Double-focused micro-Multileaf Collimator (μMLC) is able to create radiation fields having sharper dose gradients at the field edges than common MLC. Therefore, μMLC has been used for the stereotactic radio surgery (SRS) and Stereotactic Radiotherapy (SRT). We evaluated the dosimetric characteristics of a double focused Dynamic-μMLC (DMLC) attached to the Elekta Synergy linear accelerator. For this study, the dosimetric parameters including, Percent Depth Dose (PDD), Leaf leakage and penumbra, have been measured by using of the radiochromic films (GafChromic EBT2), EDGE diode detector and three-dimensional water phantom. All datas were measured on 6 MV x-ray. As a result, The DMLC shows transmission below to 1% and because of double-focused construction of the DMLC, the penumbras of fields with DMLC are independent from the field sizes. In this paper, the resulting dosimetric evaluations proved the applicability of the DMLC attached to the Elekta Synergy linear accelerator.

KeywordsDynamic micro-Multileaf Collimator, PDD, Leaf transmission, Penumbra