• Progress in Medical Physics
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• v.27 no.1
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• pp.14-24
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• 2016

Since the head and neck region is densely located with organs at risk (OAR), OAR-sparing is an important issue in the treatment of head and neck cancers. This study-in which different treatment plans were performed varying the head tilt angle on brain tumor patients-investigates the optimal head elevation angle for sparing normal organs (e.g. the hippocampus) and further compares the dosimetric characteristics of different types of radiation equipment. we performed 3D conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), and tomotherapy on 10 patients with brain tumors in the frontal lobe while varying the head tilt angle of patients to analyze the dosimetric characteristics of different therapy methods. In each treatment plan, 95% of the tumor volume was irradiated with a dose of 40 Gy in 10 fractions. The step and shoot technique with nine beams was used for IMRT, and the same prescription dose was delivered to the tumor volume for the 3D-CRT and tomotherapy plans. The homogeneity index, conformity index, and normal tissue complication probability (NTCP) were calculated. At a head elevation angle of $30^{\circ}$, conformity of the isodose curve to the target increased on average by 53%, 8%, and 5.4%. In 3D-CRT, the maximum dose received by the brain stem decreased at $15^{\circ}$, $30^{\circ}$, and $40^{\circ}$, compared to that observed at $0^{\circ}$. The NTCP value of the hippocampus observed in each modality was the highest at a head and neck angle of $0^{\circ}$ and the lowest at $30^{\circ}$. This study demonstrates that the elevation of the patients' head tilt angle in radiation therapy improves the target region's homogeneity of dose distribution by increasing the tumor control rate and conformity of the isodose curve to the target. Moreover, the study shows that the elevation of the head tilt angle lowers the NTCP by separating the tumor volume from the normal tissues, which helps spare OARs and reduce the delivered dose to the hippocampus.

• The Korean Journal of Nuclear Medicine
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• v.34 no.1
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• pp.82-93
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• 2000

Purpose: We characterized the signals obtained from the components of a small gamma camera using Nal(Tl)-position sensitive photomultiplier tube (PSPMT) and optimized the parameters employed in the modules of the system. Materials and Methods: The small gamma camera system consists of a Nal(Tl) crystal ($60{\times}60{\times}6mm^3$) coupled with a Hamamatsu R3941 PSPMT, a resister chain circuit, preamplifiers, nuclear instrument modules (NIMs), an analog to digital converter and a personal computer for control and display. The PSPMT was read out using a resistive charge division circuit which multiplexes the 34 cross wire anode channels into 4 signals (X+, X-, Y+, Y -). Those signals were individually amplified by four preamplifiers and then, shaped and amplified by amplifiers. The signals were discriminated and digitized via triggering signal and used to localize the position of an event by applying the Anger logic. The gamma camera control and image display was performed by a program implemented using a graphic software. Results: The characteristics of signal and the parameters employed in each module of the system were presented. The intrinsic sensitivity of the system was approximately $8{\times}10^3$ counts/sec/${\mu}Ci$. The intrinsic energy resolution of the system was 18% FWHM at 140 keV. The spatial resolution obtained using a line-slit mask and $^{99m}Tc$ point source were, respectively, 2.2 and 2.3 mm FWHM in X and Y directions. Breast phantom containing $2{\sim}7mm$ diameter spheres was successfully imaged with a parallel hole collimator. The image displayed accurate size and activity distribution over the imaging field of view Conclusion: We proposed a simple method for development of a small gamma camera and presented the characteristics of the signals from the system and the optimized parameters used in the modules of the small gamma camera.

• Journal of Animal Science and Technology
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• v.44 no.2
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• pp.239-250
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• 2002

