Systematic Setup Research Articles

Revolutionizing Battery Longevity by Optimising Magnesium Alloy Anodes Performance

This research explores the enhancement of electrochemical performance in magnesium batteries by optimising magnesium alloy anodes, explicitly focusing on Mg-Al and Mg-Ag alloys. The study’s objective was to determine the impact of alloy composition on anode voltage stability and overall battery efficiency, particularly under extended cycling conditions. The research assessed the anodes’ voltage behaviour and internal resistance across magnesium bis(trifluoromethanesulfonyl)imide (Mg(TFSI)2) electrolyte formulations using a systematic setup involving cyclic voltammetry on the anode and electrochemical impedance spectroscopy. The Mg-Al alloy demonstrated superior performance, with minimal voltage drop and lower resistance increase than the Mg-Ag alloy. The results showed that the Mg-Al alloy maintained over 85% energy efficiency after 100 cycles, significantly outperforming the Mg-Ag alloy, which exhibited increased degradation and efficiency reduction to approximately 80%. These findings confirm that incorporating aluminium into magnesium anodes stabilises the anode voltage and enhances the overall battery efficiency by mitigating degradation mechanisms. Consequently, the Mg-Al alloy is identified as an up-and-coming candidate for use in advanced battery technologies, offering energy density and cycle life improvements. This study lays the groundwork for future research to refine magnesium alloy compositions further to boost battery performance.

Stage by stage E- Ecommerce market database analysis by using machine learning models

In the recent era, advertising strategies are far more sophisticated than those of their predecessors. In marketing, business contacts are essential for online transactions. For that, communication needs to develop a database; this database marketing is also one of the best techniques to enhance the business and analyze the market strategies. Businesses may improve consumer experiences, streamline supply chains, and generate more income by analyzing E-Commerce market datasets using machine learning models. In the ever-changing and fiercely competitive world of e-commerce, the multi-stage strategy guarantees a thorough and efficient use of machine learning. Analyzing the database can help to understand the user's or industry's current requirements. Machine Learning models are developed to support the marketing sector. This machine learning model can efficiently operate or analyze e-commerce in different stages, i.e., systematic setup, status analysis, and model development with the implementation process. Using these models, it is possible to analyze the marketing database and create new marketing strategies for distributing marketing objects, the percentage of marketing channels, and the composition of marketing approaches based on the analysis of the marketing database. It underpins marketing theory, data collection, processing, and positive and negative control samples. It is suggested that e-commerce primarily adopt the database marketing method of the model prediction. This is done by substituting the predicted sample into the model for testing. The issue of unequal marketing item distribution may be resolved by machine learning algorithms on the one hand, and prospective customer loss can be efficiently avoided on the other. Also, a proposal for an application approach that enhances the effectiveness of existing database marketing techniques and supports model prediction is made.

Unmasking anxiety: a head-to-head comparison of open and closed masks in head and neck cancer radiotherapy.

Facemasks accurately immobilise patients with head and neck cancer (HNC) receiving radiotherapy (RT). However, such masks are associated with treatment related distress, a prognostic factor for poorer survival. Open masks offer increased comfort and patient satisfaction. We investigated whether open masks could immobilise patients without affecting treatment accuracy. Over an 18-month period, all HNC RT patients with anxiety were offered open masks. Once 30 patients had completed treatment, set-up data was compared to patients in closed masks. The mean displacement and one-dimensional standard deviations (SD) of the mean, systematic and random set-up errors were calculated for translational directions: anterior-posterior (x), superior-inferior (y), medial-lateral (z). The mean and SD of the mean was calculated for rotational displacements. Mann-Whitney U was used to determine any significant differences between set-up data. Sixty patients were included (30 open & 30 closed masks). There was no statistically significant difference found in the x (p = 0.701), y (p = 0.246) or z (p = 0.535) direction for the SD of the mean displacements between both masks. No statistically significant difference was found in the SD of means for rotational displacements. The calculated planning target volume (PTV) margin requirements were minimally less for the closed masks 3.5, 2.6, and 2.7 mm (x, y, z, respectively) versus 4.2, 3.2, and 3.7 mm, respectively, for open masks. Our study demonstrates that open masks maintain accuracy at levels comparable to closed masks in patients with anxiety. The minor difference in the calculated PTV margin could be rectified with daily on-line imaging or surface guided imaging.

