EP0337096A1 - Détecteur modulaire pour une caméra à scintillation - Google Patents

Détecteur modulaire pour une caméra à scintillation Download PDF

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Publication number
EP0337096A1
EP0337096A1 EP89103518A EP89103518A EP0337096A1 EP 0337096 A1 EP0337096 A1 EP 0337096A1 EP 89103518 A EP89103518 A EP 89103518A EP 89103518 A EP89103518 A EP 89103518A EP 0337096 A1 EP0337096 A1 EP 0337096A1
Authority
EP
European Patent Office
Prior art keywords
scintillator
strips
scintillation
detector module
scintillator strips
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
EP89103518A
Other languages
German (de)
English (en)
Inventor
Dennis E. Persyk
James J. Hamill
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens AG
Siemens Corp
Original Assignee
Siemens AG
Siemens Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens AG, Siemens Corp filed Critical Siemens AG
Publication of EP0337096A1 publication Critical patent/EP0337096A1/fr
Ceased legal-status Critical Current

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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
    • 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
    • G01T1/1644—Static instruments for imaging the distribution of radioactivity in one or two dimensions using one or several scintillating elements; Radio-isotope cameras using an array of optically separate scintillation elements permitting direct location of scintillations
    • 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
    • G01T1/20—Measuring radiation intensity with scintillation detectors
    • G01T1/2008—Measuring radiation intensity with scintillation detectors using a combination of different types of scintillation detectors, e.g. phoswich
    • 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
    • G01T1/20—Measuring radiation intensity with scintillation detectors
    • G01T1/2018—Scintillation-photodiode combinations
    • G01T1/20182—Modular detectors, e.g. tiled scintillators or tiled photodiodes
    • 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
    • G01T1/20—Measuring radiation intensity with scintillation detectors
    • G01T1/2018—Scintillation-photodiode combinations
    • G01T1/20187—Position of the scintillator with respect to the photodiode, e.g. photodiode surrounding the crystal, the crystal surrounding the photodiode, shape or size of the scintillator
    • 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
    • G01T1/20—Measuring radiation intensity with scintillation detectors
    • G01T1/202—Measuring radiation intensity with scintillation detectors the detector being a crystal

