title: Variations in (18)F-FDG uptake in breast cancer depending on PET/CT acquisition position.
abstract: OBJECTIVE
  To evaluate the variability of quantitative 2-[(18)F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography (PET) combined with computed tomography (CT) parameters depending on acquisition position in a dual-position protocol for breast cancers.
  
  
  METHODS
  For initial staging work-up, whole-body PET/CT was first acquired in a supine position, and then followed by a regional breast scan in a prone position. The maximum standardised uptake value (SUVmax), metabolic tumour volume (MTV), and total lesion glycolysis (TLG) were measured on both acquisition positions. MTV50 and TLG50 were calculated with a threshold set to be 50% of SUVmax, and MTV2.5 and TLG2.5 with a fixed SUV threshold of 2.5.
  
  
  RESULTS
  The median SUVmax of breast cancers measured on the supine scans was 4.88, and 4.49 on the prone images (p<0.05). MTV and TLG also yielded significantly lower values from supine images. Regarding the tendency for the acquisition position to yield different results, a significant disagreement was observed between SUVmax and MTV50 and between SUVmax and TLG50 (kappa = -0156 and -0.001, respectively), while MTV2.5 and TLG2.5 showed a fair to moderate agreement with SUVmax (kappa = 0.311 and 0.416, respectively).
  
  
  CONCLUSIONS
  SUVmax, MTV, and TLG yielded lower values when acquired in the prone position compared to in the supine position. This observation could be due to the partial volume effect. When using 50% of SUVmax as a threshold, there was a significant discordance between SUVmax and volumetric parameters. Thus, acquisition position may affect quantitative PET/CT parameters and the clinical implications.
authors.affiliation: Department of Nuclear Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: J H
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Nuclear Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: T J
authors.initials: TJ
authors.lastname: Jeon
authors.affiliation: Department of Surgery, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: S G
authors.initials: SG
authors.lastname: Ahn
authors.affiliation: Department of Surgery, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: J
authors.initials: J
authors.lastname: Jeong
authors.affiliation: Department of Nuclear Medicine, College of Medicine, Chung-Ang University, Seoul, South Korea. Electronic address: ethmoid@hanmail.net.
authors.forename: J W
authors.initials: JW
authors.lastname: Seok
authors.affiliation: Department of Nuclear Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea. Electronic address: ydmcra@gmail.com.
authors.forename: Y H
authors.initials: YH
authors.lastname: Ryu
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008207:Lymphatic Metastasis; D008875:Middle Aged; D064847:Multimodal Imaging; D009367:Neoplasm Staging; D056888:Patient Positioning; D049268:Positron-Emission Tomography / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18