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EUROPEAN JOURNAL OF PHYSICS 2015年第3期36卷

作者： Cheng, Carmen Guy, Matthew Narduzzo, Alessandro Takashina, Kei Univ Bath Dept Phys Bath BA2 7AY Avon England

Recent research into applications of the Leidenfrost effect have sparked renewed interest for this phenomenon. We report here on some of these developments, and on their deployment in an undergraduate teaching project that culminated in the production of a viral internet video. We analyse the key ingredients to the project's apparent success, both in terms of physics pedagogy and outreach/public engagement.

关键词： outreach public engagement Leidenfrost demonstration experiments and apparatus learning theory and science teaching multiphase flows

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MO-A-BRB-01: TG191: Clinical Use of Luminescent Dosimeters

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Medical Physics 2016年第6PART28期43卷 3690-3690页

作者： S. Kry UT MD Anderson Cancer Center

This presentation will highlight the upcoming TG-191 report: Clinical Use of Luminescent Dosimeters. Luminescent dosimetry based on TLD and OSLD is a practical, accurate, and precise technique for point dosimetry in medical physics applications. The charges of Task Group 191 were to detail the methodologies for practical and optimal luminescent dosimetry in a clinical setting. This includes (1) To review the variety of TLD/OSL materials available, including features and limitations of each. (2) To outline the optimal steps to achieve accurate and precise dosimetry with luminescent detectors and to evaluate the uncertainty induced when less rigorous procedures are used. (3) To develop consensus guidelines on the optimal use of luminescent dosimeters for clinical practice. (4) To develop guidelines for special medically relevant uses of TLDs/OSLs (e.g., mixed field i.e. photon/neutron dosimetry, particle beam dosimetry, skin dosimetry). While this report provides general guidelines for arbitrary TLD and OSLD processes, the report, and therefore this presentation, provide specific guidance for TLD-100 (LiF:Ti,Mg) and nanoDot (Al2O3:C) dosimeters because of their prevalence in clinical practice. learning Objectives: 1. Understand the available dosimetry systems, and basic theory of their operation 2. Understand the range of dose determination methodologies and the uncertainties associated with them 3. Become familiar with special considerations for TLD/OSLD relevant for special clinical situations 4. Learn recommended commissioning and QA procedures for these dosimetry systems.

关键词： Dosimetry Thermoluminescent dosimeters Particle beam detectors learning theory and science teaching Nanodots Luminescent materials Systems analysis

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MO-A-BRB-00: TG191: Clinical Use of Luminescent Dosimeters

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Medical Physics 2016年第6PART28期43卷 3690-3690页

作者： Stephen Kry Moderator UT MD Anderson Cancer Center Houston TX

关键词： Dosimetry Thermoluminescent dosimeters Particle beam detectors Luminescent materials Systems analysis Nanodots learning theory and science teaching

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WE-AB-BRA-03: Non-Invasive Controlled Release from Implantable Hydrogel Scaffolds Using Ultrasound

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Medical Physics 2016年第6PART38期43卷 3791-3791页

作者： A Moncion O.D Kripfgans A.J Putnam R.T Frances chi M.L Fabiilli University of Michigan Ann Arbor MI

Purpose: To control release of a model payload in acoustically responsive scaffolds (ARSs) using focused ultrasound (FUS). Methods: Fluorescently-labeled dextran (10 kDa) was encapsulated in sonosensitive perfluorocarbon (C 6 F 14 or C 5 F 12 ) double emulsions (mean diameter: 2.9±0.1 µm). For in vitro release studies, 0.5 mL ARSs (10 mg/mL fibrin, 1% (v/v) emulsion) were polymerized in 24 well plates and covered with 0.5 mL medium. Starting one day after polymerization, ARSs were exposed to FUS (2.5 MHz, Pr = 8 MPa, 13 cycles, 100 Hz PRF) for 2 min daily. The amount of dextran released into the media was quantified. For in vivo studies, 0.25 mL ARSs were prepared as described previously and injected subcutaneously in the lower back of BALB/c mice. After polymerization, a subset of the implanted ARSs were exposed to FUS (as previously described). Animals were imaged longitudinally using a fluorescence imaging system to quantify the amount of dextran released from the ARSs. Results: In vitro: Over 6 days, +FUS displayed an 8.2-fold increase in dextran release compared to −FUS (−FUS: 2.7±0.6%; +FUS: 22.2±3.0%) for C 6 F 14 ARSs, and a 6.7-fold increase (−FUS: 5.0±0.8%; +FUS: 38.5±1.6%) for C 5 F 12 :C 6 F 14 ARSs. In vivo: +FUS displayed statistically greater dextran release compared to −FUS one day after implantation for C 5 F 12 :C 6 F 14 ARSs (−FUS: 55.1±1.5%; +FUS: 74.1±2.2%) and three days after implantation for C 6 F 14 ARSs (−FUS: 1.4±6.5%; +FUS: 30.4±5.4%). Conclusion: FUS enables non-invasive control of payload release from an ARS, which could benefit growth factor delivery for tissue regeneration. ARS are versatile due to their tunability (i.e. stiffness, emulsion composition, FUS pressure, FUS frequency, etc.) and can be modified to for optimal payload release. Future work will optimize ARS formulations for in vivo use to minimize payload release in the absence of FUS. This work was supported by NIH Grant R21 AR065010 (M.L. Fabiilli) and the Basic Radiologi

