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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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All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

Ten-Year Outcomes: The Clinical Utility of Single Photon Emission Computed Tomography/Computed Tomography Capromab Pendetide (Prostascint) in a Cohort Diagnosed With Localized Prostate Cancer

Purpose: To evaluate the clinical utility of capromab pendetide imaging with single photon emission computed tomography coregistration with computed tomography (SPECT/CT) in primary prostate cancer (CaP) for pretreatment prognostic staging and localization of biologic target volumes (BTV) for individualized image-guided radiotherapy dose escalation (IGRT-DE). Methods and Materials: Patients consecutively presenting for primary radiotherapy (February 1997 to December 2002), having a clinical diagnosis of localized CaP, were evaluated for tumor stage using conventional staging and SPECT/CT (N = 239). Distant metastatic uptake (mets) were identified by SPECT/CT in 22 (9.2%). None of the suspected mets could be clinically confirmed. Thus, all subjects were followed without alteration in disease management. The SPECT/CT pelvic images defined BTV for IGRT-DE (+150% brachytherapy dose) without (n = 150) or with (n = 89) external radiation of 45 Gy. The National Comprehensive Cancer Network criteria defined risk groups (RG). The median survivor follow-up was 7 years. Biochemical disease-free survival (bDFS) was reported by clinical nadir +2 ng/mL (CN+2) criteria. Statistical analyses included Kaplan-Meier, multivariate analysis, and Concordance-index models. Results: At 10-year analyses, overall survival was 84.8% and bDFS was 84.6%. With stratification by RG, CN+2 bDFS was 93.5% for the low-RG (n = 116), 78.7% for the intermediate-RG (n = 94), and 68.8% for the high-RG (n = 29), p = 0.0002. With stratification by pretreatment SPECT/CT findings, bDFS was 65.5% in patients with suspected mets (n = 22) vs. 86.6% in patients with only localized uptake (n = 217), p = 0.0014. CaP disease-specific survival (DSS) was 97.7% for the cohort. With stratification by SPECT/CT findings, DSS was 86.4% (with suspected mets) vs. 99.0% (localized only), p = 0.0001. Using multivariate analysis, the DSS hazard ratio for SPECT/CT findings (mets vs. localized) was 3.58 (p = 0.0026). Concordance-index tests, based on all data, by CN+2 bDFS criteria were 0.710 for RG alone and 0.773 for SPECT/CT + RG. Conclusions: Through long-term outcomes we demonstrate statistically significant bDFS and DSS predictive value for pretreatment capromab pendetide SPECT/CT imaging in primary CaP. Dual clinical utility is demonstrated, using SPECT/CT to define BTV for individualized IGRT-DE.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2014

Comprehensive Craniospinal Radiation for Controlling Central Nervous System Leukemia

Purpose: To determine the benefit of radiation therapy (RT) in resolution of neurologic symptoms and deficits and whether the type of RT fields influences central nervous system (CNS) control in adults with CNS leukemia. Methods and Materials: A total of 163 adults from 1996 to 2012 were retrospectively analyzed. Potential associations between use of radiation and outcome were investigated by univariate and multivariate analysis. Results: The median survival time was 3.8 months after RT. Common presenting symptoms were headache in 79 patients (49%), cranial nerve VII deficit in 46 (28%), and cranial nerve II deficit in 44 (27%). RT was delivered to the base of skull in 48 patients (29%), to the whole brain (WB) in 67 (41%), and to the craniospinal axis (CS) in 48 (29%). Among 149 patients with a total of 233 deficits, resolution was observed in 34 deficits (15%), improvement in 126 deficits (54%), stability in 34 deficits (15%), and progression in 39 deficits (17%). The 12-month CNS progression-free survival was 77% among those receiving CS/WB and 51% among those receiving base of skull RT (P=.02). On multivariate analysis, patients who did not undergo stem cell transplantation after RT and base of skull RT were associated with worse CNS progression-free survival. Conclusions: Improvement or resolution of symptoms occurred in two thirds of deficits after RT. Comprehensive radiation to the WB or CS seems to offer a better outcome, especially in isolated CNS involvement.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

