bluuebunny/crossref_metadata_2025 huggingface dataset:
Isolation of protein complexes from the model legume Medicago truncatula by tandem affinity purification in hairy root cultures
Authors: Goossens Jonas , De Geyter Nathan , Walton Alan , Eeckhout Dominique , Mertens Jan , Pollier Jacob , Fiallos‐Jurado Jennifer , De Keyser Annick , De Clercq Rebecca , Van Leene Jelle , Gevaert Kris , De Jaeger Geert , Goormachtig Sofie , Goossens Alain
Published: July 2016

Tandem affinity purification coupled to mass spectrometry (TAP‐MS) is one of the most powerful techniques to isolate protein complexes and elucidate protein interaction networks. Here, we describe the development of a TAP‐MS strategy for the model legume Medicago truncatula, which is widely studied for its ability to produce valuable natural products and to engage in endosymbiotic interactions. As biological material, transgenic hairy roots, generated through Agrobacterium rhizogenes‐mediated transformation of M. truncatula seedlings, were used. As proof of concept, proteins involved in the cell cycle, transcript processing and jasmonate signalling were chosen as bait proteins, resulting in a list of putative interactors, many of which confirm the interologue concept of protein interactions, and which can contribute to biological information about the functioning of these bait proteins in planta. Subsequently, binary protein–protein interactions among baits and preys, and among preys were confirmed by a systematic yeast two‐hybrid screen. Together, by establishing a M. truncatula TAP‐MS platform, we extended the molecular toolbox of this model species.
Canine eosinophilic granuloma of the digits treated with prednisolone and chlorambucil
Authors: Knight Evie C. , Shipstone Michael A.
Published: July 2016

Background

Canine eosinophilic granuloma (CEG) is an uncommon disease. Lesions are typically located in the oral cavity and other cutaneous sites, but are rarely reported to affect the digits. The majority of cases are treated with prednisolone as a monotherapy; alternative treatment options include corticosteroids administered in combination with azathioprine, antihistamines, electrochemotherapy with bleomycin, and surgical resection. Neither chlorambucil nor laser previously have been reported as treatments.

Objectives

To describe an alternative therapy for treatment of CEG; using chlorambucil in combination with prednisolone for those cases that fail to respond to prednisolone alone. The new treatment was chosen according to good clinical practice and after owner consent.

Animals

Two client owned dogs.

Methods

One case was initially treated with carbon dioxide laser to debulk the lesions. Both cases were treated with a combination of oral prednisolone and chlorambucil.

Results

Both dogs experienced rapid resolution of lesions with prednisolone and chlorambucil therapy. Case 1 remained in remission three months after withdrawing medication. Case 2 experienced relapse 10 weeks after discontinuing therapy but was well controlled on maintenance prednisolone with chlorambucil at low, well tolerated doses.

Conclusions and clinical importance

Although CEG appears to be an uncommon disease, it should be included as a differential diagnosis for dermal, nodular lesions affecting the digits. Chlorambucil appears to be an effective and well tolerated prednisolone sparing agent for treatment of CEG. Carbon dioxide laser ablation appears to be an effective method of debulking CEGs.
SAFETY AND TOXICITY OF AN ACCELERATED COARSELY FRACTIONATED RADIATION PROTOCOL FOR TREATMENT OF APPENDICULAR OSTEOSARCOMA IN 14 DOGS: 10 GY × 2 FRACTIONS
Authors: Pagano Candace , Boudreaux Bonnie , Shiomitsu Keijiro
Published: July 2016

Coarsely fractionated radiation is commonly used as a method for pain control in dogs with appendicular osteosarcoma, however there is little published information on optimal protocols. The aim of this retrospective, descriptive study was to report safety and toxicity findings in a sample of dogs with appendicular osteosarcoma that had been treated with a radiation scheme of 10 Gy delivered over two consecutive days for a total of 20 Gy. Dogs were included in the study if they had osteosarcoma that was treated with the aforementioned protocol. Dogs were excluded if treated with the same protocol for any other bone tumor besides osteosarcoma or inadequate follow‐up. Thirteen of the 14 patients received adjuvant therapy with pamidronate and a nonsteroidal anti‐inflammatory. Nine dogs received adjuvant chemotherapy with carboplatin after radiation was complete. Within a median of 14 days, 92.8% of dogs subjectively had improved pain control. Median duration of response (DOR) was 80 days (range 20–365). The majority of patients developed VRTOG grade one toxicity, primarily alopecia. Five dogs (35.7%) developed pathologic fracture postradiation treatment. Timing of fracture was variable ranging from 24 to 250 days. This radiation protocol was well tolerated, with minimal toxicity, subjectively improved survival time, and had the benefit of being completed in two consecutive days.
EX VIVO CORRELATION OF ULTRASONOGRAPHIC SMALL INTESTINAL WALL LAYERING WITH HISTOLOGY IN DOGS
Authors: Le Roux Alexandre B. , Granger L. Abbigail , Wakamatsu Nobuko , Kearney Michael T. , Gaschen Lorrie
Published: July 2016

