Dynamic measuring device for activity of medical radioactive waste liquid

Abstract

The utility model relates to a dynamic measuring device for activity of medical radioactive waste liquid, in particular to the field of radiation monitoring, which comprises a sample chamber and a detector. The sample chamber is provided with a liquid level detection device, an overflow detection device, a sample feeding / discharging pump and cleaning equipment; the sample chamber comprises a protection cavity and a Marinin cup-shaped sample box; the detector is positioned above the Marinin cup-shaped sample box; the liquid level detection device comprises first liquid level detection equipment arranged at the bottom end of the sample chamber and movable second liquid level detection equipment; the overflow detection device is used for detecting whether materials in the sample chamber overflow the sample chamber; the medical radioactive waste liquid decay pool is connected with the sample chamber through the sample injection / discharge pump; and a control valve is arranged between the sample feeding / discharging pump and the sample chamber. The measuring device provided by the utility model can accurately measure the activity of radionuclides in the waste liquid, and can realize that the measuring result can be traced to the national social public measurement standard through accurate measurement, so that the reliability is guaranteed.

Description

Technical Field

[0001] The utility model relates to the field of radiation monitoring, in particular to a dynamic measuring device for the activity of medical radioactive waste liquid. Background Art

[0002] Medical radioactive liquid waste refers to liquid containing radionuclides generated in open radiation workplaces such as nuclear medicine, medical and biological laboratories. It mainly comes from three sources:

[0003] (1) Excreta of patients waiting for treatment or in hospital after taking radioactive drugs during nuclear medicine diagnosis and treatment;

[0004] (2) Decontamination washing liquid produced by cleaning;

[0005] (3) Radioactive wastewater discharged from the preparation of medical marker compounds and the disposal of excess doses of radioactive isotopes.

[0006] There are currently three main methods for measuring the activity of medical radioactive waste:

[0007] (1) Immersed real-time online monitoring, that is, the detector is immersed in the decay pool for measurement. A Geiger counter or scintillator detector is usually used. In order to prevent the medical radioactive waste from corroding the detector, the detector surface is often covered with corrosion-resistant protective materials.

[0008] (2) Post-sampling laboratory analysis, i.e. sampling at the site of the medical radioactive waste decay pool and then sending the sample to a qualified laboratory for measurement and analysis;

[0009] (3) Physical decay method, that is, after the medical radioactive waste liquid is stored in a decay pool, its activity decays with time according to the negative exponential law based on the half-life of the main nuclides in it. The radioactive waste liquid containing nuclides with a half-life greater than 24 hours is temporarily stored for more than 10 times the longest half-life (the temporary storage time of iodine-131 nuclides is more than 180 days). After the monitoring results are approved by the review and supervision department, they are discharged into the environment in accordance with the provisions of 8.6.2 of GB18871.

[0010] However, since it is impossible to use standard materials with the same geometry, matrix and volume as the decay cell for calibration in immersion real-time online monitoring, this method can only qualitatively indicate the strength of the radioactive activity in the waste liquid, but cannot accurately quantify the activity of the radioactive nuclides. Furthermore, if the detector fails, it may not be able to be replaced in a short time, and there is a risk of monitoring gaps.

[0011] Alternatively, the on-site sampling method is used and then sent to the laboratory for analysis. However, a large amount of decay will occur during the transportation of the samples to the laboratory for analysis and during the long sample preparation process, resulting in the final measurement result being far lower than the actual activity, which is not suitable for 18 F and99m Activity measurement of short half-life nuclides such as Tc, 131 Although the half-life of I is relatively long, it is only 8 days. On the other hand, the main radionuclides in current medical radioactive waste are 131 I, with volatile characteristics, according to the measurement method specified in GB18466-2005, using EJ / T900-1994 "Determination of total β radioactivity in water by evaporation method", will result in 131 I is completely volatilized during the laboratory pretreatment of total α and total β samples, so the results are far lower than the actual values.

