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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,315 records · Page 73
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

SU-C-BRC-04: Efficient Dose Calculation Algorithm for FFF IMRT with a Simplified Bivariate Gaussian Source Model

Purpose: To develop an efficient and accurate independent dose calculation algorithm with a simplified analytical source model for the quality assurance and safe delivery of Flattening Filter Free (FFF)-IMRT on an Elekta Versa HD. Methods: The source model consisted of a point source and a 2D bivariate Gaussian source, respectively modeling the primary photons and the combined effect of head scatter, monitor chamber backscatter and collimator exchange effect. The in-air fluence was firstly calculated by back-projecting the edges of beam defining devices onto the source plane and integrating the visible source distribution. The effect of the rounded MLC leaf end, tongue-and-groove and interleaf transmission was taken into account in the back-projection. The in-air fluence was then modified with a fourth degree polynomial modeling the cone-shaped dose distribution of FFF beams. Planar dose distribution was obtained by convolving the in-air fluence with a dose deposition kernel (DDK) consisting of the sum of three 2D Gaussian functions. The parameters of the source model and the DDK were commissioned using measured in-air output factors (Sc) and cross beam profiles, respectively. A novel method was used to eliminate the volume averaging effect of ion chambers in determining the DDK. Planar dose distributions of five head-and-neck FFF-IMRT plans were calculated and compared against measurements performed with a 2D diode array (MapCHECK™) to validate the accuracy of the algorithm. Results: The proposed source model predicted Sc for both 6MV and 10MV with an accuracy better than 0.1%. With a stringent gamma criterion (2%/2mm/local difference), the passing rate of the FFF-IMRT dose calculation was 97.2±2.6%. Conclusion: The removal of the flattening filter represents a simplification of the head structure which allows the use of a simpler source model for very accurate dose calculation. The proposed algorithm offers an effective way to ensure the safe delivery of FFF-IMRT.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

SU-F-I-15: Evaluation of a New MR-Compatible Respiratory Motion Device at 3T

Purpose: Recent advances in MRI-guided radiotherapy has inspired the development of MRI-compatible motion devices that simulate patient periodic motion in the scanner, particularly respiratory motion. Most commercial devices rely on non MR-safe ferromagnetic stepper motors which are not practical for regular QA testing. This work evaluates the motion performance of a new fully MRI compatible respiratory motion device at 3T. Methods: The QUASAR™ MRI-compatible respiratory motion phantom has been recently developed by Modus QA Inc., London, ON, Canada. The prototype is constructed from diamagnetic materials with linear motion generated using MRI-compatible piezoelectric motors that can be safely inserted in the scanner bore. The tumor was represented by a fillable sphere and is attached to the linear motion generator. The spherical tumor-representative and its surroundings were filled with different concentrations of MnCl2 to produce realistic relaxation times. The motion was generated along the longitudinal (H/F) axis of the bore using sinusoidal reference waveform (amplitude = 15 mm, frequency 0.25 Hz). Imaging was then performed on 3T Philips Achieva using a 32-channel cardiac coil. Fast 2D spoiled gradient-echo was used with a spatial resolution of 1.8 × 1.8 mm{sup 2} and slice thickness of 4 mm. The motion waveform was then measured on the resultant image series by tracking the centroid of the sphere through the time series. This image-derived measured motion was compared to the software-generated reference waveform. Results: No visible distortions from the device were observed on the images. Excellent agreement between the measured and the reference waveforms were obtained. Negligible motion was observed in the lateral (R/L) direction. Conclusion: Our investigation demonstrates that this piezo-electric motor design is effective at simulating periodic motion and is a potential candidate for MRI-radiotherapy respiratory motion simulation. Future work should focus on evaluating non-sinusoidal waveforms, fast 3D pulse sequences, and perform dosimetric QA.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

SU-F-J-197: A Novel Intra-Beam Range Detection and Adaptation Strategy for Particle Therapy