Definitions

  • the invention relates to scintillation cameras, and more particularly relates to detectors which are used in such cameras. In its most immediate sense, the invention relates to detectors in which a temperature gradient is established across the scintillator.
  • the X-Y location of a scintillation event is determined by evaluating the outputs of a plurality of photomultiplier tubes which view the event. These photomultiplier tubes are connected to a resistor matrix and the X and Y coordinates of the detected event are computed by appropriately weighting the outputs of the photomultiplier tubes involved.
  • a scintillation camera conventionally utilizes a large scintillation crystal which must be relatively uniform throughout its entire volume. As a result, such crystals are relatively expensive.
  • a detector module produces X-Y information by utilizing a plurality of parallel scintillator strips.
  • a temperature gradient is established along one axis of the detector module and the scintillator strips extend along another perpendicular axis.
  • Means are provided for identifying the particular scintillator strip in which a scintillation event occurs and for monitoring the decay time of the scintillation event. Because the decay time is a function of the temperature of the site at which a scintillation event takes place, and because this temperature is associated with a particular location along the scintillator strip, the decay time provides information about e.g. the X coordinate of a detected scintillation event.
  • both the X and Y coordinates of a detected scintillation event can be determined.
  • the decay time of the scintillation event is determined by evaluating the output of a photomultiplier tube. While the use of a photomultiplier tube is common in scintillation camera detectors, the use of the tube in this application is unique because the tube is not used to measure anything except the energy of the scintillation event and the decay time of the event. There is no weighting of the signals from a plurality of photomultiplier tubes.
  • the scintillator strips are made of different scintillator materials, which have distinguishable decay time versus temperature responses.
  • the scintillator strips are linked together in groups (e.g. in pairs if two different scintillator materials are used; in triplets if three different scintillator materials are used, and so on) and each group is optically linked to a common photodiode.
  • the output of the photodiode localizes the scintillation event to the group level along the Y axis, and the decay time as measured by the photomultiplier tube localizes the event to a particular scintillator strip (i.e. a particular Y coordinate) and to a particular X coordinate.
  • Fig. 1 shows a plurality (here, six but the number is not part of the invention) of elongated scintillator strips 2, 4, 6, 8, 10 and 12 which are arranged to form a rectangular region.
  • the strips are 1/4 inch wide by 1/2 inch thick by 3 inches long, but these dimensions are not part of the invention.
  • the width of the strip determines the resolution of the detector module and the 1/4 inch figure was chosen because such a resolution is believed satisfactory for nuclear medicine application.
  • the thickness of the strip determines the stopping power of the scintillators and 1/2 inch was chosen because this thickness will stop 90 - 95% of all incident 140 keV gamma radiation.
  • Each scintillator strip has a first end (e.g. 2A, 4A, etc.) and a second end, (2B, 4B, etc.) and all the first ends (2A, 4A, etc.) of the strips are aligned to form a first side 16 of the region and all the second ends of the strips (2B, 4B, etc.) are aligned to form a second side 18 of the region.
  • the region is normal to the direction of incidence of incoming gamma radiation.
  • scintillator strips 2, 6 and 10 are made of NaI(Tl) and the other half (namely scintillator strips 4, 8 and 12) are made of CsI(Na). As shown, the scintillator strips are alternated so that adjacent scintillator strips are always made of different materials.
  • the scintillator strips 2, 4 ... 12 form three pairs 20, 22 and 24, each pair 20, 22 and 24 containing a CsI(Na) strip and a NaI(Tl) strip.
  • the pair 20 contains a NaI(Tl) scintillator strip 2 and a CsI(Na) scin­tillator strip 4.
  • the first end of each of the strips in each pair are optically coupled together through a small light pipe, (e.g. 26) which is also coupled to an avalanche photodiode (e.g. 32 Fig. 2).
  • the six strips are all optically coupled (as by a large light pipe, not shown) to a photomultiplier tube 38.
  • the output 40 of the photomultiplier tube 38 is connected to a circuit 42 which is used to determine the decay time of scintillation events registered by the photo­multiplier tube 38.
  • the details of such circuits are known to persons skilled in the art and are therefore not described here. Some such details are contained in the EP-A-0 262 524.
  • a temperature gradient is established along the lengths of the scintillator strips 2, 4 ... 12.
  • the first side 16 is held at a temperature of approximately 0°C or below, and the second side 18 is held at a higher temperature.
  • the temperature gradient is chosen to provide the resolution desired; the greater the gradient, the greater the resolution. 0°C was chosen because this reduces thermal noise output from the photodiodes described below.
  • the decay time of a scintillation event detected by the photomultiplier tube 38 represents the location of the event along the X axis where, as here, a temperature gradient is established in the X direction.
  • the Y position of the event is represented (to an accuracy equalling the width of a scintillator strip) by the particular strip (e.g. 2, or 4 etc.) in which the scintillation event has taken place. It would be possible to identify the strip (and therefore the Y coordinate) by mounting an avalanche photodiode to each individual one of the scintillator strips and registering, for each scintillation event, the identity of the correspondingly fired photodiode. However, this would be costly because avalanche photodiodes are highly expensive. Accordingly, in the preferred embodiment, the number of these photodiodes (e.g. 26, 28 and 30) is reduced.
  • the decay time characteristics of e.g. Nal(Tl) are distinguishable from the decay time characteristics of CsI(Na).
  • One measure of decay time is the time required for a scintillation event to decay from 90% of its maximum amplitude to 10% of its maximum amplitude, and this is shown in Fig. 3 in an illustrative (not to scale) manner.
  • the signal from the photomultiplier tube 38 is used to determine a) the identity of the scintillator material in which the scintillation event has taken place and b) the X coordinate of the scintillation event.
  • a scintillation event E at the location shown in Fig.
  • fall time as a measure of decay time is preferred because, in the temperature ranges which are currently under investigation, the fall time provides a basis upon which to distinguish between NaI(Tl) scintillations and CsI(Na) scintillations.
  • the shapes of the decay time vs. temperature curves also differ between NaI(Tl) scintillations and CsI(Na) scintillations and these shape differences may also be used to accomplish the distinction.
  • Persons skilled in the art can adapt the circuit 42 to measure whatever scintillation characteristics are used as the distinguishing features.
  • scintillation materials are not necessary to the invention. If photodiodes drop in price, one material may be used and a photodiode may be mounted to each strip. Alternatively, more scintillator materials may be used, to increase the number of strips in each group and thereby further reduce the number of photodiodes.
  • PIN photodiodes instead of avalanche photodiodes.
  • the scintillator strips are long, there may be two photodiodes for each, one at each of the ends.
  • the temperature along the first side 16 of the region is kept at 0°C or below to reduce the effect of thermal noise on the outputs from the photodiodes 26, 28 and 30.
  • a heat sink made of a material with comparatively high thermal conductivity may advantageously be fixed along the first side 16 of the region and cooled to an appropriate temperature, while another heat sink which is appropriately heated/cooled may be fixed along the second side 18.
  • the method by which the thermal gradient is established is not part of the invention.
  • the module disclosed alone can be replicated in whatever configuration is required, since the problem of "edge packing" is minimized.
  • a plurality of such modules can be disposed so that all the scintillator strips occupy a common plane, or so that the surfaces of the modules form a desired configuration, e.g., a surface which is a closed curve viewed on end and which surrounds a patient.

