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Development of an integrated SPECT-CmT dedicated breast imaging system incorporating novel data acquisition and patient bed designs.

机译：集成了新型数据采集和病床设计的集成SPECT-CmT专用乳房成像系统的开发。

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摘要

This thesis research builds upon prior work that developed separate SPECT and CT (computed mammotomography, or breast CT) devices that were independently capable of imaging an uncompressed breast in 3D space. To further develop the system as a clinically viable device, it was necessary to integrate the separate imaging systems onto a single gantry, and to simultaneously design a patient-friendly bed that could routinely and effectively position the patient during dual-modality imaging of her uncompressed breast in the system's common field of view. This thesis describes this process and also investigates practical challenges associated with dedicated breast imaging of a prone patient using the integrated SPECT-CT device.;We initially characterized the practicability of implementing the novel x-ray beam ultra-thick K-edge filtration scheme designed for routine use with the breast CT system. Extensive computer simulations and physical measurements were performed to characterize the x-ray beam produced using K-edge filtration with cerium and to compare it to beams produced using other filtration methods and materials. The advantages of using this heavily filtered x-ray beam for uncompressed breast CT imaging were then further evaluated by measuring the dose absorbed by an uncompressed cadaver breast during the course of a routine tomographic scan. It was found that the breast CT device is indeed capable of imaging uncompressed breasts at dose levels below that of the maximum utilized for dual-view screening mammography.;To prepare the separate SPECT and CT systems for integration onto a single platform, the cross contamination of the image of one modality by primary and scattered photons of the complementary modality was quantified. It was found that contamination levels of the emission (SPECT) image by the x-ray transmission source were generally far less than 2% when using photopeak energy windows up to +/-8%. In addition, while there was some quantifiable evidence of a variation in the transmission image in response to the presence of 99mTc photons in the patient, the effect of primary and scattered 99mTc photons on the visibility of 5 mm acrylic photons in a low contrast x-ray transmission environment was negligible.;A novel, tiered, stainless steel patient bed was then designed to allow dual-modality imaging using the integrated SPECT-CT system. The performance of the hybrid SPECT-CT system was evaluated during early stage dual-modality patient imaging trials with particular emphasis placed on the performance of the patient bed. The bed was successful in its primary task of enabling dual-modality imaging of a patient's breast in the common field of view, but practical challenges to more effective patient imaging were identified as well as some novel solutions to these challenges.;In the final section of the thesis research, the feasibility of using two of these solutions was investigated with a view to imaging more of the patient's posterior breast volume. Limited angle tomographic trajectories and trajectories that involve raising or lowering the patient bed in mid tomographic acquisition were initially investigated using various geometric phantoms. A very low contrast imaging task was then tested using an observer study to quantify the effect of these trajectories on the ability of observers to maintain visibility of small geometric objects.;This initial integrated SPECT-CT imaging system has demonstrated its ability to successfully perform low dose, dual-modality imaging of the uncompressed breast. Challenges and solutions have been identified here that will make future SPECT-CT designs even more powerful and a clinically relevant technique for molecular imaging of the breast.
机译：本论文的研究基于先前的工作，该工作开发了单独的SPECT和CT（计算机X线断层扫描或乳腺CT）设备，这些设备能够独立地对3D空间中未受压的乳房进行成像。为了进一步将该系统开发为可在临床上使用的设备，有必要将单独的成像系统集成到单个龙门架上，并同时设计一个对患者友好的病床，该床可以在对患者未受压的双模式成像过程中常规有效地定位患者乳房在系统的共同视野中。本论文描述了这一过程，并研究了使用集成的SPECT-CT设备对俯卧患者进行专用乳房成像的实际挑战。我们最初对实施设计的新颖X射线束超厚K边缘过滤方案的实用性进行了表征。通常用于乳腺CT系统。进行了广泛的计算机模拟和物理测量，以表征使用K边缘过滤和铈产生的X射线束，并将其与使用其他过滤方法和材料产生的束进行比较。然后，通过在常规断层扫描过程中测量未压缩的尸体乳房吸收的剂量，进一步评估了使用这种经过严重过滤的X射线束进行未压缩乳房CT成像的优势。结果发现，乳房CT装置确实能够以低于双视点乳房X线照相所能使用的最大剂量水平对未受压的乳房进行成像。；要准备单独的SPECT和CT系统以整合到单个平台上，交叉污染通过互补模态的主光子和散射光子对一种模态的图像进行量化。已经发现，当使用高达+/- 8％的光峰能量窗时，X射线透射源对发射（SPECT）图像的污染程度通常远远小于2％。此外，虽然有一些可量化的证据表明患者中存在99mTc光子，但透射图像会发生变化，但在低对比度x-射线下，初级和散布的99mTc光子对5 mm丙烯酸光子可见度的影响光线透射的环境可以忽略不计；然后设计了一种新颖的，分层的不锈钢患者床，以使用集成的SPECT-CT系统进行双模态成像。在早期双模式患者成像试验期间评估了混合SPECT-CT系统的性能，并特别强调了患者床的性能。该床成功完成了在普通视野中对患者乳房进行双模态成像的主要任务，但确定了对更有效的患者成像的实际挑战以及针对这些挑战的一些新颖解决方案。在论文研究的基础上，研究了使用这两种解决方案的可行性，以对患者的后乳房体积进行更多成像。最初使用各种几何体模研究了有限角度断层扫描轨迹和在中层断层摄影中涉及升高或降低患者床位的轨迹。然后使用观察者研究测试了对比度很低的成像任务，以量化这些轨迹对观察者保持小几何物体可见性的能力的影响。该初始集成的SPECT-CT成像系统已经证明了其成功执行低成像的能力剂量，未受压乳房的双峰成像。此处已经确定了挑战和解决方案，这些挑战和解决方案将使未来的SPECT-CT设计变得更加强大，并且成为用于乳腺癌分子成像的临床相关技术。

著录项

  • 作者

    Crotty, Dominic Joseph.;

  • 作者单位

    Duke University.;

  • 授予单位 Duke University.;
  • 学科 Engineering Biomedical.;Health Sciences Radiology.
  • 学位 Ph.D.
  • 年度 2010
  • 页码 341 p.
  • 总页数 341
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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