bluuebunny/crossref_metadata_2025_split huggingface dataset:
TU‐H‐CAMPUS‐TeP2‐05: Selective Protection of Normal Tissue by Cerium Oxide Nanoparticles During Radiation Therapy
Authors: Ouyang Z , Yasmin‐Karim S , Strack G , Sajo E , Ngwa W 
Published: July 2016

Purpose:Cerium oxide nanoparticles (CONPs) have unique pH dependent properties such that they act as a radical modulator. These properties may be used in radiation therapy (RT) to protect normal tissue. This work investigates the selective radioprotection of CONPs in‐vitro and potential for in‐situ delivery of CONPs in prostate cancer RT.Methods:i) Normal human umbilical vein endothelial cells (HUVEC) and human prostate cancer cells (PC‐3) were treated with 0 or 2 ng/mL CONPs (NP size: 5 nm). 2 Gy of 100 kVp radiation was delivered to the cells 4 hours after the CONP treatment. Cell viability was checked 48 hours later using MTS assays. ii) A prostate tumor was modeled as a 2‐cm diameter sphere. CONPs were proposed to be loaded in a hollow radiotherapy fiducial marker. The concentration profile for the CONPs within the tumor was modeled with a previously validated diffusion equation employed in other studies for nanoparticles 10 nm or less.Results:i) Without radiation, cell viability was above 90% when treated with 2 ng/mL CONPs for both HUVEC and PC‐3. After irradiation, a slightly higher viability was observed in HUVEC with CONPs than the ones without CONPs, and this effect was not observed in PC‐3. ii) Based on the calculations, 2 ng/mL of CONPs could be delivered to normal cells by diffusion with a 1 µg/mL initial concentration within two weeks.Conclusion:We conclude that CONPs can provide selective radioprotection. The delivery of needed concentrations of CONPs is feasible via in‐situ release from radiotherapy biomaterials (e.g. fiducials) loaded with the CONPs.
TU‐H‐CAMPUS‐IeP3‐01: Simultaneous PET Restoration and PET/CT Co‐Segmentation Using a Variational Method
Authors: Li L , Lu W , Tan S 
Published: July 2016

Purpose:PET images are usually blurred due to the finite spatial resolution, while CT images suffer from low contrast. Segment a tumor from either a single PET or CT image is thus challenging. To make full use of the complementary information between PET and CT, we propose a novel variational method for simultaneous PET image restoration and PET/CT images co‐segmentation.Methods:The proposed model was constructed based on the Γ‐convergence approximation of Mumford‐Shah (MS) segmentation model for PET/CT co‐segmentation. Moreover, a PET de‐blur process was integrated into the MS model to improve the segmentation accuracy. An interaction edge constraint term over the two modalities were specially designed to share the complementary information. The energy functional was iteratively optimized using an alternate minimization (AM) algorithm. The performance of the proposed method was validated on ten lung cancer cases and five esophageal cancer cases. The ground truth were manually delineated by an experienced radiation oncologist using the complementary visual features of PET and CT. The segmentation accuracy was evaluated by Dice similarity index (DSI) and volume error (VE).Results:The proposed method achieved an expected restoration result for PET image and satisfactory segmentation results for both PET and CT images. For lung cancer dataset, the average DSI (0.72) increased by 0.17 and 0.40 than single PET and CT segmentation. For esophageal cancer dataset, the average DSI (0.85) increased by 0.07 and 0.43 than single PET and CT segmentation.Conclusion:The proposed method took full advantage of the complementary information from PET and CT images.This work was supported in part by the National Cancer Institute Grants R01CA172638. Shan Tan and Laquan Li were supported in part by the National Natural Science Foundation of China, under Grant Nos. 60971112 and 61375018.
TU‐H‐CAMPUS‐IeP3‐03: Validation of Image Registration Methods for Brain Magnetic Resonance Imaging
Authors: Lin J , Fuentes D , Chandler A , Hazle J , Schellingerhout D , MacLellan C 
Published: July 2016