Purpose: In-vivo range detection/verification is crucial in particle therapy for effective and safe delivery. The state-of-art techniques are not sufficient for in-vivo on-line range verification due to conflicts among patient dose, signal statistics and imaging time. We propose a novel intra-beam range detection and adaptation strategy for particle therapy. Methods: This strategy uses the planned mid-range spots as probing beams without adding extra radiation to patients. Such choice of probing beams ensures the Bragg peaks to remain inside the tumor even with significant range variation from the plan. It offers sufficient signal statistics for in-beam positron emission tomography (PET) due to high positron activity of therapeutic dose. The probing beam signal can be acquired and reconstructed using in-beam PET that allows for delineation of the Bragg peaks and detection of range shift with ease of detection enabled by single-layered spots. If the detected range shift is within a pre-defined tolerance, the remaining spots will be delivered as the original plan. Otherwise, a fast re-optimization using range-shifted beamlets and accounting for the probing beam dose is applied to consider the tradeoffs posed by the online anatomy. Simulated planning and delivery studies were used to demonstrate the effectiveness of the proposed techniques. Results: Simulations with online range variations due to shifts of various foreign objects into the beam path showed successful delineation of the Bragg peaks as a result of delivering probing beams. Without on-line delivery adaptation, dose distribution was significantly distorted. In contrast, delivery adaptation incorporating detected range shift recovered well the planned dose. Conclusion: The proposed intra-beam range detection and adaptation utilizing the planned mid-range spots as probing beams, which illuminate the beam range with strong and accurate PET signals, is a safe, practical, yet effective approach to address range uncertainty issues in particle therapy.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

SU-F-T-134: Can We Use the Same Dose Constrains Learnt From Photon World to Plan Proton for Lung Cancer?

Purpose: To evaluate if the same DVH constrains used in photon plans can be safely used to plan proton therapy for lung cancer. Since protons and photons have different dose deposition patterns, the hypothesis is following DVH constrains derived from photon world is not safe for proton. Methods: We retrospectively evaluated plans for 11 lung cancer patients. Each patient was planned with photon and proton following the same dose constrains. Dose statistics on PTV, normal lung, heart and esophagus were extracted for comparison. gEUD for normal lung was calculated and compared between proton and photon plans. We calculated series of gEUDs for each plan by varying the parameter “a” in gEUD formula from 0.1 to 3, covering the whole confidence interval. Results: For all patients, proton plans yield similar PTV coverage and lower dose to heart and esophagus than photon plans. Normal lung V5 was 32.3 % on average in proton plans than 55.4 % in photon. Normal lung gEUD monotonically increased with increasing “a” for all proton and photon plans. For a given patient, the gEUD-proton(a) had a steeper slope than gEUD-photon(a). The two curves crossed for 8 out of 11 patients when “a” = [0.1, 3]. a-crossing ranged from 0.8 to 2.44 with an average of 1.15. For a<a-crossing, gEUD-proton was less than gEUD-photon and vice versa. Conclusion: The current clinical guideline is the lower normal lung V5 would associated with less complications. However, proton plans with a lower normal lung V5 could yield a higher gEUD than photon if the real “a” is larger than a-crossing. Since a-crossing was within the possible range of real “a”, simply following the normal lung V5 guideline for proton plan would not be a good practice. More comprehensive methods should be developed to evaluate the proton plan.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

SU-F-T-574: MLC Based SRS Beam Commissioning - Minimum Target Size Investigation

Purpose: To implement a MLC accelerator based SRS program using small fields down to 1 cm × 1 cm and to determine the smallest target size safe for clinical treatment. Methods: Computerized beam scanning was performed in water using a diode detector and a linac-head attached transmission ion chamber to characterize the small field dosimetric aspects of a 6 MV photon beam (Trilogy-Varian Medical Systems, Inc.). The output factors, PDD and profiles of field sizes 1, 2, 3, 4, and 10 cm{sup 2} were measured and utilized to create a new treatment planning system (TPS) model (AAA ver 11021). Static MLC SRS treatment plans were created and delivered to a homogeneous phantom (Cube 20, CIRS, Inc.) for a 1.0 cm and 1.5 cm “PTV” target. A 12 field DMLC plan was created for a 2.1 cm target. Radiochromic film (EBT3, Ashland Inc.) was used to measure the planar dose in the axial, coronal and sagittal planes. A micro ion chamber (0.007 cc) was used to measure the dose at isocenter for each treatment delivery. Results: The new TPS model was validated by using a tolerance criteria of 2% dose and 2 mm distance to agreement. For fields ≤ 3 cm{sup 2}, the max PDD, Profile and OF difference was 0.9%, 2%/2mm and 1.4% respectively. The measured radiochromic film planar dose distributions had gamma scores of 95.3% or higher using a 3%/2mm criteria. Ion chamber measurements for all 3 test plans effectively met our goal of delivering the dose accurately to within 5% when compared to the expected dose reported by the TPS (1 cm plan Δ= −5.2%, 1.5 cm plan Δ= −2.0%, 2 cm plan Δ= 1.5%). Conclusion: End to end testing confirmed that MLC defined SRS for target sizes ≥ 1.0 cm can be safely planned and delivered.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2016

