bluuebunny/crossref_metadata_2025_split huggingface dataset:
TU‐D‐209‐03: Alignment of the Patient Graphic Model Using Fluoroscopic Images for Skin Dose Mapping
Authors: Oines A , Oines A , Kilian‐Meneghin J , Karthikeyan B , Rudin S , Bednarek D 
Published: July 2016

Purpose:The Dose Tracking System (DTS) was developed to provide realtime feedback of skin dose and dose rate during interventional fluoroscopic procedures. A color map on a 3D graphic of the patient represents the cumulative dose distribution on the skin. Automated image correlation algorithms are described which use the fluoroscopic procedure images to align and scale the patient graphic for more accurate dose mapping.Methods:Currently, the DTS employs manual patient graphic selection and alignment. To improve the accuracy of dose mapping and automate the software, various methods are explored to extract information about the beam location and patient morphology from the procedure images. To match patient anatomy with a reference projection image, preprocessing is first used, including edge enhancement, edge detection, and contour detection. Template matching algorithms from OpenCV are then employed to find the location of the beam. Once a match is found, the reference graphic is scaled and rotated to fit the patient, using image registration correlation functions in Matlab. The algorithm runs correlation functions for all points and maps all correlation confidences to a surface map. The highest point of correlation is used for alignment and scaling. The transformation data is saved for later model scaling.Results:Anatomic recognition is used to find matching features between model and image and image registration correlation provides for alignment and scaling at any rotation angle with less than onesecond runtime, and at noise levels in excess of 150% of those found in normal procedures.Conclusion:The algorithm provides the necessary scaling and alignment tools to improve the accuracy of dose distribution mapping on the patient graphic with the DTS.Partial support from NIH Grant R01‐EB002873 and Toshiba Medical Systems Corp.
TU‐D‐207B‐06: Pathological Response Prediction by Radiomic Data From Primary and Lymph Nodes in NSCLC
Authors: Coroller T , Agrawal V , Narayan V , Lee S , Mak R , Aerts H 
Published: July 2016

Purpose:In advanced non‐small cell lung cancer (NSCLC) patient, metastasis can spread from the primary tumor to the lymph nodes and hence could have a distinct phenotype compared to unaffected nodes. In this study we investigated the complementary information of radiomics extracted from lymph nodes and the primary tumor in order to predict pathological response at time of surgery after chemoradiation in patients with stage II‐III NSCLC.Methods:86 NSCLC patients with primary tumor and involved lymph nodes (LN) were included in this study. Twenty radiomic features were selected based on stability and variance. Predictive power was evaluated using AUC and false discovery rate (FDR) corrected p‐values. Conventional imaging features (total tumor / LN volume and axial tumor diameter) and clinical characteristics were included for comparison. Classification power was investigated using random forest. Performances were assessed using cross validation (1000 iterations, 70% training / 30% validation).Results:Three radiomic features were predictive for pathologic (GRD) gross residual disease (AUC range 0.69–0.75, p<0.05) and two pathologic (pCR) complete response (AUC range 0.65–0.68, p<0.05). No conventional imaging features were predictive of either outcome (range AUC = 0.51 to 0.61, p>0.05). Patients with pCR were likely to have more homogeneous LN (large area emphasis, AUC=0.74, p<0.05) when in the other hand patients with GRD present rounder primary tumor shape (spherical disproportionality, AUC= 0.68 p<0.05). Cross validation AUC values shown that the combined radiomics‐clinical features set outperformed for each outcomes (median AUC = 0.68 and 0.74 respectively for pCR and GRD).Conclusion:We demonstrate that LN phenotypic information, ascertained from radiomic features, is complementary to imaging features obtained from the primary tumor. These features are strongly associated with response to chemoradiation as determined by pathologic response and provide greater predictive performance than clinical characteristics and conventional assessment of tumor burden by diameter or volume.R.M. have consulting interest with Amgen.
TU‐D‐PinS Room/Hall E‐01: Siemens Digital Breast Tomosynthesis: Design of a Wide Angle System & Quality Control
Authors: Klinnert T. 
Published: July 2016

This session along with the others on Digital Breast Tomosynthesis (DBT) offered at this years meeting as part of the Educational, Scientific and Partners in Solutions is intended to meet the FDA requirements for physicists to survey a DBT system. Specifically, this vendor offered session held as part of the Partners in Solutions is also meant to focus on those requirements. This session is being done along with the other two vendors of approved DBT systems in order to cover the machine specific features of those systems.