Developing a Model Proposal to Evaluate the Authenticity of Traditional Housing; Malatya Case Study

Anatolia has been used as a settlement area by many civilizations throughout history due to its geopolitical and geographical features. Traditional houses in Anatolia convey the thousands of years of culture and identity of the region where they are located, with their unique architectural style. In this respect, traditional houses appear as the most important cultural heritage values that convey information such as the social, cultural, economic and architectural style of the period. Historical textures have been in change and transformation in the Malatya region, as in every region of Anatolia. However, Malatya has largely lost its traditional houses and texture due to many reasons such as rapid urbanization, unconsciousness, rent, and the destructive effect of time. In this study, which was prepared by addressing this problem, Fuzzy Logic and AHP (Analytical Hierarchy Process) analysis system was used in order to evaluate the authenticity of civil architectural examples located in traditional tissue pieces in the urban area of Malatya and to protect these structures. Thus, it is aimed to develop an authenticity assessment method together with the experts of the subject (conservation experts, architectural historians, art historians). It is aimed to determine the authenticity of the buildings numerically and proportionally with the authenticity evaluation model developed with a systematic setup. Ahmet Kökçü House, located in Yakınca Neighborhood, was chosen as the study area due to reasons such as the fact that it largely preserved its traditional texture as a field study and faced extinction as a result of the rapid urbanization of Malatya's central city wall reaching the border of Yeşilyurt district. With the authenticity assessment model developed in this context, the authenticity of the building was determined by experts and suggestions were made for the preservation of the building.

Two-dimensional and Three-dimensional Image-guided Evaluation of Patient Positioning for Intensity-modulated Radiation Therapy of Head and Neck Cancer

Patient positioning accuracy is critical in radiation therapy, especially in intensity-modulated radiation therapy (IMRT) for head and neck cancer (HNC), as it can affect treatment effectiveness and safety. This retrospective study aimed to evaluate the accuracy of patient positioning techniques and compare the effectiveness of using multiple image-guided (IG) methods for IG-IMRT of HNC. Cone-beam computed tomography (CBCT) and kV-planar imaging (OBI) collected 3240 treatment couch coordinates in three translational directions from 60 HNC patients undergoing IMRT. Inter-fraction errors were assessed by registering the scans to the planning CT, and the population systematic set-up error (Σ), random error (σ), and planning target volume (PTV) margin were calculated. The results between OBI and CBCT were analyzed and compared using one-way ANOVA. The findings demonstrated that more than 80% of the image-guided patient positioning set-ups were acceptable. The mean couch displacement for image-guided techniques was negligible in all translational directions using OBI and CBCT. However, the PTV margin for both methods was more than 0.5 cm, except for the CBCTA-P direction. This study highlights the effectiveness of OBI and CBCT as modalities for evaluating and improving the accuracy of IMRT in HNC patients. Determination of the systematic and random errors and calculating the optimal PTV margin without rematching images can help improve the precision of patient positioning and ultimately lead to better treatment outcomes.

CBCT Guided Interfraction Absolute Displacement and Setup Error Assessment during Breast Prone Radiotherapy

