Accumulation of boron compounds to tumor with polyethylene-glycol binding liposome by using neutron capture autoradiography

• Published in: Applied radiation and isotopes 2004-10, Vol.61 (4), p.639-646
• Main Authors: Yanagië, Hironobu, Ogura, Koichi, Takagi, Kenji, Maruyama, Kazuo, Matsumoto, Toshio, Sakurai, Yoshinori, Skvarc, Jure, Illic, Radomir, Kuhne, Guido, Hisa, Tomoyuki, Yoshizaki, Iwao, Kono, Kenji, Furuya, Yoshitaka, Sugiyama, Hirotaka, Kobayashi, Hisao, Ono, Koji, Nakagawa, Keiichi, Eriguchi, Masazumi
• Format: Article
• Language: English
• Subjects: 10B-compound; Animals; Autoradiography - methods; Boron - pharmacokinetics; Boron - therapeutic use; Boron neutron capture therapy (BNCT); Boron Neutron Capture Therapy - methods; Colonic Neoplasms - diagnostic imaging; Colonic Neoplasms - metabolism; CR-39 track detector; Drug Delivery Systems - methods; Isotopes - pharmacokinetics; Isotopes - therapeutic use; Liposomes - chemistry; Mice; Mice, Inbred BALB C; Mice, Nude; Neutron capture alpha-autoradiography; Neutrons - therapeutic use; Polyethylene Glycols - chemistry; Polyethylene-glycol binding-liposome (stealth liposome); Radionuclide Imaging; Radiopharmaceuticals - therapeutic use; Tissue Distribution; Transferrin-PEG-liposome
• ISSN: 0969-8043; 1872-9800
• DOI: 10.1016/j.apradiso.2004.03.109

The cytotoxic effect of boron neutron capture therapy (BNCT) is due to a nuclear reaction between 10B and thermal neutrons. It is necessary to accumulate the 10B atoms to the tumor cells selectively for effective BNCT. In order to achieve an accurate measurement of 10B concentrations in the biological samples, we employed a technique of neutron capture autoradiography (NCAR) of the sliced whole-body samples of tumor bearing mice using CR-39 plastic track detectors. The CR-39 detectors attached with samples were exposed to thermal neutrons in the thermal column of the TRIGA II reactor at the Institute for Atomic Energy, Rikkyo University and thermal neutron facility of Paul Scherer Institute(PSI). We obtained NCAR images for mice injected intraveneously by 10B-PEG liposome, 10B-transferrin-PEG liposome, or 10B-bare liposome. The 10B concentrations in the tumor tissue of mice were estimated by means of α-track density measurements. In this study, we can increase the accumulation of 10B atoms in the tumor tissues by binding polyethylene-glycol chains to the surface of liposome, which increase the retention in the blood flow and escape the phagocytosis by reticulo-endothelial systems. Therefore, we will be able to apply NCAR technique for selection of effective 10B carrier in BNCT for cancer.