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Hadsell M.,University of North Carolina at Chapel Hill | Zhang J.,University of North Carolina at Chapel Hill | Laganis P.,Xinray Systems, Inc. | Sprenger F.,Xinray Systems, Inc. | And 7 more authors.
Applied Physics Letters | Year: 2013

We have developed a compact microbeam radiation therapy device using carbon nanotube cathodes to create a linear array of narrow focal line segments on a tungsten anode and a custom collimator assembly to select a slice of the resulting wedge-shaped radiation pattern. Effective focal line width was measured to be 131 μm, resulting in a microbeam width of ∼300 μm. The instantaneous dose rate was projected to be 2 Gy/s at full-power. Peak to valley dose ratio was measured to be >17 when a 1.4 mm microbeam separation was employed. Finally, multiple microbeams were delivered to a mouse with beam paths verified through histology. © 2013 AIP Publishing LLC.

Sprenger F.,Xinray Systems, Inc. | Calderon X.,University of North Carolina at Chapel Hill | Gidcumb E.,University of North Carolina at Chapel Hill | Lu J.,University of North Carolina at Chapel Hill | And 5 more authors.
Progress in Biomedical Optics and Imaging - Proceedings of SPIE | Year: 2011

Tomosynthesis requires projection images from different viewing angles. Using a distributed x-ray source this can be achieved without mechanical motion of the source with the potential for faster image acquisition speed. A distributed xray tube has been designed and manufactured specifically for breast tomosynthesis. The x-ray tube consists of 31 field emission x-ray sources with an angular range of 30°. The total dose is up to 100mAs with an energy range between 27 and 45 kVp. We discuss the source geometry and results from the characterization of the first prototype. The x-ray tube uses field emission cathodes based on carbon nanotubes (CNT) as electron source. Prior to the manufacturing of the sealed x-ray tube extensive testing on the field emission cathodes has been performed to verify the requirements for commercial tomosynthesis systems in terms of emission current, focal spot size and tube lifetime. © 2011 SPIE.

Qian X.,University of North Carolina at Chapel Hill | Tucker A.,University of North Carolina at Chapel Hill | Gidcumb E.,University of North Carolina at Chapel Hill | Shan J.,University of North Carolina at Chapel Hill | And 14 more authors.
Medical Physics | Year: 2012

Purpose: The purpose of this study is to investigate the feasibility of increasing the system spatial resolution and scanning speed of Hologic Selenia Dimensions digital breast tomosynthesis (DBT) scanner by replacing the rotating mammography x-ray tube with a specially designed carbon nanotube (CNT) x-ray source array, which generates all the projection images needed for tomosynthesis reconstruction by electronically activating individual x-ray sources without any mechanical motion. The stationary digital breast tomosynthesis (s-DBT) design aims to (i) increase the system spatial resolution by eliminating image blurring due to x-ray tube motion and (ii) reduce the scanning time. Low spatial resolution and long scanning time are the two main technical limitations of current DBT technology. Methods: A CNT x-ray source array was designed and evaluated against a set of targeted system performance parameters. Simulations were performed to determine the maximum anode heat load at the desired focal spot size and to design the electron focusing optics. Field emission current from CNT cathode was measured for an extended period of time to determine the stable life time of CNT cathode for an expected clinical operation scenario. The source array was manufactured, tested, and integrated with a Selenia scanner. An electronic control unit was developed to interface the source array with the detection system and to scan and regulate x-ray beams. The performance of the s-DBT system was evaluated using physical phantoms. Results: The spatially distributed CNT x-ray source array comprised 31 individually addressable x-ray sources covering a 30 angular span with 1 pitch and an isotropic focal spot size of 0.6 mm at full width at half-maximum. Stable operation at 28 kV(peak) anode voltage and 38 mA tube current was demonstrated with extended lifetime and good source-to-source consistency. For the standard imaging protocol of 15 views over 14, 100 mAs dose, and 2 × 2 detector binning, the projection resolution along the scanning direction increased from 4.0 cycles/mm at 10 modulation-transfer-function (MTF) in DBT to 5.1 cycles/mm in s-DBT at magnification factor of 1.08. The improvement is more pronounced for faster scanning speeds, wider angular coverage, and smaller detector pixel sizes. The scanning speed depends on the detector, the number of views, and the imaging dose. With 240 ms detector readout time, the s-DBT system scanning time is 6.3 s for a 15-view, 100 mAs scan regardless of the angular coverage. The scanning speed can be reduced to less than 4 s when detectors become faster. Initial phantom studies showed good quality reconstructed images. Conclusions: A prototype s-DBT scanner has been developed and evaluated by retrofitting the Selenia rotating gantry DBT scanner with a spatially distributed CNT x-ray source array. Preliminary results show that it improves system spatial resolution substantially by eliminating image blur due to x-ray focal spot motion. The scanner speed of s-DBT system is independent of angular coverage and can be increased with faster detector without image degration. The accelerated lifetime measurement demonstrated the long term stability of CNT x-ray source array with typical clinical operation lifetime over 3 years. © 2012 American Association of Physicists in Medicine.

