EP0864106A2 - Sensor for measuring a tissue equivalent radiation dose - Google Patents
Sensor for measuring a tissue equivalent radiation doseInfo
- 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- Withdrawn
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.
Abstract
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19545060A DE19545060C1 (en) | 1995-12-02 | 1995-12-02 | Fibre-optic sensor for tissue-equivalent radiation dosimetry |
DE19545060 | 1995-12-02 | ||
PCT/DE1996/002321 WO1997021112A2 (en) | 1995-12-02 | 1996-12-02 | Sensor for measuring a tissue equivalent radiation dose |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0864106A2 true EP0864106A2 (en) | 1998-09-16 |
Family
ID=7779066
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP96946337A Withdrawn EP0864106A2 (en) | 1995-12-02 | 1996-12-02 | Sensor for measuring a tissue equivalent radiation dose |
Country Status (4)
Country | Link |
---|---|
US (1) | US6041150A (en) |
EP (1) | EP0864106A2 (en) |
DE (1) | DE19545060C1 (en) |
WO (1) | WO1997021112A2 (en) |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19857502A1 (en) * | 1998-12-14 | 2000-06-15 | Forschungszentrum Juelich Gmbh | Increasing the sensitivity to radiation of an optical fiber |
FR2826733B1 (en) | 2001-07-02 | 2003-09-05 | Commissariat Energie Atomique | RADIATION SENSOR, WITH ENERGY COMPENSATION AND LARGE ANGULAR OPENING, FOR REMOTE DOSIMETRY, AND DOSIMETRY DEVICE USING THE SENSOR |
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)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3234900A1 (en) * | 1982-09-21 | 1984-03-22 | Siemens Ag | FIBER OPTICAL SENSOR |
GB2200984B (en) * | 1986-12-16 | 1990-11-07 | Optical Data Communications Lt | Fibre optic ionising radiation detector |
DE3929294A1 (en) * | 1989-09-04 | 1991-03-14 | Forschungszentrum Juelich Gmbh | METHOD AND MEASURING DEVICE FOR MEASURING THE DOSAGE OR DOSAGE PERFORMANCE OF CORE RADIATION |
FR2718852B1 (en) * | 1994-04-19 | 1996-05-15 | Commissariat Energie Atomique | Remote radiation detection device. |
DE19503647C2 (en) * | 1995-02-06 | 1999-12-16 | Forschungszentrum Juelich Gmbh | Measuring device for in-vivo and on-line determination of the tissue-equivalent dose in radiation therapy |
-
1995
- 1995-12-02 DE DE19545060A patent/DE19545060C1/en not_active Expired - Fee Related
-
1996
- 1996-12-02 WO PCT/DE1996/002321 patent/WO1997021112A2/en not_active Application Discontinuation
- 1996-12-02 EP EP96946337A patent/EP0864106A2/en not_active Withdrawn
- 1996-12-02 US US09/077,819 patent/US6041150A/en not_active Expired - Fee Related
Non-Patent Citations (1)
Title |
---|
See references of WO9721112A3 * |
Also Published As
Publication number | Publication date |
---|---|
WO1997021112A3 (en) | 1997-08-21 |
WO1997021112A2 (en) | 1997-06-12 |
US6041150A (en) | 2000-03-21 |
DE19545060C1 (en) | 1997-04-03 |
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Legal Events
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