bluuebunny/crossref_metadata_2025_split huggingface dataset:
SU‐FF‐T‐441: Validation of a New Serial Tomotherapy IMRT System
Authors: Pavord D 
Published: July 2007

Purpose: To evaluate the function and accuracy of a new serial tomotherapy system. Method and Materials: The new nomosSTAT IMRT system from Nomos Division of North American Scientific integrates several devices into one package. The new system removes the controller box from the Mimic collimator and transfers the functions to a computer placed in the accelerator control area linked to a touch‐screen monitor inside the treatment room. The new system is connected to the CORVUS planning station by standard network cabling, eliminating the need to transfer a plan via disk. In addition to automating the multileaf collimator control functions, the AutoCrane table indexing device is now computer controlled.The accuracy and reliability of the new system was validated. This included data transfer integrity, proper functioning of all controls, mechanical accuracy, and dosimetric accuracy. Multiple plans were transferred for both 1cm and 2cm treatment modes. Multiple table angle plans were also tested. Results: The plan data was found to be transferred accurately in all cases. The function of each control was verified as well as the ability to recover from an error. The mechanical accuracy of the AutoCrane device was found to be better than 0.1mm for the In/Out direction and 0.4mm for the Left/Right direction. The gantry angle inclinometers were found to be accurate to within 0.5 degrees when compared to an independent digital level. Two plans for each delivery width were verified with ion chamber and film measurements. The ion chamber measurements were within 3% of expected. Film dosimetry showed that at least 93% of pixels agreed within 4%, 4mm criteria. Repeat measurement of individual plans agreed within 1%. Conclusion: The new nomosSTAT system was therefore found to be acceptable for clinical treatment. Conflict of Interest: Research sponsored by Nomos Division of North American Scientific corporation.
SU‐FF‐T‐446: Verification of a Beam Model in a Treatment Planninng System Using An Monte Carlo Approach
Authors: Wieslander E , Knoos T 
Published: July 2007

Todays treatment planning systems (TPSs) have to be able to calcualate the dose distribution for very complex beams, i.e. highly modulated multi‐leaf collimator (MLC) beams, to meet clinical requirements. To achieve a high accuracy it is common to separate the dose calcualtion into a beam modelling phase, describing the beam exiting the accelerator, followed by a subsequent dose calculation in the patient.The aim of this work was to set up the Monte Carlo (MC) code system EGSnrc (incl BEAMnrc and DOXYZnrc) to study the head scatter as well as the transmission through MLC and diaphragms for an linear accelerator (Elekta Precise). These MC results are then be compared the beam model used in a commercial TPS (MasterPlan, Nucletron B.V.). Vendors data regarding the geometry of the treatment head of the linac was the basis for simulations performed with BEAMnrc. The collimation in the MLC direction consists of the leafs complemented with backup diaphragms. The characteristics of the electron beam, i.e. energy and spot size, impinging on the target have been varied to match measured data.Phase spaces from simulations of the treatment head were used to extract the scatter from, e.g., the flattening filter and the collimating structures. Similar data for the source models used in the TPS were extracted from the treatment planning system, thus a comprehensive analysis was possible.Simulations in a water phantom, with DOSXYZnrc, were used to study the modelling of the MLC and the backup diaphragm by the TPS. The results from this study will be helpful to understand the limitations of the model in the TPS and also providing knowledge for further improvements of the TPS source modelling.
MO‐A‐L100E‐01: Parallel Imaging: Techniques, Quality Control, and Applications (Preview of TG118 Repo
Authors: Clarke G 
Published: July 2007

