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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 847 records · Page 47
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

WE-AB-202-04: Statistical Evaluation of Lung Function Using 4DCT Ventilation Imaging: Proton Therapy VS IMRT

Purpose: Variation in function of different lung regions has been ignored so far for conventional lung cancer treatment planning, which may lead to higher risk of radiation induced lung disease. 4DCT based lung ventilation imaging provides a novel yet convenient approach for lung functional imaging as 4DCT is taken as routine for lung cancer treatment. Our work aims to evaluate the impact of accounting for spatial heterogeneity in lung function using 4DCT based lung ventilation imaging for proton and IMRT plans. Methods: Six patients with advanced stage lung cancer of various tumor locations were retrospectively evaluated for the study. Proton and IMRT plans were designed following identical planning objective and constrains for each patient. Ventilation images were calculated from patients’ 4DCT using deformable image registration implemented by Velocity AI software based on Jacobian-metrics. Lung was delineated into two function level regions based on ventilation (low and high functional area). High functional region was defined as lung ventilation greater than 30%. Dose distribution and statistics in different lung function area was calculated for patients. Results: Variation in dosimetric statistics of different function lung region was observed between proton and IMRT plans. In all proton plans, high function lung regions receive lower maximum dose (100.2%–108.9%), compared with IMRT plans (106.4%–119.7%). Interestingly, three out of six proton plans gave higher mean dose by up to 2.2% than IMRT to high function lung region. Lower mean dose (lower by up to 14.1%) and maximum dose (lower by up to 9%) were observed in low function lung for proton plans. Conclusion: A systematic approach was developed to generate function lung ventilation imaging and use it to evaluate plans. This method hold great promise in function analysis of lung during planning. We are currently studying more subjects to evaluate this tool.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

SU-E-J-92: Validating Dose Uncertainty Estimates Produced by AUTODIRECT, An Automated Program to Evaluate Deformable Image Registration Accuracy

Purpose: Deformable image registration (DIR) is a powerful tool with the potential to deformably map dose from one computed-tomography (CT) image to another. Errors in the DIR, however, will produce errors in the transferred dose distribution. We have proposed a software tool, called AUTODIRECT (automated DIR evaluation of confidence tool), which predicts voxel-specific dose mapping errors on a patient-by-patient basis. This work validates the effectiveness of AUTODIRECT to predict dose mapping errors with virtual and physical phantom datasets. Methods: AUTODIRECT requires 4 inputs: moving and fixed CT images and two noise scans of a water phantom (for noise characterization). Then, AUTODIRECT uses algorithms to generate test deformations and applies them to the moving and fixed images (along with processing) to digitally create sets of test images, with known ground-truth deformations that are similar to the actual one. The clinical DIR algorithm is then applied to these test image sets (currently 4) . From these tests, AUTODIRECT generates spatial and dose uncertainty estimates for each image voxel based on a Student’s t distribution. This work compares these uncertainty estimates to the actual errors made by the Velocity Deformable Multi Pass algorithm on 11 virtual and 1 physical phantom datasets. Results: For 11 of the 12 tests, the predicted dose error distributions from AUTODIRECT are well matched to the actual error distributions within 1–6% for 10 virtual phantoms, and 9% for the physical phantom. For one of the cases though, the predictions underestimated the errors in the tail of the distribution. Conclusion: Overall, the AUTODIRECT algorithm performed well on the 12 phantom cases for Velocity and was shown to generate accurate estimates of dose warping uncertainty. AUTODIRECT is able to automatically generate patient-, organ- , and voxel-specific DIR uncertainty estimates. This ability would be useful for patient-specific DIR quality assurance.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

SU-E-J-80: A Comparative Analysis of MIM and Pinnacle Software for Adaptive Planning

