Planning System Research Articles

Commissioning and validation of a single photon beam model in RayStation for multiple matched Elekta Linacs.

A single treatment planning system (TPS) model for matched linacs provides flexible clinical workflows from patient treatment to intensity-modulated radiation therapy (IMRT) quality assurance (QA) measurement. Since general guidelines for building a single TPS model and its validation for matched linacs are not well established, we present our RayStation photon TPS modeling strategy for matched Elekta VersaHD linacs. The four linacs installed from 2013 to 2020 were matched in terms of Percent Depth Dose (PDD), profile, output factor and wedge factors for 6-MV, 10-MV, 15-MV, and 6-MV-FFF, and maintained following TG-142 recommendations until RayStation commissioning. The RayStation single model was built to represent all four linacs within the tolerance limits recommended by MPPG-5.a. The comprehensive validation tests were performed for one linac following MPPG-5.a and TG-119 guidelines, and spot checks for the other three. Our TPS modeling/validation method was evaluated by re-analyzing the previous 103 patient-specific IMRT/volumetric modulated arc therapy (VMAT) QA measurements with the calculated planar doses by the single model in comparison with the analysis results using four individual Pinnacle TPS models. For all energies, our single model PDDs were within 1% agreement of the four-linac commissioning measurements. The MPPG-5.a validation tests from 5.1 through 7.5 and all TG-119 measurements passed within the recommended tolerance limits. The IMRT QA results (mean±standard deviation) for RayStation single model versus Pinnacle individual models were 98.9%±1.3% and 98.0%±1.4% for 6-MV, 99.9%±0.1% and 99.1%±1.9% for 10-MV, and 98.2%±1.3% and 97.9%±1.8% for 6-MV-FFF, respectively. We successfully built and validated a single photon beam model in RayStation for four Elekta Linacs. The proposed new validation methods were proven to be both efficient and effective.

Comprehensive clinical implementation, workflow, and FMEA of bespoke silicone bolus cast from 3D printed molds using open-source resources.

Bolus materials have been used for decades in radiotherapy. Most frequently, these materials are utilized to bring dose closer to the skin surface to cover superficial targets optimally. While cavity filling, such as nasal cavities, is desirable, traditional commercial bolus is lacking, requiring other solutions. Recently, investigators have worked on utilizing 3D printing technology, including commercially available solutions, which can overcome some challenges with traditional bolus. To utilize failure modes and effects analysis (FMEA) to successfully implement a comprehensive 3D printed bolus solution to replace commercial bolus in our clinic using a series of open-source (or free) software products. 3D printed molds for bespoke bolus were created by exporting the DICOM structures of the bolus designed in the treatment planning system and manipulated to create a multipart mold for 3D printing. A silicone (Ecoflex 00-30) mixture is poured into the mold and cured to form the bolus. Molds for sheet bolus of five thicknesses were also created. A comprehensive FMEA was performed to guide workflow adjustments and QA steps. The process map identified 39 and 30 distinct steps for the bespoke and flat sheet bolus workflows, respectively. The corresponding FMEA highlighted 119 and 86 failure modes, with 69 shared between the processes. Misunderstanding of plan intent was a potential cause for most of the highest-scoring failure modes, indicating that physics and dosimetry involvement early in the process is paramount. FMEA informed the design and implementation of QA steps to guarantee a safe and high-quality comprehensive implementation of silicone bolus from 3D printed molds. This approach allows for greater adaptability not afforded by traditional bolus, as well as potential dissemination to other clinics due to the open-source nature of the workflow.

Controller Synthesis for Timeline-based Games

In the timeline-based approach to planning, the evolution over time of a set of state variables (the timelines) is governed by a set of temporal constraints. Traditional timeline-based planning systems excel at the integration of planning with execution by handling temporal uncertainty. In order to handle general nondeterminism as well, the concept of timeline-based games has been recently introduced. It has been proved that finding whether a winning strategy exists for such games is 2EXPTIME-complete. However, a concrete approach to synthesize controllers implementing such strategies is missing. This paper fills this gap, by providing an effective and computationally optimal approach to controller synthesis for timeline-based games.