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  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Molecular Biology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Biomedical Technology (AREA)
  • General Health & Medical Sciences (AREA)
  • Medical Informatics (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Optics & Photonics (AREA)
  • Measurement Of Radiation (AREA)
  • Nuclear Medicine (AREA)
EP89103518A 1988-03-29 1989-02-28 Détecteur modulaire pour une caméra à scintillation Ceased EP0337096A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US174574 1988-03-29
US07/174,574 US4879465A (en) 1986-09-30 1988-03-29 Detector module for scintillation cameras

Publications (1)

Publication Number Publication Date
EP0337096A1 true EP0337096A1 (fr) 1989-10-18

Family

ID=22636666

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89103518A Ceased EP0337096A1 (fr) 1988-03-29 1989-02-28 Détecteur modulaire pour une caméra à scintillation

Country Status (3)

Country Link
US (1) US4879465A (fr)
EP (1) EP0337096A1 (fr)
JP (1) JPH01285887A (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009058542A1 (fr) * 2007-10-30 2009-05-07 Rigaku Innovative Technologies, Inc. Détecteur à scintillation avec fenêtre d'entrée pouvant être chauffée

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04213091A (ja) * 1990-12-10 1992-08-04 Konica Corp 放射線量検出装置
US5338937A (en) * 1993-06-14 1994-08-16 Sloan-Kettering Institute For Cancer Research Radiation imaging device having an enlarged uniform field of view
US5753917A (en) * 1995-06-06 1998-05-19 Engdahl; John C. Dual crystal scintillation camera
US6749761B1 (en) * 2000-10-10 2004-06-15 Cti Pet Systems, Inc. Method for producing a high resolution detector array
US7157014B1 (en) 2001-10-05 2007-01-02 Cit Pet Systems, Inc. Method for producing a high resolution detector array
WO2004111681A1 (fr) * 2003-06-19 2004-12-23 Ideas Asa Detecteur de rayonnement modulaire dote de scintillateurs, de photodiodes a semiconducteur et d'un circuit de lecture integre, et leur procede d'assemblage
WO2019103997A1 (fr) * 2017-11-24 2019-05-31 Saint-Gobain Ceramics & Plastics, Inc. Substrat comprenant des matériaux scintillateurs, système comprenant ledit substrat et procédé d'utilisation

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2543691A1 (fr) * 1983-03-31 1984-10-05 Sendyk Andrzej Detecteur pour la detection de position d'une radiation ionisante
EP0219648A1 (fr) * 1985-10-18 1987-04-29 Clayton Foundation for Research Caméra pour tomographie à positrons avec plusieurs ensembles coplanaires de détecteurs
EP0262524A1 (fr) * 1986-09-30 1988-04-06 Siemens Aktiengesellschaft Scintillateur chauffé

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4037105A (en) * 1976-06-01 1977-07-19 Laurer Gerard R Radiation detector with array of different scintillators
US4672207A (en) * 1985-08-21 1987-06-09 The United States Of America As Represented By The United States Department Of Energy Readout system for multi-crystal gamma cameras

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2543691A1 (fr) * 1983-03-31 1984-10-05 Sendyk Andrzej Detecteur pour la detection de position d'une radiation ionisante
EP0219648A1 (fr) * 1985-10-18 1987-04-29 Clayton Foundation for Research Caméra pour tomographie à positrons avec plusieurs ensembles coplanaires de détecteurs
EP0262524A1 (fr) * 1986-09-30 1988-04-06 Siemens Aktiengesellschaft Scintillateur chauffé

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009058542A1 (fr) * 2007-10-30 2009-05-07 Rigaku Innovative Technologies, Inc. Détecteur à scintillation avec fenêtre d'entrée pouvant être chauffée
US7684545B2 (en) 2007-10-30 2010-03-23 Rigaku Innovative Technologies, Inc. X-ray window and resistive heater

Also Published As

Publication number Publication date
US4879465A (en) 1989-11-07
JPH01285887A (ja) 1989-11-16

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