Role of PET-CT in determining target volume for three-dimensional conformal radiotherapy of locally advanced pancreatic carcinoma / 第二军医大学学报

ABSTRACT

Objective: To investigate the value of positron emission tomography and computer tomography(PET-CT)in determining the target volume for three-dimensional conformal radiotherapy (3D-CRT) of locally advanced pancreatic carcinoma (LAPC), so as to lay a foundation for PET-CT-based precision radiotherapy. Methods: The target volume for 13 confirmed LAPC patients who were referred for radical radiation therapy were delineated on both CT imaging and PET-CT fused imaging. The gross tumor volume (GTV), clinical target volume (CTV), planned target volume (PTV), and received doses in the normal tissues were compared between the two images produced by the two methods. Results: PET-CT image altered GTV and PTV on CT images. For all the 13 patients, the GTVCT versus GTVPET-CT was (57.3±22.9)cm3 versus (68.4±31.7)cm3, CTVCT versus CTVPET-CT was (119.9±38.7)cm3 versus (132.7±47.5)cm3,and PTVCT versus PTVPET-CT was (288.6±52.1)cm3 versus (312.4±79.4)cm3, with significant difference found for all the three parameters (P<0.05). GTV of 6 patients was increased by more than 20%, with an average increase of 36.5%. PET-CT image changed the parameters of dose-volume histograms (DVH). When delivering the same target dose of 60 Gy in 30 fractions, received doses in the normal tissues were different for the two plans created by the two methods, but showing no statistical significance. Conclusion: PET-CT fused imaging can accurately delineate the target volume for 3D-CRT of LAPC while keeping the received doses in the normal tissues within clinically acceptable level, which can help to create better 3D-CRT, but further conclusion still needs larger sample studies.