JP6083801B2 - Near-infrared imaging device calibration phantom - Google Patents

Description

  The present invention relates to a near-infrared imaging device calibration phantom.

(Current status of noninvasive diagnostic imaging)
In recent years, the development of noninvasive diagnostic imaging methods has been remarkable in the fields of medicine and animal experiments. Examples of diagnostic imaging methods include computed tomography (CT) such as μCT, positron emission tomography (PET), and near-infrared spectroscopy (NIRS).

  Among these, NIRS is a technology that has been developed and spread rapidly in recent years, although its history is shallow compared to μCT and PET. This NIR method may be used alone, but in advanced research areas, NIRS is combined with other noninvasive diagnostic techniques such as PET to evaluate multiple parameters (multimodality diagnosis). Has been. A device that captures the reaction (oxygen state) of a living body or animal using this NIRS and performs color mapping display of the oxygen state in real time is called a near-infrared imaging device (hereinafter also referred to as an NIR device).

(NIR equipment calibration phantom and its necessity)
However, in the field of diagnostic imaging using an NIR apparatus, a calibration phantom such as that used in an X-ray diagnostic apparatus has not been put into practical use. This calibration phantom is (1) when you want to quantitatively evaluate the change over time of the same diagnosis target with the same NIR device, and (2) when you are experimenting under the same conditions (for example, animal experiments) with different NIR models This is a device for standardizing detected output data when there is no difference in the detection results (detected output values) of each device. It should be a “common ruler” or “standard” when used.

  For example, when diagnosing the same diagnosis target (for example, animal) over time using the same NIR device (that is, in the former case), a slight change in temperature and humidity around the NIR device, There is a concern that the detection value of the apparatus may fluctuate due to a change in the light source irradiation ability in a model equipped with a xenon lamp or a mercury lamp.

  On the other hand, when performing the same experiment with NIR devices manufactured by different manufacturers (ie, the latter case), it is only a qualitative comparison of the data measured directly from each device. If standardized data can be obtained by correcting actual measurement data using, it will be possible to compare data more accurately and quantitatively, which will greatly contribute to data sharing, analysis, and phenomenon elucidation among researchers. It is expected to make a significant contribution.

(About conventional phantoms)
As described above, there is no practical or commercially available phantom in the field of NIR diagnostic imaging. It is also unclear whether even the idea of phantoms aimed at standardizing data between different models has been proposed.

(Barriers to the Practical Use of Phantoms 1. Storage period of fluorescent dyes)
By the way, the fluorescent dye enclosed in the NIR device calibration phantom is relatively less attenuated than fluorescent dyes such as fluorescein isothiocyanate (FITC), which are used in fluorescent microscopes and have a short excitation / fluorescence wavelength. It is said to have physical properties. However, when the outer shape of the phantom is made of a material that transmits light, the period in which this fluorescent dye can be stored becomes extremely short, which hinders quantitative evaluation of changes over time of the diagnosis target by the NIR device, As a result, there is concern that it may become a barrier to the practical application of phantoms.

(Barriers to practical use of phantoms 2. Induction of scattered light and blur from phantoms)
On the other hand, producing a phantom with a material that exhibits a behavior close to the optical behavior of animal tissue or living organ tissue has a great advantage in simulating the entire object to be measured. However, when using a phantom made of only such materials, it will induce scattered light and blur that would be observed when an actual animal or living body is measured with an NIR device. Reproducibility can be unstable. This destabilization of data reproducibility can also be a factor that hinders the practical use of phantoms for the original purposes of data calibration and data standardization.

(Barriers to practical use of phantoms 3. Understanding optical characteristics of each NIR device)
Furthermore, the present inventors have clarified the optical characteristics of each NIR apparatus to be used (that is, for each model) and felt the necessity and problem of improving the accuracy of quantitativeness obtained by each apparatus. More specifically, the present inventors have noticed the need for a phantom capable of obtaining a calibration curve related to optical characteristics for each model used. No phantom that satisfies these requirements has been found so far, and in the first place, the idea itself of verifying the above points in advance using a phantom has not been found.

  In addition, although the following patent documents 1-3 are mentioned as a conventional optical phantom, it does not aim at the solution of the said subject.

