Radiation dosimetry method and apparatus
First Claim
1. A radiation dosimeter, comprising:
- a substrate;
a layer of radiation sensitive material on said substrate, said radiation sensitive material having an optical density which varies in accordance with a degree of radiation exposure of said radiation sensitive material;
optically readable first coding disposed on said substrate, said coding identifying encoded mathematical parameters for enabling an automated calculation of radiation dosage from a detected change in optical density of said radiation sensitive material; and
additional optically readable second coding on said substrate for uniquely identifying the dosimeter.
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Abstract
A method for determining a level of exposure to radiation utilizes a radiation dosimeter comprising a substrate provided with a radiation sensitive layer or patch having an optical density which varies in accordance with the degree of radiation exposure. In addition, the substrate is provided with optically readable coding which identifies encoded mathematical parameters for enabling an automated calculation of dosage from a detected post-exposure optical density of the radiation sensitive material. The method comprises the step of optically measuring the optical density of the layer of radiation sensitive material prior to exposure thereof to radiation. In addition, the coding on the dosimeter substrate is scanned to automatically determine the encoded mathematical parameters. The method further comprises the steps of exposing the radiation sensitive layer to radiation and optically measuring a post-exposure optical density of the layer of radiation sensitive material. Subsequently, from the pre-exposure optical density, the post-exposure optical density, and the mathematical parameters and in accordance with a predetermined mathematical algorithm, a quantitative radiation dose to which the layer of radiation sensitive material was exposed is automatically computed. Preferably, the computed quantitative radiation dose is automatically indicated on a display. Each dosimeter may be provided with a unique identification code encoded in the bar coding on the dosimeter substrate, to enable memory storage of pre-exposure optical densities for multiple dosimeters. A look-up table may be stored in memory for enabling correction of computed optical densities where the post-exposure densities are measured at different times intervals after exposure.
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Citations
25 Claims
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1. A radiation dosimeter, comprising:
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a substrate; a layer of radiation sensitive material on said substrate, said radiation sensitive material having an optical density which varies in accordance with a degree of radiation exposure of said radiation sensitive material; optically readable first coding disposed on said substrate, said coding identifying encoded mathematical parameters for enabling an automated calculation of radiation dosage from a detected change in optical density of said radiation sensitive material; and additional optically readable second coding on said substrate for uniquely identifying the dosimeter. - View Dependent Claims (2, 3, 4)
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5. A dose reader instrument comprising:
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optical sensing means for sensing a range of variable optical densities on a substrate; measuring means operatively connected to said optical sensing means for determining an optical density of a layer of radiation sensitive material on said substrate; decoding means operatively connected to said optical sensing means for decoding mathematical parameters encoded in an optically readable coding on said substrate; computing means operatively connected to said measuring means and said decoding means for computing, according to a predetermined mathematical function including a measured post-exposure value of said optical density and parameters determined from said coding by said decoding means, a quantitative radiation dose to which said layer of radiation sensitive material was exposed; communicating means operatively connected to said computing means for communicating the computed quantitative radiation dose to an operator; and timing means operatively coupled to said computing means for enabling said computing means to compute said quantitative radiation dose only upon the lapse of a preset interval after exposure of said layer of radiation sensitive material to radiation. - View Dependent Claims (6, 7, 8, 9, 10, 11)
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12. A method for determining a level of exposure to radiation, comprising:
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providing a radiation dosimeter including a layer of radiation sensitive material on a substrate, said radiation sensitive material having an optical density which varies in accordance with a degree of radiation exposure, the radiation dosimeter also including an optically readable first coding disposed on said substrate, said first coding identifying encoded mathematical parameters, the radiation dosimeter being additionally provided with optically readable second coding uniquely identifying the dosimeter; prior to exposure of said radiation sensitive material to radiation, optically measuring a first optical density of said layer of radiation sensitive material; automatically reading said second coding to determine the identity of the dosimeter; and automatically storing said first optical density in electronically encoded form in a memory location associated with the determined identity of the dosimeter; optically scanning said first coding to automatically determine said mathematical parameters; after measuring said first optical density, exposing said layer of radiation sensitive material to radiation; after exposure of said layer of sensitive material to radiation, optically measuring a second optical density of said layer of radiation sensitive material; and automatically computing, from said first optical density, said second optical density, and said mathematical parameters and in accordance with a predetermined mathematical algorithm, a quantitative radiation dose to which said layer of radiation sensitive material was exposed. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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20. A method for determining a level of exposure to radiation, comprising:
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providing a radiation dosimeter including a layer of radiation sensitive material on a substrate, said radiation sensitive material having an optical density which varies in accordance with a degree of radiation exposure of the radiation sensitive material; scanning said substrate to determine calibration information relating to said layer of radiation sensitive material; exposing said layer of radiation sensitive material to radiation; after exposure of said layer to radiation, optically measuring a post-exposure optical density of said layer of radiation sensitive material; automatically computing from said calibration information and said optical density and in accordance with a predetermined mathematical algorithm, a quantitative radiation dose to which said layer of radiation sensitive material was exposed; measuring a time interval between exposing said layer of radiation sensitive material to radiation and measuring the post-exposure optical density of said radiation sensitive layer; and automatically modifying the computed quantitative radiation dose in accordance with a difference between the measured time interval and a preset interval. - View Dependent Claims (21, 22, 23)
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24. A dose reader instrument comprising:
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optical sensing means for sensing a range of variable optical densities on a substrate; measuring means operatively connected to said optical sensing means for determining an optical density of a layer of radiation sensitive material on said substrate; decoding means operatively connected to said optical sensing means for decoding mathematical parameters encoded in an optically readable coding on said substrate; computing means operatively connected to said measuring means and said decoding means for computing, according to a predetermined mathematical function including a measured post-exposure value of said optical density and parameters determined from said coding by said decoding means, a quantitative radiation dose to which said layer of radiation sensitive material was exposed; communicating means operatively connected to said computing means for communicating the computed quantitative radiation dose to an operator; timing means operatively coupled to said computing means for measuring a time interval between exposure of said layer of radiation sensitive material to radiation and an operation of said measuring means to determine said post-exposure value of said optical density; and means operatively connected to said computing means for enabling a modification of the computed radiation dose in accordance with a difference between said interval and a preset interval. - View Dependent Claims (25)
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Specification