Capsule probe for noninvasive determination of duodenum calcium absorption rate and application thereof

Abstract

The invention discloses a capsule probe for noninvasive determination of duodenum calcium absorption rate and application thereof. The head of a capsule body is provided with a detection module, the middle of the capsule body is provided with a fixing module, the tail of the capsule body is provided with a medicine storage cavity, and the interior of the capsule body is provided with a control module; a slow release opening is formed in the top of the detection module; the fixing module comprises a balloon and an inflation assembly, and a position sensing assembly is arranged on the outer surface of the balloon; the control module comprises a power supply module, a data processing module and a flow control unit. The pH sensor and the pressure sensor cooperate to serve as a position sensing assembly to recognize the duodenum, physical fixation is conducted in combination with the sacculus driven by the micro air pump, it is ensured that detection occurs at the accurate anatomical position, the position of the probe is stable in the whole detection period, and the detection accuracy is improved. Measurement errors caused by probe displacement or too fast passing due to intestinal tract movement are avoided.

Description

Technical Field

[0001] This invention relates to the field of biomedical detection technology, specifically to a capsule probe for non-invasive determination of duodenal calcium absorption rate and its application. Background Technology

[0002] Accurate measurement of duodenal calcium absorption rate is of significant clinical importance for the diagnosis and treatment evaluation of calcium metabolism-related diseases (such as osteoporosis and parathyroid dysfunction). Currently, existing methods for measuring duodenal calcium absorption rate have several limitations: Anatomical visualization-based fluorescence attenuation rate measurement is the gold standard, but it is an invasive procedure requiring invasive or endoscopic manipulation of experimental animals or patients, resulting in significant trauma, poor repeatability, and the inability to achieve dynamic real-time monitoring; conventional blood biochemical markers can only indirectly reflect the overall calcium absorption situation and cannot precisely locate the duodenal region, resulting in low temporal and spatial resolution; some non-invasive detection devices lack effective intestinal fixation mechanisms, making them easily carried away by intestinal peristalsis, causing the detection site to deviate from the target area, and compromising the accuracy of the results; furthermore, most detection devices use only a single detection method, leading to large detection errors and weak anti-interference capabilities.

[0003] Therefore, developing a device that can achieve non-invasive, precise, and real-time localization to the duodenum and detect calcium absorption rate through multi-parameter collaborative detection has become an urgent technical problem to be solved in this field. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a capsule probe for non-invasive measurement of duodenal calcium absorption rate and its application, achieving precise fixation of the duodenal region and multi-parameter synergistic detection, thereby improving the accuracy and non-invasiveness of calcium absorption rate measurement.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a capsule probe for non-invasive determination of duodenal calcium absorption rate, comprising a capsule body; the capsule body is provided with a detection module at the head, a fixing module in the middle, a drug storage cavity at the tail, and a control module inside;

[0007] The detection module includes a photosensitive sensor and a resistance sensor, and the resistance sensor has a slow-release port on its top;

[0008] The fixing module includes a balloon and an inflation assembly. The outer surface of the balloon is provided with a position sensing assembly. The inflation assembly includes a miniature air pump. The air port of the miniature air pump is connected to the balloon. A one-way valve is provided at the air port of the miniature air pump.

[0009] The control module includes a power supply module, a data processing module, and a flow control unit; the data processing module is electrically connected to the detection module, the position sensing component, the inflation component, and the flow control unit, and the power supply module supplies power to the data processing module, the detection module, the position sensing component, the inflation component, and the flow control unit.

[0010] Furthermore, the position sensing component includes a pH sensor and a pressure sensor, which work together to determine whether the capsule probe has reached the duodenum by detecting the pH value and peristaltic pressure in the intestine.

[0011] Furthermore, the photosensitive sensor is a high-sensitivity silicon-based photodiode with a detection wavelength range of 510-520nm; the resistive sensor is a platinum electrode.

[0012] Furthermore, the inflation pressure of the micro air pump is 0.02-0.05 MPa.

[0013] Furthermore, the drug storage cavity is filled with a fluorescent calcium agent.

[0014] Furthermore, the flow control unit controls the release rate of the fluorescent calcium agent to be 0.1-0.5 mL / h.

[0015] Furthermore, the capsule body is provided with a capsule shell.

