Page 40 - PR 2014 2016 03 Applications of Ionizing Radiations

82 Application of Ionizing Radiations | Progress Report

Initially, these dosimeters were submitted to ter, 0.05 mm wall thickness, and 4,5mm long.
two selection steps to choose the dosimeters This work aims to study and develop a seed
more reproducible for the dosimetric analysis. of iridium-192 from a platinum iridium alloy.
The two steps were the selection by the mass No study on the fabrication of these seeds was
of the dosimeters and the reproducibility after found in available literature. It was created a
four irradiation series in a Cobalt-60 irradiator methodology that involved: characterization
(CTR-IPEN). After, the dosimeters were used of the material used in the core, creation of
to the irradiations with Iodine-125 seed, 6711 device for neutron activation irradiation, laser
model, (GE-Healthcare). The irradiations and welding of the titanium coating and testing of
others analysis with Iodine-125 seeds yielded quality control. The result proved the feasibility
the useful values for the determination of the of the method. As a suggestion for future work,
parameters suggested by the AAPM (Amer- studies regarding metrology and dosimetry of
ican Association of Physicists in Medicine): these sources should be carried out, for future
constant of dose rate, geometry function, dose implementation in national scope.
radial function and anisotropy function. The
results showed good agreement with the val-
ues published by the literature, for the same
Iodine-125 model. This fact confirms that the
achieved parameters will be able to be used
for the IPEN-CNEN Iodine-125 seeds dosimetry
and quality control.

Study and development of an iridium-192
seed for use in ophthalmic cancer

Although ocular tumors are not among the
cases with a higher incidence, they affect the
population, especially children. The Institute
of Energy and Nuclear Research (IPEN-CNEN/
SP) in partnership with Escola Paulista de Me-
dicina (UNIFESP), created a project to develop
and implement an alternative treatment for
ophthalmic cancer that uses brachytherapy
iridium-192 seeds. The project arose since
the Escola Paulista treats many cancer cases
within the Unified Health System (SUS) and
also because of the research experience of
sealed radioactive sources group at IPEN. The
methodology was developed from the avail-
able infrastructure and the experience of the
researchers. The prototype seed presents with
a core (192-iridium alloy of iridiumplatinum
iridium platinum) of 3.0 mm long sealed by a
capsule of titanium of 0.8 mm outside diame-

Instituto de Pesquisas Energéticas e Nucleares