JP4095055B2 - Method and apparatus for dispensing radioactive liquid - Google Patents

Description

  The present invention relates to a radioactive liquid dispensing method and a dispensing apparatus.

A nuclear medicine diagnostic method for diagnosing diseases and the like by administering a radioactive liquid containing a compound labeled with a radionuclide (RI) into the body and imaging the state in which the labeled compound is collected at a specific location in the body with a dedicated device. Has been developed. In this diagnostic method, a relatively short-lived radionuclides (e.g., as a positron-emitting nuclide, ¹⁵ O 2 minutes, ¹¹ C is 20 minutes, ¹⁸ F has a half-life of 110 minutes) labeled with, ¹⁵ O -Water, ¹¹ C-methionine, ¹⁸ F-FDG (fluorodeoxyglucose) or the like is used as the radioactive liquid.

The radioactive liquid used for such nuclear medicine diagnosis is synthesized by a synthesizer and stored in an original container. Then, when the radioactive liquid is subdivided or administered to a subject, for example, as disclosed in Patent Document 1, the syringe is driven and controlled to dispense a predetermined amount from the original container.
JP 2002-306609 A

  Here, in the conventional method in which the radioactive liquid is simply dispensed from the original container to the dispensing container by the syringe, it may be necessary to dispense a very small amount when the radioactive liquid has a high concentration. However, since there is play in the packing provided at the tip of the syringe piston, the influence of play cannot be ignored when dispensing a very small amount, and accurate dispensing is not always possible. There was a fear.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a radioactive liquid dispensing method and a dispensing apparatus capable of improving the dispensing accuracy of a radioactive liquid.

  The method for dispensing a radioactive liquid according to the present invention is a method for dispensing a radioactive liquid from an original container to a dispensing container using a suction / discharge device. This method involves extracting a part of the radioactive liquid from the original container and storing it in a storage container, diluting the radioactive liquid remaining in the original container, and then dispensing the diluted radioactive liquid into the dispensing container. It is characterized by.

  In this method, a part of the radioactive liquid is extracted from the original container and stored in the storage container, and the radioactive liquid remaining in the original container is diluted. By doing so, the amount of liquid necessary to obtain the same amount of radioactivity can be increased. Therefore, even if there is a possibility that high-precision dispensing with a suction dispenser may be difficult with a very small amount before dilution, the amount of liquid necessary to obtain the same amount of radioactivity will increase, thereby dispensing radioactive liquid. The accuracy is improved.

  At this time, it is preferable that at least a part of the radioactive liquid stored in the storage container is returned to the original container when the radioactive amount of the radioactive liquid in the original container becomes a predetermined value or less. If it does in this way, the radioactive liquid required for dispensing will be replenished and it will become possible to continue dispensing operation.

In addition, the minimum amount of radioactivity extracted from the original container is R _m , the concentration of the radioactive liquid stored in the original container is R _c , the allowable minimum discharge liquid amount of the suction discharger is L _m, and R _m and R _c are When the ratio (R _m / R _c ) of Z is Z, when Z <L _m, it is preferable that a part of the radioactive liquid is extracted from the original container and stored in the storage container. In this way, it is possible to reliably improve the dispensing accuracy when there is a high possibility that high-precision dispensing by the suction / discharge device is difficult.

In addition, the liquid volume L ₂ before dilution of the radioactive liquid left in the original container is the minimum extracted radioactivity quantity R _m , the allowable minimum discharge liquid quantity L _m , the concentration R _{c of} the radioactive liquid, and the radioactive liquid stored in the original container It is preferable that the permissible liquid volume L ₀ or less determined based on the liquid volume L ₁ . If it does in this way, the radioactive liquid of the liquid quantity which can perform highly accurate dispensing by a suction discharge device after dilution can remain in an original container.

  A dispensing apparatus for a radioactive liquid according to the present invention includes an original container for containing a radioactive liquid, a dispensing container for dispensing the radioactive liquid from the original container, and a part of the radioactive liquid extracted from the original container. A storage container for storing the liquid, a suction / discharge device for performing suction and discharge of the radioactive liquid, a dilution liquid supply unit for supplying a dilution liquid for diluting the radioactive liquid, an original container, a dispensing container, and storage And a flow path switching means for switching the flow path between the container, the suction / discharge device, and the diluent supply section.

  In this apparatus, a part of the radioactive liquid is extracted from the original container and stored in the storage container, and the radioactive liquid remaining in the original container can be diluted. Therefore, even if the radioactive liquid before dilution has a high concentration, the amount of liquid necessary for obtaining the same amount of radioactivity can be increased by dilution. As a result, even if there is a possibility that high-precision dispensing with a suction dispenser may be difficult with a very small amount before dilution, the amount of liquid required to obtain the same amount of radioactivity will increase. Improvement is achieved.

