title: [(18)F]Fluoro-2-deoxy-2-d-glucose versus 3'-deoxy-3'-[(18)F]fluorothymidine for defining hematopoietically active pelvic bone marrow in gynecologic patients.
abstract: OBJECTIVE
  We compared [(18)F]fluoro-2-deoxy-2-d-glucose (FDG) versus 3'-deoxy-3'-[(18)F]fluorothymidine (FLT) for the purpose of identifying active pelvic bone marrow (BM), quantifying its locational variation, and determining which technique is likely to be better for BM-sparing radiation planning.
  
  
  METHODS
  We sampled 41 patients, of which 25 underwent FDG-PET/CT only, 7 underwent FLT-PET/CT only, and 9 underwent both. Active BM subvolumes were defined as subsets of the pelvic BM with the highest standardized uptake values comprising 40%, 50%, and 60% of the total pelvic BM volume. We used the Dice similarity coefficient to quantify the percent overlap of active BM volumes of equal size. Differences in the spatial distribution of active BM were assessed using a region-growing algorithm.
  
  
  RESULTS
  For patients with both modalities, the mean Dice coefficients for the 40%, 50%, and 60% subvolumes were 0.683, 0.732, and 0.781 respectively. Comparing individual active BM subvolumes to the mean subvolume, Dice coefficients varied from 0.598-0.889 for FDG and 0.739-0.912 for FLT. Region growing analysis showed FLT-PET defined more highly clustered active BM subvolumes.
  
  
  CONCLUSIONS
  Within the limitations of a small sample size, we found significant agreement between FDG-PET and FLT-PET; however, FLT-PET had significantly less individual variation and is likely to be superior to FDG-PET for BM-sparing radiotherapy.
authors.affiliation: Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, United States.
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: Wyss
authors.affiliation: Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, United States.
authors.forename: Ruben
authors.initials: R
authors.lastname: Carmona
authors.affiliation: Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, United States.
authors.forename: Roshan A
authors.initials: RA
authors.lastname: Karunamuni
authors.affiliation: Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, United States.
authors.forename: Jakub
authors.initials: J
authors.lastname: Pritz
authors.affiliation: Department of Radiology, Division of Nuclear Medicine, University of California San Diego, La Jolla, United States.
authors.forename: Carl K
authors.initials: CK
authors.lastname: Hoh
authors.affiliation: Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, United States. Electronic address: lmell@ucsd.edu.
authors.forename: Loren K
authors.initials: LK
authors.lastname: Mell
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001853:Bone Marrow / Q000000981:diagnostic imaging / Q000528:radiation effects*; D015224:Dideoxynucleosides; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D059351:Organ Sparing Treatments / Q000379:methods; D010384:Pelvic Bones / Q000000981:diagnostic imaging / Q000528:radiation effects; D049268:Positron-Emission Tomography / Q000379:methods; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods; D002583:Uterine Cervical Neoplasms / Q000532:radiotherapy*
chemical_list: D015224:Dideoxynucleosides; D019788:Fluorodeoxyglucose F18
keywords: (18)F-FDG; (18)F-FLT; Active bone marrow; Radiotherapy planning