No abstract available.

No abstract available.

High Dose Rate Remote Afterloading system was installed at Wonkwang Universi-ty Hospital in January 1994. In this report, the calibration of a Gammamed 12-i High Dose Rate Remote Afterloading system and the radiation survey around the facility after design and construct a shieding room are discussed. The radiation survey of the facility indicates that the use of ordinary concrete shielding of existing room will provide adequate shielding. Also, the methodologies for performing source calibra-tion are presented.
Calibration* ; Carboxymethylcellulose Sodium

PURPOSE: To report three various cases of retinal hemorrhages caused by Plasmodium vivax malaria. CASE SUMMARY: Two 55-year-old male patients and a 52-year-old male patient with cyclic high fever were admitted to the department of internal medicine. Three of the patients were diagnosed with malaria caused by P. vivax based on a peripheral blood smear. The patients were treated with hydroxychloroquine and premaquine but complained of decreased visual acuity. The patients were examined with funduscopy, fluorescein angiography, and optical coherence tomography. The first case showed 2 areas of retinal hemorrhages on the macular in the right eye and 1 area of retinal hemorrhage in the left eye. The second case showed many cotton-wool spots along with a number of small retinal hemorrhages and tortuous blood vessels in both eyes. The third case showed 1 area of retinal hemorrhage in the right eye and many cotton-wool spots in both eyes. CONCLUSIONS: P. vivax malaria rarely causes retinal hemorrhage. Manifestations of retinal hemorrhage and degree of visual acuity loss may vary among patients. P. vivax malaria should be considered when patients with unexplained high fever present with retinal hemorrhage, even without a history of overseas travel.
Blood Vessels ; Eye ; Fever ; Fluorescein Angiography ; Humans ; Hydroxychloroquine ; Internal Medicine ; Malaria ; Malaria, Vivax ; Male ; Middle Aged ; Plasmodium ; Plasmodium vivax ; Retinal Hemorrhage ; Retinaldehyde ; Tomography, Optical Coherence ; Visual Acuity

No abstract available.
Humans ; Insulin Resistance* ; Insulin*

Purpose: We performed three-dimensional (3D) dose reconstruction-based pretreatment verification to evaluate gamma analysis acceptance criteria in volumetric modulated arc therapy (VMAT) for prostate cancer. Materials and Methods: Pretreatment verification for 28 VMAT plans for prostate cancer was performed using the COMPASS system with a dolphin detector. The 3D reconstructed dose distribution of the treatment planning system calculation (TC) was compared with that of COMPASS independent calculation (CC) and COMPASS reconstruction from the dolphin detector measurement (CR). Gamma results (gamma failure rate and average gamma value [GFR and γAvg]) and dose-volume histogram (DVH) deviations, 98%, 2% and mean dose-volume difference (DD98%, DD2% and DDmean), were evaluated. Gamma analyses were performed with two acceptance criteria, 2%/2 mm and 3%/3 mm. Results: The GFR in 2%/2 mm criteria were less than 8%, and those in 3%/3 mm criteria were less than 1% for all structures in comparisons between TC, CC, and CR. In the comparison between TC and CR, GFR and γAvg in 2%/2 mm criteria were significantly higher than those in 3%/3 mm criteria. The DVH deviations were within 2%, except for DDmean (%) for rectum and bladder. Conclusions The 3%/3 mm criteria were not strict enough to identify any discrepancies between planned and measured doses, and DVH deviations were less than 2% in most parameters. Therefore, gamma criteria of 2%/2 mm and DVH related parameters could be a useful tool for pretreatment verification for VMAT in prostate cancer.

PURPOSE: The dose calculation program for the Buchler type remote afterloading system was developed. This program also can be used to calculate dose for various sealed sources. METHODS AND MATERIALS: We determined the source length and distribution by dividing the program disk to 72 points. The dose rate for the each program disk and source was calculated. The dose rate table for the xy coordinate was established. The dose rate for the interesting points of the patient were calculated by using this table. We also made isodose curve from this calculations. RESULTS: The storage size for the dose rate table were increased.But the calculation of the dose rate for the patient were carried out rapidly. So we could get real time calculation. CONCLUSION: By using this program, we could calculate the dose rate for the various oints of the patient quickly and accurately. This program will be useful for the treatment with various linear sources.
Brachytherapy ; Humans

