Resumo de eventos cient??ficos
Waste management protocols for Iridium-192 sources production laboratory used in cancer treatment
Registro en:
0000-0001-5989-7287
0000-0002-7303-6720
0000-0003-2943-6097
Autor
ROSTELATO, MARIA E.C.M.
SOUZA, CARLA D. de
SOUZA, DAIANE C.B. de
ZEITUNI, CARLOS A.
TIEZZI, RODRIGO
COSTA, OSVALDO L. da
RODRIGUES, BRUNA T.
MOURA, JO??O A.
FEHER, ANSELMO
SORGATTI, ANDERSON
MOURA, EDUARDO S. de
MARQUES, JOSE R. de O.
SANTOS, RAFAEL M. dos
KARAM JUNIOR, DIB
INTERNATIONAL CONGRESS OF THE INTERNATIONAL RADIATION PROTECTION ASSOCIATION, 14th
Resumen
Introduction: Brachytherapy is a form of treatment that uses radioactive seeds placed in
contact or inside the region to be treated, maximizing the radiation dose inside the targeted areas.
Iridium-192 is being used in brachytherapy since 1955. It presents emission energy in the ???therapy region???
(370keV) and is easily produced in a nuclear reactor (191Ir (n, ??) ??? 192Ir). Wires are an iridium-platinum
alloy with 0.36 mm diameter and they can be cut in any needed length. They can be used in several types
of cancer. The linear activity is between 1 mCi/cm (37 MBq/cm) and 4 mCi/cm (148 MBq/cm) with
variations of 10% in 50 cm maximum. This activity values classified the treatment and low dose rate (0,4
?? 2 Gy/h). The propose of this work is to present a waste management system in a cancer treatment
radioactive sources production laboratory. Methodology and Results: The solid waste is previously
characterized in the analysis phase. The contaminants are already known and they are insignificant due
to their fast half- life. The iridium-192 half-life is 74.2 days, classified as very short half-life waste. The
waste activity is adds to 8mCi (2.96x108 Bq) per wire. According to the CNEN-NN 6.08 standard, that
presents the discharge levels, the limit is 1 kBq.kg-1 (2.7x10-5 mCi.kg-1). The radioactive waste generated
during the I192 wires production has a weakly activity of 9.7 GBq.g-1. According to the standards, this
activity is too high to be discarded into the environment. The waste must be managed following
the ALARA principal using the R&R (retain e retard) system, that means, temporary storage and posterior
discharge. Since every 4 months, maintenance is performed inside the hot cell used for production, the
waste must be removed. Using the equation: ???? =
????
??
(1 ??? ?????????t), the total calculated activity is 1.68 x 1016
Bq and 4.8 g mass at the end of each 4 months period. This amount is stored inside a shielding device
that has 212.37 cm3 volume. The waste will take 9.8 years (calculated by ???? = ????0(?????????t)) to decay to the
discharge levels. To store 30 devices during 10 years, a space with 6,370 cm3 is necessary. The
laboratory has enough space for this storage. Thus, the radioactive waste management can be performed
through the R&R (retain and retard) system safely.