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醫療影像處理在診斷上之應用. 嘉義大學資工系 教授 柯建全 時間 : 2010 年 5 月 3 日. Outline. Introduction Object of medical image processing Imaging devices applications Related techniques for Medical imaging Research Results Future works. Introduction. What is Medical imaging?
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醫療影像處理在診斷上之應用 嘉義大學資工系 教授 柯建全 時間: 2010年5月3日
Outline • Introduction • Object of medical image processing • Imaging devices • applications • Related techniques for Medical imaging • Research Results • Future works
Introduction • What is Medical imaging? • Why do we need digital image processing? • What kind of problems are often caused in medical images? • Blurring caused by respiratory or motion • Low contrast caused by imaging device or resolution • Complicated textures • Research trends have been transferred from 2-D to 3-D reconstruction
Introduction (continue) • Integrate all possible methods in the filed of DIP, pattern recognition, and computer graphics • Qualitative • Quantitative • Three categories of imaging in different modalities • Structural image • Functional image • Molecular image
Object • Help physicians diagnose (Computer-assisted diagnosis; CAD) • Reduce inter- and intra-variability • Produce qualitative and quantitative assessment by computer technologies • Determine appropriate treatments according to the analyses • Surgical simulation or skills to reduce possible errors
Medical Imaging Modalities • X-ray • Ultrasound: non-invasive • Computed tomography • Magnetic resonance imaging • SPECT (Single photon emission tomography) • PET( Positron emission tomography) • Microscopy: OM,LSCM, EM, FMAFM, STM
Ultrasound • 2-D sonography • 3-D sonography • Doppler color sonography • A series of 2-D projection • Reconstruction • 4-D sonography
Computed tomography • 無法顯現人體組織和器官功能
MRI • 可以觀察活體三度空間的斷層影像 • 磁振影像取影像時可以適當控制而得到不同參數的影像,如溫度、流場(flow)、水含量、分子擴散( diffusion)、 灌流(perfusion)、化學位移(chemical shift)、功能性(functional MRI) 及不同核種如氫、碳、磷 • 人體內若有金屬物質,可能形成假訊號,造成磁場分佈不 均勻,或是干擾體內儀器運作,所以裝有心律調整器、人工金屬關節、接受腦血管動脈者
Related techniques • Image processing • Pre-Processing • Segmentation • Registration • Feature Extraction • Shape feature • Texture • Motion tracking • Pattern recognition • Supervised learning • Un-supervised learning • Neural network • Fuzzy • Support vector machine (SVM) • Genetic algorithm
Related techniques • 3-D graphic • Virtual diagnose or visualization • Fusion between different modalities • Bio-medical visualization
PET(Positron Emission Tomography ) • PET以分子細胞學為基礎,將帶有特殊標記的葡萄糖合成藥劑注入受檢者體內,利用PET掃瞄儀的高解析度與靈敏度作全身的掃描,藉由癌細胞分裂迅速,新陳代謝特別旺盛,攝取葡萄糖達到正常細胞二至十倍,造成掃描圖像上出現明顯的「光點」 • 能於癌細胞的早期(約0.5公分)準確地判定癌細胞,提供醫師作為診斷及治療的依據,診斷率高達87-91%,30歲以上的成年人及有癌症家族史的民眾,建議每隔1~2年做一次PET檢查。
Cell identification via microscope • Tools • Traditional optical microscope • Stained specimen • Fluorescent microscope • Identification for nuclear and gene expression • Laser confocal microscope • Identification from 2-D to 3-D • Multi-photon microscope • Identification from 2-D to 3-D
Applications in a hospital • Assist surgeon plan surgical operation or diagnose • Picture archiving system (PACS) • 將醫療系統中所有的影像,以數位化的方式儲存,並經由網路傳遞至同系統中,供使用者於遠側電腦螢幕閱讀影像並判讀。 • Telemedicine • Surgical simulation: Medical Visualization,Surgical augmented Reality, Medical-purpose robot, Surgery Simulation,Image Guided Surgery,Computer Aided Surgery • Estimate the location, size and shape of tumor
Related techniques • Classification of normal or abnormal tissues such as carcinoma • Pre-processing: Contrast enhancement, noise removal, and edge detection • Lesion segmentation: extract contours of interest • thresholding • 2-D segmentation • 3-D segmentation based on voxel data • Color image processing
Our study • Virtual colonoscopy • Bone tumor segmentation with MRI and virtual display • Breast carcinoma based on histology and cytology • Visualization of cell activities using confocal laser scanning microscope
Virtual colonscopy-Browsing or navigation within a colon • Helical CT –patients injected contrast medium • Re-sampling—Voxel-based • Interpolation • Automatic segmentation (seed) • threshloding • Determination of the skeleton of the colon • Connected-Component Labeling • Surface rendering and volume rendering • Extraction of suspicious sub-volumes for diagnosis
Bone tumor segmentation with MRI and virtual display—Contrast medium • Otsu thresholding • Region growing • Tri-linear interpolation • Morphological post-processing • Surface rendering • Measurement
應用雷射共軛焦顯微鏡影像三維重構研究螢光細胞之活動-以子宮頸癌細胞為例應用雷射共軛焦顯微鏡影像三維重構研究螢光細胞之活動-以子宮頸癌細胞為例
雷射共軛焦顯微鏡之成像原理 雷射共軛焦顯微鏡解析度: 46
雷射共軛焦顯微鏡雜訊生成之原因 • 大部分的生物樣本,潛在一些特性會降低 CLSM 影像解析度: • 第一個是具有散射的特性 • 第二個特性是折射率的不匹配(refractive-index mismatch)所產生的。 • 由於折射率的不匹配會引入球面像差,而使得縱向與橫向解析度變差。 47
散射的特性 散射光強度: 48
散射的特性 49
研究影像 50