A radiation field is considered small if its dimension is lower than the range of secondary electrons and the collimating devices partially occlude the source. Different detector types, such as unshielded diodes, diamond detectors, and small-volume ion chambers, are used for small-field measurements. Although the active volumes of these detectors are small, their non-water equivalent materials cause

The use of proton therapy has the advantage of high dose concentration as it is possible to concentrate the dose on the tumor while suppressing damage to the surrounding normal organs. However, the range uncertainty significantly affects the actual dose distribution in the vicinity of the proton range, limiting the benefit of proton therapy for reducing the dose to normal organs. By measuring the annihilation

Prompt gamma detection during proton radiotherapy for range verification purposes will need to operate in both active and passive treatment beam environments. This paper describes prompt gamma measurements using a high resolution 2″ 2″ LaBr3 detector for a 200 MeV clinical passive-scatter proton beam. These measurements examine the most likely discrete prompt gamma rays emitted from tissue by detecting

Plastic scintillation dosimeters (PSDs) have many properties that make them desirable for relative dosimetry with MRI-LINACs. An in-house PSD, Farmer ionisation chamber and Gafchromic EBT3 film were used to measure central axis percentage depth dose distributions (PDDs) at the Australian MRI-LINAC Mean errors were calculated between each detector’s responses, where the in-house PSD was on average within

Objective: To determine the validity of the key mathematical assumptions used in electrical impedance tomography for human head tissues. Approach:Conductivity and permittivity data collected from available literature for each tissue within the human head have been evaluated and critiqued. The most relevant dielectric tissue data for each tissue was then used to assess the validity of the mathematical

Low-cost, portable electroencephalography (EEG) devices have become commercially available in the last 10 years. One such system, Emotiv’s EPOC, has been modified to allow event-related potential (ERP) research. Although the EPOC has been shown to provide data comparable to research-grade equipment and has been used in real-world settings, how EPOC performs without the electrical shielding, commonly

An efficient computational approach for optimal reconstructing parameters of binary-type physical properties for models in biomedical applications is developed and validated. The methodology includes gradient-based multiscale optimization with multilevel control space reduction by using principal component analysis (PCA) coupled with dynamical control space upscaling. The reduced dimensional controls

The purpose of this study was to estimate the biological impact of dosimetric perturbations of a fiducial marker and the daily number of fields in proton therapy for prostate cancer. Using a linear-quadratic model, normalized total doses (NTDs) of points where deposited dose was reduced from the prescribed dose by dosimetric perturbation of a fiducial marker were calculated in two hypothetical prostate

Current conventional 4D Cone Beam Computed Tomography (4DCBCT) imaging is hampered by inconsistent patient breathing that leads to long scan times, reduced image quality and high imaging dose. To address these limitations, Respiratory Motion Guided 4D cone beam computed tomography (RMG-4DCBCT) uses mathematical optimization to adapt the gantry rotation speed and projection acquisition rate in real-time

Color Vision Deficiency (CVD) is one of the most common types of vision deficiency. People with CVD have difficulty seeing color spectra depending on what types of retina photoreceptors are impaired. In this paper, the Ishihara test with 38 plates was used to examine the Electroencephalogram (EEG) of ten subjects with CVD plus ten healthy individuals. The recording was performed according to the 10–20

Introduction: The impact of dose heterogeneity within the tumor on TCP and NTCP was studied using various radiobiological models. The effect of the degree of heterogeneity index (HI) on TCP was also analyzed. Materials and Methods: Thirty-seven pre-treated liver SBRT cases were included in this study. Two different kinds of treatment techniques were employed. In both arms, the prescribed dose was received

Carbon-encapsulated magnetic nanoparticles are promising candidate materials for drug-delivery applications. However, due to their hydrophobic and aggregation properties, which indicate lower biocompatibility, proper surface modification of the carbon-based material is required. In the present study, we present the facile route to producing biocompatible magnetic nanocomposite iron oxide/carbon using