Canine ultrasonographic intestinal layers have been reported to correlate with histological layering. However, discrepancies have been reported in people, and additional layers visualized. The aim of this method comparison study was to describe ex vivo canine small intestinal layering and correlate it with histology. Small intestinal samples of 12 adult dogs euthanized for reasons unrelated to gastrointestinal disease were resected immediately following euthanasia, pinned on a Petri dish, and transverse ultrasonographic images acquired in a water bath, using a high‐frequency linear transducer. Transverse histological sections were obtained at the same level. Measurements of the intestinal layers were performed on the ultrasonographic and histological images. No significant statistical differences were noted between the ultrasonographic and histological measurements and strong to very strong (r > 0.7) positive correlation was observed for all layers, except for the serosa, which had a low moderate positive correlation (r = 0.479). In addition to the five established layers, a dual mucosal echogenicity was consistently observed, with seven samples presenting an additional inner mucosal severe hyperechogenicity. Histologically, this dual echogenicity was attributed to the intestinal villi (mildly echogenic) and lamina propria (hypoechoic). The additional inner mucosal severe hyperechogenicity observed in seven samples was attributed to mild‐to‐moderate lacteal dilation histologically. In 4/12 ileal samples, an additional hyperechoic mucosal line was also observed parallel to the submucosa, corresponding histologically to prominent Peyer's patches. Finally, a hyperechoic line was observed within the muscularis of all samples, corresponding histologically to the interface between the muscularis longitudinal and circular layers.
The splanchnic anti‐inflammatory pathway: could it be the efferent arm of the inflammatory reflex?
Authors: Martelli D. , Farmer D. G. S. , Yao S. T.
Published: July 2016

New Findings

What is the topic of this review?

We review the current literature on the neural reflex termed the ‘inflammatory reflex’ that inhibits an excessive release of inflammatory mediators in response to an immune challenge.

What advances does it highlight?

The original model proposed that the inflammatory reflex is a vago‐vagal reflex that controls immune function. We posit that, in the endotoxaemic animal model, the vagus nerves do not appear to play a role. The evidence suggests that the efferent motor pathway, termed here the ‘splanchnic anti‐inflammatory pathway’, is purely sympathetic, travelling via the greater splanchnic nerves to regulate the ensuing inflammatory response to immune challenges.

Exposure to immune challenges results in the development of inflammation. An insufficient inflammatory response can be life‐threatening, whereas an exaggerated response is also detrimental because it causes tissue damage and, in extreme cases, septic shock that can lead to death. Hence, inflammation must be finely regulated. It is generally accepted that the brain inhibits inflammation induced by an immune challenge in two main ways: humorally, by activating the hypothalamic–pituitary–adrenal axis to release glucocorticoids; and neurally, via a mechanism that has been termed the ‘inflammatory reflex’. The efferent arm of this reflex (the neural‐to‐immune link) was thought to be the ‘cholinergic anti‐inflammatory pathway’. Here, we discuss data that support the hypothesis that the vagus nerves play no role in the control of inflammation in the endotoxaemic animal model. We have shown and posit that it is the greater splanchnic nerves that are activated in response to the immune challenge and that, in turn, drive postganglionic sympathetic neurons to inhibit inflammation.
Parallel processing of afferent olfactory sensory information
Authors: Vaaga Christopher E. , Westbrook Gary L.
Published: July 2016

Key points

The functional synaptic connectivity between olfactory receptor neurons and principal cells within the olfactory bulb is not well understood.

One view suggests that mitral cells, the primary output neuron of the olfactory bulb, are solely activated by feedforward excitation.

Using focal, single glomerular stimulation, we demonstrate that mitral cells receive direct, monosynaptic input from olfactory receptor neurons.

Compared to external tufted cells, mitral cells have a prolonged afferent‐evoked EPSC, which serves to amplify the synaptic input.

The properties of presynaptic glutamate release from olfactory receptor neurons are similar between mitral and external tufted cells.

Our data suggest that afferent input enters the olfactory bulb in a parallel fashion.

Primary olfactory receptor neurons terminate in anatomically and functionally discrete cortical modules known as olfactory bulb glomeruli. The synaptic connectivity and postsynaptic responses of mitral and external tufted cells within the glomerulus may involve both direct and indirect components. For example, it has been suggested that sensory input to mitral cells is indirect through feedforward excitation from external tufted cells. We also observed feedforward excitation of mitral cells with weak stimulation of the olfactory nerve layer; however, focal stimulation of an axon bundle entering an individual glomerulus revealed that mitral cells receive monosynaptic afferent inputs. Although external tufted cells had a 4.1‐fold larger peak EPSC amplitude, integration of the evoked currents showed that the synaptic charge was 5‐fold larger in mitral cells, reflecting the prolonged response in mitral cells. Presynaptic afferents onto mitral and external tufted cells had similar quantal amplitude and release probability, suggesting that the larger peak EPSC in external tufted cells was the result of more synaptic contacts. The results of the present study indicate that the monosynaptic afferent input to mitral cells depends on the strength of odorant stimulation. The enhanced spiking that we observed in response to brief afferent input provides a mechanism for amplifying sensory information and contrasts with the transient response in external tufted cells. These parallel input paths may have discrete functions in processing olfactory sensory input.
On Calculating Heat Transfer and Pressure Drop of Supercritical-Pressure Coolants
Authors: Kurganov Vladimir A. , Zeigarnik Yuri A. , Maslakova Irina V.
Published: July 2016

