Science.gov

Sample records for adult human phantoms

  1. Deformable adult human phantoms for radiation protection dosimetry: anthropometric data representing size distributions of adult worker populations and software algorithms.

    PubMed

    Na, Yong Hum; Zhang, Binquan; Zhang, Juying; Caracappa, Peter F; Xu, X George

    2010-07-01

    Computational phantoms representing workers and patients are essential in estimating organ doses from various occupational radiation exposures and medical procedures. Nearly all existing phantoms, however, were purposely designed to match internal and external anatomical features of the Reference Man as defined by the International Commission on Radiological Protection (ICRP). To reduce uncertainty in dose calculations caused by anatomical variations, a new generation of phantoms of varying organ and body sizes is needed. This paper presents detailed anatomical data in tables and graphs that are used to design such size-adjustable phantoms representing a range of adult individuals in terms of the body height, body weight and internal organ volume/mass. Two different sets of information are used to derive the phantom sets: (1) individual internal organ size and volume/mass distribution data derived from the recommendations of the ICRP in Publications 23 and 89 and (2) whole-body height and weight percentile data from the National Health and Nutrition Examination Survey (NHANES 1999-2002). The NHANES height and weight data for 19 year old males and females are used to estimate the distributions of individuals' size, which is unknown, that corresponds to the ICRP organ and tissue distributions. This paper then demonstrates the usage of these anthropometric data in the development of deformable anatomical phantoms. A pair of phantoms--modeled entirely in mesh surfaces--of the adult male and female, RPI-adult male (AM) and RPI-adult female (AF) are used as the base for size-adjustable phantoms. To create percentile-specific phantoms from these two base phantoms, organ surface boundaries are carefully altered according to the tabulated anthropometric data. Software algorithms are developed to automatically match the organ volumes and masses with desired values. Finally, these mesh-based, percentile-specific phantoms are converted into voxel-based phantoms for Monte Carlo

  2. Deformable adult human phantoms for radiation protection dosimetry: anthropometric data representing size distributions of adult worker populations and software algorithms

    NASA Astrophysics Data System (ADS)

    Hum Na, Yong; Zhang, Binquan; Zhang, Juying; Caracappa, Peter F.; Xu, X. George

    2010-07-01

    Computational phantoms representing workers and patients are essential in estimating organ doses from various occupational radiation exposures and medical procedures. Nearly all existing phantoms, however, were purposely designed to match internal and external anatomical features of the Reference Man as defined by the International Commission on Radiological Protection (ICRP). To reduce uncertainty in dose calculations caused by anatomical variations, a new generation of phantoms of varying organ and body sizes is needed. This paper presents detailed anatomical data in tables and graphs that are used to design such size-adjustable phantoms representing a range of adult individuals in terms of the body height, body weight and internal organ volume/mass. Two different sets of information are used to derive the phantom sets: (1) individual internal organ size and volume/mass distribution data derived from the recommendations of the ICRP in Publications 23 and 89 and (2) whole-body height and weight percentile data from the National Health and Nutrition Examination Survey (NHANES 1999-2002). The NHANES height and weight data for 19 year old males and females are used to estimate the distributions of individuals' size, which is unknown, that corresponds to the ICRP organ and tissue distributions. This paper then demonstrates the usage of these anthropometric data in the development of deformable anatomical phantoms. A pair of phantoms—modeled entirely in mesh surfaces—of the adult male and female, RPI-adult male (AM) and RPI-adult female (AF) are used as the base for size-adjustable phantoms. To create percentile-specific phantoms from these two base phantoms, organ surface boundaries are carefully altered according to the tabulated anthropometric data. Software algorithms are developed to automatically match the organ volumes and masses with desired values. Finally, these mesh-based, percentile-specific phantoms are converted into voxel-based phantoms for Monte

  3. FASH and MASH: female and male adult human phantoms based on polygon mesh surfaces: II. Dosimetric calculations

    NASA Astrophysics Data System (ADS)

    Kramer, R.; Cassola, V. F.; Khoury, H. J.; Vieira, J. W.; de Melo Lima, V. J.; Robson Brown, K.

    2010-01-01

    Female and male adult human phantoms, called FASH (Female Adult meSH) and MASH (Male Adult meSH), have been developed in the first part of this study using 3D animation software and anatomical atlases to replace the image-based FAX06 and the MAX06 voxel phantoms. 3D modelling methods allow for phantom development independent from medical images of patients, volunteers or cadavers. The second part of this study investigates the dosimetric implications for organ and tissue equivalent doses due to the anatomical differences between the new and the old phantoms. These differences are mainly caused by the supine position of human bodies during scanning in order to acquire digital images for voxel phantom development. Compared to an upright standing person, in image-based voxel phantoms organs are often coronally shifted towards the head and sometimes the sagittal diameter of the trunk is reduced by a gravitational change of the fat distribution. In addition, volumes of adipose and muscle tissue shielding internal organs are sometimes too small, because adaptation of organ volumes to ICRP-based organ masses often occurs at the expense of general soft tissues, such as adipose, muscle or unspecified soft tissue. These effects have dosimetric consequences, especially for partial body exposure, such as in x-ray diagnosis, but also for whole body external exposure and for internal exposure. Using the EGSnrc Monte Carlo code, internal and external exposure to photons and electrons has been simulated with both pairs of phantoms. The results show differences between organ and tissue equivalent doses for the upright standing FASH/MASH and the image-based supine FAX06/MAX06 phantoms of up to 80% for external exposure and up to 100% for internal exposure. Similar differences were found for external exposure between FASH/MASH and REGINA/REX, the reference voxel phantoms of the International Commission on Radiological Protection. Comparison of effective doses for external photon

  4. FASH and MASH: female and male adult human phantoms based on polygon mesh surfaces: I. Development of the anatomy

    NASA Astrophysics Data System (ADS)

    Cassola, V. F.; de Melo Lima, V. J.; Kramer, R.; Khoury, H. J.

    2010-01-01

    Among computational models, voxel phantoms based on computer tomographic (CT), nuclear magnetic resonance (NMR) or colour photographic images of patients, volunteers or cadavers have become popular in recent years. Although being true to nature representations of scanned individuals, voxel phantoms have limitations, especially when walled organs have to be segmented or when volumes of organs or body tissues, like adipose, have to be changed. Additionally, the scanning of patients or volunteers is usually made in supine position, which causes a shift of internal organs towards the ribcage, a compression of the lungs and a reduction of the sagittal diameter especially in the abdominal region compared to the regular anatomy of a person in the upright position, which in turn can influence organ and tissue absorbed or equivalent dose estimates. This study applies tools developed recently in the areas of computer graphics and animated films to the creation and modelling of 3D human organs, tissues, skeletons and bodies based on polygon mesh surfaces. Female and male adult human phantoms, called FASH (Female Adult meSH) and MASH (Male Adult meSH), have been designed using software, such as MakeHuman, Blender, Binvox and ImageJ, based on anatomical atlases, observing at the same time organ masses recommended by the International Commission on Radiological Protection for the male and female reference adult in report no 89. 113 organs, bones and tissues have been modelled in the FASH and the MASH phantoms representing locations for adults in standing posture. Most organ and tissue masses of the voxelized versions agree with corresponding data from ICRP89 within a margin of 2.6%. Comparison with the mesh-based male RPI_AM and female RPI_AF phantoms shows differences with respect to the material used, to the software and concepts applied, and to the anatomies created.

  5. MAX06 and FAX06: update of two adult human phantoms for radiation protection dosimetry

    NASA Astrophysics Data System (ADS)

    Kramer, R.; Khoury, H. J.; Vieira, J. W.; Lima, V. J. M.

    2006-07-01

    The International Commission on Radiological Protection (ICRP) is currently preparing new recommendations which will replace those released in ICRP 1991, 1990 Recommendations of the ICRP ICRP Publication 60 (Oxford: Pergamon). The draft report previews a change for the effective dose with respect to the number of organs and tissues to be included in its calculation. In the future, adipose tissue, connective tissue, the extrathoracic airways, the gall bladder, the heart wall, the lymphatic nodes, the prostate and the salivary glands have to be taken into account for the determination of the effective dose. This study reports on a second segmentation of the recently introduced male adult voxel (MAX) and female adult voxel (FAX) phantoms with regard to the new organs and tissues, but also presents a revised representation of the skeletons, which had not been adjusted to ICRP-based volumes in the first release of the two phantoms.

  6. Standing adult human phantoms based on 10th, 50th and 90th mass and height percentiles of male and female Caucasian populations

    NASA Astrophysics Data System (ADS)

    Cassola, V. F.; Milian, F. M.; Kramer, R.; de Oliveira Lira, C. A. B.; Khoury, H. J.

    2011-07-01

    Computational anthropomorphic human phantoms are useful tools developed for the calculation of absorbed or equivalent dose to radiosensitive organs and tissues of the human body. The problem is, however, that, strictly speaking, the results can be applied only to a person who has the same anatomy as the phantom, while for a person with different body mass and/or standing height the data could be wrong. In order to improve this situation for many areas in radiological protection, this study developed 18 anthropometric standing adult human phantoms, nine models per gender, as a function of the 10th, 50th and 90th mass and height percentiles of Caucasian populations. The anthropometric target parameters for body mass, standing height and other body measures were extracted from PeopleSize, a well-known software package used in the area of ergonomics. The phantoms were developed based on the assumption of a constant body-mass index for a given mass percentile and for different heights. For a given height, increase or decrease of body mass was considered to reflect mainly the change of subcutaneous adipose tissue mass, i.e. that organ masses were not changed. Organ mass scaling as a function of height was based on information extracted from autopsy data. The methods used here were compared with those used in other studies, anatomically as well as dosimetrically. For external exposure, the results show that equivalent dose decreases with increasing body mass for organs and tissues located below the subcutaneous adipose tissue layer, such as liver, colon, stomach, etc, while for organs located at the surface, such as breasts, testes and skin, the equivalent dose increases or remains constant with increasing body mass due to weak attenuation and more scatter radiation caused by the increasing adipose tissue mass. Changes of standing height have little influence on the equivalent dose to organs and tissues from external exposure. Specific absorbed fractions (SAFs) have also

  7. Neutron dosimetry in organs of an adult human phantom using linacs with multileaf collimator in radiotherapy treatments

    SciTech Connect

    Martinez-Ovalle, S. A.; Barquero, R.; Gomez-Ros, J. M.; Lallena, A. M.

    2012-05-15

    Purpose: To calculate absorbed doses due to neutrons in 87 organs/tissues for anthropomorphic phantoms, irradiated in position supine (head first into the gantry) with orientations anteroposterior (AP) and right-left (RLAT) with a 18 MV accelerator. Conversion factors from monitor units to {mu}Gy per neutron in organs, equivalent doses in organs/tissues, and effective doses, which permit to quantify stochastic risks, are estimated. Methods: MAX06 and FAX06 phantoms were modeled with MCNPX and irradiated with a 18 MV Varian Clinac 2100C/D accelerator whose geometry included a multileaf collimator. Two actual fields of a pelvic treatment were simulated using electron-photon-neutron coupled transport. Absorbed doses due to neutrons were estimated from kerma. Equivalent doses were estimated using the radiation weighting factor corresponding to an average incident neutron energy 0.47 MeV. Statistical uncertainties associated to absorbed doses, as calculated by MCNPX, were also obtained. Results: Largest doses were absorbed in shallowest (with respect to the neutron pathway) organs. In {mu}GyMU{sup -1}, values of 2.66 (for penis) and 2.33 (for testes) were found in MAX06, and 1.68 (for breasts), 1.05 (for lenses of eyes), and 0.94 (for sublingual salivary glands) in FAX06, in AP orientation. In RLAT, the largest doses were found for bone tissues (leg) just at the entrance of the beam in the body (right side in our case). Values, in {mu}GyMU{sup -1}, of 1.09 in upper leg bone right spongiosa, for MAX06, and 0.63 in mandible spongiosa, for FAX06, were found. Except for gonads, liver, and stomach wall, equivalent doses found for FAX06 were, in both orientations, higher than for MAX06. Equivalent doses in AP are higher than in RLAT for all organs/tissues other than brain and liver. Effective doses of 12.6 and 4.1 {mu}SvMU{sup -1} were found for AP and RLAT, respectively. The organs/tissues with larger relative contributions to the effective dose were testes and breasts, in

  8. Construction of Taiwanese Adult Reference Phantoms for Internal Dose Evaluation.

    PubMed

    Chang, Shu-Jun; Hung, Shih-Yen; Liu, Yan-Lin; Jiang, Shiang-Huei

    2016-01-01

    In the internal dose evaluation, the specific absorbed fraction (SAF) and S-value are calculated from the reference phantom based on Caucasian data. The differences in height and weight between Caucasian and Asian may lead to inaccurate dose estimation. In this study, we developed the Taiwanese reference phantoms. 40 volunteers were recruited. Magnetic resonance images (MRI) were obtained, and the contours of 15 organs were drawn. The Taiwanese reference man (TRM) and Taiwanese reference woman (TRW) were constructed. For the SAF calculation, the differences in the self-absorption SAF (self-SAF) between the TRM, TRW, and Oak Ridge National Laboratory (ORNL) adult phantom were less than 10% when the difference in organ mass was less than 20%. The average SAF from liver to pancreas of TRM was 38% larger than that of the ORNL adult phantom, and the result of TRW was 2.02 times higher than that of the ORNL adult phantom. For the S-value calculation, the ratios of TRW and ORNL adult phantom ranged from 0.91 to 1.57, and the ratios of TRM and ORNL adult phantom ranged from 1.04 to 2.29. The SAF and S-value results were dominantly affected by the height, weight, organ mass, and geometric relationship between organs. By using the TRM and TRW, the accuracy of internal dose evaluation can be increased for radiation protection and nuclear medicine.

  9. Construction of Taiwanese Adult Reference Phantoms for Internal Dose Evaluation

    PubMed Central

    Chang, Shu-Jun; Hung, Shih-Yen; Liu, Yan-Lin; Jiang, Shiang-Huei

    2016-01-01

    In the internal dose evaluation, the specific absorbed fraction (SAF) and S-value are calculated from the reference phantom based on Caucasian data. The differences in height and weight between Caucasian and Asian may lead to inaccurate dose estimation. In this study, we developed the Taiwanese reference phantoms. 40 volunteers were recruited. Magnetic resonance images (MRI) were obtained, and the contours of 15 organs were drawn. The Taiwanese reference man (TRM) and Taiwanese reference woman (TRW) were constructed. For the SAF calculation, the differences in the self-absorption SAF (self-SAF) between the TRM, TRW, and Oak Ridge National Laboratory (ORNL) adult phantom were less than 10% when the difference in organ mass was less than 20%. The average SAF from liver to pancreas of TRM was 38% larger than that of the ORNL adult phantom, and the result of TRW was 2.02 times higher than that of the ORNL adult phantom. For the S-value calculation, the ratios of TRW and ORNL adult phantom ranged from 0.91 to 1.57, and the ratios of TRM and ORNL adult phantom ranged from 1.04 to 2.29. The SAF and S-value results were dominantly affected by the height, weight, organ mass, and geometric relationship between organs. By using the TRM and TRW, the accuracy of internal dose evaluation can be increased for radiation protection and nuclear medicine. PMID:27618708

  10. Construction of Taiwanese Adult Reference Phantoms for Internal Dose Evaluation.

    PubMed

    Chang, Shu-Jun; Hung, Shih-Yen; Liu, Yan-Lin; Jiang, Shiang-Huei

    2016-01-01

    In the internal dose evaluation, the specific absorbed fraction (SAF) and S-value are calculated from the reference phantom based on Caucasian data. The differences in height and weight between Caucasian and Asian may lead to inaccurate dose estimation. In this study, we developed the Taiwanese reference phantoms. 40 volunteers were recruited. Magnetic resonance images (MRI) were obtained, and the contours of 15 organs were drawn. The Taiwanese reference man (TRM) and Taiwanese reference woman (TRW) were constructed. For the SAF calculation, the differences in the self-absorption SAF (self-SAF) between the TRM, TRW, and Oak Ridge National Laboratory (ORNL) adult phantom were less than 10% when the difference in organ mass was less than 20%. The average SAF from liver to pancreas of TRM was 38% larger than that of the ORNL adult phantom, and the result of TRW was 2.02 times higher than that of the ORNL adult phantom. For the S-value calculation, the ratios of TRW and ORNL adult phantom ranged from 0.91 to 1.57, and the ratios of TRM and ORNL adult phantom ranged from 1.04 to 2.29. The SAF and S-value results were dominantly affected by the height, weight, organ mass, and geometric relationship between organs. By using the TRM and TRW, the accuracy of internal dose evaluation can be increased for radiation protection and nuclear medicine. PMID:27618708

  11. Hybrid computational phantoms representing the reference adult male and adult female: construction and applications for retrospective dosimetry.

    PubMed

    Hurtado, Jorge L; Lee, Choonsik; Lodwick, Daniel; Goede, Timothy; Williams, Jonathan L; Bolch, Wesley E

    2012-03-01

    Currently, two classes of computational phantoms have been developed for dosimetry calculation: (1) stylized (or mathematical) and (2) voxel (or tomographic) phantoms describing human anatomy through mathematical surface equations and 3D voxel matrices, respectively. Mathematical surface equations in stylized phantoms are flexible, but the resulting anatomy is not as realistic. Voxel phantoms display far better anatomical realism, but they are limited in terms of their ability to alter organ shape, position, and depth, as well as body posture. A new class of computational phantoms called hybrid phantoms takes advantage of the best features of stylized and voxel phantoms-flexibility and anatomical realism, respectively. In the current study, hybrid computational phantoms representing the adult male and female reference anatomy and anthropometry are presented. These phantoms serve as the starting framework for creating patient or worker sculpted whole-body phantoms for retrospective dose reconstruction. Contours of major organs and tissues were converted or segmented from computed tomography images of a 36-y-old Korean volunteer and a 25-y-old U.S. female patient, respectively, with supplemental high-resolution CT images of the cranium. Polygon mesh models for the major organs and tissues were reconstructed and imported into Rhinoceros™ for non-uniform rational B-spline (NURBS) surface modeling. The resulting NURBS/polygon mesh models representing body contour and internal anatomy were matched to anthropometric data and reference organ mass data provided by Centers for Disease Control and Prevention and International Commission on Radiation Protection, respectively. Finally, two hybrid adult male and female phantoms were completed where a total of eight anthropometric data categories were matched to standard values within 4% and organ volumes matched to ICRP data within 1% with the exception of total skin. The hybrid phantoms were voxelized from the NURBS phantoms

  12. Construction of Chinese adult male phantom library and its application in the virtual calibration of in vivo measurement

    NASA Astrophysics Data System (ADS)

    Chen, Yizheng; Qiu, Rui; Li, Chunyan; Wu, Zhen; Li, Junli

    2016-03-01

    In vivo measurement is a main method of internal contamination evaluation, particularly for large numbers of people after a nuclear accident. Before the practical application, it is necessary to obtain the counting efficiency of the detector by calibration. The virtual calibration based on Monte Carlo simulation usually uses the reference human computational phantom, and the morphological difference between the monitored personnel with the calibrated phantom may lead to the deviation of the counting efficiency. Therefore, a phantom library containing a wide range of heights and total body masses is needed. In this study, a Chinese reference adult male polygon surface (CRAM_S) phantom was constructed based on the CRAM voxel phantom, with the organ models adjusted to match the Chinese reference data. CRAMS phantom was then transformed to sitting posture for convenience in practical monitoring. Referring to the mass and height distribution of the Chinese adult male, a phantom library containing 84 phantoms was constructed by deforming the reference surface phantom. Phantoms in the library have 7 different heights ranging from 155 cm to 185 cm, and there are 12 phantoms with different total body masses in each height. As an example of application, organ specific and total counting efficiencies of Ba-133 were calculated using the MCNPX code, with two series of phantoms selected from the library. The influence of morphological variation on the counting efficiency was analyzed. The results show only using the reference phantom in virtual calibration may lead to an error of 68.9% for total counting efficiency. Thus the influence of morphological difference on virtual calibration can be greatly reduced using the phantom library with a wide range of masses and heights instead of a single reference phantom.

  13. Development of realistic physical breast phantoms matched to virtual breast phantoms based on human subject data

    SciTech Connect

    Kiarashi, Nooshin; Nolte, Adam C.; Sturgeon, Gregory M.; Ghate, Sujata V.; Segars, William P.; Nolte, Loren W.; Samei, Ehsan; and others

    2015-07-15

    Purpose: Physical phantoms are essential for the development, optimization, and evaluation of x-ray breast imaging systems. Recognizing the major effect of anatomy on image quality and clinical performance, such phantoms should ideally reflect the three-dimensional structure of the human breast. Currently, there is no commercially available three-dimensional physical breast phantom that is anthropomorphic. The authors present the development of a new suite of physical breast phantoms based on human data. Methods: The phantoms were designed to match the extended cardiac-torso virtual breast phantoms that were based on dedicated breast computed tomography images of human subjects. The phantoms were fabricated by high-resolution multimaterial additive manufacturing (3D printing) technology. The glandular equivalency of the photopolymer materials was measured relative to breast tissue-equivalent plastic materials. Based on the current state-of-the-art in the technology and available materials, two variations were fabricated. The first was a dual-material phantom, the Doublet. Fibroglandular tissue and skin were represented by the most radiographically dense material available; adipose tissue was represented by the least radiographically dense material. The second variation, the Singlet, was fabricated with a single material to represent fibroglandular tissue and skin. It was subsequently filled with adipose-equivalent materials including oil, beeswax, and permanent urethane-based polymer. Simulated microcalcification clusters were further included in the phantoms via crushed eggshells. The phantoms were imaged and characterized visually and quantitatively. Results: The mammographic projections and tomosynthesis reconstructed images of the fabricated phantoms yielded realistic breast background. The mammograms of the phantoms demonstrated close correlation with simulated mammographic projection images of the corresponding virtual phantoms. Furthermore, power

  14. All about FAX: a Female Adult voXel phantom for Monte Carlo calculation in radiation protection dosimetry.

    PubMed

    Kramer, R; Khoury, H J; Vieira, J W; Loureiro, E C M; Lima, V J M; Lima, F R A; Hoff, G

    2004-12-01

    The International Commission on Radiological Protection (ICRP) has created a task group on dose calculations, which, among other objectives, should replace the currently used mathematical MIRD phantoms by voxel phantoms. Voxel phantoms are based on digital images recorded from scanning of real persons by computed tomography or magnetic resonance imaging (MRI). Compared to the mathematical MIRD phantoms, voxel phantoms are true to the natural representations of a human body. Connected to a radiation transport code, voxel phantoms serve as virtual humans for which equivalent dose to organs and tissues from exposure to ionizing radiation can be calculated. The principal database for the construction of the FAX (Female Adult voXel) phantom consisted of 151 CT images recorded from scanning of trunk and head of a female patient, whose body weight and height were close to the corresponding data recommended by the ICRP in Publication 89. All 22 organs and tissues at risk, except for the red bone marrow and the osteogenic cells on the endosteal surface of bone ('bone surface'), have been segmented manually with a technique recently developed at the Departamento de Energia Nuclear of the UFPE in Recife, Brazil. After segmentation the volumes of the organs and tissues have been adjusted to agree with the organ and tissue masses recommended by ICRP for the Reference Adult Female in Publication 89. Comparisons have been made with the organ and tissue masses of the mathematical EVA phantom, as well as with the corresponding data for other female voxel phantoms. The three-dimensional matrix of the segmented images has eventually been connected to the EGS4 Monte Carlo code. Effective dose conversion coefficients have been calculated for exposures to photons, and compared to data determined for the mathematical MIRD-type phantoms, as well as for other voxel phantoms.

  15. Thermal human phantom for testing of millimeter wave cameras

    NASA Astrophysics Data System (ADS)

    Palka, Norbert; Ryniec, Radoslaw; Piszczek, Marek; Szustakowski, Mieczyslaw; Zyczkowski, Marek; Kowalski, Marcin

    2012-06-01

    Screening cameras working in millimetre band gain more and more interest among security society mainly due to their capability of finding items hidden under clothes. Performance of commercially available passive cameras is still limited due to not sufficient resolution and contrast in comparison to other wavelengths (visible or infrared range). Testing of such cameras usually requires some persons carrying guns, bombs or knives. Such persons can have different clothes or body temperature, what makes the measurements even more ambiguous. To avoid such situations we built a moving phantom of human body. The phantom consists of a polystyrene manikin which is covered with a number of small pipes with water. Pipes were next coated with a silicone "skin". The veins (pipes) are filled with water heated up to 37 C degrees to obtain the same temperature as human body. The phantom is made of non-metallic materials and is placed on a moving wirelessly-controlled platform with four wheels. The phantom can be dressed with a set of ordinary clothes and can be equipped with some dangerous (guns, bombs) and non-dangerous items. For tests we used a passive commercially available camera TS4 from ThruVision Systems Ltd. operating at 250 GHz. We compared the images taken from phantom and a man and we obtained good similarity both for naked as well as dressed man/phantom case. We also tested the phantom with different sets of clothes and hidden items and we got good conformity with persons.

  16. Measuring absorbed dose for i-CAT CBCT examinations in child, adolescent and adult phantoms

    PubMed Central

    Choi, E

    2015-01-01

    Objectives: Design and construct child and adolescent head phantoms to measure the absorbed doses imparted during dental CBCT and compare with the absorbed dose measured in an adult phantom. Methods: A child phantom was developed to represent the smallest patients receiving CBCT, usually for craniofacial developmental concerns, and an adolescent phantom was developed to represent healthy orthodontic patients. Absorbed doses were measured using a thimble ionization chamber for the custom-built child and adolescent phantoms and compared with measurements using a commercially available adult phantom. Imaging was performed with an i-CAT Next Generation (Imaging Sciences International, Hatfield, PA) CBCT using two different fields of view covering the craniofacial complex (130 mm high) or maxilla/mandible (60 mm high). Results: Measured absorbed doses varied depending on the location of the ionization chamber within the phantoms. For CBCT images obtained using the same protocol for all phantoms, the highest absorbed dose was measured in all locations of the small child phantom. The lowest absorbed dose was measured in the adult phantom. Conclusions: Images were obtained with the same protocol for the adult, adolescent and child phantoms. A consistent trend was observed with the highest absorbed dose being measured in the smallest phantom (child), while the lowest absorbed dose was measured in the largest phantom (adult). This study demonstrates the importance of child-sizing the dose by using dedicated paediatric protocols optimized for the imaging task, which is critical as children are more sensitive to harmful effects of radiation and have a longer life-span post-irradiation for radiation-induced symptoms to develop than do adults. PMID:25785822

  17. Specific absorbed fractions of electrons and photons for Rad-HUMAN phantom using Monte Carlo method

    NASA Astrophysics Data System (ADS)

    Wang, Wen; Cheng, Meng-Yun; Long, Peng-Cheng; Hu, Li-Qin

    2015-07-01

    The specific absorbed fractions (SAF) for self- and cross-irradiation are effective tools for the internal dose estimation of inhalation and ingestion intakes of radionuclides. A set of SAFs of photons and electrons were calculated using the Rad-HUMAN phantom, which is a computational voxel phantom of a Chinese adult female that was created using the color photographic image of the Chinese Visible Human (CVH) data set by the FDS Team. The model can represent most Chinese adult female anatomical characteristics and can be taken as an individual phantom to investigate the difference of internal dose with Caucasians. In this study, the emission of mono-energetic photons and electrons of 10 keV to 4 MeV energy were calculated using the Monte Carlo particle transport calculation code MCNP. Results were compared with the values from ICRP reference and ORNL models. The results showed that SAF from the Rad-HUMAN have similar trends but are larger than those from the other two models. The differences were due to the racial and anatomical differences in organ mass and inter-organ distance. The SAFs based on the Rad-HUMAN phantom provide an accurate and reliable data for internal radiation dose calculations for Chinese females. Supported by Strategic Priority Research Program of Chinese Academy of Sciences (XDA03040000), National Natural Science Foundation of China (910266004, 11305205, 11305203) and National Special Program for ITER (2014GB112001)

  18. Comparison of internal dosimetry factors for three classes of adult computational phantoms with emphasis on I-131 in the thyroid

    NASA Astrophysics Data System (ADS)

    Lamart, Stephanie; Bouville, Andre; Simon, Steven L.; Eckerman, Keith F.; Melo, Dunstana; Lee, Choonsik

    2011-11-01

    The S values for 11 major target organs for I-131 in the thyroid were compared for three classes of adult computational human phantoms: stylized, voxel and hybrid phantoms. In addition, we compared specific absorbed fractions (SAFs) with the thyroid as a source region over a broader photon energy range than the x- and gamma-rays of I-131. The S and SAF values were calculated for the International Commission on Radiological Protection (ICRP) reference voxel phantoms and the University of Florida (UF) hybrid phantoms by using the Monte Carlo transport method, while the S and SAF values for the Oak Ridge National Laboratory (ORNL) stylized phantoms were obtained from earlier publications. Phantoms in our calculations were for adults of both genders. The 11 target organs and tissues that were selected for the comparison of S values are brain, breast, stomach wall, small intestine wall, colon wall, heart wall, pancreas, salivary glands, thyroid, lungs and active marrow for I-131 and thyroid as a source region. The comparisons showed, in general, an underestimation of S values reported for the stylized phantoms compared to the values based on the ICRP voxel and UF hybrid phantoms and relatively good agreement between the S values obtained for the ICRP and UF phantoms. Substantial differences were observed for some organs between the three types of phantoms. For example, the small intestine wall of ICRP male phantom and heart wall of ICRP female phantom showed up to eightfold and fourfold greater S values, respectively, compared to the reported values for the ORNL phantoms. UF male and female phantoms also showed significant differences compared to the ORNL phantom, 4.0-fold greater for the small intestine wall and 3.3-fold greater for the heart wall. In our method, we directly calculated the S values without using the SAFs as commonly done. Hence, we sought to confirm the differences observed in our S values by comparing the SAFs among the phantoms with the thyroid as a

  19. Population of anatomically variable 4D XCAT adult phantoms for imaging research and optimization

    SciTech Connect

    Segars, W. P.; Bond, Jason; Frush, Jack; Hon, Sylvia; Eckersley, Chris; Samei, E.; Williams, Cameron H.; Frush, D.; Feng Jianqiao; Tward, Daniel J.; Ratnanather, J. T.; Miller, M. I.

    2013-04-15

    Purpose: The authors previously developed the 4D extended cardiac-torso (XCAT) phantom for multimodality imaging research. The XCAT consisted of highly detailed whole-body models for the standard male and female adult, including the cardiac and respiratory motions. In this work, the authors extend the XCAT beyond these reference anatomies by developing a series of anatomically variable 4D XCAT adult phantoms for imaging research, the first library of 4D computational phantoms. Methods: The initial anatomy of each phantom was based on chest-abdomen-pelvis computed tomography data from normal patients obtained from the Duke University database. The major organs and structures for each phantom were segmented from the corresponding data and defined using nonuniform rational B-spline surfaces. To complete the body, the authors manually added on the head, arms, and legs using the original XCAT adult male and female anatomies. The structures were scaled to best match the age and anatomy of the patient. A multichannel large deformation diffeomorphic metric mapping algorithm was then used to calculate the transform from the template XCAT phantom (male or female) to the target patient model. The transform was applied to the template XCAT to fill in any unsegmented structures within the target phantom and to implement the 4D cardiac and respiratory models in the new anatomy. Each new phantom was refined by checking for anatomical accuracy via inspection of the models. Results: Using these methods, the authors created a series of computerized phantoms with thousands of anatomical structures and modeling cardiac and respiratory motions. The database consists of 58 (35 male and 23 female) anatomically variable phantoms in total. Like the original XCAT, these phantoms can be combined with existing simulation packages to simulate realistic imaging data. Each new phantom contains parameterized models for the anatomy and the cardiac and respiratory motions and can, therefore, serve

  20. Human torso phantom for imaging of heart with realistic modes of cardiac and respiratory motion

    DOEpatents

    Boutchko, Rostyslav; Balakrishnan, Karthikayan; Gullberg, Grant T; O& #x27; Neil, James P

    2013-09-17

    A human torso phantom and its construction, wherein the phantom mimics respiratory and cardiac cycles in a human allowing acquisition of medical imaging data under conditions simulating patient cardiac and respiratory motion.

  1. Space radiation absorbed dose distribution in a human phantom.

    PubMed

    Badhwar, G D; Atwell, W; Badavi, F F; Yang, T C; Cleghorn, T F

    2002-01-01

    The radiation risk to astronauts has always been based on measurements using passive thermoluminescent dosimeters (TLDs). The skin dose is converted to dose equivalent using an average radiation quality factor based on model calculations. The radiological risk estimates, however, are based on organ and tissue doses. This paper describes results from the first space flight (STS-91, 51.65 degrees inclination and approximately 380 km altitude) of a fully instrumented Alderson Rando phantom torso (with head) to relate the skin dose to organ doses. Spatial distributions of absorbed dose in 34 1-inch-thick sections measured using TLDs are described. There is about a 30% change in dose as one moves from the front to the back of the phantom body. Small active dosimeters were developed specifically to provide time-resolved measurements of absorbed dose rates and quality factors at five organ locations (brain, thyroid, heart/lung, stomach and colon) inside the phantom. Using these dosimeters, it was possible to separate the trapped-proton and the galactic cosmic radiation components of the doses. A tissue-equivalent proportional counter (TEPC) and a charged-particle directional spectrometer (CPDS) were flown next to the phantom torso to provide data on the incident internal radiation environment. Accurate models of the shielding distributions at the site of the TEPC, the CPDS and a scalable Computerized Anatomical Male (CAM) model of the phantom torso were developed. These measurements provided a comprehensive data set to map the dose distribution inside a human phantom, and to assess the accuracy and validity of radiation transport models throughout the human body. The results show that for the conditions in the International Space Station (ISS) orbit during periods near the solar minimum, the ratio of the blood-forming organ dose rate to the skin absorbed dose rate is about 80%, and the ratio of the dose equivalents is almost one. The results show that the GCR model dose

  2. Space radiation absorbed dose distribution in a human phantom

    NASA Technical Reports Server (NTRS)

    Badhwar, G. D.; Atwell, W.; Badavi, F. F.; Yang, T. C.; Cleghorn, T. F.

