• Journal of Electrical Engineering and Technology
• /
• 제9권5호
• /
• pp.1724-1728
• /
• 2014

Heat sink has been used to help an electrical device operate in normal temperature condition. But heat sink radiates unwanted electromagnetic wave, which may cause electromagnetic interference problem. A resistance loaded grounding technique is proposed to reduce electromagnetic wave radiation by a heat sink. Numerical simulations are accomplished to find optimal loading resistance. Also electromagnetic fields radiated by from a heat sink are measured and compared with the simulation results. The test results verify the usefulness of the proposed technique.

• 대한방사선치료학회지
• /
• 제2권1호
• /
• pp.127-130
• /
• 1987

• 한국의학물리학회:학술대회논문집
• /
• 한국의학물리학회 2002년도 Proceedings
• /
• pp.138-140
• /
• 2002

The spinal cord dose is the one of the limiting factor for the radiation treatment of the head & neck (H&N) or the thorax region. Due to the fact that the cord is the elongated shaped structure, it is not an easy task to maintain the cord dose within the clinically acceptable dose range. To overcome this problem, the spinal cord partial block technique (PBT) with the dynamic Multi-Leaf Collimator (dMLC) has been developed. Three dimension (3D) conformal beam directions, which minimize the coverage of the normal organs such as the lung and the parotid gland, were chosen. The PBT field shape for each field was designed to shield the spinal cord with the dMLC. The transmission factors were determined by the forward calculation method. The plan comparisons between the conventional 3D conformal therapy plan and the PTB plan were performed to evaluate the validity of this technique. The conformity index (CI) and the dose volume histogram (DVH) were used as the plan comparison indices. A series of quality assurance (QA) was performed to guarantee the reliable treatment. The QA consisted of the film dosimetry for the verification of the dose distribution and the point measurements. The PBT plan always generated better results than the conventional 3D conformal plan. The PBT was proved to be useful for the H&N and thorax region.

• Journal of Radiation Protection and Research
• /
• 제11권1호
• /
• pp.83-89
• /
• 1986

High energy radiation therapy using accelerator or radioioisotope teletherapy unit is now one of the most important modality in the field dealing with human malignant tumor. It's successful technology overcomes incurable disease to change into curable disease not only by the improvement of clinical technique but also by the development of radiation physics and biology. The author presented the principles of radiation therapy by means of basic knowledge of medicine. physics and biology, described the various ways to improve the result of radiation therapy, and reviewed recent status of radiotherapy field in Korea.

• Journal of Yeungnam Medical Science
• /
• 제25권2호
• /
• pp.85-91
• /
• 2008

Intensity-modulated radiation therapy (IMRT) is believed to be one of the best radiation treatment techniques. IMRT is able to deliver fatal doses of radiation to the tumor region with minimal exposure of critical organs. It is essential to have a comprehensive quality assurance program to assure precision and accuracy in treatment, due to the character of IMRT. We applied quality assurance technique to the Eclipse treatment planning system and sought to determine its effectiveness in patient treatment planning. An acrylic phantom, film, and an ionization chamber were used in this study.

• 한국의학물리학회지:의학물리
• /
• 제31권3호
• /
• pp.124-134
• /
• 2020

Here we review the evolutionary history of radiation therapy technology through the festschrift of articles in celebration of the 30th anniversary of Korean Society of Medical Physics (KSMP). Radiation therapy technology used in clinical practice has evolved over a long period of time. Various areas of science, such as medical physics, mechanical engineering, and computer engineering, have contributed to the continual development of new devices and techniques. The scope of this review was restricted to two areas; i.e., output energy production and functional development, because it is not possible to include all development processes of this technology due to space limitations. The former includes the technological transition process from the initial technique applied to the first model to the latest technique currently used in a variety of machines. The latter has had a direct effect on treatment outcomes and safety, which changed the paradigm of radiation therapy, leading to new guidelines on dose prescriptions, innovation of dose verification tools, new measurement methods and calculation systems for radiation doses, changes in the criteria for errors, and medical law changes in all countries. Various complex developments are covered in this review. To the best of our knowledge, there have been few reviews on this topic and we consider it very meaningful to provide a review in the festschrift in celebration of the 30th anniversary of the KSMP.

