bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Maverick in the Field: The Oram Group and Fundraising in the Black College Community during the 1970s
Authors: Gasman Marybeth , Drezner Noah D. 
Published: October 2009

The Oram firm was really a different animal. We cherished a strong anticorporate corporate culture, we were cause-driven, and we served liberal and left-wing counter-cultural organizations.Since its founding in 1939, the Oram Group has been a maverick in the field of fundraising, lending its expertise to the areas of education, welfare, social action, civil rights, the arts, and the environment. Beginning with the organization's founder, Harold Oram, continuing to the current president and chief executive officer Henry Goldstein, Oram staff members have had an interest in supporting progressive (i.e., social justice-oriented) causes. Influenced by Franklin D. Roosevelt's New Deal policies and Lyndon B. Johnson's vision of a Great Society, the Oram Group staff has been steadfast in its dedication, with founder Harold Oram referring to the organization's work as “saving the world.” This approach was different from that of earlier fundraising organizations, such as Marts and Lundy or John Price Jones—firms that worked, by and large, with elite white institutions and with black colleges under the direction of white philanthropists. For example, according to Robert L . Payton, for Arnaud C. Marts [and his colleagues at Marts and Lundy],Philanthropy [was] closely linked to the free market economy, local government, and individual responsibility. The emerging civil rights movement, the decay of the inner cities, environmental pollution, and the radical challenges to authority were not yet part of Mart's [sic] consciousness nor of the general public's. Freedom and patriotism were the dominant slogans rather than equality and justice.
A high spatial resolution in vivo 1H magnetic resonance spectroscopic imaging technique for the human breast at
Authors: Hu Jiani , Feng Wenzheng , Hua Jia , Jiang Quan , Xuan Yang , Li Tao , Haacke E. Mark 
Published: October 2009

Purpose:The technical challenges that have prevented routine proton magnetic resonance spectroscopic imaging (1H MRSI) examinations of the breast include insufficient spatial resolution, increased difficulties in shimming compared to the brain, and strong lipid contamination at short echo time (TE) at. The authors investigated the feasibility of high spatial resolution 1H MRSI of human breast cancer in a clinical setting at .Methods:Ten patient studies (eight cancers and two benign lesions) were performed in a whole‐body clinical imager using a pulse sequence consisting of optional outer volume presaturation, optional CHESS pulse for lipid suppression, CHESS pulse for water suppression, and standard 2D/3D PRESS pulse sequence with an elliptical weighted ‐space sampling scheme.Results:All ten studies were technically successful. The spectral quality was acceptable for all cases even the one with a width of water peak at half height. Choline (Cho) signals were clearly visible in malignant lesion areas, while there was no detectable Cho in normal appearing breast or in benign lesions. It was also observed that the distribution of Cho signal can be nonuniform across MRI demonstrated lesions.Conclusions:To the author's knowledge, this is the first 2D/3D MRSI study of human breast cancer with short TE (less than) at and the highest spatial resolution (up to ) to date. In conclusion, the authors have presented a robust technique for high spatial resolution in vivo 1H MRSI of human breast cancer that uses the combined advantages of high field, short TE, multivoxel, and high spatial resolution itself to overcome the major technical challenges and illustrated its potential for routine clinical examination as well as advantages over single‐voxel techniques in studying metabolite heterogeneity.
Development and testing of texture discriminators for the analysis of trabecular bone in proximal femur radiographs
Authors: Huber M. B. , Carballido‐Gamio J. , Fritscher K. , Schubert R. , Haenni M. , Hengg C. , Majumdar S. , Link T. M. 
Published: October 2009

