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Can Dual-Energy CT Help in Rectal Cancer Treatment Planning

C Ma

C Ma1*, Y Dong1 , Y Zhang2 , J Liu1 , T Lin1 , J Fan1 , R Price1 , L Chen1 , (1) Fox Chase Cancer Center, Philadelphia, PA, (2) Tongdu Hospital, Xian, China


TU-L-GePD-J(B)-2 (Tuesday, August 1, 2017) 1:15 PM - 1:45 PM Room: Joint Imaging-Therapy ePoster Lounge - B

Purpose: Our previous study has demonstrated that dual energy CT provided advantageous features in head and neck target delineation. At lower monoenergies images, the contrast of brain metastases was comparable to T1-weighted MR imaging with contrast agent. The purpose of this study is to investigate the clinical application of dual energy CT for treatment planning of rectal cancer.

Methods: Three rectal cancer patients were included in this study. Each patient was scanned using the Siemens SOMATOM Definition AS (Open 20RT). The CT scanner allowed for sequential acquisition of two image datasets at 80kVp and 140kVp with the same acquisition time and radiation dose as a single energy scan. Images were reconstructed for nominal monoenergies between 40keV and 190keV, and a mixed energy of 120kVp, which is equivalent to that currently used in routine clinical practice. The reconstructed images were compared using the Varian VelocityAI software. During the comparison of those images, attention was focused on any differences in the bone and soft tissues.

Results: Our data showed that there were meaningful clinical differences in CT images at different nominal energies. At 40 keV, the necrotic area of the tumor was clearly seen compared with CT images at 120 kVp and 190 keV. More significant differences were found at the rectal tumor border among different energies. For one patient the 40 keV CT image showed the tumor infiltration into the seminal vesicles while the gap was clearly seen between the tumor and seminal vesicles on both 120 kVp and 190 keV images, respectively.

Conclusion: It was demonstrated that the composition and boarder of the rectal tumor are significantly different among the CT images reconstructed for different energies. In order to contour the gross tumor volume accurately MR imaging is recommended.

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