EP0864106A2 - Capteur de mesure d'une dose de rayonnement equivalente au tissu - Google Patents

Capteur de mesure d'une dose de rayonnement equivalente au tissu

Info

Publication number
EP0864106A2
EP0864106A2 EP96946337A EP96946337A EP0864106A2 EP 0864106 A2 EP0864106 A2 EP 0864106A2 EP 96946337 A EP96946337 A EP 96946337A EP 96946337 A EP96946337 A EP 96946337A EP 0864106 A2 EP0864106 A2 EP 0864106A2
Authority
EP
European Patent Office
Prior art keywords
radiation
sensitive optical
optical waveguide
sensor
light
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.)
Withdrawn
Application number
EP96946337A
Other languages
German (de)
English (en)
Inventor
Friedrich Wolfgang HÄSING
Frank Pfeiffer
Harald BÜKER
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.)
Forschungszentrum Juelich GmbH
Original Assignee
Forschungszentrum Juelich GmbH
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 Forschungszentrum Juelich GmbH filed Critical Forschungszentrum Juelich GmbH
Publication of EP0864106A2 publication Critical patent/EP0864106A2/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T5/00—Recording of movements or tracks of particles; Processing or analysis of such tracks
    • G01T5/08—Scintillation chambers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/02—Dosimeters
    • G01T1/06—Glass dosimeters using colour change; including plastic dosimeters

