• Proceedings of the Korean Society of Medical Physics Conference
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• 2003.09a
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• pp.37-37
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• 2003

목적 : 일반적으로 세기조절방사선치료 조사면의 작은 조각 크기에 대해, 이상적인 플루언스 지도 혹은 치료계획장치로부터의 최적화된 결과에 가까운 선량분포에서 더 좋은 leaf sequence를 얻을 수 있다. 한편, 치료중 장기의 움직임이 가장 작은 조각 크기의 선택을 방해하는 문제는 항상 존재한다. 게다가, 전통적인 정지 조사면과 달리 표적이 움직이는 동안 조사면 자체도 움직이므로 움직이는 표적에 대한 세기조절방사선치료의 경우에서 적절한 표적 마진에 관한 질문이 제기되어왔다. 따라서, 이 연구에서는 조각 크기에 대한 치료중 표적 움직임의 효과를 연구하였다. 대상 및 방법 : 세기조절방사선치료 플루언스 지도에 대해, 다양한 크기 - 0.5$\times$0.5, 1.0$\times$1.0, $1.5\times$1.5, 2.0$\times$2.0, 3.0$\times$3.0, 4.0$\times$4.0, 5.0$\times$5.0 $ extrm{cm}^2$ - 의 정사각형 패턴들을 설계하였고, Leaf sequence 는 step-and-shoot 빔 전달 방법을 이용하였다. 인접 조각들 사이의 세기 비율은 0.2, 0.4, 0.6, 0.8, 1.0로 하였고, 표적 움직임은 범위가 0.5-2.0 cm인 사인곡선 형태로 가정하였다. 움직임 묘사를 위해 동적 leaf 의 움직임이 표적의 움직임 을 반영하도록 계산되었고 움직임의 효과를 분석하기 위해 필름선량측정을 수행하였다. 결과 : 인접 조각의 세기 비율은 모든 경우에서 저하되었고, 호흡 진폭의 반보다 작은 조각 크기에 대한 선량분포는 임상적으로 유의할만큼 저하된 세기 지도를 보였다. 조각에 대해 방사선 조사시간의 두 호흡주기이상에 대해서는, 표적 마진 주위의 선량분포가 통상적인 정지 조사면에서와 같았다. 결론 : 플루언스 지도에서 세기조절방사선치료 조각의 최소 크기는 치료중 장기 움직임을 고려한 후 선택되어야 한다. 조각에 대한 방사선 조사시간의 두 호흡주기이상에 대해서는, 표적 마진을 기존의 정지 조사면과 같게 정의할 수 있었다.

• Progress in Medical Physics
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• v.13 no.1
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• pp.15-20
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• 2002

Optimum field size for the whole body stereotactic radiosurgery was studied. Dose distributions from the various sizes of targets (diameter 1cm to 7cm, icm interval) were used for this study. Planing scores, expressed as the Target Coverage Index (TCI), were calculated for various target Margin ranged 0cm to 0.5cm. Highest scores were obtained for no Margin to the target size. The target Margin -0.5cm to 0cm to the target showed best TCI the cases of the target size larger than 6cm diameter. No Margin or 0.5cm Margin generated best TCI for less than 2cm cases. Prescription to 80~90% gives best results.

• Economic and Environmental Geology
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• v.48 no.3
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• pp.241-246
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• 2015

Helicobacter pylori is an important transmissible human pathogen found on the luminal surface of the gastric epithelium. The organism can persist in the stomach indefinitely and causes gastroduodenal inflammation that may proceed to atrophic gastritis, peptic ulcer, gastric MALT lymphoma, and gastric cancer. Standard triple therapy which consists of proton pump inhibitor (PPI) plus two antibiotics (amoxicillin and clarithromycin) is now generally used in Korea, however, eradication rates of H. pylori has been decreasing due to increasing antibiotic resistance. In this review, current second-line treatment regimens, difficult problems on treatment, necessity of local target therapy, applicability of clay minerals as a drug delivery system (DDS), and a new therapeutic strategy and its study plans will be discussed.

