• Progress in Medical Physics
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• v.22 no.1
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• pp.3-11
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• 2011

The purpose of this study was to evaluate feasibility of Vertical Multileaf Collimator for determination of irradiation size using Vertical Multileaf Collimator and lead block to determine 4 different irradiation shape in case of Co-60 gamma-ray and 6 MV X-ray. We chose ion chamber, glass dosimeter and EBT chromic film to compare with Vertical Multileaf Collimator results and lead block results. In case of Co-60 gamma-ray and 6 MV X-ray, the central axis point dose normalized at reference field of lead block with ion chamber results for Vertical Multileaf Collimator were estimated higher than lead block about 5.1%, 4.2%. In case of Co-60 gamma-ray, the central axis point dose normalized at reference field of lead block with glass dosimeter results for Vertical Multileaf Collimator were estimated higher than lead block about 2.2%, 7.8%, 7.2%, 4.0% for reference, circle, triangle, cross field, respectively. In case of 6 MV X-ray, the central axis point dose normalized at reference field of lead block with glass dosimeter results for Vertical Multileaf Collimator were estimated higher than lead block about 6.7%, 6.2%, 3.8%, 6.2% for reference, circle, triangle, cross field, respectively. The results of EBT chromic film, Vertical Multileaf Collimator of penumbra size for all irradiation shape was smaller than lead block of those size that 2.0~3.5 mm for Co-60 gamma-ray, 0.5~1.0 mm for 6 MV X-ray. The results from this study, radiation treatment volume that results in shielding block can be minimized. In addition, during radiation treatment for 2, 3-dimensional radiation therapy using a Vertical Multileaf Collimator of this survey can be used to determine variety of irradiation fields.

• Radiation Oncology Journal
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• v.28 no.4
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• pp.219-223
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• 2010

Purpose: To test the radiosensitizing effect of the newly synthesized novel histone deacetylase inhibitor, SK-7041 in vivo. Materials and Method: The RIF-l cell line was implanted into the back of a 6-week-old female C3H mouse, intradermally, The mice were grouped into control, drug, radiation (RT), and RT+drug group. SK-7041, 4 mg/kg was administered intraperitoneally for six cycles every 12 hours for mice in the drug and RT+drug group, An identical volume of phosphate buffered saline (PBS) was administered at the same frequency to mice in the control and RT groups. A single 5 Gy fraction was delivered to mice in RT and RT+drug group 6 hours after the fourth delivery. The volume of the implanted tumor was measured every 2~3 days to formulate the growth delay curve. Results: For the control, drug, RT, and RT +drug groups, the average duration for implanted tumor to reach a volume of $1,500mm^3$ was 10 days, 10 days, 9 days, and 12 days, respectively. Moreover, the tumor volume on D14 was $276.7mm^3$, $279.9mm^3$, $292.5mm^3$, and $185.5mm^3$, respectively (p=0.0004). The difference for the change in slope for the control and drug versus the RT and RT+drug groups were borderline significant (p=0.0650). Conclusion: The results of this study indicate that SK-7041 has a radiosensitizing effect for the RIF-1 cell line in vivo at a low concentration and this effect may be synergistic. Implementing this result to clinical trial is warranted.

• Radiation Oncology Journal
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• v.18 no.4
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• pp.251-256
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• 2000

Purpose : To evaluate efficacy and complication of stereotactic radiosurgery using stereotactic body frame. Methods and Materials :From December 1997 to June 1999, 11 patients with primary and metastatic tumors were treated with stereotactic radiosurgery using stereotactic body frame(Precision TherapyTu). Three patients were treated with primary hepatoma and seven with metastatic tumor from liver, lung, breast, trachea and one with arteriovenous malformation on neck. We used vacuum pillow for immobilization and made skin marker on sternum and tibia area with chest marker and leg marker. Diaphragm control was used for reducing movement by respiration. CT-simulation and treatment planning were peformed. Set-up error was checked by CT-Simulator before each treatment. Dose were calculated on the 80$\~$90$\%$ isodose of isocenter dose and given consecutive 3 fractions for total dose of 30 Gy (10 Gy/fraction). Results :Median follow-up was 12 months. One patient (9$\%$) showed complete response and four Patients (36$\%$) showed partial response and others showed stable disease. Planning target volumes (PTV) ranged from 3 to 111 cc (mean 18.4 n). Set-up error was within 5 mm in all directions (X, Y, Z axis). There was no complication in all patients. Conclusion :In Primary and metastatic tumors, stereotactic body frame is very safe, accurate and effective treatment modality.

