INCT Sub-Projects
In this section are the participant institutions abstracts.
Area of interest: Radiation Protection, Radiodiagnostic and Radiotherapy
The Calibration Laboratory of IPEN, since 1977, performs calibrations at radiation protection, radiotherapy and diagnostic radiology levels. The types of tested instruments, which are manufactured in Brazil and in other countries, may vary from very simple electronics and designed survey meters until sophisticated instruments (enclosed clinical dosemeters) with audacious and modern electronics. Moreover, the recommendations and codes of practice to be applied to the Standard Dosimetry Laboratories are revised and brought up to date continuously, incorporating new quantities and methodologies. In such a way, this Calibration Laboratory must always develops studies of implementation of the techniques in order to renew the existing methods and infrastructure, and establish new methods considering the diversity of equipment in the market and all the recommendations that have to be applied. The quality system establishment the following the IEC/ISO/NBR 17025 norm, for the Calibration of Portable Monitors with Radiation Gamma, showed the importance of keeping the processes and procedures controlled and up to date. Therefore, it is necessary, also, the extension of the object of this quality system in order to incorporate the other processes applied to instruments calibration, including therapy and diagnostic radiology methods.
Area of interest: Radiation Protection
Nowadays the benefits of the use of ionizing radiation are unquestionable, mainly in Medicine, industry, research and power generation. However, to obtain these benefits there are always continuous exposure of people not only involved routinely, but also in case of accidents. On the other hand, it is known that exposure to ionizing radiation causes early and late deleterious biological effects. Presumably there is always some risk to irradiated individuals, even with extremely low doses. At this point, Radioprotection, the field of Science in which protection of living being and environment against the adverse effects of radiations is studied, should be considered. An overall objective of Radiological Protection is to balance the risks and benefits, in a way that the benefits must be always larger than the risks. To achieve the goal, one important question to be considered is the dosimetry of radiation and the dissemination of radiation knowledge not only to workers occupationally exposed to ionizing radiation but also to opinion makers as journalists and high school teachers.
Area of interest: Radiodiagnostic
The quality assurance control in the medical radiology required by the Brazilian legislation foresees the quality control of equipment and images in order to guarantee the success in the diagnostic and fulfill the principles of the radiologic protection. Systematic verifications of the performance of that equipment are necessary to keep up the quality and medical procedure safety. The development of the equipment that allows the control of the parameters related to the X ray beam qualification, as well as assess the doses through the use of detectors type ionization chamber, will supply a market demand strictly dependent on overseas instrumentation, without local, fast and cheaper maintenance. The goal is to develop an instrument that can be applied to the radiodiagnostic (50 to 150 kV) for parameters verification: peak voltage (kVp), peak practical voltage (kVpp), wave form, ripple, type of generator, effective time, total time, half value layer (HVL) and air kerma rate. This should be the first initiative for the national production of a family of multifunctional instruments, complying with the technical Brazilian standards ABNT, NBR and IEC 60601.
Area of interest: Radiotherapy and Radiodiagnostic
The objective of this study is to determine the spectra of different radiation systems used in the calibration laboratories and in clinical practice in diagnostic radiology and radiotherapy in order to investigate the differences between these spectra and their influence on the dosimetric quantities of practical use. The spectra will be measured on a direct way using scintillator and semiconductor detectors. From the measured spectra will be estimated several dosimetric quantities such as air kerma, absorbed dose and other parameters of practical interest as a half value-layer, homogeneity coefficient, mean energy among others. The validation of these estimates will be held from measurements made with ionization chambers and thermoluminescent dosimeters.
Area of interest: Radiotherapy and Radiodiagnostic
Although the application of ionizing radiation in medicine has been established for over a century, through technological developments, new techniques are implemented continuously. Despite great advances, differences in doses for the same type of diagnostic procedure have been reported in many countries. There is therefore a high potential for reduction of doses in patients, through optimization of protocols and procedures, without the loss of diagnostic information. In the case of treatments, due to their high complexity, if they aren’t planned and controlled properly, they may cause severe damage to the patient. Thus, the delivery of the dose during treatment should be optimized, verified, and compared to the established planning. This project has as objective to establish a national program of assessment of doses in diagnosis, coupled with the quality of the image, and in therapy, coupled with the treatment planning, through the development of appropriate procedures and protocols for this assessment. Another goal, not less important for the execution of this project, is the training and development of the personnel involved in each step, contributing to training and specialization of human resourses.
