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DOE OSTI2015

WE-AB-213-04: IAEA Support to Medical Physics in Africa and Latin America: Achievements and Challenges

AAPM projects and collaborations in Africa Adam Shulman (AA-SC Chair) The African Affairs Subcommittee (AA-SC) of the AAPM will present a multi-institutional approach to medical physics support in Africa. Current work to increase the quality of care and level of safety for the medical physics practice in Senegal, Ghana, and Zimbabwe will be presented, along with preliminary projects in Nigeria and Botswana. Because the task of addressing the needs of medical physics in countries across Africa is larger than one entity can accomplish on its own, the AA-SC has taken the approach of joining forces with multiple organizations such as Radiating Hope and TreatSafely (NGO’s), the IAEA, companies like BrainLab, Varian and Elekta, medical volunteers and academic institutions such as NYU and Washington University. Elements of current projects include: 1) Distance training and evaluation of the quality of contouring and treatment planning, teaching treatment planning and other subjects, and troubleshooting using modern telecommunications technology in Senegal, Ghana, and Zimbabwe; 2) Assistance in the transition from 2D to 3D in Senegal and Zimbabwe; 3) Assistance in the transition from 3D to IMRT using in-house compensators in Senegal; 4) Modernizing the cancer center in Senegal and increasing safety and; 5) Training on on 3D techniques in Ghana; 6) Assisting a teaching and training radiation oncology center to be built in Zimbabwe; 7) Working with the ISEP Program in Sub-Saharan Africa; 8) Creating instructional videos on linac commissioning; 9) Working on a possible collaboration to train physicists in Nigeria. Building on past achievements, the subcommittee seeks to make a larger impact on the continent, as the number and size of projects increases and more human resources become available. The State of Medical Physics Collaborations and Projects in Latin America Sandra Guzman (Peru) The lack of Medical Physicists (MP) in many Latin American (LA) countries leads to recruitment of professionals with incomplete education. In most LA countries only one MP responsible for each Center is currently mandated. Currently there is a large disparity among MP training programs and there is significant debate about the standards of MP graduate education in many LA countries. There are no commonly recognized academic programs, not enough clinical training sites and clinical training is not typically considered as part of the MP work. Economic pressures and high workloads also impede the creation of more training centers. The increasing need of qualified MPs require establishing a coordinated system of national Education & Training Centers (ETC), to meet the international standards of education and training in Medical Physics. This shortfall calls for support of organizations such as the IOMP, AAPM, ALFIM, IAEA, etc. Examples from various LA countries, as well as some proposed solutions, will be presented. In particular, we will discuss the resources that the AAPM and its members can offer to support regional programs. The ‘Medical Imaging’ physicist in the emerging world: Challenges and opportunities - Caridad Borrás (WGNIMP Chair) While the role of radiation therapy physicists in the emerging world is reasonably well established, the role of medical imaging physicists is not. The only perceived needs in radiology departments are equipment quality control and radiation protection, tasks that can be done by a technologist or a service engineer. To change the situation, the International Basic Safety Standard, which is adopted/adapted world-wide as national radiation protection regulations, states: “For diagnostic radiological procedures and image guided interventional procedures, the requirements of these Standards for medical imaging, calibration, dosimetry and quality assurance, including the acceptance and commissioning of medical radiological equipment, are fulfilled by or under the oversight of, or with the documented advice of a medical physicist, whose degree of involvement is determined by the complexity of the radiological procedures and the associated radiation risks”. Details on how these requirements can be carried out in resource-limited settings will be described. IAEA support to medical physics in Africa and Latin America: achievements and challenges Ahmed Meghzifene (IAEA) Shortage of clinically qualified medical physicists in radiotherapy and imaging, insufficient and inadequate education and training programs, as well as a lack of professional recognition were identified as the main issues to be addressed by the IAEA. The IAEA developed a series of integrated projects aiming specifically at promoting the essential role of medical physicists in health care, developing harmonized guidelines on dosimetry and quality assurance, and supporting education and clinical training programs. The unique feature of the IAEA approach is support it provides for implementation of guidelines and education programs in Member States through its technical cooperation project. The presentation will summarize IAEA support to Latin America and Africa in the field of medical physics and will highlight how the new International Basic Safety Standards are expected to impact the medical physics practice in low and middle income countries. Learning Objectives: Learn about the shortage of qualified Medical Physicists in Africa and Latin America. Understand the reasons of this shortage. Learn about the ways to improve the situation and AAPM role in this process.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

