• Nuclear Engineering and Technology
• /
• 제38권4호
• /
• pp.327-342
• /
• 2006

Radiation therapy is an important part of cancer treatment in which cancer patients are treated using high-energy radiation such as x-rays, gamma rays, electrons, protons, and neutrons. Currently, about half of all cancer patients receive radiation treatment during their whole cancer care process. The goal of radiation therapy is to deliver the necessary radiation dose to cancer cells while minimizing dose to surrounding normal tissues. Success of radiation therapy highly relies on how accurately 1) identifies the target and 2) aim radiation beam to the target. Both tasks are strongly dependent of imaging technology and many imaging modalities have been applied for radiation therapy such as CT (Computed Tomography), MRI (Magnetic Resonant Image), and PET (Positron Emission Tomogaphy). Recently, many researchers have given significant amount of effort to develop and improve imaging techniques for radiation therapy to enhance the overall quality of patient care. For example, advances in medical imaging technology have initiated the development of the state of the art radiation therapy techniques such as intensity modulated radiation therapy (IMRT), gated radiation therapy, tomotherapy, and image guided radiation therapy (IGRT). Capability of determining the local tumor volume and location of the tumor has been significantly improved by applying single or multi-modality imaging fur static or dynamic target. The use of multi-modality imaging provides a more reliable tumor volume, eventually leading to a better definitive local control. Image registration technique is essential to fuse two different image modalities and has been In significant improvement. Imaging equipments and their common applications that are in active use and/or under development in radiation therapy are reviewed.

• Journal of Korean Neurosurgical Society
• /
• 제61권3호
• /
• pp.386-392
• /
• 2018

Radiation therapy is highly effective for the management of pediatric malignant central nervous system (CNS) tumors including embryonal tumors. With the increment of long-term survivors from malignant CNS tumors, the radiation-related toxicities have become a major concern and we need to improve the treatment strategies to reduce the late complications without compromising the treatment outcomes. One of such strategies is to reduce the radiation dose to craniospinal axis or radiation volume and to avoid or defer radiation therapy until after the age of three. Another strategy is using particle beam therapy such as proton beams instead of photon beams. Proton beams have distinct physiologic advantages over photon beams and greater precision in radiation delivery to the tumor while preserving the surrounding healthy tissues. In this review, I provide the treatment principles of pediatric CNS embryonal tumors and the strategic improvements of radiation therapy to reduce treatment-related late toxicities, and finally introduce the increasing availability of proton beam therapy for pediatric CNS embryonal tumors compared with photon beam therapy.

• Radiation Oncology Journal
• /
• 제37권4호
• /
• pp.302-308
• /
• 2019

The abscopal effect is a term that has been used to describe the phenomenon in which localized radiation therapy treatment of a tumor lesion triggers a spontaneous regression of metastatic lesion(s) at a non-irradiated distant site(s). Radiation therapy induced abscopal effects are believed to be mediated by activation and stimulation of the immune system. However, due to the brain's distinctive immune microenvironment, extracranial abscopal responses following cranial radiation therapy have rarely been reported. In this report, we describe the case of 42-year-old female patient with metastatic melanoma who experienced an abscopal response following her cranial radiation therapy for her brain metastasis. The patient initially presented with a stage III melanoma of the right upper skin of her back. Approximately 5 years after her diagnosis, the patient developed a large metastatic lesion in her upper right pectoral region of her chest wall and axilla. Since the patient's tumor was positive for BRAF and MEK, targeted therapy with dabrafenib and trametinib was initiated. However, the patient experienced central nervous system (CNS) symptoms of headache and disequilibrium and developed brain metastases prior to the start of targeted therapy. The patient received radiation therapy to a dose of 30 Gy delivered in 15 fractions to her brain lesions while the patient was on dabrafenib and trametinib therapy. The patient's CNS metastases improved significantly within weeks of her therapy. The patient's non-irradiated large extracranial chest mass and axilla mass also shrank substantially demonstrating the abscopal effect during her CNS radiation therapy. Following radiation therapy of her residual chest lesions, the patient was disease free clinically and her CNS lesions had regressed. However, when the radiation therapy ended and the patient continued her targeted therapy alone, recurrence outside of her previously treated fields was noted. The disease recurrence could be due to the possibility of developing BRAF resistance clones to the BRAF targeted therapy. The patient died eventually due to wide spread systemic disease recurrence despite targeted therapy.