Impact of Consolidation Radiation Therapy in Stage III-IV Diffuse Large B-cell Lymphoma With Negative Post-Chemotherapy Radiologic Imaging

Purpose: While consolidation radiation therapy (i.e., RT administered after chemotherapy) is routine treatment for patients with early-stage diffuse large B-cell lymphoma (DLBCL), the role of consolidation RT in stage III-IV DLBCL is controversial. Methods and Materials: Cases of patients with stage III-IV DLBCL treated from 1991 to 2009 at Duke University, who achieved a complete response to chemotherapy were reviewed. Clinical outcomes were calculated using the Kaplan-Meier method and were compared between patients who did and did not receive RT, using the log-rank test. A multivariate analysis was performed using Cox proportional hazards model. Results: Seventy-nine patients were identified. Chemotherapy (median, 6 cycles) consisted of anti-CD20 antibody rituximab combined with cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP; 65%); cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP; 22%); or other (13%). Post-chemotherapy imaging consisted of positron emission tomography (PET)/computed tomography (CT) (73%); gallium with CT (14%); or CT only (13%). Consolidation RT (median, 25 Gy) was given to involved sites of disease in 38 (48%) patients. Receipt of consolidation RT was associated with improved in-field control (92% vs. 69%, respectively, p = 0.028) and event-free survival (85% vs. 65%, respectively, p = 0.014) but no difference in overall survival (85% vs. 78%, respectively, p = 0.15) when compared to patients who did not receive consolidation RT. On multivariate analysis, no RT was predictive of increased risk of in-field failure (hazard ratio [HR], 8.01, p = 0.014) and worse event-free survival (HR, 4.3, p = 0.014). Conclusions: Patients with stage III-IV DLBCL who achieve negative post-chemotherapy imaging have improved in-field control and event-free survival with low-dose consolidation RT.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Measurement of the t-Channel Single Top Quark Production Cross Section in pp Collisions at {radical}(s)=7 TeV

Electroweak production of the top quark is measured for the first time in pp collisions at {radical}(s)=7 TeV, using a data set collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 36 pb{sup -1}. With an event selection optimized for t-channel production, two complementary analyses are performed. The first one exploits the special angular properties of the signal, together with background estimates from the data. The second approach uses a multivariate analysis technique to probe the compatibility with signal topology expected from electroweak top-quark production. The combined measurement of the cross section is 83.6{+-}29.8(stat+syst){+-}3.3(lumi) pb, consistent with the standard model expectation.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Association of Locoregional Control With High Body Mass Index in Women Undergoing Breast Conservation Therapy for Early-Stage Breast Cancer

Purpose: Obesity, as measured by the body mass index (BMI), is a risk factor for distant recurrence and decreased survival in breast cancer. We sought to determine whether the BMI correlated with local recurrence and reduced survival in a cohort of predominantly obese women treated with breast conservation therapy. Methods and Materials: From 1998 to 2010, 154 women with early-stage invasive breast cancer and 39 patients with ductal carcinoma in situ underwent prone whole breast irradiation. Cox proportional hazards regression, Kaplan-Meier methods with the log-rank test, and multivariate analysis were used to explore the association of the outcomes with the BMI. Results: The median patient age was 60 years, and the median follow-up duration was 73 months. The median BMI was 33.2 kg/m{sup 2}; 91% of the patients were overweight (BMI ≥25 kg/m{sup 2}) and 69% of the patients were clinically obese (BMI ≥30 kg/m{sup 2}). The BMI was significantly associated with the locoregional recurrence-free interval for patients with invasive cancer and ductal carcinoma in situ (hazard ratio [HR], 1.09; P=.047). Also, a trend was seen for increased locoregional recurrence with a higher BMI (P=.09) for patients with invasive disease, which was significant when examining the outcomes with a BMI stratified by the median value of 33.2 kg/m{sup 2} (P=.008). A greater BMI was also significantly associated with decreased distant recurrence-free interval (HR, 1.09; P=.011) and overall survival (HR, 1.09; P=.004); this association remained on multivariate analysis (distant recurrence-free interval, P=.034; overall survival, P=.0007). Conclusions: These data suggest that the BMI might affect the rate of locoregional recurrence in breast cancer patients. A higher BMI predicted a worse distant recurrence-free interval and overall survival. The present investigation adds to the increasing evidence that BMI is an important prognostic factor in early-stage breast cancer treated with breast conservation therapy.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Dose-Response for Stereotactic Body Radiotherapy in Early-Stage Non-Small-Cell Lung Cancer

