Patent Description:
A urine sample contains particles such as red blood cells, white blood cells, epithelial cells, and urinary casts, and observing these particles in the urine sample is effective in diagnosing diseases of the kidney and the urinary tract. The prior art documents below each disclose a device for imaging particles contained in a biological sample such as a urine sample.

In a test for a liquid biological sample such as a urine sample, adopting a structure, in which the biological sample is supplied from a container to an imaging cell (imaging range) through a liquid flow channel such as a tube or a pipe, is advantageous for automation of the test. In the process of investigating this structure, the inventors of the present invention have obtained the findings below.

That is, when the biological sample is caused to flow through the liquid flow channel as described above, an axial concentration effect acts on the particles in the biological sample. That is, according to fluid dynamics, the flow rate of the biological sample increases as the biological sample approaches the center axis of the liquid flow channel, and the particles in the biological sample gather around the center axis of the liquid flow channel, where the flow rate is highest. This axial concentration effect greatly acts on large-sized particles. As a result, the large-sized particles are flowed at a high flow rate to the downstream side, and the density of the large-sized particles increases near a downstream end of the biological sample (at the head of the biological sample) flowing through the liquid flow channel.

In a urine sample, generally, large-sized particles such as epithelial cells and urinary casts are low in density, but the density of these particles can be increased in a downstream end portion of the biological sample by using the aforementioned axial concentration effect. By increasing the density of the particles, the particles can be efficiently reflected in images. Meanwhile, in image-taking with a camera, an imaging range has a two-dimensional expansion to some extent. However, if a particle imaging range is set in the downstream end portion of the biological sample, large-sized particles are concentrated and overlap each other in a downstream end portion of the imaging range, which makes it difficult to reflect the individual particles in images. Furthermore, if the imaging range is set on the upstream side of the downstream end portion of the biological sample so as to be apart from the downstream end portion, there is a possibility that a sufficient number of large-sized particles are not present within the imaging range. In this case, a sufficient number of large-sized particles cannot be reflected in images.

Therefore, an object of the present invention is to provide a biological sample imaging device and a biological sample imaging method that are capable of disposing a sufficient number of large-sized particles in a biological sample so as to be moderately dispersed within an imaging range.

A biological sample imaging device according to one aspect of the present invention is defined in claim <NUM>.

A biological sample imaging method according to a further aspect of the invention is defined in claim <NUM>.

According to the present invention, it is possible to realize a biological sample imaging device and a biological sample imaging method that are capable of disposing a sufficient number of large-sized particles in a biological sample so as to be moderately dispersed within an imaging range.

<FIG> is a configuration diagram showing a biological sample imaging device according to an embodiment of the present invention. The biological sample imaging device <NUM> shown in <FIG> is an apparatus for taking images of particles in a liquid biological sample containing the particles. In this embodiment, a urine sample is used as an example of the biological sample, and images of particles such as red blood cells, white blood cells, epithelial cells, and urinary casts in the urine sample are taken by the biological sample imaging device <NUM>. Examples of the epithelial cells include squamous cells, transitional cells, and tubular epithelial cells. Examples of the urinary casts include hyaline casts, epithelial casts, red blood cell casts, white blood cell casts, fatty casts, granular casts, and waxy casts.

The biological sample is not limited to urine, and may be blood, coelomic fluid, or the like. The biological sample may be a liquid directly collected from an organism, or may be a sample obtained by diluting the liquid with another liquid. Alternatively, the biological sample may be a sample obtained by dissolving particles collected from an organism into a liquid.

Of the particles contained in the urine sample, particles such as red blood cells and white blood cells, each having a particle size of about <NUM>, are referred to as small particles in the present embodiment. Meanwhile, particles such as epithelial cells and urinary casts, each having a particle size of about <NUM> to <NUM>, are referred to as large particles in the present embodiment.

As shown in <FIG>, the biological sample imaging device <NUM> according to the present embodiment includes a liquid flow channel <NUM>, a light source <NUM>, an objective lens <NUM>, a camera <NUM>, a data processing unit <NUM>, a display unit <NUM>, a syringe pump <NUM>, a washing liquid container <NUM>, a suction nozzle actuator <NUM>, a washing chamber <NUM>, and a waste liquid container <NUM>. The liquid flow channel <NUM> includes a rod-shaped hollow suction nozzle <NUM>, a liquid flow channel inside a second sensor 28b, a liquid flow channel inside a first sensor 28a, and an imaging cell <NUM> arranged in order from the upstream side. The liquid flow channel <NUM> further includes tubes <NUM>, such as silicon tubes, connected to these components. The imaging cell <NUM> is formed from a translucent material into a plate shape. The imaging cell <NUM> has an inner space formed in a flat rectangular-parallelepiped shape, through which the urine sample flows. Thus, the imaging cell <NUM> allows observation of the urine sample held in the inner space from the outside. An upstream end of the liquid flow channel <NUM> is a tip of the suction nozzle <NUM>, and a downstream end thereof is a suction/discharge port of the syringe pump <NUM>. An inner space of the liquid flow channel <NUM> has a circular cross section, except a portion inside the imaging cell <NUM>. On the liquid flow channel <NUM>, a first position A is set on the upstream side of the imaging cell <NUM>, and a second position B is set on the upstream side of the first position A. The first position A and the second position B will be described later in detail.

