• Radiation Oncology Journal
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• v.11 no.2
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• pp.439-448
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• 1993

The B-type gamma knife unit was installed at Kyung-Hee University Hospital in March 1992. The selective beam plugging method can be used to reduce the low percentage isodose profiles of normal sensitive organ and to modify the isodose curves of treatment volume for better shaping of the target volume. For representing the changes of the low percentage isodose profiles, the variations of dose distribution for several cases were discussed in this paper. The film dosimetry was peformed for the evaluation of calculated isodose profiles predicted by KULA dose planning system. The results were verified by RFA-3 automatic densitometry. The clinical application of selective beam shielding method was peformed in 17 patients in 100 patients who have undergone gamma knife radiosurgery for a year. The calculated and the measured isodose profiles for the high percentage regions were well consistent with each other. When the target of pituitary tumor is macro-size, the selective beam shielding method is the most applicable method. When the target size, however, is small, the correct selection of the proper helmet size is very important. All patients were exposed almost about 3~12 Gy for brain stem, and 3~11.2 Gy for optic apparatus. It is recommended that the same or other plugging patterns with multiple isocenters should be used for protection of the radiosensitive normal structures with precise treatment of CNS lesions.

• Journal of Pharmaceutical Investigation
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• v.40 no.2
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• pp.101-107
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• 2010

A rapid and sensitive reversed-phase high performance liquid chromatography (HPLC) method was developed for the determination of N-(-4-Chlorophenyl)-6-hydroxy-7-methoxy-2-chromanecarboxamide (KAL-1120), a novel anti-inflammation agent, in the rat plasma. The method was applied to analyze the compound in the biological fluids such as bile, urine and tissue homogenates. After liquid-liquid extraction, the compound was analyzed on an HPLC system with ultraviolet detection at 275 nm. HPLC was carried out using reversed-phase isocratic elution with a $C_{18}$ column, a mobile phase of a mixture of acetonitril (40 v/v%) at a flow rate of 1.0 mL/min. The chromatograms showed good resolution and sensitivity and no interference of plasma. The calibration curve for the drug in plasma was linear over the concentration range of 0.05-50 ${\mu}g$/mL. The intra- and inter-day assay accuracies of this method ranged from 0.06% to 9.33% of normal values and the precision did not exceed 6.28% of relative standard deviation. The plasma concentration of KAL-1120 decreased to below the quantifiable limit at 1.5 hr after the i.v. bolus administration of 2-10 mg/kg to rats ($t_{1/2,({\alpha})}$ and $t_{1/2,({\beta})$ of 2.15 and 26.7 min at a dose of 2 mg/kg, 3.91 and 33.0 min at a dose of 10 mg/kg, respectively). The steady-state volume of distribution ($V_{dss}$) and the total body clearance ($CL_t$) were not significantly altered in rats given doses from 2 to 10 mg/kg. Of the various tissues tested, KAL-1120 was mainly distributed in the lung and heart after i.v. bolus administration. KAL-1120 was detected in the bile by 30 min after its i.v. bolus administration. However, the concentration in the urine after i.v. bolus administration became too low to measure, suggesting that KAL-1120 is mostly excreted in the bile. In conclusion, this analytical method was suitable for the preclinical pharmacokinetic studies of KAL-1120 in rats.

• Journal of Food Hygiene and Safety
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• v.5 no.1
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• pp.7-12
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• 1990

The disposition of Brazilin including plasma concentration-time profiles, excretions via urine and bile, and plasma protein binding was investigated after intravenous or oral administration of radio labeled Brazilin ($^3H-Brazilin$) to male Wistar rats. The main pharmac:okinetic parameters were as follows; $t\;_{ 1/2}$, 13.71 hr; AUC, $53.38\;\mu\textrm{g}{\cdot}hr/ml$; AUMC, $1013.4I\;\mu\textrm{g}{\cdot}hr^2/ml$, MRT, 18.95 hr; Vss, 17778 mllkg and CL, 936.77 ml/hr.kg. The 2nd peak was found in the plasma concentration-time profiles indicating potential enterohepatic circulation. The enterohepatic circulation was supported by the bile excretion. After oral administration, about 64.4 % of administered radioactivity was excreted into the bile within 10 hours and its excretion rate reached maximum at 3 hours after administration. The Vss was extremely high, 17.8 l/kg indicating distribution of brazilin in most organs (tissues) with high concentration of brazilin in some organs. Brazilin was distributed into most of organs (spleen, adrenal, pancreas, kidney, thymus, lung, heart, liver, prostate, epididymus, testis, fat, muscle and done) except brain. High concentration of Brazilin was detected especially in liver, kidney, epididymus and testis. Approximately, 62.9% and 44.1% of the dose was excreted for intravenous and oral administration, respectively. About 80% of the dose eventually excreted into urine was excreted within 24 hr after dosing. Plasma protein binding of brazilin resulted in $40\;{\pm}\;4%$ by ultrafiltration method.

