Avaliação da dose no reto em pacientes submetidas a braquiterapia de alta taxa de dose para o tratamento do câncer do colo uterino / Rectal dose assessment in patients submitted to high-dose-rate brachytherapy for uterine cervix cancer

OBJETIVO: O objetivo deste trabalho foi desenvolver um sistema dosimétrico termoluminescente capaz de avaliar as doses administradas ao reto de pacientes submetidas a braquiterapia de alta taxa de dose para o tratamento do câncer do colo uterino. MATERIAIS E MÉTODOS: O material termoluminescente utilizado para a avaliação da dose no reto foi o LiF:Mg,Ti,Na na forma de pó. O pó foi separado em pequenas porções de 34 mg, que foram acomodadas em um tubo capilar. Este tubo foi colocado em uma sonda retal, que era introduzida no reto da paciente. RESULTADOS: As doses administradas ao reto de seis pacientes submetidas a braquiterapia de alta taxa de dose para o tratamento do câncer do colo uterino foram avaliadas com dosímetros termoluminescentes e apresentaram boa concordância com os valores planejados, com base em duas radiografias ortogonais da paciente, imagens ântero-posterior e lateral. CONCLUSÃO: O sistema de dosimetria termoluminescente utilizado no presente trabalho é simples e de fácil utilização quando comparado a outros métodos de dosimetria do reto. Ele mostrou-se eficiente na avaliação da dose no reto de pacientes submetidas a braquiterapia de alta taxa de dose para o tratamento do câncer do colo uterino.

OBJECTIVE: The present study was aimed at developing a thermoluminescent dosimetric system capable of assessing the doses delivered to the rectum of patients submitted to high-dose-rate brachytherapy for uterine cervix cancer. MATERIALS AND METHODS: LiF:Mg,Ti,Na powder was the thermoluminescent material utilized for evaluating the rectal dose. The powder was divided into small portions (34 mg) which were accommodated in a capillary tube. This tube was placed into a rectal probe that was introduced into the patient's rectum. RESULTS: The doses delivered to the rectum of six patients submitted to high-dose-rate brachytherapy for uterine cervix cancer evaluated by means of thermoluminescent dosimeters presented a good agreement with the planned values based on two orthogonal (anteroposterior and lateral) radiographic images of the patients. CONCLUSION: The thermoluminescent dosimetric system developed in the present study is simple and easy to be utilized as compared to other rectal dosimetry methods. The system has shown to be effective in the evaluation of rectal doses in patients submitted to high-dose-rate brachytherapy for uterine cervix cancer.

Study of radiation protection for Elekta medical linear accelerator

The incidence of cancer throughout the world is increasing with the prolonged life expectancy that has resulted from improvements in standards of living. About half of all cancer patients receive radiotherapy, either as part of their primary treatment or in connection with recurrences or palliation. The International Atomic Energy Agency [IAEA] has estimated that approximately 2500 teletherapy machines were in use in 1998 in developing countries and that 10000 such machines may be needed by 2015. The preparation of this Safety paper was initiated as a result of an expected increase in the construction of radiotherapy facilities, and in response to Member States that have requested practical guidance regarding the design and shielding of such facilities[1] In this work, The Harshaw Model 4500 Manual TLD Reader was used for Thermo Luminescence Dosimetry [TLD] by using a set of 20 chips Dosimeter TLD-1 00. A comprehensive set of measurements were performed for five different sites inside and outside the accelerator. The obtained results showed agreement with published data in some location while the results of the working staff site were within the limits of the recommended permissible dose where it was about 0.5 m Sievert per year

Postal dose audits for radiotherapy centers in Latin America and the Caribbean: trends in 1969-2003

Since 1969 the International Atomic Energy Agency and the World Health Organization (along with the Pan American Health Organization, working with countries in Latin America and the Caribbean) have operated postal dosimetry audits based on thermoluminescent dosimetry (TLD) for radiotherapy centers. The purpose of these audits is to provide an independent dosimetry check of radiation beams used to treat cancer patients. The success of radiotherapy treatment depends on accurate dosimetry. Over the period of 1969 through 2003 the calibration of approximately 5 200 photon beams in over 1 300 radiotherapy centers in 115 countries worldwide was checked. Of these audits, 36 percent were performed in Latin America and the Caribbean, with results improving greatly over the years. Unfortunately, in several instances large TLD deviations have confirmed clinical observations of inadequate dosimetry practices in hospitals in various parts of the world or even accidents in radiotherapy, such as the one that occurred in Costa Rica in 1996. Hospitals or centers that operate radiotherapy services without qualified medical physicists or without dosimetry equipment have poorer results than do hospitals or centers that are properly staffed and equipped. When centers have poor TLD results, a follow-up program can help them improve their dosimetry status. However, to achieve audit results that are comparable to those for centers in industrialized countries, additional strengthening of the radiotherapy infrastructure in Latin America and the Caribbean is needed.

Investigación sobre niveles de dosis en exámenes con fluoroscopia gastrointestinal como parte de un programa de control de calidad / An investigation of the levels of radiation exposure in diagnostic examinations involving gastrointestinal tract fluoroscopy

El Servicio de Radiodiagnóstico del Hospital Universitario de la Universidad Federal de Río de Janeiro, juntamente con el Instituto de Radioprotección y Densitometría de la Comisión Nacional de Energía Nuclear, se encuentra desarrolllando programas en el área de garantía de calidad en radiodiagnóstico. Estas actividades contemplan como objetivo importante la optimización de las dosis. Uno de los programas en marcha comprende exámenes de fluoroscopia gastrointestinal. A fin de investigar los niveles de exposición a la radiación fueron realizadas medidas de dosis de entrada en la piel recibidas por pacientes y médicos en exámenes de esofagografía, seriografía y colon, utilizando dosímetros colocados en varias posiciones del cuerpo. En este trabajo se describe la metodología seguida y se muestran los resultados obtenidos hasta el presente. Se hace un análisis del espectro de dosis observadas en pacientes y profesionales, de acuerdo con diversos parámetros tales como ubicación de dosímetros, tiempo de exposición, técnicas empleadas, número de radiografías, etc. También se describen los pasos a seguir con el objeto de concretar la implantación de un programa de control de calidad en los exámenes mencionados