  Patent Document 1 is mainly intended to provide a phantom that faithfully represents a living organ (specifically, the brain) having a complicated shape and optical characteristics. Long-term storage of fluorescent dyes enclosed in the phantom and There is no disclosure or suggestion of any special measures or ingenuity regarding destabilization of data reproducibility. In addition, since the said phantom cannot be utilized if a to-be-measured object becomes another living organ or animal, you have to produce a phantom for every to-be-measured object.

  Patent Document 2 mainly aims to provide a phantom that faithfully represents a mammalian tissue (specifically, a mouse) as in Patent Document 1, and long-term storage and data storage of fluorescent dyes enclosed in the phantom. There is no disclosure or suggestion of special measures or ingenuity regarding instability of reproducibility. In addition, since the said phantom cannot be utilized if a to-be-measured object becomes another living organ or animal, you have to produce a phantom for every to-be-measured object.

  Patent Document 3 relates to a phantom used when adjusting an optical CT apparatus. In particular, since the optical CT apparatus scans the periphery of the human body (with its body) with a light beam, Patent Document 3 aims to provide a phantom having a multilayer structure in which the absorbance differs in the thickness direction (radial direction). It is said. In order to solve this object, a multi-layer phantom is disclosed in which the types and amounts of light scattering materials (specifically kaolin) and pigments (specifically phthalocyanine blue) are different. As described above, the purpose of the phantom disclosed in Patent Document 3 is different from the above-described problem in the present invention, and the configuration of the phantom is naturally different from the configuration of the phantom proposed in the present invention. is there.

JP 2000-089663 A Special table 2008-522158 gazette Japanese Patent No. 2575900

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a near-infrared imaging device calibration phantom that is capable of long-term storage of an encapsulated fluorescent dye and is less likely to induce scattered light and blur. And

  Furthermore, another object of the present invention is to provide a phantom capable of quantitatively evaluating the optical characteristics of the near-infrared imaging apparatus.

  As a result of diligent research, the present inventors have made a path (path) in which light is incident on the phantom from the light source of the near-infrared imaging apparatus and reflected back to the detector in the phantom, that is, the target (phantom ) Was focused on the path (light source-target-detector) connecting the light source to the detector via). The inventors of the present invention have a light-transmitting material similar to the light-transmitting property of an actual object to be measured (animal tissue) only in a part of the phantom structure that constitutes a part of the path. On the other hand, the present inventors have found that a phantom capable of solving the above-described problems can be provided by installing a light-impermeable material in other portions, and the present invention has been completed.

  That is, the present invention has the following configuration / features.

(Aspect 1)
A main body having at least an outer surface made of a light-impermeable resin or a light-impermeable hard rubber;
A cylindrical opening extending from the upper surface of the main body toward the lower surface;
A fluorescent dye housed in the cylindrical opening;
A cap that has light permeability similar to that of biological tissue or animal tissue and covers the cylindrical opening;
And having
At least three or more cylindrical openings are installed in the main body,
The cap is silicone rubber; and
The cap is installed in a number corresponding to the installation number of the cylindrical opening,
A near-infrared imaging device calibration phantom characterized in that either the thickness of the cap or the concentration or amount of the fluorescent dye is changed.
(Aspect 2)
The main body has a plurality of arrays of at least three or more cylindrical openings,
In the first array, either the thickness of the cap or the concentration or amount of the fluorescent dye is set to change,
The phantom according to aspect 1, wherein the second array is set so that a parameter different from the parameter set in the first array changes among the parameters.
(Aspect 3)
3. The phantom according to aspect 2, wherein the main body has a third array set so that a parameter different from the parameters set in the first and second arrays among the parameters is changed.
(Aspect 4)
4. The phantom according to any one of aspects 1 to 3, wherein the resin or the hard rubber of the main body is a black resin or a black hard rubber.
(Aspect 5)
The phantom according to any one of aspects 1 to 4 , wherein a viscous liquid is further injected into the cylindrical opening so as to enclose the fluorescent dye.

  According to the near-infrared imaging device calibration phantom having the above configuration, the cap and the cylindrical opening containing the fluorescent dye in the phantom have a path connecting the light source to the detector of the near-infrared imaging device. This corresponds to a part, and light can be incident from a light source and reflected toward a detector in the same manner as when measuring an object to be measured such as a mammal.

