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A 68-year-old man presented with right-side facial numbness. MRI showed an extra-axial mass infiltrating the right temporal bone. It was debulked surgically, and histopathology revealed metastatic adenocarcinoma. Ga PSMA PET/CT done in view of increased PSA levels and clinically suspicious hard lesion in prostate showed primary lesion in left side of prostate with metastases to the right temporal bone. Primary carcinoma of the prostate and metastases to the right temporal bone were proven histopathologically. Our case highlights the usefulness of Ga PSMA PET/CT in identifying the primary site in suspected prostate cancer and mapping the metastatic sites.

Ga-PSMA-HBED PET/CT showed promising results in staging and restaging of prostate cancer. However, nonspecific uptake has been reported in the celiac ganglia. In this case series, we showed faint radiotracer uptake on upper thoracic region in the location of cervicothoracic (stellate) ganglia. This ganglion is located anterior to the transverse process of C7 vertebra, inferior to subclavian artery, and superior to the neck of the first rib.

The potential applications of Ga-labeled prostate-specific membrane antigen (PSMA) PET/CT in the imaging of prostate cancer are now well established. A few case reports regarding the potential use of Ga-PSMA PET/CT in nonprostate cancer malignancies are also published. Apparently, the tumor neoangiogenesis is the mechanism attributed to increased Ga-PSMA uptake in the tumor sites in nonprostatic malignancies. We describe the use of Ga-PSMA PET/CT in imaging multiple myeloma. The intense Ga-PSMA avidity of the lesions also opens up the possibility of theranostics with Lu-PSMA.

Ga prostate-specific membrane antigen (PSMA) PET/CT is increasingly used to evaluate extent of disease in prostate carcinoma. We present a case of subacute cortical cerebral infarct showing focal uptake on PSMA PET/CT. It is an important potential cause of false-positive uptake in this imaging cohort. The patient is an 85-year-old man with a background of nonbacterial thrombotic endocarditis and previous cerebrovascular events. He was referred for PSMA PET/CT for staging of high-risk prostate cancer.

68Ga-PSMA ligand PET/CT for imaging prostate cancer is a novel imaging technique, which is rapidly gaining popularity. Sufficient evidence has been accumulated in literature regarding the usefulness of 68Ga-PSMA PET/CT in prostate cancer. Recently literature regarding the localization of 68Ga-PSMA PET/CT imaging in non-prostatic malignancies is also published, thus questioning the specificity of the tracer with regards to prostate cancer. This commentary tries to address the issue of specificity of 68Ga-PSMA PET/CT and its relevance in imaging prostate cancer.

WOS: 000392046200015, PubMed: 27666999

213 Background: For planning salvage procedures in recurrent prostate cancer accurate diagnostic tools are needed. Till now in patients suspicious for isolated local recurrent cancer invasive biopsy was needed. 68-Ga-PSMA-PET is frequently used to identify even small metastatic deposits. We analyzed the diagnostic value to identify local recurrence in patients after radiotherapy undergoing salvage radical prostatectomy, sRPE. Methods: We retrospectively reviewed patients undergoing sRPE with 68-Ga-PSMA-PET as preoperative staging. All patients underwent sRPE and extended lymph node dissection. Sensitivity, Specificity, pos and neg predictive value had been calculated per patient and per prostate lobe. Results: 37 patients with preoperative 68-Ga-PSMA-PEt could be identified. In all but one at least in one lobe PSMA staining could be identified. Mean tumor volume per prostate lobe was 6.22 (0.1-24)ml. Sensitivity, Specificity, neg and pos predictive value per lobe is 80%, 75%, 32% and 96%. Sensitivity to identify cancer recurrence per person irrespective of the side is 95% with a pos predictive value of 100%. Conclusions: 68-Ga-PSMA-PET seems to have a very high diagnistic value to identify local recurrence after radiotherapy. After validation of our experience an invasive biopsy to proof cancer recurrence might be spared.

We report on a case of biopsy-proven and MRI-staged rectal carcinoma with avid prostate-specific membrane antigen (prostate-specific membrane antigen) uptake on Ga PET/CT as part of the workup for synchronous prostate cancer. This case adds to the growing number of observational reports on the presence of significant nonprostatic prostate-specific membrane antigen activity in malignant tumors and highlights the need for careful interpretation of unsuspected sites.