WE-AB-213-05: Closing Remarks

AAPM projects and collaborations in Africa Adam Shulman (AA-SC Chair) The African Affairs Subcommittee (AA-SC) of the AAPM will present a multi-institutional approach to medical physics support in Africa. Current work to increase the quality of care and level of safety for the medical physics practice in Senegal, Ghana, and Zimbabwe will be presented, along with preliminary projects in Nigeria and Botswana. Because the task of addressing the needs of medical physics in countries across Africa is larger than one entity can accomplish on its own, the AA-SC has taken the approach of joining forces with multiple organizations such as Radiating Hope and TreatSafely (NGO’s), the IAEA, companies like BrainLab, Varian and Elekta, medical volunteers and academic institutions such as NYU and Washington University. Elements of current projects include: 1) Distance training and evaluation of the quality of contouring and treatment planning, teaching treatment planning and other subjects, and troubleshooting using modern telecommunications technology in Senegal, Ghana, and Zimbabwe; 2) Assistance in the transition from 2D to 3D in Senegal and Zimbabwe; 3) Assistance in the transition from 3D to IMRT using in-house compensators in Senegal; 4) Modernizing the cancer center in Senegal and increasing safety and; 5) Training on on 3D techniques in Ghana; 6) Assisting a teaching and training radiation oncology center to be built in Zimbabwe; 7) Working with the ISEP Program in Sub-Saharan Africa; 8) Creating instructional videos on linac commissioning; 9) Working on a possible collaboration to train physicists in Nigeria. Building on past achievements, the subcommittee seeks to make a larger impact on the continent, as the number and size of projects increases and more human resources become available. The State of Medical Physics Collaborations and Projects in Latin America Sandra Guzman (Peru) The lack of Medical Physicists (MP) in many Latin American (LA) countries leads to recruitment of professionals with incomplete education. In most LA countries only one MP responsible for each Center is currently mandated. Currently there is a large disparity among MP training programs and there is significant debate about the standards of MP graduate education in many LA countries. There are no commonly recognized academic programs, not enough clinical training sites and clinical training is not typically considered as part of the MP work. Economic pressures and high workloads also impede the creation of more training centers. The increasing need of qualified MPs require establishing a coordinated system of national Education & Training Centers (ETC), to meet the international standards of education and training in Medical Physics. This shortfall calls for support of organizations such as the IOMP, AAPM, ALFIM, IAEA, etc. Examples from various LA countries, as well as some proposed solutions, will be presented. In particular, we will discuss the resources that the AAPM and its members can offer to support regional programs. The ‘Medical Imaging’ physicist in the emerging world: Challenges and opportunities - Caridad Borrás (WGNIMP Chair) While the role of radiation therapy physicists in the emerging world is reasonably well established, the role of medical imaging physicists is not. The only perceived needs in radiology departments are equipment quality control and radiation protection, tasks that can be done by a technologist or a service engineer. To change the situation, the International Basic Safety Standard, which is adopted/adapted world-wide as national radiation protection regulations, states: “For diagnostic radiological procedures and image guided interventional procedures, the requirements of these Standards for medical imaging, calibration, dosimetry and quality assurance, including the acceptance and commissioning of medical radiological equipment, are fulfilled by or under the oversight of, or with the documented advice of a medical physicist, whose degree of involvement is determined by the complexity of the radiological procedures and the associated radiation risks”. Details on how these requirements can be carried out in resource-limited settings will be described. IAEA support to medical physics in Africa and Latin America: achievements and challenges Ahmed Meghzifene (IAEA) Shortage of clinically qualified medical physicists in radiotherapy and imaging, insufficient and inadequate education and training programs, as well as a lack of professional recognition were identified as the main issues to be addressed by the IAEA. The IAEA developed a series of integrated projects aiming specifically at promoting the essential role of medical physicists in health care, developing harmonized guidelines on dosimetry and quality assurance, and supporting education and clinical training programs. The unique feature of the IAEA approach is support it provides for implementation of guidelines and education programs in Member States through its technical cooperation project. The presentation will summarize IAEA support to Latin America and Africa in the field of medical physics and will highlight how the new International Basic Safety Standards are expected to impact the medical physics practice in low and middle income countries. Learning Objectives: Learn about the shortage of qualified Medical Physicists in Africa and Latin America. Understand the reasons of this shortage. Learn about the ways to improve the situation and AAPM role in this process.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Theoretical Model for Volume Fraction of UC, 235U Enrichment, and Effective Density of Final U 10Mo Alloy

