KR20150090375A - Device for radiodetector based on cherenkov radiation - Google Patents

Abstract

The present invention relates to a device for radiation detector based on Cherenkov radiation, comprising: a radiation-source unit for emitting radiation; a photo-multiplier distribution unit amplifying a Cherenkov light which is radiated from radiation, converting the light to a optical current, and counting a radiation detection signal; a reflective unit which is installed at the lower part of the radiation source unit corresponding to the photo-multiplier distribution unit; and an image output unit for outputting the radiation detection signal. According to the present invention, since the Cherenkov radiating area is expanded, it is possible to detect more sensitive radiation.

Description

≪ Desc / Clms Page number 1 > Device for radiodetector based on cherenkov radiation &

The present invention relates to a radiation detector using a non-linear transparent tube and a reflector to enhance the radiation area on the basis of a cherenkopy radiation, in particular a radiation source such as a beta (beta +, beta-) emitter ⁶⁸ Ga) is contained in a transparent tube together with the medium, and a transparent tube (for example, HPLC) is applied in a parallel-type or a zigzag-type region in the region to be detected corresponding to the photomultiplier tube (PMT) A radiation detector based on a cherenkopf-based radiation which is configured to have a high density by adopting a non-linear shape and a reflector below the detected region to induce the cherenkov radiation to be concentrated by an ultraviolet sensitive photomultiplier tube will be.

Molecular imaging (Molecular Imaging) is a technique that images various phenomena occurring in the living body from the viewpoint of molecular level and provides important clues of disease treatment and in vivo metabolism.

The greatest merit of molecular imaging is that it allows the quantitative analysis of the phenomena that occur at the cellular or molecular level in the living state of the subject to be studied. These types of molecular images include optical imaging using photons of the visible region and infrared region, nuclear imaging using photons generated by the radiation reaction, magnetic resonance Magnetic resonance imaging (MRI) imaging the signal, and computed tomography (CT) imaging the information obtained by projecting the X-ray.

Among these, the optical imaging technique used in the field of molecular / cellular biology has the greatest sensitivity of the image and the application range is the widest in that the image can be obtained quickly without exposure to radiation.

Optical images can be divided into bioluminescence imaging and fluorescence imaging. Luminescence images are images of chemically synthesized light by the metabolic processes occurring in vivo, and luciferase found in Firefly is a typical example. Fluorescence imaging is a method of labeling and imaging fluorescence in a cell, tissue, or organism that absorbs light of a specific wavelength from the outside and emits light of a longer wavelength. Fluorescent molecular imaging emits the most efficient video signal in the near-infrared region where light absorption, scattering, and autofluorescence are minimized in living tissues. Hemoglobin, which is abundant in the blood vessels, absorbs light in the visible light region, while water and fat in the living body mainly absorb light in the infrared region. Therefore, when the near infrared ray fluorescent material is applied to the optical image, the tissue permeability is the most excellent and the actor signal is minimized.

Various fluorescent materials have been developed along with the development of fluorescence imaging devices. The types are classified into organic fluorescent dyes and inorganic fluorescent particles. Organic fluorescent dyes are already fluorescent materials that are widely used in general industrial and molecular / cellular biology research. These organic dyes vary in the excitation wavelength band and the emitted fluorescence wavelength band, and can be selectively used as needed. In addition, since it is easy to adhere to other materials or biomolecules through chemical bonding, application as a target type fluorescent probe is expected. Most organic dyes, however, are not only difficult to observe for a long time due to their low light stability, but also exhibit low solubility in an aqueous solution because they exhibit hydrophobic properties and may cause toxicity to living organisms.

