Room: Exhibit Hall | Forum 2
Purpose: MRIdian (Viewray Inc.), the magnetic resonance image guided radiotherapy (MR-IGRT) system, allows us on-table adaptive radiotherapy (ART). Fusion of magnetic resonance (MR) image and computed tomography (CT) image was necessary to calculate dose distribution on-table ART in MRIdian. Our purpose is to evaluate the accuracy of multi-modality deformable image registration (DIR) in MRIdian by comparison to other DIR software MIM maestro (MIM Software Inc.).
Methods: MR images were acquired by MRIdian for image-guide. CT images were acquired by Aquilion LB (CANON MEDICAL SYSTEMS CORPORATION) to assign electron density map on MR images by DIR procedure. Clinical images were only used in this analysis. The multi-modality DIR based on MR image was done with MRIdian and MIM. Structure delineation was performed in MR image, deformed CT images by MRIdian and by MIM. Dice coefficient and Jaccard coefficient were calculated with the structure on MR as a reference.
Results: The means and the standard deviations of Dice coefficient for liver in five patients were 0.93, 0.014 in MRIdian and 0.92, 0.007 in MIM, respectively. And those of Jaccard coefficient were 0.86, 0.021 in MRIdian and 0.85, 0.013 in MIM. The means and the standard deviations of Dice coefficient for right kidney in five patients were 0.89, 0.060 in MRIdian and 0.93, 0.010 in MIM, respectively. And those of Jaccard coefficient were 0.80, 0.091 in MRIdian and 0.87, 0.017 in MIM. The means and the standard deviations of Dice coefficient for left kidney in five patients were 0.92, 0.014 in MRIdian and 0.94, 0.012 in MIM, respectively. And those of Jaccard coefficient were 0.85, 0.038 in MRIdian and 0.89, 0.019 in MIM.
Conclusion: Dice coefficients and Jaccard coefficients were calculated to evaluate the DIR accuracy of MRIdian and MIM. Accuracy of multi-modality DIR in MRIdian was comparable to MIM maestro.