• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>International Journal of Radiation Oncology, Biology, Physics >Towards integrating functional imaging in the treatment of prostate cancer with radiation: the registration of the MR spectroscopy imaging to ultrasound/CT images and its implementation in treatment planning.
【24h】

Towards integrating functional imaging in the treatment of prostate cancer with radiation: the registration of the MR spectroscopy imaging to ultrasound/CT images and its implementation in treatment planning.

机译：致力于将功能性成像与放射治疗相结合：将MR光谱成像配准到超声/ CT图像中，并将其实施在治疗计划中。

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

PURPOSE: Dose-escalation to intraprostatic tumor deposits detected by magnetic resonance spectroscopy (MRS) is an example of tumor-targeted radiation therapy. Because treatment planning for prostate brachytherapy is performed based on ultrasound (US)/computed tomography (CT) images, a sine qua non of this technique is the ability to map MRS-positive volumes (obtained in a gland deformed by the endorectal balloon coil) to the US/CT images. An empirical algorithm designed to perform this function, and its validation, are described. METHODS AND MATERIALS: Mathematically, the problem of mapping points between the MR and US/CT domains comes to: (a) ascertaining that the position of any point in the interior of the prostate is uniquely determined by the shape of the gland, and (b) finding an algorithm that describes this relationship. The image registration algorithm described here is based on the assumption that points within the gland maintain the same relative position with respect to both the axial contours of the prostate and the center of the prostate along the superior-inferior direction. Relative positions of MRS-positive voxels are calculated with this method in both MR and US/CT space. For a particular voxel in the MR space, one obtains first the z coordinate in the US/CT space, that is, along the superior-inferior direction. This determines the axial slice in the US/CT frame of reference where the other two coordinates (x, y) will be calculated. The validity of this algorithm was examined with the aid of a pelvic phantom built to simulate realistically the prostate and its surrounding bony and tissue structures and with CT scans of implanted patients obtained, at several weeks' intervals, as part of an edema-resolution study. Seventy-five "dummy" seeds were placed in the phantom, within the simulated prostate gland, in a quasi-regular pattern. The coordinates of these seeds were determined and thus served as markers of prostate deformation when an inflated rectal probe was introduced in the phantom. CT images of this phantom were taken for different volumes of the MR rectal probe and in each case the prostate outlines were contoured and seed coordinates calculated. Using these data, the predictions of the mapping algorithm could be directly verified. RESULTS: Absolute values of the 3D-positional errors in this algorithm were 2.2 mm +/- 1.2 mm (average +/- SD). Only 6 of 75 seeds had positional displacement of 4 mm or more. Similar results were obtained in the patient analysis. CONCLUSIONS: In comparison to the MRS voxel size (6.25 x 6.25 x 3.0 mm3), the present algorithm achieves the desired clinical accuracy. As well, with this 3D algorithm seed positions are reconstructed with an uncertainty that, along the z direction, is less than half the thickness of the typical US slice (0.5 cm).
机译：目的：通过磁共振波谱（MRS）检测到剂量递增至前列腺内肿瘤沉积是肿瘤靶向放射治疗的一个例子。由于前列腺近距离放射治疗的治疗计划是根据超声（US）/计算机断层扫描（CT）图像执行的，因此该技术的必要条件是能够绘制MRS阳性体积的图（在直肠内球囊线圈变形的腺体中获得）到US / CT图像。描述了设计用于执行此功能的经验算法及其验证。方法和材料：在数学上，在MR和US / CT域之间映射点的问题涉及：（a）确定前列腺内部任何点的位置都是由腺体的形状唯一确定的，并且（ b）寻找一种描述这种关系的算法。此处描述的图像配准算法基于以下假设：腺体中的点相对于前列腺的轴向轮廓和沿上下方向的前列腺中心都保持相同的相对位置。用这种方法可以在MR和US / CT空间中计算MRS阳性体素的相对位置。对于MR空间中的特定体素，首先要获得US / CT空间中的z坐标，即沿上下方向。这确定了US / CT参考系中的轴向切片，将在其中计算其他两个坐标（x，y）。借助于盆腔体模来验证该算法的有效性，该体模是为了模拟前列腺及其周围的骨和组织结构而进行的，并且作为水肿分辨率研究的一部分，每隔几周进行一次植入患者的CT扫描。将七十五个“虚拟”种子以准规则模式放置在模拟前列腺中的体模中。确定了这些种子的坐标，并在将膨胀的直肠探针引入体模中时用作前列腺变形的标志。针对不同体积的MR直肠探针拍摄该体模的CT图像，并在每种情况下绘制前列腺轮廓的轮廓并计算种子坐标。使用这些数据，可以直接验证映射算法的预测。结果：该算法中3D位置误差的绝对值为2.2 mm +/- 1.2 mm（平均值+/- SD）。 75个种子中只有6个具有4 mm或更大的位置偏移。在患者分析中获得了相似的结果。结论：与MRS体素尺寸（6.25 x 6.25 x 3.0 mm3）相比，本算法达到了所需的临床准确性。同样，使用此3D算法，种子位置的重建不确定性沿z方向小于典型美国切片的厚度（0.5厘米）的一半。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号