title: Semiquantitative Analysis of the Biodistribution of the Combined ¹⁸F-NaF and ¹⁸F-FDG Administration for PET/CT Imaging.
abstract: In this study, we evaluated the biodistribution of the (18)F(-)/(18)F-FDG administration, compared with separate (18)F-NaF and (18)F-FDG administrations. We also estimated the interaction of (18)F-NaF and (18)F-FDG in the (18)F(-)/(18)F-FDG administration by semiquantitative analysis.
  
  
  METHODS
  We retrospectively analyzed the data of 49 patients (39 men, 10 women; mean age ± SD, 59.3 ± 15.2 y) who underwent separate (18)F-FDG PET/CT and (18)F-NaF PET/CT scans as well as (18)F(-)/(18)F-FDG PET/CT sequentially. The most common primary diagnosis was prostate cancer (n = 28), followed by sarcoma (n = 9) and breast cancer (n = 6). The mean standardized uptake values (SUVs) were recorded for 18 organs in all patients, and maximum SUV and mean SUV were recorded for all the identified malignant lesions. We also estimated the (18)F(-)/(18)F-FDG uptake as the sum of (18)F-FDG uptake and adjusted (18)F-NaF uptake based on the ratio of (18)F-NaF injected dose in (18)F(-)/(18)F-FDG PET/CT. Lastly, we compared the results to explore the interaction of (18)F-FDG and (18)F-NaF uptake in the (18)F(-)/(18)F-FDG scan.
  
  
  RESULTS
  The (18)F(-)/(18)F-FDG uptake in the cerebral cortex, cerebellum, parotid grand, myocardium, and bowel mostly reflected the (18)F-FDG uptake, whereas the uptake in the other analyzed structures was influenced by both the (18)F-FDG and the (18)F-NaF uptake. The (18)F(-)/(18)F-FDG uptake in extraskeletal lesions showed no significant difference when compared with the uptake from the separate (18)F-FDG scan. The (18)F(-)/(18)F-FDG uptake in skeletal lesions reflected mostly the (18)F-NaF uptake. The tumor-to-background ratio of (18)F(-)/(18)F-FDG in extraskeletal lesions showed no significant difference when compared with that from (18)F-FDG alone (P = 0.73). For skeletal lesions, the tumor-to-background ratio of (18)F(-)/(18)F-FDG was lower than that from (18)F-NaF alone (P < 0.001); however, this difference did not result in missed skeletal lesions on the (18)F(-)/(18)F-FDG scan.
  
  
  CONCLUSIONS
  The understanding of the biodistribution of radiopharmaceuticals and the lesion uptake of the (18)F(-)/(18)F-FDG scan as well as the variations compared with the uptake on the separate (18)F-FDG PET/CT and (18)F-NaF PET/CT are valuable for more in-depth evaluation of the combined scanning technique.
authors.affiliation: Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Stanford University, Stanford, California; and Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, California.
authors.forename: Ryogo
authors.initials: R
authors.lastname: Minamimoto
authors.affiliation: Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Stanford University, Stanford, California; and.
authors.forename: Camila
authors.initials: C
authors.lastname: Mosci
authors.affiliation: Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Stanford University, Stanford, California; and Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, California.
authors.forename: Mehran
authors.initials: M
authors.lastname: Jamali
authors.affiliation: Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Stanford University, Stanford, California; and.
authors.forename: Amir
authors.initials: A
authors.lastname: Barkhodari
authors.affiliation: Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, California.
authors.forename: Frezghi
authors.initials: F
authors.lastname: Habte
authors.affiliation: Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Stanford University, Stanford, California; and.
authors.forename: Tatianie
authors.initials: T
authors.lastname: Jackson
authors.affiliation: Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Stanford University, Stanford, California; and.
authors.forename: Erik
authors.initials: E
authors.lastname: Mittra
authors.affiliation: Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Stanford University, Stanford, California; and Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, California.
authors.forename: Sanjiv Sam
authors.initials: SS
authors.lastname: Gambhir
authors.affiliation: Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Stanford University, Stanford, California; and aiagaru@stanford.edu.
authors.forename: Andrei
authors.initials: A
authors.lastname: Iagaru
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001692:Biological Transport; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000008:administration & dosage / Q000493:pharmacokinetics*; D006801:Humans; D007267:Injections; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D012189:Retrospective Studies; D012969:Sodium Fluoride / Q000008:administration & dosage / Q000493:pharmacokinetics*; D013997:Time Factors; D014018:Tissue Distribution; D014057:Tomography, X-Ray Computed; D055815:Young Adult
chemical_list: D019788:Fluorodeoxyglucose F18; D012969:Sodium Fluoride
keywords: 18F-FDG; 18F-NaF; PET/CT; SUV