In this study we present endorectal digital prostate tomosynthesis (endoDPT), a proposed method of high resolution prostate imaging using an endorectal x-ray sensor and an external x-ray source. endoDPT may be useful for visualizing the fine detail of small structures such as low dose rate brachytherapy (LDRBT) seeds that are difficult to visualize with current methods. The resolution of endoDPT was

Endometrial cell culture is a method for investigating physiological or pathological conditions or simulating in vivo conditions for embryo culture. The natural function of the endometrium depends on a polarized epithelium and 3D stromal compartments. The polymer-based scaffolds of simple polyethersulfone (PES), laser scratched PES (PES-LS), and multiwall carbon nanotubes (MWCNT) composited PES (PES-MWCNT)

Intelligent analysis of present lifestyle may help to understand the development of the chronic diseases and the relationship of these diseases together. It is possible to reduce or prevent the development of these diseases. In this work, a novel intelligent method is introduced and applied for early detection of type 2 diabetic. Intelligent analysis depends mainly on evaluation life-threatening conditions

Capturing accurate representations of musculoskeletal system morphology is a core aspect of musculoskeletal modelling of the upper limb. Measurements of important geometric parameters such as the thickness of muscles and tendons are key descriptors of the underlying morphology. Though the measurement of those parameters can be estimated manually using cadaveric measurements, this is not an appropriate

Superparamagnetic iron oxide nanoparticles (SPIONs) are promising for clinical applications, because they have a characteristic nonlinear magnetic response when an external magnetic field is applied. This nonlinearity enables the distinct detection of SPIONs and makes measurements less sensitive to the human body and surgical steel instruments. In clinical applications, only a limited field strength

Objective: MR-linac machines are being developed for image-guided radiation therapy but the magnetic field of such machines could affect dose distributions. The purpose of this work was to evaluate the effect of a magnetic field on linac beam dosimetric parameters including penumbra for circular cones used in radiosurgery. Methods: Monte Carlo simulation was conducted for a linac machine with circular

Purpose Dose coefficients from rituximab, tetulomab, cetuximab, and huA33 monoclonal antibodies labelled with the radionuclide 177Lu were estimated for human organs and tumours via a theoretical simulation based on experimental results. Methods The real experimental results were obtained from radiopharmaceutical distribution in hairless mice. Using the Sparks and Aydogan method, the cumulated activity

In this study, the beam characteristics of a Euromechanics add-on MLC that has been installed on a Varian CLINAC 2100 C/D linear accelerator are presented. This was the first installation of 60-leaf PMLC from Euromechanics Company worldwide and all mechanical and dosimetric parameters were measured before clinical use of this kind of MLC. Mechanical tests were executed for different gantry and collimator

To accurately model dose in a magnetic field, the Lorentz force must be included in the traditional linear Boltzmann transport equation (LBTE). Both angular and spatial stabilization are required to deterministically solve this equation. In this work, a streamline upwind Petrov-Galerkin (SUPG) method is applied to achieve angular stabilization of the LBTE with magnetic fields. The spectral radius of

The aim of this work is the dosimetric characterization of a plane parallel ionization chamber under defined beam setups at the CERN Linear Electron Accelerator for Research (CLEAR). A laser driven electron beam with energy of 200 MeV at two different field sizes of approximately 3.5 mm FWHM and approximately 7 mm FWHM were used at different pulse structures. Thereby the dose-per-pulse range varied

We propose a semi-automatic segmentation pipeline designed for longitudinal studies considering structures with large anatomical variability, where expert interactions are required for relevant segmentations. Our pipeline builds on the regularized Fast Marching (rFM) segmentation approach by Risser et al (2018). It consists in transporting baseline multi-label FM seeds on follow-up images, selecting

This work uses a simple low-cost wearable device embedded with discrete thermal sensors to map the breast skin surface temperature. A methodology has been developed to estimate diameter, blood perfusion, metabolic heat generation and location in X, Y, Z coordinate of tumor from this discrete set of data. An interactive 3D thermal tomography was developed which provides a detailed 3D thermal view of