Learning Objectives:
Meet FDA requirement of introducing vendor specific features of this respective DBT system
TU‐FG‐207B‐05: Funding Opportunities at the National Science Foundation
Authors: Olbricht W. 
Published: July 2016

Up‐to‐date knowledge about federal funding opportunities related to medical physics research, as well as obtaining skills for writing effective grant proposals are critical for academic and entrepreneurial medical physicists. In this symposium, program directors from key federal research funding agencies, including the National Cancer Institute, the National Institute of Biomedical Imaging and Bioengineering, and the National Science Foundation, will present information about current funding opportunities relevant to the field of medical physics. They will also provide insight to issues that applicants should pay special attention to when crafting their research grant proposals. In addition, the symposium will include presentations on research funding for small business concerns, and the results of an independent AAPM study of the National Institutes of Health funding of AAPM members from 2002–2015.

Learning Objectives:
To learn about current federal funding initiatives relevant to medical physics research
To learn about tactics important for crafting convincing research proposals
To learn about an independent study of NIH funding of research done by AAPM membersB. Whelan, this work was commissioned and funded by the AAPM
TU‐H‐204‐02: Work of NRC, States and of re‐evaluating dose limits by NCRP
Authors: Dauer L. 
Published: July 2016

Since 1928, the International Commission on Radiological Protection (ICRP) has developed, maintained, and elaborated the International System of Radiological Protection used world‐wide as the common basis for radiological protection standards, legislation, guidelines, programs, and practice. ICRP provides and periodically revises radiation and tissue weighing factors, provides and updates recommended dose limits for occupational and public exposures, recommends dose levels for termination of pregnancy, and estimates threshold doses for tissue reactions (deterministic effects). ICRP developed the dose quantity “effective dose”.NCRP Council Committee 1 (CC‐1) is charged with developing recommendations for revising radiation protection guidance for the United States. Topics to be discussed include a summary of current ICRP guidance, NCRP CC‐1 directions, NRC regulatory changes on the horizon, and potential implications of radiation protection guidance changes on the practice of medicine. The opinions of AAPM members on potential changes are welcomed.NCRP Program Area Committee (PAC) 4 has oversight of activities in radiation protection in medicine, including protection of patients and training of health care workers. Documents have been published recently on diagnostic reference levels and achievable doses, health effects of preconception and prenatal radiation exposure, and administrative policies for quality assurance and peer review of tissue reactions associated with fluoroscopically guided interventions. Additional documents are in preparation.

Learning Objectives:
To understand the international system of radiation protection and learn about the work of the International Commission on Radiological Protection (ICRP) in relation to activities of medical physicists
To understand the ongoing work of NCRP in developing new guidance for radiation protection in the U.S.
To understand the ongoing work of NCRP in developing new recommendations for radiation protection in medicine.
To learn about other national organizations in US whose work plays a useful role in the activities of medical physicists.M. Rehani, Work done as part of being member of ICRP. ICRP is an independent charity.
TU‐H‐201‐00: New Member Symposium
Authors: Keener Justin , Johnson Amirh 
Published: July 2016

The New New Symposium is a symposium for members relatively new to the organization to learn about the organizational structure and operational procedures of the society; how decisions are made, how the council and committee leadership is appointed and operates, opportunities for volunteer involvement, and a brief overview of the services and efforts provided by the HQ staff and the website. Attendees will hear from council chairs, key staff and chairs, and members with volunteer experience.After the symposium a social hour ensues with opportunities to interact with key AAPM members. The New Member Symposium is a (free) ticket option when you register online for the Annual Meeting. And don't forget registrants receive one (free) ticket for a beverage of your choice during the social afterwards.
TU‐H‐201‐02: AAPM Overview
Authors: Miller R. 
Published: July 2016

