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This 65 year-old woman, 1 month postoperative after maxillary sinus carcinoma (pT4N0cM0) excision and reconstruction, presented with significant left facial clear fluid wound leakage. A salivary or cerebrospinal leakage was suspected. Fluid analysis, CT, and MRI were noncontributory. Dynamic salivary scintigraphy with SPECT-CT allowed for the detection and localization of the leakage from the left parotid gland. Radioactive dose rate of the wound bandage was 50 μSv/h compared with 0.05 μSv/h for background and confirmed the diagnosis. Left total parotidectomy resulted in resolution.

This study presents quality controls and segmentation tools for gated acquisition imaging of moving tumors. We study the effect of different amplitudes in a bin in function of sizes of spheres and signal to background ratios. Simple rules are then derived to establish which bins are appropriate to quantify tumor activity and to delineate volume. Finally the threshold technics for gated acquisition exams are discussed in function of the different parameters. Our experimental setup consisted of a movable platform, a thorax phantom with 6 fillable spheres and a real time position management device allowing to synchronize the PET/CT image with movement. The spheres were filled with F-Fluoro-2-deoxy-glucose and the activity in the tank was adjusted to obtain signal to background ratios from 3.5 to 20 (228 combinations of experimental parameters were studied). Maximal activity, optimal threshold and elongation of the sphere images between static and moving tumors were then compared with our own matlab program. Significant changes had appearing for movement superior to 7.5 mm in a bin leading to an activity decrease, an increase of the optimal threshold and an elongation in the movement direction. These effects were accentuated for low SBR and a sphere diameter inferior to 20 mm. The optimal threshold value was around 35% for large spheres and high SBR. This value increase when the sphere size and the SBR decrease. We then deduce from our measurements the relevant parameters for the delineation procedure. In conclusion, the effect of movement were successfully quantified in function of the sphere size, SBR and movement in a bin. Calibration threshold curves are now available in a clinical routine used for gated acquisitions.