  According to the present invention, it is possible to improve the dispensing accuracy of the radioactive liquid.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals are used for the same elements, and duplicate descriptions are omitted.
(First embodiment)

  FIG. 1 is a diagram illustrating a configuration of a radioactive liquid dispensing apparatus 10 according to the present embodiment. As shown in FIG. 1, a dispensing apparatus 10 includes a stock solution vial (stock container) 12 that stores a stock solution of radioactive liquid, and a radiation detector 14 that can accommodate the stock solution vial 12 and can detect radiation. I have. As the radiation detector 14, for example, a cylindrical ionization chamber can be used. Data detected by the radiation detector 14 is sent to a control device 16 to be described later, and the amount of radioactivity in the stock vial 12 is estimated from the detected radiation dose using a radiation dose-activity characteristic curve prepared in advance. Can do.

  The dispensing device 10 includes a weight measuring device 18 and an imaging device 20. The weight measuring instrument 18 can be loaded with the stock solution vial 12 and measures the weight of the radioactive liquid stored in the stock solution vial 12. For example, a load cell or an electronic balance can be used as the weight measuring device 18. The imaging device 20 images the stock solution vial 12 and detects the liquid level. For example, a CCD camera can be used as the imaging device 20. The radiation detector 14 is preferably provided with a slit (not shown) in the axial direction so that the stock solution vial 12 can be easily imaged by the imaging device 20.

  The weight measuring device 18 can detect the amount of radioactive liquid in the stock solution vial 12 from the weight as described above, and the imaging device 20 can detect the radioactive content in the stock solution vial 12 from the volume (liquid surface) as described above. The amount of liquid can be detected. Accordingly, the weight measuring device 18 and the imaging device 20 can each constitute a liquid amount detection device. Note that the liquid amount may be calculated using the data of both the weight measuring device 18 and the imaging device 20, and in this case, both the weight measuring device 18 and the imaging device 20 constitute a liquid amount detection device.

  The dispensing apparatus 10 includes a storage vial (storage container) 22 that is a storage destination of the radioactive liquid, and a storage vial storage unit 24 that stores the storage vial 22. The storage vial storage unit 24 is configured by a well-type radiation shielding wall having an upper end opened.

The dispensing apparatus 10 includes a dispensing syringe (dispensing container) 25 that is a dispensing destination of the radioactive liquid. In addition, the dispensing device 10 includes a syringe (suction / discharge device) 26 used to suck and discharge the radioactive liquid. The syringe 26 includes a cylinder and a piston that slides in the cylinder. A packing made of an elastic body such as rubber is provided at the tip of the piston. Therefore, the radioactive liquid can be sucked and discharged from the tip end by pushing and pulling the piston in the cylinder. In addition, the dispensing apparatus 10 includes a diluent supply unit 28 that supplies a diluent for diluting the radioactive liquid. Examples of the diluent include distilled water and physiological saline. In addition, the dispensing device 10 includes a purge gas supply unit 30 that supplies a purge gas (for example, air or N ₂ gas) for purging the liquid in the pipeline.

  The dispensing device 10 includes a syringe drive device 32 that drives the syringe 26. As the piston is reciprocated by the syringe driving device 32, the radioactive liquid is sucked and discharged.

  The dispensing apparatus 10 further includes a flow path switching device 34 that communicates the stock solution vial 12, the storage vial 22, the dispensing syringe 25, the syringe 26, the diluent supply section 28, and the purge gas supply section 30 to switch the flow path. ing. The flow path switching device 34 includes first to fifth three-way valves 34a, 34b, 34c, 34d, and 34e. One port of the first three-way valve 34 a is connected to the stock solution vial 12 via a tube 36. The other port of the first three-way valve 34 a is connected to the purge gas supply unit 30 via a tube 38. The other port of the first three-way valve 34a is directly connected to the one port of the second three-way valve 34b without any break.

  The other port of the second three-way valve 34 b is connected to the diluent supply unit 28 via the tube 40. The other port of the second three-way valve 34b is directly connected to the one port of the third three-way valve 34c without a break. The other port of the third three-way valve 34 c is connected to the syringe 26. The other port of the third three-way valve 34c is directly connected to the one port of the fourth three-way valve 34d without a break. Another port of the fourth three-way valve 34 d is connected to the dispensing syringe 25 via the tube 43. The other port of the fourth three-way valve 34d is directly connected to the port of the fifth three-way valve 34e without any break.

  The other port of the fifth three-way valve 34e is connected to a quality verification unit (not shown). The other port of the fifth three-way valve 34 e is connected to the storage vial 22 via the tube 42.

  The dispensing apparatus 10 includes a control device 16 that controls the dispensing operation of the radioactive liquid. The control device 16 is connected to the radiation detector 14, the weight measuring device 18, the imaging device 20, the three-way valves 34 a, 34 b, 34 c, 34 d, 34 e, and the syringe drive device 32. Specific control by the control device 16 will be described later. The control device 16 is connected to an input unit 44 for inputting parameters necessary for dispensing.

Next, a method for dispensing a radioactive liquid by the above-described dispensing apparatus 10 will be described with reference to the flowcharts of FIGS. In the present embodiment, a case where ¹⁸ F-FDG (fluorodeoxyglucose) is dispensed as the radioactive liquid will be described.

  First, the dispensing device 10 is set up. Specifically, the stock solution vial 12 is accommodated in the radiation detector 14 and mounted on the weight measuring device 18. The storage vial 22 is stored in the storage vial storage unit 24. Further, the dispensing syringe 25 is set at a predetermined position, and the air filter 27 is attached to the tip. Then, the stock solution vial 12 and a synthesis device (not shown) are connected by a tube 46. In addition, the stock solution vial 12 and the purge gas supply unit 30 are connected to the first three-way valve 34a via tubes 36 and 38, respectively. In addition, the diluent supply unit 28 is connected to the second three-way valve 34b through the tube 40. In addition, the syringe 26 is connected to the third three-way valve 34 c and the piston of the syringe 26 is connected to the syringe driving device 32. Further, the storage vial 22 is connected to the fifth three-way valve 34e via the tube 42. In addition, the dispensing syringe 25 is connected to the fourth three-way valve 34 d via the tube 43.

  In the dispensing device 10, when the above setup is completed, the stock solution of FDG is transported to the stock solution vial 12 from the synthesis device (not shown) via the tube 46 and stored. Next, the control device 16 drives the flow path switching device 34 to connect the purge gas supply unit 30 and the stock solution vial 12. Then, the FDG in the stock solution vial 12 is stirred by blowing a purge gas into the stock solution vial 12. From this state, dispensing of FDG to the dispensing syringe 25 is started.

First, referring to FIG. 1 and FIG. 2, the minimum extraction radioactivity amount R _m (MBq) of FDG is input to the control device 16 via the input unit 44 (step S10). The minimum takeout amount of radioactivity R _m is a value set in each facility, a minimum amount of radioactivity to be removed for the stock solution vial 12 dispensed. Here, the minimum takeout amount of radioactivity _{R m} and 100 (MBq) as an example.

Next, is the ratio Z (= R _m / R _c ) between the minimum extracted radioactivity amount R _m and the FDG concentration R _c stored in the stock solution vial 12 smaller than the allowable minimum discharge liquid amount L _{m of} the syringe 26? It is determined whether or not (step S12). Here, as shown in FIG. 3, the control device 16 controls the radiation detector 14 and the weight measuring device 18 and / or the imaging device 20, so that the inside of the stock solution vial 12 every predetermined time (for example, 10 milliseconds). of measuring the amount of radioactivity R and (MBq) liquid volume L and (ml) of FDG, and calculates the activity concentration _{R c} of FDG (step S40, S42, S44). Therefore, a determination in step S12 by using the calculated activity concentration R _c. Incidentally, the allowable minimum discharge fluid amount L _m is the minimum amount of liquid that can be discharged by sucking in no liquid quantity acceptable accuracy being affected by backlash or the like by the syringe 26. Here, the liquid quantity L radioactivity R of FDG as a specific example in 10000 (MBq) is measured as 10 (ml), activity concentration _{R c} is assumed to be 1000 (MBq / ml). Further, the allowable minimum discharge fluid amount _{L m} 1 and (ml).

When the determination result in step S12 is NO, accurate dispensing can be performed without diluting the FDG. Therefore, the process proceeds to step S32 without performing partial storage or dilution of the FDG. Go into note work. On the other hand, when the determination result in step S12 is YES, the process proceeds to step S14. In the above-described specific example, the ratio Z (= R _m / R _c ) is 0.1 (ml), which is smaller than 1 (ml) of the allowable minimum discharge liquid amount L _m , so that the process proceeds to step S14. Become.

In step S14, an allowable radioactivity concentration R ₀ = R _m / L _m is calculated based on the minimum extracted radioactivity amount R _m and the allowable minimum discharge liquid amount L _m . Then, in step S16, based on the liquid amount _{L 1} and concentration _{R c} of FDG permissible activity concentration _{R 0} and stock vial 12, to calculate the allowable liquid volume _{L 0 = L 1 × R 0} / R c . This allowable liquid volume L ₀ is the maximum liquid volume that can be left in the stock solution vial 12 when part of the FDG is stored in the storage vial 22. When the FDG having the allowable liquid volume L ₀ is diluted to the original liquid volume L ₁ with the diluent, the FDG having the minimum extraction radioactivity R _m can be taken out with the allowable minimum discharge liquid volume L _m of the syringe 26. In one specific example described above, the allowable radioactivity concentration R ₀ is 100 (MBq / ml), and the allowable liquid amount L ₀ is 1 (ml).