The New New Symposium is a symposium for members relatively new to the organization to learn about the organizational structure and operational procedures of the society; how decisions are made, how the council and committee leadership is appointed and operates, opportunities for volunteer involvement, and a brief overview of the services and efforts provided by the HQ staff and the website. Attendees will hear from council chairs, key staff and chairs, and members with volunteer experience.After the symposium a social hour ensues with opportunities to interact with key AAPM members. The New Member Symposium is a (free) ticket option when you register online for the Annual Meeting. And don't forget registrants receive one (free) ticket for a beverage of your choice during the social afterwards.
TU‐H‐BRC‐07: Therapeutic Benefit in Spatially Fractionated Radiotherapy (GRID) Using Helical Tomotherapy
Authors: Narayanasamy G , Zhang X , Meigooni A , Liang X , Paudel N , Morrill S , Maraboyina S , Peacock L , Penagaricano J 
Published: July 2016

Purpose:The aim of this project is to study the therapeutic ratio (TR) for helical Tomotherapy (HT) based spatially fractionated radiotherapy (GRID). Estimation of TR was based on the linear‐quadratic cell survival model by comparing the normal cell survival in a HT GRID to that of a uniform dose delivery in an open‐field for the same tumor survival.Methods:HT GRID plan was generated using a patient specific virtual GRID block pattern of non‐divergent, cylinder shaped holes using MLCs. TR was defined as the ratio of normal tissue surviving fraction (SF) under HT GRID irradiation to an open field irradiation with an equivalent dose that result in the same tumor cell SF. The ratio was estimated from DVH data on ten patient plans with deep seated, bulky tumor approved by the treating radiation oncologist. Dependence of the TR values on radio‐sensitivity of the tumor cells and prescription dose were also analyzed.Results:The mean ± standard deviation (SD) of TR was 4.0±0.7 (range: 3.1 to 5.5) for the 10 patients with single fraction dose of 20 Gy and tumor cell SF of 0.5 at 2 Gy. In addition, mean±SD of TR = 1±0.1 and 18.0±5.1 were found for tumor with SF of 0.3 and 0.7, respectively. Reducing the prescription dose to 15 and 10 Gy lowered the TR to 2.0±0.2 and 1.2±0.04 for a tumor cell SF of 0.5 at 2 Gy. In this study, the SF of normal cells was assumed to be 0.5 at 2 Gy.Conclusion:HT GRID displayed a significant therapeutic advantage over uniform dose from an open field irradiation. TR increases with the radioresistance of the tumor cells and with prescription dose.
TU‐H‐202‐02: Applications, Validation, Clinical Endpoints and Opportunities for CT Ventilation
Authors: Vinogradskiy Y. 
Published: July 2016

CT ventilation imaging is an exciting functional imaging modality that combines four‐dimensional computed tomography (4DCT) and deformable image registration (DIR) to provide exquisite ventilation maps of the lung. CT ventilation imaging can be used for:

Functional avoidance in thoracic radiation therapy,
Imaging longitudinal changes in regional lung function for treatment assessment and adaptation,
Image‐assisted diagnosis of non‐oncologic respiratory diseases.CT ventilation imaging uses CT, a predominantly anatomic imaging modality, and through imaging processing creates functional images. CT ventilation imaging provides functional images that are higher resolution, faster and cheaper to perform than the clinical standard, SPECT. Indeed the number of CT ventilation abstracts presented at the AAPM meeting has been doubling every two years. With the world's‐first clinical trial of CT ventilation functional image‐guided radiation therapy now underway, the first dedicated scientific symposium will educate and stimulate AAPM members from both radiology and radiation oncology.This symposium will compare the foundations of CT ventilation imaging with competing MRI, PET and SPECT ventilation imaging methods, and details the first clinical trial of CT ventilation imaging for functional avoidance in lung cancer radiation therapy. The spatial‐temporal nature of pulmonary ventilation, response maps to radiation and the design of predictive models will be presented. Validation efforts and challenges will also be discussed, from clinical outcome correlations in single time point and longitudinal studies, to cross‐modality image comparisons in the first multi‐institutional CT ventilation imaging challenge.The panel will discuss the future role of CT ventilation imaging, and what level of physiologic validation is needed for applications in radiation oncology and beyond.

