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1 Past, Present, and Future of Radiation Oncology Masahiro Hiraoka, M.D. Department of Therapeutic Radiology and Oncology, Kyoto University Graduate School of Medicine NICHIDOKU-IHO Vol. 50 No (2005) Summary The history of radiation oncology dates back to the discovery of X-rays by Roentgen in In the past, the energy of photons was not sufficient to deliver irradiation to deep-seated tumors. With the development of high-energy radiotherapy equipment such as telecobalt machines and linear accelerators, the outcome of radiotherapy treatment has improved greatly. The current topics in radiation oncology are chemoradiotherapy and threedimensional conformal radiotherapy (3D-CRT). The combination of radiation therapy and chemotherapy has been investigated clinically for various locally advanced cancers. Concurrent chemoradiotherapy has demonstrated clinical benefits, and is recognized as a standard treatment for cancers of the head and neck, lung, esophagus, pancreas, and uterus. The development of 3D-CRT has enabled us to irradiate tumors as locally as possible, leading to dose escalation in the tumor while not increasing the dose to radiosensitive normal tissues. The most advanced techniques for 3D-CRT are stereotactic irradiation (STI) and intensity-modulated radiation therapy (IMRT). STI for intracranial tumors has been widely available since 1990, and its usefulness is well recognized. Recently, the technique has been expanded to cover extracranial tumors, including tumors in the lung and liver. Clinical trials for lung tumors are being extensively investigated in Japan. The clinical outcome for stage I non-small-cell lung cancer has been excellent, and STI has been approved for coverage under Japan s national health insurance. Recent rapid progress in computer technology has brought us clinically applicable computer optimization algorithms. At the same time, several innovative computer-controlled X-ray delivery techniques have been developed to realize non-homogeneous dose intensity calculated by computer optimizations. Here, the intensity-modulated radiotherapy technique has two main features, computer optimization and inhomogeneous beam delivery. These features have enabled us to realize distributions not achievable with the conventional 3D-CRT technique. IMRT has been intensively used in the US and Europe to increase the dose to tumor or to decrease the dose to critical normal tissues. The most common tumor treated by IMRT is prostate cancer. Many trials have demonstrated improvement in survival outcomes while maintaining a low incidence of rectal injuries. Tumors in the head and neck region also are often treated by IMRT. A good indication is nasopharyngeal cancer. The strategy of IMRT for this tumor is to increase the dose to the primary tumor and decrease the dose to the parotid glands using the technique of dose painting. The clinical reality is improved survival and fewer late complications associated with salivary dysfunction. The future of radiation oncology is tailor-made radiation therapy, which will require both physical and biological approaches for its realization. Physical approaches include bio-imaging-guided IMRT and image-guided radiation therapy (IGRT). Biological approaches are the development of bio-imaging that is useful for radiotherapy and molecular targeting drugs that will increase radiosensitivity or destroy radioresistant areas in the tumor.

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Title 泌尿器科領域に於ける17-Ketosteroidの研究 17-Ketosteroidの臨床的研究第 III 篇 : 尿 Author(s) 卜部, 敏入 Citation 泌尿器科紀要 (1958), 4(1): 3-31 Issue Date URL

Title 泌尿器科領域に於ける17-Ketosteroidの研究 17-Ketosteroidの臨床的研究第 III 篇 : 尿 Author(s) 卜部, 敏入 Citation 泌尿器科紀要 (1958), 4(1): 3-31 Issue Date 1958-01 URL http://hdl.handle.net/2433/111559 Right Type Departmental Bulletin