Evaluation works of oat in mixture with rye on forage yield have not been reported. The objective of this study was to determine yield and quality of forage mixture as affected by maturity of rye cultivar and oat-rye seeding rate at Suweon from 1999 to 2000. The experiment was arranged in a split plot design with three replications. Main plots consisted of maturity of rye. such as early(cv. Koolgrazer) and late(cv. Kodiak)maturing cultivars. Sub-plots consisted of seeding rate (T1: Oat 2000 and rye 0kg/ha, Ts: Oat 150 and rye 40kg/ha, T3: Oat100 and rye 80kg/ha, T4: Oat50 and rye 120kg/ha. and T5: Oat0 and rye 160kg/ha). Crude protein(CP) content of oat-rye mixture harvested in the fall was not influenced by maturity of rye cultivar, but that of oat-rye mixture was increased from 13.6 to 19.3% as the seeding rate of rye increased(P<0.05), however, maturity of rye cultivar significantly affected CP content of oat-rye mixture in the spring(P<0.01). Acid detergent fiber(ADF) content of oat-rye mixture harvested in the spring was not significantly affected by rye cultivar, but the ADF was decreased from 27.8 to 20.7% as the seeding rate of rye increased(P$<$0.01). When rye was harveste in the spring, ADF content of late maturing cultivar 'Kodiak' was shown as 28.0%. This was lower than that of early maturing cultivar 'Koolgrazer' which was shown as 35.8%(P$<$0.01). Among treatments, neutral detergent fiber(NDF) and in vitro dry matter digestibility(IVDMD) of oat-rye mixture showed a similar trend made on ADF. In this experiment, the highest forage yield (12.356kg/ha) was obtained from early maturing rye cultivar and seeding rates of 100kg/ha of oat and 80kg/ha of rye mixture. A significant interaction between maturity of rye cultivar and seeding rate was found(P$<$0.01). The above results indicate that an early maturing rye cultivar at the seeding rate of 100kd/ha in mixtures with 80kg/ha of oat could be recommended as a succeeding cropping system after corn for silage.

• Journal of Chest Surgery
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• v.35 no.10
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• pp.705-711
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• 2002

The advantages of mitral valve reconstruction have been well established and so mitral valve reconstruction is now considered as the procedure of choice to correct mitral valve disease. This is the report of intermediate-term results of 38 cases that performed mitral valve reconstruction for valve insufficiency(the total number of mitral valve reconstruction were 49 cases, but 11 cases that performed mitral valve replacement due to incomplete reconstruction were excluded). Material and Method : From March 1991 to March 2001, 38 patients underwent mitral valve repair due to mitral valve regurgitation with or without stenosis. Mean age was 47.6$\pm$14.7 years(range 15 to 70 years) : 11 were men and 27 were women. The causes of mitral valve regurgitation were degenerative in 14, rheumatic in 21, infective in 2 and the other was congenital. Result : According to the Carpentier's pathologic classification of mitral valve regurgitation, 3 were type 1 , 16 were type II and 19 were type III. Surgical procedures were annuloplasty 15, commissurotomy 19, leaflet resection and annular plication 9, chordae shortening 11, chordae transfer 5, new chordae formation 2, papillary muscle splitting 2 and vegetectomy 2. These procedures were combined in most patients. There were 2 early death and the causes of death were respiratory failure, renal failure and sepsis. There was no late death. Valve replacement was done in 6 patients after repair due to valve insufficiency or stenosis 3 weeks, 1, 3, 51, 69, 84months later respectively. These patients have been followed up from 1 to 116 months(mean 43.0 months). The mean functional class(NYHA) was 2.36 pre-operatively and improved to 1.70. Conclusion : In most cases of mitral valve regurgitation, mitral valve reconstruction when technically feasible is effective operation that can achieve stable functional results and low surgical and late mortality.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.7
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• pp.721-728
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• 2008

DBPs(Disinfection By-Products) are most formed through the reactions between chlorine and NOM(Natural Organic Matter) in water treatment. In this study, occurrence of DBPs including THMs(Trihalomethanes) is evaluated. Also, influencing factors by the seasons and raw water quality were investigated for correlation among them and the characteristics of THMs formation by prechlorination process. This study investigated the operation condition for THMs removal depending on raw water quality. Water treatment plant from intake station to gauging well flows for about 10 hours in Y Water Supply Office. It is limited to control of THMs formation because of excessive reaction time between chlorine and THMs precursors in the intake station. Therefore, as multi-points prechlorination from intake station to gauging well, THMs formation was decreased in the water treatment, and it was willing to prevent overdosage of chlorine. The concentration of THMs was 0.021 mg/L in the summer, 0.015 mg/L in the winter, respectively. Also, THMs formation showed that 0.013 mg/L in the water of gauging well after prechlorination, 0.014 mg/L in the flocculation/sedimentation/filtration, 0.016 mg/L in the water after postchlorination, respectively. THMFP(Trihalomethane Formation Potential) removed 42.7% and 50% through the flocculation/sedimentation and filtration, respectively, and it is similar TOC removal efficiency. In this study, multi-points prechlorination from intake station to gauging well decreases in contact time and concencrations of NOM and chlorine. Also, it decreases in THMs and amount of chlorine uesd. In the result of multi-points prechlorination in the summer, the concentration of THMs was 0.013mg/L in the treated water. In view of these facts, THMs formation can be decreased approximately 50%.