• Radiation Oncology Journal
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• v.23 no.2
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• pp.92-97
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• 2005

Purpose : Reports on the outcome of curative radiotherapy for the primary hepatocellular carcinoma (HCC) are rarely encountered in the literature. in this study, we report our experience of a clinical trial where fractionated stereotactic radiotherapy (SRT) was used in treating a primary HCC. Materials and Methods : A retrospective analysis was peformed on 20 patients who had been histologically diagnosed as HCC and treated by fractionated SRT. The long diameter of tumor measured by CT was $2\~6.5$ cm (average: 3.8 cm). A single dose of radiation used in fractionated SRT was S or 10 Gy: each dose was prescribed based on the planning target volume and normalized to $85\~99\%$ isocenter dose. Patients were treated $3\~5$ times per week for 2 weeks, with each receiving a total dose of 50 Gy (the median dose: 50 Gy). The follow up period was $\~55$ months (the median follow up period: 23 months). Results : The response rate was $50\%$ (12 patients), with 4 patients showing complete response ($20%$), 8 patients showing partial response ($40\%$), and 8 patients showing stable disease ($40\%$). The 1-year and 2-year survival rates were $70.0\%$ and $43.1\%$, respectively, and the median survival time was 20 months. The 1-year and 2-year disease free survival rates were $65\%$ and $32.5\%$, respectively, and the median disease-free survival rate was 19 months. Some acute complications of the treatment were noted as follows: dyspepsia in 12 patients ($60\%$), nausea/emesis in 8 patients ($40\%$), and transient liver function impairment in 6 patients ($30\%$). However, there was no treatment related death. Conclusion : The study indicates that fractionated SRT is a relatively safe and effective method for treating primary HCC. Thus, fractionated SRT may be suggested as a local treatment for HCC of small lesion and containing a single lesion, when the patients are inoperable or operation is refused by the patients. We thought that fractionated SRT is a challenging treatment modality for the HCC.

• The Journal of Korean Society for Radiation Therapy
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• v.28 no.2
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• pp.179-186
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• 2016

Purpose : To figure out if the treatment plan for rectum, bladder and prostate that have a lot of interfraction errors satisfies dosimetric limits without adaptive plan by analyzing MR image. Materials and Methods : This study was based on 5 prostate cancer patients who had IMRT(total dose: 70Gy) Using ViewRay MRIdian System(ViewRay, ViewRay Inc., Cleveland, OH, USA) The treatment plans were made on the same CT images to compare with the plan quality according to adaptive plan, and the Eclipse(Ver 10.0.42, Varian, USA) was used. After registrate the 5 treatment MR images to the CT images for treatment plan to analyze the interfraction changes of organ, we measured the dose volume histogram and the changes of the absolute volume for each organ by appling the first treatment plan to each image. Over 5 fractions, the total dose for PTV was $V_{36.25}$ Gy $${\geq_-}$$ 95%. To confirm that the prescription dose satisfies the SBRT dose limit for prostate, we measured $V_{100%}$, $V_{95%}$, $V_{90%}$ for CTV and $V_{100%}$, $V_{90%}$, $V_{80%}$ $V_{50%}$ of rectum and bladder. Results : All dose average value of CTV, rectum and bladder satisfied dose limit, but there was a case that exceeded dose limit more than one after analyzing the each image of treatment. After measuring the changes of absolute volume comparing the MR image of the first treatment plan with the one of the interfraction treatment, the difference values were maximum 1.72 times at rectum and maximum 2.0 times at bladder. In case of rectum, the expected values were planned under the dose limit, on average, $V_{100%}=0.32%$, $V_{90%}=3.33%$, $V_{80%}=7.71%$, $V_{50%}=23.55%$ in the first treatment plan. In case of rectum, the average of absolute volume in first plan was 117.9 cc. However, the average of really treated volume was 79.2 cc. In case of CTV, the 100% prescription dose area didn't satisfy even though the margin for PTV was 5 mm because of the variation of rectal and bladder volume. Conclusion : There was no case that the value from average of five fractions is over the dosimetric limits. However, dosimetric errors of rectum and bladder in each fraction was significant. Therefore, the precise delivery is needed in case of prostate SBRT. The real-time tracking and adaptive plan is necessary to meet the precision delivery.

