Abstract: Systems and methods for estimating the location of a wave source based upon low frequency measurements acquired using multiple receivers. In one aspect, a method for estimating an end range of a radiation beam delivered to a target is provided. The method includes controlling a radiation treatment system to deliver a radiation beam inducing at least one low frequency thermoacoustic wave inside a target, and detecting, using receivers positioned about the target, sonic signals corresponding to the at least one low frequency thermoacoustic wave. The method also includes analyzing the sonic signals to determine differences in times-of-flight associated with different receivers, and estimating an end range of the radiation beam by correlating the differences in times-of-flight. The method further includes generating a report indicative of the end range of the radiation beam.

Abstract: Systems and methods for estimating the location of a wave source based upon low frequency measurements acquired using multiple receivers. In one aspect, a method for estimating an end range of a radiation beam delivered to a target is provided. The method includes controlling a radiation treatment system to deliver a radiation beam inducing at least one low frequency thermoacoustic wave inside a target, and detecting, using receivers positioned about the target, sonic signals corresponding to the at least one low frequency thermoacoustic wave. The method also includes analyzing the sonic signals to determine differences in times-of-flight associated with different receivers, and estimating an end range of the radiation beam by correlating the differences in times-of-flight. The method further includes generating a report indicative of the end range of the radiation beam.

Abstract: An MRI system acquires image data using a spiral pulse sequence in which k-space is sampled in a trajectory comprised of a spiral segment and a symmetric spiral tail segment. The spiral segments partially sample throughout the extent of k-space and the symmetric spiral tail segment samples only in a central region of k-space. The central region of k-space is fully sampled and a phase correction method is used to reconstruct an image from the under-sampled peripheral k-space data set.

Abstract: A method and apparatus for imaging an object by applying imaging energy from a source to the object such that a cone beam of imaging energy (40) that has passed through the object is detected by a detector. In contrast to known methods, direct x-ray inversion of the cone beam measurements is made, where the inversion includes a backprojection step that precedes the filtering step. The inverted cone beam measurements are backprojected on the fly, thereby reducing lag time between the end of data collection and image generation to the time required to perform a fast Fourier-based filter of the backprojected data.

Abstract: A method and apparatus are provided which utilize a circular tomosynthesis system to collect 2-D x-ray projection radiograph data of an object being evaluated. The collected data is then transformed into a form suitable for cone beam volumetric computed tomography (cone beam VCT) reconstruction. Once the data has been transformed, a cone beam VCT reconstruction algorithm may be utilized to reconstruct a 3-D image of the object.

Abstract: A monitoring apparatus analyzes detector data from a CT system to detect a signature of a bad detector. The apparatus generates a plurality of Helgason-Ludwig condition values from the detector data. The generated values are processed to generate a comparison value, which is compared to a predetermined threshold value. A warning message may be generated when the comparison value exceeds the predetermined threshold value, the warning message alerting an operator to the likely presence of a bad detector. In one embodiment, the generated values are further analyzed to generate an estimate of the position of the bad detector. In a preferred embodiment, the comparison value is a matrix norm of a matrix generated from the Helgason-Ludwig condition values.

Abstract: A source applies imaging energy that passes through an object being imaged and is then detected by a detector. A scanning trajectory causes the detector to provide measured cone beam data to a processor. The measured cone beam data is over a characteristic surface with a corresponding characteristic problem. The processor solves the characteristic problem such that missing cone beam data is determined. The measured cone beam data and the determined cone beam data together provide a complete data set for exact image reconstruction.

Abstract: A source applies imaging energy that passes through an object being imaged and is then detected by a detector. A scanning trajectory causes the detector to provide a Cauchy data set of measured cone beam data to a processor. The processor extrapolates by use of John's equation such that missing cone beam data is determined. The measured cone beam data and the determined cone beam data together provide a complete data set for exact image reconstruction.