The light source <NUM> includes a convex lens and a light emitting element such as an LED. The light source <NUM> is disposed directly below the imaging cell <NUM>. Light emitted from the light emitting element is converted to parallel light by the convex lens, and the parallel light enters the imaging cell <NUM> made of a translucent material, from a lower portion of the imaging cell <NUM>. The camera <NUM> is a CCD image sensor or a CMOS image sensor. The camera <NUM> is disposed directly above the imaging cell <NUM> together with the objective lens <NUM>. The objective lens <NUM> and the camera <NUM> constitute a microscope camera. The microscope camera generates image data of the urine sample filled in the imaging cell <NUM>. The display unit <NUM> is a display panel such as an LCD or an OLED. The display unit <NUM> displays information such as the image data generated by the camera <NUM>.

The data processing unit <NUM> is a computer system composed of a CPU and a memory as main components, and the camera <NUM> and the display unit <NUM> are connected to the data processing unit <NUM>. Furthermore, although not illustrated in <FIG>, the following components are also connected to the data processing unit <NUM>: the light source <NUM>; a piston actuator 24a of the syringe pump <NUM>; a solenoid valve provided in the tube between the syringe pump <NUM> and the washing liquid container <NUM>; the first sensor 28a; the second sensor 28b; the suction nozzle actuator <NUM>; and a solenoid valve provided in a drain tube of the washing chamber <NUM>. An image analysis program and various control programs are installed on the data processing unit <NUM>. The data processing unit <NUM> causes the display unit <NUM> to display the image data generated by the camera <NUM>. In addition, the data processing unit <NUM> analyzes the image data generated by the camera <NUM>, and detects particles reflected in the image data. Moreover, the data processing unit <NUM> controls the piston actuator 24a, the suction nozzle actuator <NUM>, and the respective solenoid valves. Of the various functions to be implemented by the data processing unit <NUM>, part or all of them may be implemented by another type of hardware such as ASIC or FPGA.

The syringe pump <NUM> generates a negative pressure or a positive pressure with respect to the liquid flow channel <NUM> to cause a liquid or a gas to flow through the liquid flow channel <NUM> in a forward direction from the upstream end toward the downstream end or in a direction reverse to the forward direction. Specifically, the syringe pump <NUM> sucks the urine sample from a sample container <NUM> such as a test tube, and fills the inner space of the imaging cell <NUM> with the urine sample. Further, the syringe pump <NUM> causes a liquid or a gas in the liquid flow channel <NUM> to flow reversely. The syringe pump <NUM> includes a cylinder and a piston that is inserted in the cylinder, and the piston actuator 24a is mounted to the piston. In accordance with a command from the data processing unit <NUM>, the piston actuator 24a, which is an electric drive means such as a motor, pulls out the piston from the cylinder (forward actuation), or pushes the piston into the cylinder (reverse actuation). An opening is provided at a side surface of the cylinder. A tube, which connects the inside of the washing liquid container <NUM> to the inside of the syringe pump <NUM>, is connected to the opening. When the piston is pulled out from the cylinder and thereby the inner space between the piston and the cylinder comes to have a predetermined capacity or more, the inside of the washing liquid container <NUM> becomes communicable with the inside of the syringe pump <NUM>.

The suction nozzle actuator <NUM> causes the suction nozzle <NUM> to move in the up-down and left-right directions in accordance with a command from the data processing unit <NUM>. Specifically, a plurality of sample containers <NUM> held in a rack are transported, by a transporting means such as a belt conveyor, to a suction position of the biological sample imaging device <NUM>. The suction nozzle actuator <NUM> inserts the suction nozzle <NUM> in one of the sample containers <NUM> sequentially selected by the data processing unit <NUM>, and pulls out the suction nozzle <NUM> from the sample container <NUM>. When the suction nozzle <NUM> or the liquid flow channel <NUM> is washed, the suction nozzle actuator <NUM> inserts the suction nozzle <NUM> in the washing chamber <NUM>.

Each of the first sensor 28a and the second sensor 28b outputs data according to the type of an object (liquid or gas) that flows through a sensor position in the liquid flow channel <NUM>. For example, a conductivity sensor may be used as the first sensor 28a and the second sensor 28b. The conductivity sensor is provided so as to come into contact with the biological sample that passes through the liquid flow channel <NUM>. For example, the conductivity sensor includes two tubular electrodes separately disposed on the upstream side and the downstream side. The conductivity sensor outputs the conductivity of the object that flows between the electrodes. Instead of the conductivity sensor, an optical sensor may be used as the first sensor 28a and the second sensor 28b. The optical sensor includes a light emitter and a light receiver arranged opposed to each other via a tube in which the biological sample flows. An object that flows in the tube is irradiated with light emitted from the light emitter, and a signal reflecting the intensity of the light that has transmitted through the object is outputted from the light receiver.

A description is now given of how particles in the biological sample behave when the biological sample flows in the liquid flow channel <NUM>. <FIG> schematically shows the inside of a tube <NUM> during the forward actuation of the syringe pump <NUM>.

As described later in detail, the liquid flow channel <NUM> such as the tube <NUM> is filled with a washing liquid <NUM> in the initial state. When a biological sample <NUM> is filled in the imaging cell <NUM>, firstly, a small amount of air <NUM> is sucked, and thereafter, a predetermined amount of the biological sample <NUM> is sucked from the sample container <NUM>. Therefore, as shown in <FIG>, the air <NUM> (air gap) is positioned on the upstream side of the washing liquid <NUM>, and the biological sample <NUM> is positioned on the upstream side of the air <NUM>.