To calculate interfraction absolute displacement/shift and setup error using cone beam computed tomography (CBCT) during breast prone radiotherapy. Fifty-nine patients undergoing prone whole breast-irradiation after breast-conserving surgery (BCS) were studied as part of an institutional review board- approved prospective trial. Setup precision was monitored using a daily online CBCT. Translational shifts in 3 axes (AP: anterior posterior; LR: left right; and SI: superior inferior) and 3 rotations (pitch, roll, and rtn) after CBCT were analyzed for 1062 treatment fractions. The random and systematic setup errors (SE) were calculated and were analyzed for time trends during the course of radiotherapy. For absolute inter-fractional shifts, the numbers of fractions exceeding 10 mm in the AP, LR, and SI directions were 6.5%, 17.42% and 8.92%, respectively; 0%, 0% and 1.31% fractions exceeded 3°for pitch, roll, and Rtn, respectively. The population systematic errors were 1.89/2.91/1.98 mm in AP/SI/LR directions, while the random error were 2.72/3.99/3.31 mm. In pitch, roll, rtn rotations, the population systematic error were 0.64°/0.49°/0.46°, and 0.89°/0.90°/0.93° for the random error. Without correction these would correspond to a clinical to planning target volume margin of 6.64/10.08/7.26 mm in AP/SI/LR directions and 2.22°/1.79°/1.8° in pitch, roll, rtn rotations. The magnitude of inter-fraction motion was not correlated with patient treatment time accept in AP direction (P = 0.000). SE was larger in prone position in breast cancer patients, attributable mostly to random errors, which emphasize the need for on-line imaging guidance in breast prone radiotherapy. 10mm margins would adequately cover the target volume and account for setup errors in the absence of IGRT.

Comparison of setup accuracy of optical surface image versus orthogonal x-ray images for VMAT of the left breast using deep-inspiration breath-hold.

To compare the setup accuracy of optical surface image (OSI) versus orthogonal x-ray images (2DkV) using cone beam computed tomography (CBCT) as ground truth for radiotherapy of left breast cancer in deep-inspiration breath-hold (DIBH). Ten left breast DIBH patients treated with volumetric modulated arc therapy (VMAT) were studied retrospectively. OSI, 2DkV, and CBCT were acquired weekly at treatment setup. OSI, 2DkV, and CBCT were registered to planning CT or planning DRR based on a breast surface region of interest (ROI), bony anatomy (chestwall and sternum), and both bony anatomy and breast surface, respectively. These registrations provided couch shifts for each imaging system. The setup errors, or the difference in couch shifts between OSI and CBCT were compared to those between 2DkV and CBCT. A second OSI was acquired during last beam delivery to evaluate intrafraction motion. The median absolute setup errors were (0.21, 0.27, 0.23cm, 0.6°, 1.3°, 1.0°) for OSI, and (0.26, 0.24, 0.18cm, 0.9°, 1.0°, 0.6°) for 2DkV in vertical, longitudinal and lateral translations, and in rotation, roll and pitch, respectively. None of the setup errors was significantly different between OSI and 2DkV. For both systems, the systematic and random setup errors were ≤0.6cm and ≤1.5° in all directions. Nevertheless, larger setup errors were observed in some sessions in both systems. There was no correlation between OSI and CBCT whereas there was modest correlation between 2DkV and CBCT. The intrafraction motion in DIBH detected by OSI was small with median absolute translations <0.2cm, and rotations ≤0.4°. Though OSI showed comparable and small setup errors as 2DkV, it showed no correlation with CBCT. We concluded that to achieve accurate setup for both bony anatomy and breast surface, daily 2DkV can't be omitted following OSI for left breast patients treated with DIBH VMAT.

Comparison of cone beam computed tomography (CBCT)-based image guided radiotherapy approaches in the reduction of setup uncertainties during deep inspiration breath-hold radiotherapy (DIBH-RT) for left breast cancer