关键词： Emulsions Ultrasonography Polymerization Acoustic modeling Fluorescence learning theory and science teaching Gels Awards Tissues

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SU-F-E-08: Medical Physics as a teaching Tool for High School science Curriculum

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Medical Physics 2016年第6PART5期43卷 3354-3354页

作者： L Buckley The Ottawa Hospital Cancer Ctr. Ottawa ON

Purpose: Delivering high school science curriculum in a timely manner and in way that is accessible to all students is a challenge for teachers. Although many high schools offer career workshops, these are typically directed at senior students and do not relate directly to details of the curriculum. The objective of this initiative was to create a series of lectures that use medical physics to relate many aspects of the high school science curriculum to tangible clinical applications and to introduce students to alternate pathways into a career in health sciences. Methods: A series of lectures has been developed based on the Ontario High School science Curriculum. Each lecture uses a career in radiotherapy medical physics as the framework for discussion of topics specific to the high school course being addressed. Results: At present, these lectures have been delivered in five area high schools to students ranging from sophomores to seniors. Survey documents are given to the students before and after the lecture to assess their awareness of careers in health care, applications of physics and their general interest in the subject areas. As expected, students have limited up front awareness of the wide variety of health related career paths. The idea of combining a career lecture with topics specific to the classroom curriculum has been well-received by teachers and students alike. Conclusion: Career talks for high school students are useful for students contemplating their post- secondary career path. Relating career discussion with direct course curriculum makes their studies more relevant and engaging. Students aspiring to a career in health sciences often focus their studies on life sciences due to limited knowledge of potential careers. An early introduction to medical physics presents them with an alternate path through the physical sciences into health care.

关键词： K-12 education Lectures learning theory and science teaching Radiation therapy

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In Memoriam of Bengt Bjarngard: SBRT II: Small Field Dosimetry-TG155

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MEDICAL PHYSICS 2014年第6期41卷 418-419页

作者： Das, I. Reft, C. Indiana Univ Sch Med Indianapolis IN 46202 USA Univ Chicago Chicago IL 60637 USA

Specialized radiation treatment such as SRS/SRT. SBRT, IMRT, VMAT, Tomotherapy, CyberKnife and Gamma Knife use small fields or combination of small fields where dosimetry is challenging and uncertain due to non-equilibrium conditions such as longitudinal and lateral disequilibrium. Additionally the primary photon fluence is greatly affected by the obstruction of the source size by the jaws creating a large dose gradient across the field. Electronic equilibrium is a phenomenon associated with the range of secondary particles which depend on the beam energy, photon spectrum and the composition of the medium. Additionally, the finite size of detectors creates volume averaging and fluence perturbations especially in small fields. The IAEA/AAPM has provided a frame work for non-compliant reference dosimetry in small fields1. The AAPM TG-1552 has adopted this frame work to provide guidelines in relative dosimetry. This course provides the insight of TG-155 that defines small field, provides recommendations for suitable detectors and associated correction factors to convert reading to dose. Recommendations of a good working practice for relative dosimetry measurements (PDD, TMR, output factor, etc.) and dose calculations based on the new formulation is are elaborated. It also discusses beam modeling and dose calculations as a critical step in clinical utilization of small field radiotherapy. Small errors in beam data, approximations in dose algorithms, or misaligned of detectors and field settings can propagate into large errors in planned and delivered dose. The modeling and treatment planning aspects of small field dosimetry are reviewed with emphasis on the most critical parts for ensuring accurate and safe radiation therapy. Discussion on k(fmsr, fclin) for commercially available detectors are also provided.1 P. Alfonso, P. Andreo, R. Capote, M. S. Huq, W. Kilby, P. Kjall, T. R. Mackie, H. Palmans, K. Rosser, J. Seuntjens, W. Ullrich and S. Vatnitsky, “A new formalism

