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International Workshop PSD-11 Delft
Clive Naidoo (PhD Chemistry)
Dept Head: Radionuclide Production
iThemba LABS
South Africa
Electronic and Information Services
Accelerator Infrastructure
Directorate
HR, Finance & General Admin
Technical Support & Site Services R
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iThemba LABS Structure
RPD OBJECTIVES
• To produce radiopharmaceuticals for the benefit of the
South African Nuclear Medicine community.
• To produce longer-lived radionuclides for the export
market.
• Research & Development and Training Program.
iThemba LABS Layout
Separated-Sector Cyclotron FacilitySeparated-Sector Cyclotron Facility
0 10 20 m
beambeamswingerswinger
SSCSSC
SPC1SPC1SPC2 SPC2
Polarized ion sourcePolarized ion source
ECR ion sourceECR ion source
RadioisotopeRadioisotope production production
Neutron therapyNeutron therapy
SpectrometerSpectrometerTarget vaultsTarget vaults
electronicselectronics electronicselectronics
Proton therapyProton therapy
Separated Sector Cyclotron (200 MeV)
RPD beam time allocation
Monday night 17h00 to 7h00 (14 h)
Tuesday night 17h00 to 7h00 (14 h)
Wednesday night 17h00 to 7h00 (14 h)
Thursday night 17h00 to 5h00 (12 h)
On average 54 h / week (32%)
RPD beam time allocation
with beam splitter
Radionuclide Half-Life (hours)
Nuclear Reaction Radiopharmaceutical
Product
Main Use
18F 1.83
15O(p,n)
18F
18F-FDG Glucose metabolic
studies 67
Ga 78.3 Zn(p,xn)67
Ga
Ge(p,x)67
Ga
67Ga-citrate Localization of
certain tumours and inflammatory
regions 81
Rb/81m
Kr 4.58 Kr(p,xn)81
Rb 81
Rb/81m
Kr generator Lung ventilation studies
123I 13.2 127
I(p,5n)123
Xe 123
I
123I-sodium iodide
123I-mIBG
Thyroid studies
Localization of certain tumours
such as neuroblastoma,
pheochromocytoma 68
Ge/68
Ga
generator
68Ge = 271 d
68Ga = 68 min
69Ga(p,2n)
68Ge
68Ga –DOTA-peptides Typically detection
of neuroendocrine tumours
iThemba LABS Products produced
under cGMP principles
Radionuclide Half-Life (days/years)
Nuclear Reaction Main Use
82Sr 25 days Rb(p,xn)
82Sr Used to manufacture
82Sr/
82Rb
generators 68
Ge 271 days Ga(p,xn)68
Ge Used to manufacture 68
Ge/68
Ga generators and calibration sources for
PET CT scanners 88
Y 106.6 days Sr(p,xn)88
Y Non –medical application –calibration sources
109Cd 453 days Ag(p,xn)
109Cd Non-medical application-calibration
sources 22
Na & 22
Na positron sources
2.602 years Mg(p,n)22
Na Used in Material Sciences -Positron Annihilation Studies
iThemba LABS other products
Horizontal Beam Target Station (HBTS)
Produce: 67Ga, 123I, 81Rb, 68Ge, 82Sr, 22Na, 88Y, 57Co and 109Cd
HBTS Target and target holders
66 MeV proton beam with an intensity of ~90 µA
Vertical Beam Target Station (VBTS)
VBTS Tandem targets 66 MeV proton beam with an intensity of ~250 µA
VBTS Thick Target Holders
VBTS Tandem targets
Produce in Tandem 82Sr/68Ge and 22Na/68Ge
18F- Bombardment Station
18F Target Station (66 MeV to 18 MeV)
Enriched water target
Target Control System
Beam Splitter
RPD Control Room
Automated Transport System Control systems such as cooling systems (water and helium), interlocking systems
and transport system
18F-Automated Chemical
Processing Hot Cells
Chemical Processing Facilities
Manual Manipulator Hot Cells (two banks of 7)
3 Independent clean rooms
68Ge/68Ga 18F-FDG
123I /67Ga
Dispensing facilitiesnts
Comecer Hotcells & Timothea Dispensing Facilities
Quality Control Facilities
GC
Capintec Ionisation Chamber
HPLC
Quality Control Microlab
Sterility and endotoxin testing
QC Raw material
Packing and Dispatch
As per IATA Regulations
Tandem target for the production of 22Na and 68Ge
65.762 MeV 36.635 MeV 62.579 MeV 61.476 MeV
20 mm
40.013 MeV 38.444 MeV 36.866 MeV 34.364 MeV 2.364 MeV
66 MeV
protons
Mg material: 99.99% (15 g)
Chemical Processing
A magnesium target (ca 15 g, 12 mm thick, 20 mm diameter) is bombarded for several weeks
with a 66 MeV proton beam at a beam current of 80 μA (in the higher energy window 61.5 →
