Program Information
Slice-Stacking T2-W MRI for Fast Determination of Internal Target Volume (ITV) for Liver Cancer
S Han1*, F Yin2 , B Czito3 , M Palta4 , J Cai5 , (1) Duke University Medical Physics Graduate Program, Durham, NC, (2) Duke University Medical Center, Durham, NC, (3) Duke University Medical Center, Durham, NC, (4) Duke University Medical Center, Durham, NC, (5) Duke University Medical Center, Durham, NC
Presentations
TU-FG-FS2-11 (Tuesday, August 1, 2017) 1:45 PM - 3:45 PM Room: Four Seasons 2
Purpose: T2-w echo-planar fast spin echo sequence (HASTE) has been used for 4D-MRI due to its superior tumor contrast compared to CT and other MR sequences. However, due to its sequential acquisition scheme, the imaging time is long and typically requires 15-20 repeated scans (10-15 minutes). The aim of this study was to investigate the feasibility of fast determining internal target volume (ITV) based on slice-stacking of the HASTE MR sequence.
Methods: A 4D XCAT digital phantom with regular and irregular motions, and a liver cancer patient were used to develop the method. A hypothetical spherical tumor (3 cm diameter) was inserted in the liver of the XCAT phantom. Image acquisition of HASTE was simulated on XCAT using a method previously developed by our group. The image acquisition was repeated more than 15 times for the volume of interest. Maximum intensity projection (MIP) images were generated and ITV was determined using the slice-stacking method after each repeated scan, and compared to the reference ITV generated from all repeated scans using Dice’s similarity coefficient (DSC) and volume difference.
Results: DSC of ITV increases and ITV volume difference decreases as the number of repeated scans increases in an inverse exponential manner. For the XCAT study, the mean DSC of ITV is > 0.95 and the mean ITV volume difference is < 0.4 cm3 after 5 repeated scans for both regular and irregular motions. For the patient, the ITV volume difference is < 3% after 5 repeated scans.
Conclusion: It is feasible to quickly generate clinically acceptable ITV using slice-stacking on T2-w HASTE MR sequence. The imaging time is 2-3 times less than that of 4D-MRI.
Funding Support, Disclosures, and Conflict of Interest: Varian Medical System
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