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Brookhaven National LaboratoryBrookhaven National LaboratoryNuclear Chemistry Summer SchoolNuclear Chemistry Summer SchoolSarah WeßmannSarah Weßmann
07/27/200607/27/2006
Radionuclide generators for Radionuclide generators for Nuclear MedicineNuclear Medicine
Overview Overview
Theoretical BackgroundTheoretical Background DefinitionDefinition SetupSetup ExamplesExamples
Role of radionuclide generatorRole of radionuclide generator Properties/ requirementsProperties/ requirements ConclusionConclusion
Overview Overview
Theoretical BackgroundTheoretical Background DefinitionDefinition ConstitutionConstitution ExamplesExamples
Role of radionuclide generatorRole of radionuclide generator Properties/ requirementsProperties/ requirements ConclusionConclusion
“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
Type Generator . System
Parent Main nuclide decay T1/2
Daughter Main Applicationnuclide emissionT1/2
Positron emitter 68Ge /68Ga 270.8 d EC 1.135 h ß+ PET
Photon emitter 99Mo/ 99mTc 2.74 d ß- 6.006 h y SPECT
Particle emitter 90Sr /90Y 28.5 a ß- 2.671 d ß- ERT
In vivo 66Ni /66Cu 2.28 d ß- 1.135 h ß+ PET
Examples Examples
Type Generator . System
Parent Main nuclide decay T1/2
Daughter Main Applicationnuclide emissionT1/2
Positron emitter 68Ge /68Ga 270.8 d EC 1.135 h ß+ PET
Photon emitter 99Mo/ 99mTc 2.74 d ß- 6.006 h y SPECT
Particle emitter 90Sr /90Y 28.5 a ß- 2.671 d ß- ERT
In vivo 66Ni /66Cu 2.28 d ß- 1.135 h ß+ PET
ExamplesExamples
Examples - Examples - 6868Ge /Ge /6868GaGao Positron emitter
o T1/2=1.135 h
o first in 1996
o for imaging myocardial perfusion
o for neuroendocrine tumors with [68Ga]DOTATOC
N N
N N
HOOC
HOOC COOH
O
NH
R
DOTA = Tetra-aza-cyclo-dodecane-tetraacetic acid
DOTATOC = (DOTA-Phe,Tyr3-Octreotid)
Ga3+ in macrocyclic bifunctional chelator DOTA
DOTATOC has high affinity to somatostatin-receptor in tumors
Ga3+
•Basics: Molecule carriers are labeled with radionuclide parent accumulation in the desired organ shorter half-live daughters are produced ´in-vivo´
Examples - in-vivo generatorExamples - in-vivo generator
•Diagnostic and therapeutical application
problem: daughter nuclide is released from the labeled tracer and thus its original position
Contents Contents
Theoretical BackgroundTheoretical Background DefinitionDefinition SetupSetup ExamplesExamples
Role of radionuclide generatorRole of radionuclide generator Properties/ requirementsProperties/ requirements ConclusionConclusion
Role of generator in Nuclear Role of generator in Nuclear MedicineMedicine
George de Hevesy´s George de Hevesy´s tracer concepttracer concept
radionuclides and radioactive molecules are radionuclides and radioactive molecules are used in nano-molecular concentrations for used in nano-molecular concentrations for analysing physiological process in vivo, but analysing physiological process in vivo, but have no pharmacologic effect have no pharmacologic effect
Role of generator in Nuclear Role of generator in Nuclear MedicineMedicine
Why are radionuclide daughters not directly produced in reactors or cyclotrons?
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
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
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
Conclusion
„Convenint alternative to the cost-intensive production production in reactors and cyclotron“
Reasonable costReasonable cost
repeatablerepeatable
No- carrier added formNo- carrier added form
easy transportableeasy transportableavailibilityavailibility
simplesimple
„„ConvenientConvenient
on demandon demand