What is one notable limitation of Dual Photon Absorptiometry (DPA)?

• A. Requires a small sample size
• B. Long scan times
• C. Inability to scan soft tissue
• D. Uses radioactive isotopes

Answer: (B)

Long scan times are indeed a notable limitation of Dual Photon Absorptiometry (DPA). This technique, which uses two different energy levels of x-ray photons, can take significantly longer than other bone densitometry methods such as Dual Energy X-ray Absorptiometry (DEXA). The extended duration of scans can lead to patient discomfort and may affect the quality of the results if patients cannot remain still during the scanning process. This limitation can be particularly concerning in situations where quick assessments are necessary or in populations such as the elderly or pediatric patients, who may have difficulty remaining still for extended periods.

In comparison, other methods do not share this same level of extended scan times, which highlights one of the practical challenges associated with DPA in a clinical setting.