Next, the flow control device 34 is driven by the control device 16 to cause the stock solution vial 12 and the syringe 26 to communicate with each other. Next, the syringe 26 is driven by the syringe drive device 32, and suction of FDG is started (step S18). Next, the liquid amount L _{2 of} FDG remaining in the stock solution vial 12 after driving the syringe 26 is acquired, and it is determined whether or not the liquid amount L ₂ is within the allowable error range of the allowable liquid amount L ₀ (step). S20). That is, it is determined whether or not the liquid amount L ₂ is within the allowable liquid volume L ₀ ± α. This allowable error range α can be arbitrarily set, for example, can be set to about 3%.

Then, when the determination result of step S20 is NO, it returns to step S18, the allowable liquid amount L ₀ based on the actual amount of liquid so that the difference is small between the liquid volume L ₂ and syringe drive device 32 and feedback control Thus, the syringe 26 is driven to suck or discharge FDG. This operation is repeated, and when the determination result of step S20 is YES, the process proceeds to the next step S22. By this operation, a predetermined amount L ₁ -L ₀ of FDG is taken out from the stock solution vial 12 to the syringe 26 so that FDG within the permissible error range α of the permissible solution amount L ₀ remains in the stock solution vial 12. In the above-described specific example, 9 (ml) of FDG is taken out from the stock solution vial 12 to the syringe 26 so that FDG within an allowable error range α of 1 (ml) remains in the stock solution vial 12.

  Next, the flow path switching device 34 is driven by the control device 16 to cause the storage vial 22 and the syringe 26 to communicate with each other (step S22). Then, the control device 16 drives the syringe drive device 32 to push back the piston of the syringe 26, and discharges FDG into the storage vial 22 (step S24). Further, the control device 16 drives the flow path switching device 34 to make the purge gas supply unit 30 and the syringe 26 communicate with each other. Next, the purge gas is sucked into the syringe 26 from the purge gas supply unit 30, whereby the FDG remaining in the flow path switching device 34 is sucked into the syringe 26 together with the purge gas. Next, the flow control device 34 is driven by the control device 16 to cause the syringe 26 and the storage vial 26 to communicate with each other. Then, the syringe drive device 32 is driven by the control device 16 to push back the piston of the syringe 26 and discharge the FDG together with the purge gas into the storage vial 22.

As a result, as shown in FIG. 4, the FDG having the allowable liquid amount L ₀ is stored in the stock solution vial 12, and the F ₁ -L ₀ FDG is stored in the storage vial 22. In the above-described specific example, 1 (ml) of FDG is stored in the stock solution vial 12, and 9 (ml) of FDG is stored in the storage vial 22.

Next, the liquid volume 1 = L ₁ -L ₀ of the diluent for diluting the FDG remaining in the stock solution vial 12 is calculated (step S26). Next, the flow control device 34 is driven by the control device 16 to cause the syringe 26 and the diluent supply unit 28 to communicate with each other. Then, the diluted liquid with the liquid volume l calculated in step S26 is sucked into the syringe 26 (step S28). In one specific example described above, 9 (ml) of the diluted solution is sucked into the syringe 26.

  Next, the flow control device 34 is driven by the control device 16 to cause the syringe 26 and the stock solution vial 12 to communicate with each other. And the syringe drive device 32 is driven by the control apparatus 16, the piston of the syringe 26 is pushed back, and the dilution liquid is discharged to the stock solution vial 12 (step S30). Further, the control device 16 drives the flow path switching device 34 to make the purge gas supply unit 30 and the syringe 26 communicate with each other. Next, the purge gas is sucked into the syringe 26 from the purge gas supply unit, whereby the diluent remaining in the flow path switching device 34 is sucked into the syringe 26 together with the purge gas. Next, the flow control device 34 is driven by the control device 16 to cause the syringe 26 and the stock solution vial 12 to communicate with each other. Then, the syringe drive device 32 is driven by the control device 16 to push the piston of the syringe 26 back, and the diluted solution is discharged into the stock solution vial 12 together with the purge gas.

As a result, as shown in FIG. 5, the stock vial 12 is in a state where the diluted FDG of the liquid amount L ₁ is stored. In one specific example described above, 10 (ml) diluted FDG is stored in the stock solution vial 12. The radioactivity concentration at this time is 100 (MBq / ml).

  From this state, the FDG dispensing operation to the dispensing syringe 25 is started (step S32).

First, the flow path switching device 34 is driven by the control device 16 to cause the syringe 26 and the stock solution vial 12 to communicate with each other. Then, a desired amount of FDG is sucked from the stock solution vial 12 into the syringe 26. In the present embodiment, the liquid amount of FDG drawn into the syringe 26 for dispensing is always the allowable minimum discharge liquid amount L _m or more syringes 26.

