JPH08150135A - Phantom for inspection of organism measuring device - Google Patents

Abstract

PURPOSE: To enable light absorption coefficient and scattering coefficient to be adjusted independently, and also, to enable both to be set accurately, changing the scattering coefficient and the absorption efficient freely, by circulating light absorbing liquid within many tubes, and light scattering liquid outside the tubes, respectively, and passing them measuring sections. CONSTITUTION: A light absorbing liquid supply part 6, a gas exchange part 8 for adjusting the saturation of the oxygen of the light absorber, and a measuring section 10, where the measurement is made by an organism measuring device, are arranged in order along the passage 4 equipped with liquid feed pumps 2a and 2b. And, by adjusting the flow of the pumps 2a and 2b in the light absorbing liquid supply part 6, the concentration of the light absorber of the light absorbing liquid supplied to the passage 4 is adjusted. Moreover, the gas exchange part 8 consists of a gas exchange vessel 30 and a bundle of thin porous pipes 32 which pass therein and allow liquid to pass but do not allow gas to pass through themselves, and light absorbing liquid is circulating in the fine pipe 32, and it is adjusted to light absorbing liquid in desired oxygen saturation by contacting with the gas being adjusted to specified oxygen partial pressure within the gas exchange vessel 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phantom used for verification of a noninvasive biological oxygen monitor and a biometric device such as an optical CT.

[0002]

2. Description of the Related Art In a non-invasive oxygen monitor, in order to verify that the concentrations of oxyhemoglobin and deoxyhemoglobin, which are measured values, and oxygen saturation are correct, the amount of these is known, and the light scattering characteristics are similar to those of the living body. A phantom containing the body and a light absorber is needed. In addition, in the optical CT, in order to evaluate the detection ability of the oxygen supply state distribution in the place of the sample, it is possible to freely create a state in which the oxygen saturation of hemoglobin is different from place to place, and the hemoglobin of the place can be changed. There is a demand for a phantom that can set the concentration and oxygen saturation to desired values.

For these purposes, a liquid phantom composed of a mixed solution of hemoglobin and a light scatterer has been proposed (Pro. Natl. Acad. Sci. USA, Vol. 85, pp. 497).
1-4975 (1988)). For optical CT, a solid phantom in which a physical light absorber such as ink is hardened with plastic has been proposed (SPIE Proc., Vol. 1888, pp.264-
270 (1993)).

[0004]

In the liquid phantom, the hemoglobin contained in the mixed solution is related to the absorption coefficient and the scatterer is related to the scattering coefficient. However, since the two cannot be separated, the absorption coefficient and the scattering coefficient are different. Cannot be adjusted independently. Therefore, in order to reset the phantom to one with different scattering / absorption conditions, it is necessary to make solutions with different mixing ratios from the beginning and inject them into the phantom, which is cumbersome to operate and has limited applications. I will be lost. Even in a solid phantom for optical CT, the scattering coefficient and the absorption coefficient cannot be adjusted independently, and it can be used for evaluation of position resolution of optical CT, but cannot be used for verification of oxygen saturation.

An object of the present invention is to provide a phantom in which the scattering condition and the absorbing condition can be accurately set independently of each other and which is easy to use. Another object of the present invention is to make it possible to freely change scattering conditions and absorption conditions during measurement.

[0006]

The phantom of the present invention comprises:
A large number of thin tubes are placed in a container that is filled or circulated with a transparent liquid or a light-scattering body solution, and the light-absorbing body liquid flows inside the tube, and the light-scattering body solution outside the tube and the light absorption inside the tube. It is equipped with a measurement unit that prevents body fluids from mixing with each other, and the concentration of the light-scattering body solution outside the tube can be independently varied. It is provided with a liquid feed pump for injecting and a light absorber liquid supply part for supplying a light absorber liquid.

