Which radioisotope is used in Dual Photon Absorptiometry?

• A. Cesium-137
• B. Gadolinium-153
• C. Strontium-90
• D. Technetium-99

Answer: (B)

Dual Photon Absorptiometry (DPA) utilizes specific radioisotopes to measure bone mineral density. Gadolinium-153 is the isotope commonly used in this technique due to its favorable properties for penetrating biological tissues and its dual-energy photon emission, which allows for the differentiation of bone from soft tissue. This capability is crucial for obtaining accurate readings of bone density, essential for diagnosing conditions like osteoporosis.

Gadolinium-153 emits photons that are ideal for the detection methods used in DPA, making it a reliable choice for assessing bone mineral content. The energies of the emitted photons are appropriately suited to be selectively absorbed by bone, providing quantitative data that can be analyzed to determine the density of bone mineralization. This is vital for clinicians aiming for precise evaluations of skeletal health.

In comparison, the other radioisotopes listed do not have the same specific application or effectiveness for this type of bone density measurement. Each has other uses in medical imaging and treatments but does not fulfill the specialized role that Gadolinium-153 plays in Dual Photon Absorptiometry.