17540
Towards this , a novel approach was envisaged to synthesize a ( 99m ) Tc labeled dimeric RGD derivative using a RGD monomer and [ ( 99m ) TcN ] ( + 2 ) intermediate .
 ( 99m ) Tc, [ ( 99m ) TcN ] ( + 2 )
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 ( 99m ) Tc, [ ( 99m ) TcN ] ( + 2 )