Multi-mode activity measuring method and system based on automatic picking and placing of medical radioactive substances

Abstract

The invention relates to the technical field of activity measurement of medical radioactive substances, and discloses a multi-mode activity measurement method and system based on automatic taking and placing of medical radioactive substances, and the system comprises a measurement device and a software control unit, a lead shielding chamber, a plurality of ionization chamber limiting point positions and a gantry structure three-axis linkage mechanism are arranged in a lead glass wall of the measuring device; a plurality of hole point positions used for containing the storage barrels are arranged in the lead chamber body, a mechanical arm used for grabbing the storage barrels is arranged in the three-axis linkage mechanism, the software control unit controls the mechanical arm to move in the X-axis direction, the Y-axis direction and the Z-axis direction, and moving, taking, placing and positioning of the storage barrels between the lead shielding chamber and the ionization chamber are completed. Radiation protection during activity measurement can be achieved, influences of other radioactive substances can be eliminated during measurement, high-precision positioning of medical radioactive substances can be controlled, geometric position consistency during activity measurement each time can be guaranteed, and multi-mode activity measurement of various medical radioactive substances and various activity meters can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of activity measurement of medical radioactive materials, and in particular to a multi-mode activity measurement method and system based on automatic taking and placing of medical radioactive materials. Background Art

[0002] With the advancement of science and technology and the development of nuclear medicine equipment, nuclear medicine plays an irreplaceable role in clinical diagnosis. With the promotion and application of domestic nuclear reactors and cyclotrons, more and more medical radioactive substances are used in nuclear medicine clinical diagnosis and treatment, and the demand for nuclear medicine imaging diagnosis and nuclide therapy continues to increase and improve, thus promoting the development of medical radioactive substances such as radioisotope reagents and solutions based on nuclear reactors and cyclotrons. In order to verify the activity status of these medical radioactive substances and ensure the accuracy of their values, it is necessary to provide activity values ​​for these medical radioactive substances.

[0003] On the other hand, the radioactivity meter with 4πγ ionization chamber as detector is an instrument for quantitatively measuring the activity of radioactive materials. It is an important device for verifying the quality of radioactive materials in nuclear medicine. It is widely used because of its convenience, high repeatability, good long-term stability and wide range, especially in the production of medical radioactive materials and medical and health departments. Therefore, it is necessary to regularly test the medical activity meter to determine its measurement accuracy, so as to achieve quality control of the medical activity meter.

[0004] In all the above situations, the activity meter is required to measure the activity value of radioactive materials. However, many measurement institutions have not carried out professional radiation protection design. Operators need to repeatedly operate medical radioactive materials during the actual measurement process, which will cause unnecessary radiation damage. In addition, it is not convenient for operators to operate during the actual measurement process, and the degree of automation is not high, which affects work efficiency. In addition, since the actual measurement process usually requires the use of multiple medical radioactive materials, when one of the medical radioactive materials is measured in the 4πγ ionization chamber, other radioactive materials may also affect its activity value. On the other hand, the use of an activity meter to measure the activity value of radioactive materials is a relative measurement method, which requires that the measurement conditions of the radioactive material to be measured and the radionuclide standard source used for calibration are as consistent as possible, especially the axial and radial geometric positions of the medical radioactive material and the standard source in the ionization chamber should be as similar as possible. In addition, the optimal geometric position with the maximum axial response and the minimum radial response should be selected for measurement to reduce the impact of changes in the geometric position of the radioactive material.

[0005] At present, no relevant content has been found for the multi-mode activity measurement method and system based on the automatic placement of medical radioactive materials. For the use of activity meters to measure the fixed value of activity of medical radioactive materials, no relevant content has been found for the radiation protection design, and no relevant content has been found for the reduction of the impact of changes in the geometric position of medical radioactive materials.

[0006] The shortcomings of the prior art are mainly:

[0007] 1. Many measurement institutions have not carried out professional radiation protection design. Operators need to repeatedly operate medical radioactive materials during the actual measurement process, which will cause unnecessary radiation damage. In addition, it is not convenient for operators to operate during the actual measurement process, and the degree of automation is not high, which affects work efficiency.

[0008] 2. Since the actual measurement process usually requires the use of multiple medical radioactive substances, when one of the medical radioactive substances is measured in a 4πγ ionization chamber, other radioactive substances may also affect its activity value.

[0009] 3. Using an activity meter to determine the activity of radioactive materials is a relative measurement method, which requires that the measurement conditions of the radioactive material to be measured and the radionuclide standard source used in calibration should be as consistent as possible, especially the axial and radial geometric positions of the radioactive material and the standard source in the 4πγ ionization chamber should be as similar as possible, otherwise it will cause unnecessary errors. However, the existing technology is to manually place the radioactive material in the 4πγ ionization chamber for each measurement, which cannot ensure the consistency of the geometric position of the radioactive material in the ionization chamber.

[0010] 4. The best geometric position with the maximum axial response and the minimum radial response should be selected for measurement to reduce the impact of the change in the geometric position of the radioactive material. However, the existing technology is to manually place the radioactive material into the 4πγ ionization chamber, and it is impossible to control the radioactive material to be positioned at the geometric position with the maximum axial response and the minimum radial response with high precision.

[0011] 5. More importantly, since many medical radioactive substances are radioactive reagents or solutions, they need to be stored in ampoules or penicillin bottles. These containers are easily damaged during operation, causing leakage of medical radioactive substances. Some of them will contaminate the ionization chamber and cause equipment damage, and some will pollute the environment and cause personal injury, thus causing serious radioactive contamination accidents.

[0012] Terminology explanation:

[0013] Automatic picking and placing: Medical radioactive materials are automatically taken out of the container or placed in the designated location through a designed mechanical automation device.

[0014] Multi-mode: For example, using medical radioactive materials as measurement standards to perform quality control on activity meters; or using a certain activity meter as a standard activity meter, and using the standard activity meter and the activity meter to be tested to measure the same medical radioactive material respectively, to achieve quality control of the activity meter to be tested; or using the activity meter as a measurement standard to perform fixed-value activity measurement on medical radioactive materials.