Purpose: IMRT treatment is often administered with image guidance and small PTV margins. Change in body habitus such as weight loss and tumor response during the course of a treatment could be significant, thus warranting re-simulation and re-planning. Adaptive planning is challenging and places significant burden on the staff, as such some commercial vendors are now offering adaptive planning software to stream line the process of re-planning and dose accumulation between different CT data set. The purpose of this abstract is to compare the adaptive planning tools between Pinnacle version 9.8 and MIM 6.4 software. Methods: Head and Neck cases of previously treated patients that experienced anatomical changes during the course of their treatment were chosen for evaluation. The new CT data set from the re-simulation was imported to Pinnacle and MIM software. The dynamic planning tool in pinnacle was used to calculate the old plan with fixed MU setting on the new CT data. In MIM, the old CT was registered to the new data set, followed by a dose transformation to the new CT. The dose distribution to the PTV and critical structures from each software were analyzed and compared. Results: 9% difference was observed between the Global maximum doses reported by both software. Mean doses to organs at risk and PTV’s were within 6 % however pinnacle showed greater difference in PTV coverage change. Conclusion: MIM software adaptive planning corrects for geometrical changes without consideration for the effect of radiological path length on dose distribution; however Pinnacle corrects for both geometric and radiological effect on the dose distribution. Pinnacle gives a better estimate of the dosimetric impact due to anatomical changes.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

TH-AB-BRA-05: Lung Cannot Be Treated as Homogeneous in Radiation Transport Simulations in Magnetic Fields

Purpose: Magnetic fields in MRgRT are known to induce dose perturbations near lung-tissue interfaces. The goal of this study is to determine if the heterogeneous structure of the lung influences the dose distribution in a magnetic field. Method: The dose distribution from a 4 cm X 4 cm 6 MV photon beam in a 0, 0.6, or 1.5 T magnetic field in a homogeneous lung density (0.333 g/cm{sup 3}) geometry is compared to that in a heterogeneous segmented slab configuration. The heterogeneous phantom is composed of 2/3 water vapour and 1/3 liquid water such that the overall density of the lung regions in the two phantoms are equivalent. The EGSnrc DOSXYZnrc user code is used with a previously implemented magnetic field transport code. Results: For water vapour gap thickness of 2 mm, compared to the homogeneous lung case (which already exhibits significant dose perturbations in a magnetic field) differences as large as 12.3 ± 0.2 % are observed for a 0.6 T field and 9.3 ± 0.1 % for a 1.5 T field at the tissuelung interface, and on the order of several percent within the lung-like tissue region for both magnetic fields. Thicker gaps produced larger deviations while a gap thickness of 0.2 mm does not result in notable differences. Regardless of gap thickness, the heterogeneities had little effect on the 0 T simulations. Further, using smaller scoring regions revealed that dose averaging effects could obscure dose differences as large as 10 – 20 % within the heterogeneous structures of the lung-like media. Conclusions: This simple model demonstrates that media heterogeneities can play an important role in MRgRT dose distributions, and care must be taken in setting up any dose calculation in the lung in the presence of a magnetic field, especially for air regions larger than 2 mm.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

SU-E-T-341: DVH-Based Comparison of True 3D Measurements to a Delta4 System

Purpose: Delta4 dosimetric software can be used to calculate DVH-based metrics for patient-specific quality assurance from measurements made by a Delta4 QA device. This study investigates the effectiveness of a novel transform method that transposes measurements made with a full-density 3D dosimeter onto patient anatomy, enabling the calculation of DVHs. This allows for DVH comparisons from the transformed dose distribution, which are based on true 3D measurements, to those from the Delta4 system, which are based on semi-3D measurements and interpolation. Methods: A double-arc VMAT treatment for a head-and-neck case was delivered to a 1kg PRESAGE 3D dosimeter inserted into a polyurethane head phantom. The dosimeter was readout using an in-house optical-CT scanner to gather full-density 3D dosimetric data. The transform method is achieved by multiplication of the measured doses with a “transformation matrix” which accounts for heterogeneities and differences in geometry between the patient and the phantom. The transformation matrix is a voxel-by-voxel division of the patient planned dose by the phantom planned dose, both calculated in the treatment planning system (Eclipse). The transformed distribution was then overlaid on the patient CT data, enabling the calculation of DVHs. The same VMAT treatment was delivered to the Delta4 phantom and DVH data was calculated using its associated software. Results: The transformed dose distribution showed good agreement with calculated patient values, determined by similarity in dose profiles between the two distributions and a 3D gamma index passing rate of 94.87% for 3%/3mm criteria. For every structure contained within the dosimeter volume, the transformed DVHs demonstrated better agreement than the Delta4 DVHs, when compared to the values calculated in the treatment planning system. Conclusion: The coupled technique of full-density 3D dose measurements and the presented transform method enables clinical patient-specific quality assurance data that is more accurate than the semi-3D Delta4 system. This work was supported by NIH R01CA100835.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Estimation of Dose from Potential Radionuclide Emissions from the Sample Preparation Laboratory at the Materials and Fuels Complex