As already described above, in the liquid flow channel <NUM> such as the tube <NUM>, the flow rate of the biological sample increases as the biological sample approaches the center axis of the liquid flow channel <NUM>. Then, the particles in the biological sample gather around the center axis of the liquid flow channel <NUM>, where the flow rate is highest. This axial concentration effect greatly acts on large particles such as epithelial cells <NUM> and urinary casts <NUM>. As a result, the epithelial cells <NUM> and the urinary casts <NUM> are carried to the downstream side at a high flow rate. Thus, as shown in <FIG>, the density of the epithelial cells <NUM> and the urinary casts <NUM> is increased around a downstream end 104a of the biological sample <NUM> which flows through the liquid flow channel <NUM>. Since red blood cells <NUM> and white blood cells <NUM> have sufficiently small particle sizes with respect to the flow-rate profile of the liquid flow channel <NUM>, the axial concentration effect can be ignored.

<FIG> is a distribution chart of large particles and small particles in the biological sample <NUM> immediately after the syringe pump <NUM> is forwardly actuated. The vertical axis indicates a value obtained by dividing the particle density (number of particles per unit volume) in the liquid flow channel <NUM> by the particle density in the sample container <NUM>. The horizontal axis indicates the volume from the downstream end 104a of the biological sample <NUM>. As shown in <FIG>, in the direction from the upstream end to the downstream end of the biological sample <NUM> (in the direction to the right in <FIG>), the particle density of the large particles such as the epithelial cells <NUM> and the urinary casts <NUM> increases. That is, the particle density ratio of the large particles reaches about <NUM>% near the downstream end 104a of the biological sample <NUM>. That is, by causing the biological sample <NUM> to flow through the liquid flow channel <NUM>, the effect of condensing the large particles can be obtained. Therefore, by taking images of an area around the downstream end 104a of the biological sample <NUM> after the biological sample <NUM> is caused to flow through the liquid flow channel <NUM>, images of the large particles such as the epithelial cells <NUM> and the urinary casts <NUM> can be efficiently taken.

Unlike the large particles, the particle density ratio of the small particles such as the red blood cells <NUM> and the white blood cells <NUM> decreases in the direction from the upstream end to the downstream end of the biological sample <NUM>. The particle density ratio of the small particles is less than <NUM>% at any position. The reason of this is considered as follows. That is, as described above, the axial concentration effect hardly acts on the small particles. In addition, the biological sample <NUM> is diluted toward the downstream side by the washing liquid <NUM> attached to an inner wall surface of the liquid flow channel <NUM>.

As described above, when the biological sample <NUM> is caused to flow through the liquid flow channel <NUM>, the density of the large particles such as the epithelial cells <NUM> and the urinary casts <NUM> can be increased near the downstream end 104a of the biological sample <NUM>. Increasing the density of the particles allows the particles to be efficiently reflected in images. However, as described later in detail, the imaging cell <NUM> has an inner space that expands in the horizontal direction, and the entirety or a part of the inner space is set as an imaging range for the camera <NUM>. If the downstream end 104a of the biological sample <NUM> is located within the imaging range, the large particles are concentrated in a part of the imaging range, and are overlapped with each other in the vertical direction, which makes it difficult to reflect the individual particles in images. On the other hand, if a portion, of the biological sample <NUM>, a predetermined distance apart from the downstream end 104a is located within the imaging range, there is a possibility that a sufficient number of large particles are not present in such a portion. In this case, a sufficient number of large particles cannot be reflected in images.

Therefore, in the present embodiment, a pump control is executed, by which the large particles concentrated around the downstream end 104a of the biological sample <NUM> is dispersed again. That is, in the present embodiment, forward actuation of the syringe pump <NUM> is temporarily stopped immediately before the biological sample <NUM> enters the inner space of the imaging cell <NUM>. Specifically, when the downstream end 104a of the biological sample <NUM> has reached the first position A (refer to <FIG>) that is set on the upstream side of the imaging cell <NUM>, the operation of the syringe pump <NUM> is stopped. Then, the syringe pump <NUM> is reversely actuated until the downstream end 104a of the biological sample <NUM> reaches the second position B. The second position B is set on the upstream side relative to the first position A. That is, the biological sample <NUM> is pushed back to the upstream side.

<FIG> schematically shows the inside of the liquid flow channel <NUM> during the reverse actuation of the syringe pump <NUM>. When the syringe pump <NUM> is reversely actuated, the biological sample <NUM> moves to the upstream side, that is, toward the suction nozzle <NUM>. Also in this case, the axial concentration effect greatly acts on the large particles such as the epithelial cells <NUM> and the urinary casts <NUM>. Therefore, the large particles concentrated around the downstream end 104a move in the upstream direction relative to the small particles, as shown in <FIG>. Thus, by reversely actuating the syringe pump <NUM> only by a predetermined volume, the large particles concentrated around the downstream end 104a can be favorably dispersed to a portion apart from the downstream end 104a.

When the downstream end 104a of the biological sample <NUM> has reached the second position B, the syringe pump <NUM> is temporarily stopped, and then the syringe pump <NUM> is forwardly actuated until the downstream end 104a of the biological sample <NUM> reaches a third position C. The third position C is set on the downstream side of the imaging cell <NUM> in the liquid flow channel <NUM>. Thus, the inner space of the imaging cell <NUM> can be filled with the biological sample <NUM>.