The purpose of this document is to provide a theoretical framework for (1) estimating uranium carbide (UC) volume fraction in a final alloy of uranium with 10 weight percent molybdenum (U-10Mo) as a function of final alloy carbon concentration, and (2) estimating effective 235 U enrichment in the U-10Mo matrix after accounting for loss of 235 U in forming UC. This report will also serve as a theoretical baseline for effective density of as-cast low-enriched U-10Mo alloy. Therefore, this report will serve as the baseline for quality control of final alloy carbon content

36 MATERIALS SCIENCE↗
DOE OSTI2024

ARJUNA: An Electrochemical Interface Mapping Probe for Solid-State Batteries

Solid-state batteries (SSBs) are promising candidates for next-generation energy storage, although their performance can be compromised by interfacial heterogeneity within the electrolyte. Furthermore, ensuring the quality of large form-factors electrolyte film is crucial for establishing a robust manufacturing platform for solid-state batteries. Herein, we report on the use of ARJUNA, an electrochemical interface mapping system, to characterize heterogeneities at solid electrolyte interfaces and to serve as a quality control system for SSB manufacturing. In addition to spatial mapping, the proposed system can also probe the interface behavior as a function of pressure and temperature. We present the operating principle, design, instrumentation, and evaluation of the system alongside a typical hybrid solid electrolyte produced using two common manufacturing processes. This report showcases the capability of ARJUNA to probe the heterogeneity and quality of processed solid electrolyte films.

25 ENERGY STORAGE↗
DOE OSTI2016

Characterisation of imperial college reactor centre legacy waste using gamma-ray spectrometry

Waste characterisation is a principal component in waste management strategy. The characterisation includes identification of chemical, physical and radiochemical parameters of radioactive waste. Failure to determine specific waste properties may result in sentencing waste packages which are not compliant with the regulation of long term storage or disposal. This project involved measurement of intensity and energy of gamma photons which may be emitted by radioactive waste generated during decommissioning of Imperial College Reactor Centre (ICRC). The measurement will use High Purity Germanium (HPGe) as Gamma-ray detector and ISOTOPIC-32 V4.1 as analyser. In order to ensure the measurements provide reliable results, two quality control (QC) measurements using difference matrices have been conducted. The results from QC measurements were used to determine the accuracy of the ISOTOPIC software.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2015

Development of realistic physical breast phantoms matched to virtual breast phantoms based on human subject data

