WO2001092913A2 - Scintillator detectro and camera system andmethod for measuring emission uniformity and for calibration of radioactive sources - Google Patents
Scintillator detectro and camera system andmethod for measuring emission uniformity and for calibration of radioactive sources Download PDFInfo
- Publication number
- WO2001092913A2 WO2001092913A2 PCT/US2001/016873 US0116873W WO0192913A2 WO 2001092913 A2 WO2001092913 A2 WO 2001092913A2 US 0116873 W US0116873 W US 0116873W WO 0192913 A2 WO0192913 A2 WO 0192913A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- scintillator
- light
- camera
- central hole
- radioactive sources
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
- G01T1/16—Measuring radiation intensity
- G01T1/161—Applications in the field of nuclear medicine, e.g. in vivo counting
- G01T1/164—Scintigraphy
- G01T1/1641—Static instruments for imaging the distribution of radioactivity in one or two dimensions using one or several scintillating elements; Radio-isotope cameras
- G01T1/1642—Static instruments for imaging the distribution of radioactivity in one or two dimensions using one or several scintillating elements; Radio-isotope cameras using a scintillation crystal and position sensing photodetector arrays, e.g. ANGER cameras
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T7/00—Details of radiation-measuring instruments
Definitions
- Radioactive sources emitting x-rays, gamma rays, beta particles or other radiation, are used in many applications, including industrial radiography and gauging, medical therapy and heat and power sources. In many of these applications the uniformity of radiation emission from the source is important. This is particularly true for low activity sources used for brachytherapy. In this case the radioactive source is placed on or inserted into the body to irradiate a tumor or lesion. Uniformity of emission is important, as is a calibration of the radiation emitted so that the radiation dose delivered to the patient can be accurately determined.
- Present methods for calibration of brachytherapy sources involve a variety of methods, including surrounding the source with multiple detectors, the use of multiple radiation probes or area detectors, such as film, and the use of well ionization chambers to measure the total radiation emitted from the source. These methods are cumbersome and, in many cases do not provide a complete determination of the emitted radiation patterns.
- U.S. Patent No. 5,661,310 which is incorporated by reference, discloses a radiation dose mapping system and method.
- a dosimeter made of a suitable luminescent material is provided between an image sensor such as a camera that is hooked up to a computer-based controller and a stimulator including an infrared light source.
- An optical stimulator source filter for producing only a narrow-band infrared spectrum and an optical image filter for preventing light produced by the stimulator from being conveyed to the camera are provided between the stimulator and the dosimeter.
- the device permits mapping of spatially variable radiation patterns for use in medical radiation treatments and does so without the requirement of chemical processing.
- the device is not adapted to permit analysis of circumferential variations in a sample, i.e., radial variations, or axial variations in a sample.
- the method and system according to the present invention makes use of a thick, cylindrical scintillator observed through a mirror by a camera. If the source to be calibrated is placed in a central hole in the thick scintillator, the emitted light will show variations in both the circumferential, i.e., radial, and axial emission patterns from the source. A conical mirror around the scintillator will direct the emitted light toward the camera.
- Variations in the circumferential, i.e., radial, radiation emission from the source will be detected as variations in the circumferential pattern of the emitted light from the scintillator. Variations in the axial radiation from the source will be observed in the same image presentation as variations along the radial direction of the round image.
- a conical reflector at least partially surrounds the cylindrical scintillator and is arranged to reflect light that exits the sides of the scintillator and direct the light in a first direction.
- a camera is arranged to detect the light reflected from the conical reflector and produce image data corresponding to the detected light.
- a cylindrical scintillator has a central hole for receiving one or more radioactive sources.
- the scintillator is adapted to permit light stimulated in the scintillator by the one or more radioactive sources in the central hole to exit out of the sides of the scintillator.
- a method for determining uniformity of radiation emission from one or more radioactive sources includes inserting a radioactive source in a central hole of a scintillator, the scintillator being adapted to permit light stimulated in the scintillator by the radioactive source in the central hole to exit out of the sides of the scintillator.
- Light that exits the sides of the scintillator is reflected with a reflector and the light is directed in a first direction. After the light has been directed in the first direction, the light is detected with a camera.
- FIG. 1A schematically shows a system configuration for brachytherapy seed profiling with a thick scintillator and a conical mirror according to an embodiment of the present invention
- FIG. IB is a top view of a portion of the system of FIG. 1A;
- FIG. 2 shows an image pattern in a conical mirror for the system shown in FIG. 1A;
- FIG. 3A schematically shows a brachytherapy seed calibration system according to an embodiment of the present invention with stepped phosphor detector
- FIG. 3B is a top view of a portion of the system of FIG. 3 A.
- FIG. 4 schematically shows an embodiment of a thick scintillator wherein fibers run radially.