[0012] In summary, the current detection of activity of medical waste liquid still has the defects of poor activity detection accuracy and inability to effectively measure. Utility Model Content

[0013] In view of the problems existing in the prior art, the purpose of the present invention is to provide a dynamic measurement device for the activity of medical radioactive waste liquid, so as to solve the defects of the current detection of medical waste liquid activity, such as poor activity detection accuracy and inability to effectively measure.

[0014] To achieve this purpose, the present invention adopts the following technical solutions:

[0015] The utility model provides a dynamic measuring device for the activity of medical radioactive waste liquid, the dynamic measuring device comprising:

[0016] sample chamber and detector;

[0017] The sample chamber is equipped with a liquid level detection device, an overflow detection device, a sample injection / discharge pump and a cleaning device;

[0018] The sample chamber includes a protective cavity and a Marlin cup-shaped sample box;

[0019] The detector is located above the Marin cup-shaped sample box;

[0020] The liquid level detection device includes a first liquid level detection device arranged at the bottom end of the sample chamber and a movable second liquid level detection device;

[0021] The overflow detection device is used to detect whether the material in the sample chamber overflows the sample chamber;

[0022] The medical radioactive waste liquid decay pool is connected to the sample chamber via the sample injection / discharge pump;

[0023] A control valve is provided between the sample injection / discharge pump and the sample chamber.

[0024] The measuring device provided by the present utility model can accurately measure the activity of radioactive nuclides in waste liquid, and enables the device to achieve traceability of measurement results to national social public measurement standards through accurate measurement, thereby ensuring reliability. At the same time, in order to reduce transportation risks and improve the accuracy of the activity of short-lived nuclides in waste liquid, a dynamic sampling and cleaning function is added, and multiple continuous sampling and measurements can be completed on site, greatly improving work efficiency and result accuracy.

[0025] As a preferred technical solution of the present invention, the detector includes a scintillator detector and a multi-channel analyzer.

[0026] As a preferred technical solution of the present utility model, the Marin cup-shaped sample box comprises: a convex sample cover and a concave sample box;

[0027] The convex sample cover and the concave sample box are connected by a locking structure;

[0028] The convex portion of the convex sample cover extends into the concave area of ​​the concave sample box;

[0029] The length of the convex portion is less than the depth of the concave region;

[0030] The width of the convex portion is smaller than the width of the concave region.

[0031] As a preferred technical solution of the present utility model, the cleaning device includes a washing liquid feeding end and a washing liquid pump connected in sequence;

[0032] The washing liquid pump is connected to the sample chamber through a one-way valve.

[0033] As a preferred technical solution of the present utility model, the dynamic measurement device further includes a control center;

[0034] The control center is connected to the liquid level detection device, the overflow detection device, the sample injection / discharge pump and the cleaning equipment respectively.

[0035] As a preferred technical solution of the present invention, the dynamic measurement device also includes a power supply device.

[0036] As a preferred technical solution of the present utility model, the power supply device includes a DC power supply device and / or a storage power supply device;

[0037] The power storage and power supply device is equipped with a power display module and / or a charging module.

[0038] As a preferred technical solution of the present invention, the control center of the dynamic measurement device is configured with a display module and / or a wireless module.

[0039] As a preferred technical solution of the present utility model, the display module includes an embedded display module or an external display module;

[0040] The display module is connected to the control center via a cable;

[0041] The wireless module is connected to the wireless display module / or the wireless control module through wireless communication.

[0042] As a preferred technical solution of the present invention, the dynamic measurement device is further configured with a working status indication module and / or an emergency stop module.

[0043] Compared with the existing technical solutions, the present invention has the following beneficial effects:

[0044] (1) By configuring a high-sensitivity liquid level sensor, the sampling of medical radioactive waste liquid on site can be automated. After the measurement, the sample can be arranged without disassembly, which greatly shortens the time personnel are exposed to radiation and reduces the risk of radiation dose. At the same time, the efficiency of analysis and measurement is improved. At the same time, the traceability of the radioactive activity value of the nuclides in the waste liquid is achieved, and the result deviation is less than 1.5%.

