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Standalone performance evaluation of a CAD system provides information about the abnormality detection or classification performance of the computerized system alone. Although the performance of the reader with CAD is the final step in CAD system assessment, standalone performance evaluation is an important component for several reasons: First, standalone evaluation informs the reader about the performance level of the CAD system and may have an impact on how the reader uses the system. Second, it provides essential information to the system designer for algorithm optimization during system development. Third, standalone evaluation can provide a detailed description of algorithm performance (e.g., on subgroups of the population) because a larger data set with more samples from different subgroups can be included in standalone studies compared to reader studies. Proper standalone evaluation of a CAD system involves a number of key components, some of which are shared with the assessment of reader performance with CAD. These include (1) selection of a test data set that allows performance assessment with little or no bias and acceptable uncertainty; (2) a reference standard that indicates disease status as well as the location and extent of disease; (3) a clearly defined method for labeling each CAD mark as a true-positive or false-positive; and (4) a properly selected set of metrics to summarize the accuracy of the computer marks and their corresponding scores. In this lecture, we will discuss various approaches for the key components of standalone CAD performance evaluation listed above, and present some of the recommendations and opinions from the AAPM CAD subcommittee on these issues. Learning Objectives 1. Identify basic components and metrics in the assessment of standalone CAD systems 2. Understand how each component may affect the assessed performance 3. Learn about AAPM CAD subcommittee's opinions and recommendations on factors and metrics related to the evaluation of standalone CAD system performance., (© 2012 American Association of Physicists in Medicine.)

Purpose: The first medical physics Master's program in the Arabian Gulf region was started in 2002 at King Fahd University of Petroleum & Minerals (KFUPM), Dhahran, Saudi Arabia., Methods: After consulting with national and international representatives from the AAPM, IOMP, the University of Wisconsin-Madison and King Faisal Specialist Hospital and Research Center (KFSHRC) we constructed a versatile and rigorous curriculum. The program requires the completion of 7 core courses, 7 required labs, a minimum of 3 elective courses, a research project, a four-month clinical rotation and passing and a comprehensive examination. The success of the program required very close collaboration with national hospitals such as King Fahad Specialist Hospital in Dammam (KFSH-D), KFSHRC, and Riyadh Military Hospital. We cemented the collaboration with a formal agreement between KFUPM and KFSH-D, whereby the clinical medical physicists are actively involved in teaching lectures and labs, evaluating students' performance and co-supervising their clinical rotation and research projects. In order to prepare our graduates for their medical physics careers, we emphasize innovative learning methods such as students centered learning, execution of course projects, experiential learning and acquiring research skills and tools such as Monte Carlo simulations., Results: Our graduates have succeeded in securing clinical positions in some of the best hospitals in the region and achieved high employer satisfaction. Some students have gone to pursue their PhD's in North America and Europe. Many of our students succeeded in publishing their projects in international journals and international conferences. One of our students was instrumental in obtaining a US patent (US Patent # 785298) for an innovative x-ray tube design., Conclusions: We have achieved national recognition through the excellence of our graduates. In order to maintain high education quality standards and achieve international recognition, we are presently working to acquire IAEA approval and CAMPEP accreditation., (© 2012 American Association of Physicists in Medicine.)

Computer-aided detection/diagnosis (CAD) devices for radiology are becoming increasingly available for clinical use. To achieve the highest possible benefit from CAD systems, best practices are required for clinical implementation and use of CAD. This lecture will discuss four areas of interest to the medical physics community pertaining to CAD best practices: off-label use and pitfalls, user training, QA of CAD use, and academic opportunities for quality assurance (QA) research., Financial Disclosure: Patent royalties from and research agreement with iCAD; software license to Translational Sciences Corporation., Learning Objectives: 1. Understand benefits of PACS integration of CAD. 2. Identify potential issues with off-label use of CAD. 3. Understand the importance of user training relating to CAD devices. 4. Learn potential QA procedures to assure proper use of CAD as designed. 5. Learn about areas of CAD user training and QA that could benefit from further research., (© 2012 American Association of Physicists in Medicine.)