CONSIDERATION OF PLANNING PERMISSION IN SHORT-TERM RESIDENTIAL ACCOMMODATIONS

Planning permission may be required if the use of the property for short-term residential accommodations (STRA) services constitutes ‘development’ in planning terms. In analysing the possible operational aspects of STRA application in the planning system in Malaysia, the experience of STRA implementation in some selected countries is explored. The article concludes that there are different approaches, which are adopted by different regions concerning the need for planning permission. Most jurisdictions that are “friendly” towards STRAs view that planning permission is not necessary if STRA is managed on a small scale. Hence, it can be concluded that if the scale of the STRA business is big, i.e. ‘commercial’ in nature, planning permission is needed. Alternatively, the local planning authority may consider issuing a provisional or temporary planning permission (TPP), a short-term approval that is only permissible for the transitory nature of the use of land and buildings.

Regional Security, Problems and Influencing Factors: A Case Study of Albania

The new national, regional and global security environment and its trends are expressed in a synthesized way in the National Security Strategy. Our region is increasingly characterized, on the one hand, by overcoming the old mindsets of confrontation between states and the perceptible reduction of traditional threats, by the promotion of a new spirit of cooperation and the values of integration in the collective security structures and on the other hand, it is facing a new nature of challenges, dangers and threats with non-traditional, asymmetric forms and contents, on terrorist, ethnic or other grounds, initiated by nationalist-extremist elements and groups. Receiving the long-awaited invitation to the Bucharest Summit in April 2008, as well as the final moment for NATO accession at the NATO Summit in Stratsburg and Kehl, marks a qualitative stage in the complete process of Albania in the Euro-Atlantic structures. In this new perspective, the security and defense of our country will suffer qualitative effects; from the concept of individual security and protection, it will finally be passed "de jure" to the concept of collective security and protection, accompanied by all the relevant benefits and contributions. Likewise, the new states of Kosovo and Montenegro have given our region a new favorable panorama of regional security. Going forward, our assessments of the security environment, expected risks and threats, and the spectrum of FARSH combat and non-combat missions will be significantly influenced by the collective security assessments articulated in the Alliance's Strategic Concept (CSC), Policy of European Security and Defense (ESDP) and the Charter of the United Nations. In this new perspective, in full accordance with the constitutional obligations, FARSH to adopt a new defense planning system, in harmony with the standards and planning processes of the Euro-Atlantic Alliance. Keywords: Influencing factors, Regional security, NATO, National security

Contribution of congested traffic flow condition to air pollution at intersections in Addis Ababa, Ethiopia

Currently, one of the serious problems in the world is transport-related air pollution. Air pollution from vehicles was not considered properly in the plan, design, and management system of the roads in Addis Ababa city, to solve the problem of traffic congestion. It is influenced by different factors such as road geometry, road surface type, traffic congestion, traffic characteristics, fuel type, and meteorological parameters. This study was aimed to investigate the contribution of congested traffic flow conditions on air pollution at intersection points in Addis Ababa city. To carry out the study, seven intersection points were selected in the city randomly. For the measurement technique of carbon monoxide (CO) and sulfur dioxide (SO2) gases, a portable Aeroqual series 500 instrument was exercised, and for the particular matter (PM2.5 and PM10), Light Amplification by Stimulated Emission of Radiation (LASER) was adapted. To count the number of traffic on the site, a video camera method was utilized. For the data analysis techniques, a multiple linear regression method was practiced, which is very powerful for multiple independent variables with a single dependent one. The study revealed that the level of traffic congestion at each selected intersection is at a severe level. During the congested time, as a base of the steady condition, the pollutants concentration of CO, SO2, PM2.5, and PM10 were increased by an average of 19.10, 51.61, 33.83, and 29.07 % respectively. Based on the analyzed results, when the concentration of pollutants increases, the traffic volume, percentage of heavy vehicles, green time, and approach grade are also increased. On the other hand, the concentration of pollutants decreased when the lane width and wind speed increased. Therefore, any concerned bodies in and around Addis Ababa city should take remedial measures to decrease the emission of the concentration of the pollutants. This investigation is very important for policymakers, municipalities, and planners to do any activities in the city. Researchers can also use it as a reference, for further investigations and remedial measurements.

