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<jats:title>Abstract</jats:title> <jats:p>Optical penetration inside human skin is constrained by the wavelength dependent scattering and absorption losses by tissue microstructure and chromophores. This computational study investigates whether the signature of hematocrit variation from plexus i.e., the first skin layer having very small blood volume percentage distributed in capillary vessels, is retained by the detected photoacoustic response. The <jats:italic>in-silico</jats:italic> skin phantom is irradiated by a light source equivalent to a small footprint and low power (below 5 W) continuous wave LASER diode. As the low fluence can be compensated by exploiting strong absorption by targeted chromophores (hemoglobin molecules), an irradiation of wavelength 405 nm has been used to generate detectable pressure from capillary blood vessels of plexus. Optical energy deposition inside the tissue has been modelled using Monte Carlo technique and the pressure wave is computed using k-wave. It is found that with the increase in hematocrit from 10% to 50%, photoacoustic amplitude monotonically increases and gets almost doubled. The increment is about 30% in the range of hematocrit of physiological interest (from 30% to 50%). The variation follows a quadratic relationship for the entire hematocrit range. This photoacoustic signature of hematocrit variation has further been validated against minimum detectable pressure (800 Pa). This numerical model is expected to be an important basis to realize the idea of low cost small footprint <jats:italic>in-vivo</jats:italic> photoacoustic hematocrit measurement device.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Due to the increasing clinical application of alpha particles, accurate assessment of their dosimetry at the cellular scale should be strongly advocated. Although observations of the impact of cell and nuclear geometry have been previously reported, this effect has not been fully quantified. Additionally, alpha particle dosimetry presents several challenges and most conventional methodologies have poor resolution and are limited to average parameters across populations of cells. Meaningful dosimetry studies with alpha particles require detailed information on the geometry of the target at a subcellular scale. <jats:italic>Methods</jats:italic>. The impact of cellular geometry was evaluated for 3 different scenarios, a spherical cell with a concentric nucleus, a spherical cell with an eccentric nucleus and a model of a cell attached to a flask, consisting of a hemispherical oblate ellipsoid, all exposed to 1,700 <jats:sup>211</jats:sup>At radionuclide decays. We also evaluated the cross-irradiation of alpha particles as function of distance to a source cell. Finally, a nanodosimetric analysis of absorbed dose to the nucleus of a cell exposed to 1 Gy of different alpha emitting radionuclides was performed. <jats:italic>Results</jats:italic>. Simulated data shows the dosimetry of self-absorbed-dose strongly depends on activity localization in the source cell, but that activity localization within the source cell did not significantly affect the cross absorbed dose even when cells are in direct contact with each other. Additionally, nanodosimetric analysis failed to show any significant differences in the energy deposition profile between different alpha particle emitters. <jats:italic>Conclusions</jats:italic>. The collected data allows a better understanding of the dosimetry of alpha particles emitters at the sub-cellular scale. Dosimetric variations between different cellular configurations can generate complications and confounding factors for the translation of dosimetric outcomes into clinical settings, but effects of different radionuclides are generally similar.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>In this study, the novel poly (lactic-co-glycolic acid)-Hydroxyapatite nanoparticles (PLGA/HA) nanocomposite scaffolds were fabricated with solvent casting and particulate leaching (SCPL) method. The role of sodium chloride (NaCl) particles with diameters of 250-400 <jats:italic>μ</jats:italic>m as porogen agent in the mechanical strength of the produced scaffolds was evaluated. The prepared scaffolds were characterized using Fourier transform infrared (FT-IR), X‐ray diffraction (XRD), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA) and compressive tests. The results showed the high compressive strength and homogenous porous structures for PLGA/HA nanocomposite scaffolds compared to pure PLGA due to the presence of HA nanoparticles in nanocomposites. Furthermore, the compressive strength of nanocomposite scaffolds increased by varying the weight ratio of hydroxyapatite nanoparticles to polymer (0, 20, 40 wt%) at constant salt ratio and decreased by increasing the weight ratio of salt particles to polymer from 1 to 3 wt% due to more porosity in nanocomposite scaffolds. These results confirmed that not only the nanocomposite scaffolds exhibited high mechanical properties, homogenous structures, as well as good porosity but also, they could be useful for bone tissue application.