    2002-01-01

    The radiation risk to astronauts has always been based on measurements using passive thermoluminescent dosimeters (TLDs). The skin dose is converted to dose equivalent using an average radiation quality factor based on model calculations. The radiological risk estimates, however, are based on organ and tissue doses. This paper describes results from the first space flight (STS-91, 51.65 degrees inclination and approximately 380 km altitude) of a fully instrumented Alderson Rando phantom torso (with head) to relate the skin dose to organ doses. Spatial distributions of absorbed dose in 34 1-inch-thick sections measured using TLDs are described. There is about a 30% change in dose as one moves from the front to the back of the phantom body. Small active dosimeters were developed specifically to provide time-resolved measurements of absorbed dose rates and quality factors at five organ locations (brain, thyroid, heart/lung, stomach and colon) inside the phantom. Using these dosimeters, it was possible to separate the trapped-proton and the galactic cosmic radiation components of the doses. A tissue-equivalent proportional counter (TEPC) and a charged-particle directional spectrometer (CPDS) were flown next to the phantom torso to provide data on the incident internal radiation environment. Accurate models of the shielding distributions at the site of the TEPC, the CPDS and a scalable Computerized Anatomical Male (CAM) model of the phantom torso were developed. These measurements provided a comprehensive data set to map the dose distribution inside a human phantom, and to assess the accuracy and validity of radiation transport models throughout the human body. The results show that for the conditions in the International Space Station (ISS) orbit during periods near the solar minimum, the ratio of the blood-forming organ dose rate to the skin absorbed dose rate is about 80%, and the ratio of the dose equivalents is almost one. The results show that the GCR model dose

  3. Space radiation absorbed dose distribution in a human phantom.

    PubMed

    Badhwar, G D; Atwell, W; Badavi, F F; Yang, T C; Cleghorn, T F

    2002-01-01

    The radiation risk to astronauts has always been based on measurements using passive thermoluminescent dosimeters (TLDs). The skin dose is converted to dose equivalent using an average radiation quality factor based on model calculations. The radiological risk estimates, however, are based on organ and tissue doses. This paper describes results from the first space flight (STS-91, 51.65 degrees inclination and approximately 380 km altitude) of a fully instrumented Alderson Rando phantom torso (with head) to relate the skin dose to organ doses. Spatial distributions of absorbed dose in 34 1-inch-thick sections measured using TLDs are described. There is about a 30% change in dose as one moves from the front to the back of the phantom body. Small active dosimeters were developed specifically to provide time-resolved measurements of absorbed dose rates and quality factors at five organ locations (brain, thyroid, heart/lung, stomach and colon) inside the phantom. Using these dosimeters, it was possible to separate the trapped-proton and the galactic cosmic radiation components of the doses. A tissue-equivalent proportional counter (TEPC) and a charged-particle directional spectrometer (CPDS) were flown next to the phantom torso to provide data on the incident internal radiation environment. Accurate models of the shielding distributions at the site of the TEPC, the CPDS and a scalable Computerized Anatomical Male (CAM) model of the phantom torso were developed. These measurements provided a comprehensive data set to map the dose distribution inside a human phantom, and to assess the accuracy and validity of radiation transport models throughout the human body. The results show that for the conditions in the International Space Station (ISS) orbit during periods near the solar minimum, the ratio of the blood-forming organ dose rate to the skin absorbed dose rate is about 80%, and the ratio of the dose equivalents is almost one. The results show that the GCR model dose

  4. Development of skeletal system for mesh-type ICRP reference adult phantoms

    NASA Astrophysics Data System (ADS)

    Yeom, Yeon Soo; Wang, Zhao Jun; Tat Nguyen, Thang; Kim, Han Sung; Choi, Chansoo; Han, Min Cheol; Kim, Chan Hyeong; Lee, Jai Ki; Chung, Beom Sun; Zankl, Maria; Petoussi-Henss, Nina; Bolch, Wesley E.; Lee, Choonsik

    2016-10-01

    The reference adult computational phantoms of the international commission on radiological protection (ICRP) described in Publication 110 are voxel-type computational phantoms based on whole-body computed tomography (CT) images of adult male and female patients. The voxel resolutions of these phantoms are in the order of a few millimeters and smaller tissues such as the eye lens, the skin, and the walls of some organs cannot be properly defined in the phantoms, resulting in limitations in dose coefficient calculations for weakly penetrating radiations. In order to address the limitations of the ICRP-110 phantoms, an ICRP Task Group has been recently formulated and the voxel phantoms are now being converted to a high-quality mesh format. As a part of the conversion project, in the present study, the skeleton models, one of the most important and complex organs of the body, were constructed. The constructed skeleton models were then tested by calculating red bone marrow (RBM) and endosteum dose coefficients (DCs) for broad parallel beams of photons and electrons and comparing the calculated values with those of the original ICRP-110 phantoms. The results show that for the photon exposures, there is a generally good agreement in the DCs between the mesh-type phantoms and the original voxel-type ICRP-110 phantoms; that is, the dose discrepancies were less than 7% in all cases except for the 0.03 MeV cases, for which the maximum difference was 14%. On the other hand, for the electron exposures (⩽4 MeV), the DCs of the mesh-type phantoms deviate from those of the ICRP-110 phantoms by up to ~1600 times at 0.03 MeV, which is indeed due to the improvement of the skeletal anatomy of the developed skeleton mesh models.

  5. Radiation dose evaluation of dental cone beam computed tomography using an anthropomorphic adult head phantom

    NASA Astrophysics Data System (ADS)

    Wu, Jay; Shih, Cheng-Ting; Ho, Chang-hung; Liu, Yan-Lin; Chang, Yuan-Jen; Min Chao, Max; Hsu, Jui-Ting

    2014-11-01

    Dental cone beam computed tomography (CBCT) provides high-resolution tomographic images and has been gradually used in clinical practice. Thus, it is important to examine the amount of radiation dose resulting from dental CBCT examinations. In this study, we developed an in-house anthropomorphic adult head phantom to evaluate the level of effective dose. The anthropomorphic phantom was made of acrylic and filled with plaster to replace the bony tissue. The contour of the head was extracted from a set of adult computed tomography (CT) images. Different combinations of the scanning parameters of CBCT were applied. Thermoluminescent dosimeters (TLDs) were used to measure the absorbed doses at 19 locations in the head and neck regions. The effective doses measured using the proposed phantom at 65, 75, and 85 kVp in the D-mode were 72.23, 100.31, and 134.29 μSv, respectively. In the I-mode, the effective doses were 108.24, 190.99, and 246.48 μSv, respectively. The maximum percent error between the doses measured by the proposed phantom and the Rando phantom was l4.90%. Therefore, the proposed anthropomorphic adult head phantom is applicable for assessing the radiation dose resulting from clinical dental CBCT.

  6. Space Radiation Absorbed Dose Distribution in a Human Phantom Torso

    NASA Technical Reports Server (NTRS)

    Badhwar, G. D.; Yang, T.; Atwell, W.

    2000-01-01

    The flight of a human phantom torso with head that containing active dosimeters at 5 organ sites and 1400 TLDs distributed in 34 1" thick sections is described. Experimental dose rates and quality factors are compared with calculations for shielding distributions at the sites using the Computerized Anatomical Male (CAM) model. The measurements were complemented with those obtained from other instruments. These results have provided the most comprehensive data set to map the dose distribution inside a human and to assess the accuracy of radiation transport models and astronaut radiation risk.

  7. The UF family of hybrid phantoms of the developing human fetus for computational radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Maynard, Matthew R.; Geyer, John W.; Aris, John P.; Shifrin, Roger Y.; Bolch, Wesley

    2011-08-01

    Historically, the development of computational phantoms for radiation dosimetry has primarily been directed at capturing and representing adult and pediatric anatomy, with less emphasis devoted to models of the human fetus. As concern grows over possible radiation-induced cancers from medical and non-medical exposures of the pregnant female, the need to better quantify fetal radiation doses, particularly at the organ-level, also increases. Studies such as the European Union's SOLO (Epidemiological Studies of Exposed Southern Urals Populations) hope to improve our understanding of cancer risks following chronic in utero radiation exposure. For projects such as SOLO, currently available fetal anatomic models do not provide sufficient anatomical detail for organ-level dose assessment. To address this need, two fetal hybrid computational phantoms were constructed using high-quality magnetic resonance imaging and computed tomography image sets obtained for two well-preserved fetal specimens aged 11.5 and 21 weeks post-conception. Individual soft tissue organs, bone sites and outer body contours were segmented from these images using 3D-DOCTOR™ and then imported to the 3D modeling software package Rhinoceros™ for further modeling and conversion of soft tissue organs, certain bone sites and outer body contours to deformable non-uniform rational B-spline surfaces. The two specimen-specific phantoms, along with a modified version of the 38 week UF hybrid newborn phantom, comprised a set of base phantoms from which a series of hybrid computational phantoms was derived for fetal ages 8, 10, 15, 20, 25, 30, 35 and 38 weeks post-conception. The methodology used to construct the series of phantoms accounted for the following age-dependent parameters: (1) variations in skeletal size and proportion, (2) bone-dependent variations in relative levels of bone growth, (3) variations in individual organ masses and total fetal masses and (4) statistical percentile variations in

  8. S values for 131I based on the ICRP adult voxel phantoms.

    PubMed

    Lamart, Stephanie; Simon, Steven L; Bouville, Andre; Moroz, Brian E; Lee, Choonsik

    2016-01-01

    To improve the estimates of organ doses from nuclear medicine procedures using (131)I, the authors calculated a comprehensive set of (131)I S values, defined as absorbed doses in target tissues per unit of nuclear transition in source regions, for different source and target combinations. The authors used the latest reference adult male and female voxel phantoms published by the International Commission on Radiological Protection (ICRP Publication 110) and the (131)I photon and electron spectra from the ICRP Publication 107 to perform Monte Carlo radiation transport calculations using MCNPX2.7 to compute the S values. For each phantom, the authors simulated 55 source regions with an assumed uniform distribution of (131)I. They computed the S values for 42 target tissues directly, without calculating specific absorbed fractions. From these calculations, the authors derived a comprehensive set of S values for (131)I for 55 source regions and 42 target tissues in the ICRP male and female voxel phantoms. Compared with the stylised phantoms from Oak Ridge National Laboratory (ORNL) that consist of 22 source regions and 24 target regions, the new data set includes 1662 additional S values corresponding to additional combinations of source-target tissues that are not available in the stylised phantoms. In a comparison of S values derived from the ICRP and ORNL phantoms, the authors found that the S values to the radiosensitive tissues in the ICRP phantoms were 1.1 (median, female) and 1.3 (median, male) times greater than the values based on the ORNL phantoms. However, for several source-target pairs, the difference was up to 10-fold. The new set of S values can be applied prospectively or retrospectively to the calculation of radiation doses in adults internally exposed to (131)I, including nuclear medicine patients treated for thyroid cancer or hyperthyroidism.

  9. Monte Carlo simulations for external neutron dosimetry based on the visible Chinese human phantom.

    PubMed

    Zhang, Guozhi; Liu, Qian; Luo, Qingming

    2007-12-21

    A group of Monte Carlo simulations has been performed for external neutron dosimetry calculation based on a whole-body anatomical model, the visible Chinese human (VCH) phantom, which was newly developed from high-resolution cryosectional color photographic images of a healthy Chinese adult male cadaver. Physical characteristics of the VCH computational phantom that consists of 230 x 120 x 892 voxels corresponding to an element volume of 2 x 2 x 2 mm(3) are evaluated through comparison against a variety of other anthropomorphic models. Organ-absorbed doses and the effective doses for monoenergic neutron beams ranging from 10(-9) MeV to 10 GeV under six idealized irradiation geometries (AP, PA, LLAT, RLAT, ROT and ISO) were calculated using the Monte Carlo code MCNPX2.5. Absorbed dose results for selected organs and the effective doses are presented in the form of tables. Dose results are also compared with currently available neutron data form ICRP Publication 74 and those of VIP-Man. Anatomical variations between different models, as well as their influence on dose distributions, are explored. Detailed information derived from the VCH phantom is able to lend quantitative references to the widespread application of human computational models in radiology. PMID:18065844

  10. Monte Carlo simulations for external neutron dosimetry based on the visible Chinese human phantom

    NASA Astrophysics Data System (ADS)

    Zhang, Guozhi; Liu, Qian; Luo, Qingming

    2007-12-01

    A group of Monte Carlo simulations has been performed for external neutron dosimetry calculation based on a whole-body anatomical model, the visible Chinese human (VCH) phantom, which was newly developed from high-resolution cryosectional color photographic images of a healthy Chinese adult male cadaver. Physical characteristics of the VCH computational phantom that consists of 230 × 120 × 892 voxels corresponding to an element volume of 2 × 2 × 2 mm3 are evaluated through comparison against a variety of other anthropomorphic models. Organ-absorbed doses and the effective doses for monoenergic neutron beams ranging from 10-9 MeV to 10 GeV under six idealized irradiation geometries (AP, PA, LLAT, RLAT, ROT and ISO) were calculated using the Monte Carlo code MCNPX2.5. Absorbed dose results for selected organs and the effective doses are presented in the form of tables. Dose results are also compared with currently available neutron data form ICRP Publication 74 and those of VIP-Man. Anatomical variations between different models, as well as their influence on dose distributions, are explored. Detailed information derived from the VCH phantom is able to lend quantitative references to the widespread application of human computational models in radiology.

  11. A new anthropometric phantom for calibrating in vivo measurements of stable lead in the human leg using X-ray fluorescence

    SciTech Connect

    Spitz, H.; Jenkins, M.; Lodwick, J.; Bornschein, R.

    2000-02-01

    A new anthropometric phantom has been developed for calibrating in vivo measurements of stable lead deposited in bone using x-ray fluorescence. The phantom reproduces the shape of the mid shaft of the adult human leg and is fabricated using polyurethanes and calcium carbonate to produce materials that exhibit the same density, energy transmission, and calcium content as cortical bone, bone marrow, and muscle. The phantom includes a removable tibia fabricated using simulants for cortical bone and bone marrow to which a precise amount of stable lead has been added to cortical bone. The formulations used in fabricating the new anthropometric phantom are much more uniform in density and composition than the conventional phantom made from Plexiglas cylinders filled with plaster-of-Paris. The energy spectrum from an x-ray fluorescence measurement of the phantom using a {sup 109}Cd source is indistinguishable from an in vivo x-ray fluorescence measurement of the human leg, demonstrating that the materials used in the phantom exhibit the same radiological properties as human tissue. Likewise, results from x-ray fluorescence measurements of the phantom exhibit the same positional dependency as the human leg and vary by approximately 36% when, for example, the phantom containing 54 ppm of stable lead in the tibia was rotated by only 15 degrees. The detection limit for a 30 min {sup 109}Cd K shell x-ray fluorescence in vivo measurement is approximately 20 ppm determined from a background measurement using the new phantom containing no added lead in the muscle, bone, or bone marrow. The new anthropometric phantom significantly improves in vivo x-ray fluorescence calibration measurements by (1) faithfully reproducing the anatomy of the human leg, (2) having components that exhibit radiological properties similar to that of human tissue, and (3) providing a realistic calibration standard that can be used for in vivo x-ray fluorescence intercomparison measurements.

  12. Comparison of organ dose and dose equivalent for human phantoms of CAM vs. MAX

    NASA Astrophysics Data System (ADS)

    Kim, Myung-Hee Y.; Qualls, Garry D.; Slaba, Tony C.; Cucinotta, Francis A.

    2010-04-01

    For the evaluation of organ dose and dose equivalent of astronauts on space shuttle and the International Space Station (ISS) missions, the CAMERA models of CAM (Computerized Anatomical Male) and CAF (Computerized Anatomical Female) of human tissue shielding have been implemented and used in radiation transport model calculations at NASA. One of new human geometry models to meet the “reference person” of International Commission on Radiological Protection (ICRP) is based on detailed Voxel (volumetric and pixel) phantom models denoted for male and female as MAX (Male Adult voXel) and FAX (Female Adult voXel), respectively. We compared the CAM model predictions of organ doses to those of MAX model, since the MAX model represents the male adult body with much higher fidelity than the CAM model currently used at NASA. Directional body-shielding mass was evaluated for over 1500 target points of MAX for specified organs considered to be sensitive to the induction of stochastic effects. Radiation exposures to solar particle event (SPE), trapped protons, and galactic cosmic ray (GCR) were assessed at the specific sites in the MAX phantom by coupling space radiation transport models with the relevant body-shielding mass. The development of multiple-point body-shielding distributions at each organ made it possible to estimate the mean and variance of organ doses at the specific organ. For the estimate of doses to the blood forming organs (BFOs), data on active marrow distributions in adult were used to weight the bone marrow sites over the human body. The discrete number of target points of MAX organs resulted in a reduced organ dose and dose equivalent compared to the results of CAM organs especially for SPE, and should be further investigated. Differences of effective doses between the two approaches were found to be small (<5%) for GCR.

  13. Organ dose calculations by Monte Carlo modeling of the updated VCH adult male phantom against idealized external proton exposure

    NASA Astrophysics Data System (ADS)

    Zhang, Guozhi; Liu, Qian; Zeng, Shaoqun; Luo, Qingming

    2008-07-01

    The voxel-based visible Chinese human (VCH) adult male phantom has offered a high-quality test bed for realistic Monte Carlo modeling in radiological dosimetry simulations. The phantom has been updated in recent effort by adding newly segmented organs, revising walled and smaller structures as well as recalibrating skeletal marrow distributions. The organ absorbed dose against external proton exposure was calculated at a voxel resolution of 2 × 2 × 2 mm3 using the MCNPX code for incident energies from 20 MeV to 10 GeV and for six idealized irradiation geometries: anterior-posterior (AP), posterior-anterior (PA), left-lateral (LLAT), right-lateral (RLAT), rotational (ROT) and isotropic (ISO), respectively. The effective dose on the VCH phantom was derived in compliance with the evaluation scheme for the reference male proposed in the 2007 recommendations of the International Commission on Radiological Protection (ICRP). Algorithm transitions from the revised radiation and tissue weighting factors are accountable for approximately 90% and 10% of effective dose discrepancies in proton dosimetry, respectively. Results are tabulated in terms of fluence-to-dose conversion coefficients for practical use and are compared with data from other models available in the literature. Anatomical variations between various computational phantoms lead to dose discrepancies ranging from a negligible level to 100% or more at proton energies below 200 MeV, corresponding to the spatial geometric locations of individual organs within the body. Doses show better agreement at higher energies and the deviations are mostly within 20%, to which the organ volume and mass differences should be of primary responsibility. The impact of body size on dose distributions was assessed by dosimetry of a scaled-up VCH phantom that was resized in accordance with the height and total mass of the ICRP reference man. The organ dose decreases with the directionally uniform enlargement of voxels. Potential

  14. Organ doses from environmental exposures calculated using voxel phantoms of adults and children

    NASA Astrophysics Data System (ADS)

    Petoussi-Henss, Nina; Schlattl, H.; Zankl, M.; Endo, A.; Saito, K.

    2012-09-01

    This paper presents effective and organ dose conversion coefficients for members of the public due to environmental external exposures, calculated using the ICRP adult male and female reference computational phantoms as well as voxel phantoms of a baby, two children and four adult individual phantoms--one male and three female, one of them pregnant. Dose conversion coefficients are given for source geometries representing environmental radiation exposures, i.e. whole body irradiations from a volume source in air, representing a radioactive cloud, a plane source in the ground at a depth of 0.5 g cm-2, representing ground contamination by radioactive fall-out, and uniformly distributed natural sources in the ground. The organ dose conversion coefficients were calculated employing the Monte Carlo code EGSnrc simulating the photon transport in the voxel phantoms, and are given as effective and equivalent doses normalized to air kerma free-in-air at height 1 m above the ground in Sv Gy-1. The findings showed that, in general, the smaller the body mass of the phantom, the higher the dose. The difference in effective dose between an adult and an infant is 80-90% at 50 keV and less than 40% above 100 keV. Furthermore, dose equivalent rates for photon exposures of several radionuclides for the above environmental exposures were calculated with the most recent nuclear decay data. Data are shown for effective dose, thyroid, colon and red bone marrow. The results are expected to facilitate regulation of exposure to radiation, relating activities of radionuclides distributed in air and ground to dose of the public due to external radiation as well as the investigation of the radiological effects of major radiation accidents such as the recent one in Fukushima and the decision making of several committees.

  15. Development of the two Korean adult tomographic computational phantoms for organ dosimetry

    SciTech Connect

    Lee, Choonsik; Lee, Choonik; Park, Sang-Hyun; Lee, Jai-Ki

    2006-02-15

    Following the previously developed Korean tomographic phantom, KORMAN, two additional whole-body tomographic phantoms of Korean adult males were developed from magnetic resonance (MR) and computed tomography (CT) images, respectively. Two healthy male volunteers, whose body dimensions were fairly representative of the average Korean adult male, were recruited and scanned for phantom development. Contiguous whole body MR images were obtained from one subject exclusive of the arms, while whole-body CT images were acquired from the second individual. A total of 29 organs and tissues and 19 skeletal sites were segmented via image manipulation techniques such as gray-level thresholding, region growing, and manual drawing, in which each of segmented image slice was subsequently reviewed by an experienced radiologist for anatomical accuracy. The resulting phantoms, the MR-based KTMAN-1 (Korean Typical MAN-1) and the CT-based KTMAN-2 (Korean Typical MAN-2), consist of 300x150x344 voxels with a voxel resolution of 2x2x5 mm{sup 3} for both phantoms. Masses of segmented organs and tissues were calculated as the product of a nominal reference density, the prevoxel volume, and the cumulative number of voxels defining each organs or tissue. These organs masses were then compared with those of both the Asian and the ICRP reference adult male. Organ masses within both KTMAN-1 and KTMAN-2 showed differences within 40% of Asian and ICRP reference values, with the exception of the skin, gall bladder, and pancreas which displayed larger differences. The resulting three-dimensional binary file was ported to the Monte Carlo code MCNPX2.4 to calculate organ doses following external irradiation for illustrative purposes. Colon, lung, liver, and stomach absorbed doses, as well as the effective dose, for idealized photon irradiation geometries (anterior-posterior and right lateral) were determined, and then compared with data from two other tomographic phantoms (Asian and Caucasian), and

  16. Input files with ORNL—mathematical phantoms of the human body for MCNP-4B

    NASA Astrophysics Data System (ADS)

    Krstić, D.; Nikezić, D.

    2007-01-01

    Protection against ionizing radiation requires information on the absorbed doses in organs of the human body. Implantation of many dosimeters in the human body is undesirable (or impossible), so the doses in organs are not measurable and some kind of dose calculation has to be applied. Calculation of doses in organs requests: (a) an exact description of the geometry of organs, (b) the chemical constitution of tissues, and (c) appropriate computer programs. The first two items, (a) and (b), make a so-called "phantom". In another words, the "phantom of a human body" is a mathematical representation of the human body including all other relevant information. All organs are represented with geometrical bodies (like cylinders, ellipsoids, tori, cones etc.), which are described with suitable mathematical equations. A corresponding chemical constitution for various types of organ tissues is also defined. MCNP-4B ( Monte Carlo N- Particle) is often used as transport code. Users of this software prepare an "input file" providing all necessary information for program execution. This information includes: (a) source definition—type of ionizing radiation, energy spectrum, and geometry of the source; (b) target definition—material constitution, geometry, location in respect to the source etc.; (c) characterization of absorbing media between the source and target; (d) output tally, etc. This paper presents input files with "human phantoms" for the MCNP-4B code. The input files with "phantoms" were prepared based on publications issued by the Oak Ridge National Laboratory (ORNL). Seven input files relating to different age groups (newborn, 1, 5, 10, 15 years, as well as, male and female adults) are presented here. A test example and comparison with other data found in literature are also given. Program summaryTitle of program: INPUT FILES, AMALE, AFEMALE, AGE15, AGE10, AGE5, AGE01, NEWB Catalogue identifier:ADYF_v1_0 Program summary URL

  17. Posture-specific phantoms representing female and male adults in Monte Carlo-based simulations for radiological protection

    NASA Astrophysics Data System (ADS)

    Cassola, V. F.; Kramer, R.; Brayner, C.; Khoury, H. J.

    2010-08-01

    Does the posture of a patient have an effect on the organ and tissue absorbed doses caused by x-ray examinations? This study aims to find the answer to this question, based on Monte Carlo (MC) simulations of commonly performed x-ray examinations using adult phantoms modelled to represent humans in standing as well as in the supine posture. The recently published FASH (female adult mesh) and MASH (male adult mesh) phantoms have the standing posture. In a first step, both phantoms were updated with respect to their anatomy: glandular tissue was separated from adipose tissue in the breasts, visceral fat was separated from subcutaneous fat, cartilage was segmented in ears, nose and around the thyroid, and the mass of the right lung is now 15% greater than the left lung. The updated versions are called FASH2_sta and MASH2_sta (sta = standing). Taking into account the gravitational effects on organ position and fat distribution, supine versions of the FASH2 and the MASH2 phantoms have been developed in this study and called FASH2_sup and MASH2_sup. MC simulations of external whole-body exposure to monoenergetic photons and partial-body exposure to x-rays have been made with the standing and supine FASH2 and MASH2 phantoms. For external whole-body exposure for AP and PA projection with photon energies above 30 keV, the effective dose did not change by more than 5% when the posture changed from standing to supine or vice versa. Apart from that, the supine posture is quite rare in occupational radiation protection from whole-body exposure. However, in the x-ray diagnosis supine posture is frequently used for patients submitted to examinations. Changes of organ absorbed doses up to 60% were found for simulations of chest and abdomen radiographs if the posture changed from standing to supine or vice versa. A further increase of differences between posture-specific organ and tissue absorbed doses with increasing whole-body mass is to be expected.

  18. Monte Carlo estimation of radiation dose in organs of female and male adult phantoms due to FDG-F18 absorbed in the lungs

    NASA Astrophysics Data System (ADS)

    Belinato, Walmir; Santos, William S.; Silva, Rogério M. V.; Souza, Divanizia N.

    2014-03-01

    The determination of dose conversion factors (S values) for the radionuclide fluorodeoxyglucose (18F-FDG) absorbed in the lungs during a positron emission tomography (PET) procedure was calculated using the Monte Carlo method (MCNPX version 2.7.0). For the obtained dose conversion factors of interest, it was considered a uniform absorption of radiopharmaceutical by the lung of a healthy adult human. The spectrum of fluorine was introduced in the input data file for the simulation. The simulation took place in two adult phantoms of both sexes, based on polygon mesh surfaces called FASH and MASH with anatomy and posture according to ICRP 89. The S values for the 22 internal organs/tissues, chosen from ICRP No. 110, for the FASH and MASH phantoms were compared with the results obtained from a MIRD V phantoms called ADAM and EVA used by the Committee on Medical Internal Radiation Dose (MIRD). We observed variation of more than 100% in S values due to structural anatomical differences in the internal organs of the MASH and FASH phantoms compared to the mathematical phantom.

  19. Dose distribution in a human phantom onboard aircraft

    NASA Astrophysics Data System (ADS)

    Berger, T.; Meier, M.; Reitz, G.; Schridde, M.

    The exposure of aircrew personnel to cosmic radiation has been considered as occupational exposure in the European Union since the European Council Directive 96 29 EURATOM became effective on May 13 1996 In Germany the corresponding safety standards for aircrew which include dose assessment among other things are regulated by the German Radiation Protection Ordinance which implemented the European law and was amended in 2001 The radiation exposure of most German aircrew is calculated by the DLR Institute of Aerospace Medicine in Cologne applying the calculation program EPCARD in the framework of the aircrew dose determination system CALVADOS underline CAL culated and underline V erified underline A viation underline DOS imetry Beside the operational dose calculations DLR performs measuring flights applying active e g TEPC DOSTEL etc and passive TLDs bubble detectors radiation detectors to verify the calculation codes Within these activities the project BODO underline BO dy underline DO simetry comprised a long term exposure of a RANDO copyright anthropomorphic phantom to measure for the first time the skin and the depth dose distribution inside a simulated human torso at aviation altitudes The torso was flown for three months from mid of July to mid of October 2004 onboard a Lufthansa Cargo aircraft This torso made up of 27 polyurethane slices with different densities -- simulating tissue and organs -- was equipped with passive thermoluminescence detectors TLDs of different types namely TLD 600 6 LiF Mg

  20. Computational lymphatic node models in pediatric and adult hybrid phantoms for radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Lee, Choonsik; Lamart, Stephanie; Moroz, Brian E.

    2013-03-01

    We developed models of lymphatic nodes for six pediatric and two adult hybrid computational phantoms to calculate the lymphatic node dose estimates from external and internal radiation exposures. We derived the number of lymphatic nodes from the recommendations in International Commission on Radiological Protection (ICRP) Publications 23 and 89 at 16 cluster locations for the lymphatic nodes: extrathoracic, cervical, thoracic (upper and lower), breast (left and right), mesentery (left and right), axillary (left and right), cubital (left and right), inguinal (left and right) and popliteal (left and right), for different ages (newborn, 1-, 5-, 10-, 15-year-old and adult). We modeled each lymphatic node within the voxel format of the hybrid phantoms by assuming that all nodes have identical size derived from published data except narrow cluster sites. The lymph nodes were generated by the following algorithm: (1) selection of the lymph node site among the 16 cluster sites; (2) random sampling of the location of the lymph node within a spherical space centered at the chosen cluster site; (3) creation of the sphere or ovoid of tissue representing the node based on lymphatic node characteristics defined in ICRP Publications 23 and 89. We created lymph nodes until the pre-defined number of lymphatic nodes at the selected cluster site was reached. This algorithm was applied to pediatric (newborn, 1-, 5-and 10-year-old male, and 15-year-old males) and adult male and female ICRP-compliant hybrid phantoms after voxelization. To assess the performance of our models for internal dosimetry, we calculated dose conversion coefficients, called S values, for selected organs and tissues with Iodine-131 distributed in six lymphatic node cluster sites using MCNPX2.6, a well validated Monte Carlo radiation transport code. Our analysis of the calculations indicates that the S values were significantly affected by the location of the lymph node clusters and that the values increased for

  1. Computational lymphatic node models in pediatric and adult hybrid phantoms for radiation dosimetry.

    PubMed

    Lee, Choonsik; Lamart, Stephanie; Moroz, Brian E

    2013-03-01

    We developed models of lymphatic nodes for six pediatric and two adult hybrid computational phantoms to calculate the lymphatic node dose estimates from external and internal radiation exposures. We derived the number of lymphatic nodes from the recommendations in International Commission on Radiological Protection (ICRP) Publications 23 and 89 at 16 cluster locations for the lymphatic nodes: extrathoracic, cervical, thoracic (upper and lower), breast (left and right), mesentery (left and right), axillary (left and right), cubital (left and right), inguinal (left and right) and popliteal (left and right), for different ages (newborn, 1-, 5-, 10-, 15-year-old and adult). We modeled each lymphatic node within the voxel format of the hybrid phantoms by assuming that all nodes have identical size derived from published data except narrow cluster sites. The lymph nodes were generated by the following algorithm: (1) selection of the lymph node site among the 16 cluster sites; (2) random sampling of the location of the lymph node within a spherical space centered at the chosen cluster site; (3) creation of the sphere or ovoid of tissue representing the node based on lymphatic node characteristics defined in ICRP Publications 23 and 89. We created lymph nodes until the pre-defined number of lymphatic nodes at the selected cluster site was reached. This algorithm was applied to pediatric (newborn, 1-, 5-and 10-year-old male, and 15-year-old males) and adult male and female ICRP-compliant hybrid phantoms after voxelization. To assess the performance of our models for internal dosimetry, we calculated dose conversion coefficients, called S values, for selected organs and tissues with Iodine-131 distributed in six lymphatic node cluster sites using MCNPX2.6, a well validated Monte Carlo radiation transport code. Our analysis of the calculations indicates that the S values were significantly affected by the location of the lymph node clusters and that the values increased for

  2. Comparison of internal doses calculated using the specific absorbed fractions of the average adult Japanese male phantom with those of the reference computational phantom-adult male of ICRP publication 110

    NASA Astrophysics Data System (ADS)

    Manabe, Kentaro; Sato, Kaoru; Endo, Akira

    2014-03-01

    In order to study the effects of body sizes and masses of organs and tissues on internal dose assessment, the values corresponding to effective dose coefficients for intakes of radionuclides were calculated using the specific absorbed fractions (SAFs) of two phantoms: the average adult Japanese male phantom (JM-103) and the reference computational phantom-adult male (RCP-AM) of the International Commission on Radiological Protection. SAFs were evaluated using the phantoms and Monte Carlo radiation transport code MCNPX or were taken from published data. As a result of a comparison for 2894 cases of 923 radionuclides, the maximum discrepancy in the effective dose coefficients between the JM-103 and RCP-AM was about 40%. However, the discrepancies were smaller than 10% in 97% of all cases.

  3. Directly detected 55Mn MRI: Application to phantoms for human hyperpolarized 13C MRI development

    PubMed Central

    von Morze, Cornelius; Carvajal, Lucas; Reed, Galen D.; Swisher, Christine Leon; Tropp, James; Vigneron, Daniel B.

    2014-01-01

    In this work we demonstrate for the first time directly detected manganese-55 (55Mn) MRI using a clinical 3T MRI scanner designed for human hyperpolarized 13C clinical studies with no additional hardware modifications. Due to the similar frequency of the 55Mn and 13C resonances, the use of aqueous permanganate for large, signal-dense, and cost-effective “13C” MRI phantoms was investigated, addressing the clear need for new phantoms for these studies. Due to 100% natural abundance, higher intrinsic sensitivity, and favorable relaxation properties, 55Mn MRI of aqueous permanganate demonstrates dramatically increased sensitivity over typical 13C phantom MRI, at greatly reduced cost as compared with large 13C-enriched phantoms. A large sensitivity advantage (22-fold) was demonstrated. A cylindrical phantom (d= 8 cm) containing concentrated aqueous sodium permanganate (2.7M) was scanned rapidly by 55Mn MRI in a human head coil tuned for 13C, using a balanced SSFP acquisition. The requisite penetration of RF magnetic fields into concentrated permanganate was investigated by experiments and high frequency electromagnetic simulations, and found to be sufficient for 55Mn MRI with reasonably sized phantoms. A sub-second slice-selective acquisition yielded mean image SNR of ~60 at 0.5cm3 spatial resolution, distributed with minimum central signal ~40% of the maximum edge signal. We anticipate that permanganate phantoms will be very useful for testing HP 13C coils and methods designed for human studies. PMID:25179135

  4. Monte Carlo simulations of adult and pediatric computed tomography exams: Validation studies of organ doses with physical phantoms

    SciTech Connect

    Long, Daniel J.; Lee, Choonsik; Tien, Christopher; Fisher, Ryan; Hoerner, Matthew R.; Hintenlang, David; Bolch, Wesley E.

    2013-01-15

    Purpose: To validate the accuracy of a Monte Carlo source model of the Siemens SOMATOM Sensation 16 CT scanner using organ doses measured in physical anthropomorphic phantoms. Methods: The x-ray output of the Siemens SOMATOM Sensation 16 multidetector CT scanner was simulated within the Monte Carlo radiation transport code, MCNPX version 2.6. The resulting source model was able to perform various simulated axial and helical computed tomographic (CT) scans of varying scan parameters, including beam energy, filtration, pitch, and beam collimation. Two custom-built anthropomorphic phantoms were used to take dose measurements on the CT scanner: an adult male and a 9-month-old. The adult male is a physical replica of University of Florida reference adult male hybrid computational phantom, while the 9-month-old is a replica of University of Florida Series B 9-month-old voxel computational phantom. Each phantom underwent a series of axial and helical CT scans, during which organ doses were measured using fiber-optic coupled plastic scintillator dosimeters developed at University of Florida. The physical setup was reproduced and simulated in MCNPX using the CT source model and the computational phantoms upon which the anthropomorphic phantoms were constructed. Average organ doses were then calculated based upon these MCNPX results. Results: For all CT scans, good agreement was seen between measured and simulated organ doses. For the adult male, the percent differences were within 16% for axial scans, and within 18% for helical scans. For the 9-month-old, the percent differences were all within 15% for both the axial and helical scans. These results are comparable to previously published validation studies using GE scanners and commercially available anthropomorphic phantoms. Conclusions: Overall results of this study show that the Monte Carlo source model can be used to accurately and reliably calculate organ doses for patients undergoing a variety of axial or helical CT

  5. A heterogeneous human tissue mimicking phantom for RF heating and MRI thermal monitoring verification

    NASA Astrophysics Data System (ADS)

    Yuan, Yu; Wyatt, Cory; Maccarini, Paolo; Stauffer, Paul; Craciunescu, Oana; MacFall, James; Dewhirst, Mark; Das, Shiva K.

    2012-04-01

    This paper describes a heterogeneous phantom that mimics a human thigh with a deep-seated tumor, for the purpose of studying the performance of radiofrequency (RF) heating equipment and non-invasive temperature monitoring with magnetic resonance imaging (MRI). The heterogeneous cylindrical phantom was constructed with an outer fat layer surrounding an inner core of phantom material mimicking muscle, tumor and marrow-filled bone. The component materials were formulated to have dielectric and thermal properties similar to human tissues. The dielectric properties of the tissue mimicking phantom materials were measured with a microwave vector network analyzer and impedance probe over the frequency range of 80-500 MHz and at temperatures of 24, 37 and 45 °C. The specific heat values of the component materials were measured using a differential scanning calorimeter over the temperature range of 15-55 °C. The thermal conductivity value was obtained from fitting the curves obtained from one-dimensional heat transfer measurement. The phantom was used to verify the operation of a cylindrical four-antenna annular phased array extremity applicator (140 MHz) by examining the proton resonance frequency shift (PRFS) thermal imaging patterns for various magnitude/phase settings (including settings to focus heating in tumors). For muscle and tumor materials, MRI was also used to measure T1/T2* values (1.5 T) and to obtain the slope of the PRFS phase change versus temperature change curve. The dielectric and thermal properties of the phantom materials were in close agreement to well-accepted published results for human tissues. The phantom was able to successfully demonstrate satisfactory operation of the tested heating equipment. The MRI-measured thermal distributions matched the expected patterns for various magnitude/phase settings of the applicator, allowing the phantom to be used as a quality assurance tool. Importantly, the material formulations for the various tissue types

  6. A Monte Carlo approach to assessing 147Pm in the liver of the adult phantom.

    PubMed

    Bhati, S

    1993-06-01

    A low-background phoswich detector is used to detect small amounts of 147Pm--a pure beta-emitting nuclide--present in the liver of an occupational worker. The assessment was based on the measurement of bremsstrahlung radiation produced by the beta particles in the tissue. Computer programs based on Monte Carlo techniques for photon transport have been developed to calculate the response of an external phoswich detector to 1) a 147Pm point source embedded in tissue-equivalent slabs of various thicknesses; and 2) various source distributions of 147Pm in the liver of an adult phantom. The goal is to theoretically calibrate the phoswich detector for each source distribution and to study the variation of maxima of the spectra with the depth of the source in the adult phantom liver and tissue-equivalent slabs. The initial bremsstrahlung photon distribution of 147Pm in water has been computed using Wyard's and Pratt's methods. These calculations have been compared with experimental measurements using Perspex acrylic sheet slabs. Good agreements have been noted when the initial bremsstrahlung spectrum is obtained by using Wyard's method. These results find applications in monitoring the liver burdens in occupational workers handling 147Pm-based radioluminous paints.