Gonzales B.,Xinray Systems, Inc. | Spronk D.,Xinray Systems, Inc. | Cheng Y.,Xinray Systems, Inc. | Zhang Z.,University of Chicago | And 4 more authors.
Progress in Biomedical Optics and Imaging - Proceedings of SPIE | Year: 2013

XinRay Systems Inc has a rectangular x-ray computed tomography (CT) imaging setup using multibeam x-ray tubes. These multibeam x-ray tubes are based on cold cathodes using carbon nanotube (CNT) field emitters. Due to their unique design, a CNT x-ray tube can contain a dense array of independently controlled electron emitters which generate a linear array of x-ray focal spots. XinRay uses a set of linear CNT x-ray tubes to design and construct a stationary CT setup which achieves sufficient CT coverage from a fixed set of views. The CT system has no moving gantry, enabling it to be enclosed in a compact rectangular tunnel. The fixed locations of the x-ray focal spots were optimized through simulations. The rectangular shape creates significant variation in path length from the focal spots to the detector for different x-ray views. The shape also results in unequal x-ray coverage in the imaged space. We discuss the impact of this variation on the reconstruction. XinRay uses an iterative reconstruction algorithm to account for this unique geometry, which is implemented on a graphics processing unit (GPU). The fixed focal spots prohibit the use of an antiscatter grid. Quantitative measure of the scatter and its impact on the reconstruction will be discussed. These results represent the first known implementation of a completely stationary CT setup using CNT x-ray emitter arrays. © 2013 SPIE.

Xu X.,William Beaumont Hospital | Kim J.,William Beaumont Hospital | Kim J.,Oakland University | Laganis P.,Xinray Systems, Inc. | And 4 more authors.
Medical Physics | Year: 2011

Purpose: To demonstrate the feasibility of Tetrahedron Beam Computed Tomography (TBCT) using a carbon nanotube (CNT) multiple pixel field emission x-ray (MPFEX) tube. Methods: A multiple pixel x-ray source facilitates the creation of novel x-ray imaging modalities. In a previous publication, the authors proposed a Tetrahedron Beam Computed Tomography (TBCT) imaging system which comprises a linear source array and a linear detector array that are orthogonal to each other. TBCT is expected to reduce scatter compared with Cone Beam Computed Tomography (CBCT) and to have better detector performance. Therefore, it may produce improved image quality for image guided radiotherapy. In this study, a TBCT benchtop system has been developed with an MPFEX tube. The tube has 75 CNT cold cathodes, which generate 75 x-ray focal spots on an elongated anode, and has 4 mm pixel spacing. An in-house-developed, 5-row CT detector array using silicon photodiodes and CdWO 4 scintillators was employed in the system. Hardware and software were developed for tube control and detector data acquisition. The raw data were preprocessed for beam hardening and detector response linearity and were reconstructed with an FDK-based image reconstruction algorithm. Results: The focal spots were measured at about 1 × 2 mm 2 using a star phantom. Each cathode generates around 3 mA cathode current with 2190 V gate voltage. The benchtop system is able to perform TBCT scans with a prolonged scanning time. Images of a commercial CT phantom were successfully acquired. Conclusions: A prototype system was developed, and preliminary phantom images were successfully acquired. MPFEX is a promising x-ray source for TBCT. Further improvement of tube output is needed in order for it to be used in clinical TBCT systems. © 2011 American Association of Physicists in Medicine.

Gidcumb E.,University of North Carolina at Chapel Hill | Gao B.,Xintek, Inc. | Gao B.,Xinray Systems, Inc. | Shan J.,University of North Carolina at Chapel Hill | And 3 more authors.
Nanotechnology | Year: 2014

For imaging human breast cancer, digital breast tomosynthesis (DBT) has been shown to improve image quality and breast cancer detection in comparison to two-dimensional (2D) mammography. Current DBT systems have limited spatial resolution and lengthy scan times. Stationary DBT (s-DBT), utilizing an array of carbon nanotube (CNT) field emission x-ray sources, provides increased spatial resolution and potentially faster imaging than current DBT systems. This study presents the results of detailed evaluations of CNT cathodes for x-ray breast imaging tasks. The following were investigated: high current, long-term stability of CNT cathodes for DBT; feasibility of using CNT cathodes to perform a 2D radiograph function; and cathode performance through several years of imaging. Results show that a breast tomosynthesis system using CNT cathodes could run far beyond the experimentally tested lifetime of one to two years. CNT cathodes were found capable of producing higher currents than typical DBT would require, indicating that the s-DBT imaging time can be further reduced. The feasibility of using a single cathode of the s-DBT tube to perform 2D mammography in 4 s was demonstrated. Over the lifetime of the prototype s-DBT system, it was found that both cathode performance and transmission rate were stable and consistent. © 2014 IOP Publishing Ltd.