  Next, the flow control device 34 is driven by the control device 16 to cause the syringe 26 and the dispensing syringe 25 to communicate with each other. And the syringe drive device 32 is driven by the control device 16 to push back the piston of the syringe 26, and the FDG is discharged into the dispensing syringe 25. Thereby, as shown in FIG. 6, a predetermined amount of FDG is dispensed into the dispensing syringe 25. In addition, before discharging FDG from the syringe 26 to the dispensing syringe 25, the diluent may be sucked into the syringe 26 and further diluted in the syringe 26.

  In this manner, the FDG dispensing operation to the dispensing syringe 25 is performed. When such a dispensing operation is repeatedly performed and the amount of radioactivity of FDG stored in the stock solution vial 12 falls below a predetermined amount, for example, as shown in FIG. 7, the amount of radioactivity required to perform the next dispensing operation is reduced. If not, return at least a portion of the FDG that was saved from the storage vial 22 to the stock solution vial 12.

  First, the flow path switching device 34 is driven by the control device 16 to cause the syringe 26 and the storage vial 22 to communicate with each other. Then, a desired amount of FDG is sucked into the syringe 26 from the storage vial 22. Next, the flow control device 34 is driven by the control device 16 to cause the syringe 26 and the stock solution vial 12 to communicate with each other. Then, the syringe drive device 32 is driven by the control device 16 to push back the piston of the syringe 26, and the FDG is discharged into the stock solution vial 12 as shown in FIG. Then, the FDG is diluted in the stock solution vial 12 in the same manner as described above, and the dispensing operation to the dispensing syringe 25 is continued.

  Next, the operation and effect of this embodiment will be described.

  In this embodiment, a part of the FDG is extracted from the stock solution vial 12 and stored in the storage vial 22, and the FDG remaining in the stock solution vial 12 is diluted. Therefore, even if the FDG before dilution has a high concentration, By diluting, the amount of liquid required to obtain the same amount of radioactivity can be increased. Therefore, even if there is a possibility that high-precision dispensing with the syringe 26 may be difficult with a very small amount before dilution, the amount of liquid necessary to obtain the same amount of radioactivity increases, thereby improving the dispensing accuracy. It becomes possible to plan.

In particular, when the ratio Z (= R _m / R _c ) between the minimum extraction radioactivity R _m and the concentration R _{c of} FDG stored in the stock solution vial 12 is smaller than the allowable minimum discharge liquid amount L _{m of the} syringe 26, Since a part of the FDG is extracted from the stock solution vial 12 and stored in the storage vial 22, it is possible to reliably improve the dispensing accuracy when there is a high possibility that high-precision dispensing with the syringe 26 will be difficult. it can. In other cases, the FDG is not diluted in the stock solution vial 12 and the storage vial 22 is not stored, and the dispensing operation is performed as it is, so that the efficiency of the dispensing operation is improved as compared with the case of dilution in all cases. Can be achieved.

In addition, the liquid amount L ₂ before dilution of FDG remaining in the stock solution vial 12 is the minimum extraction radioactivity amount R _m , the allowable minimum discharge liquid amount L _m , the FDG concentration R _c , and the FDG solution stored in the stock solution vial 12. Since the permissible liquid volume L ₀ determined based on the volume L ₁ is set, the liquid volume of FDG that can be dispensed with high accuracy by the syringe 26 after dilution can be left in the stock vial 12.

Further, when the radioactivity amount of the FDG in the stock solution vial 12 falls below a predetermined value, at least a part of the FDG stored in the storage vial 22 can be returned to the stock solution vial 12, so that the FDG required for dispensing Can be replenished and the dispensing operation can be continued.
(Second Embodiment)

  Next, a second embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the same element as above-mentioned 1st Embodiment, and the overlapping description is abbreviate | omitted.

  The configuration of the dispensing apparatus 10 according to the second embodiment is substantially the same as the configuration of the dispensing apparatus 10 according to the first embodiment described above, and the dispensing method is different.

That is, in the first embodiment described above, as shown in FIG. 2, first enter the minimum takeout amount of radioactivity R _m (step S10), and the allowable liquid amount L ₀ to leave the stock vial 12 performs various calculations It has been calculated (step S16). However, since each facility in the allowable minimum discharge amount of liquid minimal extraction radioactivity R _m and the syringe 26 L _m such may not be changed to be set once, each time, the input and various minimum extraction radioactivity R _m There may be no need to perform calculations.

Therefore, in the present embodiment, the relationship between the concentration Rc of the FDG stored in the stock solution vial 12 and the allowable liquid amount L ₀ is _calculated from the minimum extracted radioactivity amount R _m and the allowable minimum discharge liquid amount L _{m of the} syringe 26. calculated, determined in advance of the liquid remaining amount L ₂ leaving the stock solution vial 12 based on this.