- FIG. 1A shows a thick, central hole scintillator 22.
- the scintillator 22 may be in the form of a solid glass (such as Type IQI 301 or 401, available from Industrial Quality, Inc., Gaithersburg, MD 20877), an inorganic scintillator such as cesium iodide or sodium iodide (available from Radiation Monitoring Devices, Watertown, MA) or other scintillation material.
- a solid glass such as Type IQI 301 or 401, available from Industrial Quality, Inc., Gaithersburg, MD 20877
- an inorganic scintillator such as cesium iodide or sodium iodide (available from Radiation Monitoring Devices, Watertown, MA) or other scintillation material.
- the scintillator 22 may also be in the form of scintillating glass, columnar inorganic scintillator or scintillating plastic fibers in which fibers or columns, 22c run in a radial direction, as shown in FIG. 4.
- the outer perimeter of the cylindrical scintillator 22 is polished to permit light to exit from the sides as radiation stimulates light emission within the scintillator.
- a conical reflector 27 around the scintillator reflects the emitted light toward a camera 21.
- a top shield, 25a shields the source from the scintillator until the source enters the hole in the scintillator.
- a bottom shield, 25b is preferably conical as illustrated to minimize obstructions in the light path but, if desired or necessary, may be cylindrical.
- FIGS. IB and 3B show a portion of the system of FIGS. 1A and 3 A from the top.
- the emitted light displays variations in the source radiation emitted in both the circumferential, i.e., radial, and longitudinal directions, as shown in the image 29 seen in FIG. 2.
- FIGS. 1A and 3A yields a camera image that can readily relate to the radiation dose delivered to tissue at distances that correlate with the tissue-equivalent plastic separator 31 between the source S and a phosphor layer 33.
- the image in the embodiments of FIGS. 1A and 3 A may be viewed by the camera directly through the conical mirror, or through a turning mirror 23a.
- the camera 21 can, of course, be associated with a computer for analysis and storage of information about the source and the reference to a camera is meant to encompass any suitable device capable of obtaining and recording or transmitting an image.
- the scintillator 22 (glass, inorganic or plastic) is a thick circular cylinder with the outside perimeter surface polished.
- the outer cylinder wall of the scintillator 22 is viewed through a conical mirror, shown as item 27.
- This approach permits superior shielding of the active portions of the seeds or strings of seeds that are either above or below the active scintillator 22, as provided by shields 25a and 25b in FIGS. 1A and 3A.
- the circumferential, i.e., radial, symmetry of the source activity is imaged as brightness variations around the perimeter of the scintillator 22.
- a string of radioactive seeds may be totally contained within the long scintillating cylinder, thereby avoiding problems caused by radioactive material above or below the scintillator.
- Variations in the axial activity display as variations in brightness in the radial direction of the resulting image 29. This is illustrated in FIG. 2.
- a variant of this approach would use a solid, tissue-equivalent plastic absorbing cylinder with a fluorescent phosphor, such as gadolinium-oxysulfide, on the outer surface. This approach offers the advantage of displaying a signal that relates to the dose deposited in tissue at a fixed distance away from the seeds.
- FIG. 3A top view shown in FIG. 3B
- FIG. 3A top view shown in FIG. 3B
- FIG. 3A top view shown in FIG. 3B
- the shields, 25a and 25b are preferably made of a material having an atomic number that is appropriately high for the isotope being imaged, such as lead or tungsten alloy for gamma or x-ray emitting sources.
- Leaded glass or plastic shields can be effectively used as the bottom shield, 25b, in order to allow a clear visible path for the emitted light to reach the camera.
- the shield material should not be made of high atomic number materials, so as to avoid the production of x-rays in the shield material. Clear plastic shields, such as polyethylene, are preferred.
- the final result obtained from this invention is a representation of the radiation emission pattern from a radioactive source or a string of such sources.
- these radiation data can be related to radiation dose delivered to a patient, thereby making the radiation therapy more efficient and safer to use.
- the scintillator-camera system described here offers a rapid, complete characterization of the radiation pattern emitted by a radioactive source.
- the system is operated through a user interface developed using virtual instrumentation and serves as the operator control panel. Image acquisition and image conversion is automatically handled by the custom designed software. Due to the nature of the conical mirror assembly, the brightness or light intensity varies along the radial direction of the mirror surface. This is due to the variation of distance between the surface of the mirror and the surface of the scintillator along its axis, so the light intensity variation is intrinsic to the design of the mirror assembly.
- a portion of the control system software is a correction algorithm that accepts the image of the mirror assembly and converts the variable, circular image to a linear, planar image for display to the operator. The algorithm uses a geometric normalization to remove the variation of the conical mirror light intensity so that the true scintillator light intensity is displayed and readily evaluated by the analysis software routines.