[0015] Activity meter: It is mainly composed of a 4πγ ionization chamber and an instrument host. Activity meters are mainly used in nuclear medicine diagnosis, treatment, and radiopharmaceutical production and sales. Summary of the invention

[0016] In view of the above problems, the purpose of the present invention is to provide a multi-mode activity measurement method and system based on automatic placement of medical radioactive materials, which can achieve effective radiation protection during activity measurement, eliminate the influence of other medical radioactive materials during measurement, and ensure the consistency of the geometric position of medical radioactive materials during each activity measurement, and control the high-precision positioning of medical radioactive materials. A new storage tube is designed to effectively protect medical radioactive materials and has no effect on activity measurement. It can also achieve multi-mode activity measurement in the quality evaluation of multiple medical radioactive materials and multiple activity meters, and realize automation and batch continuous measurement. The technical solution is as follows:

[0017] A multi-mode activity measurement system based on automatic placement of medical radioactive materials, including a measuring device and a software control unit. The measuring device includes a lead glass enclosure with lead glass windows, a lead shielding room arranged inside the lead glass enclosure, a plurality of limit points for placing ionization chambers, and a gantry structure three-axis linkage mechanism;

[0018] The lead shielding room comprises a lead room body with a storage space therein and an openable lead room cover arranged above the lead room body; the storage space of the lead room body is provided with a plurality of hole points for placing storage cylinders, and the storage cylinders are used to store medical radioactive substances;

[0019] The three-axis linkage mechanism of the gantry structure is provided with a manipulator for grabbing the storage tube. The software control unit controls the manipulator to perform high-precision movement in the XYZ axis direction. The positioning accuracy in the XYZ axis direction can reach up to ±0.005mm, completing the movement, placement and positioning of the storage tube between the lead shielding room and the ionization chamber.

[0020] The software control unit is used to control the measuring device and is linked to the state of the lead glass window on the lead glass fence. When the lead glass window is open, the software control unit is prohibited from operating. The software control unit can only operate after the lead glass window is manually closed.

[0021] Further, the three-axis linkage mechanism of the gantry structure includes an X-axis precision linear guide, a right Y-axis precision linear guide, a left Y-axis precision linear guide and a Z-axis precision linear guide;

[0022] The right Y-axis precision linear guide and the left Y-axis precision linear guide are parallel to each other and are respectively arranged on both sides of the lead shielding room and the ionization room; one end of the X-axis precision linear guide is slidably connected to the right Y-axis precision linear guide, and the other end is slidably connected to the left Y-axis precision linear guide; the Z-axis precision linear guide is perpendicular to the X-axis precision linear guide and the right Y-axis precision linear guide, and is slidably connected to the X-axis precision linear guide through a connecting component; the manipulator is slidably connected to the Z-axis precision linear guide;

[0023] The software control unit controls the X-axis precision linear guide to move in the Y-axis direction, controls the Z-axis precision linear guide to move in the X-axis direction, and controls the manipulator to move in the Z-axis direction.

[0024] Furthermore, two 4πγ ionization chambers are placed at the ionization chamber limit points, which are numbered as ionization chamber No. 1 and ionization chamber No. 2 respectively.

[0025] Furthermore, the hole points for placing the storage cylinder are an m×n array, and the inner wall is provided with an isolation layer made of plastic; the lead chamber cover is opened and closed by a stepper motor; the storage cylinder is made of synthetic plastic, and a portion for being grasped by a robot is provided on the top, and a sealing cover is provided on the bottom.

[0026] The first mode activity measurement method based on automatic placement of medical radioactive materials uses medical radioactive materials as the measurement standard. The steps for quality control of the activity meter are as follows:

[0027] Step 501: Medical radioactive materials including multiple nuclides should be selected as measurement standards, put into storage cylinders, and then put into holes in the lead shielding room, and the lead room cover is closed; each medical radioactive material is numbered according to the corresponding hole points, and a standard source library is established;

[0028] Step 502: placing the 4πγ ionization chamber of the activity meter to be tested at the limit position of the ionization chamber; operating the manipulator to align the center coordinates of the ionization chamber, reading the real-time coordinates of the manipulator and saving them;

[0029] Step 503: setting the nuclide setting conditions of the activity meter to be measured, closing the lead glass window, and opening the lead chamber cover;

[0030] Step 504: According to the hole point number and the number of the ionization chamber to be tested, the storage cylinder containing the required nuclide is grabbed by the manipulator and moved from the lead shielding room to above the center point of the selected ionization chamber;

[0031] Step 505: Starting from the wellhead of the selected ionization chamber, the storage tube is controlled by the manipulator to move downward to change the axial position of the medical radioactive material in the ionization chamber; the axial response of each position is realized by formula (1), and the axial response F z The measured value A of the activity meter at each position during axial movement after deducting the background Z Compared with the standard value of medical radioactive materials A s Divide to get:

[0032] F z =A Z / A s (1)

[0033] Step 506: Position the medical radioactive material at the geometric position with the maximum axial response; control the storage tube to move radially by the manipulator, and the radial response of each position is realized by formula (2), and the radial response F a The measured value A of the activity meter at each position after deducting the background during radial movement a Compared with the standard value of medical radioactive materials A s Divide to get:

[0034] F a =A a / A s (2)

[0035] Step 507: Control the storage tube to be positioned at the optimal geometric position with the maximum axial response and the minimum radial response, calculate the relative inherent error E of the activity meter to be measured under the setting conditions of the nuclide of the medical radioactive material according to formula (3), complete the calibration evaluation of the activity meter to be measured under the nuclide, and realize its quality control:

[0036]

[0037] The calibration coefficient of the activity meter to be measured for the corresponding nuclide is k = A s / A, A is the measured value of the activity meter at this geometric position after deducting the background.

[0038] Furthermore, if the second ionization chamber is to be measured, the measured storage tube is moved from the measured ionization chamber to the second ionization chamber, and steps 505 to 507 are repeated to obtain the evaluation result of the second ionization chamber, and so on;

[0039] If the first ionization chamber that has been measured needs to be measured under another nuclide setting condition, the measured storage tube is moved from the measured ionization chamber to the lead shielding room, and then the hole point corresponding to the storage tube number is placed, and then the medical radioactive material of the second nuclide is selected, and steps 504 to 507 are repeated to complete the calibration evaluation of the first ionization chamber under the second nuclide, and so on;

[0040] If the measurement work is completed, the measured medical radioactive material will be moved from the measured ionization chamber to the lead shielding room, and then placed in the hole corresponding to the number of its storage tube, and the lead chamber cover will be closed to end the measurement.

[0041] The second mode activity measurement method based on automatic placement of medical radioactive materials uses one of the activity meters as a standard activity meter and the other activity meters as activity meters to be tested. The same medical radioactive material is measured by the standard activity meter and the activity meter to be tested. The steps for quality control of the activity meter to be tested are as follows:

[0042] Step 701: Put the medical radioactive materials including various nuclides into storage cylinders respectively, and then put them into the holes of the lead shielding room, and close the lead room cover; number each medical radioactive material according to the corresponding hole, and establish a standard source library;

[0043] Step 702: placing the 4πγ ionization chamber of the standard activity meter at the position of ionization chamber No. 1, and placing the 4πγ ionization chamber of the activity meter to be tested at the position of ionization chamber No. 2; operating the manipulator to align the center coordinates of the two ionization chambers, reading the real-time coordinates of the manipulator and saving them;

[0044] Step 703: Set the nuclide setting conditions of the standard activity meter and the activity meter to be tested, close the lead glass window, and open the lead chamber cover;

[0045] Step 704: According to the hole point number and the number of the No. 1 ionization chamber, the robot grasps the storage cylinder containing the required radionuclide and moves it from the lead shielding room to above the center point of the No. 1 ionization chamber;

