18 results on '"Yiannis Roussakis"'
Search Results
2. Personalised in silico biomechanical modelling towards the optimisation of high dose-rate brachytherapy planning and treatment against prostate cancer
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Myrianthi Hadjicharalambous, Yiannis Roussakis, George Bourantas, Eleftherios Ioannou, Karol Miller, Paul Doolan, Iosif Strouthos, Constantinos Zamboglou, and Vasileios Vavourakis
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in silico modelling ,meshless ,simulation ,brachytherapy ,radiotherapy ,drug delivery ,Physiology ,QP1-981 - Abstract
High dose-rate brachytherapy presents a promising therapeutic avenue for prostate cancer management, involving the temporary implantation of catheters which deliver radioactive sources to the cancerous site. However, as catheters puncture and penetrate the prostate, tissue deformation is evident which may affect the accuracy and efficiency of the treatment. In this work, a data-driven in silico modelling procedure is proposed to simulate brachytherapy while accounting for prostate biomechanics. Comprehensive magnetic resonance and transrectal ultrasound images acquired prior, during and post brachytherapy are employed for model personalisation, while the therapeutic procedure is simulated via sequential insertion of multiple catheters in the prostate gland. The medical imaging data are also employed for model evaluation, thus, demonstrating the potential of the proposed in silico procedure to be utilised pre- and intra-operatively in the clinical setting.
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- 2024
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3. School integration of refugee minors: An analysis of the barriers of education quality and continuity in Italian and Greek school systems
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Gül Ince-Beqo, Yiannis Roussakis, and Vittorio Sergi
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Law of Europe ,KJ-KKZ ,International relations ,JZ2-6530 ,Political science (General) ,JA1-92 ,Social sciences (General) ,H1-99 - Abstract
In recent years, the number of minor migrants, both accompanied and unaccompanied, arriving in European countries increased significantly. The impact of newcomers on the school systems of various European countries has highlighted problems in education continuity and in the accomplishment of educational goals. Relying on the preliminary data from the Erasmus+ KA2 project “Continugee” in Italy and Greece, this paper analyses the current policies and practices used in refugee children education. In addition to policy analysis, interviews with families, teachers and professionals operating in migrant shelters and schools were conducted, aimed to address both institutional and relational dimensions of schooling and to point out good practices in educational incorporation of refugee youth. Research shows that – notwithstanding a common concern throughout Europe, national and local regulations, and local practices do affect their access to quality education. Age limits, gender gaps, location of shelters, lack of adequate institutional educational facilities and of professional training make effective educational placement and continuity difficult. Schools have a very different level of effectiveness and European policy innovation is often jeopardized by lack of resources and staff motivation. Recognition of qualifications and skills, a supported participation into mainstream education, and a participatory approach with families and guardians are essential for effective school integration. Keywords: refugee, minors, education, training, policy, European
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- 2023
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4. A clinical evaluation of the performance of five commercial artificial intelligence contouring systems for radiotherapy
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Paul J. Doolan, Stefanie Charalambous, Yiannis Roussakis, Agnes Leczynski, Mary Peratikou, Melka Benjamin, Konstantinos Ferentinos, Iosif Strouthos, Constantinos Zamboglou, and Efstratios Karagiannis
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AI ,contouring ,radiotherapy ,breast ,head and neck ,lung ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Purpose/objective(s)Auto-segmentation with artificial intelligence (AI) offers an opportunity to reduce inter- and intra-observer variability in contouring, to improve the quality of contours, as well as to reduce the time taken to conduct this manual task. In this work we benchmark the AI auto-segmentation contours produced by five commercial vendors against a common dataset.Methods and materialsThe organ at risk (OAR) contours generated by five commercial AI auto-segmentation solutions (Mirada (Mir), MVision (MV), Radformation (Rad), RayStation (Ray) and TheraPanacea (Ther)) were compared to manually-drawn expert contours from 20 breast, 20 head and neck, 20 lung and 20 prostate patients. Comparisons were made using geometric similarity metrics including volumetric and surface Dice similarity coefficient (vDSC and sDSC), Hausdorff distance (HD) and Added Path Length (APL). To assess the time saved, the time taken to manually draw the expert contours, as well as the time to correct the AI contours, were recorded.ResultsThere are differences in the number of CT contours offered by each AI auto-segmentation solution at the time of the study (Mir 99; MV 143; Rad 83; Ray 67; Ther 86), with all offering contours of some lymph node levels as well as OARs. Averaged across all structures, the median vDSCs were good for all systems and compared favorably with existing literature: Mir 0.82; MV 0.88; Rad 0.86; Ray 0.87; Ther 0.88. All systems offer substantial time savings, ranging between: breast 14-20 mins; head and neck 74-93 mins; lung 20-26 mins; prostate 35-42 mins. The time saved, averaged across all structures, was similar for all systems: Mir 39.8 mins; MV 43.6 mins; Rad 36.6 min; Ray 43.2 mins; Ther 45.2 mins.ConclusionsAll five commercial AI auto-segmentation solutions evaluated in this work offer high quality contours in significantly reduced time compared to manual contouring, and could be used to render the radiotherapy workflow more efficient and standardized.