MO-D-BRB-00: SBRT Workflow Overview

Increased use of SBRT and hypofractionation in radiation oncology practice has posted a number of challenges to medical physicist, ranging from planning, image-guided patient setup and on-treatment monitoring, to quality assurance (QA) and dose delivery. This symposium is designed to provide current knowledge necessary for the safe and efficient implementation of SBRT in various linac platforms, including the emerging digital linacs equipped with high dose rate FFF beams. Issues related to 4D CT, PET and MRI simulations, 3D/4D CBCT guided patient setup, real-time image guidance during SBRT dose delivery using gated/un-gated VMAT/IMRT, and technical advancements in QA of SBRT (in particular, strategies dealing with high dose rate FFF beams) will be addressed. The symposium will help the attendees to gain a comprehensive understanding of the SBRT workflow and facilitate their clinical implementation of the state-of-art imaging and planning techniques. Learning Objectives: Present background knowledge of SBRT, describe essential requirements for safe implementation of SBRT, and discuss issues specific to SBRT treatment planning and QA. Update on the use of multi-dimensional and multi-modality imaging for reliable guidance of SBRT. Discuss treatment planning and QA issues specific to SBRT. Provide a comprehensive overview of emerging digital linacs and summarize the key geometric and dosimetric features of the new generation of linacs for substantially improved SBRT. NIH/NCI; Varian Medical Systems; F. Yin, Duke University has a research agreement with Varian Medical Systems. In addition to research grant, I had a technology license agreement with Varian Medical Systems.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

MO-D-BRB-01: Fundamental Aspects of SBRT

Increased use of SBRT and hypofractionation in radiation oncology practice has posted a number of challenges to medical physicist, ranging from planning, image-guided patient setup and on-treatment monitoring, to quality assurance (QA) and dose delivery. This symposium is designed to provide current knowledge necessary for the safe and efficient implementation of SBRT in various linac platforms, including the emerging digital linacs equipped with high dose rate FFF beams. Issues related to 4D CT, PET and MRI simulations, 3D/4D CBCT guided patient setup, real-time image guidance during SBRT dose delivery using gated/un-gated VMAT/IMRT, and technical advancements in QA of SBRT (in particular, strategies dealing with high dose rate FFF beams) will be addressed. The symposium will help the attendees to gain a comprehensive understanding of the SBRT workflow and facilitate their clinical implementation of the state-of-art imaging and planning techniques. Learning Objectives: Present background knowledge of SBRT, describe essential requirements for safe implementation of SBRT, and discuss issues specific to SBRT treatment planning and QA. Update on the use of multi-dimensional and multi-modality imaging for reliable guidance of SBRT. Discuss treatment planning and QA issues specific to SBRT. Provide a comprehensive overview of emerging digital linacs and summarize the key geometric and dosimetric features of the new generation of linacs for substantially improved SBRT. NIH/NCI; Varian Medical Systems; F. Yin, Duke University has a research agreement with Varian Medical Systems. In addition to research grant, I had a technology license agreement with Varian Medical Systems.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

