Fiber Optic Taper Research Articles

Development of EM‐CCD‐based X‐ray detector for synchrotron applications

A high speed, low noise camera system for crystallography and X-ray imaging applications is developed and successfully demonstrated. By coupling an electron-multiplying (EM)-CCD to a 3:1 fibre-optic taper and a CsI(Tl) scintillator, it was possible to detect hard X-rays. This novel approach to hard X-ray imaging takes advantage of sub-electron equivalent readout noise performance at high pixel readout frequencies of EM-CCD detectors with the increase in the imaging area that is offered through the use of a fibre-optic taper. Compared with the industry state of the art, based on CCD camera systems, a high frame rate for a full-frame readout (50 ms) and a lower readout noise (<1 electron root mean square) across a range of X-ray energies (6–18 keV) were achieved.

TH-C-19A-10: Systematic Evaluation of Photodetectors Performances for Plastic Scintillation Dosimetry

Purpose: To assess and compare the performance of different photodetectors likely to be used in a plastic scintillation detector (PSD). Methods: The PSD consists of a 1 mm diameter, 10 mm long plastic scintillation fiber (BCF-60) which is optically coupled to a clear 10 m long optical fiber of the same diameter. A light-tight plastic sheath covers both fibers and the scintillator end is sealed. The clear fiber end is connected to one of the following six studied photodetectors: two polychromatic cameras (one with an optical lens and one with a fiber optic taper replacing the lens); a monochromatic camera with the same optical lens; a PIN photodiode; an avalanche photodiode (APD); and a photomultiplier tube (PMT). Each PSD is exposed to both low energy beams (120, 180, and 220 kVp) from an orthovoltage unit, and high energy beams (6 MV and 23 MV) from a linear accelerator. Various dose rates are explored to identify the photodetectors operating ranges and accuracy. Results: For all photodetectors, the relative uncertainty remains under 5 % for dose rates over 3 mGy/s. The taper camera collects four times more signal than the optical lens camera, although its standard deviation is higher since it could not be cooled. The PIN, APD and PMT have higher sensitivity, suitable for low dose rate and out-of-field dose monitoring. PMT's relative uncertainty remains under 1 % at the lowest dose rate achievable (50 μGy/s), suggesting optimal use for live dosimetry. Conclusion: A set of 6 photodetectors have been studied over a broad dose rate range at various energies. For dose rate above 3 mGy/s, the PIN diode is the most effective photodetector in term of performance/cost ratio. For lower dose rate, such as those seen in interventional radiology, PMTs are the optimal choice. FQRNT Doctoral Research Scholarship

A scintillator-based detector with sub-100-μm spatial resolution comprising a fibre-optic taper with wavelength-shifting fibre readout for time-of-flight neutron imaging

A scintillator-based neutron-counting imaging detector with a sub-100-μm spatial resolution was developed for energy-selective neutron imaging. The detector head of the detector comprised a thin ZnS/6LiF scintillator screen, a fibre-optic taper and crossed wavelength-shifting (WLS) fibre arrays. A high spatial resolution was achieved by constructing the scintillator with a thickness of 100μm and placing it in contact with the fibre-optic taper at a magnification ratio of 3.1:1. WLS fibres with a diameter of 100±5μm (mean±SD) were specially made, and their dye content was optimized for use in crossed WLS-fibre arrays. The developed detector had a pixel size of 34μm×34μm, and exhibited spatial FWHM resolutions of 80±7μm and 61±6μm in the x and y directions, respectively. A small prototype detector demonstrated the capability of neutron imaging using Bragg edges of a Cu/Fe sample when using the pulsed-neutron source in the Materials and Life Science Experimental Facility at the Japan Proton Accelerator Research Complex.

A high-spatial-resolution fiber-optic-coupled CMOS imager with novel scintillator for high-energy x-ray applications

A fast, high-spatial-resolution detector for high-energy microscopy work is presented. The detector uses a 2160 × 2560 CMOS chip for fast framing (up to 100 Hz in full-frame mode), coupled by a fiber optic taper to a scintillating Terbium-doped fiber optic plate for excellent stopping power even at high energies. The field of view is 7mm × 8.6mm with a resolution of 9 microns. The sensitivity is 1 e-/x-ray at 35 keV, with a read noise of 2.5 e-/pixel. Standard characterization metrics including dark current, sensitivity, modulation transfer function, and detective quantum efficiency are presented, along with preliminary experimental results.

