Computed & Digital Radiography
This imaging system uses a photostimulable phosphor (PSP) plate to capture image data, which is then read by a laser in a dedicated reader.
What is Computed Radiography (CR)?
This primary software processing operation adjusts image brightness and contrast by remapping raw digital pixel values using a pre-programmed standard table.
What is a Look-Up Table (LUT)?
The principle of patient-image optimization is to keep radiation doses as low as reasonably achievable while maintaining diagnostic image quality.
What is ALARA?
This interaction between x-ray photons and outer-shell electrons in tissue serves as the primary source of scatter radiation.
What is Compton scattering?
This standardized 5-digit numerical coding system maintained by the AMA is used to report medical, surgical, and diagnostic radiologic procedures for billing.
What are CPT Codes (Current Procedural Terminology)?
Digital radiography (DR) detectors are categorized into these two main operational types based on how x-rays are converted into electric signals.
What are direct and indirect conversion detectors?
This graph displays the distribution of pixel values in an image according to their frequency, serving as the basis for digital image processing.
What is a histogram?
A fundamental descriptor is defined as the smallest 2D element of a digital image array.
What is a pixel (picture element)?
A device placed between the patient and image receptor containing alternating lead strips to intercept scatter radiation.
What is a radiographic grid?
This medical classification system provides codes for diagnosing diseases, signs, symptoms, and clinical findings (historically version 9, now upgraded to version 10/11).
What is ICD (International Classification of Diseases)?
In indirect DR systems, this chemical compound component converts incident x-ray photons into visible light before it reaches the photodiode.
What is a scintillator (e.g., Cesium Iodide or Gadolinium Oxysulfide)?
In digital display devices, adjusting this window setting directly controls image contrast, while adjusting window level controls brightness.
What is window width?
This universal metric describes a digital imaging system's overall efficiency in converting input x-ray signals into a high-quality output image.
What is DQE (Detective Quantum Efficiency)?
This physical positioning technique reduces scatter reaching the image receptor by significantly increasing the Object-to-Image Distance (OID).
What is the air-gap technique?
This photometric quantity measures the total intensity of ambient light falling onto a surface, typically expressed in units of lux.
What is illuminance?
The physical area of a digital detector element responsible for capturing x-ray signal, expressed as a ratio or percentage.
What is the fill factor?
These specialized photoreceptors in the human retina are responsible for high visual acuity and daylight/photopic color perception.
What are cones?
A fundamental descriptor is defined as the smallest 2D element of a digital image array.
What is a pixel (picture element)?
An artifact created when the primary x-ray beam is improperly angled across grid lead strips, leading to undesirable density loss or striping.
What is grid cut-off?
This flat-panel display technology utilizes liquid crystals backed by semiconductor light sources to offer higher backlight stability, lower heat generation.
What is an LED-backlit LCD monitor?
This residual image phenomenon occurs in CR plates when stored energy is incompletely erased before the next exposure.
What is phantom image or ghosting?
This artifact occurs when an aggressive edge enhancement filter causes sharp, artificial optical borders or rings around high-density structures.
What is a ringing artifact (or overshoot effect)?
The specific medical imaging communication standard that governs formatting and exchange protocols for digital medical images between devices.
What is DICOM (Digital Imaging and Communications in Medicine)?
Deadlines, pixel dropouts, and detector ghosting fall under this specific classification of radiographic artifacts.
What are hardware/detector artifacts?
The physical process by which a reading monitor’s display material converts energy (such as electric current or photostimulation) into visible light to illuminate diagnostic images for a radiologist.
What is luminescence (including electroluminescence and photoluminescence)?