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- 2023
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5. Considerations for artificial intelligence clinical impact in oncologic imaging: an AI4HI position paper
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Luis Marti-Bonmati, Dow-Mu Koh, Katrine Riklund, Maciej Bobowicz, Yiannis Roussakis, Joan C. Vilanova, Jurgen J. Fütterer, Jordi Rimola, Pedro Mallol, Gloria Ribas, Ana Miguel, Manolis Tsiknakis, Karim Lekadir, and Gianna Tsakou
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Artificial intelligence ,Oncologic imaging ,Prediction models ,Clinical validation ,Medical physics. Medical radiology. Nuclear medicine ,R895-920 - Abstract
Abstract To achieve clinical impact in daily oncological practice, emerging AI-based cancer imaging research needs to have clearly defined medical focus, AI methods, and outcomes to be estimated. AI-supported cancer imaging should predict major relevant clinical endpoints, aiming to extract associations and draw inferences in a fair, robust, and trustworthy way. AI-assisted solutions as medical devices, developed using multicenter heterogeneous datasets, should be targeted to have an impact on the clinical care pathway. When designing an AI-based research study in oncologic imaging, ensuring clinical impact in AI solutions requires careful consideration of key aspects, including target population selection, sample size definition, standards, and common data elements utilization, balanced dataset splitting, appropriate validation methodology, adequate ground truth, and careful selection of clinical endpoints. Endpoints may be pathology hallmarks, disease behavior, treatment response, or patient prognosis. Ensuring ethical, safety, and privacy considerations are also mandatory before clinical validation is performed. The Artificial Intelligence for Health Imaging (AI4HI) Clinical Working Group has discussed and present in this paper some indicative Machine Learning (ML) enabled decision-support solutions currently under research in the AI4HI projects, as well as the main considerations and requirements that AI solutions should have from a clinical perspective, which can be adopted into clinical practice. If effectively designed, implemented, and validated, cancer imaging AI-supported tools will have the potential to revolutionize the field of precision medicine in oncology.
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- 2022
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6. Modelling the Collapsing University
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Vaia Papanikolaou, Yiannis Roussakis, and Panagiotis Tzionas
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Democratic University ,Civil Society ,Collapse ,Crisis ,Governance ,Political science - Abstract
Although university’s contribution to the democratic society has been studied adequately, the establishment of its internal democratic institutions has not. Issues of autonomy and accountability exist whereas, today’s Postmodernism introduces further uncertainty. After constructing a framework for measuring democracy within a university using democracy indicators selected from international organizations, we attempt to interrelate these indicators to its democratic characteristics, raising the question: “To what extent could these characteristics be eroded before the university collapses?” Interviews with European academics were conducted and the influence of forces external to the university were studied using the Central European University in Hungary as a case study. The findings show that increased state control undermines institutional autonomy and so does imposing unnecessary restrictions. Protecting democracy and academic freedom, civil rights, and supporting an open society are of paramount importance, otherwise the university collapses. A model that captures such catastrophic state changes is finally proposed.
