MRI-Guided Targeted Prostate Cancer Radiation Therapy: Imaging, Diagnosis, and Image Co-Registration
A Bao1*, Y Zheng2, S Ware3, V Colussi4, R Ellis5, B Wessels6, (1) University Hospitals Case Medical Center, Cleveland, OH, (2) University Hospitals Case Medical Center, Cleveland, OH, (3) Mayo Clinic Arizona, Phoenix, AZ, (4) University Hospitals Case Medical Center, Cleveland, OH, (5) University Hospitals Case Medical Center, Cleveland, Ohio, (6) Dept of Radiation Oncology, Cleveland, OHSU-E-J-90 Sunday 3:00PM - 6:00PM Room: Exhibit Hall
Purpose: This study investigates using MR imaging for prostate cancer targeted radiation therapy, including using MR imaging to localize tumor in prostate for focused radiation therapy, co-registering MR images to CT or ultrasound images to guide or evaluate cancer radiation therapy, and determining tumor stage and its invasion to locoregional lymph nodes.
Methods: Either endorectal (ER) or body RF coil has been used to acquire MR images. To determine the localization and volume of the prostate tumor from the MR images and to understand their correlation with the pathology slices, both pre-surgery ER coil MR imaging and post-surgery multi-slice pathological analysis of the surgically excised tumor were studied (n=8). To avoid prostate dislocation caused by ER coil, multiple MR imaging protocols using the body coil were implemented to depict the structure of prostate and its surrounding tissues, pelvic lymph nodes, and obtain dynamics of contrast enhancement (n=37). MIM™ software was used to co-register MR images to CT or ultrasound images for guiding treatment planning and evaluating prostate cancer brachytherapy.
Results: The MR diagnosed tumor was proven by prostate pathology, which shows the rationale of using MRI guidance for focused treatment of prostate cancer to decrease toxicity and improve tumor control. It has been demonstrated that the capability of tumor localization and volume determination based on MR images are associated with tumor cell density. CT/MRI and ultrasound/MRI co-registration provides excellent prostate micro-structure, and surrounding tissue information for improved treatment planning, as well as post-treatment evaluation. By using multi-MR image synergistic co-registration, T2-weighted MR images can be accurately matched to CT image with <2 mm alignment error.
Conclusion: MR image guidance is excellent for targeted prostate cancer radiation therapy, and it has been successfully used in our clinical practice.