Learning Objectives:
Learn the principles of CT ventilation imaging and how ventilation images are acquired with MRI, PET and SPECT
Understand the methods used to benchmark CT ventilation and the correlations between CT ventilation imaging and clinical outcomes
Recognize the clinical applications of CT ventilation imaging in radiation oncology and beyondAustralian NHMRC Fellowship. Australian NSW Cancer Institute Fellowship.; Y. Vinogradskiy, The authors acknowledge NIH R01CA200817 grant and Stat of Colorado grant.; T. Yamamoto, This study was supported in part by the American Cancer Society and the Dean of the University of California Davis School of Medicine (ACS IRG‐95‐125‐13). Philips Radiation Oncology Systems loaned us a research version of the Pinnacle3 treatment planning system.; J. Bayouth, Funding support from NCIR01 CA166703; J. Kipritidis, This work has been supported by a Cancer Institute NSW Early Career Fellowship and an NHMRC Australia Fellowship.No commercial funding was received for this work.
TU‐H‐207A‐03: CT Hounsfield Unit Accuracy: Effect of Beam Hardening On Phantom and Clinical Whole‐Body CT Images
Authors: Ai H , Wendt R 
Published: July 2016

Purpose:To assess the effect of beam hardening on measured CT HU values.Methods:An anthropomorphic knee phantom was scanned with the CT component of a GE Discovery 690 PET/CT scanner (120kVp, 300mAs, 40?0.625mm collimation, pitch=0.984, FOV=500mm, matrix=512?512) with four different scan setups, each of which induces different degrees of beam hardening by introducing additional attenuation media into the field of view. Homogeneous voxels representing “soft tissue” and “bone” were segmented by HU thresholding followed by a 3D morphological erosion operation which removes the non‐homogenous voxels located on the interface of thresholded tissue mask. HU values of segmented “soft tissue” and “bone” were compared.Additionally, whole‐body CT data with coverage from the skull apex to the end of toes were retrospectively retrieved from seven PET/CT exams to evaluate the effect of beam hardening in vivo. Homogeneous bone voxels were segmented with the same method previously described. Total In‐Slice Attenuation (TISA) for each CT slice, defined as the summation of HU values over all voxels within a CT slice, was calculated for all slices of the seven whole‐body CT datasets and evaluated against the mean HU values of homogeneous bone voxels within that slice.Results:HU values measured from the phantom showed that while “soft tissue” HU values were unaffected, added attenuation within the FOV caused noticeable decreases in the measured HU values of “bone” voxels. A linear relationship was observed between bone HU and TISA for slices of the torso and legs, but not of the skull.Conclusion:Beam hardening effect is not an issue of concern for voxels with HU in the soft tissue range, but should not be neglected for bone voxels. A linear relationship exists between bone HU and the associated TISA in non‐skull CT slices, which can be exploited to develop a correction strategy.
TU‐H‐207A‐04: How Patient Positioning in CT Affects More Than the AEC: Image Noise Uniformity and CT Number Changes as a Function of Positioning
Authors: Szczykutowicz T , Duplissis A , Miller D 
Published: July 2016

Purpose:Studies dealing with patient positioning in CT have mainly dealt with dose and image noise changes. For diagnosis, only dose decreases can negatively affect the diagnostic utility of the exam via an increase in image noise. However, a little studied consequence of poor positioning is CT number and noise uniformity changes.Methods:An anthropomorphic phantom was imaged in 2 cm vertical steps between the highest and lowest couch positions. CT number and noise were measured using regions of interest (ROI) in the upper‐thorax, mid‐thorax, and abdomen. The degree of noise non‐uniformity and CT number change was assessed by comparing values obtained in the anterior vs. posterior regions. Additionally, to add clinical support for the study, we analyzed 5,746 abdominal patients at our institution and obtained their lateral and vertical mis‐positioning from iso‐center. The patients ranged in size from teens to large adults. Box and whisker plots were used to identify the range of patient poisonings seen in our clinic.Results:Absolute CT number changes between anterior and posterior ROIs over 10 HU were measured for ROIs at 4 cm off‐centering. Noise uniformity varied by greater than 2 times for all regions at an offset of −10 cm. The 25–75 percentile ranges for patient positioning was −.91 – 1.4, −.87 – .88, −1.3 – .93, −1.8 – .60 cm for pediatrics, small adults, medium adults, and large adults respectively. However, 1.4% of our patients had mis‐positioning errors outside of 4 cm.Conclusion:The CT number changes shown here are large enough to warrant further investigation on how positioning might affect clinical decision making that relies on CT number for pathology characterization, especially due to the fact our clinical positioning data demonstrates we will have HU differences on the order of 10–20 HU.Research support GE Healthcare. TPS supplies CT protocols to GE under a licensing agreement.
TU‐H‐207A‐06: The Effects of Various CT Tube Current Modulation (TCM) Schemes On Dose. Do You Really Know What Your TCM Scheme Is Doing?
Authors: Singhrao K , Bostani M , Hardy A , Cagnon C , McNitt‐Gray M 
Published: July 2016