Table 1 shows an example of the relationship between the radioactivity concentration R _c , the allowable liquid amount L ₀ , and the remaining liquid amount L ₂ before storing the FDG in the storage vial 22. In the calculation of Table 1, the liquid volume _{L 1} of FDG and 18 (ml), a minimum extraction radioactivity _{R m} is the minimum amount of radioactivity taken out at one time by the syringe 26 and 0.99 (MBq), the allowable minimum discharge fluid amount Calculation is made for a radioactivity concentration R _c of 0 to 3000 (MBq / ml) where L _m is 0.5 (ml) and the maximum extracted radioactivity that is the maximum radioactivity extracted at once by the syringe 26 is 450 (MBq). Went.

As shown in the first and second column of Table 1, when it exceeds 300 (MBq / ml) activity concentration _{R c} is permissible activity concentration _{R 0} in before storing FDG in the storage vial 22, minimum extraction to take out the FDG of a radioactivity _{R m} 150 (MBq), it is seen that below the minimum discharge liquid amount is allowable minimum discharge fluid amount _{L m} 0.5 (ml). Therefore, in this case, it is necessary to store a part of the FDG in the storage vial 22 and dilute the rest. In this case, Ekizanryou _{L 2} of FDG to leave the stock solution vial 12, it is necessary to be below the allowable liquid volume _{L 0,} the relational expression of _{L 0 = L 1 × R 0} / R c, first allowable liquid volume L ₀ is calculated. The permissible liquid amount L ₀ calculated in this way is described in the third column of Table 1.

In the present embodiment, as shown in the fourth column of Table 1, the Ekizanryou _{L 2} is a radioactive concentration _{R c} is 1800 (MBq / ml) or more and 1.5 (ml), radioactive concentration R _c is 900 (MBq / ml) than in 1800 (MBq / ml) until Ekizanryou _{L 2} 3.0 and (ml), activity concentration _{R c} exceeds the 300 (MBq / ml) 900 ( MBq Liquid remaining amount L ₂ is 6.0 (ml) until the radioactive concentration R _c is 300 (MBq / ml) or less, and the remaining liquid amount L ₂ is 18 (ml).

Since the liquid remaining amount L ₂ determined in this way is all below the allowable liquid amount L ₀ as shown in the third and fourth columns of Table 1, it is diluted to the original liquid amount 18 (ml). to, even when taking out the FDG in the minimum extraction radioactivity R _m 150 (MBq), as shown in column 7 of Table 1, the minimum allowable discharge liquid amount L of minimum discharge fluid amount syringe 26 It does not fall below 0.5 (ml) which is _m .

Note that the dilution after the density in the fifth column of Table 1, is radioactivity concentration when diluted with FDG of Ekizanryou L ₂ to the original liquid volume 18 (ml). Further, the maximum discharge liquid amount in the sixth column of Table 1 is a discharge amount required when taking out 450 (MBq) of FDG which is the maximum extraction radioactivity amount.

From the results mentioned above, the density R _c of FDG that is stored in the stock solution vial 12, the relationship between the evacuation liquid amount L _t Keep is retracted in the storage vial 12 shown in Table 2. The dispensing device 10 according to the present embodiment stores a table as shown in Table 2 in the memory of the control device 16 in advance.

  Next, the dispensing method of this embodiment is demonstrated with reference to the flowchart of FIG.9 and FIG.10.

  First, similarly to the first embodiment, the dispensing device 10 is set up. When the above setup is completed, the FDG stock solution is transferred to the stock solution vial 12 from the synthesis device (not shown) via the tube 46 and stored. Next, the control device 16 drives the flow path switching device 34 to connect the purge gas supply unit 30 and the stock solution vial 12. Then, the FDG in the stock solution vial 12 is stirred by blowing a purge gas into the stock solution vial 12. From this state, dispensing of FDG to the dispensing syringe 25 is started.

First, based on the concentration _{R c} of FDG reserved in the stock solution vial 12, to determine evacuation liquid amount _{L t} of storing FDG and is retracted in the storage vial 22 (step S100). Here, as described with reference to FIG. 3, the control device 16 controls the radiation detector 14 and the weight measuring device 18 and / or the imaging device 20 to control the stock solution every predetermined time (for example, 10 milliseconds). the amount of radioactivity FDG in the vial 12 R and (MBq) liquid volume L and (ml) was measured, because it calculates the radioactive concentration _{R c} of FDG (step S40, S42, S44 in FIG. 3), the The calculated radioactivity concentration R _c is used. Also, in the determination of shunting fluid volume L _t, utilizes Table 2 of the table showing the relationship between the evacuation liquid amount L _t and previously determined concentration R _c.

