Estimation of organ and effective doses of CBCT scans of radiotherapy using size-specific field of view (FOV): a Monte Carlo study
This study aimed to investigate the influence of using fixed and patient-specific FOVs on the patient dose. Monte Carlo simulations were performed to simulate kV beams of the imaging system integrated into Truebeam linear accelerator using BEAMnrc code. Organ and size-specific effective doses resulting from chest and pelvis scanning protocols were estimated with DOSXYZnrc code using a phantom library developed by the National Cancer Institute (NCI) of the US. The library contains 193 (100 male and 93 female) mesh-type computational human adult phantoms, and it covers a large ratio of patient sizes with heights and weights ...
Source: Australasian Physical and Engineering Sciences in Medicine - March 27, 2024 Category: Biomedical Engineering Source Type: research

A novel textile-based UWB patch antenna for breast cancer imaging
In this study, a novel textile-based ultrawideband (UWB) microstrip patch antenna was designed and modeled to work in the 2 –11.6 GHz frequency range and a simulation was used to test its performance in early breast cancer detection. The antenna was designed with an overall size of 31*31 mm\(^2\) using a denim substrate and 100% metal polyamide-based fabric with copper, silver, and nickel to provide comfort for the wearer. The designed antenna was tested in four numerical breast models. The models ranged from simple tumor-free to complex models with small tumors. The size, structure, and position of the tumor were modifi...
Source: Australasian Physical and Engineering Sciences in Medicine - March 26, 2024 Category: Biomedical Engineering Source Type: research

Addressing challenges in diagnostic X-ray dosimetry: uncertainties and corrections for Al2O3:C-based optically stimulated luminescent dosimeters
This study aims to develop a method to determine ED and ESFs of Landauer nanoDot ™ OSLDs for clinical X-ray and investigate the uncertainties associated with ESF and ED correction factors. An area of 2 × 2 cm2 at the central axis of the X-ray field was used to establish the ESFs. A total of 80 OSLDs were categorized into “controlled” (n = 40) and “less-controlled” groups (n = 40). The ESFs of the OSLDs were determined using an 80 kVp X-ray beam quality in free-air geometry. The OSLDs were cross-calibrated with an ion chamber to establish the average calibration coefficient and ESFs. The OSLDs were ...
Source: Australasian Physical and Engineering Sciences in Medicine - March 25, 2024 Category: Biomedical Engineering Source Type: research

Machine learning-based analysis of 68Ga-PSMA-11 PET/CT images for estimation of prostate tumor grade
This study included 90 eligible participants out of 244 biopsy-proven prostate cancer patients who underwent staging68Ga-PSMA-11 PET/CT imaging. The patients were divided into high and low-intermediate groups based on their Gleason scores. The PET-only images were manually segmented, both lesion-based and whole prostate, by two experienced nuclear medicine physicians. Four feature selection algorithms and five classifiers were applied to Combat-harmonized and non-harmonized datasets. To evaluate the model's generalizability across different institutions, we performed leave-one-center-out cross-validation (LOOCV). The metri...
Source: Australasian Physical and Engineering Sciences in Medicine - March 25, 2024 Category: Biomedical Engineering Source Type: research

Semi-supervised learning towards automated segmentation of PET images with limited annotations: application to lymphoma patients
AbstractManual segmentation poses a time-consuming challenge for disease quantification, therapy evaluation, treatment planning, and outcome prediction. Convolutional neural networks (CNNs) hold promise in accurately identifying tumor locations and boundaries in PET scans. However, a major hurdle is the extensive amount of supervised and annotated data necessary for training. To overcome this limitation, this study explores semi-supervised approaches utilizing unlabeled data, specifically focusing on PET images of diffuse large B-cell lymphoma (DLBCL) and primary mediastinal large B-cell lymphoma (PMBCL) obtained from two ...
Source: Australasian Physical and Engineering Sciences in Medicine - March 21, 2024 Category: Biomedical Engineering Source Type: research

An effective cross-scenario remote heart rate estimation network based on global –local information and video transformer
AbstractRemote photoplethysmography (rPPG) technology is a non-contact physiological signal measurement method, characterized by non-invasiveness and ease of use. It has broad application potential in medical health, human factors engineering, and other fields. However, current rPPG technology is highly susceptible to variations in lighting conditions, head pose changes, and partial occlusions, posing significant challenges for its widespread application. In order to improve the accuracy of remote heart rate estimation and enhance model generalization, we propose PulseFormer, a dual-path network based on transformer. By in...
Source: Australasian Physical and Engineering Sciences in Medicine - March 19, 2024 Category: Biomedical Engineering Source Type: research

Effect of radioprotective curtain length on the scattered dose rate distribution and endoscopist eye lens dose with an over-couch fluoroscopy system
This study aimed to evaluate the scattered dose rate distribution and physician eye lens dose at different curtain lengths. Using an over-couch fluoroscopy system, dH*(10)/dt was measured using a survey meter 150  cm from the floor at 29 positions in the examination room when the curtain lengths were 0% (no curtain), 50%, 75%, and 100%. The absorbed dose rates in the air at the positions of endoscopist and assistant were calculated using a Monte Carlo simulation by varying the curtain length from 0 to 100%. The air kerma was measured by 10 min fluoroscopy using optically stimulated luminescence dosimeters at the eye surf...
Source: Australasian Physical and Engineering Sciences in Medicine - March 14, 2024 Category: Biomedical Engineering Source Type: research

