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Radiographic imaging involves the use of X-rays to capture detailed images of bones, joints, and
soft tissues. Understanding the principles behind image acquisition, positioning, and exposure
settings is essential for obtaining clear, diagnostic-quality images.

1. Principles of X-ray Imaging

X-ray imaging relies on the ability of ionizing radiation to penetrate tissues and create
diagnostic images based on varying tissue densities. Key principles include:

• X-ray Generation:
o X-rays are produced when high-energy electrons are directed at a metal target (typically
tungsten) within an X-ray tube.
o The interaction between the electrons and the target material results in the emission of X-
ray photons, which pass through the patient and create an image on a detector.
• Radiographic Density and Contrast:
o High-density tissues (e.g., bone) absorb more X-rays and appear white on the
radiograph.
o Soft tissues (e.g., muscles, ligaments) absorb less radiation and appear gray.
o Air-filled structures (e.g., lungs, sinuses) allow most X-rays to pass through and appear
black.
• Image Quality Factors:
o Kilovoltage peak (kVp): Determines the penetration power of the X-ray beam. Higher
kVp increases penetration and reduces contrast, whereas lower kVp enhances contrast but
increases radiation dose.
o Milliampere-seconds (mAs): Controls the amount of radiation used to create an image.
Higher mAs results in a brighter image but increases patient dose.
o Source-to-Image Distance (SID): The distance between the X-ray source and the
detector. A longer SID produces a sharper image with reduced distortion.
o Collimation: Restricts the X-ray beam to the area of interest, reducing patient dose and
improving image quality.
• X-ray Generation: X-rays are produced by accelerating electrons and colliding them
with a metal target inside an X-ray tube.
• Radiographic Density: Different tissues absorb X-rays at different rates, creating
contrast in the image:
o Bones appear white due to high calcium content.
o Soft tissues appear in shades of gray based on their density.
o Air-filled structures appear black (e.g., lungs or air pockets in fractures).
• Image Clarity Factors:
o Exposure settings (kVp and mAs) affect brightness and contrast.
o Patient positioning ensures correct anatomical visualization.
o Motion artifacts must be minimized through patient instruction and stabilization.

2. Standard Orthopaedic Radiographic Views

Orthopaedic X-rays must be taken in multiple planes to provide a comprehensive assessment of
bone and joint structures. Standard views vary by anatomical region and must be performed
correctly to ensure diagnostic accuracy.