Definitions

  • the invention relates to a sensor having a radiation-sensitive optical waveguide for measuring a tissue-equivalent radiation dose.
  • Detection sensitivity could be achieved by using long radiation-sensitive optical fibers increase. However, this would involve a correspondingly lower spatial resolution.
  • the object of the invention is to provide a sensor for measuring a tissue-equivalent radiation dose which does not have the aforementioned disadvantages.
  • a glass fiber without heavy doping elements is suitable as a tissue-equivalent measuring, radiation-sensitive optical waveguide (sensor fiber).
  • Suitable doping elements are in particular lithium, magnesium and sodium.
  • Optical waveguide has mirroring on the end faces. In order to be able to couple light into and out of the optical waveguide, it is particularly provided that only partially mirror at least one end face. The light can enter or exit the radiation-sensitive optical waveguide through the non-reflecting part.
  • mirroring at one or both ends is designed to be totally reflective.
  • the radiation-sensitive optical waveguide has a totally reflecting end.
  • a totally reflecting end is present when the light passing through the radiation-sensitive optical waveguide strikes the totally reflecting end surface (surface of the totally reflecting end) at such an angle of incidence that total reflection occurs due to the law of refraction.
  • the radiation-sensitive optical waveguide is then the optically denser medium in comparison to the medium which adjoins the totally reflecting end face.
  • the totally reflecting end has in particular the shape of a tip.
  • the tip preferably forms a right angle. Then there is a cut through that
  • Tip that represents an isosceles triangle with a right angle.
  • the provision of totally reflecting mirroring avoids absorption losses which occur with conventional mirroring.
  • the light in the radiation-sensitive optical waveguide can then be reflected back and forth more often.
  • the light path in the radiation-sensitive optical waveguide is further extended compared to conventional mirroring. and so the sensitivity is increased again.
  • Light paths of up to 100 m are possible.
  • the number of materials that can be used for the radiation-sensitive optical waveguide is thus further increased.
  • the complex dielectric multilayers required for conventional mirroring are eliminated.
  • a totally reflecting end is therefore cheaper to manufacture.
  • a route-neutral measuring method can therefore be carried out with the sensor according to the claims.
  • the aforementioned ratio has a significant influence on the number of back and forth reflections in the radiation-sensitive optical waveguide.
  • FIG. 1 sensor for measuring a tissue-equivalent radiation dose
  • FIG. 2 simulation of irradiation of a sensor (MPC) according to the invention in comparison to a conventional sensor
  • FIGS. 3-5 experimental results
  • FIG. 6 radiation-sensitive optical waveguide with totally reflecting ends
  • FIG. 1 shows a radiation-sensitive optical waveguide 4 which has reflectors 2 at its ends.
  • One of the mirror coatings 2 has an opening 1.
  • a radiation-insensitive transmission fiber 3 is connected to the radiation-sensitive optical waveguide 4 through the opening 1. Light can be coupled into and out of the radiation-sensitive optical waveguide 4 via the transmission fiber 3.
  • a twin fiber can be used instead of a single transmission fiber 3.
  • the light is then coupled in and out via two separate fibers. Fresnel reflections at the interfaces then advantageously have no influence. However, the sensitivity is lower since the fiber that is coupled in also couples out light that is lost for the measurement.
  • An analog structure with one or two radiation-resistant transmission fibers can also be implemented for thin glass rods, which are prepared in the same way. Provided that a corresponding glass composition is present, an approximately tissue-equivalent display is possible.
  • FIG. 2 shows the simulation of an irradiation of a sensor (MPC) according to the invention compared to a conventional sensor with an approximately tissue-equivalent measuring optical waveguide.
  • Lengths of 5 mm were assumed for both sensor fibers, a dose rate of 1.1 Gy / min and a reflectivity of the mirror surfaces of 99%.
  • the ratio of the opening 1 to the cross section of the radiation-sensitive fiber 4 was 0.055.
  • the attenuation of the cavity depends on the basic fiber attenuation, the reflectivity of the mirror and the ratio of the opening 1 to the cross section of the radiation-sensitive fiber 4.
  • 3 to 5 show three graphs which show the result of the irradiation of two PbO transmission sensors at three different wavelengths.
  • Transmission sensors are based on the principle of multipath cavity (MPC). This means that the cavity is mirrored on both sides, but openings are also introduced into the vapor deposition on both sides in order to enable a coupling for a transmission measurement. This inevitably reduces the effectiveness of the cavity. However, the experimental setup is facilitated.
  • MPC multipath cavity
  • the fiber length of the conventional transmission sensor is 38.4 mm, that of the cavity 51.0 mm.
  • the measured attenuation is normalized to one meter of fiber length in order to enable a direct comparison.
  • the dose rate is 1.0 Gy / min.
  • For this special sensor there is an increase in fiber attenuation in the multipath cavity by 2 dB within three minutes of irradiation at a wavelength of 450 nm. With increasing radiation exposure to the fiber, the detection sensitivity of the MPC drops more compared to the conventional sensor, since there are small increases the basic attenuation already deteriorate the transmission of the cavity.
  • FIG. 6 shows a longitudinal section through a sensor, shown on a scale of 50: 1.
  • the sensor has a radiation-sensitive optical waveguide 4 with totally reflecting mirrored ends.
  • the radiation-sensitive optical waveguide 4 consists of a glass rod, the end faces 2 of which taper to a point. The tip forms a right angle.
  • light located in the glass rod, which radiates parallel to the longitudinal axis of the glass rod, is totally reflected due to the law of refraction.
  • the tip created by prism grinding is ground off at one end of the glass rod 4 perpendicular to the axis of the glass rod 4.
  • This grinding creates a surface 1.
  • a single-mode fiber 3 is coupled to this surface 1.
  • the surface 1 created by the grinding has been selected in a ratio of 0.02: 1 to the diameter of the glass rod, so that the overall arrangement is optimized here.
  • the glass rod 4 is embedded in a protective outer tube 5 by contact-free mounting of the end faces 2 on two mounting elements 6 with suitable dimensions.
  • To couple the fiber 3, it is first arranged centrally in a tube 7, the outer radius of which corresponds to that of the tube 5, and ground on the end face.
  • a fiber holder 8, adhesive 9 and a fiber sheathing 10 serve to embed the fiber 3 in the tube 7.
  • Fiber 3 and glass rod 4 are suitably adjusted and glued or fused together.
  • the end not used for coupling is closed by means of a plug 11.
  • the bearing on the end faces can be omitted.
  • a single-mode fiber z. B. an extended multimode fiber is also suitable.

