51. Impact of intravenous contrast used in computed tomography on radiation dose to carotid arteries and thyroid in intensity-modulated radiation therapy planning for nasopharyngeal carcinoma.
- Author
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Lee VHF, Ng SCY, Kwong DLW, Lam KO, and Leung TW
- Subjects
- Adult, Aged, Aged, 80 and over, Artifacts, Carotid Arteries diagnostic imaging, Female, Humans, Male, Middle Aged, Nasopharyngeal Neoplasms diagnostic imaging, Radiotherapy Dosage, Radiotherapy, Image-Guided methods, Reproducibility of Results, Sensitivity and Specificity, Thyroid Gland diagnostic imaging, Carotid Arteries drug effects, Nasopharyngeal Neoplasms radiotherapy, Radiation Exposure analysis, Radiotherapy Planning, Computer-Assisted methods, Radiotherapy, Intensity-Modulated methods, Thyroid Gland drug effects, Tomography, X-Ray Computed methods
- Abstract
The aim of this study was to investigate if intravenous contrast injection affected the radiation doses to carotid arteries and thyroid during intensity-modulated radiation therapy (IMRT) planning for nasopharyngeal carcinoma (NPC). Thirty consecutive patients with NPC underwent plain computed tomography (CT) followed by repeated scanning after contrast injection. Carotid arteries (common, external, internal), thyroid, target volumes, and other organs-at-risk (OARs), as well as IMRT planning, were based on contrast-enhanced CT (CE-CT) images. All these structures and the IMRT plans were then copied and transferred to the non-contrast-enhanced CT (NCE-CT) images, and dose calculation without optimization was performed again. The radiation doses to the carotid arteries and the thyroid based on CE-CT and NCE-CT were then compared. Based on CE-CT, no statistical differences, despite minute numeric decreases, were noted in all dosimetric parameters (minimum, maximum, mean, median, D05, and D01) of the target volumes, the OARs, the carotid arteries, and the thyroid compared with NCE-CT. Our results suggested that compared with NCE-CT planning, CE-CT scanning should be performed during IMRT for better target and OAR delineation, without discernible change in radiation doses., (Copyright © 2017 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.)
- Published
- 2017
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