176 results about "Compton scattering" patented technology

A Silicon detector for x-ray imaging is based on multiple semiconductor detector modules (A) arranged together to form an overall detector area, where each semiconductor detector module includes an x-ray sensor of crystalline Silicon oriented edge-on to incoming x-rays and connected to integrated circuitry for registration of x-rays interacting in the x-ray sensor through the photoelectric effect and through Compton scattering and for an incident x-ray energy between 40 keV and 250 keV to provide the spatial and energy information from these interactions to enable an image of an object. Further, anti-scatter modules (B) are interfolded between at least a subset of the semiconductor detector modules to at least partly absorb Compton scattered x-rays.

A method and apparatus for detecting radiation including x-ray, gamma ray, and particle radiation for radiographic imaging, and nuclear medicine and x-ray mammography in particular, and material composition analysis are described. A detection system employs fixed or configurable arrays of one or more detector modules comprising detector arrays which may be electronically manipulated through a computer system. The detection system, by providing the ability for electronic manipulation, permits adaptive imaging. Detector array configurations include familiar geometries, including slit, slot, plane, open box, and ring configurations, and customized configurations, including wearable detector arrays, that are customized to the shape of the patient. Conventional, such as attenuating, rigid geometry, and unconventional collimators, such as x-ray optic, configurable, Compton scatter modules, can be selectively employed with detector modules and radiation sources. The components of the imaging chain can be calibrated or corrected using processes of the invention. X-ray mammography and scintimammography are enhanced by utilizing sectional compression and related imaging techniques.

This invention describes a system for generating multiple simultaneous tunable electron and photon beams and monochromatic x-rays for all field simultaneous radiation therapy (AFSRT), tumor specific AFSRT and screening for concealed elements worn on to the body or contained in a container. Inverse Compton scattering renders variable energy spent electron and tunable monochromatic x-rays. It's spent electron beam is reused for radiation with electron beam or to generate photon beam. Tumor specific radiation with Auger transformation radiation is facilitated by exposing high affinity tumor bound heavy elements with external monochromatic x-rays. Heavy elements like directly iodinated steroid molecule that has high affinity binding to estrogen receptor in breast cancer and to iodinated testosterone in prostate cancer or with directly implanted nanoparticles into the tumor are exposed with tuned external monochromatic x-rays for tumor specific radiation therapy. Likewise, screening element's atom's k, l, m, n shell specific Auger transformation radiation generated by its exposure to external monochromatic x-rays is used to screen for concealed objects. Multiple beam segments from a beam storage ring or from octagonal beam lines are simultaneously switched on for simultaneous radiation with multiple beams. The beam on time to expose a tumor or an object is only a few seconds. It also facilitates breathing synchronized radiation therapy. The intensity modulated radiation therapy (IMRT) and intensity modulated screening for concealed objects (IMSFCO) is rendered by varying beam intensities of multiple simultaneous beams. The isocentric additive high dose rate from simultaneously converging multiple beams, the concomitant hyperthermia and chemotherapy and tumor specific radiation therapy and the AFSRT's very low radiation to the normal tissue all are used to treat a tumor with lower radiation dose and to treat a radioresistant and multiple times recurrent tumors that heave no other alternative treatments.

A detector having a collimator in a position at a specific angle with respect to a therapeutic X-ray beam is mounted to selectively detect only scattering radiation in the direction. To three-dimensionally obtain a distribution of places where scattering occurs in a patient body, a detector is rotated during irradiation and scattering radiation is measured from all of directions. After that, a reconstructing process is performed, and a distribution of occurrence of scattering radiation in the subject is three-dimensionally imaged. Since angles and amounts of X-rays scattered by Compton scattering are known theoretically, if scattering radiation at a certain angle can be detected, the number of scattering radiation at other angles can be also estimated. On the basis of the theory, images of distribution of scattering radiation sources are converted to images of distribution of absorption of radiation.

A digital dual-band detector functions as an imaging platform capable of extracting hard and soft tissue images, for example. The detector has a first detector system comprising a first scintillator for converting x-rays from a sample to an first optical signal, and a first detector for detecting the first optical signal in combination with a second detector system comprising a second scintillator for converting x-rays from the sample and passing through the first scintillator to a second optical signal, and a second detector for detecting the second optical signal. The detector can facilitate the implementation and deployment of recent developments and can permit low cost practical deployment in clinical applications as well as biomedical research applications where significant improvement in spatial resolution and image contrast is required. These improvements include an increase of feature detection sensitivity by more than an order of magnitude, simultaneous imaging of soft and hard (or mineralized) tissue at extremely high time resolution that is not limited by detector readout speed, and an increase in the signal to noise ratio of images by reducing the substantial background resulting from Compton scattering.

A radioisotope identification and localization device having at least one radiation detector with three dimensional event localization that utilizes a spatial correlation of projection vectors arising from Compton scattering of gamma ray emissions. Source identification and location is supplied by a reconstruction that searches for solutions with radioactive material of unknown type. Detection, identification and localization does not require full energy deposition. Identification and location of known or unknown radioactive material somewhere in a large active area of interrogation is achieved.

X-ray radiation is transmitted through and scattered from an object under inspection to detect weapons, narcotics, explosives or other contraband. Relatively fast scintillators are employed for faster X-ray detection efficiency and significantly improved image resolution. Detector design is improved by the use of optically adiabatic scintillators. Switching between photon-counting and photon integration modes reduces noise and significantly increases overall image quality.

The invention provides a gamma nuclide fast identification method in a complex radiation field, comprising the following steps: measuring a radiation field to get a gamma energy spectrum; deducting a comprehensive background from the gamma energy spectrum and reducing the noise of the gamma energy spectrum to get a net energy spectrum; determining potential nuclides according to the peak positions in the net energy spectrum; calculating the total net peak area of each potential nuclide; standardizing the total net peak area of each potential nuclide to get the standardized total net peak area of the potential nuclide; deducting a Compton scattering background from the standardized total net peak area of each potential nuclide to get the pure peak area value of each potential nuclide; calculating the total probability value and the probability standard threshold of each potential nuclide in the radiation field; and calculating the existence probability of each potential nuclide. According to the invention, multiple times of background deduction calculation and standardization are performed on the measured energy spectrum data, and a nuclide can be identified and the existence probability of the nuclide can be calculated quickly based on the total probability value calculated based on the probability statistics principle and the standard threshold calculated by a standard source.

A combined format gamma-ray detector (D) for measuring impinging gamma-rays (10) includes an active upper level coded aperture detector plane member (12) that is suitable for detecting an impinging gamma-ray (10). An active lower level gamma ray detector plane member (14) that is spaced apart from the upper level coded aperture (12) detects an impinging gamma-ray (10). At low gamma-ray energies, the combined format gamma-ray detector device (D) operates as a conventional coded aperture system and at higher gamma-ray energies, the combined format gamma-ray detector device operates as a Compton scattering detector device.

A scintillator crystal (26)=based gamma-ray camera system is described. The gamma-ray camera system includes a spectra processing component for (34) providing improved energy resolution over that seen in conventional gamma-ray camera systems. The spectra processing component operates to deconvolve detector response functions from observed energy spectra on a pixel by pixel basis. The pixel dependent to detector response functions are obtained by a combination of theoretical simulation, and empirical calibration. By deconvolving pixel specific detector response functions, variations in response of a gamma-ray camera system across its image plane can be accounted for. This offers significant improvements in energy resolution and many of the problems associated with conventional gamma-ray camera systems are reduced. For example, the improved energy resolution allows better rejection of photons associated with Compton scattering events occurring in a source being imaged. This is because a narrower energy window filter can be used without rejecting a significant fraction of non-Compton scattered photons. The spectra processing component can be easily implemented with different types of gamma-ray imagers, for example Anger-type cameras, and may also be retroactively fitted to existing gamma-ray camera systems.

The invention provides a method for rebuilding an image of positron emission tomography. The method includes that a probability model of scattering photon example projection described by appointed model parameters is established according to the operating principle of scattering photon example projection of Compton scattering; a spread function of scattering photon example dot is established according to the probability model of scattering photon example projection; a spread function of non-scattering photon example dot is established according to the probability model of scattering photon example projection and the spread function of scattering photon example dot; and by means of iterative reconstruction algorithm, a PET (positron emission tomography) image is rebuilt by scattering photon example and non-scattering photon example according to the spread function of scattering photon example dot and the spread function of non-scattering photon example dot. According to the method, detection efficiency can be improved, in clinical application, the radiation dosage bore by a detected object and an operator is substantially reduced, detection time is shortened, using efficiency is improved, data sampling is perfected, detector structure is simplified, and cost of the detector is reduced.

A radiation therapy patient couch top which provides optimal fields of treatment in a high-energy radiation therapy environment. In addition, the patient couch top provides superior imaging qualities when used in a diagnostic imaging x-ray environment. All metal is eliminated from the treatment / imaging area. This ensures that no metal will be in the way of the radiation treatment beam and that no artifacting will occur when used with diagnostic imaging techniques such as Computed Tomography. By employing moveable fiber reinforced support beams, the main patient support structure can be positioned so that a minimum of electron generation will occur through Compton scattering. By allowing for a removable insert, the top patient surface can be optimized for treatment, diagnostic imaging or the addition of other useful features. The novel design of these inserts allows the tip end of the beams to be free from any cross members, further improving the imaging and treatment qualities of the resulting patient couch top. Further, a CT simulator insert is provided which provides the same dosimetric properties for the patient couchtop and devices during patient treatment planning.

A system for generating a tunable X-ray pulse comprises a first electron beam source configured to direct a first electron pulse of predetermined energy and pulse length towards a first interaction zone, a laser beam source configured to direct a first photon pulse of predetermined energy and pulse length towards the first interaction zone to interact with the first electron pulse. The first interaction produces a substantially monochromatic second photon pulse of higher photon energy directed towards a second interaction zone, and a second electron beam source configured to direct a second electron pulse of predetermined energy and pulse length towards the second interaction zone so that the second interaction produces an X-ray pulse of predetermined energy and pulse length in a cascaded inverse Compton scattering (ICS) configuration.

A rigid patient support element that is substantially transparent to high energy x-radiation comprising a structural core and one or more perforated face sheets attached to at least one of the top side or bottom side of the element. The support element reduces Compton scattering thereby reducing patient skin damage. The support element of the present invention can be integrated into a patient support surface, used as an insert or used as a spacer and easily removable from a patient support surface.

The intrinsic background of a gamma ray spectrometer is significantly reduced by surrounding the scintillator with a second scintillator. This second (external) scintillator surrounds the first scintillator and has an opening of approximately the same diameter as the smaller central scintillator in the forward direction. The second scintillator is selected to have a higher atomic number, and thus has a larger probability for a Compton scattering interaction than within the inner region. Scattering events that are essentially simultaneous in coincidence to the first and second scintillators, from an electronics perspective, are precluded electronically from the data stream. Thus, only gamma-rays that are wholly contained in the smaller central scintillator are used for analytic purposes.

A method and an apparatus for liquid safety-detection by backscatter with a radiation source relate to a radiation detecting technology field. The invention comprises using a radiation source, a collimator, a detector, a data collector and a computer data processor, and has the main steps of: 1) a liquid article to be detected being placed onto a rotatable platform; 2) the ray emitted from the radiation source causing Compton scattering at the surface of the liquid after passing through the package layer of the liquid article; 3) the scattering photons being received by the detector after passing the collimator; 4) the detector transmitting the received data to the data collector; and 5) the data collector transmitting the amplified and shaped data to the computer data processor, which processes the data to obtain the liquid density of the detected article, then compares the result with the densities of dangerous articles in a current database, and gives warning if finding that the density of the detected article is consistent with that of a dangerous article. Comparing to the prior art, the invention has a convenient use, a rapid and accurate detection, a strong anti-interference, a high use safety and reliability, and an easy protection.

An omni-directional sensor device is provided for detecting radiation emission sources, such as nuclear and atomic weapons and dirty bombs. The omni-directional sensor device is constructed as a three-dimensional structure formed of a plurality of walls of gamma ray detector arrays. The walls face in multiple directions to establish omni-directional sensing of incident gamma rays from substantially all directions. As constructed, a first wall of the device intercepts an incident gamma ray at a first location. The gamma ray experiences a Compton scattering effect whereby a deflected gamma ray is emitted into the inner chamber of the device before intercepting a second wall of the device at a second location. The first and second locations can be used to trace the location of the emission source. Also provided are radiation detection systems including the omni-directional sensor devices, and methods of locating a radiation emission source.

A neutron source illuminates suspect material leading to emission of gamma rays characteristic of the isotopes present. The system measures Compton scattering of emitted gamma rays using detectors with three dimension event localization capability. Detection does not require full energy deposition. A spatial correlation of projection vectors is computed by a reconstruction that searches for solutions that generate spatial correlation. Identification and location for contraband material is determined from solutions that generate spatial correlation.

Provided are new methods for enhancing the selection of true (T) annihilation events relative to the inclusion of true scattered (TS) and random (R) annihilation events in PET tomographs and thereby improving the sensitivity and / or resolution of PET scanners. The methods include reconstruction of Compton scattering interactions in the γ-ray detectors for determining the angles of incidence of the γ-rays received at the detectors and may utilize γ-ray polarization effects and electron recoil data associated with positron annihilation and Compton scattering. The use of the γ-ray polarization effects provides an improved ability for selecting data corresponding to T events while simultaneously suppressing data corresponding to TS and R events during PET applications.

A method for detection of ionizing radiation comprises the steps of (i) directing ionizing radiation towards an object to be examined; (ii) preventing Compton scattered radiation, preferably at least 99% of the radiation Compton scattered in said object, from being detected; and (iii) detecting ionizing radiation spatially resolved as transmitted through said object to reveal a spatially resolved density of said object, wherein said ionizing radiation is provided within a spectral range such that more, preferably much more, photons of said ionizing radiation are Compton scattered than absorbed through the photoelectric effect in said object to thereby reduce the radiation dose to said object.

The invention discloses a ray back scattering imaging system for discriminating depth information. The system comprises a ray source, a first collimating device, a plurality of groups of detectors, a plurality of second collimating devices and at least one light barrier. The relative positions of the ray source and the groups of detectors are adjusted, restriction of second collimating devices and the light barrier is adjusted, detection geometrical angles of the groups of detectors are different, strength differences of back scattering rays collected by detection units at responding positions of different groups of detectors are compared, and the depth information that rays are subjected to Compton scattering effect in an object to be detected is determined. Strength differences of back scattering rays collected by detection units at different positions of the same group of detectors are compared, and transverse information that rays are subjected to Compton scattering effect in the object to be detected is obtained. Through the relative motion formed by an integral body which is formed by the ray source and the groups of detectors and the object to be detected, the continuous sweeping is conducted, and integral multi-layer back scattering images are obtained.

Provided are a gamma ray detector and a gamma ray reconstruction method which can be used in SPECT and PET and which combine and reconstruct the information on “Compton-scattered” gamma rays, thereby remarkably increasing gamma ray detection sensitivity, decreasing the amount of a radioactive substance given to a subject, and remarkably reducing the concern about the amount of radiation exposure. The gamma ray detector comprises an absorber scintillator 12 made from an absorptive substance exhibiting a high rate of absorption with respect to gamma rays 1 in an energy region, emitted from a subject, a Compton scattering scintillator 14 made from a Compton scattering substance exhibiting a high probability of Compton scattering, and an energy detector 16 which combines the amounts of gamma ray energy absorption simultaneously measured by the two types of scintillators to reconstruct the gamma rays emitted from the subject. The two types of scintillators 12 and 14 are arranged in multiple layers so as to absorb or Compton-scatter the whole energy of the gamma rays 1.