imaging system

• uses photo stimulable phosphor , storage phosphors to produce digital images using existing xray equipment

  computed radiography
• processing data by radiographic means, to produce

  digital images

  computed radiography
• uses digital detector

  computed radiography
• Digital detector designed as flat panel plate.
• X-ray are first converted into light using a phosphor such as

  cesium iodide
• use detectors that convert x-ray directly into electronic signals.

  Direct conversion digital radiography systems
• Uses an array of charge –coupled devices (CCD) instead of an array of electronic elements

  indirect flat panel digital radiography
• CCD are coupled to the scintillator phosphor ,cesium

  iodide.
• radiography of the breast

  digital mammography
• soft tissue imaging

  digital mammography
• Procedures in order to detect breast cancer

  DIGITAL MAMMOGRAPHY
• Allows the observer to use digital image –processing tools to enhance diagnostic interpretation of the image

  digital mammography
• Uses computer aided diagnosis (CAD) software to help radiologists enhance their detection of micro-calcifications and malignant lesion and also provide the so called “second reader” approach.

  digital mammography
• Improve the perception contrast resolution, compared into conventional way.

  digital fluroscopy
• using digital image processing software

  digital fluoroscopy
• uses gray scale processing, temporal frame averaging and edge enhancement

  digital fluoroscopy
• produced dynamic image acquired in real time

  digital fluoroscopy
• Study in motion of the organ system and hollow internal structure: such as GIT and blood circulatory system

  digital fluoroscopy
• consist of x-ray tube, image intensifier (radiation detectors), associated optics (Snell's law) and a television image display or CCD camera tube.

  conventional fluoroscopy
• electrical signal from the TV/CCD system is digitized by the ADC and sent to a computer for image processing.

  output signal
• is also image intensifier tube, it captures the x-ray attenuation data from the px.

  detector
• Digital fluoroscopy to angiography is referred to as Digital Subtraction Angiography (DSA)
• DSA – pre –contrast & post contrast images can be digitally subtracted in real time. To improve perception of low contrast vessels. By subtracting or removing tissue that interfere with visualization of vascular structure.
• which images are subtracted in real time and energy subtraction. In which images are subtracted using different kilovoltages.

  temporal method
• Processing of image using computer -base –system

  digital image processing
• Numerical images suit the viewing needs of radiologist, in an effort to improve and enhanced diagnostic interpretation and management.
• Conceptualized images as subset of all objects, and that image set contains subsets within it, such as visible light and invisible light.
• visible images 


  photographs drawing painting
• invisible image


  temperature pressure elevated maps
• optical image


  holograms
• Images are Scanned from R to L light source (positioned in front of the image ) and (PMT positioned behind of the image ) to detect transmitted light.

  analog images
• The output from a digital radiography detector is an analog (electrical ) signal.
• The result of computer processing is a digital image.
• two image domains

  spatial location and spatial frequency
• Digital image is numerical image arranged that the location of each number in the image can be identified using an X-Y coordinate system
• X-axis describes the horizontal location of the pixel( the column where the pixel is located)
• Y-axis describes the vertical location of the pixel ( the row where the pixel is located)
• Images can also be acquired in the spatial location

  domain.
• Small structures object ( of the px) produce high frequencies represents detail in the image.
• large structure produce low frequencies represent

  contrast information of the image.