Abstract：Objective To explore the differences between CT images and CT and nuclear magnetic resonance (MRI) images in the delineation of target areas of esophageal cancer.Methods Twenty-six patients with esophageal squamous cell carcinoma were enrolled between August 2017 and December 2018. Routine CT scan and diffusion-weighted imaging (DWI) were performed. The diffusion-sensitive gradient b value was 600 s/mm2. The esophagus was delineated on CT images and CT/MR DWI fusion images. Cancer GTV and PTV were delineated on these images before their lengths were calculated. The TiGRT treatment planning system was used to obtain the volumes of GTV and PTV, so that treatment plans were made on the two images at the same prescription dose and end-of-life restricted doses. The length, volume, prescription dose and dose difference related to GTV and PTV were compared between different plans. The paired sample t test was performed to calculate the P value.Results The planned dose distribution and parameters under both conditions met the clinical prescription dose requirements. The length and volume of PTV and GTV under the CT/MR DWI plan were smaller than those under the CT plan (P=0.00, 0.00, 0.01, 0.03). The mean dose of the lung in critical organs based on the DWI plan was significantly lower than on the CT plan (P=0.00).Conclusions The application of DWI in radiotherapy of esophageal cancer is more accurate and beneficial for the protection of normal tissues.
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2020, Vol. 31 