Specific features of thermophysical properties of single-phase supercritical-pressure (SCP) coolants and typical ranges of their thermodynamic state that determine heat-transfer regularities are presented. A brief analysis of the existing concepts on SCP-coolants heat transfer under turbulent flow in tube is given. Typical features of normal and deteriorated heat-transfer regimes are described. The simple classification of deteriorated heat-transfer regimes at high heat loads that make it possible to distinguish the causes and appraise a degree of heat-transfer deterioration danger is proposed. The results from the studies of the hydraulic-resistance structure under the regimes of normal and deteriorated heat transfer are considered and the conditions, when a one-dimensional (1-D) (homogeneous) flow model can be used in hydraulic calculations, are revealed. Using sounding measurements data, the interrelation between heat-transfer deterioration and radical changes in the averaged turbulent flow structure due to fluid thermal acceleration and Archimedes forces effects is analyzed. The recommendations on calculating normal heat transfer with an account of refined standards on thermophysical properties of water and carbon dioxide are presented. The review and analysis of the existing criteria for forecasting heat-transfer deterioration and assessing the boundaries of the normal heat-transfer range are given, and the correlations for describing deteriorated heat transfer are presented.
Computational Fluid Dynamics Investigation of Supercritical Water Flow and Heat Transfer in a Rod Bundle With Grid Spacers
Authors: Gradecka Malwina , Thiele Roman , Anglart Henryk
Published: July 2016

This paper presents a steady-state computational fluid dynamics approach to supercritical water flow and heat transfer in a rod bundle with grid spacers. The current model was developed using the ANSYS Workbench 15.0 software (CFX solver) and was first applied to supercritical water flow and heat transfer in circular tubes. The predicted wall temperature was in good agreement with the measured data. Next, a similar approach was used to investigate three-dimensional (3D) vertical upward flow of water at supercritical pressure of about 25 MPa in a rod bundle with grid spacers. This work aimed at understanding thermo- and hydrodynamic behavior of fluid flow in a complex geometry at specified boundary conditions. The modeled geometry consisted of a 1.5-m heated section in the rod bundle, a 0.2-m nonheated inlet section, and five grid spacers. The computational mesh was prepared using two cell types. The sections of the rods with spacers were meshed using tetrahedral cells due to the complex geometry of the spacer, whereas sections without spacers were meshed with hexahedral cells resulting in a total of 28 million cells. Three different sets of experimental conditions were investigated in this study: a nonheated case and two heated cases. The nonheated case, A1, is calculated to extract the pressure drop across the rod bundle. For cases B1 and B2, a heat flux is applied on the surface of the rods causing a rise in fluid temperature along the bundle. While the temperature of the fluid increases along with the flow, heat deterioration effects can be present near the heated surface. Outputs from both B cases are temperatures at preselected locations on the rods surfaces.
Experimental and Numerical Study of Supercritical Carbon Dioxide Flow Through Valves
Authors: Yuan Haomin , Anderson Mark
Published: July 2016

The supercritical carbon dioxide (sCO2) Brayton cycle shows advantages such as high efficiency, compactness, and low capital cost. These benefits make it a competitive candidate for future-generation power-conversion cycles. In order to study this cycle, valve characteristics under sCO2 flow conditions must be studied. However, the traditional models for valves may not be accurate due to the real gas property of sCO2. In this study, this problem was studied both experimentally and numerically. A small valve was tested in the authors’ experiment facility first to provide validation data. For this valve, numerical predictions of mass flow rate agree with experimental data. Then, simulations were scaled up to valves in a real power-cycle design. The traditional gas-service valve model fails to predict mass flow rate at low-pressure ratios. A modification was proposed to improve the current gas-service valve model by changing the choked-flow check.
Recent Advances and New Trends in Flip Chip Technology
Authors: Lau John H.
Published: July 2016

Recent advances in flip chip technology such as wafer bumping, package substrate, flip chip assembly, and underfill will be presented in this study. Emphasis is placed on the latest developments of these areas in the past few years. Their future trends will also be recommended.
Flow Field Characterization at the Outlet of a Lean Burn Single-Sector Combustor by Laser-Optical Methods
Authors: Schroll Michael , Doll Ulrich , Stockhausen Guido , Meier Ulrich , Willert Chris , Hassa Christoph , Bagchi Imon
Published: July 2016

High overall pressure ratio (OPR) engine cycles for reduced NOx emissions will generate new aggravated requirements and boundary conditions by implementing low emission combustion technologies into advanced engine architectures. Lean burn combustion systems will have a significant impact on the temperature and velocity traverse at the combustor exit. Lean burn fuel injectors dominate the combustor exit conditions. This is due to the fact that they pass a majority of the total combustor flow, and to the lack of mixing jets like in a conventional combustor. With the transition to high-pressure engines, it is essential to fully understand and determine the high energetic interface between combustor and turbine to avoid excessive cooling. Velocity distributions and their fluctuations at the combustor exit for lean burn are of special interest as they can influence the efficiency and capacity of the turbine. A lean burn single-sector combustor was designed and built at DLR, providing optical access to its rectangular exit section. The sector was operated with a fuel-staged lean burn injector. Measurements were performed under idle and cruise operating conditions. Two velocity measurement techniques were used in the demanding environment of highly luminous flames under elevated pressures: particle image velocimetry (PIV) and filtered Rayleigh scattering (FRS). The latter was used for the first time in an aero-engine combustor environment. In addition to a conventional signal detection arrangement, FRS was also applied with an endoscope for signal collection, to assess its practicality for a potential future application in a full annular combustor with restricted optical access.
A Coupled Shear Stress-Diffusion Model for Adhesively Bonded Single Lap Joints
Authors: Nassar Sayed A. , Mazhari Emad
Published: July 2016