[0045] (2) A cleaning nozzle is designed on the top of the sample box, which can be used to clean the sample box without disassembly after the measurement is completed. The cleaning liquid can be directly discharged into the decay pool on site without the burden of subsequent treatment of radioactive cleaning waste liquid. At the same time, it can reduce the background interference of different measurement results during continuous operation, extend the service life of the sample box, and achieve a cleaning efficiency of more than 85%.

[0046] (3) The "probe on top and sample below" structure reduces the impact of environmental radiation while reducing the probability of collision damage to the probe surface and reducing the shielding material. The environmental radiation shielding rate reaches more than 84%.

[0047] (4) The measuring device uses a locking structure to connect the convex sample cover and the concave sample box, which can ensure that the cover can be easily tightened when the box is filled with liquid samples, avoiding the risk of jamming and leakage of radioactive waste liquid due to misalignment caused by buoyancy. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a schematic diagram of a dynamic measurement device for the activity of medical radioactive waste liquid provided by an embodiment of the present utility model;

[0049] Figure 2 This is a schematic diagram of a convex sample cover provided by an embodiment of the present utility model;

[0050] Figure 3 It is a schematic diagram of a concave sample box provided by an embodiment of the present utility model.

[0051] In the figure: 1 - sample chamber, 1.1 - Marin cup-shaped sample box, 1.1.1 - convex sample cover, 1.1.2 - convex portion, 1.1.3 - locking structure, 1.1.4 - concave sample box, 1.1.5 - concave area, 1.2 - second liquid level detection device, 1.3 - first liquid level detection device, 1.4 - overflow detection device, 2 - detector, 3 - control valve, 4 - sample injection / discharge pump, 5.1 - washing liquid pump, 5.2 - one-way valve, 6 - medical radioactive waste liquid decay pool, 7 - washing liquid inlet port, 8.1 - computer, 8.2 - relay;

[0052] The dotted lines in the figure are control connections.

[0053] The following is a further detailed description of the present invention. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims. DETAILED DESCRIPTION

[0054] In order to better illustrate the present invention and facilitate understanding of the technical solution of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0055] This embodiment provides a dynamic measurement device for the activity of medical radioactive waste liquid. Figure 1 As shown, the dynamic measurement device includes:

[0056] Sample chamber 1 and detector 2;

[0057] The sample chamber 1 is equipped with a liquid level detection device, an overflow detection device 1.4, a sample injection / discharge pump 4 and a cleaning device;

[0058] The sample chamber 1 includes a protective cavity and a Marlin cup-shaped sample box 1.1;

[0059] The detector 2 is located above the Marin cup-shaped sample box 1.1;

[0060] The liquid level detection device comprises a first liquid level detection device 1.3 arranged at the bottom end of the sample chamber 1 and a movable second liquid level detection device 1.2;

[0061] The overflow detection device 1.4 is used to detect whether the material in the sample chamber 1 overflows the sample chamber 1;

[0062] The medical radioactive waste liquid decay pool 6 is connected to the sample chamber 1 via the sample injection / discharge pump 4;

[0063] A control valve 3 is provided between the sample injection / discharge pump 4 and the sample chamber 1 .

[0064] In this embodiment, the first liquid level detection device 1.3 is used to monitor whether the collected waste liquid has been completely drained. The second liquid level detection device 1.2 is used to monitor whether the collected waste liquid has reached a set volume. It can be mobile, further meeting the sample volume requirements for different radioactive waste liquid detections. The overflow detection device 1.4 is used to prevent failure of the second liquid level detection device 1.2. When the second liquid level detection device 1.2 fails, the sample injection / discharge pump 4 stops extracting waste liquid when the liquid level reaches this level, thereby preventing overflow.

[0065] The detector 2 includes a scintillator detector and a multi-channel analyzer.

[0066] Wherein, the Marin cup sample box includes: a convex sample cover 1.1.1 and a concave sample box 1.1.4, such as Figure 2 and Figure 3 shown.

[0067] The convex sample cover 1.1.1 and the concave sample box 1.1.4 are connected by a locking structure 1.1.3; exemplary locking structures 1.1.3 include thread locking or snap locking, which are commonly used locking structures of covers and bottles.

