• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.14 no.3
• /
• pp.535-542
• /
• 1994

Remote sensing technique is based on the estimation of land surface characteristics from the measurement of the emitted radiation from the earth. The hydrologically related parameters studied using this approach include surface temperature, evapotranspiration, soil moisture, precipitation and snow. This study introduces a method for estimating moisture content of a bare soil from the observed and simulated brightness temperature. In a bare soil, microwave emission depends on moisture content, soil temperature, and surface roughness. The method is based on a radiative transfer model with some modifications of Fresnel reflection coefficient to take into account the effect of surface roughness. One smooth bare field and two fields with different surface roughness are prepared for the study. The results indicate that the effect of surface roughness is to increase the soil's brightness temperature and to reduce the slope of regression between brightness temperature and moisture contents.

• Journal of Radiation Protection and Research
• /
• v.26 no.1
• /
• pp.27-33
• /
• 2001

This study was performed to determine the effect of several herbs on radiation-induced apoptosis in jejunal crypt cells. Longyanrou(Euphoris longana), Suanzaoren(Zizyphus vulgaris), Yuanzhi(Polygala tenuifolia), Rensan(Panax ginseng), Fuling(Poria cocos), Muxiang (Saussurea lappa), Chuanxiong(Cnidium officinale), Baishaoyao(Paeonia lactifolia), Shengma (Cimicifuga heracleifolia), Chaihu (Bupleurum falcatum) and Dongchongxiacao ( Paecilomyces japonica) reduced the frequency of radiation-induced apoptosis(p<0.05). Although the mechanisms of this effect remain to be elucidated, these results indicated that Longyanrou, Suanzaoren, Yuanzhi, Rensan, Fuling, Muxiang, Chuanxiong, Baishaoyao, Shengma, Chaihu and Dongchongxiacao might be useful inhibitors of apoptosis, especially since these are relative nontoxic natural products.

• The Journal of Korean Society for Radiation Therapy
• /
• v.30 no.1_2
• /
• pp.177-183
• /
• 2018

Purpose : Volumetric Modulated Arc Therapy(VMAT) has the advantage of uniformly and precisely irradiating the tumor to the shape of the tumor while reducing the risk of radiation damage to normal tissues. such as brain cancer, head and neck cancer and prostate cancer, It is being used for treatment. The purpose of this study is to evaluate the usefulness of the Jaw-Tracking technique(JTT) in VMAT for brain and head and neck cancer. Materials and Methods : We selected eight patients with brain and head and neck cancer(4 Brain, 4 head and neck) who were treated with the VMAT treatment technique. Contouring information of the patient's tumor and normal organ was fused to the Rando phantom using the deformable registration of Velocity(Varian, USA). A treatment plan was developed using the Varian Eclipse(ver 15.5, Varian, USA) with the same patient actual beam parameters except for the use of jaw-tracking. As the evaluation index, the maximum dose and mean dose of target and OAR were compared and a portal dosimetry was performed for the treatment plan verification. Results : When using JTT, the relative dose of OAR decreased by 5.24 % and the maximum dose by 7.05 %, respectively, compared with the Static-Jaw technique(SJT). In the various OARs, the mean dose and maximum dose reduction ranges ranged from 0.01 to 3.16 Gy and from 0.12 to 6.27 Gy, respectively. In the case of the target, the maximum dose of GTV, CTV, PTV decreased by 0.17 %, 0.43 %, and 0.37 % in JTT, and the mean dose decreased by 0.24 %, 0.47 % and 0.47 %, respectively. Gamma analysis The JTT and SJT passing rates were $98{\pm}1.73%$ and $97{\pm}1.83%$ on the basis of 3 % / 3 mm, respectively. Comparing the doses of all OARs applied to the experiment, it was found that the use of JTT resulted in a significant decrease in dose due to additional jaw shielding besides MLC than SJT. Conclusion : In radiation therapy using VMAT treatment plan, we can apply JTT in the case of adjacent tumor and normal organs such as brain cancer and head and neck cancer, and in radiotherapy required large field and high energy caused increase leakage dose through MLC. It is considered that the target dose of PTV can be increased by lowering the dose of normal tissue surrounding the tumor.