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Developmental dysplasia of the hip (DDH) is a common orthopedic disease. A simple and cost-effective scientific tool for assisting the early diagnosis of DDH is urgently needed. This study proposed a new artificial intelligence (AI) model for automated measure of the CE angle to aid the diagnosis of DDH by modifying the Mask R-CNN algorithm.13228 anteroposterior pelvic x-ray images were collected from the PACS system of the second Hospital of Jilin University, of which 104 images were randomly selected as test data. The rest of x-ray images were labelled and preprocessed for model development. The new AI model was the constructed based modified Mask R-CNN model to detect key points for CE angle measurement. The performance of AI model on measuring CE angle was verified by comparing with three attending orthopaedic doctors. The mean CE angles on left and right pelvis measured by the AI model was 29.46 ± 6.98°and 27.92 ± 6.56°, respectively, while the mean CE angle measured by the three doctors was 29.85 ± 6.92°and 27.75 ± 6.45°, respectively. AI model displayed a higly consistency with the doctors in measuring CE angles. Besides, AI model showed a much high efficiency in term of measuring time-consumption. In this study, we successfully constructed a new effective model for measuring CE angle by identifying key points, which provided a new intelligent measurement tool for orthopedic image measurement and evaluation.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Recently, researchers have adapted Bioelectrical Impedance Analysis (BIA) as a new approach to objectively monitor wounds. They have indicated various BIA parameters associated to specific wound types can be linked to wound healing through trend analysis relative to time. However, these studies are conducted using wet electrodes which have been identified as possessing several shortcomings, such as unstable measurements. Thus, the adaption of e-textile electrodes has become an area of interest in measuring biosignals. E-textile electrodes are known to possess a significantly large polarization impedance (<jats:italic>Z</jats:italic> <jats:sub> <jats:italic>p</jats:italic> </jats:sub>) that potentially influences these biosignal measurements. In this study we aim to identify the suitability of e-textile electrodes to monitor wounds using BIA methodologies. By adapting suggested methodologies conducted in-vivo from previous studies, we used an ex-vivo model to observe the behaviour of e-textile electrodes relative to time. This was compared to common clinical wet electrodes, specifically Ag/AgCl. The objective of this study was to identify the BIA parameters that can be used to monitor wounds with e-textile electrodes. By analysing the BIA parameters relative to time, we observed the influence of <jats:italic>Z</jats:italic> <jats:sub> <jats:italic>p</jats:italic> </jats:sub> on these parameters.</jats:p>

<jats:title>Abstract</jats:title> <jats:p> <jats:italic>Purpose</jats:italic>. To compare the accuracies of the AAA and AcurosXB dose calculation algorithms and to predict the change in the down-stream and lateral dose deposition of high energy photons in the presence of material with densities higher that commonly found in the body. <jats:italic>Method</jats:italic>. Metal rods of titanium (d = 4.5 g cm<jats:sup>−3</jats:sup>), stainless steel (d = 8 g cm<jats:sup>−3</jats:sup>) and tungsten (d = 19.25 g cm<jats:sup>−3</jats:sup>) were positioned in a phantom. Film was position behind and laterally to the rods to measure the dose distribution for a 6 MV, 18 MV and 10 FFF photon beams. A DOSXYZnrc Monte Carlo simulation of the experimental setup was performed. The AAA and AcurosXB dose calculation algorithms were used to predict the dose distributions. The dose from film and DOSXYZnrc were compared with the dose predicted by AAA and AcurosXB. <jats:italic>Results</jats:italic>. AAA overestimated the dose behind the rods by 15%–25% and underestimated the dose laterally to the rods by 5%–15% depending on the range of materials and energies investigated. AcurosXB overestimated the dose behind the rods by 1%–18% and underestimated the dose laterally to the rods by up to 5% depending on the range of material and energies investigated. <jats:italic>Conclusion</jats:italic>. AAA cannot deliver clinically acceptable dose calculation results at a distance less than 10 mm from metals, for a single field treatment. Acuros XB is able to handle metals of low atomic numbers (Z ≤ 26), but not tungsten (Z = 74). This can be due to the restriction of the CT-density table in Eclipse<jats:sup>TM</jats:sup> TPS, which has an upper HU limit of 10501.</jats:p>

<jats:title>Abstract</jats:title> <jats:p> <jats:italic>Objective</jats:italic>. The mechanical properties of ribs from a large number of <jats:italic>post-mortem</jats:italic> human subjects (PMHS) were analyzed to search for variation according to age, sex or BMI in the sample. A large sample of specimens from different donors (<jats:italic>N</jats:italic> = 64) with a very wide range of ages and anthropometric characteristics was tested. <jats:italic>Methods</jats:italic>. Uniaxial tensile tests were used for a sample of coupons machined from cortical bone tissue in order to isolate the purely mechanical properties from the geometrically influenced properties of the rib. Each coupon is about 25 mm long and has a thickness of about 0.5 mm. The mechanical properties measured for each specimen/coupon include YM, yield stress, ultimate stress (maximum failure stress), ultimate strain, and resilience (energy to fracture of SED). The study provides new methodological improvements in DIC techniques. <jats:italic>Results</jats:italic>. This study is notable for using an atypically large sample of number of PMHS. The size of the sample allowed the authors to determine that age has a significant effect on failure stress (<jats:italic>p</jats:italic> &lt; 0.0001), yield stress (<jats:italic>p</jats:italic> = 0.0047), ultimate strain (<jats:italic>p</jats:italic> &lt; 0.0001) and resilience (<jats:italic>p</jats:italic> &lt; 0.0001) [numbers in parentheses represent the corresponding <jats:italic>p</jats:italic> − values]. Finally, there is a combined effect, so that for a given age, an increase of BMI leads to a decrease of the maximum strain (i.e. cortical bone is less stiff when both age and BMI are higher).</jats:p>