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- 2022
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7. Physical and Dosimetric Aspects of the Iridium-Knife
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Yiannis Roussakis and Georgios Anagnostopoulos
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iridium knife ,brachytherapy ,dosimetry ,high-dose-rate (HDR) brachytherapy ,stereotactic ablative radiotherapy (SABR) ,stereotactic body radiation therapy (SBRT) ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
The three-dimensional iridium-192 (192Ir) high-dose-rate (HDR) brachytherapy manifests itself as a high-precision, hypofractionated, dose-escalating, minimally invasive method in the armamentarium of contemporary radiation oncology clinical applications. In this study, the physical aspects of the 192Ir radionuclide are presented. Its dosimetric application in HDR brachytherapy for different anatomical sites (prostate, gynecological malignancies, liver, and intrathoracic tumors) as well as the corresponding dosimetric comparison with the stereotactic body radiation therapy (SBRT) techniques based on a representative selection of dosimetric publications is reviewed and illustrated.
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- 2021
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8. The Holistic Perspective of the INCISIVE Project—Artificial Intelligence in Screening Mammography
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Ivan Lazic, Ferran Agullo, Susanna Ausso, Bruno Alves, Caroline Barelle, Josep Ll. Berral, Paschalis Bizopoulos, Oana Bunduc, Ioanna Chouvarda, Didier Dominguez, Dimitrios Filos, Alberto Gutierrez-Torre, Iman Hesso, Nikša Jakovljević, Reem Kayyali, Magdalena Kogut-Czarkowska, Alexandra Kosvyra, Antonios Lalas, Maria Lavdaniti, Tatjana Loncar-Turukalo, Sara Martinez-Alabart, Nassos Michas, Shereen Nabhani-Gebara, Andreas Raptopoulos, Yiannis Roussakis, Evangelia Stalika, Chrysostomos Symvoulidis, Olga Tsave, Konstantinos Votis, and Andreas Charalambous
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medical images ,mammography ,artificial intelligence ,deep learning ,health data sharing ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Finding new ways to cost-effectively facilitate population screening and improve cancer diagnoses at an early stage supported by data-driven AI models provides unprecedented opportunities to reduce cancer related mortality. This work presents the INCISIVE project initiative towards enhancing AI solutions for health imaging by unifying, harmonizing, and securely sharing scattered cancer-related data to ensure large datasets which are critically needed to develop and evaluate trustworthy AI models. The adopted solutions of the INCISIVE project have been outlined in terms of data collection, harmonization, data sharing, and federated data storage in compliance with legal, ethical, and FAIR principles. Experiences and examples feature breast cancer data integration and mammography collection, indicating the current progress, challenges, and future directions.
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- 2022
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9. Assessing the strength of democratic institutions associated with modern universities: the case of the Greek university
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Vaia Papanikolaou, Panagiotis Tzionas, and Yiannis Roussakis
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Organizational Behavior and Human Resource Management ,Higher education ,Management science ,business.industry ,Constitution ,media_common.quotation_subject ,05 social sciences ,050301 education ,Contrast (statistics) ,Democracy ,Field (computer science) ,Education ,Interdependence ,0502 economics and business ,Structured interview ,Sociology ,Adaptation (computer science) ,business ,0503 education ,050203 business & management ,media_common - Abstract
This paper proposes the establishment of a systematic framework for measuring dimensions of democracy within a university. It is shown that certain indicators internationally established and validated for the measurement of the institutional characteristics of democracy can, through appropriate adaptation, be transferred to the university field. A new model of mapping these characteristics to the university field was built using all available knowledge from international surveys, valid databases and researches conducted using questionnaires and structured interviews, specifically for the purposes of this paper. Chord diagrams, capable of providing meaningful dynamic graphical representations, were employed as a novel evaluative tool that highlights the existence and degree of significant interrelations between democracy indicators and democratic characteristics of the university. As a case study, we have chosen to analyze, compare and contrast the three most representative laws governing the operation of Greek universities for the last 35 years using the proposed model. Its operation, validity and capabilities were verified, after encapsulating the complex interdependencies among its variables, for a large time period, influenced by adverse social and economic changes. Thus, it can be used as an effective tool for comparisons among different universities, with respect to their democratic constitution.