Purpose: To compare the efficacy of three lung stereotactic body radiotherapy (SBRT) regimens in a large institutional cohort. Methods: Between 2004 and 2009, 130 patients underwent definitive lung cancer SBRT to a single lesion at the Mallinckrodt Institute of Radiology. We delivered 18 Gy Multiplication-Sign 3 fractions for peripheral tumors (n = 111) and either 9 Gy Multiplication-Sign 5 fractions (n = 8) or 10 Gy Multiplication-Sign 5 fractions (n = 11) for tumors that were central or near critical structures. Univariate and multivariate analysis of prognostic factors was performed using the Cox proportional hazard model. Results: Median follow-up was 11, 16, and 13 months for the 9 Gy Multiplication-Sign 5, 10 Gy Multiplication-Sign 5, and 18 Gy Multiplication-Sign 3 groups, respectively. Local control statistics for Years 1 and 2 were, respectively, 75% and 50% for 9 Gy Multiplication-Sign 5, 100% and 100% for 10 Gy Multiplication-Sign 5, and 99% and 91% for 18 Gy Multiplication-Sign 3. Median overall survival was 14 months, not reached, and 34 months for the 9 Gy Multiplication-Sign 5, 10 Gy Multiplication-Sign 5, and 18 Gy Multiplication-Sign 3 treatments, respectively. No difference in local control or overall survival was found between the 10 Gy Multiplication-Sign 5 and 18 Gy Multiplication-Sign 3 groups on log-rank test, but both groups had improved local control and overall survival compared with 9 Gy Multiplication-Sign 5. Treatment with 9 Gy Multiplication-Sign 5 was the only independent prognostic factor for reduced local control on multivariate analysis, and increasing age, increasing tumor volume, and poor performance status predicted independently for reduced overall survival. Conclusion: Treatment regimens of 10 Gy Multiplication-Sign 5 and 18 Gy Multiplication-Sign 3 seem to be efficacious for lung cancer SBRT and provide superior local control and overall survival compared with 9 Gy Multiplication-Sign 5.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2013

Temporal Nodal Regression and Regional Control After Primary Radiation Therapy for N2-N3 Head-and-Neck Cancer Stratified by HPV Status

