Abstract: A system for detecting and graphically displaying a contents of a fast-moving target object comprises: a radiation source, having a position such that at least a portion of radiation emitted from the radiation source passes through the fast-moving target object, the fast-moving target object having a variable velocity and acceleration while maintaining a substantially constant distance from the radiation source and being selected from the group consisting of: a vehicle, a cargo container and a railroad car; a velocity measuring device configured to measure the variable velocity of the fast-moving target object; a detector array comprising a plurality of photon detectors, having a position such that at least some of the at least a portion of the radiation passing through the target object is received thereby, the detector array having a variable count time according to the variable velocity and a grid unit size; a counter circuit coupled to the detector array for discretely counting a number of photons enterin

Abstract: A method and system for normalization of a positron emission tomography system is provided. The method includes acquiring three-dimensional normalization scan data from a positron emission tomography system with at least one septum and determining a down-sampling factor based in part on the configuration of the at least one septum. The method further includes modifying the three-dimensional normalization scan data using the down-sampling factor.

Abstract: The invention relates to a system and method for generating a detector position map for an array of detectors. The detector position map comprises a map which converts measured position coordinates from a detection event to the detector in the array which detected the detection event. The method comprises the steps of illuminating an array of detectors with a source of radiation to generate a histogram, the histogram comprising an event count as a function of two dimensions, the two dimensions corresponding to a face of the array of detectors, wherein the histogram comprises a plurality of first peaks; modifying the histogram to comprise a plurality of second peaks, wherein the second peaks have a greater degree of isolation from each other than the first peaks; and for each detector, determining a region on the detector position map which corresponds to the detector, each region being based on a position of one of the second peaks.

Abstract: The present invention provides methods and apparatuses for constructing observed data from a Compton camera in order to provide a three-dimensional image of a radiopharmaceutical source distribution within a patient. No intermediate two-dimensional images are formed. Observed data may be analyzed by a processor in order to construct a three-dimensional image representing the source distribution. An idealized mathematical model may express the observed Compton camera data in terms of an integral over the source distribution. An exact analytic inversion is then found for this idealized model. The new analytic solutions arise from a generalization of the integral equation used to model the Compton camera. The kernel of the integral equation is modified by the introduction of an index p that describes the effect of source distance from the camera.

Abstract: A method of quantitative positron emission analysis includes accounting for the loss of positron-electron annihilation events and quantitative inaccuracies in positron emission assays.

Abstract: The invention concerns a network system for radiographing radiation images. The network system includes a plurality of radiation-image reading apparatus to read the radiation images stored in radiation-image storing sheets, so as to generate image data sets each of which corresponds to each of the radiation images, and a plurality of controllers to register discrimination information sets each of which corresponds to each of the radiation-image storing sheets. Each of the controllers can display a radiation image for confirmation, when it receives an image data set corresponding to the radiation image. A radiation-image reading apparatus reads a discrimination information set recorded on a radiation-image storing sheet loaded into the radiation-image reading apparatus.

Abstract: A method of localizing a scintillation event in a scintillation camera is disclosed.

Abstract: Methods and apparatuses for obtaining position and energy information without pileup. Signal integration, which is triggered by a present event, stops when a subsequent event is detected. A weighted value for estimating the total energy in a scintillation is calculated, which includes the energy of the current event and a residual energy from previous events. Remnant correction is used to calculate a pile-up free energy from two consecutive weighted values. An analog filter may be applied to reduce noise. Dynamic digital weighting of integrated values, and/or digital integration may be used during data processing. Pileup can be avoided in conjunction with several types of applications, including multi-zone detector applications and coincidence detection applications. High-resolution timing techniques are also disclosed that facilitate one's ability to avoid pileup.

Abstract: A gamma camera system is described in which multiple simultaneous acquisitions are performed based upon different characteristics for event data acquired by a common gantry behavior. The event data from a detector is selected for different images based upon characteristics such as gating, ungated, energy windows, or zooming.

Abstract: An apparatus (1) for irradiating material comprises a single UV, pulsed brigth white light or IR lamp (2) with a centrally disposed receptacle (3) for containing material to be irradiated. The lamp can be an elongate hollow tube (2) of annular construction. Internal formations may be present within the lamp to control the position of the arc. For example, the lamp may have a plurality of longitudinal segments arranged such that a discharge arc is formed within each segment or internal formations may be provided to direct the position of the arc within the lamp. A pump (36) may be included for moving material through the receptacle which is preferably the hollow area within the annulus of the elongate hollow tube. Material can be treated batchwise or in a continuous process. This apparatus is suitable for the sterilisation of biological and/or non-biological materials. A further use is in carrying out photolysis on chemical substances in photochemical reactions.

