Abstract: [Abstract]   Objective   To investigate the impact of PET-CT on the target volume delineation and precise radiothera?
py planning for patients with advanced non-small cell lung cancer (NSCLC).   Methods   PET-CT scanning was performed in 30 histologically proved NSCLC patients. The gross tumor volume (GTV) was delineated, and radiotherapy planning was established with identical parameters based on the CT image and PET-CT fused image, respectively. The differences of doses between GTV, planning target volume (PTV) and organsat rise (OAR) were compared.   Results   PET-CT image results changed the target volume delineation in 30 patients with 8 increased and 22 decreased. There were no differences in GTV and PTV between the VGTV and VPTV statistically, although PET-CT image changed conventional CT image size sketch of GTV and PTV. The V20 of total lung decreased in the PlanPET- CT compared with that of PlanCT (P < 0.05), but no differences were found in the V30 of total lung, mean lung dose (MLD), the data of spinal cord, esophagus and heart.   Conclusion   PET-CT may reduce the radiation injuries in the lung and improve the target dose.

Key words: positron- emission tomography, Carcinoma, Non-Small-Cell Lung, radiotherapy, radiotherapy dosage, PET-CT