There are {HEAD ~ a number} of methods for producing images of {TAIL ~ internal structures} of a body 
There are { HEAD ~ a number } of methods for producing images of { TAIL ~ internal structures } of a body
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH