Week 3: Session 6 – Radiographic Equipment and Controls

Text Explanation for Session 6

1. Differences Between Film and Digital Radiography

• Film-Based Radiography:
  In film radiography, the X-ray image is captured on a photographic film. After exposure, the film undergoes chemical processing to develop the image. While film produces high-quality images, it is time-consuming and requires physical storage space.

• Digital Radiography (DR):
  Digital radiography eliminates the need for film by capturing images directly on a digital detector. The image is immediately available for viewing, and no chemical processing is required. Digital systems allow for easier image manipulation (adjusting contrast, brightness) and electronic storage.

• Advantages of Digital Systems:
  Digital radiography provides several benefits:

  • Faster Image Availability: Images are immediately viewable, reducing patient wait time.

  • Image Manipulation: Brightness, contrast, and sharpness can be adjusted post-exposure to enhance diagnostic accuracy.

  • Electronic Storage and Sharing: Images can be stored in a PACS (Picture Archiving and Communication System) and shared electronically with other healthcare providers.

2. Image Quality Factors in Digital Imaging

• Spatial Resolution:
  This refers to the sharpness of the image and the ability to visualize small structures. Higher spatial resolution provides more detail, making it easier to identify abnormalities.

• Contrast Resolution:
  Contrast resolution refers to the ability to distinguish between different densities in the image. Digital systems generally offer better contrast resolution than film, allowing for clearer differentiation between tissues of varying density (e.g., bone vs. soft tissue).

• Noise:
  Noise refers to random variations in the image that can obscure details and reduce image quality. Reducing noise is essential for producing a clear, diagnostic image. In digital systems, noise is minimized by optimizing exposure settings and processing algorithms.

• Artifacts:
  Artifacts are unwanted features or distortions in an image that are not part of the anatomy being examined. Common digital artifacts include motion blur (caused by patient movement) and electronic interference (from faulty equipment).

3. Digital Image Post-Processing

• Brightness and Contrast Adjustment:
  After the image is captured, the technologist can adjust brightness and contrast to enhance the image. Brightness refers to the overall lightness or darkness of the image, while contrast refers to the difference between light and dark areas.

• Edge Enhancement:
  Edge enhancement is a digital processing tool that makes the edges of structures in the image more defined, improving the visualization of bones or foreign objects.

• Windowing:
  Windowing allows the technologist to adjust the range of densities displayed in the image. By manipulating the window level and width, specific structures can be emphasized, making it easier to identify abnormalities.

4. Digital Image Archiving and Sharing (PACS)

• PACS (Picture Archiving and Communication System):
  PACS is a networked system that stores, retrieves, and transmits digital images. PACS allows for the seamless sharing of radiographic images between departments and healthcare facilities. It also eliminates the need for physical film storage, as images are stored electronically and can be accessed from multiple locations.