[0046] Step 705: Starting from the wellhead of No. 1 ionization chamber, the storage tube is controlled by the manipulator to move downward to change the axial position of the medical radioactive material in the ionization chamber; the measured value of the activity meter at each position after deducting the background is measured, and the maximum value of the measured value is set as the maximum axial response value;

[0047] Step 706: Position the medical radioactive material at the geometric position with the maximum axial response, and control the storage tube to move radially by the manipulator; measure the measured value of the activity meter at each position after deducting the background, and set the minimum value of the measured value as the minimum radial response value;

[0048] Step 707: Control the storage tube to be positioned at the optimal geometric position of the maximum axial response and the minimum radial response of the No. 1 ionization chamber, and the measured value of the activity meter at this position after deducting the background is the standard value A. s ;

[0049] Step 708: Move the measured storage tube from ionization chamber No. 1 to ionization chamber No. 2, and use the A measured by the standard activity meter sAs standard values, the axial response and radial response of ionization chamber No. 2 were measured;

[0050] Step 709: Control the storage tube to be positioned at the optimal geometric position of the maximum axial response and the minimum radial response of the No. 2 ionization chamber, calculate the relative inherent error E of the activity meter to be measured under the current nuclide setting conditions of the medical radioactive material; complete the calibration evaluation of the activity meter to be measured under the nuclide to achieve its quality control.

[0051] Furthermore, if the activity meter to be measured is to be measured under another nuclide setting condition, the measured storage tube is moved from the No. 2 ionization chamber to the lead shielding room, and then placed in the hole corresponding to the storage tube number, and then the medical radioactive material of the second nuclide is selected, and steps 704 to 709 are repeated to complete the calibration evaluation of the activity meter to be measured under the second nuclide, and so on;

[0052] If the measurement work is completed, the measured medical radioactive material will be moved from the measured ionization chamber to the lead shielding room, and then placed in the hole corresponding to the number of its storage tube, and the lead chamber cover will be closed to end the measurement.

[0053] The third mode activity measurement method based on automatic placement of medical radioactive materials uses an activity meter as a measurement standard to measure the activity value of medical radioactive materials as follows:

[0054] Step 801: Place the 4πγ ionization chamber of the activity meter used as the measurement standard at the position of the No. 1 ionization chamber or the No. 2 ionization chamber, and use the 4πγ ionization chamber as the standard ionization chamber; put a batch of medical radioactive materials to be tested into storage tubes respectively, and then put them into the holes of the lead shielding room respectively, and close the lead room cover; number each medical radioactive material according to the corresponding hole position, and establish a source library;

[0055] Step 802: operate the manipulator to align the center coordinates of the standard ionization chamber, and read and save the real-time coordinates of the manipulator;

[0056] Step 803: Set the nuclide setting conditions of the activity meter used as the measurement standard, close the lead glass window, and open the lead chamber cover;

[0057] Step 804: According to the hole point number and the standard ionization chamber number, the storage cylinder containing the radioactive medical material to be tested is grabbed by the manipulator and moved from the lead shielding room to above the center point of the standard ionization chamber;

[0058] Step 805: According to the calibration evaluation of the activity meter, two different operations are selected:

[0059] 1) If the activity meter has a calibration coefficient k for the corresponding nuclide of the medical radioactive material to be measured h, and the optimal geometric position for activity measurement in the ionization chamber has been calibrated, the storage tube is positioned to the optimal geometric position in the ionization chamber by the manipulator, and the measured value A of the activity meter after deducting the background is measured; then the activity calibration value A of the medical radioactive material to be measured k The formula is used to obtain the value of medical radioactive substances;

[0060] A k =k h ×A (4)

[0061] 2) If the activity meter does not measure the calibration coefficient k of the corresponding nuclide of the medical radioactive material to be measured h , or if the optimal geometric position for activity measurement in the ionization chamber is not calibrated, the axial response and radial response of the ionization chamber are obtained in the same manner as steps 705 to 706; the storage tube is controlled by the manipulator to be positioned at the optimal geometric position of the maximum axial response and the minimum radial response of the ionization chamber, and the measurement value of the activity meter at this position after deducting the background is obtained as the activity calibration value of the medical radioactive substance to be measured, thereby achieving the fixed value of the medical radioactive substance.

[0062] Furthermore, if other medical radioactive materials need to be measured, the measured storage tube is moved from the ionization chamber to the lead shielding chamber, and then placed in the hole corresponding to the storage tube number, and then the second medical radioactive material is selected, and steps 804 to 805 are repeated to complete the measurement and setting of the second medical radioactive material, and so on;

[0063] If the measurement work is completed, the measured medical radioactive material will be moved from the ionization chamber to the lead shielding room, and then placed in the hole corresponding to the number of its storage tube, and the lead chamber cover will be closed to end the measurement.

[0064] The beneficial effects of the present invention are:

[0065] 1) The present invention realizes radiation protection during activity measurement

[0066] In order to prevent medical radioactive substances from emitting radiation that may harm the human body or the environment, a lead shielding room and a lead glass enclosure are set up to weaken and shield the rays to achieve the purpose of safety, making it convenient to observe the operation of the device outside the lead glass enclosure.

[0067] 2) The present invention solves the problem that when one medical radioactive substance is measured in a 4πγ ionization chamber, other medical radioactive substances may also affect its activity measurement.

[0068] 3) The present invention ensures the geometrical position consistency of medical radioactive materials during each activity measurement

[0069] Through precise mechanical structure design, high-precision movement of the manipulator can be achieved, thereby achieving accurate reproduction of the activity of medical radioactive materials.

[0070] 4) The present invention can control the high-precision positioning of medical radioactive materials, thereby reducing the impact of changes in the geometric position of medical radioactive materials and achieving high-precision activity measurement of medical radioactive materials.

[0071] 5) The present invention designs a new storage tube

[0072] The storage tube provided by the present invention is used to store medical radioactive materials, and can effectively protect the medical radioactive materials during the measurement and storage process. Moreover, it can avoid causing radioactive contamination on a larger scale, reducing economic losses and personal injuries. The storage tube is made of synthetic plastic, has no attenuation effect on radiation, and has no effect on activity measurement. In addition, the storage tube is designed to facilitate the grasping of the manipulator, and by combining the high-precision movement of the manipulator, it can further ensure the high-precision positioning of the medical radioactive materials.

[0073] 6) By flexibly combining a variety of medical radioactive substances and a variety of activity meters, the present invention can realize a multi-mode and multi-functional activity measurement method.

[0074] 7) Realize automation and batch continuous measurement to improve work efficiency

[0075] The present invention realizes the automatic placement and loading of medical radioactive materials, and the entire measurement method, process and system are automated. In addition, the present invention can continuously measure the activity of m×n medical radioactive materials, and can also continuously measure, calibrate and evaluate multiple 4πγ ionization chambers. All of these greatly improve work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] Figure 1 This is a schematic diagram of the structure of the multi-mode activity measurement device based on automatic placement of medical radioactive materials in the present invention.

