title: Assessment of10B concentration in boron neutron capture therapy: potential of image-guided therapy using18FBPA PET.
abstract: OBJECTIVE
  In boron neutron capture therapy (BNCT) for cancer, the accurate estimation of10B tissue concentrations, especially in neighboring normal organs, is important to avoid adverse effects. The10B concentration in normal organs after loading with10B, however, has not been established in humans. In this study, we performed 4-borono-2-[18F]-fluoro-phenylalanine (18FBPA) PET in healthy volunteers and estimated the chronological changes in the10B concentrations of normal organs.
  
  
  METHODS
  In 6 healthy volunteers, whole-body18FBPA PET scans were repeated 7 times during 1 h, and the mean18FBPA distributions of 13 organs were measured. Based on the18FBPA PET data, we then estimated the changes in the10B concentrations of the organs when the injection of a therapeutic dose of10BPA-fructose complex (10BPA-fr; 30 g, 500 mg/kg body weight) was assumed.
  
  
  RESULTS
  The maximum mean18FBPA concentrations were reached at 2-6 min after injection in all the organs except the brain and urinary bladder. The mean18FBPA concentration in normal brain plateaued at 24 min after injection. When the injection of a therapeutic dose of10BPA-fr was assumed, the estimated mean10B concentration in the kidney increased to 126.1 ± 24.2 ppm at 3 min after injection and then rapidly decreased to 30.9 ± 7.4 ppm at 53 min. The estimated mean10B concentration in the bladder gradually increased and reached 383.6 ± 214.7 ppm at 51 min. The mean10B concentration in the brain was estimated to be 7.6 ± 1.5 ppm at 57 min.
  
  
  CONCLUSIONS
  18FBPA PET has a potential to estimate10B concentration of normal organs before neutron irradiation of BNCT when several assumptions are validated in the future studies.
authors: Department of Molecular Imaging in Medicine, Osaka University Graduate School of Medicine, Suita, Japan. eku@mi.med.osaka-u.ac.jp.|Department of Nuclear Medicine and Tracer Kinetics, Osaka University Graduate School of Medicine, Suita, Japan. eku@mi.med.osaka-u.ac.jp.
authors: Eku
authors: E
authors: Shimosegawa
authors: Department of Nuclear Medicine and Tracer Kinetics, Osaka University Graduate School of Medicine, Suita, Japan.
authors: Kayako
authors: K
authors: Isohashi
authors: Osaka University Hospital, Suita, Japan.
authors: Sadahiro
authors: S
authors: Naka
authors: Osaka University Hospital, Suita, Japan.
authors: Genki
authors: G
authors: Horitsugi
authors: Department of Nuclear Medicine and Tracer Kinetics, Osaka University Graduate School of Medicine, Suita, Japan.
authors: Jun
authors: J
authors: Hatazawa
mesh_terms: D000328:Adult; D001895:Boron / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D001896:Boron Compounds; D016754:Boron Neutron Capture Therapy; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007554:Isotopes; D008297:Male; D008875:Middle Aged; D010649:Phenylalanine / Q000031:analogs & derivatives; D049268:Positron-Emission Tomography; D011879:Radiotherapy Dosage; D061089:Radiotherapy, Image-Guided; D014018:Tissue Distribution; D055815:Young Adult
chemical_list: D001896:Boron Compounds; D007554:Isotopes; C072915:4-borono-2-fluorophenylalanine; D010649:Phenylalanine; D001895:Boron
keywords: 10B; 10BPA; 18FBPA; BNCT; PET