bluuebunny/crossref_metadata_2025_split huggingface dataset:
TU‐C‐211‐04: Time‐Resolved Cone‐Beam CT for Cardiac Interventions
Authors: Lauzier P Theriault , Tang J , Chen G‐H 
Published: November 2011

Purpose: To obtain artifact‐free 3D images with high temporal resolution from truncated projection data recorded using a cardiac interventional system with a slowly rotating gantry and a small flat‐panel detector. Methods: In order to reconstruct time‐resolved cardiac images from truncated projections, one must be able to achieve ultra‐high temporal resolution, while also mitigating truncation artifacts. Both of these goals can be achieved using an adapted implementation of the prior image constrained compressed sensing (PICCS) algorithm. To demonstrate this, a canine animal model was scanned in vivo using an interventional C‐arm system with a 40×40 sq cm detector in a single rotation 14‐second acquisition. The projections were artificially truncated to simulate the use of a 20×20 sq cm detector commonly used in many cardiac intervention suites. The projections were gated retrospectively using the recorded ECG signal into 20 cardiac phases. The data from each phase were reconstructed using the PICCS algorithm. The reconstruction accuracy was assessed by evaluating image quality of both truncated and non‐truncated datasets. Results: The images reconstructed from truncated data using the PICCS algorithm resulted in a root mean square deviation of about 2.5% with respect to the non‐truncated data. Furthermore, the truncated PICCS reconstructions did not contain artifacts that plagued the images reconstructed using the FDK algorithm from the same datasets. The temporal resolution achieved in this study was about 33 ms. The PICCS reconstructions were generated in under 2 minutes per phase for a 256×256×128 image volume using a GPU‐based implementation. Note that the reconstruction of each phase can be processed in parallel. Conclusions: Artifact‐free time‐resolved cardiac imaging is achievable using a cardiac intervention C‐arm system with a slowly rotating gantry and the PICCS algorithm. Further optimization could bring the reconstruction time to a level adequate for the interventional setting.Grant from GE Healthcare (Waukesha, WI)
TU‐C‐301‐01: Going Paperless in a Radiation Oncology Clinic
Authors: Jani S 
Published: November 2011

There are numerous important advantages of going paperless in a radiotherapy clinic. This process can be challenging in many ways. In this session, we share practical details on how a clinic can go paperless. In the first presentation, I will describe this process with Elekta Mosaiq software. The second presentation covers the process with Varian Aria software.The MosaiQ software V2.0 supports three radiotherapy departments, two infusion centers and a specialty wound care clinic at Sharp Healthcare system. All the facilities are within 20 miles from each other. Prior to initiating the paperless process, we acquired a crucial software program, Adobe Acrobat 9 Pro with multiple licenses. We also purchased Fujitsu fi‐ 6130 document scanners, another critical component in our success.The first section to go paperless was the Physics/Dosimetry area. All treatment plans from ADAC Pinnacle and BrainLab BrainScan are converted to PDF files, electronically signed by the planner and stored in MosaiQ under Diagnosis and Interventions. These documents can then be approved by the radiation oncologist and physicist prior to treatment. We also created Word templates in the document section to support billing and special procedures, such as physics consults, special treatment procedure notes, and QA documents.Making full use of the Quality Check List feature was next. Simulation orders, dosimetry tasks, new patient QA, chart checks, chart rounds and close‐out QA of electronic charts are all performed electronically through MosaiQ. For each of these steps, a Quality Check List (QCL) was created and employed so that no critical procedures go un‐documented.Billing has been electronic using HL7 interface for many years at Sharp Healthcare.Finally, the outside reports such as imaging and surgical notes, past H & P, nursing notes, etc, from applications like Cerner, Synapse, are transferred to MosaiQ using the “Print to File” function of Acrobat 9 Pro. Any remaining documents can be scanned and saved as PDF in the patientˈs EMR.In our experience, the first 5% and last 5% of going paperless took the longest. The process has been painless as well as fun. If there is one factor above all, though, to ensure success, it is having the staff on‐board. Everyone, from the radiation oncologists to the front office personnel, recognizes the value in eliminating paper charts in the department, and has helped to make it happen seamlessly and successfully.Learning objectives are:1. understand the benefit of going paperless in radiotherapy clinic2. understand the steps required and optimal sequence to transition from paper to electronic medical records3. understand the value of safeguards such as redundancies, double‐ checks, etc that should be placed for safe delivery of radiation
TU‐E(SAM)‐211‐02: Role of the Medical Physicist in Clinical Implementation of Breast Tomosynthesis
Authors: Liu B 
Published: November 2011

