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）是研究癌症和神经系统疾病（阿尔茨海默病和帕金森病）等疾病的成像方式。对于患有这些疾病的患者来说，最大的优势是使用这些机器进行的实际检查是完全无创的，不涉及疼痛或不适。然而，一个缺点是使用放射性物质作为显像剂来使癌症或涉及脑部疾病的受体系统可视化。在脑部疾病的情况下，只有一小部分注射的成像剂到达大脑（<1%），其余的放射性在其他器官如肝脏和肾脏中发现，这对患者造成了不必要的辐射负担。显像剂进入大脑的转运是基于一个非常低效的过程，称为“被动扩散”，其中不涉及主动转运。我们打算开发新一代的化合物的基础上耦合的成像剂与“分子穿梭”负责主动运输这种共轭物进入大脑的想法脑成像。更大部分的成像剂将进入大脑，这意味着化合物的总剂量可以降低。这将最终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.