LEARNit Dictionary
tracer
noun
/ˈtreɪsə(r)/
UK
/ˈtreɪsər/
US
1
a bullet or shell(= a kind of bomb) that leaves a line of smoke or flame behind it
گلوله ردیاب, مرمی ردیاب
2
a radioactive substance that can be seen in the human body and is used to find out what is happening inside the body
ایزوتوپ نشاندار, ردیاب (مواد رادیواکتیو)
Radioactive tracers have been used to map the metabolic activity of the brain.