Cancer Management and Research (Jul 2021)
Evaluation of Hybrid PET/MRI for Gross Tumor Volume (GTV) Delineation in Colorectal Cancer Liver Metastases Radiotherapy
Abstract
Yan-Nan Zhang,1,* Xin Lu,1,* Zhen-Guo Lu,1 Li-Ping Fu,1 Jun Zhao,2 Zuo-Lin Xiang1 1Department of Radiation Oncology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, People’s Republic of China; 2Department of Nuclear Medicine, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, People’s Republic of China*These authors contributed equally to this workCorrespondence: Zuo-Lin XiangDepartment of Radiation Oncology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, People’s Republic of ChinaTel +86 021-38804518-15341Email [email protected]: Hybrid PET/MRI has been increasingly incorporated into the practice of radiation oncologists since it contains both anatomical and biological data and may bring about personalized radiation plans for each patient. The objective of this study was to evaluate the feasibility of GTV delineation from hybrid PET/MRI compared with that from current-practice MRI during radiotherapy planning in patients with colorectal liver metastases.Patients and Methods: Twenty-four patients (thirty lesions) with colorectal liver metastases were prospectively enrolled in this study. Three physicians delineated the target volume with the most popular delineating methods—the visual method. First of all, differences among the three observers were assessed. The difference and correlation of GTV values obtained by MRI, PET, and hybrid PET/MRI were subjected to statistical analysis afterwards. Finally, the dice similarity coefficient (DSC) was calculated to assess the spatial overlap. Based on the value of DSC, we also evaluate the correlation between DSC and tumor size. GTV-MRI was set as a reference.Results: There was no significant difference among observers in GTV-MRI (F= 0.118, p= 0.889), GTV-PET (F= 0.070, p= 0.933) and GTV-PET/MRI (F= 0.40, p= 0.961). 83.33% of GTV-PET/MRI and 63.33% of GTV-PET were larger than the reference GTV-MRI. Statistical analysis revealed that GTV-PET/MRI (p
