Concepedia

Abstract

Under certain conditions, it appears that focusing collimator systems can be designed for.511 Mev radiation which are superior to coincidence systems by factors of 2 to 10 (depending on resolution) for midline tumors. These factors increase for tumors not on the midline. Making the further assumption of equal numbers of photons produced/cm/sup 3/-sec for all systems, the figure of merit for focusing collimator systems increases with decreasing gamma energy down to 200 Mev, the low energy limit of this investigation. Therefore it is generally concluded that the advantages of low energy gamma radiation for brain scanning have not yet been fully exploited. (auth)