An Attempt to a New Neutron Capture Therapy Using Rhodium—The Anti-tumor Method Based on Beta Ray

• Published in: RADIOISOTOPES Vol. 73; no. 1; pp. 9 - 21
• Main Authors: Hou, Xuan, Yanagie, Hironobu, Matsukawa, Takehisa, Kubota, Ayano, Yang, Daibing, Yanagawa, Masashi, Yamaguchi, Haruo, Ono, Minoru, Cabral, Horacio, Shimazoe, Kenji, Takahashi, Hiroyuki
• Format: Journal Article
• Language: English
• Published: Japan Radioisotope Association 15.03.2024
• Subjects: beta ray; liposome; Neutron Capture Therapy (NCT); rhodium
• ISSN: 0033-8303; 1884-4111
• DOI: 10.3769/radioisotopes.73.9

Neutron capture therapy (NCT) uses secondary particle to treat tumor. Boron has been applied to NCT in clinics, and gadolinium has also attracted the attention. Our group attempted a new candidate element, rhodium, because of its advantages, such as 100% natural abundance, long range (beta ray), neutron cross-section peak, and fitness to accelerator-based neutrons. To reduce toxicity and increase tumor accumulation, rhodium encapsulated liposomes (Rh-Lip) were synthesized. After 24 h exposure to rhodium solution, the cell viability increased to 90% when the rhodium concentration was diluted to 0.063 mg/mL; in contrast, it was up to 90% when rhodium concentration was diluted to 0.25 mg/mL in the Rh-Lip group. Moreover, in the Rh-Lip group, 387.3 ppm rhodium remained in the tumor 3 h after administration, but only 42.6 ppm remained in the rhodium solution group. After neutron irradiation, Rh-Lip showed a slower tumor growth rate and damage to tumor cells from pathological analysis, suggesting that rhodium is a potential element for NCT.