A description is now given of the imaging cell <NUM>. <FIG> is a perspective view of the imaging cell <NUM>. As shown in <FIG>, the imaging cell <NUM> includes: an inner space 14e for holding a urine sample; and an inflow path 14f and an outflow path <NUM>, through which the inner space 14e communicates with the outside. The imaging cell <NUM> has a rectangular parallelepiped outer shape that is flat and extends in one direction. The inner space 14e also has a rectangular parallelepiped shape that is flat and extends in one direction. The inner space 14e is arranged along the outer shape of the imaging cell <NUM>. The imaging cell <NUM> is placed so that the bottom surface of the inner space 14e becomes horizontal.

The inner space 14e is sandwiched, in the vertical direction, by a thin plate part 14a and a thin plate part 14b which are parallel and opposed to each other. At least the thin plate part 14a and the thin plate part 14b of the imaging cell <NUM> are formed from a translucent material such as glass or resin.

The inner space 14e has a rectangular parallelepiped shape that extends in one direction as described above, and the surface at one end thereof in the longitudinal direction is an upstream end 14c while the surface at the other end thereof in the longitudinal direction is a downstream end 14d. The inflow path 14f communicating with an opening at a side surface of the imaging cell <NUM> is formed in a portion, of a side wall of the imaging cell <NUM>, right next to the upstream end 14c of the inner space 14e. Likewise, the outflow path <NUM> communicating with an opening at the side surface of the imaging cell <NUM> is formed in a portion, of the side wall of the imaging cell <NUM>, right next to the downstream end 14d of the inner space 14e. A tube <NUM> communicating with the first sensor 28a is connected to the inflow path 14f, and a tube <NUM> communicating with the syringe pump <NUM> is connected to the outflow path <NUM>.

The light source <NUM> is disposed below the imaging cell <NUM>, and parallel light enters the imaging cell <NUM> from the thin plate part 14b side. The microscope camera composed of the objective lens <NUM> and the camera <NUM> is disposed above the imaging cell <NUM>. The microscope camera takes an image of the urine sample filled in the inner space 14e, through the thin plate part 14a. Although it is preferable that the imaging range (range utilized for display and/or image analysis) of the microscope camera is the entirety of the rectangular parallelepiped inner space 14e, the imaging range may be a part of the inner space 14e.

<FIG> schematically shows a cross section of the imaging cell <NUM> immediately after the imaging cell <NUM> has been filled with the biological sample <NUM>. <FIG> schematically shows a cross section of the imaging cell <NUM> after a predetermined time period has passed from the filling with the biological sample <NUM>. As shown in <FIG>, immediately after the imaging cell <NUM> has been filled with the biological sample <NUM>, the particles are floating in the space between the thin plate part 14a and the thin plate part 14b. However, after the predetermined time period has passed, the particles are precipitated at the bottom as shown in <FIG>. The microscope camera composed of the objective lens <NUM> and the camera <NUM> is focused on the vicinity of the surfaces of the particles precipitated at the bottom, and takes a macrophotograph. According to the present embodiment, a sufficient number of large particles are present between the thin plate part 14a and the thin plate part 14b, and moreover, the large particles are favorably dispersed. Therefore, even when the large particles are precipitated at the bottom, the large particles hardly overlap each other in the vertical direction. As a result, images of the individual large particles can be clearly taken.

Although the width of the inner space 14e is sufficiently large, the height of the inner space 14e, i.e., the interval between the thin plate part 14a and the thin plate part 14b, is smaller than the dimension of any part of the liquid flow channel <NUM>, except the imaging cell <NUM>. In particular, the height of the inner space 14e is smaller than the inner diameters of the suction nozzle <NUM> and the tube <NUM> provided on the upstream side relative to the imaging cell <NUM>. By adopting this configuration, the particles in the inner space 14e can be quickly precipitated to be ready for image-taking.

<FIG> is a functional block diagram showing the data processing unit <NUM>. As described above, the data processing unit <NUM> is configured by a computer system, and implements various functions by executing programs. As shown in <FIG>, the data processing unit <NUM> functionally includes a first determination unit 20a, a second determination unit 20b, a pump controller 20c, an imaging controller 20d, an abnormality determination unit 20e, a suction nozzle controller 20f, and an agitation controller <NUM>.

The first determination unit 20a determines that the downstream end 104a of the biological sample <NUM> has reached the first position A provided on the liquid flow channel <NUM>. For example, the first determination unit 20a may determine that the downstream end 104a of the biological sample <NUM> has reached the first position A, on the basis of the suction amount or the discharge amount of the syringe pump <NUM>. The suction amount or the discharge amount of the syringe pump <NUM> can be determined based on the operation amount of the piston actuator 24a. In addition, the cross-sectional area of the liquid flow channel <NUM> is already known, and the internal capacity of the liquid flow channel <NUM> from the upstream end to the first position A is also already known. Accordingly, when the suction amount of the syringe pump <NUM> has reached the known internal capacity, the first determination unit 20a can determine that the downstream end 104a of the biological sample <NUM> has reached the first position A provided on the liquid flow channel <NUM>.

The first determination unit 20a may determine that the downstream end 104a of the biological sample <NUM> has reached the first position A, on the basis of an output from a sensor provided in the liquid flow channel <NUM>. For example, a conductivity sensor may be disposed at the first position A, and the first determination unit 20a may determine that the downstream end 104a of the biological sample <NUM> has reached the first position A, on the basis of the conductivity outputted from the conductivity sensor. According to the present embodiment, since the air <NUM> is caused to be adjacent to the downstream side of the biological sample <NUM>, when the conductivity of the biological sample <NUM> is detected while the conductivity of the air <NUM> is being detected, this timing allows the determination that the downstream end 104a of the biological sample <NUM> has reached the position of the conductivity sensor, i.e., the first position A.

