Background: On the elastic profiles of human teeth after radiotherapy for head and neck cancers, generation of dental complications, which may bring several side effects preventing the quality of life, has not well clarified. Thus, we aimed to show the applicability of using 320 MHz Scanning Acoustic Microscopy (SAM) in the evaluation of the tooth damage acoustically at the micrometer level following radiation therapy, and also in the determination of the safe dose limits to impede severe dental damage. Methods: This prospective study was performed by SAM employed at 320 MHz by an azimuthal resolution of 4.7 μm resolving enamel and dentin. A total of 45 sound human third molar teeth collected between September 2018 and May 2019 were used for the acoustic impedance measurements pre- and post irradiation. Nine samples for each group (control, 2 Gy, 8 Gy, 20 Gy, 30 Gy and 60 Gy) were evaluated to acquire the acoustic images and perform a qualitative analysis. Scanning Electron Microscopy (SEM) images were obtained to establish a relationship between micromechanical and morphological characteristics of the teeth. Statistical analysis was conducted using the Student t-test succeded by Mann-Whitney U investigation (p < .05), while SEM images were assessed qualitatively. Results: The analysis included 45 sound teeth collected from men and women 18 to 50 years old. Post irradiation micromechanical variations of human teeth were significant only in the radiation groups of 30 Gy and 60 Gy compared to pre-irradiation group for enamel (7.24 ± 0.18 MRayl and 6.49 ± 028 MRayl; p < 0.05, respectively). Besides, the teeth subjected to radiation doses of 20, 30 and 60 Gy represented significantly lower acoustic impedance values relative to non-irradiated group for dentin (6.52 ± 0.43 MRayl, 5.71 ± 0.66 MRayl and 4.82 ± 0.53 MRayl p < 0.05), respectively. Conclusions: These results are evidence for a safe acoustic examination device which may be a useful tool to visualize and follow the safe dose limits to impede severe dental damage through the radiation therapy treatment for head and neck cancers.

Skin cancer is a widespread and fatal disease in which early and accurate detection is an important aspect for effective treatment. The issues that arise when performing automated analysis of dermatoscopic images include artifacts such as hair, low contrast, and irregular edges of lesions that interfere with segmentation and classification. This study proposes an automated image preprocessing pipeline designed to remove artifacts while saving lesion texture and boundary. The method combines various computer vision methods and processes to produce a hairless dermatoscopic image of the sample, and lesion segmentation is subsequently performed using the HSV color space and binary masking. The effectiveness of the proposed preprocessing approach is evaluated using five state-of-the-art models: VGG16, ResNet50, InceptionV3, EfficientNet-B4, and DenseNet121.

Objective: To study the potential of in vivo quantitative ultrasound (QUS) imaging using Rényi Entropy (RE) and attenuation coefficient measurements for non-invasive characterization of skin tissue variations in breast cancer-related lymphedema (BCRL). Methods: Ultrasound radiofrequency (RF) signals recorded from the skin tissue of the arm in five women with Stage II BCRL and five healthy individuals as controls were analyzed. RE was computed from the RF data to quantify tissue heterogeneity, while the attenuation coefficient was estimated using the spectral-log difference method. Corresponding B-mode images were used for anatomical reference, and statistical comparisons were performed between two groups. Results: Both RE and attenuation coefficient values were significantly lower in lymphedematous dermis than in healthy skin (p<0.01), showing decreased signal complexity and changed acoustic scatterer characteristics associated with lymphatic fluid accumulation. Furthermore, the attenuation coefficients from healthy skin dermis fall into the same range as previously reported values, thus confirming the measurement approach. Spatially quantitative distributions were further demonstrated by parametric mapping of entropy and attenuation, enabling robust differentiation between control subjects and patients with BCRL. Conclusion: The findings of this study showed that the joint analysis of entropy and attenuation-based quantitative ultrasound metrics is sensitive to edema-related changes in the dermal microstructure of BCRL, detecting changes that are not readily discernible in conventional qualitative B-mode imaging. QUS-derived metrics provide complementary insight into tissue heterogeneity and acoustic energy loss at the microtissue level, whereas B-mode principally offers macroscopic anatomical information.

Objective: This study aimed to investigate microstructural changes in human dental hard tissues following single-fraction irradiation using high-resolution micro-computed tomography (micro-CT), with particular emphasis on potential differences between flattening filter (FF) and flattening filter-free (FFF) photon beam modalities. Methods: Sixteen extracted, non-carious human third molar teeth were included. All samples underwent baseline micro-CT imaging prior to irradiation. Teeth were then irradiated with 20 Gy in a single fraction using either 6 MV FF (600 cGy/MU) or 6 MV FFF (1400 cGy/MU) photon beams. Micro-CT images following irradiation were obtained with identical imaging conditions. Changes in bone volume (BV), total volume (TV), bone volume fraction (BV/TV), bone surface (BS), specific bone surface (BS/BV), bone mineral density (BMD), trabecular thickness (Tb.Th), and trabecular separation (Tb.Sp) were measured before and after irradiation. Results: Irradiation resulted in a substantial decrease in BV/TV and increases in BS and BS/BV (p < 0.05), suggesting micro-architectural remodeling and enhanced surface irregularity. No significant changes were detected in BV, TV, BMD, Tb.Th, or Tb.Sp. Comparison between FF and FFF beam modalities revealed no statistically significant differences in any micro-CT-derived parameter. Conclusion: Single-fraction 20 Gy irradiation induces early microstructural alterations in dental hard tissues characterized by changes in surface-related parameters rather than bulk mineral loss. Dose-rate differences between FF and FFF photon beams did not result in detectable micro-CT differences, supporting the clinical use of FFF beams at equivalent doses.