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