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Remote patient monitoring (RPM) devices are a novel method for physicians to monitor their patients after discharge and long after they have gone home. Usually RPM devices are bulky, relatively expensive, restricted in the physiological parameters they measure and are hard to operate.MEDLINK is a low cost (~$C1500), verbally interactive, programmable and portable RPM device that possesses the ability to verbally interact with a physician to obtain his or her information as well as the patient’s key statistics, and then to obtain the physician’s selection of physiological parameters he or she wishes to remotely monitor from that particular patient. When the patient switches on the unit, MEDLINK also verbally interacts with the patient to measure and acquire the physician’s selected physiological parameter and sends this information to the physician’s phone, via text messages and emails. Security and privacy of patient’s medical data can be preserved by using the patient’s ID instead of patient name.Physiological parameters that can be acquired by MEDLINK include: ECG, blood pressure, heart rate, blood glucose, pulse rate, blood oxygen saturation, electromyography, body temperature, spirometer, respiratory rate and much more. Future work involves the integration of more biomedical sensors to the existing MEDLINK product to expand its range of measurable physiological parameters to its maximum, and to conduct a short clinical trial on the product prior to commercialisation.

Photocatalysis holds promise for inactivating environmental pathogens. Visible-light-responsive composites of carbon-doped graphitic carbon nitride and chitosan with high reactivity and processability were fabricated, and they can control pathogenic biofilms for environmental, food, biomedical, and building applications. The broad-spectrum biofilm inhibition and eradication of the photocatalytic composites against Staphylococcus epidermidis, Pseudomonas aeruginosa PAO1, and Escherichia coli O157: H7 under visible light irradiation were demonstrated. Extracellular polymeric substances in Escherichia coli O157: H7 biofilms were most resistant to photocatalytic oxidation, which led to reduced performance for biofilm removal. 1O2 produced by the composites was believed to dominate biofilm inactivation. Moreover, the composites exhibited excellent performance for inhibiting biofilm development in urine, highlighting the promise for inactivating environmental biofilms developed from multiple bacterial species. Our study provides fundamental insights into the development of new photocatalytic composites, and elucidates the mechanism of how the photocatalyst reacts with a microbiological system.

This paper investigates optical coherence tomography (OCT) as an advanced, non-invasive method for 2D and 3D imaging of the surface and subsurface morphology of glass cultural heritage. The OCT system used is a commercial ThorLabs Ganymede II spectral domain-Fourier domain system with a 930 nm center wavelength, axial resolution of 4-6 μm, and lateral resolution of 8 μm. Results from model alkali silicate glass artificially aged at 90°C and 90% RH allow distinction of real features from artifacts produced by the highly reflective glass, and serve as a basis for interpretation of deterioration phenomena. Analytical results from historical glass artifacts are focused on a group of musical glass flutes created in Paris by Claude Laurent between 1807 and 1848. OCT images are compared to results of destructive analysis of the same samples and objects by scanning electron microscopy with backscattered electron imaging of cross-sections, as well as non-invasive light microscopy and NIR fiber optic reflectance spectrometry, the latter of which yields complementary molecular information in terms of water vibrations in hydrated glass.

