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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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26 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Patient performance–based plan parameter optimization for prostate cancer in tomotherapy

The purpose of this study is to evaluate the influence of treatment-planning parameters on the quality of treatment plans in tomotherapy and to find the optimized planning parameter combinations when treating patients with prostate cancer under different performances. A total of 3 patients with prostate cancer with Eastern Cooperative Oncology Group (ECOG) performance status of 2 or 3 were included in this study. For each patient, 27 treatment plans were created using a combination of planning parameters (field width of 1, 2.5, and 5 cm; pitch of 0.172, 0.287, and 0.43; and modulation factor of 1.8, 3, and 3.5). Then, plans were analyzed using several dosimetrical indices: the prescription isodose to target volume (PITV) ratio, homogeneity index (HI), conformity index (CI), target coverage index (TCI), modified dose HI (MHI), conformity number (CN), and quality factor (QF). Furthermore, dose-volume histogram of critical structures and critical organ scoring index (COSI) were used to analyze organs at risk (OAR) sparing. Interestingly, treatment plans with a field width of 1 cm showed more favorable results than others in the planning target volume (PTV) and OAR indices. However, the treatment time of the 1-cm field width was 3 times longer than that of plans with a field width of 5 cm. There was no substantial decrease in treatment time when the pitch was increased from 0.172 to 0.43, but the PTV indices were slightly compromised. As expected, field width had the most significant influence on all of the indices including PTV, OAR, and treatment time. For the patients with good performance who can tolerate a longer treatment time, we suggest a field width of 1 cm, pitch of 0.172, and modulation factor of 1.8; for the patients with poor performance status, field width of 5 cm, pitch of 0.287, and a modulation factor of 3.5 should be considered.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2015

SU-E-T-119: Analysis the Efficacy of Different Radiotherapy Methods and Failure Mode in No-Metastasis Esophageal Squamous Cell Carcinoma

Purpose: To evaluate the curative effect of radio (chemo) therapy and mode of treatment failure in no-metastasis and lesion length ≤ 5.0cm esophageal squamous cell carcinoma (ESCC). Methods: There were 158 eligible patients were retrospectively analyzed, to analysis the curative effect of radio (chemo) therapy, prognosis factors, toxicity and prognostic index model. Results: To all patients the 1, 3, 5 overall survival rate were 83.54%, 52.53%, 32.58%, the local recurrence rate were 15.08%, 33.60% and 38.14%; distant metastasis rate were 10.64%, 25.21% and 36.06%; tumor specific survival rate were 76.64%, 54.07% and 44.51%. Multivariate analysis showed that patients with ECOG grade (χ2=13.945, P=0.000), short-term effect (χ2=19.360, P=0.000) and different radiotherapy methods (χ2=9.866, P=0.002) as the independent prognostic factors. Prognostic index model showed that the survival rate was significantly higher in the lower value of PI group than in the larger value of PI group (χ2=49.19, P=0.0000). In our whole group, there were simple locoregional recurrence (LR) 40 cases (25.3%), simple Distant metastasis (DM) 31 cases (19.6%), LR and DM in 14 cases (8.9%) after treatment. The chi-square test showed that there were no significant difference in the incidence of Elective Nodal Irradiation (ENI )and Involved Field Irradiation (IFI) patients with LR and DM ( χ2=2.363, 2.950, P=0.124, 0.085). Conclusion: Radio (chemo) therapy has a good curative effect in no-metastasis and lesion length ≤ 5.0cm ESCC patients.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2019

First-Line Gemcitabine and Nab-Paclitaxel Chemotherapy for Localized Pancreatic Ductal Adenocarcinoma

