title: The combination of 13N-ammonia and 18F-FDG whole-body PET/CT on the same day for diagnosis of advanced prostate cancer.
abstract: OBJECTIVE
  The aim of the study was to evaluate the efficacy of 13N-ammonia and 18F-fluorodeoxyglucose (18F-FDG) PET performed on the same day in the detection of advanced prostate cancer (PC) and its metastases.
  
  
  METHODS
  Twenty-six patients with high-risk PC [Gleason score 8-10 or prostate-specific antigen (PSA)> 20 ng/ml or clinical tumor extension ≥ T2c] were recruited into the study. 13N-Ammonia and 18F-FDG PET/CT were performed on the same day (18F-FDG followed ammonia, with an interval of a minimum of 2 h). Lesions were interpreted as positive, negative, or equivocal. Patient-based and field-based performance characteristics for both imaging techniques were reported.
  
  
  RESULTS
  There was significant correlation between 13N-ammonia and 18F-FDG PET/CT in the detection of primary PC (κ=0.425, P=0.001) and no significant difference in sensitivity (60.2 vs. 54.5%) and specificity (100 vs. 83.3%). The maximum standard uptake values and corresponding target-to-background ratio values of the concordantly positive lesions in prostate glands in the two studies did not differ significantly (P=0.124 and 0.075, respectively). The sensitivity and specificity of PET imaging using 13N-ammonia for lymph node metastases were 77.5 and 96.3%, respectively, whereas the values were 75 and 44.4% using 18F-FDG. The two modalities were highly correlated with respect to the detection of lymph nodes and bone metastases.
  
  
  CONCLUSIONS
  The concordance between the two imaging modalities suggests a clinical impact of 13N-ammonia PET/CT in advanced PC patients as well as of 18F-FDG. 13N-Ammonia is a useful PET tracer and a complement to 18F-FDG for detecting primary focus and distant metastases in PC. The combination of these two tracers on the same day can accurately detect advanced PC.
authors.affiliation: Departments of aNuclear Medicine bMedical Equipment, the First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.
authors.forename: Chang
authors.initials: C
authors.lastname: Yi
authors.forename: Donglan
authors.initials: D
authors.lastname: Yu
authors.forename: Xinchong
authors.initials: X
authors.lastname: Shi
authors.forename: Xiangsong
authors.initials: X
authors.lastname: Zhang
authors.forename: Ganhua
authors.initials: G
authors.lastname: Luo
authors.forename: Qiao
authors.initials: Q
authors.lastname: He
authors.forename: Xuezhen
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000641:Ammonia; D001859:Bone Neoplasms / Q000556:secondary; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009590:Nitrogen Radioisotopes; D049268:Positron-Emission Tomography; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology*; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D051598:Whole Body Imaging
chemical_list: D009590:Nitrogen Radioisotopes; D019788:Fluorodeoxyglucose F18; D000641:Ammonia