  In addition, since most of the phantom body is selected from light-opaque materials, it can induce long-term storage of fluorescent dyes enclosed in the phantom, and induces scattered light and blur when irradiating the phantom with light. Can be prevented as much as possible.

  Furthermore, according to the phantom of the present invention, at least three cylindrical openings are installed in the main body, the number of caps corresponding to the number of installed cylindrical openings is installed, and the thickness of each cap or each fluorescent light Either the concentration or the amount of the dye is set to change. This makes it possible to quantitatively evaluate the optical characteristics of the near-infrared imaging device (for example, a calibration curve related to the above parameters and fluorescence intensity). Furthermore, quantitative comparison of data obtained between different models is possible.

  Furthermore, according to a preferred aspect of the present invention, a viscous liquid (for example, a gelling agent such as an alginate gel) is further injected into the cylindrical opening so as to enclose the fluorescent dye. Thus, it is possible to maintain a fluorescence intensity comparable to (that is, moderate) the fluorescence intensity when the fluorescent dye is sealed in the aqueous solution.

1 is an exploded perspective view showing a phantom of Example 1. FIG. It is the perspective view and top view which showed the phantom of Example 1. FIG. It is sectional drawing fractured | ruptured by each broken line of FIG. It is the figure which showed the external appearance of the whole phantom (prototype) of Example 2, and the external appearance of each cap on a 1st array. It is the figure which showed the verification test result (time-dependent change of fluorescence intensity) of Example 2. FIG. It is the figure which showed the verification test result (two-dimensional distribution of fluorescence intensity) of Example 2.

  Hereinafter, although the present invention is explained based on the example shown in a drawing, the present invention is not limited to the following concrete example at all. In the drawings, the same reference numerals are used for the same or corresponding elements.

(Phantom structure of Example 1)
1 to 3 are diagrams showing a configuration of a near-infrared imaging device calibration phantom 1 according to the first embodiment. In particular, FIG. 1 is an exploded perspective view of the phantom 1 showing a state in which a cap 20 (specifically, a plurality of caps 20 a to 20 j) that is a constituent member of the phantom 1 is separated from the main body 10. On the other hand, FIG. 2 is a perspective view and a plan view of the phantom 1 showing a state in which these constituent members 10 and 20 are assembled. Further, each drawing in FIG. 3 is a cross-sectional view taken along the broken lines (AA ′ line and BB ′ line) in FIG.

(Phantom body)
First, the phantom 1 of the present invention includes a main body 10 having at least an outer surface 11 made of a light-impermeable resin or a light-impermeable hard rubber. Here, the outer surface 11 means the upper and lower surfaces 11a and 11b and the four side surfaces 11c to 11f, and may further include a main body outer edge portion having these surfaces 11a to 11f.

  In addition, all the parts (all except the cylindrical opening part 13 mentioned later) of the main body 10 may be made from light-impermeable resin or light-impermeable hard rubber. The resin or hard rubber is preferably a black resin or a black hard rubber, and more preferably a black resin from the viewpoint of excellent productivity and moldability. In particular, the black color is most preferably a matte black color, for example, matte-black, in order to exhibit the light-opacity of the main body 10 satisfactorily. The coloring of the resin can be realized by adding a black pigment or dye to the transparent resin.

(Cylindrical opening)
Further, the main body 10 is provided with a plurality (at least three or more) of cylindrical openings 13 extending from the upper surface 11a toward the lower surface 11b and capable of accommodating the fluorescent dye 12. In the illustrated example, these openings 13 have a cylindrical shape extending in the depth direction of the main body 10 (that is, the vertical direction), and the inner diameters are substantially the same along the axial direction.

  The cylindrical opening 13 receives a flange portion 21 (see, for example, 21a) of a cap 20 (see 20a in the example shown in FIGS. 1 and 3A), which will be described later, and the cap 20's The cap support part 14 (for example, refer to 14a) which prevents a fall may be provided. In the illustrated example, the cap support portion 14 is a cylindrical space having an inner diameter slightly larger than the inner diameter of the cylindrical opening 13, and a level difference caused by the difference between the inner diameter of the cylindrical space and the inner diameter of the cylindrical opening 13. The (shoulder portion) supports the flange portion 21 of the cap 20 and prevents the cap 20 from falling. Furthermore, if the height of the cap support portion 14 is set to be the same as the height of the flange portion 21, the upper surface of the flange portion 21 and the upper surface 11a of the main body 10 are flush with each other, and undesirable scattered light is generated. It becomes possible to prevent.