Background: Preoperative chemotherapy provides early treatment of micro-metastases and guaranteed delivery of all components of multimodality therapy for localized pancreatic ductal adenocarcinoma (PDAC). For locally advanced (LA) PDAC, induction chemotherapy is the standard of care. This study evaluated the use of gemcitabine and nab-paclitaxel (Gem/nab-P) as first-line therapy for localized PDAC. Methods: Clinicopathologic features, treatment, and outcomes were evaluated for 99 patients with localized PDAC. The patients were staged using previously published criteria as follows: potentially resectable (PR), borderline type A (BR-A) (anatomy amenable to vascular resection), BR-B (biology suspicious for metastatic disease including high CA19-9), BR–C (comorbidities requiring medical optimization), and LA. Results: The 99 patients (PR/BR/LA: 45/14/40) were treated with Gem/nab-P. Clinical staging showed that 20 patients had PR or BR-A disease, whereas 39 patients had BR-B or BR-C disease. The BR-B+C cases included one or more of the following: age of 80 years or older (13%), Eastern Cooperative Oncology Group performance status (ECOG PS) of 2 or more (13%), moderate to severe comorbidities (55%), CA19-9 of 1000 or higher (28%), and suspicion for metastases (21%). The majority of the patients received biweekly Gem/nab-P dosing, which was well tolerated. Pancreatectomy was performed for 12 (60%) of 20 patients with PR+BR-A, 2 (5%) of 39 patients with BR-B+C, and 1 (3%) of 40 patients with LA disease. During a median follow-up period of 26 months, the median overall survival (OS) period was 18 months (95% confidence interval [CI], 15.6–20.5 months) for all the patients, 17 months (95% CI, 14.6–19.5 months) for the unresected patients, and not reached for the resected patients (p = 0.028 for resected vs unresected patients). Conclusions: A significant number of patients with radiographically resectable PDAC albeit aggressive biology (BR-B), medically inoperable conditions (BR-C), or both received biweekly first-line Gem/nab-P. The resection rates were lower for the BR-B/BR-C patients than for the PR/BR-A patients (hazard ratio [HR], 0.43; 95% CI, 0.19–1.00; p = 0.05).

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Is Robotic-Assisted Surgery Safe in the Elderly Population? An Analysis of Gynecologic Procedures in Patients ≥ 65 Years Old

Background: The elderly population is expanding worldwide but is underrepresented in clinical trials. We sought to assess the safety of robotic gynecologic surgery in an elderly cohort and to identify factors associated with unfavorable outcomes. Methods: All patients ≥ 65 years who underwent a robotically assisted procedure at a single institution between May 2007 to December 2016 were divided into three age groups: 65–74 (Group 1); 75–84 (Group 2); ≥ 85 (Group 3). Perioperative outcomes were recorded in patients who did not require conversion to laparotomy. We compared clinical variables among groups and performed multivariate logistic regression to detect variables associated with major complications (≥ Grade 3) or 90-day mortality. Results: We retrospectively identified 982 cases: 685 in Group 1; 249 in Group 2; 48 in Group 3. Median age = 71 years. Median BMI = 28.9. Malignancy was documented in 72.8% of cases; the majority were endometrial cancer (61.8%). Thirty-four patients (3.5%) were readmitted within 30 days. Seventy-seven (7.8%) had a postoperative complication, and 23 (2.3%) had a major complication. Ninety-day mortality was 0.5%. There was significant difference between groups with respect to body mass index (P = 0.026), ECOG PS (P ≤ 0.001), > 5 comorbidities (P = 0.005), hospital stay (P < 0.001), major complications (P = 0.001), and 90-day mortality (P < 0.001). On multivariable logistic regression, age ≥ 85 years was associated with major complications. Body mass index, age ≥ 85 years, and major complications were significantly associated with 90-day mortality. Conclusions: Robotic-assisted surgery appears to be safe in an elderly cohort. The incidence of overall and major complications is consistent with those reported in the literature. Patients ≥ 85 years old appear to be at higher risk of unfavorable outcomes.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2024

Bayesian inference of structured latent spaces from neural population activity with the orthogonal stochastic linear mixing model

The brain produces diverse functions, from perceiving sounds to producing arm reaches, through the collective activity of populations of many neurons. Determining if and how the features of these exogenous variables (e.g., sound frequency, reach angle) are reflected in population neural activity is important for understanding how the brain operates. Often, high-dimensional neural population activity is confined to low-dimensional latent spaces. However, many current methods fail to extract latent spaces that are clearly structured by exogenous variables. This has contributed to a debate about whether or not brains should be thought of as dynamical systems or representational systems. Here, we developed a new latent process Bayesian regression framework, the orthogonal stochastic linear mixing model (OSLMM) which introduces an orthogonality constraint amongst time-varying mixture coefficients, and provide Markov chain Monte Carlo inference procedures. We demonstrate superior performance of OSLMM on latent trajectory recovery in synthetic experiments and show superior computational efficiency and prediction performance on several real-world benchmark data sets. We primarily focus on demonstrating the utility of OSLMM in two neural data sets: μ ECoG recordings from rat auditory cortex during presentation of pure tones and multi-single unit recordings form monkey motor cortex during complex arm reaching. We show that OSLMM achieves superior or comparable predictive accuracy of neural data and decoding of external variables (e.g., reach velocity). Most importantly, in both experimental contexts, we demonstrate that OSLMM latent trajectories directly reflect features of the sounds and reaches, demonstrating that neural dynamics are structured by neural representations. Together, these results demonstrate that OSLMM will be useful for the analysis of diverse, large-scale biological time-series datasets.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

