Background and purpose: Prostate-specific membrane antigen (PSMA)

a cell surface protein with high expression in prostate carcinoma (PC) cells

is an attractive target for PC imaging and therapy. Small-molecule radiopharmaceuticals targeting PSMA can detect the loc

ation and extent of disease with high sensitivity and specificity. The aim of this study was to evaluate the value of technetium-99m-labelled small molecule against PSMA (HYNICGlu- Urea-A

99m

Tc-PSMA) for the detection of primary and metastatic prostate cancers. Methods: Twenty-four prostate cancer patients and 1 patient with benign prostate hyperplasia received whole-body scan followed by abdominopelvic SPECT/CT 2 h after intravenous injection of

99m

Tc-PSMA. Tumor to muscle uptake ratio of

99m

Tc-PSMA was calculated using region of interest (ROI) technology. The sensitivity and specificity of

99m

Tc-PSMA were evaluated. The relationships between positive

99m

Tc-PSMA and prostate specific antigen (PSA) level and Gleason Score were analyzed. Results: Based on per patient

the sensitivity and specificity of

99m

Tc-PSMA were 72.7% (16/22) and 100% (3/3)

respectively. The level of PSA in patients with positive

99m

Tc-PSMA imaging was significantly higher than that in patients with negative

99m

Tc-PSMA imaging [(PSA median 17.31 ng/mL

range: 2.26-3 239.0 ng/mL) vs (PSA median 0.49 ng/ mL

range: 0.07-9.28 ng/mL)

]

(Z=-3.51

P0.001). Among newly diagnosed patients and recurrent patients with PSA more than 2.0 nm/mL

it was apparent that

99m

Tc-PSMA imaging was able to detect lesions with improved sensitivity of 94.1% (16/17). Gleason Scores between positive

99m

Tc-PSMA patients and negative

99m

Tc-PSMA patients were not significantly different (Z=-0.69

P=0.52). Conclusion: With the combination of whole-body scan and tomography

99m

Tc-PSMA SPECT/CT can be an excellent and specific molecular imaging strategy to detect prostate cancer and its metastases.