Journal of Okayama Medical Association
Published by Okayama Medical Association

Full-text articles are available 3 years after publication.

電子線moving strip法の試み

松島 紀志夫 岡山大学医学部附属病院中央放射線部
若狭 弘之 岡山大学医学部附属病院中央放射線部
小栗 宣博 岡山大学医学部附属病院中央放射線部
北山 卓一 岡山大学医学部附属病院中央放射線部
中桐 義忠 岡山大学医学部附属病院中央放射線部
三上 泰隆 岡山大学医学部附属病院中央放射線部
橋本 啓二 岡山大学医学部放射線医学教室
平木 祥夫 岡山大学医学部放射線医学教室
青野 要 岡山大学医学部放射線医学教室
96_1175.pdf 3.14 MB
The fieldsize in electron beam therapy is determined by the cone size. In cases of skin metastasis of a malignant tumor and so on, which need a large field size and whose area is much larger than the size of the cone, a large field size is usually produced by dividing the portals. However, the dose distribution at the border of the field becomes unequal, and hot and cold dose areas are produced according to the distance between portals. We tried the strip field technique in a large field along the long axis of the body in order to flatten the dose of the border employing the moving strip used for whole abdominal irradiation in ovarian cancer. We set the film in Mix-DP and used the strip field technique with 2.5cm steps. We discussed the relationship between the interval (distance between portals) and the flattening of the dose within the field. Skin movement due to breathing and influences on the flattening of the dose were considered. The proper flatness was obtained at depths of 0,1,2, and 3cm by setting the interval at 0.5cm. When skin movement was produced by breathing in ±1.5mm, the proper flaness was obtained also at a 0.5-cm interval. It seems that smoothing is increased by breathing. An "electron beam moving strip" with a 2.5-cm step and 0.5-cm interval was clinically effective in the treatment of patients with skin metastasis of colon cancer.
moving strip 法