bluuebunny/crossref_metadata_2025_split huggingface dataset:
SU‐E‐I‐97: Smart Auto‐Planning Framework in An EMR Environment (SAFEE)
Authors: Zhang B , Chen S , Mutaf Y , Prado K , D' Souza W 
Published: July 2014

Purpose:Our Radiation Oncology Department uses clinical practice guidelines for patient treatment, including normal tissue sparing and other dosimetric constraints. These practice guidelines were adapted from national guidelines, clinical trials, literature reviews, and practitioner's own experience. Modern treatment planning systems (TPS) have the capability of incorporating these practice guidelines to automatically create radiation therapy treatment plans with little human intervention. We are developing a software infrastructure to integrate clinical practice guidelines and radiation oncology electronic medical record (EMR) system into radiation therapy treatment planning system (TPS) for auto planning.Methods:Our Smart Auto‐Planning Framework in an EMR environment (SAFEE) uses a software pipeline framework to integrate practice guidelines,EMR, and TPS together. The SAFEE system starts with retrieving diagnosis information and physician's prescription from the EMR system. After approval of contouring, SAFEE will automatically create plans according to our guidelines. Based on clinical objectives, SAFEE will automatically select treatment delivery techniques (such as, 3DRT/IMRT/VMAT) and optimize plans. When necessary, SAFEE will create multiple treatment plans with different combinations of parameters. SAFEE's pipeline structure makes it very flexible to integrate various techniques, such as, Model‐Base Segmentation (MBS) and plan optimization algorithms, e.g., Multi‐Criteria Optimization (MCO). In addition, SAFEE uses machine learning, data mining techniques, and an integrated database to create clinical knowledgebase and then answer clinical questions, such as, how to score plan quality or how volume overlap affects physicians' decision in beam and treatment technique selection.Results:In our institution, we use Varian Aria EMR system and RayStation TPS from RaySearch, whose ScriptService API allows control by external programs. These applications are the building blocks of our SAFEE system.Conclusion:SAFEE is a feasible method of integrating clinical information to develop an auto‐planning paradigm to improve clinical workflow in cancer patient care.
SU‐E‐J‐05: A Dose‐Based Metric to Assess the Accuracy of Deformable Image Registration
Authors: Annis S , Heath E 
Published: July 2014

Purpose:To examine the correlation between landmark‐based spatial registration error and a novel metric for evaluating dose mapping error.Methods:The dose mapping error was calculated from the difference between the dose distributions obtained using two different dose mapping techniques. One method calculates the dose on a deformed geometry while the other calculates the dose on the target geometry. In both cases the dose distributions are mapped in a consistent manner back to the reference geometry. For a realistic clinical lung plan, dose distributions were mapped to the Exhale phase for repeated deformable registrations with different average spatial registration accuracies as determined by distance to agreement of 300 manually identified landmarks. The dose mapping error and spatial registration error were compared at each landmark and the correlation was assessed.Results:No clear correlation was observed between spatial registration accuracy and dose mapping error, however, the average dose mapping error was found to increase as average spatial registration accuracy increased. The relationship between the dose mapping error and spatial error at each landmark point was found to be influenced by the dose gradient, density gradients and voxel size.Conclusion:The dose mapping error was found to not have any direct relationship with spatial registration error but depends on a number of factors including: dose gradient, density gradient and voxel size. Our results indicate that landmark analysis on its own is not a sufficient predictor of the accuracy of dose mapping and that metrics that directly assess the dose mapping error should be used.Natural Sciences and Engineering Research Council
SU‐E‐J‐06: A Feasibility Study On Clinical Implementation of 4D‐CBCT in Lung Cancer Treatment
Authors: Hu Y , Ruan C , Stanford J , Duggar W , Rajaguru P , He R , Yang C 
Published: July 2014

