# Presentation: 049872

## Brookhaven National Laboratory
Nuclear Chemistry Summer School
Sarah Weßmann

07/27/2006

**Nuclear Chemistry Summer School**
**Sarah Weßmann**
**07/27/2006**

- Radionuclide generators for Nuclear Medicine

## Overview 

- Theoretical Background
- Definition
- Setup
- Examples
- Role of radionuclide generator
- Properties/ requirements
- Conclusion

## Overview 

- Theoretical Background
- Definition
- Constitution
- Examples
**Role of radionuclide generator**
- Properties/ requirements
- Conclusion

## “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*

## To  ́milk ́ the ́cow ́?

## Setup

## Examples 

| Type              Generator                                                                  .                      System |   Parent             Main   
  nuclide            decay
   T1/2 | Daughter   Main       Application
nuclide     emission
T1/2 |
| --- | --- | --- |
| 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       Application
nuclide     emission
T1/2 |
| --- | --- | --- |
| 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 - 68Ge /68Ga

-  Positron emitter
-  T1/2=1.135 h
-  first in 1996
-  for imaging myocardial perfusion
-  for neuroendocrine tumors with [68Ga]DOTATOC

**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+

## 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

## Contents 

- Theoretical Background
- Definition
- Setup
- Examples
**Role of radionuclide generator**
- Properties/ requirements
- Conclusion

## 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

## Role of generator in Nuclear Medicine

**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

**Notes:**
Def. Nuclear medicine
May have facilities to preparate radiopharmaceuticals
Place of producing does not equal place of diagnostic test

## 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
**    **

**Notes:**
) No intermediate

## 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**

**Notes:**
-- lead to negligible concentrations---and therefore not invasive

## Conclusion

- „Convenint alternative to the cost-intensive production production in reactors and cyclotron“

- Reasonable cost

-  repeatable

- No- carrier added form

- easy transportable

- availibility

- simple

- „Convenient

- on demand

## Thanks