We investigated the electrophysiological changes in the cerebral cortical evoked potentials(CEP's) and subsequent changes in the regional cerebral blood flow(rCBF) following increased intracranial pressure(ICP) in cats. A small balloon connected to a fine polyethylene tube was placed on the epidural space of the left parietal region through a small burr hole and inflated with saline in increment of 0.2 ml to simulate the expanding mass. The ICP was maintained at 150 mmH2O and 250 mmH2O levels during the experimental period. The study was conducted with 30 adult cats, weighing between 2.7 and 4.5kg. The animals were anesthetized with pentobarbital (50mg/kg) intraperitonially and tracheostomy was performed to maintain self respiration. Two small burr holes were made on both frontal regions for rCBF measurement and a small burr hole was made on the right primary sensorimotor cortex for a cerebral cortical stimulating electrode. A recording electrode for CEP's was placed on the dura of the left cerebellar hemisphere. For experiments, animals were divided into 3 groups. Group I:Animals(n=10) with 80mmH2O of ICP, Group II:Animals(n=10) with 150 mmH2O of ICP, Group III:Animals(n=10) with 250mmH2O of ICP. The CEP's and rCBF measurements were carried out in each animal before and immediately after increased ICP(IICP), at the 30th min, 60th min, 90th min, 120th min, 150th min and 180th min after IICP. The rCBF was measured by hydrogen clearance method. The results were as follows ; 1. A significant elevation of the systolic blood pressure was observed after the 60th min in both IICP groups. 2. 1) Group II animals showed a significant reduction of rCBF by 10.5% and 39.5% in the right frontal lobe at the 60th min and 180th min after IICP, and by 19.8% and 57.7% in the left frontal lobe at the 60th min and 180th min after IICP, respectively. 2) Group III animals showed also a significant reduction of rCBF by 18.2% and 54.4% in the right frontal lobe at the 60th min and 180th min after IICP, and by 62.9% and 84.7% in the left frontal lobe at the 60th min and 180th min after IICP, respectively. 3) Reductions of the rCBF of the left frontal lobe in the Group III animals were greater than those of the Group II animals. 3. 1) Changes of amplitude and latency in the CEP's were more prominent in the Group III animals than those of the Group II animals. 2) Changes of the late components of CEP's(N2) might represent derangements of the neural activity of the descending reticular formation in brainstem. 4. A close correlation was found between CEP's and rCBF changes, which suggested being a threshold relationship. In conclusion, it is assumed that the detection of CEP's in the cerebellum is a quite valuable prognostic tool to evaluate the neural activity of the non-specific reticular formation and specific somatosensory pathways in the acute intracranial hypertension. The prolongated latencies and suppressed amplitude in the CEP's indicate the presence of damages in brainstem multisynaptic pathways.
Adult ; Animals ; Blood Pressure ; Brain Stem ; Cats ; Cerebellum ; Electrodes ; Epidural Space ; Frontal Lobe ; Humans ; Hydrogen ; Intracranial Hypertension ; Intracranial Pressure* ; Pentobarbital ; Polyethylene ; Rabeprazole ; Respiration ; Reticular Formation ; Tracheostomy

In the previous studies, we found that lumbrokinase an, extract from Korean earthworm, had a strong in vitro thrombolytic effect, and that when added to thrombin had a significant effect in reducing fatality rate in thrombin-induced lung infarction mice model. To determine whether it also has in vivo thrombolytic effect in cerebral embolism model using 9 Spraw Dawly male rats of 200 to 300gm, we cannulated the extemal carotid artery lene tubes and occluded the pterygopalatine arteries. Via the extemal carotid artery, we injected 1 mm3 of human blood clots which were previously mixed with Tc-99m sulfur colloid. After confirming the intracranially situated clot by camera, we injected 3cc of following fiuids to each group of three rats: saline, urokinase, lumbrokinase fraction m Then using Gamma camera of 64*64 m obtained for 1 minute in every 30 minutes. After 150 minutes radioactivities of the clots in the brain were 3.02%, 21 02% urokinase, and lumbrokinase treated animals respectively. In the liver, the uptake of radioactivities was accordingly increased. Brain sections showed no Significant intracranial bleeding in any of the treated animals. Therefore, we conclude that lumbrokinase has in vivo thromboembolism model without producing significant intracranial bleeding. However, compared with its in vitro effects the in vivo effects appear to be less potent. Futher experiments with better designed animal models are warranted.
Animals ; Arteries ; Brain ; Carotid Arteries ; Gamma Cameras ; Hemorrhage ; Humans ; Infarction ; Intracranial Embolism ; Liver ; Lung ; Male ; Mice ; Models, Animal ; Oligochaeta ; Radioactivity ; Rats* ; Technetium Tc 99m Sulfur Colloid ; Thrombin ; Thromboembolism* ; Urokinase-Type Plasminogen Activator

PURPOSE: We compared the calculated percent depth dose curves of 6 MeV electron beam to that of measured to evaluate the usefulness of Monte-Carlo simulation method in radiation physics. MATERIALS AND METHODS: The radiation dose values of 6 MeV electron beam using EGS4 code with one million histories in water were compared values that were measured form the depth dose curve of electron beam irradiated by medical accelerator ML6M. The central exis dose values were calculated according the changing field size, such as 5 X 5, 10 X 10, 15 X 15, 20 X 20 cm2. RESULTS: The value calculated showed a very similar shape to depth dose curve. The calculated and measured value of Dmax at 10 X 10cm2 cone is 15mm and 14mm respectively. The calculated value of the surface radiation dose rate is 65.52% and measured one is 76.94%. The surface radiation dose rate has vaied from 64.43% to 66.99. The calculated values of Dmax are in the range between 15mm and 18mm. The calculated value was fitted well with measured value around the Dmax area, excluding build up range and below the 90% depth dose area. CONCLUSION: This result suggested that the calculation of dose value can be replace the direct measurement of the dose for radiation therapy. Also, EGS4 may be a very convenient program to assess the effect of radiation dose using by personal computers.
Microcomputers ; Water