JP2013134061A - High-concentration 99mtc recovery method and high-concentration 99mtc recovery device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To recoverTc at a high recovery rate and to condensate and recover a radioactive nucleus ofTc in which the quantity ofTc solution in the case whereTc is recovered is reduced as much as possible.SOLUTION: As an activated carbon, a spherical activated carbon is used which is composed of a composite body and has a uniform shape, of which the average particle size is desirably 0.2 to 0.4 mm or less and which is filled in a filling density greater than that of an activated carbon from coconut shell of 0.37 to 0.46 g/ml. The spherical activated carbon is used to performTc elution conditioning treatment in whichTc is selectively adsorbed, aMo solution being residual in a spherical activated carbon layer is eluted by dipping water, and a high-concentration alkali liquid is absorbed in the spherical activated carbon adsorbingTc, thereby forming a high-concentration liquid alkalinity. The adsorbedTc for which an alkaline concentration gradient is formed by a low-concentration alkaline liquid and water or by water with respect to the high-concentration liquid alkalinity is recovered as aTc elution liquid. The recoveredTc solution is purified and conditioned, and the purified and conditionedTc is recovered.

Description

The present invention relates to a ^99m Tc high concentration recovery method and a ^99m Tc high concentration recovery apparatus.

⁹⁹ Mo produced by neutron irradiation by neutron irradiation method is dissolved to form a high-concentration Mo solution containing the radionuclide ⁹⁹ Mo as a radiopharmaceutical raw material, and ^99m Tc which is a ⁹⁹ Mo daughter nuclide is generated. Recovery is performed. This method is known as a method for recovering ^99m Tc using (n, γ) ⁹⁹ Mo as a raw material.

Patent Document 1, a ^{99m Tc} as a radiopharmaceutical and its labeled compound precursor, to form a high concentration Mo solution containing radionuclide ^{99 Mo} its parent nuclide, ^99m by utilizing the property that becomes radioactive equilibrium state Tc to generate a generate a high concentration ^{Mo (99} Mo) solution containing radionuclide ⁹⁹ Mo and ^99m Tc, the high concentration ^{Mo (99} Mo) solution was passed through the adsorption column having a built-in active carbon the to the activated carbon It is described that ^99m Tc in a solution is selectively adsorbed, and ^99m Tc is desorbed and purified from activated carbon that has adsorbed ^99m Tc by a desorbing agent to recover high-purity ^99m Tc.

JP 2011-2370 A

As described in Patent Document 1, the applicants of the present patent and the like have been diligently researching a ^99m Tc recovery method using a neutron irradiation method by adsorbing ^99m Tc to activated carbon and recovering the concentrated ^99m Tc. .

The half-life of the radionuclide ^99m Tc of the radiopharmaceutical is 6 hours, and the time from the time when ^99m Tc is adsorbed to the activated carbon to the time when ^99m Tc is recovered is minimized, and preferably within 1 and a half hours to it, as well as ^{99m Tc} was recovered at a high recovery rate, it is important that as much as possible reduce the amount of ^{99m Tc} solution when recovered ^{99m Tc} provides a radiopharmaceutical.

The present invention, while using the activated carbon when adsorbing the ^99m Tc in view of such points, and minimize the time in the step from the time of adsorbing the ^99m Tc to the activated carbon until the time to recover ^99m Tc, and ^99m Tc It was collected with a high recovery rate, and minimize the amount of ^{99m Tc} solution when recovered ^{99m Tc,} an object of recovering the radionuclide concentration is ^{99m Tc.}

According to the present invention, the activated carbon is composed of a synthetic material, has a uniform shape, has an average particle size smaller than that of coconut shell activated carbon, and adsorbs ^99m Tc using spherical activated carbon having a large specific surface area. Features.

Specifically, the present invention is a high-concentration Mo solution produced by irradiating neutrons by a neutron irradiation method and formed by dissolving the radionuclide ⁹⁹ Mo of the parent nuclide, and the generated daughter nuclide. ^A high-concentration Mo solution containing ^99m Tc is stored in a Mo tank,
The high-concentration Mo solution is passed through an activated carbon column containing activated carbon as an activated carbon layer to selectively adsorb ^99m Tc in the high-concentration Mo solution to the activated carbon.
The Mo staying in the activated carbon layer is removed by leaching, the high concentration recovery method of ^99m Tc to the ^99m Tc adsorbed by the activated carbon to recover the ^99m Tc ^99m Tc enriched performs desorption processing of activated carbon,
As the activated carbon, a spherical activated carbon made of a synthetic material, having a uniform shape and an average particle size of 0.60 mm or less and filled with a packing density of coconut shell activated carbon larger than 0.37 to 0.46 g / ml, ^99m Tc is selectively adsorbed,
⁹⁹ Mo retained in the spherical activated carbon layer is leached by passing a cleaning solution,
^The spherical activated carbon that adsorbs ^99m Tc is occluded with a high-concentration alkaline solution, and is subjected to a ^99m Tc elution conditioning treatment exhibiting a high-concentration alkaline liquid property. The adsorbed ^99m Tc is desorbed and recovered as a ^99m Tc eluate,
A ^99m Tc high concentration recovery method is provided, wherein the recovered ^99m Tc solution is purified and adjusted, and the purified and adjusted ^99m Tc solution is recovered.

