title: Optimizing the interval between G-CSF therapy and F-18 FDG PET imaging in children and young adults receiving chemotherapy for sarcoma.
abstract: BACKGROUND
  Granulocyte colony-stimulating factors (G-CSF) speed recovery from chemotherapy-induced myelosuppression but the marrow stimulation they cause can interfere with interpretation of F-18 fluorodeoxyglucose positron emission tomography (F-18 FDG PET) exams.
  
  
  OBJECTIVE
  To assess the frequency of interfering G-CSF-induced bone marrow activity on FDG PET imaging in children and young adults with Ewing sarcoma and rhabdomyosarcoma and to define an interval between G-CSF administration and FDG PET imaging that limits marrow interference.
  
  
  METHODS
  Blinded, retrospective review of FDG PET exams performed in patients treated with long-acting G-CSF as part of their chemotherapeutic regimen. Exams were subjectively scored by two reviewers (R1 and R2) who assessed the level of marrow uptake of FDG and measured standardized uptake values in the marrow, liver, spleen and blood pool. FDG PET findings were correlated with time since G-CSF administration and with blood cell counts.
  
  
  RESULTS
  Thirty-eight FDG PET exams performed in 17 patients were reviewed with 47.4% (18/38) of exams having marrow uptake of FDG sufficient to interfere with image interpretation. Primary predictors of marrow uptake of FDG were patient age (P=0.0037) and time since G-CSF exposure (P=0.0028 for subjective marrow uptake of FDG, P=0.008 [R1] and P=0.004 [R2] for measured maximum standardized uptake value (SUVmax)). The median interval between G-CSF administration and PET imaging in cases with marrow activity considered normal or not likely to interfere was 19.5 days (range: 7-55 days).
  
  
  CONCLUSIONS
  In pediatric and young adult patients with Ewing sarcoma and rhabdomyosarcoma, an interval of 20 days between administration of the long-acting form of G-CSF and FDG PET imaging should limit interference by stimulated marrow.
authors: Department of Radiology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., MLC 5031, Cincinnati, OH, 45229-3026, USA, andrew.trout@cchmc.org.
authors: Andrew T
authors: AT
authors: Trout
authors: Susan E
authors: SE
authors: Sharp
authors: Brian K
authors: BK
authors: Turpin
authors: Bin
authors: B
authors: Zhang
authors: Michael J
authors: MJ
authors: Gelfand
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004334:Drug Administration Schedule; D005260:Female; D019788:Fluorodeoxyglucose F18; D016179:Granulocyte Colony-Stimulating Factor / Q000008:administration & dosage*; D006801:Humans; D007223:Infant; D008297:Male; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012509:Sarcoma / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D051598:Whole Body Imaging; D055815:Young Adult
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D016179:Granulocyte Colony-Stimulating Factor
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