Bone is a dynamic biological tissue that acts as the primary rigid support of the body. Several systemic factors are responsible for pathologies that negatively affect its structural attributes. Although the bone is in continuous renewal by osteogenesis, metabolic diseases are the most common affectations that alter its natural equilibrium. Different techniques based on ionizing radiation are used

This study proposes that incorporating marker-based visibility constraints into the optimization of volumetric modulated arc therapy (VMAT) will generate treatment plans which not only ensure a higher chance of successfully applying real-time tumor tracking techniques, but also simultaneously satisfy dosimetric objectives. This was applied clinically and investigated for multiple disease sites (10

Purpose: Trajectory log files are increasingly being utilized clinically for machine and patient specific QA. The process of converting the DICOM-RT plan to a deliverable trajectory by the linac control software introduces some uncertainty that is inherently incorporated into measurement-based patient specific QA but is not necessarily included for trajectory log file-based methods. Roughly half of

Background: Spine injury risk due to military conflict is an ongoing concern among defense organizations throughout the world. A better understanding of spine biomechanics could assist in developing protection devices to reduce injuries caused by caudocephalad acceleration (+Gz) in under-body blasts (UBB). Although some finite element (FE) human models have demonstrated reasonable lumbar spine biofidelity

Small-angle x-ray scattering (SAXS) imaging may have the potential to image β-amyloid plaques in vivo in the brain without tracers for assessment of Alzheimer’s disease (AD). We use a laboratory SAXS system for planar imaging of AD model and control mouse brains slices to detect regions with high density of amyloid plaques. These regions were validated with histology methods. Using Monte Carlo techniques

Electron applicator cutouts for radiation therapy electron beam shaping are typically cast from Low Melting Point Alloys (LMPA), such as cerrobend. In this work, we describe the Monte Carlo modelling of novel 3D printed cutouts based on tungsten carbide powder and the resulting dose profiles subject to Elekta Agility electron beams. Cerrobend cutouts were also modelled using the Monte Carlo code EGSnrc

Electronic micro and nano-devices are suitable tools to monitor the activity of many individual neurons over mesoscale networks. However the inorganic materials currently used in microelectronics are barely accepted by neural cells and tissues, thus limiting both the sensor lifetime and efficiency. In particular, penetrating intracortical probes face high failure rate because of a wide immune response

Indirect dosimetry to calculate peak skin dose (PSD) is generally based on reference air kerma or kerma-area-product, with effects of table attenuation, inverse square law and backscatter factor applied. When the incident x-ray beam angle changes, these factors would change as well. The purpose of this study is to identify the impact of incident x-ray beam angle on the accuracy of indirect PSD calculation

Aim : The purpose of the current study was to compare between deep inspiration breath-hold (DIBH) and free-breathing (FB) method in the setup reproducibility and to perform a dosimetric comparison between both methods in left-sided breast cancer patients who undergo the UK FAST trial. Materials and methods : The online matching correction data were retrospectively collected for 50 patients treated

Mitral Valve Prolapse (MVP) is a common condition among people, which is often benign and does not need any serious treatment. However, this doesn’t mean that MVP can’t cause any problems. In malignant conditions, MVP can cause mitral failure and also heart failure. Early diagnosis of MVP is significantly important to control and reduce its complications. Since the phonocardiogram signal provides useful

Chemotherapy drugs are generally cytotoxic and can cause major side effects, including vomiting/nausea, fatigue, hair loss and pain. The use of targeted nanostructures to deliver drugs directly to tumours has the potential to reduce the side effects by decreasing the exposure of healthy cells and reducing the amount of drug needed. DNA can be used as a structural material to build drug-delivering nanorobots

Applying the concept of linear energy transfer (LET) to modelling of biological effects of charged particles usually involves calculation of the average LET. To calculate this, the energy distribution of particles is characterized by either the source spectrum or fluence spectrum. Also, the average can be frequency- or dose-weighted. This makes four methods of calculating the average LET, each producing