Purpose:To assess the performance of both commercial and open‐source co‐registration solutions as applied to intra‐subject, multi‐sequence, magnetic resonance (MR) images of the brain.Methods:Twenty (20) patients were imaged on clinical 3.0T MR scanners to obtain T2‐weighted (T2W), fluid attenuation inversion recovery (FLAIR), susceptibility weighted angiography (SWAN), and T1 post‐contrast (T1C) image sequences. Fiducial landmark sites (n=15 per sequence, 4 sequences per patient, 1200 total planned for 4 sequences and 20 patients, 1175 total realized) were specified throughout these image volumes to define identical locations across sequences. Both commercial (General Electric [GE] VolumeViewer) and open‐source software (Advanced Normalization Tools [ANTs]) registration solutions were applied using the T2W sequence as the fixed reference. Landmark and image similarity (cross‐correlation [CC], mutual information [MI]) based registrations were performed for all image pairs. Rigid (6DOF) and affine (12DOF) transformations were considered. The Euclidean Target‐to‐Registration Error (TRE) was calculated at all landmarks of each image pair.Results:Prior to registration, TRE values for FLAIR, SWAN, and T1C were 2.07 ± 0.55 mm, 2.63 ± 0.62 mm and 3.65 ± 2.00 mm, respectively. Post‐registration, the best (smallest) average TRE values for FLAIR, SWAN, and T1C were 1.55 ± 0.46 mm (rigid MI), 1.34 ± 0.23 mm (affine MI) and 1.06 ± 0.16 mm (GE), respectively.Conclusion:This study presents a methodology to quantify the registration accuracy of commercial algorithms (whose figures of merit are often not publically available, despite clinical use), and compares that accuracy to open‐source alternatives. All sequences, on average, were improved by spatial registrations that corrected for patient motion, and such motion itself was found to increase with time spent in the MR scanner. The neuroanatomical information encoded in these landmarks, as placed on images with different contrast mechanisms, collectively represents a comprehensive dataset for quantitative evaluation of clinically‐used registration software.A.C. is an employee of GE Healthcare. This research was supported in part by the National Cancer Institute (Cancer Center Support Grant CA016672 and Training Grant 5T32CA119930). J.S.L. acknowledges support from the Baylor College of Medicine Medical Scientist Training Program and the Cullen Trust for Higher Education Physician/Scientist Fellowship Program.
TU‐H‐CAMPUS‐JeP3‐03: Clinical Implementation of An Online Replanning Process
Authors: Ates O , Ahunbay E , Chen G , Lawton C , Li X 
Published: July 2016

Purpose:The purpose of this study is to report the clinical implementation of an online replanning process with CT‐on‐Rails to address daily interfractional variations.Methods:A treatment planning package (MONACO/ADMIRE/MOSAIQ, Elekta) is used to perform online adaptive replanning, using segment aperture morphing (SAM) algorithm implemented in MONACO, based on daily CTs acquired from a CT‐on‐Rails (ARTISTE, Siemens). The online replanning is implemented in prostate RT in the following workflow:(1) Generating a target contour based on the image of the day, using ADMIRE deformable image registration software with manual editing if necessary; (2) Automatically modifying segment apertures from the original plan using the SAM algorithm to account for the changes in the target from planning to daily CTs including deformation; (3) Calculating the dose distribution for the new apertures with the same MUs as in the original plan;(4) Transferring the new plan into MOSAIQ Record & Verify system;(5) Performing a pre‐delivery QA using both our home‐grown and RADCALC software (LifeLine);(6) Delivering the adaptive plan for the fraction.The entire workflow takes <10 min. using a 16‐CPU hardware.Results:The online adaptive replanning process was successfully applied during RT for prostate cancers. The adaptive plan significantly improved the plan quality in both target coverage and organs‐at‐risk (OAR) sparing when compared to the current standard of practice; IGRT repositioning plan. For the average of 10 prostate cases, PTV‐V100, Rectum‐V70, and Bladder‐V45 (%) coverages were (92.84 ± 1.61/97.61 ± 1.45/98.85 ± 1.13), (6.76 ± 2.37/5.40 ± 2.61/3.52 ± 0.94) and (8.20 ± 3.55/5.72 ± 2.61/6.68 ± 3.21) for the IGRT, online SAM, and reoptimization plans, respectively.Conclusion:The online adaptive replanning workflow is clinically practical for prostate RT and can quickly generate adaptive plans with superior plan qualities when compared to the repositioning plans, improving the management of interfractional variations.This study was partially supported by Elekta Inc.
TU‐H‐CAMPUS‐TeP3‐04: Probing the Dose Enhancement Due to a Clinically‐Relevant Concentration of Gold Nanoparticles and Yb‐169 Gamma Rays Using PRESAGE Dosimeters
Authors: Cho J , Alqathami M , Reynoso F , Cho S 
Published: July 2016

