A unique in vivo assessment of 4-[10B]borono-L-phenylalanine in tumour tissues for boron neutron capture therapy of malignant melanomas using positron emission tomography and 4-borono-2-[18F]fluoro-L-phenylalanine.
A unique in vivo approach to assessing the concentrations of 4-[10B]borono-L-phenylalanine (L-BPA), a melanoma targeting compound for boron neutron capture therapy (BNCT), was investigated using L-BPA labelled with positron-emitting 18F (half-life = 110 min), i.e., 4-[10B]borono-2-[18F]fluoro-L-phenylalanine (L-[18F]FBPA). High melanoma uptake of L-[18F]FBPA was reduced slightly by competition with L-BPA in the two animal models of the murine B16 melanoma and the melanotic Greene's melanoma No. 179 in hamsters. In mice given L-[18F]FBPA and L-BPA, the concentrations of 10B in B16 estimated from 18F radioactivity were lower than those measured by inductively coupled plasma-atomic emission spectroscopy. Lower estimated values were dependent on the time after injection and on the loading dose of L-BPA. The estimated 10B concentrations for Green's melanomas were comparable to the measured values. Positron emission tomography (PET) using L-[18F]FBPA allowed Greene's melanomas to be clearly visualized. In conclusion, when L-[18F]FBPA is used as a probe for L-BPA in BNCT of malignant melanomas, the melanoma can be localized and the 10B concentrations in tissues can be assessed in vivo using 18F radioactivity by PET.
Ishiwata
K
K
Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan.
Shiono
M
M
Kubota
K
K
Yoshino
K
K
Hatazawa
J
J
Ido
T
T
Honda
C
C
Ichihashi
M
M
Mishima
Y
Y
D000818:Animals; D001896:Boron Compounds / Q000493:pharmacokinetics* / Q000627:therapeutic use; D006224:Cricetinae; D005462:Fluorine Radioisotopes; D008546:Melanoma, Experimental / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D008647:Mesocricetus; D051379:Mice; D008810:Mice, Inbred C57BL; D009368:Neoplasm Transplantation; D017247:Neutron Capture Therapy; D010649:Phenylalanine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000627:therapeutic use; D014018:Tissue Distribution; D014055:Tomography, Emission-Computed
D001896:Boron Compounds; D005462:Fluorine Radioisotopes; C072915:4-borono-2-fluorophenylalanine; D010649:Phenylalanine; C033685:4-boronophenylalanine