Rad phy digital radiography

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  • Part No...., Module No....Lesson No Module title IAEA Post Graduate Educational Course in Radiation Protection and Safe Use of Radiation Sources Part …: ( Add part number and title) Module…: ( Add module number and title) Lesson …: ( Add session number and title) Learning objectives: Upon completion of this lesson, the students will be able to: … . (Add a list of what the students are expected to learn or be able to do upon completion of the session) Activity: ( Add the method used for presenting or conducting the lesson – lecture, demonstration, exercise, laboratory exercise, case study, simulation, etc.) Duration: ( Add presentation time or duration of the session – hrs) Materials and equipment needed: (List materials and equipment needed to conduct the session, if appropriate) References: (List the references for the session)
  • Part No...., Module No....Lesson No Module title IAEA Post Graduate Educational Course in Radiation Protection and Safe Use of Radiation Sources Explanation or/and additional information Instructions for the lecturer/trainer
  • Rad phy digital radiography

    1. 1. Digital Radiology
    2. 2. Add module code number and lesson title Digital Radiology <ul><li>Aim : To become familiar with the digital imaging techniques in projection radiography and fluoroscopy. </li></ul>
    3. 3. Add module code number and lesson title Transition from conventional to digital radiology <ul><li>Digital images can be numerically processed </li></ul><ul><li>Digital images can be easily transmitted through networks and archived </li></ul><ul><li>Attention should be paid to the potential increase of patient doses due to tendency of : </li></ul><ul><ul><li>producing more images than needed </li></ul></ul><ul><ul><li>producing higher image quality not necessarily required for the clinical purpose </li></ul></ul>
    4. 4. Add module code number and lesson title What is “dynamic range”? <ul><li>Wide dose range to the detector, allows a “ reasonable ” image quality to be obtained </li></ul><ul><li>Flat panel detectors (discussed later) have a dynamic range of 10 4 (from 1 to 10,000) while a screen-film system has approximately 10 1.5 </li></ul>
    5. 5. Add module code number and lesson title Characteristic curve of CR system HR-III CEA Film-Fuji Mammofine CR response Air Kerma (mGy) 0.001 0.01 0.1 1 3.5 3 2.5 2 1.5 1 0.5 0 Density
    6. 6. NUMERO Analogue versus digital Digital: A given parameter can only have discrete values Analogue: A given parameter can have continuous values
    7. 7. Add module code number and lesson title What is digital radiology? <ul><li>In conventional radiographic images, spatial position and blackening are analogue values </li></ul><ul><li>Digital radiology uses a matrix to represent image </li></ul><ul><li>A matrix is a square or rectangular area divided into rows and columns. The smallest element of a matrix is called ”pixel” </li></ul><ul><li>Each pixel of the matrix is used to store the individual grey levels of an image, which are represented by positive integer numbers </li></ul><ul><li>The location of each pixel in a matrix is encoded by its row and column number (x,y) </li></ul>
    8. 8. Add module code number and lesson title Digital radiology process <ul><li>Image acquisition </li></ul><ul><li>Image processing </li></ul><ul><li>Image display </li></ul><ul><ul><li>Importance of viewing conditions </li></ul></ul><ul><li>Image archiving (PACS) </li></ul><ul><li>Image retrieving </li></ul><ul><ul><li>Importance of time allocated to retrieve images </li></ul></ul>
    9. 9. Add module code number and lesson title Digitizing conventional films <ul><li>Conventional radiographic images can be converted into digital information by a “ digitizer ”, and electronically stored </li></ul><ul><li>Such a conversion also allows some numerical post-processing </li></ul><ul><li>Such a technique cannot be considered as a “ digital radiology” technique. </li></ul>
    10. 10. Add module code number and lesson title Different number of pixels per image: original was 3732 x 3062 pixels x 256 grey levels (21.8 Mbytes). Here, resized at 1024 x 840 (1.6 MB).
    11. 11. Scintillation-based DR Gadolinium Oxy-sulphide Detector
    12. 12. Add module code number and lesson title Digital Radiography Systems <ul><li>Phosphor photostimulable plates (PSP). </li></ul><ul><ul><li>So called CR ( computed radiography ) </li></ul></ul><ul><ul><li>Conventional X-ray systems can be used </li></ul></ul><ul><li>Direct digital registration of image at the detector (flat panel detectors). </li></ul><ul><ul><li>Direct conversion (selenium) </li></ul></ul><ul><ul><li>Indirect conversion (scintillation) </li></ul></ul>
