Comparison of PDD curves obtained by therapeutic films and calculated by EGS5

R. Kawanami, C. Nejigaki, T. Shimozato, K. Yasui, K. Habara, K. Okudaira, Y. Aoyama, H. Shibata, T. Oshima, Y. Obata

Research output: Contribution to conferencePaperpeer-review

Abstract

Recently, dose delivery techniques are evolved rapidly in radiotherapy. Intensity-modulated radiotherapy (IMRT) enables a non-uniform complex dose distribution. Therefore, it is necessary to obtain data of two dimensional (2D) dose distribution. Radiographic films are more commonly used in this situation. The radiographic film features high resolution, and obtains 2D data easily. However, the standard method of the radiographic film dosimetry has not been established in radiotherapy. In this study, the radiographic film EDR2 (Kodak) and Gafchromic Film RT-QA (ISP. INC) were used and compared by measurements and Monte Carlo simulations. Both films were digitalized using a scanner (EPSON Offirio ES 100000G) and analyzed by the DD-system (R-TECH. INC). Density-dose conversion curves were plotted and percentage depth dose (PDD) curves were calculated by the DD-system. The simulation geometry was the same as the film measurement arrangement. In comparison of PDD curves for EDR2, the calculated curve was larger than the curve obtained by an ion chamber and the curve measured by the film dosimetry and PDD curves for RT-QA was smaller than the curve by the ion chamber. Thus, the calculated curve was overestimated and the curve by the film dosimetry was underestimated. On the other hand, calculated PDD for RT-QA was smaller than the PDD by the ion chamber and the curve measured by RT-QA agreed with the PDD by the ion chamber.

Original languageEnglish
Pages76-80
Number of pages5
Publication statusPublished - 2008
Event15th EGS Users' Meeting in Japan 2008 - Tsukuba, Japan
Duration: 06-08-200808-08-2008

Conference

Conference15th EGS Users' Meeting in Japan 2008
CountryJapan
CityTsukuba
Period06-08-0808-08-08

All Science Journal Classification (ASJC) codes

  • Software

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