Abstract: A method and apparatus for on-line DOI rebinning for LSO PET/SPECT to improve spatial resolution, for use in a hybrid Positron Emission Tomography (PET)/Single Photon Emission Computed Tomography (SPECT) system running in PET-mode. Data acquisition hardware is used to feed a detector pair coincidence event stream to an on-line rebinner. Gamma centroid location measurements are made by rastering assumed transaxial and radial head positions and the corresponding rebinning maps for optimal back-projected image resolution. Optimal positions are found by collecting a 64-bit list mode file, assuming a crystal position as the centroid for each of the heads, defining a sequence for varying the assumed positions, making the rebinning look-up tables, rebinning the list mode data, histogramming and reconstructing the image, assessing the image resolution, recording the best resolution number and the associated trial position variables, repeating these on the next trial variable set.

Abstract: A gamma camera system having a small field of view that includes a plurality of modules, a module support board on which the modules are mounted, a module interface board, signal amplifier and detection logic mounted on the module support board, a computer interface board mounted in a computer and connected to an internal bus in the computer, and a serial connection between the module support board and the computer interface board. Each module includes a scintillation crystal array, a photodiode array coupled to the scintillation crystal array, a first PETRIC circuit coupled to the array of photodiodes in parallel to determine the crystal of highest peak analog signal and its address in the array and provide an output thereof. A second PETRIC circuit receives the analog outputs of the first PETRIC circuits and determines the crystal of the highest peak analog signal of all the modules and its address in the arrays and provides an output thereof.

Abstract: The present invention provides methods and apparatuses for constructing observed data from a Compton camera in order to provide a three-dimensional image of a radiopharmaceutical source distribution within a patient. No intermediate two-dimensional images are formed. Observed data may be analyzed by a processor in order to construct a three-dimensional image representing the source distribution. An idealized mathematical model may express the observed Compton camera data in terms of an integral over the source distribution. An exact analytic inversion is then found for this idealized model. The new analytic solutions arise from a generalization of the integral equation used to model the Compton camera. The kernel of the integral equation is modified by the introduction of an index p that describes the effect of source distance from the camera.

Abstract: A method for temperature compensation of sensitivity of an image including photosensitive spots each with a photodiode connected to read circuits. The photosensitive spots are divided into detecting photosensitive spots, detecting an image when exposed to information carrying the image and sensitive to this information, and into blind spots protected from the information. When the photosensitive spots are taken to a reference temperature, an average leakage current in the photodiodes of the blind photosensitive spots is calculated and a first average is generated from signals from the blind photosensitive spots during a read operation. When the photosensitive spots are taken to an ambient temperature to be determined, another average is generated from signals from the blind photosensitive spots during another read operation. The ambient temperature is calculated from the average leakage current and from the distance between the two averages.

Abstract: The invention relates to a method for restoring a signal of a defective channel of a beam detector, which has a multitude of channels and by means of which projections are recorded from different directions of projection. The channels of the beam detector each have a detector element with channel electronics connected downstream therefrom. The signal of the defective channel is restored while using neighboring signals of an M-neighborhood of the same projection and from adjacent signals of an M-neighborhood of additional projections.

Abstract: The present invention is directed to a system and method for efficiently and cost effectively determining an accurate depth of interaction for a crystal that may be used for correcting parallax error and repositioning LORs for more clear and accurate imaging. The present invention is directed to a detector assembly having a thin sensor (e.g., APD) deployed in front of the detector (the side where the radioactive source is located and the photon is arriving to hit the detector) and a second sensor (APD or photomultiplier) on the opposite side of the detector. The light captured by the two interior and exterior sensors which is proportional to the energy of the incident photon and to the distance where the photon was absorbed by the detector with respect to the location of the two sensors, is converted into an electrical signal and interpolated for finding the distance from the two sensors which is proportional to the location where the photon hit the detector.

