The effective radiation dose were 0.44 0.25 mSv and 0.94 0.42 mSv for iomeprol 270 and iopromide 370 in low weight subgroups , and 1.17 0.30 mSv and 2.37 0.66 mSv in high weight subgroups , respectively , reflecting dose savings of 53.2 % ( P < 0.01 ) and 50.6 % ( P < 0.01 ) , respectively .