MR Image Guided Gynecologic Brachytherapy

描述（由申请人提供）：妇科癌症局限于盆腔的患者可采用放射治疗。近距离放射治疗的使用，即在外部射束辐射后将放射性种子直接放置到肿瘤中心，允许肿瘤的剂量递增，导致肿瘤的成功消退和根除。然而，在肿瘤附近，包括小肠、乙状结肠、直肠和膀胱在内的重要正常组织结构可能位于可以接受高剂量辐射的区域。在美国的大多数中心，简单的成像（X射线或CT）与剂量规定到一个单一的点是标准的护理。正常组织不是由其实际尺寸定义的，而是由近似其位置的点定义的。为了成功地确定肿瘤的位置及其与正常组织结构的关系，以便最大限度地减少对它们的剂量，有必要在近距离放射治疗施源器放置期间对骨盆进行成像。MRI比其他成像方式更精确地描绘骨盆中的肿瘤和OAR。在这项临床试验中，除了DWI MRI之外，还将研究3T T2加权MRI成像的实用性，以及图像与活检证实的癌症存在的相关性。

DESCRIPTION (provided by applicant): Patients with gynecologic cancers localized to the pelvis may be curatively treated with radiation. The use of brachytherapy, the placement of radioactive seeds directly into the center of the tumor, after external beam radiation, permits dose escalation to the tumor, resulting in successful regression and eradication of the tumor. However, adjacent to the tumor, critical normal tissue structures including the small bowel, sigmoid, rectum, and bladder may rest in regions that can receive high doses of radiation. In most centers in the U.S., simple imaging (X-ray or CT) with doses prescribed to a single point are the standard of care. Normal tissues are not defined by their actual dimensions, rather by points that approximate their location. In order to successfully determine the location of the tumor and its relationship to the normal tissues structures in order to minimize the dose to them, it is necessary to image the pelvis during brachytherapy applicator placement. MRI delineate tumor and OAR in the pelvis with much more precision than other imaging modalities. In this clinical trial, the utility of 3T T2- weighted MRI imaging, in addition to DWI MRI, and how the images correlate with biopsy-confirmed presence of cancer will be studied.