MRI/PET 扫描设备首次结合在一起

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MRI/PET Scanner Combo Made For First Time
ScienceDaily (Mar. 10, 2008) — Two kinds of body imaging -- positron emission tomography (PET) and magnetic resonance imaging (MRI) -- have been combined for the first time in a single scanner.

ScienceDaily (2008年3月10日) －两种人体显像设备－正电子发射型计算机断层显像（PET）和磁共振显像（MRI）－首次在一个单独的扫描设备上结合在一起了。

MRI scans provide exquisite structural detail but little functional information, while PET scans -- which follow a radioactive tracer in the body -- can show body processes but not structures, said Simon Cherry, professor and chair of biomedical engineering at UC Davis. Cherry's lab built the scanner for studies with laboratory mice, for example in cancer research.

UC戴维斯生物医学工程的主席和教授Simon Cherry说，MRI扫描可以提供精细的解剖结构的信息，不过在功能方面提供的信息就比较少；而PET扫描，可以追踪放射性示踪剂在人体的经过轨迹，从而显示人体的代谢过程，而不是解剖结构。Cherry的实验室建立了这个扫描仪，做了小鼠在肿瘤方面的研究。

\"We can correlate the structure of a tumor by MRI with the functional information from PET, and understand what's happening inside a tumor,\" Cherry said.

他说，“我们可以把MRI上面的肿瘤解剖结构方面的信息和PET得到的功能方面的信息结合起来，从而发现在肿瘤的内部正发生着什么”。

Combining the two types of scan in a single machine is difficult because the two systems interfere with each other. MRI scanners rely on very strong, very smooth magnetic fields that can easily be disturbed by metallic objects inside the scanner. At the same time, those magnetic fields can seriously affect the detectors and electronics needed for PET scanning. There is also a limited amount of space within the scanner in which to fit everything together, Cherry noted.

他说，把这两类扫描设备结合在一起是很难的，因为它们两个之间是有冲突的。MRI扫描设备需要很强的，很平稳的磁场，而这会很轻易的就被扫描设备中的金属物质给破坏了。同时，磁场也会严重影响PET扫描中的探测器和电子探测装置。同时要把这两个扫描设备很好的结合成一个设备，空间也很有限。

Scanners that combine computer-assisted tomography (CAT) and PET scans are already available, but CAT scans provide less structural detail than MRI scans, especially of soft tissue, Cherry said. They also give the patient a dose of radiation from X-rays.

Cherry说，PET和计算机辅助断层扫描（CAT）设备结合在一起的设备已经有了，不过CAT的扫描和MRI相比提供的解剖结构信息相对少一点，另外，CAT的扫描也会对病人造成一定剂量的X线辐射。

The photomultiplier tubes used in conventional PET machines are very sensitive to magnetic fields. So the researchers used a new technology -- the silicon avalanche photodiode detector -- in their machine. They were able to show that the scanner could acquire accurate PET and MRI images at the same time from test objects and mice.

在传统的PET设备上使用的光电倍增管对磁场非常的敏感。所以研究者们使用了一种新的技术－硅雪崩光电二极管探测器－在它们的新设备上。这样，这个设备就可以对测试物体和小鼠同时采集到PET和MRI的准确图像了。

The other authors on the paper, published online March 3 by the journal Proceedings of the National Academy of Sciences, are UC Davis graduate student Ciprian Catana, now at the Martinos Center for Biomedical Imaging, Harvard University; postdoctoral researcher Yibao Wu and Jinyi Qi, assistant professor of biomedical engineering, both at UC Davis; Daniel Procissi, Caltech; Bernd Pichler, University of Tübingen, Germany; and Russell Jacobs from the Beckman Institute, California Institute of Technology. Another paper by Cherry, Jacobs and UC Davis Associate Professor Angelique Louie reviewing the opportunities and challenges for combined PET/MRI was published in the Feb. 2008 issue of the Proceedings of the IEEE. The work was supported by grants from the National Institutes of Health.

Proceedings of the National Academy of Sciences杂志的3月3日的文章中的另外一个作者Ciprian Catana，是UC戴维斯的一个毕业生，现在在哈佛大学Martinos生物医学成像中心工作；Yibao Wu and Jinyi Qi两位博士后，是生物医学成像中心的助教，也是在UC戴维斯的；Daniel Procissi, Caltech; Bernd Pichler, 是德国的Tübingen大学的；Russell Jacobs是加利福尼亚技术学院Bechman学会的；Cherry和Jacobs和UC戴维斯一名助教Angelique Louie的另外一篇在IEEE进展杂志上2008年2月发表的文章，讲述了PET/MRI设备的机会和挑战。这项工作由国际健康学院资助。