In addition, such organic dyes are combined with biocompatible biomolecules or biodegradable polymer materials and injected into the living body. However, the biocompatibility and side effects due to unstable binding are also problematic. Inorganic fluorescent particles are nano-sized particles which are similar to semiconductors, which are often called quantum dots. They are recently attracting attention in the field of optical imaging due to their excellent optical stability. It emits stable fluorescence even when exposed to light for a long period of time, which is particularly advantageous for observing the differentiation process or in vivo metabolism of a specific cell. These quantum dots emit fluorescence of various colors depending on the size of the particles and excite light in a wide wavelength range. Therefore, it is possible to perform multi-color imaging in which quantum dots of various sizes can be transmitted to different parts and observed at the same time. The drawbacks of QDs are that they are synthesized in an organic solvent. Therefore, in order to be applied in vivo, surface modification with a water-soluble substance is required and particles are aggregated in this process. In addition, since the particle size of organic dyes is comparable to that of organic dyes, it is difficult to transfer into cells and biostability is not confirmed because nuclei of the quantum dots are composed of heavy metals such as cadmium (Cd) and selenium (Se). In recent years, attempts have been made to synthesize relatively stable metals in living bodies instead of heavy metals forming quantum dots and to increase the cell permeability of quantum dots.

However, currently used fluorescent materials have many problems in terms of biocompatibility and particle stability.

On the other hand, nuclear medicine imaging technology allows us to observe many in vivo phenomena that were impossible in the past. In particular, isotope-based radiation imaging technology is widely used from basic biological experiments using animals to clinical use, based on the advantages of high sensitivity, excellent tissue permeability and excellent quantification.

Such radiation detection is widely used throughout the industry, such as medical apparatus such as Computed Tomography (CT) or Positron Emission Tomography (PET), nuclear reactor apparatus, or nondestructive testing apparatus.

Conventional radio-HPLC (High Performance Liquid Chromatography) detectors are mainly used for crystal scintillators or liquid scintillators.

However, solid detectors used in connection with such conventional radioactive high-performance liquid chromatography (HPLC) have a problem that an unintended gamma ray background detection is detected. In particular, there is a problem of pile-up because it does not have a fast fall time.

In addition, these solid detectors are subject to a large amount of radioactivity located around them in the radiation zone in which they are used. To reduce the amount of radioactivity around them, they are thoroughly shielded with lead or tungsten around the detector, There is a limit to detect only the radiation coming from the tube passing under the detector. However, due to the high transmittance of the gamma rays, it is impossible to completely shield the external radiation, and a certain noise background can not be avoided even if a large shield is used.

Recently, a scintillator radiation detector is under research and development. These radiation detectors have a plurality of scintillators attached to the optical fibers, respectively. The role of the optical fiber is to relay the signal out of the beam so as to ensure readout of the signal in an uncontaminated environment by ionizing radiation. A bundle of optical fibers constitutes the inspection head.

Open No. 10-2013-0034137 discloses a radiation detector having a bundle of optical fiber members capable of obtaining a high-resolution image in which no interference or distortion occurs between signals for an image.

However, the above-mentioned scintillator radiation detectors incur a very high manufacturing cost especially in connection with the arrangement of the optical fibers. In addition, the resolution of the radiation detector is greatly limited by the size of each individual scintillator and, for example, the number and diameter of the optical fibers.

Therefore, a new attempt has been made to detect radiation based on cherenkopy without using a fluorescent material and a scintillator. Cherenkov radiation is a cone-shaped light with a constant angle around the incident line when the charged particles pass through the medium at a velocity higher than the velocity of light in the medium.

Despite the fact that such cherenkopf radiation is more sensitive to radiation detection, there is a disadvantage in that a more powerful radiation detection signal can not be obtained because the actual Chernkopi radiation area is not large.

Korea Publication No. 10-2013-0034137

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a radiation detector based on a cherenkopy radiation whose gamma-ray background noise is minimized.

It is another object of the present invention to provide a radiation detector that applies high-performance liquid chromatography (HPLC), which has been used only for solid detectors, to Chernenkopy radiation.

It is another object of the present invention to provide a cherenkopy radiation-based radiation detector capable of low intensity isotope measurement for more sensitive radiation detection.

It is still another object of the present invention to provide a radiation detector that receives and detects a radiation source in a high-density form in order to further enlarge the radiation area of Cherenkov.

According to an aspect of the present invention, a radiation detector of the present invention includes a radiation source for emitting radiation, a photodetector for amplifying cherenkov light radiated from the radiation, converting the light into a photocurrent, A reflection part provided at a lower part of the radiation source part corresponding to the light leakage part, and an image output part for outputting the radiation detection signal.

