Which detector is typically used in a DXA machine?

• A. A-edge
• B. k-edge
• C. q-edge
• D. p-edge

Answer: (B)

In a DXA (Dual-Energy X-ray Absorptiometry) machine, the k-edge detector is commonly utilized due to its effective ability to differentiate between different types of tissues based on their density. The k-edge refers specifically to the energy level at which there is a sharp increase in the absorption of X-rays by a given material, such as calcium in bone. This characteristic is critical for accurately measuring bone mineral density.

The k-edge is specifically designed to enhance the contrast between bone and soft tissue, allowing for precise calculations of bone density, which is essential for the diagnosis and management of conditions like osteoporosis. By using specific energies of X-rays during the scanning process, DXA machines can take advantage of the k-edge to provide detailed images and quantifiable information about bone health.

This capability is foundational in bone densitometry, making the k-edge detector particularly suitable for these machines, thereby ensuring accurate assessments.