Abstract: A sequence of angiographic images is made up of frames of data. A sample sequence, made up of a number of such frames, is compressed using a lower value of the quantization factor and the resulting average compression ratio is determined. The same sample sequence is also compressed using a higher value for the quantization factor and another average compression ratio is determined. The value of the quantization factor corresponding to a desired average compression ratio of the entire sequence can then be determined by linear interpolation.

Abstract: Method and system aspects for achieving more accurate radiation delivery during radiation treatment by a radiation-emitting system are described. In a method aspect, and system for achieving same, the method includes providing a table of dose rate values for accumulated dosages in a treatment unit of the radiation emitting system, and controlling a dose rate of radiation emitted from the radiation emitting system through utilization of the table of dose rates. Controlling further includes determining an accumulated dosage at a sampling point, and comparing the accumulated dosage to a total desired dosage. The dose rate is adjusted based on the table of dose rate values and the determined accumulated dosage, with the dose rate ramped down as the accumulated dosage nears the total desired dosage. Accumulated dosages include fractional numbers of monitor units.

Abstract: An ultrasound imaging system produces three-dimensional tissue/flow images by first computing a plurality of separate two-dimensional tissue images and two-dimensional flow images. Separate tissue and flow volumes are created by applying the tissue and flow images to a three-dimensional construction algorithm. Each of the separate tissue and flow volumes is analyzed using a three-dimensional rendering algorithm to produce a rendered tissue and flow image. The separately rendered tissue and flow images are combined to produce the combined tissue/flow image. In addition, the present invention provides visual cues that allow a user to create more even scans. The invention also includes a method for correcting for probe movement. The invention also produces an image that is calculated from the partial volume data as it is being created to give a user feedback on the quality of the image they are producing.

Abstract: System and method aspects for a photoconductive element for direct x-ray detection in a radiography imaging system are described. The photoconductive element includes a photoconductive material layer for absorbing x-ray radiation transmitted through an object being imaged by the radiography imaging system. Further included is an interdigital contact structure in the photoconductive material layer.

Abstract: A method and a system for storing and managing dimensional measurement values and the underlying ultrasound images utilize a report generator that operates to generate an examination report of an ultrasound examination having saved measurement values. The examination report allows for an expedient access to the corresponding ultrasound images that were used to derive the measurement values. In addition, the report generator operates to automatically save the ultrasound image when a measurement value that was computed from that ultrasound image is saved. This feature ensures that for each saved measurement value, the corresponding ultrasound image is also saved. The system utilizes ultrasound waves to image various anatomical features of a patient or a fetus. Examples of anatomical features that may be imaged by the system include the femur, the humerus and the head of a fetus. These ultrasound images are used to compute measurements of the anatomical features.

Abstract: According to an embodiment of the present invention, an isocenter of an image may be found by using a multi-leaf collimator. According to this embodiment, a center leaf is projected into the center of the x-ray field with all other leaves retracted. An image is acquired. A line through the center of the center leaf is identified. This line is also a line through isocenter. Another method according to an embodiment of the present invention for finding isocenter uses an accessory. The accessory according to an embodiment of the present invention includes a metal marker in the center of the accessory with metal markers interspersed away from the center at a predetermined interval. An image may be acquired through the accessory, with the patient on the table. The resulting image may be analyzed to identify the position of the metal markers to determine isocenter.

Abstract: Method and system aspects for achieving more accurate radiation delivery during radiation treatment by a radiation-emitting system are described. In a method aspect, and system for achieving same, the method includes providing a table of dose rate values for accumulated dosages in a treatment unit of the radiation emitting system, and controlling a dose rate of radiation emitted from the radiation emitting system through utilization of the table of dose rates. Controlling further includes determining an accumulated dosage at a sampling point, and comparing the accumulated dosage to a total desired dosage. The dose rate is adjusted based on the table of dose rate values and the determined accumulated dosage, with the dose rate ramped down as the accumulated dosage nears the total desired dosage. Accumulated dosages include fractional numbers of monitor units.

Abstract: A technique for resetting a HPF for improving its settling time in response to a sharp transition in its input signal, by rapid input and clocking through the high-pass filter (HPF) of new data samples after occurrence of the sharp transition. The new data samples comprise an artificial ramp representative of the expected average slope of the input signal that should be maintained after occurrence of the sharp transition. The artificial ramp can be generated using “a priori” knowledge of the expected average slope of the input signal, or alternatively, can be generated using a direct measurement of the slope of the input signal at the time the HPF is to be reset. In the event that both the direct slope measurement and “a prior” slope knowledge are available at the time the HPF is to be reset, and they differ from each other, it is desirable to generate an artificial ramp whose slope provides a smoothed transition from the latter slope measurement to the former slope.

Abstract: A shielded conductor path comprising: a first signal conductor having an input end for acquiring a physiological signal and an output end for coupling the physiological signal to a physiological signal input of a patient monitor, and a second signal conductor positioned with respect the first signal conductor for acting as a shield therefore. An inductance connected in series between an output end of the second signal conductor and the reference signal input of the patient monitor forms a filter circuit which attenuates the level of an interference signal in the second signal conductor. In one preferred embodiment of the invention, the inductance is part of an RLC filter circuit contained in a housing which is selectively insertable between an EKG lead set and the EKG signal input of a patient monitor. The selectively insertable filter permits the use of standard EKG lead sets in the presence of RF electrosurgery procedures, without risk of burning the patient at the site of the EKG electrodes.

