New article published in 12(4A) - ENAN / INAC 2024

Characterization of applicator material for treatment of superficial lesions in brachytherapy

Abstract: The treatment of superficial lesions by brachytherapy is performed using radioactive sources positioned inside tumors or at a short distance from them, to deposit the prescribed dose in the target volume. In the case of treating skin lesions, due to the proximity between the source and the patient's surface, it is important to use applicators that conduct the radiation source to the region to be treated, ensuring the safety and hygiene of the process. The treatment of keloids, for example, can be performed by brachytherapy. Considering that the applicators must undergo rigorous quality control, this study presents an evaluation of an applicator developed for the treatment of skin lesions, consisting of fifteen spheres of synthetic material, for use in High dose rate brachytherapy (HDR) equipment, model Nucletron Digital V3, equipped with an Ir-192 source. It was considered important to determine whether the spheres are suitable for medical use, direct contact with the patient's skin and sterilization methods. Furthermore, it was necessary to consider the material's resistance to the irradiation process, since the spheres must be used in multiple applications. In this sense, it was necessary to define the material of the spheres and, through this characterization, consider their suitability for the proposed use. Since the spheres were acquired with generic specifications, this study aimed to perform analyses to characterize the material, defining its composition. Consequently, the focus was to evaluate their safe use in the brachytherapy applicator. Read full article

High resolution X-ray microtomography as a tool for observation and classification of individual microplastics

Abstract: Plastics are synthetic polymers, widely used due to their durability, resistance, and lightweight properties. However, their extensive production and long-lasting nature have led to environmental challenges, notably the accumulation of plastic waste, where they degrade into microplastics (MPs)—particles smaller than 5 mm. These MPs contaminate various ecosystems, including water bodies, soils, and even the atmosphere. Understanding the complex structures of MPs is essential, but their heterogeneity makes characterization challenging. This study investigates the use of X-ray microtomography (microCT) as a tool for characterizing MPs. By scanning plastic fragments embedded in sediment, microCT provides detailed internal and external morphological data in a non-destructive manner. The total volume measured by microCT was approximately 150.00 mm³, accounting for 79% of the estimated theoretical volume, with a total surface area of 1061.00 mm². The analysis focused on morphometric parameters such as Feret diameter, anisotropy degree, and sphericity, which describe the shape and symmetry of individual particles. Results indicated significant variability in these parameters, reflecting the diverse nature of MPs. Additionally, microCT imaging detected slight variations in material composition, indicating potential heterogeneity within the polymers. The study highlights the need for standardization in MP classification and suggests that microCT, with its ability to detect subtle variations in material composition, holds promise for future environmental research. Further exploration of microCT's capabilities could enhance our understanding of MP behavior and impact, particularly in relation to their composition and environmental interactions. Read full article