MO-D-BRB-02: SBRT Treatment Planning and Delivery

Increased use of SBRT and hypofractionation in radiation oncology practice has posted a number of challenges to medical physicist, ranging from planning, image-guided patient setup and on-treatment monitoring, to quality assurance (QA) and dose delivery. This symposium is designed to provide current knowledge necessary for the safe and efficient implementation of SBRT in various linac platforms, including the emerging digital linacs equipped with high dose rate FFF beams. Issues related to 4D CT, PET and MRI simulations, 3D/4D CBCT guided patient setup, real-time image guidance during SBRT dose delivery using gated/un-gated VMAT/IMRT, and technical advancements in QA of SBRT (in particular, strategies dealing with high dose rate FFF beams) will be addressed. The symposium will help the attendees to gain a comprehensive understanding of the SBRT workflow and facilitate their clinical implementation of the state-of-art imaging and planning techniques. Learning Objectives: Present background knowledge of SBRT, describe essential requirements for safe implementation of SBRT, and discuss issues specific to SBRT treatment planning and QA. Update on the use of multi-dimensional and multi-modality imaging for reliable guidance of SBRT. Discuss treatment planning and QA issues specific to SBRT. Provide a comprehensive overview of emerging digital linacs and summarize the key geometric and dosimetric features of the new generation of linacs for substantially improved SBRT. NIH/NCI; Varian Medical Systems; F. Yin, Duke University has a research agreement with Varian Medical Systems. In addition to research grant, I had a technology license agreement with Varian Medical Systems.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

MO-D-BRB-03: Quality Assurance of SBRT

Increased use of SBRT and hypofractionation in radiation oncology practice has posted a number of challenges to medical physicist, ranging from planning, image-guided patient setup and on-treatment monitoring, to quality assurance (QA) and dose delivery. This symposium is designed to provide current knowledge necessary for the safe and efficient implementation of SBRT in various linac platforms, including the emerging digital linacs equipped with high dose rate FFF beams. Issues related to 4D CT, PET and MRI simulations, 3D/4D CBCT guided patient setup, real-time image guidance during SBRT dose delivery using gated/un-gated VMAT/IMRT, and technical advancements in QA of SBRT (in particular, strategies dealing with high dose rate FFF beams) will be addressed. The symposium will help the attendees to gain a comprehensive understanding of the SBRT workflow and facilitate their clinical implementation of the state-of-art imaging and planning techniques. Learning Objectives: Present background knowledge of SBRT, describe essential requirements for safe implementation of SBRT, and discuss issues specific to SBRT treatment planning and QA. Update on the use of multi-dimensional and multi-modality imaging for reliable guidance of SBRT. Discuss treatment planning and QA issues specific to SBRT. Provide a comprehensive overview of emerging digital linacs and summarize the key geometric and dosimetric features of the new generation of linacs for substantially improved SBRT. NIH/NCI; Varian Medical Systems; F. Yin, Duke University has a research agreement with Varian Medical Systems. In addition to research grant, I had a technology license agreement with Varian Medical Systems.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

Masitinib is a broad coronavirus 3CL inhibitor that blocks replication of SARS-CoV-2

Targeting the main protease of SARS-CoV-2 Inside host cells, the RNA genome of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is translated into two polyproteins that are cleaved to give the individual viral proteins. The main viral protease, known as Mpro or 3CLpro, plays a key role in these cleavages, making it an important drug target. Drayman et al . identified eight drugs that target 3CLpro from a library of 1900 clinically safe drugs. Because of the challenge of working with SARS-CoV-2, they started by screening for drugs that inhibit the replication of a human coronavirus that causes the common cold. They then evaluated the top hits for inhibiting SARS-CoV-2 replication and for inhibiting 3CLpro. Masitinib, a broad antiviral, inhibited the main proteases of coronaviruses and picornaviruses and was effective in reducing SARS-CoV-2 replication in mice.

Drayman, Nir↗
DOE OSTI2015

The United States Culture Collection Network (USCCN): Enhancing Microbial Genomics Research through Living Microbe Culture Collections

The mission of the United States Culture Collection Network (USCCN; http://usccn.org) is "to facilitate the safe and responsible utilization of microbial resources for research, education, industry, medicine, and agriculture for the betterment of human kind." Microbial culture collections are a key component of life science research, biotechnology, and emerging global biobased economies. Representatives and users of several microbial culture collections from the United States and Europe gathered at the University of California, Davis, to discuss how collections of microorganisms can better serve users and stakeholders and to showcase existing resources available in public culture collections.

