Abstract: A nuclear camera (10) includes a plurality of detector heads (12) which have collimators (14) for fixing the trajectory along which radiation is receivable. A rotating gantry (22) rotates the detector heads around the subject collecting less than 360° of data, e.g., 204° of data. A zero-filling processor (50) generates zero-filled projection views such that the actually collected projection views and the zero-filled projection views span 360°. A smoothing processor (56) smooths an interface between the zero-filled and actually collected projection views. The zero-tilled and smoothed views are Fourier transformed (60) into frequency space, filtered with a stationary deconvolution function (62), and Fourier transformed (64) back into real space. The resolution recovered projection data sets in real space are reconstructed by a reconstruction processor (68) into a three-dimensional image representation for storage in an image memory (70).

Abstract: A magnetic resonance angiographic method includes acquiring (70) high resolution volume image data comprising data (74) corresponding to a plurality of high resolution image slices, and acquiring (72) data corresponding to at least one vessel identification image slice (76), said acquired data having selectively enhanced contrast for one of arteries and veins. A high resolution volume image representation (80) is reconstructed from the acquired high resolution volume image data (74). At least one vessel identification slice image representation (82) is reconstructed from the acquired data corresponding to at least one vessel identification image slice (76). At least one of an artery starting point (86) and a vein starting point (88) is identified based on the vessel identification slice image representation (82).

Abstract: A subject (10) is disposed adjacent a detector array (18) for the purposes of nuclear imaging. The subject (10) is injected with a radioactive isotope (14) and &ggr;-ray emissions indicative of nuclear decay are detected at the detector array (18). P-ASIC (60) preamplifier circuits are complex low-noise integrated circuits which dissipate a considerable amount of power (300-500 mW each). These components account for most of the dissipated power on the daughter cards (62). In order to facilitate the cooling of these electrical components, they are mounted on circuit boards (62) that are arranged parallel to each other extending perpendicularly away from the detector array (18). This provides channels between the boards through which cooling air is drawn by an array of fans (84).

Abstract: An x-ray tube (1) includes a heat shield (130) which intercepts heat radiating from an anode (10), thereby reducing the temperature of a bearing assembly (62). The heat shield includes outer and inner concentric cylinders (132, 134) spaced from each other by a vacuum gap (138). The heat shield and a stationary portion (114) of the bearing assembly are both connected to a cold plate (150) so that heat is not conducted from the cylinders to the bearing assembly but is instead carried away by the cold plate to the surrounding cooling oil.

Abstract: In magnetic resonance angiography (MRA), the MRA data (40) is smoothed and converted into an isotropic format (52). A binary surface fitting mask (56) that differentiates vascular regions from surrounding tissue is generated from the isotropic MRA data. Vascular starting points (60) are identified based on the binary surface fitting mask. The vascular system corresponding to each starting point is tracked (62). The tracked vascular system is graphically displayed (68). Preferably, the arteries and the veins in the binary surface fitting mask data are differentiated (58) based on anatomical constraints. The tracking (62) preferably includes estimating an oblique plane that is orthogonal to the vessel (204), determining the vessel edges in the oblique plane (212), and determining an estimated vessel center in the oblique plane (216). The vessel edges are preferably determined by determining a raw vessel edge (208), and refining the raw vessel edge to obtain a refined vessel edge representation (212).

Abstract: A parameter compilation memory (62, 114) stores patient physiological information and contrast agent arrival or uptake times (tD, tA, tV) from past patients. A triggering or synchronizing window processor (64, 112) sets a triggering window, i.e. estimates the arrival time, based on the past patient information. A subject (16) disposed within an imaging region (12, 90) is injected with a contrast agent (66). Arrival of the contrast agent in the imaging region is detected (72, 110) with a real time tracking method. Diagnostic imaging is commenced on the first to occur of the detection of contrast agent arrival within the window and the end of the triggering window. The uptake times for the subject (16) are compared to those stored in the memory (62, 114) and analyzed to propose a diagnosis.

Abstract: An apparatus (20) for setting a filament (22) on an electrode (24) comprises a body (52) having a central member (54) with a longitudinal axis (A-A), a first end member (56) and a second end member (58). The first and second end members (56, 58) are located at opposite ends of the central member (54) and each extends away from the longitudinal axis (A-A) thereby forming a recess (59). Each end member (56, 58) includes a surface generally facing the recess (61, 63) and an outer surface (74, 76). A bore (68) in the body is adapted to receive a retaining member (not shown) for mounting the body (52) to the electrode (24). A cavity (70) extends through the first end member (56) from its outer surface (74) to its recess facing surface (61). A cavity (80) in the second end member (58) opens toward the recess (59). The cavities (70, 80) in the first end member (56) and second end member (58) are located opposite one another across the recess (59).

