Properties of silica glass implanted with phosphorus ion at 50 keV for radiotherapy

Masakazu Kawashita, Fumiaki Miyaji, Tadashi Kokubo, Gikan H. Takaoka, Isao Yamada

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

A chemically durable glass containing a large amount of phosphorus is useful for in situ irradiation of cancers. It can be activated to β-emitter with 14.3d half-life by neutron bombardment. Microspheres of the activated glass injected to the tumors can irradiate β-ray directly to the tumors without giving radiation to neighboring normal tissues. In order to examine possibility for obtaining such a glass by ion implantation, P+ ion was implanted into a pure silica glass in a plate form under 50 keV to different doses. This implantation energy is estimated to give the maximum concentration of P+ ion at 48.6 nm in depth from the surface. Structural damage was produced near the surface of the glass by the ion implantation for all the doses in the range from 5 × 1016 to 1 × 1018 cm-2. The phosphorus was localized only in the regions deeper than 1.2 nm from the surface, taking a form of phosphorus colloids, for a dose of 5 × 1016 cm-2, whereas it was distributed up to the glass surface and a part of it near the surface was oxidized for doses above 1 × 1017 cm-2. The former glass little released both P and Si into water at 95°C even after 7d, whereas the latter glasses released appreciable amounts of these elements. At implantation energy of 20 keV, even a dose of 5 × 1016 cm-2 formed an oxidized phosphorus at the glass surface and gave appreciable releases of P and Si from the glass into water. This indicates that a chemically durable glass containing a larger amount of phosphorus could be obtained if P+ ion is implanted at higher energies and localized in a deeper region, even if the surface structure of the glass is damaged by the ion implantation.

Original languageEnglish
Pages (from-to)710-714
Number of pages5
JournalJournal of the Ceramic Society of Japan
Volume104
Issue number8
DOIs
Publication statusPublished - 1996

Keywords

  • Chemical durability
  • Ion implantation
  • Phosphorus
  • Radiotherapy
  • Silica glass

ASJC Scopus subject areas

  • Ceramics and Composites
  • Chemistry(all)
  • Condensed Matter Physics
  • Materials Chemistry

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