In this study, a coupled shear stress-diffusion model is developed for the analysis of adhesively bonded single lap joints (SLJs) by applying Fickian diffusion model to the adhesive layer. Differential equations of equilibrium are formulated in terms of adhesive material properties that are time and location dependent. By invoking a Volkersen approach on the equilibrium equations, a shear stress differential equation is formulated and numerically solved. Several scenarios are considered for investigating the effect of diffusion on shear stress distribution in adhesively bonded SLJs. Detailed discussion of the results is presented.
A Method for Solving Large-Scale Multiloop Constrained Dynamical Systems Using Structural Decomposition
Authors: Xiong Tao , Ding Jianwan , Wu Yizhong , Chen Liping , Hou Wenjie
Published: July 2016

A structural decomposition method based on symbol operation for solving differential algebraic equations (DAEs) is developed. Constrained dynamical systems are represented in terms of DAEs. State-space methods are universal for solving DAEs in general forms, but for complex systems with multiple degrees-of-freedom, these methods will become difficult and time consuming because they involve detecting Jacobian singularities and reselecting the state variables. Therefore, we adopted a strategy of dividing and conquering. A large-scale system with multiple degrees-of-freedom can be divided into several subsystems based on the topology. Next, the problem of selecting all of the state variables from the whole system can be transformed into selecting one or several from each subsystem successively. At the same time, Jacobian singularities can also be easily detected in each subsystem. To decompose the original dynamical system completely, as the algebraic constraint equations are underdetermined, we proposed a principle of minimum variable reference degree to achieve the bipartite matching. Subsequently, the subsystems are determined by aggregating the strongly connected components in the algebraic constraint equations. After that determination, the free variables remain; therefore, a merging algorithm is proposed to allocate these variables into each subsystem optimally. Several examples are given to show that the proposed method is not only easy to implement but also efficient.
Clinical Facts Along With a Feedback Control Perspective Suggest That Increased Response Time Might Be the Cause of Parkinsonian Rest Tremor
Authors: Shah Vrutangkumar V. , Goyal Sachin , Palanthandalam-Madapusi Harish J.
Published: July 2016

Parkinson's disease (PD) is a neurodegenerative disorder characterized by increased response times leading to a variety of biomechanical symptoms, such as tremors, stooping, and gait instability. Although the deterioration in biomechanical control can intuitively be related to sluggish response times, how the delay leads to such biomechanical symptoms as tremor is not yet understood. Only recently has it been explained from the perspective of feedback control theory that delay beyond a threshold can be the cause of Parkinsonian tremor (Palanthandalam-Madapusi and Goyal, 2011, “Is Parkinsonian Tremor a Limit Cycle?” J. Mech. Med. Biol., 11(5), pp. 1017–1023). The present paper correlates several observations from this perspective to clinical facts and reinforces them with simple numerical and experimental examples. Thus, the present work provides a framework toward developing a deeper conceptual understanding of the mechanism behind PD symptoms. Furthermore, it lays a foundation for developing tools for diagnosis and progress tracking of the disease by identifying some key trends.
Convective Heat Transfer From a Heated Plate to the Orthogonally Impinging Air Jet
Authors: Bhagwat Abhishek B. , Sridharan Arunkumar
Published: July 2016

The convective heat transfer process between the orthogonal air jet impingement on a uniformly heated flat plate is studied numerically. In this numerical study, three-dimensional (3D) simulations are carried out in Fluent 14.0 to investigate the effect of Reynolds number, distance between nozzle exit and the plate on the heat transfer characteristics. V2F turbulence model has been used to model turbulence. Standard κ–ε, Realizable κ–ε, κ–ε RNG, SST κ–ω, Standard κ–ω, V2F turbulence models have been studied for orthogonal jet impingement in this work. It is observed that for jet exit to plate distance (Z/d) of 0.5 ≤ Z/d ≤ 6, V2F model is best suited. For Z/d ≤ 0.5 and Z/d ≥ 6, numerical results vary significantly from the experimental results. Reynolds number of 12,000, 20,000, and 28,000 has been studied. In this paper, results for various jet exit to the plate distance (Z/d) from 0.5 to 10 are presented. At low jet plate spacing Z/d < 4, secondary peak in Nusselt number distribution over the plate is visible in experimental results. V2F model correctly predicts the secondary peak in Nusselt number variation over the plate. Other models fail to predict the secondary peak which is of significant importance in air jet impingement at low jet-plate spacing (Z/d < 4).
Nonlinear Analysis of Chaotic Flow in a Three-Dimensional Closed-Loop Pulsating Heat Pipe
Authors: Pouryoussefi S. M. , Zhang Yuwen
Published: July 2016

