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2003 IEEE Ultrasonics Symposium - Proceedings

作者： Sun, L. Schiano, J. Smith, N.B. Department of Bioengineering Pennsylvania State University University Park 16802 United States Department of Electrical Engineering Pennsylvania State University University Park 16802 United States Graduate Program in Acoustics Pennsylvania State University University Park 16802 United States

A novel model reference adaptive control (MRAC) method was proposed and tested with a transrectal intracavitary applicator for thermal treatment of prostate disease using ultrasound hyperthermia. Two significant advantages of this innovative adaptive control method are: 1) there is no need of a priori knowledge of the tissue properties and 2) the controller could adaptively change the amplitudes and phases of the array's driving signal according to the perfusion rate and other dynamic tissue properties. Computer simulations, ex vivo and in vivo experimental results all showed that with this adaptive controller the tissue was heated up to 43 ± 0.2°C within 7 ± 2 minutes, and adaptively maintained 43°C with dynamic blood flow for the rest period of the hyperthermia.

关键词： Adaptive control systems

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Novel adaptive control system for ultrasound hyperthermia treatment of prostate disease

Novel adaptive control system for ultrasound hyperthermia tr...

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IEEE Symposium (IUS) Ultrasonics

作者： L. Sun J. Schiano N.B. Smith Department of Bioengineering Pennsylvania State University University Park USA Department of Electrical Engineering Pennsylvania State University University Park USA Graduate Program in Acoustics Pennsylvania State University University Park USA

A novel model reference adaptive control (MRAC) method was proposed and tested with a transrectal intracavitary applicator for thermal treatment of prostate disease using ultrasound hyperthermia. Two significant advantages of this innovative adaptive control method are: 1) there is no need of a priori knowledge of the tissue properties; and 2) the controller could adaptively change the amplitudes and phases of the array's driving signal according to the perfusion rate or other dynamic tissue properties. Computer simulations, ex vivo and in vivo experimental results all showed that with this adaptive controller the tissue was heated up to 43 /spl plusmn/ 0.2/spl deg/C within 7 /spl plusmn/ 2 minutes, and adaptively maintained 43/spl deg/C with dynamic blood flow for the rest period of the hyperthermia.

关键词： Adaptive control Ultrasonic imaging Hyperthermia Diseases Phased arrays Testing Applicators Adaptive arrays Computer simulation In vivo

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Noninvasive ultrasonic transdermal insulin delivery in rabbits using the light weight cymbal array

Noninvasive ultrasonic transdermal insulin delivery in rabbi...

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2003 IEEE Ultrasonics Symposium - Proceedings

作者： Lee, Seungjun Snyder, Benjamin Meyer, Richard J. Nayak, Vivekanand Markley, Douglas Newnham, Robert E. Smith, Nadine Barrie Bioengineering Department Pennsylvania State University University Park PA 16802 United States Material Research Laboratory Pennsylvania State University University Park PA 16802 United States Applied Research Laboratory Pennsylvania State University University Park PA 16802 United States Electrical Engineering Pennsylvania State University University Park PA 16802 United States Graduate Program in Acoustics Pennsylvania State University University Park PA 16802 United States

The low profile Cymbal array for enhanced insulin transport through in vivo animal skin using rabbits was discussed. Through the use of the cymbal array, the US-insulin experimental group showed a blood glucose level decrease of -208.1 ± 29 mg/dL within 90 minutes. The small increase in blood glucose was attributable to the low skin permeability of insulin. It was shown that the US alone did not alter the blood glucose level of the rabbit.

关键词： Ultrasonic applications

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Noninvasive ultrasonic transdermal insulin delivery in rabbits using the light weight cymbal array

Noninvasive ultrasonic transdermal insulin delivery in rabbi...

