The Value of 99mTc-PSMA SPECT/CT-Guided Surgery for Identifying and Locating Lymph Node Metastasis in Prostate Cancer Patients.

BACKGROUND: This study evaluated the effect of technetium-99m (99mTc)-labeled prostate-specific membrane antigen (PSMA)-based image-guided surgery on the oncologic outcomes for patients with primary or recurrent prostate cancer (PCa). METHODS: This study retrospectively analyzed 54 consecutive patients with PCa who underwent 99mTc-labeled PSMA-based image-guided surgery between January 2016 and September 2017. These patients received a radical prostatectomy (RP) with pelvic lymph node dissection (PLND) or salvage lymph node dissection (sLND). The resected specimens were compared with findings of postoperative histologic analysis. The responses to the treatment were recorded during the follow-up period. RESULTS: In 31 patients, PSMA single-photon emission computerized tomography (SPECT) and computed tomography (CT) could find 52 suspicious lymph node metastases (LNMs). With the help of PSMA SPECT/CT, 12 patients with recurrence received sLND, 19 primary PCa patients received RP with extended PLND, and 23 primary PCa patients received RP with standard PLND. The findings showed that PSMA SPECT/CT could detect LNMs with high sensitivity and specificity. In six patients, PSMA SPECT/CT could find more LNMs that were not found by MRI and help to modify the extent of lymphadenectomy. At the latest follow-up evaluation, 39 patients showed a biochemical response (BR), 9 patients showed a biochemical recurrence (BCR) after BR, and 6 patients never exhibited BR. The patients who received RP with standard PLND or extended PLND had a better prostate-specific antigen (PSA) response than the patients who received sLND. The patients with pelvic LNMs also had a better PSA response than the patients with retroperitoneal LNMs. CONCLUSIONS: This study showed that 99mTc-PSMA SPECT/CT-guided surgery can remove more LNMs than conventional imaging with high sensitivity and specificity and delay disease progression in PCa patients.

Evaluation of 99mTc-labeled PSMA-SPECT/CT imaging in prostate cancer patients who have undergone biochemical relapse.

Using conventional imaging modalities, it is difficult to detect recurrent lesions in prostate cancer patients who have undergone biochemical relapse, especially in patients with low prostate-specific antigen (PSA) levels. We retrospectively reviewed the files of fifty patients with histopathologically confirmed prostate cancer who underwent 99mTc-labeled prostate-specific membrane antigen (PSMA) single-photon emission computed tomography (SPECT)/computed tomography (CT), magnetic resonance imaging (MRI), and bone scan within a 30-day period. PSMA-SPECT/CT indicated metastatic lesions in 39 patients and had a higher detection rate (78.0%) than bone scan (34.0%) or MRI (40.0%). The diagnostic efficiency of PSMA-SPECT/CT imaging for bone and lymph node metastases (50.0% and 42.0%) was better than bone scan (34.0% and 0.0%) or MRI (24.0% and 20.0%). PSMA-SPECT/CT provided a higher detection rate at serum PSA levels of ≤1 ng ml-1, 1-4 ng ml-1, 4-10 ng ml-1, and >10 ng ml-1. No correlation was found between Gleason score, PSA level, and the tracer tumor/background ratio of metastatic lesions. With the aid of PSMA-SPECT/CT imaging, the therapeutic strategy was changed for 31 patients, and this may have enhanced their clinical outcome. In conclusion, PSMA-SPECT/CT imaging could detect more metastatic lesions and achieve a higher detection rate than conventional imaging modalities at different serum PSA levels in prostate cancer patients who had undergone biochemical relapse.

Role of SUV(max) obtained by 18F-FDG PET/CT in patients with a solitary pancreatic lesion: predicting malignant potential and proliferation.

OBJECTIVES: Maximum standardized uptake value (SUV(max)) is a marker of tumor glucose metabolism detected by [(18)F]-fluorodeoxyglucose ((18)F-FDG) PET/computed tomography (PET/CT) and reflects tumor aggressiveness. The aim of the study was to evaluate the value of SUV(max) in differentiating benign from malignant solitary pancreatic lesions and explore the correlation between SUV(max) and tumor proliferative activity. MATERIALS AND METHODS: F-FDG PET/CT scans were performed in 80 patients with solitary pancreatic lesions who were scheduled for resective surgery. The relationships between SUV(max) and postoperative pathologic diagnosis, histologic grade, and Ki-67 proliferation index (PI) were analyzed. RESULTS: Of these 80 patients, 54 had malignant lesions. The SUV(max) of malignant tumors (6.3 ± 2.4) was significantly greater than that of benign lesions (2.9 ± 2.0) (P<0.001). Receiver-operating characteristic curve analysis showed that the SUV(max) cutoff value of 3.5 had a high sensitivity (92.6%) and specificity (76.9%) for the diagnosis of malignancies. Among pancreatic cancers with low (Ki-67<5%), moderate (5% ≤ Ki-67<50%), and high (Ki-67 ≥ 50%) PI, SUV(max) increased significantly from 4.2 ± 1.2, through 6.0 ± 1.7, to 8.6 ± 2.5 (P<0.001). The SUV(max) had a positive correlation with Ki-67 PI (P<0.001, r=0.60). CONCLUSION: The SUV(max) of F-FDG PET/CT can be used in the differential diagnosis of solitary pancreatic lesions and can also aid in the prediction of proliferative activity of pancreatic cancer.