In one embodiment, the light absorber liquid supply section is provided with a plurality of containers containing liquids having different light absorber concentrations and a concentration adjusting mechanism for mixing the liquids of the respective containers to obtain a predetermined concentration of the light absorber liquid. It is a thing.

In another aspect, a gas exchange section for varying the oxygen concentration of the light absorber liquid is further provided, and the gas exchange section is provided with a gas exchange tank and a large number of air-permeable tubes arranged therein. , The light absorber liquid flows inside or outside the breathable tube, and the mixed gas adjusted to a predetermined oxygen partial pressure outside or inside the breathable tube comes into contact with the light absorber liquid through the wall surface of the breathable tube. It is a thing.

[0009]

The concentration of the absorber (hematocrit) can be changed to an arbitrary value by the concentration adjusting mechanism of the light absorber liquid supply section. The oxygen exchange degree of the light absorber liquid flowing through the measurement section can be changed to an arbitrary value by the gas exchange section. In the measuring section, the scattering coefficient is set by the light scatterer solution or the light scatterer solution and a large number of tubes themselves. In this way, the absorption coefficient and the scattering coefficient that affect the light absorption of blood can be freely changed independently of each other, so that a more precise test or verification of the biometric device can be performed.

[0010]

Embodiment FIG. 1 schematically shows an embodiment. Along the flow path 4 provided with the liquid delivery pump 2, a light absorber liquid supply unit 6 for supplying a light absorber liquid having a variable concentration, a gas exchange unit 8 for adjusting the oxygen saturation of the light absorber, and a gas exchange unit are provided. The light absorber fluid that has passed through is flowed, and the detection unit 1 of the biometric device 14
A measuring unit 10 for performing the measurement according to 6 is arranged.
An example of the biometric device 14 is an oxygen monitor, and its probe is attached to the measurement unit 10 as the detection unit 16 to perform measurement. Reference numeral 12 is a temperature control unit, which keeps the temperature of the light absorber liquid at a constant temperature. The temperature control unit 12 is for preventing blood, which is a typical light absorber liquid, from being hemolyzed due to extremely low or high temperatures or rapid temperature changes. The position of the temperature control unit 12 is not limited to the position between the light absorber liquid supply unit 6 and the gas exchange unit 8. Further, when the entire measurement system is housed in the constant temperature bath, the temperature adjustment unit 12 is not necessary.

FIG. 2 shows the embodiment of FIG. 1 in detail. In FIG. 2, the light absorber liquid supply unit 6 includes a first liquid tank 6a containing physiological saline and a second liquid tank 6b containing blood or hemoglobin solution. A light-absorbing body liquid having a predetermined concentration is prepared and supplied by mixing and diluting with a saline solution at a predetermined ratio. The physiological saline in the first liquid tank 6a is supplied to the first liquid feed pump 2a via the first switching cock 20a.
And the second liquid tank 6b is connected to the second switching cock 20.
It is connected to the second liquid feed pump 2b via b. The downstream passages of the pumps 2a and 2b join the single passage 4. In the merged flow path 4, a temperature adjusting section 12, a gas exchange section 8 and a measuring section 10 are arranged along the flow direction of the light absorber liquid, and the flow path 4 is branched and switched downstream of the measuring section 10. It is connected to the cocks 20a and 20b. When the switching cock 20a is set to the flow path indicated by the solid line, the pump 2a is connected to the liquid tank 6a side, and the flow path downstream of the measuring unit 10 is connected to the drain tube 22a, so that the flow path is switched to the broken line. The flow path downstream of the measurement unit 10 is connected to the pump 2a, and the liquid tank 6a and the drain tube 22a are blocked from the flow path 4. When the switching cock 20b is set to the flow path of the solid line, the pump 2b is connected to the liquid tank 6b.
Side of the measuring part 10 is connected to the drain tube 22b, and when switched to the flow path of the broken line, the downstream part of the measuring part 10 is connected to the pump 2b and the liquid tank 6b. Flow path 4 through drain tube 22b
Shut off from.

