DE2906439A1 - METHOD FOR SEPARATING TECHNETIUM-99M FROM MOLYBAEN-99 - Google Patents

Abstract

1. A process for separating technetium-99m from molybdenum-99 bound to alumina, using eluents from nuclide generators, which comprises fixing on the alumina a copper salt in a weight ratio of Cu to Al2 O3 between 1 : 10 to 1 : 5000, preferably 1 : 50 to 1 : 300, by dissolving the copper salt in water and suspending the corresponding quantity of acid alumina in the resulting solution, subsequently adjusting the pH to a value between 4 and 9, preferably between 6.5 and 7.5, separating the alumina loaded with copper and drying it at temperatures between 120 and 250 degrees C.

Description

HOECHST AKTIENGESELLSCHAFT HOE % 9 / T 036 Dr.KM/Lo

Process for the separation of technetium-99m from molybdenum-99

Technetium-99m has become widely accepted in nuclear medicine diagnostics in recent years because of its favorable physical properties (no corpuscular radiation , / "" - energy of 140 keV, half-life of 6 h) and the associated low radiation exposure for patients and staff. Because of the short half-life of technetium-99m and the associated strong loss of activity during transport, it is rarely sent in isolated form * With a technetium generator, Tc-99m can easily be separated from its mother nuclide Mo-99. Because of the longer half-life of Mo-99 (HWZ = 66.7 h), the loss of activity caused by the transport is kept within limits. Because after

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Separation of the Tc-99m by blood from the molybdenum-99 still present on the column is reproduced again technetium-99m, a technetium-99m generator can be eiuated once or twice a day for one to two weeks,., .. '■ '. ■' ■ _ ■■■ It is known that the calculated quantities of technetium-99m, especially in generators with a larger Mo-99 load, are often significantly below. These yield losses, in special cases yield collapses, are caused by "radiation reduction". The electrons emitted as ß-radiation of Mo-99 reduce the _{technetium (oxidation state +.7) "present in the aluminum oxide column as pertechnetate ion TcO 4} " to a lower oxidation state. In contrast to pertechnetate, the reduced technetium is attached to aluminum oxide The higher the radiation dose in the part of the column in which the Tc-99m arises, the more pertechnetate is reduced. In the case of generators made with Mo-99 obtained from the fission products of uranium-235 (so-called fissured molybdenum), this part of the column is particularly small because of the high specific activity of Mo-99 and consequently the absorbed dose is particularly high.

To prevent yield losses through radiation reduction, Several possibilities have been described, however

all have certain disadvantages.
30th

_{1. An oxidizing agent such as H ^ O 3} or NaOCl can be added to a physiological saline solution serving as an eluant, which oxidizes the reduced technetium again to pertechnetate. The disadvantage of this process is that such oxidizing agents are destroyed again before the eluates are used for marking certain organ-specific substances

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must be _t e.g. by overcooking.

2. After each elution, the Column of fresh oxygen into the system, so will the Radiation reduction prevented as long as there is still enough oxygen in the column. The disadvantage this method is a more cumbersome elution technique.

3. From DE-AS 22 38 503 it is known that by adding | 0 of nitrate or nitrite to the eluent is the reduction

of the pertechnetate ion can be prevented. Against the Use of nitrate and nitrite, both in the eluate and thus get into the organism, she still speaks unexplained role, the nitrite that comes in small amounts also arises from the nitrate, in which cancer formation plays.

The invention is a method for separating Technetium-99m of molybdenum-99 bound to alumina with eluting agents from nuclide generators, characterized in that that a copper (II) salt is added to the elution system.

Salt solutions, in particular, are expedient as eluents physiological saline solutions such as physiological saline solution, furthermore diluted mineral acids such as dilute hydrochloric acid or nitric acid, was used

The copper (II) salt used is, in particular, nitrate , acetate and preferably chloride. · ■ ·

To perform the process is either in the eluant · a copper (II) salt, such as CuGl - 2H, 0 to 10 ~ ² to 10 molar - preferably dissolved in 2 · Ί0 ~ ⁴ to 2 · 10 molar concentration, or Copper (II) salt is fixed on the aluminum oxide in a weight ratio of Cu (IIJ salt to Al ₂ O ₃ between 1:10 and 1: 5000 - preferably between 1:50 and Ϊ: 300)

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To fix the copper (ϊϊ) salt on the aluminum oxide, the appropriate amount of copper (II) -SaXs is dissolved in water and the aluminum oxide (acidic) is suspended in this solution. The pH is then slowly adjusted to a value between 4 and 9, preferably between 6.5 and 7.5, and the aluminum oxide loaded with copper (II) salt is filtered off and stored at temperatures between 120 and 250 ^° C. preferably at 180-220 ⁰ C, dried.

In order to keep the content of copper ions in the sluat low., in this case the generator column is advantageously produced provided that only 1/20 to 1/2, preferably 1/10 to 1/3, the volume of alumina at the top of the column where later the Mo-99 is fixed with the one with copper (Xl) salt loaded alumina is filled, while the remaining part of the column is used for the alumina Available space with untreated rMuminiuno ^ d (sour) is filled /

In both procedures, the content of copper ions in the eluate is usually below 1 ppm, with it in the specified limits does not matter how much copper (XI) salt is added to the eluent or the aluminum oxide. (The normal level of copper in human serum is around 1.2 ppm.)

The method according to the invention enables oils to be produced and the operation of technetium generators without loss of yield due to radiation reduction; it is neither required / sucking dry the generator column between the individual elutions, nor can a mentionable one Part of the yield stabilizer used get into the eluate.