Resilience to wildfires: Comparative insights of barriers and facilitators for spatial planning in Victoria and Chile

This paper explores the elements influencing and conditioning spatial planning processes for changing their systems based on new wildfire information. The research was approached as an inductive qualitative research, using a multiple case study strategy: the Chilean and the Victorian (Australia) spatial planning systems. The analysis considered the barriers and facilitators for change (willingness, understandings, and capacities), and the stages of processes of knowledge development for changing the spatial planning systems (identification, reframing, and implementation). Based on a cross-case synthesis of the two case studies, analytic generalizations about spatial planning's ability to change its instruments and practices for dealing with wildfires, and elements conditioning this ability, are suggested in the form of theoretical propositions: three overarching propositions, broken down into ten propositions specific to the stages of the process of knowledge development and change. These provide applied understandings of spatial planning mechanisms and processes that hinder or contribute to changing their instruments for dealing with wildfires. Furthermore, they suggest that the success of knowledge development and change processes requires the acceptance and use of the willingness, understanding, and capacity dynamics. Ultimately, this research contributes theoretical and practical insights for promoting wildfire resilience via the planning and governance of cities.

An innovative integrated framework for multi-level production planning and control systems in construction

The construction industry is plagued by chronic inefficiencies, such as low productivity, significant waste, cost overruns, and schedule delays. One of the most critical contributors to these issues is fragmented and ineffective planning and control methods. This research aims to address these challenges by developing an innovative integrated multi-level framework for production planning and control that harmonizes various planning methods and control metrics across different schedule levels. Employing the Design Science Research (DSR) methodology, this study systematically develops and evaluates an innovative framework that integrates internal and external project characteristics, utilizing the concept of "functionality" as a primary key for coherent integration. Furthermore, a multi-objective mathematical model is incorporated to clarify the framework's components and optimize the number of suggested planning methods and control metrics at each scheduling level, aiming to balance the functional requirements of project teams with the practicality of implementation.The application of the framework to a renovation case study demonstrates its practicality and strategic value, effectively addressing real-world project management challenges. Moreover, industry and academic evaluations highlight its potential to significantly improve construction project management practices.

Transfer learning-based nonstationary traffic flow prediction using AdaRNN and DCORAL

Traffic flow prediction is an integral part of an intelligent transportation system (ITS) for proactive transportation planning and management in public transit network systems. However, due to the influence of passengers’ travel modes and the difficulty of data collection, some traffic flow datasets are not only nonstationary in temporal distribution but also insufficient in data size, leading to inaccurate prediction results. Therefore, a transfer learning-based method is proposed to predict nonstationary traffic flow with inadequate data in the public transit system. In the proposed model, a novel approach named AdaRNN-DCORAL is presented to achieve accurate traffic flow prediction in the temporal dimension. Specifically, AdaRNN is an adaptive prediction network for nonstationary traffic flow data, while DCORAL performs domain adaptation between the source and target domain in the public transit system. First, two domains of traffic flow datasets in two public transit modes are established, which are the target domain with insufficient data and the source domain with sufficient data. Subsequently, the traffic flow datasets are divided into weekday and holiday time series based on their distribution characteristics. On this basis, AdaRNN-DCORAL is trained on the constructed datasets, thus achieving the precise nonstationary prediction of data scarcity in the target domain. Finally, the experiments demonstrate the improved performance of the proposed method over that of state-of-the-art models in terms of prediction accuracy and computation time.

Equivalent Survivorship of Total Hip Arthroplasty in Patients Who Have Inflammatory Bowel Disease

BackgroundInflammatory bowel disease (IBD) can have orthopaedic manifestations related to decreased bone mineral density and increased fracture risk. The impact of IBD-spectrum diseases, including Crohn’s disease (CD) and ulcerative colitis (UC), on the overall performance of total hip arthroplasty (THA), is not well understood. The present study sought to evaluate whether patients who have IBD were at an increased risk of THA failure compared to those who did not have IBD. MethodsThe Statewide Planning and Research Cooperative System was used to compare postoperative outcomes between patients who have IBD (CD and UC) and patients who do not have IBD from 2010 to 2020. A total of 119,094 patients were included in the study, of whom 1,165 had a diagnosis of IBD. Overall, 501 of those had CD, while 664 had UC. ResultsWhen controlling for comorbidities, patients who had CD had longer hospital length of stay (CD: 3.6 ± 2.5 versus UC: 3.4 ± 2.1 versus control: 3.2 ± 2.3 days, P < 0.001), higher rates of 90-day readmission (CD: 13.6 versus UC: 8.3 versus control: 7.7%, P < 0.001) and 1-year readmission (CD: 20.4 versus UC: 15.1 versus control: 12.8%, P < 0.001), and higher rates of 90-day emergency room visits (CD: 15.4 versus UC: 12 versus control: 11.1%, P = 0.007). There were no differences in all-cause revision or revision for periprosthetic joint infection between CD and UC compared with control patients. ConclusionsPatients who have UC had more emergency room visits and hospital readmissions following THA; however, survival analysis demonstrated that IBD patients are not at an increased risk of revision or periprosthetic joint infection after THA.