The present invention also provides a high concentration recovery method of ^99m Tc, characterized in that neutralization is adjusted by passing through the alumina column without adding an acidic solution to the recovered ^99m Tc solution. provide.

The present invention also provides a high concentration recovery method of ^99m Tc, wherein the purification adjustment described above is performed at room temperature.

The present invention is also characterized in that, in one described above, the ^{99 Mo} solution staying in the spherical activated carbon layer was leached by passing liquid water only, to provide a high concentration recovery method of ^{99m Tc,} which comprises carrying out at room temperature.

In the present invention, the high-concentration Mo solution feeding to the Mo tank and the high-concentration Mo solution feeding from the Mo tank to the activated carbon column are performed under a reduced pressure flow through the decompression line of the liquid feeding system unit. A method for recovering a high concentration of ^99m Tc is provided.

The present invention is also a high-concentration Mo solution formed by dissolving the parent nuclide radionuclide ⁹⁹ Mo produced by neutron irradiation by the neutron irradiation method, and the daughter nuclide produced is ^99m Tc. High concentration Mo solution storage means for storing a high concentration Mo solution containing
The high-concentration Mo solution is passed through an activated carbon column containing activated carbon as an activated carbon layer, ^99m Tc in the high-concentration Mo solution is selectively adsorbed on the activated carbon, and ^99m Tc adsorption is performed to ^{retain the 99} Mo solution. A ^99m Tc highly concentrated recovery device that adsorbs ^99m Tc to activated carbon and concentrates and recovers it.
^99m Tc is selected as the activated carbon, which is composed of a synthetic material, and has a uniform shape and an average particle size of 0.60 mm or less, and is filled at a packing density greater than 0.37 to 0.46 g / ml of coconut shell activated carbon. An active column containing spherical activated carbon that adsorbs automatically,
Mo leaching means for washing and leaching ⁹⁹ Mo retained in the spherical activated carbon layer by passing water.
Spherical activated carbon with a high concentration alkaline solution is occluded, ^{99m Tc} elution conditioning processing means for ^{99m Tc} elution conditioning process to form a high-concentration alkaline solution resistance,
^99m Tc eluate recovery means for recovering adsorbed ^99m Tc as ^99m Tc eluate, in which an alkali concentration scent is formed by water with respect to the high concentration alkali liquidity;
^99m Tc eluate purification adjustment means for adjusting the recovered ^99m Tc solution purification, and ^99m Tc recovery means for recovering ^99m Tc from the purified ^99m Tc eluate,
The high concentration collection ^| recovery apparatus of ^99mTc characterized by having this.
The present invention is also characterized in that the ^99m Tc eluate purification adjustment described above is passed through the alumina column without adding an acidic solution, whereby the alumina column has a ^99m Tc eluate purification adjustment action. ^99m Tc high concentration recovery device is provided.

According to the present invention, in any of the above, the Mo leaching means is leached by passing a ⁹⁹ Mo solution staying in the spherical activated carbon layer, and ^99m Tc recovery means is used for the ⁹⁹ Mo solution staying in the spherical activated carbon layer. Provided is a ^99m Tc high concentration recovery device characterized by passing water through leaching.

The present invention is also, ^99m Tc which comprise Mo tank for storing a high concentration Mo solution containing ^99m Tc as described above, to form a high-level lead shielding Mo tank unit, to recover the ^99m Tc provided with the activated charcoal column A waste liquid tank for storing the waste liquid generated at the time of recovery is provided, a medium level lead shielded Tc recovery unit is formed, and these units can be separated and the Mo tank and the activated carbon column are connected by piping. A ^99m Tc high concentration recovery device is provided.

The present invention uses a spherical activated carbon made of a synthetic material and having a uniform shape and an average particle size of 0.40 mm or less as the activated carbon, thereby ensuring a large specific surface area and ^{99 m} from the time when ^{99 m} Tc is adsorbed on the spherical activated carbon. The radionuclide which is ^99m Tc, which can reduce the time in the process until the time of recovering Tc, and recovers ^99m Tc at a high recovery rate and reduces the amount of ^99m Tc solution when ^99m Tc is recovered. Can be concentrated and recovered.

The block diagram which shows embodiment of the Example of this invention. The figure which shows the flow of a present Example. The figure which shows the comparison of the used activated carbon. The figure which shows the activated carbon method Example.

  Embodiments of the present invention will be described below with reference to the drawings.

  Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of a high concentration recovery apparatus of ^99m Tc which is an example of the present invention.
In FIG. 1, a ^99m Tc high concentration recovery apparatus 100 is composed of a Mo tank unit 1, a Tc recovery unit 2, a liquid feeding system unit 3, and a reagent supply unit 4.