Design, Characterization, and Modeling for a Modular High-Resolution Solid-State X-Ray Image Intensifier (SSXII)

A high resolution x-ray imaging system designated the solid state x-ray image intensifier (SSXII) is being developed as a potential replacement of conventional lower-resolution x-ray detectors for neurovascular interventions. The SSXII consists of a CsI(Tl) phosphor to convert x-rays to light, a fiber optic taper to extend the field-of-view and to couple the phosphor to an Electron-Multiplying CCD (EMCCD) which has a built-in gain to boost the signal above the read-out noise floor. A parallel cascade linear-system model is explored and applied to quantitatively analyze the signal and noise transfer at each stage, and optimize the detector performance. The modulation transfer function (MTF), detective quantum efficiency (DQE) and frequency dependent instrumentation noise equivalent exposure (INEE) can be obtained from the theoretical model and experimental measurement. Agreement of these results validates the effectiveness of the model. Finally, compared with the traditional flat-panel detector (FPD), the SSXII exhibits better performance with higher spatial resolution, higher DQE and lower INEE.

Bioengineered bioluminescent magnetotactic bacteria as a powerful tool for chip-based whole-cell biosensors

This paper describes the generation of genetically engineered bioluminescent magnetotactic bacteria (BL-MTB) and their integration into a microfluidic analytical device to create a portable toxicity detection system. Magnetospirillum gryphiswaldense strain MSR-1 was bioengineered to constitutively express a red-emitting click beetle luciferase whose bioluminescent signal is directly proportional to bacterial viability. The magnetic properties of these bacteria have been exploited as "natural actuators" to transfer the cells in the chip from the reaction to the detection area, optimizing the chip's analytical performance. A robust and cost-effective biosensor for the evaluation of sample toxicity, named MAGNETOX, based on lens-free contact imaging detection, has been developed. A microfluidic chip has been fabricated using multilayered black and transparent polydimethyl siloxane (PDMS) in which BL-MTB are incubated for 30 min with the sample, then moved by microfluidics, trapped, and concentrated in detection chambers by an array of neodymium-iron-boron magnets. The chip is placed in contact with a cooled CCD via a fiber optic taper to perform quantitative bioluminescence imaging after addition of luciferin substrate. A model toxic compound (dimethyl sulfoxide, DMSO) and a bile acid (taurochenodeoxycholic acid, TCDCA) were used to investigate the analytical performance of the MAGNETOX. Incubation with DMSO and TCDCA drastically reduces the bioluminescent signal in a dose-related manner. The generation of bacteria that are both magnetic and bioluminescent combines the advantages of easy 2D cell handling with ultra sensitive detection, offering undoubted potential to develop cell-based biosensors integrated into microfluidic chips.

The point-spread function of fiber-coupled area detectors

The point-spread function (PSF) of a fiber-optic taper-coupled CCD area detector was measured over five decades of intensity using a 20 µm X-ray beam and ~2000-fold averaging. The `tails' of the PSF clearly revealed that it is neither Gaussian nor Lorentzian, but instead resembles the solid angle subtended by a pixel at a point source of light held a small distance (~27 µm) above the pixel plane. This converges to an inverse cube law far from the beam impact point. Further analysis revealed that the tails are dominated by the fiber-optic taper, with negligible contribution from the phosphor, suggesting that the PSF of all fiber-coupled CCD-type detectors is best described as a Moffat function.

SU-E-I-25: Performance Evaluation of a Proposed CMOS-Based X-Ray Detector Using Linear Cascade Model Analysis.