[0068] The convex portion 1.1.2 of the convex sample cover 1.1.1 extends into the concave area 1.1.5 of the concave sample box 1.1.4.

[0069] In order to ensure smooth drainage after testing and washing, the concave sample box 1.1.4 adopts a concave curved surface design to ensure that the liquid is fully drained.

[0070] Wherein, the length of the convex portion 1.1.2 is less than the depth of the concave area 1.1.5.

[0071] Wherein, the width of the convex portion 1.1.2 is less than the width of the concave area 1.1.5.

[0072] Among them, the relevant shapes of the convex sample cover and the concave sample box, such as the cover shape, box body shape, convex part shape, and concave area shape, can be designed according to actual needs.

[0073] The cleaning device comprises a washing liquid inlet 7 and a washing liquid pump 5.1 connected in sequence; the washing liquid pump 5.1 is connected to the sample chamber 1 through a one-way valve 5.2.

[0074] The dynamic measurement device further comprises a control center, which is connected to the liquid level detection device, the overflow detection device 1.4, the sample injection / discharge pump 4 and the cleaning device respectively.

[0075] In this embodiment, the control center includes a computer 8.1, a PLC controller or an ECU, or other commonly used industrial control centers.

[0076] Wherein, the dynamic measurement device also includes a power supply device; the power supply device includes a DC power supply device and / or a storage power supply device; the storage power supply device is equipped with a power display module and / or a charging module.

[0077] The control center of the dynamic measurement device is equipped with a display module and / or a wireless module; the display module includes an embedded display module or an external display module; and the display module is connected to the control center via a cable.

[0078] In this embodiment, the display module is used to display the test results and control the operation of the device. It can be integrated with the control center. Furthermore, through the wireless module, wireless remote operation can be used to realize the control of the test process and the monitoring of the detection device. It can also be connected to the intelligent control system to realize intelligent control of the device, such as joint control with the discharge end to realize the linkage between discharge and detection.

[0079] Wherein, the dynamic measurement device is further configured with a working status indication module and / or an emergency stop module.

[0080] In this embodiment, the working status indicator module can be configured to intuitively confirm whether the measuring device is operating properly. The emergency stop module can realize the emergency stop of the device and the simultaneous linkage stop of liquid discharge when a detection error or an operation error occurs.

[0081] Exemplarily, the present invention provides a control method for the aforementioned dynamic measurement device, the control method comprising:

[0082] S1. Start self-test and collect background spectrum;

[0083] S2. Perform background spectrum verification and energy calibration;

[0084] S3. Draw the sample to the preset liquid level, complete the test and analyze the data to obtain the activity.

[0085] The power-on self-test includes: powering on to detect whether there is residual liquid in the sample chamber 1, if so, cleaning and draining the liquid, otherwise collecting background spectrum.

[0086] Wherein, the background spectrum verification includes identifying characteristic energy peaks and / or counting anomaly verification.

[0087] Wherein, the identification characteristic energy peak includes: if the background spectrum is not identified 40 K or 138 The characteristic energy peak of La is detected, and the background measurement time is extended until the 40 K or 138 Energy calibration is performed after the characteristic energy peak of La.

[0088] The counting abnormality verification includes cleaning at least twice and collecting the background spectrum until the counting is normal if there is counting abnormality in the obtained background spectrum.

[0089] The counting anomaly includes: the full spectrum counting rate is greater than 1.3 times of the initial background counting rate and / or the spectrum contains 40 K or 138 Other energy peaks besides the characteristic energy peak of La. ;

[0090] Wherein, the energy scale includes: marking 40 The characteristic energy peak of K is 1460keV and / or the isotopic composition of the marker detector 138 The characteristic energy peak of La is 1435.8 keV.

[0091] After the detection is completed, the sample chamber 1 is drained and cleaned at least twice.

[0092] Among them, if the characteristic energy peak of the medical nuclide to be measured appears in the detector measurement spectrum after the cleaning is completed or the spectrum count rate is greater than the background spectrum count rate, cleaning is performed again until the characteristic energy peak of the medical nuclide to be measured disappears or the increase in the full spectrum count rate is ≤30% of the background spectrum count rate (the background spectrum count rate is the count rate obtained by collecting the background spectrum after the spectrum is stabilized), and the cleaning is completed.