  The Mo tank unit 1, the Tc recovery unit 2, and the liquid feeding system unit 3 are arranged in a manufacturing chamber inside the hot cell 5, and the reagent supply unit 4 and a control unit (not shown) are arranged in an operation chamber outside the hot cell. The

The Mo tank unit 1 includes a Mo tank 11, a Mo tank 12, and a Mo waste liquid tank 13. The Mo tank 11 and the Mo tank 12 are preliminarily irradiated with neutrons in a nuclear reactor to produce ⁹⁹ Mo, and supplied with a No ₂ ⁹⁹ MoO ₄ solution generated by dissolving the contained MoO ₃ with an alkaline solution (NaOH). The That is, a Mo solution containing radionuclide ⁹⁹ Mo as a radiopharmaceutical raw material is supplied to and stored in either the Mo tank 11 or the Mo tank 12. ^{When 99} MoO ₃ is dissolved in an alkaline solution, a pH neutral Na ₂ ⁹⁹ MoO ₄ solution is formed.

The Mo solution containing radioactive ⁹⁹ Mo is, for example, a high concentration Mo solution containing 500 g of Mo in 2 L.

Pipings 16 and 17 provided with a valve 14 and a valve 15 are provided at the bottom of the Mo tank 11 and the Mo tank 12, and are connected to a pipe 18 from the Mo waste liquid tank 13 via a valve 19. The pipe 18 is connected to an activated carbon column 32 constituting the ^99m Tc generator 31. The waste liquid tank 13 is connected to a valve 19 through a pipe 17 '.

  The Mo tank 11 and the Mo tank 12 include a pressure detector 23 and have a function as a liquid level adjustment mechanism.

An Mo solution supply line 41 from an external dissolved Mo supply source is connected to the Mo tank 11 and the Mo tank 12, and a Mo solution recirculation pipe 20 is connected to the Mo tank 11, the Mo tank 12, and the Mo waste liquid tank 13. Is done. The recirculation pipe 20 is connected to a waste liquid discharge pipe 41 and is also used for discharge from the Mo waste liquid tank 13. The waste liquid tank 13 is connected to the liquid feeding line unit 3 via the pipe 21 to depressurize the waste liquid tank 13 and the residual Mo solution from the Mo tank 11 and the Mo tank 12 is introduced. The hydraulic pressure lines 21 connected to the upper portions of the Mo tank 11, the Mo tank 12, and the Mo waste liquid tank 13 are connected to the decompression line of the liquid feeding system unit 3. The supply line 20 and the hydraulic pressure line 21 are provided with connection valves as illustrated. The supply of the alkaline solution or H ₂ O from the supply line of the reagent supply unit 4 is supplied to the Mo tank 11, the Mo tank 12, the activated carbon column 32 through the pipe 22 and the pipe 48, and the adjustment tank 33 through the pipe 44. Can be done through.

  The Mo tank unit 1 is shielded from lead, and serves as a Mo tank unit 24 of a high level lead shielding unit as a whole.

  The Tc recovery unit 2 includes an activated carbon column 32, a conditioning tank 33, an alumina column (1) 34, an alumina column (2) 35, a Tc recovery unit 38, a waste liquid tank (1) 37, a waste liquid tank (2) 36, and a line heater 39. And the column heater 40, which is a medium level lead shielded Tc recovery unit 25.

The ⁹⁹ Mo solution in which the flow rate and flow rate from the Mo tank 11 or Mo tank 12 are controlled is introduced into the activated carbon column 32 via the pipe 18. The activated carbon column 32 is connected to the pipe 20 at the bottom, and the pipe 20 is branched to the pipe 42 via the valve 45. The pipe 18 is provided with a valve 46 and a valve 47.

  The activated carbon column 32 is made of a synthetic material, and is packed with spherical activated carbon having a uniform shape and an average particle diameter of 0.4 mm or less and an average pore diameter smaller than that of coconut shell activated carbon.

The activated carbon column 32 is configured such that heated H ₂ O is supplied from a pipe 48 connected to the valve 47. The pipe 48 is provided with a line heater 40 to heat the H ₂ O or alkali solution sent from the liquid feed line. The solution heated in this way is put into the activated carbon column 32.

And ⁹⁹ Mo collapse of ⁹⁹ Mo solution in Mo ^{tank, 99m} Tc is generated with increasing time. ⁹⁹ Mo and ^99m Tc have the property of reaching an over-equilibrium state in about 24 hours. ^99m Tc produced by ⁹⁹ Mo decay coexists in the Mo tank.
The ⁹⁹ Mo solution in the radiation equilibrium state is passed through the activated carbon column 32. ^99m Tc is adsorbed on the spherical activated carbon. Spherical activated carbon has the property of adsorbing ^99m Tc but not ⁹⁹ Mo. For this reason, the introduced ⁹⁹ Mo solution passes through the activated carbon column 32 and is quickly returned to the Mo tank 11 or the Mo tank 12.

