• Title, Summary, Keyword: Radiation therapy

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IMAGING IN RADIATION THERAPY

  • Kim Si-Yong;Suh Tae-Suk
    • Nuclear Engineering and Technology
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    • v.38 no.4
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    • pp.327-342
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    • 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.

Radiation Therapy against Pediatric Malignant Central Nervous System Tumors : Embryonal Tumors and Proton Beam Therapy

  • Lim, Do Hoon
    • Journal of Korean Neurosurgical Society
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    • v.61 no.3
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    • pp.386-392
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    • 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.

Extracranial systemic antitumor response through the abscopal effect induced by brain radiation in a patient with metastatic melanoma

  • D'Andrea, Mark A.;Reddy, G.K.
    • Radiation Oncology Journal
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    • v.37 no.4
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    • pp.302-308
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    • 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.

Deep inspiration breath-hold (DIBH) 적용한 림프절이 포함된 왼편 유방암의 방사선 치료계획에 따른 주변 장기 선량 평가

  • Jeong, Da-Lee;Gang, Hyo-Seok;Choe, Byeong-Jun;Park, Sang-Jun;Lee, Geon-Ho;Lee, Du-Sang;An, Min-U;Jeon, Myeong-Su
    • The Journal of Korean Society for Radiation Therapy
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    • v.29 no.1
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    • pp.27-35
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    • 2017
  • Purpose: On the left side, breast cancer patients have more side effects than those on the right side because of unnecessary doses in normal organs such as heart and lung. DIBH is performed to reduce this. To evaluate the dose of peripheral organs in the left breast cancer including supraclavicular lymph nodes and internal mammary lymph nodes according to the treatment planning method of Conventional Radiation Therapy, Intensity Modulated Radiation Therapy and Volumetric Modulated Arc Therapy. Materials and Methods: We performed CT-simulation using free breathing and deep inspiration breath-hold technique for 8 patients including left supraclavicular lymph nodes and internal mammary lymph nodes. Based on the acquired CT images, the contour of the body is drawn and the convention is performed so that $95%{\leftarrow}PTV$, $Dmax{\leftarrow}110%$. Conventional Radiation Therapy used a one portal technique on the supraclavicular lymph node and used a field in field technique tangential beam on the breast. Intensity Modulated Radiation Therapy was composed of 7 static fields. Volumetric Modulated Arc Therapy was planned using 2 ARC with a turning radius of $290^{\circ}$ to $179^{\circ}$. The peripheral normal organs dose was analyzed by referring to the dose volume of Eclipse. Results: By applying the deep inspiration breath-hold technique, the mean interval between the heart and chest wall increased $1.6{\pm}0.6cm$. The mean dose of lung was $19.2{\pm}1.0Gy$, which was the smallest value in Intensity Modulated Radiation Therapy. The V30 (%) of the heart was $2.0{\pm}1.9$, which was the smallest value in Intensity Modulated Radiation Therapy. In the left anterior descending coronary artery, the dose was $25.4{\pm}5.4Gy$, which was the smallest in Intensity Modulated Radiation Therapy. The maximum dose value of the Right breast was $29.7{\pm}4.3Gy$ at Intensity Modulated Radiation Therapy. Conclusion: When comparing the values of surrounding normal organs, Intensity Modulated Radiation Therapy and Volumetric Modulated Arc Therapy were applicable values for treatment. Among them, Intensity Modulated Radiation Therapy is considered to be a suitable treatment planning method.

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Preliminary Study of Neuronal Response to Dose Distribution of Radiation with MR Spectroscopy

  • Ahn, Seung-Do;Yi, Byoung-Young;Lee, Jung-Hee
    • Proceedings of the Korean Biophysical Society Conference
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    • pp.25-26
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    • 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)

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Treatment Results for Supraglottic Cancer (성문상부암의 치료결과)

  • Lee, Kyu-Chan;Kim, Chul-Yong;Choi, Myung-Sun
    • Radiation Oncology Journal
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    • v.12 no.3
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    • pp.323-329
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    • 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.