Purpose:Texture analysis of femur radiographs may serve as a potential low cost technique to predict osteoporotic fracture risk and has received considerable attention in the past years. A further application of this technique may be the measurement of the quality of specific bone compartments to provide useful information for treatment of bone fractures. Two challenges of texture analysis are the selection of the best suitable texture measure and reproducible placement of regions of interest (ROIs). The goal of this in vitro study was to automatically place ROIs in radiographs of proximal femur specimens and to calculate correlations between various different texture analysis methods and the femurs’ anchorage strength.Methods:Radiographs were obtained from 14 femoral specimens and bone mineral density (BMD) was measured in the femoral neck. Biomechanical testing was performed to assess the anchorage strength in terms of failure load, breakaway torque, and number of cycles. Images were segmented using a framework that is based on the usage of level sets and statistical in‐shape models. Five ROIs were automatically placed in the head, upper and lower neck, trochanteric, and shaft compartment in an atlas subject. All other subjects were registered rigidly, affinely, and nonlinearly, and the resulting transformation was used to map the five ROIs onto the individual femora.Results:In each ROI, texture features were extracted using gray level co‐occurence matrices (GLCM), third‐order GLCM, morphological gradients (MGs), Minkowski dimensions (MDs), Minkowski functionals (MFs), Gaussian Markov random fields, and scaling index method (SIM). Coefficients of determination for each texture feature with parameters of anchorage strength were computed. In a stepwise multiregression analysis, the most predictive parameters were identified in different models. Texture features were highly correlated with anchorage strength estimated by the failure load of up to (MF and MG features, ) and were partially independent of BMD. The correlations were dependent on the choice of the ROI and the texture measure. The best predictive multiregression model for failure load included a set of recently developed texture methods (MF and SIM) but excluded bone mineral density and commonly used texture measures.Conclusions:The results suggest that texture information contained in trabecular bone structure visualized on radiographs may predict whether an implant anchorage can be used and may determine the local bone quality from preoperative radiographs.
Quantitative blood flow measurements in the small animal cardiopulmonary system using digital subtraction angiography
Authors: Lin MingDe , Marshall Craig T. , Qi Yi , Johnston Samuel M. , Badea Cristian T. , Piantadosi Claude A. , Johnson G. Allan 
Published: October 2009

Purpose:The use of preclinical rodent models of disease continues to grow because these models help elucidate pathogenic mechanisms and provide robust test beds for drug development. Among the major anatomic and physiologic indicators of disease progression and genetic or drug modification of responses are measurements of blood vessel caliber and flow. Moreover, cardiopulmonary blood flow is a critical indicator of gas exchange. Current methods of measuring cardiopulmonary blood flow suffer from some or all of the following limitations—they produce relative values, are limited to global measurements, do not provide vasculature visualization, are not able to measure acute changes, are invasive, or require euthanasia.Methods:In this study, high‐spatial and high‐temporal resolution x‐ray digital subtraction angiography (DSA) was used to obtain vasculature visualization, quantitative blood flow in absolute metrics (ml/min instead of arbitrary units or velocity), and relative blood volume dynamics from discrete regions of interest on a pixel‐by‐pixel basis .Results:A series of calibrations linked the DSA flow measurements to standard physiological measurement using thermodilution and Fick's method for cardiac output (CO), which in eight anesthetized Fischer‐344 rats was found to be. Phantom experiments were conducted to calibrate the radiographic density to vessel thickness, allowing a link of DSA cardiac output measurements to cardiopulmonary blood flow measurements in discrete regions of interest. The scaling factor linking relative DSA cardiac output measurements to the Fick's absolute measurements was found to be .Conclusions:This calibrated DSA approach allows repeated simultaneous visualization of vasculature and measurement of blood flow dynamics on a regional level in the living rat.
Accelerating Monte Carlo simulations of photon transport in a voxelized geometry using a massively parallel graphics processing unit
Authors: Badal Andreu , Badano Aldo 
Published: October 2009

Purpose:It is a known fact that Monte Carlo simulations of radiation transport are computationally intensive and may require long computing times. The authors introduce a new paradigm for the acceleration of Monte Carlo simulations: The use of a graphics processing unit (GPU) as the main computing device instead of a central processing unit (CPU).Methods:A GPU‐based Monte Carlo code that simulates photon transport in a voxelized geometry with the accurate physics models from PENELOPE has been developed using the CUDA™ programming model (NVIDIA Corporation, Santa Clara, CA).Results:An outline of the new code and a sample x‐ray imaging simulation with an anthropomorphic phantom are presented. A remarkable 27‐fold speed up factor was obtained using a GPU compared to a single core CPU.Conclusions:The reported results show that GPUs are currently a good alternative to CPUs for the simulation of radiation transport. Since the performance of GPUs is currently increasing at a faster pace than that of CPUs, the advantages of GPU‐based software are likely to be more pronounced in the future.
GAFCHROMIC® EBT photospectral dose response dependence on temperature and implications for flat bed scanning
Authors: Buchauer Konrad , Hillbrand Elmar , de Vries Alexander 
Published: October 2009

