Fixed gantry tomosynthesis system for radiation therapy image guidance based on a multiple source x‐ray tube with carbon nanotube cathodes

Abstract

The authors present the design and simulation of an imaging system that employs a compact multiple source x-ray tube to produce a tomosynthesis image from a set of projections obtained at a single tube position. The electron sources within the tube are realized using cold cathode carbon nanotube technology. The primary intended application is tomosynthesis-based 3D image guidance during external beam radiation therapy. The tube, which is attached to the gantry of a medical linear accelerator (linac) immediately below the multileaf collimator, operates within the voltage range of 80-160 kVp and contains a total of 52 sources that are arranged in a rectilinear array. This configuration allows for the acquisition of tomographic projections from multiple angles without any need to rotate the linac gantry. The x-ray images are captured by the same amorphous silicon flat panel detector employed for portal imaging on contemporary linacs. The field of view (FOV) of the system corresponds to that part of the volume that is sampled by rays from all sources. The present tube and detector configuration provides an 8 x 8 cm2 FOV in the plane of the linac isocenter when the 40.96 x 40.96 cm2 imaging detector is placed 40 cm from the isocenter. Since this tomosynthesis application utilizes the extremities of the detector to record image detail relating to structures near the isocenter, simultaneous treatment and imaging is possible for most clinical cases, where the treated target is a small region close to the linac isocenter. The tomosynthesis images are reconstructed using the simultaneous iterative reconstruction technique, which is accelerated using a graphic processing unit. The authors present details of the system design as well as simulated performance of the imaging system based on reprojections of patient CT images.

Image-guided microbeam irradiation to brain tumour bearing mice using a carbon nanotube x-ray source array

“…By sequentially switching on and off the individual and spatially distributed sources, a “scanning” X-ray beam can be generated to image an object from different viewing angles without mechanical motion, which enables fast and high-resolution tomography imaging. This has been demonstrated in stationary digital tomosynthesis for imaging the breast (Qian et al 2012) and chest (Shan et al 2013), tomosynthesis-guided radiation therapy (Maltz et al 2009), and stationary computed tomography (Gonzales et al 2013). To obtain a higher X-ray flux, all or a subset of the X-ray sources can be switched on at the same time to irradiate an object from different directions.…”

Cancer nanotechnology: a new commercialization pipeline for diagnostics, imaging agents, and therapies

“…These include a high cathode operating temperature (~1000°C), which prevents miniaturization and novel source configurations that can increase imaging speed and accuracy; high imaging dose which causes radiation damage; and low temporal and spatial resolution which affects the size and accuracy of the features that can be detected. Carbon nanotube (CNT) based field emission X-ray sources have the potential to not only overcome these limitations but also enable new imaging modalities [8]. Dr. Otto Zhou's team at the University of North Carolina Center has demonstrated that the CNT X-ray technology can generate programmable pulsed X-ray waveform, at room temperature, with high temporal resolution which readily enables synchronized/gated imaging and temporal Fourier processing to increase signal/noise ratio and miniaturize X-ray source while allowing novel source configurations such as scanning multi-beam X-ray sources for dynamic and high-speed imaging.…”

Feasibility study for image reconstruction in circular digital tomosynthesis (CDTS) from limited-scan angle data based on compressed-sensing theory

“…To overcome these difficulties, Pelc et al recently revisited the circular source trajectory in DTS with an experimental system by mounting a flat-panel detector onto a mobile C-arm system [7][8][9]. In addition, Thran et al proposed a new concept of X-ray tube geometry, the so-called circular X-ray tube, which is equipped with a series of cathodes distributed around a rotating anode, enabling a circular DTS (CDTS) geometry [10].…”