• Journal of radiological science and technology
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• v.35 no.3
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• pp.255-263
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• 2012

The aim of this study was to evaluate the patient specific quality assurance (QA) results of intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) through the AAPM Task Group Report 119. Using the treatment planning system, both IMRT and VMAT treatment plans were established. The absolute dose and relative dose for the target and OAR were measured by using an ion chamber and the bi-planar diode array, respectively. The plan evaluation was used by the Dose volume histogram (DVH) and the dose verification was implemented by compare the measured value with the calculated value. For the evaluation of plan, in case of prostate, both IMRT and VMAT were closed the goal of target and OARs. In case of H&N and Multi-target, IMRT was not reached the goal of target, but VMAT was reached the goal of target and OARs. In case of C-shape(easy), both were reached the goal of target and OARs. In case of C-shape(hard), both were reached the goal of target but not reached the goal of OARs. For the evaluation of absolute dose, in case of IMRT, the mean of relative error (%) between measured and calculated value was $1.24{\pm}2.06%$ and $1.4{\pm}2.9%$ for target and OAR, respectively. The confidence limits were 3.65% and 4.39% for target and OAR, respectively. In case of VMAT the mean of relative error was $2.06{\pm}0.64%$ and $2.21{\pm}0.74%$ for target and OAR, respectively. The confidence limits were 4.09% and 3.04% for target and OAR, respectively. For the evaluation of relative dose, in case of IMRT, the average percentage of passing gamma criteria (3mm/3%) were $98.3{\pm}1.5%$ and the confidence limits were 3.78%. In case of VMAT, the average percentage were $98.2{\pm}1.1%$ and the confidence limits were 3.95%. We performed IMRT and VMAT patient specific QA using TG-119 based procedure, all analyzed results were satisfied with acceptance criteria based on TG-119. So, the IMRT and VMAT of our institution was confirmed the accuracy.

• Korean Journal of Head & Neck Oncology
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• v.21 no.2
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• pp.151-157
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• 2005

목적: 다양한 발생부위에서 발생한 두경부종양을 대상으로 3차원 입체조형치료를 시도하여 표적체적 내 선량균일성과 주변장기의 선량분포변하를 알아보고자 하였다. 대상 및 방법: 1995년 1월부터 1996년 12월까지 3차원 입체조형치료를 시행 받은 38명에 분석을 시행하였다. 3차원 입체조형 치료는 동일평면 또는 비동일평면상에서 4개에서 14개의 조사면 수로 시행되었다. 3차원 입체조형치료계획시 표적 체적에 $50{\sim}82Gy$의 선량을 처방하였고, 이하선 안구, 척수, 측두하악관절 등을 보호하고자 하였다. 3차원 입체조형치료 계획을 기존의 2차원 치료계획과 비교하기 위하여 표적체적과 주변정상자기의 선량체적히스토그램, 평균선량, 표적체적 내에서 처방선량의 $95{\sim}105%$의 선량이 분포하는 체적을 비교하였다 치료계획에서 실제 치료시까지 소용되는 비용효과를 비교하였다. 대상환자의 평균추적기간은 34개월이었다. 결 과: 3차원 입체조형시료는 2차원 치료에 비해서 표적체적내 평균선량이 평균 10% 증가하였고, 주변정장기에 조사되는 방사선량이 현저히 감소됨을 관찰할 수 있었고 표적체적에 대한 등선량 곡선 분포가 우수함을 관찰할 수 있었다. 결 론: 3차원 입체조형치료는 두경부종양에서 표적체적의 선량 균일성이 증가하였고, 주변장기의 보존이 가능할 것으로 생각되었다. 따라서 본 저자들은 3차원 입체조형치료가 두경부종양에서 국소제어율과 무질병생존율 향상에 기여할 것으로 생각하였다.

