MRI-Guided Targeted Prostate Cancer Radiation Therapy: Multi-Image Co-Registration
A Bao*, Y Zheng, R Ellis, J Fabien, C Rhodes, V Colussi, B Wessels, University Hospitals Case Medical Center, Cleveland, OHSU-E-T-263 Sunday 3:00PM - 6:00PM Room: Exhibit Hall
Purpose: MRI has been used for guiding treatment planning and post-treatment evaluation in prostate cancer targeted radiation therapy. However, the co-registration of MR images to CT or ultrasound images needs manual adjustment due to the motion of the pelvic organs. To improve the accuracy of the co-registration of MR images to CT or ultrasound images, we investigated the use of simultaneous image co-registration of multiple MR images to CT or ultrasound images utilizing MIM™ software.
Methods: Multiple MR images, including T1 without and with Gd-contrast agent, T2, and diffusion weighted images were acquired using the same preview image allowing MR images to be inherently co-registered. By using MIM™ image fusion software, multiple MR images were simultaneously fused with either CT or ultrasound image. Adjustment of CT/MR image co-registration uses the best contrast information from one or multiple MR images at each micro-structure location. The alignment of individual MR image was then adjusted to account for their individual contrast characteristics.
Results: Thirty seven prostate cancer patients were studied using this image co-registration method. By using this strategy, T2-weighted MR images can be accurately matched to CT images with <2 mm of the prostate margin. Newly acquired T1-weighted MR images can be fused accurately to pelvic bones, prostate and pelvic lymph nodes. However, the alignment of the rectum, bladder, and bowel can vary.
Conclusion: The simultaneous multiple MR image co-registration technique provides a strategy of efficient multiple MR image co-registration, while improving the accuracy of image co-registration. This image co-registration technique has also been used in other locations, such as the spine.