The Sample Preparation Laboratory (SPL) at the Materials and Fuels Complex will perform sample preparation, examination, and mechanical-property testing of highly irradiated materials. The purpose of this report is to document calculation of the estimated dose at public receptor locations from potential radionuclide releases to the atmosphere from SPL. Atmospheric dispersion and dose calculations were performed with the computer model CAP88-PC Version 4 in accordance with the requirements of Code of Federal Regulations (CFR), Title 40, “Protection of the Environment,” Part 61, “National Emission Standards for Hazardous Air Pollutants (NESHAPs),” Subpart H, “National Emission Standards for Emissions of Radionuclides Other than Radon from Department of Energy Facilities” (40 CFR 61, Subpart H 2010). Emission potentials were calculated based on the methodology in 40 CFR Part 61, Appendix D and additional guidance/approval by EPA Region 10 [see letter from Donald Dossett (EPA Region 10) to Tim Safford (DOE-ID), Oct 19, 2017 (CCN 241475)] for solid materials that undergo heating. Estimates of total effective dose are based on low-level chronic exposure. The potential maximum dose to a member of the public was calculated to be 0.02 mrem/year based on an estimated 16 g of the 30 kg source term (0.053%) being exposed to very high temperatures associated with electrical-discharge machining (EDM) and the remaining material heated to 100°C. Calculations show the maximum dose could be as high as 0.05 mrem/year if the remaining material were heated to 1400°C (i.e., the melting point of stainless steel). The potential maximum dose to a public receptor from emissions at SPL is not expected to exceed 0.1 mrem/year (1% of the standard) so long as the material impacted by EDM does not exceed 56 g (3.5 times the expected mass of 16 g and less than 0.2% of the total source term), and the remaining material is not heated to temperatures greater than 1400°C. It should be noted that credit for HEPA filtration does not impact the dose results because the dose is dominated by radionuclides that have exceeded their boiling point; thus, no credit for HEPA filtration may be applied to the emission factor.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2011

A self-adaptive case-based reasoning system for dose planning in prostate cancer radiotherapy

Purpose: Prostate cancer is the most common cancer in the male population. Radiotherapy is often used in the treatment for prostate cancer. In radiotherapy treatment, the oncologist makes a trade-off between the risk and benefit of the radiation, i.e., the task is to deliver a high dose to the prostate cancer cells and minimize side effects of the treatment. The aim of our research is to develop a software system that will assist the oncologist in planning new treatments. Methods: A nonlinear case-based reasoning system is developed to capture the expertise and experience of oncologists in treating previous patients. Importance (weights) of different clinical parameters in the dose planning is determined by the oncologist based on their past experience, and is highly subjective. The weights are usually fixed in the system. In this research, the weights are updated automatically each time after generating a treatment plan for a new patient using a group based simulated annealing approach. Results: The developed approach is analyzed on the real data set collected from the Nottingham University Hospitals NHS Trust, City Hospital Campus, UK. Extensive experiments show that the dose plan suggested by the proposed method is coherent with the dose plan prescribed by an experienced oncologist or even better. Conclusions: The developed case-based reasoning system enables the use of knowledge and experience gained by the oncologist in treating new patients. This system may play a vital role to assist the oncologist in making a better decision in less computational time; it utilizes the success rate of the previously treated patients and it can also be used in teaching and training processes.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2010

Enhanced epidermal dose caused by localized electron contamination from lead cutouts used in kilovoltage radiotherapy

