title: Tumour hypoxia imaging with 18F-fluoroazomycinarabinofuranoside PET/CT in patients with locally advanced rectal cancer.
abstract: OBJECTIVE
  The aim of this study was to investigate the feasibility of F-fluoroazomycinarabinofuranoside (F-FAZA) positron emission tomography (PET)/computed tomography (CT) in patients with locally advanced rectal cancer.
  
  
  METHODS
  The study included 14 patients with locally advanced rectal cancer. Before chemoradiotherapy, PET/CT with F-FAZA was performed with static 15 min images 2 h after injection of F-FAZA. Attenuation correction was obtained with a low-dose CT, and a contrast-enhanced CT was performed immediately after the PET scan.
  
  
  RESULTS
  F-FAZA uptake [mean and maximum standardized uptake value (SUVmean) and (SUVmax)] was significantly higher in rectal tumours than in both muscles (P<0.003) and normal intestinal walls (P<5×10). The tumour to muscle (T/M) ratios ranged from 1.19 to 3.05 with a mean of 1.97, whereas the tumour to intestinal wall (T/I) ratios had values of 1.73-5.81 with a mean of 2.83. Intense activity accumulating in the bladder produced obvious scattered activity, which spread into the surrounding tissue. Tumour volumes excluding scatter were therefore determined, in which the SUVmax and SUVmean were also significantly higher than in both muscles (P<0.004) and normal intestinal walls (P<2×10) and had T/M ratios of 1.19-2.72 with a mean of 1.85 and T/I ratios of 1.71-5.40 with a mean of 2.67. The individual SUVmax, SUVmean, T/M and T/I values were significantly higher in the entire tumour volume compared with the tumour volume adjusted for scatter from the urinary bladder (P<0.005), although the absolute differences were small.
  
  
  CONCLUSIONS
  F-FAZA PET/CT is feasible for visualization of hypoxia in patients with rectal cancer, but scattered activity from the urinary bladder should be taken into consideration.
authors.affiliation: Department of Oncology, Vejle Hospital, Kabbeltoft 25, 7100 Vejle, Denmark. birgitte.mayland.havelund@slb.regionsyddanmark.dk
authors.forename: Birgitte M
authors.initials: BM
authors.lastname: Havelund
authors.forename: Paw C
authors.initials: PC
authors.lastname: Holdgaard
authors.forename: Søren R
authors.initials: SR
authors.lastname: Rafaelsen
authors.forename: Lise S
authors.initials: LS
authors.lastname: Mortensen
authors.forename: Jørn
authors.initials: J
authors.lastname: Theil
authors.forename: Dirk
authors.initials: D
authors.lastname: Bender
authors.forename: John
authors.initials: J
authors.lastname: Pløen
authors.forename: Karen-Lise G
authors.initials: KL
authors.lastname: Spindler
authors.forename: Anders
authors.initials: A
authors.lastname: Jakobsen
mesh_terms: D000368:Aged; D001692:Biological Transport; D015687:Cell Hypoxia; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009367:Neoplasm Staging; D009593:Nitroimidazoles / Q000378:metabolism; D049268:Positron-Emission Tomography; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology*; D014057:Tomography, X-Ray Computed; D047368:Tumor Burden; D001743:Urinary Bladder / Q000000981:diagnostic imaging / Q000378:metabolism
chemical_list: D009593:Nitroimidazoles; C498052:fluoroazomycin arabinoside