The rapid dose fall-off from treatment target to the adjacent critical organs has been the Holy Grail for radiotherapy treatment planning. The modern treatment delivery technologies to address such goal include volumetric modulated rotational therapy, non-coplanar EVIRT beams and the use of unflattened beams to reduce the penumbra area. In this lecture, the integration of above techniques will be presented to achieve the goal of a sharp gradient dose around the target and also the discussion of middle to low dose volumes. Use of volumetric modulated rotational therapy by multiple non-coplanar arcs is an idea treatment modality to focus the high dose in the target area while spreading the low dose to even larger volume to reduce the middle range dose to surrounding critical organs. This is especially important for SBRT treatment plans since the fraction dose is much higher than the traditional fraction schema. The challenges we face today are 1. the gantry-couch (patient) collision issue for non-coplanar beam angles, 2. the treatment delivery efficiency due to multiple arc rotations and 3. the massive inverse optimization computation for multiple rotational arcs can be resource intensive and time consuming for treatment plan systems. It might not be easy to resolve all the challenges at one time. However, the high efficient unflattened beam can certainly improve the delivery speed by reducing the beam- on time and this, again, is essential to SBRT patients with high fractional dose. In this lecture, the non-coplanar rotational therapy treatment planning techniques will be presented and be evaluated by using comformality index, gradient index as well as dose volume histogram comparison. The differences in treatment delivery time will be tabulated and compared. At the end, the high-medium-low dose volumes will be illustrated with radiobiological models for the philosophy of sun tanned versus sun burned., Learning Objectives: 1. Understand treatment plan and dose gradient advantages of using non- coplanar rotational therapy 2. Understand potential delivery efficiency by using unflattened beams for multiple non-coplanar rotational beams 3. Understand sun tanned versus sun burned: the low dose volume and integrated dose., (© 2012 American Association of Physicists in Medicine.)

Purpose: To improve the radiology residents' understanding of medical physics concepts through visualization of physical phenomena., Methods: Several medical physics concepts in x-ray transmission imaging are relevant to many radiographic modalities, not only to planar radiography. Therefore, it is important that the diagnostic radiology residents obtain a good understanding of these concepts. However, standard PowerPoint slides or blackboard-based graphical representations are not always effective ways to communicate these novel concepts to the residents. To improve upon the understanding of these concepts, the computer, projector and screen in the lecture room are used as surrogates of an x-ray imaging system. The projector is the source of light (x-rays) with PowerPoint slides defining the pattern emitted (x-ray field) on to the projector screen (detector/monitor). Several different transparencies and acrylic objects are used to demonstrate varied medical physics phenomena relevant to transmission imaging, such as: straight-line travel of electromagnetic radiation; tissue superimposition; object, subject, image and display contrast; linear systems; point spread functions; frequency domain; contrast and modulation transfer functions; quantum and image noise; noise frequency and noise power spectrum; anatomical noise; magnification and geometric unsharpness; inverse square distance relationship; sampling and aliasing; and x-ray scatter., Results: The residents' comprehension and ability to explain these concepts has substantially improved, in addition to their interest in these topics. This was reflected on improved test scores and on anonymous feedback surveys post- lectures., Conclusions: The use of demonstrations that mimic the conditions and physical phenomena found in transmission imaging by taking advantage of the projector and screen together with transparencies and other objects improves the residents' grasp of basic radiographic concepts and promotes live interactions between the residents and the medical physicist. Additional concepts that can be demonstrated in this manner are being sought., (© 2012 American Association of Physicists in Medicine.)

The use of an unfiattened photon beam for radiotherapy treatment is a new concept in the Radiation Oncology field. In the past, the non-optimal radiation area coverage obtained with unfiattened photon beams was of concern, and the flattening filter was introduced to overcome this pitfall. With the advance of technology, Intensity Modulated Radiotherapy (IMRT) emerged and non-optimal coverage was no longer an issue since the beam intensity could be modulated to obtain the desired target coverage. Unfiattened photon beams offer several advantages over flattened beams, namely: (1) they provide 2 to 4 times the dose rate, which significantly shortens the treatment time, especially for the high dose irradiation techniques, (2) they provide a purer beam spectrum, which is easier to model in a treatment planning system, (3) the head scatter is dramatically reduced, giving a lower dose outside of the field and (4) they provide a sharper penumbra, which makes planning easier. This lecture will provide an overview of the data collection, the treatment planning system (TPS) parameter modeling and the TPS validation for clinical implementation of unfiattened photon beams., Learning Objectives: 1. Understand the physics data collection and related issues. 2. Understand the TPS parameter modeling, planning validation and related issues. 3. Understand the optimal usage of unfiattened beams with clinical examples., (© 2012 American Association of Physicists in Medicine.)

