What are the energy levels produced by Gadolinium-153 in DPA?

• A. 40 kev and 80 kev
• B. 44 kev and 100 kev
• C. 60 kev and 120 kev
• D. 30 kev and 70 kev

Answer: (B)

The correct choice regarding the energy levels produced by Gadolinium-153 in Dual Photon Absorptiometry (DPA) is based on the specific photon emissions that Gadolinium-153 generates during its decay process. Gadolinium-153 emits gamma radiation primarily at energy levels of approximately 44 keV and 100 keV. These energy levels are crucial for accurate bone density measurements, as they dictate the interaction of photons with the body's tissues and the subsequent resulting signals detected by the DPA system.

In the field of bone densitometry, the choice of specific energies is important because they should ideally correspond to the attenuation characteristics of bone and soft tissues. The 44 keV photon is particularly effective for measuring bone density, targeting cortical and trabecular bone effectively.

The other choices mention energy levels that do not correspond to the known emissions of Gadolinium-153. For instance, the 30 keV and 70 keV energies are not characteristic emissions of this isotope, thus they would not provide the accurate measurements needed for DPA. Similarly, the other combinations listed differ from the established emissions of Gadolinium-153, reinforcing why the 44 keV and 100 keV pair is the correct selection for density assessment