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- 2020
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10. Considerations for artificial intelligence clinical impact in oncologic imaging: an AI4HI position paper
- Author
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Luis Marti-Bonmati, Dow-Mu Koh, Katrine Riklund, Maciej Bobowicz, Yiannis Roussakis, Joan C. Vilanova, Jurgen J. Fütterer, Jordi Rimola, Pedro Mallol, Gloria Ribas, Ana Miguel, Manolis Tsiknakis, Karim Lekadir, and Gianna Tsakou
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Artificial intelligence ,All institutes and research themes of the Radboud University Medical Center ,ComputingMethodologies_PATTERNRECOGNITION ,Urological cancers Radboud Institute for Health Sciences [Radboudumc 15] ,Clinical validation ,Radiology, Nuclear Medicine and imaging ,Radiologi och bildbehandling ,Prediction models ,Oncologic imaging ,Radiology, Nuclear Medicine and Medical Imaging - Abstract
To achieve clinical impact in daily oncological practice, emerging AI-based cancer imaging research needs to have clearly defined medical focus, AI methods, and outcomes to be estimated. AI-supported cancer imaging should predict major relevant clinical endpoints, aiming to extract associations and draw inferences in a fair, robust, and trustworthy way. AI-assisted solutions as medical devices, developed using multicenter heterogeneous datasets, should be targeted to have an impact on the clinical care pathway. When designing an AI-based research study in oncologic imaging, ensuring clinical impact in AI solutions requires careful consideration of key aspects, including target population selection, sample size definition, standards, and common data elements utilization, balanced dataset splitting, appropriate validation methodology, adequate ground truth, and careful selection of clinical endpoints. Endpoints may be pathology hallmarks, disease behavior, treatment response, or patient prognosis. Ensuring ethical, safety, and privacy considerations are also mandatory before clinical validation is performed. The Artificial Intelligence for Health Imaging (AI4HI) Clinical Working Group has discussed and present in this paper some indicative Machine Learning (ML) enabled decision-support solutions currently under research in the AI4HI projects, as well as the main considerations and requirements that AI solutions should have from a clinical perspective, which can be adopted into clinical practice. If effectively designed, implemented, and validated, cancer imaging AI-supported tools will have the potential to revolutionize the field of precision medicine in oncology.
- Published
- 2021
11. Measuring Democratization and Detecting State Transitions
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Panagiotis Tzionas, Vaia Papanikolaou, and Yiannis Roussakis
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State Transition ,Computer science ,media_common.quotation_subject ,Democratization ,Multi-objective optimization ,Data science ,Democracy ,Variety (cybernetics) ,Conceptual framework ,Order (exchange) ,Set (psychology) ,Objectivity (science) ,Multi-objective Optimization ,media_common - Abstract
In the proposed research, an in-depth analysis of the features presented in six representative international organizations measuring democracy worldwide revealed a sizeable set of significant and complementary indicators that provided the basis for the construction of a common conceptual framework for democratization. The size and variety of the examined datasets overcomes any possible skepticism for data biasing. We also propose a method of combining such complementary or competing indicators using Multi-objective Optimization, in order to increase objectivity. The periodic monitoring of the proposed indicators allows for the detection of State Transitions, especially under alarming conditions. Our aim is to propose an objective tool for policy makers that would eliminate selective interpretation of democracy and its transitions, by allowing political change to be meaningfully understood in its proper perspective using facts and data.
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- 2020
12. Ethical Decision Making in Emergent Emergencies under a Veil of Ignorance
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Vaia Papanikolaou, Panagiotis Tzionas, and Yiannis Roussakis
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media_common.quotation_subject ,Political Science ,pandemic ,Ethical decision ,Veil of ignorance ,Morality ,ethics ,Disadvantaged ,policy making ,Social inequality ,Psychological resilience ,Element (criminal law) ,Covid-19 ,Normality ,media_common ,Law and economics - Abstract
In this paper we initially propose a scheme for the determination of threats due to the Covid19 pandemic, followed by appropriate response measures. In order to devise successful response actions, one should pay extreme care in identifying the actual threats posed and, as a matter of fact, prioritize them with respect to their severity on human life, societal risks, democratic operation of the institutions and the state and irreversible environmental impact.But would everyone be benefited the same by these response measures? There lies the danger to be unfair of even ignoring socially disadvantaged groups and, thus, increasing social inequality gaps. And the new equilibrium attained runs the danger of being less stable than the old one, exhibiting degraded emergent behavior and capabilities for self-organization. In this case we would have achieved exactly the opposite of what we wished for, a system of lower resilience to perturbations.Thus, we argue that the ethical element is the predominant factor that should determine all types of feedback responses and actions taken by decision-makers in all political, social, economic and environmental aspects during the process of returning to normality.Towards this purpose, a method of determining the morality of response measures is required. A variation of the ‘Veil of Ignorance’ provides such a method, as introduced in this paper. It asks the decision-makers to make choices about social or moral issues related to the feedback responses to the pandemic and assumes that they have enough information to know the consequences of their possible decisions for everyone but would not know which person they will be themselves, in the new equilibrium. We believe that the proposed ethical framework will result to just and fair to all response measures.
