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Multi‐layer energy filter for realizing conformal irradiation in charged particle therapy
Author(s) -
Sakae Takeji,
Nohtomi Akihiro,
Maruhashi Akira,
Sato Masaru,
Terunuma Toshiyuki,
Kohno Ryosuke,
Akine Yasuyuki,
Hayakawa Yoshinori,
Koike Yasunori
Publication year - 2000
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.598840
Subject(s) - sobp , optics , bragg peak , monte carlo method , filter (signal processing) , conformal map , materials science , irradiation , proton therapy , physics , geometry , beam (structure) , computer science , mathematics , statistics , nuclear physics , computer vision
A new type of filter for charged particle radiotherapy is developed to reduce unwanted dose transfer to the normal tissues around a tumor. The new filter can make a static irradiation field where the width of the spread‐out Bragg peak (SOBP) is two‐dimensionally adjusted. That makes the field conformal to the tumor three‐dimensionally. The filter is made of many layers produced by using stereolithography. The layer has a miniaturized structure that has geometrical similarity to the conventional ridge filter. Shapes of cone and pyramid are also usable for the unit‐cell constructing the layer. The spread of the field in the depth direction is decided by the thickness of the filter, or by the number of layers. The experimental result of the irradiation using the ridge‐type construction shows a good agreement with an estimate by the Monte Carlo calculation. By combining this technique with intensity modulation that has lateral position dependence, the conformal irradiation can be achieved by a simple procedure.