Purpose: To compare the temporal lymph node (LN) regression and regional control (RC) after primary chemoradiation therapy/radiation therapy in human papillomavirus-related [HPV(+)] versus human papillomavirus-unrelated [HPV(−)] head-and-neck cancer (HNC). Methods and Materials: All cases of N2-N3 HNC treated with radiation therapy/chemoradiation therapy between 2003 and 2009 were reviewed. Human papillomavirus status was ascertained by p16 staining on all available oropharyngeal cancers. Larynx/hypopharynx cancers were considered HPV(−). Initial radiologic complete nodal response (CR) (≤1.0 cm 8-12 weeks after treatment), ultimate LN resolution, and RC were compared between HPV(+) and HPV(−) HNC. Multivariate analysis identified outcome predictors. Results: A total of 257 HPV(+) and 236 HPV(−) HNCs were identified. The initial LN size was larger (mean, 2.9 cm vs 2.5 cm; P<.01) with a higher proportion of cystic LNs (38% vs 6%, P<.01) in HPV(+) versus HPV(−) HNC. CR was achieved is 125 HPV(+) HNCs (49%) and 129 HPV(−) HNCs (55%) (P=.18). The mean post treatment largest LN was 36% of the original size in the HPV(+) group and 41% in the HPV(−) group (P<.01). The actuarial LN resolution was similar in the HPV(+) and HPV(−) groups at 12 weeks (42% and 43%, respectively), but it was higher in the HPV(+) group than in the HPV(−) group at 36 weeks (90% vs 77%, P<.01). The median follow-up period was 3.6 years. The 3-year RC rate was higher in the HPV(−) CR cases versus non-CR cases (92% vs 63%, P<.01) but was not different in the HPV(+) CR cases versus non-CR cases (98% vs 92%, P=.14). On multivariate analysis, HPV(+) status predicted ultimate LN resolution (odds ratio, 1.4 [95% confidence interval, 1.1-1.7]; P<.01) and RC (hazard ratio, 0.3 [95% confidence interval 0.2-0.6]; P<.01). Conclusions: HPV(+) LNs involute more quickly than HPV(−) LNs but undergo a more prolonged process to eventual CR beyond the time of initial assessment at 8 to 12 weeks after treatment. Post radiation neck dissection is advisable for all non-CR HPV(−)/non-CR N3 HPV(+) cases, but it may be avoided for selected non-CR N2 HPV(+) cases with a significant LN involution if they can undergo continued imaging surveillance. The role of positron emission tomography for response assessment should be investigated.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2018

Visualizing Clustering and Uncertainty Analysis with Multivariate Longitudinal Data

Multivariate time-series datasets are intrinsic to the study of dynamic, naturalistic behavior, such as in the applications of finance and motion video analysis. Statistical models provide the ability to identify event patterns in these data under conditions of uncertainty, but researchers must be able to evaluate how well a model uses available information in a dataset for clustering decisions and for uncertainty information. The Hidden Markov Model (HMM) is an established method for clustering time-series data, where the hidden states of the HMM are the clusters. We develop novel methods for quantifying the uncertainty of the performance of and for visualizing the clustering performance and uncertainty of fitting a HMM to multivariate time-series data. We explain the usefulness of uncertainty quantification and visualization with evaluating the performance of clustering models, as well as how information exploitation of time-series datasets can be enhanced. We implement our methods to cluster patterns of scanpaths from raw eye tracking data.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2012

Influence of Radiofrequency Ablation of Lung Cancer on Pulmonary Function

Purpose: The purpose of this study was to evaluate altered pulmonary function retrospectively after RFA. Methods: This retrospective study comprised 41 ablation sessions for 39 patients (22 men and 17 women; mean age, 64.8 years). Vital capacity (VC) and forced expiratory volume in 1 s (FEV{sub 1}) at 1 and 3 months after RFA were compared with the baseline (i.e., values before RFA). To evaluate the factors that influenced impaired pulmonary function, univariate analysis was performed by using multiple variables. If two or more variables were indicated as statistically significant by univariate analysis, these variables were subjected to multivariate analysis to identify independent factors. Results: The mean VC and FEV{sub 1} before RFA and 1 and 3 months after RFA were 3.04 and 2.24 l, 2.79 and 2.11 l, and 2.85 and 2.13 l, respectively. The values at 1 and 3 months were significantly lower than the baseline. Severe pleuritis after RFA was identified as the independent factor influencing impaired VC at 1 month (P = 0.003). For impaired FEV{sub 1} at 1 month, only severe pleuritis (P = 0.01) was statistically significant by univariate analysis. At 3 months, severe pleuritis (VC, P = 0.019; FEV{sub 1}, P = 0.003) and an ablated parenchymal volume {>=}20 cm{sup 3} (VC, P = 0.047; FEV{sub 1}, P = 0.038) were independent factors for impaired VC and FEV{sub 1}. Conclusions: Pulmonary function decreased after RFA. RFA-induced severe pleuritis and ablation of a large volume of marginal parenchyma were associated with impaired pulmonary function.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2013