Numerical simulation has been conducted for the chaotic flow in a 3D closed-loop pulsating heat pipe (PHP). Heat flux and constant temperature boundary conditions were applied for evaporator and condenser sections, respectively. Water and ethanol were used as working fluids. Volume of fluid (VOF) method has been employed for two-phase flow simulation. Spectral analysis of temperature time series was carried out using power spectrum density (PSD) method. Existence of dominant peak in PSD diagram indicated periodic or quasi-periodic behavior in temperature oscillations at particular frequencies. Correlation dimension values for ethanol as working fluid were found to be higher than that for water under the same operating conditions. Similar range of Lyapunov exponent values for the PHP with water and ethanol as working fluids indicated strong dependency of Lyapunov exponent on the structure and dimensions of the PHP. An O-ring structure pattern was obtained for reconstructed 3D attractor at periodic or quasi-periodic behavior of temperature oscillations. Minimum thermal resistance of 0.85 °C/W and 0.88 °C/W were obtained for PHP with water and ethanol, respectively. Simulation results showed good agreement with the experimental results from other work under the same operating conditions.
Solar Variability Datalogger
Authors: Lave Matthew , Stein Joshua , Smith Ryan
Published: July 2016

To address the lack of knowledge of local solar variability, we have developed and deployed a low-cost solar variability datalogger (SVD). While most currently used solar irradiance sensors are expensive pyranometers with high accuracy (relevant for annual energy estimates), low-cost sensors display similar precision (relevant for solar variability) as high-cost pyranometers, even if they are not as accurate. In this work, we present evaluation of various low-cost irradiance sensor types, describe the SVD, and present validation and comparison of the SVD collected data. The low cost and ease of use of the SVD will enable a greater understanding of local solar variability, which will reduce developer and utility uncertainty about the impact of solar photovoltaic (PV) installations and thus will encourage greater penetrations of solar energy.
Spatial atomic layer deposition of ZnO/TiO2 nanolaminates
Authors: Chen Rong , Lin Ji-Long , He Wen-Jie , Duan Chen-Long , Peng Qi , Wang Xiao-Lei , Shan Bin
Published: July 2016

Spatial atomic layer deposition (S-ALD) is a potential high-throughput manufacturing technique offering fast and large scale ultrathin films deposition. Here, an S-ALD system with modular injectors is introduced for fabricating binary oxides and their nanolaminates. By optimizing the deposition conditions, both ZnO and TiO2 films demonstrate linear growth and desired surface morphology. The as-deposited ZnO film has high carrier mobility, and the TiO2 film shows suitable optical transmittance and band gap. The ZnO/TiO2 nanolaminates are fabricated by alternating substrate movement between each S-ALD modular units of ZnO and TiO2. The grazing incidence x-ray diffraction spectra of nanolaminates demonstrating the signature peaks are weaker for the same thickness nanolaminates with more bilayers, suggesting tuning nanolaminates from crystalline to amorphous. Optical transmittances of ZnO/TiO2 laminates are enhanced with the increase of the bilayers' number in the visible range. Refractive indices of nanolaminates increase with the thickness of each bilayer decreasing, which demonstrates the feasibility of obtaining desired refractive indices by controlling the bilayer number. The electronic properties, including mobility, carrier concentration, and conductivity, are also tunable with different bilayers.
SU‐B‐BRA‐03: A Physician Perspective on the Value of Medical Physics
Authors: Burri S.
Published: July 2016

In the current rapidly changing Healthcare environment, many groups are competing for limited resources. How can medical physicists position themselves to be a relevant stakeholder in the discussion of how those resources are allocated Our value goes beyond what can be shown in a business plan and is heavily involved with safety and quality.

Three areas will be explored:

What is our value?

Who needs to receive that message?

How do we communicate that message?

To help frame the discussion in terms of how other stakeholders may view the value of medical physicists, a physician and an administrator will present their perspective.

Lastly, a multidisciplinary panel will present real life examples of strategies that can be utilized today to establish the value of medical physicists. The presentation of these examples will lead into an interactive question and answer time.

V. Willcut, I work for Elekta. There was no research associated with this talk.
SU‐B‐BRA‐06: Panel Member
Authors: Clements J.
Published: July 2016

In the current rapidly changing Healthcare environment, many groups are competing for limited resources. How can medical physicists position themselves to be a relevant stakeholder in the discussion of how those resources are allocated Our value goes beyond what can be shown in a business plan and is heavily involved with safety and quality.

Three areas will be explored:

What is our value?

Who needs to receive that message?

How do we communicate that message?

To help frame the discussion in terms of how other stakeholders may view the value of medical physicists, a physician and an administrator will present their perspective.

Lastly, a multidisciplinary panel will present real life examples of strategies that can be utilized today to establish the value of medical physicists. The presentation of these examples will lead into an interactive question and answer time.

V. Willcut, I work for Elekta. There was no research associated with this talk.
SU‐C‐201‐02: Dosimetric Verification of SBRT with FFF‐VMAT Using a 3‐D Radiochromic/Optical‐CT Dosimetry System
Authors: Na Y , Black P , Adamovics J , Wuu C
Published: July 2016

Purpose:

With an increasing use of small field size and high dose rate irradiation in the advances of radiotherapy techniques, such as stereotactic body radiotherapy (SBRT) and stereotactic radiosurgery (SRS), an in‐depth quality assurance (QA) system is required. The purpose of this study is to investigate a high resolution optical CT‐based 3D radiochromic dosimetry system for SBRT with intensity modulated radiotherapy (IMRT) and flattening filter free (FFF) volumetric modulated arc therapy (VMAT).