Background Optical coherence tomography (OCT) is a novel imaging modality that provides microstructural information of different tissue layers using near-infrared light. This prospective, multicenter phase II trial aimed to assess the accuracy of OCT-assisted cystoscopy for bladder tumor staging. Methods Patients with primary or recurrent bladder tumors (Ta,T1) identified by outpatient cystoscopy were included. The primary objective was to assess the accuracy and positive predictive value of for determining tumor stage ≥T1 correlated by histopathology. 72 suspicious lesions from 63 patients were eligible to analyze in the study. All suspected lesions were evaluated with conventional cystoscopy, interpreted in real-time using OCT, and then resected. All results were compared to pathology. A total of 363 OCT images of tumor and normal mucosa in 25 patients were obtained to evaluate diagnostic efficacy of the computer-aided texture analysis algorithm. Results Sensitivity and specificity for predicting invasive tumors (≥ T1, n = 17) were 58.8% and 92.7% for cystoscopy, 64.7% and 100% for OCT-assisted cystoscopy, respectively. Accuracy of cystoscopy and OCT-assisted cystoscopy for predicting invasive tumor was 84.7% and 91.7% (P = 0.063), respectively. Cystoscopy and OCT-assisted cystoscopy correctly predicted T stage in 52/72 and 59/72 cases, respectively (P = 0.016). Cystoscopy missed 2 more invasive tumors than OCT-assisted cystoscopy. Cystoscopy (14.3%, 1/7) and OCT-assisted cystoscopy (28.6%, 2/7) showed relatively low sensitivity in detecting muscle invasion. Computer aided texture analysis demonstrated 75.1% sensitivity, 64.0% specificity, and 74.4% accuracy for differentiating tumor and normal urothelium. Conclusion OCT-assisted cystoscopy is a real time noninvasive and simple procedure that enhanced the accuracy of staging bladder tumors and prediction of any tumor invasion. Though the study did not meet the prespecified primary endpoint, OCT imaging is a promising adjunct to cystoscopy that may supplement intraoperative decision-making during transurethral resection of bladder tumors and additional prospective studies are warranted.

Purpose: Acoustic radiation force–optical coherence elastography (ARF-OCE) systems are novel imaging systems that have the potential to simultaneously quantify and characterize the optical and mechanical properties ofin vivotissues. This article presents the construction of bladder wall phantoms for use in ARF-OCE systems. Mechanical, acoustic, and optical properties are reported and compared to published values for the urinary bladder. Methods: The phantom consisted of 0.2000 ± 0.0089 and 6.0000 ± 0.2830 μ m polystyrene microspheres (Polysciences Inc., Warrington, PA, Catalog Nos. 07304 and 07312), 7.5 ± 1.5 μ m copolymer microspheres composed of acrylonitrile and vinylidene chloride, (Expancel, Duluth, GA, Catalog No. 461 DU 20), and bovine serum albumin within a gelatin matrix. Young’s modulus was measured by successive compression of the phantom and obtaining the slope of the resulting force-displacement data. Acoustic measurements were performed using the transmission method. The phantoms were submerged in a water bath and placed between transmitting and receiving 13 mm diameter unfocused transducers operating at a frequency of 3.5 MHz. A MATLAB algorithm to extract the optical scattering coefficient from optical coherence tomography(OCT)images of the phantom was used. Results: The phantoms possess a Young’s modulus of 17.12 ± 2.72 kPa , a mass density of 1.05 ± 0.02 g / cm 3 , an acoustic attenuation coefficient of 0.66 ± 0.08 dB / cm / MHz , a speed of sound of 1591 ± 8.76 m / s , and an optical scattering coefficient of 1.80 ± 0.23 mm − 1 . Ultrasound and OCTimages of the bladder wall phantom are presented. Conclusions: A material that mimics the mechanical, optical, and acoustic properties of healthy bladder wall has been developed. This tissue-mimicking bladder wall phantom was developed as a control tool to investigate the feasibility of using ARF-OCE to detect the mechanical and optical changes that may be indicative of the onset or development of cancer in the urinary bladder. By following the methods used in this article, phantoms matching the optical, acoustic, and mechanical properties of other biological tissues can also be constructed.

Optical coherence tomography (OCT) is a new modality that allows noninvasive examination of the internal structure of biological tissue in vivo with a spatial resolution of 10 to 15 microm. This study evaluated the clinical application of OCT to determine epithelial and subepithelial anatomic structure and invasiveness of bladder epithelial lesions.The OCT examination was performed with a 980-nm 10 mW superluminescent diode using a 2.7-mm-diameter optical fiber positioned cystoscopically. A total of 261 scans of 1.5 seconds' duration, which generated 200 x 200-pixel images, were performed on 87 areas in 24 patients at high risk of having transitional-cell carcinoma (TCC). Lesions, visually suspect, and normal areas were photographed, scanned, and biopsied. The scans were evaluated independently before comparison with histopathology findings.Of the 87 areas, 29 of 36 visually suspect areas and 35 of 35 normal areas, were correctly diagnosed with OCT. Of the 16 areas with papillary TCC, all 16 were diagnosed correctly as tumor, and 9 of 10 were diagnosed correctly as invasive, including 6 with lamina propria invasion only. Papillary and flat tumors, carcinoma in situ, inflammation, chronic cystitis, and von Brunn's nests were scanned. Overall, OCT had a sensitivity of 100%, overall specificity of 89%, positive predictive value of 75%, and negative predictive value of 100%. The accuracy was 92%. The positive predictive value for invasion was 90%.Optical coherence tomography is a simple, portable, promising modality for evaluation of bladder lesions and depth of tumor penetration. Further refinement of this technology may lead to the development of an optical surrogate for biopsy.

