For example, a CT image obtained with an X ray CT apparatus and a PET image obtained with PET are examples of {HEAD ~ medical images} obtained by {TAIL ~ each different modality} 
obtained by
For example , a CT image obtained with an X ray CT apparatus and a PET image obtained with PET are examples of { HEAD ~ medical images } obtained by { TAIL ~ each different modality }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL