rad 254 digital imaging basic elements of digital imaging cr/dr
TRANSCRIPT
CD/DR
• Image data CAPTURE
• Image data PROCESSING
• Image DISPLAY
• Image data ARCHIVING
• Image data DISTRIBUTION & TRANSMISSION
Electronic Imaging
• Produce image– Digitize (A-D Converter)
• Process Data– Output or D-A Conversion then Analog
Display» Network» Archive Image
Image Acquisition & Detection
• Image detector types:
– COMPUTED RADIOGRAPHY (CR)• Photostimulable Phosphor (PSP)
– DIRECT RADIOGRAPHY (DDR, “DR”)• Solid State X-ray Detector (SSXD)
CR/DR Differences (steps)
• COMPUTED RADIOGRAPHY(CR)– X-ray – PSP – A-D Conversion – Data
• DIRECT RADIOGRAPHY (DDR, “DR”)– X-ray – SSXD - Data
Image Data Processing
• The selection of processing algorithms, and anatomic regions and radiographic projections controls how the acquired (latent) image is presented for display
Image Display
• In both CR and DR, a separate device MUST be used to display (as well as view) the digitized image (video monitor)
– High resolution (1.5-2.5k matrix)– Diagnostic– Clinical Review– Web based
Image Data Archiving
• Storage and retrieval
• RAID– Storage – Terabyte (Tb) capacity
• Digital Linear Tape (DLT)
• Application Software Provider (ASP)
Image Data Distribution/Transmission
• One of the greatest strengths of a digital imaging system is the ability to share images simultaneously with multiple sites, sometimes over great distances (Iraq)– PACS– Teleradiology
Myth
• “DR” will turn a bad tech into a good tech!
• TRUTH – Digital radiography makes people “stupid” = give them an “auto pilot” mentality
Myth
• “Positioning and collimation don’t matter”
• Truth: Positioning and collimation are MORE critical with digital imaging systems
Myth
• “X-ray techniques don’t matter – you can use whatever you want.”
• Truth: Images almost always look better at higher exposures – very possible to over-expose the patient!
Caveat:
• Typically use HIGHER kVp– Get the photons to the image receptor
– Algorithm to determine image quality
• STILL GREAT POTENTIAL TO OVER IRRADIATE THE PATIENT
Myth
• “DR only operates as a 200 speed system.”
• TRUTH: Can operate at whatever speed system you desire… but remember– NOISE vs. X-RAY DOSE
Myth
• “You can’t use grids with a CR system.”
• TRUTH: Grid use is still an important part of obtaining good image quality and controlling scatter
Computer Technophobia Nagy, P
• “A Symantic study found that 70% of users experienced difficulties with computers. Symptoms included swearing at computers, loss of productivity, and emotional distress. 21% of users suffer from ‘PC RAGE,’ sometimes involving physical assault on and damage of a computer.”
Skill sets NOT to forget:
• Basic Radiography 101– Proper patient positioning– Proper beam restriction– Proper exposure factors– Correct patient ID– Correct R and L marker use
Skill sets NOT to forget:
• Basic x-ray physics– How a radiographic image is made– GOOD image quality elements– Effects of incorrect x-ray exposure selection
and image quality
New Skill Set Development:
• Critical thinking skills
• Ability to identify a good image
• Knowledge of how to fix a repairable bad image
• Understanding the exposure indicator
New Terminology
• PACS– Picture Archival and Communications
Systems
• PPACS– Picture and Paper and Communications
System
New Terminology
• Teleradiology
• ASP– Application Service Providers
• DICOM– Digital Images and COmmunication in
Medicine
• HL-7– Health Level - 7
New Terminology
• HIS– Hospital Information System
• RIS– Radiology Information System
• HIS/RIS Broker (make sure they talk to each other)
21st Century Imaging
• All modalities will be in digital format
• Direct to Digital acquisition (SSXD)
• On-line access to patient records
• “Total” patient record (EMR)
• Software and equipment changes
• Radiation exposure a MAJOR concern
• Remote reading stations miles away
STOP the BS and just tell me!
• In CR – the photostimulable phosphor (just like an intensifying screen) is exposed to x-rays. The PSP cassette is then “scanned” by a laser “reader” to obtain the image (stored images are released as varied shades of “light”)
• DR/DD uses a “flat panel detector(s) and a scintillator combined with a photodiode the light produced is “digitized” and translated into “densities” for computer viewing.