However, a very small amount of ⁹⁹ Mo solution remains in the spherical activated carbon layer. H ₂ O (pure water) is passed through the pipe 48 to remove impurities other than the ⁹⁹ Mo solution and ^99m Tc remaining in the activated carbon layer. The washing water from the activated carbon column 32 is led out to the waste liquid tank (1) 37 through the pipe 20, the valve 49, and the pipe 50 and stored.

Subsequently, the high-concentration alkaline liquid sent through the liquid feed line following the above-mentioned H ₂ O supply is introduced into the activated carbon column 32 from the pipe 48 and the pipe 18, passed through the spherical activated carbon, occluded, and concentrated. Condition before ^99m Tc elution with alkaline solution.

  The column heater 39A can heat the activated carbon column 32.

The activated carbon column 32 after the conditioning described above is heated.
Next, H ₂ O is passed through the spherical activated carbon through the activated carbon column 32 in a heated state. Thus, ^99m Tc is easily eluted from the spherical activated carbon by creating a concentration odor with respect to the high alkali in the previous step and heating.

  The waste liquid from the activated carbon column 32 is led out to the waste liquid tank (1) 37 via the pipe 20, the valve 49, and the pipe 50 and stored.

The eluted ^99m Tc is led out to the adjustment tank 33 by the action of the hydraulic pressure line through the pipe 42 and is retained. Here, the liquidity (NaCl concentration) of the solution is adjusted. For this adjustment, 6% NaCl introduced through the liquid feed line and the pipe 44 is used.

^In this example, 6% NaCl is used for ^99m Tc liquidity adjustment, and the recovered liquid is adjusted to 0.9% NaCl. Conventionally, it has been necessary to adjust the pH using HCl in the adjustment tank 33, but by ^{reducing the} amount of alkali for elution of ^99m Tc using spherical activated carbon, it is possible to pass acidic alumina through purification in the next step. By adjusting the pH, the pH can be adjusted sufficiently. Therefore, it is not necessary to adjust the pH with the adjustment tank 33.

The ^99m Tc solution with the adjusted liquidity (NaCl concentration) is led to the alumina column (1) 34 through the pipes 42 and 46 by the action of the hydraulic pressure line. The alumina column exhibits the performance of an acidic alumina column. ^{By passing the 99m} Tc solution through the alumina column (1) 34, the ^99m Tc solution is purified. This purification is further performed with an alumina column (2) 35. Again, the alumina columns are washed with a small amount of physiological saline.

The purified ^99m Tc solution is recovered in the Tc recovery container 38 via the piping 46 and the piping 47. The physiological saline used for washing is collected in the Tc collection container 38 through the pipe 47. The pipe 42 is connected to the decompression line via the pipe 43. The waste liquid tank (1) 37 and the waste liquid tank (2) 36 can be taken out to the outside.

  The liquid feeding system unit 3 includes a large cylinder 61, the above-described decompression line 62, and pipes 63 and 63A connecting these.

The reagent supply unit 4 controls the reagent 1.3M-NaOH, 0.9% -NaCl, 6% -NaCl and H ₂ O supply device 64 and various valves 65 to control these supply control means 66 and the supply line described above. 67 and a pipe 68 connecting them.

  According to this example, the Mo tank unit 1 is configured as a high level lead shielding unit 24, the Tc recovery unit 2 is configured as a medium level lead shielding unit 25, and the Mo tank unit 1 or the Tc recovery unit 2 is configured. Since various devices and devices are arranged in each unit, the operation unit is divided for each radioactivity level, so that the degree of freedom in layout can be increased.

And according to the present Example, it is produced by the (n, γ) method which is a neutron method, and has a low specific activity (1 / 10,000 of the fission method) ⁹⁹ Mo to ^99m Tc as a radiopharmaceutical and a labeled compound raw material When used, a very small amount of ^99m Tc in high-concentration Mo ( ⁹⁹ Mo) can be purified with high yield without rapid mixing of ⁹⁹ Mo, and the operability for recovering radionuclide ^99m Tc with a short half-life can be ^achieved. An excellent apparatus and method are provided.

According to this example, the high concentration Mo solution formed by irradiating neutrons by the neutron irradiation method and formed by dissolving the parent nuclide radionuclide ⁹⁹ Mo contains the daughter nuclide ^99m Tc. Mo tank part 1 as a high concentration Mo solution storage means for storing Mo solution is formed.

Further, the activated carbon is made of a synthetic material, and has a uniform shape and an average particle size of 0.60 mm or less, preferably 0.4 mm or less, and a packing density larger than 0.37 to 0.46 g / ml of coconut shell activated carbon. It is provided with an activated carbon column 32 that selectively adsorbs ^99m Tc from ⁹⁹ Mo using spherical activated carbon that can be packed with

This activated charcoal column 32 the spherical activated carbon layer, by storing a high concentration alkali solution spherical activated carbon to adsorb ^{99m Tc, 99m Tc} elution condition processing for ^{99m Tc} elution condition processing to form a high-concentration alkali solution of means, by the water to form the alkali concentration odor distribution for the high-concentration alkaline solution resistance include ^99m Tc eluate collecting means for collecting the adsorbed ^99m Tc as ^99m Tc eluent.

