Focused Collimator for Dual Modality Breast Imaging

描述(由申请人提供)： 乳房X光检查是目前乳房筛查的黄金标准。然而，阳性预测值(经乳房X光检查确定为阳性的病例中真正呈阳性的病例的比例)只有20%-25%。因此，绝大多数乳房活组织检查都是阴性的。活组织检查对许多人来说是一种非常不愉快的经历，特别是当它是假阳性的时候。弗吉尼亚大学夏洛茨维尔分校(UVA)的研究人员开发了一种新的诊断性乳房扫描仪，将数字X光乳房X光照相和核素乳房X光照相结合在一起，在普通机架上使用专用的小视场伽马相机。在核素扫描中，~(99m)Tc-Sestamibi静脉注射，并优先集中在恶性肿瘤部位。双模式扫描仪的早期临床评估显示，对于更准确的诊断，特别是对小肿块，结果是有希望的。目前的双模式扫描仪使用的是乳房X光摄影系统，该系统上安装了一个平行的孔准直仪和一个伽马相机。因此，伽马相机中的每个像素观看垂直于伽马探测器表面的射线路径，而X射线探测器中的每个像素观看聚焦在点源的射线路径。这种几何差异会产生配准误差，特别是对于肥厚的乳房和靠近乳房顶部的肿块，限制了双重成像诊断方法的全部好处。第一阶段小型企业创新计划(SBIR)提案的具体目标是：(A)为目前在UVA的系统生产小型聚焦准直器，(B)开发一种使用灵敏、成本效益高的光致抗蚀剂作为电铸模具来制造聚焦准直器的微制造方法，以及(C)评估在UVA系统上使用聚焦准直器的联合配准。第二阶段SBIR的具体目标是(A)根据第一阶段的实验数据设计改进的双模式乳房成像系统，(B)制造适合新系统的全尺寸乳房X光摄影准直器，以及(C)测试采用全尺寸准直器的双模式乳房成像系统。

DESCRIPTION (provided by applicant): Mammography is currently the gold standard for breast screening. However, the positive predictive value (fraction of cases identified as positive by mammography that truly are positive) is only 20 - 25%. Thus the vast majority of breast biopsies performed are negative. Biopsy is a very unpleasant experience for many, especially when it is a false positive. Researchers at the University of Virginia at Charlottesville (UVa) have developed a new diagnostic breast scanner by combining digital x-ray mammography and scintimammography, using a dedicated small field-of-view gamma camera, on a common gantry. In scintimammography, technetium-99m sestamibi is injected intravenously and concentrates preferentially at the site of malignant tumor. Early clinical evaluation of the dual modality scanner has shown promising results for more accurate diagnosis especially for small masses. The current dual modality scanner utilizes a mammography system, to which has been attached a parallel hole collimator and a gamma camera. Thus, each pixel in the gamma camera views a ray path perpendicular to the gamma detector surface, while each pixel in the x-ray detector views a ray path focused at the point source. This geometric discrepancy produces co-registration errors, especially for thick breasts and for masses lying near the top of the breast limiting the full benefit of the dual imaging diagnostic approach. The specific aims for this Phase I Small Business Innovation Program (SBIR) proposal are to (a) produce small focused collimators for the system currently at UVa, (b) to develop a microfabrication method using a sensitive, cost effective photoresist as the electroforming mold to fabricate the focused collimator, and (c) to evaluate co-registration using focused collimators on the UVa system. The specific aims for the Phase II SBIR are (a) to design an improved dual modality breast imaging system based on the experimental data of Phase I, (b) to fabricate a full-size mammography collimator appropriate for the new system, and (c) to test the dual modality breast imaging system incorporating the full-size collimator.