Sex Differences in Odds of Brain Metastasis and Outcomes by Brain Metastasis Status after Advanced Melanoma Diagnosis

Sex differences in cancer are well-established. However, less is known about sex differences in diagnosis of brain metastasis and outcomes among patients with advanced melanoma. Using a United States nationwide electronic health record-derived de-identified database, we evaluated patients diagnosed with advanced melanoma from 1 January 2011–30 July 2022 who received an oncologist-defined rule-based first line of therapy (n = 7969, 33% female according to EHR, 35% w/documentation of brain metastases). The odds of documented brain metastasis diagnosis were calculated using multivariable logistic regression adjusted for age, practice type, diagnosis period (pre/post-2017), ECOG performance status, anatomic site of melanoma, group stage, documentation of non-brain metastases prior to first-line of treatment, and BRAF positive status. Real-world overall survival (rwOS) and progression-free survival (rwPFS) starting from first-line initiation were assessed by sex, accounting for brain metastasis diagnosis as a time-varying covariate using the Cox proportional hazards model, with the same adjustments as the logistic model, excluding group stage, while also adjusting for race, socioeconomic status, and insurance status. Adjusted analysis revealed males with advanced melanoma were 22% more likely to receive a brain metastasis diagnosis compared to females (adjusted odds ratio [aOR]: 1.22, 95% confidence interval [CI]: 1.09, 1.36). Males with brain metastases had worse rwOS (aHR: 1.15, 95% CI: 1.04, 1.28) but not worse rwPFS (adjusted hazard ratio [aHR]: 1.04, 95% CI: 0.95, 1.14) following first-line treatment initiation. Among patients with advanced melanoma who were not diagnosed with brain metastases, survival was not different by sex (rwOS aHR: 1.06 [95% CI: 0.97, 1.16], rwPFS aHR: 1.02 [95% CI: 0.94, 1.1]). This study showed that males had greater odds of brain metastasis and, among those with brain metastasis, poorer rwOS compared to females, while there were no sex differences in clinical outcomes for those with advanced melanoma without brain metastasis.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2023

Implantable neuromodulation system for closed-loop stimulation and recording simultaneously at multiple brain sets

The present disclosure relates to a modular system for deep brain stimulation (DBS) and electrocorticography (ECoG). The system may have an implantable neuromodulator for generating electrical stimulation signals adapted to be applied to a desired region of a brain via an attached electrode array. An aggregator module may be used for collecting and aggregating electrical signals and transmitting the electrical signals to the neuromodulator. A control module may be used which is in communication with the aggregator module for controlling generation of the electrical signals and transmitting the electrical signals to the aggregator.

Pannu, Satinderpall S.↗
DOE OSTI2011

Flexible, foldable, actively multiplexed, high-density electrode array for mapping brain activity in vivo

Arrays of electrodes for recording and stimulating the brain are used throughout clinical medicine and basic neuroscience research, yet are unable to sample large areas of the brain while maintaining high spatial resolution because of the need to individually wire each passive sensor at the electrode-tissue interface. To overcome this constraint, we developed new devices that integrate ultrathin and flexible silicon nanomembrane transistors into the electrode array, enabling new dense arrays of thousands of amplified and multiplexed sensors that are connected using fewer wires. We used this system to record spatial properties of cat brain activity in vivo, including sleep spindles, single-trial visual evoked responses and electrographic seizures. We found that seizures may manifest as recurrent spiral waves that propagate in the neocortex. As a result, the developments reported here herald a new generation of diagnostic and therapeutic brain-machine interface devices.

high spatial resolution↗