• Radiation Oncology Journal
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• v.17 no.1
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• pp.84-88
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• 1999

Purpose :To develop a method for verifying a treatment setup in stereotactic radiotherapy by ma- tching portal images to DRRs. Materials and Methods : Four pairs of orthogonal portal images of one patient immobilized by a thermoplastic mask frame for fractionated stereotactic radiotherapy were compared with DRRs. Portal images are obtained in AP (anteriorfposterior) and lateral directions with a target localizer box containing fiducial markers attached to a stereotactic frame. DRRs superimposed over a planned iso-center and fiducial markers are printed out on transparent films. And then, they were overlaid over onhogonal penal images by matching anatomical structures. From three different kind of objects (isgcenter, fiducial markers, anatomical structure) on DRRs and portal images, the displacement error between anatomical structure and isocenters (overall setup error), the displacement error between anatomical structure and fiducial markers (irnrnobiliBation error), and the displacement error between fiducial markers and isocenters (localization error) were measured. Results : Localization error were 1.5$\pm$0.3 mm (AP), 0.9$\pm$0.3 mm (lateral), and immobilization errors were 1.9$\pm$0.5 mm (AP), 1.9$\pm$0.4 mm (lateral). In addition, overall setup errors were 1.0$\pm$0.9 mm (AP), 1.3$\pm$0.4 mm (lateral). From these orthogonal displacement errors, maximum 3D displacement errors($\sqrt{(\DeltaAP)^{2}+(\DeltaLat)^{2}$)) were found to be 1.7$\pm$0.4 mm for localization, 2.0$\pm$0.6 mm for immobilization, and 2.3$\pm$0.7 mm for overall treatment setup. Conclusion : By comparing orthogonal portal images with DRRs, we find out that it is possible to verify treatment setup directly in stereotactic radiotherapy.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.1
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• pp.55-64
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• 2011

This study was conducted to investigate the effects of green manure crops and cattle slurry application on rice productivity and nutrient movement in paddy land. Cropping systems used in this study were consisted of five designs, such as mono-cropping rice applied with standard fertilizer (MRS), double-cropping whole crop barley following rice applied with cattle slurry (DWBRC), double-cropping whole crop rye following rice applied with cattle slurry (DWRRC), mono-cropping rice applied with following milk vetch (MRMV) and mono-cropping rice applied with following hairy vetch (MRHV). The field experiments were conducted on the clay loam at Backsanmyun, Kimje, Chunlabukdo province in Korea for three years (May 2006 to Apr. 2009). This study was arranged in completely randomized design with three replicates. Culm and panicle length of rice were higher in MRS than other treatments. Ripened grain ratio was higher in MRS than other treatments. Yield of Grain showed high in MRS, DWBRC and DWRRC than MRMV and MRHV. The yield of dry matter (DM) of whole crop barley in DWBRC increased significantly as compared with that of rye in DWRRC. The pH, and contents of T-N, $P_2O_5$ and organic matter (OM) and exchangeable cation (Ca, Na, Mg and K) in soil samples collected at the end of the experiment were remarkably higher than those at the beginning of the experiment. The concentrations of $NO_3$-N, $NH_4$-N and $PO_4$ in discharge water in DWBRC and DWRRC were higher than MRS.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.3
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• pp.241-250
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• 1999

A field plot experiment was carried out on mixed pasture from October 1995 to October 1997 to examine the effect of weed control as affected by the difference of mixed pasture species, planning with spilt plot design which main plots of 2 treatments (companion crop Italian ryegrass Lolium multiflorum and Kentucky bluegrass Poa pratensis) are divided into subplots of 4 treatments (T1: single companion crop, T2: Tall fescue Festuca arundinasea + Orchardgrass Dactylis glomerata + Ladino clover Trifolium repens, T3 : Perennial ryegrass Lolium perenne + orchardgrass + ladino clover, T4 : orchardgrass + ladino clover). Average 2 year-dry matter yields of companion crops as whole plots, Italian ryegrass and Kentucky bluegrass, were 15,437kg/ha and 14,629kg/ha, respectively and those of T1, T2, T3 and T4 as sub plots were 14,815, 15,407, 14,629 and 15,187kg/ha respectively without statistical1y significant difference(P>0.05). Though there was no significant difference between the dry matter yields of Italian ryegrass and Kentucky bluegrass, as whole plots, at 1st harvest of second year, dry matter yields of T3 and T4, as 4,591kg/ha and 4,816kg/ha respectively, were higher than those of T1, 3,376kg/ha(P<0.05), significantly. There was a significant difference among 2nd year-average DM yields of sub plots(P<0.05), showing highest with T4 15,131kg/ha and least with T1 13,085kg/ha and T3 13,269kg/ha. Italian ryegrass, as the companion crop, was better for the control of weeds in the early spring than Kentucky bluegrass, but reached to the similar botanical composition level with Kentucky bluegrass after summer with rapid decrease of Italian ryegrass. Percentage of Kentucky bluegrass in botanical composition increased slowly, but did'nt become an important factor for the control of weeds at the end of this experiment. Using orchardgrass in mixed pasture such as T2, T3 and T4 made weeds more decreased in mixed pasture than one in single conpanion crop. There was no difference among treatments of whole or sub plots in crude protein contents of pasture taken in this study. Contents of NDF and ADF of companion crop. Italian ryegrass plots harvested in October 1997 were hither than those of Kentucky bluegrass plots(P<0.05). ADF contents of Kentucky blue grass-plots taken in July 1997 has shown to be high significantly as compared to those of Italian ryegrass plots(P<0.01). The results of this study support that the companion crop Italian ryegrass was good for weed controls only in spring of 1st year after sowing and orchardgrass in mixed pastures played good roles for increase of dry matter yield and weed control.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.3
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• pp.233-240
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• 1999