Purpose: To investigate and quantify electron contamination from the lead cutouts used in kilovoltage x-ray radiotherapy. Methods: The lead cutouts were modeled with the Monte Carlo EGSnrc user codes DOSXYZnrc and DOSRZnrc for x-ray beams ranging from 50 to 300 kV{sub p}. The results from the model were confirmed with Gafchromic film measurements. The model and measurements investigated the dose distribution with and without gladwrap shielding under the lead, and dose distributions with round, square, and serrated edge cutouts. Results: Large dose enhancement near the edges of the lead was observed due to electron contamination. At the epidermal/dermal border, there is double the dose at the edge of the lead compared to the central dose due to electron contamination for a 150 kV{sub p} beam and three times the dose for a 300 kV{sub p} beam. gladwrap shielding effectively removes the contaminant dose enhancement using ten and four layers for 300 and 150 kV{sub p} beams, respectively. Conclusions: The contaminant dose enhancement is undesirable as it could cause unnecessary erythema and hyperpigmentation at the border of the treated and untreated skin and lead to a poorer cosmetic outcome. The contamination is easily removed by gladwrap shielding placed under or around the lead cutout.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2011

Characteristics of the Neutron Irradiation Facilities of the PSI Calibration Laboratory

The neutron radiation fields of the Calibration Laboratory at Paul Scherrer Institute (PSI) are traceable to the national standards of the Physikalisch-Technische Bundesanstalt (PTB) in Germany. A Berthold LB6411 neutron dose rate meter for neutron radiation is used as a secondary standard. Recently, a thorough characterization of the neutron irradiation fields of the {sup 241}Am-Be and {sup 252}Cf sources by means of reference measurements and a detailed MCNPX simulation of the irradiation facility has been initiated. In this work, the characteristics of the neutron radiation fields are summarized and presented together with model equations and an uncertainty analysis. MCNPX results are shown for the {sup 241}Am-Be source. A comparison of measured and simulated data shows an excellent agreement. From the simulation, valuable information about the neutron fields like the contribution of scattered neutrons in the fields and the energy spectra could be obtained.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2012

Development and optimization of a beam shaper device for a mobile dedicated IOERT accelerator

Purpose: The aim of this study was to design and build a prototype beam shaper to be used on a dedicated mobile accelerator that protects organs at risk within the radiation field and conforms the beam to the target geometry during intraoperative electron radiotherapy (IOERT). A dosimetric characterization of the beam shaper device was performed based on Monte Carlo (MC) simulations, as well as experimental data, at different energies, field sizes, and source to skin distances. Methods: A mobile light intraoperative accelerator (LIAC{sup Registered-Sign }, Sordina, Italy) was used. The design of the beam shaper prototype was based on MC simulations (BEAMnrc/OMEGA and DOSXYZnrc code) for a selection of materials and thicknesses, as well as for dosimetric characterization. Percentage depth dose (PDD) and profile measurements were performed using a p-type silicon diode and a commercial water phantom, while output factors were measured using a PinPoint ion chamber in a PMMA phantom. Planar doses in planes of interest were carried out using radiochromic films (Gafchromic{sup TM} EBT and EBT2) in PMMA and in a Solid Water{sup Registered-Sign} phantom. Several experimental set-ups were investigated with the beam shaper device fixed on the top of the phantom, varying both the short side of the rectangular field and the air gap between the device and the phantom surface, simulating the clinical situation. The output factors (OFs) were determined using different geometrical set-ups and energies. Results: The beam shaper prototype consists of four blades sliding alongside each other and mounted on a special support at the end of the 10 cm diameter PMMA circular applicator. Each blade is made of an upper layer of 2.6 cm of Teflon{sup Registered-Sign} and a lower layer of 8 mm of stainless steel. All rectangles inscribed in a 5 cm diameter can be achieved in addition to any 'squircle-shaped' field. When one side of the rectangular field is held constant and the second side is reduced, both R{sub 50} and R{sub max} move towards the phantom surface. Comparing the PDDs obtained with the 5 cm circular applicator and with a 4.4 Multiplication-Sign 4.4 cm{sup 2} square field (that is the equivalent square of the 5 cm circular field) obtained with the beam shaper, a different behavior was observed in the region extending from the surface to a depth of 50% of the maximum dose. Isodoses measured for rectangular fields used for clinical cases (i.e., 4 Multiplication-Sign 9 cm{sup 2} 8 MeV) are shown, with different air gaps. For each energy investigated, the normalized OFs slowly increase, when the length of the side decreases down to about 4 cm, and then rapidly decreases for smaller field widths. MC simulation showed an excellent agreement with experimental data (<2%). Conclusions: The beam shaper device is able to provide square/rectangular/squircle fields with adequate dose homogeneity for mobile dedicated accelerators, thus allowing conformal treatment with IOERT. Monte Carlo simulation can be a very useful tool to simulate any clinical set up and can be used to create a data set to calculate MUs, thereby increasing the accuracy of the delivered dose during IOERT procedures.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2015