• 한국생물물리학회:학술대회논문집
• /
• 한국생물물리학회 2002년도 제9회 학술 발표회 프로그램과 논문초록
• /
• pp.25-26
• /
• 2002

The goal of radiation therapy is to maximize the tumor dose and to minimize the dose of normal tissue. In order to achieve this goal, the new radiation therapy techniques such as three dimensional conformal therapy or intensity modulated radiation therapy has been developed and tried to clinical application. The relationship between radiation dose and normal tissue response is an interesting subject in the radiation therapy field.(omitted)

• 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.

• 대한방사선치료학회지
• /
• 제28권1호
• /
• pp.1-5
• /
• 2016

본원에서 수술 후 방사선치료를 수행한 하지 연부조직육종 환자에 대해 용적세기조절회전치료(VMAT), 세기조절방사선치료(IMRT), 3차원입체조영방사선치료(3D-CRT)의 세 가지 치료계획을 수립하여 치료계획용적(PTV)과 대퇴골에 전달되는 방사선량을 각각 비교하였다. 세 치료계획방법 모두 치료계획용적에 전달되는 방사선량은 큰 차이를 보이지 않았으나 용적세기조절회전치료와 세기조절방사선치료의 경우 3차원입체조영방사선치료보다 대퇴골에 전달되는 방사선량을 줄일 수 있었다. 또한 용적세기조절회전치료의 경우 세기조절방사선치료 보다 치료에 필요한 monitor unit이 적어 치료시간 감소의 효과가 나타났다. 따라서 하지 연부조직육종 방사선치료 시 용적세기조절회전치료의 사용은 효과적인 방사선치료를 수행할 수 있을 것이라 사료된다.

• Radiation Oncology Journal
• /
• 제12권3호
• /
• pp.323-329
• /
• 1994

Purpose: In supraglottic cancer, radiation therapy is used to preserve the laryngeal function but combined surgery and radiation therapy is required in advanced stage. The authors Present the results of radiation therapy alone and combined surgery Plus Postoperative radiation therapy for supraglottic cancer. Methods and Materials: A retrospective analysis was done for 43 patients with squamous cell carcinoma of the supraglottic larynx who were treated from Feburary 1982 to December 1991, in the Department of Radiation Oncology, Korea University Hospital. Patient distribution according to the AJCC staging system was as follows: I, 3($7.0\%$); II, 7($16.3\%$); III, 17($39.5\%$); IV, 16($37.2\%$). Patients' age ranged from 30 to 72 years(median 62). Follow up durations were from 21 to 137 months(median 27). Seventeen patients($39.5\%$) were treated by radiation therapy alone with radiation doses of 6840-7380 cGy and 26 patients($60.5\%$) were treated with surgery plus postoperative irradiation with doses of 5820-6660 cGy. Results: Overall five-year survival rate for all stage was $51.8\%$, with $100\%$ for Stage I and II, $47.3\%$ for Stage III, and $29.2\%$ for Stage III. The difference of the survival rate by stage was statistically significant(p=0.0152). Five-year survival rates were $100\%$ for locally confined tumor in the supraglottic larynx, $37.5\%$ for transglottic extension, $26.7\%$ for hypopharynx extension, and only two of 5 patients with both transglottic and hypopharynx extension were alive(p=0.0033). Five-year survival rates by neck node status were as follows: $55.0\%$ for NO, $64.3\%$ for N1, $50.0\%$ for N2, and all 2 of N3 were died of disease. Overall survival rate for radiation therapy alone group was $42.8\%$, and it was $56.7\%$ for surgery plus postoperative radiation therapy group with no statistically significant difference(p=0.5215). In Stage I and II, all Patients survived. In Stage III and IV, 5-year survival rate for radiation therapy alone group was $28.5\%$ and $43.4\%$ for surgery plus postoperative irradiation group(p=0.5103). Local control rate was $58.8\%$(10/17) for radiation therapy alone group and $73.1\%$ (19/26) for surgery plus postoperative irradiation group. Three patients from surgery plus postoperative radiation therapy group developed distant metastasis in lungs. Conclusion: Treatment results of radiation therapy alone was excellent in early stage supraglottic cancer. In advanced stage, even the difference was statistically not significant, the result of postoperative radiation therapy group was superior compared with radiation therapy alone group. Since 1992, concomitant chemoradiotherapy with hyperfractionated radiotherapy is being used to improve the result of the treatment and preserve the laryngeal function in advanced stage supraglottic cancer.

