P-31 can be activated to β-emitter P-32 with 14.3 days half-life by neutron bombardment. A chemically durable glass containing a large amount of phosphorus is believed to be useful for in situ irradiation of cancers. When they are subjected to neutron bombardment and injected around the tumor, they can irradiate directly a cancer without giving radiation to normal tissues. In this study, a pure silica glass was implanted with phosphorus and nitrogen ions by a dose of 5×1016 cm-2 at 30 and 14 keV, respectively, and subjected to two-step heat treatments at 400°C in H2 and then at 900°C in O2. In the first step, phosphorus colloids were grown in the silica glass. In the second step, the colloids were encapsulated in a SiO2-P2O5 glass film formed at their surfaces and the structural damage produced by ion implantation was healed. It is speculated that the implanted nitrogen forms silicon oxynitride in the glass, strengthening the silica network and suppressing the evaporation of phosphorus during heat treatment. The prepared glass did not dissolve phosphorus or silicon, even after soaking in distilled water at 95°C for 7 days, and hence is believed to be useful for radiotherapy of cancers.
|Number of pages||6|
|Journal||Journal of Materials Science: Materials in Medicine|
|Publication status||Published - 1995 Oct 1|
ASJC Scopus subject areas
- Biomedical Engineering