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IEEE Symposium (IUS) Ultrasonics

作者： S. Lee B. Snyder R.J. Meyer V. Nayak D. Markley R.E. Newnham N.B. Smith Bioengineering Department The Pennsylvania State University University Park PA U.S.A. Material Research Laboratory The Pennsylvania State University University Park PA U.S.A. Applied Research laboratory The Pennsylvania State University University Park PA U.S.A. Electrical Engineering The Pennsylvania State University University Park PA U.S.A. Graduate Program in Acoustics The Pennsylvania State University University Park PA U.S.A.

The purpose of this study was to demonstrate US transdermal delivery of insulin in vivo using rabbits with a novel, low profile two-by-two US array based on the cymbal transducer. As a practical device, the cymbal array (f=20 kHz) was 37/spl times/37/spl times/7 mm/sup 3/ in size and weighed less than 22g. With a similar intensity (I/sub sptp/=100 mW/cm/sup 2/, 20% duty cycle), our goal was to determine if the same effect could be achieved with rabbits. Fourteen New Zealand White rabbit (2.7-3.4 kg) experiments were performed in three groups: two controls and one US with insulin exposure. The first group (control 1) had insulin placed in the reservoir with no US while the second group (control 2) had saline in the reservoir with US operating at I/sub sptp/=100 mW/cm/sup 2/ for 60 minutes. The third group (US-Insulin) was subjected to insulin with US exposure for 60 minutes (I/sub sptp/=100 mW/cm/sup 2/). At the commencement of the experiment, 0.3 mL of blood was collected from the ear vein to determine the blood glucose level (mg/dL) using a blood glucose monitoring system. The insulin reservoir was removed with the array after the US was turned off at 60 minutes exposure. For both control 1 and 2, the blood glucose level showed an increase at 15 and 30 minutes and remained at approximately +50 mg/dL. For the US-Insulin group, the glucose level was found to decrease -132.6/spl plusmn/35.7 mg/dL in 60 minutes. After the US and insulin were removed, the blood glucose level of US-Insulin group continued to decrease to -208.1/spl plusmn/29 mg/dL. These results indicate the feasibility of using a low cost, light weight Cymbal array for enhanced transdermal insulin delivery using US.

关键词： Insulin Rabbits Optical arrays Blood Sugar Reservoirs Ultrasonic transducer arrays In vivo Ultrasonic transducers Ear

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Ultrasound mediated transdermal in vivo transport of insulin with low profile cymbal arrays

Ultrasound mediated transdermal in vivo transport of insulin...

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2002 IEEE Ultrasonics Symposium

作者： Lee, Seungjun Smith, Nadine Barrie Shung, K. Kirk Bioengineering Department The Pennsylvania State University University Park PA 16802 United States Graduate Program in Acoustics The Pennsylvania State University University Park PA 16802 United States Department of Biomedical Engineering University of Southern California Los Angeles CA 90089 United States

Recent studies have shown that ultrasound mediated transdermal drug delivery offers a promising potential for noninvasive drug administration. Thus, previous investigators have used ultrasound devices such as large, heavy sonicators or commercially obtained transducers for this type of research. This paper aims to demonstrate ultrasound mediated transdermal delivery of insulin in vivo using rats with a novel, low profile two-by-two ultrasound array based on the cymbal transducer.

关键词： Ultrasonic imaging

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Utilization of the high-frequency piezoelectric ceramic hollow spheres for exposimetry and tissue ablation

Utilization of the high-frequency piezoelectric ceramic holl...

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2002 IEEE Ultrasonics Symposium

作者： Al-Bataineh, Osama M. Meyer Jr., Richard J. Newnham, Robert E. Smith, Nadine Barrie Bioengineering Department The Pennsylvania State University University Park PA 16802 United States Applied Research Laboratory The Pennsylvania State University University Park PA 16802 United States Materials Research Institute The Pennsylvania State University University Park PA 16802 United States Graduate Program in Acoustics The Pennsylvania State University University Park PA 16802 United States

Miniature, high-frequency piezoelectric cermic hollow spheres were evaluated for potential use as hydrophones for exposimetry of high intensity ultrasound fields and as minimally invasive ablation devices. As a minimally invasive interstitial ablation device, several in vitro experiments were conducted using two different size spheres. The results demonstrated an increased necrosed tissue volume for increasing exposure time.

关键词： Ultrasonic transducers

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Polarization-gated imaging techniques based on time-resolved stokes vectors for filament tissues

Polarization-gated imaging techniques based on time-resolved...

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Conference on Lasers and Electro-Optics (CLEO 2002)

作者： Sun, Chia-Wei Yang, C.C. Kiang, Yean-Woei Lu, Long-Sheng Lin, Chii-Wann Wang, Xueding Wang, Lihong V. Dept. of Electrical Engineering Grad. Inst. of Electro-Optical Eng. National Taiwan University 1 Roosevelt Road Sec. 4 Taipei Taiwan Department of Pharmacology Graduate Institute of Bioengineering National Taiwan University 1 Roosevelt Road Sec. 4 Taipei Taiwan Biomedical Engineering Program Optical Imaging Laboratory Texas A and M University College Station TX United States

ISBN: (纸本)1557527067

Polarization-gated imaging techniques based on time-resolved Stokes vectors for filament tissues were discussed. The time-resolved Stokes vectors of signals transmitting chicken breast tissue, mouse cardiac muscle tissue, and polystyrene micro-sphere solution were compared. Results showed that with 45 degrees linear polarization and circular polarization output monitoring, better quality images will be obtained.

关键词： Medical imaging

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SmtB-DNA and protein-protein interactions in the formation of the cyanobacterial metallothionein repression complex:: Zn²⁺ does not dissociate the protein-DNA complex in vitro (vol 40, pg 13378, 2001)

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BIOCHEMISTRY 2001年第51期40卷 15869-15869页

作者： Kar, SR Lebowitz, J Blume, S Taylor, KB Hall, LM Graduate Program in Biophysical Sciences Department of Medicine Department of Microbiology and Department of Biochemistry and Molecular Genetics University of Alabama at Birmingham Birmingham Alabama 35294 and Division of Bioengineering and Physical Science National Institutes of Health Bethesda Maryland 20892

The synechococcal metallothionein locus smt consists of two divergent genes: smtA coding for the metallothionein SmtA, and smtB coding for the trans-acting regulator SmtB. The latter binds at two inverted repeats, designated S1/S2 and S3/S4, in the overlapping promoter/operator sites between the two genes. We have determined the binding stoichiometries to the entire operator/promoter DNA and to the separate S1/S2 and S3/S4 half-operator oligonucleotides using sedimentation equilibrium and sedimentation velocity measurements. The full promoter/operator DNA binds two SmtB dimers. The hydrodynamic behavior of this complex supports a compact nucleoprotein structure. Each separate S1/S2 and S3/S4 operator sequence also binds two dimers. An equal molar mixture of separate S1/S2 and S3/S4 operator sequences, in excess SmtB, forms a S1/S2-SmtB:SmtB-S3/S4 bridge complex. Combining these results with previously published binding interference data, which showed consecutive S1/S2 and S3/S4 SmtB occupancy on the operator/promoter DNA, we have developed a model for the establishment of the repression complex that appears to involve significant DNA compaction, presumably DNA bending, stabilized by SmtB-SmtB bridge interactions. DNase I footprinting titrations also showed consecutive S1/S2 and S3/S4 SmtB occupancy. The footprints expand considerably in the presence of Zn2+. Hence, SmtB remains bound to the operator sites when Zn2+ ions are present. This result is further supported by gel retardation assay. Failure of the metal ions to dissociate SmtB from the DNA points to a hitherto unknown function of SmtB in the regulation of the smt locus.