Next, it is determined whether the liquid amount _{L 1} of FDG stock solution vial 12 is less than the retraction liquid amount _{L t} (step S102). If the determination result in step S102 is YES, the process proceeds to step S104 to issue a warning of insufficient liquid amount, and the dispensing operation is terminated. In this case, the FDG in the stock solution vial 12 is diluted by the operator's judgment to increase the liquid volume, and then the dispensing operation is started from the beginning. On the other hand, when the determination result in step S102 is NO, the process proceeds to step S106.

In step S106, it stores the radioactive concentration _{R ts} of FDG of the retracted to the storage vial 22 retract fluid quantity _{L t} as _{R c.} Next, in step S108, the time T _ts when the radioactivity concentration R _ts is stored is stored.

Next, Keep the FDG shunting fluid volume _{L t} determined above step S100, it is retracted to the storage vial 22 (step S110). In the retracted operation, on the basis of the evacuation fluid amount L _t, it may be simply driven control syringe 26 by syringe drive device 32, whereas, as in the first embodiment, the liquid of FDG to leave the stock solution vial 12 calculating a remaining amount L _2, as Ekizanryou L ₂ is within the allowable error range, the feedback control based on the liquid surface, may be driven control syringe 26.

Then, similarly to the first embodiment described above, the FDG in the stock solution vial 12 is diluted to the original liquid amount in Step S112, and the FDG diluted in Step S114 is dispensed into the dispensing syringe 25. In this manner, the FDG dispensing operation to the dispensing syringe 25 is performed. Such dispensing work is repeated, when the liquid amount L of FDG reserved in the stock solution vial 12 is below a predetermined amount, wherein when below the minimum remaining amount L _x is from storage vial 22 to a concentrate vial 12 FDG return work is performed. The minimum residual amount L _x may be set arbitrarily.

  Here, with reference to FIG. 10, the operation of returning the FDG from the storage vial 22 to the stock solution vial 12 will be described.

First, in step S200, whether the liquid amount L of FDG reserved in the stock solution vial 12 is less than the minimum remaining amount L _x is determined. When the determination result of step S200 is YES, the process proceeds to step S202, and the current radioactivity concentration R _tn of FDG stored in the storage vial 22 is calculated based on the following equation.

R _tn = R _ts × exp [−0.693 × ΔT / T _h ]

Here, R _ts is the initial radioactivity concentration of FDG saved in the storage vial 22, and ΔT is the elapsed time from the time T _ts when the radioactivity concentration R _ts is stored to the current time T _tn , T _h is the half-life of FDG (109.8). Note that step S202 can be omitted if the concentration of FDG stored in the storage vial 22 can be directly measured by a radiation detector or the like.

Then, in step S204, based on the calculated current radioactive concentration _{R tn,} calculated on the basis of the return liquid amount _{L r} of FDG back to the stock solution vial 12 to the following equation.

L _r = R _w × L _w / R _tn

Here, R _w is the target stock solution concentration in the stock solution vial 12, and L _w is the target stock solution amount in the stock solution vial 12. For example, _{R w} is _{300 (MBq / ml), L} w is 25 (ml).

Next, in step S206, the return liquid amount _{L r} calculated in step S204 is, whether less than retracting liquid remaining _{L y} of FDG remaining in storage vial 22 is determined. Incidentally, since it is necessary to seek refuge liquid remaining L _y of FDG remaining in the storage vial 22 Thus, storage vial housing portion 24, such as that provided for the stock solution vial 12, the weight measuring instrument And a liquid amount detection device such as an imaging device.

Then, the determination result in step S206 is when YES, the process proceeds to step S208, FDG return liquid amount _{L r} is returned to the stock solution vial 12. On the other hand, if the decision result in the step S206 is NO, the process proceeds to a step S210 to warn that the liquid amount is insufficient. Then, in step S212, it is confirmed whether or not to return the entire amount of FDG stored in the storage vial 22. The check result of step S212 is when YES, the process proceeds to step S208, FDG shunting fluid remaining _{L y} is returned to the stock solution vial 12. On the other hand, when the confirmation result in step S212 is NO, the FDG return operation is not performed.

  And the dispensing operation | work to the dispensing syringe 25 can be continued using FDG returned to the stock solution vial 12 in this way.

  Next, the operation and effect of this embodiment will be described.

  Also in this embodiment, a part of the FDG is extracted from the stock solution vial 12 and stored in the storage vial 22, and the FDG remaining in the stock solution vial 12 is diluted. Therefore, even if the FDG before dilution has a high concentration, By diluting, the amount of liquid required to obtain the same amount of radioactivity can be increased. Therefore, even if there is a possibility that high-precision dispensing with the syringe 26 may be difficult with a very small amount before dilution, the amount of liquid necessary to obtain the same amount of radioactivity increases, thereby improving the dispensing accuracy. It becomes possible to plan.