Purpose:To probe physical evidences of the dose enhancement due to a low/clinically‐relevant concentration of gold nanoparticles (GNPs) and Yb‐169 gamma rays using PRESAGE dosimeters.Methods:A PRESAGE cuvette was placed at approximately 2 mm above the plane containing three novel Yb‐169 brachytherapy seeds (3.2, 3.2, and 5.3 mCi each). Two types of PRESAGE dosimeters were used – plain PRESAGEs (controls) and PRESAGEs loaded with 0.02 wt. % of GNPs (GNP‐PRESAGEs). Each PRESAGE dosimeter was irradiated with different time durations (0 to 24 hours) to deliver 0, 4, 8, 16 and 24 Gy of dose. For a reference/comparison, both types of PRESAGEs were also irradiated using 250 kVp x‐rays with/without Er‐filter to deliver 0, 3, 10, and 30 Gy of dose. Er‐filter was used to emulate Yb‐169 spectrum using 250 kVp x‐rays. The absorption spectra of PRESAGEs were measured using a UV spectrophotometer and used to determine the corresponding optical densities (ODs).Results:GNP‐PRESAGEs exposed to Yb‐169 sources showed ∼65% increase in ODs compared with controls. When exposed to Er‐filtered and unfiltered 250 kVp x‐rays, they produced smaller increases in ODs, ∼41% and ∼37%, respectively. There was a linear relationship between ODs and delivered doses with a goodness‐of‐fit (R2) greater than 0.99.Conclusion:A notable increase in the ODs (∼65%) was observed for GNP‐PRESAGEs irradiated by Yb‐169 gamma rays. Considering the observed OD increases, it was highly likely that Yb‐169 gamma rays were more effective than both Er‐filtered and unfiltered 250 kVp x‐rays, in terms of producing the dose enhancement. Due to several unknown factors (e.g., possible difference in the dose response of GNP‐PRESAGEs vs. PRESAGEs), however, a further investigations is necessary to establish the feasibility of quantifying the exact amount of macroscopic or microscopic/local GNP‐mediated dose enhancement using PRESAGE or similar volumetric dosimeters. Supported by DOD/PCRP grant W81XWH‐12‐1‐0198This investigation was supported by DOD/PCRP grant W81XWH‐12‐1‐0198.
WE‐AB‐204‐00: Diversity and Inclusion in Medical Physics
Authors: Avery Stephen 
Published: July 2016

Many efforts have been made to increase diversity in the science workforce. In order for us to be competitive in innovation and ingenuity we need to reach out to any source of intellectual talent. Having greater diversity can only increase the creativity in medical physics. In order for students to succeed academically they need role models and mentors with whom they can identify. Literature has shown that racial and ethnic diversity has both direct and indirect positive effects on the educational outcomes, career advancement and motivation of students. Diversity not only focuses on race, ethnicity and gender, but it can also include socioeconomic status, sexual orientation and more. Underrepresented populations have had low numbers over the years not only in medical physics but also in the sciences in general. With the rapidly changing face of our country we need to address how we attract and train the next generation of scientists to stay competitive. It is necessary to examine the role that diversity and inclusion play in the long term goals of institutions, workplaces and classrooms. To increase innovation we must engage people from all walks of life with different perspectives and life experiences to solve the problems that we will face. Diversity should be viewed as a strategy to achieve our goals instead of acts of good citizenship. Many of today's businesses and corporations have discovered that embracing diversity prepares future leaders in today's global market.This lecture will provide insight to how differences within our society can drive innovation. We will provide an overview of the role diversity and inclusion plays in the clinic, education and research to develop the future workforce in medical physics.

Learning Objectives:
Understanding the role diversity and inclusion plays in medical physics.
The importance of developing education and research strategies for a global workforce.
How to develop a roadmap to diversity excellence within AAPM.
WE‐AB‐204‐03: Increasing Access to Medical Physics Education and Research Excellence (AMPERE)
Authors: Ngwa W. 
Published: July 2016

Many efforts have been made to increase diversity in the science workforce. In order for us to be competitive in innovation and ingenuity we need to reach out to any source of intellectual talent. Having greater diversity can only increase the creativity in medical physics. In order for students to succeed academically they need role models and mentors with whom they can identify. Literature has shown that racial and ethnic diversity has both direct and indirect positive effects on the educational outcomes, career advancement and motivation of students. Diversity not only focuses on race, ethnicity and gender, but it can also include socioeconomic status, sexual orientation and more. Underrepresented populations have had low numbers over the years not only in medical physics but also in the sciences in general. With the rapidly changing face of our country we need to address how we attract and train the next generation of scientists to stay competitive. It is necessary to examine the role that diversity and inclusion play in the long term goals of institutions, workplaces and classrooms. To increase innovation we must engage people from all walks of life with different perspectives and life experiences to solve the problems that we will face. Diversity should be viewed as a strategy to achieve our goals instead of acts of good citizenship. Many of today's businesses and corporations have discovered that embracing diversity prepares future leaders in today's global market.This lecture will provide insight to how differences within our society can drive innovation. We will provide an overview of the role diversity and inclusion plays in the clinic, education and research to develop the future workforce in medical physics.

