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Monte Carlo-based correction factors for ion chamber dosimetry in heterogeneous phantoms for megavoltage photon beams
http://hdl.handle.net/2298/33043
http://hdl.handle.net/2298/3304379821fce-ead4-44ee-a14b-4ae7f6aa5979
| 名前 / ファイル | ライセンス | アクション |
|---|---|---|
Phys Med Biol_57_22_7615-7627.pdf (249.4 kB)
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| Item type | 学術雑誌論文 / Journal Article(1) | |||||
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| 公開日 | 2015-09-16 | |||||
| タイトル | ||||||
| タイトル | Monte Carlo-based correction factors for ion chamber dosimetry in heterogeneous phantoms for megavoltage photon beams | |||||
| 言語 | ||||||
| 言語 | eng | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_6501 | |||||
| 資源タイプ | journal article | |||||
| 著者 |
荒木, 不次男
× 荒木, 不次男 |
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| 別言語の著者 |
荒木, 不次男
× 荒木, 不次男 |
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| 内容記述 | ||||||
| 内容記述タイプ | Other | |||||
| 内容記述 | The purpose of this study was to investigate the perturbation correction factors and inhomogeneity correction factors (ICFs) for a thin-walled cylindrical ion chamber in a heterogeneous phantom including solid water, lung and bone plastic materials. The perturbation factors due to the replacement of the air cavity, non-water equivalence of the wall and the stem, non-air equivalence of the central electrode and the overall perturbation factor, P_Q, for a cylindrical chamber, in the heterogeneous phantom were calculated with the EGSnrc/Cavity Monte Carlo code for 6 and 15 MV photon beams. The PTW31010 (0.125 cm^3) chamber was modeled with Monte Carlo simulations, and was used for measurements and calculations of percentage depth ionization (PDI) or percentage depth dose (PDD). ICFs were calculated from the ratio of the product of the stopping power ratios (SPRs) and P_Q of lung or bone to solid water. Finally, the measured PDIs were converted to PDDs by using ICFs and were compared with those calculated by the Monte Carlo method. The perturbation effect for the ion chamber in lung material is insignificant at 5×5 and 10×10cm^2 fields, but the effect needs to be considered under conditions of lateral electron disequilibrium with a 3×3cm^2 field. ICFs in lung varied up to 2% and 4% depending on the field size for 6 and 15 MV, respectively. For bone material, the perturbation effects due to the chamber wall and the stem were more significant at up to 3.5% and 1.6% for 6 MV, respectively. ICFs for bone material were approximately 0.945 and 0.940 for 6 and 15 MV, respectively. The converted PDDs by using ICFs were in good agreement with Monte Carlo calculated PDDs. The chamber perturbation correction and SPRs should strictly be considered for ion chamber dosimetry in heterogeneous media. This is more important for small field dosimetry in lung and bone materials. | |||||
| 書誌情報 |
Physics in Medicine and Biology 巻 57, 号 22, p. 7615-7627, 発行年 2012-10-26 |
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| ISSN | ||||||
| 収録物識別子 | 00319155 | |||||
| 書誌レコードID | ||||||
| 収録物識別子タイプ | NCID | |||||
| 収録物識別子 | AA10558592 | |||||
| PubMed番号 | ||||||
| 関連タイプ | isVersionOf | |||||
| 識別子タイプ | PMID | |||||
| 関連識別子 | 23103477 | |||||
| DOI | ||||||
| 関連タイプ | isVersionOf | |||||
| 関連識別子 | 10.1088/0031-9155/57/22/7615. | |||||
| 権利 | ||||||
| 権利情報 | © 2012 Institute of Physics and Engineering in Medicine | |||||
| フォーマット | ||||||
| 内容記述タイプ | Other | |||||
| 内容記述 | application/pdf | |||||
| 形態 | ||||||
| 値 | 249420 bytes | |||||
| 著者版フラグ | ||||||
| 出版タイプ | AM | |||||
| 出版タイプResource | http://purl.org/coar/version/c_ab4af688f83e57aa | |||||
| 出版者 | ||||||
| 出版者 | IOP Publishing | |||||
| 資源タイプ | ||||||
| 内容記述タイプ | Other | |||||
| 内容記述 | 論文(Article) | |||||
| 資源タイプ・ローカル | ||||||
| 値 | 雑誌掲載論文 | |||||
| 資源タイプ・NII | ||||||
| 値 | Journal Article | |||||
| 資源タイプ・DCMI | ||||||
| 値 | text | |||||
| 資源タイプ・ローカル表示コード | ||||||
| 値 | 01 | |||||
| URL | ||||||
| 内容記述タイプ | Other | |||||
| 内容記述 | http://iopscience.iop.org/article/10.1088/0031-9155/57/22/7615/meta;jsessionid=9DDC0BEC8AC5C3D54172F395A5F1E958.c1 | |||||
| コメント | ||||||
| 値 | 【著者所属】熊本大学大学院生命科学研究部 医用画像学 | |||||