Alternatively, the first determination unit 20a may determine that the downstream end 104a of the biological sample <NUM> has reached the first position A, on the basis of both an output from the sensor and the suction amount/discharge amount of the syringe pump <NUM>. For example, the first sensor 28a is mounted on the upstream side relative to the first position A, and the internal capacity of the liquid flow channel <NUM> from the detection position of the first sensor 28a to the first position A is already known. Therefore, when the suction amount of the syringe pump <NUM> reaches the known internal capacity after the timing when the first sensor 28a determines that the downstream end 104a of the biological sample <NUM> has reached the detection position of the first sensor 28a, the first determination unit 20a can determine that the downstream end 104a of the biological sample <NUM> has reached the first position A.

The second determination unit 20b determines that the downstream end 104a of the biological sample <NUM> has reached the second position B provided on the liquid flow channel <NUM>. This determination can be performed similarly to the determination by the first determination unit 20a. For example, the internal capacity of the liquid flow channel <NUM> from the first position A to the second position B is already known. Therefore, the syringe pump <NUM> is reversely actuated from the state where the downstream end 104a of the biological sample <NUM> is located at the first position A, then if the discharge amount thereof reaches the known internal capacity, it can be determined that the downstream end 104a has reached the second position B.

Alternatively, the second determination unit 20b may determine that the downstream end 104a of the biological sample <NUM> has reached the second position B, on the basis of an output from a sensor provided in the liquid flow channel <NUM>. For example, a conductivity sensor may be disposed at the second position B, and the second determination unit 20b may determine that the downstream end 104a of the biological sample <NUM> has reached the second position B, on the basis of the conductivity outputted from the conductivity sensor. According to the present embodiment, since the air <NUM> is caused to be adjacent to the downstream side of the biological sample <NUM>, when the conductivity of the air <NUM> is detected while the conductivity of the biological sample <NUM> is being detected, this timing allows the determination that the downstream end 104a of the biological sample <NUM> has reached the position of the conductivity sensor, i.e., the second position B.

The pump controller 20c instructs the operation of the piston actuator 24a. In particular, when the biological sample <NUM> is filled in the imaging cell <NUM>, the pump controller 20c causes the syringe pump <NUM> to sequentially perform: a first operation (forward actuation) in which the biological sample <NUM>, having been introduced into the liquid flow channel <NUM>, is caused to flow in the forward direction, and the downstream end 104a thereof is caused to reach the first position A; and a second operation (reverse operation) in which the biological sample <NUM> is caused to flow in the reverse direction, and the downstream end 104a thereof is caused to reach the second position B. The first operation includes: a liquid introducing operation of introducing a predetermined amount of the biological sample <NUM> from the tip of the suction nozzle <NUM> into the liquid flow channel <NUM>; and an air introducing operation of, after the liquid introducing operation, pulling up the suction nozzle <NUM> from the sample container <NUM>, and introducing air from the tip of the suction nozzle <NUM> into the liquid flow channel <NUM>. Thus, by causing air to flow through the upstream side of the biological sample <NUM>, the amount of the biological sample <NUM> required for image-taking can be reduced. After the second operation, the pump controller 20c causes the piston actuator 24a to perform a third operation of causing the biological sample <NUM> to flow in the forward direction again. Thus, the downstream end 104a of the biological sample <NUM> is caused to reach the third position C. The third position C may be set at the downstream end 14d of the inner space 14e of the imaging cell <NUM>, or at any position that is near the imaging cell <NUM> and on the downstream side relative to the downstream end 14d. The third operation is performed with the tip of the suction nozzle <NUM> being pulled up from the liquid surface in the sample container <NUM>.

If the third position C is set on the downstream side relative to the inner space 14e of the imaging cell <NUM>, the downstream end 104a of the biological sample <NUM> can be prevented from entering the imaging range. There is a possibility that the washing liquid <NUM> or the like attached to the inner wall of the liquid flow channel <NUM> is mixed into a portion around the downstream end 104a of the biological sample <NUM>. If the third position C is set on the downstream side relative to the inner space 14e of the imaging cell <NUM>, image-taking of the biological sample <NUM> can be performed while avoiding such a portion.

Since the aforementioned second operation is performed in the present embodiment, the large particles concentrated around the downstream end 104a of the biological sample <NUM> due to the first operation are pushed back to the upstream side, whereby a sufficient number of large particles can be ensured within the imaging range. Further, the second operation allows the large particles to be favorably dispersed within the imaging range.

The first position A is set on the upstream side relative to the inner space 14e of the imaging cell <NUM>, which is the imaging range. Thus, the large particles can be dispersed in the liquid flow channel <NUM> at the upstream side of the imaging cell <NUM>, and thereafter, the biological sample <NUM> can be filled in the imaging cell <NUM>. Therefore, the large particles such as the epithelial cells <NUM> and the urinary casts <NUM> can be prevented from clogging the imaging cell <NUM>. That is, since the height of the inner space 14e of the imaging cell <NUM> is very low as mentioned above, clogging of the large particles is a concern. However, according to the present embodiment, such clogging can be prevented.

The internal capacity from the second position B to the tip of the suction nozzle <NUM> is desired to be greater than the internal capacity of the liquid flow channel <NUM> at least within the imaging range (the internal capacity of the inner space 14e of the imaging cell <NUM>). Otherwise, the already sucked biological sample <NUM> is discharged from the tip of the suction nozzle <NUM> due to the second operation.