Effects of Treatment Duration During Concomitant Chemoradiation Therapy for Cervical Cancer

Purpose: To determine whether extended treatment duration (TD) impacts in-field relapse and survival in the setting of concomitant chemoradiation therapy (CRT) for cervical cancer. Methods and Materials: A total of 480 consecutive cervical cancer patients treated with radiation therapy (RT) alone or concomitant CRT for curative intent were retrospectively analyzed. Relapse was defined as in-field with respect to external beam radiation therapy fields. The effects of TD on in-field relapse, disease-free survival (DFS), and overall survival (OS) rates were assessed continuously and categorically within the separate RT and CRT cohorts. Covariates included age, histology, stage, and cumulative dose to point A. In-field relapse, DFS, and OS rates were estimated with Kaplan-Meier analysis; comparisons used log–rank statistic. Multivariate analysis used the Cox proportional hazards model. Results: A total of 372 patients (RT n=206, CRT n=166) were evaluable, with a median follow-up for relapse-free patients of 4.2 years (RT 4.4 years, CRT 4.2 years; P=.807). Treatment duration was longer in the RT cohort (median 55 days; range 35-99 days) versus the CRT cohort (median 51 days; range 35-92 days) (P=.001). In the RT cohort, TD ≥62 days trended to significance for predicting inferior DFS (hazard ratio 1.42, 95% confidence interval 0.86-1.98, P=.086). However, in the CRT cohort, TD assessed continuously or categorically across multiple cutoff thresholds did not predict for in-field relapse, DFS, or OS. Conclusion: With RT alone, extended TD ≥62 days may adversely impact treatment efficacy. With the addition of concomitant chemotherapy to RT, however, extended TD has no effect on treatment efficacy.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2024

Upscaling Soil Organic Carbon Measurements at the Continental Scale Using Multivariate Clustering Analysis and Machine Learning

Abstract Estimates of soil organic carbon (SOC) stocks are essential for many environmental applications. However, significant inconsistencies exist in SOC stock estimates for the U.S. across current SOC maps. We propose a framework that combines unsupervised multivariate geographic clustering (MGC) and supervised Random Forests regression, improving SOC maps by capturing heterogeneous relationships with SOC drivers. We first used MGC to divide the U.S. into 20 SOC regions based on the similarity of covariates (soil biogeochemical, bioclimatic, biological, and physiographic variables). Subsequently, separate Random Forests models were trained for each SOC region, utilizing environmental covariates and SOC observations. Our estimated SOC stocks for the U.S. (52.6 ± 3.2 Pg for 0–30 cm and 108.3 ± 8.2 Pg for 0–100 cm depth) were within the range estimated by existing products like Harmonized World Soil Database, HWSD (46.7 Pg for 0–30 cm and 90.7 Pg for 0–100 cm depth) and SoilGrids 2.0 (45.7 Pg for 0–30 cm and 133.0 Pg for 0–100 cm depth). However, independent validation with soil profile data from the National Ecological Observatory Network showed that our approach ( R 2 = 0.51) outperformed the estimates obtained from Harmonized World Soil Database ( R 2 = 0.23) and SoilGrids 2.0 ( R 2 = 0.39) for the topsoil (0–30 cm). Uncertainty analysis (e.g., low representativeness and high coefficients of variation) identified regions requiring more measurements, such as Alaska and the deserts of the U.S. Southwest. Our approach effectively captures the heterogeneous relationships between widely available predictors and the current SOC baseline across regions, offering reliable SOC estimates at 1 km resolution for benchmarking Earth system models.

