Rectal Carcinoma on 68Ga-PSMA PET/CT.

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.

Detection of synchronous gastric schwannoma on FDG PET/CT aided by discordant metabolic response.

This is a case of an unsuspected synchronous gastric schwannoma demonstrating increased F-FDG accumulation on PET/CT in a 65-year-old female patient diagnosed with non-Hodgkin lymphoma on the basis of different metabolic activity to other sites of disease at staging and discordant metabolic response to therapy. The gastric schwannoma was confirmed by histopathology and immunohistochemistry after surgical resection. This case adds to the limited literature on FDG-avid gastric schwannoma and highlights the importance of investigating differential metabolic activity and response on serial PET/CT imaging.

Potential for truncating the scan length of restaging FDG-PET/CT after chemoradiotherapy in head and neck squamous cell carcinoma.

BACKGROUND: Fluorine-18 fluorodeoxyglucose PET/computed tomography (CT) is now routinely used for staging and monitoring treatment response in head and neck squamous cell carcinoma (HNSCC). Although most patients with HSNCC have locoregional disease, distant metastases are relatively uncommon and occur predominantly in the lungs. AIM: To explore the potential of a limited scan range from the skull vertex to lung bases, viz. an 'above diaphragm' scan, as an adequate examination for assessment of disease following chemoradiotherapy. METHODS: A retrospective review of 240 patients with HNSCC both staged and monitored after therapy with (18)F-fluorodeoxyglucose PET/CT was conducted. Patients with previous HNSCC, unknown primary and known distant metastatic disease were excluded. Patients with positive PET/CT findings below the neck on the posttherapy study were confirmed on either follow-up clinical or radiological findings. RESULTS: A total of 196 (81.7%) patients had nodal disease at PET/CT staging. Unrelated findings were present in 50 (20.8%) patients, including five colonic neoplasms and two second malignancies. After an average of 6.4 months after staging, 13 patients (5.4%) demonstrated progression to distant metastases on the posttherapy PET/CT. All patients demonstrated intrapulmonary metastases. Two patients had additional liver metastases, which would not have impacted on the overall management. No patient demonstrated isolated disease below the diaphragm. CONCLUSION: A limited 'above-diaphragm' scan for early assessment following chemoradiotherapy may be safely considered. The benefits of this tailored approach flow onto both the health system and the patients as it can improve resource allocation by increasing scanner availability and patient throughput and reduces cumulative patient radiation exposure.