Room: Exhibit Hall | Forum 9
Purpose: To report improvements of image quality and structure delineation from simultaneous dual-energy CT (DECT) as compared to both sequential DECT and conventional (single-energy) CT for radiation treatment (RT) planning of pancreatic cancer.
Methods: Data analyzed include (1) DECT and CT data acquired for 10 consecutive pancreatic cancer patients using a conventional 120 kVp protocol with IV contrast at the late arterial phase and a simultaneous DECT protocol at 80 and 140 kVp on a scanner (Drive, Siemens) during RT simulation, and (2) sequential and simultaneous DECTs acquired for selected pancreatic cancer patients using an in-room CT during CT-guided RT delivery (Definition, Siemens). Mono-energetic decomposition CTs (MDCTs) from 40 keV to 120 keV were derived from the DECT in 10 keV increments. The pancreas and the duodenum were delineated in each image. The image quality for each CT set was measured by the contrast (defined as the difference in mean CT number between the two structures), the noise, and the contrast to noise ratio (CNR). The diameter of the celiac artery was measured in MDCTs derived from both simultaneous and sequential DECTs to compare the motion blurring between the two acquisitions.
Results: The contrast between the pancreas and duodenum was increased substantially with low energy (40-70 keV) MDCTs, with average contrast increased from 48.9 HU for the conventional CT to 135.5 HU for the 40 keV MDCT from simultaneous DECT. As the energy of the MDCT decreased, the image noise increased. The CNR reached its maximum at 40 keV MDCT. The average diameter of the celiac artery was reduced by 3 mm in the simultaneous DECT in comparison to the sequential DECT.
Conclusion: Compared to conventional CT and sequential DECT, simultaneous DECT improves structure delineation for RT planning for pancreatic cancer by enhancing image contrast while preserving spatial resolution.
Funding Support, Disclosures, and Conflict of Interest: Supported by Siemens Healthineers