According to the above, the adjustment tank 33 as ^99m Tc eluate adjusting means for adjusting the liquidity / liquid amount of the recovered ^99m Tc solution, the alumina column (1) 34 through which the adjusted ^99m Tc eluate is passed, the alumina column (2) The final ^99m Tc eluate is neutralized and purified with these alumina columns to which 35 is connected, and is made equivalent to physiological saline.

The purified ^99m Tc eluate is taken out and collected, adjusted as a radiopharmaceutical, and supplied to a medical institution.

FIG. 2 shows a process for recovering ^99m Tc.
^99m Tc high concentration recovery is the first step with ⁹⁹ Mo solution uptake (S1). ^{The 99} Mo solution is formed by dissolving the radionuclide ⁹⁹ Mo of the parent nuclide, which is produced by irradiating neutrons by the neutron irradiation method.

⁹⁹ Mo has a property of forming a radiation equilibrium state with ^99m Tc generated by the decay of ⁹⁹ Mo. The ⁹⁹ Mo solution formed by this (n, γ) method is taken into the Mo tank and stored.

^{A 99m} Tc adsorption and collection step is performed (S2). This step is an adsorption collection step using an activated carbon column equipped with spherical activated carbon.

A ⁹⁹ Mo solution is stored in the Mo tank 11, and a maximum of 2 liters can be stored.
In the Mo tank 11, ^99m Tc in a radiation equilibrium state coexists. At this time, the other Mo tank 12 is empty. Thus, one of the tanks is always empty.

The ⁹⁹ Mo solution in the Mo tank 11 passes through the activated carbon column 32 and is transferred and stored in the Mo tank 12. At this time, the ⁹⁹ Mo solution does not stay in the activated carbon but passes through the activated carbon as it is and is transferred to the Mo tank 12.

Only ^99m Tc is adsorbed on the activated carbon and ⁹⁹ Mo passes without adsorbing and is transferred to the other tank.

Since activated carbon is used, a small amount of Mo remains in the holes. The Mo is washed with a small amount of H ₂ O and collected in the previous Mo tank 12.
Most of the ⁹⁹ Mo solution passes through activated carbon and is collected in a separate tank.
The next day (after 24 hours), starting from the Mo tank 12, a ^99m Tc recovery operation is performed.
In the flow, Mo tank 12 → activated carbon column 32 → Mo tank 11

In this way, ^99m Tc recovery operation is performed using alternating Mo tanks up to the allowable range of ⁹⁹ Mo amount.

^{When 99} Mo amount becomes low, it is discarded and stored in the waste liquid tank (for Mo) 13. Then, a new ⁹⁹ Mo solution is supplied to one of the Mo tanks.

Various types of waste liquid tanks 13 can be used.
Store in a Mo tank for a certain period to attenuate the radioactivity and finally discard it.

^{A 99m} Tc elution pretreatment step is performed (S3). This process consists of a ⁹⁹ Mo cleaning process adhering to the spherical activated carbon and an activated carbon conditioning process, which is a ^99m Tc elution conditioning process in which the spherical activated carbon is occluded into the spherical activated carbon to form a highly concentrated alkaline liquid property.

⁹⁹ Mo cleaning operation is performed, and after Mo cleaning / recovery with a small amount of H ₂ O, the remaining Mo cleaning operation is performed.

At room temperature, 100 Mo of H ₂ O is used to wash ⁹⁹ Mo remaining in the column, and the waste liquid tank (1) 38 is discarded.
In this operation, although it was a heating (85 degreeC) condition, it changed to room temperature and the kind and liquid volume of the reagent were improved.

-Activated carbon conditioning operation (alkali occlusion)
In order to facilitate Tc leaching, the activated carbon is conditioned by passing an alkali (1.3 M NaOH) through the activated carbon adsorbed on Tc.

The passing liquid is discarded in the waste liquid tank (1) 38.
In this operation, the alkaline solution used is the same. The column temperature condition was improved from the warming condition to room temperature.

^{A 99m} Tc elution step is performed (S4). This step is performed at a heating operation of 80 ° C. Water is used as the eluent to form an alkali concentration scent for high concentration alkaline liquid spherical activated carbon. (Conventionally, 0.1M NaOH as a low-concentration alkaline solution was passed, and then water was passed, but even if only water was passed without passing the low-concentration alkaline solution, the alkali concentration odor distribution is high, it is possible to elute the ^{99m Tc.)} elution of ^{99m Tc} by passing liquid water alone, humoral adjustment in the next step does not require pH adjustment, allows only the preparation of NaCl concentration Become.

The alkali-conditioned activated carbon column 32 can elute ^99m Tc with only H ₂ O under the best conditions.

By passing H ₂ O at a specified flow rate, the adsorbed ^99m Tc is eluted by an alkali concentration gradient.

The eluate (containing ^99m Tc) is collected in the adjustment tank 33.
A major characteristic of the spherical activated carbon is that ^99m Tc can be eluted at 80 ° C. (low temperature heating) and in a small amount. Reagents could also be eluted with H ₂ O alone, and sufficient recovery was possible without using a low-concentration alkaline solution. The liquid volume was also improved to a small amount.

