Cone-beam CT with a flat-panel detector: From image science to image-guided surgery

Abstract

The development of large-area flat-panel x-ray detectors (FPDs) has spurred investigation in a spectrum of advanced medical imaging applications, including tomosynthesis and cone-beam CT (CBCT). Recent research has extended image quality metrics and theoretical models to such applications, providing a quantitative foundation for the assessment of imaging performance as well as a general framework for the design, optimization, and translation of such technologies to new applications. For example, cascaded systems models of Fourier domain metrics, such as noise-equivalent quanta (NEQ), have been extended to these modalities to describe the propagation of signal and noise through the image acquisition and reconstruction chain and to quantify the factors that govern spatial resolution, image noise, and detectability. Moreover, such models have demonstrated basic agreement with human observer performance for a broad range of imaging conditions and imaging tasks. These developments in image science have formed a foundation for the knowledgeable development and translation of CBCT to new applications in image-guided interventions - for example, CBCT implemented on a mobile surgical C-arm for intraoperative 3D imaging. The ability to acquire high-quality 3D images on demand during surgical intervention overcomes conventional limitations of surgical guidance in the context of preoperative images alone. A prototype mobile C-arm developed in academic-industry partnership demonstrates CBCT with low radiation dose, sub-mm spatial resolution, and soft-tissue visibility potentially approaching that of diagnostic CT. Integration of the 3D imaging system with real-time tracking, deformable registration, endoscopic video, and 3D visualization offers a promising addition to the surgical arsenal in interventions ranging from head-and-neck / skull base surgery to spine, orthopaedic, thoracic, and abdominal surgeries. Cadaver studies show the potential for significant boosts in surgical performance under CBCT guidance, and early clinical trials demonstrate feasibility, workflow, and image quality within the surgical theatre.

Mobile C‐arm cone‐beam CT for guidance of spine surgery: Image quality, radiation dose, and integration with interventional guidance

“…Embodiments include fixed-room C-arms, [1][2][3] mobile U-arms, 4 mobile O-arms, 5,6 and mobile C-arms. 7,8,10 The last was initially proposed for guidance of spinal surgery 9 and has since been applied to additional orthopaedic sites, 11,12 prostate brachytherapy, 13 thoracic surgery, 14 and head-and-neck=skull base surgery. [15][16][17][18] The C-arm prototype described in early work has formed a useful basis for the development of the technology (e.g., improved image quality and integration with surgical navigation systems), application in various subspecialties, and an advanced C-arm design suitable to broad clinical application.…”

Feasibility assessment of the interactive use of a Monte Carlo algorithm in treatment planning for intraoperative electron radiation therapy

“…To obtain updated patient imaging during the IOERT procedure, portable devices should be considered in the protocol (Siewerdsen 2001). Nevertheless, several challenges, which are still being studied, must be taken into account to acquire and post-process such images.…”

Image-guided intraoperative radiation therapy: current developments and future perspectives

“…In the near future, IOERT procedures would include not only accurate dose distribution planning, but also intraoperative imaging. The navigation workflow proposed [11], combined with a computed tomography study acquired during surgery using a mobile device [13], would provide all the information necessary at the time of surgery to replicate the quality assurance available in EBRT. It could seem that the availability of intraoperative computed tomography decreases the value of the tracking system but, even in that future scenario, the ability to preview the impact of the current applicator position in terms of delivered dose would be of interest.…”