Thermoacoustic emissions induced by 2450 MHz microwave pulses in water, tissue-simulating phantoms and dog kidneys have been detected. The analytic signal magnitude has been employed in generating 'A-mode' images with excellent depth resolution. Thermoacoustic emissions have also been detected from the dose-gradient at the beam edges of a 4 MeV x-ray beam in water. These results establish the feasibility of employing thermoacoustic signals in generating diagnostic images, and in locating x-ray beam edges during radiation therapy. A theoretical model for thermoacoustic imaging using a directional transducer has been developed, which may be used in the design of future thermoacoustic imaging system, and in facilitating comparisons with other types of imaging systems. A method of characterizing biological tissues has been proposed, which relates the power spectrum of the detected thermoacoustic signals to the autocorrelation function of the thermoacoustic source distribution in the tissues. The temperature dependence of acoustic signals induced by microwave pulses in water has been investigated. The signal amplitudes vary with temperature as the thermal expansion of water, except near 4°C. The signal waveforms show a gradual phase change as the temperature changes from below 4° to above 4°C. This anomaly is due to the presence of a nonthermal component detected near 4°C, whose waveform is similar to the derivative of the room temperature signal. The results are compared to a model based on a nonequilibrium relaxation mechanism proposed by Pierce and Hsieh. The relaxation time was found to be (0.20±0.02) ns and (0.13±0.02) ns for 200 ns and 400 ns microwave pulse widths, respectively. A microwave-induced thermoacoustic source capable of launching large aperture, unipolar ultrasonic plane wave pulses in water has been constructed. This source consists of a thin water layer trapped between two dielectric media. Due to the large mismatch in the dielectric constants, the incident microwaves undergo multiple reflections between the dielectric boundaries trapping the water, resulting in an enhanced specific microwave absorption in the thin water layer. This source may be useful in ultrasonic scattering and attenuation experiments.

The Totally Digital Imaging System (TDIS) is based on system requirements information from the Radiology Department, University of Arizona Health Science Center. This dissertation presents the design of this complex system, the TDIS specification, the system performance requirements, and the evaluation of the system using the computer simulation programs. Discrete event simulation models were developed for the TDIS subsystems, including an image network, imaging equipment, storage migration algorithm, data base archive system, and a control and management network. The simulation system uses empirical data generation and retrieval rates measured at the University Medical Center hospital. The entire TDIS system was simulated in Simscript II.5 using a VAX 8600 computer system. Simulation results show the fiber optical image network to be suitable, however, the optical disk storage system represents a performance bottleneck.

A high speed, 125 mega-bit per second data rate, data communication channel using fiber optic technology is described. Medical image data, generated by CT scanner or magnetic resonance imaging type imaging equipment, passes from standard American College of Radiology - National Electrical Manufactures Association (ACR-NEMA) interface equipment to the High Speed Fiber Optic Network Interface (HSFONI). The HSFONI implements the ACR-NEMA standard interface physical layer with fiber optics. The HSFONI accepts data from up to 8 devices and passes data to other devices or to a data base archive system for storage and future viewing and analysis. The fiber components, system level, and functional level considerations, and hardware circuit implementation are discussed.

This paper describes the design and simulation of a network interface unit (NIU) for a picture archiving and communication system (PACS) network called PACnet. PACnet is a dual fiber optic ring network under development at the Computer Engineering Research Laboratory of the University of Arizona. This network integrates voice, data, and image communications in a hospital environment and supports a throughput rate between 200-500 megabits per second. At each node in the network, an NIU implements the Data Link Layer and Physical Layer protocols of PACnet. The initial network interface unit design for PACnet was a functional description of NIU protocols and major components. In order to construct a demonstration prototype of PACnet,the NIU description must be refined and an architecture must be specified. The NIU design is specified and simulated using the hardware description language VHDL. Simulation results provide information on NIU timing characteristics and logic families required to implement the NIU.

Though several clinical monitoring ways exist and have been applied to detect cardiac atril fibrillation (A-Fib) and other arrhythmia, these medical interventions and the ensuing clinical treatments are after the fact and costly. Current portable healthcare monitoring systems come in the form of Ambulatory Event Monitors. They are small, battery-operated electrocardiograph devices used to record the heart's rhythm and activity. However, they are not energy-aware ; they are not personalized ; they require long battery life, and ultimately fall short on delivering real-time continuous detection of arrhythmia and specifically progressive development of cardiac A-Fib. The focus of this dissertation is the design of a class of adaptive and efficient energy-aware real-time detection models for monitoring, early real-time detection and reporting of progressive development of cardiac A-Fib.... The design promises to have a greater positive public health impact from predicting A-Fib and providing a viable approach to meeting the energy needs of current and future real-time monitoring, detecting and reporting required in wearable computing healthcare applications that are constrained by scarce energy resources. / by Redjem Bouhenguel. / Thesis (Ph.D.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.