Abstract: To image flowing materials, magnetic resonance preconditioning pulses are applied in an upstream region (28). For scanning a subject, an RF pulse calibration sequence is performed by generating a corresponding magnetic resonance data line (361, . . . , 36n) in each of a plurality of slices (401, . . . , 40n) along a vessel. A processor (54) determines a signal intensity for each slice (56), fits the intensities for the family of slices to a curve (58), and adjusts an RF pulse profile with spatial position in accordance with the curve which is dynamically dependent on the scanned subject. In a subsequent imaging sequence with the adjusted tip angles, data lines from each of the slices are received (52) and reconstructed (62) into an image representation stored in the memory (64).

Abstract: A gradient coil assembly (22) generates magnetic field gradients across the main magnetic field of a magnetic resonance imaging apparatus and includes a base gradient coil set which generates magnetic field gradients which are substantially linear over a first useful imaging volume, and a correction gradient coil set which generates magnetic field gradients having substantially no first order moment. The correction gradient coil set produces third and higher order moments which combine with higher order terms of the base gradient coil set to produce magnetic field gradients which are substantially linear over a second useful imaging volume different from the first useful imaging volume. In a preferred embodiment, the second volume is continuously variable by adjusting the amounts of current applied to the base and correction coils.

Abstract: An MRI apparatus includes a local endovaginal probe (30) for receiving magnetic resonance in a study of the endopelvic fascia surrounding the female urethra. The probe (30) includes a shaft portion (62) an insert portion (60), the insert portion to be inserted into the vaginal cavity of a female subject. The insert portion (60), in order to have maximum efficiency in imaging the endopelvic fascia, is designed to specific dimensions to achieve the optimum balance between image quality and patient comfort. In an imaging sequence, a main magnet assembly (12) produces a main magnetic field through an imaging region (14). A whole-body RF coil (26) excites and manipulates magnetic resonance in the vicinity of the vaginal cavity. The probe (30) detects the magnetic resonance, which is received and demodulated. The received magnetic resonance is then reconstructed into an image representation of the tissue surrounding the vaginal cavity of the subject.

Abstract: A pair of quadrature radio frequency coils (32, 34) disposed adjacent an imaging region (10) are typically loaded differently due to factors such as subject geometry, subject mass, and a relative distance from the subject. A tip angle adjustment circuit (50) monitors a combined tip angle adjacent a mid-plane of the examination region, such as by analyzing delivered and reflected power to each of the coils. An adjustment circuit (54) adjusts relative RF power or amplitude to produce a selected, combined tip angle in the examination region.

Abstract: In radiation oncology, a magnetic resonance apparatus is used to plan a treatment regimen. The oncologist uses the features of slice width selection, and depth selection to better ascertain where a medical malignancy is within a patient. In order to facilitate a user-friendly atmosphere for the oncologist, a new user control interface (50) is added to an MRI apparatus that includes controls normally found on a typical oncology linear accelerator. A conversion algorithm (52) translates the linac input into an imaging region for a magnetic resonance sequence that images the malignancy. Along each planned treatment trajectory radiation and MR projection images are superimposed to delineate the malignancy clearly for beam aiming and collimation adjustments.

Abstract: A computerized tomographic imaging system including a stationary gantry portion defining an examination region and a rotating gantry portion for rotation about the examination region. An x-ray source is disposed on the rotating gantry portion for projecting x-rays through the examination region. A plurality of modular radiation detector units are disposed across the examination region from the x-ray source. Each radiation detector unit includes an array of x-ray sensitive cells for receiving radiation from the x-ray source after it has passed through the examination region and for generating an analog signal indicative of the radiation received thereby. Each radiation detector unit also includes a plurality of integrated circuits connected to the x-ray sensitive cells with each integrated circuit including a plurality of channels. Each channel receives the analog signal from an x-ray sensitive cell and generates digital data indicative of the value of the analog signal.