58 GEOSCIENCES↗
DOE OSTI2012

DNA Repair Biomarkers Predict Response to Neoadjuvant Chemoradiotherapy in Esophageal Cancer

Purpose: The addition of neoadjuvant chemoradiotherapy prior to surgical resection for esophageal cancer has improved clinical outcomes in some trials. Pathologic complete response (pCR) following neoadjuvant therapy is associated with better clinical outcome in these patients, but only 22% to 40% of patients achieve pCR. Because both chemotherapy and radiotherapy act by inducing DNA damage, we analyzed proteins selected from multiple DNA repair pathways, using quantitative immunohistochemistry coupled with a digital pathology platform, as possible biomarkers of treatment response and clinical outcome. Methods and Materials: We identified 79 patients diagnosed with esophageal cancer between October 1994 and September 2002, with biopsy tissue available, who underwent neoadjuvant chemoradiotherapy prior to surgery at the Massachusetts General Hospital and used their archived, formalin-fixed, paraffin-embedded biopsy samples to create tissue microarrays (TMA). TMA sections were stained using antibodies against proteins in various DNA repair pathways including XPF, FANCD2, PAR, MLH1, PARP1, and phosphorylated MAPKAP kinase 2 (pMK2). Stained TMA slides were evaluated using machine-based image analysis, and scoring incorporated both the intensity and the quantity of positive tumor nuclei. Biomarker scores and clinical data were assessed for correlations with clinical outcome. Results: Higher scores for MLH1 (p = 0.018) and lower scores for FANCD2 (p = 0.037) were associated with pathologic response to neoadjuvant chemoradiation on multivariable analysis. Staining of MLH1, PARP1, XPF, and PAR was associated with recurrence-free survival, and staining of PARP1 and FANCD2 was associated with overall survival on multivariable analysis. Conclusions: DNA repair proteins analyzed by immunohistochemistry may be useful as predictive markers for response to neoadjuvant chemoradiotherapy in patients with esophageal cancer. These results are hypothesis generating and need confirmation in an independent data set.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Does Breast Density Increase the Risk of Re-excision for Women with Breast Cancer Having Breast-Conservation Therapy?

Background: Women with dense breasts may have less-accurate preoperative evaluation of extent of disease, potentially affecting the achievement of negative margins. The goal of this study is to examine the association between breast density and re-excision rates in women having breast-conserving surgery for invasive breast cancer. Patients and Methods: Women with stage I/II invasive breast cancer treated with breast-conserving surgery between 1/1/2014 and 10/31/2014 were included. Breast density was assessed by two radiologists. The association between breast density and re-excision was examined using logistic regression. Results: Seven hundred and one women were included. Overall, 106 (15.1%) women had at least one re-excision. Younger age at diagnosis was associated with increased breast density (p < 0.001). On univariable analysis, increased breast density was associated with significantly increased odds of re-excision (odds ratio [OR] 1.38, 95% confidence interval [CI] 1.04–1.83), as was multifocal disease, human epidermal growth factor receptor 2 (HER2) positive status, and extensive intraductal component (EIC) (all p < 0.05). On multivariable analysis, breast density remained significantly associated with increased odds of re-excision (OR 1.37, 95% CI 1.00–1.86), as did multifocality and EIC. HER2 positive status was not significantly associated with re-excision on multivariable analysis. Conclusions: Women with dense breasts are more likely to need additional surgery (re-excision after breast-conserving surgery), but increased breast density did not adversely affect disease-free survival in our study. Our findings support the need for further study in developing techniques that can help decrease re-excisions for women with dense breasts who undergo breast-conserving surgery.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2013

Geant4 Model Validation of Compton Suppressed System for Process monitoring of Spent Fuel

Nuclear material accountancy is of continuous concern for the regulatory, safeguards, and verification communities. In particular, spent nuclear fuel reprocessing facilities pose one of the most difficult accountancy challenges: monitoring highly radioactive, fluid sample streams in near real-time. The Multi-Isotope Process monitor will allow for near-real-time indication of process alterations using passive gamma-ray detection coupled with multivariate analysis techniques to guard against potential material diversion or to enhance domestic process monitoring. The Compton continuum from the dominant 661.7 keV 137Cs fission product peak obscures lower energy lines which could be used for spectral and multivariate analysis. Compton suppression may be able to mitigate the challenges posed by the high continuum caused by scattering. A Monte Carlo simulation using the Geant4 toolkit is being developed to predict the expected suppressed spectrum from spent fuel samples to estimate the reduction in the Compton continuum. Despite the lack of timing information between decay events in the particle management of Geant4, encouraging results were recorded utilizing only the information within individual decays without accounting for accidental coincidences. The model has been validated with single and cascade decay emitters in two steps: as an unsuppressed system and with suppression activated. Results of the Geant4 model validation will be presented.

