Evaluation of Dose Differences Between Field in Field and Hybrid-IMRT Techniques For Breast Cancer Treatment

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Adjuvant radiation therapy (RT) after breast conserving surgery (BCS) has become a standard treatment modality for patients with early breast cancer. RT techniques for breast cancer have been continuously improved, from the earliest tangential field with wedge filter to field-in-field (FIF) technique, and then mixed Hybrid-intensity modulated radiation therapy (Hybrid-IMRT). The main purpose of the evolution of treatment is to decrease treatment-related side effects (eg. skin reaction) without sacrifice of disease control. It would be interesting to know if the modern treatment techniques have different skin reactions, and the skin dose may have been either underestimated or overestimated. The main aim of this research was to measure the dose of skin surface and internal region of breast by using a CRIS phantom and metal oxide semiconductor field effect transistor (MOSFET) under Hybrid-IMRT and FIF two treatment plans. Then we compared the measured doses of MOSFIT with the doses shown on the planning system to see if they are consistent. We also evaluated the dose difference both on skin surface and in internal region of breast by the two treatment plans. We hope that our results can provide some data which can help physicists to select the appropriate treatment plan