Task Group ♯118 of the AAPM was established to describe the basis of parallel magnetic resonance imaging (pMRI) and its applications to the Medical Physics community. This presentation reviews the aspects of parallel imaging methods that have led to this technology becoming important clinically. The signature enhancement attributable to pMRI is faster MR image acquisition which leads to decreased motion artifact, reduced breath‐hold time, shorter durations of exams or more series acquired per exam. Increased flexibility is also achieved since parallel imaging has distinct advantages for limiting specific absorption rate (SAR) at higher magnetic field strengths.There are currently two general approaches to pMRI; one based on image‐space reconstruction and the other on k‐space based methods. Details of the design of RF coils, or the entire RF systems, for improving imaging performance in pMRI will be surveyed. Additional benefits may be derived from the use of pMRI in balanced gradient echo imaging, fast spin echo imaging, dynamic MRI, BOLD contrast MRI and diffusion MRI. In addition, the image quality trade‐offs in pMRI will be considered with particular focus on the different ways that signal and noise are handled in pMRI image reconstruction.Finally advanced results, which will likely lead to continuing improvements in pMRI technology, will be discussed. In summary, this presentation will provide practical guidance and assistance for the practicing medical physicist so that pMRI may be more readily applied and understood within the clinical environment.By the end of this presentation the attendee should:1. understand the basic concept of parallel imaging and how it can be used to reduce the acquisition time of MR images.2. recognize in which clinical protocols the use of parallel imaging methods is most advantageous and what benefits are bestowed on each.3. be aware of the image quality trade‐offs involved in implementing pMRI and4. understand the new image artifacts inherent with this approach.
MO‐A‐M100J‐02: Performance Evaluation for New‐Technology CT Systems: 256‐Channel C
Authors: Geleijns J 
Published: July 2007

Medical physicists are challenged to assess image quality and patient dose for 256‐channel CT scanners. Whereas current concepts for measurement of image quality still remain valid for 256‐channel scanners, concepts for CT dosimetry will have to change fundamentally. Current methodology for CT dosimetry, e.g. assessment of CTDI with a 10 cm CT ionization chamber and standard CT dose phantoms, is not compatible with the x‐ray beam geometry of the new 256‐channel CT scanner. The beam width exceeds the length of the CT ionization chamber and, at the exit surface of the phantom; the beam width even exceeds the length of the body phantom. Several options to overcome dosimetric problems of cone beam CT scanners will be considered.Educational Objectives:1. Understand the design and operation concepts a new 256‐channel axial CT scanner.2. Understand concepts for specifying and measuring absorbed dose for a new 256‐channel axial CT scanner.3. Understand shortcomings in current concepts for assessment of absorbed dose and and patient dose for the new 256‐channel axial CT scanner.
MO‐A‐M100F‐01: Integrating the Healthcare Enterprise (IHE) in Radiation Oncology: Will It Help You?
Authors: Curran B 
Published: July 2007

Initiated in 2005, Integrating the Healthcare Environment for Radiation Oncology (IHE‐RO) is a multi‐society, multi‐vendor effort to improve the safety, reliability, and integration of computer and information systems within the radiation oncology arena. IHE‐RO works to accomplish this by coordinating the use of standards such as DICOM and HL7 to effectively exchange information between diverse computer systems involved in the process of planning and delivery of radiation therapy treatments. It attempts to remove ambiguity where it exists in these standards by defining consensus profiles to solve real‐world situations.Each IHE domain (radiology, cardiology, radiation oncology, …) identifies areas where improvements need to be made in the sharing / exchange of information between disparate systems. An IHE Planning Committee then defines a real‐world use case illustrating this process and a trial Integration Profile for improving it. This profile is then discussed by the Technical Committee, which defines the specific standards and methods for exchanging information that will be used to satisfy the needs of the profile and use case. Finally, the Integration Profile and detailed implementation specifics are published in the domain's Technical Frameworks documentation.Once published, those vendors participating in the IHE process develop / refine products to meet the Integration Profile's requirements. Testing occurs via test tools developed for the profiles and then demonstrated in a formal Connectathon, held under the auspices of the society sponsoring the domain. Companies that successfully demonstrate their compliance with the profile are then included in a public demonstration, held at the society's annual meeting. The complete process from profile initiation to public demonstration typically takes 20–24 months.In this session, the progress of the IHE‐RO effort will be reviewed. The profile selected for demonstration at the ASTRO 2007 Annual Meeting will be discussed. The proposed profiles for 2008 will be compared, and the rationale for those selected for inclusion in the 2008 demonstration will be given. Profiles developed within other IHE domains, such as Information Technology Infrastructure, will also be discussed.Educational Objectives:1. To describe the structure and purpose of the IHE effort, including a brief history of IHE and the formation of the IHE‐RO effort.2. To review the development process of the 2007 IHE‐RO profile; how it was developed, its benefits, and its limitations.3. To discuss the profiles currently under consideration for future IHE‐RO efforts, particularly the 2008 public demonstration.4. To describe efforts in other IHE domains that may influence the development of information systems in radiation oncology.
MO‐SAMS‐L100J‐01: Digital Mammography Update: Design and Characteristics of Current Systems
Authors: Pfeiffer D 
Published: July 2007

