Targeted radiopharmaceutical delivery to the brain

正电子发射断层扫描(PET)和单光子发射断层扫描(SPECT)是研究癌症和神经疾病(阿尔茨海默病和帕金森病)等疾病的成像手段。对于患有这些疾病的患者来说，最大的好处是使用这些机器进行的实际检查是完全非侵入性的，不涉及疼痛和不适。然而，一个缺点是使用放射性物质作为显像剂来可视化癌症或涉及脑部疾病的受体系统。对于脑部疾病，注射的显像剂只有一小部分到达大脑(1%)，其余的放射性存在于其他器官，如肝脏和肾脏，这给患者造成了不必要的辐射负担。显像剂进入大脑的传输是基于一种非常低效的过程，称为“被动扩散”，其中不涉及主动传输。我们打算开发新一代用于脑成像的化合物，其基础是将显像剂与负责将这种偶联物主动运输到大脑中的“分子穿梭”偶联。更大比例的显像剂将进入大脑，这意味着化合物的总剂量可能会减少。这最终将减少患者的辐射负担，使这些成像方法更好，也更便宜。

Positron Emission Tomography (PET) and Single Photon Emission Tomography (SPECT) are imaging modalities to investigate diseases such as cancer and neurological disorders (Alzheimer's disease and Parkinson's disease). The biggest advantage for patients suffering from these diseases is that the actual investigation using these machines is completely non-invasive, involving no pain or discomfort. One drawback however is the use of radioactive substances serving as imaging agents to visualize the cancer or the receptor system involved in brain diseases. In the case of brain diseases only a small fraction of the injected imaging agent reaches the brain (<1%) and the rest of the radioactivity is found in other organs such as liver and kidney contributing to an unwanted radiation burden for the patient. The transport of the imaging agent into the brain is based on a very inefficient process called "passive diffusion" where no active transport is involved. We intend to develop a new generation of compounds for brain imaging based on the idea of coupling the imaging agent with a "molecular shuttle" responsible for active transport of this conjugate into the brain. A greater fraction of the imaging agent would enter the brain meaning that the overall dose of the compound could be decreased. This would ultimately reduce the radiation burden for the patient making these imaging methods better and also less expensive.