Prostate-specific membrane antigen (PSMA) PET/CT imaging is widely used for quantitative image analysis, especially in radioligand therapy (RLT) for metastatic castration-resistant prostate cancer ...(mCRPC). Unknown features influencing PSMA biodistribution can be explored by analyzing segmented organs at risk (OAR) and lesions. Manual segmentation is time-consuming and labor-intensive, so automated segmentation methods are desirable. Training deep-learning segmentation models is challenging due to the scarcity of high-quality annotated images. Addressing this, we developed shifted windows UNEt TRansformers (Swin UNETR) for fully automated segmentation. Within a self-supervised framework, the model's encoder was pre-trained on unlabeled data. The entire model was fine-tuned, including its decoder, using labeled data.
In this work, 752 whole-body
GaGa-PSMA-11 PET/CT images were collected from two centers. For self-supervised model pre-training, 652 unlabeled images were employed. The remaining 100 images were manually labeled for supervised training. In the supervised training phase, 5-fold cross-validation was used with 64 images for model training and 16 for validation, from one center. For testing, 20 hold-out images, evenly distributed between two centers, were used. Image segmentation and quantification metrics were evaluated on the test set compared to the ground-truth segmentation conducted by a nuclear medicine physician.
The model generates high-quality OARs and lesion segmentation in lesion-positive cases, including mCRPC. The results show that self-supervised pre-training significantly improved the average dice similarity coefficient (DSC) for all classes by about 3%. Compared to nnU-Net, a well-established model in medical image segmentation, our approach outperformed with a 5% higher DSC. This improvement was attributed to our model's combined use of self-supervised pre-training and supervised fine-tuning, specifically when applied to PET/CT input. Our best model had the lowest DSC for lesions at 0.68 and the highest for liver at 0.95.
We developed a state-of-the-art neural network using self-supervised pre-training on whole-body
GaGa-PSMA-11 PET/CT images, followed by fine-tuning on a limited set of annotated images. The model generates high-quality OARs and lesion segmentation for PSMA image analysis. The generalizable model holds potential for various clinical applications, including enhanced RLT and patient-specific internal dosimetry.
To determine the effects of educational instructions on hemodialysis patients' knowledge and quality of life (QOL), we studied 99 patients randomly assigned to control and experimental groups after ...participation in a pretest exam. The two groups were not significantly different in terms of demographic composition. The instrument used in this study was a questionnaire regarding patients' knowledge and the standard questionnaire to assess QOL for end-stage renal disease (ESRD) patients. Then, intervention (nutritional education) was conducted in the experimental group lasting for 12 weeks. After 16 weeks, a post test regarding subjects' knowledge on dietary instructions and their QOL were as conducted. There was no significant difference in QOL score and knowledge score before and after intervention in the control group, but there was a significant difference in the experimental group. In addition, after the intervention, the difference in knowledge and QOL score persisted between the two groups. The results of this study supported the positive effects of educational program on patients' knowledge and QOL among ESRD patients. It is recommended that dietary instruction be included in all educational programs to improve ESRD patients' QOL.
Type 2 diabetes (T2D) is a chronic disease with a high prevalence globally, which is in the second place of importance for the investigation of chronic diseases. According to previous studies, ...Quality of Life (QOL) is low in diabetic patients. Hence, this study was conducted with the aim to evaluate the effect of the empowerment model on the QOL of patients with T2D.
A randomized controlled trial was performed on 103 T2D patients over 18 years of age, with a definitive diagnosis of diabetes and medical records in a diabetic center. Patients were randomly assigned to either the intervention or the control groups. Routine education was presented to the control group, and the empowerment model was used for education in the experimental group for 8 weeks. The data collection tools used consisted of a demographic characteristics form and the diabetic clients QOL questionnaire. The one-way analysis of variance, Chi-square test, paired
-test, and independent
-test were used for data analysis.
After the intervention, there were significant differences between the two groups in terms of the physical (
= 0.003), mental (
= 0.002), social (
= 0.013), economic (
= 0.042), and illness and treatment dimensions of QOL (
= 0.033), as well as the total QOL score (
= 0.011).
According to the results of this study, the training program based on empowerment significantly increased the QOL of patients with T2D. Therefore, using this method can be recommended in patients with T2D.
Radiotheranostics refers to the pairing of radioactive imaging biomarkers with radioactive therapeutic compounds that deliver ionizing radiation. Given the introduction of very promising ...radiopharmaceuticals, the radiotheranostics approach is creating a novel paradigm in personalized, targeted radionuclide therapies (TRTs), also known as radiopharmaceuticals (RPTs). Radiotherapeutic pairs targeting somatostatin receptors (SSTR) and prostate-specific membrane antigens (PSMA) are increasingly being used to diagnose and treat patients with metastatic neuroendocrine tumors (NETs) and prostate cancer. In parallel, radiomics and artificial intelligence (AI), as important areas in quantitative image analysis, are paving the way for significantly enhanced workflows in diagnostic and theranostic fields, from data and image processing to clinical decision support, improving patient selection, personalized treatment strategies, response prediction, and prognostication. Furthermore, AI has the potential for tremendous effectiveness in patient dosimetry which copes with complex and time-consuming tasks in the RPT workflow. The present work provides a comprehensive overview of radiomics and AI application in radiotheranostics, focusing on pairs of SSTR- or PSMA-targeting radioligands, describing the fundamental concepts and specific imaging/treatment features. Our review includes ligands radiolabeled by
Ga, 18F,
Lu,
Cu,
Y, and 225Ac. Specifically, contributions via radiomics and AI towards improved image acquisition, reconstruction, treatment response, segmentation, restaging, lesion classification, dose prediction, and estimation as well as ongoing developments and future directions are discussed.