The internal capacity of the liquid flow channel <NUM> from the second position B to the upstream end 14c of the imaging cell <NUM> is desired to be not greater than <NUM> times the internal capacity of the liquid flow channel <NUM> within the imaging range, that is, the internal capacity of the inner space 14e of the imaging cell <NUM>. Thus, the movement amount of the biological sample <NUM> during the third operation can be reduced, thereby preventing the large particles from being again concentrated around the downstream end 104a of the biological sample <NUM> due to the third operation.

The second operation is performed with the tip of the suction nozzle <NUM> being pulled up from the liquid surface in the sample container <NUM>. Thus, air is prevented from being supplied into the sample container <NUM>.

The internal capacity of the liquid flow channel <NUM> from the first position A to the second position B is desired to be not greater than one-tenth of the internal capacity from the tip of the suction nozzle <NUM> to the first position A. When the extent of pushing back the large particles in the reverse direction is relatively reduced, the particle condensing effect due to the axial concentration effect is maintained, whereby a sufficient number of large particles can be ensured within the imaging range.

When the operation of the syringe pump <NUM> is stopped after the third operation by the pump controller 20c, the imaging controller 20d waits for elapse of a predetermined time period required for precipitation of the particles, and then causes the camera <NUM> to take images of the particles in the biological sample <NUM> within the imaging range, that is, within the inner space 14e of the imaging cell <NUM>. Thus, the images taken of the biological sample <NUM> are displayed on the display unit <NUM>, or used for image analysis.

The imaging controller 20d takes images of the biological sample <NUM> for each of the plurality of sample containers <NUM> held in the rack. At this time, the pump controller 20c performs the aforementioned first to third operations for each biological sample <NUM>.

The abnormality determination unit 20e detects an abnormality that the amount of the biological sample <NUM> sucked from the sample container <NUM> is less than a specified amount, when the biological sample <NUM> is supplied into the imaging cell <NUM>. Specifically, a shortage monitoring period is provided after start of the air introduction in the first operation, and if air is detected by the second sensor 28b during the shortage monitoring period, it is determined that the biological sample <NUM> is insufficient. The shortage monitoring period is a period during which a specified amount of the biological sample <NUM> should pass through the detection position of the second sensor 28b. When such an abnormality is detected, the abnormality is displayed on the display unit <NUM>, for example. The abnormality determination unit 20e can improve the reliability of the images of the biological sample <NUM>. The suction nozzle controller 20f instructs the operation of the suction nozzle actuator <NUM>.

Before the first operation by the pump controller 20c, the agitation controller <NUM> causes the biological sample <NUM> in the sample container <NUM> to be agitated. For example, an agitation nozzle (not shown) is inserted in the sample container <NUM>, and a certain amount of the biological sample <NUM> is sucked by using an agitation pump (not shown), and thereafter, the sucked biological sample <NUM> is returned to the sample container <NUM> by the agitation pump, thereby agitating the biological sample <NUM> in the sample container <NUM>. Alternatively, the biological sample <NUM> in the sample container <NUM> may be agitated by discharging air from the agitation nozzle. The biological sample <NUM> may be agitated by using the syringe pump <NUM> and the suction nozzle <NUM> in the same manner as described above. In the present embodiment, an exemplary structure is adopted in which an agitation nozzle (not shown) is formed integrally with the suction nozzle <NUM>, and the biological sample <NUM> in the sample container <NUM> is agitated by using an agitation pump (not shown) different from the syringe pump <NUM>. The integrated agitation nozzle and suction nozzle <NUM> can be actuated together by the suction nozzle actuator <NUM>.

Hereinafter, the operation of the biological sample imaging device <NUM> is described in a time series manner. <FIG> shows, in a time series manner, how the biological sample <NUM> flows through the liquid flow channel <NUM>. <FIG> and <FIG> are flowcharts showing the operation of the biological sample imaging device <NUM>.

When images of particles in a urine sample are taken by the biological sample imaging device <NUM>, a plurality of sample containers <NUM> are transported to the suction position while being held in the rack as described above. The entirety of the liquid flow channel <NUM> is, in the initial state, filled with the washing liquid <NUM> ((a) of <FIG>). Next, the pump controller 20c causes the syringe pump <NUM> to suck a certain volume of air <NUM> while the suction nozzle <NUM> is not inserted in the sample container <NUM>, thereby introducing the certain volume of air <NUM> to an end of the liquid flow channel <NUM> to form an air gap (S101 in <FIG>, and <FIG> of <FIG>). For example, about <NUM>µL of air <NUM> may be sucked into the liquid flow channel <NUM>.

Next, the suction nozzle actuator <NUM> causes the suction nozzle <NUM> to be inserted in one sample container <NUM> together with an agitation nozzle (not shown) (S102 in <FIG>). Then, the agitation controller <NUM> causes the biological sample <NUM> contained in the sample container <NUM> to be agitated (S103 in <FIG>).

Thereafter, the pump controller 20c forwardly drives the piston actuator 24a to suck a specified amount of the biological sample <NUM> from the sample container <NUM> (S104 in <FIG>). For example, about <NUM>µL of the biological sample <NUM> may be sucked into the liquid flow channel <NUM>. During the suction process, the abnormality determination unit 20e monitors a rapid decrease in the conductivity outputted from the second sensor 28b, that is, it monitors passing of the air gap. If the conductivity does not rapidly decrease, the abnormality determination unit 20e determines that the operation of the syringe pump <NUM> is abnormal, and ends the process.