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Example 1:

There are several generator columns, each 1.4 g of aluminum oxide S, acidic, superactive; Riedel de Haen, order no. 31183, loaded with a fission molybdenum solution and eluted every working day, using physiological saline solution as the eluent, to which different amounts of CuCl ₂ * 2H ₂ O have been added. Table 1 shows the elution yields in% based on the Mo-99 activity present.

Tabel

ttolybdenum
activity
at the time
point X CuCl content,
2H ₂ Q in the EIu-
media 1 .EIu-
tion
t = x
-3 days 2.EIu-
tion
t = x 3.EIu-
tion
t = x
+ 1 day 4.EIu-
tion
t = x
+ 2 days 5.EIu-
tion
t = x
+ 3 days 6.EIu-
tion
t = x
+ 4 days 395 ItCi - 77.4 90.1 71.9 57.8 53.3 46.7 632 ItCi 0.01% 80.8 88.0 80.3 79.8 80.4 80.3 384 nCi 0.05% 81.9 90.2 81.3 80.8 81.5 80.7 387 nCi 0.005% 81.2 89.5 80.1 80.2 80.6 80.1

Table 1 shows that when CuCl ₂ —SH ₂ O is added to the elution agent, the elution yield is about 80% in the expected range, while without this addition it falls well below this value from the 3rd elution onwards.

Example 2:

10 g CuCl ₂ * 2H ₂ O are redistilled in 400 ml. Dissolved in water. Then 200 g of Al ₂ O ₃ (acidic) are slowly added with vigorous stirring. Then 10 ml of 20% sodium hydroxide solution are added and the mixture is stirred (15-20 min.) Until the pH has stabilized (it is then around 8.5). Then the pH is adjusted to conc. Hydrochloric acid (approx. 0.5 ml) brought to about pH 7. When the pH value has stabilized, it is decanted with redist. water

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Slurried, decanted again and dried at 200 * 0 for 15 hours.

1 g of untreated aluminum oxide is placed in a glass column (acidic) and above 150 mg of one as described above with Filled with copper ions loaded aluminum oxide. These Column is loaded with Mo-39 and eluted every working day. A physiological saline solution served as the eluent, which was heated together in the autoclave with PVC film, which is usually used for packaging. It is known, that some of the plasticizer of the film in the Elution agent arrives, and that such organic impurities cause severe reductions in yield, For comparison, a column was examined that only had untreated Contained aluminum oxide.

The elution yields are given in Table 2:

Table.-2

Mblybdän-
activity
for calc
opening time
Point Msnge on
CuCl, · 2
H ₂ O / |
Al ₂ O ₃ Elution yields 1. 2. 3. 4th in % (related < 7th on Mon-99) 9. to. ; 570 ItCi
505 ItCi 50 mg 85.0
84.1 5.4
76.6 4.8
80.1 7.0
81.3 5.:. 6th 10.1
74.4 8th. 10.3
73.9 10.0
80.3 11.2
91.2 28.0
91.3 17.1
74.1

Table 2 shows that the addition of CuCl ₂ * 2H ₂ O to aluminum oxide prevents yield collapses which, without this addition, can occur very massively under certain circumstances. ■

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Example 3:

According to the procedure given in Example 2, columns with 10, 20, 30, 40 and 50 mg CuCl ₂ -2H ₃ O per g Al ₂ O ₃ were produced and eluted every working day. The elution yields are given in Table 3:

Table 3

Mblybdän- t
Amount of Elution yields 1. 2. 3. 4, in % (based on Mo-99) 7th 8th. 9. 10. activity
for calc
opening time
Point CuCl ₉ -2HJD / g
^M 2 ° 3 97.2 84.0 75.8 36.7 5. 6th 30.4 22.1 20.4 20.5 597 mCi - 97.6 86.0 86.7 86.8 39.6 57.5 87.5 84.7 84.7 83.6 597 irCi 10 mg 99.0 87.6 89.1 87.6 85.6 95.8 87.1 88.2 85.9 85.1 586 mCi 20 mg 99.0 86.0 87.9 86.9 85.9 95.4 87.3 88.1 86.9 85.6 597 iiCi 30 mg 98.5 87.4 88.6 87.9 86.4 93.8 88.0 87.3 84.6 85.9 592 irCi 40 mg 98.5 88.4 87.3 84.3 88.2 95.4 88.2 88.3 85.3 85.9 592 ItCi 50 mg 87.2 96.9

Table 3 shows that by adding copper chloride to aluminum oxide, the elution yields over the entire period of use are in the expected order of magnitude, while without this addition they are clearly from the 3rd elution are lower.

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Claims (6)

-. 1 - HOE 79 / F 036 patent claims: 1. Process for the separation of technetium-99m from an aluminum oxide bound molybdenum-99 with solvent Nuclide generators, characterized in that the elution system a copper (II) -SaIζ is added. 2. The method according to claim 1, characterized in that - 2 one the eluent a copper (II) salt in 10 to -6-4-5 10 molar, - preferably in 2 * 10 to 2 * 10 molar, - concentration added.
■ 3. The method according to claim 1, characterized in that a copper (II) salt in the weight ratio Cu (II) to Al-O, between 1:10 and 1: 5000 - preferably between 1 ; 50 and 1: 300 fixed on the alumina. 4. The method according to claim 3, characterized in that the copper (H) salt is dissolved in water and the corresponding Amount of acidic alumina suspended in this solution, then adjust the pH to a value between 4 and 9 - preferably between 6.5 and 7.5 - is set and the aluminum oxide so loaded with copper (II) is separated off and dried. 5. The method according to the claims. 1 and 3, thus identified draws that the alumina filling of the generator column consists of two parts, of which the upper part is made of aluminum oxide loaded with copper (H) salt and the lower part Part consists of untreated aluminum oxide. 6. Process according to claims 1 to 4, characterized in that the copper (H) salt is copper (II) chloride. 03Ö036 / 0073