title: Variability of Gross Tumor Volume in Nasopharyngeal Carcinoma Using 11C-Choline and 18F-FDG PET/CT.
abstract: This study was conducted to evaluate the variability of gross tumor volume (GTV) using 11C-Choline and 18F-FDG PET/CT images for nasopharyngeal carcinomas boundary definition. Assessment consisted of inter-observer and inter-modality variation analysis. Four radiation oncologists were invited to manually contour GTV by using PET/CT fusion obtained from a cohort of 12 patients with nasopharyngeal carcinoma (NPC) and who underwent both 11C-Choline and 18F-FDG scans. Student's paired-sample t-test was performed for analyzing inter-observer and inter-modality variability. Semi-automatic segmentation methods, including thresholding and region growing, were also validated against the manual contouring of the two types of PET images. We observed no significant variation in the results obtained by different oncologists in terms of the same type of PET/CT volumes. Choline fusion volumes were significantly larger than the FDG volumes (p < 0.0001, mean ± SD = 18.21 ± 8.19). While significantly consistent results were obtained between the oncologists and the standard references in Choline volumes compared with those in FDG volumes (p = 0.0025). Simple semi-automatic delineation methods indicated that 11C-Choline PET images could provide better results than FDG volumes (p = 0.076, CI = [-0.29, 0.025]). 11C-Choline PET/CT may be more advantageous in GTV delineation for the radiotherapy of NPC than 18F-FDG. Phantom simulations and clinical trials should be conducted to prove the possible improvement of the treatment outcome.
authors.affiliation: School of Biomedical Engineering, Southern Medical University, Guangzhou, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Jiang
authors.affiliation: Department of PET Center, Nanfang Hospital, Guangzhou, China.
authors.forename: Hubing
authors.initials: H
authors.lastname: Wu
authors.affiliation: School of Biomedical Engineering, Southern Medical University, Guangzhou, China.
authors.forename: Meiyan
authors.initials: M
authors.lastname: Huang
authors.affiliation: School of Biomedical Engineering, Southern Medical University, Guangzhou, China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of PET Center, Nanfang Hospital, Guangzhou, China.
authors.forename: Quanshi
authors.initials: Q
authors.lastname: Wang
authors.affiliation: School of Biomedical Engineering, Southern Medical University, Guangzhou, China.
authors.forename: Jianqi
authors.initials: J
authors.lastname: Zhao
authors.affiliation: School of Biomedical Engineering, Southern Medical University, Guangzhou, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Yang
authors.affiliation: School of Biomedical Engineering, Southern Medical University, Guangzhou, China.
authors.forename: Wufan
authors.initials: W
authors.lastname: Chen
authors.affiliation: School of Biomedical Engineering, Southern Medical University, Guangzhou, China.
authors.forename: Qianjin
authors.initials: Q
authors.lastname: Feng
mesh_terms: D002250:Carbon Radioisotopes; D002277:Carcinoma; D002794:Choline; D019788:Fluorodeoxyglucose F18; D006801:Humans; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed; D047368:Tumor Burden
chemical_list: D002250:Carbon Radioisotopes; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D002794:Choline