• 제목/요약/키워드: external beam radiation

검색결과 155건 처리시간 0.031초

근접치료 시 외부 방사선 치료 전후의 MR 영상 비교분석 (Comparison Analysis of MR Images Before and After External Beam Radiotherapy in Brachytherapy)

  • 최은혜;백충석;이성용;변영식
    • 대한방사선치료학회지
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    • 제23권1호
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    • pp.7-12
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    • 2011
  • 목 적: 자궁경부암 환자의 방사선 치료는 일반적으로 외부 방사선 치료 후 근접치료를 시행하는데, 외부 방사선 치료 후 종양의 위치나 부피가 변화하므로 근접치료 시 이전의 MR 영상만을 참고하여 applicator 삽입을 할 경우 많은 오류가 발생할 수 있다. 이에 본원에서는 외부 방사선 치료 전후의 MR 영상 비교를 통해 근접치료 시 발생할 수 있는 applicator 삽입 오류를 분석하여 외부 방사선 치료 후 MR 영상의 유용성에 대해 알아보고자 하였다. 대상 및 방법: 2009년 1월부터 2010년 12월까지 Fletcher CT/MR applicator를 사용한 자궁경부암 환자 35명을 대상으로 외부 방사선 치료 전후에 촬영한 MR 영상을 비교하였다. 결 과: MR 영상 분석 결과 외부 방사선 치료 후 종양이 줄어들면서 전굴이었던 자궁이 후굴로 바뀌게 된 경우가 17.1%, tandem 삽입시 방향이나 길이 등이 잘못된 경우가 14.3%로 나타났다. 결 론: 외부 방사선 치료 후 MRI를 촬영하면 줄어든 종양과 함께 정확한 자궁의 위치와 길이를 확인할 수 있어 근접치료 시행 시 applicator 삽입으로 인해 발생할 수 있는 오류를 줄여 환자에게 최적의 치료를 시행할 수 있었다.

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Radiochromic film dosimetry for linac-based stereotactic radiosurgery

  • Han, Seung-Hee;Park, Suk-Won;Oh, Do-Hoon
    • 한국의학물리학회:학술대회논문집
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    • 한국의학물리학회 2002년도 Proceedings
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    • pp.302-304
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    • 2002
  • In linac-based stereotactic radiosurgery, assuring the quality of the planning and delivery of external photon beam requires accurate evaluation of beam parameters, usually including output factors, tissue-phantom ratio and off-axis ratios, and measurement of actual dose distributions from simulated treatment. We're going to test the use of calibrated radio chromic film (Gafchromic film; type MD-55, Nuclear associate) using a Lumiscan 75 digitizer to measure absolute dose and relative dose distributions for linac-based radiosurgery unit Relative dose distribution of a human-style spherical acryl phantom were measured using radiochromic film and calculated by treatment planning system. The absolute dose at the sphere center was measured by radiochromic film and micro chamber (Exradin A-14, 0.009cc). What we want to demonstrate in this work, the 'well selected' radiochromic films when external photon beam are used in linac-based stereotactic radiosurgery are very accurate detector for dosimetry.

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MC-50 의학용 싸이클로트론의 특성조사

  • 박주식
    • 대한방사선치료학회지
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    • 제2권1호
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    • pp.23-29
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    • 1987
  • The general features and measured results of the 143cm, variable-energy, three sector-focused MC-50 cyclotron installed at Korea Cancer Center Hospital are described. The MC-50 cyclotron is designed to produce beams of protons, deuterons, He-3 and alpha particles of maximum energies 50MeV, 25MeV, 66MeV and 50MeV respectively to be used for neutron therapy and radioisotope production. The azimuthal field variation is produced by three sets of spiral ridges having a maximum spiral angle of $55^{\circ}$. The RF system, a two-dee quarter-wave system is designed to provide a continuously variable frequency from 15.5 to 26.8 MHz. The first external beam was obtained in January 1986. Subsequent internal ana external beam studies with protons and alphas show a well-behaved beam through the whole beam transport system.