[0016] Secondly, the present invention provides a method for determining the duodenal calcium absorption rate using the above-mentioned capsule probe, comprising the following steps:

[0017] S1: Inject a fluorescent calcium agent into the drug storage chamber of the capsule probe, and then insert the capsule probe into the digestive tract of the subject to be tested;

[0018] S2: The position sensing component determines whether the capsule probe has reached the duodenal region, and when it arrives, the inflation component inflates the balloon to fix the probe to the duodenal wall.

[0019] S3: Activate the flow control unit to release fluorescent calcium into the duodenum at a constant rate;

[0020] S4: Simultaneously or after the release of the fluorescent calcium agent, the photosensitive sensor detects the rate of fluorescence intensity decay within the capsule, and the resistance sensor detects the change in the resistance value of the solution in the duodenum.

[0021] S5: Based on the fluorescence intensity decay rate and resistance value change, the duodenal calcium absorption rate is calculated.

[0022] A third objective of this invention is to provide the application of the above-described capsule probe in the preparation of medical devices for diagnosing or evaluating diseases related to calcium absorption disorders.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] (1) Non-invasive and precise positioning: The present invention uses a capsule sustained-release method to deliver the capsule into the body without the need for dissection, thus achieving non-invasive detection; the location of the duodenum is identified by pH sensor and pressure sensor in collaboration, and the balloon fixation device is used to ensure that the capsule probe is stably fixed at the target detection site, avoiding interference from intestinal peristalsis and improving the spatial accuracy of detection.

[0025] (2) Multi-parameter collaborative detection: This invention integrates a photosensitive sensor and a resistance sensor to measure calcium absorption-related parameters from two dimensions: fluorescence decay rate and ion concentration change. The detection accuracy is improved by multi-parameter complementarity, and the anti-interference ability is stronger. The selected fluorescein sodium-labeled calcium chloride solution has good biocompatibility and fluorescence stability, ensuring reliable detection signal. It shows high detection accuracy in both normal and duodenal mucosa-damaged rat models.

[0026] In summary, the capsule probe of this invention has a wide range of applications, a high degree of automation in the detection process, is easy to operate, and can be recycled and reused, providing a reliable tool for the study of the mechanisms of calcium metabolism-related diseases. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the capsule probe of the present invention.

[0028] Figure 2 This is a cross-sectional view of the capsule probe of the present invention.

[0029] The following components are marked in the diagram: 1. Capsule shell; 2. Photosensitive sensor; 3. Resistance sensor; 4. Balloon; 5. Inflation assembly; 6. Position sensing assembly; 7. Drug storage chamber; 8. Sustained-release port; 9. Flow control unit; 10. Data processing module; 11. Power supply module; 12. Miniature air pump; 13. One-way valve; 14. Miniature peristaltic pump; 15. pH sensor; 16. Pressure sensor; 17. Miniature solenoid valve.

[0030] Figure 3This diagram illustrates the testing of the present invention and the fluorescence attenuation method in the duodenum of normal and SD rat models with duodenal mucosal damage. In the diagram: A - Fluorescence excitation under direct anatomical visualization of the capsule probe releasing fluorescein-containing calcium in the SD rat model with duodenal mucosal damage (fluorescein residue at 15 min); B - Fluorescence excitation under direct anatomical visualization of the capsule probe releasing fluorescein-containing calcium in normal SD rats (fluorescein residue at 15 min); C - Paired dumbbell plot showing the accuracy of calcium absorption rate determination in the duodenum of the SD rat model with duodenal mucosal damage using the two methods. With the fluorescence attenuation method as the gold standard, the accuracy of the balloon resistance method of the present invention is 92.98%; D - Paired dumbbell plot showing the accuracy of calcium absorption rate determination in the duodenum of normal SD rats using the two methods. With the fluorescence attenuation method as the gold standard, the accuracy of the balloon resistance method of the present invention is 95.87%.

