1. Radionuclide generators for Nuclear Medicine
Brookhaven National Laboratory
Nuclear Chemistry Summer School
Sarah Weßmann
07/27/2006

2. Overview Theoretical Background Role of radionuclide generator
Definition
Setup
Examples
Role of radionuclide generator
Properties/ requirements
Conclusion

3. Overview Theoretical Background Role of radionuclide generator
Definition
Constitution
Examples
Role of radionuclide generator
Properties/ requirements
Conclusion

4. “A radionuclide generator...
..can be defined as an effective radiochemical separation of decaying ´parent´ and ´daughter´ radionuclides such that the daughter is obtained in a pure radiochemical and radionuclidic form.
The parent system is called the ´cow´ from which the daughter radioactivity is ´milked´”.
Gobal B. Saha. Fundamentals of Nuclear Pharmacy. 4th ed. Springer, 1998
F. Rösch, F.F. Knapp. Radionuclide generators. Handbook of Nuclear Chemistry, Vol. 4, 2002

5. To ´milk´ the´cow´?

6. Setup

7. Examples Type Generator . System Parent Main nuclide decay T1/2
Daughter Main Application
nuclide emission
Positron emitter Ge /68Ga
 270.8 d EC
1.135 h ß PET
Photon emitter Mo/ 99mTc
2.74 d ß-
6.006 h y SPECT
Particle emitter Sr /90Y
28.5 a ß-
2.671 d ß ERT
In vivo Ni /66Cu
2.28 d ß-

8. Examples Type Generator . System Parent Main nuclide decay T1/2
Daughter Main Application
nuclide emission
Positron emitter 68Ge /68Ga
 270.8 d EC
1.135 h ß PET
Photon emitter Mo/ 99mTc
2.74 d ß-
6.006 h y SPECT
Particle emitter Sr /90Y
28.5 a ß-
2.671 d ß ERT
In vivo Ni /66Cu
2.28 d ß-

9. Examples - 68Ge /68Ga Positron emitter T1/2=1.135 h first in 1996
for imaging myocardial perfusion
for neuroendocrine tumors with [68Ga]DOTATOC
Ga3+ in macrocyclic bifunctional chelator DOTA
DOTATOC has high affinity to somatostatin-receptor in tumors
Ga3+
DOTA = Tetra-aza-cyclo-dodecane-tetraacetic acid
DOTATOC = (DOTA-Phe,Tyr3-Octreotid)

10. Examples - in-vivo generator
Basics: Molecule carriers are labeled with radionuclide parent
accumulation in the desired organ
shorter half-live daughters are produced ´in-vivo´
Diagnostic and therapeutical application
problem: daughter nuclide is released from the labeled tracer and thus its original position

11. Contents Theoretical Background Role of radionuclide generator
Definition
Setup
Examples
Role of radionuclide generator
Properties/ requirements
Conclusion

12. Role of generator in Nuclear Medicine
George de Hevesy´s tracer concept
radionuclides and radioactive molecules are used in nano-molecular concentrations for analysing physiological process in vivo, but have no pharmacologic effect

13. Role of generator in Nuclear Medicine
Why are radionuclide daughters not directly produced in reactors or cyclotrons?

14. The role of generator in Nuclear Medicine - Properties
~95% of nuclear medicine procedures are diagnostic, the rest therapeutic
they take place in hospitals or medical departments of universities
generators provide parents which have long enough half-lives to make them easy transportable
cost, availibility generators provide a continuing source of radionuclides, several applications out of a single generator
separation repeatable, simple, easy to handle, convenient, rapid to use
Def. Nuclear medicine
May have facilities to preparate radiopharmaceuticals
Place of producing does not equal place of diagnostic test

15. The role of generator in Nuclear Medicine - Properties
Conservation of a defined chemical form of parent and daughter
Avoid additional chemical manipulations, breakthrough of parent (toxity)
Expenditure of time to generate the daughter smaller than the parent´s half-live
) No intermediate

16. Special properties for clinical application
Daughter:
-short-lived radionuclides: could be given in larger dosage, minimal radiation but excellent results
Seperation should result in high yield
To minimize the radiation in short period of time….> daughter nuclide should decay to another long-live or even stable isotope
Radionuclide‘s half-live long enough to reach the targeted organ but not being present more than one day
Good tracebility of the daughter nuclide --- half-live, type of radiation and energy
No- carrier added form
-- lead to negligible concentrations---and therefore not invasive

17. Conclusion
Reasonable cost
No- carrier added form
simple
repeatable
on demand
easy transportable
availibility
„Convenient
„Convenint alternative to the cost-intensive production production in reactors and cyclotron“

18. Thanks