Bender, Sarah↗
DOE OSTI2019

Predictors and Cumulative Frequency of Hepatocellular Carcinoma in High and Intermediate LI-RADS Lesions: A Cohort Study from a Canadian Academic Institution

Background: The frequency and predictors of hepatocellular carcinoma (HCC) within each liver imaging reporting and data system (LI-RADS) category remains unclear. We sought to estimate the cumulative frequency of HCC in LI-RADS observations of high/intermediate category and identify clinical/radiographic features associated with HCC. Methods: Our diagnostic imaging database was searched for computed tomography/magnetic resonance imaging reports of patients with evidence of cirrhosis and liver observations. LI-RADS categories were determined by imaging review, while demographic and clinical outcomes were assigned by chart review. A composite outcome of clinical/radiographic confirmation of HCC was used. We used multivariable analysis to identify features associated with HCC, and competing risks regression to estimate the cumulative frequency of HCC in each category. Results: Our search returned 95 patients with 137 observations (LR2 = 4, LR3 = 53, LR4 = 37, and LR5 = 43). On multivariable analysis, increasing age (hazard ratio [HR] 1.76 per 10 years, p = 0.049), washout (HR 5.34, p < 0.002), and increasing size (size < 10 mm reference, 10–20 mm, HR 3.93, p = 0.014; size > 20 mm, HR 21.69, p < 0.001) were associated with HCC. Median time to diagnosis was 6.13 months (interquartile range [IQR] 4.6–13.1), 4.7 months (IQR 2.5–14.5), and 3.6 months (IQR 1.9–6.6) for LR3, 4, and 5 category observations, respectively. The cumulative frequency of HCC was 59.8% in LR3, 84.62% in LR4, and 99.84% in LR5, at last follow-up. Conclusion: The frequency of HCC within each LI-RADS category reflects the intended purpose, intermediate probability for LR3, probable HCC for LR4, and definite HCC for LR5.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Post-Mastectomy Radiotherapy After Neoadjuvant Chemotherapy in Breast Cancer: A Pooled Retrospective Analysis of Three Prospective Randomized Trials

Background: The impact of locoregional radiotherapy (RT) after neoadjuvant chemotherapy (NACT) and mastectomy in breast cancer patients is currently unclear. Several publications have suggested that patients with a favorable response to NACT might not benefit from RT after mastectomy. Methods: A retrospective analysis of three prospective randomized NACT trials was performed. Information on the use of RT was available for 817 breast cancer patients with non-inflammatory breast cancer who underwent mastectomy after NACT within the GeparTrio, GeparQuattro, and GeparQuinto-trials. RT was administered to 676 of these patients (82.7%). Results: The 5-year cumulative incidence of locoregional recurrence (LRR) was 15.2% (95% confidence interval [CI] 9.0–22.8%) in patients treated without RT and 11.3% in patients treated with RT (95% CI 8.7–14.3%). In the multivariate analysis, RT was associated with a lower risk of LRR (hazard ratio 0.51, 95% CI 0.27–1.0; p = 0.05). This effect was shown especially in patients with cT3/4 tumors, as well as in patients who were cN+ before neoadjuvant therapy, including those who converted to ypN0 after neoadjuvant therapy. In the bivariate analysis, disease-free survival was significantly worse in patients who received RT, however this was not confirmed in the multivariate analysis. Conclusions: Our results suggest that RT reduces the LRR rates in breast cancer patients who receive a mastectomy after NACT without an improvement in DFS. Prospective randomized controlled trials such as the National Surgical Adjuvant Breast and Bowel Project B-51/RTOG 1304 trial will analyze whether RT has any benefit in patients who have a favorable response after NACT.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Significance of {sup 18}F-Fluorodeoxyglucose (FDG) Uptake in Response to Chemoradiotherapy for Pancreatic Cancer

