Low density microcellular foams containing dispersed high atomic number material have been produced. The work done by R. Simandl et al., using phase inversion of a binary solvent system and poly (4-methyl 1-pentene) to produce microporous polymer foams was successfully duplicated.1 To enhance the diagnostic properties of the material, molybdenum, a high Z material, was dispersed throughout the foam. We have been able to incorporate the molybdenum into the foam structure while maintaining a relatively low bulk density. Foam samples with initial molybdenum concentrations up to 25 wt % and with bulk densities as low as 15 mg/cc have been produced. The uniformity of the molybdenum dispersion has not yet been quantitatively characterized but does vary from sample to sample.