Landscapes

  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Molecular Biology (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Measurement Of Radiation (AREA)
  • Photometry And Measurement Of Optical Pulse Characteristics (AREA)
  • Glass Compositions (AREA)

Abstract

Ce capteur de mesure d'une dose de rayonnement équivalente au tissu comprend une fibre optique (4) sensible aux rayonnements, des moyens (1, 3) pour coupler la lumière à la fibre optique (4) sensible aux rayonnements et pour l'en découpler, et des couches réfléchissantes (2) appliquées sur les deux extrémités de la fibre optique (4) sensible aux rayonnements. La lumière qui pénètre dans la fibre optique (4) sensible aux rayonnements est réfléchie plusieurs fois en avant et en arrière, de façon à allonger le parcours de la lumière par rapport aux capteurs classiques. Il résulte du parcours allongé de la lumière une sensibilité améliorée qui ne réduit pas pour autant la résolution spatiale.
EP96946337A 1995-12-02 1996-12-02 Capteur de mesure d'une dose de rayonnement equivalente au tissu Withdrawn EP0864106A2 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19545060A DE19545060C1 (de) 1995-12-02 1995-12-02 Sensor zur Messung einer gewebeäquivalenten Strahlendosis
DE19545060 1995-12-02
PCT/DE1996/002321 WO1997021112A2 (fr) 1995-12-02 1996-12-02 Capteur de mesure d'une dose de rayonnement equivalente au tissu

Publications (1)

Publication Number Publication Date
EP0864106A2 true EP0864106A2 (fr) 1998-09-16

Family

ID=7779066

Family Applications (1)

Application Number Title Priority Date Filing Date
EP96946337A Withdrawn EP0864106A2 (fr) 1995-12-02 1996-12-02 Capteur de mesure d'une dose de rayonnement equivalente au tissu

Country Status (4)

Country Link
US (1) US6041150A (fr)
EP (1) EP0864106A2 (fr)
DE (1) DE19545060C1 (fr)
WO (1) WO1997021112A2 (fr)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19857502A1 (de) * 1998-12-14 2000-06-15 Forschungszentrum Juelich Gmbh Erhöhung der Strahlungsempfindlichkeit einer Glasfaser
FR2826733B1 (fr) * 2001-07-02 2003-09-05 Commissariat Energie Atomique Capteur de rayonnement, a compensation d'energie et grande ouverture angulaire, pour la dosimetrie a distance, et dispositif de dosimetrie utilisant ce capteur
US7399977B2 (en) * 2004-07-23 2008-07-15 University Health Network Apparatus and method for determining radiation dose
US9000401B2 (en) 2010-07-07 2015-04-07 Institut National D'optique Fiber optic radiochromic dosimeter probe and method to make the same
US9354327B1 (en) * 2014-01-22 2016-05-31 Lockheed Martin Corporation Radiation detection package

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3234900A1 (de) * 1982-09-21 1984-03-22 Siemens Ag Faseroptischer sensor
GB2200984B (en) * 1986-12-16 1990-11-07 Optical Data Communications Lt Fibre optic ionising radiation detector
DE3929294A1 (de) * 1989-09-04 1991-03-14 Forschungszentrum Juelich Gmbh Verfahren und messeinrichtung zur messung der dosis bzw. dosisleistung von kernstrahlung
FR2718852B1 (fr) * 1994-04-19 1996-05-15 Commissariat Energie Atomique Dispositif de détection à distance de rayonnement.
DE19503647C2 (de) * 1995-02-06 1999-12-16 Forschungszentrum Juelich Gmbh Meßvorrichtung zur in-vivo und on-line-Bestimmung der gewebeäquivalenten Dosis bei der Strahlentherapie

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9721112A3 *

Also Published As

Publication number Publication date
US6041150A (en) 2000-03-21
WO1997021112A2 (fr) 1997-06-12
WO1997021112A3 (fr) 1997-08-21
DE19545060C1 (de) 1997-04-03

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