or cavity is a combination of hydrated partially acetalized polyvinyl alcohol foam particles made in the fashion described above and have particle size pore sizes and particle porosities selected to be generally suspended in a matched selected injectable biologically acceptable liquid media the homogeneous suspension generally provides for a predictable and even delivery of the particles to the selected site without clogging the delivery apparatus the liquid media has a liquid medium specific gravity generally in a range having a lower limit of about 1 0 and has an upper limit of about 1 50 although the liquid medium specific gravity may fall in a range with a lower limit of about 1 1 and an upper limit of about 1 40 or a lower limit of about 1 15 and an upper limit of about 1 40 the liquid medium may be made up of one or more members selected from the group consisting of saline solution radio opacifiers antibiotics chemotherapy drugs pharmaceuticals growth factors anti growth factors and natural and synthetic hormones or perhaps one or more imaging or contrast agents the radio opacifiers may comprise one or more iodine based imaging or contrast agents such as the well known and commercially available oxilan 300 oxilan 350 ultravist 150 ultravist 240 ultravist 300 ultravist 370 and omnipaque 350 for certain uses the liquid medium may also contain one or more anticoagulants such as heparin or one or more clotting agents.