Methods:

Cylindrical PRESAGE radiochromic dosimeters of 10cm height and 11cm diameter were used to validate SBRT. Four external landmarks were placed on the surface of each dosimeter to define the isocenter of target. SBRT plans were delivered using a Varian TrueBeam™ linear accelerator (LINAC). Three validation plans, SBRT with IMRT (6MV 600MU/min), FFF‐VMAT (10MV 2400MU/min), and mixed FFF‐VMAT (6MV 1400MU/min, 10MV 2400MU/min), were delivered to the PRESAGE dosimeters. Each irradiated PRESAGE dosimeter was scanned using a single laser beam optical CT scanner and reconstructed with a 1mm × 1mm high spatial resolution. The comparison of measured dose distributions of irradiated PRESAGE dosimeters to those calculated by Pinnacle3 treatment planning system (TPS) were performed with a 10% dose threshold, 3% dose difference (DD), and 3mm distance‐to‐agreement (DTA) Gamma criteria.

Results:

The average pass rates for the gamma comparisons between PRESAGE and Pinnacle3 in the transverse, sagittal, coronal planes were 94.6%, 95.9%, and 96.4% for SBRT with IMRT, FFF‐VMAT, and mixed FFF‐VMAT plans, respectively. A good agreement of the isodose distributions of those comparisons were shown at the isodose lines 50%, 70%, 80%, 90% and 98%.

Conclusion:

This study demonstrates the feasibility of the high resolution optical CT‐based 3D radiochromic dosimetry system for validation of SBRT with IMRT and FFF‐VMAT. This dosimetry system offers higher precision QA with 3D dose information for small beams compared to what is currently available.
SU‐C‐201‐06: Small Field Correction Factors for the MicroDiamond Detector in the Gamma Knife‐Model C Derived Using Monte Carlo Methods
Authors: Barrett J C , Knill C
Published: July 2016

Purpose:

To determine small field correction factors for PTW's microDiamond detector in Elekta's Gamma Knife Model‐C unit. These factors allow the microDiamond to be used in QA measurements of output factors in the Gamma Knife Model‐C; additionally, the results also contribute to the discussion on the water equivalence of the relatively‐new microDiamond detector and its overall effectiveness in small field applications.

Methods:

The small field correction factors were calculated as k correction factors according to the Alfonso formalism. An MC model of the Gamma Knife and microDiamond was built with the EGSnrc code system, using BEAMnrc and DOSRZnrc user codes. Validation of the model was accomplished by simulating field output factors and measurement ratios for an available ABS plastic phantom and then comparing simulated results to film measurements, detector measurements, and treatment planning system (TPS) data. Once validated, the final k factors were determined by applying the model to a more waterlike solid water phantom.

Results:

During validation, all MC methods agreed with experiment within the stated uncertainties: MC determined field output factors agreed within 0.6% of the TPS and 1.4% of film; and MC simulated measurement ratios matched physically measured ratios within 1%. The final k correction factors for the PTW microDiamond in the solid water phantom approached unity to within 0.4%±1.7% for all the helmet sizes except the 4 mm; the 4 mm helmet size over‐responded by 3.2%±1.7%, resulting in a k factor of 0.969.

Conclusion:

Similar to what has been found in the Gamma Knife Perfexion, the PTW microDiamond requires little to no corrections except for the smallest 4 mm field. The over‐response can be corrected via the Alfonso formalism using the correction factors determined in this work. Using the MC calculated correction factors, the PTW microDiamond detector is an effective dosimeter in all available helmet sizes.

The authors would like to thank PTW (Friedberg, Germany) for providing the PTW microDiamond detector for this research.
SU‐C‐BRC‐06: OpenCL‐Based Cross‐Platform Monte Carlo Simulation Package for Carbon Ion Therapy
Authors: Qin N , Pinto M , Tian Z , Dedes G , Pompos A , Jiang S , Parodi K , Jia X
Published: July 2016

Purpose:

Monte Carlo (MC) simulation is considered to be the most accurate method for calculation of absorbed dose and fundamental physical quantities related to biological effects in carbon ion therapy. Its long computation time impedes clinical and research applications. We have developed an MC package, goCMC, on parallel processing platforms, aiming at achieving accurate and efficient simulations for carbon therapy.

Methods:

goCMC was developed under OpenCL framework. It supported transport simulation in voxelized geometry with kinetic energy up to 450 MeV/u. Class II condensed history algorithm was employed for charged particle transport with stopping power computed via Bethe‐Bloch equation. Secondary electrons were not transported with their energy locally deposited. Energy straggling and multiple scattering were modeled. Production of secondary charged particles from nuclear interactions was implemented based on cross section and yield data from Geant4. They were transported via the condensed history scheme. goCMC supported scoring various quantities of interest e.g. physical dose, particle fluence, spectrum, linear energy transfer, and positron emitting nuclei.

