Radio-Immunotherapy (RIT) Planning Using SPECT

描述（由申请人提供）： 放射免疫治疗（RIT）提供了一个机会，提供更具体的辐射到肿瘤细胞，同时保留正常组织。这种新的医疗技术使用数百万的癌症寻找抗体来引导辐射到癌症。辐射与抗体结合，伴随着它们流过血液。当抗体到达癌症部位时，它们附着并留在那里，使它们的放射性对应物有机会摧毁癌细胞。临床试验表明，RIT在治疗白血病和淋巴瘤方面是成功的，研究为在各种癌症中测试这些方法开辟了道路。RIT中使用的抗体是单克隆抗体（MAb）。在RIT计划中，MAb被修饰以结合放射性金属（例如，铟-111），其可以在核医学成像中用伽马照相机可视化。来自伽马照相机的图像显示Mab在体内定位的区域。在RIT疗法中，放射性金属被转换为钇-90，其向肿瘤提供局部辐射。在RIT计划中，共轭视图平面成像方法最广泛地用于放射性定量。然而，光子散射和叠加活动降低了平面图像的对比度。因此，活动定量的不确定性增加。最近使用CT和MRI结合平面成像的研究是令人鼓舞的，但有缺点，因为抗体的生理摄取可能不完全对应于器官或肿瘤的解剖结构。这个困难可以通过使用SPECT来克服。在这项拟议的研究中，交替透射/发射定量SPECT被建议作为平面成像的替代品。所提出的方法不会增加采集时间。假设定量SPECT在病变和器官的病变检测和剂量估计方面优于平面成像。将开发新的图像重建算法以提供定量SPECT图像。我们的假设将通过人类观察者研究和Hotelling观察者研究来验证。

DESCRIPTION (provided by applicant): Radioimmunotherapy (RIT) provides an opportunity to deliver more specific radiation to tumor cells while sparing normal tissue. This new medical technology uses millions of cancer seeking antibodies to guide radiation to the cancer. The radiation is conjoined to the antibodies, accompanying them as they flow through the bloodstream. When the antibodies arrive at the cancer site, they attach and remain there, giving their radioactive counterparts the opportunity to destroy the cancer cells. Clinical trials have shown RIT to be successful in treating leukemia and lymphoma, and studies have opened the way for testing these methods on a wide range of cancers. The antibodies used in RIT are monoclonal antibodies (MAbs). In RIT planning, the MAbs are modified to bind to radioactive metals (e.g., Indium-111), which can be visualized with a gamma camera in nuclear medicine imaging. Images from the gamma camera show areas where the Mabs localize in the body. In RIT therapy, the radioactive metal is switched to Yttrium-90, which delivers local radiation to the tumor. In RIT planning the conjugate-view planar imaging method is most widely used for radioactivity quantitation. However, photon scattering and superposition of overlying activities reduce the contrast of planar images. Uncertainty in activity quantitation therefore increases. Recent research using CT and MRI combined with planar imaging is encouraging, yet has drawbacks because the physiological uptake of antibodies may not correspond exactly to the anatomical configuration of an organ or tumor. This difficulty can be overcome by using SPECT. In this proposed research, alternating transmission/emission quantitative SPECT is suggested as a replacement for planar imaging. The proposed method will not increase acquisition time. It is hypothesized that quantitative SPECT will outperform planar imaging in terms of lesion detection and dose estimation in lesions and organs. Novel image reconstruction algorithms will be developed to provided quantitative SPECT images. Our hypothesis will be verified through human observer studies and Channelized Hotelling observer studies.