Therefore, grid structure that has a high percentage of open area, but with walls that are highly attenuating for {HEAD ~ x rays} at {TAIL ~ the appropriate energy} is an efficient geometry for this purpose 
at
Therefore , grid structure that has a high percentage of open area , but with walls that are highly attenuating for { HEAD ~ x rays } at { TAIL ~ the appropriate energy } is an efficient geometry for this purpose
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 TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH