Abstract: An ultrasound imaging system that utilizes a short sinusoidal pulse burst for excitation, and performs coherent detection of the reflected signal, resulting in improved signal-to-noise ratio. In addition, the polarity of the rate of change of parameters, principally density, is preserved by the coherent detection. This allows a density versus distance signal to be reconstructed by integrating the coherently detected signal. The system includes components to calculate and apply all necessary phase corrections.

Abstract: An obturator for measuring incident light in a remote situs such as a body cavity which includes a treatment tubular member through which light is delivered to the remote situs and one or more auxiliary tubular members through which incident light in the remote situs is transmitted to an external light detector. The treatment and auxiliary tubular members are attached to a connector element which is in turn connected to a cystoscope lens port. The treatment and auxiliary tubular members are aligned off-center with respect to the central axis of the obturator so that a cystoscope lens can be inserted in the lens port and pass through the axial center of the obturator. Each auxiliary tubular member receives incident light from a different portion of the remote situs. The apparatus is particularly useful for conducting phototherapy in body cavities and has been demonstrated in the phototherapy treatment of superficial cancer in the bladder.

Abstract: A device for measuring incident light in a remote situs such as a body cavity which includes a central tubular member through which light is delivered to the remote situs and one or more auxiliary tubular members through which incident light in the remote situs is transmitted to a light detector. Each auxiliary tubular member receives incident light from a different portion of the remote situs. The apparatus is particularly useful for conducting phototherapy in body cavities and has been demonstrated in the phototherapy treatment of superficial cancer in a bladder.

Abstract: An obturator for measuring incident light in a remote situs such as a body cavity which includes a treatment tubular member through which light is delivered to the remote situs and one or more auxiliary tubular members through which incident light in the remote situs is transmitted to an external light detector. The treatment and auxiliary tubular members are attached to a connector element which is in turn connected to a cystoscope lens port. The treatment and auxiliary tubular members are aligned off-center with respect to the central axis of the obturator so that a cystoscope lens can be inserted in the lens port and pass through the axial center of the obturator. Each auxiliary tubular member receives incident light from a different portion of the remote situs. The apparatus is particularly useful for conducting phototherapy in body cavities and has been demonstrated in the phototherapy treatment of superficial cancer in the bladder.

Abstract: An EPR imager and spectrometer includes pulse generating system for generating broadband pulses having an RF carrier frequency that is not highly absorbed by biological samples. The pulse generating system includes up and down chirp convertors for frequency modulating a carrier frequency pulse and compressing the frequency modulated pulse to form a broadband excitation pulse of high energy. Such a machine could form the basis of a clinical imaging device capable of high sensitivity to free radical species in human patients.

Abstract: A method of optimizing photodynamic therapy in which retained concentrations of photosensitizers administered are measured on a real time basis by percutaneous measurements of fluorescence. A light weight hand held fluorometer is used to percutaneously measure fluorescence emitted by photosensitizers in a tissue situs that is subject to photodynamic therapy. The use of real time determinations of the concentration of photosensitizers allow optimization of illumination intensity and duration.

Abstract: A light sensor constructed from a commercial photodiode packaged in a transparent housing of sufficient thickness to set the photodetector away from the underlying surface, thereby reducing the shadowing effects of the photodetector and allowing incident light to pass through the housing to the tissue below. Electrical connections are made directly on the photodiode which is sealed within the transparent housing, thus avoiding electrical shock or short circuit hazards. The transparent package is equipped with four hooks which are well suited for attachment to tissue structure, either directly or with the aid of sutures. In a second embodiment, the light sensor includes a second photodiode mounted within the sealed housing to measure light reflected from the underlying tissue. The light sensor is well suited for use with photodynamic therapy.

Abstract: A high resolution digital thermometer capable of measuring temperature differences on the order of several micro-degrees centigrade. The device includes a bridge circuit having two thermistors in series. An output of the bridge circuit feeds a signal to an analog-to-digital convertor via a high gain amplifier. A computer maintains the balance of the bridge circuit to avoid a situation wherein the range of the analog-to-digital convertor would be exceeded.

Abstract: A discriminator circuit for use with a scintillation detector, wherein the scintillation detector output is fed to a time discriminator and the output of the time discriminator is fed via a short precision delay device to one input terminal of a transmission gate device. The detector output signal is also fed to a fast energy discriminator whose output is furnished as an enable signal to the other input terminal of the transmission gate device, providing time output pulses. Timing pulses from the transmission gate device are furnished to a long non-precision delay device and then to one input terminal of a transmission gate. The detector output signal is also fed through a slow energy discriminator and an enable line to another input terminal of the last-named transmission gate, providing energy output pulses in an energy output line which are furnished to the subsequent portion of the system.

Abstract: A positron emission tomographic scanner is provided with cross-slice event data handling capability by adding only a coincidence detector and register in common to the circuitry for two adjacent planar detector arrays and adding an OR gate to the circuitry for each array. The improvement permits the same circuitry to be utilized for both cross-slice event processing and intra-slice event processing. Selection of the identification code for a detector is determined by a first coincidence detector in the case of an intra-slice event and the added coincidence detector in the case of an inter-slice event.

Abstract: A gamma ray scintillation coincidence detection circuit having four inputs connected to two gating configurations, fed by gamma ray detector units. Detection in any one of the four inputs develops a disabling signal in one signal path leading to an AND gate. Detection in any two of the four inputs results in a system output in another signal path. When any input goes high, the AND gate is disabled after a predetermined settable time delay T. If a second input goes high before the expiration of the delay time T, then the signal in the other path can pass through the AND gate and sets a latch, signifying that detector coincidence has occurred.

Abstract: A gamma ray coincidence analysis system for a multichannel nuclear imaging device of the type employing scintillation detectors in ring-like arrays, with the detectors arranged in quadrants of the rings. The scintillation detectors in a ring have output circuits including respective timing discriminators and OR gates, and respective energy discriminators providing delayed energy pulses, and wherein timing pulses from the respective quadrants are fed via the OR gates to the inputs of a four-input coincidence detector without any delay except for a small delay internal to the discriminators and the very small delay of the OR gates. The delay of the energy pulses at the energy discriminators is for an energy validation period of 500 nsec. The output pulse from the coincidence detector is subsequently delayed for a similar period for verification of the energy levels of the two channels causing the coincidence.

Abstract: A system providing a substantially gapless continuous line display of an analog signal as a function of time on a television monitor. The input is digitized and each level of quantization corresponds to one of the raster display lines to give proper vertical deflection. During each line of raster scan an oscillator and counter sequence the input address to a memory through a desired number of horizontal sampling positions, requiring an address of the order of 8 bits. Each address gives an output of several bits giving in digital form the instantaneous y coordinate of the signal. This is digitally compared with the digitized associated raster line number in a first digital comparator. This is also stored in a register strobed from the above-mentioned counter just before each change of address. The raster line number and the stored previous output are digitally compared in a second digital comparator.