  7. Diffusion Capillary Phantom vs. Human Data: Outcomes for Reconstruction Methods Depend on Evaluation Medium

    PubMed Central

    Lichenstein, Sarah D.; Bishop, James H.; Verstynen, Timothy D.; Yeh, Fang-Cheng

    2016-01-01

    Purpose: Diffusion MRI provides a non-invasive way of estimating structural connectivity in the brain. Many studies have used diffusion phantoms as benchmarks to assess the performance of different tractography reconstruction algorithms and assumed that the results can be applied to in vivo studies. Here we examined whether quality metrics derived from a common, publically available, diffusion phantom can reliably predict tractography performance in human white matter tissue. Materials and Methods: We compared estimates of fiber length and fiber crossing among a simple tensor model (diffusion tensor imaging), a more complicated model (ball-and-sticks) and model-free (diffusion spectrum imaging, generalized q-sampling imaging) reconstruction methods using a capillary phantom and in vivo human data (N = 14). Results: Our analysis showed that evaluation outcomes differ depending on whether they were obtained from phantom or human data. Specifically, the diffusion phantom favored a more complicated model over a simple tensor model or model-free methods for resolving crossing fibers. On the other hand, the human studies showed the opposite pattern of results, with the model-free methods being more advantageous than model-based methods or simple tensor models. This performance difference was consistent across several metrics, including estimating fiber length and resolving fiber crossings in established white matter pathways. Conclusions: These findings indicate that the construction of current capillary diffusion phantoms tends to favor complicated reconstruction models over a simple tensor model or model-free methods, whereas the in vivo data tends to produce opposite results. This brings into question the previous phantom-based evaluation approaches and suggests that a more realistic phantom or simulation is necessary to accurately predict the relative performance of different tractography reconstruction methods.

  8. Diffusion Capillary Phantom vs. Human Data: Outcomes for Reconstruction Methods Depend on Evaluation Medium

    PubMed Central

    Lichenstein, Sarah D.; Bishop, James H.; Verstynen, Timothy D.; Yeh, Fang-Cheng

    2016-01-01

    Purpose: Diffusion MRI provides a non-invasive way of estimating structural connectivity in the brain. Many studies have used diffusion phantoms as benchmarks to assess the performance of different tractography reconstruction algorithms and assumed that the results can be applied to in vivo studies. Here we examined whether quality metrics derived from a common, publically available, diffusion phantom can reliably predict tractography performance in human white matter tissue. Materials and Methods: We compared estimates of fiber length and fiber crossing among a simple tensor model (diffusion tensor imaging), a more complicated model (ball-and-sticks) and model-free (diffusion spectrum imaging, generalized q-sampling imaging) reconstruction methods using a capillary phantom and in vivo human data (N = 14). Results: Our analysis showed that evaluation outcomes differ depending on whether they were obtained from phantom or human data. Specifically, the diffusion phantom favored a more complicated model over a simple tensor model or model-free methods for resolving crossing fibers. On the other hand, the human studies showed the opposite pattern of results, with the model-free methods being more advantageous than model-based methods or simple tensor models. This performance difference was consistent across several metrics, including estimating fiber length and resolving fiber crossings in established white matter pathways. Conclusions: These findings indicate that the construction of current capillary diffusion phantoms tends to favor complicated reconstruction models over a simple tensor model or model-free methods, whereas the in vivo data tends to produce opposite results. This brings into question the previous phantom-based evaluation approaches and suggests that a more realistic phantom or simulation is necessary to accurately predict the relative performance of different tractography reconstruction methods. PMID:27656122

  9. Assessment of neutron fluence to organ dose conversion coefficients in the ORNL analytical adult phantom.

    PubMed

    Miri Hakimabad, H; Rafat Motavalli, L; Karimi Shahri, K

    2009-03-01

    Neutron fluence to absorbed dose conversion coefficients have been evaluated for the analytical ORNL modified adult phantom in 21 body organs using MCNP4C Monte Carlo code. The calculation used 20 monodirectional monoenergetic neutron beams in the energy range 10(-9)-20 MeV, under four irradiation conditions: anterior-posterior (AP), posterior-anterior (PA), left-lateral (LLAT) and right-lateral (RLAT). Then the conversion coefficients are compared with the data reported in ICRP publication 74 for mathematical MIRD type phantoms and by Bozkurt et al for the VIPMAN voxel model. Although the ORNL results show fewer differences with the ICRP results than the Bozkurt et al data, one can deduce neither complete agreement nor disparity between this study and other data sets. This comparison shows that in some cases any differences in applied Monte Carlo codes or simulated body models could significantly change the organ dose conversion factors. This sensitivity should be considered for radiological protection programmes. For certain organs, the results of two models with major differences can be in a satisfactory agreement because of the similarity in those organ models. PMID:19225185

  10. [The model of geometrical human body phantom for calculating tissue doses in the service module of the International Space Station].

    PubMed

    Bondarenko, V A; Mitrikas, V G

    2007-01-01

    The model of a geometrical human body phantom developed for calculating the shielding functions of representative points of the body organs and systems is similar to the anthropomorphic phantom. This form of phantom can be integrated with the shielding model of the ISS Russian orbital segment to make analysis of radiation loading of crewmembers in different compartments of the vehicle. Calculation of doses absorbed by the body systems in terms of the representative points makes it clear that doses essentially depend on the phantom spatial orientation (eye direction). It also enables the absorbed dose evaluation from the shielding functions as the mean of the representative points and phantom orientation.

  11. The influence of patient size on dose conversion coefficients: a hybrid phantom study for adult cardiac catheterization

    NASA Astrophysics Data System (ADS)

    Johnson, Perry; Lee, Choonsik; Johnson, Kevin; Siragusa, Daniel; Bolch, Wesley E.

    2009-06-01

    In this study, the influence of patient size on organ and effective dose conversion coefficients (DCCs) was investigated for a representative interventional fluoroscopic procedure—cardiac catheterization. The study was performed using hybrid phantoms representing an underweight, average and overweight American adult male. Reference body sizes were determined using the NHANES III database and parameterized based on standing height and total body mass. Organ and effective dose conversion coefficients were calculated for anterior-posterior, posterior-anterior, left anterior oblique and right anterior oblique projections using the Monte Carlo code MCNPX 2.5.0 with the metric dose area product being used as the normalization factor. Results show body size to have a clear influence on DCCs which increased noticeably when body size decreased. It was also shown that if patient size is neglected when choosing a DCC, the organ and effective dose will be underestimated to an underweight patient and will be overestimated to an underweight patient, with errors as large as 113% for certain projections. Results were further compared with those published for a KTMAN-2 Korean patient-specific tomographic phantom. The published DCCs aligned best with the hybrid phantom which most closely matched in overall body size. These results highlighted the need for and the advantages of phantom-patient matching, and it is recommended that hybrid phantoms be used to create a more diverse library of patient-dependent anthropomorphic phantoms for medical dose reconstruction.

  12. Food source provisioning and susceptibility of immature and adult Tribolium castaneum on concrete partially treated with chlorfenapyr (Phantom®)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A series of experiments were conducted in which adults, pupae, and 4-week-old larvae of Tribolium castaneum (Herbst), the red flour beetle, were exposed separately on concrete arenas partially treated (14.4 % of the total area) with the insecticide chlorfenapyr (Phantom®) at 1.1 g active ingredient/...

  13. Analytical reconstructions of intensity modulated x-ray phase-contrast imaging of human scale phantoms

    PubMed Central

    Włodarczyk, Bartłomiej; Pietrzak, Jakub

    2015-01-01

    This paper presents analytical approach to modeling of a full planar and volumetric acquisition system with image reconstructions originated from partial illumination x-ray phase-contrast imaging at a human scale using graphics processor units. The model is based on x-ray tracing and wave optics methods to develop a numerical framework for predicting the performance of a preclinical phase-contrast imaging system of a human-scaled phantom. In this study, experimental images of simple numerical phantoms and high resolution anthropomorphic phantoms of head and thorax based on non-uniform rational b-spline shapes (NURBS) prove the correctness of the model. Presented results can be used to simulate the performance of partial illumination x-ray phase-contrast imaging system on various preclinical applications. PMID:26600991

  14. Demonstration of motor imagery movement and phantom movement-related neuronal activity in human thalamus.

    PubMed

    Anderson, William S; Weiss, Nirit; Lawson, Herman Christopher; Ohara, Shinji; Rowland, Lance; Lenz, Frederick A

    2011-01-26

    Functional imaging studies show that motor imagery activates multiple structures in the human forebrain. We now show that phantom movements in an amputee and imagined movements in intact individuals elicit responses from neurons in several human thalamic nuclei. These include the somatic sensory nucleus receiving input from the periphery (ventral caudal), and the motor nuclei receiving input from the cerebellum [ventral intermediate (Vim)] and the basal ganglia [ventral oral posterior (Vop)]. Seven neurons in the amputee showed phantom movement-related activity (three Vim, two Vop, and two ventral caudal). In addition, seven neurons in a group of three controls showed motor imagery-related activity (four Vim and three Vop). These studies were performed during single neuron recording sessions in patients undergoing therapeutic treatment of phantom pain, tremor, and chronic pain conditions by thalamic stimulation. The activity of neurons in these sensory and motor nuclei, respectively, may encode the expected sensory consequences and the dynamics of planned movements.

  15. A heterogeneous human tissue mimicking phantom for RF heating and MRI thermal monitoring verification

    PubMed Central

    Yuan, Yu; Wyatt, Cory; Maccarini, Paolo; Stauffer, Paul; Craciunescu, Oana; MacFall, James; Dewhirst, Mark; Das, Shiva K.

    2013-01-01

    This paper describes a heterogeneous phantom that mimics a human thigh with a deep seated tumor, for the purpose of studying the performance of radiofrequency (RF) heating equipment and non-invasive temperature monitoring with magnetic resonance imaging (MRI). The heterogeneous cylindrical phantom was constructed with an outer fat layer surrounding an inner core of phantom material mimicking muscle, tumor and marrow-filled bone. The component materials were formulated to have dielectric and thermal properties similar to human tissues. The dielectric properties of the tissue-mimicking phantom materials were measured with a microwave vector network analyzer and impedance probe over the frequency range of 80 – 500 MHz and at temperatures of 24°C, 37°C, and 45°C. The specific heat values of the component materials were measured using a differential scanning calorimeter over the temperature range of 15 – 55°C. The thermal conductivity value was obtained from fitting the curves obtained from one-dimensional heat transfer measurement. The phantom was used to verify the operation of a cylindrical 4-antenna annular phased array extremity applicator (140 MHz), by examining the proton resonance frequency shift (PRFS) thermal imaging patterns for various magnitude/phase settings (including settings to focus heating in tumor). For muscle and tumor materials, MR imaging was also used to measure T1/T2* values (1.5 Tesla) and to obtain the slope of the PRFS phase change vs. temperature change curve. The dielectric and thermal properties of the phantom materials were in close agreement to well-accepted published results for human tissues. The phantom was able to successfully demonstrate satisfactory operation of the tested heating equipment. The MRI-measured thermal distributions matched the expected patterns for various magnitude/phase settings of the applicator, allowing the phantom to be used as a quality assurance tool. Importantly, the material formulations for the

  16. Computational assessment of mammography accreditation phantom images and correlation with human observer analysis

    NASA Astrophysics Data System (ADS)

    Barufaldi, Bruno; Lau, Kristen C.; Schiabel, Homero; Maidment, D. A.

    2015-03-01

    Routine performance of basic test procedures and dose measurements are essential for assuring high quality of mammograms. International guidelines recommend that breast care providers ascertain that mammography systems produce a constant high quality image, using as low a radiation dose as is reasonably achievable. The main purpose of this research is to develop a framework to monitor radiation dose and image quality in a mixed breast screening and diagnostic imaging environment using an automated tracking system. This study presents a module of this framework, consisting of a computerized system to measure the image quality of the American College of Radiology mammography accreditation phantom. The methods developed combine correlation approaches, matched filters, and data mining techniques. These methods have been used to analyze radiological images of the accreditation phantom. The classification of structures of interest is based upon reports produced by four trained readers. As previously reported, human observers demonstrate great variation in their analysis due to the subjectivity of human visual inspection. The software tool was trained with three sets of 60 phantom images in order to generate decision trees using the software WEKA (Waikato Environment for Knowledge Analysis). When tested with 240 images during the classification step, the tool correctly classified 88%, 99%, and 98%, of fibers, speck groups and masses, respectively. The variation between the computer classification and human reading was comparable to the variation between human readers. This computerized system not only automates the quality control procedure in mammography, but also decreases the subjectivity in the expert evaluation of the phantom images.

  17. Overview of the ICRP/ICRU adult reference computational phantoms and dose conversion coefficients for external idealised exposures.

    PubMed

    Endo, Akira; Petoussi-Henss, Nina; Zankl, Maria; Bolch, Wesley E; Eckerman, Keith F; Hertel, Nolan E; Hunt, John G; Pelliccioni, Maurizio; Schlattl, Helmut; Menzel, Hans-Georg

    2014-10-01

    This paper reviews the ICRP Publications 110 and 116 describing the reference computational phantoms and dose conversion coefficients for external exposures. The International Commission on Radiological Protection (ICRP) in its 2007 Recommendations made several revisions to the methods of calculation of the protection quantities. In order to implement these recommendations, the DOCAL task group of the ICRP developed computational phantoms representing the reference adult male and female and then calculated a set of dose conversion coefficients for various types of idealised external exposures. This paper focuses on the dose conversion coefficients for neutrons and investigates their relationship with the conversion coefficients of the protection and operational quantities of ICRP Publication 74. Contributing factors to the differences between these sets of conversion coefficients are discussed in terms of the changes in phantoms employed and the radiation and tissue weighting factors. PMID:24285286

  18. Development of phantom for quantitative analyses of human dentin mineral density.

    PubMed

    Hayashi-Sakai, Sachiko; Kondo, Tatsuya; Kasuga, Yuto; Sakamoto, Makoto; Endo, Hideaki; Sakai, Jun

    2015-01-01

    The purpose of the present study was to develop a novel-designed phantom that could be scanned with a sample in the same image, that specialize for quantitative analyses of human dentin mineral density using the X-ray attenuation method. A further attempt was made to demonstrate the intracoronal dentin mineral density using this phantom in mandibular incisors. The phantom prepared with a 15 mm hole in the center of an acrylic resin bar having an outside diameter of 25 mm and 8 small holes (diameter, 3 mm) were made at equal intervals around the center. Liquid dipotassium hydrogen phosphate (K2HPO4) solutions were established at 0.4, 0.6, 0.8 and 1.0 g/cm3, and were arranged to these holes. The mean value of the intracoronal dentin mineral density was 1.486 ± 0.016 g/cm3 in the present study. As the results of the present study corresponded to previous reports, this new phantom was considered to be useful. This phantom enables the analysis of samples that are not readily available by conventional mechanical tests and may facilitate biomechanical investigations using X-ray images. It was suggested that this system is a simple, accurate and novel mineralization measuring system. PMID:26484556

  19. Dosimetry and verification of Co total body irradiation with human phantom and semiconductor diodes.

    PubMed

    Allahverdi, Mahmoud; Geraily, Ghazale; Esfehani, Mahbod; Sharafi, Aliakbar; Haddad, Peyman; Shirazi, Alireza

    2007-10-01

    Total Body Irradiation (TBI) is a form of radiotherapy used for patients prior to bone marrow or stem cell transplant to destroy any undetectable cancer cells. The dosimetry characteristics of a (60)Co unit for TBI were studied and a simple method for the calculation of the prescribed dose for TBI is presented. Dose homogeneity was verified in a human phantom. Dose measurements were made in water phantom (30 × 30 × 30 cm(3)), using farmer ionization chamber (0.6 cc, TM30010, PTW) and a parallel plate ionization chamber (TM23343, PTW). Point dose measurements for AP/PA irradiation were measured in a human phantom using silicon diodes (T60010L, PTW). The lung dose was measured with an ionization chamber (0.3 cc, TM31013). The validity of the proposed algorithm was checked at TBI distance using the human phantom. The accuracy of the proposed algorithm was within 3.5%. The dose delivered to the mid-lobe of the lung was 14.14 Gy and it has been reduced to 8.16 Gy by applying the proper shield. Dose homogeneity was within ±7% for all measured points. The results indicate that a good agreement between the total prescribed and calculated midplane doses can be achieved using this method. Therefore, it could be possible to use calculated data for TBI treatments.

  20. Selected organ dose conversion coefficients for external photons calculated using ICRP adult voxel phantoms and Monte Carlo code FLUKA.

    PubMed

    Patni, H K; Nadar, M Y; Akar, D K; Bhati, S; Sarkar, P K

    2011-11-01

    The adult reference male and female computational voxel phantoms recommended by ICRP are adapted into the Monte Carlo transport code FLUKA. The FLUKA code is then utilised for computation of dose conversion coefficients (DCCs) expressed in absorbed dose per air kerma free-in-air for colon, lungs, stomach wall, breast, gonads, urinary bladder, oesophagus, liver and thyroid due to a broad parallel beam of mono-energetic photons impinging in anterior-posterior and posterior-anterior directions in the energy range of 15 keV-10 MeV. The computed DCCs of colon, lungs, stomach wall and breast are found to be in good agreement with the results published in ICRP publication 110. The present work thus validates the use of FLUKA code in computation of organ DCCs for photons using ICRP adult voxel phantoms. Further, the DCCs for gonads, urinary bladder, oesophagus, liver and thyroid are evaluated and compared with results published in ICRP 74 in the above-mentioned energy range and geometries. Significant differences in DCCs are observed for breast, testis and thyroid above 1 MeV, and for most of the organs at energies below 60 keV in comparison with the results published in ICRP 74. The DCCs of female voxel phantom were found to be higher in comparison with male phantom for almost all organs in both the geometries. PMID:21147784

  1. Fast Monte Carlo simulation on a voxelized human phantom deformed to a patient

    PubMed Central

    Bueno, G.; Déniz, O.; Carrascosa, C. B.; Delgado, J. M.; Brualla, L.

    2009-01-01

    Purpose: A method for performing fast simulations of absorbed dose using a patient’s computerized tomography (CT) scan without explicitly relying on a calibration curve is presented. Methods: The method is based on geometrical deformations performed on a standard voxelized human phantom. This involves spatially transforming the human phantom to align it with the patient CT image. Since the chemical composition and density of each voxel are given in the phantom data, a calibration curve is not used in the proposed method. For this study, the Monte Carlo (MC) code PENELOPE has been used as the simulation of reference. The results obtained with PENELOPE simulations are compared to those obtained with PENFAST and with the collapsed cone convolution algorithm implemented in a commercial treatment planning system. Results: The comparisons of the absorbed doses calculated with the different algorithms on two patient CTs and the corresponding deformed phantoms show a maximum distance to agreement of 2 mm, and in general, the obtained absorbed dose distributions are compatible within the reached statistical uncertainty. The validity of the deformation method for a broad range of patients is shown using MC simulations in random density phantoms. A PENFAST simulation of a 6 MV photon beam impinging on a patient CT reaches 2% statistical uncertainty in the absorbed dose, in a 0.1 cm3 voxel along the central axis, in 10 min running on a single core of a 2.8 GHz CPU. Conclusions: The proposed method of the absorbed dose calculation in a deformed voxelized phantom allows for dosimetric studies in the geometry of a patient CT scan. This is due to the fact that the chemical composition and material density of the phantom are known. Furthermore, simulation using the phantom geometry can provide dosimetric information for each organ. The method can be used for quality assurance procedures. In relation to PENFAST, it is shown that a purely condensed-history algorithm (class I) can

  2. A second generation of physical anthropomorphic 3D breast phantoms based on human subject data

    NASA Astrophysics Data System (ADS)

    Nolte, Adam; Kiarashi, Nooshin; Samei, Ehsan; Segars, W. P.; Lo, Joseph Y.

    2014-03-01

    Previous fabrication of anthropomorphic breast phantoms has demonstrated their viability as a model for 2D (mammography) and 3D (tomosynthesis) breast imaging systems. Further development of these models will be essential for the evaluation of breast x-ray systems. There is also the potential to use them as the ground truth in virtual clinical trials. The first generation of phantoms was segmented from human subject dedicated breast computed tomography data and fabricated into physical models using highresolution 3D printing. Two variations were made. The first was a multi-material model (doublet) printed with two photopolymers to represent glandular and adipose tissues with the greatest physical contrast available, mimicking 75% and 35% glandular tissue. The second model was printed with a single 75% glandular equivalent photopolymer (singlet) to represent glandular tissue, which can be filled independently with an adipose-equivalent material such as oil. For this study, we have focused on improving the latter, the singlet phantom. First, the temporary oil filler has been replaced with a permanent adipose-equivalent urethane-based polymer. This offers more realistic contrast as compared to the multi-material approach at the expense of air bubbles and pockets that form during the filling process. Second, microcalcification clusters have been included in the singlet model via crushed eggshells, which have very similar chemical composition to calcifications in vivo. The results from these new prototypes demonstrate significant improvement over the first generation of anthropomorphic physical phantoms.

  3. Fluence-to-dose conversion coefficients based on the posture modification of Adult Male (AM) and Adult Female (AF) reference phantoms of ICRP 110

    NASA Astrophysics Data System (ADS)

    Galeano, D. C.; Santos, W. S.; Alves, M. C.; Souza, D. N.; Carvalho, A. B.

    2016-04-01

    The aim of this work was to modify the standing posture of the anthropomorphic reference phantoms of ICRP publication 110, AM (Adult Male) and AF (Adult Female), to the sitting posture. The change of posture was performed using the Visual Monte Carlo software (VMC) to rotate the thigh region of the phantoms and position it between the region of the leg and trunk. Scion Image software was used to reconstruct and smooth the knee and hip contours of the phantoms in a sitting posture. For 3D visualization of phantoms, the VolView software was used. In the change of postures, the organ and tissue masses were preserved. The MCNPX was used to calculate the equivalent and effective dose conversion coefficients (CCs) per fluence for photons for six irradiation geometries suggested by ICRP publication 110 (AP, PA, RLAT, LLAT, ROT and ISO) and energy range 0.010-10 MeV. The results were compared between the standing and sitting postures, for both sexes, in order to evaluate the differences of scattering and absorption of radiation for different postures. Significant differences in the CCs for equivalent dose were observed in the gonads, colon, prostate, urinary bladder and uterus, which are present in the pelvic region, and in organs distributed throughout the body, such as the lymphatic nodes, muscle, skeleton and skin, for the phantoms of both sexes. CCs for effective dose showed significant differences of up to 16% in the AP irradiation geometry, 27% in the PA irradiation geometry and 13% in the ROT irradiation geometry. These results demonstrate the importance of using phantoms in different postures in order to obtain more precise conversion coefficients for a given exposure scenario.

  4. Electron specific absorbed fractions for the adult male and female ICRP/ICRU reference computational phantoms.

    PubMed

    Zankl, Maria; Schlattl, Helmut; Petoussi-Henss, Nina; Hoeschen, Christoph

    2012-07-21

    The calculation of radiation dose from internally incorporated radionuclides is based on so-called absorbed fractions (AFs) and specific absorbed fractions (SAFs). SAFs for monoenergetic electrons were calculated for 63 source regions and 67 target regions using the new male and female adult reference computational phantoms adopted by the ICRP and ICRU and the Monte Carlo radiation transport programme package EGSnrc. The SAF values for electrons are opposed to the simplifying assumptions of ICRP Publication 30. The previously applied assumption of electrons being fully absorbed in the source organ itself is not always true at electron energies above approximately 300-500 keV. High-energy electrons have the ability to leave the source organ and, consequently, the electron SAFs for neighbouring organs can reach the same magnitude as those for photons for electron energies above 1 MeV. The reciprocity principle known for photons can be extended to electron SAFs as well, thus making cross-fire electron SAFs mass-independent. To quantify the impact of the improved electron dosimetry in comparison to the dosimetry using the simple assumptions of ICRP Publication 30, absorbed doses per administered activity of three radiopharmaceuticals were evaluated with and without explicit electron transport. The organ absorbed doses per administered activity for the two evaluation methods agree within 2%-3% for most organs for radionuclides with decay spectra having electron energies below a few hundred keV and within approximately 20% if higher electron energies are involved. An important exception is the urinary bladder wall, where the dose is overestimated by 60-150% using the simplified ICRP 30 approach for the radiopharmaceuticals of this study.

  5. Impact of patient weight on tumor visibility based on human-shaped phantom simulation study in PET imaging system

    NASA Astrophysics Data System (ADS)

    Musarudin, M.; Saripan, M. I.; Mashohor, S.; Saad, W. H. M.; Nordin, A. J.; Hashim, S.

    2015-10-01

    Energy window technique has been implemented in all positron emission tomography (PET) imaging protocol, with the aim to remove the unwanted low energy photons. Current practices in our institution however are performed by using default energy threshold level regardless of the weight of the patient. Phantom size, which represents the size of the patient's body, is the factor that determined the level of scatter fraction during PET imaging. Thus, the motivation of this study is to determine the optimum energy threshold level for different sizes of human-shaped phantom, to represent underweight, normal, overweight and obese patients. In this study, the scanner was modeled by using Monte Carlo code, version MCNP5. Five different sizes of elliptical-cylinder shaped of human-sized phantoms with diameter ranged from 15 to 30 cm were modeled. The tumor was modeled by a cylindrical line source filled with 1.02 MeV positron emitters at the center of the phantom. Various energy window widths, in the ranged of 10-50% were implemented to the data. In conclusion, the phantom mass volume did influence the scatter fraction within the volume. Bigger phantom caused more scattering events and thus led to coincidence counts lost. We evaluated the impact of phantom sizes on the sensitivity and visibility of the simulated models. Implementation of wider energy window improved the sensitivity of the system and retained the coincidence photons lost. Visibility of the tumor improved as an appropriate energy window implemented for the different sizes of phantom.

  6. [Can fruits and vegetables be used as substitute phantoms for normal human brain tissues in magnetic resonance imaging?].

    PubMed

    Teramoto, Daisuke; Ushioda, Yuichi; Sasaki, Ayaka; Sakurai, Yuki; Nagahama, Hiroshi; Nakamura, Manami; Sugimori, Hiroyuki; Sakata, Motomichi

    2013-10-01

    Various custom-made phantoms designed to optimize magnetic resonance imaging (MRI) sequences have been created and subsequently reported in JSRT. However, custom-made phantoms that correctly match the T1-value and T2-values of human brain tissue (gray matter and white matter) cannot be made easily or quickly. The aim of this project was to search for alternative materials, such as fruits and vegetables, for optimizing MRI sequences. The following eight fruits and vegetables were investigated: apple, tomato, melon, apple mango (Mangifera indica), banana, avocado, peach, and eggplant. Their potential was studied for use in modeling phantoms of normal human brain tissues. MRI (T1- and T2-weighted sequences) was performed on the human brain and the fruits and vegetables using various concentrations of contrast medium (gadolinium) in the same size tubes as the custom-made phantom. The authors compared the signal intensity (SI) in human brain tissue (gray matter and white matter) with that of the fruits and the custom-made phantom. The T1 and T2 values were measured for banana tissue and compared with those for human brain tissue in the literature. Our results indicated that banana tissue is similar to human brain tissue (both gray matter and white matter). Banana tissue can thus be employed as an alternative phantom for the human brain for the purpose of MRI.

  7. Optical coherence tomography technique for noninvasive blood glucose monitoring: phantom, animal, and human studies

    NASA Astrophysics Data System (ADS)

    Larin, Kirill V.; Ashitkov, Taras V.; Larina, Irina V.; Petrova, Irina Y.; Eledrisi, Mohsen S.; Motamedi, Massoud; Esenaliev, Rinat O.

    2002-06-01

    Continuous noninvasive monitoring of blood glucose concentration can improve management of Diabetes Mellitus, reduce mortality, and considerably improve quality of life of diabetic patients. Recently, we proposed to use the OCT technique for noninvasive glucose monitoring. In this paper, we tested noninvasive blood glucose monitoring with the OCT technique in phantoms, animals, and human subjects. An OCT system with the wavelength of 1300 nm was used in our experiments. Phantom studies performed on aqueous suspensions of polystyrene microspheres and milk showed 3.2% decrease of exponential slope of OCT signals when glucose concentration increased from 0 to 100 mM. Theoretical calculations based on the Mie theory of scattering support the results obtained in phantoms. Bolus glucose injections and glucose clamping experiments were performed in animals (New Zealand rabbits and Yucatan micropigs). Good correlation between changes in the OCT signal slope and actual blood glucose concentration were observed in these experiments. First studies were performed in healthy human subjects (using oral glucose tolerance tests). Dependence of the slope of the OCT signals on the actual blood glucose concentration was similar to that obtained in animal studies. Our studies suggest that the OCT technique can potentially be used for noninvasive blood glucose monitoring.

  8. Large scale study on the variation of RF energy absorption in the head & brain regions of adults and children and evaluation of the SAM phantom conservativeness

    NASA Astrophysics Data System (ADS)

    Keshvari, J.; Kivento, M.; Christ, A.; Bit-Babik, G.

    2016-04-01

    This paper presents the results of two computational large scale studies using highly realistic exposure scenarios, MRI based human head and hand models, and two mobile phone models. The objectives are (i) to study the relevance of age when people are exposed to RF by comparing adult and child heads and (ii) to analyze and discuss the conservativeness of the SAM phantom for all age groups. Representative use conditions were simulated using detailed CAD models of two mobile phones operating between 900 MHz and 1950 MHz including configurations with the hand holding the phone, which were not considered in most previous studies. The peak spatial-average specific absorption rate (psSAR) in the head and the pinna tissues is assessed using anatomically accurate head and hand models. The first of the two mentioned studies involved nine head-, four hand- and two phone-models, the second study included six head-, four hand- and three simplified phone-models (over 400 configurations in total). In addition, both studies also evaluated the exposure using the SAM phantom. Results show no systematic differences between psSAR induced in the adult and child heads. The exposure level and its variation for different age groups may be different for particular phones, but no correlation between psSAR and model age was found. The psSAR from all exposure conditions was compared to the corresponding configurations using SAM, which was found to be conservative in the large majority of cases.

  9. Investigation of photothermolysis therapy of human skin diseases using optical phantoms

    NASA Astrophysics Data System (ADS)

    Jedrzejewska-Szczerska, M.; Wróbel, M. S.; Galla, S.; Popov, A. P.; Bykov, A. V.; Tuchin, V. V.; Cenian, A.

    2015-01-01

    Dermatological diseases, such as neurofibroma (Recklinghausen disease) or hemangiomas can be efficiently treated using photothermolysis from laser irradiation. We have utilized a developed 975 nm fiber diode laser as a low-cost alternative over common Nd:YAG lasers. This paper describes the investigations of interaction of 975 nm diode laser radiation-pulses with optical skin phantoms which were designed and manufactured in our laboratory. Such phantoms match the scattering and absorption coefficients of real human skin. Spatial and temporal temperature evolutions during laser irradiation with various laser settings (pulsed and CW mode), were recorded by an IR camera. Subsequent analysis yielded optimum choice of parameters for laser therapy of coetaneous lesions.

  10. Arts & Humanities in Adult Education.

    ERIC Educational Resources Information Center

    Word's Worth: A Quarterly Newsletter of the Lifelong Learning Network, 1998

    1998-01-01

    This issue of a quarterly newsletter on lifelong learning focuses on the theme of the arts and humanities in adult literacy education. The following articles are included: (1) "In Defense of a Practical Education" (Earl Shorris); (2) "From the Program Director" (Elizabeth Bryant McCrary); (3) "Vermont Council on the Humanities: Book Discussion…

  11. Study Of Dose Distribution In A Human Body In Space Flight With The Spherical Tissue-Equivalent Phantom

    NASA Astrophysics Data System (ADS)

    Shurshakov, Vyacheslav; Akatov, Yu; Petrov, V.; Kartsev, I.; Polenov, Boris; Petrov, V.; Lyagushin, V.

    In the space experiment MATROSHKA-R, the spherical tissue equivalent phantom (30 kg mass, 35 cm diameter and 10 cm central spherical cave) made in Russia has been installed in the star board crew cabin of the ISS Service Module. Due to the specially chosen phantom shape and size, the chord length distributions of the detector locations are attributed to self-shielding properties of the critical organs in a real human body. If compared with the anthropomorphic phantom Rando used inside and outside the ISS, the spherical phantom has lower mass, smaller size, and requires less crew time for the detector retrieval; its tissue-equivalent properties are closer to the standard human body tissue than the Rando-phantom material. In the first phase of the experiment the dose measurements were realized with only passive detectors (thermoluminescent and solid state track detectors). There were two experimental sessions with the spherical phantom in the crew cabin, (1) from Jan. 29, 2004 to Apr. 30, 2004 and (2) from Aug. 11, 2004 to Oct. 10, 2005. The detectors are placed inside the phantom along the axes of 20 containers and on the phantom outer surface in 32 pockets of the phantom jacket. The results obtained with the passive detectors returned to the ground after each session show the dose difference on the phantom surface as much as a factor of 2, the highest dose being observed close to the outer wall of the crew cabin, and the lowest dose being in the opposite location along the phantom diameter. Maximum dose rate measured in the phantom (0.31 mGy/day) is obviously due to the galactic cosmic ray (GCR) and Earth' radiation belt contribution on the ISS trajectory. Minimum dose rate (0.15 mGy/day) is caused mainly by the strongly penetrating GCR particles and is observed behind more than 5 g/cm2 tissue shielding. Critical organ doses, mean-tissue and effective doses of a crew member in the crew cabin are also estimated with the spherical phantom. The estimated effective

  12. Phantom and animal tissues for modelling the electrical properties of human liver.

    PubMed

    Stauffer, P R; Rossetto, F; Prakash, M; Neuman, D G; Lee, T

    2003-01-01

    The dielectric properties of human liver were characterized over the frequency range of 0.3-3 GHz for freshly excised tissue samples of primary hepatocellular carcinoma, metastatic colorectal carcinoma, and normal liver tissues resected from the tumour margin. On average, the dielectric constant (epsilon(r)) of freshly excised human liver tumour was 12% higher than that of surrounding normal liver, and the electrical conductivity (sigma) of tumour was 24% higher. In order to establish suitable tissue models for human liver, the electrical properties were compared to measurements of homogenous phantom mixtures, in vitro bovine liver, and in vivo canine and porcine liver tissues. The data demonstrate that there are several animal tissues that can be used to model the average dielectric properties of human liver reasonably accurately, and use of the most readily available bovine liver appears well-justified, even when stored for up to 10 days in a refrigerator. Additionally, the dielectric properties of in vitro liver remained stable over a large temperature range, with sigma rising only 1.1%/ degrees C in porcine liver (15-37 degrees C) and 2.0%/ degrees C in bovine liver (10-90 degrees C), and epsilon(r) decreasing < or =0.2%/ degrees C in both tissues. This effort identifies homogeneous solid and liquid phantom models and several heterogeneous in vitro tissues that adequately model the dielectric properties of human liver tumours for use in quantitative studies of microwave power deposition in liver.

  13. Experimental verification of internal dosimetry calculations: Construction of a heterogeneous phantom based on human organs

    NASA Astrophysics Data System (ADS)

    Lauridsen, Bente; Hedemann Jensen, Per

    1987-03-01

    The basic dosimetric quantity in ICRP-publication no. 30 is the aborbed fraction AF( T←S). This parameter is the fraction of energy absorbed in a target organ T per emission of radiation from activity deposited in the source organ S. Based upon this fraction it is possible to calculate the Specific Effective Energy SEE( T← S). From this, the committed effective dose equivalent from an intake of radioactive material can be found, and thus the annual limit of intake for given radionuclides can be determined. A male phantom has been constructed with the aim of measuring the Specific Effective Energy SEE(T←S) in various target organs. Impressions-of real human organs have been used to produce vacuum forms. Tissue equivalent plastic sheets were sucked into the vacuum forms producing a shell with a shape identical to the original organ. Each organ has been made of two shells. The same procedure has been used for the body. Thin tubes through the organs make it possible to place TL dose meters in a matrix so the dose distribution can be measured. The phantom has been supplied with lungs, liver, kidneys, spleen, stomach, bladder, pancreas, and thyroid gland. To select a suitable body liquid for the phantom, laboratory experiments have been made with different liquids and different radionuclides. In these experiments the change in dose rate due to changes in density and composition of the liquid was determined. Preliminary results of the experiments are presented.