[0093] Wherein, if the sample chamber 1 is detected after the cleaning is completed 131 The activity of I is recorded 131 The activity of I is removed when measuring again 131 The decay value of I.

[0094] Furthermore, in order to illustrate the measurement effect that can be achieved by the dynamic measurement device provided by the present invention, the following actual examples are used for illustrative purposes, as follows:

[0095] Example 1

[0096] This embodiment provides a dynamic measurement device for the activity of medical radioactive waste liquid, comprising the following:

[0097] Sample chamber 1 and detector 2;

[0098] The sample chamber 1 is equipped with a liquid level detection device, an overflow detection device 1.4, a sample injection / discharge pump 4 and a cleaning device;

[0099] The sample chamber 1 includes a protective cavity and a Marlin cup-shaped sample box 1.1;

[0100] The detector 2 is located above the Marin cup-shaped sample box 1.1;

[0101] The liquid level detection device comprises a first liquid level detection device 1.3 arranged at the bottom end of the sample chamber 1 and a movable second liquid level detection device 1.2;

[0102] The overflow detection device 1.4 is used to detect whether the material in the sample chamber 1 overflows the sample chamber 1;

[0103] The medical radioactive waste liquid decay pool 6 is connected to the sample chamber 1 via the sample injection / discharge pump 4;

[0104] A control valve 3 is provided between the sample injection / discharge pump 4 and the sample chamber 1 .

[0105] The detector 2 includes a scintillator detector and a multi-channel analyzer.

[0106] The Marin cup-shaped sample box comprises: a convex sample cover 1.1.1 and a concave sample box 1.1.4; the convex sample cover 1.1.1 and the concave sample box 1.1.4 are connected by a locking structure 1.1.3, which is a threaded locking structure.

[0107] In which, the convex portion 1.1.2 of the convex sample cover 1.1.1 extends into the concave area 1.1.5 of the concave sample box 1.1.4; specifically, the convex portion 1.1.2 and the concave area 1.1.5 are both columnar structures, the length of the convex portion 1.1.2 (100mm) is less than the depth of the concave area 1.1.5 (161mm); the width of the convex portion 1.1.2 (50mm) is less than the width of the concave area 1.1.5 (115mm).

[0108] The cleaning device comprises a washing liquid inlet port 7 and a washing liquid pump 5.1 which are connected in sequence; the washing liquid pump 5.1 is connected to the sample chamber 1 via a one-way valve 5.2.

[0109] The dynamic measurement device also includes a control center; the control center is connected to the liquid level detection device, overflow detection device 1.4, sample injection / discharge pump 4, and cleaning equipment. The control center of the dynamic measurement device is equipped with a display module; the display module is an embedded display module, which is connected to the control center via a cable. If the control center is equipped with an embedded display module, it is implemented by cooperating with a computer 8.1 and a relay 8.2.

[0110] The dynamic measurement device further includes a power supply device, and the power supply device includes a direct current power supply device.

[0111] The dynamic measurement device is further configured with a working status indication module and / or an emergency stop module.

[0112] The specific usage process is as follows:

[0113] 1. Move a radioactive waste liquid activity measurement device equipped with a LaBr3(Ce) detector (a scintillator detector) to the side of a hospital decay pool, start preheating, and begin spectrum stabilization. After completion, measure and save the background spectrum.

[0114] 2. Place one end of the hose into the waste liquid decay pool and connect the other end to the sampling interface of the device. Then click the peristaltic pump start command to start pumping waste liquid into the sample box. When the liquid level reaches 1L, the peristaltic pump automatically stops sampling.

[0115] 3. Set the detector multi-channel parameters, enter the measurement time, high voltage and other parameters, click the start measurement command, and the detector part of the device will start spectrum measurement;

[0116] 4. After the measurement is completed, save the measured spectrum and then analyze the peak positions in the spectrum. The results are shown in Table 1 below.

