Radiopharmaceutical
Production
Radionuclide Transfer
Transfer Considerations
STOP
RadionuclideTransfer
•
•
•
•
Once the radionuclide is
produced, it is necessary to get it
from the cyclotron to the chemistry
laboratory
If the radionuclide is in the form of
a gas, the transfer can usually be
done with pressure and perhaps a
push gas
In the radionuclide is a liquid, it
must either be pushed with
pressure or transported in some
type of container
If the radionuclide is a solid, then
there must be some transport
container or system to move the
target from the cyclotron vault to
the laboratory for processing.
Contents
• Gas transfer
• Liquid transfer
• Solid target transfer
• Summary
STOP
Gas Transfer
Radiopharmaceutical
Production
Radionuclide Transfer
Contents
Gas transfer
Liquid transfer
Solid target transfer
Summary
The transfer of gases is relatively easy in that
the target gas can usually be moved with a
pressure differential
Pressure
In the simplest scenario,
the gas pressure in the
target is used to push the
gas to the hot laboratory.
An example of this
operation is shown in the
diagram at right. Click
anywhere to start
process. The valve out
of the target will open
and the target will empty
into the vessel. The
pressure will go to
atmospheric
750
15
Closed
Open
Closed
Open
Click again and the exit valve will close, the entrance
valve will open and the target will pressurize.
After that the process can be repeated until all the
activity is out of the target.
STOP
Radiopharmaceutical
Production
Radionuclide Transfer
Transfer from the Cyclotron to
the Chemistry Laboratory
Although the distance to the lab can be quite long, the
transfer of gases is usually easy
Contents
Gas transfer
C-11 transfer line - 60 meters
Liquid transfer
Solid target transfer
Summary
CH3I Synthesis Box
STOP
Liquid Transfer
Radiopharmaceutical
Production
Radionuclide Transfer
•
Contents
Gas transfer
Liquid transfer
Solid target transfer
Summary
•
STOP
The transfer of liquids is
slightly more problematic
since the liquid can break up
in to many tiny droplets and
result in an inefficient transfer.
The picture on the top at right
shows the ideal situation
where there is a single bolus.
The picture below shows the
water breaking up into small
segments which increases the
pressure required to transfer
the liquid and decreases the
efficiency of transfer.
Flow Patterns - Two Phase System
Radiopharmaceutical
Production
Radionuclide Transfer
There several possible types of liquid and gas flow through a small
bore line. These are shown in the diagram below along with the
nomenclature.
Pure Gas Flow
Contents
Gas transfer
Liquid transfer
Annular Flow
Solid target transfer
Summary
Annular-Wavy Flow
Slug Flow
Plug Flow
Bubble Flow
STOP
As we go from pure gas flow, adding more and more liquid, we get
these gradations in the type of flow through the tubing
Long distance F-18 Transfer
Radiopharmaceutical
Production
Radionuclide Transfer
As an example, to transfer liquid over a 60 meter distance,
it was impossible to reliably transfer pure water.
Contents
Gas transfer
Liquid transfer
Solid target transfer
F-18 transfer line
Summary
STOP
Failure Modes
Radiopharmaceutical
Production
Radionuclide Transfer
Contents
Gas transfer
Liquid transfer
Mode 1 – Incomplete Transfer
• The liquid is adhering to the walls of the tubing and the flow
becomes annular
• Contamination of the surface will raise the surface tension of
plastic tubing and lower the surface tension of metal
Solid target transfer
Mode 2 – Line Plugging
• Many small boli at the beginning of the liquid train is worse that
many small boli at the end of the train although the total force
needed to push the liquid through should be the same
• This is probably due to compressibility of gas boli in the liquid
train
Summary
STOP
The water had to be mixed with
acetonitrile to reduce the surface tension
and allow smooth transfer. The
apparatus is shown on the next slide
F-18 Recovery Procedure
Radiopharmaceutical
Production
Radionuclide Transfer
Contents
Gas transfer
Liquid transfer
Solid target transfer
Summary
STOP
Helium in
Vent
• Clean the station
2
• Extract F-18 onto
3 1
CO3-resin with K2CO3 O-18 from target
MeCN
5
soln.