[0077] Figure 2 This is a structural diagram of a lead shielding room in an embodiment of the present invention.

[0078] Figure 3 Schematic diagram of the numbering method for the holes for placing storage cylinders in a lead shielding room.

[0079] Figure 4 Schematic diagram of a storage cylinder in an embodiment of the present invention.

[0080] Figure 5 This is the flow chart of the high-precision activity measurement method of the first mode.

[0081] Figure 6 Schematic diagram of the storage tube moving axially and radially along the 4πγ ionization chamber.

[0082] Figure 7 This is the flow chart of the high-precision activity measurement method of the second mode.

[0083] Figure 8 This is the flow chart of the high-precision activity measurement method of the third mode.

[0084] In the figure: 1-lead glass wall, 2-lead shielding room, 3-right Y-axis precision linear guide, 4-X-axis precision linear guide, 5-Z-axis precision linear guide, 6-left Y-axis precision linear guide, 7-No. 1 ionization chamber, 8-No. 2 ionization chamber, 9-manipulator, 10-lead chamber body, 11-isolation layer, 12-storage cylinder, 13-lead chamber cover, 14-stepping motor; 15-part grasped by the manipulator, 16-sealing cover; 17-medical radioactive material; 18-4πγ ionization chamber; 19-connecting parts. DETAILED DESCRIPTION

[0085] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0086] The present invention aims to solve the problems in the prior art such as lack of professional radiation protection design, low automation, mutual interference of medical radioactive materials, inability to ensure the consistency of geometric positions of medical radioactive materials placed in ionization chambers, inability to control high-precision positioning of medical radioactive materials, and low work efficiency. A multi-mode activity measurement method and system based on automatic placement of medical radioactive materials is provided. The multi-mode high-precision activity measurement system mainly consists of two parts: a measuring device and a software control unit.

[0087] Figure 1 This is a schematic diagram of the structure of a measuring device for a multi-mode high-precision activity measurement system based on automatic placement of medical radioactive materials. In the figure: 1-lead glass enclosure, 2-lead shielding room, 3-right Y-axis precision linear guide, 4-X-axis precision linear guide, 5-Z-axis precision linear guide, 6-left Y-axis precision linear guide, 7-No. 1 ionization chamber, 8-No. 2 ionization chamber, 9-manipulator.

[0088] The measuring device of the multi-mode high-precision activity measurement system adopts the basic principle of the three-axis linkage design of the gantry structure. The operator inputs the operation instructions and sets the parameters in the human-machine interface of the software control unit to control the manipulator 9 to perform high-precision movement in the X-axis precision linear guide 4, the left Y-axis precision linear guide 6, the right Y-axis precision linear guide 3 and the Z-axis precision linear guide 5 in the XYZ axis direction. The positioning accuracy in the XYZ axis direction can reach up to ±0.005mm.

[0089] The gantry structure three-axis linkage mechanism of the present embodiment includes an X-axis precision linear guide 4, a right-side Y-axis precision linear guide 3, a left-side Y-axis precision linear guide 6 and a Z-axis precision linear guide 5; the right-side Y-axis precision linear guide 3 and the left-side Y-axis precision linear guide 6 are parallel to each other and are respectively arranged on both sides of the lead shielding room 2 and the ionization room; one end of the X-axis precision linear guide 4 is slidably connected to the right-side Y-axis precision linear guide 3, and the other end is slidably connected to the left-side Y-axis precision linear guide 6; the Z-axis precision linear guide 5 is perpendicular to the X-axis precision linear guide 4 and the right-side Y-axis precision linear guide 3, and is slidably connected to the X-axis precision linear guide 4 through a connecting component 19; the manipulator 9 is slidably connected to the Z-axis precision linear guide 5;

[0090] The software control unit controls the X-axis precision linear guide rail 4 to move in the Y-axis direction, controls the Z-axis precision linear guide rail 5 to move in the X-axis direction, and controls the manipulator 9 to move in the Z-axis direction.

[0091] The gantry structure adopts a three-axis linkage design, and the double-end support structure of the gantry can also effectively reduce the errors caused by insufficient single-sided support and cantilever droop. Compared with single-sided drive, the double-sided drive of the gantry can also effectively reduce the errors caused by yaw. The XYZ axes of the manipulator movement all use precision linear guides as guide mechanisms, and precision ball screws and stepper motors as transmission devices. The present invention controls the three-axis manipulator to move to the corresponding position of the lead shielding room, take out the medical radioactive material, move to the 4πγ ionization chamber position, and put down the medical radioactive material, thereby completing the high-precision positioning and layout of the medical radioactive material. The displacement parameters on the Z-axis coordinate are set by the software control unit, and the motor drives the ball screw of the electric translation stage to drive the guide rail slider to move up and down, which can ensure that the medical radioactive material can reach the same position of the ionization chamber each time the activity is measured, and the activity of the medical radioactive material can be accurately reproduced.

[0092] The present invention adopts mechanical structures such as precise linear guides to ensure high-precision positioning. By setting the displacement parameters on the XYZ axis coordinates through a software control unit, the medical radioactive material can be controlled to be positioned at the optimal geometric position of the maximum axial response and the minimum radial response with high precision, thereby reducing the impact of the change in the geometric position of the medical radioactive material and realizing high-precision activity measurement of the medical radioactive material.

[0093] According to the size of the measuring device and the specific working mode, multiple 4πγ ionization chambers of the medical activity meter can be placed. The embodiment of the present invention is two 4πγ ionization chambers, namely ionization chamber No. 1 and ionization chamber No. 2. A variety of ionization chambers can be selected according to the specific working mode. After fixing their positions, the center coordinates of the various ionization chambers can be measured and saved.

[0094] For the safety of operators, radiation protection design is required. In order to prevent the radiation emitted by medical radioactive substances from causing harm to the human body or the environment, the present invention provides a lead glass enclosure 1 and a lead shielding room 2 to weaken the radiation shielding to achieve the purpose of safety.

[0095] The lead glass enclosure 1 of this embodiment is designed with a lead glass window with a push-pull structure. When it is opened, the ionization chamber and other equipment can be put in or taken out. When it is closed, the operation of the equipment can be observed outside the lead glass enclosure 1. The lead glass enclosure 1 is a glass containing lead oxide. As the lead oxide content increases, the density, refractive index, dispersion, dielectric constant, radiation absorption coefficient and other performance index values ​​of the glass increase. The wall thickness of the comprehensive lead shielding room 2 can better prevent the radiation emitted by medical radioactive substances from causing harm to the human body or the environment.

[0096] The lead shielding room 2 of this embodiment not only has the function of radiation protection, but also can prevent the influence of other radioactive substances when the medical radioactive substances are measured in the 4πγ ionization chamber.

[0097] Figure 2 The structure diagram of the lead shielding room in the embodiment of the present invention is shown in the figure: 10-lead room body, 11-isolation layer, 12-storage cylinder, 13-lead room cover, 14-stepping motor.