Purpose: Physical phantoms are essential for the development, optimization, and evaluation of x-ray breast imaging systems. Recognizing the major effect of anatomy on image quality and clinical performance, such phantoms should ideally reflect the three-dimensional structure of the human breast. Currently, there is no commercially available three-dimensional physical breast phantom that is anthropomorphic. The authors present the development of a new suite of physical breast phantoms based on human data. Methods: The phantoms were designed to match the extended cardiac-torso virtual breast phantoms that were based on dedicated breast computed tomography images of human subjects. The phantoms were fabricated by high-resolution multimaterial additive manufacturing (3D printing) technology. The glandular equivalency of the photopolymer materials was measured relative to breast tissue-equivalent plastic materials. Based on the current state-of-the-art in the technology and available materials, two variations were fabricated. The first was a dual-material phantom, the Doublet. Fibroglandular tissue and skin were represented by the most radiographically dense material available; adipose tissue was represented by the least radiographically dense material. The second variation, the Singlet, was fabricated with a single material to represent fibroglandular tissue and skin. It was subsequently filled with adipose-equivalent materials including oil, beeswax, and permanent urethane-based polymer. Simulated microcalcification clusters were further included in the phantoms via crushed eggshells. The phantoms were imaged and characterized visually and quantitatively. Results: The mammographic projections and tomosynthesis reconstructed images of the fabricated phantoms yielded realistic breast background. The mammograms of the phantoms demonstrated close correlation with simulated mammographic projection images of the corresponding virtual phantoms. Furthermore, power-law descriptions of the phantom images were in general agreement with real human images. The Singlet approach offered more realistic contrast as compared to the Doublet approach, but at the expense of air bubbles and air pockets that formed during the filling process. Conclusions: The presented physical breast phantoms and their matching virtual breast phantoms offer realistic breast anatomy, patient variability, and ease of use, making them a potential candidate for performing both system quality control testing and virtual clinical trials.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2022

In-Line Membrane Thickness Mapping with Real-Time Data Processing

The goal of this project is commercialization of a novel, patented by NREL, non-contact, in-line quality control thickness mapping tool that will enable 100% area inspection of multilayer polymer film assemblies, such as a PEM on a casting substrate, during continuous high-volume R2R manufacturing.

ENGINEERING,HYDROGEN↗
DOE OSTI2015

SU-E-T-643: Pure Alanine Dosimeter for Verification Dosimetry in IMRT

Purpose: The objective of this study was evaluation of accuracy of pure alanine dosimeters measuring intensity-modulated radiation therapy (IMRT) dose distributions in a thorax phantom. Methods: Alanine dosimeters were prepared in the form of 110 mg pure L-α-alanine powder filled into clear tissue-equivalent polymethylmethacrylate (PMMA) plastic tubes with the dimensions 25 mm length, 3 mm inner diameter, and 1 mm wall thickness. A dose-response calibration curve was established for the alanine by placing the dosimeters at 1.5 cm depth in a 30×30×30 cm{sup 3} solid water phantom and then irradiating on a linac with 6 MV photon beam at 10×10 cm{sup 2} field size to doses ranging from 1 to 5 Gy. Electron paramagnetic resonance (EPR) spectroscopy was used to determine the absorbed dose in alanine. An IMRT treatment plan was designed for a commercial heterogeneous CIRS thorax phantom and the dose values were calculated at three different points located in tissue, lung, and bone equivalent materials. A set of dose measurements was carried out to compare measured and calculated dose values by placing the alanine dosimeters at those selected locations inside the thorax phantom and delivering the IMRT to the phantom. Results: The alanine dose measurements and the IMRT plan dose calculations were found to be in agreement within ±2%. Specifically, the deviations were −0.5%, 1.3%, and −1.7% for tissue, lung, and bone; respectively. The slightly large deviations observed for lung and bone may be attributed to tissue inhomogeneity, steep dose gradients in these regions, and uncontrollable changes in spectrometer conditions. Conclusion: The results described herein confirmed that pure alanine dosimeter was suitable for in-phantom dosimetry of IMRT beams because of its high sensitivity and acceptable accuracy. This makes the dosimeter a promising option for quality control of the therapeutic beams, complementing the commonly used ionization chambers, TLDs, and films.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2014