FDA recently approved Hologic Selenia Dimensions Tomosynthesis system for 3 dimensional breast imaging. Many new systems will be installed in the near future. To properly support the implementation of this new modality, clinical physicists need to understand unique operation conditions of the tomosynthesis system, shielding requirements, factors affecting image quality and patient dose, sources of image artifacts, in addition to knowing the basic principles of tomosynthesis image acquisition and reconstruction.This talk will focus on the implementation and acceptance test of Hologic Selenia Dimensions tomosynthesis system. The operation modes, typical acquisition parameters, x‐ray beam characteristics, system performance in terms of image quality and patient dose will be described. The impact of unique imaging acquisition parameters on shielding requirements will be discussed. The acceptance tests which are unique to the tomo modes will be illustrated.Learning objectives:1. Understand the typical operation modes of Hologic tomo system and image acquisition parameter range.2. Understand the achievable system performance of Hologic tomo system in terms of image quality and patient dose.3. Understand the impact of the unique tomo image acquisition parameters on room shielding requirement4. Understand major factors influencing the image quality and patient dose5. Know how to perform the acceptance test.
TU‐E‐224‐01: The Role of Voluntary versus Mandatory Regulatory Standards
Authors: Balter S 
Published: November 2011

The patientˈs skin and the lens of the eye are the critical tissues for most fluoroscopically guided interventional procedures. Risks include hair loss, skin toxicity, and radiogenic cataracts. Appropriate dosimetric feedback to the operator contributes to optimizing benefit‐risk. Ideally, interventional fluoroscopes should provide real‐time feedback via a continuously updated dose maps and accurate estimates of peak skin dose. Such technology is not generally available in 2011. However, a variety of real‐time and post‐procedure tools are currently available for managing fluoroscopic skin irradiation. Equipment conforming to IEC 60601‐2‐43 (2000, 2010) displays fluoroscopic time, PKA and Ka,r at the operatorˈs working position. All fluoroscopes sold in the USA after mid 2006 displays fluoro‐time and Ka,r. Various film and detector arrays have been used to obtain post‐procedure dose maps for more than a decade.Newer fluoroscopes and third‐party dose monitoring systems are beginning to offer useful proprietary dose mapping in angular space (defined by gantry angles) in both real‐time and post‐procedure flavors. Initial commercial deliveries of the DICOM Radiation Dose Structured Report (RDSR) provide detailed post‐procedure procedural information in enough detail to facilitate detailed dose reconstruction. Data in the RDSR is in defined public fields to facilitate accessibility. The relevant DICOM and IEC standards include specifications for real‐time streaming of the data. This will facilitate the development of independent real‐time dose modeling. This lecture will review the technologies available in 2011 and will provide an estimate of future time‐lines in this area. It will also include a discussion of the use of complete sets of dosimetric data as part of the quality process.Learning Objectives:1. Understand the advantages and disadvantages of currently available dose monitoring technologies.2. Understand the evolution toward real‐time skin dose mapping.3. Understand how standardized dosimetry can be incorporated into a QA program.
TU‐E‐224‐02: The Role of Voluntary versus Mandatory Regulatory Standards
Authors: Pizzutiello R 
Published: November 2011

