MRI Image Guided Radiation Therapy (IGRT) system with low cost, highly stable mag

描述（由申请人提供）：ViewRay的文艺复兴系统1000 MRI图像引导放射治疗（IGRT）系统的全面开发进展受到全球氦气日益短缺的威胁。这项开创性的技术旨在治疗腹部的癌性肿瘤，因为身体功能导致严重的器官移位，使得精确的剂量递送变得困难或不可能。液氦是目前低温铌钛（NbTi）基超导体磁体运行所必需的。在世界范围内，氦气的消耗速度超过了目前世界各地天然气井的产能（氦气是一些天然气井的副产品）。美国正在抛售战略储备以稳定油价，但收效甚微；氦的价格持续上涨。各种来源的预测都表明，在2010-2015年及以后的时间框架内，石油将出现严重短缺和价格上涨。这将威胁到所有氦气用户，尤其是核磁共振成像行业。目前，三家主要的MRI制造商已经制定了开发计划，旨在利用二硼化镁（MgB2）超导体，从再冷凝液氦浴冷却转变为干传导冷却，再转变为冷冻冷却器。Hyper Tech与这三家公司都有利用二硼化镁（MgB2）超导体的积极计划。二硼化镁超导体具有比目前使用的铌钛（NbTi）高整整30k的超导性，同时具有适用于大型磁铁制造的相同导线形式。MgB2可以实现从液氦浴冷却到传导冷却的转换，因为这种宽的温度裕度需要适应磁体中的温度梯度。即使没有氦气短缺带来的紧迫性，对所有MRI制造商来说，将其背景磁体从液氦浴冷却转变为干传导冷却也是经济有效的。在一个标准的基于NbTi的核磁共振磁体中，大约有2000升的液氦，存在着气体氦熄灭和突然释放的危险。所有现有的MRI装置都需要一个破裂盘和通往外部的大排气管道。此外，杜瓦瓶和真空外壳必须通过ASME压力容器认证，以防因破裂盘失效而产生过压。这些因素对MRI的初始价格和后续维护产生了重大的成本影响。第一阶段、第二阶段快速通道SBIR旨在消除ViewRay公司发展面临的氦气短缺障碍，同时为其商业化的Renaissance“System 1000”的单位成本提供一条显著降低的途径。在该计划中，Hyper Tech将进行必要的研究，以开发和制造使用其MgB2超导体线的无氦背景磁铁系统。我们将向viewway提供磁体系统，viewway将将其整合到他们的Renaissance system 1000 MRI IGRT系统中，并进行成像测试，以验证磁体系统与现有NbTi超导磁体成像系统的整体性能。这将导致与Hyper Tech基于MgB2的背景磁铁系统完全集成的IGRT的临床验证。

DESCRIPTION (provided by applicant): Progress toward full development of ViewRay's Renaissance" System 1000 MRI image guided radiation therapy (IGRT) system is being threatened by the growing shortage of helium worldwide. This pioneering technology is aimed at treating cancerous tumors in the abdomen where bodily functions cause significant organ displacements making precise dose delivery difficult or impossible. Liquid helium is presently essential for operation of present day low temperature niobium-titanium (NbTi) based superconductor magnets. Helium worldwide is being depleted at a rate exceeding the capacity of the current natural gas wells (helium is a byproduct of some natural gas wells) around the world. The US strategic reserves are being sold off to stabilize the price but to little avail; the price of helium continues to rise. Projections from a variety of sources all point to major shortages and the price increases in the 2010-2015 time frame and beyond. This will threaten all helium users but most of all the MRI industry. Already, the three major MRI manufacturers, have development programs aimed at converting from re-condensing liquid helium bath cooling to dry conduction cooling to cryocoolers using magnesium diboride (MgB2) superconductors. Hyper Tech has active programs with all three to utilize magnesium diboride (MgB2) superconductors. Magnesium diboride superconductors have the unique property of being superconducting a full 30 K higher than the currently used niobium titanium (NbTi) while being in the same wire form suitable for large magnet manufacturing. MgB2 enables converting from the liquid helium bath cooling to conduction cooling because of this wide temperature margin needed to accommodate temperature gradients in the magnet. Even without the urgency brought on by the helium shortage, it is cost effective to all MRI manufacturers to transition their background magnets from liquid helium bath cooling to dry conduction cooling. With an inventory of ~2000 liters of liquid helium in a standard NbTi based MRI magnet, there is the ever present danger of a quench and sudden release of gaseous helium. A rupture disc and large exhaust duct to the outside are required for all present MRI installations. In addition, the dewar and vacuum enclosure must be ASME pressure vessel certified in case of an over pressure due to a failed rupture disc. These factors make a significant cost impact on the initial price of an MRI and the follow-on maintenance. This Phase I, Phase II Fast Track SBIR endeavors to remove the helium shortage obstacle facing ViewRay's development while at the same time providing an avenue to significantly lower the unit cost of their commercialized Renaissance" System 1000. During this program Hyper Tech will perform the necessary research in order to develop and fabricate a helium free background magnet system using its MgB2 superconductor wire. We will supply the magnet system to ViewRay who will incorporate it into their Renaissance" System 1000 MRI IGRT system and perform imaging tests to verify the overall magnet system performance compared with the present NbTi superconducting magnet based imaging system. This will lead to clinical validation of the fully integrated IGRT with Hyper Tech's MgB2 based background magnet system. PUBLIC HEALTH RELEVANCE: The first true, real time MRI image guided radiation therapy (IGRT) system that delivers gamma radiation to malignant tumors with pinpoint accuracy in spite of organ movement will be demonstrated by ViewRay Renaissance" System 1000 using Hyper Tech's magnesium diboride superconducting magnets. The Hyper Tech MgB2 magnet system will significantly lower the cost and on-going maintenance costs of ViewRay's cancer treatment technology. In addition, the magnet system will be safer and less prone to quenching than presently used magnet system.