As described above, according to the configuration of the present invention, the following effects can be expected.

First, the use of Cherenkov radiation makes no gamma-ray background noise because there is no flashing.

Second, cherenkopy radiation can solve the file-up problem due to short life cycle.

Third, since the radiation source is accommodated in the tube together with the medium, it is easy to manage and is inexpensive.

Fourthly, since the radiation source is housed in the transparent tube, the amount of chirped radiation can be increased by arbitrarily adjusting the area to be detected.

Fifth, it is economical to increase the chirped copper density by using the reflector.

Sixth, most of the radionuclides used for positron emission tomography (PET), which are currently used in clinical trials, have a cherenkov radiation, and most of the therapeutic radionuclides used for therapeutic radiopharmaceuticals are beta (-) collapse, Its application range is very wide.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing the configuration of a chirp-cop-based radiation detector according to the present invention; FIG.
Fig. 2 is a side view of Fig. 1; Fig.
3 is a block diagram showing the configuration of a chirp-cop-based radiation detector according to the present invention;
4 is a graph showing a linear value of a coefficient according to the radioactivity of the ⁶⁸ Ga isotope according to the present invention.
5 is a graph showing the Cherenkov radiation sensitivity according to the material and thickness of a tube according to the present invention.
6 is a graph showing the range of measurable coefficient values at 300 mV threshold voltage according to the present invention.
7 is a graph comparing the amounts of radioactivity according to the ratio of 0.157 mCi and 0.03 mCi ⁶⁸ Ga isotopes according to the present invention.
FIG. 8 is a graph showing the Cherenkov radiation effect at 80 MHz frequency condition according to the present invention. FIG.

Brief Description of the Drawings The advantages and features of the present invention, and how to achieve them, will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. The dimensions and relative sizes of layers and regions in the figures may be exaggerated for clarity of illustration. Like reference numerals refer to like elements throughout the specification.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a chirp-copf based radiation detector according to the present invention will be described in detail with reference to the accompanying drawings.

Recently, there have been various attempts to combine optical images with nuclear medicine images, which have different advantages and disadvantages. However, in order to obtain both nuclear medical images and optical images from a single image probe, it is necessary to make a hybrid type probe combining fluorescence or bioluminescence probe for radionuclide and optical image for nuclear medicine image.

In contrast to optical imaging, fluorophore or luminescent material must be introduced to emit light, whereas most fluorophores are metal complexes or aromatic organic molecules. Compounds, or quantum dots, and the physicochemical properties of original molecules are often changed, so that there is a limited problem in utilization in vivo.

Accordingly, it was confirmed that the present invention can emit light itself without a fluorescent material for emitting light in the case of a specific radionuclide, and can acquire an optical image by detecting the emitted light. In this case, when the specific radionuclide is used as a contrast agent, the optical image can be easily obtained without addition of the fluorescent material, and the optical image can be obtained in real time without changing the physicochemical properties of the substrate.

To this end, the optical image contrast agent according to an embodiment of the present invention may include a radionuclide which emits particles having energy satisfying the T value of the following formula 1 at the time of radioactive decay.

[Relation 1]

T (keV) ≥ 511 [1 / (1-1 / n2) 1/2 - 1]

Where n is the refractive index of the medium

Specifically, [Equation 1] is an equation concerning a threshold at which the Cerenkov radiated emission can occur. In the case of emitting particles having energy satisfying the T value of [Equation 1], in the radionuclide, Luminescence can occur.

The self-luminescence of the above-mentioned specific radionuclides has a close relationship with the Cherenkov radiation according to the Cherenkov law. Specifically, Cherenkov radiation is a light emitted when a charged particle moves at a speed faster than light in the medium. In other words, when the charged particle moves at a speed faster than light in the medium (when it has kinetic energy), it means that the kinetic energy is converted into light energy by the difference as it falls at the speed of light.

Nuclides emitting high energy β- such as 32P are measured using Cherenkov light known as Cerenkov counting. The threshold for the emission of Chenkovsky radiation can be calculated using Equation 1 above.