40.0 MeV). [Generally production rate is 1 mCi / h).
The target is dissolved in 3.0 M citric acid and then adjusted to obtain a 0.2 M citric acid - 0.6
M TEA - 80% methanol solution.
The solution is pumped through a column containing 10 g of the macroporous cation
exchanger AG MP – 50.
Washing solutions: 0.2 M citric acid - 0.6 M TEA - 80% methanol, followed by 0.1 M EDTA -
0.6 M TEA. The resin is then converted to the ammonium form with 1.0 M ammonia – 80%
methanol and 22Na is eluted with 1.0 M ammonium carbonate (100 ml) passing through 10 g of
the chelating resin Chelex 100 (in the ammonium form) to remove the last traces of
magnesium and other elements.
The eluate is heated in a conical titanium vessel to evaporate the ammonia and water. 22Na is
obtained as the carbonate salt in a small volume.
All reagents are purified to remove sodium prior to the ion exchange separation
Final Specification: >800 Ci 22Na / g
22Na Chemical Processing hot cell panel
The specified amount of 22Na carbonate solution is dispensed from the bulk vial and placed in a V-vial and
evaporated to about 20-30 µl. Final activity check is done with the Capintec Ionisation Chamber.
The rear part of the capsule is clamped in a holder with the post facing upwards and level.
The 22Na is then transferred, in 10 μl volumes, into the tantalum cup with a semi-automated dispensing
apparatus. This is evaporated to incipient dryness, before the next volume is dispensed.
When all the activity of 22Na has been transferred into the cup, the front part of the capsule is loosely
screwed onto the rear part.
The capsule is finally sealed to a defined torque value (20 Nm) using a special holder to clamp the capsule
tightly.
The external surface of the capsule is washed with methanol and then rinsed with deionised water.
The capsule is dried and a smear test is done.
The source is then placed under vacuum for 24 h to ensure integrity of the capsule.
The washing step is repeated and another smear test is done after the vacuum test.
The positron capsule is then packed into a lead pot, the lead pot is sealed and finally packed in a container
for shipment to the user.
Capsule Dispensing
Positron Capsule
Dispensing apparatus
Holder to seal the capsule
Apparatus for vacuum testing
HPGe detector for final measurements
Na-22 sales and forecasts
Limited beam time for the irradiation of Mg targets at iThemba LABS.
Alternative company’s that could produce 22Na does not meet iThemba
LABS product specification of >800 Ci 22Na / g for large sources.
Alternative company’s needed to irradiate the Mg target material and for
iThemba LABS to do the chemical processing, not economical viable
(cost of irradiation US$ 6000 / mCi 22Na).
The production of sources is limited to a maximum of 50 mCi for the ease of
handling and to minimise radiation exposure to staff .
NB:
Upon receiving the larger sources from iThemba LABS, just do your smear
tests as required by your RPO and install.
Production Challenges
