Chapter 16 Digital Radiography (DR) vs. Computed Radiography (CR) Flashcards
What does computed radiography (CR) use to capture x-ray images?
Photostimulable phosphor (PSP) plates.
What process releases the stored x-ray energy in a CR plate?
Laser stimulation in a CR reader.
What is the key difference between CR and DR?
CR uses imaging plates, while DR uses flat-panel detectors for immediate image capture.
What are the two types of digital radiography (DR) detectors?
- Direct detectors
- Indirect detectors
How does direct DR differ from indirect DR?
Direct DR converts x-rays directly into an electronic signal, while indirect DR first converts them into light.
What is the function of a thin-film transistor (TFT) in DR?
Stores and transmits the electrical signal to the computer for image reconstruction.
What material is commonly used in direct DR detectors?
Amorphous selenium.
What material is used in indirect DR detectors?
Cesium iodide or gadolinium oxysulfide.
What does detector quantum efficiency (DQE) measure?
How efficiently a detector converts x-rays into a usable image.
Why does digital imaging have better contrast resolution than film?
Because it can display more shades of gray due to its higher bit depth.
What is the function of flat-field correction in DR?
Removes image artifacts and ensures uniform response across the detector.
What is the purpose of automatic rescaling in DR?
Adjusts brightness and contrast to ensure consistent image quality.
What is dose creep, and why is it a concern in DR?
The gradual increase in exposure settings over time, leading to unnecessary higher patient doses.
What is the relationship between spatial resolution and pixel size in DR?
Smaller pixels = Better spatial resolution.
What does window width control in digital imaging?
Image contrast.
What does window level control?
Image brightness.
What is the main advantage of DR over CR?
Immediate image acquisition and higher DQE.
What is the function of a charged coupled device (CCD) in DR?
Converts light into an electronic signal in indirect DR systems.
How does pixel pitch affect digital image quality?
Smaller pixel pitch = Better resolution.
What is the main advantage of fixed DR systems over portable CR?
Faster workflow, lower patient dose, and better image resolution.