Dose in CT has been a dominant topic in Medical Physics for at least a decade. This was for good reason since increasing use of CT necessarily led to an increase of cumulative dose to the population and inappropriate use of CT in some cases led to an unnecessarily high exposure of patients with subsequent coverage in the U.S. media. Fortunately, this situation also triggered a number of positive technical developments and fruitful initiatives worldwide. Currently, even "sub-mSv CT" is a realistic topic. However, we also engage in extensive discussions of the topic "CTDI and patient dose". They do not always seem to be pragmatic and sometimes are unnecessarily complicated. One reason may be that the topics computed tomography dose index (CTDI) and patient dose are seen necessarily combined. This lecture aims at discussing and hopefully helping to resolve some of the issues. Key points and suggestions are the following: • CTDI is a proven and reasonably good concept for scanner dosimetry and quality control (QC) on standard 64-row scanners. There is no major debate on CTDI efficiency and similar issues in Europe. • The new IEC scanner dosimetry concept to be used for wider detectors is acceptable; there is no need for new and heavy phantoms. • There still is a need of phantoms and concepts for QC of automated exposure control systems in CT. • CTDI should not and need not be changed and expanded to assess patient dose. • Patient dose estimates (both organ and effective dose) are based on air kerma measurements (without a CTDI phantom) and MC calculations using mathematical phantoms and/or voxel models. The DLP-to-E conversion which is accepted in Europe for more than a decade was based on this approach. • Patient dose estimates, both organ and effective dose, should be scanner- and patient-specific. Fast MC programs and dose software allow for this. Manufacturer cooperation is a necessity, and there are first positive examples. • The concept of diagnostic reference levels (DRL) which was started in Europe in the 1990s and is in wide use today has to be revisited. It need not be based on CTDI further on but, for example, on a revised scanner- and patient-specific DLP-to-E conversion. • An international consensus on the topics CTDI and patient dose appears desirable. All these points do not mean a revolution but rather aim at staying with established equipment. The two major objectives are to • avoid unnecessary QC burden of medical physicists who are threatened with extended CTDI measurements • provide more reliable and understandable information regarding patient dose in real time. Organ dose and effective dose are preferable to DLP., Learning Objectives: 1. Understand that CTDI is a technical concept for scanner acceptance and constancy testing 2. Learn about concepts for patient- and scanner-specific patient dose estimates 3. Learn about the concept of diagnostic reference levels and its strengths and weaknesses Research sponsored by Siemens Healthcare and by CT Imaging GmbH, both in Erlangen, Germany., (© 2012 American Association of Physicists in Medicine.)

As many as 6 - 8 million CT scans are performed annually in the United States on pediatric patients. The majority of these CT scans are not performed in pediatric hospitals that specialize in addressing the unique requirements of pediatric imaging. Instead, most of these scans occur in adult hospitals, where pediatric CT scanning is a small fraction of the total caseload. Both adult and pediatric hospitals need a simple method that allows the management of the CT radiation dose received by each patient based on the patient's physical size. This lecture suggests some simple tools and techniques that the qualified medical physicist can introduce to an individual practice in an effort to properly manage CT doses. This lecture begins by exploring the unique challenges presented by the pediatric patient in the management of their radiation dose during CT scanning. This is followed by an explanation of the basic science behind the development of the Size Specific Dose Estimate (SSDE) in CT, the strengths and weaknesses of the method, and some sample calculations. The presentation concludes by exploring the clinical application of SSDE in the day to day management of the radiation dose during CT scanning of not only small pediatric patients, but also patients who are larger than the average size adult., Learning Objectives: 1. Understand the basic challenges associated with CT imaging of children. 2. Understand the basic science used to develop SSDE, its strengths and its limitations 3. Understand the application of SSDE in the clinic in the daily management of pediatric CT doses., (© 2012 American Association of Physicists in Medicine.)

A significant advance in cancer therapy is currently underway with the evolution from a population-based to a personalized patient-based prescription. Rapid developments in imaging, particularly adoption of molecular imaging, offer unprecedented opportunities for accurate characterization of tumor biology, as well as early assessment of treatment response. Accurate characterization of tumor biology enables effective selection of appropriate therapy or even a design of purposefully non-uniform tumor-specific treatment plans, tailored to the spatial distribution of biological properties of each patient's tumor. Early assessment of treatment response enables treatment adaptation, potentially intensifying or reducing the treatment dose to provide more efficacious and less toxic therapies. However, integration of imaging into therapeutic applications requires a high level of image quantification, well beyond what is currently required in diagnostic imaging applications. This lecture will provide an overview of imaging applications in therapy, ranging from target selection totreatment response assessment. Potential roadblocks, as well as research opportunities on the path to personalization of cancer therapy, will be highlighted., Learning Objectives: 1. Understand the role of imaging in target definition and treatment response assessment 2. Understand the requirements for establishing imaging as a biomarker 3. Learn about research opportunities on the interface between imaging and therapy., (© 2012 American Association of Physicists in Medicine.)