study was carried out to investigate the antioxidative activity and to identify the active components of hot-water extract of Paeoniajaponica (PJ), which was a main ingredient of a herb mixture preparation recently established as a potent candidate of radioprotector in our laboratory. The water extract was fractionated with CHCl$_3$, EtOAc and n-BuOH. The extract and its fractions showed very low activity in hydroxyl radical scavenging test. In lipid peroxidation test, the extract, EtOAc and water fractions showed moderate inhibition with the ratio above 50%. In DPPH radical scavenging test, the extract, EtOAc and water fraction showed high activity with the ratio above 80%, especially. EtOAc fraction scavenged the radicals as much as synthetic antioxidant (BHA), even at low concentration. It is suggested that mai or partition for antioxidative activity of Paeonia japonica was EtOAc fraction. Subsequently, two active compounds (PJE021-1 and JE024-1) from EtOAc fraction were isolated by using MCI gel and silica gel column chromatography The two compounds inhibited remarkedly the $H_2O$$_2$-induced DNA damage in human peripheral blood lymphocytes, measured by single-cell gel electrophoresis (SCGE). PJE021-1 protected the cells to almost negative control level, dose-dependently. PJE024-1 exhibited a potent inhibition with the ratio of 71% at even low concentration (0.5 $\mu\textrm{g}$/$m\ell$). Finally, their chemical structures were identified as gallic acid (PJE021-1) and (＋)-catechin (PJE024-1), respectively, on the basis of the speculation of spectral and physical data.

• Radiation Oncology Journal
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• v.17 no.1
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• pp.16-22
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• 1999

Purpose : This study was done to analyze prognostic factors and patterns of failure of patients with histologically confirmed adenocarcinoma of the uterine cervix. Materials and Methods : From June 1988 to December 1990, a retrospective analysis was undertaken for 45 patients who were treated with curative radiation therapy for adenocarcinoma of the uterine cervix at the department of Therapeutic Radiology of Keimyung University Hospital. According to FIGO staging classification, f2 patients were stage Ib, 9 patients were lla, 19 patients were IIB, and 5 patients were lIIb. Median age of the patients was 54 years. The radiation therapy consisted of a combination of external and intracavitary irradiation. Only the pelvis was treated for external irradiation, but 6 patients were treated with extended field irradiation including paraaortic nodes. Intracavitary irradiation was performed with high dose rate sources (Co-60). Neoadiuvant chemotherapy was undertaken for 10 patients. Median and maximum follow-up duration was 64 and 116 months, respectively. Results : The overall 5-year survival rate was 55.2$\%$, and the 5-year survival rates for stage Ib, IIa, IIb, and IIIb were 100$\%$, 50.8$\%$, 46.8$\%$, and 40$\%$ (3-year survival rate), respectively. Of the many clinicopathologic variables evaluated for prognosis, only the stage and the tumor size were significant prognostic factors. Statistically, pelvic failure rates for stage Ib, IIa, IIb, and IIIb were 0$\%$, 33.3$\%$, 57.9$\%$, and 60$\%$, respectively. Distant metastasis rates were 0$\%$, 33.3$\%$, 21.1$\%$, and 40$\%$ for stage Ib, IIa, IIb, and IIIb, respectively. Especially the 6 patients who were irradiated with extended field to treat the paraaortic nodes were free of distant metastasis all. But, 9 patients (23.1$\%$) of the 39 patients who were not irradiated the paraaortic nodes were suffered and expired from uncontrolled distant metastasis. Conclusions : As compared with other studies, the survival rates were similar, but distant metastasis rates including paraaortic nodes metastasis were likely somewhat higher than expected, especially for patients with stage II. So, we think that the effect of prophylactic paraaortic nodes irradiation should be studied prospectively, especially for patients with pelvic nodes involvement or advanced stage of disease.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.6
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• pp.805-813
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• 2005