[0031] Figure 4 This diagram illustrates the correlation and accuracy of the results obtained using the present invention and the fluorescence attenuation method in the duodenum of SD rat models with duodenal mucosa damage. In the diagram: A - Pearson correlation analysis of the release rate of fluorescein-containing calcium in the SD rat model with duodenal mucosa damage using the present invention and the fluorescence attenuation method (R=0.966, P<0.001); B - Pearson correlation analysis of the release rate of fluorescein-containing calcium in the SD rat model with duodenal mucosa damage using the present invention and the fluorescence attenuation method (R=0.965, P<0.001); C - Bland-Altman descriptive statistics of the calcium absorption rate in the duodenum of the SD rat model with duodenal mucosa damage measured by the two methods (R=0.965, P<0.001); D - Bland-Altman descriptive statistics of the calcium absorption rate in the duodenum of normal SD rats measured by the two methods (R=0.966, P<0.001); Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0033] Example 1: Fabrication of the capsule probe structure

[0034] 1. Capsule shell 1: Made of medical-grade polycarbonate by injection molding, with dimensions of 10mm in length and 4mm in diameter. Sensor mounting holes and sustained-release ports 8 are reserved on the side wall of the shell;

[0035] 2. Detection Module: The photosensitive sensor 2 uses a silicon-based photodiode of model S1133, whose detection wavelength range covers the emission wavelength of sodium fluorescein (510-520nm), and can accurately capture the fluorescence intensity decay changes during the release of fluorescent calcium agents; the resistance sensor 3 uses a platinum wire electrode (0.1mm in diameter), which has good conductivity and biocompatibility, and can stably measure the resistance value of calcium-containing solutions in the intestine, and then convert it into calcium ion concentration; the photosensitive sensor 2 and the resistance sensor 3 are respectively fixed to the reserved holes in the shell with epoxy resin;

[0036] 3. Fixation Module: The balloon 4 is made of medical-grade latex material with a volume of 0.5mL. When not inflated, it fits the outer shell. When inflated, its expansion diameter can reach 8-10mm, achieving fixation inside the duodenum. The inflation component 5 uses a miniature air pump 12 (model: FML-06) and a one-way valve 13. The position sensing component 6 uses a miniature pH sensor 15 (model: PH-BTA) and a pressure sensor 16 (model: MPX2010DP).

[0037] 4. Drug release module: The drug storage chamber 7 is made of medical glass with a volume of 1.5mL. The flow control unit 9 is a miniature peristaltic pump 14 (model: BT100-1L). The slow-release port 8 is made of silicone with an inner diameter of 0.2mm.

[0038] 5. Data processing module 10: It uses an STM32L431 microcontroller as the core processor and integrates a wireless transmission module (model: nRF24L01) for data transmission; the power supply module 11 uses a CR2032 button battery with a capacity of 220mAh.

[0039] 6. Assembly: Assemble each module according to the attached... Figure 1-2 The layout is integrated, with each module connected by micro wires and fixed with medical-grade adhesive. The joints are sealed to ensure waterproofing and corrosion resistance.

[0040] like Figure 1-2 As shown, the present invention provides a capsule probe, including a capsule body and an outer capsule shell 1; the capsule body has a detection module at the head, a fixing module in the middle, a drug storage cavity 7 for storing fluorescent calcium agent at the tail, and a control module inside.

[0041] The detection module includes a photosensitive sensor 2 and a resistance sensor 3. The resistance sensor 3 has a slow-release port 8 on its top. The photosensitive sensor 2 is used to measure the change in fluorescence intensity of the fluorescent calcium agent inside the capsule shell 1, thereby obtaining the release rate of the fluorescent calcium agent. The resistance sensor 3 is used to measure the change in ion concentration of the calcium-containing solution released into the intestine, thereby obtaining the absorption rate of calcium ions. The fluorescent calcium agent is a calcium chloride solution labeled with sodium fluorescein. Sodium fluorescein, as a fluorescent agent, has the characteristics of good fluorescence stability, high biocompatibility, and no irritation to the intestine.

[0042] The fixing module includes a balloon 4 and an inflation assembly 5. A position sensing assembly 6 is provided on the outer surface of the balloon 4. The inflation assembly 5 includes a miniature air pump 12, the air inlet of which is connected to the balloon 4. A one-way valve 13 is provided at the air inlet of the miniature air pump 12. The miniature air pump 12 inflates the balloon 4, with the inflation pressure controlled between 0.02-0.05 MPa to ensure that the balloon 4 adheres and is fixed to the intestinal wall without damaging the intestinal mucosa. The one-way valve 13 is used to maintain stable pressure inside the balloon 4. After detection, a miniature solenoid valve 17 is used to... The position sensing component 6 includes a pH sensor 15 and a pressure sensor 16. By detecting the pH value in the intestine (the pH value of the duodenum is usually 6.0-7.5) and the peristaltic pressure, it jointly determines whether the capsule probe has reached the duodenum, with an accuracy rate of ≥98%. After receiving the signal from the position sensing component 6, the inflation component 5 inflates the balloon 4, causing the balloon 4 to expand and adhere to the duodenal wall for fixation, preventing the capsule probe from being carried away by intestinal peristalsis. After the detection is completed, the inflation component 5 deflates, causing the balloon 4 to contract, and the capsule probe is expelled from the body with intestinal peristalsis.