(Fluorescent dye)
Here, the fluorescent dye 12 accommodated in the cylindrical opening 13 will be described with reference to FIGS. 3 (a) and 3 (b). The fluorescent dye 12 may be a dye having an excitation wavelength and an emission wavelength in the vicinity of 600 nm to 900 nm when light such as laser light is irradiated from the light source 31 that is usually installed in the NIR apparatus. Not only the fluorescent dye 12 but also a material labeled with the fluorescent dye 12 (for example, bisphosphonate or pamidronate) may be used.

(Encapsulation of fluorescent dye)
On the other hand, as for the method of encapsulating the fluorescent dye 12, a method in which the fluorescent dye 12 is soaked in a normal filter paper (not shown) and placed in the cylindrical opening 13, the fluorescent dye 12 and water (not shown) And the like, and a method of injecting the fluorescent dye 12 in an aqueous solution state into the cylindrical opening 13 can be considered, but is not necessarily limited thereto. Further, instead of the latter water, the gel-like fluorescent dye 12 in which the fluorescent dye 12 is sealed with the liquid 15 having a transparent or translucent viscosity is injected into the cylindrical opening 13. Good.

  Here, the viscous liquid 15 includes a gelling agent such as an alginate gel demonstrated in Example 2 described later as a suitable example, but is not limited to this example. For example, hyaluronic acid, chondroitin sulfate, polyethylene glycol (PEG) and the like are also promising.

  When filter paper is used, it should be noted that the fluorescence intensity of the fluorescent dye 12 may be remarkably enhanced depending on the type and amount of the bleach contained in the filter paper when measured with a NIR apparatus. It is. On the other hand, the fluorescence intensity of the fluorescent dye 12 in the aqueous solution state is kept substantially constant. Furthermore, the fluorescent dye 12 enclosed with the viscous liquid 15 can exhibit the same fluorescent intensity as the fluorescent dye 12 in the aqueous solution state, and the fluorescent dye in the cylindrical opening 13. Therefore, it is suitable for further stabilization of fluorescence intensity, prevention of damage to the fluorescent dye 12, and long-term storage. Further, when the liquid 15 having a viscosity is used, the fluorescent dye 12 can be distributed uniformly in the vicinity of the bottom surface of the cylindrical opening 13 (evenly), and the detection by the NIR apparatus is possible. The detection error in the instrument can be reduced as much as possible.

(cap)
Furthermore, the phantom 1 of the present invention is provided with a plurality of caps 20 having light permeability similar to that of living tissue or animal tissue and covering the cylindrical opening 13 in addition to the main body 10 described above. As shown in the drawing, each cap 20a to 20j has a cylindrical shape so that the above-described fluorescent dye 12 and viscous liquid 15 can be sealed in the cylindrical opening 13 at the manufacturing stage of the phantom 1. You may install in the opening part 13 so that attachment or detachment is possible. However, when the phantom 1 is used in the NIR apparatus, the caps 20a to 20j are usually firmly fixed to the cylindrical opening 13.

  The illustrated cap 20 has a shape corresponding to the cylindrical opening 13, that is, a solid cylindrical cap main body 22 (see 22 a and 22 f shown in FIG. 1), and a collar portion further extending from the cap main body 22 in the outer peripheral direction. 21 (see 21a and 21f shown in FIG. 1). Since the flange portion 21 is supported by the cap support portion 14 of the main body 10 (see 14a and 14f shown in FIGS. 3A and 3B), the cap 20 is dropped into the cylindrical opening portion 13. Instead, it is fixed at a predetermined position. Moreover, the collar part 21 may be partially cut off (see 23a in FIG. 1), and when the cap 20 is loaded into the cylindrical opening part 13, the gap between the collar part 21 and the cap support part 14 is obtained. A slight gap G (see FIG. 2B) can be created. Since the operator's fingernail (not shown) and the tip of the tweezers (not shown) can be inserted into the gap G, the cap 20 can be easily attached and detached when the phantom 1 is manufactured.