The need for high-resolution, dynamic x-ray imaging capability for neurovascular applications has put an ever increasing demand on x-ray detector technology. Present state-of-the-art detectors such as flat panels have limited resolution and noise performance. A linear cascade model analysis was used to estimate the theoretical performance for a proposed CMOS-based detector. The proposed CMOS-based detector was assumed to have a 300-micron thick HL type CsI phosphor, 35-micron pixels, a variable gain light image intensifier (LU), and 400 electron readout noise. The proposed detector has a CMOS sensor coupled to an LII which views the output of the CsI phosphor. For the analysis the whole imaging chain was divided into individual stages characterized by one of the basic processes (stochastic/deterministic blurring, binomial selection, quantum gain, additive noise). Standard linear cascade modeling was used for the propagation of signal and noise through the stages and an RQA5 spectrum was assumed. The gain, blurring or transmission of different stages was either measured or taken from manufacturer's specifications. The theoretically calculated MTF and DQE for the proposed detector were compared with a high-resolution, high-sensitive Micro-Angio Fluoroscope (MAF), predecessor of the proposed detector. Signal and noise for each of the 19 stages in the complete imaging chain were calculated and showed improved performance. For example, at 5 cycles/mm the MTF and DQE were 0.08 and 0.28, respectively, for the CMOS detector compared to 0.05 and 0.07 for the MAF detector. The proposed detector will have improved MTF and DQE and slimmer physical dimension due to the elimination of the large fiber-optic taper used in the MAF. Once operational, the proposed CMOS detector will serve as a further improvement over standard flat panel detectors compared to the MAF which is already receiving a very positive reception by neuro-vascular interventionalists. (Support:NIH-Grant R01EB002873) NIH Grants R01- EB008425, R01-EB002873 and an equipment grant from Toshiba Medical Systems Corp.

TU-A-218-04: Phantom Studies of a Newly Developed Solid State X-Ray Image Intensifier (SSXII) for X-Ray Image Guided Neurovascular Interventions

Purpose: X-ray image-guided interventional treatment of vascular pathology such as aneurysms involves precise delivery of devices such as stents and hence may require very high-resolution imaging capability. We report the first fluoroscopy and angiography phantom studies using a new high-resolution x-ray detector that has been developed to address this need. Methods: The Solid State X-ray Image Intensifier (SSXII) detector is based on Electron-Multiplying Charge Coupled Device (EMCCD) technology (E2V Technologies, Chelmsford, England). An EMCCD with 13- μm pixels and fiber optic window is coupled to a fiber-optic taper with a taper ratio of 3.3 that views a 300-μm thick CsI x-ray scintillator, thus making an effective pixel size of 42.9 μm and a Nyquist frequency of 11.8 lp/mm for this detector. A small aneurysm insert that was part of a flow loop was placed in the base of the brain region of an anthropomorphic head phantom (RS-230, Supertech, Elkhart, IN) to simulate pathology in the Circle of Willis of a patient and interventional procedures were done with similar attenuation and anatomical characteristics that would be experienced in the clinic. A guidewire was threaded into the aneurysm under fluoroscopic image guidance with the SSXII. Digital Subtraction Angiography (DSA) was performed using a standard contrast injection (iodine 350 mg/ml) into the flow loop and angiographic sequences were recorded with the new detector. Results: The operation of the new SSXII detector in both fluoroscopy and angiography exposure ranges was demonstrated for the first time on human phantoms. The resolution of this detector is substantially higher than current-state-of-the-art flat panel detectors with 150 to 200 μm pixels. Conclusions: The newly developed high-resolution EMCCD-based detector can potentially be used for both fluoroscopy and angiography to address the high-resolution imaging needs of x-ray image-guided neuro- vascular interventions. Supported in part by: NIH Grants R01-EB008425, R01-EB002873 and an equipment grant from Toshiba Medical Systems Corp.

A theoretical and experimental evaluation of the microangiographic fluoroscope: A high‐resolution region‐of‐interest x‐ray imager

