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Author Li, D. ♦ Chen, X. ♦ Li, X. ♦ Wu, H. ♦ Wang, J.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword APPLIED LIFE SCIENCES ♦ RADIATION PROTECTION AND DOSIMETRY ♦ ANIMAL TISSUES ♦ CHEMOTHERAPY ♦ COMPUTERIZED TOMOGRAPHY ♦ ENTROPY ♦ ESOPHAGUS ♦ IRRADIATION ♦ NEOPLASMS ♦ PATIENTS ♦ RADIATION DOSES ♦ RADIOTHERAPY ♦ SPINAL CORD
Abstract Purpose: To investigate the feasibility of assessing treatment response using CTs during delivery of radiation therapy (RT) for esophageal cancer. Methods: Daily CTs acquired using a CT-on-Rails during the routine CT-guided RT for 20 patients with stage II to IV esophageal cancers were analyzed. All patients were treated with combined chemotherapy and IMRT of 45–50 Gy in 25 fractions, and were followed up for two years. Contours of GTV, spinal cord, and non-specified tissue (NST) irradiated with low dose were generated on each daily CT. A series of CT-texture metrics including Hounsfield Unit (HU) histogram, mean HU, standard derivation (STD), entropy, and energy were obtained in these contours on each daily CT. The changes of these metrics and GTV volume during RT delivery were calculated and correlated with treatment outcome. Results: Changes in CT texture (e.g., HU histogram) in GTV and spinal cord (but not in NST) were observed during RT delivery and were consistently increased with radiation dose. For the 20 cases studied, the mean HU in GTV was reduced on average by 4.0HU from the first to the last fractions, while 8 patients (responders) had larger reductions in GTV mean HU (average 7.8 HU) with an average GTV reduction of 51% and had increased consistently in GTV STD and entropy with radiation dose. The rest of 12 patients (non-responders) had lower reductions in GTV mean HU (average 1.5HU) and almost no change in STD and entropy. For the 8 responders, 2 experienced complete response, 7 (88%) survived and 1 died. In contrast, for the 12 non-responders, 4 (33%) survived and 8 died. Conclusion: Radiation can induce changes in CT texture in tumor (e.g., mean HU) during the delivery of RT for esophageal cancer. If validated with more data, such changes may be used for early prediction of RT response for esophageal cancer.
ISSN 00942405
Educational Use Research
Learning Resource Type Article
Publisher Date 2016-06-15
Publisher Place United States
Journal Medical Physics
Volume Number 43
Issue Number 6


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