The role of gamma-PET in the evaluation of patients with recurrent squamous cell cancer of the head and neck.

Squamous cell carcinoma (SCC) is the most common cancer of the head and neck (HNC). Advanced HNC warrants extensive ablative and reconstructive procedures, significantly altering locoregional anatomy, while radiation treatment further adds to the distortion. Anatomic imaging is therefore often inconclusive in suspected recurrent HNC. Functional imaging with fluorodeoxyglucose-positron emission tomography (FDG-PET) has been reported contributory in the evaluation of patients with SCC. While most reports are from dedicated PET systems, full ring PET is of limited availability and gamma-PET may offer a suitable compromise. The therapeutic impact of gamma-PET in patients with suspected recurrent HNC was retrospectively evaluated. Seventeen patients were evaluated. All had undergone surgery for HNC, 16 also received radiotherapy. gamma-PET scans were compared to anatomic imaging, histopathology and clinical follow-up. The impact of the FDG-PET scan on patient management was then evaluated. Eleven positive findings were confirmed. Two false positives were due to radiation changes, a recognized pitfall. There were no false negatives. Overall accuracy of the 18F-FDG gamma-PET scans was 88% with considerable effect on patient management. Gamma-PET with FDG appears valuable in the evaluation of suspected recurrent HNC, and may provide a suitable alternative when dedicated PET is unavailable.

The clinical impact of 18F-FDG gamma PET in patients with recurrent well differentiated thyroid carcinoma.

The therapeutic approach to recurrent well-differentiated thyroid cancer is based on the detection of active disease. While a measured increase of thyroglobulin level in an ablated patient is highly suggestive of recurrence, localization of the tumour is necessary for adequate treatment planning. A whole body scan with 131I yields false negative results in the presence of non-iodophyllic foci of disease. Hypermetabolic foci of differentiated thyroid carcinoma can be detected by gamma PET with 2-[18F]fluoro-2-deoxy-D-glucose (18F-FDG). This study retrospectively evaluated the therapeutic impact of the 18F-FDG scan in patients with suspected recurrent thyroid carcinoma in whom the iodine scan was negative. Twenty patients (five male, 15 female) aged 19-77 years, were suspected of having recurrent thyroid carcinoma due to elevated thyroglobulin levels and/or palpable neck findings. All whole body iodine scans obtained with diagnostic doses (74-148 MBq (2-4 mCi) of 131I), were reported normal, i.e., no iodophyllic foci were detected. Whole body gamma positron emission tomography (PET) imaging was performed in fasting patients following i.v. administration of 370 MBq (10 mCi) 18F-FDG, with a strict 1 h immobilization post-injection. Gamma PET results were validated either by anatomical imaging, repeat iodine scanning after administration of a therapeutic dose (at least 3,700 MBq (100 mCi) of 131I) or surgery. The impact of the FDG scan on patient management was evaluated by the referring physicians. Positive gamma PET results confirmed the presence of active disease in 14/15 patients. One false positive finding (fibrosis) and one false negative (carcinoid) were reported. Localization of hypermetabolic foci supported treatment decisions in 10 patients, and significantly altered therapeutic management in six others. Treatment was withheld in four patients with negative findings. The clinical impact of the scan in this patient group is similar to that reported in the literature and justifies its future implementation.

[Gastric evacuatory function in peptic ulcer studied using radionuclide research data]. / Izuchenie évakuatornoi funktsii zheludka pri iazvennoi bolezni po dannym radionuklidnogo issledovaniia.

The radionuclide method using labelled food was employed in 127 patients with gastric and duodenal ulcer to determine the gastric emptying function. The method is physiologic and safe. The character of disorders of gastric emptying rate was established in pyloroduodenal and mediogastric ulcers as well as the effect of gastric acid production on the rate of gastric emptying.