In particular, in this embodiment, by previously seeking the density R _c of FDG that is stored in the stock solution vial 12, the relationship between the evacuation liquid amount L _t Keep is retracted in the storage vial 22, each time , minimum extraction radioactivity R it is not necessary to input and various calculations _m, it is possible to perform more efficient dispensing.

In addition, the liquid amount L ₂ before dilution of FDG remaining in the stock solution vial 12 is the minimum extraction radioactivity amount R _m , the allowable minimum discharge liquid amount L _m , the FDG concentration R _c , and the FDG solution stored in the stock solution vial 12. Since the permissible liquid volume L ₀ determined based on the volume L ₁ is set to be equal to or less than ₀ , a liquid volume of FDG that can be dispensed with high accuracy by the syringe 26 after dilution can be left in the stock vial 12.

  In addition, when the amount of FDG in the stock solution vial 12 (the amount of radioactivity) falls below a predetermined value, it is necessary for dispensing by returning at least part of the FDG stored in the storage vial 22 to the stock solution vial 12 FDG is replenished, and the dispensing operation can be continued.

  The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, the dispensing destination is not limited to the syringe 25 and may be a vial.

  In addition, as long as the radioactive liquid can be sucked and discharged, a suction / discharge device other than the syringe 26 may be used. However, the present invention is particularly effective in the case of a disposable syringe that has play in the piston and is difficult to dispense a very small amount of radioactive liquid.

It is a figure which shows the structure of the dispensing apparatus of a radioactive liquid. It is a flowchart which shows the dispensing method of a radioactive liquid. It is a flowchart which shows the flow of detection of the radioactive amount in a stock solution vial, and a liquid amount. It is a figure which shows the state in which a part of radioactive liquid was stored by the storage vial. It is a figure which shows the state which diluted the radioactive liquid in a stock solution vial. It is a figure which shows the state by which the radioactive liquid diluted to the dispensing syringe was dispensed. It is a figure which shows the state in which the radioactive liquid in a stock solution vial is insufficient. It is a figure which shows the state which returned a part of radioactive liquid from the storage vial to the stock solution vial. It is a flowchart which shows the dispensing method of a radioactive liquid. It is a flowchart for demonstrating the return operation | work of a radioactive liquid.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Dispensing apparatus, 12 ... Stock solution vial, 14 ... Radiation detector, 16 ... Control device, 18 ... Weight measuring device, 20 ... Imaging device, 22 ... Storage vial, 25 ... Dispensing syringe, 26 ... Syringe, 28 ... Diluent supply part, 32 ... syringe drive device, 34 ... flow rate switching device.

Claims (5)

A method of dispensing radioactive liquid from an original container to a dispensing container by means of a suction and discharge device,
Extracting a part of the radioactive liquid from the original container and storing it in a storage container,
A method of dispensing a radioactive liquid, comprising diluting the radioactive liquid remaining in the original container and then dispensing the diluted radioactive liquid into the dispensing container.   The at least part of the radioactive liquid stored in the storage container is returned to the original container when the radioactivity amount of the radioactive liquid in the original container becomes a predetermined value or less. A method for dispensing a radioactive liquid as described in 1. The minimum amount of radioactivity extracted from the original container is R _m , the concentration of the radioactive liquid stored in the original container is R _c , the allowable minimum discharge liquid amount of the suction / discharge device is L _m, and R _m When the ratio to R _c (R _m / R _c ) is Z,
3. The method for dispensing a radioactive liquid according to claim 1, wherein when Z <L _m , a part of the radioactive liquid is extracted from the original container and stored in the storage container. The liquid volume L ₂ before dilution of the radioactive liquid remaining in the original container is stored in the minimum extraction radioactivity quantity R _m , the allowable minimum discharge liquid quantity L _m , the concentration R _{c of} the radioactive liquid, and the original container. the dispensing method of radioactive liquid according to claim 3, wherein the determined based on the liquid amount L ₁ of the radioactive liquid and the allowable liquid volume L ₀ or less, and wherein the a. An original container for containing the radioactive liquid;
A dispensing container for dispensing the radioactive liquid from the original container;
A storage container for storing a part of the radioactive liquid extracted from the original container;
A suction / discharge device for sucking and discharging the radioactive liquid;
A diluent supply unit for supplying a diluent for diluting the radioactive liquid;
A flow path switching means for switching the flow path between the original container, the dispensing container, the storage container, the suction / discharge device, and the diluent supply unit;
A part of the radioactive liquid is extracted from the original container, stored in a storage container, the radioactive liquid remaining in the original container is diluted, and then the diluted radioactive liquid is dispensed into the dispensing container. A control device for controlling the suction / discharge device and the flow path switching means,
A dispensing device for a radioactive liquid, comprising:

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