In radiotherapy the dose delivery techniques are evolved rapidly. Intensity-modulated radiotherapy (IMRT) has non-uniform complex distribution and varying two-dimensional (2D) dose distribution. Therefore it is necessary to obtain 2D data. The radiographic film is more commonly used in this situation. The radiographic film features high resolution, and obtaining 2D data easily. In radiographic film dosimetry, the film is a few deflected from the beam axis at each facility. However, the adequate length of shift and the affect of shift do not clarify. Moreover, this study verifies the affect that the radiographic film deflected from the beam axis and that difference of measuring method by experimental measurement and Monte Carlo code EGS4. Experimental measurement and simulation performed two different arrangements. First method was a film protruded the upper edge of the phantom. Second method was the upper edge of a film matched that of the phantom. In each method, films were exposed in two patterns; one was the film was set under the beam axis and the other was the film was set 2 cm off from the beam axis. Density distributions obtained by the films were converted to percentage depth dose (PDD) curves. PDD curves obtained in the first method were not in good agreement with that of the ion chamber but PDD curves in the second was in good agreement in experimental measurement. However, PDD curves measured by the films accorded with PDD curve measured by ion chamber. Moreover, first method was more available than second method.
|Number of pages||4|
|Publication status||Published - 2006|
|Event||13th EGS Users' Meeting in Japan 2006 - Tsukuba, Japan|
Duration: 2006 Aug 8 → 2006 Aug 10
|Other||13th EGS Users' Meeting in Japan 2006|
|Period||06/8/8 → 06/8/10|
ASJC Scopus subject areas