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Iridium-192 seed development for ophthalmic cancer treatment
2011 - ROSTELATO, M.E.C.M.; MATTOS, F.R.; ZEITUNI, C.A.; SOUZA, C.D.; MOURA, J.A.; MOURA, E.S.; FEHER, A.; COSTA, O.L.; PELEIAS JUNIOR, F.S.; MARQUES, J.R.O.; BELFORT NETO, R.
Considered a public health problem in Brazil, cancer is the second leading cause of mortality by disease, representing 13.2% of all deaths in the country [1]. Ophthalmic brachytherapy involves inserting an acrylic plate with radioactive material in the eyes of a patient for treatment of ocular tumors. This work is a partnership between Escola Paulista de Medicina - UNIFESP and the Instituto de Pesquisas Energéticas e Nucleares - IPEN for development and implementation of a cheaper therapeutic treatment for ophthalmic cancer with a iridium-192 source, to attend a greater number of patients. Iridium-192 is produced in nuclear reactor. It has a half-life of 74.2 days and decays by beta emission with average energy of 370 keV.[2,3]. The seed will be a platinum-iridium alloy core (80/20), encapsulated in a titanium tube [4]. This project will be divided into the following steps: characterization of materials by FRX (X-ray fluorescence) e EDS (Energy Dispersive Spectroscopy); iridium irradiation in the nuclear reactor IEA-R1; sealing of iridium-192 seed; leakage tests of iridium-192 source in accordance with standard ISO-9978 (radiation protection- Sealed radioactive sources- Leakage test methods) [5]; metallographic tests and measure the activity of the source. The evaluation for use in the ophthalmic treatment of cancer will be made later.
Improvements in the quality control of iridium-192 wire used in brachytherapy
2011 - COSTA, OSVALDO L.; ZEITUNI, CARLOS A.; ROSTELATO, MARIA E.C.M.; MOURA, JOÃO A.; FEHER, ANSELMO; MOURA, EDUARDO S.; SOUZA, CARLA D.; SOMESSARI, SAMIR L.
Brachytherapy is a method used in the treatment of cancerous tumors by ionizing radiation produced by sources introduced into the tumor area, this method seeks a more direct attack to the tumor, thereby maximizing the radiation dose to diseased tissue while minimizing the dose to healthy tissues (1). One of the radionuclides used in brachytherapy is iridium-192. The Radiation Technology Center (CTR) of the Nuclear and Energy Research Institute (IPEN) has produced commercially, since 1998, iridium-192 wires used in low dose rate (LDR) brachytherapy (2). To produce this radionuclide, firstly a iridium-platinum wire is irradiated in the nuclear reactor IEA-R1 for 30 hours with a neutron flux of 5 x 1013 ncm-2s-1, the wire is left to decay by 30 days to remove the main contaminants and then goes through a quality control before being sent to the hospital. In this quality control is checked the radiation homogeneity along each centimeter of the wire (3). To implement this procedure is used a device consisting of an ionization chamber surrounded by a lead shield with a small 1 cm wide slit, linked to the ionization chamber is a voltage source and a Keithley 617 electrometer, 2 minutes is the range used to measure the charge by the electrometer. The iridium wire is considered in accordance when there is no variation greater than 5% between the average measures and the maximum and minimum values. However, due to design features of the measurement system, the wire may appear to the detector through the slit in larger sizes than the ideal, improperly influencing the final quality control. This paper calculates the difference in size of these variations in profile and their influence on the final count, it compares the actual values obtained and describes the improvements made in quality control procedures that provided more accurate measurement data, analyzes the results and suggests changes in devices aimed at further improving the quality control of iridium-192 wires produced at IPEN and used in hospitals in Brazil.
Waste management protocols for Iridium-192 sources production laboratory used in cancer treatment
2016 - 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, JOÃO A.; FEHER, ANSELMO; SORGATTI, ANDERSON; MOURA, EDUARDO S. de; MARQUES, JOSE R. de O.; SANTOS, RAFAEL M. dos; KARAM JUNIOR, DIB
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, γ) → 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 à 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: 𝐴 = 𝐿 λ (1 − 𝑒−λt), 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 𝐴 = 𝐴0(𝑒−λt)) 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.
Waste management protocols for iridium-192 sources production laboratory used in cancer treatment in Brazil
2017 - ROSTELATO, M.E.C.M.; SOUZA, D.C.B.; SOUZA, C.D.; ZEITUNI, C.A.; VICENTE, R.; COSTA, O.L.; RODRIGUES, B.T.; MOURA, J.A.; FEHER, A.; MOURA, E.S.; MARQUES, J.R.O.; CARVALHO, V.S.; NOGUEIRA, B.R.
Objective: The iridium-192 wired sources production results in radioactive waste that needs to follow the guidelines. The aim of this study is to do a radioactive waste management of wastes from iridium-192 sources production laboratory used in cancer treatment in Brazil. Methods: The wire is acquired in an alloy form with 80% platinum and 20% iridium encapsulated with 100%. Electronic microscopy, X-ray fluorescence, and posterior iridium neutron activation (to determine contaminants) are performed to ensure quality. A 50-cm twisted wire is placed in an aluminum tube. The tube is sealed and place inside the reactor irradiator system and is left for decay during 30 hours to wait for the others undesired activation products to decay. The wire is prepared for treatment with 48 cm length with 192 mCi maximum activity. All the equipment use inside the hot cell must be calibrated every four months. All the waste must be removed from the hot cell. 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 reminiscent activity is 8mCi. Conclusion: The radioactive waste generated during the I192 wires production is solid, was a short half-life and a weakly activity of 9.7 GBq.g-1. According to the standards, this activity is too high to be discarded into the environment (limit 10 Bq.g-1). The waste must be managed by the R&R (retain e retard) system.