• The Journal of Korean Society for Radiation Therapy
• /
• v.30 no.1_2
• /
• pp.153-160
• /
• 2018

Purpose : We retrospectively analyzed doses of each radiation therapy technique used in the treatment for left breast cancer patients after partial mastectomy through dose results for normalorgans and tumor volume to use this as a clinical reference for radiation therapy of domestic left breast cancer patients. Materials and Methods : 40 patients who underwent partial mastectomy on left breast cancer were classified in 3 treatment methods. The treatment plan was evaluated by HI(homogeneity index), $D_{95%}$, and CI(conformity index), and the $V_{hot}$ for gross tumor volume and clinical target volume of each treatment method. In Cyberknife treatment, tumor volume was the same as high dose volume in the other techniques, so no consideration was given to clinical target volume. Treatment plan evaluation for normal organs were evaluated by mean dose on ipsilateral lung, heart, left anterior descending artery, opposite breast and lung, and non-target tissue. Result : Treatment with volumetric arc radiotherapy(VMAT) showed $95.84{\pm}0.75%$ of $D_{95%}$ on the clinical target volume, significantly higher than that of 3D-CRT. The $D_{95%}$ value of the total tumor volume was slightly higher than the other treatments. In Cyberknife treatment, the dose to the normal organs was significantly lower than other treatments. Overall, the maximum dose and mean dose to the heart were $26.2{\pm}6.12Gy$ and $1.88{\pm}0.2Gy$ in VMAT treatment and $20.25{\pm}9.35Gy$ and $1.04{\pm}0.19Gy$ in 3D-CRT therapy, respectively. Conclusion : In comparison on 3D-CRT and VMAT, most of the dosimetric parameters for the evaluation of the treatment plan showed similar values, so that there is no significant difference in treatment plan evaluation. It is possible to select the treatment method according to the patient's anatomical structure or possibility of breath control. Cyberknife treatment is very useful treatment for normal organs because of its accurate dose exposure to the tumor volume However, it has restrictions to treat the local area, to have relatively long treatment time and to involve invasive procedure.

• Journal of radiological science and technology
• /
• v.27 no.4
• /
• pp.17-21
• /
• 2004

With advancement of the medical imaging technology, the dynamic pelvic MRI (magnetic resonance imaging) has been introduced and used for dynamic MR defecography to improved diagnosis of the patients. At the early stage of its use, it was mostly used to diagnose enterocele or cystocele, then its use was extended to diagnose the organ prolapse and other dysfunctional pelvis organs. There now have been many reports of other diseases such as the functional constipation and others. This paper introduces the pelvis MRI and the dynamic MR defecography and reports the future trend in their clinical applications. Until recently, the studies with pelvic MRI were mostly focused on observing the movement of the pelvis in the supine position. Yang and 26 others reported good result in observing the patients with the pelvic organ prolapse by using the pubococcygeal line as the anatomical index. Using the fast gradient recalled acquisition (fast GRASS), they compared cystocoele, genitourinary prolapse, enterocoele and rectocoele with the control group. Kruyt et al. observed the posterior compartment and reported that MRI was more helpful than the fluoroscopy. Healy et al. applied the dynamic MRI test on the patients with constipation or incontinence as well as the control group without those symptoms. Since then, MRI technology has further advance by Lienemann, who was able to attain the more detailed images using the fast T2 weighted turbo spin echo technology, and others. If its limitation in diagnosing intussusception and the like, since the observation can be made only from the supine position, can be overcome with open MR or others, it is envisages that the method can eventually replace the radiological defecography.

• Journal of Veterinary Clinics
• /
• v.21 no.3
• /
• pp.286-290
• /
• 2004

Cytogenetic and hematological analysis was performed in peripheral blood of pig in the vicinity of Yeonggwang nuclear power station and control area. The frequency of micronuclei (MN) in peripheral blood lymphocytes from pig was used as a biomarker of radiobiological effects resulting from exposure to environmental radiation. An estimated dose of radiation was calculated by a best fitting linear-quadratic model based on the radiation-induced MN formation from the swine lymphocytes exposed in vitro to radiation over the range from 0 Gy to 4 Gy. MN rates in lymphocytes of pig from Yeonggwang nuclear power station and control area were 10.60/1,000 and 11.10/1,000, respectively. There were no significant differences in MN frequencies and hematological values in pig between Yeonggwang and control area. The study indicates that the MN assay in lymphocyte of pig is a rapid, sensitive and accurate method that can be used to monitor a large population exposed to radiation.

• Journal of Radiation Protection and Research
• /
• v.33 no.3
• /
• pp.99-104
• /
• 2008

According to the increase in the use of radiotherapy to cancer patients, many approaches have been tried to develop new agents for the protection of surrounding normal tissues. However, it is still few applied in the clinic as a radioprotector. We aim to find a representative parameter for radioprotection to easily predict the activity of in vivo experiment from the results of in vitro screening. The polysaccharide extracted from Panax ginseng was used in this study because the immunostimulator has been regarded as one of the radioprotective agent category and was already reported having a promising radioprotective activity through the increase of hematopoietic cells and the production of several cytokines. Mitogenic activity, AK cells activity and nitric oxide production were monitored for the in vitro immunological assay, and endogenous colony-forming unit (e-CFU) was measured as in vivo radioprotective parameter. The immunological activity was increased by the galactose contents of ginseng polysaccharide dependently. The result of this study suggests that mitogenic activity of splenocytes demonstrated a good correlation with in vivo radioprotective effect, and may be used as a representative parameter to screen the candidates for radioprotector.