[0098] The lead chamber body 10 of this embodiment is lead with a purity of 99%, without defects such as sand holes and bubbles, and fully prevents radiation leakage. The stepper motor 14 is used as a transmission structure to control the automatic opening of the lead chamber cover 13 during measurement, and to control it to automatically close after the measurement is completed.

[0099] The storage tube 12 of this embodiment is used to store medical radioactive materials. It is stored in the hole points of the lead shielding room. The hole points can be set as an m×n array according to work needs, and the storage tubes 12 can be numbered according to the corresponding positions. The hole points in the embodiment of the present invention are a 4×3 array, and the storage tubes at the corresponding positions are numbered as follows: Figure 3 shown.

[0100] The isolation layer 11 is made of plastic and is used to isolate the storage tube 12 from the lead to prevent the lead from contaminating the storage tube 12. It can also play a buffering role to prevent the storage tube 12 from being damaged by collision.

[0101] Figure 4 The schematic diagram of the storage cylinder in the embodiment of the present invention is shown in the figure: 15 is the part grasped by the robot, 16 is the sealing cover.

[0102] The storage tube 12 provided by the present invention is used to store medical radioactive materials, which can effectively protect the medical radioactive materials during the measurement and storage process, and prevent the medical radioactive materials from being damaged and causing radioactive contamination. Moreover, if the medical radioactive materials placed in the storage tube are damaged or leaked, the storage tube containing the damaged medical radioactive materials can be directly handled together to avoid causing radioactive contamination on a larger scale, thereby reducing economic losses and personal injuries. The storage tube 12 is made of synthetic plastic, which has no attenuation effect on radiation and no effect on activity measurement. Therefore, placing the storage tube 12 containing medical radioactive materials in a 4πγ ionization chamber for measurement has the same effect as placing the medical radioactive materials in a 4πγ ionization chamber alone for measurement. When storing medical radioactive materials, the storage tube can be placed in a hole point in a lead shielding room. In addition, the storage tube is designed to facilitate the grabbing of the manipulator, and by combining the high-precision movement of the manipulator, the high-precision positioning of the medical radioactive materials can be further guaranteed.

[0103] The gripping part 15 of the robot in this embodiment is designed to be integrated with the storage tube 12, and its shape is designed to facilitate the gripping of the robot 9, and the two can be in close contact during gripping. The front end of the robot 9 uses an electric claw with a self-locking mechanism as a functional component for the gripping action, which is disengaged when powered on and clamped when powered off. This ensures that in the event of an accidental power outage, the storage tube 12 will not fall off the robot 9 and cause a radioactive hazard.

[0104] The sealing cover 16 of this embodiment is used to seal the storage tube 12 containing medical radioactive materials to prevent the medical radioactive materials from falling out and causing radioactive contamination.

[0105] The present invention provides a multi-mode high-precision activity measurement method based on automatic placement of medical radioactive materials. The process of the high-precision activity measurement method is different according to different modes.

[0106] 1. The first mode

[0107] The first mode is to use medical radioactive materials as the measurement standard to perform quality control on the activity meter. Figure 5 The following is a flow chart of the high-precision activity measurement method for this mode. Figure 5 As shown, the method includes:

[0108] Step 501: Before measuring, a series of medical radioactive materials of various nuclides such as Co-60 and I-131 should be selected as measurement standards, and they should be placed in a storage tube, and then placed in the hole position of the lead shielding room, and the lead room cover should be closed. Each medical radioactive material is numbered according to the corresponding hole position, and a standard source library is established, that is, one number corresponds to one hole position, one storage tube, and the medical radioactive material in the storage tube.

[0109] Step 502: Place the 4πγ ionization chamber of the activity meter to be tested at the limit position of ionization chamber No. 1 or ionization chamber No. 2. Operate the manipulator to align the center coordinates of the ionization chamber. At this time, read the real-time coordinates of the manipulator in the coordinate display status bar of the software control unit, and then save and set the center coordinates of the ionization chamber in the coordinate parameter configuration part of the software control unit. The set parameters can be read and modified later.

[0110] Step 503: Set the nuclide setting conditions of the activity meter to be measured. Close the lead glass window, use the software control unit to operate the lead chamber cover to open, and proceed to the next step when the software operation interface shows that the lead chamber cover has been fully opened.

[0111] Step 504: Click the hole point number of the medical radioactive material of the required nuclide and the number of the ionization chamber to be tested in the software operation interface. After confirming that the number selection is correct, click Grab, and the robot will move the storage tube containing the selected radioactive material from the lead shielding room to above the center point of the selected ionization chamber.

[0112] Step 505: The storage tube moves along the axial and radial directions of the 4πγ ionization chamber as follows: Figure 6 As shown. The displacement parameters of the Z-axis coordinates of the manipulator are set by the software control unit, and the storage tube is controlled to be placed into the selected ionization chamber along the axial direction with high precision. Starting from the wellhead of the ionization chamber, the manipulator controls the storage tube to move downward to change the axial position of the medical radioactive material in the ionization chamber. The axial response of each position is realized by formula (1). The axial response F z The measured value A of the activity meter at each position during axial movement after deducting the background Z Compared with the standard value of medical radioactive materials A s Divide them to get the value.

[0113] F z =A Z / A s (1)

[0114] Step 506: Position the medical radioactive material at the maximum axial response position, set the displacement parameters of the XY axis coordinates of the manipulator through the software control unit, and control the storage tube to move radially with high precision. The radial response of each position is realized by formula (2). The radial response F a The measured value A of the activity meter at each position after deducting the background during radial movement a Compared with the standard value of medical radioactive materials A s Divide them to get the value.

[0115] F a =A a / A s (2)

[0116] Step 507: The displacement parameters of the XYZ axis coordinates of the manipulator are set by the software control unit, and the storage tube is positioned to the optimal geometric position of the maximum axial response and the minimum radial response with high precision, and the relative inherent error E of the activity meter to be measured under the setting conditions of the nuclide of the medical radioactive material is calculated according to formula (3). This completes the calibration evaluation of the activity meter to be measured under the nuclide, and realizes its quality control.

[0117]

[0118] Where: A is the measured value of the activity meter at this geometric position after deducting the background, A s is the standard value of the medical radioactive material. The calibration coefficient of the activity meter to be measured for the corresponding nuclide is k = A s / A.

[0119] Step 508: According to work needs, three operations can be selected at this time:

[0120] P501: The first operation is to move the measured storage tube from the measured ionization chamber to the second ionization chamber if the second ionization chamber needs to be measured, and repeat steps 505 to 507 to obtain the evaluation result of the second ionization chamber, and so on.

[0121] P502: The second operation is that if the first measured ionization chamber is to be measured under other nuclide setting conditions, the measured storage tube is moved from the measured ionization chamber to the lead shielding room, and then placed in the hole corresponding to the storage tube number, and then the medical radioactive material of the second nuclide is selected, and steps 504 to 507 are repeated to complete the calibration evaluation of the first ionization chamber under the second nuclide, and so on.