(Cap material)
Here, as a material of the cap 20 having light permeability similar to that of living tissue or animal tissue, for example, silicon rubber may be used. Preferably, it is a transparent or translucent silicon rubber, and more preferably a semi-transparent (white cloudy) silicon rubber having a relatively smooth surface. As the smoothness of the surface of the cap 20, when the average height when the surface is measured at 10 points is expressed as Rz, Rz ≦ 5 μm is preferable, and Rz ≦ 3 μm is more preferable.

(Light entry direction and path between light source or detector and phantom)
The phantom 1 of the present invention is completed by attaching the above-described cap 20 to the cylindrical opening 13 enclosing the above-described fluorescent dye 12. As shown in FIG. 3 (a), the phantom 1 of the present invention has a path where light enters the phantom 1 from the light source 31 of the NIR apparatus, that is, a path P1 and a path P2 where light returns from the phantom 1 to the detector 32. Only light transmissive materials (cap 20, fluorescent dye 12, air layer 16, water (not shown), viscous liquid 15 etc.) are allocated, and other parts are light transmissive A configuration in which a raw material (that is, a material of the main body 10) to be assigned is assigned.

  As a result, the phantom 1 can receive light from the light source 31 and reflect the light toward the detector 32 in the same manner as when measuring an actual mammal (not shown) or the like with the NIR device. Furthermore, since the light-impermeable material is selected for the portions other than the portions that contribute to the light incident and reflection paths P1 and P2, the fluorescent dye 12 enclosed in the phantom 1 can be stored for a long time. , It is possible to prevent scattered light and blur from the phantom 1 as much as possible.

(Multiple detection areas)
Further, as described above, at least three cylindrical openings 13 are installed, and the number of caps 20 corresponding to the number of installed cylindrical openings 13 is also installed. That is, when the phantom 1 is measured by the NIR apparatus, the detection area is plural (three or more, ten in the first embodiment).

(Detection area array arrangement)
Further, in the illustrated example, five cylindrical openings 13 and caps 20 form a row (hereinafter also referred to as an array), and a plurality (two) of the arrays are arranged (FIG. 2). (See A1 and A2 shown in (b)). As shown in FIGS. 1 and 3A, in the first array A1, the thickness t of the cap 20 (20a to 20e) is set to change. On the other hand, in the second array A2, it is noted that the parameter (that is, the concentration of the fluorescent dye 12) different from the parameter (that is, the thickness t of the cap 20) set in the first array A1 is changed. I want to be.

  Further, although not shown, the main body 10 may further be formed with a third array in which at least three or more cylindrical openings 13 form a row, and the parameters (caps) given by the first and second arrays A1 and A2 may be formed. It should be noted that different parameters (that is, the amount of the fluorescent dye 12 to be injected) are set to be different for each cylindrical opening 13 (thickness t of 20 and the concentration of the fluorescent dye 12).

  In order to change the amount of the fluorescent dye 12, the depth (that is, the volume) of each cylindrical opening 13 may be changed while the thickness t of the cap 20 remains constant, or each cylindrical opening 13 may be changed. Alternatively, the injection amount of the fluorescent dye 12 may be made different from each other after sufficiently securing the depth of each. In the latter case, a gap (for example, an air layer 16) may be generated between the fluorescent dye 12 or the viscous liquid 15 and the bottom of the cap in the cylindrical opening 13 closed by the cap 20. .

  In the illustrated example, two arrays A1 and A2 are shown, but only at least one array may be installed. If there are other parameters (for example, different types of fluorescent dyes) that cause a change in fluorescence intensity when the phantom 1 is irradiated with light from the NIR apparatus, four or more arrays are installed as necessary. You may do it.

(Advantages of multiple detection areas)
When at least three or more cylindrical openings 13 and caps 20 (that is, detection areas) in which the above parameters are changed are installed in the main body 10, the phantom 1 of the present invention exhibits the following advantages and effects. To come.

  That is, once light is irradiated from the NIR device toward the phantom 1, the fluorescence intensity obtained from at least three detection areas changes under the influence of the above parameters. Accordingly, it is possible to quantitatively derive the relationship between the parameter and the fluorescence intensity (for example, a calibration curve). This makes it possible to quantitatively evaluate the optical characteristics of the NIR device (for example, a calibration curve related to the above parameters and fluorescence intensity). Furthermore, quantitative comparison of data obtained between different NIR models is also possible.