Purpose:Four‐dimensional cone‐beam CT (4D‐CBCT) is a novel imaging technique to setup patients with pulmonary lesions in radiation therapy. This paper is to perform a feasibility study on the implementation of 4D‐CBCT as image guidance for (1) SBRT and (2) Low Modulation (Low‐Mod) IMRT in lung cancer treatment.Methods:Image artifacts and observers variability are evaluated by analyzing the 4D‐CT QA phantom and patient 4D image data. There are two 4D‐CBCT image artifacts: (1) Spatial artifact caused by the patient irregular breathing pattern will generate blurring and anatomy gap/overlap; (2) Cone beam scattering and hardening artifact will affect the image spatial and contrast resolution. The couch shift varies between 1mm to 3mm from different observers during the 4D‐CBCT registration. Breath training is highly recommended to improve the respiratory regularity during CT simulation and treatment, especially for SBRT. Elekta XVI 4.5 Symmetry protocol is adopted in the patient 4DCBCT scanning and intensity‐based registration. Physician adjustments on the auto‐registration are involved prior to the treatment. Physician peer review on 4D‐CBCT image acquisition and registration is also recommended to reduce the inter‐observer variability. The average 4D‐CT in reference volume coordinates is exported to MIM Vista 5.6.2 to manually fuse to the planning CT for further evaluation.Results:(1) SBRT: 4DCBCT is performed in dry‐run and in each treatment fraction. Image registration and couch shift are reviewed by another physician on the 1st fraction before the treatment starts. (2) Low‐Mod IMRT: 4D‐CBCT is performed and peer reviewed on weekly basis.Conclusion:4D‐CBCT in SBRT dry‐run can discover the ITV discrepancies caused by the low quality 4D‐CT simulation. 4D‐CBCT during SBRT and Low‐Mod IMRT treatment provides physicians more confidence to target lung tumor and capability to evaluate inter‐fractional ITV changes. More advanced 4D‐CBCT scan protocol and reconstruction algorithm may be needed in the future.
SU‐E‐J‐10: A Moving‐Blocker‐Based Strategy for Simultaneous Megavoltage and Kilovoltage Scatter Correction in Cone‐Beam Computed Tomography Image Acquired During Volumetric Modulated Arc Therapy
Authors: Ouyang L , Lee H , Wang J 
Published: July 2014

Purpose:To evaluate a moving‐blocker‐based approach in estimating and correcting megavoltage (MV) and kilovoltage (kV) scatter contamination in kV cone‐beam computed tomography (CBCT) acquired during volumetric modulated arc therapy (VMAT).Methods:XML code was generated to enable concurrent CBCT acquisition and VMAT delivery in Varian TrueBeam developer mode. A physical attenuator (i.e., “blocker”) consisting of equal spaced lead strips (3.2mm strip width and 3.2mm gap in between) was mounted between the x‐ray source and patient at a source to blocker distance of 232mm. The blocker was simulated to be moving back and forth along the gantry rotation axis during the CBCT acquisition. Both MV and kV scatter signal were estimated simultaneously from the blocked regions of the imaging panel, and interpolated into the un‐blocked regions. Scatter corrected CBCT was then reconstructed from un‐blocked projections after scatter subtraction using an iterative image reconstruction algorithm based on constraint optimization. Experimental studies were performed on a Catphan 600 phantom and an anthropomorphic pelvis phantom to demonstrate the feasibility of using moving blocker for MV‐kV scatter correction.Results:MV scatter greatly degrades the CBCT image quality by increasing the CT number inaccuracy and decreasing the image contrast, in addition to the shading artifacts caused by kV scatter. The artifacts were substantially reduced in the moving blocker corrected CBCT images in both Catphan and pelvis phantoms. Quantitatively, CT number error in selected regions of interest reduced from 377 in the kV‐MV contaminated CBCT image to 38 for the Catphan phantom.Conclusions:The moving‐blockerbased strategy can successfully correct MV and kV scatter simultaneously in CBCT projection data acquired with concurrent VMAT delivery.This work was supported in part by a grant from the Cancer Prevention and Research Institute of Texas (RP130109) and a grant from the American Cancer Society (RSG‐13‐326‐01‐CCE).
SU‐E‐J‐12: A New Stereological Method for Tumor Volume Evaluation for Esophageal Cancer
Authors: Feng Y , Pan R , Wang P , Yang C , Lin W , Sa Y 
Published: July 2014

Purpose:Stereological method used to obtain three dimensional quantitative information from two dimensional images is a widely used tool in the study of cells and pathology. But the feasibility of the method for quantitative evaluation of volumes with 3D image data sets for radiotherapy clinical application has not been explored. On the other hand, a quick, easy‐to‐use and reliable method is highly desired in image‐guided‐radiotherapy(IGRT) for tumor volume measurement for the assessment of response to treatment. To meet this need, a stereological method for evaluating tumor volumes for esophageal cancer is presented in this abstract.Methods:The stereology method was optimized by selecting the appropriate grid point distances and sample types. 7 patients with esophageal cancer were selected retrospectively for this study, each having pre and post treatment computed tomography (CT) scans. Stereological measurements were performed for evaluating the gross tumor volume (GTV) changes after radiotherapy and the results was compared with the ones by planimetric measurements. Two independent observers evaluated the reproducibility for volume measurement using the new stereological technique.Results:The intraobserver variation in the GTV volume estimation was 3.42±1.68cm3 (the Wilcoxon matched‐pairs test Resultwas Z=−1.726,P=0.084>0.05); the interobserver variation in the GTV volume estimation was 22.40±7.23 cm3 (Z=−3.296,P=0.083>0.05), which showed the consistency in GTV volume calculation with the new method for the same and different users. The agreement level between the results from the two techniques was also evaluated. Difference between the measured GTVs was 20.10±5.35 cm3 (Z=−3.101,P=0.089>0.05). Variation of the measurement results using the two techniques was low and clinically acceptable.Conclusion:The good agreement between stereological and planimetric techniques proves the reliability of the stereological tumor volume estimations. The optimized stereological technique described in this abstract may provide a quick, unbiased and reproducible tool for tumor volume estimation for treatment response assessment.Supported by NSFC (#81041107, #81171342 and #31000784)
SU‐E‐J‐14: A Novel Approach to Evaluate the Dosimetric Effect of Rectal Variation During Image Guided Prostate Radiotherapy
Authors: Murray J , McQuaid D , Dunlop A , Buettner F , Nill S , Hall E , Dearnaley D , Gulliford S 
Published: July 2014

Purpose:Deformable registration establishes the spatial correspondence back to the reference image in order to accumulate dose. However, in prostate radiotherapy the changing shape and volume of the rectum present a challenge to accurate deformable registration and consequently calculation of delivered dose. We explored an alternative approach to calculating accumulated dose to the rectum, independent of deformable registration.Methods:This study was performed on three patients who received online image‐guided radiotherapy (IGRT) with daily CBCT (XVI‐system,Elekta) and target localization using intraprostatic fiducials. On each CBCT, the rectum was manually contoured and bulk density assignments were made allowing dose to be calculated for each fraction. Dose‐surface maps (DSM) were generated (MATLAB,Mathworks,Natick,MA) by considering the rectum as a cylinder and sampling the dose at 21‐equispaced points on each CT slice. The cylinder was “cut” at the posterior‐most position on each CT and unfolded to generate a DSM. These were normalised in the longitudinal direction by interpolation creating maps of 21×21 pixels. A DSM was produced for each CBCT and the dose was accumulated.Results:The mean accumulated delivered rectal surface dose was on average 7.5(+/−3.5)% lower than the planned dose. The dose difference maps consistently show that the greatest variation in dose between planned and delivered dose is away from where the rectal surface is adjacent to the prostate.Conclusion:Estimation of dose accumulation using DSM provides an alternative method for determining actual delivered dose to the rectum. The dose difference is greatest in areas away from the region where the rectal surface abuts the prostate, the region where set‐up is verified. The change in size and shape of the rectum was shown to resultin a change in the accumulated dose compared to the planned dose and this will have an impact on determining the relationships between dose delivered and toxicity. We acknowledge funding from CRUK and acknowledge NHS funding to the NIHR Biomedical Research Centre for Cancer.Patients were treated within the CHHiP IGRT sub‐study (CRUK/06/016, ISRCTN:97182923) funded by CRUK. RayStation was used under an evaluation agreement with RaySearch Laboratories AB.
SU‐E‐J‐20: Adaptive Aperture Morphing for Online Correction for Prostate Cancer Radiotherapy
Authors: Sandhu R , Qin A , Yan D 
Published: July 2014