By adjusting the flow rates of the pumps 2a and 2b in the light absorber liquid supply section 6, the light absorber concentration of the light absorber liquid supplied to the flow path 4 can be adjusted. For example, if hematocrit contains 50% of blood in the liquid tank 6b, the flow rate ratio between the pumps 2a and 2b is set to 1: 1 and the switching cocks 20a and 20b are set to the solid flow path, Blood of 25% hematocrit flows at the confluence point downstream of the pumps 2a and 2b.

The gas exchange section 8 comprises a gas exchange tank 30 and a bundle of thin tubes 32 passing through the gas exchange tank 30, and the gas exchange tank 30 has a gas inlet and a gas outlet. The N ₂ gas cylinder 34 a, the O ₂ gas cylinder 34 b, and the CO ₂ gas cylinder 34 c adjust the flow rate of each gas to supply a mixed gas set to a predetermined oxygen partial pressure to the gas suction port.
It is connected via a, 36b, and 36c. By adjusting the valves 36a to 36c, a mixed gas of nitrogen, oxygen and carbon dioxide can be mixed at an arbitrary partial pressure and supplied to the gas exchange tank 30. Gas exchange tank 30
A valve 38 for opening and closing is provided at the discharge port of.

The thin tube 32 used in the gas exchange section 8 is a thin tube made of a material such as silicone, and the wall surface of these tubes is porous so that liquid cannot pass but gas can pass. The light absorber liquid adjusted to a predetermined concentration from the light absorber liquid supply unit 6 enters the bundle of thin tubes 32 in the gas exchange tank 32 from the temperature adjustment unit 12. If the thin tube 32 is thin enough, gas exchange is facilitated. Since the component ratio of the gas in the gas exchange tank 30 can be arbitrarily changed, the gas exchange section 8 can produce a light absorber liquid having an arbitrary oxygen saturation.
When the light absorber fluid is, for example, a blood diluent, the oxygen saturation of blood hemoglobin is proportional to the oxygen partial pressure of the mixed gas in contact with the gas exchange unit 8. Therefore, the desired oxygen saturation should be obtained according to the oxygen divergence curve of blood hemoglobin. Gas exchange tank 3
Set an oxygen partial pressure of zero.

The measuring section 10 is a container in which a transparent liquid or a light-scattering body solution is filled or circulated, and a number of thin tubes are arranged in the container, and the light-absorbing body solution flows in the tubes. A specific example of the measuring unit 10 is shown in FIG. Measuring unit 1
0 is a large number of extremely thin tubes 4 of about 10,000 in the container 40
Two bundles are arranged, the bundle of tubes 42 is perfused with the light absorber liquid, and the scatterer solution is filled or circulated outside the tubes 42 in the container 40. Intralipid, milk, etc. are used as the scatterer solution. Since the tube 42 is extremely thin, the tube 42 itself also functions as a scatterer. Tube 4
The diameter of 2 is preferably about 0.2 mm.

The container 40 of the measuring section 10 is a transparent container,
The scatterer solution is provided with an inlet 44 and an outlet 46. The probe 16 of the oxygen monitor is brought into contact with the wall surface of the container 40 for measurement. The probe 16 includes a light-transmitting optical fiber 16a that guides light from a light source and a light-receiving optical fiber 16b that guides scattered light from the measurement unit 10 to the detection unit.

As the light absorber liquid for perfusing the inside of the tube 42 in the measuring section 10, in addition to a suspension containing red blood cells such as blood or its diluting liquid, a transparent liquid such as a hemoglobin solution or ink may be used. You can Blood or its diluted liquid is red blood cells (diameter 8 μm) containing hemoglobin hemoglobin.
Since it is a suspension because it contains disc-shaped particles (about m), a hemoglobin solution containing only hemoglobin is a transparent liquid even though it is absorbed.