Abstract: A method of applying scatter and attenuation correction to emission tomography images of a region of interest of a patient under observation comprises the steps of aligning a three-dimensional computer model representing the density distribution within the region of interest with the emission tomography images. The computer model is created from image data of other subjects thereby to avoid the need to image the subject under observation to create the computer model. Scatter and attenuation correction is applied to the emission tomography images using the aligned computer model as a guide.

Abstract: A gamma camera system is described having a user interface by which protocols can be set up for the simultaneous acquisition of different views. Pull-down menus prevent the selection of incompatible simultaneous views for acquisition. The protocol being assembled, including its sequential steps and multiple simultaneous views, are displayed to the user.

Abstract: A nuclear camera system includes a detector (12) for receiving radiation from a subject (14) in an exam region (16). The detector (12) includes a scintillation crystal (20) that converts radiation events into flashes of light. An array of sensors (22) is arranged to receive the light flashes from the scintillation crystal (20). Each of the photomultiplier sensors (22) generates a respective sensor output value in response to each received light flash. A processor (26) determines when each of the radiation events is detected. At least one of an initial position and an energy of each of the detected radiation events is determined in accordance with respective distances (d1 . . . d19) from a position of the detected event to the sensors (22). An image representation is generated from the initial positions and energies.

Abstract: A method and apparatus for on-line DOI rebinning for LSO PET/SPECT to improve spatial resolution, for use in a hybrid Positron Emission Tomography (PET)/Single Photon Emission Computed Tomography (SPECT) system running in PET-mode. Data acquisition hardware is used to feed a detector pair coincidence event stream to an online rebinner. Gamma centroid location measurements are made by rastering assumed transaxial and radial head positions and the corresponding rebinning maps for optimal back-projected image resolution. Optimal positions are found by collecting a 64-bit list mode file, assuming a crystal position as the centroid for each of the heads, defining a sequence for varying the assumed positions, making the rebinning look-up tables, rebinning the list mode data, histogramming and reconstructing the image, assessing the image resolution, recording the best resolution number and the associated trial position variables, repeating these on the next trial variable set.

Abstract: A method of localizing a scintillation event in a scintillation camera is disclosed.

Abstract: A time interval to voltage converter with very low nonlinearity for time stamping events. The converter automatically selects one of two clocks related to a reference clock and ensures that the time between an event edge to a clock edge is sufficiently large to properly operate a switch and yield very linear time-to-voltage conversion.

Abstract: An apparatus and method for determining the total energy of a continuously under-sampled energy signal resulting from an annihilation event detected by a positron emission tomograph (PET) scanner. An annihilation event is detected by a scintillator crystal and photomultiplier tube, which produces an energy signal that is continuously under-sampled by an analog-to-digital converter. The start time of the energy signal is determined by a constant fraction discriminator and time-to-digital converter. The start time is used to calculate a new amplitude for each sample, from which the total energy can be calculated.

Abstract: An apparatus and method for determining the total energy of a continuously under-sampled energy signal resulting from an annihilation event detected by a positron emission tomograph (PET) scanner. An annihilation event is detected by a scintillator crystal and photomultiplier tube, which produces an energy signal that is continuously under-sampled by an analog-to-digital converter. The start time of the energy signal is determined by a constant fraction discriminator and time-to-digital converter. The start time is used to calculate a new amplitude for each sample, from which the total energy can be calculated.

Abstract: A nuclear camera system is provided in which the energy spectrum peaks identified by a camera detector head are automatically adjusted to account for drift and other sources of inaccuracy. Histograms of events detected by the photomultiplier tubes of the detector head are acquired continuously and updated periodically. A system operator initiates the adjustment with an autopeaking command which causes the system to ascertain the validity of the histogram data and, if it is valid, to determine a peak energy level. The determined level is compared to a theoretical value for an isotope present and the comparison is used to adjust the gain applied to energy data of the detector head.

Abstract: The present invention provides a high gain collimator producing generally uniform intensity profiles for use in lithography and other applications. A focusing optic is also provided. The collimator includes a reflector and guide channel. The guide channel preferably includes polycapillary tubes and/or microchannel plates. The polycapillary tubes are used to collimate or focus the central portion of the x-ray beam in a circular, elliptic, square, or rectangular shape. A conical, parabolic resonance reflector or grazing incidence reflector with a shape similar to the polycapillary collimator is used to increase the solid angle collected and produce a circular, square, etc. annular x-ray beam whose inside dimensions are approximately equal to the exit dimensions of the polycapillary collimator.

