Print Version

Effective: Summer 2015

Prerequisites: Prerequisite: R T 52C.
Grade Type: Letter Grade Only
Not Repeatable.
FHGE: Non-GE Transferable: CSU
2.5 hours lecture, 3 hours laboratory (laboratory meets once per quarter). (33 hours total per quarter)

Student Learning Outcomes -
  • Assess the application and components of a digital radiography system in order to maximize radiation protection of the patient in the clinical setting.
  • Describe the components of both computed radiography and direct radiography equipment in conjunction with the process of image formation.
Description -
Imparts an understanding of components, principles and operation of digital imaging systems found in diagnostic radiology. Factors that impact image acquisition, display, archiving and retrieval are discussed. Compare/contrast digital and film-based systems. Principles of digital system quality assurance and maintenance. Intended for students in the Radiologic Technology Program; enrollment is limited to students accepted in the program.

Course Objectives -
The student will be able to:
  1. Differentiate between pixel size, matrix size, and bit depth.
  2. Compare and contrast the cassette-less digital system with the cassette-based digital system.
  3. Evaluate the pros and cons of the characteristics that are inherent to a digital radiographic system.
  4. Compare the dynamic range of digital detectors with the latitude of optimal image acquisition.
  5. Categorize the process of data acquisition in both a cassette-less and cassette-based digital system.
  6. Categorize the process of image extraction in both a cassette-less and cassette-based digital system.
  7. Describe the methods of post-processing in both a cassette-less and cassette-based digital system.
  8. Evaluate the exposure indicators of vendor specific software and ascertain the pros and cons of each.
  9. Document the effects of scatter radiation on film and a digital imaging plate and discuss how image quality of each system is affected.
  10. Evaluate various errors and artifacts and how they affect image quality.
  11. Describe quality control methods and tools to assess accurate image formation.
  12. Describe the PACS system.
  13. Relate the HIPAA and patient confidentiality issues that arise with digital imaging and electronic records.
  14. Appraise the radiation protection pitfalls resulting with a digital imaging system.
Special Facilities and/or Equipment -
  1. Multimedia classroom
  2. Digital radiology laboratory
  3. Digital QC equipment
  4. Large flat panel monitor
  5. Internet access

Course Content (Body of knowledge) -
  1. Digital image characteristics (Lec)
    1. Picture elements - pixels
    2. Pixel size
    3. Matrix size
    4. Spatial resolution
    5. Bit depth
    6. Information content - megabytes/image
  2. Digital receptors (Lec)
    1. Cassette-less systems
      1. Thin film transistors (TFT) arrays
      2. Charge coupled device (CCD) and complementary metal oxide semiconductor (CMOS) systems
        1. Linear scanning arrays
          1. Fixed photostimulable phosphor (PSP) plates
        2. Optically coupled cameras
          1. Phosphor structure
          2. Detector characteristics
    2. Cassette-based systems
      1. PSP plates
        1. Turbid phosphors
        2. Structured phosphors
  3. Comparison of detector properties and evaluative criteria (Lec)
    1. Detective quantum efficiency (DQE) predicts dose efficiency
    2. System speed vs. ‚ƒ๚speed class‚ƒ๙ operation
    3. Spatial resolution
      1. Cassette-based systems
        1. Sampling frequency ‚ƒ์ pixel pitch
        2. Receptor size vs. sampling frequency
        3. Light spread ‚ƒ์ phosphor layer thickness
      2. Cassette-less systems ‚ƒ์ detector element size
    4. Advantages over film-screen
      1. Increased dynamic range
      2. More contrast resolution
    5. Limitation relative to film-screen
      1. Lower spatial resolution
      2. Strong dependence of image quality on
        1. Image processing
        2. Display characteristics
  4. Dynamic range vs.latitude (L-L)
    1. Dynamic range of the detector
      1. Acquisition data width
      2. Greater than film-screen
    2. Latitude ‚ƒ์ allowable error for optimal image acquisition
      1. Actual exposure latitude is approximately double that of film-screen
        1. 50% below ideal causes mottle
        2. Greater than 200% above ideal results in loss of contrast
      2. Beam-part-receptor alignment latitude less than film-screen
  5. Raw data acquisition ‚ƒ์ ‚ƒ๚latent image‚ƒ๙ (L-L)
    1. Positioning
    2. Exposure field alignment and collimation
      1. Cassette-less system
      2. Cassette-based system
    3. Exposure ‚ƒ์ technique selection
  6. Image extraction (L-L)
    1. Cassette-less
      1. Rows and columns read line by line
      2. Data transferred to external electronics
      3. Digitized by analog to digital converter(ADC)
      4. Histogram created and analyzed by software
      5. Initial image processing
        1. Exposure field recognition
        2. Histogram analysis
        3. Automatic rescaling ‚ƒ์ risk of failure
    2. cassette-based system
      1. Plate scanned by laser
      2. Signal data digitized by ADC
      3. Exposure field(s) identified
      4. Histogram created and analyzed by software
      5. Initial image processing
        1. Exposure field recognition
        2. Histogram analysis
        3. Exposure index determination
  7. Post-processing (L-L)
    1. Gradient processing
      1. Brightness
      2. Contrast
    2. Frequency processing
      1. Smoothing
      2. Edge enhancement
    3. Equalization
  8. Exposure indicators (L-L)
    1. Cassette-less systems
      1. Dose area product (DAP)
        1. Actual patient dose of calibrated
        2. No established DAP standard
        3. Receptor exposure not indicated
      2. Relationship to patient exposure
        1. Exposure indicator ‚ƒ์ ‚ƒ๚speed class‚ƒ๙
        2. Reached exposure index (REX)
    2. Cassette-based systems
      1. Vendor specific values
        1. Sensitivity (‚ƒ๚S‚ƒ๙)
        2. Exposure index (EI)
        3. Log mean exposure (LgM)
      2. Relationship to patient exposure
      3. Reader calibration
      4. Centering and beam collimation
      5. Optimal value ranges
    3. Exposure field recognition
      1. Single field patterns ‚ƒ์ collimation margins and alignment
      2. Multiple exposure fields ‚ƒ์ optimal patterns
  9. Affects of scatter (L-L)
    1. Low intensity radiation response
      1. Background
        1. Cassette-less system constantly refreshed
        2. Cassette-based system plate is storage phosphor
          1. Stores background exposure
          2. Plate responds to an exposure as low as 60 μR
          3. Background is 40 μR/day to 80 μR/day
          4. Plates unused for more than 48 hours should be erased
    2. Scatter defined
      1. More intense than background
      2. Scatter control becomes critical
    3. Scatter control
      1. Beam limiting
      2. Optimal exposure - overexposure produces more scatter
      3. Grid use
        1. Kilovoltage(kVp) conversion preferred
        2. Grid cutoff produces low contrast
        3. Compare short dimension (SD) grid and long dimension(LD)grid
        4. Moir?© effect
          1. Grid frequency approximately equal to Nyquist
          2. Reduce risk ‚ƒ์ unmatched frequencies
            1. Grid frequency less than Nyquist (178 lpi)
            2. Grid frequency greater than Nyquist(103 lpi)
    4. Recognition of image processing errors that affect image clarity (Lec)
      1. Histogram analysis error
        1. Incorrect anatomic menu selection
        2. Exposure field not detected
          1. Collimation border recognition
          2. Exposure field distribution ‚ƒ์ multiple fields/plate
        3. Unexpected material in data set, i.e., metal
        4. Large exposure error ‚ƒ์ plate saturation
        5. Inappropriate rescaling ‚ƒ์ dark or light image
        6. Effects of excessive processing
    5. Quality Control (Lec)
      1. Initial acceptance testing
      2. Cassette-based system reader preventive maintenance (PM)
      3. Plate maintenance
      4. Reject analysis
    6. Picture archiving and communication system (PACS) (Lec)
      1. Terminology
      2. System components and function
        1. Image manipulation
        2. Access to report information
        3. Access from multiple locations
        4. Image retrieval
        5. Back-up systems
      3. Digital imaging and communication in medicine (DICOM)
      4. Monitor
        1. Liquid crystal display (LCD)
        2. Cathode ray tube (CRT)
      5. Patient confidentiality (Lec)
        1. HIPAA
        2. Image access
        3. Lack of patient history due to confidentiality issues
        4. Image notation
        5. Transmitting images electronically
      6. Exposure myths associated with digital systems (Lec)
        1. Milliampere-seconds(mAs)
        2. kVp
        3. Collimation
        4. Grid
        5. SID
        6. Speed class
        7. Fog
Methods of Evaluation -
Methods of evaluation may include, but are not limited to:
  1. Quizzes
  2. Lab Report
  3. Midterm
  4. Comprehensive Final exam
  5. Participation in class discussion.
  6. Process reflection paper
Representative Text(s) -
Seeram, Euclid. Digital Radiology: An Introduction for Technologists. 1st edition. United States: Delmar Cengage Learning, 2010.
ISBN: 978-1-4018-8999-9
Fauber, Terri. Radiographic Imaging & Exposure. 3rd edition. St. Louis, MO: C.V. Mosby, 2009.
ISBN: 978-1-4377-6801-5
Instructor: Course Syllabus

Disciplines -
Radiologic Technology
Method of Instruction -
Methods of instruction may include, but are not limited to lecture, discussion, cooperative learning exercises, laboratory, and demonstration.
Lab Content -
  1. Digital Technical Lab Experiments
    1. Compare CR versus Analog Imaging Systems
      1. CR Cassette
        1. Image Quality
        2. Dynamic Range
        3. Exposure Index
        4. Histograms
        5. Scatter
      2. Analog Film Cassette
        1. Image Quality
        2. Dynamic Range
        3. Visual Exposure Cues
          1. Density
          2. Contrast
        4. Scatter
Types and/or Examples of Required Reading, Writing and Outside of Class Assignments -
  1. Reading Assignments: Weekly reading assignments from text and outside sources.
  2. Reflection paper comparing and contrasting digital and analog imaging systems.