Purpose:Various forms of GAFCHROMIC® film have been used for several years as radiographic media for measuring dose distributions. GAFCHROMIC® EBT (GC‐EBT) film is particularly useful for clinical dose ranges. This thin film dosimeter develops a blue color ( approximately 635 nm) when irradiated with ionizing radiation.Methods:Temperature controlled photospectrometry was used to assess temperature related readout changes in GC‐EBT type film dosimetry. For observing clinical impact of findings, multiple scan studies with rising flat bed scanner temperature were performed.Results:The whole optical spectrum in the observed wavelength range of 450–700 nm shows a distinct spectrum shift linear with temperature toward lower wavelengths when readout temperature is increased. In addition, absorption decreases in maximum regions and increases in minimum regions of the absorbance spectrum. The most pronounced wavelength dependent readout differences occur in the slopes of the spectrum curves. Absorption readout differences of −1%/°C for a 2.7 Gy irradiated film piece at a readout wavelength of approximately 650 nm can be found. The readout difference is strongly dependent on readout light spectral characteristic, irradiation dose, and temperature. Readout difference can be positive or negative. Characteristic temperature behavior patterns are present for each color channel of a flat bed scanner. All described effects are reversible within the measurement accuracy of this study.Conclusions:When using unsuitable readout light, careful control of the readout temperature is necessary in order to obtain consistent and accurate results. Adapted GC‐EBT type film dosimetry guidelines are presented. Temperature dependent readout differences on a flat bed scanner can be avoided when using scanner bed temperature as a fixed dosimetry parameter.
Discrete beta dose kernel matrices for nuclides applied in targeted radionuclide therapy (TRT) calculated with MCNP5
Authors: Reiner Dora , Blaickner Matthias , Rattay Frank 
Published: October 2009

Purpose:Radiopharmaceuticals administered in targeted radionuclide therapy (TRT) rely to a great extent not only on beta‐emitting nuclides but also on emitters of monoenergetic electrons. Recent advances like combined PET/CT devices, the consequential coregistration of both data, the concept of using beta couples for diagnosis and therapy, respectively, as well as the development of voxel models offer a great potential for developing TRT dose calculation systems similar to those available for external beam treatment planning. The deterministic algorithms in question for this task are based on the convolution of three‐dimensional matrices, one representing the activity distribution and the other the dose point kernel. This study aims to report on three‐dimensional kernel matrices for various nuclides used in TRT.Methods:The Monte Carlo code MCNP5 was used to calculate discrete dose kernels of beta particles including the contributions from their respective secondary radiation in soft tissue for the following nuclides: , , , , , , , , , and . For each nuclide a kernel cube of was calculated, the dimensions of a voxel being . Additional kernels with voxel sizes of were simulated.Results:Comparison with the‐value data regarding , , , and of the MIRD committee which were calculated with the EGS4 code showed a very good agreement, the secondary particle transport of being the only exception. Documented analytical kernels on the other side show deviations very close and very far to the source.Conclusions:The good accordance with the only discrete dose kernels published up to date justifies the method chosen. Together with the additional six nuclides, this report provides a considerable database for three‐dimensional kernel matrices with regard to beta radionuclides applied in TRT. In contrast to analytical dose point kernels, the discrete kernels elude the problem of overestimation near the source and take energy depositions into account, which occur beyond the range of the continuous‐slowing‐down approximation (csda range). Recalculation of the kernels to other dose kernels with varying voxel dimensions, cubic or noncubic, is shown to be easily manageable and thereby provides a resolution‐independent system of dose calculation.
X‐ray energy optimization in minibeam radiation therapy
Authors: Prezado Y. , Thengumpallil S. , Renier M. , Bravin A. 
Published: October 2009

