Preparation of ceramic microspheres for in situ radiotherapy of deep-seated cancer.

Radiotherapy is one of the most effective treatments for cancers. However, external irradiation provides only small doses to deep-seated cancers, and often causes damage to healthy tissues. It has been reported that 20-30 microm diameter 17Y(2)O(3)-19Al(2)O(3)-64SiO(2) (mol%) glass microspheres are useful for the in situ irradiation of cancers. Yttrium-89 (89Y) in this glass can be neutron bombarded to form the beta-emitter 90Y (half-life=64.1h). When injected in the vicinity of the cancer, such activated glass microspheres can provide a large localized dose of beta-radiation. The Y(2)O(3) content of the glass in the microspheres is limited to only 17 mol%. Chemically durable microspheres with a higher Y(2)O(3) content need to be developed. Phosphorus-31 (31P) with 100% natural abundance can also be activated by neutron bombardment to form the beta-emitter 32P (half-life=14.3d). Chemically durable microspheres containing a high phosphorus content are expected to be more effective for cancer treatment. We prepared pure Y(2)O(3) and YPO(4) microspheres using a high-frequency induction thermal plasma melting technique, and investigated the resulting structure and chemical durability. We successfully prepared smooth, highly spherical polycrystalline Y(2)O(3) and YPO(4) microspheres with diameters in the range 20-30 microm. Both the Y(2)O(3) and YPO(4) microspheres showed high chemical durability in saline solutions buffered at pH=6 and 7. These microspheres are expected to be more effective than the conventional glass microspheres for the in situ radiotherapy of cancer.

[1]  G. Lin,et al.  Yttrium-90 Glass Microspheres Injected VIA the Portal Vein , 1993, Acta radiologica.

[2]  J. Juni,et al.  Effects of hepatic arterial yttrium 90 glass microspheres in dogs , 1988, Cancer.

[3]  Huiyang Zhao,et al.  An experimental study and clinical pilot trials on Yttrium‐90 glass microspheres through the hepatic artery for treatment of primary liver cancer , 1993, Cancer.

[4]  G. Hahn,et al.  Comparison between tumor pH and cell sensitivity to heat in RIF-1 tumors. , 1989, Cancer research.

[5]  S. J. Wang,et al.  Intra-tumoural injection of 90Y microspheres into an animal model of hepatoma , 2001, Nuclear medicine communications.

[6]  M. Burton,et al.  Intraoperative dosimetry of 90Y in liver tissue. , 1989, International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology.

[7]  D. Kerr,et al.  Glass yttrium-90 microspheres for patients with colorectal liver metastases. , 1992, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[8]  B. Tsao,et al.  Monocytes can be induced by lipopolysaccharide-triggered T lymphocytes to express functional factor VII/VIIa protease activity , 1984, The Journal of experimental medicine.

[9]  S. Houle,et al.  Hepatocellular carcinoma: pilot trial of treatment with Y-90 microspheres. , 1989, Radiology.

[10]  P. Bret,et al.  Hepatic malignancies: improved treatment with intraarterial Y-90. , 1988, Radiology.

[11]  D. Day,et al.  Chemical durability of Y2O3-Al2O3-SiO2 glasses for the in vivo delivery of beta radiation. , 1993, Journal of biomedical materials research.

[12]  R. C. Weast.  CRC Handbook of Chemistry and Physics , 1973 .

[13]  Delbert E. Day,et al.  Glass Properties in the Yttria‐Alumina‐Silica System , 1987 .

[14]  T. Edgington,et al.  Influence of mutations in tissue factor on the fine specificity of macromolecular substrate activation. , 1997, The Biochemical journal.

[15]  E. Felix,et al.  Intraarterial yttrium 90 in the treatment of hepatic malignancy. , 1982, Radiology.

[16]  W. Ensminger,et al.  Hepatic radioembolization with yttrium-90 containing glass microspheres: preliminary results and clinical follow-up. , 1994, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[17]  P. Liang,et al.  Ultrasound-guided internal radiotherapy using yttrium-90-glass microspheres for liver malignancies. , 1997, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[18]  S. Houle,et al.  A phase I dose escalation trial of yttrium‐90 microspheres in the treatment of primary hepatocellular carcinoma , 1992, Cancer.

[19]  J. Sun,et al.  Hepatic radioembolization with Yttrium-90 glass microspheres for treatment of primary liver cancer. , 1999, Chinese medical journal.