Positron-emission tomography/computed tomography (PET/CT) in the head and neck region is susceptible to artifacts caused by dental restorations. Metal artifact reduction is an established technology that can be used to improve the quality of CT images. The diagnostic efficacy of single-energy metal artifact reduction (SEMAR) for head and neck cancer has not been proven. We aimed to investigate the efficacy of SEMAR with PET/CT in the field of head and neck cancer. The study included 46 patients who underwent PET/CT with SEMAR. For qualitative evaluation, images with and without SEMAR were visually evaluated by two radiologists using a 5-point scale. For quantitative assessment, the standardized uptake values (SUVs) -related parameters were assessed based on their position in normal structures such as the tongue, tonsils, masseter muscles, and spinal cord. The qualitative analysis revealed that SEMAR improved the overall quality of PET/CT fusion images (2.28 ± 1.24 points vs. 3.61 ± 0.77 points, p < 0.0001). The scores for normal structures were also enhanced. SEMAR did not change the SUV-related values significantly. In conclusion, SEMAR significantly improved the quality of PET/CT fusion images. Thus, SEMAR with PET/CT clearly has potential diagnostic efficacy.

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Background and Aim: The aim of the present study was to evaluate the clinical usefulness of the ¹³C breath test in postoperative patients who underwent gastric tube reconstruction following esophagectomy. Methods: Postoperative patients (POs; n=26) and healthy volunteers (HVs; n=10) were included as subjects. Of the 26 POs, the 7 with late dumping symptoms were regarded as the dumping group (DG), and the remaining were considered the non-dumping group (NDG). Semisolid test meal mixed with 100 mg of ¹³C-sodium acetate was given to each subject. Breath samples for the ¹³C gas analysis and blood samples were collected. Results: The Cmax was 37 ± 13(‰) in the HVs and 49 ± 11(‰) in POs, being significantly higher in POs (p=0.019). The Cmax was 56 ± 14(‰) for DG and 47 ± 8.9(‰) for NDG, indicating that the Cmax in the DG tended to be higher than that in the NDG, although not to a significant degree (p=0.12). The change in the C value and each glucose metabolism-related marker showed a general correlation. Conclusion: The present results suggest that the ¹³C-acetate breath test reflects changes in glucose homeostasis after esophagectomy, making it useful for objectively and simply assessing late dumping symptoms in postoperative esophageal cancer patients.

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