Abstract: A 3-D region of interest (ROI) of a body is imaged, preferably using an ultrasound transducer. The intensity of an echo signal from each of a pattern of pixels within the ROI is measured and stored. The pixels are then grouped into pixel blocks, and the intensity values for the pixels in each sequentially selected current block are compiled in a current histogram. Each current histogram is compared with a reference histogram that corresponds to the distribution of echo signal intensities in a known region of speckle. A structure likelihood value is then computed based on the comparison, where the structure likelihood value indicates how likely it is that the current block corresponds to a structure of interest as opposed to noise. The intensity value for any pixel likely to be noise is preferably scaled down. The scaled intensity values are then projected, preferably using a maximum intensity projection, onto a 2-D display plane, a representation of which is then displayed for a user to see.

Abstract: An ultrasound system includes a transmit/receive switch (502), at least one frequency band selection circuit (512), and a selection unit (511). The selection unit (511) is used to determine if the data being received are from tissue or contrast agent regions. Depending on which type of region the data are from, different signal processing techniques are applied to the data. For example for tissue regions, a harmonic filter can be applied to the signal. If the signals are from contrast agent flow regions, both the harmonic filter and a fundamental filter can be used.

Abstract: A rotatable multi-element beam shaping device according to embodiments of the invention includes a first assembly, rotatable about a central axis through which a beam passes. The first assembly has a first and a second jaw adapted to move across the central axis to shape the beam. A second assembly, positioned below the first assembly, is also rotatable about the central axis, and has a third and a fourth jaw adapted to move across the central axis to further shape the beam. The first and the second assemblies, according to the invention, are separately controllable.

Abstract: The invention provides a scheme in accordance with which a linear accelerator may be operated in two or more resonance (or standing wave) modes to produce charged particle beams over a wide range of output energies so that diagnostic imaging and therapeutic treatment may be performed on a patient using the same device. In this way, the patient may be diagnosed and treated, and the results of the treatment may be verified and documented, without moving the patient. This feature reduces alignment problems that otherwise might arise from movement of the patient between diagnostic and therapeutic exposure machines. In addition, this feature reduces the overall treatment time, thereby reducing patient discomfort.

Abstract: A unified power architecture for generating high frequency switched power to a load is provided which includes a number of input branches, each input branch receiving direct current (DC) power from a power source. Each input branch includes a switch device coupled to a storage device for generating input pulses, a transformer including a primary winding set receiving the input pulses, and a reset section generating a reset current for setting a core of the transformer. An output section is provided which includes a plurality of windings around a secondary of each transformer of each of the input branches, the output section generating an output pulse including components of each of the input pulses.

Abstract: A segmented cine MR pulse sequence of the “TrueFISP”-type having a short repetition time TR is used to acquire MR data during a single breath hold. In the resulting cine images, the blood and the myocardium have distinctly different image contrasts.

Abstract: A multi-region target that is configured to selectively generate two different energy distributions when exposed to an excitation electron beam is described. The multi-region target includes multiple regions with different x-ray generating characteristics. Thus, the interaction between an excitation electron beam and the target generates an x-ray beam with an energy distribution that depends upon which target region is exposed to the excitation electron beam. The different x-ray spectra may be used to produce an enhanced contrast x-ray image. A method of detecting the rotational position of the multi-region target based upon the contrast level of the resulting images also is described.

Abstract: A method and system for controlling probe heating in an ultrasound system is disclosed. The method and system comprises electrically exciting a transducer within the probe; and detecting at least one pulse characteristic from the excited transducer. The method and system further includes analyzing at least one pulse characteristic to determine if the probe is coupling into a reflecting medium such as air or into tissue. Accordingly, a system and method in accordance with the present invention detects when an ultrasound transducer is coupling energy into a patient or into a reflecting medium such as air. In so doing, the thermal performance of the transducer improves by allowing an increase in the duration and level of the transducer excitation voltage.

Abstract: A transmit beamformer method and system is provided for applying absolute delays between groups of channels and applying relative delays to channels within the groups of channels. For example, every fourth channel is responsive to an absolute delay from a controller. The delay for channels between every fourth channel are set as relative delays corresponding to a further delay in addition to the absolute delay.

