Keywords:
Image guidance plays a critical role in radiotherapy to ensure treatment accuracy. Cone-beam CT (CBCT) installed on a medical linear accelerator (LINAC) is routinely used in clinics for this purpose. While CBCT can provide an x-ray attenuation image to guide patient positioning, low soft-tissue contrast affects the delineation of anatomical features, hindering setup accuracy in many cases. To solve this problem, several MRI-LINAC systems have been developed to combine a full diagnostic MRI scanner with a radiotherapy machine. In this paper, we present a new concept for the development of the MRI-LINAC system. Instead of combining a full MRI scanner with the LINAC, we propose to use an interior MRI (iMRI) approach to image a specific region of interest (ROI) containing the radiation treatment target. The iMRI will offer local imaging of high soft-tissue contrast for tumor delineation. Meanwhile, megavoltage CBCT currently available on the LINAC will be used to deliver a global image of the patients anatomy. This paper describes a top-level iMRI system design and its integration to an LINAC platform. Preliminary studies on magnetic field design and imaging capability are also presented.
- Xun Jia
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Steve B. Jiang
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Gary Pickrell
- Department of Materials Science and Engineering, Virginia Tech Blacksburg, VA 24061
- Ge Wang
- Department of Biomedical Engineering, Rensselaer Polytechnic InstituteTroy, NY 12180
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