• Journal of Korean Society of Forest Science
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• v.33 no.1
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• pp.33-58
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• 1977

A bark comprises about 10 to 20 percents of a typical log by volume, and is generally considered as an unwanted residue rather than a potentially valuable resourses. As the world has been confronted with decreasing forest resources, natural resources pressure dictate that a bark should be a raw material instead of a waste. The utilization of the largely wasted bark of genus Pinus, Quercus, and Populus grown in Korea can be enhanced by learning its physical and mechanical properties. However, the study of tree bark grown in Korea have never been undertaken. In the present paper, an investigative study is carried out on the bark of three genus, eleven species representing not only the major bark trees but major species currently grown in Korea. For each species 20 trees were selected, at Suweon and Kwang-neung areas, on the same basis of the diameter class at the proper harvesting age. One $200cm^2$ segment of bark was obtained from each tree at brest height. Physical properties of bark studied are: bark density, moisture content of green bark (inner-, outer-, and total-bark), fiber saturation point, hysteresis loop, shrinkage, water absorption, specific heat, heat of wetting, thermal conductivity, thermal diffusivity, heat of combustion, and differential thermal analysis. The mechanical properties are studied on bending and compression strength (radial, longitudinal, and tangential). The results may be summarized as follows: 1. The oven-dry specific gravities differ between wood and bark, further more even for a given bark sample, the difference is obersved between inner and outer bark. 2. The oven-dry specific gravity of bark is higher than that of wood. This fact is attributed to the anatomical structure whose characters are manifested by higher content of sieve fiber and sclereids. 3. Except Pinus koraiensis, the oven-dry specific gravity of inner bark is higher than that of outer bark, which results from higher shrinkage of inner bark. 4. The moisture content of bark increases with direct proportion to the composition ratio of sieve components and decreases with higher percent of sclerenchyma and periderm tissues. 5. The possibility of determining fiber saturation point is suggested by the measuring the heat of wetting. With the proposed method, the fiber saturation point of Pinus densiflora lies between 26 and 28%, that of Quercus accutissima ranges from 24 to 28%. These results need be further examined by other methods. 6. Contrary to the behavior of wood, the bark shrinkage is the highest in radial direction and the lowest in longitudinal direction. Quercus serrata and Q. variabilis do not fall in this category. 7. Bark shows the same specific heat as wood, but the heat of wetting of bark is higher than that of wood. In heat conductivity, bark is lower than wood. From the measures of oven-dry specific gravity (${\rho}d$) and moisture fraction specific gravity (${\rho}m$) is devised the following regression equation upon which heat conductivity can be calculated. The calculated heat conductivity of bark is between $0.8{\times}10^{-4}$ and $1.6{\times}10^{-4}cal/cm-sec-deg$. $$K=4.631+11.408{\rho}d+7.628{\rho}m$$ 8. The bark heat diffusivity varies from $8.03{\times}10^{-4}$ to $4.46{\times}10^{-4}cm^2/sec$. From differential thermal analysis, wood shows a higher thermogram than bark under ignition point, but the tendency is reversed above ignition point. 9. The modulus of rupture for static bending strength of bark is proportional to the density of bark which in turn gives the following regression equation. M=243.78X-12.02 The compressive strength of bark is the highest in radial direction, contrary to the behavior of wood, and the compressive strength of longitudinal direction follows the tangential one in decreasing order.

