Optimization In Localization Accuracy Of Imaging In Stereotactic Radio Surgery Procedures Using Image Fusion

Thomas Sajeev1, Sampath S1, B IndiraDevi1, G. Bhanumathi1, Mustafa M. M2

1Department of Neurosurgery 2Dept. of Physics, University of Calicut, India

Keywords: image guidance, Imaging, gamma knife, technique, radiosurgery

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     To compare the stereo tactic accuracy of MR images with CT images using Acrylic phantom and Leksell frame with gamma plan 4c planning system and to verify the image fusion option available in the Gamma plan to improve the stereotactic accuracy of gamma knife radio surgery procedures.
     MR images from 1.5 tesla MRI and 4-slice spiral CT –Scan are acquired with fiducial markers with indicator boxes supplied by Elekta Instrument AB .Quality assurance of images are performed before exporting the images to the planning system. In the planning system using the available tools maximum, minimum and mean errors in defining the images are calculated and recorded for 30 patients. The MR images were fused with CT images as reference image and used for evaluation. In both cases the co-ordinates of different isocenters are verified.
     The CT image definitions showed less error compared to MR images. The fusion of MR images with CT images as reference image and vice versa provides an estimation of errors present in each modality of Imaging. The results are tabulated and compared.
     This is a retrospective study.
     Proper evaluation and calibration of Imaging equipments (CT, MRI, DSA)   are very critical in maintaining the stereotactic accuracy of Gamma knife Radiosurgery procedures.
     Adopting Systematic quality assurance procedures and protocols based on the specifications of the equipments and imaging parameters selected are very effective in optimizing the accuracy. Image fusion option available in gamma plan is a powerful tool in optimizing the stereotactic accuracy of Gamma knife Radiosurgery.


Project Roles:

T. Sajeev (), S. S (), B. IndiraDevi (), G. Bhanumathi (), M. M ()