6 4
Plug 6 5 4 rinse 2
• Add MeCN to
1 3
3 1
Vent
2
2
K2CO3 in mixing
Cleaning
MeCN
Resin
Water
vessel
Column rinse 1
• Push through line Cleaning
Mixing
to lab with He flow Water
Recovery
5
5
4 6
6 4
• Rinse with pure
MeCN
O-18
• The column never
recovery
MeCN = acetonitrile
sees MeCN
1
2
3
Transitions from one Flow
pattern to another
Radiopharmaceutical
Production
•
Radionuclide Transfer
Contents
The surface tension
dominated regime refers to
plug, slug and bubbly flow
Gas transfer
Plug Flow
Liquid transfer
Solid target transfer
Summary
•
•
STOP
The shear dominated regime
refers to annular, mist and
annular wavy flow
Annular-Wavy Flow
The surface tension
determines the type of flow
which will occur in the tubing
Low and high surface tension on a metal plate
Radiopharmaceutical
Production
Radionuclide Transfer
Ammonia Synthesis Using
DeVarda’s Alloy
Another example of transfer of liquid is the production of N-13
ammonia using the DeVarda’s alloy method of converting
nitrates into ammonia
Contents
Gas transfer
Water with [13N]Nitrates
13NH
3
Liquid transfer
Solid target transfer
Flow of Helium
Summary
Vent
Sterilizing
Filter
Vacuum
DeVarda’s Alloy
NaOH
STOP
Saline Solution
Solid Target Transfer
Radiopharmaceutical
Production
Radionuclide Transfer
•
Contents
Gas transfer
Liquid transfer
Solid target transfer
Summary
•
STOP
There many target used to
produce radionuclides which
use a solid target. These
targets can be internal targets
which stay inside the cyclotron
during the irradiation or they
can be mounted externally on
the cyclotron or on a beam
line.
After the irradiation, these
targets must be moved to the
hot cells for processing. This
can be done pneumatically or
with a train or other carrier
Metal Target Systems
Radiopharmaceutical
Production
Solid target system for
Siemens RDS 111 cyclotron
Radionuclide Transfer
Contents
Gas transfer
Liquid transfer
Solid target transfer
Summary
Beamline on “OSCAR”
superconducting cyclotron
STOP
Targetry System
Radiopharmaceutical
Production
Cooling Gas
Radionuclide Transfer
Cu Targets
(He: -20C)
Contents
Gas transfer
Liquid transfer
Solid target transfer
Beam
Target Holder
Summary
Cooling Water
Collimator
STOP
Courtesy of Drs. Suzuki &
Fukumura, NIRS
Irradiation Port
Solid Target Transfer
Radiopharmaceutical
Production
Here is an example of a solid target transfer system where the target
is moved using a cart and pulley system. It is mechanically very
simple and therefore quite reliable
Radionuclide Transfer
Contents
Gas transfer
Liquid transfer
Solid target transfer
Solid target
is loaded
into target
holder
Summary
At the end of the chute
is a transport cart
STOP
After irradiation the target is
dropped down a chute
The transport cart is then
moved along a track to the
hot cell for processing
Summary
Radiopharmaceutical
Production
•
Radionuclide Transfer
Contents
Gas transfer
Liquid transfer
Solid target transfer
•
•
Summary
•
STOP
The transfer of radionuclides from the cyclotron to the chemistry
lab can be quite simple or rather complex depending on the
chemical and physical form of the target material.
In gases, transfer is usually very simple with a pressure
gradient being the driving force
In liquids, the surface tension of the liquid and the distance over
which the liquid must be transferred can be significant
confounding factors in the transfer. Care must be taken to
either keep the liquid from breaking up or to rinse the lines with
a second bolus of liquid in order to transfer the maximum
amount of activity.
In solids, the targets are usually transferred using a mechanical
system. The system may be as simple as a holder on a string,
or as complex as a pneumatic transfer system with the ability to
direct the target to several locations.
Return to the main menu