• Economic and Environmental Geology
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• v.8 no.3
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• pp.117-124
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• 1975

Wet chemical analysis (for $MnO_2$, MnO, and $H_2O$(+)) and electron microprobe analysis (for $Fe_2O_3$ and PbO) give $MnO_2$ 74.91, MnO 11.33, $Fe_2O_3$ (total Fe) 4.19, PbO 0.03, $H_2O$ (+) 9.46, sum 99.92%. 'Available oxygen determined by oxalate titration method is allotted to $MnO_2$ from total Mn, and the remaining Mn is calculated as MnO. Traces of Ba, Ca, Mg, K, Cu, Zn, and Al were found. Li and Na were not found. The existence of (OH) is verified from the infrared absorption spectra. The analysis corresponds to the formula $Mn^{4+}{_{4.85}}(Mn^{2+}{_{0.90}}Fe^{3+}{_{0.30}})_{1.20}O_{8.09}(OH)_{5.91}$, on the basis of O=14, 'or ideally $Mn^{4+}{_{5-x}}(Mn^{2+},Fe^{3+})_{1+x}O_{8}(OH)_{6}$ ($x{\approx}0.2$). X-ray single crystal study could not be made because of the distortion of single crystals. But the x-ray powder pattern is satisfactorily indexed by an orthorhombic cell with a 9.324, b 14.05, c $7.956{\AA}$., Z=4. The indexed powder diffraction lines are 9.34(s) (100), 7.09(s) (020), 4.62(m) (200, 121), 4.17(m) (130), 3.547(s) (112), 3.212(vw) (041), 3.101(s) (300), 2.597(w) (013), 2.469(m) (331), 2.214(vw)(420), 2.098(vw) (260), 2.014 (vw) (402), 1.863(w) (500), 1.664(w) (314), 1.554(vw) (600), 1.525(m) (601), 1.405(m) (0.10.0). DTA curve shows the endothermic peaks at $250-370^{\circ}C$ and $955^{\circ}C$. The former is due to the dehydration: and oxidation forming$(Mn,\;Fe)_2O_3$(cubic, a $9.417{\AA}$), and the latter is interpreted as the formation of a hausmannite-type oxide (tetragonal, a 5.76, c $9.51{\AA}$) from $(Mn,\;Fe)_2O_3$. Infrared absorption spectral curve shows Mn-O stretching vibrations at $515cm^{-1}$ and $545cm^{-1}$, O-H bending vibration at $1025cm^{-1}$ and O-H stretching vibration at $3225cm^{-1}$. Opaque. Reflectance 13-15%. Bireflectance distinct in air and strong in oil. Reflection pleochroism changes from whitish to light grey. Between crossed nicols, color changes from yellowish brown with bluish tint to grey in air and yellowish brown to grey through bluish brown in oil. No internal reflections. Etching reactions: HCl(conc.) and $H_2SO_4+H_2O_2$-grey tarnish; $SnCl_2$(sat.)-dark color; $HNO_3$(conc.)-grey color; $H_2O_2$-tarnish with effervescence. It is black in color. Luster dull. Cleavage one direction perfect. Streak brownish black to dark brown. H. (Mohs) 2-3, very fragile. Specific gravity 3.59(obs.), 3.57(calc.). It occurs as radiating groups of flakes, flower-like aggregates, colloform bands, dendritic or arborescent masses composed of fine grains in the cementation zone of the supergene manganese oxide deposits of the Janggun mine, Bonghwa-gun, southeastern Korea. Associated minerals are calcite, nsutite, todorokite, and some undetermined manganese dioxide minerals. The name is for the mine, the first locality. The mineral and name were approved before publication by the Commission on New Minerals and Mineral Names, I.M.A.