Comparative study on three-dimensional versus two-dimensional imaging using a computer-assisted surgery system for preoperative planning in pediatric middle hepatic tumors

BackgroudThe study objective was to compare three-dimensional and two-dimensional imaging using computer-assisted systems (CASs) in clinical guidance for preoperative surgical planning for middle hepatic tumors in children.MethodsA retrospective analysis was performed on 23 children who underwent surgery for middle hepatic tumors in our hospital from January 2016 to June 2022. The surgical resection plan was formulated by the operator team using two-dimensional CT images before the operation. Then, the same qualified surgeons conducted an in-depth analysis and formulated the surgical resection scheme for the same pediatric patient using three-dimensional imaging of the middle hepatic tumor. The feasibility of the two schemes was compared and analyzed.ResultAll the tumors were successfully removed according to the preoperative method developed using three-dimensional imaging. The postoperative short-term follow-up revealed that all patients were doing well. Preoperative plans were revised in 9 cases after evaluating the three-dimensional images due to the disparity between the original plans and the three-dimensional relationship between the tumor and blood vessels, vascular variation, and the volume of remnant liver.ConclusionsThree-dimensional imaging with a computer-assisted surgery system is superior to two-dimensional imaging in the preoperative planning of pediatric hepatoblastoma.

A novel x-Ray and γ-Ray combination strategy for radiotherapy after breast-conserving surgery in patients with right breast cancer.

Radiotherapy is a primary therapeutic approach for breast cancer following breast-conserving surgery. The TaiChiB dual-modality radiotherapy system combining X-ray and focused γ-ray, offers a new approach to reduce the radiation dose of organs at risk (OARs) and has the potential to mitigate the adverse effects of radiotherapy. Currently, there are few studies on the dosimetric characteristics of the TaiChiB dual-modality system for actual treatment plans for specific diseases. The purpose of this work is to study the dosimetric advantages of dual-modal systems for right breast patients after breast-conserving surgery. Treatment plans for 20 patients with right breast cancer were generated for a linear accelerator (LINAC) based system and the TaiChiB dual-modality system, respectively. Volumetric modulated arc therapy plans with simultaneous integrated boost (VMAT-SIB) were made for the LINAC. Focused γ-ray was used to deliver the boost dose with the dual-modality system. The dosimetric parameters of the target and OARs were evaluated and compared between the treatment plans generated for the two systems. The TaiChiB dual-modality plans exhibit a higher conformal index (CI) and lower gradient index (GI) for the PGTV and PTV compared with the LINAC-based VMAT-SIB plans. Compared to VMAT-SIB plans, the PTV Dmax, PTV Dmean, PTV V110, PGTV Dmax, and PGTV Dmean of the TaiChiB dual-modality plans are significantly lower. Meanwhile, the dose to OARs, such as the Dmean of the heart, the V5 of liver, the Dmean of ipsilateral lung, the V30 of ipsilateral lung, the V20 of ipsilateral lung, the V5 of ipsilateral lung, the Dmean of contralateral lung, Dmax of contralateral breast and the Dmean of contralateral breast are significantly reduced. Our study demonstrates the dosimetric advantages of the novel TaiChiB dual-modality radiotherapy system for the treatment of right-sided breast cancer. Overall, for the TaiChiB dual-modality radiotherapy system, the radiation dose outside the target region decreases rapidly, thereby minimizing radiation exposure to neighboring organs and ensuring the conformity of the target area. Our research confirms the potential of the TaiChiB dual-modality system for future radiotherapy.