Understanding of the relationships between seeding rate and planting date is important for production of spring oats during the fall season. Therefore, this experiment was conducted to investigate seeding rate and planting date effects on forage performance and quality of spring oats(Avena sativa L.) at Suweon in 1997. The experiment was arranged in a split plot design with three replications. The main plots consisted of different seeding rates such as 150, 200, and 250kg/ha. The subplots consisted of different planting dates of spring oats such as 15, 22, and 29 August and 5 September. Dry matter content of oats was significantly decreased(P<0.01) as the planting date was delayed except the planting date of 5 September(24.8%). Dry matter content of forage oats planted on 15, 22, and 29 August was 23.0, 21.5, and 20.5%, respectively. A seeding $rate\;{\times}\;planting$ date interaction for dry matter content was highly significant(P<0.01). Crude protein content of oats was significantly increased(P<0.01) from 15.6 to 27.9% as the planting was delayed, while a significant seeding $rate\;{\times}\;planting$ date interaction for crude protein content of oats was observed. Acid detergent fiber(ADF) and neutral detergent fiber(NDF) contents of oats increased with early planting(P<0.01), but there was no significant difference among the seeding rates. ln vitro dry matter digestibility(IVDMD) of oats was significantly increased(P<0.01) as the seeding rate was increased together with late planting. Average dry matter yield of oats decreased(P<0.01) from 2,647 to 615kg/ha as the planting was delayed, but there was no significant difference among the seeding rates. A seeding $rate\;{\times}\;planting$ date interaction was observed for average dry matter yield of oats that the seeding rate increase in this experiment showed better at early planting dates. Crude protein yield of oats increased from 171 to 410kg/ha as the planting was delayed, and a significant increases(P<0.01) for crude protein yield was found among the seeding rates. ln vitro digestible dry matter(IVDDM) yield of oats decreased(P<0.01) as the planting was delayed, but there was no significant difference among the seeding rates. A significant seeding $rate\;{\times}\;planting$ date interaction for lVDDM of oats was found. The results of this study indicate that both the seeding rate of 200kg/ha and early planting before 29 August would be recommendable for forage yield and quality of oats in Korea.

• Radiation Oncology Journal
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• v.12 no.3
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• pp.393-399
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• 1994

Spinal cord compression, an oncologic emergency, is a rare complication of hematologic malignancy Our experience was obtained with a series 32 Patients following retrospective analysis for assessing the role of radiation therapy and identifying the prognostic factors affecting on treatment outcome. Diagnosis was usually made by means of radiologic study such as myelography or computerized tomography (CT) or magnetic resonance imaging (MRI) and neurologic examination. Five cases were diagnosed by subjective symptom only with high index of suspicion. In 31 cases, the treatment consisted in radiation therapy alone and the remained one patient had laminectomy before radiation therapy because of diagnostic doubts. Total treatment doses ranged from 800 cGy to 4000 cGy with median of 2000 cGy. Initially large fraction size more than 250 cGy were used in 13 patients with rapidly progressed neurologic deficit. The clinical parameters considered in evaluating the response to treatment were backache, motor-sensory performance and sphincter function. Half of all patients showed good response. Partial response and no response were noted in $37.5\%$ and $12.5\%$, respectively. Our results showed higher response rate than those of other solid tumor series. The degree of neurologic deficit at that time of diagnosis was the most important predictor of treatment outcome. The elapsed time from development of symptoms to start of treatment was significantly affected on the outcome. But histology of primary tumor total dose and use of initial large fraction size were not significantly affect on the outcome. These results confirmed the value of early diagnosis and treatment especially in radiosensitive hematologic malignancy.