S-Y Lisa Grimm

Albert Einstein Medical Center, Philadelphia, Pennsylvania, United States

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Publications (2)2.96 Total impact

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    ABSTRACT: A computed tomography (ct) scanner on Rails has been installed in a linear accelerator room at Morristown Memorial Hospital since 2000. The ct-on-Rails has been used for the localization of patient position during radiation delivery for prostate, lung and liver cancer patients. The image management system, the Siemens Syngo system, is the primary software employed in the registration of the planning ct and the treatment ct images. This study compares the two image fusion methods available in the system: Landmark Registration and Visual Alignment. Shifts in 6 ct scans with Rando phantom were deduced from Landmark Registration (automatic algorithm) and from Visual Alignment (manual registration), and compared with the shifts directly measured on the phantom. For Visual Alignment, the isocenter shifts deduced from the fused images generally agreed well with the directly measured shifts on the Rando phantom, with average absolute error of 0.9 mm in anterior-posterior (ap) direction, 1.0 mm in right-left (rl) direction, and 2.0 mm in superior-inferior (si) direction. The image fusion algorithm was confirmed to be accurate. Some scans with Landmark Registration gave erroneous ap shifts when the anterior radio-opaque marker (bb) registration was of in the ap direction. Visual Alignment was more robust than Landmark Registration in these clinical situations.
    Physica Medica 07/2005; 21(3):113-9. · 1.85 Impact Factor
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    ABSTRACT: A computed tomography (CT) scanner was installed in the linear accelerator room (Primatom) at Morristown. Since June 2000, we have been providing prostate, lung, and liver cancer patients with fusion of CT and linac radiation treatment. This paper describes our registration methods between planning and treatment CT images, and compares treatment localization by CT versus conventional localization by bony landmarks such as portal imaging. For image registration, we printed out beforehand the beam's eye view of the treatment fields. Prostate tumor volume from each Primatom CT slice was mapped on the printouts, and the necessary isocenter shift relative to the skin marks was deduced. No port film was necessary for our Primatom patients. For ten patients we generated digitally-reconstructed radiographs (DRRs) with bone contrast from the CT scans, and deduced the required shift as the difference between the DRRs of the Primatom CT versus the planning CT. This represented the best observable shift should portal imaging be employed. Shift from bony landmark significantly correlated with the Primatom CT shift. Positioning adjustment based on bony anatomy was generally in the same direction as the CT shift for individual patient, but frequently did not go far enough. Our study confirmed that prostate organ motion relative to the bones has an average length of 4.7 mm (with standard deviation of 2.7 mm), and indicated the superiority of CT versus conventional bony structure (such as portal imaging) localization.
    Journal of Applied Clinical Medical Physics 02/2003; 4(2):112-9. · 1.11 Impact Factor