AbstractID: 6752 Title: Evaluation of Kodak EC film for verification of IMRT dose distributions
There has been great interest in clinical implementation of intensity modulated radiation therapy (IMRT).
A key element for a successful implementation is to establish an effective quality assurance program, including dose verifications for individual patients. Two-dimensional (2D) measurement with films is an important part of overall dose verification. Kodak XV film is commonly used. One of the drawbacks of
XV film is its limited dose range for IMRT, resulting in an optical density (OD) too large, for a typical dose fraction size, to be accurately digitized by a typical commercial film digitizer. In this study, a new type of verification film, Kodak EC film, is evaluated for IMRT dose verification. Sensitometric curves are determined for both 6 MV and 23 MV photon beams from a linear accelerator. It is found that OD for typical dose fraction sizes is suitable for a typical film scanner. It is demonstrated that with EC film actual clinical dose levels can be used and common film digitizer are adequate. PDDs for both 6 and 23 MV xrays are also measured with EC and XV films and are compared with ion chamber data. Film data are within
±
2% of ion chamber results. Examples of measured IMRT isodose dose distributions compared with calculated isodoses will be presented. We have used EC films for commissioning the IMRT treatment planning system and all IMRT patients treated in our clinic. In conclusion, Kodak EC film is better than
XV film for 2D IMRT dose verifications.