• Journal of Food Hygiene and Safety
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• v.22 no.1
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• pp.23-28
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• 2007

The residue depletion of streptomycin was investigated in the olive flounder (Paralichthys olivaceus), rockfish (Sebastes schlegeli), and red sea bream (Pagrus major) after consecutive three days treatment with dipping water at a dose of 20 g/ton water. Fishes were sampled for muscle on 1st, 2nd, 3rd, 4th, and 5th day after treatment. Streptomycin concentrations were determined by high performance liquid chromatography with tandem mass spectrometry. The recovery rates of streptomycin in muscle samples ranged from 87.2 to 102.3% and from 80.4 to 94.1% for the concentration of 0.05 mg/kg and 0.1 mg/kg, respectively. Streptomycin concentrations detected on the 1st day after treatment were 0.066, 0.058, and 0.073 mg/kg in muscles of olive flounder, rockfish, and red sea bream, respectively. At day 2, residue concentrations of all samples were believed to decrease to lower than 0.05 mg/kg, the detection limit. From results of the present study, a withdrawal period of streptomycin is proposed on 3 days after consecutive three days treatment with dipping administration at a dose of 20 g/ton water to avoid the presence of excessive residues of the edible muscles of olive flounder, rockfish, and red sea bream. The present study showed that residue concentrations of streptomycin decreased to below 0.05 mg/kg after treatment 2nd day.

• Journal of Food Hygiene and Safety
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• v.25 no.2
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• pp.143-147
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• 2010

Chronic exposure to Arsenic (As) causes significant human health effects including various cancers. Total As concentrations from 300 polished rice samples cultivated near the mining areas in Korea were analyzed to estimate a probabilistic assessment of human health risk from As-contaminated rice. The mean of total As concentrations in rice was 0.09 mg/kg and lognormal distribution model was set for total As concentrations. Human health risk for As in rice was estimated using gender-specific rice consumption data and average daily dose (ADD). While cancer risk (CR) and hazard quotient (HQ) were calculated using oral cancer slope factor (OCSF) and Reference dose (RfD) suggested by the U.S. EPA. Mean of CR posed by total As was 2.16 (for male) and 1.83 (for female) per 10,000. The HQ for general population from rice cultivated near the mining areas in Korea was below 1 as the $50^{th}$ percentile of general population. However, less than 10% of general population consuming rice cultivated near the mining areas would exceed 1.0. This result is similar with those from each gender-specific group.

• Journal of Life Science
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• v.21 no.11
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• pp.1573-1578
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• 2011

Milk thistle (silybum marianum) is a famous dietary supplement widely used in the United States and Europe. Silbinin is a major biologically active compound of milk thistle and has strong antioxidant and radical scavenger activities. Anticancer activities, as well as chemopreventive effects on various cancer cell lines, including prostate, lung, colon, skin, and bladder, have also been reported in silbinin. In the present study, we investigated the anticancer effects of silibinin and apoptosis through cell cycle arrest on prostate cancer cell PC-3. We performed cell viability by MTT assay and western blotting to confirm cell cycle check point proteins such as cyclin A/D1/E and cyclin-dependent kinase (CDK) 2/4/6. To quantify silibinin-induced apoptotic cell death of PC-3, Annexin V and PI double staining was performed by flow cytometry, by which its cell distribution was determined. As a result, silibinin inhibited the cell growth of PC-3 cells in a time- and dose-dependent manner, and its treatment resulted in cell cycle arrest at the G1 phase. Also the level of cell cycle check point proteins (cyclin, CDK) was decreased by silibinin in a dose-dependent manner. Taken together, we suggest that apoptosis of prostate cancer cell line PC-3 induced by silibinin is associated with cell cycle arrest through decrease of cell cycle check point proteins, caspase-3 activation and poly (ADP-ribose) polymerase (PARP) cleavage.

• Progress in Medical Physics
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• v.12 no.2
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• pp.125-131
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• 2001

We was investigate the dosimetric characteristics of the virtual wedge and it compared to the conventional fixed wedge. Also we was evaluate the quality factor of the experimental multi-channel dosimetry system for virtual wedge. Recently virtual wedge technique and wedge fraction methods are available through the computer controlled asymmetric collimator or the independent jaw in medical linear accelerator for radiation therapy. The dosimetric characteristics are interpreted by radiation field analyzer RFA-7 system and PTW-UNIDOS system. Experimental multi-channel dosimetry system for virtual wedge was consists of the electrometer, the solid detector and array phantom. The solid detectors were constructed using commercially diodes for the assessment of quality assurance in radiotherapy. And it was used for the point dose measuring and field size scanning. The semiconductor detector and ion chamber were positioned at a dmax, 5 cm, 10 cm, 20 cm depth and its specific ratio was determined using a scanning data. Wedge angles in fixed and virtual type are compared with measurements in water phantom and it is shown that the wedge angle 15$^{\circ}$, 30$^{\circ}$, 45$^{\circ}$were agree within 1$^{\circ}$ degree in 6, 10 MV photon beams. In PDD and beam flatness, experimental multi-channel disimetry system was capable of reproduceing the measured values usually to within $\pm$2.1% the statistical uncertainties of the data. It was used to describe dosimetric characteristics of virtual wedge in clinical photon beams. Also we was evaluate optimal use of the virtual wedge and improve the quality factor of the experimental multi-channel dosimetry system for virtual wedge.