[0043] The control module includes a power supply module 11, a data processing module 10, and a flow control unit 9. The data processing module 10 is electrically connected to the detection module, the position sensing component 6, the inflation component 5, and the flow control unit 9. It is used to receive sensor detection data, control the working status of the fixing module and the drug release module, and perform preliminary processing on the detection data. The power supply module 11 uses a miniature button battery to power the data processing module 10, the detection module, the position sensing component 6, the inflation component 5, and the flow control unit 9. The flow control unit 9 is used to control the release of fluorescent calcium from the miniature peristaltic pump 14 and the slow-release port 8 into the duodenum at a constant rate. It can accurately control the release rate of fluorescent calcium to 0.1-0.5 mL / h, ensuring that the calcium concentration changes stably and controllably during the detection process.

[0044] Example 2: Application of the capsule probe in a rat model

[0045] Establishment of experimental animal models:

[0046] Normal SD rat model: Healthy SPF-grade SD rats, weighing 200-250g, were selected and fed an acclimatization diet for 1 week before use.

[0047] Duodenal mucosal damage model in SD rats: Aspirin was ground and dissolved in physiological saline and administered by gavage at a dose of 100 mg / kg body weight once a day for 7 consecutive days to establish a duodenal mucosal damage model.

[0048] Capsule probe preparation: Inject sodium fluorescein-labeled calcium chloride solution (sodium fluorescein concentration of 0.1 mmol / L and calcium chloride concentration of 1 mmol / L) into the drug storage chamber of the capsule probe, and check that the working status of each module is normal before use.

[0049] 1. Grouping of experimental animals: Forty healthy SPF-grade SD rats were randomly divided into a normal group (n=20) and a model group (n=20). The model group was induced with aspirin to establish a duodenal mucosal destruction model.

[0050] 2. Detection Procedure: The capsule probe prepared according to Example 1 was injected with a fluorescein-labeled calcium chloride solution, and two groups of rats were subjected to gavage testing. The capsule probe was administered to the rats via gavage. After entering the intestine, the position sensing component monitored the intestinal pH and peristaltic pressure in real time. When parameters consistent with duodenal characteristics were detected, the data processing module controlled the inflation component to inflate the balloon, fixing the capsule probe to the duodenal wall. Subsequently, the flow control unit controlled the sustained-release port to release the fluorescein-containing calcium agent at a rate of 0.3 mL / h. The photosensitive sensor monitored the fluorescence intensity of the remaining fluorescein-containing calcium agent inside the capsule in real time, and the resistance sensor monitored the resistance value of the calcium solution in the intestine in real time. The detection data was transmitted to the data processing module in real time, and the detection time was 30 minutes. After the detection was completed, the inflation component deflated, and the capsule probe was expelled from the body with intestinal peristalsis. It could be reused after being recovered (after sterilization). The detection data of the photosensitive sensor and the resistance sensor were recorded. Simultaneously, each rat was dissected after the detection, and the gold standard data was obtained using the direct-view fluorescence decay rate measurement method. The results are as follows: Figure 3 As shown;

[0051] 3. Data Processing: SPSS 26.0 statistical software was used. The changes in calcium concentration and absorption rate measured by fluorescence decay rate under direct anatomical visualization were used as the gold standard. Bland-Altman analysis was used to evaluate the consistency between the capsule probe detection results and the gold standard. Pearson correlation analysis was used to calculate the correlation coefficient, and an accuracy fitting curve was constructed. The conversion formula between fluorescence decay rate and calcium concentration was determined based on the standard curve established in the preliminary experiment, and the conversion formula between resistance value and calcium ion concentration was derived based on the Nernst equation. The results are as follows: Figure 4As shown, the correlation coefficient r of the normal group was 0.965, and the accuracy fitting curve reached 95.87%; the correlation coefficient r of the model group was 0.955, and the accuracy fitting curve reached 92.98%, both higher than the preset standard, indicating that the capsule probe has high detection accuracy in both normal and duodenal mucosal injury states.