For example, water has a refractive index of 1.33, so that when a contrast agent containing a radiating radionuclide of the present invention is injected into a living body, the minimum energies of cherenkopon radiation are 262 keV because the living environment is water. Therefore, when the medium is theoretically water, the positron having energy of 262 keV or more during the decay of the radionuclide, or the radionuclide releasing the beta -particle can emit light through the cherenkapf radiation, and a high sensitivity luminescence detector ) Can be used to detect the emitted light. This indicates that 111In, 99mTc and 35S give weak signals while high energy electrons and positron emitting nuclides like 68Ga, 32P, 124I, 18F, 131I and 64Cu show strong signals.

On the other hand, the particles released upon the collapse of radionuclides have various energy distributions. For example, in case of 18F, since the average energy of emitted particles is 250 keV and the maximum value of emitted energy is 634 keV, the emitted particles have a continuous energy distribution of 0 to 634 keV. [Equation 1] is a formula relating to the minimum energy required to generate light according to the refractive index of the medium. Therefore, when the medium is air (refractive index: 1.0003), the minimum energy required for generating light is 20355 keV. In addition, the maximum emission energy of the radionuclide is only 634 keV, so that light is not emitted as a result. However, when the medium is water (refractive index: 1.33), the minimum energy required to generate light is 262 keV, which is lower than that of air. Particles having an energy of 262 keV or more in the emitted particles are converted into light by the energy of the particles. It is possible to diverge.

In other words, as particles emitted from radionuclides with kinetic energy above the speed of light fall at the rate of light, the kinetic energy of that difference is converted into light energy. On the other hand, when the medium has a refractive index higher than that of water (refractive index: 1.52), the minimum energy required to generate light is 168 keV, which is less than that of water. Particles having an energy of 168 keV or more out of the particles, So that light can be emitted. In the above-mentioned example, when the medium is water or glass, the light emission phenomenon occurs, but since the refractive index of the glass is lower than that of the water having a low refractive index, the minimum energy required for generating light is small. Energy can be converted into light, and the amount of light eventually increases.

Hereinafter, the specific means and method of detecting the cherenkopf-based radiation will be described.

1 to 3, a cherenkopy radiation-based radiation detector 100 includes a radiation source 110 for emitting radiation, a light distribution unit 120 for amplifying, converting, and counting cherenkopy light radiated from the radiation, A reflection unit 130 provided below the radiation source 110 corresponding to the light source 200 and an image output unit 140 for outputting a radiation detection signal.

The radiation source 110 includes a radiation source 112, a medium 114, and a transparent tube 116.

The radiation source 112 includes a radiation material that emits radiation. Here, the radiation source 112 includes a beta (beta +, beta-) emitter isotope. For example, a ⁶⁸ Ga isotope. Beta radiation emits charged particles without additional scintillators, so the present invention proposes a detector that quantitatively observes such beta-emitting nuclides with high sensitivity.

The radiation source 110 receives the medium 114 together with the radiation source 112. That is, in order to radiate the cherenkov light by the radiation source 112, the charged particles of the radiation source 112 must have kinetic energy higher than the speed of light in the medium 114 satisfying a predetermined refractive index. Since the Cherenkov light amount is proportional to the refractive index of the medium 114, a medium 114 having an appropriate refractive index can be used. Accordingly, the medium 114 is not particularly limited except for air, and any material other than air can be used as long as a minimum energy value for copying the cherenkov light is ensured.

The transparent tube 116 is a pipe made of a Teflon (fluororesin) material through which the substance to be detected including the radiation source 112 can pass. Since Teflon has characteristics such as almost complete chemical inertness and heat resistance, non-tackiness, excellent insulation stability, and low coefficient of friction by forming a highly stable compound due to strong chemical bonding between fluorine and carbon, the transparent tube 116 is made of Teflon .

Cherenkov radiation is proportional to the refractive index of a medium through which charged particles pass. Since the higher the refractive index is, the more cherenkov radiation can be obtained. Therefore, in the present invention, it is preferable to use a tube having a high refractive index. It is also desirable to use a transparent tube as far as possible so that all generated light can be detected outside the photomultiplier tube (PMT).

Although the transparent tube 116 is a pipe extending in a long direction, the transparent tube 116 is connected in parallel to the region corresponding to the light leakage portion 120 in the present invention, or has a high density characteristic in a zigzag shape extending in series.

