RRFM 2009 Transactions - European Nuclear Society

2. Methods
2.1 Reactor produced radioisotopes at IPEN – brief story
The Reactor produced radioisotope program started at IPEN in 1959 with the production of
131 I and since then all the efforts were made towards the development of methods for the
production of the desirable radioisotopes. Since 1981 IPEN produces and distributes 99m Tc
generators with imported fission-produced 99 Mo and in-house developed technology of
chromatographic alumina based generators. In 1996 IPEN started a project aiming the
nationalization of the production of 99 Mo through the 98 Mo(n,γ) 99 Mo reaction and developing
the MoZr gel generator technology. The technology was developed but the Reactor could not
reach the power required for the production, 5 MW. However, this project made it possible to
upgrade the Reactor power to 3.5 MW and nowadays it is possible to produce at least 50%
of the Brazilian demand of 131 I. Since 1995 IPEN produces all 153 Sm required in Brazil, and
viability studies were performed towards the production of 166 Ho, 177 Lu and the 188 W- 188 Re
generator. Several tracers were produced in order to help the development of
radiopharmaceutical production methods and among them it can be reported the use of
122 Sb, 124 Sb, 88 Y and 85 Sr.
2.2 Irradiations
All irradiations for the routine production and for the research were performed at the IEA-
R1m reactor at IPEN-CNEN/SP, a pool type reactor using LEU as fuel material, with power
varying from 2 to 5 MW. All the targets were irradiated inside aluminium holders either
directly or inside quartz tubes. A Beryllium irradiator was specially fabricated for high power
irradiations of MoO 3 and TeO 2 targets.
2.3 Routine Production
Nowadays two radioisotopes are routinely produced using IEA-R1m Reactor: 153 Sm and 131 I.
153 Sm, a β - emitter with a half-life of 46 hours is produced through the reaction
152 Sm(n,γ) 153 Sm, irradiating a target of Sm(NO 3 ) 2 enriched in
152 Sm. The target is
encapsulated inside a quartz tube and irradiated for 24-48 hous, depending on the demand.
Two main radiopharmaceuticlas are further prepared with 153 Sm: 153 Sm-EDTMP used bone
pain palliation and 153 Sm-hidroxiapatite, used for radiosinoviortesis.
131 I, a β - emitter with a half-life of 8 days is produced through the indirect reaction
130 Te(n,γ) 131 Te→ 131 I irradiating pressed TeO 2 targets inside an aluminium holder. The targets
are irradiated at least for 2 cycles of 64 hours inside the Be irradiator. The separation
between the irradiated target and 131 I is performed by the dry distillation technique. This
radioisotope can be used to prepare radiopharmaceuticals for both diagnose and therapy
uses. The radiopharmaceuticals are: 131 I-Iodide, 131 I-MIBG, 131 I-Lipiodol and 131 I-Hippuran.
2.4 Viability Studies
Viability studies have been performed for the production of 3 important radioisotopes for
Nuclear Medicine: 166 Ho, 177 Lu, 188 W.
166 Ho is a β - emitter with a half-life of 26.8 hours and is produced through the reaction 165 Ho
(n,γ) 166 Ho. Targets of Ho 2 O 3 were irradiated inside quartz tubes in selected positions of the
Reactor. After the irradiation the samples were dissolved and the activity produced evaluated
by γ ray spectroscopy. The main use of 166 Ho is the labelling of ion exchange resins as
potential agents for liver cancer therapy [2].
177 Lu is a β - emitter with a half-life of 6.7 days and is produced through the reaction 176 Lu (n,γ)
177 Lu. Targets of Lu 2 O 3 were irradiated inside quartz tubes in selected positions of the
Reactor. After the irradiation the samples were dissolved and the activity produced evaluated
by γ ray spectroscopy. One 177 Lu based radiopharmaceutical is currently produced at IPEN,
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