Quality assurance of the radiotherapy workflow integrating a dedicated wide-bore 3T MRI simulator
With the advent of high-field MRI scanners specially designed for modern radiotherapy planning and simulation (also known as MRI simulator), more and more oncology centres are introducing MRI into their radiotherapy workflow. A dedicated wide-bore 3T MRI simulator was integrated into our clinical workflow for various treatment sites including head and neck, pelvis, breast, cervix and lung. Patients are scanned first on a 4D CT simulator and then on the MRI simulator in the same setup position as treatment. CT and MRI images are transferred to the treatment planning system for registration. The target volume is then contoured on MRI and transferred to CT images for dose calculation and planning. In order to test the accuracy and consistency of this procedure a quality assurance (QA) program was developed using a suitable MR and CT compatible phantom. Results demonstrate the MRI-integrated workflow implemented in our centre was consistent and reproducible. It is recommended that this QA be performed quarterly or after MRI simulator major repair or maintenance.