Advances in radiotherapy has allowed higher cure rates for cancer such as breast and thus, it is important to reduce the possible radiation side effects from exposure to other organs such as the heart. Deep inspiration breath-hold radiotherapy technique (DIBH-RT) significantly reduces cardiac dose during left breast radiotherapy, but the patient setup requires careful adoption of image guidance radiotherapy technique (IGRT) approaches. This study investigates the effectiveness of cone beam computed tomography (CBCT)-based IGRT protocols for patients' inter-fraction set-up correction. Setup error data from two patients’ groups; A and B who had daily CBCT and first 3 fractions + weekly CBCT imaging respectively, were analysed. This constitutes a total of 13 left breast cancer patients treated using DIBH-RT at Advanced Medical Dental Institute (AMDI), Universiti Sains Malaysia (USM), Malaysia. The analysis was performed using MATLAB (MathWorks Inc Natick MA) to calculate the mean setup errors. The population systematic (∑) and random (σ) errors were calculated for non-IGRT, online, and two offline IGRT protocols; no action level (NAL) and extended no action level (eNAL) for each patient group. The corresponding planning target volume (PTV) margin and its percentage reduction for each of the IGRT protocols were established using van Herk margin recipe. The least population systematic setup error and PTV margin were found when using the online protocol (∑X/Y/Z = 0.17/0.22/0.31 mm; PTVX/Y/Z = 0.71/0.92/1.28 mm) followed by eNAL (∑X/Y/Z = 1.32/1.94/1.85 mm; PTVX/Y/Z = 5.75/7.99/8.46 mm), NAL (∑X/Y/Z = 1.45/2.26/1.84 mm; PTVX/Y/Z = 6.27/8.93/8.46 mm) and non-IGRT (∑X/Y/Z = 2.28/3.35/3.10 mm; PTVX/Y/Z = 7.77/10.85/10.93 mm). Up to 90% in PTV margin reduction is achieved with the online protocol. In conclusion, the use of IGRT during DIBH-RT for left breast cancer patients reduces patient set-up error and allows the use of tighter PTV margins. The online IGRT protocol was shown to be more effective in the reduction of errors and the PTV margin followed by eNAL and NAL offline IGRT protocols.

The Effect of Microchannel Cavity on the Bulk Acoustic Wave-Induced Acoustofluidics: Numerical Investigation

Acoustofluidics is emerging as an effective approach to manipulating microparticles and cells no matter their optical, electrical, and magnetic properties and no requirement of pre-processing. Standing field in a microfluidic channel produced by a bulk acoustic wave (BAW) could accumulate the microparticles at the plane of the pressure node. In order to further accumulate them from a plane (2D) to a line (1D), a new strategy without significant change of the systematic setup (i.e., adding another orthogonal standing field) was proposed and evaluated numerically in a full-sized model. Concave cavity on the conventional rectangular microchannel leads to a slight increase of the maximum acoustic pressure and distortion of the wavefront, but two more vortexes close to the edge of the bottom cavity and directional acoustic radiation forces in the middle line of the microchannel (the upper part pointing downwards while the lower part upwards). Subsequently, most of the microparticles are accumulated in a very small region in the middle line of the microchannel. The effect of the cavity geometry on such a novel phenomenon was investigated. With the increase of the diameter of the cavity from 170 μm to 260 μm, the resonant frequency of the microchannel, the maximum acoustic pressure, and the maximum acoustic streaming velocity increased by 13%, 78%, and 7.1 fold, respectively. When shifting the center of the cavity, the position of 1D accumulated microparticles could be changed correspondingly. In summary, the characteristics of acoustofluidics are highly dependent on the microchannel geometry. Microparticle accumulation with a significant reduction to one dimension using only one acoustic standing field is theoretically possible by introducing an appropriate concave cavity in the conventional rectangular microchannel.