Standards are essential to providing practitioners with a uniform set of tools to use to deliver healthcare to the public. Image the limitations imposed in previous generations when radiation dose was “measured” by the “Skin Erythema Dose.” The development and widespread use of the concept of absorbed dose to organs created a new paradigm that opened the door to the modern era of Radiation Medicine.The current absence of uniform standards for dose display limits our ability to use dosimetry information effectively in the clinical decision support process. The development of Standards has historically evolved from Educational, through Voluntary and ultimately to Regulatory implementation. Our experience with Mammography since the late 1980ˈs provides helpful context. When MQSA was enacted, only 25% of the mammography facilities in the USA were accredited.Todayˈs Regulatory Standards in the USA start with the familiar FDA Product Standards, and are now supplemented and strengthened by emerging Professional and Reimbursement Standards.How can AAPM, COMP and other members of the Radiation Medicine community help to create Dose Display standards that are meaningful, practical, and most importantly support the clinical decision making process?
TU‐E‐BRA‐02: How Should We Verify Complex Radiation Therapy Treatments ?
Authors: Ibbott G , Oldham M , Mijnheer B , Zhu T 
Published: November 2011

The critical importance of comprehensive treatment verification to patient safety is a topic of major current interest. The increase in complexity of modern treatments has created a direct need for correspondingly more sophisticated and comprehensive verification tools. A variety of new dosimetry techniques, QA devices, and verification rationale have recently emerged with potential to transform the process of both commissioning and routine patient treatment verification. A common goal of many of these systems is a more comprehensive measurement of the delivered dose in 3‐dimensions (3D) with high accuracy and spatial resolution. Several of these 3D or semi‐3D systems can also measure delivered dose in moving phantoms, and can therefore address important verification questions in 4D. Other approaches are capable of estimating the in‐vivo dose delivered to patients by back‐projecting measured exit fluence acquired during treatment. This symposium aims to review both the clinical rationale and clinical implementation of these important developments in complex treatment verification. Speakers will address the following topics in the context of clinical verification of advanced treatments like IMRT, VMAT/RapidArc, tomotherapy, and SRS/SBRT etc): 1) EPID dosimetry — both in‐vivo and ex‐vivo, 2) dosimetry with diode and chamber arrays, 3) 3D dosimetry with radiochromic plastics and gels, 4) computational algorithms for independent verification. The characteristics, state‐of‐the‐art, limitations, and clinical experience from these techniques will be reviewed.Learning objectives:1. gain insight into the dosimetric challenges posed by advanced radiation treatment techniques2. appreciate the importance of comprehensive treatment verification to patient safety3. understand the rationale and capabilities of dosimetry techniques for comprehensive treatment verification, both in‐vivo and ex‐vivo
TU‐E‐BRB‐06: Monte Carlo Simulations of a Novel Kilovoltage Radiotherapy Source
Authors: Bazalova M , Weil M , Graves E 
Published: November 2011

Purpose: To study the depth‐dose delivery of a novel kilovoltage source using Monte Carlo (MC) simulations. Methods: The large area scanning beam x‐ray source (SBDX) designed for fluoroscopic imaging was modeled for diverging and converging beamlets. The MC model of SBDX was built in the EGSnrc/BEAMnrc code and validated against EBT Gafchromic film measurements in the DOSXYZnrc code. The SBDX was modeled as a number of highly collimated 120 kV x‐ray sources distributed along a line. Simulations were performed of the source arcing around a target beneath the surface in a soft tissue human‐sized phantom. The design of the source was optimized to minimize skin dose with a high beam output. A comprehensive study of the source design included the investigation of incident electron beam arrangement, and collimator design, as well as x‐ray delivery setup, such as the source‐to‐surface distance and beam angles. Results: SBDX depth dose curves for three energies simulated by MC agreed with the measured ones to within 5%. The comprehensive study of the sourceˈs design parameters and x‐ray delivery setup determined optimum parameters for high depth‐to‐skin ratios and beam output of the novel 120 kV source. With these parameters, a 4‐cm diameter, subsurface target was covered with a 75% isodose line, and the corresponding target‐to‐skin ratio was 2.74. Another set of source parameters resulted in a target‐to‐skin ratio of 3.03, however, the beam output was by 80% lower. Conclusions: The dose distributions created with a novel kilovoltage source have been studied using MC simulations, and a possible design for clinical use has been determined.Sirius Medicine, LLC provided the presenting author with financial support to conduct the research.
TU‐E‐BRB‐08: Dosimetric Impact of Metal Artifact Reduction in Treatment Planning: Phantom and Clinical Studies
Authors: Chen D , Chetty I , Glide‐Hurst C 
Published: November 2011