How urban–rural differences and ageing affect residents’ occupancy patterns – An empirical study based on China national time use survey

Occupancy behavior plays a crucial role in residential community planning, building design, and energy system optimization for sustainable development, particularly in the face of climate change. Research on residential occupancy behavior often lacks comprehensive empirical data and fails to account for the diversity of influencing factors such as demographic features and urban–rural distinctions. This study utilizes a national time-use survey to examine occupancy patterns in urban and rural households, aiming to identify key factors influencing these patterns. A K-shaped cluster analysis was applied to extract typical occupancy patterns for weekdays and weekends, with a subsequent comparison between urban and rural data. The study also analyzed the impact of demographic and social factors on total hours spent at home. The results indicate that urban residents tend to concentrate their occupancy on weekdays, while weekends show more dispersed patterns. Furthermore, time spent at home by urban residents is positively correlated with the age of family members and negatively correlated with working status and education level. Given the aging demographic, older urban families are likely to spend more time at home on weekdays. These findings contribute to a better understanding of residential occupancy behavior in China.

Research on energy consumption optimization of predictive cruise control considering the state of the leading vehicle

To comprehensively assess the economic performance of electric vehicles (EVs) cruise planning and mitigate conflicts with leading vehicles, a dynamic programming-based predictive cruise speed optimization control system was developed. This system comprises two layers: an upper V2X-based LSTM-DP cruise speed planning system and a lower adaptive cruise control system based on sliding mode control (SMC), and the mode switching strategy of the speed and distance tracking controller is designed. Initially, a segmented uniform variable motion algorithm processed the historical driving data of the leading vehicle, significantly enhancing the LSTM neural network's acceleration prediction capability, particularly on inclines, with an improvement in accuracy of 37.8 %. Subsequently, an adaptive cruise tracking controller was implemented to track the planned vehicle speed. Simulation tests on actual roads demonstrated that the LSTM-DP approach not only ensures driving safety but also markedly improves fuel efficiency over conventional constant speed cruising methods when planning is effective. Moreover, even in scenarios where planning fails, the LSTM-DP strategy can still achieve energy savings of up to 37 % without compromising the safety distance between vehicles. Finally, hardware-in-the-loop (HIL) testing confirmed the system's efficacy under real-time operational conditions.

From Rational Planning to Communicative Planning: Exploring the Roles of Responsible Planners in Beijing

Problem, research strategy, and findings Thirty-two of China’s largest cities have implemented community planner policies. Scholars have debated whether these initiatives have accelerated China’s urban planning system transition from more rational to communicative planning. Through a survey and 23 interviews, we investigated the role tendencies and motivators of a typical example of community planners, known in Beijing as responsible planners. We developed a typology delineating three roles of responsible planners: technical expert, advocate planner, and communicative planner. Results suggest that responsible planners frequently play hybrid roles, yet they exhibit a limited understanding of their role as communicative planners. Graduate planning education in China has tended to stereotype responsible planners as technical experts. Institutional design requiring public participation reduces reliance on technical experts. Responsible planners’ understanding their roles differ significantly from planning practices in North America. The qualitative interviews further illuminated these differences and unraveled the complex motivators in responsible planners’ role choices within the Chinese context. Takeaway for practice Planning authorities and educators should highlight policies advocating for public participation, graduate planning education emphasizing social planning, and continuing professional education featuring tutorials and knowledge sharing to facilitate a communicative turn in urban planning. This approach will empower planners to better serve residents.

Financial Technologies Impact on Higher Education Institution Budgeting and Financial Planning

This study investigates the impact of financial technologies on the budgeting and financial planning practices of private Higher Education Institutions (HEIs). The primary objectives are to identify the most adopted financial technologies, evaluate the extent of cash flow management practices, and assess the implementation of digital payment systems. Comparative research design was utilized in the study to determine the differences in perception between teaching staff (N = 50) and non-teaching staff (N = 50) regarding these technologies. Data were collected through surveys and analyzed to determine the levels of adoption and effectiveness of various financial technologies. The findings reveal that digital payment systems are the most widely adopted, followed by Oracle Financials and Enterprise Resource Planning (ERP) systems. HEIs demonstrate strong practices in revenue diversification, strategic budgeting, cost control, and financial reserve management. However, concerns about the accuracy of financial reporting indicate a need for improvement. Significant differences in perceptions and attitudes towards financial technologies were found between teaching and non- teaching staff, highlighting the necessity for targeted interventions. Based on these findings, a comprehensive financial technology plan is proposed, focusing on enhancing perceived use, improving ease of use, fostering positive attitudes, and increasing actual usage of financial technologies. The plan includes specific actions, responsibilities, and timelines to ensure effective implementation. This research underscores the importance of continuous investment in financial technologies and strategic planning to enhance financial management practices in HEIs. By addressing the identified gaps and leveraging existing strengths, institutions can achieve greater efficiency, accuracy, and innovation in their financial operations, ultimately leading to improved financial stability and performance. Keywords: Financial Technology, HEIs, Financial Planning, Budgeting