Purpose:The purpose of this work is to assess which energy in minibeam radiation therapy provides the best compromise between the deposited dose in the tumor and the sparing of the healthy tissues.Methods:Monte Carlo simulations (PENELOPE 2006) have been used as a method to calculate the ratio of the peak‐to‐valley doses (PVDR) in the healthy tissues and in the tumor for different beam energies. The maximization of the ratio of PVDR in the healthy tissues and in the tumor has been used as a criterion.Results:The main result of this work is that, for the parameters being used in preclinical trials (minibeam sizes of and center‐to‐center separation), the optimum beam energy is 375 keV.Conclusions:The conclusion is that this is the energy of minibeams that should be used in the preclinical studies.
Comparing the accuracy of four‐dimensional photon dose calculations with three‐dimensional calculations using moving and deforming phantoms
Authors: Vinogradskiy Yevgeniy Y. , Balter Peter , Followill David S. , Alvarez Paola E. , White R. Allen , Starkschall George 
Published: October 2009

Purpose:Four‐dimensional (4D) dose calculation algorithms, which explicitly incorporate respiratory motion in the calculation of doses, have the potential to improve the accuracy of dose calculations in thoracic treatment planning; however, they generally require greater computing power and resources than currently used for three‐dimensional (3D) dose calculations. The purpose of this work was to quantify the increase in accuracy of 4D dose calculations versus 3D dose calculations.Methods:The accuracy of each dose calculation algorithm was assessed using measurements made with two phantoms. Specifically, the authors used a rigid moving anthropomorphic thoracic phantom and an anthropomorphic thoracic phantom with a deformable lung insert. To incorporate a clinically relevant range of scenarios, they programed the phantoms to move and deform with two motion patterns: A sinusoidal motion pattern and an irregular motion pattern that was extracted from an actual patient's breathing profile. For each combination of phantom and motion pattern, three plans were created: A single‐beam plan, a multiple‐beam plan, and an intensity‐modulated radiation therapy plan. Doses were calculated using 4D dose calculation methods as well as conventional 3D dose calculation methods. The rigid moving and deforming phantoms were irradiated according to the three treatment plans and doses were measured using thermoluminescent dosimeters (TLDs) and radiochromic film. The accuracy of each dose calculation algorithm was assessed using measured‐to‐calculated TLD doses and a analysis.Results:No significant differences were observed between the measured‐to‐calculated TLD ratios among 4D and 3D dose calculations. The results revealed that 4D dose calculations had significantly greater percentage of pixels passing the criteria than 3D dose calculations.Conclusions:These results indicate no significant differences in the accuracy between the 4D and the 3D dose calculation methods inside the gross tumor volume. On the other hand, the film results demonstrated that the 4D dose calculations provided greater accuracy than 3D dose calculations in heterogeneous dose regions. The increase in accuracy of the 4D dose calculations was evident throughout the planning target volume.
Physical models, cross sections, and numerical approximations used inMCNPandGEANT4Monte Carlo codes for photon and electron absorbed fraction calculation
Authors: Yoriyaz Hélio , Moralles Maurício , de Tarso Dalledone Siqueira Paulo , da Costa Guimarães Carla , Belonsi Cintra Felipe , dos Santos Adimir 
Published: October 2009

