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实际检查是完全无创的，没有疼痛或不适。然而，一个缺点是使用放射性物质作为显像剂来可视化癌症或与脑部疾病有关的受体系统。在脑部疾病的情况下，只有一小部分注射的显像剂到达脑部（<1%），其余的放射性物质在肝脏和肾脏等其他器官中发现，这对患者造成了不必要的辐射负担。显像剂进入大脑的运输是基于一个非常低效的过程，称为“被动扩散”，不涉及主动运输。我们打算开发新一代用于脑成像的化合物，基于将显像剂与负责将这种缀合物主动运输到大脑的“分子穿梭体”耦合的想法。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.