The increasing need for better image quality and high spatial resolution for successful endovascular image-guided interventions (EIGIs) and the inherent limitations of the state-of-the-art detectors provide motivation to develop a detector system tailored to the specific, demanding requirements of neurointerventional applications. A microangiographic fluoroscope (MAF) was developed to serve as a high-resolution, region-of-interest (ROI) x-ray imaging detector in conjunction with large lower-resolution full field-of-view (FOV) state-of-the-art x-ray detectors. The newly developed MAF is an indirect x-ray imaging detector capable of providing real-time images (30 frames per second) with high-resolution, high sensitivity, no lag and low instrumentation noise. It consists of a CCD camera coupled to a Gen 2 dual-stage microchannel plate light image intensifier (LII) through a fiber-optic taper. A 300 microm thick CsI(T1) phosphor serving as the front end is coupled to the LII. The LII is the key component of the MAF and the large variable gain provided by it enables the MAF to operate as a quantum-noise-limited detector for both fluoroscopy and angiography. The linear cascade model was used to predict the theoretical performance of the MAF, and the theoretical prediction showed close agreement with experimental findings. Linear system metrics such as MTF and DQE were used to gauge the detector performance up to 10 cycles/mm. The measured zero frequency DQE(0) was 0.55 for an RQA5 spectrum. A total of 21 stages were identified for the whole imaging chain and each stage was characterized individually. The linear cascade model analysis provides insight into the imaging chain and may be useful for further development of the MAF detector. The preclinical testing of the prototype detector in animal procedures is showing encouraging results and points to the potential for significant impact on EIGIs when used in conjunction with a state-of-art flat panel detector (FPD).

TU‐C‐211‐05: A New Solid State X‐Ray Image Intensifier (SSXII) with a 1×2 Modular Array and an Acquisition, Correction, and Display System

Purpose: To provide an extended field‐of‐view (FOV) with higher resolution images, a new SSXII imager with a two‐detector modular array was built. An acquisition, correction, and display system tiles two image modules in real‐time with geometric and brightness matching at the boundary. Methods: Two fiber‐optic tapers (FOTs) were fitted together with minimum dead‐space and embedded in liquid Sylgard 184 silicone elastomer which is allowed to cure and solidify; this 1×2 FOT array was fitted into an optical “head‐box.” The EMCCD sensors were fixed to the small‐ends of the two FOTs while a single CsI x‐ray phosphor plate was fastened onto the large‐ends. The optical head‐box was then combined with custom‐built electronics boards that control the driving clocks and sample the output. The digitized frames were transmitted to a PC through a CameraLink port accommodating a rate of 30 fps for both modules simultaneously. Customized software enabled acquisition, correction (dealing with the rotational and translational misalignments between the sensors), and display of the x‐ray images in real‐time. Other functions including acquisition control, save options, temporal filters, flat‐field correction, and mode selection for fluoroscopy, roadmapping, digital angiography (DA) and digital subtraction angiography (DSA), were also implemented. Results: The processed high‐resolution image was aligned properly along the boundary. The match up error was less than 1 pixel although there was a coupling loss of just under 7% due to chamfers at the edges of the FOTs; remachining the FOTs in future versions will reduce this loss. The two aligned images from each module exhibited balanced brightness between the sensors and flat‐field correction to eliminate fixed patterns introduced by the FOTs. Conclusions: The custom‐built SSXII detector and its acquisition, correction, and display system provides higher spatial resolution and nearly seamless images for the array in real‐time. Larger arrays are planned for future SSXII implementations.Support: NIH Grants R01‐EB008425, R01‐EB002873

Depth-of-Interaction Compensation Using a Focused-Cut Scintillator for a Pinhole Gamma Camera

Preclinical SPECT offers a powerful means to understand the molecular pathways of drug interactions in animal models by discovering and testing new pharmaceuticals and therapies for potential clinical applications. A combination of high spatial resolution and sensitivity are required in order to map radiotracer uptake within small animals. Pinhole collimators have been investigated, as they offer high resolution by means of image magnification. One of the limitations of pinhole geometries is that increased magnification causes some rays to travel through the detection scintillator at steep angles, introducing parallax errors due to variable depth-of-interaction in scintillator material, especially towards the edges of the detector field of view. These parallax errors ultimately limit the resolution of pinhole preclinical SPECT systems, especially for higher energy isotopes that can easily penetrate through millimeters of scintillator material. A pixellated, focused-cut (FC) scintillator, with its pixels laser-cut so that they are collinear with incoming rays, can potentially compensate for these parallax errors and thus improve the system resolution. We performed the first experimental evaluation of a newly developed focused-cut scintillator. We scanned a Tc-99m source across the field of view of pinhole gamma camera with a continuous scintillator, a conventional "straight-cut" (SC) pixellated scintillator, and a focused-cut scintillator, each coupled to an electron-multiplying charge coupled device (EMCCD) detector by a fiber-optic taper, and compared the measured full-width half-maximum (FWHM) values. We show that the FWHMs of the focused-cut scintillator projections are comparable to the FWHMs of the thinner SC scintillator, indicating the effectiveness of the focused-cut scintillator in compensating parallax errors.