  14. Red bone marrow dose calculations in radiotherapy of prostate cancer based on the updated VCH adult male phantom

    NASA Astrophysics Data System (ADS)

    Ai, Jinqin; Xie, Tianwu; Sun, Wenjuan; Liu, Qian

    2014-04-01

    Red bone marrow (RBM) is an important dose-limiting tissue that has high radiosensitivity but is difficult to identify on clinical medical images. In this study, we investigated dose distribution in RBM for prostate cancer radiotherapy. Four suborgans were identified in the skeleton of the visible Chinese human phantom: cortical bone (CB), trabecular bone (TB), RBM, and yellow bone marrow (YBM). Dose distributions in the phantom were evaluated by the Monte Carlo method. When the left os coxae was taken as the organ-at-risk (OAR), the difference in absorbed dose between RBM and each CB and TB was up to 20%, but was much less (≤3.1%) between RBM and YBM. When the left os coxae and entire bone were both taken as OARs, RBM dose also increased with increasing planning target volume size. The results indicate the validity of using dose to homogeneous bone marrow mixture for estimating dose to RBM when RBM is not available in computational phantoms. In addition, the human skeletal system developed in this study provides a model for considering RBM dose in radiotherapy planning.

  15. Study of dose distribution in a human body in international space station compartments with the tissue-equivalent spherical phantom

    PubMed Central

    Shurshakov, Vyacheslav A.; Tolochek, Raisa V.; Kartsev, Ivan S.; Petrov, Vladislav M.; Nikolaev, Igor V.; Moskalyova, Svetlana I.; Lyagushin, Vladimir I.

    2014-01-01

    Space radiation is known to be key hazard of manned space mission. To estimate accurately radiation health risk detailed study of dose distribution inside human body by means of human phantom is conducted. In the space experiment MATROSHKA-R, the tissue-equivalent spherical phantom (32 kg mass, 35 cm diameter and 10 cm central spherical cave) made in Russia has been used on board the ISS for more than 8 years. Owing to the specially chosen phantom shape and size, the chord length distributions of the detector locations are attributed to self-shielding properties of the critical organs in a real human body. If compared with the anthropomorphic phantom Rando used inside and outside the ISS, the spherical phantom has lower mass, smaller size and requires less crew time for the detector installation/retrieval; its tissue-equivalent properties are closer to the standard human body tissue than the Rando-phantom material. Originally the spherical phantom was installed in the star board crew cabin of the ISS Service Module, then in the Piers-1, MIM-2 and MIM-1 modules of the ISS Russian segment, and finally in JAXA Kibo module. Total duration of the detector exposure is more than 1700 days in 8 sessions. In the first phase of the experiment with the spherical phantom, the dose measurements were realized with only passive detectors (thermoluminescent and solid-state track detectors). The detectors are placed inside the phantom along the axes of 20 containers and on the phantom outer surface in 32 pockets of the phantom jacket. After each session the passive detectors are returned to the ground. The results obtained show the dose difference on the phantom surface as much as a factor of 2, the highest dose being observed close to the outer wall of the compartment, and the lowest dose being in the opposite location along the phantom diameter. Maximum dose rate measured in the phantom is obviously due to the galactic cosmic ray (GCR) and Earth' radiation belt contribution on

  16. Software-based Diffusion MR Human Brain Phantom for Evaluating Fiber-tracking Algorithms.

    PubMed

    Shi, Yundi; Roger, Gwendoline; Vachet, Clement; Budin, Francois; Maltbie, Eric; Verde, Audrey; Hoogstoel, Marion; Berger, Jean-Baptiste; Styner, Martin

    2013-03-13

    Fiber tracking provides insights into the brain white matter network and has become more and more popular in diffusion MR imaging. Hardware or software phantom provides an essential platform to investigate, validate and compare various tractography algorithms towards a "gold standard". Software phantoms excel due to their flexibility in varying imaging parameters, such as tissue composition, SNR, as well as potential to model various anatomies and pathologies. This paper describes a novel method in generating diffusion MR images with various imaging parameters from realistically appearing, individually varying brain anatomy based on predefined fiber tracts within a high-resolution human brain atlas. Specifically, joint, high resolution DWI and structural MRI brain atlases were constructed with images acquired from 6 healthy subjects (age 22-26) for the DWI data and 56 healthy subject (age 18-59) for the structural MRI data. Full brain fiber tracking was performed with filtered, two-tensor tractography in atlas space. A deformation field based principal component model from the structural MRI as well as unbiased atlas building was then employed to generate synthetic structural brain MR images that are individually varying. Atlas fiber tracts were accordingly warped into each synthetic brain anatomy. Diffusion MR images were finally computed from these warped tracts via a composite hindered and restricted model of diffusion with various imaging parameters for gradient directions, image resolution and SNR. Furthermore, an open-source program was developed to evaluate the fiber tracking results both qualitatively and quantitatively based on various similarity measures. PMID:24357914

  17. Ion therapy for uveal melanoma in new human eye phantom based on GEANT4 toolkit.

    PubMed

    Mahdipour, Seyed Ali; Mowlavi, Ali Asghar

    2016-01-01

    Radiotherapy with ion beams like proton and carbon has been used for treatment of eye uveal melanoma for many years. In this research, we have developed a new phantom of human eye for Monte Carlo simulation of tumors treatment to use in GEANT4 toolkit. Total depth-dose profiles for the proton, alpha, and carbon incident beams with the same ranges have been calculated in the phantom. Moreover, the deposited energy of the secondary particles for each of the primary beams is calculated. The dose curves are compared for 47.8MeV proton, 190.1MeV alpha, and 1060MeV carbon ions that have the same range in the target region reaching to the center of tumor. The passively scattered spread-out Bragg peak (SOBP) for each incident beam as well as the flux curves of the secondary particles including neutron, gamma, and positron has been calculated and compared for the primary beams. The high sharpness of carbon beam׳s Bragg peak with low lateral broadening is the benefit of this beam in hadrontherapy but it has disadvantages of dose leakage in the tail after its Bragg peak and high intensity of neutron production. However, proton beam, which has a good conformation with tumor shape owing to the beam broadening caused by scattering, can be a good choice for the large-size tumors. PMID:26831752

  18. Digital Anthropomorphic Phantoms of Non-Rigid Human Respiratory and Voluntary Body Motion for Investigating Motion Correction in Emission Imaging

    PubMed Central

    Könik, Arda; Connolly, Caitlin M; Johnson, Karen L; Dasari, Paul; Segars, Paul W; Pretorius, P H; Lindsay, Clifford; Dey, Joyoni; King, Michael A

    2014-01-01

    The development of methods for correcting patient motion in emission tomography has been receiving increased attention. Often performance of these methods is evaluated through simulations using digital anthropomorphic phantoms, such as the commonly used XCAT phantom, which models both respiratory and cardiac motion based on human studies. However, non-rigid body motion, which is frequently seen in clinical studies, is not present in the standard XCAT phantom. In addition, respiratory motion in the standard phantom is limited to a single generic trend. In this work, to obtain more realistic representation of motion, we developed a series of individual-specific XCAT phantoms modeling non-rigid respiratory and non-rigid body motions derived from the MRI acquisitions of volunteers. Acquisitions were performed in the sagittal orientation using the Navigator methodology. Baseline (no motion) acquisitions at end-expiration were obtained at the beginning of each imaging session for each volunteer. For the body motion studies, MRI was again acquired only at end-expiration for five body motion poses (shoulder stretch, shoulder twist, lateral bend, side roll, and axial slide). For the respiratory motion studies, MRI was acquired during free/regular breathing. The MR slices were then retrospectively sorted into 14 amplitude-binned respiratory states, end-expiration, end-inspiration, six intermediary states during inspiration, and six during expiration using the recorded Navigator signal. XCAT phantoms were then generated based on these MRI data by interactive alignment of the organ contours of the XCAT with the MRI slices using a GUI. Thus far we have created 5 body motion and 5 respiratory motion XCAT phantoms from MRI acquisitions of 6 healthy volunteers (3 males and 3 females). Non-rigid motion exhibited by the volunteers was reflected in both respiratory and body motion phantoms with a varying extent and character for each individual. In addition to these phantoms, we

  19. A DXA Whole Body Composition Cross-Calibration Experience: Evaluation With Humans, Spine, and Whole Body Phantoms.

    PubMed

    Krueger, Diane; Libber, Jessie; Sanfilippo, Jennifer; Yu, Hui Jing; Horvath, Blaine; Miller, Colin G; Binkley, Neil

    2016-01-01

    New densitometer installation requires cross-calibration for accurate longitudinal assessment. When replacing a unit with the same model, the International Society for Clinical Densitometry recommends cross-calibrating by scanning phantoms 10 times on each instrument and states that spine bone mineral density (BMD) should be within 1%, whereas total body lean, fat, and %fat mass should be within 2% of the prior instrument. However, there is limited validation that these recommendations provide adequate total body cross-calibration. Here, we report a total body cross-calibration experience with phantoms and humans. Cross-calibration between an existing and new Lunar iDXA was performed using 3 encapsulated spine phantoms (GE [GE Lunar, Madison, WI], BioClinica [BioClinica Inc, Princeton, NJ], and Hologic [Hologic Inc, Bedford, MA]), 1 total body composition phantom (BioClinica), and 30 human volunteers. Thirty scans of each phantom and a total body scan of human volunteers were obtained on each instrument. All spine phantom BMD means were similar (within 1%; <-0.010 g/cm2 bias) between the existing and new dual-energy X-ray absorptiometry unit. The BioClinica body composition phantom (BBCP) BMD and bone mineral content (BMC) values were within 2% with biases of 0.005 g/cm2 and -3.4 g. However, lean and fat mass and %fat differed by 4.6%-7.7% with biases of +463 g, -496 g, and -2.8%, respectively. In vivo comparison supported BBCP data; BMD and BMC were within ∼2%, but lean and fat mass and %fat differed from 1.6% to 4.9% with biases of +833 g, -860 g, and -1.1%. As all body composition comparisons exceeded the recommended 2%, the new densitometer was recalibrated. After recalibration, in vivo bias was lower (<0.05%) for lean and fat; -23 and -5 g, respectively. Similarly, BBCP lean and fat agreement improved. In conclusion, the BBCP behaves similarly, but not identical, to human in vivo measurements for densitometer cross-calibration. Spine phantoms, despite good

  20. Design of a phantom equivalent to measure bone-fluorine in a human's hand via delayed neutron activation analysis.

    PubMed

    Mostafaei, F; McNeill, F E; Chettle, D R; Prestwich, W V; Inskip, M

    2013-05-01

    Fluorine is an element that can be either beneficial or harmful, depending on the total amount accumulated in the teeth or bones. In our laboratory, we have developed a non-invasive technique for the in vivo measurement of fluoride in bone using neutron activation analysis and performed the first pilot human study. Fluoride in humans is quantified by comparing the γ-ray signal from a person to the γ-ray signal obtained from appropriate anthropomorphic calibration phantoms. An identified problem with existing fluoride phantoms is contamination with aluminum. Aluminum creates an interfering γ-ray signal which, although it can be subtracted out, increases the uncertainty in the measurement and worsens the detection limit. This paper outlines a series of studies undertaken to develop a better calibration phantom for fluorine measurement, which does not have aluminum contamination. PMID:23587669

  1. Wireless Performance of a Fully Passive Neurorecording Microsystem Embedded in Dispersive Human Head Phantom

    NASA Technical Reports Server (NTRS)

    Schwerdt, Helen N.; Chae, Junseok; Miranda, Felix A.

    2012-01-01

    This paper reports the wireless performance of a biocompatible fully passive microsystem implanted in phantom media simulating the dispersive dielectric properties of the human head, for potential application in recording cortical neuropotentials. Fully passive wireless operation is achieved by means of backscattering electromagnetic (EM) waves carrying 3rd order harmonic mixing products (2f(sub 0) plus or minus f(sub m)=4.4-4.9 GHZ) containing targeted neuropotential signals (fm approximately equal to 1-1000 Hz). The microsystem is enclosed in 4 micrometer thick parylene-C for biocompatibility and has a footprint of 4 millimeters x 12 millimeters x 500 micrometers. Preliminary testing of the microsystem implanted in the lossy biological simulating media results in signal-to-noise ratio's (SNR) near 22 (SNR approximately equal to 38 in free space) for millivolt level neuropotentials, demonstrating the potential for fully passive wireless microsystems in implantable medical applications.

  2. New conversion factors between human and automatic readouts of the CDMAM phantom for CR systems

    NASA Astrophysics Data System (ADS)

    Hummel, Johann; Homolka, Peter; Osanna-Elliot, Angelika; Kaar, Marcus; Semtrus, Friedrich; Figl, Michael

    2016-03-01

    Mammography screenings demand for profound image quality (IQ) assessment to guarantee their screening success. The European protocol for the quality control of the physical and technical aspects of mammography screening (EPQCM) suggests a contrast detail phantom such as the CDMAM phantom to evaluate IQ. For automatic evaluation a software is provided by the EUREF. As human and automatic readouts differ systematically conversion factors were published by the official reference organisation (EUREF). As we experienced a significant difference for these factors for Computed Radiography (CR) systems we developed an objectifying analysis software which presents the cells including the gold disks randomly in thickness and rotation. This allows to overcome the problem of an inevitable learning effect where observers know the position of the disks in advance. Applying this software, 45 computed radiography (CR) systems were evaluated and the conversion factors between human and automatic readout determined. The resulting conversion factors were compared with the ones resulting from the two methods published by EUREF. We found our conversion factors to be substantially lower than those suggested by EUREF, in particular 1.21 compared to 1.42 (EUREF EU method) and 1.62 (EUREF UK method) for 0.1 mm, and 1.40 compared to 1.73 (EUREF EU) and 1.83 (EUREF UK) for 0.25 mm disc diameter, respectively. This can result in a dose increase of up to 90% using either of these factors to adjust patient dose in order to fulfill image quality requirements. This suggests the need of an agreement on their proper application and limits the validity of the assessment methods. Therefore, we want to stress the need for clear criteria for CR systems based on appropriate studies.

  3. Generation of a suite of 3D computer-generated breast phantoms from a limited set of human subject data

    SciTech Connect

    Hsu, Christina M. L.; Palmeri, Mark L.; Segars, W. Paul; Veress, Alexander I.; Dobbins, James T. III

    2013-04-15

    Purpose: The authors previously reported on a three-dimensional computer-generated breast phantom, based on empirical human image data, including a realistic finite-element based compression model that was capable of simulating multimodality imaging data. The computerized breast phantoms are a hybrid of two phantom generation techniques, combining empirical breast CT (bCT) data with flexible computer graphics techniques. However, to date, these phantoms have been based on single human subjects. In this paper, the authors report on a new method to generate multiple phantoms, simulating additional subjects from the limited set of original dedicated breast CT data. The authors developed an image morphing technique to construct new phantoms by gradually transitioning between two human subject datasets, with the potential to generate hundreds of additional pseudoindependent phantoms from the limited bCT cases. The authors conducted a preliminary subjective assessment with a limited number of observers (n= 4) to illustrate how realistic the simulated images generated with the pseudoindependent phantoms appeared. Methods: Several mesh-based geometric transformations were developed to generate distorted breast datasets from the original human subject data. Segmented bCT data from two different human subjects were used as the 'base' and 'target' for morphing. Several combinations of transformations were applied to morph between the 'base' and 'target' datasets such as changing the breast shape, rotating the glandular data, and changing the distribution of the glandular tissue. Following the morphing, regions of skin and fat were assigned to the morphed dataset in order to appropriately assign mechanical properties during the compression simulation. The resulting morphed breast was compressed using a finite element algorithm and simulated mammograms were generated using techniques described previously. Sixty-two simulated mammograms, generated from morphing three human

  4. Development of a new forming process to fabricate a wide range of phantoms that highly match the acoustical properties of human bone

    NASA Astrophysics Data System (ADS)

    Wydra, Adrian

    In the various stages of developing diagnostic and therapeutic equipment, the use of phantoms can play a very important role in improving the process, and help with implementation, testing and calibrations. However, devices that use different physical factors, such as MRI, Ultrasound, CT Scan, etc. require the phantom to be made with different physical properties. This thesis deals with ultrasound and it introduces a novel composite material and a new forming process to fabricate a wide range of phantoms that highly match the acoustical properties of human bones. In contrast to ex vivo tissues, the proposed material can maintain its custom designed physical and acoustical properties unchanged for long periods of time. As results, the author introduces examples of already manufactured ultrasound phantoms (i.e. human head phantom) and a novel method of simultaneous measurements of skull thickness and its sound velocity using a set of skull bone phantoms.

  5. ICRP Publication 116—the first ICRP/ICRU application of the male and female adult reference computational phantoms

    NASA Astrophysics Data System (ADS)

    Petoussi-Henss, Nina; Bolch, Wesley E.; Eckerman, Keith F.; Endo, Akira; Hertel, Nolan; Hunt, John; Menzel, Hans G.; Pelliccioni, Maurizio; Schlattl, Helmut; Zankl, Maria

    2014-09-01

    ICRP Publication 116 on ‘Conversion coefficients for radiological protection quantities for external radiation exposures’, provides fluence-to-dose conversion coefficients for organ-absorbed doses and effective dose for various types of external exposures (ICRP 2010 ICRP Publication 116). The publication supersedes the ICRP Publication 74 (ICRP 1996 ICRP Publication 74, ICRU 1998 ICRU Report 57), including new particle types and expanding the energy ranges considered. The coefficients were calculated using the ICRP/ICRU computational phantoms (ICRP 2009 ICRP Publication 110) representing the reference adult male and reference adult female (ICRP 2002 ICRP Publication 89), together with a variety of Monte Carlo codes simulating the radiation transport in the body. Idealized whole-body irradiation from unidirectional and rotational parallel beams as well as isotropic irradiation was considered for a large variety of incident radiations and energy ranges. Comparison of the effective doses with operational quantities revealed that the latter quantities continue to provide a good approximation of effective dose for photons, neutrons and electrons for the ‘conventional’ energy ranges considered previously (ICRP 1996, ICRU 1998), but not at the higher energies of ICRP Publication 116.

  6. ICRP Publication 116--the first ICRP/ICRU application of the male and female adult reference computational phantoms.

    PubMed

    Petoussi-Henss, Nina; Bolch, Wesley E; Eckerman, Keith F; Endo, Akira; Hertel, Nolan; Hunt, John; Menzel, Hans G; Pelliccioni, Maurizio; Schlattl, Helmut; Zankl, Maria

    2014-09-21

    ICRP Publication 116 on 'Conversion coefficients for radiological protection quantities for external radiation exposures', provides fluence-to-dose conversion coefficients for organ-absorbed doses and effective dose for various types of external exposures (ICRP 2010 ICRP Publication 116). The publication supersedes the ICRP Publication 74 (ICRP 1996 ICRP Publication 74, ICRU 1998 ICRU Report 57), including new particle types and expanding the energy ranges considered. The coefficients were calculated using the ICRP/ICRU computational phantoms (ICRP 2009 ICRP Publication 110) representing the reference adult male and reference adult female (ICRP 2002 ICRP Publication 89), together with a variety of Monte Carlo codes simulating the radiation transport in the body. Idealized whole-body irradiation from unidirectional and rotational parallel beams as well as isotropic irradiation was considered for a large variety of incident radiations and energy ranges. Comparison of the effective doses with operational quantities revealed that the latter quantities continue to provide a good approximation of effective dose for photons, neutrons and electrons for the 'conventional' energy ranges considered previously (ICRP 1996, ICRU 1998), but not at the higher energies of ICRP Publication 116. PMID:25144220

  7. Effect of leaded glasses and thyroid shielding on cone beam CT radiation dose in an adult female phantom

    PubMed Central

    Goren, AD; Prins, RD; Dauer, LT; Quinn, B; Al-Najjar, A; Faber, RD; Patchell, G; Branets, I; Colosi, DC

    2013-01-01

    Objectives: This study aims to demonstrate the effectiveness of leaded glasses in reducing the lens of eye dose and of lead thyroid collars in reducing the dose to the thyroid gland of an adult female from dental cone beam CT (CBCT). The effect of collimation on the radiation dose in head organs is also examined. Methods: Dose measurements were conducted by placing optically stimulated luminescent dosemeters in an anthropomorphic female phantom. Eye lens dose was measured by placing a dosemeter on the anterior surface of the phantom eye location. All exposures were performed on one commercially available dental CBCT machine, using selected collimation and exposure techniques. Each scan technique was performed without any lead shielding and then repeated with lead shielding in place. To calculate the percent reduction from lead shielding, the dose measured with lead shielding was divided by the dose measured without lead shielding. The percent reduction from collimation was calculated by comparing the dose measured with collimation to the dose measured without collimation. Results: The dose to the internal eye for one of the scans without leaded glasses or thyroid shield was 0.450 cGy and with glasses and thyroid shield was 0.116 cGy (a 74% reduction). The reduction to the lens of the eye was from 0.396 cGy to 0.153 cGy (a 61% reduction). Without glasses or thyroid shield, the thyroid dose was 0.158 cGy; and when both glasses and shield were used, the thyroid dose was reduced to 0.091 cGy (a 42% reduction). Conclusions: Collimation alone reduced the dose to the brain by up to 91%, with a similar reduction in other organs. Based on these data, leaded glasses, thyroid collars and collimation minimize the dose to organs outside the field of view. PMID:23412460

  8. Extension of RPI-adult male and female computational phantoms to obese patients and a Monte Carlo study of the effect on CT imaging dose

    NASA Astrophysics Data System (ADS)

    Ding, Aiping; Mille, Matthew M.; Liu, Tianyu; Caracappa, Peter F.; Xu, X. George

    2012-05-01

    Although it is known that obesity has a profound effect on x-ray computed tomography (CT) image quality and patient organ dose, quantitative data describing this relationship are not currently available. This study examines the effect of obesity on the calculated radiation dose to organs and tissues from CT using newly developed phantoms representing overweight and obese patients. These phantoms were derived from the previously developed RPI-adult male and female computational phantoms. The result was a set of ten phantoms (five males, five females) with body mass indexes ranging from 23.5 (normal body weight) to 46.4 kg m-2 (morbidly obese). The phantoms were modeled using triangular mesh geometry and include specified amounts of the subcutaneous adipose tissue and visceral adipose tissue. The mesh-based phantoms were then voxelized and defined in the Monte Carlo N-Particle Extended code to calculate organ doses from CT imaging. Chest-abdomen-pelvis scanning protocols for a GE LightSpeed 16 scanner operating at 120 and 140 kVp were considered. It was found that for the same scanner operating parameters, radiation doses to organs deep in the abdomen (e.g., colon) can be up to 59% smaller for obese individuals compared to those of normal body weight. This effect was found to be less significant for shallow organs. On the other hand, increasing the tube potential from 120 to 140 kVp for the same obese individual resulted in increased organ doses by as much as 56% for organs within the scan field (e.g., stomach) and 62% for those out of the scan field (e.g., thyroid), respectively. As higher tube currents are often used for larger patients to maintain image quality, it was of interest to quantify the associated effective dose. It was found from this study that when the mAs was doubled for the obese level-I, obese level-II and morbidly-obese phantoms, the effective dose relative to that of the normal weight phantom increased by 57%, 42% and 23%, respectively. This set

  9. Spatio-temporal anomalous diffusion imaging: results in controlled phantoms and in excised human meningiomas.

    PubMed

    Capuani, Silvia; Palombo, Marco; Gabrielli, Andrea; Orlandi, Augusto; Maraviglia, Bruno; Pastore, Francesco S

    2013-04-01

    Recently, we measured two anomalous diffusion (AD) parameters: the spatial and the temporal AD indices, called γ and α, respectively, by using spectroscopic pulse gradient field methods. We showed that γ quantifies pseudo-superdiffusion processes, while α quantifies subdiffusion processes. Here, we propose γ and α maps obtained in a controlled heterogeneous phantom, comprised of packed micro-beads in water and in excised human meningiomas. In few words, α maps represent the multi-scale spatial distribution of the disorder degree in the system, while γ maps are influenced by local internal gradients, thus highlighting the interface between compartments characterized by different magnetic susceptibility. γ maps were already obtained by means of AD stretched exponential imaging and α-type maps have been recently achieved for fixed rat brain with the aim of highlighting the fractal dimension of specific brain regions. However, to our knowledge, the maps representative of the spatial distribution of α and γ obtained on the same controlled sample and in the same excised tissue have never been compared. Moreover, we show here, for the first time, that α maps are representative of the spatial distribution of the disorder degree of the system. In a first phase, γ and α maps of controlled phantom characterized by an ordered and a disordered rearrangement of packed micro-beads of different sizes in water and by different magnetic susceptibility (Δχ) between beads and water were obtained. In a second phase, we investigated excised human meningiomas of different consistency. Results reported here, obtained at 9.4T, show that α and γ maps are characterized by a different image contrast. Indeed, unlike γ maps, α maps are insensible to (Δχ) and they are sensible to the disorder degree of the microstructural rearrangement. These observations strongly suggest that AD indices α and γ reflect some additional microstructural information which cannot be obtained

  10. Conversion factors between human and automatic readouts of CDMAM phantom images of CR mammography systems

    NASA Astrophysics Data System (ADS)

    Figl, Michael; Homolka, Peter; Osanna-Elliott, Angelika; Semturs, Friedrich; Kaar, Marcus; Hummel, Johann

    2016-09-01

    In mammography screening, profound assessment of technical image quality is imperative. The European protocol for the quality control of the physical and technical aspects of mammography screening (EPQCM) suggests using an alternate fixed choice contrast-detail phantom-like CDMAM. For the evaluation of technical image quality, human or automated readouts can be used. For automatic evaluation, a software (cdcom) is provided by EUREF. If the automated readout indicates unacceptable image quality, additional human readout may be performed overriding the automated readout. As the latter systematically results in higher image quality ratings, conversion factors between both methods are regularly applied. Since most image quality issues with mammography systems arise within CR systems, an assessment restricted to CR systems with data from the Austrian Reference Center in the mammography screening program has been conducted. Forty-five CR systems were evaluated. Human readouts were performed with a randomisation software to avoid bias due to learning effects. Additional automatic evaluation allowed for the computation of conversion factors between human and automatic readouts. These factors were substantially lower compared to those suggested by EUREF, namely 1.21 compared to 1.62 (EUREF UK method) and 1.42 (EUREF EU method) for 0.1 mm, and 1.40 compared to 1.83 (EUREF UK) and 1.73 (EUREF EU) for 0.25 mm structure size, respectively. Using either of these factors to adjust patient dose in order to comply with image quality requirements results in differences in the dose increase of up to 90%. This necessitates a consensus on their proper application and limits the validity of the assessment methods. Clear criteria for CR systems based on appropriate studies should be promoted.

  11. Counting 241Am in the BfS human skull phantom on contact-evaluation in the human monitoring laboratory.

    PubMed

    Li, Chunsheng; Hauck, Barry; Capello, Kevin; Nogueira, Pedro; Lopez, Maria A; Kramer, Gary H

    2015-03-01

    Skull counting can be used to assess the activity of radionuclides internally deposited in the bone. The Human Monitoring Laboratory (HML) at Health Canada conducted the measurement of 241Am in the BfS (Bundesamt für Strahlenschuts) skull phantom on contact with the skull for various positions. By placing the detector in contact, the HML can improve the counting efficiency by over 20% compared to placing the detector 1 cm above the surface of the skull. Among all the positions tested, the forehead position is the preferred counting geometry due to the design of HML's counting facility and the comfort it would provide to the individual being counted, although this counting position did not offer the highest counting efficiency for the gamma rays (either the 59.5 keV or the 26.3 keV) emitted by 241Am.

  12. Counting 241Am in the BfS human skull phantom on contact-evaluation in the human monitoring laboratory.

    PubMed

    Li, Chunsheng; Hauck, Barry; Capello, Kevin; Nogueira, Pedro; Lopez, Maria A; Kramer, Gary H

    2015-03-01

    Skull counting can be used to assess the activity of radionuclides internally deposited in the bone. The Human Monitoring Laboratory (HML) at Health Canada conducted the measurement of 241Am in the BfS (Bundesamt für Strahlenschuts) skull phantom on contact with the skull for various positions. By placing the detector in contact, the HML can improve the counting efficiency by over 20% compared to placing the detector 1 cm above the surface of the skull. Among all the positions tested, the forehead position is the preferred counting geometry due to the design of HML's counting facility and the comfort it would provide to the individual being counted, although this counting position did not offer the highest counting efficiency for the gamma rays (either the 59.5 keV or the 26.3 keV) emitted by 241Am. PMID:25627952

  13. Modelling human exposure to space radiation with different shielding: the FLUKA code coupled with anthropomorphic phantoms

    NASA Astrophysics Data System (ADS)

    Ballarini, F.; Alloni, D.; Battistoni, G.; Cerutti, F.; Ferrari, A.; Gadioli, E.; Garzelli, M. V.; Liotta, M.; Mairani, A.; Ottolenghi, A.; Paretzke, H. G.; Parini, V.; Pelliccioni, M.; Pinsky, L.; Sala, P.; Scannicchio, D.; Trovati, S.; Zankl, M.

    2006-05-01

    Astronauts' exposure to the various components of the space radiation field is of great concern for long-term missions, especially for those in deep space such as a possible travel to Mars. Simulations based on radiation transport/interaction codes coupled with anthropomorphic model phantoms can be of great help in view of risk evaluation and shielding optimisation, which is therefore a crucial issue. The FLUKA Monte Carlo code can be coupled with two types of anthropomorphic phantom (a mathematical model and a ''voxel'' model) to calculate organ-averaged absorbed dose, dose equivalent and ''biological'' dose under different shielding conditions. Herein the ''biological dose'' is represented by the average number of ''Complex Lesions'' (CLs) per cell in a given organ. CLs are clustered DNA breaks previously calculated by means of event-by-event track structure simulations at the nm level and integrated on-line into FLUKA, which adopts a condensed-history approach; such lesions have been shown to play a fundamental role in chromosome aberration induction, which in turn can be correlated with carcinogenesis. Examples of calculation results will be presented relative to Galactic Cosmic Rays, as well as to the August 1972 Solar Particle Event. The contributions from primary ions and secondary particles will be shown separately, thus allowing quantification of the role played by nuclear reactions occurring in the shield and in the human body itself. As expected, the SPE doses decrease dramatically with increasing the Al shielding thickness; nuclear reaction products, essentially due to target fragmentation, are of minor importance. A 10 g/cm2 Al shelter resulted to be sufficient to respect the 30-day limits for deterministic effects recommended for missions in Low Earth Orbit. In contrast with the results obtained for SPEs, the calculated GCR doses are almost independent of the Al shield thickness, and the GCR doses to internal organs are not significantly lower than

  14. Organ doses, effective doses, and risk indices in adult CT: Comparison of four types of reference phantoms across different examination protocols

    SciTech Connect

    Zhang Yakun; Li Xiang; Paul Segars, W.; Samei, Ehsan

    2012-06-15

    Purpose: Radiation exposure from computed tomography (CT) to the public has increased the concern among radiation protection professionals. Being able to accurately assess the radiation dose patients receive during CT procedures is a crucial step in the management of CT dose. Currently, various computational anthropomorphic phantoms are used to assess radiation dose by different research groups. It is desirable to better understand how the dose results are affected by different choices of phantoms. In this study, the authors assessed the uncertainties in CT dose and risk estimation associated with different types of computational phantoms for a selected group of representative CT protocols. Methods: Routinely used CT examinations were categorized into ten body and three neurological examination categories. Organ doses, effective doses, risk indices, and conversion coefficients to effective dose and risk index (k and q factors, respectively) were estimated for these examinations for a clinical CT system (LightSpeed VCT, GE Healthcare). Four methods were used, each employing a different type of reference phantoms. The first and second methods employed a Monte Carlo program previously developed and validated in our laboratory. In the first method, the reference male and female extended cardiac-torso (XCAT) phantoms were used, which were initially created from the Visible Human data and later adjusted to match organ masses defined in ICRP publication 89. In the second method, the reference male and female phantoms described in ICRP publication 110 were used, which were initially developed from tomographic data of two patients and later modified to match ICRP 89 organ masses. The third method employed a commercial dosimetry spreadsheet (ImPACT group, London, England) with its own hermaphrodite stylized phantom. In the fourth method, another widely used dosimetry spreadsheet (CT-Expo, Medizinische Hochschule, Hannover, Germany) was employed together with its associated

  15. Coagulation of human prostate volumes with MRI-controlled transurethral ultrasound therapy: Results in gel phantoms

    PubMed Central

    N’Djin, William Apoutou; Burtnyk, Mathieu; Kobelevskiy, Ilya; Hadjis, Stefan; Bronskill, Michael; Chopra, Rajiv

    2012-01-01

    Purpose: The feasibility and safety of magnetic resonance imaging (MRI)-controlled transurethral ultrasound therapy were demonstrated recently in a preliminary human study in which a small subvolume of prostate tissue was treated prior to radical prostatectomy. Translation of this technology to full clinical use, however, requires the capability to generate thermal coagulation in a volume up to that of the prostate gland itself. The aim of this study was to investigate the parameters required to treat a full 3D human prostate accurately with a multi-element transurethral applicator and multiplanar MR temperature control. Methods: The approach was a combination of simulations (to select appropriate parameters) followed by experimental confirmation in tissue-mimicking phantoms. A ten-channel, MRI-compatible transurethral ultrasound therapy system was evaluated using six human prostate models (average volume: 36 cm3) obtained from the preliminary human feasibility study. Real-time multiplanar MR thermometry at 3 T was used to control the spatial heating pattern in up to nine planes simultaneously. Treatment strategies incorporated both single (4.6 or 8.1 MHz) and dual (4.6 and 14.4 MHz) frequencies, as well as maximum acoustic surface powers of 10 or 20 W cm−2. Results: Treatments at 4.6 MHz were capable of coagulating a volume equivalent to 97% of the prostate. Increasing power from 10 to 20 W cm−2 reduced treatment times by approximately 50% with full treatments taking 26 ± 3 min at a coagulation rate of 1.8 ± 0.4 cm3 min−1. A dual-frequency 4.6/14.4 MHz treatment strategy was shown to be the most effective configuration for achieving full human prostate treatment while maintaining good treatment accuracy for small treatment radii. The dual-frequency approach reduced overtreatment close to the prostate base and apex, confirming the simulations. Conclusions: This study reinforces the capability of MRI-controlled transurethral ultrasound therapy to treat

  16. Dose reduction and image quality optimizations in CT of pediatric and adult patients: phantom studies

    NASA Astrophysics Data System (ADS)

    Jeon, P.-H.; Lee, C.-L.; Kim, D.-H.; Lee, Y.-J.; Jeon, S.-S.; Kim, H.-J.

    2014-03-01

    Multi-detector computed tomography (MDCT) can be used to easily and rapidly perform numerous acquisitions, possibly leading to a marked increase in the radiation dose to individual patients. Technical options dedicated to automatically adjusting the acquisition parameters according to the patient's size are of specific interest in pediatric radiology. A constant tube potential reduction can be achieved for adults and children, while maintaining a constant detector energy fluence. To evaluate radiation dose, the weighted CT dose index (CTDIw) was calculated based on the CT dose index (CTDI) measured using an ion chamber, and image noise and image contrast were measured from a scanned image to evaluate image quality. The dose-weighted contrast-to-noise ratio (CNRD) was calculated from the radiation dose, image noise, and image contrast measured from a scanned image. The noise derivative (ND) is a quality index for dose efficiency. X-ray spectra with tube voltages ranging from 80 to 140 kVp were used to compute the average photon energy. Image contrast and the corresponding contrast-to-noise ratio (CNR) were determined for lesions of soft tissue, muscle, bone, and iodine relative to a uniform water background, as the iodine contrast increases at lower energy (i.e., k-edge of iodine is 33 keV closer to the beam energy) using mixed water-iodine contrast normalization (water 0, iodine 25, 100, 200, and 1000 HU, respectively). The proposed values correspond to high quality images and can be reduced if only high-contrast organs are assessed. The potential benefit of lowering the tube voltage is an improved CNRD, resulting in a lower radiation dose and optimization of image quality. Adjusting the tube potential in abdominal CT would be useful in current pediatric radiography, where the choice of X-ray techniques generally takes into account the size of the patient as well as the need to balance the conflicting requirements of diagnostic image quality and radiation dose

  17. Biplane correlation imaging: a feasibility study based on phantom and human data.

    PubMed

    Samei, Ehsan; Majdi-Nasab, Nariman; Dobbins, James T; McAdams, H Page

    2012-02-01

    The objective of this study was to implement and evaluate the performance of a biplane correlation imaging (BCI) technique aimed to reduce the effect of anatomic noise and improve the detection of lung nodules in chest radiographs. Seventy-one low-dose posterior-anterior images were acquired from an anthropomorphic chest phantom with 0.28° angular separations over a range of ±10° along the vertical axis within an 11 s interval. Similar data were acquired from 19 human subjects with institutional review board approval and informed consent. The data were incorporated into a computer-aided detection (CAD) algorithm in which suspect lesions were identified by examining the geometrical correlation of the detected signals that remained relatively constant against variable anatomic backgrounds. The data were analyzed to determine the effect of angular separation, and the overall sensitivity and false-positives for lung nodule detection. The best performance was achieved for angular separations of the projection pairs greater than 5°. Within that range, the technique provided an order of magnitude decrease in the number of false-positive reports when compared with CAD analysis of single-view images. Overall, the technique yielded ~1.1 false-positive per patient with an average sensitivity of 75%. The results indicated that the incorporation of angular information can offer a reduction in the number of false-positives without a notable reduction in sensitivity. The findings suggest that the BCI technique has the potential for clinical implementation as a cost-effective technique to improve the detection of subtle lung nodules with lowered rate of false-positives.

