{HEAD ~ Various derivatives} of {TAIL ~ DTPA} , including those disclosed herein, are preferred chelators for such ions in compounds according to the present invention 
of
{ HEAD ~ Various derivatives } of { TAIL ~ DTPA } , including those disclosed herein , are preferred chelators for such ions in compounds according to the present invention
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH