bluuebunny/crossref_metadata_2025_split huggingface dataset:
SU‐E‐I‐85: Exploring the 18F‐Fluorodeoxyglucose PET Characteristics in Staging of Esophageal Squamous Cell Carcinoma
Authors: Ma C , Yin Y 
Published: July 2014

Purpose:The aim of this study was to explore the characteristics derived from 18F‐fluorodeoxyglucose (18F‐FDG) PET image and assess its capacity in staging of esophageal squamous cell carcinoma (ESCC).Methods:26 patients with newly diagnosed ESCC who underwent 18F‐FDG PET scan were included in this study. Different image‐derived indices including the standardized uptake value (SUV), gross tumor length, texture features and shape feature were considered. Taken the histopathologic examination as the gold standard, the extracted capacities of indices in staging of ESCC were assessed by Kruskal‐Wallis test and Mann‐Whitney test. Specificity and sensitivity for each of the studied parameters were derived using receiver‐operating characteristic curves.Results:18F‐FDG SUVmax and SUVmean showed statistically significant capability in AJCC and TNM stages. Texture features such as ENT and CORR were significant factors for N stages(p=0.040, p=0.029). Both FDG PET Longitudinal length and shape feature Eccentricity (EC) (p≤0.010) provided powerful stratification in the primary ESCC AJCC and TNM stages than SUV and texture features. Receiver‐operating‐characteristic curve analysis showed that tumor textural analysis can capabilty M stages with higher sensitivity than SUV measurement but lower in T and N stages.Conclusion:The 18F‐FDG image‐derived characteristics of SUV, textural features and shape feature allow for good stratification AJCC and TNM stage in ESCC patients.
SU‐E‐I‐95: Personalized Radiography Technical Parameters for Each Patient and Exam
Authors: Soares F , Camozzato T , Kahl G , Soares A , Zottis A 
Published: July 2014

Purpose:To determine exact electrical parameters (kV, mAs) a radiological technologist shall use taking account the exam and patient's structure, with guarantee of minimum dose and adequate quality image.Methods:A patient's absorbed dose equation was developed by means of Entrance Skin Dose (ESD), irradiated area and patient width for specific anatomy. ESD is calculated from a developed equation, where entrance surface air‐KERMA and backscatter factor are included, with air‐to‐skin coefficient conversion. We developed specific Lambert‐Beer attenuation equations derived from mass energy‐absorption coefficients data for skin, fat, and muscle and bone as one tissue. Anatomy tissue thickness distribution at central X‐ray location in anteroposterior incidence for hand and chest, was estimate by discounting constant skin and bone thickness from patient measured width, assuming the result as muscle and fat. A clinical research at a big hospital were executed when real parameters (kV, mAs, filtration, ripple) used by technologists were combined with the image quality and patient's data: anatomy width, height and weight. A correlation among the best images acquired and electrical parameters used were confronted with patient's data and dose estimation. The best combinations were used as gold standards.Results:For each anatomy, two equations were developed to calculate voltage (kV) and exposure (mAs) to reproduce and interpolate the gold standards. Patient is measured and data are input into equations, giving radiological technologists the right set of electrical parameters for that specific exam.Conclusion:This work indicates that radiological technologist can personalize the exact electrical parameters for each patient exam, instead of using standard values. It also guarantee that patients under or over‐sized measures will receive the right dose for the best image. It will stop wrong empiric adjusts technologists do when examining a non‐standard patient and reduce probability of radiography retaken because of over or under exposition.
SU‐E‐I‐100: Heterogeneity Studying for Primary and Lymphoma Tumors by Using Multi‐Scale Image Texture Analysis with PET‐CT Images
Authors: Li Dengwang , Wang Qinfen , Li H , Chen J 
Published: July 2014

Purpose:The purpose of this research is studying tumor heterogeneity of the primary and lymphoma by using multi‐scale texture analysis with PET‐CT images, where the tumor heterogeneity is expressed by texture features.Methods:Datasets were collected from 12 lung cancer patients, and both of primary and lymphoma tumors were detected with all these patients. All patients underwent whole‐body 18F‐FDG PET/CT scan before treatment. The regions of interest (ROI) of primary and lymphoma tumor were contoured by experienced clinical doctors. Then the ROI of primary and lymphoma tumor is extracted automatically by using Matlab software. According to the geometry size of contour structure, the images of tumor are decomposed by multi‐scale method.Wavelet transform was performed on ROI structures within images by L layers sampling, and then wavelet sub‐bands which have the same size of the original image are obtained. The number of sub‐bands is 3L+1. The gray level co‐occurrence matrix (GLCM) is calculated within different sub‐bands, thenenergy, inertia, correlation and gray in‐homogeneity were extracted from GLCM.Finally, heterogeneity statistical analysis was studied for primary and lymphoma tumor using the texture features.Results:Energy, inertia, correlation and gray in‐homogeneity are calculated with our experiments for heterogeneity statistical analysis.Energy for primary and lymphomatumor is equal with the same patient, while gray in‐homogeneity and inertia of primaryare 2.59595±0.00855, 0.6439±0.0007 respectively. Gray in‐homogeneity and inertia of lymphoma are 2.60115±0.00635, 0.64435±0.00055 respectively. The experiments showed that the volume of lymphoma is smaller than primary tumor, but thegray in‐homogeneity and inertia were higher than primary tumor with the same patient, and the correlation with lymphoma tumors is zero, while the correlation with primary tumor isslightly strong.Conclusion:This studying showed that there were effective heterogeneity differences between primary and lymphoma tumor by multi‐scale image texture analysis.This work is supported by National Natural Science Foundation of China (No. 61201441), Research Fund for Excellent Young and Middle‐aged Scientists of Shandong Province (No. BS2012DX038), Project of Shandong Province Higher Educational Science and Technology Program (No. J12LN23), Jinan youth science and technology star (No.20120109)
SU‐E‐I‐101: Effects of Gantry Rotation Time On CT Number Accuracy in Single‐Source Dual Energy CT Imaging with Fast‐KVp Switching
Authors: Liu X , Cody D , Rong J 
Published: July 2014

Purpose:To investigate the effects of gantry rotation time on CT number accuracy in dual energy CT imaging with GE Discovery CT750 HD singlesource CT scanner.Methods:The CT number linearity section (CTP404) of the Catphan 600 phantom was imaged using the dual energy protocols equipped on a GE Discovery CT750 HD CT scanner. The imaging section of the Catphan phantom was surrounded with a fat‐equivalent oval ring to better approximate an adult body shape during the image acquisition. A series of dual energy (gemstone spectral imaging (GSI)) presets was selected to acquire images at a gantry rotation time of 0.5 – 1.0 second in an increment of 0.1 second. Images were reconstructed using “Standard” algorithm at different monochromatic energies of 40 — 140 keV in an increment of 10 keV. Two sets of phantom image were acquired with the Axial mode and 5 mm slice thickness for each GSI preset. Total eight images were averaged to compute the CT number of each material insert in the CTP404 section. A squared region‐of‐interest (ROI) of approximate 5 x 5 mm was placed at the center of each material insert to measure the CT number and to investigate the effects of gantry rotation time on CT number accuracy.Results:For LDPE (−100 HU), the CT number increases with rotation time and starts to decrease at 0.9 s for energies at 80 keV and above; while the CT number decreases with rotation time and starts to increase at 0.8 s for energies at 60 keV and below. For Teflon (990 HU), CT number increases with rotation time and starts to decrease at 0.8 s for energies at 80 keV and above; while the CT number decreases with rotation time and starts to increase at 1.0 s for energies at 60 keV and below. At 50 keV, the average CT numbers were −101 HU and 940 HU with maximum differences of 8.7 HU and 10.7 HU for LDPE and Teflon, respectively. The CT numbers were measured −57 HU for LDPE and 913 HU for Teflon for single energy imaging at 120 kVp.Conclusion:Effects of gantry rotation time on CT number accuracy in dual energy CT imaging depends on type of insert material and the monochromatic energy at which the images were reconstructed.
SU‐E‐J‐01: 3D Fluoroscopic Image Estimation From Patient‐Specific 4DCBCT‐Based Motion Models
Authors: Dhou S , Hurwitz M , Mishra P , Lewis J 
Published: July 2014

Purpose:3D motion modeling derived from 4DCT images, taken days or weeks before treatment, cannot reliably represent patient anatomy on the day of treatment. We develop a method to generate motion models based on 4DCBCT acquired at the time of treatment, and apply the model to estimate 3D time‐varying images (referred to as 3D fluoroscopic images).Methods:Motion models are derived through deformable registration between each 4DCBCT phase, and principal component analysis (PCA) on the resulting displacement vector fields. 3D fluoroscopic images are estimated based on cone‐beam projections simulating kV treatment imaging. PCA coefficients are optimized iteratively through comparison of these cone‐beam projections and projections estimated based on the motion model. Digital phantoms reproducing ten patient motion trajectories, and a physical phantom with regular and irregular motion derived from measured patient trajectories, are used to evaluate the method in terms of tumor localization, and the global voxel intensity difference compared to ground truth.Results:Experiments included: 1) assuming no anatomic or positioning changes between 4DCT and treatment time; and 2) simulating positioning and tumor baseline shifts at the time of treatment compared to 4DCT acquisition. 4DCBCT were reconstructed from the anatomy as seen at treatment time. In case 1) the tumor localization error and the intensity differences in ten patient were smaller using 4DCT‐based motion model, possible due to superior image quality. In case 2) the tumor localization error and intensity differences were 2.85 and 0.15 respectively, using 4DCT‐based motion models, and 1.17 and 0.10 using 4DCBCT‐based models. 4DCBCT performed better due to its ability to reproduce daily anatomical changes.Conclusion:The study showed an advantage of 4DCBCT‐based motion models in the context of 3D fluoroscopic images estimation. Positioning and tumor baseline shift uncertainties were mitigated by the 4DCBCT‐based motion models, while they caused errors when using 4DCT‐based motion models.Partially funded by Varian research grant.
SU‐E‐J‐02: 4D Digital Tomosynthesis Based On Algebraic Image Reconstruction and Total‐Variation Minimization for the Improvement of Image Quality
Authors: Kim D , Kang S , Kim T , Kim S , Suh T 
Published: July 2014

Purpose:In this paper, we implemented the four‐dimensional (4D) digital tomosynthesis (DTS) imaging based on algebraic image reconstruction technique and total‐variation minimization method in order to compensate the undersampled projection data and improve the image quality.Methods:The projection data were acquired as supposed the cone‐beam computed tomography system in linear accelerator by the Monte Carlo simulation and the in‐house 4D digital phantom generation program. We performed 4D DTS based upon simultaneous algebraic reconstruction technique (SART) among the iterative image reconstruction technique and total‐variation minimization method (TVMM). To verify the effectiveness of this reconstruction algorithm, we performed systematic simulation studies to investigate the imaging performance.Results:The 4D DTS algorithm based upon the SART and TVMM seems to give better results than that based upon the existing method, or filtered‐backprojection.Conclusion:The advanced image reconstruction algorithm for the 4D DTS would be useful to validate each intra‐fraction motion during radiation therapy. In addition, it will be possible to give advantage to real‐time imaging for the adaptive radiation therapy.This research was supported by Leading Foreign Research Institute Recruitment Program (Grant No.2009‐00420) and Basic Atomic Energy Research Institute (BAERI); (Grant No. 2009‐0078390) through the National Research Foundation of Korea(NRF) funded by the Ministry of Science, ICT & Future Planning (MSIP).
SU‐E‐J‐03: A Comprehensive Comparison Between Alpha and Beta Emitters for Cancer Radioimmunotherapy
Authors: Huang C.Y. , Guatelli S , Oborn B , Allen B 
Published: July 2014

Purpose:The purpose of this study is to perform a comprehensive comparison of the therapeutic efficacy and cytotoxicity of alpha and beta emitters for Radioimmunotherapy (RIT). For each stage of cancer development, specific models were built for the separate objectives of RIT to be addressed:a) kill isolated cancer cells in transit in the lymphatic and vascular circulation,b) regress avascular cell clusters,c) regress tumor vasculature and tumors.Methods:Because of the nature of short range, high LET alpha and long energy beta radiation and heterogeneous antigen expression among cancer cells, the microdosimetric approach is essential for the RIT assessment. Geant4 based microdosimetric models are developed for the three different stages of cancer progression: cancer cells, cell clusters and tumors. The energy deposition, specific energy resulted from different source distribution in the three models was calculated separately for 4 alpha emitting radioisotopes (211At, 213Bi, 223Ra and 225Ac) and 6 beta emitters (32P, 33P, 67Cu, 90Y, 131I and 177Lu). The cell survival, therapeutic efficacy and cytotoxicity are determined and compared between alpha and beta emitters.Results:We show that internal targeted alpha radiation has advantages over beta radiation for killing isolated cancer cells, regressing small cell clusters and also solid tumors. Alpha particles have much higher dose specificity and potency than beta particles. They can deposit 3 logs more dose than beta emitters to single cells and solid tumor. Tumor control probability relies on deep penetration of radioisotopes to cancer cell clusters and solid tumors.Conclusion:The results of this study provide a quantitative understanding of the efficacy and cytotoxicity of RIT for each stage of cancer development.
SU‐E‐J‐04: A Data‐Driven, Response‐Based, Multi‐Criteria Decision Support System for Personalized Lung Radiation Treatment Planning
Authors: Luo Y , McShan D , Schipper M , Matuszak M , Kong F , Ten Haken R 
Published: July 2014

Purpose:To develop a decision support tool to predict a patient's potential overall survival (OS) and radiation induced toxicity (RIT) based on clinical factors and responses during the course of radiotherapy, and suggest appropriate radiation dose adjustments to improve therapeutic effect.Methods:Important relationships between a patient's basic information and their clinical features before and during the radiation treatment are identified from historical clinical data by using statistical learning and data mining approaches. During each treatment period, a data analysis (DA) module predicts radiotherapy features such as time to local progression (TTLP), time to distant metastases (TTDM), radiation toxicity to different organs, etc., under possible future treatment plans based on patient specifics or responses. An information fusion (IF) module estimates intervals for a patient's OS and the probabilities of RIT from a treatment plan by integrating the outcomes of module DA. A decision making (DM) module calculates “satisfaction” with the predicted radiation outcome based on trade‐offs between OS and RIT, and finds the best treatment plan for the next time period via multi‐criteria optimization.Results:Using physical and biological data from 130 lung cancer patients as our test bed, we were able to train and implement the 3 modules of our decision support tool. Examples demonstrate how it can help predict a new patient's potential OS and RIT with different radiation dose plans along with how these combinations change with dose, thus presenting a range of satisfaction/utility for use in individualized decision support.Conclusion:Although the decision support tool is currently developed from a small patient sample size, it shows the potential for the improvement of each patient's satisfaction in personalized radiation therapy. The radiation treatment outcome prediction and decision making model needs to be evaluated with more patients and demonstrated for use in radiation treatments for other cancers.P01‐CA59827;R01CA142840
SU‐E‐J‐09: A Monte Carlo Analysis of the Relationship Between Cherenkov Light Emission and Dose for Electrons, Protons, and X‐Ray Photons
Authors: Glaser A , Zhang R , Gladstone D , Pogue B 
Published: July 2014

