Radiation Pneumonitis: Correlation of Toxicity With Pulmonary Metabolic Radiation Response

Abstract

Purpose-To characterize the relationship between radiation pneumonitis (RP) clinical symptoms and pulmonary metabolic activity on post-treatment [ 18 F]-fluorodeoxyglucose positron emission tomography (FDG PET).Methods-We retrospectively studied 101 esophageal cancer patients who underwent restaging FDG PET/CT imaging between 3 and 12 weeks after completing thoracic radiotherapy. The Common Toxicity Criteria version 3 (CTC3) was used to score RP clinical symptoms. Linear regression was applied to the FDG PET/CT images to determine the normalized FDG uptake versus radiation dose. The pulmonary metabolic radiation response (PMRR) was quantified as this slope. Modeling was performed to determine the interaction of PMRR, mean lung dose (MLD), and percentage of lung receiving greater than 20 Gy (V20) with RP outcomes.Results-Of the 101 patients, 25 had grade 0, 10 had grade 1, 60 had grade 2, 5 had grade 3, and 1 had grade 5 RP symptoms. Logistic regression demonstrated that increased values of both MLD and PMRR were associated with a higher probability of RP clinical symptoms (P=0.032 and P=0.033, respectively). Spearman's rank correlation found no association between the PMRR and dosimetric parameters (PTV, MLD, V5 through V30). Two-fold cross validation demonstrated the combination of MLD and PMRR was superior to either alone for assessing the development of Conflict of Interest Notification:The authors declare that they have no commercial or financial interests related to this study to disclose.Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Conclusions-This study demonstrated a significant correlation between RP clinical symptoms and the PMRR measured by FDG PET/CT following thoracic radiotherapy. NIH Public Access

Association Between Pulmonary Uptake of Fluorodeoxyglucose Detected by Positron Emission Tomography Scanning After Radiation Therapy for Non–Small-Cell Lung Cancer and Radiation Pneumonitis

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Anatomic, functional and molecular imaging in lung cancer precision radiation therapy: treatment response assessment and radiation therapy personalization

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