Changing the Face of Head and Neck Radiotherapy

<h3>Purpose/Objective(s)</h3> Radiotherapy plays a key role in the of the management of head and neck cancer patients with approximately 80% of patients receiving RT at least once during their cancer journey. Immobilization of patients during radiotherapy treatment, is essential to ensure treatment accuracy, and requires the use of a facemask. However, masks are associated with significant treatment related distress and a phenomenon called "mask anxiety". Many patients have difficulty swallowing and breathing which makes a closed facemask even less tolerable. In order to improve patients' radiotherapy treatment experience, we piloted a "faceless" open mask in our department to investigate whether such masks could be used, to reduce patients' distress without impacting on treatment accuracy, by comparing set up data for full versus open masks. <h3>Materials/Methods</h3> Over an 18-month period, all head and neck cancer patients undergoing radical radiotherapy, with a history of anxiety or claustrophobia, were offered open masks. Once 30 patients had completed radiotherapy treatment with the open mask, we analyzed the set-up data by comparing this consecutive cohort of patients, to patients in standard closed masks treated during the same time period. Our standard institutional IGRT protocol includes daily CBCT for first 3 fractions, followed by weekly CBCT. The one-dimensional standard deviations (SD) of the systematic and random set-up errors were calculated for all three orthogonal directions (<i>x, y, z</i>). Mann-Whitney U and independent t-test were used to determine any significant differences between rotational set up data for open and closed masks. <h3>Results</h3> Sixty patients were included. Thirty patients had closed masks and thirty had open masks. The SD of the systematic error (reproducibility of treatment position) in mm was slightly less for closed mask than for the open mask in all directions (vertical 0.079 vs 0.106, lateral 0.068 vs 0.101, longitudinal 0.054 vs 0.080). The SD of the random error was less for closed than for open mask in vertical, 0.219 vs 0.225, and lateral,0.144 vs 0.174, directions. It was slightly more in the longitudinal direction (0.176 compared to 0.171). The margin requirements for the faceless mask were greater than the full mask. Margins for set-up uncertainty were 3.5, 3, and 3mm (Ant Post, Sup Inf and Right Left, respectively) for closed mask, and 4, 3, and 4mm respectively for open mask. There was no significant difference in pitch, roll and yaw between open and closed masks. <h3>Conclusion</h3> In this study, we have shown that open masks are able to maintain accuracy at levels comparable to closed masks and may be offered to patients suffering mask anxiety. However, a slightly larger PTV margin may be required. For open masks to become the standard of care for all head and neck patients, a larger randomized study should be performed. Customized head rests and real time intrafraction monitoring using 3-dimensional surface imaging could also be an advantage for this cohort of patients.

Assessment of IMPT versus VMAT plans using different uncertainty scenarios for prostate cancer

BackgroundTo assess the impact of systematic setup and range uncertainties for robustly optimized (RO) intensity modulated proton therapy (IMPT) and volumetric modulated arc therapy (VMAT) plans in patients with localized prostate cancer.MethodsTwenty-six localized prostate patients previously treated with VMAT (CTV to PTV expansion of 3-5 mm) were re-planned with RO-IMPT with 3 mm and 5 mm geometrical uncertainties coupled with 3% range uncertainties. Robust evaluations (RE) accounting for the geometrical uncertainties of 3 and 5 mm were evaluated for the IMPT and VMAT plans. Clinical target volume (CTV), anorectum, and bladder dose metrics were analyzed between the nominal plans and their uncertainty perturbations.ResultsWith geometric uncertainties of 5 mm and accounting for potential inter-fractional perturbations, RO-IMPT provided statistically significant (p < 0.05) sparing at intermediate doses (V4000cGy) to the anorectum and bladder and high dose sparring (V8000cGy) to the bladder compared to VMAT. Decreasing the RO and RE parameters to 3 mm improved IMPT sparing over VMAT at all OAR dose levels investigated while maintaining equivalent coverage to the CTV.ConclusionsFor localized prostate treatments, if geometric uncertainties can be maintained at or below 3 mm, RO-IMPT provides clear dosimetric advantages in anorectum and bladder sparing compared to VMAT. This advantage remains even under uncertainty scenarios. As geometric uncertainties increase to 5 mm, RO-IMPT still provides dosimetric advantages, but to a smaller magnitude.

Social Sustainability and Resilience in Supply Chains of Latin America on COVID-19 Times: Classification Using Evolutionary Fuzzy Knowledge

The number of research papers interested in studying the social dimension of supply chain sustainability and resilience is increasing in the literature. However, the social dimension is complex, with several uncertainty variables that cannot be expressed with a traditional Boolean logic of totally true or false. To cope with uncertainty, Fuzzy Logic allows the development of models to obtain crisp values from the concept of fuzzy linguistic variables. Using the Structural Equation Model by Partial Least Squares (SEM-PLS) and Evolutionary Fuzzy Knowledge, this research aims to analyze the predictive power of social sustainability characteristics on supply chain resilience performance in the context of the COVID-19 pandemic with representative cases from Mexico and Chile. We validate our approach using the Chile database for training our model and the Mexico database for testing. The fuzzy knowledge database has a predictive power of more than 80%, using social sustainability features as inputs regarding supply chain resilience in the context of the COVID-19 pandemic disruption. To our knowledge, no works in the literature use fuzzy evolutionary knowledge to study social sustainability in correlation with resilience. Moreover, our proposed approach is the only one that does not require a priori expert knowledge or a systematic mathematical setup.