Area of interest: Radiodiagnostic
The establishment of a basic metrological structure has been for more than 10 years one aim of the Development Centre of Nuclear Technology (CDTN) in order to provide reliability in dosimetry of x-rays, beta and gamma radiations. Radiation sources and facilities have been acquired and implemented by drawing efforts and resources for the attendance of the metrological needs in radiodiagnostic, radioprotection, radiotherapy and nuclear medicine practices. Special attention has been given to metrology in diagnostic radiology due to the enforcement of national legal requirements for radiological protection and radiographic image quality by Minas Gerais authorities. Experimental systems for x-ray metrology that include standard dosimeters and calibration methodologies were built installed and are to be strengthened. The available infrastructure and the exchange of knowledge and experience among Brazilian Metrology Laboratories have built a basic framework for research and development projects that aimed reliable patient dosimetry and quality control of images in Minas Gerais radiodiagnostic services. This project will draw the resources to strength the metrological basis, to improve the dosimetry techniques and to upgrade the procedures for radiographic image analysis for medical and dental radiology, computerized tomography and conventional and digital mammography services. The results of the project are to be used for research, services to the community and education.
Area of interest: Radiodiagnostic
The utilization of radiopharmaceuticals in medicine is increasing significatively in the last years. The optimization of the procedures should be observed in order to minimise patient, worker and public risks. Since there are no doses limits to patients in medical practice, the reference levels must be observed. However, there aren’t Brazilian reference levels established for diagnostic procedures in nuclear medicine and scarce information is available about the administered activities. In therapeutic applications, the values of administered activity could be reduced by detailed and specific absorbed dose calculations for each patient. Besides, the only way to guarantee that the correct activity is administered to patient is by using the calibrator of radionuclide properly. The intercomparisons programs are useful because they evaluate the equipment accuracy and the measurement procedures, indentifying eventual mistakes. Another relevant aspect is the quality of the radiopharmaceutical administered to patients. In general, the tests to verify the quality of the radiopharmaceuticals are not performed at the nuclear medicine centers and the survey of the data concerning the quality of radiopharmaceuticals is very important for the evaluation of the efficiency of the utilized procedures as well as in the accomplishment of the radiological protection principles applied to nuclear medicine.
Area of interest: Radiation Protection
The utilization of ionizing radiation in quotidian life increases each day. If the first major applications were in medicine, nowadays, it is possible to find ionizing radiation application in most industrial areas. To allow the widely use of ionizing radiation, it is necessary to develop equipments and methods of radiation detection. Detectors of most various forms, composition and characteristics are necessary to cover all kind of ionizing radiation utilization. Some of them require ultra-sensitive detector, others require a size bigger than usual. Rarely, natural occurring materials have all the necessary characteristics to be used as a radiation detector. Therefore, the study and improvement of dosimetric materials are very important, guarantying the benefices of nuclear technology in areas such as health, safety and natural environment. In medicine, the quality control tests on diagnostic imaging equipments require usually the utilization of phantoms. The composition and geometry of those phantoms varies according to the technique. However, mostly, they are really simple and made of materials such as acrylic and aluminum. Even though those phantoms are not very sophisticated technologically, they are generally obtained abroad. In Brazil, there is only one company manufacturing phantoms for quality control on mammographic equipments. The dosimetric materials developed and/or enhanced will be characterized and the methodologies of utilization of them in various ionizing radiation applications will be evaluated. Besides, the research area and the members of the group were chosen considering projects that already exist in the institutions involved in this project. Therefore, the main goal of the project will be stimulate the cooperation among the institutions, aiming the achievement of good results together.