The transparent tube 116 may include a high density detected area 116a corresponding to the reflection part 130 and a transfer area 116b for supplying or discharging the radiation source 112 and the medium 114. [ The high-density area 116a can be changed in various forms such as a parallel-type or a zigzag-type in which the path is somewhat complicated as compared with the transfer area 116b, (non-linear).

Alternatively, the transparent tube 116 may be larger in diameter than the transfer area 116b in the high density detected area 116a. For example, since the flow rate of the medium becomes slower from a small diameter pipe to a large pipe, the radiation source 112 in the detected area 116a can be measured at a high density.

Thus, the detector of the present invention can be more usefully applied to the synthesis of radiation, which is the basis for developing radiopharmaceuticals for diagnosis and treatment, by connecting the transparent tube 116, for example, to high-performance liquid chromatography.

The reflector 130 may be a reflector that reflects the cherenkov light radiated to the lower portion of the transparent tube 116 to the upper portion where the light leakage portion 120 is located and prevents the light beams incident from the lower portion. In particular, the reflective portion 130 may be provided at a portion corresponding to the high-density region 116a of the transparent tube 116. [ In the present invention, the reflector is characterized in that the cherenkov light radiated downward of the transparent tube 116 is reflected upward to enhance the radiation detection effect.

 Since the intensity of the cherenkov light radiated from the transparent tube 116 is weak, the diffuser 120 can convert the cherenkov light into electrons and convert the electrons into current pulses proportional to the amount of radiation to effectively perform optical detection have.

Since the output of the light diffuser 120 is much less noise compared to the case of amplifying the output of the light pipe by a transistor or a vacuum tube amplifier in the present invention, a PM-tube suitable for detecting a weak light, But the present invention is not limited thereto, and a silicon photocatalytic pipe (SIPM) or the like may be used. The photomultiplier tube 122 is powered by a high voltage module 124.

On the other hand, a transparent tube of a high refractive index can be simply used as the incident surface of the photomultiplier tube (PMT) through which the Chenkov wave radiation is transmitted. However, it is possible to design a flow cell of various patterns using microfluidic technology so that it can emit a lot of light through a detector part as much as possible.

The diffuser 120 includes a preamplifier 126a for amplifying a radiation detection signal, an inverter 126b for converting DC into AC, a discriminator 126c and a signal counter 126d for counting the radiation detection signal . The signal amplified by the optoelectronic amplifying tube 122 is shaped and amplified by a preamplifier 126a through a BNC cable, converted into an electrical signal capable of detecting the position and energy, and then converted into an electrical signal by using a 32-bit signal counter 126d Converts the analog signal into a digital signal, and inputs the digital signal to the image output unit 140.

The image output unit 140 includes a computer that outputs a radiation detection signal to various images to provide a monitoring function.

The present invention does not exclude broadening the range of detected radionuclides by using them in conjunction with a conventional NaI (Tl) scintillation single crystal detector for radionuclides that do not cause cherenkov radiation or radionuclides that exhibit weak radiolysis.

Hereinafter, a chirp-cop-based radiation detection process according to the present invention will be described.

The beta emitter isotope passing through the transparent tube 116 is accommodated with the medium generating the cherenkopy radiation. Such radiation is detected by the optoelectronic amplifying tube 122, and the detection signal is transmitted to the preamplifier 126a.

This detection signal is amplified by a preamplifier 126a with a bandwidth of 400 MHz, and the amplified cathode signal can not be read by the counter, so that it is converted into a positive signal using the inverter 126b. The amplified signal having a threshold value larger than the threshold value is converted into a TTL (Transistor-Transistor-Logic) signal using the discriminator 126c having a bandwidth of 100 MHz. Subsequently, the signal is counted by a signal counter 126d, such as FPGA logic. This coefficient logic relates to a 32 bit clock edge counter. For example, up to 100 MHz counts / s are available, and time monitoring information via logic is also available.

The above signals are counted for the same interval time. This time can be varied within the range of 1 ms to 1 s. The signal is stored using the FPGA double buffer. Finally, the data is transmitted to a video output unit 140 such as a personal computer using an Ethernet interface and monitored.