Abstract: An image detector using arrays of photodiodes, and in particular to a radiological image detector. In the image detector, all the photodiodes of one and the same array are linked to adapter amplifiers embodied in the form of at least one integrated circuit. In each integrated circuit, an adapter amplifier, to which no photodiode is linked, delivers a voltage serving as a reference to define a bias voltage to be applied to the photodiodes. This arrangement makes it possible in particular to associate photosensitive arrays with amplifiers exhibiting different voltage thresholds.

Abstract: A scintigraphic device, comprising a collimator, a scintillation crystal structure, a plurality of photomultipliers, electronic circuits for the determination of the position co-ordinates (XY) and energy of the event and their amplification for their subsequent transfer to an electronic processor, wherein photomultipliers (31, 32, 33, 3n) are positioned mutually adjacent, each provided with its own independent electronic circuits (121, 122, 123, 12n), and a circuit (13) for interrogating the respective synchronism signals drawn from the respective electronic circuits (12) determines the signal indicating the photomultiplier (13) that detected the event and enables only a corresponding analogue switch (14) to transfer the signals carrying the position co-ordinates of the event from the enabled electronic components (12) to an analog to digital converter (A/D).

Abstract: A nuclear camera system includes a detector (12) for receiving radiation from a subject (14) in an exam region (16). The detector (12) includes a scintillation crystal (20) that converts radiation events into flashes of light. An array of sensors (22) is arranged to receive the light flashes from the scintillation crystal (20). Each of the photomultiplier sensors (22) generates a respective sensor output value in response to each received light flash. A processor (26) determines when each of the radiation events is detected. At least one of an initial position and an energy of each of the detected radiation events is determined in accordance with respective distances (d1 . . . d19) from a position of the detected event to the sensors (22). An image representation is generated from the initial positions and energies.

Abstract: A method of imaging by means of ionizing radiation in which a first measurement f1 is performed by integrating a detection signal generated by each detection cell of an ionizing radiation detector while simultaneously making a second measurement f2 by counting ionizing rays, and then an estimate of the flux is calculated, in particular by using the formula f=&agr;·f1+(1−&agr;)·f2 where &agr; is an increasing function over the range 0 to 1 of a first estimate fe of the flux f, which first estimate is established as a function of at least one of the first and second measurements f1 and f2.

Abstract: A nuclear camera system includes a detector (12) for receiving radiation from a subject (14) in an exam region (16). The detector (12) includes a scintillation crystal (20) that converts radiation events into flashes of light. An array of sensors (22) is arranged to receive the light flashes from the scintillation crystal (20). Each of the photomultiplier sensors (22) generates a respective sensor output value in response to each received light flash. A processor (26) determines when each of the radiation events is detected. At least one of an initial position and an energy of each of the detected radiation events is determined in accordance with respective distances (d1 . . . d19) from a position of the detected event to the sensors (22). An image representation is generated from the initial positions and energies.

Abstract: A gamma camera system and method are described which use multiple point sources to detect inaccuracies in detector translational and rotational alignment. In practice of the method of the preferred embodiment, three capillary tubes, each containing a drop of an isotope, are located in different planes and locations with respect to the axis of rotation of the detectors. A SPECT acquisition is performed and the point source projection data is processed to calculate the point source coordinates, from which center-of-rotation correction factors may be calculated. These correction factors are applied by mechanical and software adjustments to the gantry and acquisition systems of the camera to correct for both translational and rotational inaccuracies.

Abstract: A method and system for intelligent control of external devices using a mammalian brain-like structure having three parts. The method and system include a computer-implemented neural network system which is an extension of the model-based adaptive critic design and is applicable to real-time control (e.g., robotic control) and real-time distributed control. Additional uses include data visualization, data mining, and other tasks requiring complex analysis of inter-relationships between data.

Abstract: A gamma camera system that increases the count rate by counting events that time-wise appear to be pile-up events but are spatially separated.

Abstract: In a method and filter and computer product for adaptive filtering of projection data acquired by a medical diagnostic apparatus, raw data-based filtering of the acquired projection data is undertaken using a filter with a filter kernel having a constant filter width, and the filtered projection data are mixed with the acquired projection data with a fixing of the respective quantitative relationships of filtered projection data to acquired projection data ensuing dependent on respective subsets of the acquired projection data.