• Progress in Medical Physics
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• v.25 no.3
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• pp.128-138
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• 2014

In gated radiation therapy (gRT), due to residual motion, beam delivery is intended to irradiate not only the true extent of disease, but also neighboring normal tissues. It is desired that the delivery covers the true extent (i.e. clinical target volume or CTV) as a minimum, although target moves under dose delivery. The objectives of our study are to validate if the intended dose is surely delivered to the true target in gRT and to quantitatively understand the trend of dose delivery on it and neighboring normal tissues when gating window (GW), motion amplitude (MA), and CTV size changes. To fulfill the objectives, experimental and computational studies have been designed and performed. A custom-made phantom with rectangle- and pyramid-shaped targets (CTVs) on a moving platform was scanned for four-dimensional imaging. Various GWs were selected and image integration was performed to generate targets (internal target volume or ITV) for planning that included the CTVs and internal margins (IM). The planning was done conventionally for the rectangle target and IMRT optimization was done for the pyramid target. Dose evaluation was then performed on a diode array aligned perpendicularly to the gated beams through measurements and computational modeling of dose delivery under motion. This study has quantitatively demonstrated and analytically interpreted the impact of residual motion including penumbral broadening for both targets, perturbed but secured dose coverage on the CTV, and significant doses delivered in the neighboring normal tissues. Dose volume histogram analyses also demonstrated and interpreted the trend of dose coverage: for ITV, it increased as GW or MA decreased or CTV size increased; for IM, it increased as GW or MA decreased; for the neighboring normal tissue, opposite trend to that of IM was observed. This study has provided a clear understanding on the impact of the residual motion and proved that if breathing is reproducible gRT is secure despite discontinuous delivery and target motion. The procedures and computational model can be used for commissioning, routine quality assurance, and patient-specific validation of gRT. More work needs to be done for patient-specific dose reconstruction on CT images.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.251-251
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• 1994

1차년도에서 이미 확립한 다양한리포좀의 제조 방법에 따라간세포를표 적하기 위해 이들 리포좀의 조성에 galactocercbroside를 함유시켜 targeted liposomes을 제조하였다. 표적리포좀의 제조 방법에 따른 봉합율 (cncapsulation)과 안정성을 조사했을 때, freezing-thawing 과정을 거친 리포좀이 encapsulation 과 stability가 가장 뛰어남을 알 수 있었다. In vitro 간세포 표적능력을 in vitro cell culture system에서 간세포 cell line (Hep G2, 2.2.15과 다른 cell line (Vero E6, J82)에 대한 표적리포좀과 control liposomes의 uptake를 FTTC 또는 CF 형광으로 측정했을 때, 표적리포좀이 간세포 cell line에 더 많이 uptake하는 것을 알았다. In vivo 실험에서는 6 - 8 주령의 mouse tail vain에 표적리포좀과 control liposomes을 주사하여 각 장기에 존재하는 리포좀의 양을 형광으로 측정했을 때, 표적리포좀 (targetcd liposomes)이 다른 장기에 비해 liver에 선택적으로 많이 분포함을 알수있었다. 또한 간암의 효과적인 치료를 위해 간세포와 암세포를 동시에 표적할 수는 double targeting liposomes을 design 하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.12
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• pp.2395-2400
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• 2016

Conventional drug carriers such as liposomes, nanoparticles, polymer micelles, polymeric conjugate and lipid microemulsion for cancer chemotherapy shield normal tissues from toxic drugs to treat cancer cells in tumors. However, inaccurate tumor targeting uncontrolled drug release from the carriers and unwanted accumulation in healthy sites can limit treatment efficacy with current conventional drug carriers with insufficient concentrations of drugs in the tumors and unexpected side effects as a result. Sickle red blood cells show natural tumor preferential accumulation without any manipulation due to the adhesive interaction between molecular receptors on the membrane surface and counter-receptor on endothelial cells. In addition, structural changes of microvascular in tumor sites enhances polymerization of sickle red blood cells. In this research, we examined the use of sickle red blood cells as a new drug carrier with novel tumor targeting and controlled release properties to quantify its therapeutic effects.