SU-E-T-507: Internal Dosimetry in Nuclear Medicine Using GATE and XCAT Phantom: A Simulation Study

Purpose Monte Carlo simulations are routinely used for internal dosimetry studies. These studies are conducted with humanoid phantoms such as the XCAT phantom. In this abstract we present the absorbed doses for various pairs of source and target organs using three common radiotracers in nuclear medicine. Methods The GATE software package is used for the Monte Carlo simulations. A typical female XCAT phantom is used as the input. Three radiotracers 153Sm, 131I and 99mTc are studied. The Specific Absorbed Fraction (SAF) for gamma rays (99mTc, 153Sm and 131I) and Specific Fraction (SF) for beta particles (153Sm and 131I) are calculated for all 100 pairs of source target organs including brain, liver, lung, pancreas, kidney, adrenal, spleen, rib bone, bladder and ovaries. Results The source organs themselves gain the highest absorbed dose as compared to other organs. The dose is found to be inversely proportional to distance from the source organ. In SAF results of 153Sm, when the source organ is lung, the rib bone, gain 0.0730 (Kg-1) that is more than lung itself. Conclusion The absorbed dose for various organs was studied in terms of SAF and SF. Such studies hold importance for future therapeutic procedures and optimization of induced radiotracer.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

Thermal safety of ultrasound-enhanced ocular drug delivery: A modeling study

Purpose: Delivery of sufficient amounts of therapeutic drugs into the eye for treatment of various ocular diseases is often a challenging task. Ultrasound was shown to be effective in enhancing ocular drug delivery in the authors’ previous in vitro and in vivo studies. Methods: The study reported here was designed to investigate the safety of ultrasound application and its potential thermal effects in the eye using PZFlex modeling software. The safety limit in this study was set as a temperature increase of no more than 1.5 °C based on regulatory recommendations and previous experimental safety studies. Acoustic and thermal specifications of different human eye tissues were obtained from the published literature. The tissues of particular interest in this modeling safety study were cornea, lens, and the location of optic nerve in the posterior eye. Ultrasound application was modeled at frequencies of 400 kHz–1 MHz, intensities of 0.3–1 W/cm{sup 2}, and exposure duration of 5 min, which were the parameters used in the authors’ previous drug delivery experiments. The baseline eye temperature was 37 °C. Results: The authors’ results showed that the maximal tissue temperatures after 5 min of ultrasound application were 38, 39, 39.5, and 40 °C in the cornea, 39.5, 40, 42, and 43 °C in the center of the lens, and 37.5, 38.5, and 39 °C in the back of the eye (at the optic nerve location) at frequencies of 400, 600, 800 kHz, and 1 MHz, respectively. Conclusions: The ocular temperatures reached at higher frequencies were considered unsafe based on current recommendations. At a frequency of 400 kHz and intensity of 0.8 W/cm{sup 2} (parameters shown in the authors’ previous in vivo studies to be optimal for ocular drug delivery), the temperature increase was small enough to be considered safe inside different ocular tissues. However, the impact of orbital bone and tissue perfusion should be included in future modeling efforts to determine the safety of this method in the whole orbit especially regarding potential adverse optic nerve heating at the location of the bone.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

MO-AB-204-02: IHE RAD [Health care]

