全食道照射の多重照射法による線量分布の改善

元データ 2002-06-20 社団法人日本放射線技術学会

概要

The wide radiation field for mediastinal dose distribution should be inhomogeneous with the usual simple opposed beam irradiation. The purpose of this study was to improve the dose distribution of the mediastinum using a conventional planning system with a dose-volume histogram(DVH)and the field-in-field technique. Three-dimensional (3D)dose distribution is obtained in bilateral opposed-field irradiation. An overdose area obtained from the 3D dose distribution is defined and reprojected into the irradiation field. A new reduced field is created by removing the reprojected overdose area. A 3D dose distribution is again obtained and compared with the results from first one. Procedures were repeated until each of the target volumes was within ±5 % of the prescribed dose and the irradiation volume within 107% or less of the prescribed dose. From the DVH analysis, our field-within-a-field technique resulted in a more uniform dose distribution within the conventional planning. The field-within-a-field technique involves many parameters, and an inverse planning algorithm is suitable for computation. However, with our method, the forward planning system is adequate for planning, at least in a relatively straightforward planning system such as bilateral opposed fields therapy.

著者

中澤 靖夫 昭和大学統括放射線技術部
岡部 圭吾 昭和大学病院放射線治療部
中澤 靖夫 昭和大学病院治験事務局運営委員会
倭 秀忠 昭和大学病院放射線部
岩井 譜憲 昭和大学病院中央放射線部
岡部 圭吾 昭和大学病院放射線部
加藤 光好 昭和大学診療放射線専門学校診療放射線学科
村上 順司 昭和大学病院放射線部
岩井 譜憲 昭和大藤が丘病院中央放射線部
中沢 靖夫 昭和大学病院放射線部
岩井 譜憲 昭和大学病院放射線部
中澤 靖夫 昭和大学病院

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