Visualization of pi- and pi+ stopping density distributions in one and two dimensions.

A technique suitable for mapping pi+/- stopping density distributions in patients or phantoms is described. As a position sensitive detector a multiwire proportional chamber with a slit or a hole collimator in front was applied. Results using a water and a Rando phantom are presented for various momenta and momentum band widths of the pi+/- beam. To our knowledge the two-dimensional visualization of a pi- stopping density distribution was realized for the first time.