TH-A-18A-01: Innovation in Clinical Breast Imaging

Several novel modalities have been or are on the verge of being introduced into the breast imaging clinic. These include tomosynthesis imaging, dedicated breast CT, contrast-enhanced digital mammography, and automated breast ultrasound, all of which are covered in this course. Tomosynthesis and dedicated breast CT address the problem of tissue superimposition that limits mammography screening performance, by improved or full resolution of the 3D breast morphology. Contrast-enhanced digital mammography provides functional information that allows for visualization of tumor angiogenesis. 3D breast ultrasound has high sensitivity for tumor detection in dense breasts, but the imaging exam was traditionally performed by radiologists. In automated breast ultrasound, the scan is performed in an automated fashion, making for a more practical imaging tool, that is now used as an adjunct to digital mammography in breast cancer screening. This course will provide medical physicists with an in-depth understanding of the imaging physics of each of these four novel imaging techniques, as well as the rationale and implementation of QC procedures. Further, basic clinical applications and work flow issues will be discussed. Learning Objectives: To be able to describe the underlying physical and physiological principles of each imaging technique, and to understand the corresponding imaging acquisition process. To be able to describe the critical system components and their performance requirements. To understand the rationale and implementation of quality control procedures, as well as regulatory requirements for systems with FDA approval. To learn about clinical applications and understand risks and benefits/strength and weakness of each modality in terms of clinical breast imaging.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

Sci—Fri PM: Topics — 03: The Global Task Force on Radiotherapy for Cancer Control: Core Investments

The Union for International Cancer Control (UICC) is a membership-based, non-governmental organization with a mandate to “…to unite the cancer community to reduce the global cancer burden, to promote greater equity, and to integrate cancer control into the world health and development agenda.” COMP is an associate member of the UICC. It is well recognized by the UICC that there are major gaps between high, and low and middle income countries, in terms of access to cancer services including access to radiation therapy. In this context, the UICC has developed a Global Task Force on Radiotherapy for Cancer Control with a charge to answer a single question: “What does it cost to close the gap between what exists today and reasonable access to radiotherapy globally?” The Task Force consists of leaders internationally recognized for their radiation treatment related expertise (radiation oncologists, medical physicists, radiation therapists) as well as those with global health and economics specialization. The Task Force has developed three working groups: (1) to look at the global burden of cancer; (2) to look at the infrastructure requirements (facilities, equipment, personnel); and (3) to consider outcomes in terms of numbers of lives saved and palliated patients. A report is due at the World Cancer Congress in December 2014. This presentation reviews the infrastructure considerations under analysis by the second work group. The infrastructure parameters being addressed include capital costs of buildings and equipment and operating costs, which include human resources, equipment servicing and quality control, and general overhead.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2019

How to detect and correct myocardial creep in myocardial perfusion imaging using Rubidium-82 PET?

Reliability of myocardial blood flow (MBF) quantification in myocardial perfusion imaging (MPI) using PET can majorly be affected by the occurrence of myocardial creep when using pharmacologically induced stress. In this paper, we provide instructions on how to detect and correct for myocardial creep. For example, in each time frame of the PET images the myocardium contour and the observed activity have to be compared to check for misalignments. In addition, we provide an overview of the functionality of commonly used software packages to perform this quality control step as not all software packages currently provide this functionality. Furthermore, important clinical considerations to obtain accurate MBF measurements are given.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2015

New synthetic peptide with efficacy for heparin reversal and low toxicity and immunogenicity in comparison to protamine sulfate

Protamine sulfate (PS), the only clinically approved antidote to unfractionated heparin (UFH), is widely used for cardiopulmonary surgery or other extracorporeal circulation situations. However, the applications of PS have accompanied various severe side-effects. In this study, we presented a novel synthesized peptide compound (RRRRR-RRRRR-RRRRR-sulfate, R15S) served as a safer UFH antidote. Comparison studies were conducted between PS and R15S on efficacy and safety, aided by heparin neutralization studies, drug toxicity studies and anaphylactic analysis. Our research demonstrated that R15S contained comparable UFH neutralization activity in vitro and in rats in vivo as to active partial thromboplastin time (APTT) and anti-FXa assays. There was no cytotoxicity for R15S at 60 μg mg{sup −1} or below and the median lethal dose (LD{sub 50}) of R15S in mice was 35.4 mg kg{sup −1}, both of which were similar to that of PS. Furthermore, R15S exhibited no immunogenicity while it was obvious in guinea pigs immunized with PS. The level of cross-reactivity to anti-PS antibodies of R15S was about 30%. Both of which indicated much safer properties of R15S than PS. In conclusion, we presented a promising candidate R15S for UFH reversal, which is effective in neutralizing UFH and potentially safer in use. - Highlights: • R15 sulfate has a comparable unfractionated heparin neutralization activity to PS. • R15 sulfate avoided severe anaphylactic responses which happened to PS in clinical use. • R15 sulfate could provide a stricter quality control compared to PS which may vary with different batches.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