• Progress in Medical Physics
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• v.25 no.4
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• pp.242-247
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• 2014

To see the discrepancies between the calculated and the delivered dose distribution of IMRT fields for respiratory-induced moving target according to the motion ranges. Four IMRT plans in which there are five fields, for lung and liver patients were selected. The gantry angles were set to $0^{\circ}$ for every field and recalculated using TPS (Eclipse Ver 8.1, Varian Medical Systems, Inc., USA). The ion-chamber array detector (MatriXX, IBA Dosimetry, Germany) was placed on the respiratory simulating platform and made it to move with ranges of 1, 2, and 3 cm, respectively. The IMRT fields were delivered to the detector with 30~70% gating windows. The comparison was performed by gamma index with tolerance of 3 mm and 3%. The average pass rate was 98.63% when there's no motion. When 1.0, 2.0, 3.0 cm motion ranges were simulated, the average pass rate were 98.59%, 97.82%, and 95.84%, respectively. Therefore, ITV margin should be increased or gating windows should be decreased for targets with large motion ranges.

• Radiation Oncology Journal
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• v.34 no.1
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• pp.26-33
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• 2016

Purpose: To compare the dose distribution between carotid sparing intensity modulated radiotherapy (IMRT) and opposed lateral field technique (LAFT), and to determine the effects of carotid sparing IMRT in early glottic cancer patients who have risk factors for atherosclerosis. Materials and Methods: Ten early glottic cancer patients were treated with carotid sparing IMRT. For each patient, the conventional LAFT plan was developed for comparison. IMRT and LAFT plans were compared in terms of planning target volume (PTV) coverage, conformity index, homogeneity index, and the doses to planning organ at risk volume (PRV) for carotid arteries, spinal cord and pharyngeal constrictor muscle. Results: Recurrence was not observed in any patients during the follow-up period. $V_{95%}$ for PTV showed no significant difference between IMRT and LAFT plans, while $V_{100%}$ was significantly higher in the IMRT plan (95.5% vs. 94.6%, p = 0.005). The homogeneity index (11.6%) and conformity index (1.4) in the IMRT plan were significantly better than those in the LAFT plans (8.5% and 5.1, respectively) (p = 0.005). The median $V_{5Gy}$ (90.0%), $V_{25Gy}$ (13.5%), and $V_{50Gy}$ (0%) for carotid artery PRV in the IMRT plan were significantly lower than those in the LAFT plan (99.1%, 89.0%, and 77.3%, respectively) (p = 0.005). Conclusion: Our study suggests that carotid sparing IMRT can significantly decrease the dose to carotid arteries compared to LAFT, and it would be considered for early glottic cancer patient with high risk of atherosclerosis.

• Radiation Oncology Journal
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• v.16 no.4
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• pp.455-467
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• 1998

Purpose : To evaluate influences associated with radiation treatment planning obtained with the patient breathing freely. Materials and Methods : We compared reduction or elimination of planning target volume (PTV) margins with 2-D conventional plan with inclusion of PTV margins associated with breathing with 3-D conformal therapy. The respiratory non gated 3-D conformal treatment plans were compared with respiratory gated conventional 2-D plans in 4 patients with hepatocellular carcinomas. Isodose distribution, dose statistics, and dose volume histogram (DVH) of PTVs were used to evaluate differences between respiratory gated conventional 2-D plans and respiratory non gated 3-D conformal treatment plans. In addition. the risk of radiation exposure of surrounding normal liver and organs are evaluated by means of DVH and normal tissue complication probabilities (NTCPs). Results : The vertical movement of liver ranged 2-3 cm in all patients. We found no difference between respiratory gated 2-D plans and 3-D conformal treatment plans with the patients breathing freely. Treatment planning using DVH analysis of PTV and the normal liver was used for all patients. DVH and calculated NTCP showed no difference in respiratory gated 2-D plans and respiratory non gated 3-D conformal treatment plans. Conclusion : Respiratory gated radiation therapy was very important in hepatic tumors because radiation induced hepatitis was dependent on remaining normal liver volume. Further investigational studies for respiratory gated radiation.