关键词： Dosimetry Photons Particle beam detectors learning theory and science teaching Radiation treatment Intensity modulated radiation therapy Radiosurgery Medical treatment planning

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WE-E-BRB-00: Knowledge-Based Treatment Planning Automation

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Medical Physics 2015年第6PART39期42卷 3674-3674页

作者： Xiaodong Zhang Moderator UT MD Anderson Cancer Center Houston TX

The knowledge-based treatment planning automation has evolved from academic research from the clinical application with the involvement of the major industry TPS vendors. Previous work proved the concept that IMRT or VMAT plans can be designed without or with minimal human intervention. Recently, the major industry vendors start releasing the automatic planning product such as Philips automatic treatment planning, Varian's Rapidplan, and RaySearch's autoplan. Many centers start to evaluate and use the automatic planning products from TPS vendors. It is more and more becoming evident that automatic planning will be routinely used in the clinic. The first presentation will focus on the knowledge modeling for clinical treatment planning. The presenter will introduce the algorithm and theory for developing the dose volume histogram (DVH) model, summarize the results on the validation of the DVH model, and discuss the application of DVH for the automatic treatment planning. The second presenter will focus on the clinical use of the automatic treatment planning. The presenter will give an overview of the several automatic treatment planning tools including the tools developed commercially and in-house, present the early experience of using those tools, and discuss the application of the tools in the routine clinical use and in the quality control of the treatment planning. learning Objectives: 1. Describe the algorithm and theory behind the knowledge based treatment planning automation. 2. Clinical experience of using automatic planning in clinical trial and patient treatment 3. Early clinical experience of using commercial automatic planning approach 4. The application of automatic planning approach to perform quality assurance of treatment plan. XD obtain the research funding from Varian Medical System, Philips Medical System and Funding support form Sister Institution Network Fund of MD Anderson, XD is also a founder of Global Oncology One

关键词： Medical treatment planning science funding Quality assurance Intensity modulated radiation therapy learning theory and science teaching Cancer

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WE-E-BRB-01: Clinical Usage of Knowledge Based Treatment Planning

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Medical Physics 2015年第6PART39期42卷 3674-3674页

作者： X. Zhang UT MD Anderson Cancer Center

关键词： Medical treatment planning science funding Quality assurance learning theory and science teaching Cancer Intensity modulated radiation therapy

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WE-E-BRB-02: Knowledge Modeling For Clinical Treatment Planning

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Medical Physics 2015年第6PART39期42卷 3674-3674页

作者： Q. Wu Duke University Medical Center

关键词： Medical treatment planning science funding Quality assurance Intensity modulated radiation therapy Cancer learning theory and science teaching

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MO-E-18C-04: Advanced Computer Simulation and Visualization Tools for Enhanced Understanding of Core Medical Physics Concepts

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Medical Physics 2014年第6PART25期41卷 427-427页

作者： S Naqvi Saint Agnes Cancer Institute Department of Radiation Oncology Baltimore MD

Purpose: Most medical physics programs emphasize proficiency in routine clinical calculations and QA. The formulaic aspect of these calculations and prescriptive nature of measurement protocols obviate the need to frequently apply basic physical principles, which, therefore, gradually decay away from memory. E.g. few students appreciate the role of electron transport in photon dose, making it difficult to understand key concepts such as dose buildup, electronic disequilibrium effects and Bragg-Gray theory. These conceptual deficiencies manifest when the physicist encounters a new system, requiring knowledge beyond routine activities. Methods: Two interactive computer simulation tools are developed to facilitate deeper learning of physical principles. One is a Monte Carlo code written with a strong educational aspect. The code can “label” regions and interactions to highlight specific aspects of the physics, e.g., certain regions can be designated as “starters” or “crossers,” and any interaction type can be turned on and off. Full 3D tracks with specific portions highlighted further enhance the visualization of radiation transport problems. The second code calculates and displays trajectories of a collection electrons under arbitrary space/time dependent Lorentz force using relativistic kinematics. Results: Using the Monte Carlo code, the student can interactively study photon and electron transport through visualization of dose components, particle tracks, and interaction types. The code can, for instance, be used to study kerma-dose relationship, explore electronic disequilibrium near interfaces, or visualize kernels by using interaction forcing. The electromagnetic simulator enables the student to explore accelerating mechanisms and particle optics in devices such as cyclotrons and linacs. Conclusion: The proposed tools are designed to enhance understanding of abstract concepts by highlighting various aspects of the physics. The simulations serve as virtual experi

关键词： Electronic transport Electromagnetic optics Photons Medical physics Computer simulation Lorentz group learning theory and science teaching learning Kinematics Physicists

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