Calcified metastases from ovarian carcinoma highlighted by F-18 FDG PET/CT: report of two cases.

Two cases of postoperative female patients with ovarian serous papillary carcinoma were referred for F-18 Fluorodeoxyglucose (F-18 FDG) PET/CT to evaluate suspicious recurrence and/or metastasis. One patient presented with multiple extensive calcified lesions with increased FDG uptake in the abdominopelvic cavity and the series of PET/CT scans showed progression of disease after chemotherapy. The other patient presented with three calcified masses with intensive uptake of FDG located in the left pelvis, the right subphrenic region, and the right supradiaphragmatic area, respectively. These suggest that F-18 FDG PET/CT can be useful in identifying malignant calcification and assessing therapeutic response of calcified malignancy.

The clinical value of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography in postoperative patients with gastrointestinal mucinous adenocarcinoma.

OBJECTIVE: To evaluate the clinical value of F-fluorodeoxyglucose positron emission tomography and computed tomography (¹8F-FDG PET/CT) in postoperative patients with gastrointestinal mucinous adenocarcinoma. METHODS: From July 2007 to March 2009, 30 patients who had previous surgical resection of histopathologically diagnosed gastrointestinal mucinous adenocarcinoma underwent ¹8F-FDG PET/CT scans in our center. The standard of reference for tumor recurrence, regional lymph node (LN) metastasis, peritoneal and distant metastasis consisted of histopathologic confirmation or clinical follow-up information for at least 6 months after PET/CT examinations. RESULTS: With final diagnosis, tumor recurrences were confirmed in eight of the 30 patients (26.7%). If a maximum standardized uptake value (SUVmax) of 2.5 or more was used as a cut-off point, the sensitivity, specificity, and accuracy of PET/CT were 87.5, 77.3, and 80.0%, respectively. However, if an SUVmax of 4.0 or more was the criterion, the sensitivity, specificity, and accuracy were 25.0, 86.4, and 70.0%, respectively. A cut-off point of 2.5 showed a higher sensitivity (P=0.041), and there was no statistical difference in the specificity and the accuracy of these two criteria. For the diagnosis of metastasis in regional LNs and peritoneum, the detection rate was 95.2 and 86.4%, respectively. In addition, we followed up 20 patients with 26 suspicious distant lesions. The sensitivity, specificity, and accuracy were 58.3, 92.9, and 76.9%, respectively. CONCLUSION: ¹8F-FDG PET/CT may be effective to discriminate tumor recurrence, and to detect regional LNs, peritoneal and distant metastasis in postoperative patients with gastrointestinal mucinous adenocarcinoma.

Tissue-targeting lead generation and optimization from random and directed screening of technetium-99m labeled tripeptide complex libraries in vivo.

BACKGROUND: Screening libraries against a molecular target in vitro are idealized models that cannot reflect the real state in vivo where biomolecules coexist and interact. C-terminal amide tripeptides labelled with Technetium-99m can provide a unique noninvasive approach to trace a large number of compounds in vivo. METHODS: The C-terminal amide tripeptide libraries were synthesized on Rink Amide-MBHA resin using iterative and pooling protocol. Technetium (V) oxo core [TcO(3+)] was bound to each tripeptide via 4 deprotonated nitrogen atoms to form a library of 8000 (99m)Tc tripeptoid complexes. The radiocombinatorial screening (RCS) in vivo was carried out on SD rats and A549 tumour bearing mice. RESULTS: Signals of tissue distribution and metabolism of libraries were recorded by counting or imaging and tissue targeting leads identified by both random and directed RCS. Among them, (99m)Tc RPA, (99m)Tc VIG and (99m)Tc RES had specific tissue targeting in kidney, liver and tumour respectively. The percent injected dose per gram tissue of (99m)Tc labelled leads in their target tissue was highly structure dependent. Because the nontarget tissue binding and the metabolism of (99m)Tc tripeptoid sublibraries were simultaneously monitored successfully by RCS, the interference of background activity was limited to the lowest level. Optimization of renal function agent from the labelled libraries was carried out by directed screening. (99m)Tc DSG was finally identified the most promising agent for renal function studies. CONCLUSIONS: RCS in vivo is a powerful tool for the discovery of tissue targeting drugs. The potential screening bias is probably the major limitation of labelled libraries.