Purpose:A number of recent studies have proposed that light emitted by the Cherenkov effect may be used for a number of radiation therapy dosimetry applications. Here we investigate the fundamental nature and accuracy of the technique for the first time by using a theoretical and Monte Carlo based analysis.Methods:Using the GEANT4 architecture for medically‐oriented simulations (GAMOS) and BEAMnrc for phase space file generation, the light yield, material variability, field size and energy dependence, and overall agreement between the Cherenkov light emission and dose deposition for electron, proton, and flattened, unflattened, and parallel opposed x‐ray photon beams was explored.Results:Due to the exponential attenuation of x‐ray photons, Cherenkov light emission and dose deposition were identical for monoenergetic pencil beams. However, polyenergetic beams exhibited errors with depth due to beam hardening, with the error being inversely related to beam energy. For finite field sizes, the error with depth was inversely proportional to field size, and lateral errors in the umbra were greater for larger field sizes. For opposed beams, the technique was most accurate due to an averaging out of beam hardening in a single beam. The technique was found to be not suitable for measuring electron beams, except for relative dosimetry of a plane at a single depth. Due to a lack of light emission, the technique was found to be unsuitable for proton beams.Co nclusions:The results from this exploratory study suggest that optical dosimetry by the Cherenkov effect may be most applicable to near monoenergetic x‐ray photon beams (e.g. Co‐60), dynamic IMRT and VMAT plans, as well as narrow beams used for SRT and SRS. For electron beams, the technique would be best suited for superficial dosimetry, and for protons the technique is not applicable due to a lack of light emission.NIH R01CA109558 and R21EB017559.
SU‐E‐J‐11: A New Optical Method to Register Patient External Motion
Authors: Barbes B , Foronda J , Azcona J , Moreno M , Prieto E , Burguete J 
Published: July 2014

Purpose:To devise and implement a new system to measure and register the patient motion during radiotherapy treatments.Methods:The system can obtain the position of several points in the 3D‐space, through their projections in the 2D‐images recorded by two cameras. The algorithm needs a series of constants, that are obtained using the images of a calibrated phantom. To test the system, some adhesive labels were placed on the surface of an object. Two cameras recorded the moving object over time. An in‐house developed software localized the labels in each image. In the first pair of images, the program used a first approximation given by the user. In the subsequent images, it used the last position as an approximate location. The final exact coordinates of the point were obtained in a two‐step process using the contrast of the images. From the 2D‐positions of the point in each frame, the 3D‐trajectories of each of these marks were obtained. The system was tested with linear displacements, oscillations of a mechanical oscillator, circular trajectories of a rotating disk, and with respiratory motion of a volunteer.Results:Trajectories of several points were reproduced with sub‐millimeter accuracy in the three directions of the space. The system was able to follow periodic motion with amplitudes lower than 0.5mm; and trajectories of rotating points at speeds up to 200mm/s. The software could also track accurately the respiration motion of a person.Conclusion:A new, inexpensive optical tracking system for patient motion has been demonstrated. The system detects motion with high accuracy. Installation and calibration of the system is simple and quick. Data collection is not expected to involve any discomfort for the patient, nor any delay for the treatment. The system could be also used as a method of warning for patient movements, and for gating.We acknowledge financial support from Fundacion Mutua Madrilena, Madrid, Spain.
SU‐E‐J‐16: A Review of the Magnitude of Patient Imaging Shifts in Relation to Departmental Policy Changes
Authors: O' Connor M , Sansourekidou P 
Published: July 2014

Purpose:To evaluate how changes in imaging policy affect the magnitude of shifts applied to patients.Methods:In June 2012, the department's imaging policy was altered to require that any shifts derived from imaging throughout the course of treatment shall be considered systematic only after they were validated with two data points that are consistent in the same direction. Multiple additions and clarifications to the imaging policy were implemented throughout the course of the data collection, but they were mostly of administrative nature. Entered shifts were documented in MOSAIQ (Elekta AB) through the localization offset. The MOSAIQ database was queried to identify a possible trend. A total of 25,670 entries were analyzed, including four linear accelerators with a combination of MV planar, kV planar and kV three dimensional imaging. The monthly average of the magnitude of the vector was used. Plan relative offsets were excluded. During the evaluated period of time, one of the satellite facilities acquired and implemented Vision RT (AlignRT Inc).Results:After the new policy was implemented the shifts variance and standard deviation decreased. The decrease is linear with time elapsed. Vision RT implementation at one satellite facility reduced the number of overall shifts, specifically for breast patients.Conclusion:Changes in imaging policy have a significant effect on the magnitude of shifts applied to patients. Using two statistical points before applying a shift as persistent decreased the overall magnitude of the shifts applied to patients.