SU-B-BRF-01: Professional Council Symposium: The Evolving US Healthcare Delivery Model, How Will the Medical Physics Profession Be Impacted and How Should We Respond?

The United States' healthcare delivery model is undergoing significant change. Insurance and reimbursement models are rapidly evolving, federal allocations are shifting from specialty services to preventive and generalpractice services, and Accountable Care Organizations are gaining in prominence. One area of focus is on the perceived over-utilization of expensive services such as advanced imaging and, in some cases, radiation therapy. Reimbursement incentives are increasingly aimed at quality metrics, leading to an increased interest in the core concepts of High Reliability Organizations. With the shift in federal resources away from specialty services and the increasing prominence of Accountable Care Organizations, we will likely be challenged to re-assess our traditional model for delivering medical physics services. Medical physicists have a unique combination of education and training in physics principles, radiation physics applications in medicine, human anatomy, as well as safety analysis and quality control methods. An effective medical physicist recognizes that to advance the institution's mission, the medical physicist must join other professional leaders within the institution to provide clear direction and perspective for the entire team. To do that, we must first recognize the macro changes in our healthcare delivery system and candidly assess how the medical physics practice model can evolve in a prudent way to support the institution's objectives while maintaining the traditionally high level of quality and safety. This year's Professional Council Symposium will explore the many facets of the changing healthcare system and its potential impact on medical physics. Dr. Shine will provide an overview of the developing healthcare delivery and reimbursement models, with a focus on how the physician community has adapted to the changing objectives. Mr. White will describe recent changes in the reimbursement patterns for both imaging and radiation therapy services, the underlying imperatives that will influence additional changes in the near-term future, and the broader changes in the medical physics workforce that may arise due to many (often conflicting) directives and incentives both internal and external to the profession. Maintaining the integrity of the medical physics profession and the high quality of medical physics services will require a shared understanding of the changing practice environment and a firm commitment to protecting the key priorities of clinical medical physics as the healthcare system transitions to a new and very different model. To be effective as medical physicists, we must learn how to provide leadership in our respective institutions. Learning Objectives: Understand the macro changes occurring in the US healthcare delivery system. Understand the likely near-term, and possible longer-term, impact on the medical physics profession. Understand some strategies for providing leadership during this period of significant change.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2021

Cultured cardiac fibroblasts and myofibroblasts express Sushi Containing Domain 2 and assemble a unique fibronectin rich matrix

Highlights: • Cultured cardiac fibroblasts and myofibroblasts derived from normal human hearts express the novel marker SUSD2. • Under high density culture conditions, human cardiac myofibroblasts deposit a matrix scaffold rich in fibronectin. • Cultured dermal fibroblasts do not express SUSD2 and did not for form scaffolds in vitro. Cardiac fibroblasts and myofibroblasts assemble and maintain extracellular matrix during normal development and following injury. Culture expansion of these cells yield a bioengineered matrix that could lead to intriguing therapeutic opportunities. For example, we reported that cultured rat cardiac fibroblasts form a matrix that can be used to delivery therapeutic stem cells. Furthermore, we reported that matrix derived from cultured human cardiac fibroblasts/myofibroblasts converted monocytes into macrophages that express interesting anti-inflammatory and pro-angiogenic properties. Expanding these matrix investigations require characterization of the source cells for quality control. In these efforts, we observed and herein report that Sushi Containing Domain 2 (SUSD2) is a novel and consistent marker for cultured human cardiac fibroblast and myofibroblasts.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