Optical scanners have numerous applications from bar code readers and laser printers in industry to corneal resurfacing and optical coherence tomography in medicine. We have developed an optical scanner fabricated using photolithography on a polyimide substrate. This scanner uses an electrostatic microelectromechanical system (MEMS) actuator to tilt a gold-coated mirror resting on 3 μm thick polyimide torsion hinges to steer an optical beam. The linear actuator used is the integrated force array (IFA), a network of hundreds of thousands of deformable capacitors, which electrostatically contract with an applied differential voltage. IFAs are 2.2 μm thick patterned, metallized polyimide films 1 cm long and either 1 or 3 mm wide depending on the application. The mirror support structures were modeled using one-dimensional beam theory and ANSYS finite element analysis and then fabricated using a three-layer process with polyimide and gold on silicon wafers. Side scanning structures have been fabricated with tables 1.125 or 2.25 mm wide. The completed devices were coated with a 500 A thick conformal coating of parylene for protection from the environment. These devices have demonstrated optical scan angles up to 146° for applied voltages up to ±50 V. These devices were also used to steer a laser beam in a prototype bar code reader to demonstrate functionality.

Catheter-based intracardiac ultrasound offers the potential for improved guidance of interventional cardiac procedures. The objective of this research is the development of catheter-based mechanical sector scanners incorporating high frequency ultrasound transducers operating at frequencies up to 20 MHz. The authors' current transducer assembly consists of a single 1.75 mm by 1.75 mm, 20 MHz, PZT element mounted on a 2 mm by 2 mm square, 75 /spl mu/m thick polyimide table that pivots on 3-/spl mu/m thick gold plated polyimide hinges. The hinges also serve as the electrical connections to the transducer. This table-mounted transducer is tilted using a miniature linear actuator to produce a sector scan. This linear actuator is an integrated force array (IFA), which is an example of a micromachine, i.e., a microelectromechanical system (MEMS). The IFA is a thin (2.2 /spl mu/m) polyimide membrane, which consists of a network of hundreds of thousands of micron scale deformable capacitors made from pairs of metallized polyimide plates. IFAs contract with an applied voltage of 30-120 V and have been shown to produce strains as large as 20% and forces of up to 8 dynes. The prototype transducer and actuator assembly was fabricated and interfaced with a GagePCI analog to digital conversion board digitizing 12 bit samples at a rate of 100 MSamples/second housed in a personal computer to create a single channel ultrasound scanner. The deflection of the table transducer in a low viscosity insulating fluid (HFE 7100, 3M) is up to /spl plusmn/10/spl deg/ at scan rates of 10-60 Hz. Software has been developed to produce real-time sector scans on the PC monitor.

A total laryngectomy removes the vocal folds which are fundamental in forming voiced sounds that make speech possible. Although implanted prosthetics are commonly used in developed countries, simple handheld vibrating electrolarynxes are still common worldwide. These devices are easy to use but suffer from many drawbacks including dedication of a hand, mechanical sounding voice, and sound leakage. To address some of these drawbacks, we introduce a novel electrolarynx that uses vibro-acoustic interference of dual ultrasonic waves to generate an audible fundamental frequency. A 3D simulation of the principles of the device is presented in this paper.