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3차원 입체조형치료시 Auto Contouring tool의 유용성 평가 (Evaluation of auto contouring accuracy in 3D planning system)

  • 최지민;주상규;박주영;박영환;김종식
    • 대한방사선치료학회지
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    • 제14권1호
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    • pp.35-39
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    • 2002
  • Introduction : It is essential to input patients external contour in 3D treatment plan. We would like to see changes in depth and dose when 3D RTP is operating auto contouring when windows value (Width/Level) differs in this process. Material & Methode : We have analyzed the results with 3D RTP after CT Scanning with round CT Phantom. We have compared and analyzed MU values according to depth changes to Isocenter changing external contour and inputting random Window value. We have watched change values according to dose optimization in 4 directions(LAO, LPO, RAO, RPO), We plan 100 case for exact analyzation. We have results changing window value random to each beam in 100 cans. Result : It showed change between minimum and maximum value in 4 beam is Depth 0.26mm, MU $1.2\%$ in LAO. It showed LPO-Depth 0.13mm, MU $0.9\%$, RAO-Depth 0.2mm MU $0.8\%$, RPO-Depth 0.27mm, MU $1.1\%$ Conclusion : Maximum change in depth 0.27 mm, MU error rate is $0.12\%$ according to Window change. As we can see in these results, it seems Window value change doesn't effect in treatment. However, it seems there needs to select appropriate Window value in precise treatment.

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원격전이의 증거가 없는 식도암의 방사선치료 성적 (Result of Radiotherapy in Non-metastatic Esophageal Cancer)

  • 채규영;장정순;이종석
    • Radiation Oncology Journal
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    • 제13권1호
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    • pp.27-31
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    • 1995
  • Purpose : This study was done to evaluate preliminarily the role of intraluminal brachytherapy in the radiation treatment of non-metastatic esophageal cancer, Materials and Methods: We analyzed follow-up result of 21 patients treated at the dept. of therapeutic radiology in Gyeongsang national university hospital between April, 1989 and August, 1992. All patients received neoadjuvant chemotherapy(5-FU, Cispl-atin). Fifteen Patients were treated with external beam alone, and in remaining 6 patients, the external beam radiotherapy followed by intraluminal brachytherapy was done. Results : Among 21 patients, 7 patients showed complete tumor regression after completion of radiotherapy. But 2 of these complete responder recurred at the site of primary disease, so ultimate local control rate was $23.8\%$(5/21). Local control rate according to radiation treatment modality was $6.7\%$(1/15) in patients treaed with external irradiation only, and $66.7\%$ in patients treated with combined external irradiation and intraluminal brachytherapy. The 2 year NED survival rate was $6.6.\%$ in the former and $66.7\%$ in the latter. Conclusion: Although there should be consideration about case selection for addition of intraluminal brachytherapy intraluminal brachytherapy may be considerded as one of the method to enhance the local control probability of esophageal cancer.

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Development of a Real-Time Internal and External Marker Based Gating System for Proton Therapy

  • Cho, Junsang;Cheon, Wonjoong;Ahn, Sanghee;Lee, Moonhee;Park, Hee Chul;Han, Youngyih
    • 한국의학물리학회지:의학물리
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    • 제28권3호
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    • pp.92-99
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    • 2017
  • In respiratory-induced proton therapy, the accuracy of tracking system and beam controlling is more important than photon therapy. Therefore, a high accuracy motion tracking system that can track internal marker and external surrogate is needed. In this research, our team has installed internal and external marker tracking system at our institution's proton therapy system, and tested the scanning with gating according to the position of marker. The results demonstrate that the developed in-house external/internal marker based gating system can be clinically used for proton therapy system for moving tumor treatment.

