What organ is affected by excess aluminum in a 99mTc (MDP) preparation?

Excess aluminum in a 99mTc (MDP) preparation primarily affects the liver. When aluminum is present in radiopharmaceuticals beyond acceptable limits, it can cause toxicity, particularly in organs that are involved in detoxifying and metabolizing substances, such as the liver. The liver is responsible for processing various compounds, including metals, and is thus particularly susceptible to the harmful effects of excess aluminum.

In the context of nuclear medicine, it is vital to maintain appropriate quality control measures to ensure that radioactive preparations, such as 99mTc (MDP), meet safety standards and do not contain harmful levels of aluminum, which could compromise patient safety and the effectiveness of the imaging procedures. Monitoring aluminum content is crucial because it is known to be toxic, and a buildup can lead to adverse reactions or complications in patients. Other organs listed, like the brain, lungs, and spleen, are not the primary sites of aluminum impact in the context of 99mTc preparations, as the liver plays a more significant role in managing metal toxicity.