Returning to the embodiment of FIG. 2, the operation will be described with reference to FIG. The switching cocks 20a and 20b are set to flow paths indicated by solid lines, and the concentration of blood or hemoglobin, which is a light-absorbing body fluid, is adjusted by the number of rotations of the pumps 2a and 2b (in FIG. 4). When the light absorber liquid reaches a certain concentration and becomes stable, the switching cocks 20a and 20b are switched to the flow paths indicated by the broken lines, and the flow path 4 is closed. This can reduce the amount of the light absorber liquid used.

Next, the valves 36a to 36 of the gas exchange section 8 will be described.
By adjusting c, the component ratio of the mixed gas to be supplied is adjusted (in FIG. 4), and when the component ratio of the mixed gas is equilibrated, all the valves 36a to 36c are closed. In that state, measurement is performed by the measuring unit 10. After that, when the valves 36a to 36c are adjusted again to change the oxygen saturation (in FIG. 4),
The ratio of oxyhemoglobin and deoxyhemoglobin can be changed without changing the blood volume. In the embodiment of FIG. 2, the gas exchange section 8 is made like an externally perfused artificial lung, blood passes through the gas exchange tank 30, and a breathable thin tube 32 is provided.
May have a structure through which the mixed gas passes.

FIG. 5 shows a second embodiment. Compared to the embodiment of FIG. 2, the switching mechanism for forming the closed flow path after the hematocrit is stabilized is different. That is,
In the light absorber liquid supply unit 6, the pumps 2a and 2b only supply physiological saline and blood or hemoglobin, respectively, and a pump 2c is newly provided as a liquid feed pump of the flow path 4. Further, the switching cocks 20c and 20d switch between an open flow path for discarding the light absorber liquid supply unit 6 through the flow path 4 to the drain and a closed flow path for the flow path 4. A gas exchange section 8 and a measurement section 10 are provided downstream of the pump 2c.
Is connected, and a bypass passage whose connection is switched by a switching cock 20e is connected to the passage 4 between the gas exchange unit 8 and the measuring unit 10, and the hematocrit (Hct) and the oxygen saturation ( A measuring device 50 for measuring SO ₂ ) is provided. The flow path downstream of the measuring unit 10 is switched by the switching cock 20d to form a circulation flow path returning to the pump 2c or to be connected to a flow path exhausted to the drain. The gas exchange unit 8 is connected to a mixed gas regulator 36 that regulates gas supply from the same gas cylinders 34a to 34c as in FIG. The mixed gas regulator 36 is the same as or equivalent to the valves 36a to 36c in FIG.

The operation of the embodiment of FIG. 5 is performed in the same manner as the embodiment of FIG. That is, the switching cocks 20c to 20e are set so that the light absorber liquid supplied from the light absorber liquid supply unit 6 is sent by the pump 2c and is discarded through the gas exchange unit 8, the measuring device 50 and the measuring unit 10. Then, the pumps 2a and 2b are adjusted to adjust the hematocrit, and when the measurement result of the measuring device 50 reaches a predetermined hematocrit, the switching cocks 20c and 20d are switched to form a closed flow path. To stop. Pump 2c
While the light absorber liquid in the closed channel is circulated by the measuring instrument 5
The mixed gas regulator 36 is adjusted so that the oxygen saturation at 0 becomes a predetermined value. After the hematocrit and the oxygen saturation have reached the predetermined values, the measuring unit 10 tests the biometric device.

FIG. 6 shows a case in which a plurality of measuring units 10 in the embodiment of FIG. 2 or 5 are prepared and these measuring units are incorporated in the measuring unit of the phantom for image measurement of optical CT.
As shown in (A), a bundle of thin tubes 4 in the measurement section
2a to 42c are housed in a container 52 filled with a light scatterer. Each of the tube bundles 42a to 42c is provided with the flow path of FIG. 2 or FIG. 3, and the respective hematocrit and the light absorber liquid adjusted to the oxygen saturation flow. By using such a measuring unit, a tomographic image as shown in FIG. 6B can be obtained.