Boundy-Mills, K.↗
DOE OSTI2022

Software defined grid energy storage

Today, consumer battery installations are isolated, physical devices. Virtual power plants (VPPs) allow consumer devices to aggregate for grid services, but they are are vertically integrated, vendor controlled systems (e.g., Tesla’s VPP). Consumer batteries are therefore unable to participate in energy markets or other grid services outside what their vendor provides. We describe a software system that provides software control of multiple, networked battery energy storage systems in the electric grid. The system introduces two new ideas that enable flexible and dependable management of energy storage. The first is a virtual battery, which can either partition a battery or aggregate multiple batteries. The second is a reservation-based API which allows asynchronous control of batteries to meet contractual guarantees in a safe and dependable manner. Virtual batteries and a reservation-based API address the unique challenges of achieving high and efficient utilization of energy storage systems, including heterogeneity of battery systems such as varying C-rates, participation in energy markets, utility bill management systems, community resource sharing, and reliability. Using a testbed comprised of sonnen Inc. storage units installed in several homes and a lab, we demonstrate that virtualized batteries can seamlessly replace physical batteries, flexibly manage energy storage resources, isolate multiple clients using a shared battery, and create new energy storage applications.

25 ENERGY STORAGE↗
DOE OSTI2017

Solidify, An LLVM pass to compile LLVM IR into Solidity

The software currently compiles LLVM IR into Solidity (Ethereum’s dominant programming language) using LLVM’s pass library. Specifically, his compiler allows us to convert an arbitrary DSL into Solidity. We focus specifically on converting Domain Specific Languages into Solidity due to their ease of use, and provable properties. By creating a toolchain to compile lightweight domain-specific languages into Ethereum's dominant language, Solidity, we allow non-specialists to effectively develop safe and useful smart contracts. For example lawyers from a certain firm can have a proprietary DSL that codifies basic laws safely converted to Solidity to be securely executed on the blockchain. In another example, a simple provenance tracking language can be compiled and securely executed on the blockchain.

Kothapalli, Abhiram↗
DOE OSTI2022

pnnl/ssass-e

SSASSE software is responsible for validating, and verifying innovative safe scanning methodologies, models, architectures, and prototypes to safely assess operational technology (OT) installed in critical energy infrastructure.

Niddodi, Shwetha↗
DOE OSTI2025

Dirty Word Scanner

SAND2025-09142O Dirty Word Scanner helps prevent the accidental inclusion of sensitive terms by scaning files in repositories to catch "dirty words" before they are committed. While there are existing solutions focused on passwords and API keys, this tool offers additional features tailored to specific security needs. It will function as a standalone tool, incorporating advanced capabilities from similar tools to provide a comprehensive solution. This tool can unpack HDF5 files and examine their contents. It can display image, audio, and visual files to the user and request a manual determination of whether they are safe. It can also detect arbitrary binary files and ask the user to verify that they're safe. The tool enables sophisticated whitelisting of strings and regular expressions for cases where a term is sensitive in certain contexts but not in others. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

Gates, Jason [Sandia National Lab. (SNL-CA), Liver↗
DOE OSTI2014

Circumstances and outcomes of falls among high risk community-dwelling older adults

For older adults, falls threaten their health, independence, and quality of life. Knowing the circumstances surrounding falls is essential for understanding how behavioral and environmental factors interact in fall events. It is also important for developing and implementing interventions that are effective and acceptable to older adults. This study investigated the circumstances and injury outcomes of falls among community-dwelling older adults at high risk for falls. In this secondary analysis, we examined the circumstances and outcomes of falls experienced by 328 participants in the Dane County (Wisconsin) Safety Assessment for Elders (SAFE) Research Study. SAFE was a randomized controlled trial of a community-based multifactorial falls intervention for older adults at high risk for falls, conducted from October 2002 to December 2007. Participants were community-dwelling adults aged ≥65 years who reported at least one fall during the year after study enrollment. Falls were collected prospectively using monthly calendars. Everyone who reported a fall was contacted by telephone to determine the circumstances surrounding the event. Injury outcomes were defined as none, mild (injury reported but no treatment sought), moderate (treatment for any injury except head injury or fracture), and severe (treatment for head injury or fracture). Data were available for 1,172 falls. A generalized linear mixed model analysis showed that being aged ≥85 (OR = 2.1, 95% confidence interval [CI] = 1.2–3.9), female (OR = 2.1, 95% CI = 1.3–3.4), falling backward and landing flat (OR = 5.6, 95% CI = 2.9–10.5), sideways (OR = 4.6, 95% CI = 2.6–8.0) and forward (OR = 3.3, 95% CI = 2.0–5.7) were significantly associated with the likelihood of injury. Of 783 falls inside the home, falls in the bathroom were more than twice as likely to result in an injury compared to falls in the living room (OR = 2.4, 95% CI = 1.2–4.9). Most falls among these high risk older adults occurred inside the home. The likelihood of injury in the bathroom supports the need for safety modifications such as grab bars, and may indicate a need for assistance with bathing. These findings will help clinicians tailor fall prevention for their patients and have practical implications for retirement and assisted living communities and community-based fall prevention programs.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Prebiotic properties of Bacillus coagulans MA-13: production of galactoside hydrolyzing enzymes and characterization of the transglycosylation properties of a GH42 β-galactosidase