In our previous study, a novel herb mixture (HIM-I) of Angelim gigas radix, Cnidium officinale rhizoma, and Paeonia japonica radix was developed to protect the intestinal and immune systems and promote its recovery against radiation damage. In this study, a new herbal preparation (HemoHIM) with the high immune modulating activity was developed from HIM-I. HIM-I was fractionated into ethanol fraction (HIM-I-E) and polysaccharide fraction (HIM-I-P). And HemoHIM was prepared by adding HIM-I-P to HIM-I. The protective activities against $\gamma$ -irradiation were compared among HemoHIM, HIM-I and the fractions. HemoHIM and HIM-I significantly decreased the radiation-induced DNA damage in vitro, and scavenged hydroxyl radicals in a dose-dependent manner. HemoHIM showed similar activity to HIM-I. In vitro proliferation assay with mouse lymphocytes and bone marrow cells showed that HIM-I-P was remarkably higher than HIM-I and HIM-I-E in cell proliferating activity. HemoHIM showed higher activity than HIM-I and this might be associated with the higher polysaccharide content. The in vivo protective effects of HemoHIM and HIM-I were investigated in $\gamma$-irradiated mice. HemoHIM increased the surviving intestinal crypts to a similar extent compared with HIM-I. In contrast, HemoHIM appeared to be more effective than HIM-I in endogenous spleen colony formation assay. The recovery of white blood cells and lymphocytes in irradiated mice were significantly enhanced by the administration of HemoHIM. Also HemoHIM administration prolonged the survival of irradiated mice. These results showed that the novel herbal preparation, HemoHIM, effectively protected the self-renewal tissues and immune system, and promoted the survival of irradiated mice. Moreover, in comparison with HIM-I, HemoHIM maintained similar activity in the reduction of oxidative damage of self-renewal tissue but exhibited the higher activity in protection and proliferation of immune and hematopoietic cells. These results suggested that HemoHIM might be more effective than HIM-I in immune modulation as well as radioprotection.

• The Korean Journal of Nuclear Medicine
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• v.31 no.3
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• pp.330-338
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• 1997

This study investigated the method to adjust acquisition time(a) and injection dose (i) to make the best basal and subtraction images in consecutive SPECT. Image quality was assumed to be mainly affected by signal to noise ratio(S/N). Basal image was subtracted from the second image consecutively acquired at the same position. We calculated S/N ratio in basal SPECT images($S_1/N_1$) and subtraction SPECT images(Ss/Ns) to find a(time) and i(dose) to maximize S/N of both images at the same time. From phantom images, we drew the relation of image counts and a(time) and i(dose) in our system using fanbeam-high-resolution collimated triple head SPECT. Noise by imaging process depended on Poisson distribution. We took maximum tolerable duration of consecutive acquisition as 30 minutes and maximum injectible dose as 1,850MBq(50 mCi)(sum of two injections) per study. Counts of second-acquired image($S_2$), counts($S_s$) and noise($N_s$) of subtraction SPECT were as follows. $C_1$ was the coefficient of measurement with our system. $$S_2=S_1{\cdot}(\frac{30-a}{a})+background{\cdot}(1-\frac{30-a}{a})+C_1{\cdot}(30-a){\cdot}{\epsilon}{\cdot}(50-i)$$ $$Ss=S_2-\{S_1{\cdot}(\frac{30-a}{a})+background{\cdot}(1-\frac{(30-a)}{a})\}$$ $$Ns={\sqrt{N_2^2+N_1^2{\cdot}\frac{(30-a)^2}{a^2}}={\sqrt{S_2+S_1{\cdot}\frac{(30-a)^2}{a^2}}$$ In case of rest/acetazolamide study, effect(${\epsilon}$) of acetazolamide to increase global brain uptake of Tc-99m-HMPAO could be 1.5 or less. Varying ${\epsilon}$ from 1 to 1.5, a(time) and i(dose) pair to maximize both $S_1/N_l$ and Ss/Ns was determined. 15 mCi/17 min and 35mCi/13min was the best a(time) and i(dose) pair for rest/acetazolamide study(when ${\epsilon}$ were 1.2) and came to be used for our clinical routine after this study. We developed simple method to maximize S/N ratios of basal and subtraction SPECT from consecutive acquisition. This method could be applied to ECD/HMPAO and brain activation studies as well as rest/acetazolamide studies.

