FIGURE 2. Example of software fusion of ¹⁸F-FDG PET and CT images of primary laryngeal carcinoma for IMRT field planning. Patient was scanned for both ¹⁸F-FDG PET and CT on flat bed, in personalized rigid radiotherapy mask covering head and shoulders to prevent positioning differences. Lymph node in neck that was only marginally enlarged on CT proved pathologic on ¹⁸F-FDG PET and was included in the radiotherapy field. (A) Transverse slice through pathologic lymph node. (B) Coronal slice. (C) Sagittal slice.