Mammography still remains the best screening tool for early detection of breast cancer, and the recent ACRIN DMIST results draw attention to the fact that digital mammography is better at detecting cancers in dense breasts. Digital mammography equipment has continued to develop and improve and more vendors and models have entered the marketplace with FDA approval. The technology used in these systems generally falls into four main categories: direct capture detectors, indirect capture detectors, slot scanning, and cassette‐based storage phosphors (computed radiography). Additionally, a photon counting system is being developed. Each of these technologies has its advantages and disadvantages. A review of the systems currently available is presented, including the detector technology utilized. Features of these systems are also presented. This is a Self Assessment Module (SAM) to help fulfill the requirements of the Maintenance of Certification (MOC) process as defined by the American Board of Radiology (ABR). As such, audience participation through interactive questions will be provided during the course of the lecture.Educational Objectives:1. Become familiar with the detector technologies currently used in digital mammography systems.2. Become familiar with the digital mammography systems available from each manufacturer.3. Become familiar with the unique elements of each system.
MO‐SAMS‐L100J‐02: Digital Mammography Quality Assurance: Comparing the Manufacturers Recommendations
Authors: Berns E 
Published: July 2007

Digital mammography is quickly becoming the technology of choice for breast imaging with several FDA‐approved systems already available and more on the way. Digital detectors in mammography have different characteristics compared to the traditional screen‐film systems and require by the FDA different Quality Control tests. This lecture is going to discuss the practical issues for the medical physicist who wants to learn the differences in these Quality Control tests and how they impact the mammography facility and ACR accreditation. The lecture will be broken into several parts. The first will review currently available FFDM equipment and their respective Quality Control tests. The second part will compare similar QC tests and discuss the key differences. The third part will review quality control for review workstations and laser printers designed for digital mammography.Educational Objectives:1. To describe current quality control procedures for FFDM systems.2. To describe current quality control procedures for review workstations in digital mammography.3. To describe current quality control procedures for laser printers in digital mammography.4. To review the impact of QC on ACR accreditation for FFDM systems.
MO‐SAMS‐AUD‐02: Frequencies, Tolerance Limits, and Action Levels for IMRT QA
Authors: Palta J 
Published: July 2007

