| Автор | Heikki Tölli |
| Автор | Alex F Bielajew |
| Автор | Olof Mattsson |
| Автор | Göran Sernbo |
| Автор | Karl-Axel Johansson |
| Дата выпуска | 1997-07-01 |
| dc.description | In ionization chamber dosimetry close to brachytherapy sources, the non-uniform photon fluence in the vicinity of the air cavity of the ionization chamber must be corrected for. In this paper, experimentally determined relative non-uniformity correction factors are determined for a PTW23331 chamber and a number of Farmer-type chambers. It is concluded that the `anisotropic' theory of Bielajew agrees better with the experimental results than the `isotropic' theory of Kondo and Randolph. The experiments show that neither the material choice nor the radius of the central electrode have any significant effect on the non-uniformity correction factors. Experiments on the wall-material dependence in the non-uniformity correction factor, which is predicted by the anisotropic theory, were inconclusive. Parameters for the Farmer-type chambers for calculation of theoretical non-uniformity correction factors are given. Data to derive anisotropic fluence non-uniformity correction factors are given in tabular form. An error in the Kondo and Randolph equations is reported and the corrected equations presented. |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | Fluence non-uniformity effects in air kerma determination around brachytherapy sources |
| Тип | paper |
| DOI | 10.1088/0031-9155/42/7/006 |
| Electronic ISSN | 1361-6560 |
| Print ISSN | 0031-9155 |
| Журнал | Physics in Medicine and Biology |
| Том | 42 |
| Первая страница | 1301 |
| Последняя страница | 1318 |
| Выпуск | 7 |