<jats:title>Abstract</jats:title> <jats:p>In this research work, a simple homemade cubic phantom was designed to validate the Image-Guided Radiotherapy (IGRT) set up and verified with the help of tungsten fiducial markers (size 2–3 mm) inserted into the cubic phantom. Phantom made up of Styrofoam, was scanned with the help of 16 slice Toshiba CT scanner where each slice was of 1 mm thickness and HU level set to −1000. A radio-opaque contrast medium was rubbed on the phantom to visualize the scanner images. Once the iso-center had been marked on a phantom with the help of in-room positioning laser and the fields (RT-LAT and AP) were applied on the contoured body of the phantom in Varian’s ARIA-11 Eclipse dosimeter software, the same position of the phantom was reproduced on Varian’s Linear Accelerator DHX. Known shifts of 3.0 to 30.0 mm from the marked iso-center were applied on the phantom by moving the couch in all six directions one by one. On each applied couch shift, an x-ray image of the phantom was acquired with the help of an MV portal imager of Linac in AP and RT-LAT direction. This image was superimposed with a reference image of phantom and shift accuracy calculated by ARIA-11 software was noted down. It turned out that irrespective of the position of the phantom on the couch, the calculated corrected shift and deviation from reference position was always between ± 1–2 mm which is the required accuracy for IGRT according to International Atomic Energy Agency (IAEA). This process was repeated 40 times and each time, the corrected shift came out to be ± 1–2 mm. We can conclude that our system is safe and accurate enough to perfectly position the actual patient for IGRT.</jats:p>

<jats:title>Abstract</jats:title> <jats:p> <jats:italic>Introduction</jats:italic>. The present study aims to investigate the dosimetric and radiobiological impact of patient setup errors (PSE) on the target and organs at risk (OAR) of the cervix carcinoma stage IIB patients treated with volumetric-modulated arc therapy (VMAT) delivery technique using plan uncertainty parameters module of Varian Eclipse treatment planning system and in-house developed DVH Analyzer program. <jats:italic>Materials and Methods</jats:italic>. A total of 976 VMAT plans were generated to simulate the PSE in the base plan that varies from −10 mm to 10 mm in a step size of 1 mm in x– (lateral), y– (craniocaudal), and z– (anteroposterior) directions. The different OAR and tumor (PTV) volumes were delineated in each case. Various plan quality metrics, such as conformity index (CI) and homogeneity index (HI), as well as radiobiological quantities, such as tumor control probability (TCP) and normal tissue control probability (NTCP), were calculated from the DVH bands generated from the cohort of treatment plans associated with each patient case, using an in-house developed ‘DVH Analyzer’ program. The extracted parameters were statistically analyzed and compared with the base plan’s dosimetric parameters having no PSE. <jats:italic>Results</jats:italic>. The maximum variation of (i) 2.4%, 21.5%, 0.8%, 2.5% in D<jats:sub>2cc</jats:sub> of bladder, rectum, small bowel and sigmoid colon respectively; (ii) 19.3% and 18.9% in D<jats:sub>max</jats:sub> of the left and right femoral heads (iii) 16.9% in D<jats:sub>95%</jats:sub> of PTV (iv) 12.1% in NTCP of sigmoid colon were observed with change of PSE in all directions. TCP was found to be considerably affected for PSEs larger than 4 mm in x<jats:sup>+</jats:sup>, y<jats:sup>+</jats:sup>, z<jats:sup>+</jats:sup> directions and 7 mm in x<jats:sup>-</jats:sup>, y<jats:sup>-</jats:sup> and z<jats:sup>-</jats:sup> directions, respectively. <jats:italic>Conclusion</jats:italic>. This study presents the effect of PSE on TCP and NTCP for the cervix carcinoma cases treated with VMAT technique and also recommends daily image guidance to mitigate the effects of PSE.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>One of the major concerns is the security and protection of individuals’ privacy in society. Biometric methods have been developed in recent years and they are widely used in many places and devices to protect information and assets. Wrist veins are inside the body and their pattern is unique for each person. In this paper, the PUT wrist vein dataset is used that comprises of palm and wrist vein images and each section has 1200 images of right and left hand. Wrist vein images are analyzed in the time-frequency domain by applying Fractional Fourier transform (FrFT), and the extracted features include phase, magnitude, real, and imaginary parts of FrFT coefficients. Since the number of features is very large by implementing FrFT, receiver operating characteristic (ROC) is applied for feature scoring and the best features are selected by this tool. Support Vector Machine (SVM) is used to classify real and impostor samples. The results of various features extracted by FrFT are compared, and according to the obtained results, we deduced that the phase feature is stronger than other features for person authentication based on wrist vein images, and this feature achieved 100% accuracy.</jats:p>