Avaliação de segurança radiológica em procedimentos de pesquisa de linfonodo sentinela
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Data
Autores
Orientador
Koga, Katia Hiromoto 
Coorientador
Seraphim, Daniel Molena
Pós-graduação
Programa de Residência em Física Médica da Faculdade de Medicina - FMB
Curso de graduação
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Tipo
Trabalho de conclusão de residência
Direito de acesso
Acesso restrito
Resumo
Resumo (inglês)
Objective: To estimate the effective dose in Sentinel Lymph Node Mapping for professionals involved in the sentinel lymph node localization procedure and breast surgery for breast cancer patients. Methods: This prospective, cross-sectional study involved 55 patients undergoing Sentinel Lymph Node Mapping. Dose rate and exposure measurements were taken 0.3 meters from the injection site and from the sentinel lymph node. Based on these data, the activity and dose rates in the breast and lymph node at the start of surgery were estimated, and the effective dose for the professionals involved in surgery was determined. After excision of the lymph node, ex-vivo gamma probe measurements of the specimen were used to estimate its activity. The effective dose for the pathologist was then calculated based on handling time and distance from the specimen. Results: The average injected activity was 86.82 ± 36.52 MBq, with an average interval of 25.08 ± 2.63 hours from injection to the start of surgery. During the study period from December 2023 to August 2024, the effective dose at distances of 0.3 meters and 0.5 meters was 100.35 and 60.21 µSv, respectively. Therefore, the annual effective dose, in the most conservative scenario, at these distances of 0.3 meters and 0.5 meters was 311.21 and 112.03 µSv, respectively. The effective dose received by the pathologist during the study's measurement period was 3.71 µSv, and when extrapolated to a one-year period, the effective dose was 15.06 µSv. Conclusions: This study showed that the Sentinel Lymph Node Mapping conducted in our institution results in safe exposure levels for both the surgical team and the pathologist.
Resumo (inglês)
Breast cancer is one of the leading causes of death from neoplasia among women worldwide, with alarming estimates both globally and nationally. In Brazil, the National Cancer Institute (INCA) predicts more than 73,000 new cases between 2023 and 2025. This neoplasm can be influenced by genetic, environmental, and behavioral factors, and its main form of spread is through the lymphatic system, especially through the axillary chain. In this context, sentinel lymph node biopsy (SLNB) stands out as an effective diagnostic and therapeutic strategy, allowing the assessment of tumor spread with less morbidity compared to complete lymphadenectomy. The SLN procedure involves the administration of a radiopharmaceutical labeled with technetium-99m, which allows visualization and localization of the sentinel lymph node through lymphoscintigraphy and radioguided surgery. During the surgical procedure, a gamma probe is used to identify and remove the lymph node, which is then sent for pathological analysis. Although the use of radiopharmaceuticals is essential for the accuracy of the procedure, it involves exposure to ionizing radiation for the professionals involved. Thus, radiation protection practices are indispensable to ensure the safety of the team and must be aligned with recommendations from agencies such as the IAEA, ICRP, and CNEN. The institution's current protocol provides for an interval of approximately 24 hours between the administration of the radiopharmaceutical and surgery, which considerably reduces the activity present in the patient's body due to the physical half-life of technetium-99m. However, as different institutions adopt varying protocols regarding the injected activity and the time between injection and surgery, it is essential to measure the radiation doses received by the surgical team. This study aims to evaluate these exposures and verify whether the levels remain within the limits established for members of the public, ensuring compliance with the principles of radiation protection.
Descrição
Palavras-chave
Radioproteção, Câncer de mama, Linfonodo sentinela, Mapeamento do linfonodo sentinela
Idioma
Português
Citação
ZAMBUZI, Rafael Luiz Torres. Avaliação de segurança radiológica em procedimentos de pesquisa de linfonodo sentinela. Orientadora: Katia Hiromoto Koga. 2025. Trabalho de conclusão de curso ( Residência em Física médica) - Faculdade Medicina, Universidade Estadual Paulista (UNESP), Botucatu. 2025.