Purpose: To systematically evaluate, in phantom and patient, dosimetric differences obtained by applying metal‐artifact reduction (MAR) algorithm in CT for treatment planning algorithms. Method and Materials: Helical CTs were acquired for six phantom configurations and three patient cases (bilateral hip prostheses, femur, humerus rods). MAR was applied to reconstructed images using Matlab (v7.8) integrated into Extended Brilliance Workspace research platform (Philips Healthcare, Cleveland, OH). Two Cerrobend rods were fabricated for CIRS thorax phantom to investigate interfaces and simulated clinical configurations including bilateral hip prostheses. Dose was calculated on original and MAR‐corrected CTs using Anisotropic Analytic Algorithm (AAA), Pencil Beam Convolution (PBC) in Eclipse, Pencil Beam Convolution (PBC‐BL) and Monte Carlo (MC) algorithms in Brainlab, with and without heterogeneity correction. Dose matrices were evaluated. Statistics from the same regions of interest evaluated sensitivity and accuracy of algorithms between original and MAR‐corrected CTs. Results: In phantom, with heterogeneity correction off, no appreciable dose differences were observed between original and MAR‐corrected CTs. ∼4.0% mean dose difference was observed between original and MAR‐corrected scans for single Cerrobend rod interfaced with lung‐mimicking tissue when calculated with MC. For double Cerrobend configuration, lung‐metal‐bone interfaces yielded 3.0% and 5.0% difference in mean dose for AAA and MC, respectively. For the patient data, dose differences between the original and MAR‐corrected CT scans could be substantial. With the exception of PBC in Eclipse, up to 8 +/− 24% mean dose differences were observed for the 3D conformal plans. The most substantial dosimetric changes were revealed for the MAR‐ corrected bilateral hip prostheses scan, with 12 +/− 29% mean dose differences observed for both PBC and MC implemented in Brainlab. Conclusion: Dosimetric differences revealed between original and MAR corrected CT scans can be substantial, and the results can be used to facilitate implementation of MAR corrected images in treatment planning.Henry Ford Health Systems holds a research agreement with Philips Medical Systems.
TU‐E‐BRB‐09: Development of a GPU‐Based Monte Carlo Dose Calculation Package for Cancer Radiotherapy
Authors: Jia X , Gu X , Graves Y , Jiang S 
Published: November 2011

Purpose: Monte Carlo (MC) simulation is commonly considered as the most accurate dose calculation method in radiotherapy. However, its efficiency still requires improvement for many routine clinical applications. The goal of this work is to develop a GPU‐based MC dose calculation package, gDPM. It utilizes the parallel computation ability of a GPU to achieve high efficiency, while maintaining same particle transport physics as in the original DPM code and hence simulation accuracy.Methods: The gDPM code is implemented on GPU architecture under CUDA platform. In GPU computing, divergence of execution paths between threads can considerably reduce the efficiency. Since photons and electrons undergo different physics and hence attain different execution path, we design a simulation scheme where photon transport and electron transport are separated to partially relieve the thread divergence issue. High performance random number generator and hardware linear interpolation are also utilized. We have also developed various components to account for fluence map and linac geometry, so that gDPM can be used to compute dose for real IMRT or VMAT treatment plans. The gDPM is tested for its accuracy and efficiency in both phantoms and realistic patient cases. Results: In all cases, the average relative uncertainties are less than 1%. Dose difference between CPU and GPU results is less than 3% of maximum dose in over 98% high dose region. A t‐test is also performed and the dose difference is not statistically significant in over 98% high dose region. Speed up factors of 57.3∼75.5 have been observed using an NVIDIA Tesla C2050 GPU card against a 2.27GHz Intel Xeon CPU processor. Dose calculation for a real IMRT head‐and‐neck plan and a VMAT prostate plan can be finished in 48sec and 46sec, respectively. Conclusions: The gDPM package has achieved high computation efficiency on GPU without losing accuracy.This work is supported in part by the University of California Lab Fees Research Program. GPU cards are partly provided by NVIDIA.
TU‐E‐BRB‐10: Investigation of the Water‐to‐Air Stopping Power Ratio for Carbon Ion Beam Dosimetry Based on Experimental Data and FLUKA Simulation
Authors: Sanchez‐Parcerisa D , Gemmel A , Parodi K , Jäkel O , Rietzel E 
Published: November 2011

