My grandpa is suffering from illness related to kidney he has to do cityscan before that a risky kind of injectio named dye which is risky what to do?

Check renal function: It sounds like there is a concern whether to do the ct scan with IV contrast. The doctor should check the kidney function by calculating the estimated glomerular filtration rate (egfr). This is derived from the creatinine level, age, and ethnic factors. If over 60, it's ok to give contrast (assuming not allergic). If less than 30, shouldn't get contrast. If 30-60, needs to be IV hydrated.