  18. The UF family of reference hybrid phantoms for computational radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Lee, Choonsik; Lodwick, Daniel; Hurtado, Jorge; Pafundi, Deanna; Williams, Jonathan L.; Bolch, Wesley E.

    2010-01-01

    Computational human phantoms are computer models used to obtain dose distributions within the human body exposed to internal or external radiation sources. In addition, they are increasingly used to develop detector efficiencies for in vivo whole-body counters. Two classes of computational human phantoms have been widely utilized for dosimetry calculation: stylized and voxel phantoms that describe human anatomy through mathematical surface equations and 3D voxel matrices, respectively. Stylized phantoms are flexible in that changes to organ position and shape are possible given avoidance of region overlap, while voxel phantoms are typically fixed to a given patient anatomy, yet can be proportionally scaled to match individuals of larger or smaller stature, but of equivalent organ anatomy. Voxel phantoms provide much better anatomical realism as compared to stylized phantoms which are intrinsically limited by mathematical surface equations. To address the drawbacks of these phantoms, hybrid phantoms based on non-uniform rational B-spline (NURBS) surfaces have been introduced wherein anthropomorphic flexibility and anatomic realism are both preserved. Researchers at the University of Florida have introduced a series of hybrid phantoms representing the ICRP Publication 89 reference newborn, 15 year, and adult male and female. In this study, six additional phantoms are added to the UF family of hybrid phantoms—those of the reference 1 year, 5 year and 10 year child. Head and torso CT images of patients whose ages were close to the targeted ages were obtained under approved protocols. Major organs and tissues were segmented from these images using an image processing software, 3D-DOCTOR™. NURBS and polygon mesh surfaces were then used to model individual organs and tissues after importing the segmented organ models to the 3D NURBS modeling software, Rhinoceros™. The phantoms were matched to four reference datasets: (1) standard anthropometric data, (2) reference

  19. Human Eye Phantom for Developing Computer and Robot-Assisted Epiretinal Membrane Peeling*

    PubMed Central

    Gupta, Amrita; Gonenc, Berk; Balicki, Marcin; Olds, Kevin; Handa, James; Gehlbach, Peter; Taylor, Russell H.; Iordachita, Iulian

    2014-01-01

    A number of technologies are being developed to facilitate key intraoperative actions in vitreoretinal microsurgery. There is a need for cost-effective, reusable benchtop eye phantoms to enable frequent evaluation of these developments. In this study, we describe an artificial eye phantom for developing intraocular imaging and force-sensing tools. We test four candidate materials for simulating epiretinal membranes using a handheld tremor-canceling micromanipulator with force-sensing micro-forceps tip and demonstrate peeling forces comparable to those encountered in clinical practice. PMID:25571573

  20. New small-intestine modeling method for surface-based computational human phantoms.

    PubMed

    Yeom, Yeon Soo; Kim, Han Sung; Nguyen, Thang Tat; Choi, Chansoo; Han, Min Cheol; Kim, Chan Hyeong; Lee, Jai Ki; Zankl, Maria; Petoussi-Henss, Nina; Bolch, Wesley E; Lee, Choonsik; Chung, Beom Sun

    2016-06-01

    When converting voxel phantoms to a surface format, the small intestine (SI), which is usually not accurately represented in a voxel phantom due to its complex and irregular shape on one hand and the limited voxel resolutions on the other, cannot be directly converted to a high-quality surface model. Currently, stylized pipe models are used instead, but they are strongly influenced by developer's subjectivity, resulting in unacceptable geometric and dosimetric inconsistencies. In this paper, we propose a new method for the construction of SI models based on the Monte Carlo approach. In the present study, the proposed method was tested by constructing the SI model for the polygon-mesh version of the ICRP reference male phantom currently under development. We believe that the new SI model is anatomically more realistic than the stylized SI models. Furthermore, our simulation results show that the new SI model, for both external and internal photon exposures, leads to dose values that are more similar to those of the original ICRP male voxel phantom than does the previously constructed stylized SI model. PMID:27007802

  1. A wideband spiral antenna for ingestible capsule endoscope systems: experimental results in a human phantom and a pig.

    PubMed

    Lee, Sang Heun; Lee, Jaebok; Yoon, Young Joong; Park, Sangbok; Cheon, Changyul; Kim, Kihyun; Nam, Sangwook

    2011-06-01

    This paper presents the design of a wideband spiral antenna for ingestible capsule endoscope systems and a comparison between the experimental results in a human phantom and a pig under general anesthesia. As wireless capsule endoscope systems transmit real-time internal biological image data at a high resolution to external receivers and because they operate in the human body, a small wideband antenna is required. To incorporate these properties, a thick-arm spiral structure is applied to the designed antenna. To make practical and efficient use of antennas inside the human body, which is composed of a high dielectric and lossy material, the resonance characteristics and radiation patterns were evaluated through a measurement setup using a liquid human phantom. The total height of the designed antenna is 5 mm and the diameter is 10 mm. The fractional bandwidth of the fabricated antenna is about 21% with a voltage standing-wave ratio of less than 2, and it has an isotropic radiation pattern. These characteristics are suitable for wideband capsule endoscope systems. Moreover, the received power level was measured using the proposed antenna, a circular polarized receiver antenna, and a pig under general anesthesia. Finally, endoscopic capsule images in the stomach and large intestine were captured using an on-off keying transceiver system.

  2. SU-E-I-81: Assessment of CT Radiation Dose and Image Quality for An Automated Tube Potential Selection Algorithm Using Adult Anthropomorphic and ACR Phantoms

    SciTech Connect

    Mahmood, U; Erdi, Y; Wang, W

    2014-06-01

    Purpose: To assess the impact of General Electrics (GE) automated tube potential algorithm, kV assist (kVa) on radiation dose and image quality, with an emphasis on optimizing protocols based on noise texture. Methods: Radiation dose was assessed by inserting optically stimulated luminescence dosimeters (OSLs) throughout the body of an adult anthropomorphic phantom (CIRS). The baseline protocol was: 120 kVp, Auto mA (180 to 380 mA), noise index (NI) = 14, adaptive iterative statistical reconstruction (ASiR) of 20%, 0.8s rotation time. Image quality was evaluated by calculating the contrast to noise ratio (CNR) and noise power spectrum (NPS) from the ACR CT accreditation phantom. CNRs were calculated according to the steps described in ACR CT phantom testing document. NPS was determined by taking the 3D FFT of the uniformity section of the ACR phantom. NPS and CNR were evaluated with and without kVa and for all available adaptive iterative statistical reconstruction (ASiR) settings, ranging from 0 to 100%. Each NPS was also evaluated for its peak frequency difference (PFD) with respect to the baseline protocol. Results: The CNR for the adult male was found to decrease from CNR = 0.912 ± 0.045 for the baseline protocol without kVa to a CNR = 0.756 ± 0.049 with kVa activated. When compared against the baseline protocol, the PFD at ASiR of 40% yielded a decrease in noise magnitude as realized by the increase in CNR = 0.903 ± 0.023. The difference in the central liver dose with and without kVa was found to be 0.07%. Conclusion: Dose reduction was insignificant in the adult phantom. As determined by NPS analysis, ASiR of 40% produced images with similar noise texture to the baseline protocol. However, the CNR at ASiR of 40% with kVa fails to meet the current ACR CNR passing requirement of 1.0.

  3. Results on Dose Distributions in a Human Body from the Matroshka-R Experiment onboard the ISS Obtained with the Tissue-Equivalent Spherical Phantom

    NASA Astrophysics Data System (ADS)

    Shurshakov, Vyacheslav; Nikolaev, Igor; Kartsev, Ivan; Tolochek, Raisa; Lyagushin, Vladimir

    The tissue-equivalent spherical phantom (32 kg mass, 35 cm diameter and 10 cm central spherical cave) made in Russia has been used on board the ISS in Matroshka-R experiment for more than 10 years. Both passive and active space radiation detectors can be located inside the phantom and on its surface. Due to the specially chosen phantom shape and size, the chord length distributions of the detector locations are attributed to self-shielding properties of the critical organs in a human body. Originally the spherical phantom was installed in the star board crew cabin of the ISS Service Module, then in the Piers-1, MIM-2, and MIM-1 modules of the ISS Russian segment, and finally in JAXA Kibo module. Total duration of the detector exposure is more than 2000 days in 9 sessions of the space experiment. In the first phase of the experiment with the spherical phantom the dose measurements were realized with only passive detectors (thermoluminescent and solid state track detectors). The detectors are placed inside the phantom along the axes of 20 containers and on the phantom outer surface in 32 pockets of the phantom jacket. After each session the passive detectors are returned to the ground. The results obtained show the dose difference on the phantom surface as much as a factor of 2, the highest dose being usually observed close to the outer wall of the compartment, and the lowest dose being in the opposite location along the phantom diameter. However, because of the ISS module shielding properties an inverse dose distribution in a human body can be observed when the dose rate maximum is closer to the geometrical center of the module. Maximum dose rate measured in the phantom is obviously due to the action of two radiation sources, namely, galactic cosmic rays (GCR) and Earth’ radiation belts. Minimum dose rate is produced mainly by the strongly penetrating GCR particles and is mostly observed behind more than 5 g/cm2 tissue shielding. Critical organ doses, mean

  4. Utilization of MAX and FAX human phantoms for space radiation exposure calculations using HZETRN

    NASA Astrophysics Data System (ADS)

    Qualls, Garry; Slaba, Tony; Clowdsley, Martha; Blattnig, Steve; Walker, Steven; Simonsen, Lisa

    To estimate astronaut health risk due to space radiation, one must have the ability to calculate, for known radiation environments external to the body, particle spectra, LET spectra, dose, dose equivalent, or gray equivalent that are averaged over specific organs or tissue types. This may be accomplished using radiation transport software and computational human body tissue models. Historically, NASA scientists have used the HZETRN software to calculate radiation transport through both vehicle shielding materials and body tissue. The Computerized Anatomical Man (CAM) and the Computerized Anatomical Female (CAF) body models, combined with the CAMERA software, have been used for body tissue self-shielding calculations. The CAM and CAF, which were developed in 1973 and 1992, respectively, model the 50th percentile U.S. Air Force male and female and are constructed using individual quadric surfaces that combine to form thousands of solid regions that represent specific tissues and structures within the body. In order to transport an external radiation environment to a point within one of the body models using HZETRN, a directional distribution of the tissues surrounding that point is needed. The CAMERA software is used to "ray trace" the CAM and CAF models, providing the thickness of each tissue type traversed along each of a large number of rays originating at a dose point. More recently, R. Kramer of the Departmento de Energia Nuclear, Universidade Federal de Pernambuco in Brazil and his co-workers developed the Male Adult voXel (MAX) model and the Female Adult voXel (FAX). These voxel-based body models were developed using segmented Computed Tomography (CT) scans of adult cadavers, and the quantities and distributions of various body tissues have been adjusted to match those specified in the International Commission on Radiological Protection (ICRP) reference adult male and female. A new set of tools has been developed to facilitate space radiation exposure

  5. The properties of human body phantoms used in calculations of electromagnetic fields exposure by wireless communication handsets or hand-operated industrial devices.

    PubMed

    Zradziński, Patryk

    2013-06-01

    According to international guidelines, the assessment of biophysical effects of exposure to electromagnetic fields (EMF) generated by hand-operated sources needs the evaluation of induced electric field (E(in)) or specific energy absorption rate (SAR) caused by EMF inside a worker's body and is usually done by the numerical simulations with different protocols applied to these two exposure cases. The crucial element of these simulations is the numerical phantom of the human body. Procedures of E(in) and SAR evaluation due to compliance analysis with exposure limits have been defined in Institute of Electrical and Electronics Engineers standards and International Commission on Non-Ionizing Radiation Protection guidelines, but a detailed specification of human body phantoms has not been described. An analysis of the properties of over 30 human body numerical phantoms was performed which has been used in recently published investigations related to the assessment of EMF exposure by various sources. The differences in applicability of these phantoms in the evaluation of E(in) and SAR while operating industrial devices and SAR while using mobile communication handsets are discussed. The whole human body numerical phantom dimensions, posture, spatial resolution and electric contact with the ground constitute the key parameters in modeling the exposure related to industrial devices, while modeling the exposure from mobile communication handsets, which needs only to represent the exposed part of the human body nearest to the handset, mainly depends on spatial resolution of the phantom. The specification and standardization of these parameters of numerical human body phantoms are key requirements to achieve comparable and reliable results from numerical simulations carried out for compliance analysis against exposure limits or within the exposure assessment in EMF-related epidemiological studies.

  6. Development of mathematical pediatric phantoms for internal dose calculations: designs, limitations, and prospects

    SciTech Connect

    Cristy, M.

    1980-01-01

    Mathematical phantoms of the human body at various ages are employed with Monte Carlo radiation transport codes for calculation of photon specific absorbed fractions. The author has developed a pediatric phantom series based on the design of the adult phantom, but with explicit equations for each organ so that organ sizes and marrow distributions could be assigned properly. Since the phantoms comprise simple geometric shapes, predictive dose capability is limited when geometry is critical to the calculation. Hence, there is a demand for better phantom design in situations where geometry is critical, such as for external irradiation or for internal emitters with low energy photons. Recent advances in computerized axial tomography (CAT) present the potential for derivation of anatomical information, which is so critical to development of phantoms, and ongoing developmental work on compuer architecture to handle large arrays for Monte Carlo calculations should make complex-geometry dose calculations economically feasible within this decade.

  7. NASA astronaut dosimetry: Implementation of scalable human phantoms and benchmark comparisons of deterministic versus Monte Carlo radiation transport

    NASA Astrophysics Data System (ADS)

    Bahadori, Amir Alexander

    Astronauts are exposed to a unique radiation environment in space. United States terrestrial radiation worker limits, derived from guidelines produced by scientific panels, do not apply to astronauts. Limits for astronauts have changed throughout the Space Age, eventually reaching the current National Aeronautics and Space Administration limit of 3% risk of exposure induced death, with an administrative stipulation that the risk be assured to the upper 95% confidence limit. Much effort has been spent on reducing the uncertainty associated with evaluating astronaut risk for radiogenic cancer mortality, while tools that affect the accuracy of the calculations have largely remained unchanged. In the present study, the impacts of using more realistic computational phantoms with size variability to represent astronauts with simplified deterministic radiation transport were evaluated. Next, the impacts of microgravity-induced body changes on space radiation dosimetry using the same transport method were investigated. Finally, dosimetry and risk calculations resulting from Monte Carlo radiation transport were compared with results obtained using simplified deterministic radiation transport. The results of the present study indicated that the use of phantoms that more accurately represent human anatomy can substantially improve space radiation dose estimates, most notably for exposures from solar particle events under light shielding conditions. Microgravity-induced changes were less important, but results showed that flexible phantoms could assist in optimizing astronaut body position for reducing exposures during solar particle events. Finally, little overall differences in risk calculations using simplified deterministic radiation transport and 3D Monte Carlo radiation transport were found; however, for the galactic cosmic ray ion spectra, compensating errors were observed for the constituent ions, thus exhibiting the need to perform evaluations on a particle

  8. Tomographic measurement of temperature change in phantoms of the human body by chirp radar-type microwave computed tomography.

    PubMed

    Miyakawa, M

    1993-07-01

    The chirp radar-type microwave computed tomograph (CT) measures the temperature change in a human body noninvasively. The paper examines its feasibility. A chirp pulse signal between 1 and 2 GHz is radiated from the transmitting antenna to the phantom. The transmitted waves are detected by the receiving antenna, which is placed on the opposite side of the object, and the beat signal between the incident wave and the transmitted wave is produced by the mixer. By spectral analysis of the beat signal, only those signals transmitted on the straight line between the transmitting antenna and the receiving antenna are discriminated from multipath signals. The microwave tomogram can therefore be reconstructed easily using the conventional algorithms for an X-ray CT image. The microwave CT can use the chirp signal to remove the influence of multipath signals caused by diffraction and reflection. The imaging of dielectric materials with complicated structures is thus possible. The experimental results using phantoms show that the spatial resolution of this microwave CT is about 10 mm and that a two-dimensional distribution of temperature change can be measured.

  9. [Theoretical and Experimental Dosimetry in Evaluation of Biological Effects of Electromagnetic Field for Portable Radio Transmitters. Report 2. Homogeneous Human Head Phantom].

    PubMed

    Perov, S Yu; Bogacheva, E V

    2015-01-01

    Results of theoretical (numerical) and experimental electromagnetic field dosimetry for homogeneous human head phantoms are considered. The simulation and measurement results are shown. This paper presents the results of Specific Absorption Rate (SAR) evaluation in the "special anthropomorphic model" of human head, when a source of electromagnetic radio frequency field is placed in front of the face. The minimal difference is shown between measurements and simulation results in Head Simulating Liquid, which makes it possible to conduct further brain tissue simulations. The investigations show that the type of electromagnetic field source and phantom form play an important part for SAR distribution. PMID:26601543

  10. [Theoretical and Experimental Dosimetry in Evaluation of Biological Effects of Electromagnetic Field for Portable Radio Transmitters. Report 2. Homogeneous Human Head Phantom].

    PubMed

    Perov, S Yu; Bogacheva, E V

    2015-01-01

    Results of theoretical (numerical) and experimental electromagnetic field dosimetry for homogeneous human head phantoms are considered. The simulation and measurement results are shown. This paper presents the results of Specific Absorption Rate (SAR) evaluation in the "special anthropomorphic model" of human head, when a source of electromagnetic radio frequency field is placed in front of the face. The minimal difference is shown between measurements and simulation results in Head Simulating Liquid, which makes it possible to conduct further brain tissue simulations. The investigations show that the type of electromagnetic field source and phantom form play an important part for SAR distribution.

  11. Dosimetry of a cone beam CT device for oral and maxillofacial radiology using Monte Carlo techniques and ICRP adult reference computational phantoms

    PubMed Central

    Morant, JJ; Salvadó, M; Hernández-Girón, I; Casanovas, R; Ortega, R; Calzado, A

    2013-01-01

    Objectives: The aim of this study was to calculate organ and effective doses for a range of available protocols in a particular cone beam CT (CBCT) scanner dedicated to dentistry and to derive effective dose conversion factors. Methods: Monte Carlo simulations were used to calculate organ and effective doses using the International Commission on Radiological Protection voxel adult male and female reference phantoms (AM and AF) in an i-CAT CBCT. Nine different fields of view (FOVs) were simulated considering full- and half-rotation modes, and also a high-resolution acquisition for a particular protocol. Dose–area product (DAP) was measured. Results: Dose to organs varied for the different FOVs, usually being higher in the AF phantom. For 360°, effective doses were in the range of 25–66 μSv, and 46 μSv for full head. Higher contributions to the effective dose corresponded to the remainder (31%; 27–36 range), salivary glands (23%; 20–29%), thyroid (13%; 8–17%), red bone marrow (10%; 9–11%) and oesophagus (7%; 4–10%). The high-resolution protocol doubled the standard resolution doses. DAP values were between 181 mGy cm2 and 556 mGy cm2 for 360°. For 180° protocols, dose to organs, effective dose and DAP were approximately 40% lower. A conversion factor (DAP to effective dose) of 0.130 ± 0.006 μSv mGy−1 cm−2 was derived for all the protocols, excluding full head. A wide variation in dose to eye lens and thyroid was found when shifting the FOV in the AF phantom. Conclusions: Organ and effective doses varied according to field size, acquisition angle and positioning of the beam relative to radiosensitive organs. Good positive correlation between calculated effective dose and measured DAP was found. PMID:22933532

  12. Evaluation of organ doses and specific k effective dose of 64-slice CT thorax examination using an adult anthropomorphic phantom

    NASA Astrophysics Data System (ADS)

    Hashim, S.; Karim, M. K. A.; Bakar, K. A.; Sabarudin, A.; Chin, A. W.; Saripan, M. I.; Bradley, D. A.

    2016-09-01

    The magnitude of radiation dose in computed tomography (CT) depends on the scan acquisition parameters, investigated herein using an anthropomorphic phantom (RANDO®) and thermoluminescence dosimeters (TLD). Specific interest was in the organ doses resulting from CT thorax examination, the specific k coefficient for effective dose estimation for particular protocols also being determined. For measurement of doses representing five main organs (thyroid, lung, liver, esophagus and skin), TLD-100 (LiF:Mg, Ti) were inserted into selected holes in a phantom slab. Five CT thorax protocols were investigated, one routine (R1) and four that were modified protocols (R2 to R5). Organ doses were ranked from greatest to least, found to lie in the order: thyroid>skin>lung>liver>breast. The greatest dose, for thyroid at 25 mGy, was that in use of R1 while the lowest, at 8.8 mGy, was in breast tissue using R3. Effective dose (E) was estimated using three standard methods: the International Commission on Radiological Protection (ICRP)-103 recommendation (E103), the computational phantom CT-EXPO (E(CTEXPO)) method, and the dose-length product (DLP) based approach. E103 k factors were constant for all protocols, ~8% less than that of the universal k factor. Due to inconsistency in tube potential and pitch factor the k factors from CTEXPO were found to vary between 0.015 and 0.010 for protocols R3 and R5. With considerable variation between scan acquisition parameters and organ doses, optimization of practice is necessary in order to reduce patient organ dose.

  13. Angiogenic properties of adult human thymus fat.

    PubMed

    Salas, Julián; Montiel, Mercedes; Jiménez, Eugenio; Valenzuela, Miguel; Valderrama, José Francisco; Castillo, Rafael; González, Sergio; El Bekay, Rajaa

    2009-11-01

    The endogenous proangiogenic properties of adipose tissue are well recognized. Although the adult human thymus has long been known to degenerate into fat tissue, it has never been considered as a potential source of angiogenic factors. We have investigated the expression of diverse angiogenic factors, including vascular endothelial growth factor A and B, angiopoietin 1, and tyrosine-protein kinase receptor-2 (an angiopoietin receptor), and then analyzed their physiological role on endothelial cell migration and proliferation, two relevant events in angiogenesis. The detection of the gene and protein expression of the various proteins has been performed by immunohistochemistry, Western blotting, and quantitative real-time polymerase chain reaction. We show, for the first time, that adult thymus fat produces a variety of angiogenic factors and induces the proliferation and migration of human umbilical cord endothelial cells. Based on these findings, we suggest that this fat has a potential angiogenic function that might affect thymic function and ongoing adipogenesis within the thymus.

  14. Analysis of mobile phone design features affecting radiofrequency power absorbed in a human head phantom.

    PubMed

    Kuehn, Sven; Kelsh, Michael A; Kuster, Niels; Sheppard, Asher R; Shum, Mona

    2013-09-01

    The US FCC mandates the testing of all mobile phones to demonstrate compliance with the rule requiring that the peak spatial SAR does not exceed the limit of 1.6 W/kg averaged over any 1 g of tissue. These test data, measured in phantoms with mobile phones operating at maximum antenna input power, permitted us to evaluate the variation in SARs across mobile phone design factors such as shape and antenna design, communication technology, and test date (over a 7-year period). Descriptive statistical summaries calculated for 850 MHz and 1900 MHz phones and ANOVA were used to evaluate the influence of the foregoing factors on SARs. Service technology accounted for the greatest variability in compliance test SARs that ranged from AMPS (highest) to CDMA, iDEN, TDMA, and GSM (lowest). However, the dominant factor for SARs during use is the time-averaged antenna input power, which may be much less than the maximum power used in testing. This factor is largely defined by the communication system; e.g., the GSM phone average output can be higher than CDMA by a factor of 100. Phone shape, antenna type, and orientation of a phone were found to be significant but only on the order of up to a factor of 2 (3 dB). The SAR in the tilt position was significantly smaller than for touch. The side of the head did not affect SAR levels significantly. Among the remaining factors, external antennae produced greater SARs than internal ones, and brick and clamshell phones produced greater SARs than slide phones. Assuming phone design and usage patterns do not change significantly over time, we have developed a normalization procedure and formula that permits reliable prediction of the relative SAR between various communication systems. This approach can be applied to improve exposure assessment in epidemiological research.

  15. Phantom validation for ultrasound to statistical shape model registration of human pelvis

    NASA Astrophysics Data System (ADS)

    Ghanavati, Sahar; Mousavi, Parvin; Fichtinger, Gabor; Abolmaesumi, Purang

    2011-03-01

    Total Hip Replacement (THR) has become a common surgical procedure in recent years, as a result of increasing aging population with osteoarthritis of the hip joint. Localization of the pelvic anatomical coordinate system (PaCS) is a critical step in accurate placement of the femur prosthesis in the acetabulum in THR. Intra-operative ultrasound (US) imaging can provide a radiation-free navigation system for localization of the PaCS. However, US images are noisy and cannot provide any anatomical information beneath the bone surface due to the total reflection of US beam at the bone-soft tissue interface. A solution to this problem is to fuse intra-operative US with pre-operative imaging or a statistical shape model (SSM) of the pelvis. Here, we propose a multi-slice to volume intensity-based registration of the pelvic SSM to a sparse set of 2D US images in order to localize the PaCS in the US. In this registration technique, a set of 2D slices are extracted from a pelvic SSM using the approximate location and orientation of their corresponding 2D US images. During the registration, the comparison between the SSM slices and the US images is made using an ultrasound simulation technique and a correlation-based similarity metric. We demonstrate the feasibility of our proposed approach in localizing the PaCS on five patient-based phantoms. These results indicate the necessity of including pubic symphysis landmarks in the 2D US slices in order to have a precise estimation of the PaCS.

  16. Thiamin requirement of the adult human.

    PubMed

    Sauberlich, H E; Herman, Y F; Stevens, C O; Herman, R H

    1979-11-01

    Young adult male subjects maintained on a metabolic ward were fed diets providing controlled intakes of thiamin and either 2800 or 3600 kcal. The higher level of calories was attained by an increased intake of carbohydrates. Constant weights were maintained by the subjects by adjusting daily activity and exercise schedules. Thiamin requirements were evaluated in terms of erythrocyte transketolase activity and urinary excretion of the vitamin. The results of the study revealed that a relationship exists between thiamin requirement and caloric intake and expenditure. Thus, when the calories being utilized were derived primarily from carbohydrate sources, the minimum adult male requirement for thiamin appeared to be 0.30 mg of thiamin per 1000 kcal. Urinary excretion of thiamin and erythrocyte transketolase activity appear to be reasonably reliable reflections of thiamin intakes and thiamin nutritional status. The use of these measurements in nutrition surveys appears justified. The microbiological assay (Lactobacillus viridescens) for measuring thiamin levels in urine samples appears to be a somewhat more sensitive but valid procedure as an alternate for the thiochrome method. Judged from the results of this study, the recommended intake for the adult human of 0.40 mg of thiamin per 1000 kcal by FAO/WHO and the recommended allowance of 0.5 mg per 1000 kcal by the Food and Nutrition Board of the NAS-NRC appear reasonable and amply allow for biological variations and other factors that may influence the requirement for this vitamin.

  17. Infant phantom head circuit board for EEG head phantom and pediatric brain simulation

    NASA Astrophysics Data System (ADS)

    Almohsen, Safa

    The infant's skull differs from an adult skull because of the characteristic features of the human skull during early development. The fontanels and the conductivity of the infant skull influence surface currents, generated by neurons, which underlie electroencephalography (EEG) signals. An electric circuit was built to power a set of simulated neural sources for an infant brain activity simulator. Also, in the simulator, three phantom tissues were created using saline solution plus Agarose gel to mimic the conductivity of each layer in the head [scalp, skull brain]. The conductivity measurement was accomplished by two different techniques: using the four points' measurement technique, and a conductivity meter. Test results showed that the optimized phantom tissues had appropriate conductivities to simulate each tissue layer to fabricate a physical head phantom. In this case, the best results should be achieved by testing the electrical neural circuit with the sample physical model to generate simulated EEG data and use that to solve both the forward and the inverse problems for the purpose of localizing the neural sources in the head phantom.

  18. Development of 5- and 10-year-old pediatric phantoms based on polygon mesh surfaces

    SciTech Connect

    Melo Lima, V. J. de; Cassola, V. F.; Kramer, R.; Oliveira Lira, C. A. B. de; Khoury, H. J.; Vieira, J. W.

    2011-08-15

    Purpose: The purpose of this study is the development of reference pediatric phantoms for 5- and 10-year-old children to be used for the calculation of organ and tissue equivalent doses in radiation protection. Methods: The study proposes a method for developing anatomically highly sophisticated pediatric phantoms without using medical images. The 5- and 10-year-old male and female phantoms presented here were developed using 3D modeling software applied to anatomical information taken from atlases and textbooks. The method uses polygon mesh surfaces to model body contours, the shape of organs as well as their positions, and orientations in the human body. Organ and tissue masses comply with the corresponding data given by the International Commission on Radiological Protection (ICRP) for the 5- and 10-year-old reference children. Bones were segmented into cortical bone, spongiosa, medullary marrow, and cartilage to allow for the use of micro computer tomographic ({mu}CT) images of trabecular bone for skeletal dosimetry. Results: The four phantoms, a male and a female for each age, and their organs are presented in 3D images and their organ and tissue masses in tables which show the compliance of the ICRP reference values. Dosimetric data, calculated for the reference pediatric phantoms by Monte Carlo methods were compared with corresponding data from adult mesh phantoms and pediatric stylized phantoms. The comparisons show reasonable agreement if the anatomical differences between the phantoms are properly taken into account. Conclusions: Pediatric phantoms were developed without using medical images of patients or volunteers for the first time. The models are reference phantoms, suitable for regulatory dosimetry, however, the 3D modeling method can also be applied to medical images to develop patient-specific phantoms.

  19. NOTE: Spectra from 2.5-15 µm of tissue phantom materials, optical clearing agents and ex vivo human skin: implications for depth profiling of human skin

    NASA Astrophysics Data System (ADS)

    Viator, John A.; Choi, Bernard; Peavy, George M.; Kimel, Sol; Nelson, J. Stuart

    2003-01-01

    Infrared measurements have been used to profile or image biological tissue, including human skin. Usually, analysis of such measurements has assumed that infrared absorption is due to water and collagen. Such an assumption may be reasonable for soft tissue, but introduction of exogenous agents into skin or the measurement of tissue phantoms has raised the question of their infrared absorption spectrum. We used Fourier transform infrared spectroscopy in attenuated total reflection mode to measure the infrared absorption spectra, in the range of 2-15 µm, of water, polyacrylamide, Intralipid, collagen gels, four hyperosmotic clearing agents (glycerol, 1,3-butylene glycol, trimethylolpropane, TopicareTM), and ex vivo human stratum corneum and dermis. The absorption spectra of the phantom materials were similar to that of water, although additional structure was noted in the range of 6-10 µm. The absorption spectra of the clearing agents were more complex, with molecular absorption bands dominating between 6 and 12 µm. Dermis was similar to water, with collagen structure evident in the 6-10 µm range. Stratum corneum had a significantly lower absorption than dermis due to a lower content of water. These results suggest that the assumption of water-dominated absorption in the 2.5-6 µm range is valid. At longer wavelengths, clearing agent absorption spectra differ significantly from the water spectrum. This spectral information can be used in pulsed photothermal radiometry or utilized in the interpretation of reconstructions in which a constant μir is used. In such cases, overestimating μir will underestimate chromophore depth and vice versa, although the effect is dependent on actual chromophore depth.

  20. The neutron dose conversion coefficients calculation in human tooth enamel in an anthropomorphic phantom.

    PubMed

    Khailov, A M; Ivannikov, A I; Skvortsov, V G; Stepanenko, V F; Tsyb, A F; Trompier, F; Hoshi, M

    2010-02-01

    In the present study, MCNP4B simulation code is used to simulate neutron and photon transport. It gives the conversion coefficients that relate neutron fluence to the dose in tooth enamel (molars and pre-molars only) for 20 energy groups of monoenergetic neutrons with energies from 10-9 to 20 MeV for five different irradiation geometries. The data presented are intended to provide the basis for connection between EPR dose values and standard protection quantities defined in ICRP Publication 74. The results of the calculations for critical organs were found to be consistent with ICRP data, with discrepancies generally less than 10% for the fast neutrons. The absorbed dose in enamel was found to depend strongly on the incident neutron energy for neutrons over 10 keV. The dependence of the data on the irradiation geometry is also shown. Lower bound estimates of enamel radiation sensitivity to neutrons were made using obtained coefficients for the secondary photons. Depending on neutron energy, tooth enamel was shown to register 10-120% of the total neutron dose in the human body in the case of pure neutron exposure and AP irradiation geometry. PMID:20065707

  1. Fluence-to-dose conversion coefficients for heavy ions calculated using the PHITS code and the ICRP/ICRU adult reference computational phantoms

    NASA Astrophysics Data System (ADS)

    Sato, Tatsuhiko; Endo, Akira; Niita, Koji

    2010-04-01

    The fluence to organ-absorbed-dose and effective-dose conversion coefficients for heavy ions with atomic numbers up to 28 and energies from 1 MeV/nucleon to 100 GeV/nucleon were calculated using the PHITS code coupled to the ICRP/ICRU adult reference computational phantoms, following the instruction given in ICRP Publication 103 (2007 (Oxford: Pergamon)). The conversion coefficients for effective dose equivalents derived using the radiation quality factors of both Q(L) and Q(y) relationships were also estimated, utilizing the functions for calculating the probability densities of absorbed dose in terms of LET (L) and lineal energy (y), respectively, implemented in PHITS. The calculation results indicate that the effective dose can generally give a conservative estimation of the effective dose equivalent for heavy-ion exposure, although it is occasionally too conservative especially for high-energy lighter-ion irradiations. It is also found from the calculation that the conversion coefficients for the Q(y)-based effective dose equivalents are generally smaller than the corresponding Q(L)-based values because of the conceptual difference between LET and y as well as the numerical incompatibility between the Q(L) and Q(y) relationships. The calculated data of these dose conversion coefficients are very useful for the dose estimation of astronauts due to cosmic-ray exposure.

  2. Fluence-to-dose conversion coefficients for heavy ions calculated using the PHITS code and the ICRP/ICRU adult reference computational phantoms.

    PubMed

    Sato, Tatsuhiko; Endo, Akira; Niita, Koji

    2010-04-21

    The fluence to organ-absorbed-dose and effective-dose conversion coefficients for heavy ions with atomic numbers up to 28 and energies from 1 MeV/nucleon to 100 GeV/nucleon were calculated using the PHITS code coupled to the ICRP/ICRU adult reference computational phantoms, following the instruction given in ICRP Publication 103 (2007 (Oxford: Pergamon)). The conversion coefficients for effective dose equivalents derived using the radiation quality factors of both Q(L) and Q(y) relationships were also estimated, utilizing the functions for calculating the probability densities of absorbed dose in terms of LET (L) and lineal energy (y), respectively, implemented in PHITS. The calculation results indicate that the effective dose can generally give a conservative estimation of the effective dose equivalent for heavy-ion exposure, although it is occasionally too conservative especially for high-energy lighter-ion irradiations. It is also found from the calculation that the conversion coefficients for the Q(y)-based effective dose equivalents are generally smaller than the corresponding Q(L)-based values because of the conceptual difference between LET and y as well as the numerical incompatibility between the Q(L) and Q(y) relationships. The calculated data of these dose conversion coefficients are very useful for the dose estimation of astronauts due to cosmic-ray exposure. PMID:20354281

  3. Dose estimation for astronauts using dose conversion coefficients calculated with the PHITS code and the ICRP/ICRU adult reference computational phantoms.

    PubMed

    Sato, Tatsuhiko; Endo, Akira; Sihver, Lembit; Niita, Koji

    2011-03-01

    Absorbed-dose and dose-equivalent rates for astronauts were estimated by multiplying fluence-to-dose conversion coefficients in the units of Gy.cm(2) and Sv.cm(2), respectively, and cosmic-ray fluxes around spacecrafts in the unit of cm(-2) s(-1). The dose conversion coefficients employed in the calculation were evaluated using the general-purpose particle and heavy ion transport code system PHITS coupled to the male and female adult reference computational phantoms, which were released as a common ICRP/ICRU publication. The cosmic-ray fluxes inside and near to spacecrafts were also calculated by PHITS, using simplified geometries. The accuracy of the obtained absorbed-dose and dose-equivalent rates was verified by various experimental data measured both inside and outside spacecrafts. The calculations quantitatively show that the effective doses for astronauts are significantly greater than their corresponding effective dose equivalents, because of the numerical incompatibility between the radiation quality factors and the radiation weighting factors. These results demonstrate the usefulness of dose conversion coefficients in space dosimetry. PMID:20835833

  4. Fluence-to-dose conversion coefficients for neutrons and protons calculated using the PHITS code and ICRP/ICRU adult reference computational phantoms.

    PubMed

    Sato, Tatsuhiko; Endo, Akira; Zankl, Maria; Petoussi-Henss, Nina; Niita, Koji

    2009-04-01

    The fluence to organ-dose and effective-dose conversion coefficients for neutrons and protons with energies up to 100 GeV was calculated using the PHITS code coupled to male and female adult reference computational phantoms, which are to be released as a common ICRP/ICRU publication. For the calculation, the radiation and tissue weighting factors, w(R) and w(T), respectively, as revised in ICRP Publication 103 were employed. The conversion coefficients for effective dose equivalents derived using the radiation quality factors of both Q(L) and Q(y) relationships were also estimated, utilizing the functions for calculating the probability densities of the absorbed dose in terms of LET (L) and lineal energy (y), respectively, implemented in PHITS. By comparing these data with the corresponding data for the effective dose, we found that the numerical compatibilities of the revised w(R) with the Q(L) and Q(y) relationships are fairly established. The calculated data of these dose conversion coefficients are indispensable for constructing the radiation protection systems based on the new recommendations given in ICRP103 for aircrews and astronauts, as well as for workers in accelerators and nuclear facilities.

  5. Dose estimation for astronauts using dose conversion coefficients calculated with the PHITS code and the ICRP/ICRU adult reference computational phantoms.

    PubMed

    Sato, Tatsuhiko; Endo, Akira; Sihver, Lembit; Niita, Koji

    2011-03-01

    Absorbed-dose and dose-equivalent rates for astronauts were estimated by multiplying fluence-to-dose conversion coefficients in the units of Gy.cm(2) and Sv.cm(2), respectively, and cosmic-ray fluxes around spacecrafts in the unit of cm(-2) s(-1). The dose conversion coefficients employed in the calculation were evaluated using the general-purpose particle and heavy ion transport code system PHITS coupled to the male and female adult reference computational phantoms, which were released as a common ICRP/ICRU publication. The cosmic-ray fluxes inside and near to spacecrafts were also calculated by PHITS, using simplified geometries. The accuracy of the obtained absorbed-dose and dose-equivalent rates was verified by various experimental data measured both inside and outside spacecrafts. The calculations quantitatively show that the effective doses for astronauts are significantly greater than their corresponding effective dose equivalents, because of the numerical incompatibility between the radiation quality factors and the radiation weighting factors. These results demonstrate the usefulness of dose conversion coefficients in space dosimetry.

  6. Rethinking Adult Literacy Programs: A Humanities-Based Curriculum.

    ERIC Educational Resources Information Center

    Anania, Joanne

    The Roosevelt University Humanities Enrichment Program tries to acknowledge the adult part of adult literacy. Its instructional materials are of interest and value to the adult student and, therefore, provide incentives for reading and discussion instead of serving merely as skill-building exercises. The materials are drawn from literature,…

  7. Comparison of Organ Dose and Dose Equivalent Using Ray Tracing of Male and Female Voxel Phantoms to Space Flight Phantom Torso Data

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee Y.; Qualls, Garry D.; Cucinotta, Francis A.

    2008-01-01

    Phantom torso experiments have been flown on the space shuttle and International Space Station (ISS) providing validation data for radiation transport models of organ dose and dose equivalents. We describe results for space radiation organ doses using a new human geometry model based on detailed Voxel phantoms models denoted for males and females as MAX (Male Adult voXel) and Fax (Female Adult voXel), respectively. These models represent the human body with much higher fidelity than the CAMERA model currently used at NASA. The MAX and FAX models were implemented for the evaluation of directional body shielding mass for over 1500 target points of major organs. Radiation exposure to solar particle events (SPE), trapped protons, and galactic cosmic rays (GCR) were assessed at each specific site in the human body by coupling space radiation transport models with the detailed body shielding mass of MAX/FAX phantom. The development of multiple-point body-shielding distributions at each organ site made it possible to estimate the mean and variance of space dose equivalents at the specific organ. For the estimate of doses to the blood forming organs (BFOs), active marrow distributions in adult were accounted at bone marrow sites over the human body. We compared the current model results to space shuttle and ISS phantom torso experiments and to calculations using the CAMERA model.

  8. Comparison of organ dose and dose equivalent using ray tracing of male and female Voxel phantoms to space flight phantom torso data

    NASA Astrophysics Data System (ADS)

    Kim, Myung-Hee; Qualls, Garry; Slaba, Tony; Cucinotta, Francis A.

    Phantom torso experiments have been flown on the space shuttle and International Space Station (ISS) providing validation data for radiation transport models of organ dose and dose equivalents. We describe results for space radiation organ doses using a new human geometry model based on detailed Voxel phantoms models denoted for males and females as MAX (Male Adult voXel) and Fax (Female Adult voXel), respectively. These models represent the human body with much higher fidelity than the CAMERA model currently used at NASA. The MAX and FAX models were implemented for the evaluation of directional body shielding mass for over 1500 target points of major organs. Radiation exposure to solar particle events (SPE), trapped protons, and galactic cosmic rays (GCR) were assessed at each specific site in the human body by coupling space radiation transport models with the detailed body shielding mass of MAX/FAX phantom. The development of multiple-point body-shielding distributions at each organ site made it possible to estimate the mean and variance of space dose equivalents at the specific organ. For the estimate of doses to the blood forming organs (BFOs), active marrow distributions in adult were accounted at bone marrow sites over the human body. We compared the current model results to space shuttle and ISS phantom torso experiments and to calculations using the CAMERA model.

  9. The ESA-Facility MATROSHKA: A human phantom for dose measurements occurring in men being exposed during an Extra Vehicular Activity (EVA).

    NASA Astrophysics Data System (ADS)

    Reitz, G.

    The Matroshka facility basically consists of the upper part of a body phantom, com- posed of various tissue substitutes simulating the human body with respect to size, shape, position, mass density and nuclear interactions. At the site of the organs of interest, spaces are provided at the surface and in different depths inside the phan- tom to accommodate active and passive dosimeter packages for measurements of any radiation type. The phantom is mounted on a base structure containing the facility electronics and surrounded by a Carbon Fiber container providing structural support and fixation of the phantom and providing shielding thickness comparable to the EVA suit. The container and the base structure build up a sealed compartment. The objective of the proposed facility is to determine the empirical relations between measurable absorbed doses and the required tissue absorbed doses in a realistic hu- man phantom exposed to the concrete radiation field to be monitored. The radiation field during extravehicular activities (EVA) is that of the free space environment mod- ified only by the space suit. Since EVAs will form a substantial fraction of the work- schedule in the space station scenario, such measurements have highest priority. Once the ratios for the tissue absorbed doses and surface absorbed doses are known for a given radiation field around the human body, these values may be used in future expo- sures to determine the required tissue absorbed doses from measurements of surface absorbed doses, only. This technical presentation will describe the design of the MATROSHKA facility which is expected to be launched late 2003.

  10. Have you got any cholesterol? Adults' views of human nutrition

    NASA Astrophysics Data System (ADS)

    Schibeci, Renato; Wong, Khoon Yoong

    1994-12-01

    The general aim of our human nutrition project is to develop a health education model grounded in ‘everyday’ or ‘situated’ cognition (Hennessey, 1993). In 1993, we began pilot work to document adult understanding of human nutrition. We used a HyperCard stack as the basis for a series of interviews with 50 adults (25 university students, and 25 adults from offcampus). The interviews were transcribed and analysed using the NUDIST computer program. A summary of the views of these 50 adults on selected aspects of human nutrition is presented in this paper.

  11. Adult Education & Human Resource Development: Overlapping and Disparate Fields

    ERIC Educational Resources Information Center

    Watkins, Karen E.; Marsick, Victoria J.

    2014-01-01

    Adult education and human resource development as fields of practice and study share some roots in common but have grown in different directions in their histories. Adult education's roots focused initially on citizenship for a democratic society, whereas human resource development's roots are in performance at work. While they have…

  12. Could adult hippocampal neurogenesis be relevant for human behavior?

    PubMed Central

    Snyder, Jason S.; Cameron, Heather A.

    2011-01-01

    Although the function of adult neurogenesis is still unclear, tools for directly studying the behavioral role of new hippocampal neurons now exist in rodents. Since similar studies are impossible to do in humans, it is important to assess whether the role of new neurons in rodents is likely to be similar to that in humans. One feature of adult neurogenesis that varies tremendously across species is the number of neurons that are generated, so a key question is whether there are enough neurons generated in humans to impact function. In this review we examine neuroanatomy and circuit function in the hippocampus to ask how many granule neurons are needed to impact hippocampal function and then discuss what is known about numbers of new neurons produced in adult rats and humans. We conclude that relatively small numbers of neurons could affect hippocampal circuits and that the magnitude of adult neurogenesis in adult rats and humans is probably larger than generally believed. PMID:21736900

  13. Motion compensation for brain PET imaging using wireless MR active markers in simultaneous PET-MR: phantom and non-human primate studies

    PubMed Central

    Huang, Chuan; Ackerman, Jerome L.; Petibon, Yoann; Normandin, Marc D.; Brady, Thomas J.; El Fakhri, Georges; Ouyang, Jinsong

    2014-01-01

    Brain PET scanning plays an important role in the diagnosis, prognostication and monitoring of many brain diseases. Motion artifacts from head motion are one of the major hurdles in brain PET. In this work, we propose to use wireless MR active markers to track head motion in real time during a simultaneous PET-MR brain scan and incorporate the motion measured by the markers in the listmode PET reconstruction. Several wireless MR active markers and a dedicated fast MR tracking pulse sequence module were built. Data were acquired on an ACR Flangeless PET phantom with multiple spheres and a non-human primate with and without motion. Motions of the phantom and monkey’s head were measured with the wireless markers using a dedicated MR tracking sequence module. The motion PET data were reconstructed using list-mode reconstruction with and without motion correction. Static reference was used as gold standard for quantitative analysis. The motion artifacts, which were prominent on the images without motion correction, were eliminated by the wireless marker based motion correction in both the phantom and monkey experiments. Quantitative analysis was performed on the phantom motion data from 24 independent noise realizations. The reduction of bias of sphere-to-background PET contrast by active marker based motion correction ranges from 26% to 64% and 17% to 25% for hot (i.e., radioactive) and cold (i.e., non-radioactive) spheres, respectively. The motion correction improved the channelized Hotelling observer signal-to-noise ratio of the spheres by 1.2 to 6.9 depending on their locations and sizes. The proposed wireless MR active marker based motion correction technique removes the motion artifacts in the reconstructed PET images and yields accurate quantitative values. PMID:24418501

  14. Motion compensation for brain PET imaging using wireless MR active markers in simultaneous PET-MR: phantom and non-human primate studies.

    PubMed

    Huang, Chuan; Ackerman, Jerome L; Petibon, Yoann; Normandin, Marc D; Brady, Thomas J; El Fakhri, Georges; Ouyang, Jinsong

    2014-05-01

    Brain PET scanning plays an important role in the diagnosis, prognostication and monitoring of many brain diseases. Motion artifacts from head motion are one of the major hurdles in brain PET. In this work, we propose to use wireless MR active markers to track head motion in real time during a simultaneous PET-MR brain scan and incorporate the motion measured by the markers in the listmode PET reconstruction. Several wireless MR active markers and a dedicated fast MR tracking pulse sequence module were built. Data were acquired on an ACR Flangeless PET phantom with multiple spheres and a non-human primate with and without motion. Motions of the phantom and monkey's head were measured with the wireless markers using a dedicated MR tracking sequence module. The motion PET data were reconstructed using list-mode reconstruction with and without motion correction. Static reference was used as gold standard for quantitative analysis. The motion artifacts, which were prominent on the images without motion correction, were eliminated by the wireless marker based motion correction in both the phantom and monkey experiments. Quantitative analysis was performed on the phantom motion data from 24 independent noise realizations. The reduction of bias of sphere-to-background PET contrast by active marker based motion correction ranges from 26% to 64% and 17% to 25% for hot (i.e., radioactive) and cold (i.e., non-radioactive) spheres, respectively. The motion correction improved the channelized Hotelling observer signal-to-noise ratio of the spheres by 1.2 to 6.9 depending on their locations and sizes. The proposed wireless MR active marker based motion correction technique removes the motion artifacts in the reconstructed PET images and yields accurate quantitative values.

  15. Phytoestrogen Metabolism by Adult Human Gut Microbiota.

    PubMed

    Gaya, Pilar; Medina, Margarita; Sánchez-Jiménez, Abel; Landete, José Mᵃ

    2016-08-09

    Phytoestrogens are plant-derived polyphenols with a structure similar to human estrogens. The three main groups of phytoestrogens, isoflavones, ellagitannins, and lignans, are transformed into equol, urolithins, and enterolignans, respectively, by bacteria. These metabolites have more estrogenic/antiestrogenic and antioxidant activities than their precursors, and they are more bioavailable. The aim of this study was to analyze the metabolism of isoflavones, lignans and ellagitannins by gut microbiota, and to study the possible correlation in the metabolism of these three groups of phytoestrogens. In vitro fermentation experiments were performed with feces samples from 14 healthy adult volunteers, and metabolite formation was measured by HPLC-PAD and HPLC-ESI/MS. Only the microbiota of one subject produced equol, while most of them showed production of O-desmethylangolensin (O-DMA). Significant inter-subject differences were observed in the metabolism of dihydrodaidzein and dihydrogenistein, while the glucoside isoflavones and their aglycones showed less variability, except for glycitin. Most subjects produced urolithins M-5 and E. Urolithin D was not detected, while uroltithin B was found in half of the individuals analyzed, and urolithins A and C were detected in two and four subjects, respectively. Enterolactone was found in all subjects, while enterodiol only appeared in five. Isoflavone metabolism could be correlated with the metabolism of lignans and ellagitannins. However, the metabolism of ellagitannins and lignans could not be correlated. This the first study where the metabolism of the three groups together of phytoestrogen, isoflavones, lignans, and ellagitannins by gut microbiota is analyzed.

  16. The perception of phantom limbs. The D. O. Hebb lecture.

    PubMed

    Ramachandran, V S; Hirstein, W

    1998-09-01

    Almost everyone who has a limb amputated will experience a phantom limb--the vivid impression that the limb is not only still present, but in some cases, painful. There is now a wealth of empirical evidence demonstrating changes in cortical topography in primates following deafferentation or amputation, and this review will attempt to relate these in a systematic way to the clinical phenomenology of phantom limbs. With the advent of non-invasive imaging techniques such as MEG (magnetoencephalogram) and functional MRI, topographical reorganization can also be demonstrated in humans, so that it is now possible to track perceptual changes and changes in cortical topography in individual patients. We suggest, therefore, that these patients provide a valuable opportunity not only for exploring neural plasticity in the adult human brain but also for understanding the relationship between the activity of sensory neurons and conscious experience. We conclude with a theory of phantom limbs, some striking demonstrations of phantoms induced in normal subjects, and some remarks about the relevance of these phenomena to the question of how the brain constructs a 'body image.'

  17. The perception of phantom limbs. The D. O. Hebb lecture.

    PubMed

    Ramachandran, V S; Hirstein, W

    1998-09-01

    Almost everyone who has a limb amputated will experience a phantom limb--the vivid impression that the limb is not only still present, but in some cases, painful. There is now a wealth of empirical evidence demonstrating changes in cortical topography in primates following deafferentation or amputation, and this review will attempt to relate these in a systematic way to the clinical phenomenology of phantom limbs. With the advent of non-invasive imaging techniques such as MEG (magnetoencephalogram) and functional MRI, topographical reorganization can also be demonstrated in humans, so that it is now possible to track perceptual changes and changes in cortical topography in individual patients. We suggest, therefore, that these patients provide a valuable opportunity not only for exploring neural plasticity in the adult human brain but also for understanding the relationship between the activity of sensory neurons and conscious experience. We conclude with a theory of phantom limbs, some striking demonstrations of phantoms induced in normal subjects, and some remarks about the relevance of these phenomena to the question of how the brain constructs a 'body image.' PMID:9762952

  18. Adult Human Neurogenesis: From Microscopy to Magnetic Resonance Imaging

    PubMed Central

    Sierra, Amanda; Encinas, Juan M.; Maletic-Savatic, Mirjana

    2011-01-01

    Neural stem cells reside in well-defined areas of the adult human brain and are capable of generating new neurons throughout the life span. In rodents, it is well established that the new born neurons are involved in olfaction as well as in certain forms of memory and learning. In humans, the functional relevance of adult human neurogenesis is being investigated, in particular its implication in the etiopathology of a variety of brain disorders. Adult neurogenesis in the human brain was discovered by utilizing methodologies directly imported from the rodent research, such as immunohistological detection of proliferation and cell-type specific biomarkers in postmortem or biopsy tissue. However, in the vast majority of cases, these methods do not support longitudinal studies; thus, the capacity of the putative stem cells to form new neurons under different disease conditions cannot be tested. More recently, new technologies have been specifically developed for the detection and quantification of neural stem cells in the living human brain. These technologies rely on the use of magnetic resonance imaging, available in hospitals worldwide. Although they require further validation in rodents and primates, these new methods hold the potential to test the contribution of adult human neurogenesis to brain function in both health and disease. This review reports on the current knowledge on adult human neurogenesis. We first review the different methods available to assess human neurogenesis, both ex vivo and in vivo and then appraise the changes of adult neurogenesis in human diseases. PMID:21519376

  19. Phytoestrogen Metabolism by Adult Human Gut Microbiota.

    PubMed

    Gaya, Pilar; Medina, Margarita; Sánchez-Jiménez, Abel; Landete, José Mᵃ

    2016-01-01

    Phytoestrogens are plant-derived polyphenols with a structure similar to human estrogens. The three main groups of phytoestrogens, isoflavones, ellagitannins, and lignans, are transformed into equol, urolithins, and enterolignans, respectively, by bacteria. These metabolites have more estrogenic/antiestrogenic and antioxidant activities than their precursors, and they are more bioavailable. The aim of this study was to analyze the metabolism of isoflavones, lignans and ellagitannins by gut microbiota, and to study the possible correlation in the metabolism of these three groups of phytoestrogens. In vitro fermentation experiments were performed with feces samples from 14 healthy adult volunteers, and metabolite formation was measured by HPLC-PAD and HPLC-ESI/MS. Only the microbiota of one subject produced equol, while most of them showed production of O-desmethylangolensin (O-DMA). Significant inter-subject differences were observed in the metabolism of dihydrodaidzein and dihydrogenistein, while the glucoside isoflavones and their aglycones showed less variability, except for glycitin. Most subjects produced urolithins M-5 and E. Urolithin D was not detected, while uroltithin B was found in half of the individuals analyzed, and urolithins A and C were detected in two and four subjects, respectively. Enterolactone was found in all subjects, while enterodiol only appeared in five. Isoflavone metabolism could be correlated with the metabolism of lignans and ellagitannins. However, the metabolism of ellagitannins and lignans could not be correlated. This the first study where the metabolism of the three groups together of phytoestrogen, isoflavones, lignans, and ellagitannins by gut microbiota is analyzed. PMID:27517891

  20. Gustofacial and olfactofacial responses in human adults.

    PubMed

    Weiland, Romy; Ellgring, Heiner; Macht, Michael

    2010-11-01

    Adults' facial reactions in response to tastes and odors were investigated in order to determine whether differential facial displays observed in newborns remain stable in adults who exhibit a greater voluntary facial control. Twenty-eight healthy nonsmokers (14 females) tasted solutions of PROP (bitter), NaCl (salty), citric acid (sour), sucrose (sweet), and glutamate (umami) differing in concentration (low, medium, and high) and smelled different odors (banana, cinnamon, clove, coffee, fish, and garlic). Their facial reactions were video recorded and analyzed using the Facial Action Coding System. Adults' facial reactions discriminated between stimuli with opponent valences. Unpleasant tastes and odors elicited negative displays (brow lower, upper lip raise, and lip corner depress). The pleasant sweet taste elicited positive displays (lip suck), whereas the pleasant odors did not. Unlike newborns, adults smiled with higher concentrations of some unpleasant tastes that can be regarded as serving communicative functions. Moreover, adults expressed negative displays with higher sweetness. Except for the "social" smile in response to unpleasant tastes, adults' facial reactions elicited by tastes and odors mostly correspond to those found in newborns. In conclusion, adults' facial reactions to tastes and odors appear to remain stable in their basic displays; however, some additional reactions might reflect socialization influences.

  1. NUNDO: a numerical model of a human torso phantom and its application to effective dose equivalent calculations for astronauts at the ISS.

    PubMed

    Puchalska, Monika; Bilski, Pawel; Berger, Thomas; Hajek, Michael; Horwacik, Tomasz; Körner, Christine; Olko, Pawel; Shurshakov, Vyacheslav; Reitz, Günther

    2014-11-01

    The health effects of cosmic radiation on astronauts need to be precisely quantified and controlled. This task is important not only in perspective of the increasing human presence at the International Space Station (ISS), but also for the preparation of safe human missions beyond low earth orbit. From a radiation protection point of view, the baseline quantity for radiation risk assessment in space is the effective dose equivalent. The present work reports the first successful attempt of the experimental determination of the effective dose equivalent in space, both for extra-vehicular activity (EVA) and intra-vehicular activity (IVA). This was achieved using the anthropomorphic torso phantom RANDO(®) equipped with more than 6,000 passive thermoluminescent detectors and plastic nuclear track detectors, which have been exposed to cosmic radiation inside the European Space Agency MATROSHKA facility both outside and inside the ISS. In order to calculate the effective dose equivalent, a numerical model of the RANDO(®) phantom, based on computer tomography scans of the actual phantom, was developed. It was found that the effective dose equivalent rate during an EVA approaches 700 μSv/d, while during an IVA about 20 % lower values were observed. It is shown that the individual dose based on a personal dosimeter reading for an astronaut during IVA results in an overestimate of the effective dose equivalent of about 15 %, whereas under an EVA conditions the overestimate is more than 200 %. A personal dosemeter can therefore deliver quite good exposure records during IVA, but may overestimate the effective dose equivalent received during an EVA considerably. PMID:25119442

  2. NUNDO: a numerical model of a human torso phantom and its application to effective dose equivalent calculations for astronauts at the ISS.

    PubMed

    Puchalska, Monika; Bilski, Pawel; Berger, Thomas; Hajek, Michael; Horwacik, Tomasz; Körner, Christine; Olko, Pawel; Shurshakov, Vyacheslav; Reitz, Günther

    2014-11-01

    The health effects of cosmic radiation on astronauts need to be precisely quantified and controlled. This task is important not only in perspective of the increasing human presence at the International Space Station (ISS), but also for the preparation of safe human missions beyond low earth orbit. From a radiation protection point of view, the baseline quantity for radiation risk assessment in space is the effective dose equivalent. The present work reports the first successful attempt of the experimental determination of the effective dose equivalent in space, both for extra-vehicular activity (EVA) and intra-vehicular activity (IVA). This was achieved using the anthropomorphic torso phantom RANDO(®) equipped with more than 6,000 passive thermoluminescent detectors and plastic nuclear track detectors, which have been exposed to cosmic radiation inside the European Space Agency MATROSHKA facility both outside and inside the ISS. In order to calculate the effective dose equivalent, a numerical model of the RANDO(®) phantom, based on computer tomography scans of the actual phantom, was developed. It was found that the effective dose equivalent rate during an EVA approaches 700 μSv/d, while during an IVA about 20 % lower values were observed. It is shown that the individual dose based on a personal dosimeter reading for an astronaut during IVA results in an overestimate of the effective dose equivalent of about 15 %, whereas under an EVA conditions the overestimate is more than 200 %. A personal dosemeter can therefore deliver quite good exposure records during IVA, but may overestimate the effective dose equivalent received during an EVA considerably.

  3. Adult Literacy Education and Human Rights: A View from Afghanistan

    ERIC Educational Resources Information Center

    Andersen, Susan M.; Kooij, Christina S.

    2007-01-01

    In this article, we argue that adult literacy as part of international development is an issue of both human rights and women's rights. We explore this by presenting a case study of the effects of one innovative adult literacy program in Afghanistan that places men and women, as well as various ethnicities, together in the same classroom as…

  4. Mathematical phantoms for evaluation of age-specific internal dose

    SciTech Connect

    Cristy, M.

    1980-01-01

    A series of mathematical phantoms representing children has been developed for use with photon transport codes. These phantoms, patterned after the Fisher-Snyder adult phantom, consist of simple mathematical expressions for the boundaries of the major organs and body sections. The location and shape of the organs are consistent with drawings depicting developmental anatomy, with the organ volumes assigned such that the masses at the various ages conform closely with the data presented in Reference Man. The explicit mathematical expressions for the various ages overcome the potential misrepresentation of organ sizes that occurred in phantoms derived from simple mathematical transformations of the adult phantom. Female breast tissue has been added to the phantoms, including the adult, now allowing assessment of doses to this organ.

  5. A comparative study of bifidobacteria in human babies and adults

    PubMed Central

    KHONSARI, Shadi; SUGANTHY, Mayuran; BURCZYNSKA, Beata; DANG, Vu; CHOUDHURY, Manika; PACHENARI, Azra

    2015-01-01

    The composition and diversity of the gut microbiota are known to be different between babies and adults. The aim of this project was to compare the level of bifidobacteria between babies and adults and to investigate the influence of lifestyle factors on the level of this bacterium in the gut. During this study, the levels of bifidobacteria in 10 human babies below 2 years of age were compared with that of 10 human adults above 40 years. The level of bifidobacteria proved to be significantly higher in babies in comparison with adults. This investigation concluded that a combination of several factors, such as age, diet, and BMI, has an important effect on the level of bifidobacteria in adults, while in babies, a combination of diet and age may influence the level of intestinal bifidobacteria. PMID:27200263

  6. Progress in theoretical, experimental, and computational investigations in turbid tissue phantoms and human teeth using laser infrared photothermal radiometry

    NASA Astrophysics Data System (ADS)

    Mandelis, Andreas

    2002-03-01

    This paper reviews and describes the state-of-the-art in the development of frequency-domain infrared photothermal radiometry (FD-PTR) for biomedical and dental applications. The emphasis is placed on the measurement of the optical and thermal properties of tissue-like materials using FD-PTR. A rigorous three-dimensional thermal-wave formulation with three-dimensional diffuse and coherent photon-density-wave sources is presented, and is applied to data from model tissue phantoms and dental enamel samples. The combined theoretical, experimental and computational methodology shows good promise with regard to its analytical ability to measure optical properties of turbid media uniquely, as compared to PPTR, which exhibits uniqueness problems. From data sets obtained with calibrated test phantoms, the reduced optical scattering and absorption coefficients were found to be within 20% and 10%, respectively, from the independently derived values using Mie scattering theory and spectrophotometric measurements. Furthermore, the state-of-the-art and recent developments in applications of laser infrared FD-PTR to dental caries research is described, with examples and histological studies from carious dental tissue. The correlation of PTR signals with modulated dental luminescence is discussed as a very promising potential quantitative methodology for the clinical diagnosis of sub-surface incipient dental caries. The application of the turbid-medium thermal-wave model to the measurement of the optical absorption and scattering coefficients of enamel is also presented.

  7. Simultaneous assessment of arsenic and selenium in human nail phantoms using a portable x-ray tube and a detector.

    PubMed

    Roy, Christopher W; Gherase, Mihai Raul; Fleming, David E B

    2010-03-21

    A novel approach to the measurement of arsenic and selenium in nail phantoms is demonstrated. Two-component nail phantoms of 0.7 mm and 1.5 mm thickness were made from a polyester resin-salt mixture and dosed with equal arsenic and selenium concentrations ranging from 0 to 30 microg g(-1). A backing was made to simulate the soft tissue and bone of the great toe. Characteristic x-rays for arsenic and selenium were recorded using a portable x-ray tube and a silicon PiN diode detector. The minimum instrumental detection limits for arsenic and selenium in 0.7 mm solitary nail samples were as follows: 0.510 +/- 0.018 microg g(-1) and 0.519 +/- 0.026 microg g(-1) respectively; for 1.5 mm solitary nail: 0.465 +/- 0.035 microg g(-1) and 0.561 +/- 0.062 microg g(-1); for 0.7 mm nail with backing: 1.522 +/- 0.038 microg g(-1) and 1.401 +/- 0.049 microg g(-1); for 1.5 mm nail with backing: 1.354 +/- 0.054 microg g(-1) and 1.367 +/- 0.068 microg g(-1). PMID:20182007

  8. 21 CFR 892.1370 - Nuclear anthropomorphic phantom.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1370 Nuclear anthropomorphic phantom. (a) Identification. A nuclear anthropomorphic phantom is a human tissue facsimile that contains a... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Nuclear anthropomorphic phantom. 892.1370...

  9. 21 CFR 892.1370 - Nuclear anthropomorphic phantom.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1370 Nuclear anthropomorphic phantom. (a) Identification. A nuclear anthropomorphic phantom is a human tissue facsimile that contains a... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nuclear anthropomorphic phantom. 892.1370...

  10. 21 CFR 892.1370 - Nuclear anthropomorphic phantom.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Nuclear anthropomorphic phantom. 892.1370 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1370 Nuclear anthropomorphic phantom. (a) Identification. A nuclear anthropomorphic phantom is a human tissue facsimile that contains...

  11. 21 CFR 892.1370 - Nuclear anthropomorphic phantom.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Nuclear anthropomorphic phantom. 892.1370 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1370 Nuclear anthropomorphic phantom. (a) Identification. A nuclear anthropomorphic phantom is a human tissue facsimile that contains...

  12. 21 CFR 892.1370 - Nuclear anthropomorphic phantom.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Nuclear anthropomorphic phantom. 892.1370 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1370 Nuclear anthropomorphic phantom. (a) Identification. A nuclear anthropomorphic phantom is a human tissue facsimile that contains...

  13. Construction of boundary-surface-based Chinese female astronaut computational phantom and proton dose estimation.

    PubMed

    Sun, Wenjuan; Jia, Xianghong; Xie, Tianwu; Xu, Feng; Liu, Qian

    2013-03-01

    With the rapid development of China's space industry, the importance of radiation protection is increasingly prominent. To provide relevant dose data, we first developed the Visible Chinese Human adult Female (VCH-F) phantom, and performed further modifications to generate the VCH-F Astronaut (VCH-FA) phantom, incorporating statistical body characteristics data from the first batch of Chinese female astronauts as well as reference organ mass data from the International Commission on Radiological Protection (ICRP; both within 1% relative error). Based on cryosection images, the original phantom was constructed via Non-Uniform Rational B-Spline (NURBS) boundary surfaces to strengthen the deformability for fitting the body parameters of Chinese female astronauts. The VCH-FA phantom was voxelized at a resolution of 2 × 2 × 4 mm(3)for radioactive particle transport simulations from isotropic protons with energies of 5000-10 000 MeV in Monte Carlo N-Particle eXtended (MCNPX) code. To investigate discrepancies caused by anatomical variations and other factors, the obtained doses were compared with corresponding values from other phantoms and sex-averaged doses. Dose differences were observed among phantom calculation results, especially for effective dose with low-energy protons. Local skin thickness shifts the breast dose curve toward high energy, but has little impact on inner organs. Under a shielding layer, organ dose reduction is greater for skin than for other organs. The calculated skin dose per day closely approximates measurement data obtained in low-Earth orbit (LEO).

  14. Development of a practical ultrasonic approach for simultaneous measurement of the thickness and the sound speed in human skull bones: a laboratory phantom study

    NASA Astrophysics Data System (ADS)

    Wydra, A.; Malyarenko, E.; Shapoori, K.; Maev, R. Gr

    2013-02-01

    The availability of a non-invasive express method for the in vivo measurement of both sound velocity and thickness of the human skull bone would be of great benefit to various transcranial ultrasonic imaging and treatment applications. This paper investigates two ultrasonic methods that measure both parameters and are based on the variable focus technique. All the experiments described in this paper were conducted on specially prepared custom skull bone phantoms, including flat and deformed samples, designed and developed in our laboratory. The first method uses a single immersion 2.25 MHz ultrasonic transducer consecutively focused on the front and back surfaces of the sample. The accuracy and precision of this method are demonstrated via single point measurements on flat samples with and without porosity. The measurement results from a specimen with the randomly curved back surface show the possibility of obtaining the inner profile of the skull bone. The second presented method is a practical modification of the variable focus technique for the linear phased array case. The method was tested on flat and curved skull bone phantoms with and without inner porosity showing higher measurement accuracy and simpler practical realization than its scanning counterpart.

  15. Influence of dentures on SAR in the visible Chinese human head voxel phantom exposed to a mobile phone at 900 and 1800 MHz.

    PubMed

    Yu, Dong; Zhang, Ruoyu; Liu, Qian

    2012-09-01

    To investigate the influence of dentures on electromagnetic energy absorption during the daily use of a mobile phone, a high-resolution head phantom based on the Visible Chinese Human dataset was reconstructed. Simulations on phantoms with various dentures were performed by using the finite-difference time-domain method with a 0.47 wavelength dipole antenna and a mobile phone model as radiation sources at 900 and 1800 MHz. The Specific energy Absorption Rate (SAR) values including 1 and 10 g average SAR values were assessed. When the metallic dental crowns with resonance lengths of approximately one-third to one-half wavelength in the tissue nearby are parallel to the radiation source, up to 121.6% relative enhancement for 1 g average SAR and 17.1% relative enhancement for 10 g average SAR are observed due to the resonance effect in energy absorption. When the radiation sources operate in the normal configuration, the 10 g average SAR values are still in compliance with the basic restrictions established by the Institute of Electrical and Electronic Engineers (IEEE) and the International Commission on Non-Ionizing Radiation Protection (ICNIRP), indicating that the safety limits will not be challenged by the usage of dentures.

  16. Image based Monte Carlo Modeling for Computational Phantom

    NASA Astrophysics Data System (ADS)

    Cheng, Mengyun; Wang, Wen; Zhao, Kai; Fan, Yanchang; Long, Pengcheng; Wu, Yican

    2014-06-01

    The evaluation on the effects of ionizing radiation and the risk of radiation exposure on human body has been becoming one of the most important issues for radiation protection and radiotherapy fields, which is helpful to avoid unnecessary radiation and decrease harm to human body. In order to accurately evaluate the dose on human body, it is necessary to construct more realistic computational phantom. However, manual description and verfication of the models for Monte carlo(MC)simulation are very tedious, error-prone and time-consuming. In addiation, it is difficult to locate and fix the geometry error, and difficult to describe material information and assign it to cells. MCAM (CAD/Image-based Automatic Modeling Program for Neutronics and Radiation Transport Simulation) was developed as an interface program to achieve both CAD- and image-based automatic modeling by FDS Team (Advanced Nuclear Energy Research Team, http://www.fds.org.cn). The advanced version (Version 6) of MCAM can achieve automatic conversion from CT/segmented sectioned images to computational phantoms such as MCNP models. Imaged-based automatic modeling program(MCAM6.0) has been tested by several medical images and sectioned images. And it has been applied in the construction of Rad-HUMAN. Following manual segmentation and 3D reconstruction, a whole-body computational phantom of Chinese adult female called Rad-HUMAN was created by using MCAM6.0 from sectioned images of a Chinese visible human dataset. Rad-HUMAN contains 46 organs/tissues, which faithfully represented the average anatomical characteristics of the Chinese female. The dose conversion coefficients(Dt/Ka) from kerma free-in-air to absorbed dose of Rad-HUMAN were calculated. Rad-HUMAN can be applied to predict and evaluate dose distributions in the Treatment Plan System (TPS), as well as radiation exposure for human body in radiation protection.

  17. Neural stem cells in the adult human brain

    PubMed Central

    Gonzalez-Perez, Oscar

    2012-01-01

    For decades, it was believed that the adult brain was a quiescent organ unable to produce new neurons. At the beginning of the1960's, this dogma was challenged by a small group of neuroscientists. To date, it is well-known that new neurons are generated in the adult brain throughout life. Adult neurogenesis is primary confined to the subventricular zone (SVZ) of the forebrain and the subgranular zone of the dentate gyrus within the hippocampus. In both the human and the rodent brain, the primary progenitor of adult SVZ is a subpopulation of astrocytes that have stem-cell-like features. The human SVZ possesses a peculiar cell composition and displays important organizational differences when compared to the SVZ of other mammals. Some evidence suggests that the human SVZ may be not only an endogenous source of neural precursor cells for brain repair, but also a source of brain tumors. In this review, we described the cytoarchitecture and cellular composition of the SVZ in the adult human brain. We also discussed some clinical implications of SVZ, such as: stem-cell-based therapies against neurodegenerative diseases and its potential as a source of malignant cells. Understanding the biology of human SVZ and its neural progenitors is one of the crucial steps to develop novel therapies against neurological diseases in humans. PMID:23181200

  18. Instrumentation for investigation of the depth-dose distribution by the Liulin-5 instrument of a human phantom on the Russian segment of ISS for estimation of the radiation risk during long term space flights

    NASA Technical Reports Server (NTRS)

    Semkova, J.; Koleva, R.; Todorova, G.; Kanchev, N.; Petrov, V.; Shurshakov, V.; Tchhernykh, I.; Kireeva, S.

