6917
The [ (1) (1) C - carbonyl ] - radiotracers were evaluated in vitro and ex vivo in rats as potential FAAH imaging agents for positron emission tomography ( PET ) .
 Chemical: (1) (1) C - carbonyl
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: (1) (1) C - carbonyl