A feasibility and pilot study of the clinical efficacy of a custom designed handgrip device to improve patient immobilisation for the external beam radiotherapy of oesophageal cancers

The primary aim of radiotherapy is to eradicate tumour cells within the clinical target volume (CTV), at the same time while sparing surrounding organs at risk (OAR) which is often accomplished by conforming to the treatment fields, i.e. target volume and by using appropriate margins for accounting the treatment uncertainties. Furthermore, for accurate radiation dose delivery, perfect immobilisation is required to keep the patient within the same position at each treatment fraction. There has always been a need for perfect immobilisation which should provide minimal patient movement, patient comfort, reproducible patient positioning during radiotherapy and be less expensive. The main objective of the present study was to design, fabricate and evaluate a handgrip board immobilisation device for the thorax region to boost the efficiency of the external beam radiotherapy in oesophageal cancer patients and evaluate the set-up error. Our indigenously fabricated handgrip baseboard device is made of poly-methyl methacrylate (PMMA), which consists of the main baseboard with an adjustable central T-bar and separate right and left single hand poles. In the present study, fifteen patients with oesophageal tumours were included. Patients were positioned using the indigenously fabricated handgrip immobilisation device; portal images were performed prior to the treatment and matched with the digitally reconstructed radiographs (DRR). The population systematic (Σ) and random (σ) patient set-up errors were calculated along the direc­tions of Anterior-Posterior (AP), Medial-Lateral (ML) and Superior-Inferior (SI). The values for the planning target volume (PTV) margins were calculated using ICRU 62, Van Herk’s and Stroom’s formulae. The population systematic (Σ) errors of AP, ML and SI were 0.12, 0.20 and 0.20 cm, respectively while the population random (σ) errors of AP, ML, SI were 0.17, 0.31 and 0.17 cm, respectively. The PTV margins were calculated according to ICRU 62, Van Herk’s, and Stroom’s and it was observed in the range of 0.2–0.7 cm in the three acquisition directions. The use of a handgrip immobilisation device allowed for relatively small set-up errors and ensured the patient’s comfort. Also, the technique showed satisfactory accuracy and reproducibility.

Old timber plantations and secondary forests attain levels of plant diversity and structure similar to primary forests in the West African humid tropics

Considering the high rate of primary forest degradation and loss in the tropics, the ability to conserve plant diversity within alternative forest landscape components is critical to biodiversity conservation. This study compares the restoration potential of old forest plantations and secondary forests. We assessed and compared the floristics, plant species diversity, conservation value, and structure of old (42–47 years) timber plantations ofAucoumea klaineana Pierre,Cedrela odorata L.,Tarrietia utilis Sprague, andTerminalia ivorensis A. Chev. and similar-aged secondary forests with nearby primary (old-growth) forests in the moist and wet forest zones of Ghana.We established a systematic sampling set-up of ninety-three 20 m × 20 m plots in total on 11 sites, with smaller nested subplots for saplings and ground vegetation.The floristic composition of the plantation and secondary forest stands were similar to that of the primary forests, with many rare and restricted-range species shared by the three forest types. Approximately 77% and 60% of primary forest plant species also occurred in plantation and secondary forests, respectively. Species diversity, measured by the Shannon-Wiener Diversity Index (H’) and Simpson Index (S), for the primary forest (H’=3.07, S = 0.91) was not statistically different from the plantation (H’=2.85, S = 0.87) or secondary (H’=2.95, S = 0.88) forests. Overall, species richness was higher in the primary and secondary forests compared to the plantations. At the tree stratum (≥10 cm DBH), the assessed diversity indices were significantly different between the primary forest and the plantations. However, such differences did not exist among the saplings (10 cm > DBH ≥ 2 cm) and ground vegetation (<2cm DBH). The plantations and secondary forests were similar to the primary forests for all the structural characteristics assessed. However, basal area and bole volume were significantly higher in the plantations compared with secondary forests. Conservation value (using Genetic Heat Index as an indicator) was highest in one of the C. odorata plantations (W-CO).Our study demonstrates that plantation and secondary forests can develop into structurally complex and floristically diverse self-organized stands similar to primary forests. Passive conversion of plantations to more natural ecosystems is an effective and low-cost forest restoration strategy leading to diverse ecosystems with high conservation value.