Optical/acoustic radiation imaging (OARI) is a novel imaging modality being developed to interrogate the optical and mechanical properties of soft tissues. OARI uses acoustic radiation force to generate displacement in soft tissue. Optical images before and after the application of the force are used to generate displacement maps that provide information about the mechanical properties of the tissue under interrogation. Since the images are optical images, they also represent the optical properties of the tissue as well. In this paper, the authors present the first imaging probe that uses acoustic radiation force in conjunction with optical coherence tomography (OCT) to provide information about the optical and mechanical properties of tissues to assist in the diagnosis and staging of epithelial cancers, and in particular bladder cancer.The OARI prototype probe consisted of an OCT probe encased in a plastic sheath, a miniaturized transducer glued to a plastic holder, both of which were encased in a 10 cm stainless steel tube with an inner diameter of 10 mm. The transducer delivered an acoustic intensity of 18 W/cm(2) and the OCT probe had a spatial resolution of approximately 10-20 μm. The tube was filled with deionized water for acoustic coupling and covered by a low density polyethylene cap. The OARI probe was characterized and tested on bladder wall phantoms. The phantoms possessed Young's moduli ranging from 10.2 to 12 kPa, mass density of 1.05 g/cm(3), acoustic attenuation coefficient of 0.66 dB/cm MHz, speed of sound of 1591 m/s, and optical scattering coefficient of 1.80 mm(-1). Finite element model (FEM) theoretical simulations were performed to assess the performance of the OARI probe.The authors obtained displacements of 9.4, 8.7, and 3.4 μm for the 3%, 4%, and 5% bladder wall phantoms, respectively. This shows that the probe is capable of generating optical images, and also has the ability to generate and track displacements in tissue. This will provide information about the optical and mechanical properties of the tissue to assist in epithelial cancer detection. The corresponding theoretical FEM displacement was 5.8, 5.4, and 5.0 μm for the 3%, 4%, and 5% phantoms, respectively. Deviation between OARI displacement and FEM displacement is due to the resolution of the crosscorrelation algorithm used to track the displacement. To the authors' knowledge, this is the first probe that successfully combines OCT with a source of acoustic radiation force.The OARI probe has the ability to provide information about the mechanical and optical properties of phantoms and soft tissue. This could prove useful in early epithelial cancer detection. Because the probe is 10 mm in diameter, it is currently only useful for skin and oral applications. The probe would have to be reduced in size to make it applicable for cancer detection in other internal sites. Future work will focus on utilizing phase-sensitive optical coherence elastography to obtain the resulting OARI displacements, improving the resolution of the probe, and enable physicians to better evaluate the mechanical properties of soft tissues.

The extraction of the brain from the skull in medical images is a necessary first step before image registration or segmentation. While pre-clinical MR imaging studies on small animals, such as rats, are increasing, fully automatic imaging processing techniques specific to small animal studies remain lacking. In this paper, we present an automatic rat brain extraction method, the Rat Brain Deformable model method (RBD), which adapts the popular human brain extraction tool (BET) through the incorporation of information on the brain geometry and MR image characteristics of the rat brain. The robustness of the method was demonstrated on T2-weighted MR images of 64 rats and compared with other brain extraction methods (BET, PCNN, PCNN-3D). The results demonstrate that RBD reliably extracts the rat brain with high accuracy (>92% volume overlap) and is robust against signal inhomogeneity in the images.