When suction of the specified amount of biological sample <NUM> is completed ((c) of <FIG>), the abnormality determination unit 20e determines whether or not the conductivity outputted from the second sensor 28b is equal to or higher than a predetermined threshold (S105 in <FIG>). If the conductivity is less than the predetermined threshold, the abnormality determination unit 20e determines that abnormality has occurred in the biological sample <NUM>, and ends the process.

Thereafter, the suction nozzle controller 20f causes the suction nozzle actuator <NUM> to pull up the suction nozzle <NUM> from the sample container <NUM> (S106 in <FIG>). Next, the pump controller 20c causes air to be sucked from the suction nozzle <NUM> (S107 in <FIG>). In the initial stage of this suction process, a shortage monitoring period is set, and the abnormality determination unit 20e monitors a rapid decrease in the conductivity outputted from the second sensor 28b. If the conductivity rapidly decreases, the abnormality determination unit 20e determines that the biological sample <NUM> is less than the specified amount, and ends the process.

The pump controller 20c causes the suction of air to be performed until the air <NUM> is detected by the first sensor 28a (S108 in <FIG>). The suction of air causes the biological sample <NUM> having been introduced into the liquid flow channel <NUM> to move to the downstream side. If the conductivity that is outputted from the first sensor 28a rapidly decreases, it can be determined that the air <NUM> has taken the place of the object, i.e., the washing liquid <NUM>, located at the detection position of the first sensor 28a. At this timing, the downstream end of the air <NUM> (air gap) reaches the detection position of the first sensor 28a ((d) of <FIG>).

Thereafter, the pump controller 20c further causes a predetermined amount of air to be sucked (S109 in <FIG>, <FIG> of <FIG>). Specifically, the first determination unit 20a determines whether or not the suction amount of the syringe pump <NUM> has reached the predetermined amount, and the pump controller 20c stops the operation of the syringe pump <NUM> when the suction amount of the syringe pump <NUM> has reached the predetermined amount. The suction amount of the syringe pump <NUM> in S109 is a value obtained by adding the volume of the air <NUM> (air gap) to the internal capacity from the detection position of the first sensor 28a to the first position A. Thus, the downstream end 104a of the biological sample <NUM> reaches the first position A. The first position A may be provided about <NUM>µL upstream of the upstream end 14c of the inner space 14e of the imaging cell <NUM>. The operation from S104 to S109 corresponds to the first operation of the syringe pump <NUM>.

Thereafter, the pump controller 20c instructs the piston actuator 24a to perform reverse actuation, thereby causing a predetermined amount of air to be discharged from the upstream end of the liquid flow channel <NUM> (S110 in <FIG>). Specifically, the second determination unit 20b determines whether or not the discharge amount of the syringe pump <NUM> has reached the predetermined amount, and the pump controller 20c stops the operation of the syringe pump <NUM> if the discharge amount of the syringe pump <NUM> has reached the predetermined amount. The discharge amount of the syringe pump <NUM> is equal to the internal capacity from the first position A to the second position B. For example, the discharge amount may be about <NUM>µL. Thus, the downstream end 104a of the biological sample <NUM> reaches the second position B ((f) of <FIG>). The operation in S110 corresponds to the second operation of the syringe pump <NUM>.

Next, the pump controller 20c instructs the piston actuator 24a to perform forward actuation, and causes a predetermined amount of air to be sucked (S111 in <FIG>). Specifically, it is determined whether or not the suction amount of the syringe pump <NUM> has reached the predetermined amount, and the pump controller 20c stops the operation of the syringe pump <NUM> if the suction amount of the syringe pump <NUM> has reached the predetermined amount. The suction amount of the syringe pump <NUM> is equal to the internal capacity of the liquid flow channel <NUM> from the second position B to the third position C. For example, this suction amount may be about <NUM>µL. Thus, the downstream end 104a of the biological sample <NUM> reaches the third position C ((g) of <FIG>). For example, the capacity between the downstream end 14d of the imaging cell <NUM> and the third position C, which is the imaging range, may be <NUM>µL. In this case, if the capacity of the inner space 14e of the imaging cell <NUM> is <NUM>µL, a portion corresponding to <NUM>µL to <NUM>µL from the downstream end 104a of the biological sample <NUM> is filled in the inner space 14e of the imaging cell <NUM>. The operation in S111 corresponds to the third operation of the syringe pump <NUM>.

According to the aforementioned pump control, the biological sample <NUM> is filled in the inner space 14e of the imaging cell <NUM>, and the imaging controller 20d causes image data of the biological sample <NUM> to be generated (S112 in <FIG>).

After the image-taking, washing of the liquid flow channel <NUM> and the syringe pump <NUM> is performed (S113 in <FIG>). Specifically, the suction nozzle controller 20f instructs the suction nozzle actuator <NUM> to insert the suction nozzle <NUM> in the washing chamber <NUM>. At this timing, the piston of the syringe pump <NUM> is sufficiently pulled out, and the washing liquid stored in the washing liquid container <NUM> flows into the syringe pump <NUM> when the solenoid valve between the syringe pump <NUM> and the washing liquid container <NUM> is opened. The washing liquid immediately reaches the tip of the suction nozzle <NUM>, whereby the inside of the liquid flow channel <NUM> and the inside of the syringe pump <NUM> are washed throughout. The air, the urine sample, and the washing liquid are discharged from the suction nozzle <NUM> to be stored in the waste liquid container <NUM>. Thereafter, the solenoid valve provided in a drain of the washing chamber <NUM> is temporarily closed, whereby the washing liquid is stored in the washing chamber <NUM>. Thereafter, the solenoid valve is opened. Thus, the outside of the suction nozzle <NUM> is also washed. The washing liquid may be supplied from the suction nozzle <NUM> or from an exclusive channel, to the washing chamber <NUM>. When washing of the liquid flow channel <NUM> and the syringe pump <NUM> has ended, the suction nozzle <NUM> is pulled out from the washing chamber <NUM>, and is moved to a stand-by position to ready for suction of the urine sample from the next sample container <NUM>.

