Malignant neoplasms are one of the principal world health concerns and breast cancer is the most common type of cancer in women. Advances in cancer detection technologies allow treating it in early stages; however, it is necessary to develop treatments which carry fewer complications and aesthetic repercussions. This work presents a feasibility study for the use of microwave ablation as a novel technique for breast cancer treatment. A microwave applicator design is also being proposed for this purpose. The coupling of the designed antenna was predicted with computer simulation. The standing wave ratio obtained through simulation was 1.87 and the result of experimental validation was 1.04. The optimized antenna has an optimal coupling (SWR = 1.04) so ablation temperatures can be achieved in a relatively short time using low power. Varying the time and power, the heating pattern can be changed to treat different tumors. However, as some discrepancies are still present, a deeper study of the dielectric properties and their variation with temperature is required.

In the last decade, the analysis of shading or sunlight in architectural projects has become an important role in improving building thermal and lighting performances. Selecting an appropriate software tool for this type of analysis is a challenging task given the little information available. Therefore, the paper reviews the existing literature on heliodon designs and computational tools for building shadow analysis. The review includes a detailed description and classification of various types of heliodons, along with their operating principles and geometric features that affect their performance, including light sources, positioning mechanisms, and structures. This paper also includes descriptions and classification of the computational tools for testing building shadow patterns and applications in architecture. Moreover, this paper shows the capabilities of different software packages and their essential features, strengths, and limitations. In addition, we identified the current gaps in the literature on heliodons and computational tools. According to the results, for the case of heliodons, there is a lack of error analysis and a standardized calibration process, therefore, repeatability of the results is difficult to achieve. In the case of computational tools, they have reached a higher degree of success in the market than the heliodons, however, the cost of licensing and learning curve can be a limitation.

Introduction. Cancer is the second leading cause of death worldwide. Breast cancer is the second most common cause of cancer‐related mortality, accounting for 11.6% of the total number of deaths. The main treatments for this disease are surgical removal of the tumor, radiotherapy, and chemotherapy. Recently, different minimally invasive technologies have been applied (e.g., emission of electromagnetic waves, thermal and chemical means) to overcome the important side effects of these treatment modalities. The objective of this study was to develop and evaluate a predictive computational model of microwave ablation. Materials and Methods. The predictive computational model of microwave ablation was constructed by means of a dual‐slot coaxial antenna. The model was compared with an experiment performed using a breast phantom, which emulates the dielectric properties of breast tissue with segmental microcalcifications. The standing wave ratio (SWR) was obtained for both methods to make a comparison and determine the feasibility of applying electromagnetic ablation to premalignant lesions in breasts. Specifically, for the analysis of segmental microcalcifications, a breast phantom with segmental microcalcifications was developed and two computational models were performed under the same conditions (except for blood perfusion, which was excluded in one of the models). Results. The SWR was obtained by triplicate experiments in the phantom, and the measurements had a difference of 0.191 between the minimum and maximum SWR values, implying a change of power reflection of 0.8%. The average of the three measurements was compared with the simulation that did not consider blood perfusion. The comparison yielded a change of 0.104, representing a 0.2% change in power reflection. Discussion. Both experimentation in phantom and simulations demonstrated that ablation therapy can be performed using this antenna. However, an additional optimization procedure is warranted to increase the efficiency of the antenna.

Ingeniería Investigación y Tecnología es una publicación trimestral, arbitrada, de investigación científica y tecnológica editada e impresa por la Facultad de Ingeniería de la UNAM. Su propósito es difundir información y conocimientos originales e inéditos relacionados con la ingeniería. Es un espacio para profesores, investigadores, profesionales y estudiantes de todo el mundo.

En este estudio de caso se presenta el efecto que tienen los neuro-estimuladores eléctricos transcutáneos (tens, por sus siglas en inglés) en los síntomas motores causados por la enfermedad de Parkinson (ep). La ep se caracteriza por la baja producción de dopamina por parte de las neuronas que conforman al sistema nervioso central, que afecta principalmente a personas entre los 50 y 60 años de edad. En estudios previos se ha observado que, dependiendo del tratamiento farmacológico del paciente, la ep progresa en un promedio de 7.8±1.9 unidades en un promedio de 42 semanas en la calificación de la Escala Unificada de la Enfermedad de Parkinson (updrs, por sus siglas en inglés). Las electroterapias con tens han demostrado ser de gran utilidad en los síntomas motores de la ep, debido a que actúan tanto en músculos, ayudando con la rigidez y fortalecimiento de los mismos, como en nervios, con un efecto analgésico e inhibiendo las neuronas motoras. Se plantearon sesiones de terapia que incluyen electroterapia en las extremidades superiores y ejercicios físicos distintos, con la finalidad de disminuir la rigidez y temblor de extremidades, además, aumentar movilidad, fuerza y coordinación.

Introduction: Breast cancer is the leading cause of death among women worldwide, and treatments often have severe physiological and aesthetic side effects. Researchers are exploring minimally invasive techniques, such as Microwave Ablation therapy (MWA), to mitigate these effects. Methods: This study has investigated the impact of microwave ablation therapy on breast tissue with segmental microcalcifications, which can show breast cancer presence. This research work has used a coaxial dual-slot antenna model to apply microwave radiation and compare thermal and reflection parameters between homogeneous and heterogeneous breast tissues. Results: The results have shown homogeneous models to yield a power reflection below 17% and achieve the desired ablation temperature of 50°C in less than 250 seconds of therapy time. However, heterogeneous models have achieved a power reflection above 18% and achieved the desired ablation temperature in less than 250 seconds. This suggests that considering variation in dielectric properties within a homogeneous breast model can be more effective than considering tissue segmentation. Conclusion: Further research needs to optimize the antenna for each homogeneous breast density, considering other malignant tissues, which can potentially improve the effectiveness of microwave ablation therapy in treating breast cancer.