医学影像系统原理7超声分析.ppt

* Thresholding Based on Tri-bar Projection Model Pre-known information: Shape of seed Approximate orientation of the seeds Tri-bar projection model : Project along the bar Calculate the average and the standard deviation in the projected image X axis Z axis Y axis Y Z X * 3D Agar-seed Ultrasound Image 3D image after rendering Tri-bar segmentation * Seed Segmentation Demo * Patient Seed US Image Thresholding Original projection After thresholding * 3D Ultrasound Application:Breast Biopsy Agar phantom Patient breast biopsy * Thank you! * * Image: L2 Ultrasound * * Take out letters * 3D Ultrasound Application: Prostate Brachytherapy Prostate cancer is the second leading cause death of northern American men The American Cancer Institute estimates 230,110 new case, 29,900 dead in 2004. Canadian Cancer Society estimates 20,100 new cases, 4,200 dead in 2004. Prostate cancer is curable at early stage. * Standard Treatments of Prostate Cancer Watchful waiting: Most patients request or need treatment. Radical prostatecotomy: Gold standard but with significant morbidity, such as incontinence and impotence. External beam radiation, such as IMRT: Long treatment time, kill the normal tissue. Prostate brachytherapy: Short stay, safe for normal tissue * Brachytherapy Operation * Side-fire Scanned Transrectal Probe * Needle Tracking and Guidance Under 3D Ultrasound Imaging Need to know where the needle is and where it will go. Determine the tip position of the needle. The processing has to be performed in real-time. * Oblique Needle Insertion * Why is Needle Segmentation in US Images Difficult? Ultrasound image speckle shadows Large 3D image 357 ? 326 ? 352 ? 1 byte = 40 MB High accuracy required Real-time processing (30 fps, or 33 ms per image) * Motivation for Our 3D Needle Segmentation Needle is conspicuous in a projected image. Line object can be reconstructed from two orthogonal projections A