Author/Authors :
chen، yangchun نويسنده Department of Nuclear Medicine, Quanzhou First Hospital, Fujian Medical University, Quanzhou, China , , Chen، Xiangrong نويسنده Department of Radiology, Quanzhou First Hospital, Fujian Medical University, Quanzhou, China , , Liu، Ji-an نويسنده Guangdong Provincial Key Laboratory of Micro-nano Manufacturing Technology and Equipment, Guangdong University of Technology, Guangzhou, China , , Li، Fanyong نويسنده The PET-CT Center, First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China ,
Abstract :
Objective(s): Considering the fact that the standardized uptake value (SUV) of a normal lung tissue is expressed as x±SD, x+3×SD could be considered as the threshold value to outline the internal tumor volume (ITV) of a lung neoplasm.
Methods: Three hollow models were filled with 55.0 kBq/mL fluorine18- fluorodeoxyglucose (18F-FDG) to represent tumors. The models were fixed to a barrel filled with 5.9 kBq/mL 18F-FDG to characterize normal lung tissues as a phantom. The PET/CT images of the phantom were acquired at rest. Then, the barrel was moved periodically to simulate breathing while acquiring PET/CT data. Volume recovery coefficient (VRC) was applied to evaluate the accuracy of ITVs. For statistical analysis, paired t-test and analysis of variance were applied.
Results: The VRCs ranged from 0.74 to 0.98 and significantly varied among gross tumor volumes for delineating ITV (P < 0.01). In two-dimensional PET scans, the motion distance did not affect VRC (P > 0.05), whereas VRC decreased with increasing distance in three-dimensional PET scans (P < 0.05).
Conclusion: The threshold value (x+3×SD) had the potential to delineate the ITV of cancerous tissues, surrounded by lung tissues, particularly in two-dimensional PET images.