Acoustic radiation force-optical coherence elastography (ARF-OCE) systems are novel imaging systems that have the potential to simultaneously quantify and characterize the optical and mechanical properties of in vivo tissues. This article presents the construction of bladder wall phantoms for use in ARF-OCE systems. Mechanical, acoustic, and optical properties are reported and compared to published values for the urinary bladder.The phantom consisted of 0.2000 +/- 0.0089 and 6.0000 +/- 0.2830 microm polystyrene microspheres (Polysciences Inc., Warrington, PA, Catalog Nos. 07304 and 07312), 7.5 +/- 1.5 microm copolymer microspheres composed of acrylonitrile and vinylidene chloride, (Expancel, Duluth, GA, Catalog No. 461 DU 20), and bovine serum albumin within a gelatin matrix. Young's modulus was measured by successive compression of the phantom and obtaining the slope of the resulting force-displacement data. Acoustic measurements were performed using the transmission method. The phantoms were submerged in a water bath and placed between transmitting and receiving 13 mm diameter unfocused transducers operating at a frequency of 3.5 MHz. A MATLAB algorithm to extract the optical scattering coefficient from optical coherence tomography (OCT) images of the phantom was used.The phantoms possess a Young's modulus of 17.12 +/- 2.72 kPa, a mass density of 1.05 +/- 0.02 g/cm3, an acoustic attenuation coefficient of 0.66 +/- 0.08 dB/cm/MHz, a speed of sound of 1591 +/- 8.76 m/s, and an optical scattering coefficient of 1.80 +/- 0.23 mm(-1). Ultrasound and OCT images of the bladder wall phantom are presented.A material that mimics the mechanical, optical, and acoustic properties of healthy bladder wall has been developed. This tissue-mimicking bladder wall phantom was developed as a control tool to investigate the feasibility of using ARF-OCE to detect the mechanical and optical changes that may be indicative of the onset or development of cancer in the urinary bladder. By following the methods used in this article, phantoms matching the optical, acoustic, and mechanical properties of other biological tissues can also be constructed.

This paper describes the development of novel computer-aided analysis algorithms to identify the language activation patterns at a certain Region of Interest (ROI) in Functional Magnetic Resonance Imaging (fMRI). Previous analysis techniques have been used to compare typical and pathologic activation patterns in fMRI images resulting from identical tasks but none of them analyzed activation topographically in a quantitative manner. This paper presents new analysis techniques and algorithms capable of identifying a pattern of language activation associated with localization related epilepsy. fMRI images of 64 healthy individuals and 31 patients with localization related epilepsy have been studied and analyzed on an ROI basis. All subjects are right handed with normal MRI scans and have been classified into three age groups (4-6, 7-9, 10-12 years). Our initial efforts have focused on investigating activation in the Left Inferior Frontal Gyrus (LIFG). A number of volumetric features have been extracted from the data. The LIFG has been cut into slices and the activation has been investigated topographically on a slice by slice basis. Overall, a total of 809 features have been extracted, and correlation analysis was applied to eliminate highly correlated features. Principal Component analysis was then applied to account only for major components in the data and One-Way Analysis of Variance (ANOVA) has been applied to test for significantly different features between normal and patient groups. Twenty Nine features have were found to be significantly different (p

Texture analysis for tissue characterization is a current area of optical coherence tomography (OCT) research. We discuss some of the differences between OCT systems and the effects those differences have on the resulting images and subsequent image analysis. In addition, as an example, two algorithms for the automatic recognition of bladder cancer are compared: one that was developed on a single system with no consideration for system differences, and one that was developed to address the issues associated with system differences. The first algorithm had a sensitivity of 73% and specificity of 69% when tested using leave-one-out cross-validation on data taken from a single system. When tested on images from another system with a different central wavelength, however, the method classified all images as cancerous regardless of the true pathology. By contrast, with the use of wavelet analysis and the removal of system-dependent features, the second algorithm reported sensitivity and specificity values of 87 and 58%, respectively, when trained on images taken with one imaging system and tested on images taken with another.

The vast majority of bladder cancers originate within 600 m of the tissue surface, making optical coherence tomography OCT a potentially powerful tool for recognizing cancers that are not easily visible with current techniques. OCT is a new technology, how- ever, and surgeons are not familiar with the resulting images. Technol- ogy able to analyze and provide diagnoses based on OCT images would improve the clinical utility of OCT systems. We present an automated algorithm that uses texture analysis to detect bladder can- cer from OCT images. Our algorithm was applied to 182 OCT images of bladder tissue, taken from 68 distinct areas and 21 patients, to classify the images as noncancerous, dysplasia, carcinoma in situ CIS, or papillary lesions, and to determine tumor invasion. The re- sults, when compared with the corresponding pathology, indicate that the algorithm is effective at differentiating cancerous from noncancer- ous tissue with a sensitivity of 92% and a specificity of 62%. With further research to improve discrimination between cancer types and recognition of false positives, it may be possible to use OCT to guide endoscopic biopsies toward tissue likely to contain cancer and to avoid unnecessary biopsies of normal tissue. © 2008 Society of Photo-Optical