<FIG> is a distribution chart of the large particles after the biological sample <NUM> has been caused to flow through the liquid flow channel <NUM> by the biological sample imaging device <NUM>. <FIG> is a distribution chart of the small particles after the biological sample <NUM> has been caused to flow through the liquid flow channel <NUM> by the biological sample imaging device <NUM>. In <FIG>, a broken line indicates the number of large particles per unit volume (about <NUM>/µL) that is measured by a flow cytometer. The broken line indicates the number of large particles per unit volume in the sample container <NUM>. As shown in <FIG>, after the biological sample <NUM> has been caused to flow through the liquid flow channel <NUM>, the number of large particles per unit volume is <NUM> times or more at any position within the range of <NUM>µL from the downstream end 104a of the biological sample <NUM>. Accordingly, it is found that, also within the imaging range, the number of large particles per unit volume is <NUM> times or more as compared with the original number of large particles per unit volume.

In <FIG>, a broken line indicates the number of small particles per unit volume (about <NUM>/µL) that is measured by a flow cytometer. It is found that <NUM>% or more is ensured as compared with the original number of small particles per unit volume.

According to the aforementioned biological sample imaging device <NUM>, the pump controller 20c causes the syringe pump <NUM> to perform the first operation, whereby large particles such as the epithelial cells <NUM> and the urinary casts <NUM> can be concentrated around the downstream end 104a of the biological sample <NUM>. Thereafter, the pump controller 20c causes the syringe pump <NUM> to perform the second operation, whereby the large particles concentrated around the downstream end 104a of the biological sample <NUM> can be dispersed to the upstream side. The inner space 14e of the imaging cell <NUM> is filled with the biological sample <NUM> that has been caused to forwardly and reversely flow through the liquid flow channel <NUM>. Therefore, a sufficient number of large particles are present in the imaging cell <NUM>, and moreover, these large particles are moderately dispersed, whereby the individual large particles can be reflected in images taken by the camera <NUM>. As a result, the accuracy of the urine test can be improved.

Of the large particles in the urine sample whose images are taken by the biological sample imaging device <NUM>, the epithelial cells <NUM> appear in urine due to damage of a kidney or the urinary tract, and images thereof are important information for judging which portion of the kidney or urinary tract is damaged and the extent of the damage. For example, the images of the epithelial cells <NUM> are used for diagnosis of diseases such as cystitis and urethritis. The urinary casts <NUM> appear in urine when a renal tubular lumen is temporarily closed and thereafter urine flows again, and images thereof are also important information for judging which portion of the kidney or urinary tract is abnormal and the extent of the abnormality. For example, the images of the urinary casts <NUM> are used for diagnosis of diseases such as chronic nephritis, glomerulonephritis, pyelonephritis, and nephrotic syndrome. Generally, only a small number of large particles such as the epithelial cells <NUM> and the urinary casts <NUM> are contained in a urine sample. However, even a small number of large particles provide clinically very important findings as described above. According to the biological sample imaging device <NUM>, the large particles in the urine sample, which provide such important findings, can be efficiently reflected in images so as not to overlap each other, through the aforementioned concentration and dispersion processes. Thus, according to the present embodiment, the reliability of the urine test can be significantly improved.

The present invention is not limited to the above embodiment. Various modifications of the above embodiment can be made, and these modifications are also within the scope of the present invention. For example, while the first sensor 28a and the second sensor 28b are used in the above description, these sensors are not necessarily required for controlling the position of the downstream end 104a of the biological sample <NUM>.

The third operation by the pump controller 20c is not necessarily required. That is, as shown in <FIG>, the first position A may be provided on the downstream side relative to the imaging range of the imaging cell <NUM>, and the second position B may be provided at the downstream end of the imaging range of the imaging cell <NUM> or on the downstream side relative to the downstream end. In this case, the inner space 14e of the imaging cell <NUM> is filled with the biological sample <NUM> immediately after the second operation has been performed. Thus, the time interval from start of suction of the biological sample <NUM> to image-taking by the camera <NUM> can be reduced.

Claim 1:
A biological sample imaging device comprising:
a liquid flow channel (<NUM>) through which a liquid biological sample containing particles flows, the liquid flow channel (<NUM>) having, at a predetermined position, an imaging range within which images of the particles contained in the biological sample are taken;
a pump (<NUM>) configured to cause the biological sample, which has been introduced from a container into the liquid flow channel (<NUM>), to flow in a forward direction from an upstream side toward a downstream side or in a direction reverse to the forward direction; and
a pump controller (20c) configured to cause the pump (<NUM>) to sequentially perform a first operation of causing the biological sample introduced into the liquid flow channel (<NUM>) to flow in the forward direction, and a second operation of causing the biological sample to flow in the reverse direction; wherein the biological sample imaging device further comprises:
an imaging unit configured to take, within the imaging range, images of the particles contained in the biological sample that remains in the liquid flow channel (<NUM>) after the second operation, wherein the imaging unit comprises an imaging cell (<NUM>); wherein after a predetermined time period has passed, the particles are precipitated at a bottom of the imaging cell (<NUM>), and wherein the imaging unit is configured to take the images of the particles precipitated in the imaging cell (<NUM>).