You’ve experienced the frustration: vendor A’s device claims to work with vendor B’s device, but the practice doesn’t match the promise. Getting devices working together is the hidden art that Radiology and Radiation Oncology staff have to master. To assist with that difficult process, the Integrating the Healthcare Enterprise (IHE) effort was established in 1998, with the coordination of the Radiological Society of North America. Integrating the Healthcare Enterprise (IHE) is a consortium of healthcare professionals and industry partners focused on improving the way computer systems interconnect and exchange information. This is done by coordinating the use of published standards like DICOM and HL7. Several clinical and operational IHE domains exist in the healthcare arena, including Radiology and Radiation Oncology. The ASTRO-sponsored IHE Radiation Oncology (IHE-RO) domain focuses on radiation oncology specific information exchange. This session will explore the IHE Radiology and IHE RO process for; IHE solicitation process for new profiles. Improving the way computer systems interconnect and exchange information in the healthcare enterprise Supporting interconnectivity descriptions and proof of adherence by vendors Testing and assuring the vendor solutions to connectivity problems. Including IHE profiles in RFPs for future software and hardware purchases. Learning Objectives: Understand IHE role in improving interoperability in health care. Understand process of profile development and implantation. Understand how vendors prove adherence to IHE RO profiles. S. Hadley, ASTRO Supported Activity.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

WE-H-BRA-08: A Monte Carlo Cell Nucleus Model for Assessing Cell Survival Probability Based On Particle Track Structure Analysis

Purpose: To correlate the damage produced by particles of different types and qualities to cell survival on the basis of nanodosimetric analysis and advanced DNA structures in the cell nucleus. Methods: A Monte Carlo code was developed to simulate subnuclear DNA chromatin fibers (CFs) of 30nm utilizing a mean-free-path approach common to radiation transport. The cell nucleus was modeled as a spherical region containing 6000 chromatin-dense domains (CDs) of 400nm diameter, with additional CFs modeled in a sparser interchromatin region. The Geant4-DNA code was utilized to produce a particle track database representing various particles at different energies and dose quantities. These tracks were used to stochastically position the DNA structures based on their mean free path to interaction with CFs. Excitation and ionization events intersecting CFs were analyzed using the DBSCAN clustering algorithm for assessment of the likelihood of producing DSBs. Simulated DSBs were then assessed based on their proximity to one another for a probability of inducing cell death. Results: Variations in energy deposition to chromatin fibers match expectations based on differences in particle track structure. The quality of damage to CFs based on different particle types indicate more severe damage by high-LET radiation than low-LET radiation of identical particles. In addition, the model indicates more severe damage by protons than of alpha particles of same LET, which is consistent with differences in their track structure. Cell survival curves have been produced showing the L-Q behavior of sparsely ionizing radiation. Conclusion: Initial results indicate the feasibility of producing cell survival curves based on the Monte Carlo cell nucleus method. Accurate correlation between simulated DNA damage to cell survival on the basis of nanodosimetric analysis can provide insight into the biological responses to various radiation types. Current efforts are directed at producing cell survival curves for high-LET radiation.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2010

ISDD: A Computational Model of Particle Sedimentation, Diffusion and Target Cell Dosimetry for In Vitro Toxicity Studies

Background: The difficulty of directly measuring cellular dose is a significant obstacle to application of target tissue dosimetry for nanoparticle and microparticle toxicity assessment. As a consequence, the target tissue paradigm for dosimetry and hazard assessment of nanoparticles has largely been ignored in favor of using metrics of exposure (e.g. μg particle/mL culture medium, particle surface area/mL, particle number/mL). We have developed a computational model of solution particokinetics (sedimentation, diffusion) and dosimetry for non-interacting spherical particles and their agglomerates in monolayer cell culture systems. Particle transport to cells is calculated by simultaneous solution of Stokes Law (sedimentation) and the Stokes-Einstein equation (diffusion). Results: The In vitro Sedimentation, Diffusion and Dosimetry model (ISDD) was tested against measured transport rates or cellular doses for multiple sizes of polystyrene spheres (20-1100 nm), 35 nm amorphous silica, and large agglomerates of 30 nm iron oxide particles. Overall, without adjusting any parameters, model predicted doses were in close agreement with the experimental data, differing from as little as 5% to as much as three-fold, but in most cases approximately two-fold, within the limits of the accuracy of the measurement systems. Applying the model, we generalize the effects of particle size, particle density, agglomeration state and agglomerate characteristics on target cell dosimetry in vitro. Conclusions: Our results confirm our hypothesis that the dose-rates for all particles are not equal, but can vary significantly, in direct contrast to the assumption of dose-equivalency implicit in the use of mass-based media concentrations as metrics of exposure for dose-response assessment. The difference between equivalent nominal media concentration exposures on a μg/mL basis and target cell doses on a particle surface area or number basis can be as high as three to six orders of magnitude. As a consequence, in vitro hazard assessments utilizing mass-based exposure metrics have inherently high errors where particle number or surface areas target cells doses are believed to drive response. The gold standard for particle dosimetry for in vitro nanotoxicology studies should be direct experimental measurement of the cellular content of the studied particle. However, where such measurements are impractical, unfeasible, and before such measurements become common, particle dosimetry models such as ISDD provide a valuable, immediately useful alternative, and eventually an adjunct to such measurements.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2011