[0052] 4. Repeatability verification: Three repeated tests were performed on the normal group rats, and the coefficient of variation (CV) was 2.3%, indicating that the capsule probe has good repeatability.

[0053] Example 3: Comparative Experiment of Single Sensor Detection and the "Photoelectric Synergistic" Detection of the Present Invention

[0054] 1. Grouping of experimental animals: Thirty normal SD rats, the same as those in Example 2, were randomly divided into three groups: Experimental group (photoelectric synergistic group): The photosensitive sensor and the resistance sensor of this invention were used for synergistic detection (same as in Example 2); Control group 1 (single photosensitive sensor group): Only the photosensitive sensor was retained, and the resistance sensor detection function was turned off. Other parameters were the same as those of the experimental group; Control group 2 (single resistance sensor group): Only the resistance sensor was retained, and the photosensitive sensor detection function was turned off. Other parameters were the same as those of the experimental group.

[0055] 2. Detection indicators: accuracy of calcium absorption rate, Pearson correlation coefficient (r) and coefficient of variation (CV) between the detection results and the gold standard (fluorescence attenuation method under direct anatomical vision).

[0056] 3. Data Processing: SPSS 26.0 statistical software was used. One-way ANOVA was employed to compare the differences in accuracy and correlation coefficients among the three groups. Tukey's method was used for multiple comparisons between groups. P < 0.05 was considered statistically significant. Bland-Altman analysis was also used to assess the consistency of each group with the gold standard. The accuracy of the experimental group was significantly higher than that of control groups 1 and 2 (P < 0.001), the correlation coefficient was closer to 1, and the coefficient of variation was significantly lower (P < 0.001). This indicates that single-sensor detection has significant interference (such as fluorescence of impurities in the intestine, fluctuations in ion concentration, etc.). Single photosensitive sensors are easily affected by fluorescence interference from intestinal contents, leading to misjudgment of fluorescence decay rate. Single resistive sensors are easily affected by ion interference from intestinal secretions, leading to deviations in calcium ion concentration conversion. The "photoelectric synergy" of this invention uses fluorescence signal and resistance signal to mutually correct each other. The fluorescence intensity reflects the total amount of calcium released, and the resistance value reflects the ion absorption efficiency. The two complement each other to eliminate single interference factors, solving the detection accuracy problem that cannot be overcome by single methods.

[0057] Group Accuracy (%) Pearson correlation coefficient (r) Coefficient of variation (CV, %) 95% CI range experimental group 95.87 0.965 2.3 (-291, 314) Control group 1 76.32 0.782 8.7 (-654, 721) Control group 2 73.15 0.756 9.2 (-689, 753)

[0058] Table 1. Comparative experimental statistics of single sensor detection and the "photoelectric synergy" detection of this invention.

[0059] Example 4: Experiment on the effect of different inflation pressures on detection results

[0060] 1. Grouping of experimental animals: Thirty normal SD rats from Example 2 were randomly divided into three groups: experimental group (optimal pressure group): inflation pressure 0.02-0.05 MPa (same as Example 2); control group 3 (low pressure group): inflation pressure 0.005-0.01 MPa (lower than the range defined in this invention); control group 4 (high pressure group): inflation pressure 0.06-0.09 MPa (higher than the range defined in this invention).

[0061] 2. Detection indicators: capsule probe fixation success rate, intestinal mucosal damage rate (observe whether there is congestion, edema or mucosal morphological changes in the intestinal wall after dissection), accuracy of calcium absorption rate, and stability of the detection process (whether the probe shifts).