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Development of Radiopharmaceutical DW-166HC for Anticancer drug

  • Man, Ryu-Jei
    • Proceedings of the Korean Society of Applied Pharmacology
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    • pp.53-61
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    • 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.

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Intensity-modulated radiation therapy: a review with a physics perspective

  • Cho, Byungchul
    • Radiation Oncology Journal
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    • v.36 no.1
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    • pp.1-10
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    • 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.

Why Do Patients Drop Out During Radiation Therapy? - Analyses of Incompletely Treated Patients - (불완전 방사선치료 환자의 분석)

  • Huh Seung Jae;Wu Hong Gyun;Ahn Yong Chan;Kim Dae Yong;Shin Kyung Hwan;Lee Kyu Chan;Chong Won A;Kim Hyun Joo
    • Radiation Oncology Journal
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    • v.16 no.3
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    • pp.347-350
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    • 1998
  • Purpose : This study is to see how much proportion of the patients receiving radiation therapy drop out during radiation therapy and to analyze the reason for the incomplete treatment. Materials and Methods : The base population of this study was 1,100 patients with registration numbers 901 through 2,000 at Department of Radiation Oncology, Samsung Medical Center, Seoul, Korea. Authors investigated the incidence of incomplete radiation therapy, which was defined as less than 95$\%$ of initially planned radiation dose, and the reasons for incomplete radiation therapy. Results : One hundred and twenty eight patients (12$\%$) did not complete the planned radiation therapy. The performance status of the incompletely treated patients was generally Poorer than that of the base population, and the aim of radiation therapy was more commonly palliative. The most common reason for not completing the planned treatment was the patients' refusal of further radiation therapy because of the distrust of radiation therapy and/or the poor economic status. Conclusion : Careful case selection for radiation therapy with consideration of the socioeconomic status of the patients in addition to the clinical indication would be necessary for the reduction of incomplete treatment, especially in the palliative setting.

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The Availability of Diagnostic and Treatment Planning Computer in 700 Cancer Patients and Magnification Devices for CT (암환자 700예의 진단 및 치료 CT 이용율과 CT 확대장치)

  • Lee, Gui-Won;Park, Joo-Sun;Han, Yong-Moon;Yoon, Sei-Chul;Shinn, Kyung-Sub
    • The Journal of Korean Society for Radiation Therapy
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    • v.2 no.1
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    • pp.81-85
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    • 1987
  • It has been evident since 1972 that computed tomography(CT) can play an important role in treatment and managment of the cancer patients as four steps; diagnosis, satging Treatment and follow-up. In this paper, we intended to investigate the availability of CT scan and treatment planning computer in 700 cancer patients who have undergone radiation therapy at the division of radiation therapy, Kangnam St. Mary's Hospital, Catholic Medical College between Mar. 1983 and Dec. 1985. The result were as follow; 1. Of 700 irradiated cancer patients, 342 patients ($48.9\%$) were performed CT scan prior to radiation therapy. 2. The distribution of lesions in 342 patients having CT scans was like this; CNS (83 of 104 patients, $79.8\%$), abdomen (44 of 76 patients, $57.9\%$), pelvis (100 of 188 patients, $53.2\%$) etc. in order. 3. The treatment planning computer were used in 280 cancer patients ($40\%$). 4. Of the 280 cancer patients using treatment planning computer, 167 patients ($59.6\%$) applied diagnostic CT scan and remaining 113 patients ($40.4\%$) were made body contour to be used for radiation therapy planning by the treatment planning computer. Authors also made some magnification devices used for small multiformat CT images to magnify into life size, consisting of overhead projector (3M) I.V. stand and mirror. These enabled us to make less errors in tracing the small-sized CT images during input of the anatomical data into the treatment planning computer.

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