This paper provides an overview of recent research in the use of microelectromechanical systems (MEMS) actuators for beam steering applications, including optical coherence tomography (OCT). Prototype scanning devices have been fabricated out of polyimide substrates using conventional integrated circuit technology. The devices utilize piezoelectric bimorphs to mechanically actuate the torsion mirror structure made of polyimide. The material properties of the polyimide allow very large scan angles to be realized in the devices while using low voltages. Prototype devices have demonstrated optical scan angles of over 80 degrees with applied voltages of only 40V. Different device sizes have also been demonstrated with resonant frequencies between 15-60Hz (appropriate for real-time imaging). Analytical models have been developed that predict resonant frequency of the device as well as the angular displacement of the mirror. Further finite element modeling (FEM) has been done using ANSYS. These models closely reflect measured scan angles of the prototype devices. Based upon these models, further refinements can be made to the design to produce specific resonant frequencies for use in a multitude of applications. These models are currently being used to design and fabricate multiple devices on a single wafer with minimal post processing requirements. The ability to fabricate these devices in bulk will reduce their cost and potentially make them disposable to reduce the cost of their use in numerous applications, including patient care when used in biomedical imaging applications.

We have modeled, fabricated, and tested polyimide amplified piezoelectric bimorph scanning mirrors for application in optical coherence tomography (OCT). These scanning mirrors are fabricated using photolithography using polyimide as a substrate. These devices use bimorph actuators to drive polyimide micromechanical structures at resonance. The forced vibration of these micromechanical structures causes polysilicon gold plated mirrors attached to two torsion hinges to tilt. Operating the device at resonance allows us to achieve very large displacements of the mirror at real-time imaging speeds. The large scan angles and fast imaging speeds give these novel scanning devices the potential to be used to image larger areas of tissue to search for diseases such as mucosal cancers and to guide interventional procedures such as laser ablations and biopsies in real time. The mirror and support structures were modeled using one-dimensional beam theory and fundamental vibration mechanics. The structures were also modeled and simulated using ANSYS, a finite element analysis package. The finite element modeling has also lead to the development of new methods to fabricate the entire devices on a single silicon wafer. Prototype scanning devices have demonstrated optical scan angles up to 97 degrees with applied voltages from 15-60 V at a resonant frequencies ranging from 12-60 Hz, appropriate for real time imaging. These amplified bimorph imaging probes have been integrated into the scanning arm of a Spectral Domain OCT (SD-OCT) imaging system and have been used to generate preliminary in vivo human skin images at frame rates of 25 frames per second.

We have modeled, fabricated, and tested an amplified bimorph scanning mirror for application in optical coherence tomography. The scanning mirror was fabricated using photolithography on a polyimide substrate. This scanning mirror uses a bimorph actuator to drive a polyimide micromechanical structure at resonance. The forced vibration of the micromechanical structure causes a polysilicon gold plated mirror attached to two torsion hinges to tilt. Operating the device at resonance allows us to achieve very large displacements of the mirror. The material properties of the polyimide allow for large torsion angles in the hinges to be realized. The mirror and support structures were modeled using one-dimensional beam theory and fundamental vibration mechanics. The structures were also modeled and simulated using Intellisuite, a microelectromechanical (MEMS) analysis package. This device has demonstrated optical scan angles of up to 80 degrees using applied voltages of 35 V at resonant frequencies of 35 Hz, appropriate for real time imaging.