Portable Device Based on Chemiluminescence Lensless Imaging for Personalized Diagnostics through Multiplex Bioanalysis

A simple and versatile analytical device designed to perform, even simultaneously, different types of bioassays has been developed and optimized. A transparent microfluidics-based reaction chip, where analytes were quantitatively detected by means of biospecific reactions and chemiluminescence detection, was placed in contact with a thermoelectrically cooled CCD sensor through a fiber optic taper. Such a lensless contact imaging configuration combined adequate spatial resolution and high light collection efficiency within a small size portable device. The miniaturization of the reaction chamber ensured short analysis times (in the minutes range), while the use of chemiluminescence detection provided wide signal dynamic range and high detectability, down to attomole levels of protein and femtomole levels of nucleic acid analytes. A model hybrid panel test was realized by combining an enzyme assay for alkaline phosphatase activity, a nucleic acid hybridization assay for Parvovirus B19 DNA, and an immunoassay for horseradish peroxidase as a model antigen. The successful simultaneous quantification of the three targets demonstrated that a range of analytes, from enzymes to antigens, antibodies, and nucleic acids, can be measured in a single run, thus enabling the realization of a complete, personalized diagnostic panel test for early diagnosis of a given disease and patient follow-up.

A portable bioluminescence engineered cell-based biosensor for on-site applications

We have developed a portable biosensing device based on genetically engineered bioluminescent (BL) cells. Cells were immobilized on a 4 × 3 multiwell cartridge using a new biocompatible matrix that preserved their vitality. Using a fiber optic taper, the cartridge was placed in direct contact with a cooled CCD sensor to image and quantify the BL signals. Yeast and bacterial cells were engineered to express recognition elements, whose interaction with the analyte led to luciferase expression, via reporter gene technology. Three different biosensors were developed. The first detects androgenic compounds using yeast cells carrying a green-emitting P. pyralis luciferase regulated by the human androgen receptor and a red mutant of the same species as internal vitality control. The second biosensor detects two classes of compounds (androgens and estrogens) using yeast strains engineered to express green-or red-emitting mutant firefly luciferases in response to androgens or estrogens, respectively. The third biosensor detects lactose analogue isopropyl β- d-1-thiogalactopyranoside using two E. coli strains. One strain exploits the lac operon as recognition element for the expression of P. pyralis luciferase. The other strain serves as a vitality control expressing Gaussia princeps luciferase, which requires a different luciferin substrate. The immobilized cells were stable for up to 1 month. The analytes could be detected at nanomolar levels with good precision and accuracy when the specific signal was corrected using the internal vitality control. This portable device can be used for on-site multiplexed bioassays for different compound classes.

A fiber-diffraction interferometer using a coherent fiber optic taper

We present a fiber-diffraction interferometer using a coherent fiber optic taper (FOT) for optical testing in an uncontrolled environment. We use a coherent FOT and a single-mode fiber (SMF) with a thermally expanded core. Part of the measurement wave coming from a test target is condensed through an FOT and spatially filtered from an SMF to be the reference wave. Vibration of the cavity between the target and the interferometer probe is common to both reference and measurement waves. Thus the interference fringe is stabilized in an optical way. Generation of the reference wave is stable even with the target movement. The focus shift of the input measurement wave is desensitized by a coherent FOT.

A high precision recipe for correcting images distorted by a tapered fiber optic

Images captured with a tapered fiber optic camera show significant spatial distortion mainly because the spatial orientation of the fiber bundles is not identical at each end of the taper. We present three different techniques for the automatic distortion correction of images acquired with a charge-coupled device (CCD) camera bonded to a tapered optical fiber. In this paper we report — (i) comparison of various methods for distortion correction (ii) extensive quantitative analysis of the techniques and (iii) experiments carried out using a high resolution fiber optic camera. A pinhole array was used to find control points in the distorted image space. These control points were then associated with their known true coordinates. To apply geometric correction, three different approaches were investigated — global polynomial fitting, local polynomial fitting and triangulated interpolation. Sub-pixel accuracy was achieved in all approaches, but the experimental results reveal that the triangulated interpolation gave the most satisfactory result for the distortion correction. The effect of proper alignment of the mask with the fiber optic taper (FOT) camera was also investigated. It was found that the overall dewarping error is minimal when the mask is almost parallel to the CCD.