A model for estimating peak skin dose in CT
AbstractIn interventional radiology patient care can be improved by accurately assessing peak skin dose (PSD) from procedures, as it is the main predictor for tissue-reactions such as erythema. Historically, high skin dose procedures performed in radiology departments were almost exclusively planar fluoroscopy. However, with the increase in use of technologies involving repeated or adjacent computed tomography (CT) such as CT fluoroscopy and multi-modality rooms, the peak skin dose delivered by CT needs to be considered. In this paper, a model to estimate the PSD delivered to a patient undergoing CT has been developed to a...
Source: Australasian Physical and Engineering Sciences in Medicine - March 7, 2024 Category: Biomedical Engineering Source Type: research

Development and validation of the effective CNR analysis method for evaluating the contrast resolution of CT images
AbstractContrast resolution is an important index for evaluating the signal detectability of computed tomographic (CT) images. Recently, various noise reduction algorithms, such as iterative reconstruction (IR) and deep learning reconstruction (DLR), have been proposed to reduce the image noise in CT images. However, these algorithms cause changes in the image noise texture and blurred image signals in CT images. Furthermore, the contrast-to-noise ratio (CNR) cannot be accurately evaluated in CT images reconstructed using noise reduction methods. Therefore, in this study, we devised a new method, namely, “effective CNR a...
Source: Australasian Physical and Engineering Sciences in Medicine - March 7, 2024 Category: Biomedical Engineering Source Type: research

Pattern classification of interstitial lung diseases from computed tomography images using a ResNet-based network with a split-transform-merge strategy and split attention
This study proposed a SE-ResNeXt-SA-18 for classifying pathological patterns of ILD. The SE-ResNeXt-SA-18 integrated the multipath design of the ResNeXt and the feature weighting of the squeeze-and-excitation network with split attention. The classification performance of the SE-ResNeXt-SA-18 was compared with the ResNet-18 and SE-ResNeXt-18. The influence of the input patch size on classification performance was also evaluated. Results show that the classification accuracy was increased with the increase of the patch size. With a 32  × 32 × 16 input, the SE-ResNeXt-SA-18 presented the highest performance with av...
Source: Australasian Physical and Engineering Sciences in Medicine - March 4, 2024 Category: Biomedical Engineering Source Type: research

Vectorgastrogram: dynamic trajectory and recurrence quantification analysis to assess slow wave vector movement in healthy subjects
AbstractFunctional gastric disorders entail chronic or recurrent symptoms, high prevalence and a significant financial burden. These disorders do not always involve structural abnormalities and since they cannot be diagnosed by routine procedures, electrogastrography (EGG) has been proposed as a diagnostic alternative. However, the method still has not been transferred to clinical practice due to the difficulty of identifying gastric activity because of the low-frequency interference caused by skin –electrode contact potential in obtaining spatiotemporal information by simple procedures. This work attempted to robustly i...
Source: Australasian Physical and Engineering Sciences in Medicine - March 4, 2024 Category: Biomedical Engineering Source Type: research

Navigating the 2021 ACPSEM ROMP workforce model: insights from a single institution
This study emphasises features inherent in the model, that need to be understood if the model is to be applied correctly. (Source: Australasian Physical and Engineering Sciences in Medicine)
Source: Australasian Physical and Engineering Sciences in Medicine - February 29, 2024 Category: Biomedical Engineering Source Type: research

Nanodosimetric quantity-weighted dose optimization for carbon-ion treatment planning
AbstractDose verification of treatment plans is an essential step in radiotherapy workflows. In this work, we propose a novel method of treatment planning based on nanodosimetric quantity-weighted dose (NQWD), which could realize biological representation using pure physical quantities for biological-oriented carbon ion-beam treatment plans and their direct verification. The relationship between nanodosimetric quantities and relative biological effectiveness (RBE) was studied with the linear least-squares method for carbon-ion radiation fields. Next, under the framework of the matRad treatment planning platform, NQWD was o...
Source: Australasian Physical and Engineering Sciences in Medicine - February 28, 2024 Category: Biomedical Engineering Source Type: research

Brain identification of IBS patients based on GBDT and multiple imaging techniques
AbstractThe brain biomarker of irritable bowel syndrome (IBS) patients is still lacking. The study aims to explore a new technology studying the brain alterations of IBS patients based on multi-source brain data. In the study, a decision-level fusion method based on gradient boosting decision tree (GBDT) was proposed. Next, 100 healthy subjects were used to validate the effectiveness of the method. Finally, the identification of brain alterations and the pain evaluation in IBS patients were carried out by the fusion method based on the resting-state fMRI and DWI for 46 patients and 46 controls selected randomly from 100 he...
Source: Australasian Physical and Engineering Sciences in Medicine - February 28, 2024 Category: Biomedical Engineering Source Type: research

Segmentation of liver and liver lesions using deep learning
AbstractSegmentation of organs and lesions could be employed for the express purpose of dosimetry in nuclear medicine, assisted image interpretations, and mass image processing studies. Deep leaning created liver and liver lesion segmentation on clinical 3D MRI data has not been fully addressed in previous experiments. To this end, the required data were collected from 128 patients, including their T1w and T2w MRI images, and ground truth labels of the liver and liver lesions were generated. The collection of 110 T1w-T2w MRI image sets was divided, with 94 designated for training and 16 for validation. Furthermore, 18 more...
Source: Australasian Physical and Engineering Sciences in Medicine - February 21, 2024 Category: Biomedical Engineering Source Type: research