외부조사 방사선치료 기간 중 총담도 스텐트의 위치 변화가 컸던 사례 (A Bile Duct Cancer Patient Whose Stent Shifted Significantly Over the Course of External Beam Radiotherapy)

  • 윤형근
    • Radiation Oncology Journal
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    • 제29권2호
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    • pp.121-126
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    • 2011
  • 담도암 환자의 방사선치료 기간 중, 총담도에 삽입된 스텐트가 환자 복부의 우측부터 좌측까지 매우 넓은 범위로 움직인 경우를 발견하였다. 환자는 80세 노령의 여자로 흉추가 심한 척추 후만증을 보였고 흉추와 요추 몇 부위들에 압박골절이 있어서 키가 작았고 복부장기들이 아래로 내려와 있었다. 환자는 쇠약하고 야윈 상태였는데 방사선치료 기간 중 매주 컴퓨터단층촬영을 시행하여 비교한 결과 몸의 좌우방향으로 4 cm 이상의 스텐트의 위치 이동을 보였다. 따라서 흉추 후만증이 있으며서 몸이 매우 야윈 담도암 환자의 경우 방사선치료 범위 설정 시에 치료 기간 중 담도나 스텐트가 크게 움직일 가능성을 고려해야 할 것이다.

진행된 식도암의 방사선 단독치료 성적 (External Beam Radiotherapy Alone in Advanced Esophageal Cancer)

  • 안성자;정웅기;나병식;남택근
    • Radiation Oncology Journal
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    • 제18권1호
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    • pp.11-16
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    • 2000
  • 목적 : 진행된 식도암 환자에서 외부 방사선 단독치료를 받았던 환자의 치료성적에 대하여 후향적 분석을 시행하였다. 재료 및 방법 : 흉곽내에 위치한 편평상피세포암의 식도암으로 1990년 7월부터 1996년 12월까지 전남대학교병원 치료방사선과에서 외부 방사선 단독 치료를 받은 106명을 대상으로 후향적 분석을 시행하였다. 근치 목적의 방사선은 6 MV 혹은 10 MV X선으로 55 Gy에서 70.8 Gy 의 선량으로 통상적인 분할치료를 시행하였다. 추적이 가능한 환자는 100명(94$\%$)으로 추적기간은 1개월에서 92개월(중앙값: 6개월)이었다. 결과 :전체환자의 중앙연령은 62세였으며, 남녀 비율은 104:2였다. 가장 흔한 병변부위는 중앙 부위로 54$\%$를 차지하였다. 83$\%$의 환자가 근치목적의 방사선치료를 받았고 이들의 평균 방사선 선량은 58.6 Gy였으며(55$\~$70.8 Gy)평균 치료소요기간은 53일이었다. 전체환자의 중앙생존기간은 6개월이었고, 1, 2년 생존율은 각각 27, 12$\~$였다. 연하곤란으로 위루술을 시행한 7명을 제외하고 대부분의 환자에서 증상의 완화를 보였다. 치료 직후 완전 관해율은 32$\~$ (34/106)였고 이들 환자의 중앙생존기간(14개월)과 2년 생존율(30$\%$)은 다른 환자의 중앙생존기간(4개월)과 2년 생존율(30$\%$)에 비해 좋았다(p=0.000). 진단시 연하곤란의 정도에 따른 중앙생존기간과 2년 생존율을 비교해보면, 정상적인 음식물 섭취가 가능한 경우는 9개월과 16$\%$인 반면, 전혀 음식물을 삼킬 수 있었던 환자의 경우는 3개월과 0$\%$였다(p=0.004). 그러나 식도주변조직의 침범이나 주변 임파절 침범 유무에 따른 두 군간의 성적의 차이는 보이지 않았다. 다요인 분석에서는 방사선치료 직후 종양의 완해 여부가 가장 중요하였고 그외 원발 병소의 길이, 진단 당시 연하곤란의 정도 순으로 생존율에 통계적으로 유의한 영향을 주는 인자였다. 치료로 인한 부작용은 10명의 환자에서 관찰되었다(9$\%$). 결론 : 진행된 식도암 환자의 외부방사선 단독 치료는 좋지 않은 결과를 보여 주었다. 이에 진행된 병기의 식도암환자의 치료 선택에 있어서 반드시 근접치료나 항암화학요법의 병행을 고려해야 하겠다.

