静脉造影常使用的造影剂是（）What is the commonly used contrast medium for phlebography？

静脉造影常使用的造影剂是（）What is the commonly used contrast medium for phlebography？
A.二氧化碳Carbon dioxide
B.硫酸钡Barium sulfate
C.碘造影剂Iodine contrast agent
D.空气Air
正确答案：碘造影剂Iodine contrast agent