[0122] P503: The third operation is to move the measured medical radioactive material from the measured ionization chamber to the lead shielding room if the measurement work is completed, and then put it into the hole corresponding to the number of its storage tube, close the lead chamber cover, and end the measurement.

[0123] 2. The second mode

[0124] The second mode is to use one of the activity meters as the standard activity meter and the other activity meters as the activity meters to be tested. The same medical radioactive material is measured by the standard activity meter and the activity meter to be tested respectively, so as to achieve quality control of the activity meters to be tested. Figure 7 The following is a flow chart of the high-precision activity measurement method for this mode. As shown in the figure, the method includes:

[0125] Step 701: Before measuring, a series of medical radioactive materials of various nuclides should be selected, loaded into storage tubes, and then placed into the holes of the lead shielding room, and the lead room cover is closed. Each medical radioactive material is numbered according to the corresponding hole, and a source library is established, that is, one number corresponds to one hole, one storage tube, and the medical radioactive material in the storage tube.

[0126] Step 702: Place the 4πγ ionization chamber of the standard activity meter at the position of ionization chamber No. 1, and place the 4πγ ionization chamber of the activity meter to be tested at the position of ionization chamber No. 2. Operate the manipulator to align the center coordinates of the two ionization chambers, and at this time read the real-time coordinates of the manipulator in the coordinate display status bar of the software control unit, and then save and set the center coordinates of the two ionization chambers in the coordinate parameter configuration part of the software control unit.

[0127] Step 703: Set the nuclide setting conditions of the standard activity meter and the activity meter to be tested. Close the lead glass window, use the software control unit to operate the lead chamber cover to open, and proceed to the next step when the software operation interface shows that the lead chamber cover is fully opened.

[0128] Step 704: Click the hole point number of the medical radioactive material of the required nuclide and the number of ionization chamber No. 1 in the software operation interface. After confirming that the number selection is correct, click Grab, and the robot will move the storage tube containing the selected medical radioactive material from the lead shielding room to above the center point of ionization chamber No. 1.

[0129] Step 705: Set the displacement parameters of the Z-axis coordinates of the manipulator, and control the storage tube to be placed into the No. 1 ionization chamber along the axial direction with high precision. Starting from the wellhead of the ionization chamber, the manipulator controls the storage tube to move downward to change the axial position of the medical radioactive material in the ionization chamber, and measure the measured value of the activity meter at each position after deducting the background, and set its maximum value as the maximum axial response value.

[0130] Step 706: Position the medical radioactive material at the position of maximum axial response, set the displacement parameters of the XY axis coordinates of the manipulator through the software control unit, control the radial movement of the storage tube with high precision, measure the measurement value of the activity meter at each position after deducting the background, and set its minimum value as the minimum radial response value.

[0131] Step 707: The displacement parameters of the XYZ axis coordinates of the manipulator are set by the software control unit, and the storage tube is positioned to the optimal geometric position of the maximum axial response and the minimum radial response of the No. 1 ionization chamber with high precision. The measured value of the activity meter at this position after deducting the background is the standard value A. s .

[0132] Step 708: Move the measured storage tube from ionization chamber No. 1 to ionization chamber No. 2, and use the A measured by the standard activity meter s As standard values, the axial response and radial response of the No. 2 ionization chamber are obtained in the same manner as in steps 505 to 506.

[0133] Step 709: The displacement parameters of the XYZ axis coordinates of the manipulator are set by the software control unit, and the storage tube is positioned to the optimal geometric position of the maximum axial response and the minimum radial response of the No. 2 ionization chamber with high precision, and the relative inherent error E of the activity meter to be measured under the setting conditions of the nuclide of the medical radioactive material is calculated according to Formula 3. The calibration coefficient of the activity meter to be measured for the corresponding nuclide is k = A / A s This completes the calibration evaluation of the activity meter under the nuclide to be measured and realizes its quality control.

[0134] Step 710: Depending on the work requirements, two operations can be selected at this time:

[0135] P701: The first operation is that if the activity meter to be measured is to be measured under other nuclide setting conditions, the measured storage tube will be moved from ionization chamber No. 2 to the lead shielding room, and then placed in the hole corresponding to the storage tube number, and then the medical radioactive material of the second nuclide will be selected, and steps 704 to 709 will be repeated to complete the calibration evaluation of the activity meter to be measured under the second nuclide, and so on.

[0136] P702: The second operation is to move the measured medical radioactive material from the measured ionization chamber to the lead shielding room if the measurement work is completed, and then put it into the hole corresponding to the number of its storage tube, close the lead chamber cover, and end the measurement.

[0137] 3. The third mode

[0138] The third mode is to use the activity meter as the measurement standard to measure the activity value of medical radioactive substances. Figure 8 The following is a flow chart of the high-precision activity measurement method for this mode. As shown in the figure, the method includes:

[0139] Step 801: Place the 4πγ ionization chamber of the activity meter used as the measurement standard at the position of ionization chamber No. 1 or ionization chamber No. 2, and the 4πγ ionization chamber is used as the standard ionization chamber. Put a batch of medical radioactive materials to be tested into each storage tube, and then put them into the hole positions of the lead shielding room, and close the lead chamber cover. Number each medical radioactive material according to the corresponding hole position, and establish a source library. The source library of the embodiment of the present invention can store up to 12 medical radioactive materials. That is, one number corresponds to one hole position, one storage tube, and the medical radioactive material in the storage tube.

[0140] Step 802: operate the manipulator to align the center coordinates of the standard ionization chamber. At this time, read the real-time coordinates of the manipulator in the coordinate display status bar of the software control unit, and then save and set the center coordinates of the ionization chamber in the coordinate parameter configuration part of the software control unit.

[0141] Step 803: Set the nuclide setting conditions of the activity meter as the measurement standard. Close the lead glass window, use the software control unit to operate the lead chamber cover to open, and proceed to the next step when the software operation interface shows that the lead chamber cover has been fully opened.

[0142] Step 804: Click on the hole number of the medical radioactive material of the required nuclide to be tested and the standard ionization chamber number in the software operation interface. After confirming that the number selection is correct, click Grab. The robot will move the storage tube containing the selected medical radioactive material from the lead shielding room to above the center point of the standard ionization chamber.

[0143] Step 805: Based on the calibration evaluation of the activity meter, two operations can be selected:

[0144] P801: The first operation is if the activity meter has a calibration factor k corresponding to the nuclide of the medical radioactive material to be measured. h , and the optimal geometric position for activity measurement in the ionization chamber has been calibrated, the displacement parameters of the XYZ axis coordinates of the manipulator are set through the software control unit, and the storage tube is positioned to the optimal geometric position in the ionization chamber with high precision, and the measured value A of the activity meter after deducting the background is measured. Then the activity calibration value A of the medical radioactive material to be measured k Formula (4) is used to obtain the value of medical radioactive substances.

