X-ray Detector Overview | X-ray physics | Radiology Physics Course #29
X-ray Detection Systems Overview
Introduction to X-ray Detection Systems
- The discussion begins with an overview of various x-ray detection systems, emphasizing the process required to generate and analyze radiographs.
- X-ray detection systems are classified into two main categories: screen film radiography and digital radiography.
Screen Film Radiography
- Screen film radiography involves physical plastic film that displays varying optical densities, allowing different amounts of light through to create a visible image.
- This type of radiograph cannot be manipulated digitally; it is a tangible copy that must be physically handled.
Digital Radiography
- Digital radiography refers to images created in a digital format, which can be displayed on computer screens with pixel values for manipulation.
- There are two subcategories within digital radiography: computed radiography (CR) and direct digital radiography (DR).
Computed vs. Direct Digital Radiography
- Computed radiography creates a latent image in a cassette that requires manual processing into a digital image, while direct digital uses electronic signals directly from x-rays.
- Both screen film and computed systems require cassettes for image capture, whereas cassette-less systems provide immediate images digitally.
Scintillation in X-ray Detection
- Scintillation refers to converting x-ray energy into light for imaging; both indirect digital and screen film systems utilize this process.
- In contrast, computed and direct digital methods do not rely on scintillation but instead convert x-ray energy directly into electronic signals.
Fluorescence vs. Phosphorescence
- The lecture touches upon fluorescence (immediate conversion of x-rays to light) versus phosphorescence (delayed conversion), which will be explored further in relation to computed radiography.
Summary of X-ray Detection Systems
- A recap highlights multiple types of systems: screen film, computed, indirect digital using CCD or TFT arrays, and direct digital utilizing TFT arrays for immediate processing.