Radioterapia durante a gravidez: aspectos físicos relevantes para a segurança radiológica do feto

• Autor(a) principal: Fernandes, Marco Antonio Rodrigues [UNESP]
• Data de Publicação: 2014
• Outros Autores: Pasqueta, Jéssica [UNESP], Branco, Isabela Soares Lopes [UNESP], Meira, Luiza Leite de Castro [UNESP], Morelli, Humberto Antonio Soares [UNESP]
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://www.rbfm.org.br/index.php/rbfm/article/view/242; http://hdl.handle.net/11449/140615
• topic: Radiotherapy; Pregnancy; Radiation protection; Fetus; Radioterapia; Gravidez; Proteção radiológica; Feto

The work presents the physical and radiological protection procedures involved in radiotherapy performed in patients during pregnancy that contribute to the security and development of the fetus. We analyzed clinical cases studies with confirmed pregnancy undergoing radiotherapy. The study also analyzed the dosimetry protocols specific to different treatment fields considering the absorbed dose in the region estimated fetal through experimental measurements and computer simulations presented in the literature. It is discussed the concepts of radiation fetuses presented in the Report of the AAPM TG 36 focusing on the influence of the use of appropriate shielding and peripheral dose distribution outside the primary radiation field. Studies show no consensus on the threshold dose for fetal exposure, with values ranging between 2 and 25 cGy, depending on gestational age and position within the abdomen. As recommended by the organs of radiological protection in Brazil, the equivalent dose of radiation to the abdomen of pregnant women occupationally exposed should not exceed 2.0 mSv for the entire period of pregnancy. The measurements show that the main factors contributing to the increase in dose to the fetus are: radiation trail head, scattering from the collimator and dispersion by tissue irradiated region to the region surrounding the fetus. The results of research and clinical situations illustrated in reviewed scientific articles indicate that radiotherapy in pregnant patients is feasible, provided that the dose to the fetus is less than the threshold values, which can be achieved by the use of screens and settings fields Radiation appropriate and properly planned by experts who should simulate physical prior to treatment. The work aims to contribute to subsidize the treatment decision in radiotherapy procedures in pregnant patients pointing out the risks and benefits when the need for treatment.