Purpose:Online adaptive aperture morphing is desirable over translational couch shifts to accommodate not only the target position variation but also anatomic changes (rotation, deformation, and relation of target to organ‐atrisks). We proposed quick and reliable method for adapting segment aperture leaves for IMRT treatment of prostate.Methods:The proposed method consists of following steps: (1) delineate the contours of prostate, SV, bladder and rectum on kV‐CBCT; (2) determine prostate displacement from the rigid body registration of the contoured prostate manifested on the reference CT and the CBCT; (3) adapt the MLC segment apertures obtained from the pre‐treatment IMRT planning to accommodate the shifts as well as anatomic changes. The MLC aperture adaptive algorithm involves two steps; first move the whole aperture according to prostate translational/rotational shifts, and secondly fine‐tune the aperture shape to maintain the spatial relationship between the planning target contour and the MLC aperture to the daily target contour. Feasibility of this method was evaluated retrospectively on a seven‐field IMRT treatment of prostate cancer patient by comparing dose volume histograms of the original plan and the aperture‐adjusted plan, with/without additional segments weight optimization (SWO), on two daily treatment CBCTs selected with relative large motion and rotation.Results:For first daily treatment, the prostate rotation was significant (12degree around lateral‐axis). With apertureadjusted plan, the D95 to the target was improved 25% and rectum dose (D30, D40) was reduced 20% relative to original plan on daily volumes. For second treatment‐fraction, (lateral shift = 6.7mm), after adjustment target D95 improved by 3% and bladder dose (D30, maximum dose) was reduced by 1%. For both cases, extra SWO did not provide significant improvement.Conclusion:The proposed method of adapting segment apertures is promising in treatment position correction, including target translational displacement, rotation and deformation. Additional SWO could improve ROIs dose distribution.
SU‐E‐J‐21: Advantages of Ultra Fast Radiation Dose Delivering
Authors: Feng Y 
Published: July 2014

Purpose:For delivering conformed dose to a moving tumor and sparing normal tissue, we presented an innovation that was combined a linear accelerator and a storage ring to generate ultra high dose rate. This innovation allows delivering prescribed dose to a moving target in such a short time period, for an example 0.1 second, during which the displacement of the target could be ignored.Methods:The advantages of this approach were evaluated based on normal tissue sparing, feasibility, accuracy, and time saving in clinical treatment. The target volume reduction with this innovation approach was demonstrated by analyzing the values of GTVs, ITVs, and PTVs obtained from 15 patients who had been diagnosed with malignant neoplasm of lung and treated with SBRT. The processes of SBRT treatment were investigated and advantages of this innovation in improving SBRT lung treatment were evaluated.Results:With the ultra‐high dose rate, the target volumes could be reduced by ∼30% to 50%. The innovation combining with IGRT technique could deliver prescribed dose to moving target accurately with simpler procedures than that of adaptive approach. This new approach could reduce the time of guiding treatment by many times. The new technique make a new strategy became feasible that was to deliver the dose to a target when it moved to a desirable location, such as away from critical organs.Conclusion:Combining with IGRT technique, this innovation could significantly improve the accuracy to deliver dose to moving targets with a shorter time than conventional techniques. The innovation opens a door for new strategies to deliver dose to moving targets.
SU‐E‐J‐26: Analysis of Image Quality in CBCT QA Using a Treatment Planning System
Authors: Xu M 
Published: July 2014

Purpose:The objective of this study is to propose an alternative QA technique that analyzes imaging quality(IQ) in CBCT‐QA processing.Methods:A catphan phantom was used to take CT imaging data set that were imported into a treatment planning system – Eclipse. The image quality was analyzed in terms of in‐slice geometry resolution, Hounsfield numbers(HU) accuracy, mean‐slice thickness, edge‐to‐center uniformity, low contrast resolution, and high contrast spatial resolution in Eclipse workstation. The CBCT‐QA was also analyzed by OBI‐workstation and a commercial software. Comparison was made to evaluation feasibility in a TPS environment.Results:The analysis of IQ was conducted in Eclipse v10.0 TPS. In‐slice geometric resolution was measured between 2‐rods in section CTP404 and repeated for all 4 rods with the difference between expected and measured values less than +/−0.1 cm. For HU, the difference between expected and measured values in HU was found much less than +/−40. Mean slice thickness measured by a distance on the wire proportional to scanner increment multiplying by a factor of 0.42. After repeating measurements to 4 wires, the average difference between expected and measured values was less +/−0.124 mm in slice thickness. HU uniformity was measured in section CTP486 with the tolerance less than +/−40 HU. Low contrast resolution in section CTP515 and high contrast resolution in section CTP528 were found to be 7 disks in diameter of 4 mm and 6 lp/cm, respectively. Eclipse TPS results indicated a good agreement to those obtained in OBI workstation and ImagePro software for major parameters.Conclusion:An analysis of IQ was proposed as an alternative CBCT QA processing. Based upon measured data assessment, proposed method was accurate and consistent to IQ evaluation and TG142 guideline. The approach was to utilize TPS resource, which can be valuable to re‐planning, verification, and delivery in adaptive therapy.
SU‐E‐J‐28: Assessment of Rotational Misalignment in Cervical Spine Treatments and Potential for 6DOF Couch Corrections
Authors: Williams B , Gladstone D 
Published: July 2014