Abstract: A high voltage low inductance resistor (120) includes a resistor body (122) having a perimeter and a center. A first terminal (126) is located away from the center of the resistor near the perimeter of the body (122). A serpentine resistance element (130) includes a first end (136). A conductive ring (124) is located near the perimeter and circumscribes the serpentine resistance element (130). The ring (124) is electrically connected to the first terminal (126). The first end (136) is electrically connected to the conductive ring (124). A first resistance segment (138a) of the resistance element (130) begins at the first end (136) and extends in a first direction generally around the perimeter of the body (122). An apex (142a) has an input portion (143) and an output portion (145). The apex (142a) redirects the resistance element in a generally opposite direction, the input portion (143) transitioning into the first resistance segment (138a).

Abstract: A dual filament x-ray tube assembly (16) includes an evacuated envelope (52) having an anode (54) disposed at a first end of the evacuated envelope (52) and a cathode assembly (62) disposed at a second end of the evacuated envelope (52). The cathode assembly includes a variable-length filament assembly (72, 74; 100) which emits electron beams for impingement on the anode (54) at focal spots having varying lengths. The cathode assembly (62) further includes a cathode cup (64, 66, 68; 110, 112) which is subdivided into a plurality of electrically insulated deflection electrodes (64, 66, 68; 110, 112). A filament select circuit (80) selectively and individually heats a portion of the variable-length filament assembly (72, 74). Electron beams emitted from the filament assembly (72, 74) are electrostatically focused and controlled by applying potentials to different ones of the deflection electrodes (64, 66, 68; 110, 112).

Abstract: Data collected from a cone beam scanner is reconstructed into a volumetric image representation by defining a plurality of oblique surfaces (44) which are reconstructed into a reconstruction cylinder (C). An interpolator (52) identifies non-redundant rays of radiation which pass through the oblique surfaces. More particularly, rays of radiation that intersect a center point of each oblique surface (70) are identified along with rays tangent to surface rings on each oblique surface (72, 74). Data from the identified non-redundant rays of radiation is weighted by a first data processor (54). A second data processor (56) convolves the weighted data and passes it to a backprojector (58) which backprojects the data into an image memory (60).

Abstract: A magnetic resonance imaging method includes acquiring a baseline magnetic resonance image of a region of interest in the absence of a contrast agent and simulating an increase in image intensity of a subregion of interest within the region of interest which is subject to increased image intensity in the presence of a contrast agent. The magnetic resonance k-space signal intensity is correlated with contrast agent concentration in the subregion and a contrast agent is administered to the subject. As k-space data for the region of interest is acquired, the signal intensity is monitored to derive contrast agent concentration information. When the peak contrast agent concentration is detected from the monitored k-space data signal intensity, the phase encoding is adjusted so that k-space data with zero phase encoding is acquired. In a further aspect, a magnetic resonance imaging apparatus is also provided.

Abstract: A medical imaging system for conducting an image-guided medical procedure on a subject and a method for performing the same is provided. The system includes a medical imaging apparatus, such as a CT scanner, magnetic resonance imaging system, or ultrasonic imaging system, etc., for obtaining volumetric images of the subject. Through intervention planning techniques, an interventional procedure on a subject using the volumetric images is determined. A mechanical arm assembly disposed in proximity to the medical imaging apparatus carries out the interventional procedure. The mechanical arm assembly includes a base support, a distal end, a plurality of arm segments, and a plurality of joints between the arm segments for carrying out the interventional procedure. An end-effector is disposed at the distal end of the mechanical arm assembly. The end-effector includes gripping means for selectively gripping and releasing a surgical instrument during the interventional procedure.

Abstract: In magnetic resonance imaging apparatus employing magnetic gradient fields in a phase-encode and in a read-out direction for spatially encoding excited MR active nuclei in a region of interest of a patient, in which a reduced number of readings in the read-out direction is taken, thereby creating an aliased reduced field of view image, at least two r.f. receive coils are used together with sensitivity information concerning those coils in order to unfold the aliased image to produce a full image while taking advantage of the reduced time of collection of data. In accordance with the invention, sensitivity information is collected at a lower resolution than that at which the image information is collected.

Abstract: A non-selective inversion pulse is applied to a plurality of slices, r.f. resonance in MR active nuclei is excited in each of those slices individually, and the slice excitation order is cycled so that the time for the non-selective inversion pulse to any particular phase-encode gradient of all the slices is the same, the time of the zero phase-encode gradient corresponding to that for zero signal from cerebro spinal or other moving fluids.