Brazil radioactive sources production for cancer treatment
2016 - ROSTELATO, MARIA E.; SOUZA, CARLA D.; ZEITUNI, CARLOS A.; MOURA, JOAO A.; MARQUES, JOSE R.O.; COSTA, OSVALDO L.; FEHER, ANSELMO; RODRIGUES, BRUNA T.; SOUZA, DAIANE C.B. de; PELEIAS JUNIOR, FERNANDO S.; SORGATTI, ANDERSON; MOSCA, RODRIGO; MOURA, EDUARDO S. de; ABREU, RODRIGO T.; SOUZA, RAQUEL V. DE; NOGUEIRA, BEATRIZ R.
The modality, known as brachytherapy, was performed in Brazil by only a hand full of hospitals at an extremely high cost. For producing new sources, five major areas must be considered: 1) source production: nuclear activation and/or radiochemical reaction; 2) welding; 3) Quality control: leakage tests; 4) Dosimetry and metrology; 5) Operational procedures; 6) validation studies. To perform all steps, a multidisciplinary team works together to overcome difficulties. - Iridium-192 pellets: In Brazil there are 140 machines with pellets that replacement every 5 years. Our new production line has assembly, welding and quality control hot cells. - Iridium-192 wires: Produced since 1999. The wire is activated at IPENs IEA-R1 reactor for 30 hours with 5x1013 n/cm-2.s-1 neutron flux resulting in 192 mCi maximum activity. - Iridium-192 seed: New seed for ophthalmic cancer treatment. The irradiation device presented 90% activity homogeneity. We are still testing in-vivo. - Iodine-125 seeds: Largely used in low dose brachytherapy. I-125 binding yield achieved with our new reaction was 80%; Laser welding presented 70% efficiency. Approved in all leakage tests. - Other ongoing projects: Veterinary brachytherapy, Waste management, Radionecrosis healing with laser, calibrations sources production, linear accelerator calculations for hospitals, sources with polymeric matrix Our Iodine-125 seeds will be available in 2018. All other projects are advancing. We will continue to develop new products hoping to help the Brazilian population fight against cancer. For producing new sources, five major areas must be considered: 1) source production: nuclear activation and/or radiochemical reaction; 2) welding; 3) Quality control:eakage tests; 4) Dosimetry and metrology; 5) Operational procedures; 6) validation studies. To perform all steps, a multidisciplinary team works together to overcome difficulties
Surface coating and study of metallic cores for radioactive sources production used in cancer treatment
2016 - ROSTELATO, M.E.C.M.; SOUZA, C.D.; ZEITUNI, C.A.; MATTOS, F.R.; MARQUES, J.R.O.; MOURA, J.A.; FEHER, A.; COSTA, O.L.; SOUZA, D.C.B.; TIEZZI, R.; RODRIGUES, B.T.; KARAM JUNIOR, D.
Developing new and innovative treatments for cancer is an urgent matter. The National Institute of Cancer estimates that Brazil will have 576,000 new cases of the disease in 2015. Our research group is developing new radioactive seeds to be use in radiotherapy procedures since the early 2000’s. We present the surface study and research for two of our major projects: iodine-125 seeds for prostate, brain and eye cancer treatment and iridium-192 for eyecancer treatment.
Development and characterization of iridium-192 seeds for brachytherapy treatment of ocular tumors
2014 - PELLEIAS JUNIOR, F.S.; ZEITUNI, C.A.; SOUZA, C.D.; ROSTELATO, M.E.C.M.; MATTOS, F.R.; BENEGA, M.A.G.; RODRIGUES, B.T.; TIEZZI, R.; OLIVEIRA, T.B.; FEHER, A.; MOURA, J.A.; COSTA, O.L.
Study and development of a iridium-192 seed for use in ophthalmic cancer
2014 - ROSTELATO, M.; SOUZA, C. de; PELEIAS JUNIOR, F.S.; ZEITUNI, C.A.; MATTOS, F.R.; BENEGA, M.A.G.; MOURA, J.A.; FEHER, A.; COSTA, O.L.
Study and development of a iridium-192 seed for use in ophthalmic cancer
2014 - ROSTELATO, M.; SOUZA, C. de; PELEIAS JUNIOR, F.S.; ZEITUNI, C.A.; MATTOS, F.R.; BENEGA, M.A.G.; MOURA, J.A.; FEHER, A.; COSTA, O.L.
Influence of the profile of iridium-192 wire in measurements of quality control for use in brachytherapy
2013 - COSTA, OSVALDO L.; ZEITUNI, CARLOS A.; ROSTELATO, MARIA E.C.M.; MOURA, JOAO A.; FEHER, ANSELMO; MOURA, EDUARDO S.; SOUZA, CARLA D.; SOMESSARI, SAMIR L.; PELEIAS JUNIOR, FERNANDO S.; MATTOS, FABIO R.