18F-FDG-PET Imaging in Radiotherapy for Tumor Volume Delineation in Treatment of Head and Neck Cancer

Impact of primary tumor volume on local control after definitive radiotherapy for head and neck cancer

“…In an attempt to improve accuracy of primary tumor delineation, 18 F‐fluorodeoxyglucose ( 18 FDG) positron emission tomography (PET) has been incorporated in radiation treatment planning process. 18 FDG‐PET‐defined pTVs were consistently found to be significantly smaller compared with those based on pretreatment CT or MRI scans, but may offer the best approximation of the pTV as defined in the surgical specimen . Although the PET‐defined volume is highly dependent on the method of the PET signal segmentation tool, fusion of PET and CT information can improve intraobserver and interobserver variability .…”

18F-FDG-PET/CT-based treatment planning for definitive (chemo)radiotherapy in patients with head and neck squamous cell carcinoma improves regional control and survival

“…The significantly smaller volume (0.46 cc) of pre-existing lymph nodes in patients with FDG-PET/CT-based NTV suggests that borderline sized nodes carrying tumor deposits, but without pathological morphology, were identified by FDG-PET and added to the GTV. In the literature, several studies report nodal upstaging in 8-21% in patients with FDG-PET/CT-based NTV [11][12][13][14][15].…”

“…Because an increased glucose metabolism is characteristic of SCC, good accuracy of FDG-PET in the detection of nodal metastases was shown, and superiority of integrated FDG-PET/CT over conventional imaging was demonstrated [7][8][9][10]. In radiotherapy, defining the nodal target volume with FDG-PET/CT results in alteration of nodal treatment in approximately 1 out of 4 patients compared to conventional imaging; with nodal upstaging in 8-21% and down staging in 3-11% [11][12][13][14][15]. Increased FDG-accumulation in inflammatory cells, however, may cause false-positive nodal findings [7].…”

Evaluation of Hybrid PET/MRI for Gross Tumor Volume (GTV) Delineation in Liver Cancer Radiotherapy

“…We consider that this may be related to the imaging limitations of 18 F-FDG PET in liver cancer. Unlike in lung cancer patients, 18 F-FDG PET has already been established to play a role in the application of target volume contouring [21]. In addition, the artifacts caused by tumor location, anatomical boundaries, clinical situations, and patient cooperation during examination have a great impact on the quality of the contouring [22,23].…”