Abstract: A nuclear camera system is provided in which the energy spectrum peaks identified by a camera detector head are automatically adjusted to account for drift and other sources of inaccuracy. Histograms of events detected by the photomultiplier tubes of the detector head are acquired continuously and updated periodically. A system operator initiates the adjustment with an autopeaking command which causes the system to ascertain the validity of the histogram data and, if it is valid, to determine a peak energy level. The determined level is compared to a theoretical value for an isotope present and the comparison is used to adjust the gain applied to energy data of the detector head.

Abstract: A device for determining the photon energy E1 and direction cone angle of incident gamma ray includes a radiation detector for receiving an incident gamma ray having an unknown photon energy E1 and an unknown direction and for scattering the gamma ray with two Compton scattering interactions and a subsequent scattering or absorption interaction. The detector provides three outputs, each output corresponding to one of the Compton scattering and the subsequent scattering or absorption interactions, to a processor, which is programmed to calculate the photon energy E1 and direction cone angle of the incident gamma ray based on these outputs.

Abstract: Gamma cameras and positron (PET) cameras use scintillation detectors to detect radiation from the body. However, when the number of radiation particles that strike the detector is very high, the chance that signals from two or more individual particles will pile up in the detector (to produce one erroneous, larger signal) is high. This problem is common to all applications using scintillation detectors. The present invention discloses methods and apparatus to prevent and correct for this problem. Results from a circuit according to the present invention show at least a 10 fold improvement in the maximum detection-rate limit over the conventional method.

Abstract: A nuclear medicine imaging device includes a radiation camera (10) including a plurality of photo multiplier tubes (28). Each photo multiplier tube (28) is configured with an analog to digital converter (30) which converts a detected scintillation event (50) to sampled digital values. A storage device (66) is preloaded with an estimator function which can be derived from a calibration scintillation events. A processor (14) in communication with both the camera (10) and the storage device (66), detects an event and combines the digital values which are sampled together to arrive at a total area or energy of the scintillation event. Alternately, if a second pulse (52) is detected before the first scintillation event (50) has ended, the area combining (A1) of the first event is stopped and a pulse tail is estimated (A2) from the estimator functions stored. This estimated tail is then added to the combined data values taken until the time of pile-up.

Abstract: A radiation detector, in particular a gamma camera, is constructed and operated in such a fashion that only a predetermined number of light sensors (such as PMT's) adjoining each other in a cluster are used to generate a signal with amplitude and event position information. The camera may also use an array of individual scintillation elements (crystals) in place of a single crystal, with certain advantages obtained thereby. According to another aspect of the invention, there is a reflector sheet that defines an array of apertures through which scintillation light can pass from the scintillation crystal to a plurality of light sensors optically coupled to an optical window in an array corresponding to the array of apertures in the reflector.

Abstract: A method and apparatus for improving the image quality of positron emission tomography is disclosed. This is achieved by analyzing individual photomultiplier tubes for true events. The apparatus includes a photomultiplier tube for generating a photomultiplier tube signal. A series of pull up resistors generates a code signal identifying the photomultiplier tube. A clock generates a time stamp to the photomultiplier tube signal. A bus buffer generates an encoded signal. A position computing device calculates the position of the photomultiplier tube. An image computer generates an image from a plurality of encoded signals. A display displays the image. Analyzing data from individual photomultiplier tubes results in smaller areas and smaller amounts of data to be processed. This then permits smaller time frame windows to be used. The use of time stamps also permits data before and after an event to be recorded.

Abstract: A method and apparatus for improving the sensitivity of a position sensitive gamma ray detector and gamma camera. To obtain good position resolution, small effective detector elements are required. However, such small detector elements cause nearly all the gamma rays interacting by Compton scattering to be lost, i.e., they will not contribute to forming the image. The method and apparatus of the present invention takes advantage of the fact that when an incoming gamma ray of known energy is completely absorbed in two separate detector elements the sum of the energy depositions identifies this gamma ray as a valid event. Furthermore, for incoming gamma rays having energies less than 511/2 keV the position where the smallest energy is deposited is the first interaction site and therefore this position can also contribute to forming the image. Alternatively, both interaction sites can be used to form the image, thus improving sensitivity but increasing background noise compared with the preferred embodiment.

Abstract: A gamma camera system is described in which multiple simultaneous acquisitions are performed based upon different characteristics for event data acquired by a common gantry behavior. The event data from a detector is selected for different images based upon characteristics such as gating, ungated, energy windows, or zooming.

Abstract: A radiation detection and discrimination device includes a radiation sensor and signal processing circuitry. The radiation sensor includes a LiBaF3 scintillator configured to simultaneously detect presence of a first type of radiation and a second type of radiation. The radiation sensor generates an output signal for each type of detected radiation. The signal processing circuitry communicates with the sensor, and includes data analysis circuitry and memory. The signal processing circuitry is operative to receive at least one output signal from the sensor. The memory is operative to store at least one predetermined indicia characterizing membership of an output signal within a group comprising a unique type of radiation. The data analysis circuitry compares the output signal with the at least one predetermined indicia to determine membership of the output signal within one group of a plurality of unique groups.

Abstract: A method and apparatus for improving the sensitivity of a position sensitive gamma ray detector and gamma camera. To obtain good position resolution, small effective detector elements are required. However, such small detector elements cause nearly all the gamma rays interacting by Compton scattering to be lost, i.e., they will not contribute to forming the image. The method and apparatus of the present invention takes advantage of the fact that when an incoming gamma ray of known energy is completely absorbed in two separate detector elements the sum of the energy depositions identifies this gamma ray as a valid event. Furthermore, for incoming gamma rays having energies less than 511/2 keV the position where the smallest energy is deposited is the first interaction site and therefore this position can also contribute to forming the image. Alternatively, both interaction sites can be used to form the image, thus improving sensitivity but increasing background noise compared with the preferred embodiment.

Abstract: An apparatus, methods, and systems for assaying materials are disclosed using a combination of detectors that scan for areas of material non-uniformity, and assay the type and amount of radioactivity present in the material. Scanning detectors are provided to scan for non-uniform levels of radiation emanating from the material. If any non-uniformity is detected by the scanning detectors, the material non-uniformity is removed and handled with radioactive material protocols. The remaining material may then be subject to assay. If the material shows no signs of non-uniform radiation emission, the assay detectors are used to assay the material. If the concentration of any one or more radionuclides exceeds a predetermined limit, the assayed material is handled with radioactive material protocols.

Abstract: A nuclear medicine imaging system includes the capability to correct for the deadtime, including the capability to correct for spatial variations in deadtime across the imaging surface of a detector. The imaging system includes one or more radiation detectors, each using a large, monolithic scintillation crystal. Each detector has deadtime associated with it. A given detector is used to acquire an energy profile of a patient based on emission radiation. The detector includes a number of timing channels. The energy profile is used to select a zone influence map indicating the extent of spatial overlap in response between the various timing channels. Emission data of the patient is then acquired during an emission scan. During acquisition of the emission data, a rate meter assigned to each timing channel samples the number of counts associated with each timing channel to acquire deadtime data.

Abstract: A coded aperture is placed in proximity of a patient's body and a 2D coded image is acquired in conventional manner. The basic data-acquisition geometry is similar to that used in various coded-aperture systems. According to one aspect of the invention, additional coded images are acquired with different spacings between the aperture and the detector. Alternatively, additional coded images could be acquired with multiple movable apertures or by varying the location of the aperture relative to a patient. Another aspect of the invention resides in the recognition that presently available computer algorithms can process these multiple coded images in such a way as to estimate the integrals of the 3D object over a set of parallel cylindrical tubes extending through the volume of the target object. Such “tube integrals” can be thought of as the output of an ideal collimator where the sensitivity is confined to a tubular region of constant cross-section.

Abstract: There is provided a radiation detector capable of discriminating a kind of rays in radiation. The radiation detector includes a scintillator and a discriminator. The scintillator scintillates depending on the type of radiation and generates a first output signal and second output signals after the first output signal. The second output signals vary the signal pattern thereof with a kind of rays in radiation. The discriminator discriminates a kind of rays in radiation based on the first signal and the second signals. The scintillator has multiple scintillation characteristics, and includes Gd2O2S (GOS) or Y2O2S (YOS), for example.

Abstract: In a preferred embodiment, a method of digitally de-randomizing pulses in a radiation spectroscopy system, the method including the steps of: receiving an input signal representative of a radiation detector output; analyzing the input signal to derive separate event samples and background samples; storing the event samples and the background samples; and reading stored event samples and background samples and adjusting spacing in time between adjacent event samples such that the event samples are spaced apart a time interval at least equal to pulse processing time of elements receiving an output of spaced apart event samples and the background samples.