Page 53 - Fisica In Medicina n° 1/2017

^Äëíê~Åí=cáëáÅá= =OARs doses (Dmax and dose at the threshold volume according to AAPM TG101) were evaluated. Furthermore, the attenuation of the dolphin was evaluated measuring the plans with the Delta4 (Scandidos, Sweden) detector with and without the Dolphin inserted in the Linac.ResultsThe percentage differences between Compass and Monaco computation were -4.2 ±1.7 % for D98% (min -7.1% , max -1.1%), -1.8±1.6 % (min -4.0% , max 1.2%) for mean dose and -0.5 ±1.5 % (min -2.3% , max 2.8%) for D2% .Table 1 shows the results of the comparison between Compass plan computation and Compass reconstructed doses. The PTV average gamma was 0.64±0.12; the mean percentage differences of V80%, D98%, mean dose and D2% were inferior to 3%. The difference in Gy for OARs were under or equal to 1 Gy, except for D(4cc) of trachea (1.15 Gy). The maximum difference was found for rib Dmax (4.4 Gy).The evaluation of the median dose in Delta 4 with and without the Dolphin allowed the calculation of the system attenuation: a value of 10.5±0.5 % was found. This procedure permit an evaluation in a clinical geometry.44