Objective To study the application value of iodixanol in gemstone spectral imaging with low CT dosage.Methods Forty hundred and twenty -six cancer patients with normal kidney function were selected .All of them underwent enhanced gemstone spectral CT scan with low dosage .They were individed into two groups with random number table,including observation group(n=213) and control group(n=213).The observation group was injected isotonic iodixanol ( 270 mgI/mL ) intravenously , while the control group was injected hypertronic iohexol (350mgI/mL) intravenously.With the same injection speed,the acute adverse reaction within 1h and delayed adverse reaction between 1h～7d were recorded.Meanwhile,the changes of Scr and Ccr ,the occurrence rate of contrast -induced nephropathy(CIN) and short -term prognosis were also recorded.Results Fifty-three patients occurred acute adverse reaction,among them 18 cases(8.45％) were in the observation group,35 cases(16.43％) were in the control group,there was statistically significant difference between the two groups (χ2 =10.791,P<0.05).Three patients(1.50％) of the control group occurred delayed adverse reaction ,no one was in the observation group .The adverse reaction disappeared after some time .Two kinds of contrast media caused slight increase of Scr and decrease of Ccr,but there were no statistically significant differences between them (all P>0.05).Conclusion The intrave-nous injection of iodixanol can reduce the occurrence of acute adverse reaction ,will not increase the incidence of CIN . It can be used safely .