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- 2020
13. Education in Social Entrepreneurship for Sustainable Development
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Vasiliki Brinia, Thalia Dragonas, and Yiannis Roussakis
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Sustainable development ,Economic growth ,Social entrepreneurship ,Sociology - Published
- 2020
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14. Contra Aquam Remigare*: Reimagining Humanistic Paideia Through Comparative-Historical Analysis of Education
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Yiannis Roussakis
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Instrumentalism ,media_common.quotation_subject ,05 social sciences ,Paideia ,050301 education ,Humanism ,Social issues ,Education ,Epistemology ,Educational research ,050903 gender studies ,Reading (process) ,Sociology ,0509 other social sciences ,Comparative education ,Philosophy of education ,0503 education ,media_common - Abstract
This article attempts a reading of Andreas M. Kazamias’s work and method as a persistent and firmly grounded attempt to “go against the tide” of an empirical/instrumentalist comparative education a...
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- 2018
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15. Initial Teacher Education in Secondary Education (Greece)
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Yiannis Roussakis
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Secondary education ,Pedagogy ,Sociology ,Teacher education - Published
- 2020
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16. Who Carries the National Flag?: The Politics of Cultural Identity in the Increasingly Multicultural Greek School
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Dimitris Theocharis, Dimitrios Mattheou, and Yiannis Roussakis
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Cultural identity ,business.industry ,media_common.quotation_subject ,Multicultural education ,Social change ,Gender studies ,Public opinion ,Education ,Nationalism ,Multiculturalism ,Political science ,Social science ,business ,Cultural pluralism ,Flag (geometry) ,media_common - Published
- 2005
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17. Crisis and Reform in Greek Education
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Yiannis Roussakis and Andreas M. Kazamias
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International education ,Law ,Sociology ,Comparative education ,Education - Abstract
Andreas Kazamias is professor of comparative education at the University of Madison, Wisconsin, and professor emeritus at the University of Athens. He was a founding member of the Comparative and International Education Society of North America (CIES). He is a member of the Athens Academy and a honorary fellow of the Comparative and International Education Society.
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- 2003
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18. Real-time Cherenkov emission portal imaging during CyberKnife® radiotherapy.
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Yiannis Roussakis, Rongxiao Zhang, Geoff Heyes, Gareth Webster, Suzannah Mason, Stuart Green, Brian Pogue, and Hamid Dehghani
- Subjects
- *
CHERENKOV radiation , *RADIOTHERAPY , *LINEAR accelerators , *RADIOSURGERY , *DIAGNOSTIC imaging - Abstract
The feasibility of real-time portal imaging during radiation therapy, through the Cherenkov emission (CE) effect is investigated via a medical linear accelerator (CyberKnife®) irradiating a partially-filled water tank with a 60 mm circular beam. A graticule of lead/plywood and a number of tissue equivalent materials were alternatively placed at the beam entrance face while the induced CE at the exit face was imaged using a gated electron-multiplying-intensified-charged-coupled device (emICCD) for both stationary and dynamic scenarios. This was replicated on an Elekta Synergy® linear accelerator with portal images acquired using the iViewGT™ system. Profiles across the acquired portal images were analysed to reveal the potential resolution and contrast limits of this novel CE based portal imaging technique and compared against the current standard. The CE resolution study revealed that using the lead/plywood graticule, separations down to 3.4 ± 0.5 mm can be resolved. A 28 mm thick tissue-equivalent rod with electron density of 1.69 relative to water demonstrated a CE contrast of 15% through air and 14% through water sections, as compared to a corresponding contrast of 19% and 12% using the iViewGT™ system. For dynamic scenarios, video rate imaging with 30 frames per second was achieved. It is demonstrated that CE-based portal imaging is feasible to identify both stationary and dynamic objects within a CyberKnife® radiotherapy treatment field. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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