FIG. 7 shows a third embodiment. In this embodiment, two measuring parts 10a and 10b are provided in the closed flow path 4 of the light absorber liquid.
Are connected in series. The measuring units 10a and 10b are shown in FIG.
It is the measuring unit shown in. The same light absorber liquid flows through both measuring sections 10a and 10b, but each tube 42
The outer light scatterers 43a and 43 surrounding the bundle of a and 42b.
For b, those having scattering coefficients different from each other are used. A light absorber liquid such as a hemoglobin solution or a blood diluent is stored in the reservoir 6c, and the light absorber liquid circulates in the flow path 4 by the pump 2d. In the flow path 4, a first measuring unit 10a is connected downstream of the gas exchange unit 8, a flow cell 60 is connected as a third measuring unit downstream thereof, and a second measuring unit 10b is connected downstream of the flow cell 60. Then, the outlet flow path of the measurement unit 10b returns to the reservoir 6c to form a circulation flow path. In the third measuring unit, the light source 60a and the detector 60b are arranged so as to face each other across the flow cell 60, and the transmittance of the light absorbing body fluid is measured in real time by the measurement light passing through the flow cell 60, and the absorbance thereof is measured. Therefore, the oxygen saturation and concentration of the light absorber liquid at that time can be accurately measured without being affected by scattering.

In the embodiment shown in FIG. 7, the first measuring section 10a and the second measuring section 10b are provided, and they are different only in the light scatterers 43a and 43b. It is possible to test whether or not the same absorption coefficient can be output even when the scattering conditions are different between when the first measurement unit 10a is set and when the second measurement unit 10b is set.

In the measuring units of the embodiments of FIGS. 1, 2, 3, 5, and 7 described above, the monitor of the biometric apparatus is a reflection type detector, but the measuring unit is sandwiched and light is irradiated. It goes without saying that the invention can also be applied to a transmission type probe in which the side fiber and the light receiving side fiber are arranged to face each other.

FIG. 8 shows a fourth embodiment. The embodiment of FIG. 7 is aimed at calibrating a device for measuring absorption at a specific point such as an oxygen monitor, whereas the embodiment of FIG. 8A measures a spatial distribution such as optical CT. The purpose is to verify the device. The measuring unit 70 is a transparent plastic container filled with a milky scatterer liquid 72, and a
The thin tube bundle 42a of the second measuring section and the thin tube bundle 42b of the second measuring section are arranged. The bundles 42a and 42b of both tubes are connected in series, and the
A light absorber liquid such as a hemoglobin solution or a blood diluent stored in c is sent by the pump 2d and adjusted to a predetermined oxygen saturation level in the gas exchange unit 8, and then the bundle of tubes 42a of the first measurement unit is used. Then, the reservoir 6c returns from the second measuring section through the tube bundle 42b and the third measuring section, ie, the flow cell 60.

In the verification of optical CT, the plastic container 70
A large number of light sources 74 and detectors 76 are arranged on the outer circumference of, to reconstruct a sectional image. FIG. 8 (B) is a cross-sectional image expected in that case, and shows whether or not an image of the size of the bundles 42a and 42b of the tube of the measuring unit, the concentration of the light absorber liquid, and the darkness corresponding to the oxygen state can be obtained. Verify. The structure other than the measuring part is the same as that shown in FIG. Although not shown in FIGS. 7 and 8, these phantoms are usually used together with a temperature control device.

[0028]

According to the present invention, since the light-absorbing body liquid flows without mixing the light-absorbing body liquid and the light-scattering body liquid in the measuring section, the light-absorption coefficient and the scattering coefficient can be adjusted independently. The coefficient can be changed freely and both can be set accurately, and it becomes an easy-to-use phantom. The absorption coefficient can be adjusted by the concentration of the light absorber liquid flowing through the tube, and the scattering coefficient can be adjusted by the scatterer concentration of the scatterer liquid. And since both are not mixed, they can be adjusted independently,
You can also put it back. Since the interaction between the scatterer liquid and the light absorber liquid in the tube can be prevented, the light absorber liquid is not adsorbed to the scatterer liquid to cause a problem. Blood that is not a transparent body may be perfused into the tube. In this case, perfusion with a solution diluted with physiological saline is performed.
The absorption coefficient can be made variable by adjusting the dilution rate.

