The Study Of Craniospinal SIMRT

Objective To study sIMRT technique for the spinal component of craniospinalirradiation （CSI）, to compare this technique with conventional plan （3DCRT）.Five previously treated patients were used to genera to3DCRT,3F-s IMRT(sIMRT_3f) and5F-sIMRT (sIMRT_5f). The prescribed dose is36Gy to the planning targetvolume （PTV） in20fractiuons..The dose distributions of target volume and normaltissues,and hereogenenouse index （HI） were ananlyzed using the dose-volumehistogram for these technique. The total monitor units（MU）were also analyzed tocompare the execution time indirectly. For3D-CRT plans, the region of theneighbouring fields can only receive70%of the prescribed dose, the maximum dosedelivered in the NT was increased by approximately140%to the prescribed dose. Thehomogeneity index（HI） of3DCRT,3F-sIMRT3f,5F-sIMRT5f was0.18±0.02、0.09±0.01、0.08±0.01（t=7.8、7.65,P<0.05）.sIMRT can protect the organs at risk betterthan3DCRT.The mean of total MU for3DCRT,3F-sIMRT3f,5F-sIMRT5f was640±78MU、1100±106MU、1160±129MU.sIMRT can improve target dose uniformity, protect the organs at risk wellcompared to the3DCRT CSI technique.