Each intensity‐modulated radiation therapy (IMRT) field includes many small, irregular, and asymmetric fields that completely obscure the relationship between monitor unit (MU) setting and radiation dose. Uncertainty and inaccuracy of dose delivery with IMRT is primarily attributed to the leaf positioning accuracy, modeling of radiation output for small field sizes, modeling of beam penumbra, and the dose outside the IMRT field. Dose‐difference distribution, distance‐to‐agreement (DTA), and a numerical gamma index are often used to evaluate the quality of agreement between measured and calculated dose distributions for the IMRT fields. The tolerance limits based on these indices for IMRT QA are often not adequate because all these methodologies do not account for space‐specific dose uncertainty information. In other words, single tolerance criterion is applied to all test points even when dose uncertainty is significantly different from point to point. At any given point, the dose uncertainty depends on different levels of dose and gradients from multiple small beams rather than that of the overall dose profile. Therefore, new methodologies are needed that determine dose uncertainties based on the dose level and gradient information of each small field.In IMRT, it is sometimes difficult to have agreement between calculation and measurement of dose at all points in a 3‐D dose distribution. A disagreement at a few points does not necessarily lead to negative overall result if other comparable points are well within the established tolerance limits. We will describe a new approach in establishing tolerance limits and action levels for IMRT QA that will ensure delivery of prescribed radiation dose within an acceptable limit of 5%.Educational Objectives:1. To describe the uncertainties in IMRT planning and delivery.2. To describe the impact of spatial and dosimetric uncertainties on the IMRT dose distribution.3. To describe the limitations of current methodologies of establishing tolerance limits for IMRT QA.4. To describe new methodologies for establishing tolerance limits for IMRT QA.
MO‐B‐M100J‐01: Determination of Dose to Individual Patients in Radionuclide Imaging Procedures Including Planar, SPECT, and PET
Authors: Williams L 
Published: July 2007

Patient absorbed dose estimation due to internal emitters requires two separate computations prior to using the D = S*Ã formula. Here, D is the desired vector of target organ doses, S is a rectangular matrix of dose per radiodecay and Ã is a vector of cumulated activity curves for the various source organs in the patient. While S may be accessed from tabulations such as the OLINDA program from Vanderbilt University, Ã may be computed only by integrating activity curves A(t) out to sufficiently long times. Several methods are available to determine the activity in a given source organ. One may have tissues or lesions near the surface so as to use inverse square computations. At depth, the observer can use gamma cameras and a geometric mean image (GM), CT assisted matrix inversion (CAMI) or quantitative SPECT imaging. In the latter two cases, hybrid imaging devices such as SPECT/CT make the computations easier since image registration is greatly facilitated. There is also a possibility of PET/CT hybrid images being implemented with the SUV value being used to find the activity at‐depth. Lack of suitable positron labels makes PET studies problematic in the case of a general radiopharmaceutical, however. Errors in activity quantitation are typically on the order of +/− 30%, although they can be much larger in geometrically complicated cases. Two types of S values are commonly used. In type I computations, S refers to a phantom of appropriate size; e.g., adult male or female. Such dose estimates are included in applications to regulatory agencies (e.g. FDA). Additionally, type I results may be used to compare similar radiopharmaceuticals with regard to absorbed dose levels. Both diagnostic and therapeutic radiopharmaceuticals may be of interest. Type II calculations usually refer to a specific patient undergoing internal emitter therapy. Generally, alpha or beta emitters are used in this context. One may use Monte Carlo (MC) methods to find the S or correct tabulated phantom S elements to those approximating the patient. Since therapy involves short‐range emitters, S becomes diagonal and the correction is done via; S(patient) = S(phantom)*organ mass (phantom)/organ mass (patient). Such corrections can be very large — on the order of factors of two‐ or three‐fold. Finally, the uncertainty in the dose values may be estimated by combining errors in both S and Ã.Educational Objectives:1. Understand the matrix equation D = S*Ã for estimating internal emitter radiation doses to target organs.4. Know the various methods to estimate source organ activity.5. Realize that there are two types of calculations for dose; standard phantom or patient‐specific.6. Know how to estimate uncertainties in the dose calculation.
MO‐D‐M100F‐01: Emerging Techniques Using Digital Tomosynthesis
Authors: Yin F 
Published: July 2007

