High specific activity radioisotopes

放射性原子或“放射性同位素”在物理学和医学上都有广泛的应用。放射性同位素不断地经历核衰变，这导致以伽马或X射线的形式发射辐射。可以使用高灵敏度的仪器来检测这些放射性物质，这些仪器可以量化低至十亿分之一毫克(10E-12克)的放射性同位素，使放射性示踪剂成为监测物理、生物或化学过程的高度敏感的手段。放射性同位素在环境科学中用于跟踪特定化学元素在生物或生态系统中随时间的吸收和分布。例如，医疗应用包括诊断成像，即使用放射性同位素来监测心脏血流，以及放射治疗，即使用更大量的特定放射性同位素来摧毁无法通过手术移除的癌细胞。

Radioactive atoms or "radioisotopes" are widely used in both the physical and medical sciences. Radioisotopes are constantly undergoing nuclear decay, which results in the emission of radiation in the form of gamma or X-rays. These can be detected using highly sensitive instruments that can quantify as little as a billionth of a milligram (10 E-12 g) of the radioisotope, rendering radioactive tracers a highly sensitive means of monitoring physical, biological or chemical processes. Radioisotopes are used in environmental sciences to follow the uptake and distribution of a particular chemical element in a biological or ecological system over time. Medical applications include diagnostic imaging, where a radioisotope is used to monitor cardiac blood flow, for example, and radiotherapy, where a larger quantity of certain radioisotopes is used to destroy cancer cells that cannot be removed surgically.