(Phantom prototype)
The phantom 1 of the present invention was actually made on a trial basis and the fluorescence performance was verified (this prototype is also referred to as the phantom 1 of Example 2). 4A shows the appearance of the entire phantom 1 of the second embodiment, and FIG. 4B shows the appearance of the caps 20a to 20e on the first array A1.

(Main body of Example 2)
As shown in FIG. 4A, the main body 10 is made of a resin material exhibiting black (matte black) (specifically, polyacetal (polyoxymethylene; POM), which is a kind of thermoplastic resin). Was processed into 40 mm × 80 mm × 22 mm in length × width × height so as to approximate the trunk size of a nude mouse. Polyacetal is known not only as a material with excellent workability, impact resistance and wear resistance, but also as a material with low water absorption and moisture absorption and excellent solvent resistance. Suitable as a material.

(Cylindrical opening of Example 2)
Furthermore, a total of ten cylindrical openings 13 extending in the depth direction (downward in the vertical direction) from the upper surface 11a were formed in the main body 10 by drilling. Of these, the five cylindrical openings 13 constitute the first array A1, and the remaining five cylindrical openings 13 constitute the second array A2.

  The cylindrical openings 13 on the first array A1 are cylindrical holes each having a diameter of 6 mm and a depth of 20 mm from the upper surface. The cap support portions 14 on the first array A1 are cylindrical holes each having a diameter of 8 mm and a depth of 0.8 mm from the upper surface 11a and provided coaxially with the central axis of the cylindrical opening 13. is there. On the other hand, the cylindrical openings 13 on the second array A2 are cylindrical holes each having a diameter of 6 mm and a depth of 2 mm from the upper surface 11a. The cap support part 14 on the second array A2 has the same dimensions and configuration as the cap support part 14 on the first array A1.

(Cap of Example 2)
The cap 20 (20a to 20j) that can be detachably attached to the cylindrical openings 13 on the first and second arrays A1 and A2 is made of translucent silicon rubber having a smooth surface. did. The caps 20a to 20e on the first array A1 have the same diameter (6 mm) but have different lengths (1 mm, 2 mm, 4 mm, 8 mm, 16 mm). On the other hand, the caps 20f to 20j on the second array A2 were used having the same diameter (6 mm) and length (1 mm). Further, the caps 20a to 20j on the first and second arrays A1 and A2 are provided with a cylindrical flange portion 21 having a diameter of 8 mm and a thickness of 0.8 mm. Each collar 21 has a surface from which a part of the cylinder is cut so as to form a gap G when installed in the cylindrical opening 13.

(Fluorescent dye of Example 2)
The fluorescent dye 12 of Example 2 is labeled with one having excitation and emission wavelengths of 680 ± 10 nm and 700 ± 10 nm, specifically, pamidronate (trade name; Osteosense, manufacturer VisEn Medical, Inc.). Dye was used. This fluorescent dye 12 was prepared by mixing an equal amount of 5% sodium alginate and 2% calcium chloride hydrate (CaCl ₂ · 2H ₂ O) in a 2.5% alginate gel. ) In a state of being enclosed in 15, it was accommodated in the cylindrical opening 13 on the first array A1. In this verification test, it was confirmed that the concentration of the alginate gel 15 is preferably 1 to 3%.

  After the cap 20 is loaded into each cylindrical opening 13 containing the fluorescent dye 12, the very thin plate transparent file (not shown) is further pasted on the upper side of the cap 20, and the fluorescent dye 12 or alginate is attached. The evaporation of moisture from the gel 15 was suppressed as much as possible.

(Phantom performance verification test)
As described above, the temporal change in the fluorescence intensity of the phantom 1 in which the fluorescent dye 12 was housed was verified using the NIR apparatus. During the storage period other than measurement, the phantom 1 was wrapped in aluminum foil and stored in a refrigerator at 4 ° C.

  FIG. 5 shows the change over time of the fluorescence intensity (arbitrary unit; au) obtained by the above test. Here, the test condition was the thickness of the cap 20. Under the condition of 0 mm, the cylindrical opening 13 was covered with only the transparent film for plates without being loaded with the cap 20.

