A Simplistic Approach for Registration of Orthogonal Planar Images as a Pre-Preparation for Externally Acquired Cranial Images in Department of Radiation Oncology, Nayati Healthcare and Research Centre

Accurate image registration for CT-CT, CT-MRI for brain is necessary to obtain clinical information from diagnostic images and translate the information to radiotherapy treatment planning CT images. Mostly in cases of Post-Surgery cases that have been operated outside hospitals and are being referred for Post-Operative adjuvant Radiotherapy to our Centre, where the pre-operative volume is very importantly necessary in radiotherapy planning, a pre preparation was needed. The intention of the work is two folds. One is to make the outside clinic diagnostic images with rectangular matrix dimension compatible with our treatment planning system (TPS), Eclipse version 11. Second use point by point registration in three orthogonal planes as pre-preparation process for specific outside clinic diagnostic images where registration accuracy was not the intention. Both the intentions were handled using in-house developed software in Matlab and the saved registered images were transferred to TPS for auto matching the images for fine tune. Visual inspection of the registration was in good agreement. The mean variation for the dimension of the registered phantom images from the Base image of the phantom were found to be 0.5 mm which was less than 1 pixel value. KeywordsCT-CT, CT-MRI, manual fusion, RT Planning, treatment planning system (TPS), Base image, Input image, Matlab