• Journal of Oral Medicine and Pain
• /
• v.25 no.3
• /
• pp.293-303
• /
• 2000

앵글씨 분류에 따른 최대개구시 하악의 수직 변위에 대한 차이를 확인하고, 수직 하악운동에 영향을 주는 골격요소를 확인하기 위하여, 측두하악관절 및 저작계 이상에 대한 증상 및 병력이 없으며 발치 및 교정치료의 경험이 없는 광주지역 대학에 재학중인 학생들을 대상으로, 앵글씨 구치부 관계에 근거하여 1급군(남:30명, 여:49명), 2급군(남:18명, 여:24명)과 3급군(남:18명, 여:33명)으로 분류하여 총 172명(연령 범주:20-30세)의 학생을 선택하였다. 전남대학교 병원 구강내과에서 사용하는 계측용자를 이용하여 최대 개구시 상하악 중절치 절단면간의 거리를 측정하였다. 대상자들의 진단모형을 만들어 상하악궁 길이와 폭경를 측정하였다. 대상자들에 대한 두부 규격방사선 사진을 촬영, 작도하고 방사선학적 지표를 계측, 비교분석하였다. 앵글씨 분류 1급군, 2급군 그리고 3급군 절치간 최대개구량은 3급군이 가장 컸으며 모든 군에서 남자가 여자보다 컸다. 구치간 최대개구량은 앵글씨 분류 1급군, 2급군 그리고 3급군에서 각 군간의 유의한 차이는 없었으나, 모든 군에서 남자가 더 컸다. 앵글씨 분류 1급군과 2급군의 하악운동에서 총 하악골 길이, 하악지 길이, 하악 하연부 길이 그리고 상악궁 폭경이 변수로 나타났으며, 상하악궁 길이와는 역상관관계를 나타내었다. 앵글씨 분류 3급군의 하악운동에서 상하악궁 길이와 안면 부길이가 1급군과 2급군과는 다른 중요한 변수로 나타났으며, 상악궁의 폭경과는 역상관관계를 나타내었다. 이상의 결과로 보아 앵글씨 분류 각 군에서 하악개구운동은 안면 골격구조의 영향을 받으며, 각 군간에 영향을 주는 안면 골격 요소들은 차이가 있었다. 따라서 이러한 골격적 요소들은 개구량 개선을 위한 진단과 치료시 고려되어야 할 것으로 사료된다.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.29 no.3
• /
• pp.272-279
• /
• 2013

The concept of implant stability was basically originated from the relative condition of bone-implant interface and has some meanings for evaluation of that interface. In addtion, it has been used for the investigation of initial bone healing process after fixture installation because a degree of micromotion around interface can affect unfavorable clinical results. The purpose of this study is to investigate the mode of initial bone healing from fixture installation through prospective trial. Thirty fixtures were consecutively installed in mandibles of 26 patients with single tooth loss area and then healing abutment were secured for one-stage surgery meothod. Resonance frequency analysis was performed with one week interval during 12 weeks and periapical radiographs were taken at each month. Although marginal bone level change was not shown through observation period (P>0.05), statistical difference of implant stability was shown through 4 and 6 week (P<0.05) and was not shown after 6 week (P>0.05) according to the bone quality. Initial bone healing process is a successive process of bone resorption and favorable bone healing result might be postulated at 4 week interval after installation through RFA.

• Radiation Oncology Journal
• /
• v.4 no.2
• /
• pp.99-105
• /
• 1986

Optimal balance between control probability and risk of complication is emphasized even in present time, Although certain incidence of intestinal injury is accepted as an inevitable consequence after abdominopelvic irradiation, these complications still remain as problems. 60 mice were irradiated with 250 kVp orthovoltage x-ray machine and $200rad{\times}5/wk$ regimen. Histpathologic findings of colorectum and the relationship with occult blood test were analyzed and possible tolerable dose which would be safe from permanent complication was also estimated. Followings are the results: Mild mucosal and submucosal edema were observed in 1,000 rad irradiated group. Congestion of small vessels was prominent in 2,000 rad irradiated group and infiltration of inflammatory cells was observed in 3,000 rad irradiated group. Denuded mucosa was observed in 3,000 rad irradiated group. Occult blood test is not a proper indicator for rectal denuding or rectal ulcer, but our results suggest the possibility of using this as a relative scale of intestinal damage. Mitotic figures of crypt cells were observed even in 5,000 rad irradiated group, these suggest that the repair capacity of crypt cells are still functioning.