Dosimetric Comparison Of Different RapidArc Treatment Options For Radiotherapy Of Multiple Brain Metastasis Tumors

Purpose：To compare the target dose distribution and the doses in normaltissues exposed using different RapidArc treatment options in the treatment ofmultiple brain metastasis tumors and explore the ideal model in theradiotherapy.Materials and Methods：Fifteen patients with4to8brain metastasistumor were choosed to design2RapidArc plans. The patients in one group ofnamed sequential integrated tumor boost were received by3-dimensionalbilateral WBRT (40Gy/20fractions), followed by sequential RapidArc tumorboost (20Gy/10fractions). The patients in other group of named simultaneousintegrated tumor boost were received by RapidArc WBRT (40Gy/20fractions)with simultaneous integrated boost to tumors (60Gy/20fractions). The planwas applied with Eclipse treatment planning system10.0. Target dosedistribution and the exposed doses in normal tissue will be compared withSPSS.Results：Two plans can all meet the clinical requirements. Dmax, Dmean,V20,V30and V40of parotid, external auditory canal and scalp in thesimultaneous integrated tumor boost group were lower than those in the other group. The same, the V45,V50and V55of the normal brain tissue were lower thanthose in it.Conclusion： RapidArc technique can meet the clinical demand formultiple brain metastasis tumors. There was no differenece between the twotreatment options in CI, HI and the doses which lens, optic nerve and chiasm,stem received. RapidArc WBRT with simultaneous integrated boost has anadvantage in the exposed doses of parotid, external auditory canal, scalp andnormal brain tissue.