[0145] A k =k h ×A (4)

[0146] P802: The second operation is if the activity meter does not measure the calibration coefficient k of the corresponding nuclide of the medical radioactive material to be measured h , or if the optimal geometric position for activity measurement in the ionization chamber is not calibrated, the axial response and radial response of the ionization chamber are obtained in the same manner as in steps 705 to 706. Then, the displacement parameters of the XYZ axis coordinates of the manipulator are set by the software control unit, and the storage tube is precisely controlled to be positioned at the optimal geometric position of the maximum axial response and the minimum radial response of the ionization chamber. The measured value of the activity meter at this position after deducting the background is the activity calibration value of the medical radioactive material to be measured, thereby achieving the fixed value of the medical radioactive material.

[0147] Step 806: Depending on the work requirements, two operations can be selected at this time:

[0148] P803: The first operation is that if other medical radioactive materials need to be measured, the measured storage tube is moved from the ionization chamber to the lead shielding chamber, and then the hole corresponding to the storage tube number is placed, and then the second medical radioactive material is selected, and steps 804 to 805 are repeated to complete the measurement and setting of the second medical radioactive material, and so on. The embodiment of the present invention can continuously measure and set the values ​​of up to 12 medical radioactive materials, which greatly improves the work efficiency.

[0149] P804: The second operation is to move the measured medical radioactive material from the ionization chamber to the lead shielding room if the measurement work is completed, and then put it into the hole corresponding to the number of its storage tube, close the lead chamber cover, and end the measurement.

[0150] The present invention flexibly combines a variety of medical radioactive materials and a variety of activity meters to realize a multi-mode high-precision activity measurement method not limited to the above three modes. For example, using medical radioactive materials as measurement standards to perform quality control on activity meters; or using a certain activity meter as a standard activity meter, respectively measuring the same medical radioactive material through the standard activity meter and the activity meter to be measured, to achieve quality control of the activity meter to be measured; or using the activity meter as a measurement standard to perform activity value measurement on medical radioactive materials.

Claims

1. A multi-mode activity measurement system based on automatic placement of medical radioactive materials, comprising a measuring device and a software control unit, characterized in that: The measuring device comprises a lead glass enclosure (1) provided with lead glass windows, a lead shielding room (2) arranged inside the lead glass enclosure (1), a plurality of limit points for placing ionization chambers, and a gantry structure three-axis linkage mechanism; The lead shielding room (2) comprises a lead room body (10) with a storage space therein and an openable lead room cover (13) arranged above the lead room body (10); a plurality of hole points for placing a storage cylinder (12) are arranged in the storage space of the lead room body (10); the storage cylinder (12) is used to store medical radioactive substances; The three-axis linkage mechanism of the gantry structure is provided with a manipulator (9) for grabbing the storage tube (12), and the software control unit controls the manipulator (9) to perform high-precision movement in the XYZ axis directions to complete the movement, placement and positioning of the storage tube (12) between the lead shielding room (2) and the ionization chamber; The software control unit is used to control the measuring device and is linked to the state of the lead glass window on the lead glass fence (1). When the lead glass window is open, the software control unit is prohibited from operating. The software control unit can only operate after the lead glass window is manually closed.

2. The multi-mode activity measurement system based on automatic placement of medical radioactive materials according to claim 1 is characterized in that: The gantry structure three-axis linkage mechanism comprises an X-axis precision linear guide rail (4), a right Y-axis precision linear guide rail (3), a left Y-axis precision linear guide rail (6) and a Z-axis precision linear guide rail (5); The right Y-axis precision linear guide (3) and the left Y-axis precision linear guide (6) are parallel to each other and are respectively arranged on both sides of the lead shielding room (2) and the ionization room; one end of the X-axis precision linear guide (4) is slidably connected to the right Y-axis precision linear guide (3), and the other end is slidably connected to the left Y-axis precision linear guide (6); the Z-axis precision linear guide (5) is perpendicular to the X-axis precision linear guide (4) and the right Y-axis precision linear guide (3), and is slidably connected to the X-axis precision linear guide (4) through a connecting component (19); the manipulator (9) is slidably connected to the Z-axis precision linear guide (5); The software control unit controls the X-axis precision linear guide rail (4) to move in the Y-axis direction, controls the Z-axis precision linear guide rail (5) to move in the X-axis direction, and controls the manipulator (9) to move in the Z-axis direction.

3. The multi-mode activity measurement system based on automatic placement of medical radioactive materials according to claim 1 is characterized in that: Two 4πγ ionization chambers are placed at the ionization chamber limit points and are numbered as ionization chamber No. 1 (7) and ionization chamber No. 2 (8) respectively.

4. The multi-mode activity measurement system based on automatic placement of medical radioactive materials according to claim 1 is characterized in that: The hole points for placing the storage cylinder (12) are in an m×n array, and the inner wall is provided with an isolation layer (11) made of plastic; the lead chamber cover (13) is opened and closed by a stepper motor (14); the storage cylinder (12) is made of synthetic plastic, and a portion (15) for being grasped by a robot is provided on the top, and a sealing cover (16) is provided on the bottom.

5. The first mode activity measurement method using the multi-mode activity measurement system based on automatic placement of medical radioactive materials according to claim 1 is characterized in that: Using medical radioactive materials as measurement standards, the steps for quality control of the activity meter are as follows: Step 501: Medical radioactive materials including multiple nuclides should be selected as measurement standards, put into storage cylinders, and then put into holes in the lead shielding room, and the lead room cover is closed; each medical radioactive material is numbered according to the corresponding hole points, and a standard source library is established; Step 502: placing the 4πγ ionization chamber of the activity meter to be tested at the limit position of the ionization chamber; operating the manipulator to align the center coordinates of the ionization chamber, reading the real-time coordinates of the manipulator and saving them; Step 503: setting the nuclide setting conditions of the activity meter to be measured, closing the lead glass window, and opening the lead chamber cover; Step 504: According to the hole point number and the number of the ionization chamber to be tested, the storage cylinder containing the required nuclide is grabbed by the manipulator and moved from the lead shielding room to above the center point of the selected ionization chamber; Step 505: Starting from the wellhead of the selected ionization chamber, the storage tube is controlled by the manipulator to move downward to change the axial position of the medical radioactive material in the ionization chamber; the axial response of each position is realized by formula (1), and the axial response F z The measured value A of the activity meter at each position during axial movement after deducting the background Z Compared with the standard value of medical radioactive materials A s Divide to get: F z =A Z / A s (1) Step 506: Position the medical radioactive material at the geometric position with the maximum axial response; control the storage tube to move radially by the manipulator, and the radial response of each position is realized by formula (2), and the radial response F a The measured value A of the activity meter at each position after deducting the background during radial movement a Compared with the standard value of medical radioactive materials A s Divide to get: F a =A a / A s (2) Step 507: Control the storage tube to be positioned at the optimal geometric position with the maximum axial response and the minimum radial response, calculate the relative inherent error E of the activity meter to be measured under the setting conditions of the nuclide of the medical radioactive material according to formula (3), complete the calibration evaluation of the activity meter to be measured under the nuclide, and realize its quality control: The calibration coefficient of the activity meter to be measured for the corresponding nuclide is k = A s / A, A is the measured value of the activity meter after deducting the background.