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방사선 치료용 고에너지 전자선의 조직 내 선량분포 특성에 관한 연구 (Study on Characteristics of Dose Distribution in Tissue of High Energy Electron Beam for Radiation Therapy)

  • 나수경
    • 대한방사선치료학회지
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    • 제14권1호
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    • pp.175-186
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    • 2002
  • The purpose of this study is directly measure and evaluate about absorbed dose change according to nominal energy and electron cone or medical accelerator on isodose curve, percentage depth dose, contaminated X-ray, inhomogeneous tissue, oblique surface and irradiation on intracavitary that electron beam with high energy distributed in tissue, and it settled standard data of hish energy electron beam treatment, and offer to exactly data for new dote distribution modeling study based on experimental resuls and theory. Electron beam with hish energy of $6{\sim}20$ MeV is used that generated from medical linear accelerator (Clinac 2100C/D, Varian) for the experiment, andwater phantom and Farmer chamber md Markus chamber und for absorbe d dose measurement of electron beam, and standard absorbed dose is calculated by standard measurements of International Atomic Energy Agency(IAEA) TRS 277. Dose analyzer (700i dose distribution analyzer, Wellhofer), film (X-OmatV, Kodak), external cone, intracavitary cone, cork, animal compact bone and air were used for don distribution measurement. As the results of absorbed dose ratio increased while irradiation field was increased, it appeared maximum at some irradiation field size and decreased though irradiation field size was more increased, and it decreased greatly while energy of electron beam was increased, and scattered dose on wall of electron cone was the cause. In percentage depth dose curve of electron beam, Effective depth dose(R80) for nominal energy of 6, 9, 12, 16 and 20 MeV are 1.85, 2.93, 4.07, 5.37 and 6.53 cm respectively, which seems to be one third of electron beam energy (MeV). Contaminated X-ray was generated from interaction between electron beam with high energy and material, and it was about $0.3{\sim}2.3\%$ of maximum dose and increased with increasing energy. Change of depth dose ratio of electron beam was compared with theory by Monte Carlo simulation, and calculation and measured value by Pencil beam model reciprocally, and percentage depth dose and measured value by Pencil beam were agreed almost, however, there were a little lack on build up area and error increased in pendulum and multi treatment since there was no contaminated X-ray part. Percentage depth dose calculated by Monte Carlo simulation appeared to be less from all part except maximum dose area from the curve. The change of percentage depth dose by inhomogeneous tissue, maximum range after penetration the 1 cm bone was moved 1 cm toward to surface then polystyrene phantom. In case of 1 cm and 2 cm cork, it was moved 0.5 cm and 1 cm toward to depth, respectively. In case of air, practical range was extended toward depth without energy loss. Irradiation on intracavitary is using straight and beveled type cones of 2.5, 3.0, 3.5 $cm{\phi}$, and maximum and effective $80\%$ dose depth increases while electron beam energy and size of electron cone increase. In case of contaminated X-ray, as the energy increase, straight type cones were more highly appeared then beveled type. The output factor of intracavitary small field electron cone was $15{\sim}86\%$ of standard external electron cone($15{\times}15cm^2$) and straight type was slightly higher then beveled type.

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Simulating the impact of iodine as a contrast substance to enhance radiation to the tumor in a brain x-rayphototherapy

  • M. Orabi
    • Nuclear Engineering and Technology
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    • 제55권5호
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    • pp.1671-1676
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    • 2023
  • The influence of adding iodine as a contrast substance to elevate radiation in a tumor is studied using simulation techniques of Monte-Carlo. The study is carried on a brain cancer by adopting an unsophisticated head phantom. The ionizing radiation source is an external beam of x-rays with energy range of a few tens of keV. The expected radiation dose increment due to adding the iodine is investigated by comparing the radiation in the tumor after and before adding the iodine and calculating the ratio between the two doses. Several concentrations of the contrast substance are used to quantify its impact. The change of the dose increment with the source energy is also examined. It is found that the radiation elevation in the tumor tends to saturate with increasing the iodine concentration, and for the studied domain of energies (30 keV-100 keV), the radiation dose enhancement factors (RDEF) for the different iodine concentrations (1%-9%) show peaked curves, with the peak occurring between 60 keV and 70 keV. For the highest concentration studied, 9%, the peak value is almost 7.