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2001271271A AU2001271271A1 (en) | 2000-05-26 | 2001-05-25 | Scintillator detector and camera system and method for measuring emission uniformity and for calibration of radioactive sources |
US10/297,524 US20040051045A1 (en) | 2001-05-25 | 2001-05-25 | Scintillator detector and camera system and method for measuring emission uniformly and for calibration of radioactive sources |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US20722200P | 2000-05-26 | 2000-05-26 | |
US60/207,222 | 2000-05-26 |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2001092913A2 true WO2001092913A2 (en) | 2001-12-06 |
WO2001092913A3 WO2001092913A3 (en) | 2002-03-28 |
Family
ID=22769671
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2001/016873 WO2001092913A2 (en) | 2000-05-26 | 2001-05-25 | Scintillator detectro and camera system andmethod for measuring emission uniformity and for calibration of radioactive sources |
PCT/US2001/016874 WO2001092831A1 (en) | 2000-05-26 | 2001-05-25 | Scintillator detector and camera system and method for measuring emission uniformity and for calibration of radioactive sources |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2001/016874 WO2001092831A1 (en) | 2000-05-26 | 2001-05-25 | Scintillator detector and camera system and method for measuring emission uniformity and for calibration of radioactive sources |
Country Status (2)
Country | Link |
---|---|
AU (2) | AU2001275837A1 (en) |
WO (2) | WO2001092913A2 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102009033304A1 (en) | 2009-07-15 | 2011-01-27 | Siemens Aktiengesellschaft | Detector for use in X-ray computed tomography device for generating X-ray radiation on patient during scanning patient for diagnosis purpose, has digital camera arranged in region estimatable by X-ray radiation |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3859528A (en) * | 1973-03-26 | 1975-01-07 | Beckman Instruments Inc | Gamma ray apparatus with sample changer |
US3978337A (en) * | 1975-01-29 | 1976-08-31 | Wisconsin Alumni Research Foundation | Three-dimensional time-of-flight gamma camera system |
US4495419A (en) * | 1982-06-11 | 1985-01-22 | Schmehl Stewart J | Radiation detection device |
US5032728A (en) * | 1988-11-09 | 1991-07-16 | The University Of Iowa Research Foundation | Single photon emission computed tomography system |
US5471062A (en) * | 1994-03-21 | 1995-11-28 | The Regents Of The University Of California | Large volume flow-through scintillating detector |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3878373A (en) * | 1971-06-30 | 1975-04-15 | Alvin Blum | Radiation detection device and a radiation detection method |
US3739171A (en) * | 1971-07-19 | 1973-06-12 | Texaco Inc | Gamma ray spectroscopy with quantitative analysis |
US4066908A (en) * | 1976-03-31 | 1978-01-03 | The Harshaw Chemical Company | Well-type scintillation assembly |
US4946238A (en) * | 1984-01-27 | 1990-08-07 | University Of Pittsburgh | Fiber optic coupler |
US5235191A (en) * | 1992-03-06 | 1993-08-10 | Miller Robert N | Real-time x-ray device |
US5594253A (en) * | 1994-12-28 | 1997-01-14 | Lockheed Missiles And Space Company, Inc. | Hybrid luminescent device for imaging of ionizing and penetrating radiation |
US5606638A (en) * | 1995-12-26 | 1997-02-25 | Nanoptics Incorporated | Organic scintillator systems and optical fibers containing polycyclic aromatic compounds |
-
2001
- 2001-05-25 WO PCT/US2001/016873 patent/WO2001092913A2/en active Application Filing
- 2001-05-25 AU AU2001275837A patent/AU2001275837A1/en not_active Abandoned
- 2001-05-25 WO PCT/US2001/016874 patent/WO2001092831A1/en active Application Filing
- 2001-05-25 AU AU2001271271A patent/AU2001271271A1/en not_active Abandoned
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3859528A (en) * | 1973-03-26 | 1975-01-07 | Beckman Instruments Inc | Gamma ray apparatus with sample changer |
US3978337A (en) * | 1975-01-29 | 1976-08-31 | Wisconsin Alumni Research Foundation | Three-dimensional time-of-flight gamma camera system |
US4495419A (en) * | 1982-06-11 | 1985-01-22 | Schmehl Stewart J | Radiation detection device |
US5032728A (en) * | 1988-11-09 | 1991-07-16 | The University Of Iowa Research Foundation | Single photon emission computed tomography system |
US5471062A (en) * | 1994-03-21 | 1995-11-28 | The Regents Of The University Of California | Large volume flow-through scintillating detector |
Also Published As
Publication number | Publication date |
---|---|
WO2001092831A1 (en) | 2001-12-06 |
WO2001092913A3 (en) | 2002-03-28 |
AU2001271271A1 (en) | 2001-12-11 |
AU2001275837A1 (en) | 2001-12-11 |
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