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DIGITAL RADIOGRAPHY. DA 105. Dental Radiography. Questions What equipment is used in digital radiography? What types of digital imaging are available? What are advantages and disadvantages of digital radiography?. Basic Concepts. Used to record radiographic images

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  2. Dental Radiography • Questions • What equipment is used in digital radiography? • What types of digital imaging are available? • What are advantages and disadvantages of digital radiography?

  3. Basic Concepts • Used to record radiographic images • No film or processing chemistry is used • Uses an electronic sensor and computerized imaging system that produces x-ray images almost instantly on a computer monitor

  4. Terminology • Charge-coupled device • Digital radiography • Digital subtraction • Digitize

  5. Terminology • Direct digital imaging • Indirect digital imaging • Pixel • Sensor • Storage phosphor imaging

  6. Purpose and Use • To generate images that can be used in the diagnosis and assessment of dental disease

  7. Purpose and Use • To detect lesions, diseases and conditions of the teeth and surrounding structures • To confirm or classify suspected disease • To provide information during dental procedures • To evaluate growth and development • To illustrate changes secondary to caries, periodontal disease, or trauma • To document the condition of a patient at a specific point in time

  8. Fundamentals • Digital radiography • A method of capturing a radiographic image using a sensor, breaking it into electronic pieces, and presenting and storing the image using a computer • Image is used to describe the pictures that are produced • A sensor is placed inside the mouth • The electronic signal is digitized

  9. Radiation Exposure • The typical sensor is more sensitive to x-rays than conventional film • Exposure times are 50% to 80% less than that required for conventional radiography using E-speed film

  10. Equipment • X-radiation source • Intraoral sensor • Charge-coupled device • Complementary metal oxide semiconductor/active pixel sensor • Charge injection device • Computer

  11. The radiographic image on the computer monitor is displayed as a normal periapical and a magnified version of the same image.

  12. Computer monitor illustrating a variety of images, including panoramic and cephalometric images

  13. X-Radiation Source • Most digital radiography systems use a conventional dental x-ray unit as the x-radiation source • The x-ray unit timer must be adapted to allow exposures in a time frame of 1/100 of a second

  14. A conventional source of x-radiation is compatible with digital imaging

  15. Intraoral Sensor • A small detector that is placed in the mouth of the patient and used to capture the radiographic image • Wired • The imaging sensor is linked by a fiber optic cable to a computer • Wireless • The imaging sensor is not linked by a cable

  16. An intraoral film is similar in size and shape to a sensor used in digital imaging

  17.   A wired intraoral sensor

  18. Intraoral Sensor • Three types of direct sensor technologies exist • Charge-coupled device • Complementary metal oxide semiconductor/active pixel sensor • Charge injection device

  19. Charge-Coupled Device (CCD) • The most common image receptor used in dental digital radiography • A solid-state detector that contains a silicon chip with an electronic circuit embedded in it • The electrons that make up the silicon CCD can be visualized as being divided into an arrangement of blocks or picture elements known as pixels • Pixel • A small box or “well” into which the electrons produced by the x-ray exposure are deposited

  20. Charge-Coupled Device (CCD) • The x-ray photons that come into contact with the CCD cause electrons to be released from the silicon and produce a corresponding electronic charge • Each pixel arrangement, or electron potential well, contains an electronic charge proportional to the number of electrons that reacted within the well • Each electronic well corresponds to a specific area on the linked computer screen

  21. Complementary Metal Oxide Semiconductor/Active Pixel Sensor (CMOS/APS) • Schick technologies uses a CMOS/APS sensor instead of a CCD • The chip is less expensive to produce and offers greater durability than the CCD

  22. Charge Injection Device (CID) • A silicon-based solid-state imaging receptor much like the CCD, but it is different structurally • No computer is required to process the image

  23. Computer • Used to store the incoming electronic signal • Converts the electronic signal from the sensor into a shade of gray that is viewed on the computer monitor • The computer digitizes, processes, and stores information received from the sensor • An image is recorded on a computer monitor in 0.5 to 120 seconds • Has split screen and magnification capability

  24. The image on the computer monitor can be manipulated to enhance density and contrast

  25. A periapical image is displayed on the computer monitor

  26. The image on the computer monitor reveals split-screen technology; two clinical views and two radiographic views are displayed simultaneously

  27. Types of Digital Imaging • Direct Digital Imaging • Indirect Digital Imaging • Storage Phosphor Imaging

  28. Direct Digital Imaging • Components include an x-ray machine, an intraoral sensor, and computer monitor • A sensor is placed into the mouth of the patient and exposed • The sensor captures the radiographic image and transmits it to the computer monitor • Software is used to enhance and store the image

  29. A film-holding device secures the wired sensor

  30. Indirect Digital Imaging • Components include a CCD camera and a computer • An existing x-ray film is digitized using a CCD camera • The image is displayed on a computer monitor

  31. Storage Phosphor Imaging • A wireless digital radiography system • A reusable imaging plate coated with phosphors is used instead of a sensor with a fiber optic cable • The phosphor-coated plates are flexible and fit into the mouth • A high-speed scanner is used to convert the information into electronic files • This type of digital imaging is less rapid than direct digital imaging

  32.   A storage phosphor imaging sensor in place within the film-holding device

  33. A storage phosphor imaging system, illustrating the laser scanning device and the intraoral and extraoral sensors; the resultant full mouth series is viewed on the computer monitor

  34. Step-by-Step Procedures • Sensor Preparation • Sensor Placement

  35. Step-by-Step Procedures • It is critical to refer to the manufacturer-provided instruction booklet for information concerning the operation of the system, equipment preparation, patient preparation, and exposure

  36. Sensor Preparation • Each sensor is sealed and waterproofed • The sensor must be covered with a disposable barrier because it cannot be sterilized

  37. Sensor Placement • The sensor is held in the mouth be bite-block attachments or devices that aim the beam and sensor accurately • The paralleling technique is the preferred exposure method

  38. The intraoral sensor, held by the film-holding device, allows the radiographer to use the paralleling technique for exposure

  39. Advantages of Digital Radiography • Superior gray-scale resolution • Reduced exposure to x-radiation • Increased speed of image viewing • Lower equipment and film cost • Increased efficiency • Enhancement of diagnostic image • Effective patient education tool

  40.  An image seen on the computer monitor reveals interproximal caries

  41. An image displays the feature of digital subtraction; the gray-scale is reversed

  42. Patient education may be easier when a patient can visualize images on a computer monitor

  43. Disadvantages of Digital Radiography • Initial set-up costs • Image quality • Sensor size • Infection control • Legal issues

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