^{A 99m} Tc liquidity adjustment step is performed (S5). In this step, the liquidity (physiological saline concentration: 0.9% NaCl) of the ^99m Tc eluate showing alkalinity is adjusted. Use high-concentration (6%) NaCl so as not to increase the amount of ^99m Tc recovery liquid as much as possible.

  A small amount of about 6% NaCl solution is added to the eluate collected in the adjustment tank 33 to adjust the salt concentration.

The Tc eluate collected in the adjustment tank 33 is alkaline. However, since the volume of the activated carbon and the amount of the alkaline solution used under the previous conditions were small, the alkali concentration (absolute amount) was much smaller than the eluate using the coconut shell activated carbon before the improvement.
With this liquid amount and alkali amount, 5 g of alumina (acidic) was sufficiently buffered, and a neutral solution was possible.

The alumina used is conditioned with HCl and is acidic.
However, if the alumina used is passed through H ₂ O or a solution with a low salt concentration, aluminum (AL), which is a structure, may be dissolved and mixed into the final Tc-purified recovered liquid. The dissolved AL is collected.

  Therefore, the eluate was increased to a salt concentration equivalent to the same physiological saline (0.9% -NaCl) as the final Tc recovery solution and passed through the alumina column.

  The passing liquid had no dissolution of AL and had a pH of 5 to 6, which was well suited to the pH range of 4.5 to 7 in the Pharmaceutical Affairs Law.

  An operation of adjusting the salt concentration by adding an approximately 6% NaCl solution was added to the operation of increasing the salt concentration at this time.

  Since the amount of liquid and the amount of alkali are large, the pH adjustment operation is performed with an acid solution (1.0 M HCl), and the operation according to this example is improved compared to the operation where pH adjustment and salt concentration adjustment are performed. In addition, the pH sensor, reagent line, reagent supply device, etc. were eliminated and the system was greatly improved.

^{A 99m} Tc purification step is performed (S6). This process is purified by an alumina column. The ^99m Tc recovery liquid showing alkaline properties is neutralized by the acidic properties of the alumina column. Therefore, in this paragraph, it is no longer necessary to provide a neutralization step with HCl.

-Eluate pH adjustment and purification step The eluate adjusted in the adjustment tank 33 passes through the alumina columns 34 and 35 by reducing the pressure of the Tc recovery container 38, and is recovered in the Tc recovery container 38.
By this operation, the pH of the Tc eluate is adjusted and recovered. However, Tc solution remains in alumina.
The purified ^99m Tc solution is recovered as a ^99m Tc high-concentration solution (S7).

-Alumina column cleaning & Tc recovery Since there is much Tc remaining in the alumina columns 34 and 35, recovery is performed.
The adjustment tank 33 is filled with 0.9% NaCl solution. It passes through the alumina columns 34 and 35 again, and the remaining Tc is recovered in the Tc recovery container 38.

  FIG. 3 shows a comparison of the activated carbon used. For comparison, Shirakaba (registered trademark) and Kureha A-BAC (registered trademark) were used as coconut shell activated carbon.

  In the present embodiment, as described above, it is made of a composite, has a uniform shape and an average particle size of 0.6 mm or less, and has a packing density higher than the packing density of coconut shell activated carbon of 0.37 to 0.4 g / l, for example, Spherical activated carbon filled at 0.6 g / ml is used.

The average particle diameter is preferably 0.2 to 0.6 mm, and more preferably 0.2 to 0.4 mm.
● Types of spherical activated carbon Spherical activated carbon is synthesized by the same method by the manufacturer, and is simply divided according to particle size by sieving, and the properties such as pore distribution show similar properties.

Table 1 shows the results of ^99m Tc (Re) adsorption and elution characteristic test, which is Kureha's spherical activated carbon.

From the test results, the difference in adsorption and elution of ^99m Tc is that SP <MP <LP <G and the particle size is large. When the activated carbon column is packed, there will be a difference in the packing voids and a difference in the contact efficiency. It is estimated that

Even with the largest diameter G-BAC G70R, ^99m Tc adsorption rate can be secured above a certain level by reducing SV (space velocity: relationship between contact time between activated carbon and passing liquid).

Kureha A-BAC SP has an average particle size of 0.2 to 0.4 mm, a packing density of 0.6 g / ml, and shows the best test results for ^99m Tc adsorption and elution compared to coconut shell activated carbon. . Kureha A-GBAC G70R has an average particle size of 0.6 mm, but the packing density can be higher than this value compared to 0.37 to 0.46 g / ml of coconut shell activated carbon. Shows performance over activated carbon.
● Comparison of spherical activated carbon and coconut shell activated carbon (granular activated carbon)

(1) Impurity content Both spherical activated carbon and coconut shell activated carbon have ^99m Tc adsorption and elution ability.
One merit of using spherical activated carbon in the activated carbon column is that spherical activated carbon is produced industrially and therefore has less impurities.
In the 800 ° C. ashing test, the ash content after the test contains impurities 10 times or more compared to the spherical activated carbon. This is due to the fact that the coconut shell activated carbon is inevitably soil minerals remain for the coconut shell. Since the raw material for BAC is petroleum pitch, it contains less mineral than coconut shell.
For the small amount of impurities, the radionuclide production process as a radiopharmaceutical is advantageous.