• 대한안전경영과학회지
• /
• 제17권1호
• /
• pp.125-130
• /
• 2015

Techniques, using physical wedge filter and using dynamic wedge filter and FIF(Field in Field) and ISCT(Irregular Surface Compensating Technique), have been developed according to progress of radiation therapy of breast cancer. Measurement of dose was done to judge the usefulness of technique using three cases, non tissue loss after breast conserving operating and tissue loss after breast conserving operating and mastectomy. Dose indexes of breast tissue, CI (Conformity Index), HI (Homogeneity Index) and QOC (Quality of Coverage), dose index of skin, or dose indexes of lung, volume of 50 percent dose and 20 percent dose were estimated and compared. Using dynamic wedge filter is useful plan at non tissue loss allowing for high dose of lung. FIF and ISCT are useful plan at tissue loss. ISCT is useful plan at mastectomy. Henceforth, we need to apply to valid plan and body type and thorax size.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권17호
• /
• pp.7401-7405
• /
• 2014

Background: Postoperative chemoradiotherapy is accepted as standard treatment for stage IB-IV, M0 gastric cancer. Radiotherapy (RT) planning of gastric cancer is important because of the low radiation tolerance of surrounding critical organs. The purpose of this study was to compare the dosimetric aspects of 2-dimensional (2D) and 3-dimensional (3D) treatment plans, with the twin aims of evaluating the adequacy of 2D planning fields on coverage of planning target volume (PTV) and 3D conformal plans for both covering PTV and reducing the normal tissue doses. Materials and Methods: Thirty-six patients with stage II-IV gastric adenocarcinoma were treated with adjuvant chemoradiotherapy using 3DRT. For each patient, a second 2D treatment plan was generated. The two techniques were compared for target volume coverage and dose to normal tissues using dose volume histogram (DVH) analysis. Results: 3DRT provides more adequate coverage of the target volume. Comparative DVHs for the left kidney and spinal cord demonstrate lower radiation doses with the 3D technique. Conclusions: 3DRT produced better dose distributions and reduced radiation doses to left kidney and spinal cord compared to the 2D technique. For this reason it can be predicted that 3DRT will result in better tumor control and less normal tissue complications.

• 대한방사선방어학회:학술대회논문집
• /
• 대한방사선방어학회 2011년도 춘계 학술발표회 및 심포지엄
• /
• pp.80-81
• /
• 2011

• 대한방사선치료학회지
• /
• 제29권1호
• /
• pp.27-35
• /
• 2017

목 적: 왼편 유방암 환자의 경우 오른편 유방암 환자보다 심장과 폐 등 정상장기에 불필요한 선량이 일부 조사됨에 따라 부작용이 우려되고 있다. 이를 줄이기 위해 DIBH기법을 시행하고 있다. Conventional Radiation Therapy, Intensity Modulated Radiation Therapy, Volumetric Modulated Arc Therapy의 치료계획 방법에 따라 쇄골상 림프절과 내유 림프절을 포함한 왼편 유방암의 경우 주변 장기의 선량 값을 비교 평가하고자 한다. 대상 및 방법: 왼편 유방암 환자 중 쇄골상 림프절과 내유 림프절을 포함한 환자 8명을 대상으로 Free Breathing과 Deep inspiration breath-hold 기법을 적용하여 각각 CT-Simulation을 시행한다. 획득한 영상을 기반으로 체표윤곽을 그려 95 %$D_{max}$<110 %이 되도록 Conventional Radiation Therapy, Intensity Modulated Radiation Therapy, Volumetric Modulated Arc Therapy방법으로 계획하였다. Conventional Radiation Therapy는 쇄골상 림프절에 1문조사, 유방 부분에 접선 2문조사로 Field in Field 기법을 사용하였다. Intensity Modulated Radiation Therapy는 7개의 조사면으로 구성하였다. Volumetric Modulated Arc Therapy은 회전반경을 $290^{\circ}{\sim}179^{\circ}$으로 한 2 ARC를 이용하여 계획을 수행하였다. Eclipse의 선량체적용적을 참고하여 주변 정상 장기 선량을 분석하였다. 결 과: Deep inspiration breath-hold기법을 적용함으로 심장과 흉벽 사이의 간격은 평균 $1.6{\pm}0.6cm$ 증가하였다. 폐의 평균 선량은 $19.2{\pm}1.0Gy$로 Intensity Modulated Radiation Therapy에서 가장 작은 값이 나타났다. 심장의 $V_{30}(%)$은 $2.0{\pm}1.9$로 Intensity Modulated Radiation Therapy에서 가장 작은 값이었다. 좌전하행 관상동맥에서는 평균 선량이 $25.4{\pm}5.4Gy$로 Intensity Modulated Radiation Therapy에서 가장 작은 값으로 나타났다. 반대편 유방의 최대선량 값은 Intensity Modulated Radiation Therapy일 때 $29.7{\pm}4.3Gy$로 가장 작은 값으로 나타났다. 결 론: 주변 정상장기 선량의 값을 비교해 보았을 때, Intensity Modulated Radiation Therapy와 Volumetric Modulated Arc Therapy은 치료에 적용할 수 있는 값으로 나타났다. 이 중 Intensity Modulated Radiation Therapy가 적합한 치료계획 방법으로 사료된다.