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PurposeTo prevent hemorrhagic complications, hemostatic agents (HAs) have been widely used in recent years. The use of HAs can lead to false-positive results on postoperative imaging. There exists only 1 study in the literature evaluating these applications during surgical procedures. Therefore, we aimed to evaluate the postoperative imaging features of polysaccharide-based HAs in thoracic surgery patients who have had 18F-FDG PET/CT scans.Patients and MethodsTwo hundred nine consecutive patients who underwent thoracic surgery were enrolled in this study. A topical polysaccharide-based HA was applied to the surgical bed for all of the patients. The patients diagnosed with cancer were followed up with subsequent thoracic CT scans, and 42 of these patients were also imaged with 18F-FDG PET/CT, which then comprised the main study group. Due to suspicion of metastasis, 19/42 patients were reoperated or rebiopsied. The latest histopathological findings were accepted as criterion standard, and previous FDG PET/CT images were retrospectively reevaluated.ResultsPolysaccharide-based HAs that appear as amorphous basophilic material were identified in histopathological samples of 11/19 patients. Lymphocytes, plasma cells, and histiocytes, which formed foreign body reaction and/or foreign body granuloma, indicating the presence of chronic inflammation, were seen in all of the samples. 18F-FDG PET/CT showed increased FDG uptake in all of these lesions.ConclusionsDespite the inconsistency of the literature, polysaccharide-based HAs can be demonstrated in human surgical specimens as amorphous basophilic materials even after a long time from the initial surgical procedure. These agents almost always cause chronic inflammatory changes. In addition, these agents may mimic “false-positive” findings on postoperative FDG PET/CT scans.

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This paper presents a comparative evaluation of wide-bandgap power semiconductor devices for domestic induction heating application, which is currently a serious alternative to traditional heating techniques. In the induction heating system, the power transferred to the output depends on the equivalent resistance of the load, and the resistance depends on the operating frequency. Due to the switching characteristics of wide-bandgap power semiconductor devices, an induction heating system can be operated at higher operating frequencies. In this study, SiC and Si semiconductor devices are used in the comparison. These devices are compared according to different evaluation issues such as the turn-off energy losses, turn-off times, current fall time, the power losses of the internal diodes, and the conduction voltage drops issues. To perform the proposed evaluation, the series-resonant half-bridge inverter, which is frequently used in state-of-the-art induction heating systems, has been selected. The device suitability in an induction heating system is analyzed with the help of a test circuit. A comparison is made in terms of criteria determined by using the selected switches in the experimental circuit, which is operated in the 200 W to 1800 W power range and 45 kHz to 125 kHz switching frequency range. System efficiency is measured as 97.3% when Si IGBT is used. In the case of using SiC cascode JFET, the efficiency of the system is increased up to 99%.

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