Retrospective study of random and systematic errors in Head and Neck cancer Patients with Image guided Helical Intensity Modulated Radiation Therapy

The Precision of radiotherapy is checked based on the matching of pre-treatment 2D portal imaging/CBCT to the reference image. The objective of this study is to find inter-fractional systematic and random setup errors (mm) for head and Neck cancer patients and also find setup margin for Planning Target Volume (PTV) at Mohan Dai Oswal Cancer Hospital Ludhiana Punjab. Inter-fractional motion errors were quantified for 10 Head and neck cancer patients who underwent image guided helical intensity modulated radiation therapy with Radixact X9 machine. One hundred fan beam computed tomography scans of 2mm slice thickness, 3.5 MV average energy and flattening filter free beam has been used to collect the data for the calculation of systematic and random errors. After patient immobilization, patient accuracy is checked with registration of pre-treatment image with reference planning image with the help of Accuray Precision image guidance protocol. For every patient 10 fan beam computed tomography images has been taken. Translational errors have been calculated in X, Y and Z direction to find systematic error (∑) and random error (σ). The final PTV margin is calculated by van Herk’s equation (2.5∑ + 0.7σ). The results of this study shows that mean translational errors varies from -2.3 mm to 3.3 mm in lateral direction (X), -3.6 mm to 1.7 mm in longitudinal direction (Y), -2.7 mm to 1.5 mm in vertical direction (Z). The mean and standard deviation (SD) for systematic errors are 1.467, 0.8, 0.923 and random error 0.0595, 0.02266, 0.03824 in X, Y and Z direction has been calculated. The Total Margin for CTV to PTV which include setup margin (mm) in X, Y and Z direction are 3.7 mm, 2.02 mm and 2.33 mm. In addition to that, a PTV margin of 5.00 mm is the appropriate margin for Mohan Dai Oswal Cancer Hospital’s patients. This work conclude that CTV to PTV margin of 5.00 mm is suitable for image guided helical intensity modulated radiation therapy for Head and neck patients to ensure the minimum 95% coverage of dose to target

Proceedings to the 7th Annual Conference of the Particle Therapy Cooperative Group North America (PTCOG-NA)

Proceedings to the 7th Annual Conference of the Particle Therapy Cooperative Group North America (PTCOG-NA)

Evaluation of image-guided and surface-guided radiotherapy for breast cancer patients treated in deep inspiration breath-hold: A single institution experience.

Nowadays, deep inspiratory breath-hold is a common technique to reduce heart dose in left-sided breast radiotherapy. This study evaluates the evolution of the breath-hold technique in our institute, from portal imaging during dose delivery to continuous monitoring with surface-guided radiotherapy (SGRT). Setup data and portal imaging results were analyzed for 98 patients treated before 2014, and SGRT data for 228 patients treated between 2018 and 2020. For the pre-SGRT group, systematic and random setup errors were calculated for different correction protocols. Residual errors and reproducibility of breath-holds were evaluated for both groups. The benefit of using SGRT for initial positioning was evaluated for another cohort of 47 patients. Online correction reduced the population mean error from 3.9mm (no corrections) to 1.4mm. Despite online setup correction, deviationsgreater than3mm were observed in about 10% and 20% of the treatment beams in ventral-dorsal and cranial-caudal directions, respectively. However, these percentages were much smaller than with offline protocols or no corrections. Mean absolute differences between breath-holds within a fraction were smaller in the SGRT-group (1.69mm) than in the pre-SGRT-group (2.10mm), and further improved with addition of visual feedback (1.30mm). SGRT for positioning did not improve setup accuracy, but slightly reduced the time for imaging and setup correction, allowing completion within 3.5min for 95% of fractions. For accurate radiotherapy breast treatments using deep inspiration breath-hold, daily imaging and correction is required. SGRT provides accurate information on patient positioning during treatment and improves patient compliance with visual feedback.

