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