WE-E-201C-06: The Next Generation Solid State X-Ray Image Intensifier (SSXII)

Purpose: We report on new advancements with a solid state x‐ray image intensifier (SSXII) to expand the field‐of‐view (FOV) and improve detector performance. Method and Materials: The SSXII is a new high‐resolution, high‐sensitivity radiographic and fluoroscopic imager based on electron‐multiplying CCDs (EMCCDs), which views a CsI:Tl phosphor through a fiber optic taper (FOT). The SSXII has demonstrated the capabilities to significantly improve upon the inherent limitations of current state‐of‐the‐art x‐ray image intensifiers and dynamic flat panel detectors(FPD), with superior performance in terms of MTF, instrumentation noise, and DQE. To expand the FOV, a modular array has been constructed. The EMCCD camera electronics have been designed to enable a 2 × 2 abuttable array configuration. The 27 mm center‐to‐center distance enables use of 3.4:1 magnification ratio FOTs, thereby providing a FOV of 5.44 × 5.44 cm (an increase in area of 290% over the initial single module prototype). Larger arrays can be constructed. Performance of this next generation SSXII was extrapolated based on measured MTFs and transmission efficiencies of the individual components that comprise the detector.Results: Calculations indicate an averaged improvement in the MTF of a factor of 1.2 across the higher spatial‐frequency range (5 to 10 cycles/mm). X‐ray sensitivities are expected to increase by 40% due to a reduction in the FOT magnification ratio (from 4:1 to 3.4:1). The instrumentation noise equivalent exposure (INEE) was calculated to decrease from 0.2 to 0.03 μR, which is two orders of magnitude lower than present FPDs. The DQE was determined to improve by an averaged factor of 2.2 from 5 to 10 cycles/mm. Conclusions: With an expanded FOV, the SSXII is a promising candidate to replace existing state‐of‐the‐art detectors, providing improved resolution, lower instrumentation noise, and better signal‐to‐noise ratio performance. (Support: NIH Grant RO1EB008425)

MO‐E‐204C‐01: Radionuclide Imaging with a CCD‐Based, High‐Resolution X‐Ray Detector in Single Photon Counting Mode

Purpose: To demonstrate use of the high‐resolution Micro‐Angiographic Fluoroscopic (MAF) detector in single‐photon counting (SPC) mode for nuclear medicine imaging. Method and Materials: The MAF uses a CCD camera and fiber‐optic taper, has 1024 × 1024 pixels with effective pixel size of 35 microns and is capable of real‐time imaging. A 300 micron cesium iodide is coupled to a light image intensifier through a fiber optic taper. Large variable gain of the LII provides quantum‐limited operation with essentially no additive instrumentation noise and enables the MAF to operate in both energy‐integrating (EI) and the very‐sensitive low‐exposure SPC modes. To evaluate the MAF in SPC mode, a custom‐made phantom, with hot rods ranging from diameters 0.9mm to 2.3mm, filled with 1mCi of 125I was used as a test object. A medium‐energy, gamma‐camera collimator with 1‐mm diameter parallel holes was placed between the phantom and the MAF. Data was acquired at 20 fps. The collimator was used in two ways: (i) Stationary and (ii) Moving multiple times in random directions during data acquisition to blur the septal pattern with approximately the same number of counts detected per position. Each frame of the two sets was processed using two algorithms to localize events: (i) simple‐threshold and (ii) weighted‐centroid methods. The processed frames were added to give the final image. Results: (i) Stationary collimator: The image showed a grid‐like pattern corresponding to the septa walls of the collimator. All of the hot rods in the phantom can be identified, (ii) Moving collimator: The septal pattern is blurred out, and all of the rods can be clearly identified. Conclusion: The same MAF can be used in both nuclear‐medicine imaging and x‐ray imaging in SPC mode for dual‐mode imaging. Currently we are limited by collimator resolution for radionuclide imaging. Support from: NIH Grants R01EB002873 and R01EB008425.