The spore-forming lactic acid bacterium Bacillus coagulans MA-13 has been isolated from canned beans manufacturing and successfully employed for the sustainable production of lactic acid from lignocellulosic biomass. Among lactic acid bacteria, B. coagulans strains are generally recognized as safe (GRAS) for human consumption. Low-cost microbial production of industrially valuable products such as lactic acid and various enzymes devoted to the hydrolysis of oligosaccharides and lactose, is of great importance to the food industry. Specifically, α- and β-galactosidases are attractive for their ability to hydrolyze not-digestible galactosides present in the food matrix as well as in the human gastrointestinal tract. In this work we have explored the potential of B. coagulans MA-13 as a source of metabolites and enzymes to improve the digestibility and the nutritional value of food. A combination of mass spectrometry analysis with conventional biochemical approaches has been employed to unveil the intra- and extra- cellular glycosyl hydrolase (GH) repertoire of B. coagulans MA-13 under diverse growth conditions. The highest enzymatic activity was detected on β-1,4 and α-1,6-glycosidic linkages and the enzymes responsible for these activities were unambiguously identified as β-galactosidase (GH42) and α-galactosidase (GH36), respectively. Whilst the former has been found only in the cytosol, the latter is localized also extracellularly. The export of this enzyme may occur through a not yet identified secretion mechanism, since a typical signal peptide is missing in the α-galactosidase sequence. A full biochemical characterization of the recombinant β-galactosidase has been carried out and the ability of this enzyme to perform homo- and hetero-condensation reactions to produce galacto-oligosaccharides, has been demonstrated. Probiotics which are safe for human use and are capable of producing high levels of both α-galactosidase and β-galactosidase are of great importance to the food industry. In this work we have proven the ability of B. coagulans MA-13 to over-produce these two enzymes thus paving the way for its potential use in treatment of gastrointestinal diseases.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2019

Neoadjuvant Chemotherapy does not Increase Complications in Oncoplastic Breast-Conserving Surgery

Background: Oncoplastic breast-conserving surgery (OBCS) broadens the indications for breast conservation. Neoadjuvant systemic chemotherapy (NAC) is used increasingly in the treatment of patients with early-stage and locally advanced breast cancer. This study aimed to evaluate the outcomes for patients who received NAC followed by OBCS. Methods: A retrospective chart review was performed for all patients who underwent OBCS involving the mastopexy/breast-reduction technique, including synchronous mastopexy/breast reduction for symmetry, at the University of Texas MD Anderson Cancer Center between January 2010 and January 2016. Patients who had received NAC were compared with those who had undergone surgery first. Demographic, treatment, and outcomes data were collected. Results: The study included 429 patients, corresponding to 713 breasts. Of these patients, 122, corresponding to 199 breasts, received NAC. The patients who received NAC were younger (p < 0.001) and had a more advanced cancer stage (p < 0.001). The overall complication rate per patient was 25.9%, with major complications occurring in 9.1% of the patients. After adjustment for risk factors, NAC was not shown to be associated with an increased risk of complications or delayed adjuvant radiation therapy (p = 0.37), irrespective of the chemotherapy regimen used or whether the interval between NAC and surgery was 4 weeks or longer. Conclusions: In a high-volume center, OBCS can be performed safely for carefully selected patients after NAC without an increased risk of complications or delayed adjuvant radiation therapy. An interval of at least 4 weeks between completion of NAC and surgery can be regarded as safe irrespective of the chemotherapy regimen used.

62 RADIOLOGY AND NUCLEAR MEDICINE↗