ct圖像質(zhì)量講義(已改無錯字)
2023-03-10 14:18:25 本頁面
【正文】 描條件，因為這些部位本身具有較高的對比度，少量的噪聲不會影響診斷。 mAs(劑量 ) Gee David Gee David Gee David Gee David 對比噪聲比 CNR 優(yōu)化門脈期圖像的觀察能量閾值，最佳顯示為 52KeV Gee David Gee David CT Artifacts偽影 ?Areas where image not faithful to subject ?Sources ? patient ? image process ? equipment Gee David Motion Artifacts ?Causes streaks in image ?Algorithms have trouble coping because of inconsistent data Gee David Artifacts: Abrupt High Contrast Changes ? Examples: ?prostheses ?dental fillings ?surgical clips ?Electrodes ?bone ? Metal absorbs all radiation in ray ?causes starshaped artifact ? Artifact can be reduced by software Gee David ?Increase in mean energy of polychromatic beam as it passes through patient ?Can cause broad dark bands or streaks ? cupping artifact ?Minimized using beam hardening correction algorithms CT Artifacts: Beam Hardening MARS：減除金屬和硬化偽影 Gee David CT Artifacts: Partial Volume Effect ? CT ’s based on linear attenuation coefficient for tissue voxels ? If voxel nonuniform (contains several materials), detection process will average ? Can appear as ? incorrect densities ? Streaks and bands ? Minimizing ? Use thinner slices Gee David Gee David 謝 謝！ Gee David ?描述 CT 圖像質(zhì)量的三個主要參數(shù) : 空間分辨率、密度分辨率、噪聲 ?對比度 (密度 )分辨率
數(shù)學相關(guān)推薦
鄂ICP備17016276號-1