TY - JOUR
T1 - Yttrium phosphate microspheres with enriched phosphorus content prepared for radiotherapy of deep-seated cancer
AU - Miyazaki, Toshiki
AU - Tanaka, Toru
AU - Shirosaki, Yuki
AU - Kawashita, Masakazu
N1 - Funding Information:
This work was supported by a Grant-in-Aid for Scientific Research on Innovative Areas for “Fusion Materials: Creative Development of Materials and Exploration of Their Function through Molecular Control” (No. 2206 ) from the Ministry of Education, Culture, Sports, Science and Technology , Japan ( MEXT ).
PY - 2014
Y1 - 2014
N2 - 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.
AB - 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.
KW - A. Powders: chemical preparation
KW - C. Chemical properties
KW - E. Biomedical applications
KW - Yttrium phosphate
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U2 - 10.1016/j.ceramint.2014.07.018
DO - 10.1016/j.ceramint.2014.07.018
M3 - Article
AN - SCOPUS:84905905859
VL - 40
SP - 15259
EP - 15263
JO - Ceramics International
JF - Ceramics International
SN - 0272-8842
IS - 9 PART B
ER -
