Crystal composition can stop most __________ emitted from NM pharmaceuticals

Crystal composition can stop most __________ emitted from NM pharmaceuticals

• A. Alpha particles
• B. Gamma rays
• C. Beta particles
• D. Neutrons

Answer: (B)

The main idea here is that gamma radiation is highly penetrating and requires dense, high-atomic-number materials to attenuate effectively. Nuclear medicine drugs often emit gamma photons (like the common diagnostic radiopharmaceutical technetium-99m), so shielding or crystal-based materials rich in heavy elements can absorb or scatter most of those photons. Crystals such as sodium iodide contain iodine, a high-Z element, which helps absorb gamma rays and convert their energy into detectable light in scintillation detectors. In contrast, alpha particles are quickly stopped by a sheet of paper or a few centimeters of air, beta particles by a thin layer of material, and neutrons by hydrogen-rich substances; none of these are as effective as dense crystals at stopping gamma photons. So gamma rays are the type emitted by NM pharmaceuticals that crystal-based shielding or detectors are best suited to stop.

The main idea here is that gamma radiation is highly penetrating and requires dense, high-atomic-number materials to attenuate effectively. Nuclear medicine drugs often emit gamma photons (like the common diagnostic radiopharmaceutical technetium-99m), so shielding or crystal-based materials rich in heavy elements can absorb or scatter most of those photons. Crystals such as sodium iodide contain iodine, a high-Z element, which helps absorb gamma rays and convert their energy into detectable light in scintillation detectors. In contrast, alpha particles are quickly stopped by a sheet of paper or a few centimeters of air, beta particles by a thin layer of material, and neutrons by hydrogen-rich substances; none of these are as effective as dense crystals at stopping gamma photons. So gamma rays are the type emitted by NM pharmaceuticals that crystal-based shielding or detectors are best suited to stop.