Proton beam treatment is being looked favourably now in breast treatment. Tissue expanders are often placed after mastectomy that contains metallic port for saline injection which produces dose perturbations in proton beam therapy with uncertain dosimetry. Dose perturbation for a stainless-steel injection port from a breast implant is investigated in this study. Measurements, Monte-Carlo simulation

With ever growing interest in far-reaching solutions for pervasive healthcare and medicine, polymer optical fibers have been rendered into textile forms. Having both fiber-optic functionalities and traditional fabric-like comfort, textile-integrated polymer optical fibers have been advocated to remove the technical barriers for long-term uninterrupted health monitoring and treatment. In this context

An innovative basic fibroblast growth factor (bFGF)-loaded polycaprolactone (PCL) fibrous membrane with highly aligned structure is developed for guided tissue regeneration (GTR). The aligned membrane is fabricated by electrospinning. In order to make efficient use of bFGF, PCL electrospun fibrous membrane is firstly surface-coated by self-polymerization of dopamine, and followed by immobilization

Hypertension is the condition where the normal blood pressure is high. This situation is manifested by the high pressure of the blood in the vein towards the vessel wall. Hypertension mostly affects the brain, kidneys, eyes, arteries and heart. Therefore, the diagnosis of this common disease is important. It may take days, weeks or even months for diagnosis. Often a device, called a blood pressure

Spinal fusion with pedicle-screw-rod is being used widely for treating spinal deformities diseases. Several biomechanical studies on screw rod based implant failure through screw pullout, bending, screw breakage have been performed. But few studies are available regarding the effect of strain for breakage of rod. So, the purpose of the present study is to observe strain at the rod connected with the

This paper presents a numerical model to investigate the deformation of biological cells by applying external electric fields operating at or near cell resonant frequencies. Cells are represented as pseudo solids with high viscosity suspended in liquid media. The electric field source is an atmospheric plasma jet developed inhouse, for which the emitted energy distribution has been measured. Viscoelastic

Chitosan (CS) and Platelet-Rich Plasma (PRP) both display interesting properties for wound healing applications. A hybrid CS-PRP biomaterial was previously developped, consisting of a freeze dried CS formulation solubilized in PRP that promotes tissue repair and regeneration. The purpose of the current study was to investigate the ability of the CS-PRP biomaterial to stimulate cell migration in vitro

This work investigates the suitability of locally fabricated 6 mol% Ge-doped optical fibres as dosimeters for small-field output ratio measurements. Two fabrications of fibre, cylindrical (CF) and flat (FF) fibres, were used to measure doses in small photon fields, from 4 to 15 mm. The findings were compared to those of commercial Ge-doped fibre (COMM), EBT3 film and an IBA CC01 ionization chamber

Silicon photomultipliers (SiPMs) are now widely used for positron emission tomography (PET) applications because of their high gain and low noise characteristics. The PET image quality has been improved with the advancement of time-of-flight (TOF) and depth-of-interaction (DOI) measurement techniques. For brain-dedicated PET systems, both TOF and DOI information are beneficial for enhancing the reconstructed

Organ-dedicated PET scanners are becoming more prevalent because of their advantages in higher sensitivity, improved image quality, and lower cost. Detectors utilized in these scanners have finer pixel size with depth of interaction (DOI) capability. This work presents a LYSO(Ce) detector module with DOI capability which has the potential to be scaled up to a high-resolution small animal or organ-dedicated

The purpose of this study is to develop a method for characterisation of time-of-flight (ToF) imaging system for application in deep inspiration breath-hold radiotherapy (DIBH-RT). The performance of an Argos 3D P330 ToF camera (Bluetechnix, Austria) was studied for patient surface monitoring during DIBH-RT using a phantom to simulate the intra-patient and inter-patient stability of the camera. Patient

An empirical model for small circular electron fields was developed. This can be of great help in the treatment planning process for small circular electron fields. A complete dosimetric analysis of the circular fields defined by electron cutouts diameters (2 cm–9 cm) was done for nominal electron energies ranging between 6 MeV and 20 MeV using a 3D water phantom and a pin-point ion chamber. Properties