Learning Objectives:
Understanding the role diversity and inclusion plays in medical physics.
The importance of developing education and research strategies for a global workforce.
How to develop a roadmap to diversity excellence within AAPM.
WE‐A‐BRC‐02: Lessons Learned: Clinical Trials and Operations
Authors: Evans S. 
Published: July 2016

Quality and safety in healthcare are inextricably linked. There are compelling data that link poor quality radiation therapy to inferior patient survival. Radiation Oncology clinical trial protocol deviations often involve incorrect target volume delineation or dosing, akin to radiotherapy incidents which also often involve partial geometric miss or improper radiation dosing. When patients with radiation protocol variations are compared to those without significant protocol variations, clinical outcome is negatively impacted. Traditionally, quality assurance in radiation oncology has been driven largely by new technological advances, and safety improvement has been driven by reactive responses to past system failures and prescriptive mandates recommended by professional organizations and promulgated by regulators. Prescriptive approaches to quality and safety alone often do not address the huge variety of process and technique used in radiation oncology. Risk‐based assessments of radiotherapy processes provide a mechanism to enhance quality and safety, both for new and for established techniques. It is imperative that we explore such a paradigm shift at this time, when expectations from patients as well as providers are rising while available resources are falling. There is much we can learn from our past experiences to be applied towards the new risk‐based assessments.

Learning Objectives:
Understand the impact of clinical and technical quality on outcomes
Understand the importance of quality care in radiation oncology
Learn to assess the impact of quality on clinical outcomesD. Followill, NIH Grant CA180803
WE‐AB‐BRA‐01: Biodistribution of Paclitaxel‐Loaded Nanodroplets for Prostate Cancer Management Using Ultrasound‐Mediated Drug Delivery Under MRGuidance
Authors: Gupta R , Cvetkovic D , Wang B , Chen L , Ma C 
Published: July 2016

Purpose:To study the biodistribution of paclitaxel‐loaded nanodroplets in vivo in order to evaluate the efficacy of focused ultrasound (FUS)‐mediated drug delivery under MR‐guidance to prostate tumor.Methods:Poly {ethylene oxide}‐co‐poly {D, L‐lactide} (PDLA) nanodroplets loaded with fluorescently labeled‐paclitaxel (F‐PTX) were synthesized using solid dispersion technique. Human prostate cancer, LNCaP cells were implanted orthotopically in prostates of male nude mice. Tumor‐bearing mice (n=3) were injected with 0.1% F‐PTX, 2% PDLA nanodroplets using tail vein. At chosen time points (30min; 2h; 4h; 6h; 12h; 24h) animals were anesthetized, blood was collected by eye bleed, animals were sacrificed, tumor and vital organs (liver, spleen, lung and heart) were excised, cut and weighted. Then the organ was homogenized, incubated in lysis buffer and centrifuged. The lysates were read using fluorescence spectrophotometer (Excitation‐ 496nm, Emission– 524nm). Fluorescence readings were compared with values from the standard calibration curve. Tumor‐bearing mice (n=3) were also injected with 0.1% F‐PTX solution (fluorescent drug in free form).Results:Quantitative analysis showed 20% of the injected drug‐loaded nanodroplets in the tumor, 30 min after systemic injection; which increased to 30% after 2h; 35% after 4h; then decreased to 27% after 6h; 11% after 12h and 5% after 24h. When drug in free form was injected, drug accumulation in the tumor was 7% within 30mnt; 8% within 2h; 10% within 4h; 9% within 6h, 3% within 12h and 2% within 24h. Liver showed major drug accumulation for drug‐loaded nanodroplets while heart and lung showed less. For drug in free form, liver and spleen showed maximum drug concentrations while heart showed concentrations similar to that in tumor.Conclusion:Present work indicates that the optimum time for applying focused ultrasound is after 4h of systemically injecting drug‐loaded nanodroplets. This would increase treatment efficacy and provide preclinical data for FUS‐mediated drug delivery under MR‐guidance.
WE‐AB‐BRA‐08: Correction of Patient Motion in C‐Arm Cone‐Beam CT Using 3D‐2D Registration
Authors: Ouadah S , Jacobson M , Stayman JW , Ehtiati T , Siewerdsen JH 
Published: July 2016