• Journal of radiological science and technology
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• v.34 no.1
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• pp.51-58
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• 2011

The aim of the study is to analyze the dose delivery error depending on the depth variation according to target positions and arc trajectories by comparing the simulated treatment planning with the actual dose delivery in conformal arc therapy. We simulated the conformal arc treatment planning with the three target positions (center, 2.5 cm, and 5 cm in the phantom). For the experiments, IMRT body phantom (I’mRT Phantom, Wellhofer Dosimetry, Germany) was used for treatment planning with CT (Computed Tomography, Light speed 16, GE, USA). The simulated treatment plans were established by three different target positions using treatment planning system (Eclipse, ver. 6.5, VMS, Palo Alto, USA). The radiochromic film (Gafchromic EBT2, ISP, Wayne, USA) and dose analysis software (OmniPro-IMRT, ver. 1.4, Wellhofer Dosimetry, Germany) were used for the measurement of the planned arc delivery using 6 MV photon beam from linear accelerator (CL21EX, VMS, Palo Alto, USA). Gamma index (DD: 3%, DTA: 2 mm) histogram and dose profile were evaluated for a quantitative analysis. The dose distributions surrounded by targets were also compared with each plans and measurements by conformity index (CI), and homogeneity index (HI). The area covered by 100% isodose line was compared to the whole target area. The results for the 5 cm-shifted target plan show that 23.8%, 35.6%, and 37% for multiple conformal arc therapy (MCAT), single conformal arc therapy (SCAT), and multiple static beam therapy, respectively. In the 2.5 cm-shifted target plan, it was shown that 61%, 21.5%, and 14.2%, while in case of center-located target, 70.5%, 14.1%, and 36.3% for MCAT, SCAT, and multiple static beam therapy, respectively. The values were resulted by most superior in the MCAT, except the case of the 5 cm-shifted target. In the analysis of gamma index histogram, it was resulted of 37.1, 27.3, 29.2 in the SCAT, while 9.2, 8.4, 10.3 in the MCAT, for the target positions of center, shifted 2.5 cm and 5 cm, respectively. The fail proportions of the SCAT were 2.8 to 4 times as compared to those of the MCAT. In conclusion, dose delivery error could be occurred depending on the target positions and arc trajectories. Hence, if the target were located in the biased position, the accurate dose delivery could be performed through the optimization of depth according to arc trajectory.

• Radiation Oncology Journal
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• v.22 no.2
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• pp.77-90
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• 2004

Purpose: The purpose of this review Is to provide an update on novel radiation treatments for head and neck cancer Recent Findings: Despite the remarkable advances In chemotherapy and radiotherapy techniques, the management of advanced head and neck cancer remains challenging. Epidermal growth factor receptor (EGFR) Is an appealing target for novel therapies In head and neck cancer because not only EGFR activation stimulates many important signaling pathways associated with cancer development and progression, and importantly, resistance to radiation. Furthermore, EGFR overexpression Is known to be portended for a worse outcome in patients with advanced head and neck cancer. Two categories of compounds designed to abrogate EGFR signaling, such as monoclonal antibodies (Cetuxlmab) and tyrosine kinase inhibitors (ZD1839 and 051-774) have been assessed and have been most extensively studied In preclinical models and clinical trials. Additional TKIs In clinical trials include a reversible agent, Cl-1033, which blocks activation of all erbB receptors. Encouraging preclinical data for head and neck cancers resulted In rapid translation Into the clinic. Results from Initial clinical trials show rather surprisingly that only minority of patients benefited from EGFR inhibition as monotherapy or In combination with chemotherapy. In this review, we begin with a brief summary of erbB- mediated signal transduction. Subsequently, we present data on prognostic-predictive value of erbB receptor expression in HNC followed by preclinlcal and clinical data on the role of EGFR antagonists alone or in combination with radiation In the treatment of HNC. Finally, we discuss the emerging thoughts on resistance to EGFR biockade and efforts In the development of multiple-targeted therapy for combination with chemotherapy or radiation. Current challenges for investigators are to determine (1 ) who will benefit from targeted agents and which agents are most appropriate to combine with radiation and/or chemotherapy, (2) how to sequence these agents with radiation and/or cytotoxlc compounds, (3) reliable markers for patient selection and verification of effective blockade of signaling in vivo, and (4) mechanisms behind intrinsic or acquired resistance to targeted agents to facilitate rational development of multi-targeted therapy, Other molecuiar-targeted approaches In head and neck cancer were briefly described, Including angloenesis Inhibitors, farnesyl transferase inhibitors, cell cycle regulators, and gene therapy Summary: Novel targeted theraples are highly appealing in advanced head and neck cancer, and the most premising strategy to use them Is a matter of intense Investigation.