Assessment of Unabated Facility Emission Potentials for Evaluating Airborne Radionuclide Monitoring Requirements at Pacific Northwest National Laboratory - 2010

Assessments were performed to evaluate compliance with the airborne radionuclide emission monitoring requirements in the National Emission Standards for Hazardous Air Pollutants ([NESHAP]; U.S. Code of Federal Regulations, Title 40, Part 61, Subpart H) and Washington Administrative Code 246-247: Radiation Protection - Air Emissions. In these NESHAP assessments, potential unabated off-site doses were evaluated for emission locations at buildings that are part of the consolidated laboratory campus of the Pacific Northwest National Laboratory. This report describes the inventory-based methods and provides the results for the NESHAP assessment performed in 2010.

Air Monitoring↗
DOE OSTI2017

Marine Sciences Laboratory Radionuclide Air Emissions

The U.S. Department of Energy Office of Science (DOE-SC) Pacific Northwest Site Office has oversight and stewardship duties associated with the Pacific Northwest National Laboratory Marine Sciences Laboratory (MSL), located on Battelle Land-Sequim. The facility has two buildings with the potential to emit low levels of radioactive materials. DOE-SC contracted for exclusive use of its radiological operations effective October 1, 2012. This report is prepared to document compliance with the Code of Federal Regulation, Title 40, Protection of the Environment, Part 61, National Emission Standards for Hazardous Air Pollutants , Subpart H, “National Emission Standards for Emissions of Radionuclides Other than Radon from Department of Energy Facilities” and Washington Administrative Code Chapter 246-247, Radiation Protection–Air Emissions . Compliance is indicated by comparing the estimated effective dose equivalent (EDE) to the maximally exposed individual (MEI) with the 10 millirem per year (mrem/yr) U.S. Environmental Protection Agency (EPA) standard. The MSL has only fugitive emissions sources. Despite the fact that the regulations are intended for application to point source emissions, fugitive emissions are included with regard to complying with the EPA standard. The EDE to the MSL MEI due to routine operations in 2016 was 5.7E-04 mrem (5.7E-06 mSv). No non-routine emissions occurred in 2016. The MSL is in compliance with the federal and state 10 mrem/yr standard.

40 CFR 61 Subpart H↗
DOE OSTI2018

Marine Sciences Laboratory Radionuclide Air Emissions Report for Calendar Year 2017

The U.S. Department of Energy Office of Science (DOE-SC) Pacific Northwest Site Office has oversight and stewardship duties associated with the Pacific Northwest National Laboratory Marine Sciences Laboratory (MSL), located on Battelle Land-Sequim. The facility has two buildings with the potential to emit low levels of radioactive materials. This report is prepared to document compliance with the Code of Federal Regulation, Title 40, Protection of the Environment, Part 61, National Emission Standards for Hazardous Air Pollutants, Subpart H, “National Emission Standards for Emissions of Radionuclides Other than Radon from Department of Energy Facilities” and Washington Administrative Code Chapter 246-247, Radiation Protection–Air Emissions. Compliance is indicated by comparing the estimated effective dose equivalent (EDE) to the maximally exposed individual (MEI) with the 10 millirem per year (mrem/yr) U.S. Environmental Protection Agency (EPA) standard. The MSL has only fugitive emissions sources. Despite the fact that the regulations are intended for application to point source emissions, fugitive emissions are included with regard to complying with the EPA standard. The EDE to the MSL MEI due to routine operations in 2017 was 1.6E-04 mrem (1.6E-06 mSv). No non-routine emissions occurred in 2017. The MSL is in compliance with the federal and state 10 mrem/yr standard.

40 CFR 61 Subpart H↗