6. The activity measurement method according to claim 5, characterized in that: If the second ionization chamber is to be measured, the measured storage tube is moved from the measured ionization chamber to the second ionization chamber, and steps 505 to 507 are repeated to obtain the evaluation result of the second ionization chamber, and so on; If the first ionization chamber that has been measured needs to be measured under another nuclide setting condition, the measured storage tube is moved from the measured ionization chamber to the lead shielding room, and then the hole point corresponding to the storage tube number is placed, and then the medical radioactive material of the second nuclide is selected, and steps 504 to 507 are repeated to complete the calibration evaluation of the first ionization chamber under the second nuclide, and so on; If the measurement work is completed, the measured medical radioactive material will be moved from the measured ionization chamber to the lead shielding room, and then placed in the hole corresponding to the number of its storage tube, and the lead chamber cover will be closed to end the measurement.

7. A second mode activity measurement method using the multi-mode activity measurement system based on automatic placement of medical radioactive materials as claimed in claim 3, characterized in that: Select an activity meter as a standard activity meter, and use the standard activity meter and the activity meter to measure the same medical radioactive material. The steps to achieve quality control of the activity meter to be measured are as follows: Step 701: Put the medical radioactive materials including various nuclides into storage tubes respectively, and then put them into the hole points of the lead shielding room, and close the lead room cover; number each medical radioactive material according to the corresponding hole points, and establish a standard source library; Step 702: Place the 4πγ ionization chamber of the standard activity meter at the No. 1 ionization chamber point, and place the 4πγ ionization chamber of the activity meter to be tested at the No. 2 ionization chamber point; operate the manipulator to align the center coordinates of the two ionization chambers, read the real-time coordinates of the manipulator and save them; Step 703: set the nuclide setting conditions of the standard activity meter and the activity meter to be tested, close the lead glass window, and open the lead chamber cover; Step 704: according to the hole point number and the number of the No. 1 ionization chamber, grab the storage cylinder of the medical radioactive material containing the required nuclide through the manipulator, and move it from the lead shielding room to above the center point of the No. 1 ionization chamber; Step 705: Starting from the wellhead of No. 1 ionization chamber, the storage tube is controlled by the manipulator to move downward to change the axial position of the medical radioactive material in the ionization chamber; the measured value of the activity meter at each position after deducting the background is measured, and the maximum value of the measured value is set as the maximum axial response value; Step 706: Position the medical radioactive material at the geometric position with the maximum axial response, and control the storage tube to move radially by the manipulator; measure the measured value of the activity meter at each position after deducting the background, and set the minimum value of the measured value as the minimum radial response value; Step 707: Control the storage tube to be positioned at the optimal geometric position of the maximum axial response and the minimum radial response of the No. 1 ionization chamber, and the measured value of the activity meter at this position after deducting the background is the standard value A. s ; Step 708: Move the measured storage tube from ionization chamber No. 1 to ionization chamber No. 2, and use the A measured by the standard activity meter s As standard values, the axial response and radial response of ionization chamber No. 2 were measured; Step 709: Control the storage tube to be positioned at the optimal geometric position of the maximum axial response and the minimum radial response of the No. 2 ionization chamber, calculate the relative inherent error E of the activity meter to be measured under the current nuclide setting conditions of the radioactive material; complete the calibration evaluation of the activity meter to be measured under the nuclide to achieve its quality control.

8. The activity measurement method according to claim 7, characterized in that: If the activity meter to be measured is to be measured under another nuclide setting condition, the measured storage tube is moved from the No. 2 ionization chamber to the lead shielding room, and then the hole corresponding to the storage tube number is placed, and then the medical radioactive material of the second nuclide is selected, and steps 704 to 709 are repeated to complete the calibration evaluation of the activity meter to be measured under the second nuclide, and so on; If the measurement work is completed, the measured radioactive material will be moved from the measured ionization chamber to the lead shielding room, and then placed in the hole corresponding to the number of its storage tube, and the lead chamber cover will be closed to end the measurement.

9. A method for measuring activity in a third mode using the multi-mode activity measurement system based on automatic placement and placement of medical radioactive materials as claimed in claim 3, characterized in that: The steps for measuring the activity value of medical radioactive materials using an activity meter as a measurement standard are as follows: Step 801: Place the 4πγ ionization chamber of the activity meter used as the measurement standard at the position of the No. 1 ionization chamber or the No. 2 ionization chamber, and use the 4πγ ionization chamber as the standard ionization chamber; put a batch of medical radioactive materials to be tested into the storage tubes respectively, and then put them into the holes of the lead shielding room respectively, and close the lead room cover; number each medical radioactive material according to the corresponding hole position, and establish a source library; Step 802: operate the manipulator to align the center coordinates of the standard ionization chamber, and read and save the real-time coordinates of the manipulator; Step 803: set the nuclide setting conditions of the activity meter as the measurement standard, close the lead glass window, and open the lead chamber cover; Step 804: according to the hole point number and the standard ionization chamber number, grab the storage tube containing the medical radioactive material to be measured by the manipulator, and move it from the lead shielding room to the top of the center point of the selected ionization chamber; Step 805: According to the calibration evaluation of the activity meter, two different operations are selected: 1) If the activity meter has a calibration coefficient k for the corresponding nuclide of the medical radioactive material to be measured h , and the optimal geometric position for activity measurement in the ionization chamber has been calibrated, the storage tube is positioned to the optimal geometric position in the ionization chamber by the manipulator, and the measured value A of the activity meter after deducting the background is measured; then the activity calibration value A of the medical radioactive material to be measured k Formula (4) is used to obtain the value of medical radioactive substances; A k =k h ×A (4) 2) If the activity meter does not measure the calibration coefficient k of the corresponding nuclide of the medical radioactive material to be measured h , or if the optimal geometric position for activity measurement in the ionization chamber is not calibrated, the axial response and radial response of the ionization chamber must be measured; the storage tube is controlled by a manipulator to be positioned at the optimal geometric position for the maximum axial response and the minimum radial response of the ionization chamber, and the measurement value of the activity meter at this position after deducting the background is the activity calibration value of the medical radioactive substance to be measured, thereby achieving the fixed value of the medical radioactive substance.

10. The activity measurement method according to claim 9, characterized in that: If other medical radioactive materials need to be measured, the measured storage tube is moved from the ionization chamber to the lead shielding chamber, and then placed in the hole corresponding to the storage tube number, and then the second medical radioactive material is selected, and steps 804 to 805 are repeated to complete the measurement and setting of the second medical radioactive material, and so on; If the measurement work is completed, the measured medical radioactive material will be moved from the ionization chamber to the lead shielding room, and then placed in the hole corresponding to the number of its storage tube, and the lead chamber cover will be closed to end the measurement.

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