• 한국응용약물학회:학술대회논문집
• /
• 한국응용약물학회 1999년도 춘계학술대회
• /
• pp.53-61
• /
• 1999

Radiation therapy has been used for the cancer treatment and radiation synovectomy$\^$1-3)/. There are two kinds of radiation therapy; the external radiation therapy and the internal radiation therapy. Hitherto, the external radiation therapy has been widely used, but for the lack of its selectivity it requires strong radiation dose and causes the irritation and damage of the normal tissue or organ. Therefore many researchers give their interests to the internal radiation therapy in which the radioactive materials are injected directly into the target organ or tissue. Many ${\beta}$-emitting radionuclides have been studied for the application of the internal radiation theraily. Among them, Holmium-166 has the many beneficial physical characteristics for the internal radiation therapy such as appropriate half life (26.8hr), high ${\beta}$ energy (max. 1.85 MeV(51%), 1.77 MeV (48%), mean 0.67MeV), and low ${\gamma}$ energy (0.081MeV) easily detected by ${\gamma}$-camera. In the internal radiation therapy, the administered radioactive materials should be retained in the target long enough to increase the therapeutic effects and avoid the damage in the normal tissue or organ. For this purpose, radionuclides are used as complex form with carriers. Carriers should have a high affinity with radionuclides in vivo and in vitro, so the complex can be evenly distributed in the lesion but can not be leaked out from the lesion.

• Radiation Oncology Journal
• /
• 제36권1호
• /
• pp.1-10
• /
• 2018

Intensity-modulated radiation therapy (IMRT) has been considered the most successful development in radiation oncology since the introduction of computed tomography into treatment planning that enabled three-dimensional conformal radiotherapy in 1980s. More than three decades have passed since the concept of inverse planning was first introduced in 1982, and IMRT has become the most important and common modality in radiation therapy. This review will present developments in inverse IMRT treatment planning and IMRT delivery using multileaf collimators, along with the associated key concepts. Other relevant issues and future perspectives are also presented.

• Radiation Oncology Journal
• /
• 제2권2호
• /
• pp.253-260
• /
• 1984

Between January 1971 and December 1580 fifteen patients diagnosed of adenocarcinoma of the endometrium, stage II seen and treated at the University of Michigan Hospitals. are reviewed. Ten patients were treated with radiation therapy alone. five received hysterectomy after radiation. The five year survival of the patients receiving radiation and surgery was $100\%$ although one of them died after 62 month aster treatment. Of those receiving radiotherapy alone two died at i and 24months after therapy. All of the patients died of distant metastasis. Radiation cystitis was observed among surgically treated patients. while proctitis was observed in 3 cases receiving radiation alone. Though the number of cases reported is small due to rarity of the disease. it appears that radiation alone could provide reasonable tumor control. Also it appears that preoperative irradiation might lead to a longer survival. One patient who survived 62 months had para-aortic node involvement.