Yttrium phosphate microspheres with enriched phosphorus content prepared for radiotherapy of deep-seated cancer

Toshiki Miyazaki, Toru Tanaka, Yuki Shirosaki, Masakazu Kawashita

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Ceramic microspheres composed of β-emitters are useful for in situ radiotherapy of deep-seated cancer by implantation around the tumor. In addition, microspheres 20-30 μm in diameter can combine β-emission with the embolization effect. Yttrium phosphate is an attractive candidate material for such microspheres, because both Y and P play roles as β-emitters. The half-life of 31P is known to be much larger than that of 90Y. Therefore, it is expected that yttrium phosphate microspheres with high P content can maintain a longer radiotherapy effect. In the present study, preparation of microspheres with enriched P content has been attempted by water-in-oil emulsions using polyphosphate as a starting material. Yttrium phosphate microspheres with a higher P/Y molar ratio (2.5) than in previously reported YPO4 microspheres were obtained. It was found that emulsification for sufficient time (more than 10 min) is necessary to obtain microspheres that are 20-30 μm in size. Although the microspheres released Y sparingly, they released larger amounts of P than previously reported YPO 4 microspheres in a simulated body environment. Heat treatment at moderate temperature can suppress P release to some extent. Further improvement in chemical durability through surface modification is essential for long-term clinical use.

Original languageEnglish
Pages (from-to)15259-15263
Number of pages5
JournalCeramics International
Issue number9 PART B
Publication statusPublished - 2014


  • A. Powders: chemical preparation
  • C. Chemical properties
  • E. Biomedical applications
  • Yttrium phosphate

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Process Chemistry and Technology
  • Surfaces, Coatings and Films
  • Materials Chemistry


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