WE-E-201C-07: The Upgraded Control, Acquisition, Processing, and Image Display System (CAPIDS) for a Micro-Angiographic Fluoroscope (MAF)

Purpose: The Control, Acquisition, Processing, and Image Display System (CAPIDS) for the Micro‐Angiographic Fluoroscope (MAF) has been upgraded and is being evaluated for hospital clinical use. Method and Materials: The CAPIDS was developed and implemented using Laboratory Virtual Instrumentation Engineering Workbench (LabVIEW) and provides a user‐friendly interface that enables control of several clinical radiographicimaging modes of the MAF, including fluoroscopy, roadmapping, radiography, and digital‐subtraction‐angiography (DSA). The MAF is a high‐resolution, high‐sensitivity, real‐time imager which consists of a 300 |im‐thick CsI phosphor, a dual‐stage micro‐channel plate light image intensifier (LII) coupled to a fiber‐optic taper (FOT), and a frame‐transfer CCD camera, providing an image matrix of 1024×1024 35‐μm square pixels with 12‐bit depth. The region‐of‐interest (ROI) MAF can be inserted in front of a standard large field‐of‐view, standard‐resolution flat‐panel‐detector (FPD) using a detector changer when higher resolution is needed during angiographic or interventional vascular imaging procedures. Several new features were added to CAPIDS including: saving DSAimages as the mask for Roadmap mode, LII gain‐drift correction, direct saving of patient images, and real‐time window/level correction. Results: The upgraded CAPIDS has been used effectively for image guidance in over 10 rabbit aneurysm creation and treatment experiments, demonstrating the system's potential benefits for future clinical use. The CAPIDS controlled MAF increases the resolution of the x‐ray image compared to a conventional FPD and thus should increase the accuracy of interventional procedures. Conclusion: The upgraded CAPIDS for the MAF was modified and used in pre‐clinical interventional experiments. This upgrade enables the CAPIDS‐MAF imaging system to perform in most common clinical x‐ray imaging modes including: fluoroscopy, roadmapping, radiography, and DSA. The system is being evaluated for adaptation into a hospital‐based clinical interventional suite. (Supported by: NIH Grants NIH Grant R01NS43924, R01‐EB002873)

SU‐GG‐I‐184: New Graphical User Interface for the Solid State X‐Ray Image Intensifier (SSXII)

Purpose: A new Graphical User Interface (GUI) was developed and implemented using Laboratory Virtual Instrumentation Engineering Workbench (LabVIEW) for a high‐resolution, high‐sensitivity SSXII, a new x‐ray detector for radiographic and fluoroscopic imaging. Method and Materials: The new SSXII consists of an array of Electron Multiplying Charge Coupled Devices (EMCCDs). EMCCDs are enhanced CCD image sensors with a unique feature that includes variable on‐chip signal amplification of up to 2000 times. These low‐noise light sensors view an x‐ray phosphor through a fiberoptic taper used to enlarge the field of view (FOV). An array of such modules has been built to further extend the FOV. The initial 1×2 array includes two identical EMCCD cameras connected to a National Instruments (NI) PCIe‐1430 dual‐channel Camera Link PC board. A new GUI was developed and implemented using LabVIEW for camera control, image acquisition, and to provide a variety of clinically‐relevant functions. Results: The GUI provides a user‐friendly interface that includes patient registration functionality and acquisition control to save 2k×1k images at a rate of 17 Hz (or faster with pixel binning). The parameter sets of each camera, including control of exposure time, trigger mode, and EMCCD gain, can be modified during imaging runs. An additional window allows the user to control all of the other camera parameters, which can be subsequently saved to a text file for reference. Initial 1×2 EMCCD camera array will be expanded to provide even larger FOVs. Conclusion: The control and acquisition capabilities provided by this GUI, along with the variable electron‐multiplication gain, high‐resolution, high‐sensitivity, and real‐time imaging capabilities of the new expanded‐FOV SSXII should provide angiographers and interventionalists with an improved ability to visualize details of small vessels and endovascular devices, making diagnoses and image‐guided interventions more accurate. (Supported by: NIH Grants R01‐EB008425, R01‐EB002873)