Abstract: A high voltage distribution system for distributing a high voltage supply to a plurality of semiconductor radiation detector modules, includes a conductive strip connected to a high voltage supply. The conductive strip is preferably made of aluminum foil, and contacts a surface of each of the detectors. The conductive strip is held into contact with the semiconductor radiation detectors by applying pressure to said conductive strip with a pressure plate, including a compressible layer such as a foam layer. A vacuum is created in an area occupied by the semiconductor modules and the conductive strip. The high voltage distribution system allows a high negative voltage to be applied to the semiconductor detector modules with a minimum of attenuation. In a preferred embodiment, the detector modules are CZT modules, and the system is incorporated into a solid-state gamma camera for nuclear medicine imaging.

Abstract: An x-ray imaging system is described. The imaging system includes a praseodymium (Pr) doped gadolinium oxysulfide (Gd2O2S) scintillator and a detector array positioned adjacent to the scintillator. The scintillator is particularly suited for x-ray imaging applications in which fast scan times are desired.

Abstract: An improved acquisition scheme for a medical imaging and treatment system 100. According to one aspect of the invention, adaptive radiation detection, for determining when therapeutic or diagnostic radiation is being applied, is provided. The imaging device 124 acquires several test images during a preacquisition delay. The maximum intensity level from these test images is defined as the upper limit of a camera 122's response in the darkness. The standard deviation of the intensity distribution is also computed. The image intensity level of the subsequent test images are compared to a radiation detection threshold which is determined to be the upper limit of the camera's dark signal, plus twice the standard deviation of pixel intensity distribution of the dark test images. If the intensities of a statistically significant number of pixels exceeds the threshold, the radiation is considered to be on.

Abstract: A method and system in accordance with the present invention uses the existing hardware and divides the treatment port dose into segments. In between each segment the field, with respect to the beam, would be translated, and the leaf positions would be adjusted to maintain the tumor contour. By integrating the above-identified methodology with a hardware system, accurate conformal radiation therapy is provided while minimizing leakage. In addition, through the present invention, higher dose rates can be provided while not appreciably affecting treatment time.

Abstract: A method for controlling radiation delivery from a radiation source to an object is disclosed. The method includes defining a field on the object for radiation delivery. The field includes a plurality of cells, each cell having a defined treatment intensity level. The cells are grouped to form a matrix having at least one dimension approximately equal to a width of a collimator leaf capable of blocking radiation emitted from the radiation source. The method further includes decomposing the matrix into orthogonal matrices and optimizing delivery of the radiation by selecting the orthogonal matrices having minimum vertical and horizontal gradients when combined with adjacent cells. A system for controlling radiation delivery from a radiation source to an object is also disclosed.

Abstract: Aspects for virtual wedge treatment with wedge angle optimization are described. In a method aspect, the method includes adjusting a preselected calibration factor based on chosen treatment conditions. The method further includes achieving an optimal wedge intensity distribution with the adjusted calibration factor for the chosen treatment conditions in a virtual wedge radiation treatment session. Additionally, adjusting includes determining an appropriate calibration factor for a given wedge angle and depth.

Abstract: A combination PET/single photon (SPECT or planar) nuclear imaging system utilizes a pair of dedicated PET detectors and at least one dedicated single photon detector mounted on a single gantry. The single photon detector is a solid-state detector, such as CZT, and the PET detectors are made of a high effective Z material, such as LSO or BGO. Simultaneous PET/single photon imaging studies can be carried by the single system. The solid-state detectors also may be removable and mountable on a separate, dedicated single photon imaging gantry.

Abstract: Gadolinium-based MR contrast agent is administered to a patient. Acquisition of MR data begins at the latest when the bolus of MR contrast agent reaches the patient's heart and continues throughout the first-pass of contrast agent through the coronary circulation. Advantageously, the acquisition is carried out using a T1-weighted, three-dimensional gradient echo sequence that is synchronized to the patient's cardiac cycle to acquire MR data only during diastole, and a T1-weighting magnetization preparation such as inversion-recovery or saturation-recovery is used.

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.