    13. 13. Add module code number and lesson title Computed Radiography (CR) <ul><li>CR utilises the principle of photostimulable phosphor luminescence </li></ul><ul><li>Image plate made of a suitable phosphor material are exposed to X-rays in the same way as a conventional screen-film combination </li></ul><ul><li>The CR image plate retains most of the absorbed X-ray energy, in energy traps , forming a latent image </li></ul>
    14. 14. Add module code number and lesson title <ul><li>A scanning laser is then used to release the stored energy producing luminescence. </li></ul><ul><li>The emitted light , which is linearly proportional to the locally incident X-ray intensity is detected by a photo multiplier/ADC configuration and converted to a digital image </li></ul><ul><li>The resultant images have a digital specification of 2,370 x 1,770 pixels (for mammograms) with 1,024 grey levels (10 bits) and a pixel size of 100 mm corresponding to a 24 x 18 cm field size </li></ul>Computed Radiography (CR)
    15. 15. Add module code number and lesson title The principle of PSP Excitation Storage Emission CB Trap ADC PMT
    16. 16. Add module code number and lesson title كــريــستــال هــالـيــد فــلــوريــد بــاريــم فــعــال شــده بـا يــوروپــيــوم ( Europium Activated Barium FluoroHalide) BaFX:Eu , (X= Cl, Br, or I)
    17. 17. Add module code number and lesson title
    18. 18. Add module code number and lesson title (Images courtesy of AFGA) PSP digitizer Casette and PSP Workstation
    19. 19. Add module code number and lesson title DR Detecting Systems
    20. 20. Add module code number and lesson title
    21. 21. Add module code number and lesson title <ul><li>Direct vs indirect conversion detectors </li></ul>
    22. 22. Add module code number and lesson title CCD Based Detection System
    23. 23. Add module code number and lesson title
    24. 24. Add module code number and lesson title
    25. 25. Add module code number and lesson title Digital detector
    26. 26. Add module code number and lesson title Amorphous Selenium Detector
    27. 27. Add module code number and lesson title Digital fluoroscopy <ul><li>Digital fluoroscopic systems are mainly based on the use of image intensifiers (I.I.) </li></ul><ul><li>In conventional systems the output screen of the I.I. is projected onto a video camera system or a CCD camera </li></ul><ul><li>The output signals of the camera are converted into a digital image matrix (1024 x 1024 pixel in most systems). </li></ul><ul><li>Some new systems start to use flat panel detectors instead of image intensifier. </li></ul>
    28. 28. Add module code number and lesson title
    29. 29. Add module code number and lesson title
    30. 30. Add module code number and lesson title Tendency to increase dose ? <ul><li>For digital detectors, higher doses result in a better image quality (less “noisy” images) </li></ul><ul><li>When increasing dose, the signal to noise ratio is improved </li></ul><ul><li>Thus, a certain tendency to increase doses could happen specially in those examinations where automatic exposure control is not usually available. </li></ul>
    31. 31. Add module code number and lesson title The digital radiology department <ul><li>In addition to the X-ray rooms and imaging systems, a digital radiology department has two other components: </li></ul><ul><ul><li>A R adiology I nformation management S ystem ( RIS ) that can be a subset of the hospital information system ( HIS ) </li></ul></ul><ul><ul><li>A P icture A rchiving and C ommunication S ystem ( PACS ). </li></ul></ul>
    32. 32. Add module code number and lesson title HIS Broker RIS Voice Rec. Server Transcription Pool Radiologist WorkStation E-gate Results To Webserver DICOM Images Verified HL7 HL7 HL7 <ul><li>Modality Worklist Information </li></ul>
    33. 33. Add module code number and lesson title Data management <ul><li>We write a report! </li></ul><ul><li>Link both PACS and RIS. </li></ul><ul><li>Report compares Orders on RIS with Images on PACS. </li></ul><ul><li>Report highlights RIS orders with No images! </li></ul>PACS RIS
    34. 34. Add module code number and lesson title DICOM <ul><li>DICOM (Digital Imaging and Communications in Medicine) is the industry standard for transferal of radiological images and other medical information between different systems </li></ul><ul><li>All recently introduced medical products should therefore be in compliance with the DICOM standard </li></ul><ul><li>However, due to the rapid development of new technologies and methods, the compatibility and connectivity of systems from different vendors is still a great challenge </li></ul>
    35. 35. Add module code number and lesson title DICOM format images: <ul><li>Radiology images in DICOM format contain in addition to the image, a header , with an important set of additional data related with: </li></ul><ul><ul><li>the X ray system used to obtain the image </li></ul></ul><ul><ul><li>the identification of the patient </li></ul></ul><ul><ul><li>the radiographic technique, dosimetric details, etc. </li></ul></ul>

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