Purpose:To quantify the magnitude of angular misalignments that may arise during spinal radiosurgery for metastases to cervical vertebrae and assess the ability of six‐degree of freedom (6DOF) alignment systems to apply appropriate corrections.Methods:A retrospective analysis of the distributions of rotational misalignments of cervical vertebrae based on planning CT and CBCT acquired for verification of patient positioning was performed. Fifteen patients being treated for cancers of the head and neck were immobilized using Type‐S head‐only thermoplastic masks mounted to an overlay board. Rigid registration was performed using commercially available software for individual vertebrae of each patient. Distributions of rotations were tabulated across all patients and vertebrae, modeled with a normal distribution, and 95% confidence intervals were estimated. Dosimetric consequences of maximal and 6DOF correctable misalignments are simulated.Results:Across all patients and vertebrae, 2/105 pitch rotations were >3° (1.9%), including 2/15 (13%) patients. Upper and lower 95% confidence intervals for pitch, yaw, and roll misalignments were [−2.3°, 3.3°], [−1.8°, 1.4°], and [−2.6°, 2.2°], respectively. Rotations for each vertebra were also considered. The greatest need for rotation appears to be for pitch correction of vertebra C4, with misalignment of 0.2° ± 1.9° observed, which predicts that a rotation >3° would be necessary 11.5% of the time that this vertebra is of interest.Conclusion:Empirical and model data presented here suggest that approximately 2–4% of vertebrae would require a rotation >3° in the sagittal plane, with some vertebrae more prone to rotational misalignments than others. Uncorrected rotational misalignment has the potential to alter dose distributions with respect to both treatment volumes and organs at risk and rotations >3° may require physical repositioning of the patient. Implementation of six‐degree of freedom couch systems may facilitate clinical flow after rotational misalignment is detected, and allow expeditious, automated setup corrections.Varian and Dartmouth‐Hitchcock Medical Center are parties to a customer acceptance evaluation agreement regarding the Varian 6 degree of freedom couch.
SU‐E‐J‐29: Audiovisual Biofeedback Improves Tumor Motion Consistency for Lung Cancer Patients
Authors: Lee D , Greer P , Arm J , Hunter P , Pollock S , Makhija K , Kim T , Keall P 
Published: July 2014

Purpose:To investigate whether the breathing‐guidance system: audiovisual (AV) biofeedback improves tumor motion consistency for lung cancer patients. This will minimize respiratory‐induced tumor motion variations across cancer imaging and radiotherapy procedues. This is the first study to investigate the impact of respiratory guidance on tumor motion.Methods:Tumor motion consistency was investigated with five lung cancer patients (age: 55 to 64), who underwent a training session to get familiarized with AV biofeedback, followed by two MRI sessions across different dates (pre and mid treatment). During the training session in a CT room, two patient specific breathing patterns were obtained before (Breathing‐Pattern‐1) and after (Breathing‐Pattern‐2) training with AV biofeedback. In each MRI session, four MRI scans were performed to obtain 2D coronal and sagittal image datasets in free breathing (FB), and with AV biofeedback utilizing Breathing‐Pattern‐2. Image pixel values of 2D images after the normalization of 2D images per dataset and Gaussian filter per image were used to extract tumor motion using image pixel values. The tumor motion consistency of the superior‐inferior (SI) direction was evaluated in terms of an average tumor motion range and period.Results:Audiovisual biofeedback improved tumor motion consistency by 60% (p value = 0.019) from 1.0±0.6 mm (FB) to 0.4±0.4 mm (AV) in SI motion range, and by 86% (p value < 0.001) from 0.7±0.6 s (FB) to 0.1±0.2 s (AV) in period.Conclusion:This study demonstrated that audiovisual biofeedback improves both breathing pattern and tumor motion consistency for lung cancer patients. These results suggest that AV biofeedback has the potential for facilitating reproducible tumor motion towards achieving more accurate medical imaging and radiation therapy procedures.