Purpose:Radiopharmaceutical applications in nuclear medicine require a detailed dosimetry estimate of the radiation energy delivered to the human tissues. Over the past years, several publications addressed the problem of internal dose estimate in volumes of several sizes considering photon and electron sources. Most of them used Monte Carlo radiation transport codes. Despite the widespread use of these codes due to the variety of resources and potentials they offered to carry out dose calculations, several aspects like physical models, cross sections, and numerical approximations used in the simulations still remain an object of study. Accurate dose estimate depends on the correct selection of a set of simulation options that should be carefully chosen. This article presents an analysis of several simulation options provided by two of the most used codes worldwide:MCNPandGEANT4.Methods:For this purpose, comparisons of absorbed fraction estimates obtained with different physical models, cross sections, and numerical approximations are presented for spheres of several sizes and composed as five different biological tissues.Results:Considerable discrepancies have been found in some cases not only between the different codes but also between different cross sections and algorithms in the same code. Maximum differences found between the two codes are 5.0% and 10%, respectively, for photons and electrons.Conclusion:Even for simple problems as spheres and uniform radiation sources, the set of parameters chosen by any Monte Carlo code significantly affects the final results of a simulation, demonstrating the importance of the correct choice of parameters in the simulation.
More than 10 years experience of beam monitoring with the Gantry 1 spot scanning proton therapy facility at PSI
Authors: Lin Shixiong , Boehringer Terence , Coray Adolf , Grossmann Martin , Pedroni Eros 
Published: October 2009

Purpose:The beam monitoring equipments developed for the first PSI spot scanning proton therapy facility, Gantry 1, have been successfully used for more than 10 years. The purpose of this article is to summarize the author's experience in the beam monitoring technique for dynamic proton scanning.Methods:The spot dose delivery and verification use two independent beam monitoring and computer systems. In this article, the detector construction, electronic system, dosimetry, and quality assurance results are described in detail. The beam flux monitor is calibrated with a Faraday cup. The beam position monitoring is realized by measuring the magnetic fields of deflection magnets with Hall probes before applying the spot and by checking the beam position and width with an ionization strip chamber after the spot delivery.Results:The results of thimble ionization chamber dosimetry measurements are reproducible (with a mean deviation of less than 1% and a standard deviation of 1%). The resolution in the beam position measurement is of the order of a tenth of a millimeter. The tolerance of the beam position delivery and monitoring during scanning is less than 1.5 mm.Conclusions:The experiences gained with the successful operation of Gantry 1 represent a unique and solid background for the development of a new system, Gantry 2, in order to perform new advanced scanning techniques.
Photon counting multienergy x‐ray imaging: Effect of the characteristic x rays on detector performance
Authors: Shikhaliev Polad M. , Fritz Shannon G. , Chapman John W. 
Published: October 2009

Purpose:The purpose of this work was to investigate the effect of characteristic x rays on the performance of photon counting detectors for multienergy x‐ray imaging. X‐ray and CT systems with photon counting detectors have compelling advantages compared to energy integrating detectors, and cadmium zinc telluride (CZT) detector is the detector of choice. However, current CZT detectors exhibit several limitations that hamper their practical applications. These limitations include hole trapping, high leakage current, and charge sharing between detector pixels. Charge sharing occurs due to the diffusion of charge when it drifts toward the pixel electrodes. It also occurs due to nonlocal reabsorption of characteristic and scattered x rays created in the detector volume. Hole trapping, leakage current, and charge diffusion may potentially have technical solutions. Characteristic x‐ray escape and scatter, however, are fundamental in nature and cannot be easily addressed. The x‐ray scatter in the CZT material is small at photon energies used in x‐ray imaging. Therefore, the remaining major factor is characteristic x ray.Methods:Monte Carlo simulations were used for this study. An experimental photon counting multienergy x‐ray imaging system was used to compare simulations to experimental results. An x‐ray spectrum at 120 kVp tube voltage was used. The x‐ray energy range was split into five subregions (energy bins) and Monte Carlo simulations were performed at average x‐ray energies corresponding to these energy bins. The detector pixel size was changed within the 0.1–1 mm range, which covered all possible applications including radiography and CT imaging. The pixel shapes included square and strip pixels. For strip pixels, tilted angle irradiation of the CZT detector was also investigated.Results:The characteristic x rays escaped the pixels in approximately 70% of all x‐ray interactions for the smallest pixel size of 0.1 mm. The escape fraction decreased to 20% for the largest pixel size of 1 mm. All escape fractions, for all pixel sizes, at five energies, for square and strip pixels, and at three tilt angles were calculated and presented in tables. Simulated and measured spectra at 120 kVp were compared.Conclusions:Characteristic x‐ray escape deteriorates energy and spatial resolution, particularly for small pixel sizes. Correction methods should be developed based on the results of the simulations and experimental study.