[0062] 3. Data Processing: SPSS 26.0 statistical software was used. The differences in fixation success rate and mucosal injury incidence among the three groups were compared by chi-square test. The differences in accuracy were compared by one-way ANOVA. P < 0.05 was considered statistically significant. Control Group 3 (Low-Pressure Group): Insufficient inflation pressure resulted in poor adhesion between the balloon and the intestinal wall, with a fixation success rate of only 30%. 70% of the probes shifted due to intestinal peristalsis, causing the detection site to deviate from the duodenum, reducing the accuracy to 62.45%, which failed to meet the detection requirements. Control Group 4 (High-Pressure Group): Excessive inflation pressure caused the balloon to over-inflate, resulting in intestinal mucosal congestion and morphological changes in 60% of the rats (non-invasive failure). Although the fixation success rate was 100%, the accuracy was only 81.32% due to mucosal damage affecting the physiological state of calcium absorption, and it did not meet the core requirements of non-invasive detection. Experimental Group (0.02-0.05 MPa): 100% fixation success rate, no intestinal mucosal damage, no probe displacement, and an accuracy rate of 95.87%. This demonstrates that the inflation pressure range defined by this invention can achieve stable fixation while ensuring non-invasiveness, representing the optimal parameter range that balances fixation effectiveness and biosafety.

[0063] Group Inflation pressure (MPa) Fixed success rate (%) Incidence of intestinal mucosal injury (%) Detection accuracy (%) experimental group 0.02-0.05 100 0 95.87 Control group 3 0.005-0.01 30 0 62.45 Control group 4 0.06-0.09 100 60 81.32

[0064] Table 2. Statistical table of the effect of different inflation pressures on the test results.

Claims

1. A capsule probe for non-invasive determination of duodenal calcium absorption rate, comprising a capsule body; characterized in that: The capsule body has a detection module at the head, a fixing module in the middle, a drug storage cavity (7) at the tail, and a control module inside. The detection module includes a photosensitive sensor (2) and a resistance sensor (3), and the top of the resistance sensor (3) is provided with a slow-release port (8); The fixing module includes a balloon (4) and an inflation assembly (5). The outer surface of the balloon (4) is provided with a position sensing assembly (6). The inflation assembly (5) includes a miniature air pump (12). The air port of the miniature air pump (12) is connected to the balloon (4). A one-way valve (13) is provided at the air port of the miniature air pump (12). The control module includes a power supply module (11), a data processing module (10), and a flow control unit (9); the data processing module (10) is electrically connected to the detection module, the position sensing component (6), the inflation component (5), and the flow control unit (9), and the power supply module (11) supplies power to the data processing module (10), the detection module, the position sensing component (6), the inflation component (5), and the flow control unit (9).

2. The capsule probe according to claim 1, characterized in that: The position sensing component (6) includes a pH sensor (15) and a pressure sensor (16), which together detect the pH value and peristaltic pressure in the intestine to determine whether the capsule probe has reached the duodenum.

3. The capsule probe according to claim 1, characterized in that: The photosensitive sensor (2) is a high-sensitivity silicon-based photodiode with a detection wavelength range of 510-520nm; the resistive sensor (3) is a platinum electrode.

4. The capsule probe according to claim 1, characterized in that: The inflation pressure of the micro air pump (12) is 0.02-0.05 MPa.

5. The capsule probe according to claim 1, characterized in that: The drug storage chamber (7) is filled with fluorescent calcium agent.

6. The capsule probe according to claim 5, characterized in that: The flow control unit (9) controls the release rate of the fluorescent calcium agent to be 0.1-0.5 mL / h.

7. The capsule probe according to claim 1, characterized in that: The capsule body is provided with a capsule shell (1).

8. A method for determining the duodenal calcium absorption rate using a capsule probe as described in any one of claims 1-7, characterized in that: Includes the following steps: S1: Inject a fluorescent calcium agent into the drug storage chamber (7) of the capsule probe, and then insert the capsule probe into the digestive tract of the subject to be tested; S2: The position sensing component (6) determines whether the capsule probe has reached the duodenal region, and when it arrives, the balloon (4) is inflated by the inflation component (5) to fix the probe to the duodenal wall; S3: Activate the flow control unit (9) to release fluorescent calcium into the duodenum at a constant rate; S4: At the same time or after the release of the fluorescent calcium agent, the rate of decay of fluorescence intensity in the capsule is detected by the photosensitive sensor (2), and the change of resistance value of the solution in the duodenum is detected by the resistance sensor (3); S5: Based on the fluorescence intensity decay rate and resistance value change, the duodenal calcium absorption rate is calculated.

9. The use of the capsule probe as described in any one of claims 1-7 in the preparation of a medical device for diagnosing or evaluating diseases related to calcium absorption disorders.

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