The combination of 13N-ammonia and 18F-FDG whole-body PET/CT on the same day for diagnosis of advanced prostate cancer.

PURPOSE - The aim of the study was to evaluate the efficacy of N-ammonia and F-fluorodeoxyglucose (F-FDG) PET performed on the same day in the detection of advanced prostate cancer (PC) and its metastases.

PATIENTS AND 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.

N-Ammonia and F-FDG PET/CT were performed on the same day (F-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 N-ammonia and F-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 N-ammonia for lymph node metastases were 77. 5 and 96. 3%, respectively, whereas the values were 75 and 44. 4% using F-FDG. The two modalities were highly correlated with respect to the detection of lymph nodes and bone metastases.

CONCLUSION - The concordance between the two imaging modalities suggests a clinical impact of N-ammonia PET/CT in advanced PC patients as well as of F-FDG. N-Ammonia is a useful PET tracer and a complement to F-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. This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4. 0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially. http://creativecommons. org/licenses/by-nc-nd/4. 0/.

Nuclear medicine communications. 2015 Nov 19 [Epub ahead of print]

Chang Yi, Donglan Yu, Xinchong Shi, Xiangsong Zhang, Ganhua Luo, Qiao He, Xuezhen Zhang

Departments of aNuclear Medicine bMedical Equipment, the First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.