Clinician Specialty and HIV PrEP Prescription Reversals and Abandonments

Clinicians are a key component of preexposure prophylaxis (PrEP) care. Yet, no prior studies have quantitatively investigated how PrEP adherence differs by clinician specialty. To understand the association between prescribing clinician specialty and patients not picking up (reversal/abandonment) their initial PrEP prescription. This cross-sectional study of patients who were 18 years or older used pharmacy claims data from 2015 to 2019 on new insurer-approved PrEP prescriptions that were matched with clinician data from the US National Plan and Provider Enumeration System. Data were analyzed from January to May 2022. Clinician specialties included primary care practitioners (PCPs), infectious disease (ID), or other specialties. Reversal was defined as a patient not picking up their insurer-approved initial PrEP prescription. Abandonment was defined as a patient who reversed and still did not pick their prescription within 365 days. Of the 37 003 patients, 4439 (12%) were female and 32 564 (88%) were male, and 77% were aged 25 to 54 years. A total of 24 604 (67%) received prescriptions from PCPs, 3571 (10%) from ID specialists, and 8828 (24%) from other specialty clinicians. The prevalence of reversals for patients of PCPs, ID specialists, and other specialty clinicians was 18%, 18%, and 25%, respectively, and for abandonments was 12%, 12%, and 20%, respectively. After adjusting for confounding, logistic regression models showed that, compared with patients who were prescribed PrEP by a PCP, patients prescribed PrEP by ID specialists had 10% lower odds of reversals (odds ratio [OR], 0.90; 95% CI, 0.81-0.99) and 12% lower odds of abandonment (OR, 0.88; 95% CI, 0.78-0.98), while patients prescribed by other clinicians had 33% higher odds of reversals (OR, 1.33; 95% CI, 1.25-1.41) and 54% higher odds of abandonment (OR, 1.54; 95% CI, 1.44-1.65). The results of this cross-sectional study suggest that PCPs do most of the new PrEP prescribing and are a critical entry point for patients. PrEP adherence differs by clinician specialties, likely due to the populations served by them. Future studies to test interventions that provide adherence support and education are needed.

Evaluation of the conformity of intensity-modulated radiation therapy and volumetric modulated arc therapy using AAPM TG 119 protocol.

The aim of this work was to evaluate the conformity of intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT), and verify the accuracy of the planning and delivery system used in this work based on the AAPM TG-119 protocol. The Eclipse 13.6 treatment planning system (TPS) was used to plan the TG-119 test suite, which included four test cases: MultiTarget, Prostate, Head/Neck, and C-Shape for IMRT and VMAT techniques with 6 MV and 10 MV acceleration voltages. The results were assessed and discussed in terms of the TG-119 protocol and the results of previous studies. In addition, point dose and planar dose measurements were done using a semiflex ion chamber and an electronic portal imaging device (EPID), respectively. The planned doses of all test cases met the criteria of the TG-119 protocol, except those for the spinal cord of the C-Shape hard case. There were no significant differences between the treatment planning doses and the doses given in the TG-119 report, with p-values ranging from 0.974 to 1 (p > 0.05). Doses to the target volumes were similar in the IMRT and VMAT plans, but the organs at risk (OARs) doses were different depending on the test case. The planning results showed that IMRT is more conformal than VMAT in certain cases. For the point dose measurements, the confidence limit (CLpoint) of 0.030 and 0.021 were better than the corresponding values of 0.045 and 0.047 given in the TG-119 report for high-dose and low-dose areas, respectively. Regarding the planar dose measurements, the CLplanar value of 0.38 obtained in this work was lower than that given in the TG-119 report (12.4). It is concluded that the dosimetry measurements performed in this study showed better confidence limits than those provided in the TG 119 report. IMRT remains more conformal in certain circumstances than the more progressive VMAT. When selecting the method of delivering a dose to the patient, several factors must be considered, including the radiotherapy technique, energy, treatment site, and tumour geometry.