• Journal of radiological science and technology
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• v.27 no.3
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• pp.43-50
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• 2004

The effects of ginseng extracts on liver damage induced by high energy x-ray were studied. To one group of ICR male mice were given white(50 mg/kg/day for 7 days, orally) and fermenta ginseng extracts(500 mg/kg/day for 7 days, orally)before irrdiation. To another group were irradiated by 5 Gy dose of high energy x-ray. Contrast group were given with saline(0.1 ml). This study also investigated the effect between MDA, protein content and ginseng extracts on hepatic damage. This study measured the level of MDA(malondialdehyde), protein content in liver tissue. Administrating orally white (50 mg/kg/day for 7 days, orally)and fermenta ginseng extracts(500 mg/kg/day), the level of MDA were generally decreased and the inhibition was increased. And the protein contents were identical with control group. After irradiation, the protein contents were increased and MDA(malondialdehyde) was increased. Therefore, ginseng extracts increased antioxidative enzyme activity. And We know that the antioxidatant effect of extracts from white and fermenta ginseng protect radiation damage by direct antioxidant effect involving SOD, CAT, GPX. It was included that ginsengs can protect against the lipid peroxidation in radiation damage through its antioxidatant properties.

• Journal of radiological science and technology
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• v.27 no.2
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• pp.35-43
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• 2004

Radioprotective effects of ginseng extracts on liver damage induced by high energy x-ray were studied. To one group of ICR male mice were given white(50 mg/kg/day for 7days, orally) and fermenta ginseng extracts(500 mg/kg/day for 7days, orally) before irrdiation. To another group were irradiated by 5 Gy dose of high energy x-ray. Contrast group were given with saline(0.1 ml). This study also investigated the radioprotective effect between SOD, CAT, hydrogen peroxide and ginseng extracts on hepatic damage. This study measured the level of superoxide dismutase(SOD), catalase(CAT), hydrogen peroxide($H_2O_2$) in liver tissue. Administrating orally white (50 mg/kg/day for 7days, orally) and fermenta ginseng extracts(500 mg/kg/day), the activity of SOD, CAT were generally increased and the hydrogen peroxide($H_2O_2$) was decreased. After irradiation, the activity of SOD, CAT were generally decreased and the hydrogen peroxide($H_2O_2$) was increased. Therefore, ginseng extracts increased antioxidative enzyme activity. And We know that the antioxidatant effect of extracts from white and fermenta ginseng protect radiation damage by direct antioxidant effect involving SOD, CAT. It was included that ginseng can protect against radiation damage through its antioxidatant properties.

• Progress in Medical Physics
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• v.11 no.2
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• pp.157-165
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• 2000

Purpose: For estimation of yields of l)NA damages induced by radiation and enhanced by oxygen, a mathematical model was used and tested. Materials and Methods: Reactions of the products of water radiolysis were modeled as an ordinary time dependant equations. These reactions include formation of radicals, DNA damage, damage repair, restitution, and damage fixation by oxygen and H-radical. Several rate constants were obtained from literature while others were calculated by fitting an experimental data. Sensitivity studies were performed changing the chemical rate constant at a constant oxygen number density and varying the oxygen concentration. The effects of oxygen concentration as well as the damage fixation mechanism by oxygen were investigated. Oxygen enhancement ratio(OER) was calculated to compare the simulated data with experimental data. Results: Sensitivity studies with oxygen showed that DNA survival was a function of both oxygen concentration and the magnitude of chemical rate constants. There were no change in survival fraction as a function of dose while the oxygen concentration change from 0 to 1.0 x 10$^{7}$ . When the oxygen concentration change from 1.0 $\times$ 107 to 1.0 $\times$ 101o, there was significant decrease in cell survival. The OER values obtained from the simulation study were 2.32 at 10% cell survival level and 1.9 at 45% cell survival level. Conclusion: Sensitivity studies with oxygen demonstrated that the experimental data were reproduced with the effects being enhanced for the cases where the oxygen rate constants are largest and the oxygen concentration is increased. OER values obtained from the simulation study showed good agreement for a low level of cell survival. This indicated that the use of the semi-empirical model could predict the effect of oxygen in cell killing.