Materials and methods A total of 322 patients with BRPC underwent either a PET-CT or a MR-PET examination (Siemens Biograph mMR) after injection of about 150 mBqGa-PSMA. Images were evaluated in cosensus by one experienced nuclear medicine physician and one radiologist. Pelvine lymphnode dissection was performed in most of the patients according to a predefined template with 8 fields. Lymphnode involvement was evaluated according to a 5 point scale with a patientand a field-based analysis. These findings were stratified according to PSA-values.

In prostate cancer with biochemical failure after therapy, current imaging techniques have a low detection rate at the prostate-specific antigen (PSA) levels at which targeted salvage therapy is effective. (11)C-choline and (18)F-fluoromethylcholine, though widely used, have poor sensitivity at low PSA levels. (68)Ga-PSMA (Glu-NH-CO-NH-Lys-(Ahx)-[(68)Ga-N,N'-bis[2-hydroxy-5-(carboxyethyl)benzyl]ethylenediamine-N,N'-diacetic acid]) has shown promising results in retrospective trials. Our aim was to prospectively compare the detection rates of (68)Ga-PSMA versus (18)F-fluoromethylcholine PET/CT in men who were initially managed with radical prostatectomy, radiation treatment, or both and were being considered for targeted therapy. METHODS: A sample of men with a rising PSA level after treatment, eligible for targeted treatment, was prospectively included. Patients on systemic treatment were excluded. (68)Ga-PSMA, (18)F-fluoromethylcholine PET/CT, and diagnostic CT were performed sequentially on all patients between January and April 2015, and the images were assessed by masked, experienced interpreters. The findings and their impact on management were documented, together with the results of histologic follow-up when feasible. RESULTS: In total, 38 patients were enrolled. Of these, 34 (89%) had undergone radical prostatectomy and 4 (11%) had undergone radiation treatment. Twelve (32%) had undergone salvage radiation treatment after primary radical prostatectomy. The mean PSA level was 1.74 ± 2.54 ng/mL. The scan results were positive in 26 patients (68%) and negative with both tracers in 12 patients (32%). Of the 26 positive scans, 14 (54%) were positive with (68)Ga-PSMA alone, 11 (42%) with both (18)F-fluoromethylcholine and (68)Ga-PSMA, and only 1 (4%) with (18)F-fluoromethylcholine alone. When PSA was below 0.5 ng/mL, the detection rate was 50% for (68)Ga-PSMA versus 12.5% for (18)F-fluoromethylcholine. When PSA was 0.5-2.0 ng/mL, the detection rate was 69% for (68)Ga-PSMA versus 31% for (18)F-fluoromethylcholine, and when PSA was above 2.0, the detection rate was 86% for (68)Ga-PSMA versus 57% for (18)F-fluoromethylcholine. On lesion-based analysis, (68)Ga-PSMA detected more lesions than (18)F-fluoromethylcholine (59 vs. 29, P < 0.001). The tumor-to-background ratio in positive scans was higher for (68)Ga-PSMA than for (18)F-fluoromethylcholine (28.6 for (68)Ga-PSMA vs. 9.4 for (18)F-fluoromethylcholine, P < 0.001). There was a 63% (24/38 patients) management impact, with 54% (13/24 patients) being due to (68)Ga-PSMA imaging alone. Histologic follow-up was available for 9 of 38 patients (24%), and 9 of 9 (68)Ga-PSMA-positive lesions were consistent with prostate cancer ((68)Ga-PSMA was true-positive). The lesion positive on (18)F-fluoromethylcholine imaging and negative on (68)Ga-PSMA imaging was shown at biopsy to be a false-positive (18)F-fluoromethylcholine finding ((68)Ga-PSMA was true-negative). CONCLUSION: In patients with biochemical failure and a low PSA level, (68)Ga-PSMA demonstrated a significantly higher detection rate than (18)F-fluoromethylcholine and a high overall impact on management.