(2) Adsorption performance associated with activated carbon structure Generally, adsorption of activated carbon occurs mainly in micropores (small pores), and transport is made in macropores (large pores). This is a so-called size effect.
BAC has the property of having few macropores.
Since BAC has almost no macropore, it is considered that ^99m Tc directly reaches the micropore and promotes adsorption. This property also works favorably during elution.

  Like coconut shell activated carbon, plant-based activated carbon has a complex network of macropores and micropores, as can be seen from the SEM image, etc., creating a puddle-like part and improving the adsorption performance. It is estimated that the cleaning effect at the time of desorption is deteriorated.

Naturally, the spherical activated carbon has a spherical shape, which is advantageous for increasing the packing density. Spherical activated carbon has good liquid permeability and is advantageous for improving contact efficiency. For this reason, a density can be raised and a packing density can be made high. If this is the same volume, the filling amount can be increased and the ^99m Tc saturated adsorption amount per unit weight can be increased as compared with the coconut shell activated carbon, which is advantageous for downsizing the apparatus.

Coconut shell activated carbon is crushed and highly activated to increase the surface area. Therefore, powdered products are apt to be produced, and the shape cannot be made spherical. For this reason, as described above, spherical activated carbon is advantageous for increasing the ^99m Tc saturated adsorption amount per unit weight.

  Since spherical activated carbon is spherical, it has higher strength than coconut shell activated carbon and is advantageous in terms of elution.

  FIG. 4 shows an activated carbon example, showing a comparative example and an example of the present invention. Each step indicates a step in FIG.

  In FIG. 4, Kureha spherical activated carbon BAC is used as the spherical activated carbon. Kureha Spherical Activated Carbon BAC is known as a spherical uniform shaped activated carbon that is spheroidized without using a binder, carbonized, and bandited (pore formation) using petroleum pitch as a raw material. As coconut shell activated carbon, Nippon Envirochemicals' coconut shell high-altitude activated charcoal and coconut shell ordinary bandit activity are known.

  In step S2, the downflow method is preferably used by utilizing spherical activated carbon to take advantage of the above-described properties. That is, safety can be improved by reducing pressure instead of pressurizing to relax various solutions.

  In step S3, the cleaning may be performed at room temperature (no heating device is required), and the apparatus can be simplified.

In the S3 step, it is possible to eliminate the need for a washing operation using NaHCO ₃ warming foaming, and the operation flow can be simplified.

  In step S3, since the particle size and filling volume of the spherical activated carbon were reduced, the liquid volume could be reduced to 1/3 even when the liquid speed was reduced to 1/2, and the operation time could be shortened.

  In step S4, the heating temperature, which was 130 ° C. in the coconut shell activated carbon method, was preferably 80 ° C., and the operating conditions were relaxed.

In step S4, the NaOH used in the previous step can be eluted with ^99m Tc without adding only the amount retained in the activated carbon column. Preferably, ^99m Tc can be eluted by passing H ₂ O, and the operation flow is simplified.

  In step S4, since the volume of spherical activated carbon could be reduced, the amount of the eluate was reduced and the operation flow was reduced.

In step S5, since the alkali concentration of the ^99m Tc solution has been reduced by the above-described process improvement, only the flow to an alumina column (acidic alumina), which is a column containing alumina in the subsequent process, is performed without performing a neutralization operation. Thus, neutralization adjustment, that is, pH adjustment became possible.

In S6 ^step, the ^99m Tc recovering solution to remove impurities such as ⁹⁹ Mo by passing an alumina column, and the pure product.

In FIG. 4, by using spherical activated carbon, the time required for all steps S2-S7 can be reduced to 2 hours, which is half that of the comparative example. Considering that the half-life of ^99m Tc is 6 hours, the half-life of the entire process time is a great merit in supplying the radionuclide as an injection solution. Moreover, the reduction of the recovery amount of the ^99m Tc solution leads to a reduction of the amount as an injection solution, which is a great merit.

DESCRIPTION OF SYMBOLS 1 ... Mo tank part, 2 ... Tc collection | recovery part, 3 ... Liquid feeding system part, 4 ... Reagent supply part, 11, 12, 13 ... Mo tank, 32 ... Activated carbon column, 33 ... Adjustment tank, 34 ... Alumina column (1 ), 35 ... alumina column (2), 38 ... Tc recovery container, 39, 40 ... heater, 100 ... ^99m Tc high concentration recovery device.

