Abstract：Objective: To investigate the possibility and the methodology of integrating 11C-Choline PET/CT with 3D-CRT/IMRT treatment planning of brain tumors. Methods: Thirty-four consecutive patients presenting with various intracranial tumors before radiotherapy treatment were investigated. Volume delineation was performed on the CT data and PET/CT data separately. GTV and PTV calculated based on CT and PET/CT images were compared using SPSS software. Results: The GTV increased by 25% or more because of PET in 23.53% of cases. The GTV was reduced >25% in 44.12% of patients. Overall, in 67.65%(23/34) of cases, GTV delineation was changed significantly if information from metabolic imaging was used in the planning process. The modification of the GTV translated into altered PTV changes in 58.52%(20/34) of cases. In 3 cases, 11C-Choline PET/CT revealed distant metastasies, changing the treatment strategy from curative to palliative. In 5 cases, no solid evidence of tumor existence was found and their radiotherapy planning was canceled. Conclusion: Integrated 11C-Choline PET/CT for treatment planning for 3D-CRT improves the accuracy of volume delineation compared with that of CT alone. The impact on treatment outcome remains to be demonstrated.
2007, Vol. 18 