The present subject matter relates to inspection systems, devices and methods for x-ray inspection of objects. A conveyor can move an object to be inspected through an inspection zone along a direction of travel, one or more multibeam x-ray source arrays can provide multiple collimated x-ray beams through the inspection zone along a direction substantially perpendicular to the direction of travel, and one or more x-ray detector arrays can detect x-ray beams passing through the inspection zone from the x-ray source array. X-ray signals detected by the x-ray detector array can be recorded to form multiple x-ray projection images of the object, and the multiple x-ray projection images can be processed into three-dimensional tomographic images of the object.

Agency: Department of Health and Human Services | Branch: | Program: SBIR | Phase: Phase II | Award Amount: 1.27M | Year: 2013

Breast cancer is the most common cancer type among women. Approximately one in every eight women is diagnosed with breast cancer at some time in their life and 30% to 40% of the women who get breast cancer die. Early and accurate detection is viewed asthe best method to decrease breast cancer mortality. Therefore improving the accuracy and effectiveness of breast cancer detection has a vital value in improving women's health in US and worldwide. Mammography is an effective tool and currently widely used for early detection of breast cancer. It has played a substantial role in reducing the breast cancer mortality rate by over 20% in the last decade. However, limitations of mammography have been well publicized, such as very high false positive (70 -90%) and false negative (-30%) rates. The problem arises from the difficulty in identifying cancerous mass and Mes due to overlapping breast tissues. Today's mammography techniques rely on a pair of 2-D X-ray images of the breast, taken from two different directions: top to bottom and side to side. The breast is pulled away from the body, compressed, and held between two glass plates to ensure that the whole breast is viewed. The images are then read by a radiologist. Breast cancer, which is denser than most healthy nearby breast tissue, appears as irregular white areas. Due to the 2-D imaging nature of mammography, breast cancer structures can be hidden in the overlapping tissue and not show up on the mammogram. Digital Breast Tomosynthesis (DBT) isa 3-D imaging technique which can overcome the tissue overlap problem. It takes multiple x-ray pictures of each breast from many angles. The breast is positioned the same way it is in a conventional mammogram. In all current commercial DBT scanners, the x-ray tube moves in an arc around the breast while 11 to 25 images are taken during an 8 to 40-second examination. Then the information is sent to a computer, where it is reconstructed to produce 3-D images of the breast. DBT has the potential to revolutionize mammography by significantly reducing the tissue overlap problem inherent in conventional 2-D mammography. In principle, DBT may lead to improved sensitivity and specificity, fewer recalls, fewer biopsies, lower false alarm rates, and reducedemotional impact, and DBT is expected to become a standard screening and diagnostic tool for breast cancer in the future. PUBLIC HEALTH RELEVANCE

PubMed | University of North Carolina at Chapel Hill and Xinray Systems, Inc.
Type: Journal Article | Journal: Medical physics | Year: 2016

Microbeam radiation therapy (MRT) is a new type of cancer treatment undergoing studies at various synchrotron facilities. The principle of MRT is using arrays of microscopically small, low-energy X-radiation for the treatment of various radio-resistant, deep-seated tumors. Our motivation is to develop a compact and inexpensive image guided MRT irradiator to use in the research lab setting. After a successful initial demonstration, here we report a second generation carbon nanotube (CNT) cathode based MRT tube, capable of producing multiple microbeam lines with an anticipated dose rate of 11 Gy/min per line.The system uses multiple line CNT source arrays to generate multiple focal lines on the anode. The increase in dose-rate, compared to our first generation system, is achieved by increasing the operating voltage from 160 kVp to 225kVp, adding multiple simultaneous focal lines on the anode, and a more efficient cooling mechanism using a 6kW oil-cooled anode.This work will present the design and development process, challenges and solutions to meeting operating specifications, and the final design of the tube and collimator, along with optimization and stabilization of its use. A detailed characterization of its capabilities will be included with a comprehensive measurement of its X-ray focal line dimensions, an evaluation of its collimator alignment and microbeam dimensions, and phantom-based quantification of its dosimetric output.The development of a second generation, compact, multiple line MRT device using carbon nanotube (CNT) cathode based X-ray technology and a novel oil cooled anode design is presented here. With this new source, we are capable of delivering a total microbeam radiation dose comparable to the low end of the synchrotron based MRT systems for small animal brain tumor models.

Xinray Systems, Inc. | Date: 2010-10-26

X-ray emitters for use in x-ray devices for non-medical use for generating radiation; x-ray source devices and components for non-medical use, for inspection and security equipment, and for non-destructive product testing for industrial and scientific research applications, namely, cathodes, anodes, vacuum tubes, cooling devices for x-ray devices, and electronic controllers. X-ray emitters for use in x-ray devices for medical use for generating radiation for medical imaging and treatment; x-ray source devices and components for medical use comprised of cathodes, anodes, vacuum tubes, cooling devices for x-ray devices, and electronic controllers for medical imaging and treatment; x-ray emitters for in vivo imaging and in vivo radiation treatment. Custom manufacture and fabrication of x-ray source devices and components for use in x-ray devices for generating radiation, namely, cathodes, anodes, vacuum tubes, cooling devices, and electronic controllers.

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