  As is clear from FIG. 5, the fluorescence intensity under any of the test conditions was not stable for several days from the start of the test, but a substantially constant fluorescence intensity was obtained for at least two months after one week. In addition, a slight increase or decrease in the data (fluorescence intensity) was observed depending on the measurement date. This suggests that changes in the environment such as temperature and humidity may affect the data even if the NIR equipment is the same.

  FIG. 6 shows a two-dimensional distribution (arbitrary unit: au) of fluorescence intensity in which a part of the fluorescence signal detected from the phantom 1 on the 45th day is represented by a pseudo rainbow using the NIR apparatus. The portion indicated by the arrow M (see FIG. 6) shows the strongest fluorescence intensity. Table 1 below shows the fluorescence intensity calculated based on each image in FIG.

  From the results shown in FIG. 6 and Table 1, it was found that when the cap 20 having a length of 4 mm or more was loaded into the cylindrical opening 13, no significant difference was obtained in the pseudo rainbow in the NIR apparatus. As a result, when measuring a living body or animal using the NIR device, the measurement result at a depth of less than 4 mm is sufficient for quantitative evaluation, and the measurement result at a depth greater than that is not suitable for qualitative evaluation. It can be handled as something that does not contribute to the quantitative evaluation of what contributes.

  It should be noted that fluorescent dyes 12 having different concentrations were injected into the cylindrical openings 13 on the second array A2 to change the fluorescence intensity over time. Although not shown, it was confirmed that different fluorescence intensities could be obtained according to changes in concentration.

  In recent years, the development of noninvasive diagnostic imaging techniques has been remarkable and is being adopted in various fields including cell therapy and navigation surgery. Against this background, using the near-infrared imaging device calibration phantom of the present invention not only enables long-term storage of the encapsulated fluorescent dye, but also has the advantage of being less likely to induce scattered light and blur. Is obtained.

  Furthermore, since the phantom of the present invention can quantitatively evaluate the optical characteristics and detection capability of the near-infrared imaging device, it not only contributes to further data reliability evaluation, but also standardizes the data, and thus between different devices. Enable data sharing.

  Thus, the phantom of the present invention has very high industrial utility value and applicability.

DESCRIPTION OF SYMBOLS 1 Phantom for near infrared imaging apparatus calibration 10 Main body 11 (11a-11f) Outer surface of main body 11a Upper surface of main body 11b Lower surface of main body 11c, 11d, 11e, 11f Side surface of main body 12 Fluorescent dye 13 Cylindrical opening 14 Cap support Part 15 Liquid with viscosity (alginate gel)
16 Air (Air layer)
20 (20a-20j) Cap 21 Cap collar 22 Cap body 31 Light source of near-infrared imaging device 32 Detector of near-infrared imaging device A1 Detection area consisting of cylindrical opening, cap, and fluorescent dye 1 array A2 2nd array of detection area consisting of cylindrical opening, cap, and fluorescent dye P1 Path of incident light from light source to phantom
Path of reflected light from P2 phantom to detector
t Cap thickness

Claims (5)

A main body having at least an outer surface made of a light-impermeable resin or a light-impermeable hard rubber;
A cylindrical opening extending from the upper surface of the main body toward the lower surface;
A fluorescent dye housed in the cylindrical opening;
A cap that has light permeability similar to that of biological tissue or animal tissue and covers the cylindrical opening;
And having
At least three or more cylindrical openings are installed in the main body,
The cap is silicone rubber; and
The cap is installed in a number corresponding to the installation number of the cylindrical opening,
A near-infrared imaging device calibration phantom characterized in that either the thickness of the cap or the concentration or amount of the fluorescent dye is changed. The main body has a plurality of arrays of at least three or more cylindrical openings,
In the first array, either the thickness of the cap or the concentration or amount of the fluorescent dye is set to change,
2. The phantom according to claim 1, wherein the second array is set so that a parameter different from the parameter set in the first array changes among the parameters.   3. The phantom according to claim 2, wherein the main body has a third array set so that a parameter different from the parameters set in the first and second arrays among the parameters is changed.   The phantom according to claim 1, wherein the resin or the hard rubber of the main body is a resin exhibiting black or a hard rubber exhibiting black. The tubular opening, phantom according to any one of claims 1 to 4, characterized in that had viscous fluid is further injected to encapsulate the fluorescent dyes.