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Purpose: To evaluate 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) single photon emission computed tomography (SPECT) in the detection of clinically occult primary tumors of the upper aerodigestive tract., Materials and Methods: Eighteen patients with histologically proved cervical nodal metastasis from squamous cell carcinoma (SCC) underwent FDG SPECT; 17 also underwent computed tomography (CT) and one underwent magnetic resonance (MR) imaging. All 18 patients underwent direct panendoscopy and biopsy. Biopsy and imaging results were correlated., Results: Among 11 histologically proved primary tumors, FDG SPECT depicted nine tumors; CT depicted four lesions. Five patients had abnormal FDG uptake with negative biopsy results. Among five patients with normal SPECT findings, biopsy results were positive in two and negative in three. FDG SPECT at the initial reading had sensitivity of 81%, specificity of 38%, positive predictive value of 64%, and negative predictive value of 60% for detection of occult primary tumors., Conclusion: FDG SPECT guidance of endoscopic biopsies in patients with occult primary SCCs of the head and neck has the potential to yield a higher rate of positive biopsy results than that traditionally expected from "blind" endoscopic procedures with "random" or "speculative" biopsy. FDG SPECT and CT are likely to remain complementary studies for the detection of occult primary tumors of the head and neck.

Purpose: To compare the uptake of 2-[F-18] fluoro-2-deoxy-D-glucose (fludeoxyglucose F-18; F-18 FDG) and thallous chloride Tl 201, using single-photon emission CT (SPECT), for the detection and location of squamous cell carcinoma of the head and neck., Methods: Five patients with biopsy-proved squamous cell carcinoma of the upper aerodigestive tract underwent both F-18 FDG and thallium-201 SPECT on the same day. F-18 FDG SPECT was performed using a dual-head gamma camera equipped with commercially available, extremely high-energy collimators (full width half-maximal height, 17 mm for 511 keV photons). Tumor size was estimated at 1.0 to 5.0 cm3 in these cases., Results: F-18 FDG SPECT showed five of five primary tumors. In two of the five cases, normal salivary gland activity severely limited thallium SPECT, and the tumors could not be definitively identified. Two of four lymph node groups that were positive for metastatic disease by CT criteria were shown by F-18 FDG SPECT. None were seen with thallium imaging. In one case, F-18 FDG SPECT was able to show a tumor that was not visible on CT., Conclusions: F-18 FDG has advantages over Tl-201 as a squamous cell carcinoma imaging agent (primarily because of its reduced salivary activity). F-18 FDG SPECT has potential as a viable, less expensive alternative to F-18 FDG positron emission tomography. The ultimate value of F-18 FDG SPECT imaging for detecting occult malignancy, monitoring therapeutic effectiveness, or evaluating tumor recurrence remains to be determined in patients with squamous cell carcinoma of the head and neck.

Purpose: At the time of the co-development of a commercial dual-headed gamma camera for whole-body single photon emission computed tomography (SPECT), modifications were made to permit imaging of 511-keV photons (from positron emitters) while maintaining versatility and cost-effectiveness in nuclear medicine for routine nonpositron studies., Materials and Methods: Special collimators were made, and gantry stability was increased. Detector shielding and crystal thickness were not changed. In phantoms, healthy volunteers (two men, aged 34 and 38 years), and 109 patients (71 male and 38 female patients, aged 2-74 years [mean, 56 years]), SPECT was performed with 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG). In patients, 36 myocardial viability, 47 oncologic, and 26 brain examinations were performed., Results: All FDG SPECT scans were subjectively judged to be of acceptable quality. Preliminary results in regard to diagnostic findings are reviewed; this analysis is intended to be a feasibility study not a conclusive review of imaging accuracy., Conclusion: FDG SPECT provides images that are interpretable for cardiac or oncologic diagnosis, without the need for or expense of a positron emission tomography (PET) center or a dedicated PET scanner.