What does Dual-energy X-ray Absorptiometry (DXA) not experience compared to isotope methods?

• A. Source decay
• B. Long scanning time
• C. Low precision
• D. High radiation doses

Answer: (A)

Dual-energy X-ray Absorptiometry (DXA) offers a key advantage over isotope methods by not experiencing source decay, which is a phenomenon affecting radioactive isotopes used in other imaging techniques. Isotope methods rely on the properties of radioactive materials, which can lose their effectiveness over time due to radioactive decay. As a result, the measurements can become less reliable if the isotopes are not regularly monitored and replaced.

In contrast, DXA utilizes stable X-ray sources that emit photons consistently, allowing for reliable and reproducible measurements without the worry of decay impacting the quality of the data over time. This stability ensures that DXA can provide accurate bone density measurements without the complications associated with maintaining or managing varying isotopic activity.

The other aspects mentioned, such as long scanning time, low precision, and high radiation doses, are generally more associated with other modalities or issues rather than being inherent to DXA. DXA is recognized for its relatively quick scanning times and high precision, as well as low radiation doses compared to many isotope-based imaging techniques.