Abstract: A system and method for radiation therapy delivery. Known errors are compensated for by applying an offset factor to the dose at the start of the beam cycle. According to one embodiment of the invention, a dosimetry controller is configured to provide the offset connection and sense radiation on (RAD ON) and monitor the dose rate at the beginning of the beam cycle.

Abstract: A system and method for radiation therapy delivery. The present invention provides for optimizing radiation delivery by accounting for the physical attributes of a beam shielding device (401) when determining an optimal radiation treatment. These include, for example, constraining the optimization engine with realizable positioning of plates and/or collimator leaves. Thus, an optimal set of fields and intensity levels for those fields are chosen.

Abstract: During acquisition of one frame of MR data, the phase-encoding gradient oscillates between a maximum phase-encoding gradient and a minimum phase-encoding gradient. Each oscillation includes a zero phase-encoding gradient.

Abstract: Circuits and methods are described for providing gate drive to a gate terminal of a first switching device. The circuit includes a transformer having a core, a primary winding, and at least one secondary winding. The primary winding of the transformer is for coupling to a power source. The at least one secondary winding is for coupling to the gate terminal of the first switching device. A second switching device is connected in series with the primary winding of the transformer. The second switching device controls conduction of current in the primary winding which causes energy to be stored in the core of the transformer. The second switching device is operable to stop the current from flowing in the primary winding thereby causing a current pulse to be generated in the at least one secondary winding from the energy stored in the core. The current pulse is used for driving the gate terminal of the first switching device.

Abstract: A cylindrical alkali halide melt-grown single-crystal-type ingot is axially compressed in a heated dual-platen press while in a plastic state. The ingot is located mid-way between two parallel, planar, vertically extending barriers. By properly orienting the platens and the barriers with respect to the crystal lattice structure of the ingot, the ingot can be forged into a rectangular block that is not only devoid of peripheral cracks and fissures but that also has more uniform properties even when impurities and activator (Tl, in the case of NaI(Tl)) are not uniformly distributed within the initial single-crystal ingot.

Abstract: A graphical user interface (1000) for use in a patient treatment system. The graphical user interface (1000) permits graphical display and editing of individual treatment parameters, including machine (2, 4, 6) positions and field shapes. Multiple fields grouped sequentially as an intensity modulated field (IMG) may be viewed as a superimposed graphical composite (1020, 1022, 1024, 1026). In addition, a pictorial representation of the radiation beams (1026) incident on a particular target is provided. A graphic representation of field shape (1030) is provided; the graphics change as treatment progresses. Finally, manipulation of graphics permits editing of treatment information, while allowing immediate feedback as to the result of the change.

Abstract: Method and system aspects for utilizing portal images in a virtual wedge treatment during radiation treatment by a radiation-emitting device are described. In a method aspect, and system for achieving same, the method includes utilizing an image dose with a static jaw gap position to initiate a virtual wedge treatment with portal imaging. The method further includes continuing with the virtual wedge treatment from a reduced jaw gap position with a dynamic dose and dynamic jaw positioning. In addition, the virtual wedge treatment in completed with a static dose in the static jaw gap position.

Abstract: By administering MR contrast agent such as Gd-DPTA, waiting for a predetermined period of time and then acquiring T1-weighted MR image data, infarcted myocardial tissue can be distinguished from injured myocardial tissue. An in vivo cine MR study is used to distinguish normal myocardial tissue from injured or infarcted myocardial tissue. As a result, it is possible to distinguish between normal, injured but living, and infarcted myocardium using MR imaging.

Abstract: A system and method for maintaining a network of multiple radiation devices, such as linear accelerator radiation therapy devices. Automated specification testing and checking of the network of radiation therapy devices facilitates integrated analysis of collected information and system calibration. A network interface is provided for coupling the radiation devices to the network through dedicated personal computers (PCs). Databases of device history records and device specifications are maintained on a system calibration server for each of the multiple radiation devices. Dosimetry scanners operable with the radiation devices use a dedicated PC as a client user interface in communication with the server via the network and one radiation device. The radiation devices are responsive to the client user interface for undergoing an operation sequence with dosimetry scanner performing a series of tests.

Abstract: Reflectors such as microbubbles in a contrast agent introduced into a blood vessel of a patient are destroyed (or otherwise acoustically altered) using focused ultrasound at a modulation point according to an input modulation sequence. This creates “gaps” in the flowing contrast agent that are sensed at a downstream sensing point. The pattern of gaps is then matched in time with the input modulation sequence to determine a transit time for the gaps, which is also the flow velocity of the blood. The input modulation sequence creates at least two gaps, but may otherwise have any of several different forms, which include, among others, square-wave, maximal sequence, random binary patterns. Edge-detection and correlation techniques are used to match the input and sensed gap patterns. By triggering the input sequence off of a heart rate monitor, a flow velocity profile may also be calculated and displayed from one heart beat to the next.

Abstract: A docking station for a portable patient monitor is adapted for use in a system which includes a communications network and, optionally, a bedside display. The portable monitor is coupled to sensors for receiving patient data signals. The docking station includes a platform that can be conveniently located near the patient. The platform has a detachable mounting which holds the portable monitor. When the portable monitor is mounted on the docking station platform, it receives power from the docking station. At the same time, the docking station receives patient data from the portable monitor and transfers the data to the communications network. The docking station is also coupled, via the communications network, to a plurality of input and output devices when it is mounted on the docking station. A second example of the docking station includes a power supply and network (PSN) box that is mounted to a wall or other fixed surface.