[68Ga]PSMA-HBED-CC PET/CT to differentiate between diffuse bone metastases of prostate cancer and osteopoikilosis

79 Background: The implementation of 68Ga-PSMA-PET-imaging for staging and the impact on stage adaption during treatment radiotherapy (RT) planning is not well studied yet. The present work is to evaluate the integration of 68Ga-PSMA-PET into standard RT planning and to determine the influence on staging and on changes in the initially planned treatment concept for definitive RT in prostate cancer patients. Methods: A total of 66 prostate cancer patients with PSMA-PET delivered before treatment were retrospectively analyzed. All patients had bone scintigraphy and magnetic resonance imaging (MRI) of abdomen (52 patients; 79%) or thoraco-abdominal computed tomography (CT) (14 patients; 21%). After PSMA-imaging, all information was reviewed and re-classification was performed with the additional information taken into account. Thereafter, patients were evaluated with the information obtained by PSMA-PET imaging led to a change in staging and subsequently resulted in a change of the RT concept and treatment fields. Results: Median age of patients was 66 years (range 46 – 84 years). Median pretreatment PSA level was 25.2 ng/mL (range 4.4 – 130.8 ng/mL). The initial stage was changed in 27 patients (41%); 8 patients (12%) under-staged, 11 patients (17%) over-staged and 8 patents (12%) had distant metastasis. RT fields changed in 9 patients (14%) and RT cancelled because of distant metastasis detected with PSMA-PET in 6 patients (9%). The mean pretreatment PSA values were significantly higher in over-staged patients or patient with distant metastasis compared to under-staged patients (55.0±38.8 ng/mL vs. 28.1±19.1 ng/mL; p = 0.02). Also upstaging was observed more frequently in patients with ≥ T3a disease compared to patients with < T3 disease (15 patients [56%] vs. 4 patients [15%]; p = 0.04). However, Gleason score and primary tumor SUV had no significant impact on stage change and particularly on RT decision and treatment plan changes. Conclusions: The performance of a PSMA-PET frequently leads to changes in the stage, altering the RT treatment regimen especially in patients with extensive stage disease and higher pretreatment PSA values.

We describe the finding of a metastatic superscan detected by 68Ga-PSMA PET/CT imaging. A 63-year-old man with metastatic prostate carcinoma underwent 68Ga-PSMA PET/CT imaging for staging and evaluation of the most appropriate therapeutic option. Images demonstrated diffuse and extensive skeletal uptake in the axial and appendicular skeleton, corresponding to the typical red marrow distribution. Intense soft tissue uptake was also seen in the prostate and multiple pelvic and abdominal lymph nodes.

Ga-labelled PSMA ligandGlu-NH-CO-NH-Lys(Ahx)-HBED-CC.A 68-year-old patient was referred to our institution for radi-ation therapy planning and exclusion of distant metastases 4-months after biopsy-proven dia gnosis of left peripheral prostatecancer(PSA18.5ng/ml,Gleason score7).Whole-bodyPET/CT1 hour after injection of 171 MBq

e16110 Background: Patients with rising PSA levels after radical prostatectomy (RP) often present a diagnostic dilemma. A local recurrence or metastatic lymph node lesions would be amenable to addi...

Purpose: The purpose of our study was to evaluate the clinical impact of 68Ga-PSMA PET / CT in the setting of biochemical recurrence of prostate cancer. Materials and Methods: We retrospectively evaluated 125 prostate cancer patients submitted to the 68Ga-PSMA PET / CT due to biochemical recurrence. The parameters age, Gleason score, PSA levels, and the highest SUVmax were correlated to potential treatment changes. The highest SUVmax values were correlated with age and Gleason score. The median follow-up time was 24 months. Results: 68Ga-PSMA PET / CT led to a treatment change in 66 / 104 (63.4%) patients (twenty-one patients were lost to follow-up). There was a significant change of treatment plan in patients with a higher Gleason score (P = 0.0233), higher SUVmax (p = 0.0306) and higher PSA levels (P < 0.0001; median PSA = 2.55 ng / mL). Conclusion: 68Ga-PSMA PET / CT in prostate cancer patients with biochemical recurrence has a high impact in patient management.