Results:

goCMC has been benchmarked against Geant4 with different phantoms and beam energies. For 100 MeV/u, 250 MeV/u and 400 MeV/u beams impinging to a water phantom, range difference was 0.03 mm, 0.20 mm and 0.53 mm, and mean dose difference was 0.47%, 0.72% and 0.79%, respectively. goCMC can run on various computing devices. Depending on the beam energy and voxel size, it took 20∼100 seconds to simulate 107 carbons on an AMD Radeon GPU card. The corresponding CPU time for Geant4 with the same setup was 60∼100 hours.

Conclusion:

We have developed an OpenCL‐based cross‐platform carbon MC simulation package, goCMC. Its accuracy, efficiency and portability make goCMC attractive for research and clinical applications in carbon therapy.
SU‐C‐BRB‐03: Cross‐Institutional Validation of An Ultrafast Automatic Planning Platform for Breast Irradiation
Authors: Li T , Sheng Y , Lockamy V , Anne P , Simone N , Wu QJ , Yu Y
Published: July 2016

Purpose:

Recently an ultrafast automatic planning system for breast irradiation using tangential beams was developed by modeling relationships between patient anatomy and achieved dose distribution. This study evaluates the performance of this system when applied to a different patient population and dose calculation algorithm.

Methods:

The system and its anatomy‐to‐dose models was developed at institution A based on 20 cases, which were planned using manual fluence painting technique and calculated WITH heterogeneity correction. Institution B uses field‐in‐field planning technique and dose calculation WITHOUT heterogeneity correction. 11 breast cases treated at Institution B were randomly selected for retrospective study, including left and right sides, and different breast size (irradiated volumes defined by Jaw/MLC opening range from 875cc to 3516cc). Comparisons between plans generated automatically (Auto‐Plans) and those used for treatment (Clinical‐Plans) included: energy choice (single/mixed), volumes receiving 95%/100%/105%/110% Rx dose (V95%/V100%/V105%/V100%) relative to irradiated volume, D1cc, and LungV20Gy.

Results:

In 9 out of 11 cases single/mixed energy choice made by the software agreed with Clinical‐Plans. For the remaining 2 cases software recommended using mixed energy and dosimetric improvements were observed. V100% were similar (p=0.223, Wilcoxon Signed‐Rank test) between Auto‐Plans and Clinical‐Plans (57.6±8.9% vs. 54.8±9.5%). V95% is 2.3±3.0% higher for Auto‐Plans (p=0.027), indicating reduced cold areas. Hot spot volume V105% were significantly reduced in Auto‐Plan by 14.4±7.2% (p=0.004). Absolute V105% was reduced from 395.6±359.9cc for Clinical‐Plans to 108.7±163cc for Auto‐Plans. D1cc was 107.4±2.8% for Auto‐Plans, and 109.2±2.4% for Clinical‐Plans (p=0.056). LungV20Gy were 13.6±4.0% for Auto‐Plan vs. 14.0±4.1% for Clinical‐Plans (p=0.043). All optimizations were finished within 1.5min.

Conclusion:

The performance of this breast auto‐planning system remained stable and satisfactory when applied to a different patient population and dose calculation algorithm. The auto‐planning system was able to produce clinically similar Rx dose coverage with significantly improved homogeneity inside breast tissue, in less than 1.5min.
SU‐C‐BRA‐03: An Automated and Quick Contour Errordetection for Auto Segmentation in Online Adaptive Radiotherapy
Authors: Zhang J , Ates O , Li X
Published: July 2016

Purpose:

To develop a tool that can quickly and automatically assess contour quality generated from auto segmentation during online adaptive replanning.

Methods:

Due to the strict time requirement of online replanning and lack of ‘ground truth’ contours in daily images, our method starts with assessing image registration accuracy focusing on the surface of the organ in question. Several metrics tightly related to registration accuracy including Jacobian maps, contours shell deformation, and voxel‐based root mean square (RMS) analysis were computed. To identify correct contours, additional metrics and an adaptive decision tree are introduced. To approve in principle, tests were performed with CT sets, planned and daily CTs acquired using a CT‐on‐rails during routine CT‐guided RT delivery for 20 prostate cancer patients. The contours generated on daily CTs using an auto‐segmentation tool (ADMIRE, Elekta, MIM) based on deformable image registration of the planning CT and daily CT were tested.

Results:

The deformed contours of 20 patients with total of 60 structures were manually checked as baselines. The incorrect rate of total contours is 49%. To evaluate the quality of local deformation, the Jacobian determinant (1.047±0.045) on contours has been analyzed. In an analysis of rectum contour shell deformed, the higher rate (0.41) of error contours detection was obtained compared to 0.32 with manual check. All automated detections took less than 5 seconds.

Conclusion:

The proposed method can effectively detect contour errors in micro and macro scope by evaluating multiple deformable registration metrics in a parallel computing process. Future work will focus on improving practicability and optimizing calculation algorithms and metric selection.
SU‐C‐BRA‐04: Automated Segmentation of Head‐And‐Neck CT Images for Radiotherapy Treatment Planning Via Multi‐Atlas Machine Learning (MAML)
Authors: Ren X , Sharp G , Gao H
Published: July 2016

Purpose:

Accurate image segmentation is a crucial step during image guided radiation therapy. This work proposes multi‐atlas machine learning (MAML) algorithm for automated segmentation of head‐and‐neck CT images.