In‐room radiolographic imaging systems is being rapidly implemented in routine clinical operations for target localization. A typical system consists of a kV x‐ray source and an amorphous‐silicon flat panel detector mounted orthogonally to the MV‐beam axis. The available clinical imaging capabilities from this configuration are 2‐D radiographic or fluoroscopic imaging and 3‐D CBCT. These techniques may have potential limitations either on not sufficient anatomical information for positioning verification (such as 2‐D technology) or long imaging time (several breathing cycles), mechanical constraints, and excessive dose to the imaging volume (such as CBCT technology). Therefore, limited‐angle digital tomosynthesis (DTS) is being investigated as an alternative 3‐D imaging technique. Much of the investigations have been focused on the clinical feasibility and efficacy of using DTS for on‐board target localization and comparison between DTS technology with 2‐D radiographic and CBCT technologies. This talk will summarize emerging clinical research to develop the DTS technology for on‐line patient positioning and target localization for image guided radiation therapy, specifically for anatomical sites of head and neck, abdomen, breast and prostate.Educational Objectives:1. Brief review of DTS imaging technique in the treatment room.2. Clinical feasibility and efficacy of using DTS for in‐room target localization.
MO‐D‐M100F‐04: In‐Room Imaging for Treatment of Lung and Breast Cancer
Authors: Galvin J 
Published: July 2007

New in‐room IGRT techniques for treatment of targets in and around the lungs allow margin reduction compared to the use of more traditional MV radiographic verification techniques. Unlike targets in the head & neck, liver or prostate, the lung is interesting in that tumors are frequently easily visualized so that the use of surrogates is not always necessary. This is particularly true for volume imaging devices that can produce thin sections through the patient in various different orientations. These devices include diagnostic quality helical CT scanners placed in the treatment room in close proximity to the treatment unit as well as various MV or kV Computer Tomography approaches that use the capabilities of or simply attach to the treatment unit structure. Devices that use kV photons to produce dual stereoscopic 2D views of the patient do not allow such easy visualization of lesions in the lungs, but they are extremely helpful when reliable anatomic surrogates can be identified, or when fiducial markers can be surgically placed to identify the target position.Hypofractionated dose schedules are gaining popularity for treatment of some early diagnosed non‐small cell lung cancers. Treating these tumors to a high dose in just a few fractions is challenging in that field placement is critical. In‐room IGRT has played an important role in positioning these treatment fields with the required accuracy. Treating the breast, another structure in the thorax region, presents a somewhat different challenge in that this part of the patient's anatomy is hard to reproducibly position for each day of treatment. In‐room IGRT can also be used to advantage to treat this structure. This is particularly true for the boost portion of the treatment.Treating in or near the thorax is complicated by the fact that targets can move as a result of respiratory and/or cardiac motion. When breath hold, abdominal compression to damp a tumor's trajectory, target tracking, or treatment unit gating techniques are employed to control the effects of respiratory motion, using IGRT to verify patient positioning prior to treatment will not necessarily guarantee acceptable tumor targeting during dose delivery. However, the use of real time in‐room kV and MV fluoroscopy can provide extra information that is useful for this level of verification.Using the new IGRT techniques does not assure that apertures are correct in terms of either their shape or orientation. Thus, it is important to combine the new IGRT techniques with the older standard approach. That is, portal imaging using the MV beam and treatment apertures remains an important step in the overall QA process.1. To understand the design, functioning, advantages, and limitations of the different IGRT systems used for treating in and around the thorax region.2. To understand how different IGRT systems can be used to provide the information needed to target moving lesions in the thorax region.3. To understand the workflow issues for IGRT used to treat targets in the thorax.
MO‐D‐M100F‐05: Latest Clinical Development for H&N and CNS
Authors: Wu Q 
Published: July 2007

Daily target localization is a critical step to ensure accurate delivery of 3‐D conformal radiation therapy and intensity‐modulated radiation therapy. Current in‐room localization technologies for HN and CNS treatment include 2D kilovoltage (kV) or megavoltage (MV) radiography, CT on‐the‐rail, cone beam CT (CBCT), megavoltage CT (MVCT), and optical guidance systems.This lecture will provide an overview of the current in‐room target localization technologies for HN/CNS treatment, including the system design and characteristics, patient alignment process, and their integrations in clinical workflow. The accuracies of these technique and consequently the margin considerations will be discussed.Educational Objectives:1. Understand the latest commercial available in‐room localization techniques for HN treatment.2. Understand the accuracies of these localization systems.3. Understand the margin considerations associated with using these systems.