Since the ultrafine tube itself in the measuring section is a scatterer, the tube portion can be regarded as a scatterer even if the liquid flowing in the tube is a transparent solution, for example, a pure hemoglobin solution. Almost uniform scattering and can be regarded as an absorber. Filling or flushing the scatterer liquid into the container outside the tube allows the scattering coefficient to be increased or varied freely. Since the light absorber fluid flowing in the tube and the scatterer fluid on the outside are separated, any type of scatterer fluid can be used, and the degree of freedom in adjusting the scattering coefficient of the tissue is increased. On the other hand, in the mixing method using the liquid phantom, once mixed and the optical constants (scattering coefficient and absorption coefficient) are determined, it is not possible to change to another combination of optical coefficients.

In the present invention, the light absorber concentration of the light absorber liquid sent to the measuring unit can be changed by the light absorber liquid supply unit, and the oxygen saturation of the light absorber liquid can be freely adjusted by the gas exchange unit. be able to. In this way, by varying the concentration or oxygen saturation of the blood perfused into the tube, it is possible to freely adjust the amount that simulates the two parameters of blood volume and oxygen saturation.

[Brief description of drawings]

FIG. 1 is a block diagram schematically showing an embodiment.

FIG. 2 is a configuration diagram showing the same embodiment.

FIG. 3 is a cross-sectional view showing in detail a measuring unit used in the same example.

FIG. 4 is a time chart showing the operation of the embodiment.

FIG. 5 is a configuration diagram showing a second embodiment.

6A and 6B are diagrams showing an example of another measuring unit, FIG. 6A is a schematic perspective view, and FIG. 6B is a diagram showing a tomographic image to be measured.

FIG. 7 is a configuration diagram showing a third embodiment.

FIG. 8 is a diagram showing a fourth embodiment, (A) is a schematic configuration diagram, and (B) is a diagram showing a tomographic image to be obtained.

[Explanation of symbols]

 2, 2a to 2d Pump 4 Flow path 6 Light absorber liquid supply part 8 Gas exchange part 10, 10a, 10b Measuring part 14 Oxygen monitor 16 Oxygen monitor probe 42, 42a, 42b, 42c Thin tube

Claims (3)

[Claims] 1. At least a light absorption body liquid supply unit for supplying a light absorption body liquid and a measurement unit for performing measurement by a detection unit of a biometric apparatus are provided along a flow path provided with a liquid supply pump, and the measurement unit is provided. Is a container filled with or circulated with a transparent liquid or a light-scattering solution, and a number of thin tubes are placed in the tube.The light-absorbing solution flows inside the tube, and the light-scattering solution outside the tube and the light inside the tube A phantom for certifying a biometric device, characterized in that it does not mix with the absorbent fluid. 2. The light absorber liquid supply section comprises a plurality of containers for containing liquids having different light absorber concentrations, and a concentration adjusting mechanism for mixing the liquids of the respective containers to obtain a predetermined concentration of the light absorber liquid. The phantom for biometric device verification according to claim 1. 3. A gas exchange section for adjusting the oxygen saturation of the light absorber liquid supplied to the measurement section is further provided along a flow path provided with a liquid feed pump, and the gas exchange section is a gas exchange tank. With a number of breathable tubes disposed therein, the light absorber fluid flowing inside or outside the breathable tubes,
The phantom for assaying a biometric device according to claim 1, wherein the mixed gas adjusted to have a predetermined oxygen partial pressure on the outside or inside of the breathable tube comes into contact with the light absorber fluid through the wall surface of the breathable tube.