Liver cancer4D-CT imaging with synchronized intravenous contrast injection to improve delineation of liver tumors for treatment planning
Section snippets
4D-CT procedure
As part of the standard treatment for patients with liver tumors, we use the GE Discovery ST PET/CT scanner (General Electric Co., Waukesha, WI) for 4D-CT image acquisition. The CT scanner in this unit is used to acquire a maximum of eight 2.5-mm slices per couch position. The respiration of the patient is tracked using the Real-Time Position Management (RPM) System (Varian Medical Systems, Palo Alto, CA) [5], [9]. Normal helical scouts for patient positioning and isocenter localization are
Results and discussion
More than 80 patients have been simulated following this protocol since November 2004. Representative images from patients with each of the three common liver tumor types (colorectal liver metastases, cholangiocarcinoma, and hepatocellular carcinoma) are provided in Fig. 1, and data for these three patients are shown in Table 1. For two of the patients, one with liver metastases and the other with intrahepatic cholangiocarcinoma, the liver was imaged during the portal venous phase with a 45-s
Conclusions
Combined 4D-CT imaging with synchronized IV contrast allows for both enhancement of tumor contrast and coverage over the entire breathing cycle. The 4D-CT scans are acquired in the same position and immobilization device as that used for treatment, and thus may improve on the accuracy of tumor contouring and localization. Finally, the resulting tumor contours can be fused with the scans to be used for treatment planning.
Further studies are required, and additional experience from the
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