Purpose:To compare the effects of various tube current modulation (TCM) schemes – including attenuation‐based, “organ‐based” and combined schemes ‐ on both the resulting tube current values as well as dose savings.Methods:An anthropomorphic adult thorax phantom was scanned using a Multidetector row CT scanner that offered both attenuation‐based and “organ‐based” TCM schemes that could be used separately or in combination (Definition AS64, Siemens Healthcare). A small ion chamber was attached to a medial location on the surface of the chest phantom to provide a reference value which served as proxy for organ dose. Scans were performed under each possible TCM configuration (fixed mA, attenuationbased only, organ‐based only and combined organ and attenuation based) using the same nominal parameters (e.g. Quality Reference mAs). The actual TCM scheme was extracted from the raw projection data of each scan to illustrate the actual mA variations. The scanner CTDIvol and ion chamber readings were recorded for each scan and comparisons were made across TCM schemes.Results:Each of the TCM schemes showed substantially different mA patterns. All TCM schemes showed some reduction in CTDIvol compared to a fixed mA scan with the same nominal settings; however the values ranged from a decrease of 2% (organ based only) to 18% (attenuation based only). The dose reduction to the surface dose point varied from a decrease of 34% (organ based only) to an increase of 15% (attenuation based only) compared to the fixed mA scan. Examining the actual TCM schemes from the raw data files allows us to understand the effects of each scheme.Conclusion:Phantom scans allowed us to compare the effects of different TCM schemes on both CTDIvol values as well as point doses. Future work will focus on organ doses from each scheme using validated Monte Carlo techniques.
TU‐H‐206‐06: B1 Inhomogeneity Correction for Measuring T1 From DCE MRI
Authors: Gach H , Mason N , Wang H , Tsien C , Benzinger T , Robinson C 
Published: July 2016

Purpose:3D MRI sequences typically used in DCE MRI suffer from B1 inhomogeneities associated with the slab‐selective RF pulse. B1 inhomogeneities affect the calculation of tissue T1 often used to solve the two‐compartment model. Previously, the inhomogeneities were corrected based on Bloch equation simulations of the RF pulse. However, the RF pulse specification may not be readily available or the simulation may not represent the actual scan conditions. The objective of this work was to directly measure B1 inhomogeneities and apply an inhomogeneity correction to minimize quantification errors in T1 fitting.Methods:We used a 3D GRE sequence with varied flip angles (2–30°) to measure T1‐weighted signals in phantoms at 3 T on a Siemens mMR. 2D EPI B1 maps were acquired to measure the B1 inhomogeneity associated with the RF coils. Inversion recovery T1 maps were acquired for ground truth. Two B1 inhomogeneity correction methods were compared: 1) A 3D segmented EPI sequence measured the RF slab selective excitation profile; and 2) The T1's of phantom standards were used to normalize the 3D GRE images.Results:Only the central 1/3 of the 3D GRE slices yielded accurate T1 values without correction. The slice profiles measured with 3D EPI were consistent between measurements made with different flip angles. The two correction approaches resulted in similar T1 values for at least 2/3 of the slices. Approach 2 yielded more slices with values comparable to the ground truth. However, Approach 1 resulted in less error than Approach 2 for the upper 2/3 of the slices.Conclusion:Using a phantom standard with a short T1 allowed us to shorten the acquisition time of the 3D EPI sequence to less than 1 minute or increase spatial resolution. The B1 inhomogeneity correction technique requires further testing in vivo for DCE MRI studies.