Background and Objectives: Emergency medical technicians (EMTs), as the front line of dealing with patients with COVID-19, are exposed to the intensification of stress caused by these conditions, and ...it is essential to identify related factors, such as resilience and spiritual intelligence in this context. This study was conducted to determine the relationship between perceived stress, spiritual intelligence, and resilience of EMTs during the COVID-19 pandemic. Methods: This cross-sectional study was conducted on 108 EMTs in Shahroud in 2021. Data collection tools included the demographic checklist, Cohen’s perceived stress questionnaire, King’s spiritual intelligence questionnaire, and Conrad Davidson’s questionnaire (CD-RISC). To analyze the data, descriptive and inferential (independent t-test, Pearson correlation, and multiple regression) statistics were used. Results: The mean scores of perceived stress and resilience of employees were at medium and high levels, respectively. There was no significant relationship between perceived stress and spiritual intelligence (r=-0.49, P=0.24), but there was a meaningful negative correlation between perceived stress and resilience (r=-0.31, P=0.002). A positive and significant relationship was observed between perceived stress score and age and work experience. Conclusion: Considering the significant relationship between perceived stress and resilience in the present study, it is suggested that the administrators provide solutions such as creating training courses to manage stress and increase resilience in EMTs.
Background: This study evaluated the performances of neural networks in terms of denoizing metal artifacts in computed tomography (CT) images to improve diagnosis based on the CT images of patients. ...Methods: First, head-and-neck phantoms were simulated (with and without dental implants), and CT images of the phantoms were captured. Six types of neural networks were evaluated for their abilities to reduce the number of metal artifacts. In addition, 40 CT patients' images with head-and-neck cancer (with and without teeth artifacts) were captured, and mouth slides were segmented. Finally, simulated noisy and noise-free patient images were generated to provide more input numbers (for training and validating the generative adversarial neural network GAN). Results: Results showed that the proposed GAN network was successful in denoizing artifacts caused by dental implants, whereas more than 84% improvement was achieved for images with two dental implants after metal artifact reduction (MAR) in patient images. Conclusion: The quality of images was affected by the positions and numbers of dental implants. The image quality metrics of all GANs were improved following MAR comparison with other networks.
Background
Materials with high atomic numbers are part of the composition of dental implant systems. In radiotherapy of oral cavity cancers, an implant can cause dose perturbations that affect target ...definition, dose calculation, and dose distribution. In consequence, this may result in poor tumor control and higher complications. In this study, we evaluated dose homogeneity when a dental implant replaced a normal tooth. We also aimed to evaluate the concordance of dose calculations with dose measurements.
Materials and methods
In this study, 2 sets of planning CT scans of a phantom with a normal tooth and the same phantom with the tooth replaced by a Z1 TBR dental implant system were used. The implant system was composed of a porcelain-fused-to-metal crown and titanium with a zirconium collar. Three radiotherapy plans were designed when the density of the implant material was corrected to match their elements, or when all were set to the density of water, or when using the default density conversion. Gafchromic EBT-3 films at the level of isocenter and crowns were used for measurements.
Results
At the level of crowns, upstream and downstream dose calculations were reduced when metal kernels were applied (M-plan). Moreover, relatively measured dose distribution patterns were most similar to M-plan. At this level, relative to the non-implanted phantom, mean doses values were higher with the implant (215.93 vs. 192.25), also, new high-dose areas appeared around a low-dose streak forward to the implant (119% vs. 95%).
Conclusions
Implants can cause a high dose to the oral cavity in radiotherapy because of extra scattered radiation. Knowledge of the implant dimensions and defining their material enhances the accuracy of calculations.
Electrostatic Micro-Hydraulic Systems Sadeghi, Mahdi M.; Kim, Hanseup S.; Peterson, Rebecca L. Becky ...
Journal of microelectromechanical systems,
2016-June, 2016-6-00, 20160601, Volume:
25, Issue:
3
Journal Article
Peer reviewed
MEMS micro-hydraulic structures for amplification of force or deflection are introduced. These structures are integrated with capacitances to form electrostatic micro-hydraulic actuators (EMA). ...Hydraulic amplification and liquid permittivity are used to create stand-alone, efficient, and large deflection, and high force actuators. Force is generated using electrostatics with no need for external pressure sources. Use of integrated electrostatic force significantly reduces the device size. Utilizing this concept, a micro-valve and two types of EMA micro-piston arrays (water-based and silicone oil-based) are fabricated and tested. The micro-valve can switch fluid flows with the pressure ranging from 10 to 50 kPa at a maximum flow conductance of 20.3 sccm at 10 kPa with an actuation voltage of 340 V DC or 120 V AC . The silicone oil based micro-hydraulic micro-piston array has shown a maximum out-of-plane deflection of about 100 μm at 210 V DC , and a maximum bandwidth of about 5 Hz with a foot print size of 0.16 cm 2 and a maximum power consumption of 20 μW at 1 Hz. These devices are the smallest ever reported microhydraulic systems that include the actuation source.
64Cu is a favorable radionuclide in nuclear medicine applications because of its unique characteristics such as three types of decay (electron capture, β− and β+) and 12.7 h half-life. Production of ...64Cu by irradiation natCu and natCuNPs in Tehran Research Reactor was investigated. The characteristics of copper nanoparticles were investigated with SEM, TEM and XRD analysis. The cross section of 63Cu(n,γ)64Cu reaction was done with TALYS-1.8 code. The activity value of 64Cu was calculated with theoretical approach and MCNPX-2.6 code. The results were compared with related experimental results which showed good adaptations between them. Keywords: 64Cu radioisotope, Copper nanoparticles, Production yield, MCNPX, TALYS-1.8
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