The grid of this invention is of {HEAD ~ an air core type}, eliminating {TAIL ~ the x ray transparent material} of the prior known grids 
The grid of this invention is of { HEAD ~ an air core type } , eliminating { TAIL ~ the x ray transparent material } of the prior known grids
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH