70results about "Photographic dosimeters" patented technology

The invention provides a radioactive substance detection method, a radioactive substance detection device and a radioactive substance detection system based on a gamma camera. The detection method comprises the following steps of: receiving gamma photons incident from all directions of a target angle plane (alpha, beta) defined by radioactive substances by using the gamma camera; generating gamma photon energy spectrums and projection data of the radioactive substances; and reconstructing the projection data by using a 'maximum likelihood estimation' statistical iterative algorithm to obtain a gamma radiation image with quantitative information. By the method, the spatial resolution and the signal to noise ratio of the gamma radiation image are increased, spaces of the radioactive substances are positioned, the radiation dose is measured, nuclide types of the radioactive substances are identified, and the radioactive activity is measured.

Devices and methods for the characterization of areas of radiation in contaminated rooms are provided. One such device is a collimator with a collimator shield for reducing noise when measuring radiation. The determination system uses a radiation detector comprising a plurality of overlapping layers of radiation sensitive film interspersed with adjacent layers of an attenuator material. The resulting sandwich of the stacked film layers and attenuator layers provides a useful detector. The detector can be used within a radiation detector apparatus having a collimator to enable a 360 degree field of view of radiation sources within a room or enclosed environment.

The invention brings forward a method and device for measuring two-dimensional angle distribution of the radiation dose rate of a radioactive substance. The method comprises: a gamma camera detecting gamma photons incident from each direction of a defining object angle plane in an object area, and respectively recombining to form projection data and power spectrum data; reconstructing the projection data by use of an image reconstruction algorithm to obtain a radiation gamma image; based on this, obtaining the two-dimensional angle distribution of the fluence rate of the gamma photons incident from each direction in the object area; and according to incident photon energy, searching for corresponding conversion coefficients, and by use of the conversion coefficients, converting the two-dimensional angle distribution of the fluence rate of the gamma photons into the two-dimensional angle distribution of the dose rate of radiation of the radioactive substance to the position of the gamma camera. The measuring method provided by the invention realizes measurement of the two-dimensional angle distribution of the radiation dose rate of the gamma photons incident from the different directions in the object area by use of such devices as the gamma camera and the like.

A method for creating a volumetric data set representing a three-dimensional distribution, such as a dose distribution produced by a radiosurgery system uses a plurality of stacked sensors (12) to obtain two-dimensional cross sectional images of the distribution. The images are optically scanned in a scanner (20) to obtain digitized two-dimensional images which can be processed by software in a computer (22). Each of the sensors (12), which may be, for example, a sheet of X-ray sensitive film, is marked with a visible fiducial mark (17). The software locates images of the fiducial marks (17) in the digitized images. The locations of the fiducial marks (17) indicate the proper orientation and sequence of each image. The software populates a volumetric data structure with data from the scanned images. Interpolation may be used to increase the resolution of the data structure. The system is not susceptible to errors which might be caused by images of the sensors being inverted or mis-aligned before or during scanning.

The invention provides a calculating method for the exposure index in a digital X-ray mammography system. The method includes the steps that the linear coefficient between the dosage value of a dosimeter and the gray level average value of each photo is calculated first, the interesting value in a mammary gland region in each photo is calculated, and the exposure index is calculated according to the interesting value and the linear coefficient, so that the calculated exposure index is accurate, and a doctor can adjust the exposure parameter conveniently to obtain high-quality images and reduce the misdiagnosis rate. The invention further provides a calculating method for the deviation index in the digital X-ray mammography system.

A radiation dosimetry method and associated devices for carrying out the method are disclosed herein. More particularly, a method and associated apparatus which compensates for variations in amounts of a radiation sensitive material in a radiation dosimetry film is provided.

In the case where radiological imaging of a subject to be injected with a contrast agent is performed continuously and a radiation exposure dose of the subject due to the continuous radiological imaging is obtained based on a radiation image signal of each frame detected by a radiation image detector through the continuous radiological imaging, identifying a frame which includes an image signal representing an image of the contrast agent as a contrast agent frame from the radiation image signal of each frame, and correcting the radiation exposure dose based on information of the contrast agent frame and obtaining a radiation exposure dose of the subject for the radiological imaging of the contrast agent frame.

In a detection panel, plural pixels which receive X-ray and accumulate electric charge and plural measuring pixels which detect X-ray dose are provided on an imaging surface. The plural measuring pixels are arranged periodically with an interval. In a position facing to the imaging surface, there is a grid where X-ray absorbing sections and X-ray transmitting sections are arranged in a periodic alternating manner in a first direction. Since the arrangement period of the measuring pixels in the first direction is different from a fluctuation period of grid detection signals obtained when the grid is photographed by the detection panel, output values of the plurality of measuring pixels disperse and a fluctuation range of average values is suppressed.

The invention relates to a 3D display method of a radiation field. The method includes the following steps that: radiation source item data collected from a real radiation scene and a pre-constructedthree-dimensional scene model are coupled, so that a three-dimensional radiation field model can be obtained; a radiation source identifier specified by a user, in the three-dimensional scene model, is obtained, and a device identifier corresponding to the radiation source identifier is searched, the outer contour of the device identifier is a target projection surface; distance information inputted by the user is acquired, a to-be-displayed surface wrapping the target projection surface is determined according to the distance information; the sub-point sets of the to-be-displayed surface areselected from all point sets included in the to-be-displayed surface, wherein the selected sub-point sets can be accommodated by the target projection surface; and the radiation dose rate of all points in the sub-point sets is calculated according to the three-dimensional radiation field model, and the calculated radiation dose rate of all the points in the sub-point sets is projected onto the target projection surface so as to be displayed visually. The method of the invention can display of the radiation level of the radiation field in a 3D realistic manner.

The present invention provides a method for measuring a two-dimensional distribution of ionizing radiation doses with high spatial resolution. The method comprises exposing radiation sensitive film to a pattern of ionizing radiation to form a measurement film, exposing areas of radiation sensitive film to a plurality of known doses of the ionizing radiation to form a calibration film(s), scanning all the exposed films together with an unexposed radiation sensitive film at a single time to produce a digital image, measuring those areas of the digital image corresponding to the unexposed film and the calibration film(s) exposed to different known doses, associating the measured responses in the areas to the known doses and using the association to convert the values in the scanned image corresponding to the measurement film from scanner response values to dose values. In a preferred embodiment, all of the radiation sensitive films are the same type of film.

The invention relates to the radioactive source positioning field, and especially relates to a radioactive source positioning method and system. Multiple radioactive source detectors in different relative positions are adopted to carry out more than two times of detection on radioactive sources, and comparison is conducted on the basis of different detection results, so false positions during detection of the radioactive sources are removed. The radioactive source positioning method and system are simple in realization way, low in calculation complexity, and high in calculation precision.

The invention belongs to the technical field of radiation field uniformity measurement, and particularly relates to a ray radiation field dose rate measuring device and measuring method. The measuringdevice comprises an image sensor, an irradiation panel, a test evaluation board and a computer; the image sensor is arranged on an irradiation plate and is used for continuously acquiring images in the ray radiation field; the irradiation plate is connected with a test evaluation plate, and the test evaluation plate is connected with the computer, the computer is provided with an image processingsystem. According to the invention, the measurement data can be automatically processed, the measurement speed is greatly improved, and the damage time of the ray to the CMOS image sensor of the measuring device is reduced, the service life of the measuring device is prolonged, and the technical problems that the measuring device in the prior art is high in measuring cost and poor in precision are solved.

Provided are a method for measuring dose distribution in a mixed radiation field of neutrons and gamma rays, and a method for measuring beam uniformity of a mixed radiation field of neutrons and gamma rays. The planar dose measuring method includes: a step of obtaining a total dose of neutrons and gamma rays by measuring with a dosimeter; and a step of analyzing a neutron dose. The method may effectively measure the doses of neutrons and gamma rays, may be applied to beam measurement and treatment plan validation, and thus improve the quality of treatment.

The invention relates to a three-dimensional dose measurement and detection system of a particle therapy device. The three-dimensional dose measurement and detection system comprises a detector main body, a front-end electronics system, a data acquisition device and an upper computer, wherein the detector main body is used for detecting a particle beam; the front-end electronics system is used foramplifying an ionization signal generated by the detector body; the data acquisition device is used for acquiring signals amplified by the front-end electronics system; a particle photographing system and a three-dimensional dose reconstruction system are arranged in the upper computer; the particle photographing system is used for obtaining an imaging result of a target through a pre-trained machine network model by adopting data synchronously sampled before and after the target; and the three-dimensional dose reconstruction system performs three-dimensional dose reconstruction based on a pre-measured beam parameter dose curve model according to the imaging result of the target and the dose distribution information of the beam passing through the targets with different thicknesses to obtain the three-dimensional dose distribution of the beam passing through the target.

The invention provides a radioactive particle radiation dose measurement device.The measurement device comprises a tissue equivalent plate and particle through holes and dosimeter through holes which both penetrate through the tissue equivalent plate longitudinally.According to the radioactive particle radiation dose measurement device, the holes for containing radioactive particle and dosimeters are formed in the tissue equivalent plate and can fix the positions of the radioactive particles and the dosimeters, and therefore radiation dose measurement of the radioactive particles is conveniently conducted; radiation dose measurement is conducted by using the measurement device made of a tissue equivalent material, and therefore radiation values of the radioactive particles in a human body can be most truly and proximately reflected; the measurement devices of the different specifications can be arranged according to the distance among the particle through holes, the distance among the dosimeter through holes and the distance between the particle through holes and the dosimeter through holes, and then the radiation dose of single radioactive particle or more radioactive particles is measured.

A radiation imaging system includes a casing and a camera disposed inside the casing. A first field of view through the casing exposes the camera to light from outside of the casing. An image plate is disposed inside the casing, and a second field of view through the casing to the image plate exposes the image plate to high-energy particles produced by a radioisotope outside of the casing. An optical reflector that is substantially transparent to the high-energy particles produced by the radioisotope is disposed with respect to the camera and the image plate to reflect light to the camera and to allow the high-energy particles produced by the radioisotope to pass through the optical reflector to the image plate.