    2004-01-01

    Described is the Liulin-5 experiment and instrumentation, developed for investigation of the space radiation doses depth distribution in a human phantom on the Russian Segment of the International Space Station (ISS). Liulin-5 experiment is a part of the international project MATROSHKA-R on ISS. The experiment MATROSHKA-R is aimed to study the depth dose distribution at the sites of critical organs of the human body, using models of human body-anthropomorphic and spherical tissue-equivalent phantoms. The aim of Liulin-5 experiment is long term (4-5 years) investigation of the radiation environment dynamics inside the spherical tissue-equivalent phantom, mounted in different places of the Russian Segment of ISS. Energy deposition spectra, linear energy transfer spectra, flux and dose rates for protons and the biologically-relevant heavy ion components of the galactic cosmic radiation will be measured simultaneously with near real time resolution at different depths of the phantom by a telescope of silicon detectors. Data obtained together with data from other active and passive dosimeters will be used to estimate the radiation risk to the crewmembers, verify the models of radiation environment in low Earth orbit, validate body transport model and correlate organ level dose to skin dose. Presented are the test results of the prototype unit. The spherical phantom will be flown on the ISS in 2004 year and Liulin-5 experiment is planned for 2005 year. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

  19. Humanities and the Adult Learner in an Information Society.

    ERIC Educational Resources Information Center

    Myers, Dale; Kamholtz, Jonathan

    Humanities courses have often been given little attention in continuing education for adults, possibly because they have been viewed as not "practical" or not "job-oriented" enough in our career-oriented, technologically advanced society. However, the humanities should be an integral part of our culture and of the lives of educated persons--a…

  20. Simulation Of Human Body Radiation Using Phantom Model On Beam_nrc And Verification On Dosxyz_nrc

    NASA Astrophysics Data System (ADS)

    Adiba, Amalia Istiqlali; Haryanto, Freddy

    2010-12-01

    The optimum dose can be produced by measuring and analysis of the dose distribution from the source. The energy of the source must be maximum for the target cell, and must minimum for the tissues that surround the target cell. In this study, the phantom model has a cylindrical shape with 20 cm radius and 19 cm depth. The calculation is done where photon beam energy is 6 MeV with 3 different radius beam; 0.3 cm, 5 cm, and 15 cm. The verification was done with a model cube film which was arranged by element voxel which made by Mylar and Ag. The results of this simulation shows the difference dose distribution for radius beam 0.5 cm, 3 cm, and 15 cm that is caused by particle density and penumbra effect. And for all beam radiuses, the maximum dose (100%) happens in 1.5-2 mm depth from film model.

  1. Eigenbreasts for statistical breast phantoms

    NASA Astrophysics Data System (ADS)

    Sturgeon, Gregory M.; Tward, Daniel J.; Ketcha, M.; Ratnanather, J. T.; Miller, M. I.; Park, Subok; Segars, W. P.; Lo, Joseph Y.

    2016-03-01

    To facilitate rigorous virtual clinical trials using model observers for breast imaging optimization and evaluation, we demonstrated a method of defining statistical models, based on 177 sets of breast CT patient data, in order to generate tens of thousands of unique digital breast phantoms. In order to separate anatomical texture from variation in breast shape, each training set of breast phantoms were deformed to a consistent atlas compressed geometry. Principal component analysis (PCA) was then performed on the shape-matched breast CT volumes to capture the variation of patient breast textures. PCA decomposes the training set of N breast CT volumes into an N-1-dimensional space of eigenvectors, which we call eigenbreasts. By summing weighted combinations of eigenbreasts, a large ensemble of different breast phantoms can be newly created. Different training sets can be used in eigenbreast analysis for designing basis models to target sub-populations defined by breast characteristics, such as size or density. In this work, we plan to generate ensembles of 30,000 new phantoms based on glandularity for an upcoming virtual trial of lesion detectability in digital breast tomosynthesis. Our method extends our series of digital and physical breast phantoms based on human subject anatomy, providing the capability to generate new, unique ensembles consisting of tens of thousands or more virtual subjects. This work represents an important step towards conducting future virtual trials for tasks-based assessment of breast imaging, where it is vital to have a large ensemble of realistic phantoms for statistical power as well as clinical relevance.

  2. Anatomically correct deformable colon phantom

    NASA Astrophysics Data System (ADS)

    Norris, James A.; Barton, Michael D.; Davis, Brynmor J.; Bieszczad, Jerry; Meunier, Norm L.; Brown, Nathan W.; Kynor, David B.

    2011-03-01

    We describe a technique to build a soft-walled colon phantom that provides realistic lumen anatomy in computed tomography (CT) images. The technique begins with the geometry of a human colon measured during CT colonography (CTC). The three-dimensional air-filled colonic lumen is segmented and then replicated using stereolithography (SLA). The rigid SLA model includes large-scale features (e.g., haustral folds and tenia coli bands) down to small-scale features (e.g., a small pedunculated polyp). Since the rigid model represents the internal air-filled volume, a highly-pliable silicone polymer is painted onto the rigid model. This thin layer of silicone, when removed, becomes the colon wall. Small 3 mm diameter glass beads are affixed to the outer wall. These glass beads show up with high intensity in CT scans and provide a ground truth for evaluating performance of algorithms designed to register prone and supine CTC data sets. After curing, the silicone colon wall is peeled off the rigid model. The resulting colon phantom is filled with air and submerged in a water bath. CT images and intraluminal fly-through reconstructions from CTC scans of the colon phantom are compared against patient data to demonstrate the ability of the phantom to simulate a human colon.

  3. Teaching Human Rights: Grades 7 through Adult.

    ERIC Educational Resources Information Center

    Shiman, David A.

    This curriculum resource on human rights is rooted in the United Nations Universal Declaration of Human Rights and seeks to help students understand the issues involved. Using the rights categories suggested by the Universal Declaration, this book offers new ways of teaching about familiar themes. The book contains activities to encourage students…

  4. Design of a digital phantom population for myocardial perfusion SPECT imaging research

    NASA Astrophysics Data System (ADS)

    Ghaly, Michael; Du, Yong; Fung, George S. K.; Tsui, Benjamin M. W.; Links, Jonathan M.; Frey, Eric

    2014-06-01

    Digital phantoms and Monte Carlo (MC) simulations have become important tools for optimizing and evaluating instrumentation, acquisition and processing methods for myocardial perfusion SPECT (MPS). In this work, we designed a new adult digital phantom population and generated corresponding Tc-99m and Tl-201 projections for use in MPS research. The population is based on the three-dimensional XCAT phantom with organ parameters sampled from the Emory PET Torso Model Database. Phantoms included three variations each in body size, heart size, and subcutaneous adipose tissue level, for a total of 27 phantoms of each gender. The SimSET MC code and angular response functions were used to model interactions in the body and the collimator-detector system, respectively. We divided each phantom into seven organs, each simulated separately, allowing use of post-simulation summing to efficiently model uptake variations. Also, we adapted and used a criterion based on the relative Poisson effective count level to determine the required number of simulated photons for each simulated organ. This technique provided a quantitative estimate of the true noise in the simulated projection data, including residual MC simulation noise. Projections were generated in 1 keV wide energy windows from 48-184 keV assuming perfect energy resolution to permit study of the effects of window width, energy resolution, and crosstalk in the context of dual isotope MPS. We have developed a comprehensive method for efficiently simulating realistic projections for a realistic population of phantoms in the context of MPS imaging. The new phantom population and realistic database of simulated projections will be useful in performing mathematical and human observer studies to evaluate various acquisition and processing methods such as optimizing the energy window width, investigating the effect of energy resolution on image quality and evaluating compensation methods for degrading factors such as crosstalk in

  5. Design of a digital phantom population for myocardial perfusion SPECT imaging research

    PubMed Central

    Ghaly, Michael; Du, Yong; Fung, George S.K.; Tsui, Benjamin M.W.; Links, Jonathan M.; Frey, Eric

    2014-01-01

    Digital phantoms and Monte Carlo (MC) simulations have become important tools for optimizing and evaluating instrumentation, acquisition and processing methods for myocardial perfusion SPECT (MPS). In this work, we designed a new adult digital phantom population and generated corresponding Tc-99m and Tl-201 projections for use in MPS research. The population is based on the 3D XCAT phantom with organ parameters sampled from the Emory PET Torso Model Database. Phantoms included 3 variations each in body size, heart size, and subcutaneous adipose tissue level, for a total of 27 phantoms of each gender. The SimSET Monte Carlo code and angular response functions were used to model interactions in the body and the collimator-detector system, respectively. We divided each phantom into seven organs, each simulated separately, allowing use of post-simulation summing to efficiently model uptake variations. Also, we adapted and used a criterion based on the relative Poisson effective count level to determine the required number of simulated photons for each simulated organ. This technique provided a quantitative estimate of the true noise in the simulated projection data, including residual MC simulation noise. Projections were generated in 1 keV wide energy windows from 48-184 keV assuming perfect energy resolution to permit study of the effects of window width, energy resolution, and crosstalk in the context of dual isotope MPS. We have developed a comprehensive method for efficiently simulating realistic projections for a realistic population of phantoms in the context of MPS imaging. The new phantom population and realistic database of simulated projections will be useful in performing mathematical and human observer studies to evaluate various acquisition and processing methods such as optimizing the energy window width, investigating the effect of energy resolution on image quality and evaluating compensation methods for degrading factors such as crosstalk in the

  6. Influence of a fat layer on the near infrared spectra of human muscle: quantitative analysis based on two-layered Monte Carlo simulations and phantom experiments

    NASA Technical Reports Server (NTRS)

    Yang, Ye; Soyemi, Olusola O.; Landry, Michelle R.; Soller, Babs R.

    2005-01-01

    The influence of fat thickness on the diffuse reflectance spectra of muscle in the near infrared (NIR) region is studied by Monte Carlo simulations of a two-layer structure and with phantom experiments. A polynomial relationship was established between the fat thickness and the detected diffuse reflectance. The influence of a range of optical coefficients (absorption and reduced scattering) for fat and muscle over the known range of human physiological values was also investigated. Subject-to-subject variation in the fat optical coefficients and thickness can be ignored if the fat thickness is less than 5 mm. A method was proposed to correct the fat thickness influence. c2005 Optical Society of America.

  7. New neurons in the adult striatum: from rodents to humans

    PubMed Central

    Inta, Dragos; Cameron, Heather A.; Gass, Peter

    2015-01-01

    Most neurons are generated during development and are not replaced during adulthood, even if they are lost to injury or disease. It is firmly established, however, that new neurons are generated in the dentate gyrus of the hippocampus of virtually all adult mammals, including humans [1]. Many questions still remain, however, regarding adult neurogenesis in other brain regions and particularly in humans, where standard birthdating methods are not generally feasible. Exciting recent evidence indicates that calretinin-expressing interneurons are added to the adult human striatum at a substantial rate [2]. The role of new neurons is unknown, but studies in rodents will be able to further elucidate their identity and origin and then begin to understand their regulation and function. PMID:26298770

  8. Adult human metapneumonovirus (hMPV) pneumonia mimicking Legionnaire's disease.

    PubMed

    Cunha, Burke A; Irshad, Nadia; Connolly, James J

    2016-01-01

    In adults hospitalized with viral pneumonias the main differential diagnostic consideration is influenza pneumonia. The respiratory viruses causing viral influenza like illnesses (ILIs), e.g., RSV may closely resemble influenza. Rarely, extrapulmonary findings of some ILIs may resemble Legionnaire's disease (LD), e.g., adenovirus, human parainfluenza virus (HPIV-3). We present a most unusual case of human metapneumonovirus pneumonia (hMPV) with some characteristic extrapulmonary findings characteristic of LD, e.g., relative bradycardia, as well as mildly elevated serum transaminases and hyphosphatemia. We believe this is the first reported case of hMPV pneumonia in a hospitalized adult that had some features of LD.

  9. Adult human metapneumonovirus (hMPV) pneumonia mimicking Legionnaire's disease.

    PubMed

    Cunha, Burke A; Irshad, Nadia; Connolly, James J

    2016-01-01

    In adults hospitalized with viral pneumonias the main differential diagnostic consideration is influenza pneumonia. The respiratory viruses causing viral influenza like illnesses (ILIs), e.g., RSV may closely resemble influenza. Rarely, extrapulmonary findings of some ILIs may resemble Legionnaire's disease (LD), e.g., adenovirus, human parainfluenza virus (HPIV-3). We present a most unusual case of human metapneumonovirus pneumonia (hMPV) with some characteristic extrapulmonary findings characteristic of LD, e.g., relative bradycardia, as well as mildly elevated serum transaminases and hyphosphatemia. We believe this is the first reported case of hMPV pneumonia in a hospitalized adult that had some features of LD. PMID:26988110

  10. Development of a percutaneous optical imaging system for tracking vascular gene expression: a feasibility study using human tissuelike phantoms

    NASA Astrophysics Data System (ADS)

    Kar, Sourav K.; Kumar, Ananda; Yang, Xiaoming

    2004-05-01

    Noninvasive tracking of vascular gene delivery and expression forms an important part of successfully implementing vascular gene therapy methods for the treatment of atherosclerosis and various cardiovascular disorders. While ultrasound and MR imaging have shown promise in the monitoring of gene delivery to the vasculatures, optical imaging has shown promise for tracking gene expression. Optical imaging using bioreporter genes like Green Fluorescent Protein (GFP), Red Fluorescent Protein (RFP) and Luciferase to track and localize the therapeutic gene have helped provide an in vivo detection method of the process. The usage of GFP and RFP entails the detection of the fluorescent signal emitted by them on excitation with light of appropriate wavelength. We have developed a novel percutaneous optical imaging system that may be used for in vivo tracking vascular fluorescent gene expression in deep-seated vessels. It is based on the detection of the fluorescent signal emitted from GFP tagged cells. This phantom study was carried out to investigate the performance of the optical imaging system and gain insights into its performance record and study improvisation possibilities.

  11. The reference phantoms: voxel vs polygon.

    PubMed

    Kim, C H; Yeom, Y S; Nguyen, T T; Wang, Z J; Kim, H S; Han, M C; Lee, J K; Zankl, M; Petoussi-Henss, N; Bolch, W E; Lee, C; Chung, B S

    2016-06-01

    The International Commission on Radiological Protection (ICRP) reference male and female adult phantoms, described in Publication 110, are voxel phantoms based on whole-body computed tomography scans of a male and a female patient, respectively. The voxel in-plane resolution and the slice thickness, of the order of a few millimetres, are insufficient for proper segmentation of smaller tissues such as the lens of the eye, the skin, and the walls of some organs. The calculated doses for these tissues therefore present some limitations, particularly for weakly penetrating radiation. Similarly, the Publication 110 phantoms cannot represent 8-40-µm-thick target regions in respiratory or alimentary tract organs. Separate stylised models have been used to represent these tissues for calculation of the ICRP reference dose coefficients (DCs). ICRP Committee 2 recently initiated a research project, the ultimate goal of which is to convert the Publication 110 phantoms to a high-quality polygon-mesh (PM) format, including all source and target regions, even those of the 8-40-µm-thick alimentary and respiratory tract organs. It is expected that the converted phantoms would lead to the same or very similar DCs as the Publication 110 reference phantoms for penetrating radiation and, at the same time, provide more accurate DCs for weakly penetrating radiation and small tissues. Additionally, the reference phantoms in the PM format would be easily deformable and, as such, could serve as a starting point to create phantoms of various postures for use, for example, in accidental dose calculations. This paper will discuss the current progress of the phantom conversion project and its significance for ICRP DC calculations.

  12. Late Pleistocene adult mortality patterns and modern human establishment

    PubMed Central

    Trinkaus, Erik

    2011-01-01

    The establishment of modern humans in the Late Pleistocene, subsequent to their emergence in eastern Africa, is likely to have involved substantial population increases, during their initial dispersal across southern Asia and their subsequent expansions throughout Africa and into more northern Eurasia. An assessment of younger (20–40 y) versus older (>40 y) adult mortality distributions for late archaic humans (principally Neandertals) and two samples of early modern humans (Middle Paleolithic and earlier Upper Paleolithic) provides little difference across the samples. All three Late Pleistocene samples have a dearth of older individuals compared with Holocene ethnographic/historical samples. They also lack older adults compared with Holocene paleodemographic profiles that have been critiqued for having too few older individuals for subsistence, social, and demographic viability. Although biased, probably through a combination of preservation, age assessment, and especially Pleistocene mobility requirements, these adult mortality distributions suggest low life expectancy and demographic instability across these Late Pleistocene human groups. They indicate only subtle and paleontologically invisible changes in human paleodemographics with the establishment of modern humans; they provide no support for a life history advantage among early modern humans. PMID:21220336

  13. Novel surface markers directed against adult human gallbladder.

    PubMed

    Galivo, Feorillo H; Dorrell, Craig; Grompe, Maria T; Zhong, YongPing; Streeter, Philip R; Grompe, Markus

    2015-07-01

    Novel cell surface-reactive monoclonal antibodies generated against extrahepatic biliary cells were developed for the isolation and characterization of different cell subsets from normal adult human gallbladder. Eleven antigenically distinct gallbladder subpopulations were isolated by fluorescence-activated cell sorting. They were classified into epithelial, mesenchymal, and pancreatobiliary (PDX1(+)SOX9(+)) subsets based on gene expression profiling. These antigenically distinct human gallbladder cell subsets could potentially also reflect different functional properties in regards to bile physiology, cell renewal and plasticity. Three of the novel monoclonal antibodies differentially labeled archival sections of primary carcinoma of human gallbladder relative to normal tissue. The novel monoclonal antibodies described herein enable the identification and characterization of antigenically diverse cell subsets within adult human gallbladder and are putative tumor biomarkers.

  14. Age-Related Gene Expression Differences in Monocytes from Human Neonates, Young Adults, and Older Adults

    PubMed Central

    Tong, Ann-Jay; Kollmann, Tobias R.; Smale, Stephen T.

    2015-01-01

    A variety of age-related differences in the innate and adaptive immune systems have been proposed to contribute to the increased susceptibility to infection of human neonates and older adults. The emergence of RNA sequencing (RNA-seq) provides an opportunity to obtain an unbiased, comprehensive, and quantitative view of gene expression differences in defined cell types from different age groups. An examination of ex vivo human monocyte responses to lipopolysaccharide stimulation or Listeria monocytogenes infection by RNA-seq revealed extensive similarities between neonates, young adults, and older adults, with an unexpectedly small number of genes exhibiting statistically significant age-dependent differences. By examining the differentially induced genes in the context of transcription factor binding motifs and RNA-seq data sets from mutant mouse strains, a previously described deficiency in interferon response factor-3 activity could be implicated in most of the differences between newborns and young adults. Contrary to these observations, older adults exhibited elevated expression of inflammatory genes at baseline, yet the responses following stimulation correlated more closely with those observed in younger adults. Notably, major differences in the expression of constitutively expressed genes were not observed, suggesting that the age-related differences are driven by environmental influences rather than cell-autonomous differences in monocyte development. PMID:26147648

  15. [The existence vomeronasal organ in adult humans].

    PubMed

    Rapiejko, Piotr; Zielnik-Jurkiewicz, Beata; Wojdas, Andrzej; Ratajczak, Jan; Jurkiewicz, Dariusz

    2007-01-01

    The influence of chemical substances (feromones) on human emotional and physical condition has fascinated psychologists, sexuologists and laryngologists since centurie. Literature conveys inconsistent information on vomeronasal organ (VNO) occurrence in humans. This organ is often called Jacobson's, and 2 symmetrical openings leading into it, located on both sides of septum, are called Ruyasch's ducts. The aim of the study was to analyze vomeronasal organ occurrence in humans in relation to age and sex. The study was conducted in a group of 634 patients, aged 18-80 years. All patients underwent routine ENT examination including rhinoscopy, nasal cavity examination with usage of 2.5x magnification lens (surgical glasses) and surgical microscope with 10x magnification. All persons had nasal cavities examined endoscopically. Every time presence of vomeronasal organ openings, along with localization, size and symmetry of these was noted. Subjects, who presented Jacobson's organ, were asked to fill a questionnaire concerning influence of smells on erotic sensations. Vomeronasal organ was fund in 312 persons, that is 49.21%. In 83.65% of cases vomeronasal organ opening size was smaller than 0.2 mm, what restricted its visibility to usage of magnifying lens, microscope, or endoscope. In 16.34% of cases only vomeronasal organ ducts openings were well visible in routine rhinoscopy without magnification. Vomeronasal organ was found more often in men than women. VNO was significantly more rare in patients with nasal septal deviation. In these cases, vomeronasal organ was usually found unilaterally, in all the cases on the concave side of deviated nasal septum. PMID:18260256

  16. Conversion of ICRP male reference phantom to polygon-surface phantom

    NASA Astrophysics Data System (ADS)

    Yeom, Yeon Soo; Han, Min Cheol; Kim, Chan Hyeong; Jeong, Jong Hwi

    2013-10-01

    The International Commission on Radiological Protection (ICRP) reference phantoms, developed based on computed tomography images of human bodies, provide much more realism of human anatomy than the previously used MIRD5 (Medical Internal Radiation Dose) mathematical phantoms. It has been, however, realized that the ICRP reference phantoms have some critical limitations showing a considerable amount of holes for the skin and wall organs mainly due to the nature of voxels of which the phantoms are made, especially due to their low voxel resolutions. To address this problem, we are planning to develop the polygon-surface version of ICRP reference phantoms by directly converting the ICRP reference phantoms (voxel phantoms) to polygon-surface phantoms. The objective of this preliminary study is to see if it is indeed possible to construct the high-quality polygon-surface phantoms based on the ICRP reference phantoms maintaining identical organ morphology and also to identify any potential issues, and technologies to address these issues, in advance. For this purpose, in the present study, the ICRP reference male phantom was roughly converted to a polygon-surface phantom. Then, the constructed phantom was implemented in Geant4, Monte Carlo particle transport code, for dose calculations, and the calculated dose values were compared with those of the original ICRP reference phantom to see how much the calculated dose values are sensitive to the accuracy of the conversion process. The results of the present study show that it is certainly possible to convert the ICRP reference phantoms to surface phantoms with enough accuracy. In spite of using relatively less resources (<2 man-months), we were able to construct the polygon-surface phantom with the organ masses perfectly matching the ICRP reference values. The analysis of the calculated dose values also implies that the dose values are indeed not very sensitive to the detailed morphology of the organ models in the phantom

  17. Expansion of Multipotent Stem Cells from the Adult Human Brain

    PubMed Central

    Murrell, Wayne; Palmero, Emily; Bianco, John; Stangeland, Biljana; Joel, Mrinal; Paulson, Linda; Thiede, Bernd; Grieg, Zanina; Ramsnes, Ingunn; Skjellegrind, Håvard K.; Nygård, Ståle; Brandal, Petter; Sandberg, Cecilie; Vik-Mo, Einar; Palmero, Sheryl; Langmoen, Iver A.

    2013-01-01

    The discovery of stem cells in the adult human brain has revealed new possible scenarios for treatment of the sick or injured brain. Both clinical use of and preclinical research on human adult neural stem cells have, however, been seriously hampered by the fact that it has been impossible to passage these cells more than a very few times and with little expansion of cell numbers. Having explored a number of alternative culturing conditions we here present an efficient method for the establishment and propagation of human brain stem cells from whatever brain tissue samples we have tried. We describe virtually unlimited expansion of an authentic stem cell phenotype. Pluripotency proteins Sox2 and Oct4 are expressed without artificial induction. For the first time multipotency of adult human brain-derived stem cells is demonstrated beyond tissue boundaries. We characterize these cells in detail in vitro including microarray and proteomic approaches. Whilst clarification of these cells’ behavior is ongoing, results so far portend well for the future repair of tissues by transplantation of an adult patient’s own-derived stem cells. PMID:23967194

  18. Phantom Crossing DGP Gravity

    SciTech Connect

    Hirano, Koichi; Komiya, Zen

    2010-08-12

    We propose a phantom crossing Dvali-Gabadadze-Porrati (DGP) model. In our model, the effective equation of state of the DGP gravity crosses the phantom divide line. We demonstrate crossing of the phantom divide does not occur within the framework of the original DGP model or the DGP model developed by Dvali and Turner. By extending their model, we construct a model that realizes crossing of the phantom divide. DGP models can account for late-time acceleration of the universe without dark energy. Phantom Crossing DGP model is more compatible with recent observational data from Type Ia Supernovae (SNIa), Cosmic Microwave Background (CMB) anisotropies, and Baryon Acoustic Oscillations (BAO) than the original DGP model or the DGP model developed by Dvali and Turner.

  19. Hybrid computational phantoms of the 15-year male and female adolescent: Applications to CT organ dosimetry for patients of variable morphometry

    SciTech Connect

    Lee, Choonsik; Lodwick, Daniel; Williams, Jonathan L.; Bolch, Wesley E.

    2008-06-15

    Currently, two classes of the computational phantoms have been developed for dosimetry calculation: (1) stylized (or mathematical) and (2) voxel (or tomographic) phantoms describing human anatomy through mathematical surface equations and three-dimensional labeled voxel matrices, respectively. Mathematical surface equations in stylized phantoms provide flexibility in phantom design and alteration, but the resulting anatomical description is, in many cases, not very realistic. Voxel phantoms display far better anatomical realism, but they are limited in terms of their ability to alter organ shape, position, and depth, as well as body posture. A new class of computational phantoms - called hybrid phantoms - takes advantage of the best features of stylized and voxel phantoms - flexibility and anatomical realism, respectively. In the current study, hybrid computational phantoms representing reference 15-year male and female body anatomy and anthropometry are presented. For the male phantom, organ contours were extracted from the University of Florida (UF) 14-year series B male voxel phantom, while for the female phantom, original computed tomography (CT) data from two 14-year female patients were used. Polygon mesh models for the major organs and tissues were reconstructed for nonuniform rational B-spline (NURBS) surface modeling. The resulting NURBS/polygon mesh models representing body contour and internal anatomy were matched to anthropometric data and reference organ mass data provided by the Centers for Disease Control and Prevention (CDC) and the International Commission on Radiation Protection (ICRP), respectively. Finally, two hybrid 15-year male and female phantoms were completed where a total of eight anthropometric data categories were matched to standard values within 4% and organ masses matched to ICRP data within 1% with the exception of total skin. To highlight the flexibility of the hybrid phantoms, 10th and 90th weight percentile 15-year male and

  20. Assessment of individual organ doses in a realistic human phantom from neutron and gamma stimulated spectroscopy of the breast and liver

    PubMed Central

    Belley, Matthew D.; Segars, William Paul; Kapadia, Anuj J.

    2014-01-01

    Purpose: Understanding the radiation dose to a patient is essential when considering the use of an ionizing diagnostic imaging test for clinical diagnosis and screening. Using Monte Carlo simulations, the authors estimated the three-dimensional organ-dose distribution from neutron and gamma irradiation of the male liver, female liver, and female breasts for neutron- and gamma-stimulated spectroscopic imaging. Methods: Monte Carlo simulations were developed using the Geant4 GATE application and a voxelized XCAT human phantom. A male and a female whole body XCAT phantom was voxelized into 256 × 256 × 600 voxels (3.125 × 3.125 × 3.125 mm3). A monoenergetic rectangular beam of 5.0 MeV neutrons or 7.0 MeV photons was made incident on a 2 cm thick slice of the phantom. The beam was rotated at eight different angles around the phantom ranging from 0° to 180°. Absorbed dose was calculated for each individual organ in the body and dose volume histograms were computed to analyze the absolute and relative doses in each organ. Results: The neutron irradiations of the liver showed the highest organ dose absorption in the liver, with appreciably lower doses in other proximal organs. The dose distribution within the irradiated slice exhibited substantial attenuation with increasing depth along the beam path, attenuating to ∼15% of the maximum value at the beam exit side. The gamma irradiation of the liver imparted the highest organ dose to the stomach wall. The dose distribution from the gammas showed a region of dose buildup at the beam entrance, followed by a relatively uniform dose distribution to all of the deep tissue structures, attenuating to ∼75% of the maximum value at the beam exit side. For the breast scans, both the neutron and gamma irradiation registered maximum organ doses in the breasts, with all other organs receiving less than 1% of the breast dose. Effective doses ranged from 0.22 to 0.37 mSv for the neutron scans and 41 to 66 mSv for the gamma scans

  1. Assessment of individual organ doses in a realistic human phantom from neutron and gamma stimulated spectroscopy of the breast and liver

    SciTech Connect

    Belley, Matthew D.; Segars, William Paul; Kapadia, Anuj J.

    2014-06-15

    Purpose: Understanding the radiation dose to a patient is essential when considering the use of an ionizing diagnostic imaging test for clinical diagnosis and screening. Using Monte Carlo simulations, the authors estimated the three-dimensional organ-dose distribution from neutron and gamma irradiation of the male liver, female liver, and female breasts for neutron- and gamma-stimulated spectroscopic imaging. Methods: Monte Carlo simulations were developed using the Geant4 GATE application and a voxelized XCAT human phantom. A male and a female whole body XCAT phantom was voxelized into 256 × 256 × 600 voxels (3.125 × 3.125 × 3.125 mm{sup 3}). A monoenergetic rectangular beam of 5.0 MeV neutrons or 7.0 MeV photons was made incident on a 2 cm thick slice of the phantom. The beam was rotated at eight different angles around the phantom ranging from 0° to 180°. Absorbed dose was calculated for each individual organ in the body and dose volume histograms were computed to analyze the absolute and relative doses in each organ. Results: The neutron irradiations of the liver showed the highest organ dose absorption in the liver, with appreciably lower doses in other proximal organs. The dose distribution within the irradiated slice exhibited substantial attenuation with increasing depth along the beam path, attenuating to ∼15% of the maximum value at the beam exit side. The gamma irradiation of the liver imparted the highest organ dose to the stomach wall. The dose distribution from the gammas showed a region of dose buildup at the beam entrance, followed by a relatively uniform dose distribution to all of the deep tissue structures, attenuating to ∼75% of the maximum value at the beam exit side. For the breast scans, both the neutron and gamma irradiation registered maximum organ doses in the breasts, with all other organs receiving less than 1% of the breast dose. Effective doses ranged from 0.22 to 0.37 mSv for the neutron scans and 41 to 66 mSv for the gamma

  2. Monte Carlo simulations in multi-detector CT (MDCT) for two PET/CT scanner models using MASH and FASH adult phantoms

    NASA Astrophysics Data System (ADS)

    Belinato, W.; Santos, W. S.; Paschoal, C. M. M.; Souza, D. N.

    2015-06-01

    The combination of positron emission tomography (PET) and computed tomography (CT) has been extensively used in oncology for diagnosis and staging of tumors, radiotherapy planning and follow-up of patients with cancer, as well as in cardiology and neurology. This study determines by the Monte Carlo method the internal organ dose deposition for computational phantoms created by multidetector CT (MDCT) beams of two PET/CT devices operating with different parameters. The different MDCT beam parameters were largely related to the total filtration that provides a beam energetic change inside the gantry. This parameter was determined experimentally with the Accu-Gold Radcal measurement system. The experimental values of the total filtration were included in the simulations of two MCNPX code scenarios. The absorbed organ doses obtained in MASH and FASH phantoms indicate that bowtie filter geometry and the energy of the X-ray beam have significant influence on the results, although this influence can be compensated by adjusting other variables such as the tube current-time product (mAs) and pitch during PET/CT procedures.

  3. Human pancreatic polypeptide in children and young adults.

    PubMed

    Hanukoglu, A; Chalew, S; Kowarski, A A

    1990-01-01

    Measurement of human pancreatic polypeptide may be useful for assessment of gastrointestinal function, integrity of the parasympathetic nervous system or screening for endocrine neoplasia. In adults hPP levels have been reported to increase with age. However hPP levels throughout childhood have not been well characterized in comparison with the adult range. We studied fasting human pancreatic polypeptide (hPP) from 45 pediatric patients, from infancy - 15 years, and 18 older adolescents and adults aged 16-45 years. The mean hPP level of children (233 +/- 147 pg/ml) was significantly higher than that (113 +/- 35 pg/ml) of adults (P less than .0001). There was no difference in mean hPP levels of children with normal growth hormone secretion compared to growth hormone deficient patients. There was no effect of gender or body mass index on hPP levels. We conclude that fasting hPP levels must be interpreted with respect to the age of the subject, children particularly, in that preteens may have higher fasting levels than older teenagers and adults.

  4. Human pancreatic polypeptide in children and young adults.

    PubMed

    Hanukoglu, A; Chalew, S; Kowarski, A A

    1990-01-01

    Measurement of human pancreatic polypeptide may be useful for assessment of gastrointestinal function, integrity of the parasympathetic nervous system or screening for endocrine neoplasia. In adults hPP levels have been reported to increase with age. However hPP levels throughout childhood have not been well characterized in comparison with the adult range. We studied fasting human pancreatic polypeptide (hPP) from 45 pediatric patients, from infancy - 15 years, and 18 older adolescents and adults aged 16-45 years. The mean hPP level of children (233 +/- 147 pg/ml) was significantly higher than that (113 +/- 35 pg/ml) of adults (P less than .0001). There was no difference in mean hPP levels of children with normal growth hormone secretion compared to growth hormone deficient patients. There was no effect of gender or body mass index on hPP levels. We conclude that fasting hPP levels must be interpreted with respect to the age of the subject, children particularly, in that preteens may have higher fasting levels than older teenagers and adults. PMID:2307392

  5. Predictors of food preferences in adult humans.

    PubMed

    Logue, A W; Smith, M E

    1986-06-01

    Predictors of preferences for a wide variety of foods were examined in 303 male and female human subjects ranging from 14-68 years of age. The subjects completed questionnaires which requested information on the subject's sex, age, thinness, sensation seeking and ethnic background, as well as on the subjects' food preferences. Largely consistent with previous studies, female subjects reported higher preferences for low-calorie foods, candy and wine, and lower preferences for meat, beer, spicy foods and milk. Younger subjects reported higher preferences for sweet foods and lower preferences for foods such as chili pepper that are considered acquired tastes. Thinner subjects tended to rate both sweet foods and meat lower than did other subjects. Preferences for spicy foods or foods likely to cause illness were positively correlated with sensation seeking while preferences for sweet or bland foods or foods unlikely to cause illness were negatively correlated with sensation seeking. Subjects for whom the primary cuisine on which they were raised was Oriental cuisine preferred alcoholic beverages and non-Oriental foods less than did other subjects. A factor analysis of the food preferences yielded ten factors including those for meat and potatoes, alcohol, spices and junk food. Data on predictors of food preferences can assist research on the determinants of food preferences, however much of the variance in food preferences remains to be explained.

  6. Human Adult Cortical Reorganization and Consequent Visual Distortion

    PubMed Central

    Dilks, Daniel D.; Serences, John T.; Rosenau, Benjamin J.; Yantis, Steven; McCloskey, Michael

    2009-01-01

    Neural and behavioral evidence for cortical reorganization in the adult somatosensory system after loss of sensory input (e.g., amputation) has been well documented. In contrast, evidence for reorganization in the adult visual system is far less clear: neural evidence is the subject of controversy, behavioral evidence is sparse, and studies combining neural and behavioral evidence have not previously been reported. Here, we report converging behavioral and neuroimaging evidence from a stroke patient (B.L.) in support of cortical reorganization in the adult human visual system. B.L.’s stroke spared the primary visual cortex (V1), but destroyed fibers that normally provide input to V1 from the upper left visual field (LVF). As a consequence, B.L. is blind in the upper LVF, and exhibits distorted perception in the lower LVF: stimuli appear vertically elongated, toward and into the blind upper LVF. For example, a square presented in the lower LVF is perceived as a rectangle extending upward. We hypothesized that the perceptual distortion was a consequence of cortical reorganization in V1. Extensive behavioral testing supported our hypothesis, and functional magnetic resonance imaging (fMRI) confirmed V1 reorganization. Together, the behavioral and fMRI data show that loss of input to V1 after a stroke leads to cortical reorganization in the adult human visual system, and provide the first evidence that reorganization of the adult visual system affects visual perception. These findings contribute to our understanding of the human adult brain’s capacity to change and has implications for topics ranging from learning to recovery from brain damage. PMID:17804619

  7. SU-E-T-117: Dose to Organs Outside of CT Scan Range- Monte Carlo and Hybrid Phantom Approach

    SciTech Connect

    Pelletier, C; Jung, J; Lee, C; Kim, J; Lee, C

    2014-06-01

    Purpose: Epidemiological study of second cancer risk for cancer survivors often requires the dose to normal tissues located outside the anatomy covered by radiological imaging, which is usually limited to tumor and organs at risk. We have investigated the feasibility of using whole body computational human phantoms for estimating out-of-field organ doses for patients treated by Intensity Modulated Radiation Therapy (IMRT). Methods: Identical 7-field IMRT prostate plans were performed using X-ray Voxel Monte Carlo (XVMC), a radiotherapy-specific Monte Carlo transport code, on the computed tomography (CT) images of the torso of an adult male patient (175 cm height, 66 kg weight) and an adult male hybrid computational phantom with the equivalent body size. Dose to the liver, right lung, and left lung were calculated and compared. Results: Considerable differences are seen between the doses calculated by XVMC for the patient CT and the hybrid phantom. One major contributing factor is the treatment method, deep inspiration breath hold (DIBH), used for this patient. This leads to significant differences in the organ position relative to the treatment isocenter. The transverse distances from the treatment isocenter to the inferior border of the liver, left lung, and right lung are 19.5cm, 29.5cm, and 30.0cm, respectively for the patient CT, compared with 24.3cm, 36.6cm, and 39.1cm, respectively, for the hybrid phantom. When corrected for the distance, the mean doses calculated using the hybrid phantom are within 28% of those calculated using the patient CT. Conclusion: This study showed that mean dose to the organs located in the missing CT coverage can be reconstructed by using whole body computational human phantoms within reasonable dosimetric uncertainty, however appropriate corrections may be necessary if the patient is treated with a technique that will significantly deform the size or location of the organs relative to the hybrid phantom.