关键词： Bacterial Proteins Amino Acid Sequence Base Sequence Cyanobacteria DNA DNA Footprinting DNA-Binding Proteins Electrophoretic Mobility Shift Assay In Vitro Metallothionein Molecular Sequence Data Oligonucleotides Operator Regions (Genetics) Promoter Regions (Genetics) Protein Binding Protein Conformation Repressor Proteins Research Support Non-U.S. Gov't Research Support U.S. Gov't Non-P.H.S. Sequence Deletion Ultracentrifugation Zinc

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Simulation of depth of interaction effects for pinhole SPECT

Simulation of depth of interaction effects for pinhole SPECT

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IEEE Symposium on Nuclear Science (NSS/MIC)

作者： A.B. Hwang K. Iwata B.H. Hasegawa Bioengineering Graduate Program University of California Berkeley and San Francisco USA Department of Radiology University of California San Francisco San Francisco CA USA Department of Nuclear Engineering University of California Berkeley Berkeley CA USA

Pinhole imaging is receiving attention as a method to enable SPECT of small animals. However, gamma rays passing through the pinhole aperture and entering the detector at an oblique angle can cause parallax errors due to the depth of interaction (DOI) of the incident gamma ray in the absorber layer of the detector. This can cause a displacement and blurring of the position coordinates recorded by the detector, resulting in an error known as the "DOI effect". The DOI effect for projection data can be analytically calculated, but the error due to the DOI effect in reconstructed SPECT images is difficult to predict analytically due to the complexity of reconstruction algorithms. Therefore, we used an analytic model of the DOI effect in the projection data to numerically simulate the acquisition of point sources to determine the point spread function at different points in the object. The resulting projection data were reconstructed using a Feldkamp algorithm, from which point spread functions were extracted to quantify loss in spatial resolution due to the DOI effect. The simulations were performed for 140-keV gamma rays and a 6 mm thick CsI scintillator with a reconstruction volume of (40 mm)/sup 3/. The simulation was repeated with a 10 mm thick high purity germanium (HPGe) detector. These detectors and parameters are representative of a system that can be used for small animal imaging. From these calculations, we estimate tomographic reconstruction contributes a resolution loss of 0.32-0.63 mm FWHM in plane and 0.21-0.42 mm FWHM out of plane of the detector. For the CsI scintillator, the DOI effect contributes a maximum resolution loss of 0.5 mm FWHM in plane and 0.3 mm FWHM out of plane. With the HPGe detector, the DOI effect contributes a spatial resolution loss of 0.6 mm FWHM in plane and 0.5 mm out of plane.

关键词： Image reconstruction Spatial resolution Animals Gamma rays Gamma ray detection Gamma ray detectors Image analysis Algorithm design and analysis Optical imaging Apertures

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Design and utility of a small animal CT/SPECT system

Design and utility of a small animal CT/SPECT system

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IEEE Symposium on Nuclear Science (NSS/MIC)

作者： K. Iwata A.B. Hwang M.C. Wu H.R. Tang A.J. Da Silva K.H. Wong M.W. Dae B.H. Hasegawa Department of Radiology University of California San Francisco San Francisco CA USA Bioengineering Graduate Program University of California Berkeley and San Francisco USA Department of Radiology University of California San Francisco San Francisco USA Department of Nuclear Engineering University of California Berkeley Berkeley CA USA

Recent developments in the genetic engineering of small animals have motivated us to design an in vivo dual-modality CT/SPECT system that can be used to localize and quantify uptake of single-photon radiotracers in mice. The CT system includes a 75-W x-ray tube and a CCD camera, while the radionuclide imager incorporates a CsI(TI) scintillator coupled to a Si photodiode array with interchangeable pinhole collimators. These devices are mounted on a slip-ring gantry to image a 40-mm diameter cylindrical volume, where both modalities share a common field of view without moving the table on which the animal lies horizontally. The calculated modulation transfer function of the radionuclide system exceeds 10% at 1.01p/mm. The spatial resolution of the CT system is 0.1 mm with at scan time of 15 min and a contrast resolution of 1% for soft tissue. The high-resolution CT image can be used to provide a priori information to correct both the visual quality and the quantitative accuracy of the SPECT image. This imaging system and technique is designed for in vivo functional assessments of cancer and cardiovascular disease in small animals.

关键词： Animals Computed tomography In vivo Spatial resolution Genetic engineering Mice X-ray imaging Charge coupled devices Charge-coupled image sensors Photodiodes

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