Hereinafter, a cherenkopy radiation-based radiation detection experiment according to the present invention will be described with reference to the drawings.

Referring to FIG. 4, it was possible to detect Chernenkorf radiation through the optoelectronimulator tube 122 using a radionuclide ⁶⁸ Ga isotope that emits a beta ray (? +,? -). 189.07 MBq (5.11 mCi) was administered through the transparent tube 116, which corresponds to 0.47 MBq (12.57) considering the radioactivity of the ⁶⁸ Ga isotope passing through the photomultiplier tube 122.

In this experiment, the coefficient value was measured by decreasing the amount of radioactivity to confirm that the coefficient value has a linear value according to the radioactivity amount of the ⁶⁸ Ga isotope passing through the photomultiplier tube 122. The coefficient obtained when the radioactivity of 0.47 MBq (12.57) was passed through the opto-electronic booster pipe 122 was about 100 times the coefficient obtained when 4.81 kBq (0.13) of radioactivity corresponding to about 1/100 thereof was passed . And a radiation intensity of 2.22 kBq (0.06) was passed through the photomultiplier tube 122, about a half of the 4.81 kBq (0.13) coefficient was measured. In FIG. 4, it can be seen that the coefficient value has a linear value according to the radioactivity of the ⁶⁸ Ga isotope.

Referring to FIG. 5, the detection sensitivity of the cherenkov radiation by the material and thickness of the transparent tube 116 passing through the optoelectronic thickening pipe 122 can be confirmed. The transparent tube 116 was made of Teflon FEP having a diameter of 0.5 mm, 0.25 mm, and 0.2 mm, respectively, having a diameter of 1.59 mm, which was used for high performance liquid chromatography, and 1.59 mm outer diameter Teflon-Tetrafluoroethylene-hexafluoropropylene copolymer (Teflon PFA) having an inner diameter of 0.5 mm were used as the thermoplastic polyurethane resin.

The transparent tube 116 is transparent and can transmit light, and the material having higher refractive index and stronger cherenkopy radiation can further increase the sensitivity. The largest Cherenkov radiation was detected in the transparent tube 116 having an inner diameter of 0.5 mm in the Teflon FEP transparent tube 116 as shown in Table 1 below and detected in the Teflon PFA transparent tube 116 having the same inner diameter It was confirmed that the Cherenkov light detected by the Teflon PFA transparent tube 116 was larger than that of the Cherenkov radiation. Therefore, the transparent tube 116 of the present invention preferably has an inner diameter of 0.4 to 0.6 mm and an outer diameter of 1.50 mm to 1.70 mm.

Material (Teflon) Outside diameter (mm) Internal diameter (mm) One FEP 1.59 0.5 2 FEP 1.59 0.25 3 FEP 1.59 0.2 4 PFA 1.59 0.5

Referring to Figure 6, ⁶⁸ Ga In As isotope by measuring the copy cheren Corp. using the transparent tube 116 is installed on the photomultiplier tube 122 inside the dark box for the light barrier, the high voltage module 124 0.0 > (-) < / RTI > bias to the optoelectronic amplifier 122. The threshold voltage of the counter was set at 300 mV. This threshold voltage is effective to avoid background noise, as shown in Fig.

In the above experiment, when the amount of radioactivity of ⁶⁸ Ga, which is passed through the photomultiplier tube 122 using the most sensitive Teflon PFA transparent tube 116, was measured, the coefficient value was small even when 0.26 kBq (0.007) was administered Could.

Referring to FIG. 7, the ratios of 0.157 mCi and 0.03 mCi ⁶⁸ Ga isotopes were compared. For example, when the ⁶⁸ Ga isotope was passed through a photomultiplier tube 122 using a syringe pump and when it was not passed, the radioactivity of the ⁶⁸ Ga isotope was 1.11 kBq (0.03) at 5.8 kBq (0.157) And the time when it was reduced by 1/5 was compared. To check the regeneration ability, we injected 0.157 mCi source twice. After 300 sec, 0.03 mCi beta emitter isotope was added. The results are shown in FIG. It shows 10,000 counts / s when the 0.157 mCi isotope passes through the photomultiplier tube 122. The second test of 0.157 mCi also shows similar results. As a result, it can be seen that 0.03 mCi has a value 5 times smaller than that of 0.157 mCi.