Background: A metabolic shift to glycolysis is reportedly involved in radioresistance. We examined whether pretreatment {sup 18}F-fluorodeoxyglucose positron emission tomography (FDG-PET), which can detect enhanced glucose uptake, was able to predict the therapeutic response to chemoradiotherapy (CRT) in patients with pancreatic cancer (PC). Methods: Of 125 PC patients (75 unresectable and 50 borderline resectable), 37 and 26 underwent induction chemotherapy before CRT and surgical resection after CRT, respectively. FDG-PET was performed at three different institutions. Results: Of the 88 patients who underwent upfront CRT, 31 (35%), 34 (39%), and 23 (26%) showed a partial response (PR), stable disease, and progressive disease, respectively. The tumor PR rate was an independent factor associated with longer overall survival (OS) on multivariate analysis. We evaluated the optimal cut-off of maximum standardized uptake values (SUV{sub max}) at initial diagnosis to detect the tumor PR rate at the three institutions separately. The SUV{sub max} was independently associated with tumor response rate on multivariate analysis. In the low SUV{sub max} group, induction chemotherapy had no significant impact on OS. In contrast, induction chemotherapy was significantly associated with longer OS in the high SUV{sub max} group. Conclusions: FDG-PET SUV{sub max} was significantly associated with the therapeutic response to CRT in PC patients. Moreover, induction chemotherapy may improve the prognosis of patients with a high SUV{sub max} tumor.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2014

Prostate-Specific Antigen at 4 to 5 Years After Low-Dose-Rate Prostate Brachytherapy Is a Strong Predictor of Disease-Free Survival

Purpose: To determine (1) the prognostic utility of prostate-specific antigen (PSA) concentration at 45 to 60 months (48mPSA) after low-dose-rate prostate brachytherapy (LDR-PB); (2) the predictors of 48mPSA; and (3) the prognostic utility of directional trends between PSA levels at 24, 36, and 48 months after LDR-PB. Methods and Materials: Between 1998 and 2008, 2223 patients with low- and intermediate-risk prostate cancer received LDR-PB monotherapy. A cohort of 1434 of these patients was identified with a documented 48mPSA and no evidence of disease relapse prior to the 48mPSA. In addition, a subset of this cohort (n=585) was identified with ≥72 months of follow-up and documented PSA values at both 24 and 36 months after implantation. Results: Median follow-up time was 76 months. Eight-year Kaplan-Meier disease-free survival (DFS) rates were 100% vs 73.4% for patients with 48mPSA ≤0.2 vs those with >0.2 ng/mL; 99.1% versus 53.8% for a 48mPSA threshold of ≤0.4 versus >0.4 ng/mL, respectively; and 97.3% versus 0% for a threshold of ≤1.0 versus >1.0 ng/mL, respectively. On multivariate analysis, the only factor predictive of DFS was 48mPSA (P<.0001). On subset analysis (n=585), 29 patients had a PSA rise (defined as >0.2 ng/mL) between 24 and 36 months, 24 patients had a rise between 36 and 48 months, and 11 patients had rises over both intervals. Failure rates in these patients were 52%, 79%, and 100%, respectively. On multivariate analysis, initial PSA, androgen deprivation therapy, and dose to 90% of the prostate significantly correlated with 48mPSA but together accounted for only ∼5% of its total variance. Conclusions: The 48mPSA after LDR-PB is highly predictive of long-term DFS. Patients with 48mPSA ≤0.4 ng/mL had a <1% risk of disease relapse at 8 years, whereas all patients with 48mPSA >1.0 ng/mL relapsed. Consecutive PSA rises of >0.2 ng/mL from 24 to 36 months and from 36 to 48 months were also highly predictive of subsequent failure.

62 RADIOLOGY AND NUCLEAR MEDICINE↗