Purpose: Water‐to‐air stopping power ratio (Sw,air) is currently known with an uncertainty of 2% for carbon ion beams (IAEAˈs TRS‐398), and it is the main source of uncertainty in absolute dosimetry with air‐filled ionization chambers. We present here a more precise calculation of its value from measurements performed under controlled experimental conditions Methods: Sw,air is given in TRS‐398 as a particle fluence weighted average over all particles and energies, and it is derived from track‐lenght fluence of each particle in water and its mass stopping powers in water and air. All these quantities were calculated with the general‐purpose Monte Carlo code FLUKA. The input values to the code, including water and air mean ionization potentials of Iw = 75.9 ± 0.2 eV and Iair = 87 ± 3 eV, were chosen in accordance to experimental measurements of mono‐energetic carbon ion beams carried out at the Heidelberg Ion Therapy Center (HIT). The Sw,air was calculated for spread‐out Bragg Peaks (SOBPs) at different depths, and a possible dependence on the residual range was investigated. Results: For all the studied SOBPs, the uncertainty in the stopping power ratio could be reduced significantly by introducing a logarithmic dependence on the residual range. Moreover, using the fixed value of Sw,air =1.13 causes, on average, a dose underestimation of 0.1 % if used in the plateau area and of 0.4% if used n the peak (compared to Monte Carlo data), whereas using our Sw,air(z) model reduces this dose underestimation below 0.05% in all cases. Conclusions: The contribution presents a revised calculation of the water‐to‐air stopping power ratio using own experimental data that reduces significantly the uncertainty of the current reference value.The research leading to these results has received funding from the European Communityˈs Seventh Framework Programme 2007–2013 under grant agreement n° 215840‐2 (PARTNER).
TU‐E‐BRC‐11: Clinical Impact of Dose Mapping Sensitivity to Deformable Image Registration Parameter Selection
Authors: Salguero F , Siebers J 
Published: November 2011

Purpose: 4D dose mapping accuracy is limited by the accuracy of the displacement vector fields (DVF) generated by deformable image registration (DIR) algorithms. DIRs depend on user adjustable parameters whose election may result in different resulting DVFs. This work evaluates the clinical impact of DIR parameter selection on 4D accumulated doses. Methods: A 180 cGy/fraction PTV dose clinical treatment plan is generated, with dose calculated on each phase of a ten‐phase 4D lung CT image. Per‐ phase doses are mapped to a reference phase using DVFs from the demons DIR implemented in a research version of Pinnacle 9.1 for dose accumulation using a variety of settings for DIR user‐adjustable parameters. Dose‐volume histograms, TCP, and NTCP values are evaluated for each accumulated dose as are differences in accumulated dose values. Results: Cumulative dose values vary with the user adjustable parameters. The maximum dose difference is 62.5 cGy/fraction when the number of image filter histogram bins changes from 32 to 16 and 14.9 cGy/fraction when the number of level 4 iterations (where the image is downsampled to 1/8 of the original resolution) changes from 50 to 10. Dose variance tends to be in specific locations that accumulate most differences. These regions are suspect for dose accumulation errors. Despite the dose differences found, DVHs, TCP, and NTCP values varied little, indicating minimal clinical impact of DIR parameters. Conclusions: Accumulated dose variations due to DIR parameter selection occur in limited regions of an image. Such variation can be used to estimate the precision of 4D dose. Although minimal clinical impact is found for the case presented, additional study with more patients and different planning features are required prior to establishing global conclusions.Supported by NIH‐P01CA116602 and Philips Medical Systems