What has replaced the isotope in Dual Photon Absorptiometry (DPA) in Dual X-ray Absorptiometry (DXA)?

• A. Another isotope
• B. X-ray tube
• C. Radioactive glucose
• D. Gamma rays

Answer: (B)

In Dual X-ray Absorptiometry (DXA), the isotope used in Dual Photon Absorptiometry (DPA) has been replaced by an X-ray tube. This transition from using isotopes to X-ray tubes represents a significant advancement in bone densitometry technology.

X-ray tubes provide a more convenient and safer option for measuring bone density compared to radioactive isotopes. They do not involve the complexities and regulatory challenges associated with handling radioactive materials. DXA utilizes low-dose X-rays to determine bone mineral density by passing X-rays through the bone and soft tissue, allowing for a quick and accurate assessment.

This change also contributes to the improved precision and reliability of bone density measurements, as well as increased patient safety and comfort, since patients are exposed to much lower levels of radiation compared to traditional DPA that relied on isotopes. Thus, the use of an X-ray tube is fundamental in enabling DXA technology to advance in both effectiveness and patient safety compared to its predecessor, DPA.