Endoscopic optical coherence tomography (EOCT) is a medical imaging technique that uses infrared light delivered via an endoscope to produce high-resolution images of tissue microstructure of the gastrointestinal tract. A key component of an EOCT system is the method used to scan the infrared beam across the tissue surface. We have begun developing electrostatic MEMS micromirror devices for use in EOCT. These devices consist of 1 mm square gold-plated silicon mirrors on polyimide tables that tilt on 3 micron thick torsion hinges. The MEMS actuator used to tilt the mirror, the integrated forces array (IFA) is a thin (2.2 μm) polyimide membrane consisting of hundreds of thousands of deformable capacitors that can produce strains up to 20% and forces equivalent to 13 mg with applied voltages from 30-120 V. Measurements of optical deflections of these devices range from 18° at low frequencies to more than 120° near the resonant frequencies of the structures (30-60 Hz). The support structures, hinges, and actuators are fabricated from polyimide on silicon using photolithography. These electrostatic MEMS micromirrors were inserted into the scanning arm of an OCT imaging system to take in vitro images of porcine tissue and in vivo images of human skin at frame rates from 4-8 Hz. SLA probe tips were designed and fabricated to align the optics of the device and to protect the fragile polyimide devices during endoscopic imaging. In addition, devices are being fabricated that combine the IFA and mirror structures onto a single silicon wafer, reducing fabrication difficulty.

Catheter based intracardiac ultrasound offers the potential for improved guidance of interventional cardiac procedures. The objective of this work is the development of catheter based, forward-looking mechanical sector scanners incorporating high frequency ultrasound transducers operating at frequencies up to 20 MHz. The current transducer assembly consists of a single 20 MHz PZT piston mounted on a polyimide table that pivots on gold plated polyimide hinges. This table-mounted transducer is tilted using a linear MEMS actuator to produce a sector scan. The prototype transducer/actuator assembly was fabricated and interfaced with a personal computer to create a single channel ultrasound scanner. This paper discusses the development of and results obtained by this real time scanning system.

We have previously described a hand crafted prototype intracardiac scanner that consists of a single high frequency PZT piston transducer that is mechanically steered by a micromachine (MEMS) actuator to produce a sector scan. More recently, we have improved the mechanical sector scanner design using finite element analysis and integrated circuit fabrication. Our new devices were designed using ANSYS finite element software to maximize the sector scan angle for the forces produced by the linear actuator, the integrated force array (IFA). These new devices are fabricated on silicon wafers using conventional integrated circuit technology. The designs include both a forward looking hinged table similar to the previous prototypes and a new side viewing device that has a transducer table tilting on miniature torsion hinges. In this paper we will present results from the design, fabrication, and testing of these new devices.

A sol gel process has been used to develop a 30 /spl mu/m thick PZT coating on a sapphire wafer. The sol gel film was removed and plated with platinum electrodes. The free-standing film had a free dielectric constant (/spl epsiv//sup T/) of 820, a thickness-mode coupling coefficient (k/sub t/) of 0.17, a speed of sound (c) of 3700 m/s, and an acoustic impedance (Z) of 28.9 MRayls. The film resonated at 62 MHz. These results were similar to KLM simulation results. A sol gel transducer was built by first backing the film with 2.2 mm thick silver epoxy. The transducer resonated at 32, 64, and 92 MHz. At 32 MHz, the transducer had a bandwidth of 40%. The insertion loss at 47 MHz was -66 dB. A 32 MHz image was constructed with this transducer by off-line processing of 40 rf-lines of data.

In this paper we describe two new types of transducer assemblies fabricated from polyimide films with photolithography that use a polyimide micromachine (MEMS) actuator to mechanically scan an ultrasound beam. Forward viewing transducers pivoting on cantilever hinges and side scanning transducers tilting on torsion hinges were fabricated on polyimide substrates with tables 1.125 mm and 2.25 mm wide. PZT transducers fabricated on these tables operating at 20 MHz and 30 MHz yielded insertion losses of 20-26 dB and fractional bandwidths of 34-49%. The transducer assemblies driven by MEMS actuators produced sector scans of 45-60 degrees in air at resonant frequencies of 32 to 90 Hz and sector scans in fluid of 6-8 degrees. Real time images of wire phantoms were obtained using a single channel imaging system based on a personal computer platform with LabVIEW (National Instruments Corp., Austin, TX) software.