Analysis of the gamma index using an indigenously developed anthropomorphic heterogeneous female pelvis (AHFP) phantom.

It is essential in modern radiotherapy treatment practices to evaluate the quality assurance (QA) of the treatment plan prior to the exclusion of patient from treatment. The typical suitable tools used for patient pretreatment QA are phantoms representing the human anatomy. An anthropomorphic heterogeneous female pelvic (AHFP) phantom has been developed to represent the real female pelvic structure. The objective of the current study is to assess the findings of relative dosimetry carried out utilizing an electronic portal imaging device (EPID) on the AHFP phantom fabricated. The planning target volume (PTV) was created on CT slices of an AHFP phantom to confirm the tool's ability to represent female pelvic anatomy and serve as a QA tool. In order to assess the dose received by healthy organs during radiotherapy, organs at risk such as the bladder and rectum were additionally drawn alongside the PTV. Rapid Arc and Intensity modulated radiation therapy (IMRT) were both used to create the treatment plan on treatment planning system, and the Anisotropic Analytical Algorithm Version 11.0.31 was used to calculate the dose. The results obtained for the average gamma value in RapidArc plans are 0.26, 0.27, and 0.28 (g ≤1) and IMRT plans are 0.39, 0.40, and 0.46 (g ≤1) for target 1, target 2, and target 3, respectively. According to the findings of the current study, the AHFP phantom was used to explore the potential of relative dosimetry using EPID as a QA tool, which was found to be suitable.

Comparative analysis of delivered and planned doses in target volumes for lung stereotactic ablative radiotherapy

BackgroundAdaptive therapy has been enormously improved based on the art of generating adaptive computed tomography (ACT) from planning CT (PCT) and the on-board image used for the patient setup. Exploiting the ACT, this study evaluated the dose delivered to patients with non-small-cell lung cancer (NSCLC) patients treated with stereotactic ablative radiotherapy (SABR) and derived relationship between the delivered dose and the parameters obtained through the evaluation procedure.MethodsSABR treatment records of 72 patients with NSCLC who were prescribed a dose of 60 Gy (Dprescribed) to the 95% volume of the planning target volume (PTV) in four fractions were analysed in this retrospective study; 288 ACTs were generated by rigid and deformable registration of a PCT to a cone-beam computed tomography (CBCT) per fraction. Each ACT was sent to the treatment planning system (TPS) and treated as an individual PCT to calculate the dose. Delivered dose to a patient was estimated by averaging four doses calculated from four ACTs per treatment. Through the process, each ACT provided the geometric parameters, such as mean displacement of the deformed PTV voxels (Warpmean) and Dice similarity coefficient (DSC) from deformation vector field, and dosimetric parameters, e.g. difference of homogeneity index (ΔHI, HI defined as (D2%-D98%)/Dprescribed*100) and mean delivered dose to the PTV (Dmean), obtained from the dose statistics in the TPS. Those parameters were analyzed using multiple linear regression and one-way-ANOVA of SPSS® (version 27).ResultsThe prescribed dose was confirmed to be fully delivered to internal target volume (ITV) within maximum difference of 1%, and the difference between the planned and delivered doses to the PTV was agreed within 6% for more than 95% of the ACT cases. Volume changes of the ITV during the treatment course were observed to be minor in comparison of their standard deviations. Multiple linear regression analysis between the obtained parameters and the dose delivered to 95% volume of the PTV (D95%) revealed four PTV parameters [Warpmean, DSC, ΔHI between the PCT and ACT, Dmean] and the PTV D95% to be significantly related with P-values < 0.05. The ACT cases of high ΔHI were caused by higher values of the Warpmean and DSC from the deformable image registration, resulting in lower PTV D95% delivered. The mean values of PTV D95% and Warpmean showed significant differences depending on the lung lobe where the tumour was located.ConclusionsEvaluation of the dose delivered to patients with NSCLC treated with SABR using ACTs confirmed that the prescribed dose was accurately delivered to the ITV. However, for the PTV, certain ACT cases characterised by high HI deviations from the original plan demonstrated variations in the delivered dose. These variations may potentially arise from factors such as patient setup during treatment, as suggested by the statistical analyses of the parameters obtained from the dose evaluation process.