[0117] Table 1

[0118] Nuclide Energy (keV) Branching ratio (%) <![CDATA[ROI count rate (s -1 )]]> Activity (Bq / L) <![CDATA[ 131 I]]> 284.31 6.1 19.1 47758 <![CDATA[ 131 I]]> 364.49 81.5 195.53 47640 <![CDATA[ 131 I]]> 636.99 7.16 7.92 47696 <![CDATA[ 18 F]]> 511 1.935 183.45 18320 <![CDATA[ 99m Tc]]> 140.51 89 496.57 41540

[0119] 5. To discharge the waste liquid, the peristaltic pump starts to rotate in the reverse direction to extract the waste liquid in the sample box into the decay tank. When the liquid level drops to the low level, the sensor corresponding to the low level detection device automatically sends a command and the peristaltic pump stops running.

[0120] 6. Connect one end of the cleaning hose to a bucket of clean water and the other end to the rinse inlet on the top of the sample box. Then click the cleaning command. The cleaning pump starts, and clean water enters the sample box through the three nozzles installed on the top of the sample box to clean the sample box. At the same time, the peristaltic pump automatically starts the drainage function. Each cleaning lasts for 15 seconds. After two consecutive cleanings, the cleaning stops.

[0121] 7. Click Spectrum Measurement again and check the cleaning status through the spectrum. If the background count rate is higher than the background count rate in step 1, click the Cleaning command again to perform cleaning.

[0122] 8. Repeat steps 6 and 7 until the increase in the full spectrum count rate is no more than 30% of the background spectrum count rate obtained in step 1. The measurement is complete.

[0123] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details of the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0124] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0125] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A dynamic measuring device for the activity of medical radioactive waste liquid, characterized in that: The dynamic measurement device comprises: sample chamber and detector; The sample chamber is equipped with a liquid level detection device, an overflow detection device, a sample injection / discharge pump and a cleaning device; The sample chamber includes a protective cavity and a Marlin cup-shaped sample box; The detector is located above the Marin cup-shaped sample box; The liquid level detection device includes a first liquid level detection device arranged at the bottom end of the sample chamber and a movable second liquid level detection device; The overflow detection device is used to detect whether the material in the sample chamber overflows the sample chamber; The medical radioactive waste liquid decay pool is connected to the sample chamber via the sample injection / discharge pump; A control valve is provided between the sample injection / discharge pump and the sample chamber.

2. The dynamic measurement device according to claim 1, wherein: The detector includes a scintillator detector and a multi-channel analyzer.

3. The dynamic measurement device according to claim 1, wherein The Marin cup-shaped sample box comprises: a convex sample cover and a concave sample box; The convex sample cover and the concave sample box are connected by a locking structure; The convex portion of the convex sample cover extends into the concave area of ​​the concave sample box; The length of the convex portion is less than the depth of the concave region; The width of the convex portion is smaller than the width of the concave region.

4. The dynamic measurement device according to claim 1, wherein: The cleaning equipment includes a washing liquid feeding end and a washing liquid pump connected in sequence; The washing liquid pump is connected to the sample chamber through a one-way valve.

5. The dynamic measurement device according to claim 1, wherein: The dynamic measurement device also includes a control center; The control center is connected to the liquid level detection device, the overflow detection device, the sample injection / discharge pump and the cleaning equipment respectively.

6. The dynamic measurement device according to claim 1, wherein: The dynamic measurement device further includes a power supply device.

7. The dynamic measurement device according to claim 6, characterized in that The power supply equipment includes a DC power supply equipment and / or a storage power supply equipment; The power storage and power supply device is equipped with a power display module and / or a charging module.

8. The dynamic measurement device according to claim 5, characterized in that The control center of the dynamic measurement device is configured with a display module and / or a wireless module.

9. The dynamic measurement device according to claim 8, characterized in that The display module includes an embedded display module or an external display module; The display module is connected to the control center via a cable; The wireless module is connected to the wireless display module / or the wireless control module through wireless communication.

10. The dynamic measurement device according to claim 1, wherein: The dynamic measurement device is further configured with a working status indication module and / or an emergency stop module.

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