There is much interest in the biomedical community in mechanically steering both high frequency ultrasound transducers and various optical beams. We are currently investigating the use of two different types of MEMS actuators, integrated force arrays (IFAs) and spiral wound transducers (SWTs). The IFA is a linear actuator that is a parallel network of hundreds of thousands of flexible capacitors that electrostatically contract, and the SWT is a patterned tape that is wound to form a circular network of flexible capacitors that can be electrostatically compressed to tilt desired structures. Using ANSYS finite element analysis, we have developed tilting polyimide support structures, which are fabricated on silicon wafers. High frequency ultrasound transducers (20-30 MHz) have been built on these structures and IFAs used to tilt them to steer the ultrasound beam in fluids. Prototype structures have produced 20 degree sector scans scanning at frequencies up to 30 Hz. IFAs have also been used along with similar support structures to steer optical laser beams up to 45 degrees at frequencies up to 60 Hz. The SWT is a more recent development that operates with much greater force than the IFA that could steer ultrasound and optical beams for similar applications.

A transducer compressible in response to electric power, including a flexible, conductive plastic layer microimprinted with a pattern and a stiff plastic layer containing a conductive embedded sheet.

We will discuss our work to build, characterize, and scale- up a metallized plastic muscle-like actuator called a Spiral Wound Transducer (SWT). Prototype SWTs have been built using microelectronics fabrication methods. The prototypes have demonstrated large amplitude motion and analog response. The prototypes, though small, have demonstrated forces equivalent to 12 grams for compressions of more than 15 percent at 30 Hz. The size of the SWTs is essentially unrestricted. Our work with commercially available metallized Mylar films to produce much larger, more powerful, and lower cost SWT devices will also be discussed.

I . The University of North Carolina at CharlotteDepartment of Electrical and Computer EngineeringCharlotte, NC 282232. Duke UniversityDepartment of Biomedical EngineeringDurham, NC 277063. MCNC, Electronic Technologies DivisionResearch Triangle Park, NC 277094. The University of North Carolina at CharlotteDepartment of ChemistryCharlotte, NC 282235. The University of North Carolina at CharlotteDepartment of Mechanical EngineeringCharlotte, NC 282236. Integrated Electronic Innovations Inc.Cary, NC 27513ABSTRACTA miniature ultrasound scanner has been constructed using a MEMS actuatorcalled an Integrated Force Array (IFA).1'2'3'4'5 A second type of actuator called aSpiral Wound Transducer (SWT) is under development and shows significantpromise for this application. Both the scanner and SWT will be discussed.1. MINIATURE ULTRASOUND SCANNERWe have previously discussed the miniature ultrasound scanner6 shown inFigure 1.

The authors present polyimide amplified piezoelectric bimorph scanning mirrors for application in optical coherence tomography (oct). These devices use piezoelectric bimorph actuators to drive microfabricated polyimide structures at resonance. These devices have tilting tables (either 1.125 or 2.25mm wide) that tilt on 3μm thick torsion hinges to amplify the motion of the bimorph actuators and produce large scan ranges. These devices have been integrated into the scanning arm of a spectral domain OCT imaging system. Preliminary in vivo images have been obtained with scans of 40°–50° at real-time imaging rates of 25–41frames∕s.

Microelectromechanical (MEMS) oscillatory devices are placed adjacent a face of a microelectronic sensor platform and configured to oscillate to improve transport to the sensor of substances to be detected. The MEMS oscillatory devices can be configured to oscillate to disrupt the boundary layer that is formed adjacent the face of the microelectronic sensor platform, which may improve sensor performance. MEMS oscillatory devices may be far less susceptible to wear and breakdown than MEMS rotary devices, such as fans.

Compact electrostatic micromirror structures for use in the scanning arm of an optical coherence tomography (OCT) system are described. These devices consist of millimeter-scale mirrors resting upon micrometer-scale polyimide hinges that are tilted by a linear micromachine actuator, the integrated force array (IFA). The IFA is a network of deformable capacitor cells that electrostatically contract with an applied voltage. The support structures, hinges, and actuators are fabricated by photolithography from polyimide-upon-silicon wafers. These devices were inserted into the scanning arm of an experimental OCT imaging system to produce in vitro and in vivo images at frame rates of 4 to 8 Hz.