Claims (9)

A high-concentration Mo solution produced by dissolving the parent nuclide radionuclide ⁹⁹ Mo produced by neutron irradiation by a neutron irradiation method, and containing a daughter nuclide ^99m Tc in a Mo tank Stored in
The high-concentration Mo solution is passed through an activated carbon column containing activated carbon as an activated carbon layer to selectively adsorb ^99m Tc in the high-concentration Mo solution to the activated carbon.
The Mo remaining in the activated carbon layer is removed by leaching, the high concentration recovery method of ^99m Tc to the ^99m Tc adsorbed by the activated carbon to recover the ^99m Tc ^99m Tc enriched performs desorption processing of activated carbon,
As the activated carbon, a spherical activated carbon made of a synthetic material, having a uniform shape and an average particle size of 0.60 mm or less and filled with a packing density of coconut shell activated carbon larger than 0.37 to 0.46 g / ml, ^99m Tc is selectively adsorbed,
The ⁹⁹ Mo solution remaining in the spherical activated carbon layer is leached by passing a cleaning solution,
^The spherical activated carbon that adsorbs ^99m Tc is occluded with a high-concentration alkaline liquid, and is subjected to a ^99m Tc elution conditioning process that exhibits high-concentration alkaline liquidity. Alternatively, ^99m Tc adsorbed by forming an alkali concentration scent with water is recovered as a ^99m Tc eluate,
Recovered ^99m Tc solution was adjusted purification, high concentration recovery method of ^99m Tc, which comprises recovering the ^99m Tc solution purified adjusted. The method for recovering a high concentration of ^99m Tc according to claim 1, wherein neutralization is adjusted by passing through the alumina column without adding an acidic solution to the recovered ^99m Tc solution. According to claim 1 or 2, ^99m Tc, characterized in that the ^{99 Mo} solution remaining on spherical activated carbon layer was leached by passing liquid water, and passing liquid water leaching ^{99 Mo} solution staying in the spherical activated carbon layer High concentration recovery method. 2. The high concentration Mo solution feeding to the Mo tank and the high concentration Mo solution feeding from the Mo tank to the activated carbon column according to claim 1 are performed by a decompression flow through a decompression line of a liquid feeding system unit. ^99m Tc high concentration recovery method characterized by the above-mentioned. A high-concentration Mo solution formed by dissolving the radionuclide ⁹⁹ Mo, the parent nuclide, produced by neutron irradiation by the neutron irradiation method, and storing the high-concentration Mo solution containing ^99m Tc as the daughter nuclide High concentration Mo solution storage means,
The high concentration Mo solution, activated carbon provided with, ^{99m Tc} suction means for selectively adsorbing ^{99m Tc} of the high concentration Mo solution to the activated carbon passed through the activated charcoal column which incorporates as active carbon layer, the activated carbon ^{In 99m} Tc highly concentrated recovery equipment that absorbs ^99m Tc, concentrates and recovers it,
^99m Tc is selected as the activated carbon, which is composed of a synthetic material, and has a uniform shape and an average particle size of 0.60 mm or less, and is filled at a packing density greater than 0.37 to 0.46 g / ml of coconut shell activated carbon. An active column containing spherical activated carbon that adsorbs automatically,
Mo leaching means for washing and leaching ⁹⁹ Mo solution remaining in the spherical activated carbon layer by passing water through,
Spherical activated carbon with a high concentration alkaline solution is occluded, ^{99m Tc} elution conditioning processing means for ^{99m Tc} elution conditioning process to form a high-concentration alkaline solution resistance,
The high relative density lye resistance, low concentration alkali solution, and water ^{99m Tc} eluate collecting means for collecting the ^{99m Tc} adsorbed by the formation of alkali concentration odor distribution as ^{99m Tc} eluate with water,
^99m Tc eluate purification adjustment means for adjusting the recovered ^99m Tc solution purification, and ^99m Tc recovery means for recovering ^99m Tc from the adjusted ^99m Tc eluate,
^99m Tc high concentration recovery apparatus characterized by having. According to claim 5, wherein the ^{99m Tc} eluate purification adjustment without passing liquid alkaline solution, the alumina column by being passed through the alumina column is characterized by forming the ^{99m Tc} elution modulating effects ^99m High concentration recovery device for Tc. The high concentration recovery apparatus for ^99m Tc according to claim 5, wherein the Mo leaching means in the column and the ^99m Tc elution conditioning treatment are performed at room temperature. The Mo leaching means in any one of claims 5 to 7 is leached by passing ⁹⁹ Mo solution remaining in the spherical activated carbon layer, and ^99m Tc recovery means is used for leaching the ⁹⁹ Mo solution remaining in the spherical activated carbon layer. ^99m Tc high concentration recovery device characterized by passing water. According to claim ^5, provided with a Mo tank for storing a high concentration Mo solution containing ^99m Tc, to form a high-level lead shielding Mo tank unit, to recover the ^99m Tc includes the activated carbon column ^99m Tc generators and ^99m A waste liquid tank for storing the waste liquid generated at the time of Tc recovery is provided to form a medium level lead shielded Tc recovery unit, and these units can be separated and the Mo tank and the ^99m Tc generator are connected by piping. ^99m Tc high concentration recovery device characterized by the above.

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