Methods:

As the first step, the algorithm utilizes normalized mutual information as similarity metric, affine registration combined with multiresolution B‐Spline registration, and then fuses together using the label fusion strategy via Plastimatch. As the second step, the following feature selection strategy is proposed to extract five feature components from reference or atlas images: intensity (I), distance map (D), box (B), center of gravity (C) and stable point (S). The box feature B is novel. It describes a relative position from each point to minimum inscribed rectangle of ROI. The center‐of‐gravity feature C is the 3D Euclidean distance from a sample point to the ROI center of gravity, and then S is the distance of the sample point to the landmarks. Then, we adopt random forest (RF) in Scikit‐learn, a Python module integrating a wide range of state‐of‐the‐art machine learning algorithms as classifier. Different feature and atlas strategies are used for different ROIs for improved performance, such as multi‐atlas strategy with reference box for brainstem, and single‐atlas strategy with reference landmark for optic chiasm.

Results:

The algorithm was validated on a set of 33 CT images with manual contours using a leave‐one‐out cross‐validation strategy. Dice similarity coefficients between manual contours and automated contours were calculated: the proposed MAML method had an improvement from 0.79 to 0.83 for brainstem and 0.11 to 0.52 for optic chiasm with respect to multi‐atlas segmentation method (MA).

Conclusion:

A MAML method has been proposed for automated segmentation of head‐and‐neck CT images with improved performance. It provides the comparable result in brainstem and the improved result in optic chiasm compared with MA.

Xuhua Ren and Hao Gao were partially supported by the NSFC (#11405105), the 973 Program (#2015CB856000), and the Shanghai Pujiang Talent Program (#14PJ1404500).
SU‐C‐202‐01: Incorporating Time‐Dependent Hypoxia in IMRT Planning
Authors: Roy A , Nohadani O
Published: July 2016

Purpose:

To incorporate uncertainties in oxygenation of tumor cells into radiation therapy planning via robust optimization. The model is demonstrated using a clinical prostate cancer case.

Methods:

The tumor oxygenation levels are determined based on pre‐ and mid‐treatment PET scans. To account for oxygenation changes, we use a radio‐sensitivity factor for the effective dose necessary to treat hypoxic cells. Due to the unpredictable nature of re‐oxygenation of hypoxic cells, the radio‐sensitivity factor and its change is modeled to reside in a time‐dependent uncertainty set. This uncertainty can adapt to both pre‐ and mid‐treatment scans, resulting in a two‐stage robust treatment planning model. We develop a robust counterpart reformulation that transforms the original NP‐hard problem into a linear program consisting of finitely many linear constraints, which can be solved efficiently.

Results:

The robust plan is compared to both the corresponding fractionated plan which ignores hypoxia, and to the commonly practiced dose‐escalated plan that uniformly increases dose based on initial oxygen concentrations. For PTV, the robust plan improves D50, D95, and EUD by 4% on average compared to fractionated, and by 11% compared to the optimal escalated plan. Moreover, the robust plan spared organs at risk similar to the fractionated plan, while the escalated plan led to over 170% increase of Bladder D30.

Conclusion:

The proposed robust adaptive model can improve tumor coverage by increasing dose to hypoxic tumor voxels that is overlooked by common fractionated treatments. In addition, the robust model anticipates the re‐oxygenation process, thus reducing the excess dose at later fractions in comparison to uniform dose‐escalation methods.
SU‐C‐209‐03: Anti‐Scatter Grid‐Line Artifact Minimization for Removing the Grid Lines for Three Different Grids Used with a High Resolution CMOS Detector
Authors: Rana R , Bednarek D , Rudin S
Published: July 2016

Purpose:

Demonstrate the effectiveness of an anti‐scatter grid artifact minimization method by removing the grid‐line artifacts for three different grids when used with a high resolution CMOS detector.

Method:

Three different stationary x‐ray grids were used with a high resolution CMOS x‐ray detector (Dexela 1207, 75 µm pixels, sensitivity area 11.5cm × 6.5cm) to image a simulated artery block phantom (Nuclear Associates, Stenosis/Aneurysm Artery Block 76–705) combined with a frontal head phantom used as the scattering source. The x‐ray parameters were 98kVp, 200mA, and 16ms for all grids. With all the three grids, two images were acquired: the first for a scatter‐less flat field including the grid and the second of the object with the grid which may still have some scatter transmission. Because scatter has a low spatial frequency distribution, it was represented by an estimated constant value as an initial approximation and subtracted from the image of the object with grid before dividing by an average frame of the grid flat‐field with no scatter. The constant value was iteratively changed to minimize residual grid‐line artifact. This artifact minimization process was used for all the three grids.

Results:

Anti‐scatter grid lines artifacts were successfully eliminated in all the three final images taken with the three different grids. The image contrast and CNR were also compared before and after the correction, and also compared with those from the image of the object when no grid was used. The corrected images showed an increase in CNR of approximately 28%, 33% and 25% for the three grids, as compared to the images when no grid at all was used.

Conclusion:

Anti‐scatter grid‐artifact minimization works effectively irrespective of the specifications of the grid when it is used with a high spatial resolution detector.

Partial support from NIH Grant R01‐EB002873 and Toshiba Medical Systems Corp.