Referring to FIG. 8, the effect of Cherenkov radiation was tested using an agilent function generator. A 50 mV sine pulse was sent to the counter. The frequency was set within the range of 1 MHz to 80 MHz, and the coefficient was set for 1 ms. Figure 8 shows the results at 80 MHz frequency conditions. Because of the high frequency limit of the comparator, the counting rate is in the 1.2% range.

As described above, a single photon counter can measure Chenkrupp's radiation using a ⁶⁸ Ga isotope. It is characterized by the ability to measure low intensity isotopes. In particular, such systems are sensitive to gamma-ray interactions and are therefore useful for minimizing gamma-ray background noise.

As described above, according to the present invention, a cherenkopy radiation is used for more sensitive radiation detection, and a tube for accommodating a radiation source and a medium is formed non-linearly in a detection area in particular, It is understood that it is thought. Many other modifications will be possible to those skilled in the art, within the scope of the basic technical idea of the present invention.

100: radiation detector 110: radiation source
112: source 114: medium
116: Transparent tube 120: Mad dissipation
122: optoelectronic amplifier 124: high voltage module
126a: Preamplifier 126b: Inverter
126c: discriminator 126d: signal counter
130: Reflecting unit 140: Image output unit

Claims (14)

A radiation source for emitting radiation;
A photodiode for amplifying cherenkov light radiated from the radiation, converting the photocurrent into a photocurrent, and counting the radiation detection signal;
A reflection part provided at a lower part of the radiation source part corresponding to the light leakage part; And
And a video output unit for outputting the radiation detection signal. The method according to claim 1,
Wherein the radiation source part comprises a transparent tube of a Teflon (fluororesin) type for receiving a radiation source. 3. The method of claim 2,
Wherein the transparent tube has an inner diameter of 0.4 to 0.6 mm and an outer diameter of 1.5 to 1.7 mm. 3. The method of claim 2,
Wherein said radiation source is contained in said transparent tube with a medium having a predetermined refractive index as a beta (-) emitter isotope. 3. The method of claim 2,
The transparent tube may include:
A detection area corresponding to the reflection part,
And a transfer area for supplying or discharging the radiation source and the medium,
Wherein the region to be detected has a higher density than the transfer region. 6. The method of claim 5,
Wherein the area to be detected is such that the transparent tubes are coupled in parallel. 6. The method of claim 5,
Wherein the area to be detected is such that the transparent tube extends in a staggered manner. 3. The method of claim 2,
Wherein the reflector is a reflector for reflecting the cherenkov light radiated to the lower portion of the transparent tube to an upper portion where the depressed portion is located. The method according to claim 1,
The mad-
A photomultiplier tube for detecting the Cherenkov light;
A preamplifier for amplifying the cherenkov light;
An inverter for converting the cathode signal into a positive signal;
A discriminator for converting an inverter signal into a TTL (Transistor-Transistor-Logic) signal; And
A signal counter for counting the radiation detection signal applied per unit time; Wherein the radiation detector comprises a radiation detector. 10. The method of claim 9,
Wherein the coefficient value of the radiation detection signal has a linear value with respect to the amount of radiation of the radiation source. 11. The method of claim 10,
Wherein the radioactive amount having the minimum coefficient value is at least 0.26 kBq (0.007) when the source is a ⁶⁸ Ga isotope. Wherein the charged particles of the beta emitter isotope contain water to be subjected to kinetic energies above the speed of light,
The to-be-
A delivery region in which the medium is supplied or discharged; And
And a detection area configured to have a higher density than the transmission area. 13. The method of claim 12,
Characterized in that the to-be-detected tube is a transparent tube of Teflon PFA (Teflon PFA), which is a Teflon-Tetrafluoroethylene-Petrifluoroalkylvinylether copolymer (Teflon PFA). 14. The method of claim 13,
The transfer area is linear,
Characterized in that the area to be detected is a non-linear zigzag type radiation detector.

Images