Objective To assess the role of 18F-FDG PET/CT in initial staging of head and neck squamous cell carcinoma and its impact on changing the management compared to other conventional methods. Patients and methods A prospective study of 31 patients (21 male and 10 female), mean age 49.3 ± 12.1 years with histologically confirmed squamous cell carcinoma of the head and neck (nasopharynx was the commonest cancer in 15 patients (48.4%), poorly differentiated grade represented 64.5% of all tumors. Initial staging was achieved according to routine physical examination, endoscopy, CT, U/S, MRI. Results The overall change in TNM staging by 18F-FDG PET/CT in relation to conventional methods was encountered in 15/31 patients (48.4%). PET/CT changed; T staging in three patients (9.6%), upstaging in two patients and downstaging in one patient. PET/CT upstaged all 13/31 patients in N staging (41.9%). 18F-FDG PET/CT changed; M staging in 3/31 (9.6%) patients, upstaging in two and downstaging in one patient. PET/CT results caused radiotherapy modification in 21/31 patients (67.7%). PET/CT detected intra-parotid nodule in four patients, so additional radiation was added to the parotid in the treatment field. Retropharyngeal nodes were detected by PET/CT in three patients that were missed by conventional imaging. 18F-FDG PET/CT detected two patients of thyroid papillary carcinoma and one case of sigmoid neoplasm confirmed by histopathology. Conclusion 18F-FDG-PET/CT is considered a valuable diagnostic test in head and neck squamous cell carcinoma at initial assessment which would change staging and radiotherapy planning and hence proper management.

Background: Despite the benefits of postoperative radiotherapy for gastric cancer patients after publishing the results of the Intergroup 0116 (INT-0116) study, there are still the concerns of radiation-induced toxicity. Aim: To determine the radiation technique that can eliminate the dose of radiation to the organ at risk (OAR) in patients postoperatively treated for gastric cancer with three-dimensional conformal radiotherapy (3D-CRT) or intensitymodulated radiotherapy (IMRT) using dosimetric analysis. Methods: A total of 22 computerized radiation plans were reviewed. Dosimetric values for 3DCRT and IMRT technique were calculated. The following dosimetric parameters were compared for the planned target volume (PTV); the homogeneity index, maximal and minimal doses, the volumes of PTV received 95 % and 107 % of the prescribed dose. In addition, the mean dose and dose volume histogram (DVH) for the OAR as, V20 for each kidney, V30 for the liver, maximum dose (Dmax) for D1% of the spinal cord and V40 to the heart . Results: The 3D-CRT and IMRT achieved comparable PTV coverage. However, IMRT was associated with a highly significant decrease in the mean V20 value of the right kidney by 15% (P=0.001) and left kidney by 9% (P=0.01). The IMRT significantly improved sparing of the mean irradiated volume and the V30 of the liver by 12% (P=0.01) and by 10% (P=0.02) respectively compared with 3D-CRT. On the other hand, the dosimetric parameters for the spinal cord and heart were comparable for the IMRT and 3D-CRT plans. Conclusion: In gastric cancer patients receiving postoperative radiotherapy, IMRT provided better protection for the liver and kidneys when compared to 3D-CRT.

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