Low background techniques applied in the BOREXINO experiment

The BOREXINO detector, located in the Gran Sasso National Laboratory in Italy, has been designed for real-time spectroscopy of low-energy solar neutrinos. Within the experiment several novel background reduction and assay techniques have been established. In many cases they are still the most sensitive world-wide. Developed methods and apparatus provided tools for a strict quality control program during the construction phase of the BOREXINO detector, which was the key to meet the background requirements. Achievement of extremely low background rate opened the possibility to probe in realtime almost entire spectrum of the solar neutrinos.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS1979

Quality assurance and control in the production and static tests of the solid rocket boosters for the Space Shuttle

The paper surveys the various aspects of design and overhaul of the solid rocket boosters. It is noted that quality control is an integral part of the design specifications. Attention is given to the production process which is optimized towards highest quality. Also discussed is the role of the DCA (Defense Contract Administration) in inspecting the products of subcontractors, noting that the USAF performs this role for prime contractors. Fabrication and construction of the booster is detailed with attention given to the lining of the booster cylinder and the mixing of the propellant and the subsequent X-ray inspection.

Cerny, O. F.↗
DOE OSTI2014

Specific recommendations for accurate and direct use of PET-CT in PET guided radiotherapy for head and neck sites

Purpose: To provide specific experience-based guidance and recommendations for centers wishing to develop, validate, and implement an accurate and efficient process for directly using positron emission tomography-computed tomography (PET-CT) for the radiotherapy planning of head and neck cancer patients. Methods: A PET-CT system was modified with hard-top couch, external lasers and radiotherapy immobilization and indexing devices and was subject to a commissioning and quality assurance program. PET-CT imaging protocols were developed specifically for radiotherapy planning and the image quality and pathway tested using phantoms and five patients recruited into an in-house study. Security and accuracy of data transfer was tested throughout the whole data pathway. The patient pathway was fully established and tested ready for implementation in a PET-guided dose-escalation trial for head and neck cancer patients. Results: Couch deflection was greater than for departmental CT simulator machines. An area of high attenuation in the couch generated image artifacts and adjustments were made accordingly. Using newly developed protocols CT image quality was suitable to maintain delineation and treatment accuracy. Upon transfer of data to the treatment planning system a half pixel offset between PET and CT was observed and corrected. By taking this into account, PET to CT alignment accuracy was maintained below 1 mm in all systems in the data pathway. Transfer of structures delineated in the PET fusion software to the radiotherapy treatment planning system was validated. Conclusions: A method to perform direct PET-guided radiotherapy planning was successfully validated and specific recommendations were developed to assist other centers. Of major concern is ensuring that the quality of PET and CT data is appropriate for radiotherapy treatment planning and on-treatment verification. Couch movements can be compromised, bore-size can be a limitation for certain immobilization techniques, laser positioning may affect setup accuracy and couch deflection may be greater than scanners dedicated to radiotherapy. The full set of departmental commissioning and routine quality assurance tests applied to radiotherapy CT simulators must be carried out on the PET-CT scanner. CT image quality must be optimized for radiotherapy planning whilst understanding that the appearance will differ between scanners and may affect delineation. PET-CT quality assurance schedules will need to be added to and modified to incorporate radiotherapy quality assurance. Methods of working for radiotherapy and PET staff will change to take into account considerations of both parties. PET to CT alignment must be subject to quality control on a loaded and unloaded couch preferably using a suitable emission phantom, and tested throughout the whole data pathway. Data integrity must be tested throughout the whole pathway and a system included to verify that delineated structures are transferred correctly. Excellent multidisciplinary team communication and working is vital, and key staff members on both sides should be specifically dedicated to the project. Patient pathway should be clearly devised to optimize patient care and the resources of all departments. Recruitment of a cohort of patients into a methodology study is valuable to test the quality assurance methods and pathway.

62 RADIOLOGY AND NUCLEAR MEDICINE↗