We present a novel method for obtaining a 3D absorption map of a tissue-like turbid slab in the near-infrared spectral range by tomosynthesis. Transmittance data are obtained for a large number of oblique projection directions by scanning a cw laser source across the surface of the slab and by using a CCD camera for spatially resolved light detection. A perturbation model of light transport is used

Online monitoring of electroencephalogram (EEG) signals is challenging due to the high volume of data and power requirements. Compressed sensing (CS) may be employed to address these issues. Compressed sensing using a sparse binary matrix, owing to its low power features, and reconstruction/decompression using spatiotemporal sparse Bayesian learning have been shown to constitute a robust framework

Previous studies on computer aided detection/diagnosis (CAD) in 4D breast magnetic resonance imaging (MRI) usually regard lesion detection, segmentation and characterization as separate tasks, and typically require users to manually select 2D MRI slices or regions of interest as the input. In this work, we present a breast MRI CAD system that can handle 4D multimodal breast MRI data, and integrate

To preserve the fertility of young female cancer patients, ovarian tissue cryopreservation and transplantation have been investigated as next-generation reproductive medical technologies. Non-invasive visualization of follicles in ovarian tissue and cryopreservation of higher density tissue is essential for effective transplantation. We proposed the use of optical coherence tomography (OCT) that can

Under physiological conditions biomarker concentrations tend to rise and fall over time e.g. for inflammation. Ex vivo measurements provide a snapshot in time of biomarker concentrations, which is useful, but limited. Approaching real time monitoring of biomarker concentration(s) using a wearable, implantable or injectable in vivo sensor is therefore an appealing target. As an early step towards developing

This paper describes a novel strategy for the hemocompatibility improvement of poly(ethylene-co-vinyl alcohol) (EVAL) membranes by incorporation of a naturally occurring zwitterion, glycine. Crystalline glycine was directly integrated to the EVAL fibers via electrospinning. The membranes were characterized by Attenuated Total Reflection—Fourier Transform Infrared spectroscopy (ATR-FTIR), Scanning Electron

The human body contains approximately 20 billion blood vessels, which transport nutrients, oxygen, immune cells, and signals throughout the body. The brain's vasculature includes up to 9 billion of these vessels to support cognition, motor processes, and myriad other vital functions. To model blood flowing through a vasculature, a geometric description of the vessels is required. Previously reported

Vasculature is necessary to the healthy function of most tissues. In radiation therapy, injury of the vasculature can have both beneficial and detrimental effects, such as tumor starvation, cardiac fibrosis, and white-matter necrosis. These effects are caused by changes in blood flow due to the vascular injury. Previously, research has focused on simulating the radiation injury of vasculature in small

Background: Electrical impedance spectroscopy is a technique which evaluates differences in dielectric properties of tissues for cancer identification. Methods: Murine hepatic cancer model was developed by intraperitoneal administration of N-nitrosodiethylamine to male BALB/c mice. Tumors obtained were evaluated for their conductivity in frequency range of (4 Hz–5 MHz). All tumors were subjected to

Many diseases display heterogeneity in clinical features and their progression, indicative of the existence of disease subtypes. Extracting patterns of disease variable progression for subtypes has tremendous application in medicine, for example, in early prognosis and personalized medical therapy. This work presents a novel, data-driven, network-based Trajectory Clustering (TC) algorithm for identifying

The aim of this work is to develop and validate a computational model to investigate direct and indirect DNA damage by directly quantifying DNA strand breaks. A detailed geometrical target model was created in the Monte Carlo toolkit Geant4 to represent the nucleus of a single human cell with complete human genome. A calculation framework to simulate double-strand breaks (DSBs) was implemented using

Decellularization is a promising method for obtaining extracellular matrix scaffolds (ECM) to be used as replacement material in reconstructive procedures. The effectiveness of decellularization and the alterations to the ECM vary, depending on several factors, including the tissue source, composition and density. With an optimized decellularization process, decellularized scaffolds can preserve the