Purpose:Intraoperative C‐arm cone‐beam CT (CBCT) is subject to artifacts arising from patient motion during the fairly long (∼5–20 s) scan times. We present a fiducial free method to mitigate motion artifacts using 3D‐2D image registration that simultaneously corrects residual errors in geometric calibration.Methods:A 3D‐2D registration process was used to register each projection to DRRs computed from the 3D image by maximizing gradient orientation (GO) using the CMA‐ES optimizer. The resulting rigid 6 DOF transforms were applied to the system projection matrices, and a 3D image was reconstructed via model‐based image reconstruction (MBIR, which accommodates the resulting noncircular orbit). Experiments were conducted using a Zeego robotic C‐arm (20 s, 200°, 496 projections) to image a head phantom undergoing various types of motion: 1) 5° lateral motion; 2) 15° lateral motion; and 3) 5° lateral motion with 10 mm periodic inferior‐superior motion. Images were reconstructed using a penalized likelihood (PL) objective function, and structural similarity (SSIM) was measured for axial slices of the reconstructed images. A motion‐free image was acquired using the same protocol for comparison.Results:There was significant improvement (p < 0.001) in the SSIM of the motion‐corrected (MC) images compared to uncorrected images. The SSIM in MC‐PL images was >0.99, indicating near identity to the motion‐free reference. The point spread function (PSF) measured from a wire in the phantom was restored to that of the reference in each case.Conclusion:The 3D‐2D registration method provides a robust framework for mitigation of motion artifacts and is expected to hold for applications in the head, pelvis, and extremities with reasonably constrained operative setup. Further improvement can be achieved by incorporating multiple rigid components and non‐rigid deformation within the framework. The method is highly parallelizable and could in principle be run with every acquisition.Research supported by National Institutes of Health Grant No. R01‐EB‐017226 and academic‐industry partnership with Siemens Healthcare (AX Division, Forcheim, Germany).
WE‐AB‐BRA‐09: Registration of Preoperative MRI to Intraoperative Radiographs for Automatic Vertebral Target Localization
Authors: De Silva T , Uneri A , Ketcha M , Reaungamornrat S , Goerres J , Vogt S , Kleinszig G , Wolinsky J , Siewerdsen JH 
Published: July 2016

Purpose:Accurate localization of target vertebrae is essential to safe, effective spine surgery, but wrong‐level surgery occurs with surprisingly high frequency. Recent research yielded the “LevelCheck” method for 3D‐2D registration of preoperative CT to intraoperative radiographs, providing decision support for level localization. We report a new method (MR‐LevelCheck) to perform 3D‐2D registration based on preoperative MRI, presenting a solution for the increasingly common scenario in which MRI (not CT) is used for preoperative planning.Methods:Direct extension of LevelCheck is confounded by large mismatch in image intensity between MRI and radiographs. The proposed method overcomes such challenges with a simple vertebrae segmentation. Using seed points at centroids, vertebrae are segmented using continuous max‐flow method and dilated by 1.8 mm to include surrounding cortical bone (inconspicuous in T2w‐MRI). MRI projections are computed (analogous to DRR) using segmentation and registered to intraoperative radiographs. The method was tested in a retrospective IRB‐approved study involving 11 patients undergoing cervical, thoracic, or lumbar spine surgery following preoperative MRI. Registration accuracy was evaluated in terms of projection‐distance‐error (PDE) between the true and estimated location of vertebrae in each radiograph.Results:The method successfully registered each preoperative MRI to intraoperative radiographs and maintained desirable properties of robustness against image content mismatch, and large capture range. Segmentation achieved Dice coefficient = 89.2 ± 2.3 and mean‐absolute‐distance (MAD) = 1.5 ± 0.3 mm. Registration demonstrated robust performance under realistic patient variations, with PDE = 4.0 ± 1.9 mm (median ± iqr) and converged with run‐time = 23.3 ± 1.7 s.Conclusion:The MR‐LevelCheck algorithm provides an important extension to a previously validated decision support tool in spine surgery by extending its utility to preoperative MRI. With initial studies demonstrating PDE <5 mm and 0% failure rate, the method is now in translation to larger scale prospective clinical studies.S. Vogt and G. Kleinszig are employees of Siemens Healthcare