医学影像原理介绍.ppt

醫學影像原理介紹 History 1895 : William K. Roentgen discovered X-rays. 1901~1930: intensifying screen, tomography, and the rotating anode tube. ~1970: nuclear medicine .ultrasound, CT, ~ 1980: PET, MRI, Microwave. ~future: multi-modality image system, PACS 放射醫學影像介紹 何謂醫學影像 醫學影像種類 傳統X光影像 特殊攝影影像 電腦斷層影像 核磁共振斷層影像 核子醫學造影影像 其他影像 醫學影像資訊 結構性影像資訊 CT, MRI, X-ray, Ultrasound 功能性影像資訊 Functional-MRI, Nuclear Medicine 融合影像資訊 CT-SPECT, MRI-SPECT CT-PET,MRI-PET CT-MRI Camera principle MEDICAL IMAGE EQUIPMENT EM WAVE SPECTRUM Image Signal Transmission Emission Magnetic field Ultrasound Other: Microwave, laser…. Radiation Ionization: 非粒子輻射 X, r –ray Non-ionization: 又稱為粒子輻射 Particle: X-ray basic principle X-ray introduction What is X-ray? Interactions between X-ray and Matter (1) Coherent Scattering (2) Photoelectric Effect (3) Compton Scattering (4) Pair production (5) Photodisintegration Coherent scattering Photoelectric effect Compton Scatter Par production X-RAY DTETCTORS To produce an image from the attenuated X-ray beam, the X-rays need to be captured and converted to image information. Two system for the X-RAY detectors: Screen-Film detector Detectors for computer radiography Schematic representation of the radiographic image chain X-ray tube X-ray Tube X-ray generator X-ray detectors X-ray Film The X-ray Film is a photographic film consisting of a transparent plastic substrate made of acetate or polyester usually coated on both sides with a light-sensitive emulsion. Optical Density D= Log10(Ii/It) D : the optical density Ii : incident light intensity It : transmitted light intensity X-ray Film 診斷型X光機 血管攝影X光機 移動型X光機與C型X光機 數位型X光機 Clinical Application Clinical Application 傳統式X光的缺點 2D projection of 3D structure Lost depth information Overlapping plane Can not differ soft tissue Can not quantitative X-Rays Computer Tomography Basic Scanning produre in CT Basic Scanning produre in CT CT generation