Detection of Vibration Induced Fatigue Crack Propagation Using a Hybrid Method

This paper demonstrates a simple technique to detect vibration-induced fatigue cracks using a hybrid method by vibration and acoustic emission techniques. A thin aluminum plate of 6082-T6 was excited using a vibration shaker to achieve a bending mode where the maximum stress exhibited at the plate mid-span. To simulate crack formation, a sharp notch was created. This systematic setup allows mode I crack propagation through plate thickness. The development of cracks over time changed the natural frequency of the plate which leads to the reduction of vibration amplitudes. This experimental technique facilitates the identification of acoustic emission waves during the onset of damage in the presence of noise due to dynamic motion. The effect of crack development on Lamb waves was investigated. The acoustic emission signals were cross-correlated with a Gaussian window of a central frequency of 250kHz. The results show a reduction in the fundamental wave A0, whilst an increase in S0 wave amplitudes at some stages during crack extension. The current experimental work can be an alternative technique for vibration-induced fatigue test evaluation.

Evaluation of setup errors of immobilization device for radiation therapy in companion animals.

Intensity-modulated radiotherapy (IMRT), which allows generating steep dose gradients, is a beneficial treatment for companion animals with adjacent target and risk organs. IMRT is essential for high setup accuracy for avoiding overdose to risk organs, and optimal radiotherapy is important for evaluating the setup accuracy of companion animals. To use an immobilization device to evaluate setup errors in radiotherapy for companion animals. We calculated setup errors in radiotherapy for 386 animals (dogs and cats; 3,261 registration images) that underwent radiotherapy between 2016 and 2022. The companion animals were immobilized with a customized bite block and vacuum lock device. A quantile-quantile plot with 95% confidence interval (CI) was used to evaluate the histogram of the setup errors, and the systematic and random setup errors were calculated for each region (brain, head and neck, chest and abdomen, pelvis, and spine). The setup error in each direction presented an extremely narrow-interval histogram, with the following lower and upper 95% CIs: cranial-caudal (-0.08, -0.06 cm); left-right (-0.04, -0.02 cm); and dorsal-ventral (-0.13, -0.11 cm). The mean systematic setup error was 0.16 cm (range: 0.12-0.36 cm), and the random error was 0.15 cm (range: 0.08-0.34 cm). The pelvis showed the highest systematic and random setup errors (mean: 0.36 and 0.23 cm, respectively). The use of an immobilization device enables highly accurate radiotherapy for companion animals (95% CI < 0.15 cm).

Is it beneficial to use apertures in proton radiosurgery with a scanning beam? A dosimetric comparison in neurinoma and meningioma patients.

PurposeTo assess the dosimetric advantages of apertures in intracranial single fraction proton radiosurgery.Materials and methodsSix neuroma and 10 meningioma patients were investigated. For each patient, six plans were computed, with two spot spacing and three aperture settings (no apertures, 5 and 8 mm margin between aperture and clinical target volume [CTV]). All plans were optimized on the CTV with the same beam arrangement and the same single‐field robust optimization (2 mm setup errors, 3.5% range uncertainties). Robustness analysis was performed with 0.5 and 1.0 mm systematic setup errors and 3.5% range uncertainties. CTV coverage in the perturbed scenarios and healthy brain tissue sparing in the surrounding of the CTV were compared.ResultsMeningiomas were larger and at a shallow depth than neuromas. In neuromas, spot spacing did not affect OAR doses or the robustness of CTV coverage and the apertures reduced brain dose without any significant impact on CTV robustness. In meningiomas, smaller spot spacing produced a reduction in brain V5Gy and improved robustness of CTV coverage; in addition, an 8 mm margin aperture reduced low and medium brain tissue doses without affecting robustness in the 0.5 mm perturbed scenario. A 5 mm margin aperture caused a reduction of plan robustness.ConclusionThe optimal use of apertures is a trade‐off between sparing of low and medium dose to the healthy brain and robustness of target coverage, also depending on size and depth of the lesion.