  8. Lung pair phantom

    DOEpatents

    Olsen, P.C.; Gordon, N.R.; Simmons, K.L.

    1993-11-30

    The present invention is a material and method of making the material that exhibits improved radiation attenuation simulation of real lungs, i.e., an ``authentic lung tissue`` or ALT phantom. Specifically, the ALT phantom is a two-part polyurethane medium density foam mixed with calcium carbonate, potassium carbonate if needed for K-40 background, lanthanum nitrate, acetone, and a nitrate or chloride form of a radionuclide. This formulation is found to closely match chemical composition and linear attenuation of real lungs. The ALT phantom material is made according to established procedures but without adding foaming agents or preparing thixotropic concentrate and with a modification for ensuring uniformity of density of the ALT phantom that is necessary for accurate simulation. The modification is that the polyurethane chemicals are mixed at a low temperature prior to pouring the polyurethane mixture into the mold.

  9. Lung pair phantom

    DOEpatents

    Olsen, Peter C.; Gordon, N. Ross; Simmons, Kevin L.

    1993-01-01

    The present invention is a material and method of making the material that exhibits improved radiation attenuation simulation of real lungs, i.e., an "authentic lung tissue" or ALT phantom. Specifically, the ALT phantom is a two-part polyurethane medium density foam mixed with calcium carbonate, potassium carbonate if needed for K-40 background, lanthanum nitrate, acetone, and a nitrate or chloride form of a radionuclide. This formulation is found to closely match chemical composition and linear attenuation of real lungs. The ALT phantom material is made according to established procedures but without adding foaming agents or preparing thixotropic concentrate and with a modification for ensuring uniformity of density of the ALT phantom that is necessary for accurate simulation. The modification is that the polyurethane chemicals are mixed at a low temperature prior to pouring the polyurethane mixture into the mold.

  10. Ultrastructural characteristics of human adult and infant cerebral cortical neurons.

    PubMed Central

    Ong, W Y; Garey, L J

    1991-01-01

    Biopsy specimens of human cerebral cortex from three adults and two infants were studied by correlating their light microscopic features in semithin sections with their ultrastructural characteristics. There was good tissue preservation, due to a minimum delay between obtaining the specimens and fixation. Pyramidal cells had a prominent apical dendrite, fine heterochromatin clumps in the nucleus and generally small numbers of cytoplasmic organelles, except for numerous free ribosomes in some of the large pyramids of Layers III to VI. Non-pyramidal cells lacked an apical dendrite and were further classified, on size and ultrastructure, into small, medium and large types. Large numbers of asymmetrical and symmetrical synapses were present in the neuropil but very few axosomatic synapses were found in the human cerebral cortex compared with subhuman primates and other mammals. Some symmetrical synapses were characterised by the presence of wide pre- and postsynaptic densities. The same general features of the adult cortex were also encountered in the infant, with certain exceptions. Many of the infant neurons had less densely packed heterochromatin, but greater numbers of free ribosomes, compared with the adult, and lipofuscin was absent. There was a total absence of myelinated fibres from the infant cortex; more large diameter dendrites were present than in the adult and axosomatic synapses were commoner. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 11 Fig. 12 Fig. 13 Fig. 14 Fig. 15 PMID:2050578

  11. [Generation of new nerve cells in the adult human brain].

    PubMed

    Poulsen, Frantz Rom; Meyer, Morten; Rasmussen, Jens Zimmer

    2003-03-31

    Generation of new nerve cells (neurogenesis) is normally considered to be limited to the fetal and early postnatal period. Thus, damaged nerve cells are not expected to be replaced by generation of new cells. The brain is, however, more plastic than previously assumed. This also includes neurogenesis in the adult human brain. In particular two brain regions show continuous division of neural stem and progenitor cells generating neurons and glial cells, namely the subgranular zone of the dentate gyrus and the subventricular zones of the lateral ventricles. From the latter region newly generated neuroblasts (immature nerve cells) migrate toward the olfactory bulb where they differentiate into neurons. In the dentate gyrus the newly generated neurons become functionally integrated in the granule cell layer, where they are believed to be of importance to learning and memory. It is at present not known whether neurogenesis in the adult human brain can be manipulated for specific repair after brain damage.

  12. Stability of phantom wormholes

    SciTech Connect

    Lobo, Francisco S.N.

    2005-06-15

    It has recently been shown that traversable wormholes may be supported by phantom energy. In this work phantom wormhole geometries are modeled by matching an interior traversable wormhole solution, governed by the equation of state p={omega}{rho} with {omega}<-1, to an exterior vacuum spacetime at a finite junction interface. The stability analysis of these phantom wormholes to linearized spherically symmetric perturbations about static equilibrium solutions is carried out. A master equation dictating the stability regions is deduced, and by separating the cases of a positive and a negative surface energy density, it is found that the respective stable equilibrium configurations may be increased by strategically varying the wormhole throat radius. The first model considered, in the absence of a thin shell, is that of an asymptotically flat phantom wormhole spacetime. The second model constructed is that of an isotropic pressure phantom wormhole, which is of particular interest, as the notion of phantom energy is that of a spatially homogeneous cosmic fluid, although it may be extended to inhomogeneous spherically symmetric spacetimes.

  13. Quantum phantom cosmology

    SciTech Connect

    DaPbrowski, Mariusz P.; Kiefer, Claus; Sandhoefer, Barbara

    2006-08-15

    We apply the formalism of quantum cosmology to models containing a phantom field. Three models are discussed explicitly: a toy model, a model with an exponential phantom potential, and a model with phantom field accompanied by a negative cosmological constant. In all these cases we calculate the classical trajectories in configuration space and give solutions to the Wheeler-DeWitt equation in quantum cosmology. In the cases of the toy model and the model with exponential potential we are able to solve the Wheeler-DeWitt equation exactly. For comparison, we also give the corresponding solutions for an ordinary scalar field. We discuss, in particular, the behavior of wave packets in minisuperspace. For the phantom field these packets disperse in the region that corresponds to the big-rip singularity. This thus constitutes a genuine quantum region at large scales, described by a regular solution of the Wheeler-DeWitt equation. For the ordinary scalar field, the big-bang singularity is avoided. Some remarks on the arrow of time in phantom models as well as on the relation of phantom models to loop quantum cosmology are given.

  14. A human-phantom coupling experiment and a dispersive simulation model for investigating the variation of dielectric properties of biological tissues.

    PubMed

    Gomez-Tames, Jose; Fukuhara, Yuto; He, Siyu; Saito, Kazuyuki; Ito, Koichi; Yu, Wenwei

    2015-06-01

    Variation of the dielectric properties of tissues could happen due to aging, moisture of the skin, muscle denervation, and variation of blood flow by temperature. Several studies used burst-modulated alternating stimulation to improve activation and comfort by reducing tissue impedance as a possible mechanism to generate muscle activation with less energy. The study of the effect of dielectric properties of biological tissues in nerve activation presents a fundamental problem, which is the difficulty of systematically changing the morphological factors and dielectric properties of the subjects under study. We tackle this problem by using a simulation and an experimental study. The experimental study is a novel method that combines a fat tissue-equivalent phantom, with known and adjustable dielectric properties, with the human thigh. In this way, the dispersion of the tissue under study could be modified to observe its effects systematically in muscle activation. We observed that, to generate a given amount of muscle or nerve activation under conditions of decreased impedance, the magnitude of the current needs to be increased while the magnitude of the voltage needs to be decreased.

  15. Studies on heavy charged particle interaction, water equivalence and Monte Carlo simulation in some gel dosimeters, water, human tissues and water phantoms

    NASA Astrophysics Data System (ADS)

    Kurudirek, Murat

    2015-09-01

    Some gel dosimeters, water, human tissues and water phantoms were investigated with respect to their radiological properties in the energy region 10 keV-10 MeV. The effective atomic numbers (Zeff) and electron densities (Ne) for some heavy charged particles such as protons, He ions, B ions and C ions have been calculated for the first time for Fricke, MAGIC, MAGAT, PAGAT, PRESAGE, water, adipose tissue, muscle skeletal (ICRP), muscle striated (ICRU), plastic water, WT1 and RW3 using mass stopping powers from SRIM Monte Carlo software. The ranges and straggling were also calculated for the given materials. Two different set of mass stopping powers were used to calculate Zeff for comparison. The water equivalence of the given materials was also determined based on the results obtained. The Monte Carlo simulation of the charged particle transport was also done using SRIM code. The heavy ion distribution along with its parameters were shown for the given materials for different heavy ions. Also the energy loss and damage events in water when irradiated with 100 keV heavy ions were studied in detail.

  16. Epidermal growth factor receptor in adult human dorsal root ganglia.

    PubMed

    Huerta, J J; Diaz-Trelles, R; Naves, F J; Llamosas, M M; Del Valle, M E; Vega, J A

    1996-09-01

    Transforming growth factor-alpha (TGFalpha) enhances neuronal survival and neurite outgrowth in cultured dorsal root ganglia (DRG) sensory neurons. It binds a membrane protein, denominated epidermal growth factor receptor (EGFr). EGFr has been localized in developing and adult human DRG. However, it remains to be elucidated whether all DRG neurons express EGFr or whether differences exist among neuronal subtypes. This study was undertaken to investigate these topics in adult human DRG using immunoblotting, and combined immunohistochemistry and image analysis techniques. A mouse monoclonal antibody (clone F4) mapping within the intracytoplasmic domain of EGFr was used. Immunoblotting revealed two main proteins with estimated molecular masses of approximately/equal to 65 kDa and 170 kDa, and thus consistent with the full-length EGFr. Additional protein bands were also encountered. Light immunohistochemistry revealed specific immunoreactivity (IR) for EGFr-like proteins in most (86%) primary sensory neurons, the intensity of immunostaining being stronger in the small- and intermediate-sized ones. Furthermore, EGFr-like IR was also observed in the satellite glial cells of the ganglia as well as in the intraganglionic and dorsal root Schwann cells. Taken together, our findings demonstrate that EGFr, and other related proteins containing the epitope labeled with the antibody F4, are responsible for the EGFr IR reported in DRG. Furthermore, we demonstrated heterogeneity in the expression of EGFr-like IR in adult human primary sensory neurons, which suggests different responsiveness to their ligands.

  17. Phantom energy traversable wormholes

    SciTech Connect

    Lobo, Francisco S.N.

    2005-04-15

    It has been suggested that a possible candidate for the present accelerated expansion of the Universe is 'phantom energy'. The latter possesses an equation of state of the form {omega}{identical_to}p/{rho}<-1, consequently violating the null energy condition. As this is the fundamental ingredient to sustain traversable wormholes, this cosmic fluid presents us with a natural scenario for the existence of these exotic geometries. 'Note, however, that the notion of phantom energy is that of a homogeneously distributed fluid. Nevertheless, it can be extended to inhomogeneous spherically symmetric spacetimes, and it is shown that traversable wormholes may be supported by phantom energy. Because of the fact of the accelerating Universe, macroscopic wormholes could naturally be grown from the submicroscopic constructions that originally pervaded the quantum foam. One could also imagine an advanced civilization mining the cosmic fluid for phantom energy necessary to construct and sustain a traversable wormhole. In this context, we investigate the physical properties and characteristics of traversable wormholes constructed using the equation of state p={omega}{rho}, with {omega}<-1. We analyze specific wormhole geometries, considering asymptotically flat spacetimes and imposing an isotropic pressure. We also construct a thin shell around the interior wormhole solution, by imposing the phantom energy equation of state on the surface stresses. Using the 'volume integral quantifier' we verify that it is theoretically possible to construct these geometries with vanishing amounts of averaged null energy condition violating phantom energy. Specific wormhole dimensions and the traversal velocity and time are also deduced from the traversability conditions for a particular wormhole geometry. These phantom energy traversable wormholes have far-reaching physical and cosmological implications. For instance, an advanced civilization may use these geometries to induce closed timelike

  18. VOXMAT: Hybrid Computational Phantom for Dose Assessment

    SciTech Connect

    Akkurt, Hatice; Eckerman, Keith F

    2007-01-01

    The Oak Ridge National Laboratory (ORNL) computational phantoms have been the standard for assessing the radiation dose due to internal and external exposure over the past three decades. In these phantoms, the body surface and each organ are approximated by mathematical equations; hence, some of the organs are not necessarily realistic in their shape. Over the past two decades, these phantoms have been revised and updated: some of the missing internal organs have been added and the locations of the existing organs have been revised (e.g., thyroid). In the original phantom, only three elemental compositions were used to describe all body tissues. Recently, the compositions of the organs have been updated based on ICRP-89 standards. During the past decade, phantoms based on CT scans were developed for use in dose assessment. Although their shapes are realistic, some computational challenges are noted; including increased computational times and increased memory requirements. For good spatial resolution, more than several million voxels are used to represent the human body. Moreover, when CT scans are obtained, the subject is in a supine position with arms at the side. In some occupational exposure cases, it is necessary to evaluate the dose with the arms and legs in different positions. It will be very difficult and inefficient to reposition the voxels defining the arms and legs to simulate these exposure geometries. In this paper, a new approach for computational phantom development is presented. This approach utilizes the combination of a mathematical phantom and a voxelized phantom for the representation of the anatomy.

  19. Development of Chinese reference man deformable surface phantom and its application to the influence of physique on electromagnetic dosimetry

    NASA Astrophysics Data System (ADS)

    Yu, D.; Wang, M.; Liu, Q.

    2015-09-01

    A reference man is a theoretical individual that represents the average anatomical structure and physiological and metabolic features of a specific group of people and has been widely used in radiation safety research. With the help of an advantage in deformation, the present work proposed a Chinese reference man adult-male polygon-mesh surface phantom based on the Visible Chinese Human segment image dataset by surface rendering and deforming. To investigate the influence of physique on electromagnetic dosimetry in humans, a series of human phantoms with 10th, 50th and 90th body mass index and body circumference percentile physiques for Chinese adult males were further constructed by deforming the Chinese reference man surface phantom. All the surface phantoms were then voxelized to perform electromagnetic field simulation in a frequency range of 20 MHz to 3 GHz using the finite-difference time-domain method and evaluate the whole-body average and organ average specific absorption rate and the ratios of absorbed energy in skin, fat and muscle to the whole body. The results indicate thinner physique leads to higher WBSAR and the volume of subcutaneous fat, the penetration depth of the electromagnetic field in tissues and standing-wave occurrence may be the influence factors of physique on electromagnetic dosimetry.

  20. Development of Chinese reference man deformable surface phantom and its application to the influence of physique on electromagnetic dosimetry.

    PubMed

    Yu, D; Wang, M; Liu, Q

    2015-09-01

    A reference man is a theoretical individual that represents the average anatomical structure and physiological and metabolic features of a specific group of people and has been widely used in radiation safety research. With the help of an advantage in deformation, the present work proposed a Chinese reference man adult-male polygon-mesh surface phantom based on the Visible Chinese Human segment image dataset by surface rendering and deforming. To investigate the influence of physique on electromagnetic dosimetry in humans, a series of human phantoms with 10th, 50th and 90th body mass index and body circumference percentile physiques for Chinese adult males were further constructed by deforming the Chinese reference man surface phantom. All the surface phantoms were then voxelized to perform electromagnetic field simulation in a frequency range of 20 MHz to 3 GHz using the finite-difference time-domain method and evaluate the whole-body average and organ average specific absorption rate and the ratios of absorbed energy in skin, fat and muscle to the whole body. The results indicate thinner physique leads to higher WBSAR and the volume of subcutaneous fat, the penetration depth of the electromagnetic field in tissues and standing-wave occurrence may be the influence factors of physique on electromagnetic dosimetry.

  1. Development of Chinese reference man deformable surface phantom and its application to the influence of physique on electromagnetic dosimetry.

    PubMed

    Yu, D; Wang, M; Liu, Q

    2015-09-01

    A reference man is a theoretical individual that represents the average anatomical structure and physiological and metabolic features of a specific group of people and has been widely used in radiation safety research. With the help of an advantage in deformation, the present work proposed a Chinese reference man adult-male polygon-mesh surface phantom based on the Visible Chinese Human segment image dataset by surface rendering and deforming. To investigate the influence of physique on electromagnetic dosimetry in humans, a series of human phantoms with 10th, 50th and 90th body mass index and body circumference percentile physiques for Chinese adult males were further constructed by deforming the Chinese reference man surface phantom. All the surface phantoms were then voxelized to perform electromagnetic field simulation in a frequency range of 20 MHz to 3 GHz using the finite-difference time-domain method and evaluate the whole-body average and organ average specific absorption rate and the ratios of absorbed energy in skin, fat and muscle to the whole body. The results indicate thinner physique leads to higher WBSAR and the volume of subcutaneous fat, the penetration depth of the electromagnetic field in tissues and standing-wave occurrence may be the influence factors of physique on electromagnetic dosimetry. PMID:26301501

  2. [Multipotency of adult stem cells derived from human amnion].

    PubMed

    Shi, Mingxia; Li, Weijia; Li, Bingzong; Li, Jing; Zhao, Chunhua

    2009-05-01

    Adult stem cells are drawing more and more attention due to the potential application in degenerative medicine without posing any moral problem. There is growing evidence showing that the human amnion contains various types of adult stem cell. Since amniotic tissue is readily available, it has the potential to be an important source of regenerative medicine material. In this study we tried to find multipotent adult stem cells in human amnion. We isolated stem cells from amniotic mesenchymal cells by limiting dilution assay. Similar to bone marrow derived mesenchymal stem cells, these cells displayed a fibroblast like appearance. They were positive for CD105, CD29, CD44, negative for haematopoietic (GlyA, CD31, CD34, CD45) and epithelial cell (pan-CK) markers. These stem cells had the potential to differentiate not only into osteogenic, adipogenic and endothelial lineages, but also hepatocyte-like cells and neural cells at the single-cell level depending on the culture conditions. They had the capacity for self-renewal and multilineage differentiation even after being expanded for more than 30 population doublings in vitro. So they may be an ideal stem cell source for inherited or degenerative diseases treatment.

  3. How long have adult humans been consuming milk?

    PubMed

    Gerbault, Pascale; Roffet-Salque, Mélanie; Evershed, Richard P; Thomas, Mark G

    2013-12-01

    Lactase is the enzyme that breaks down the milk sugar lactose, and in most mammals, including most humans, lactase activity is down-regulated after the weaning period is completed. However, in about 35% of adults worldwide, lactase continues to be expressed throughout adulthood, a feature termed lactase persistence (LP). Genetic evidence indicates that LP is a recent human adaptation, and its current geographic distribution correlates with the relative historical importance of dairying in different human populations. Investigating archaeological evidence for fresh milk consumption has proved crucial in building an account of the joint evolution of LP and dairying. A powerful technique for investigating food processing, including milk processing, in ancient populations is lipid residue analysis on archaeological pottery. We review here the archaeological and genetic evidence available that have contributed to a better understanding of the gene-culture co-evolution of LP and dairying. PMID:24339181

  4. How long have adult humans been consuming milk?

    PubMed

    Gerbault, Pascale; Roffet-Salque, Mélanie; Evershed, Richard P; Thomas, Mark G

    2013-12-01

    Lactase is the enzyme that breaks down the milk sugar lactose, and in most mammals, including most humans, lactase activity is down-regulated after the weaning period is completed. However, in about 35% of adults worldwide, lactase continues to be expressed throughout adulthood, a feature termed lactase persistence (LP). Genetic evidence indicates that LP is a recent human adaptation, and its current geographic distribution correlates with the relative historical importance of dairying in different human populations. Investigating archaeological evidence for fresh milk consumption has proved crucial in building an account of the joint evolution of LP and dairying. A powerful technique for investigating food processing, including milk processing, in ancient populations is lipid residue analysis on archaeological pottery. We review here the archaeological and genetic evidence available that have contributed to a better understanding of the gene-culture co-evolution of LP and dairying.

  5. Neurons in the White Matter of the Adult Human Neocortex

    PubMed Central

    Suárez-Solá, M. Luisa; González-Delgado, Francisco J.; Pueyo-Morlans, Mercedes; Medina-Bolívar, O. Carolina; Hernández-Acosta, N. Carolina; González-Gómez, Miriam; Meyer, Gundela

    2009-01-01

    The white matter (WM) of the adult human neocortex contains the so-called “interstitial neurons”. They are most numerous in the superficial WM underlying the cortical gyri, and decrease in density toward the deep WM. They are morphologically heterogeneous. A subgroup of interstitial neurons display pyramidal-cell like morphologies, characterized by a polarized dendritic tree with a dominant apical dendrite, and covered with a variable number of dendritic spines. In addition, a large contingent of interstitial neurons can be classified as interneurons based on their neurochemical profile as well as on morphological criteria. WM- interneurons have multipolar or bipolar shapes and express GABA and a variety of other neuronal markers, such as calbindin and calretinin, the extracellular matrix protein reelin, or neuropeptide Y, somatostatin, and nitric oxide synthase. The heterogeneity of interstitial neurons may be relevant for the pathogenesis of Alzheimer disease and schizophrenia. Interstitial neurons are most prominent in human brain, and only rudimentary in the brain of non-primate mammals. These evolutionary differences have precluded adequate experimental work on this cell population, which is usually considered as a relict of the subplate, a transient compartment proper of development and without a known function in the adult brain. The primate-specific prominence of the subplate in late fetal stages points to an important role in the establishment of interstitial neurons. Neurons in the adult WM may be actively involved in coordinating inter-areal connectivity and regulation of blood flow. Further studies in primates will be needed to elucidate the developmental history, adult components and activities of this large neuronal system. PMID:19543540

  6. Applicability of dose conversion coefficients of ICRP 74 to Asian adult males: Monte Carlo simulation study.

    PubMed

    Lee, Choonsik; Lee, Choonik; Lee, Jai-Ki

    2007-05-01

    International Commission on Radiological Protection (ICRP) reported comprehensive dose conversion coefficients for adult population, which is exposed to external photon sources in the Publication 74. However, those quantities were calculated from so-called stylized (or mathematical) phantoms composed of simplified mathematical surface equations so that the discrepancy between the phantoms and real human anatomy has been investigated by several authors using Caucasian-based voxel phantoms. To address anatomical and racial limitations of the stylized phantoms, several Asian-based voxel phantoms have been developed by Korean and Japanese investigators, independently. In the current study, photon dose conversion coefficients of ICRP 74 were compared with those from a total of five Asian-based male voxel phantoms, whose body dimensions were almost identical. Those of representative radio-sensitive organs (testes, red bone marrow, colon, lungs, and stomach), and effective dose conversion coefficients were obtained for comparison. Even though organ doses for testes, colon and lungs, and effective doses from ICRP 74 agreed well with those from Asian voxel phantoms within 10%, absorbed doses for red bone marrow and stomach showed significant discrepancies up to 30% which was mainly attributed to difference of phantom description between stylized and voxel phantoms. This study showed that the ICRP 74 dosimetry data, which have been reported to be unrealistic compared to those from Caucasian-based voxel phantoms, are also not appropriate for Asian population. PMID:17337194

  7. Breast phantom for mammary tissue characterization by near infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Miranda, D. A.; Cristiano, K. L.; Gutiérrez, J. C.

    2013-11-01

    Breast cancer is a disease associated to a high morbidity and mortality in the entire world. In the study of early detection of breast cancer the development of phantom is so important. In this research we fabricate a breast phantom using a ballistic gel with special modifications to simulate a normal and abnormal human breast. Optical properties of woman breast in the near infrared region were modelled with the phantom we developed. The developed phantom was evaluated with near infrared spectroscopy in order to study its relation with breast tissue. A good optical behaviour was achieved with the model fabricated.

  8. Image based Monte Carlo Modeling for Computational Phantom

    NASA Astrophysics Data System (ADS)

    Cheng, Mengyun; Wang, Wen; Zhao, Kai; Fan, Yanchang; Long, Pengcheng; Wu, Yican

    2014-06-01

    The evaluation on the effects of ionizing radiation and the risk of radiation exposure on human body has been becoming one of the most important issues for radiation protection and radiotherapy fields, which is helpful to avoid unnecessary radiation and decrease harm to human body. In order to accurately evaluate the dose on human body, it is necessary to construct more realistic computational phantom. However, manual description and verfication of the models for Monte carlo(MC)simulation are very tedious, error-prone and time-consuming. In addiation, it is difficult to locate and fix the geometry error, and difficult to describe material information and assign it to cells. MCAM (CAD/Image-based Automatic Modeling Program for Neutronics and Radiation Transport Simulation) was developed as an interface program to achieve both CAD- and image-based automatic modeling by FDS Team (Advanced Nuclear Energy Research Team, http://www.fds.org.cn). The advanced version (Version 6) of MCAM can achieve automatic conversion from CT/segmented sectioned images to computational phantoms such as MCNP models. Imaged-based automatic modeling program(MCAM6.0) has been tested by several medical images and sectioned images. And it has been applied in the construction of Rad-HUMAN. Following manual segmentation and 3D reconstruction, a whole-body computational phantom of Chinese adult female called Rad-HUMAN was created by using MCAM6.0 from sectioned images of a Chinese visible human dataset. Rad-HUMAN contains 46 organs/tissues, which faithfully represented the average anatomical characteristics of the Chinese female. The dose conversion coefficients(Dt/Ka) from kerma free-in-air to absorbed dose of Rad-HUMAN were calculated. Rad-HUMAN can be applied to predict and evaluate dose distributions in the Treatment Plan System (TPS), as well as radiation exposure for human body in radiation protection.

  9. Characterization of a phantom setup for breast conserving cancer surgery

    NASA Astrophysics Data System (ADS)

    Chadwell, Jacob T.; Conley, Rebekah H.; Collins, Jarrod A.; Meszoely, Ingrid M.; Miga, Michael I.

    2016-03-01

    The purpose of this work is to develop an anatomically and mechanically representative breast phantom for the validation of breast conserving surgical therapies, specifically, in this case, image guided surgeries. Using three patients scheduled for lumpectomy and four healthy volunteers in mock surgical presentations, the magnitude, direction, and location of breast deformations was analyzed. A phantom setup was then designed to approximate such deformations in a mock surgical environment. Specifically, commercially available and custom-built polyvinyl alcohol (PVA) phantoms were used to mimic breast tissue during surgery. A custom designed deformation apparatus was then created to reproduce deformations seen in typical clinical setups of the pre- and intra-operative breast geometry. Quantitative analysis of the human subjects yielded a positive correlation between breast volume and amount of breast deformation. Phantom results reflected similar behavior with the custom-built PVA phantom outperforming the commercial phantom.

  10. Influence of Manufacturing Processes on the Performance of Phantom Lungs

    SciTech Connect

    Traub, Richard J.

    2008-10-01

    Chest counting is an important tool for estimating the radiation dose to individuals who have inhaled radioactive materials. Chest counting systems are calibrated by counting the activity in the lungs of phantoms where the activity in the phantom lungs is known. In the United States a commonly used calibration phantom was developed at the Lawrence Livermore National Laboratory and is referred to as the Livermore Torso Phantom. An important feature of this phantom is that the phantom lungs can be interchanged so that the counting system can be challenged by different combinations of radionuclides and activity. Phantom lungs are made from lung tissue substitutes whose constituents are foaming plastics and various adjuvants selected to make the lung tissue substitute similar to normal healthy lung tissue. Some of the properties of phantom lungs cannot be readily controlled by phantom lung manufacturers. Some, such as density, are a complex function of the manufacturing process, while others, such as elemental composition of the bulk plastic are controlled by the plastics manufacturer without input, or knowledge of the phantom manufacturer. Despite the fact that some of these items cannot be controlled, they can be measured and accounted for. This report describes how manufacturing processes can influence the performance of phantom lungs. It is proposed that a metric that describes the brightness of the lung be employed by the phantom lung manufacturer to determine how well the phantom lung approximates the characteristics of a human lung. For many purposes, the linear attenuation of the lung tissue substitute is an appropriate surrogate for the brightness.

  11. Construction of boundary-surface-based Chinese female astronaut computational phantom and proton dose estimation

    PubMed Central

    Sun, Wenjuan; JIA, Xianghong; XIE, Tianwu; XU, Feng; LIU, Qian

    2013-01-01

    With the rapid development of China's space industry, the importance of radiation protection is increasingly prominent. To provide relevant dose data, we first developed the Visible Chinese Human adult Female (VCH-F) phantom, and performed further modifications to generate the VCH-F Astronaut (VCH-FA) phantom, incorporating statistical body characteristics data from the first batch of Chinese female astronauts as well as reference organ mass data from the International Commission on Radiological Protection (ICRP; both within 1% relative error). Based on cryosection images, the original phantom was constructed via Non-Uniform Rational B-Spline (NURBS) boundary surfaces to strengthen the deformability for fitting the body parameters of Chinese female astronauts. The VCH-FA phantom was voxelized at a resolution of 2 × 2 × 4 mm3for radioactive particle transport simulations from isotropic protons with energies of 5000–10 000 MeV in Monte Carlo N-Particle eXtended (MCNPX) code. To investigate discrepancies caused by anatomical variations and other factors, the obtained doses were compared with corresponding values from other phantoms and sex-averaged doses. Dose differences were observed among phantom calculation results, especially for effective dose with low-energy protons. Local skin thickness shifts the breast dose curve toward high energy, but has little impact on inner organs. Under a shielding layer, organ dose reduction is greater for skin than for other organs. The calculated skin dose per day closely approximates measurement data obtained in low-Earth orbit (LEO). PMID:23135158

  12. Fabrication of subcutaneous veins phantom for vessel visualization system

    NASA Astrophysics Data System (ADS)

    Cheng, Kai; Narita, Kazuyuki; Morita, Yusuke; Nakamachi, Eiji; Honda, Norihiro; Awazu, Kunio

    2013-09-01

    The technique of subcutaneous veins imaging by using NIR (Near Infrared Radiation) is widely used in medical applications, such as the intravenous injection and the blood sampling. In the previous study, an automatic 3D blood vessel search and automatic blood sampling system was newly developed. In order to validate this NIR imaging system, we adopted the subcutaneous vein in the human arm and its artificial phantom, which imitate the human fat and blood vessel. The human skin and subcutaneous vein is characterized as the uncertainty object, which has the individual specificity, non-accurate depth information, non-steady state and hardly to be fixed in the examination apparatus. On the other hand, the conventional phantom was quite distinct from the human's characteristics, such as the non-multilayer structure, disagreement of optical property. In this study, we develop a multilayer phantom, which is quite similar with human skin, for improvement of NIR detection system evaluation. The phantom consists of three layers, such as the epidermis layer, the dermis layer and the subcutaneous fat layer. In subcutaneous fat layer, we built a blood vessel. We use the intralipid to imitate the optical scattering characteristics of human skin, and the hemoglobin and melanin for the optical absorption characteristics. In this study, we did two subjects. First, we decide the fabrication process of the phantom. Second, we compared newly developed phantoms with human skin by using our NIR detecting system, and confirm the availability of these phantoms.

  13. Ontogeny of morningness-eveningness across the adult human lifespan

    NASA Astrophysics Data System (ADS)

    Randler, Christoph

    2016-02-01

    Sleep timing of humans can be classified alongside a continuum from early to late sleepers, with some people (larks) having an early activity, early bed, and rise times and others (owls) with a more nocturnally orientated activity. Only a few studies reported that morningness-eveningness changes significantly during the adult lifespan based on community samples. Here, I applied a different methodological approach to seek for evidence for the age-related changes in morningness-eveningness preferences by using a meta-data from all available studies. The new aspect of this cross-sectional approach is that only a few studies themselves address the age-related changes of the adult lifespan development, but that many studies are available that provide exactly the data needed. The studies came from 27 countries and included 36,939 participants. Age was highly significantly correlated with scores on the Composite Scale of Morningness ( r = 0.70). This relationship seems linear, because a linear regression explained nearly the same amount of variance compared to other models such as logarithmic, quadratic, or cubic models. The standard deviation of age correlated with the standard deviation of CSM scores ( r = 0.55), suggesting when there is much variance in age in a study; in turn, there is much variance in morningness. This meta-analytical approach shows that morningness-eveningness changes across the adult lifespan and that older age is related to higher morningness.

  14. The Phantom brane revisited

    NASA Astrophysics Data System (ADS)

    Sahni, Varun

    2016-07-01

    The Phantom brane is based on the normal branch of the DGP braneworld. It possesses a phantom-like equation of state at late times, but no big-rip future singularity. In this braneworld, the cosmological constant is dynamically screened at late times. Consequently it provides a good fit to SDSS DR11 measurements of H(z) at high redshifts. We obtain a closed system of equations for scalar perturbations on the brane. Perturbations of radiation, matter and the Weyl fluid are self-consistently evolved until the present epoch. We find that the late time growth of density perturbations on the brane proceeds at a faster rate than in ΛCDM. Additionally, the gravitational potentials φ, Ψ evolve differently on the brane than in ΛCDM, for which φ = Ψ. On the Brane, by contrast, the ratio φ/Ψ exceeds unity during the late matter dominated epoch (z ≤ 50). These features emerge as smoking gun tests of phantom brane cosmology and allow predictions of this scenario to be tested against observations of galaxy clustering and large scale structure. The phantom brane also displays a pole in its equation of state, which provides a key test of this dark energy model.

  15. Jamitons: Phantom Traffic Jams

    ERIC Educational Resources Information Center

    Kowszun, Jorj

    2013-01-01

    Traffic on motorways can slow down for no apparent reason. Sudden changes in speed by one or two drivers can create a chain reaction that causes a traffic jam for the vehicles that are following. This kind of phantom traffic jam is called a "jamiton" and the article discusses some of the ways in which traffic engineers produce…

  16. Automated Analysis of Mammography Phantom Images

    NASA Astrophysics Data System (ADS)

    Brooks, Kenneth Wesley

    The present work stems from the hypothesis that humans are inconsistent when making subjective analyses of images and that human decisions for moderately complex images may be performed by a computer with complete objectivity, once a human acceptance level has been established. The following goals were established to test the hypothesis: (1) investigate observer variability within the standard mammographic phantom evaluation process; (2) evaluate options for high-resolution image digitization and utilize the most appropriate technology for standard mammographic phantom film digitization; (3) develop a machine-based vision system for evaluating standard mammographic phantom images to eliminate effects of human variabilities; and (4) demonstrate the completed system's performance against human observers for accreditation and for manufacturing quality control of standard mammographic phantom images. The following methods and procedures were followed to achieve the goals of the research: (1) human variabilities in the American College of Radiology accreditation process were simulated by observer studies involving 30 medical physicists and these were compared to the same number of diagnostic radiologists and untrained control group of observers; (2) current digitization technologies were presented and performance test procedures were developed; three devices were tested which represented commercially available high, intermediate and low-end contrast and spatial resolution capabilities; (3) optimal image processing schemes were applied and tested which performed low, intermediate and high-level computer vision tasks; and (4) the completed system's performance was tested against human observers for accreditation and for manufacturing quality control of standard mammographic phantom images. The results from application of the procedures were as follows: (1) the simulated American College of Radiology mammography accreditation program phantom evaluation process demonstrated

  17. Multipotent progenitor cells isolated from adult human pancreatic tissue.

    PubMed

    Todorov, I; Nair, I; Ferreri, K; Rawson, J; Kuroda, A; Pascual, M; Omori, K; Valiente, L; Orr, C; Al-Abdullah, I; Riggs, A; Kandeel, F; Mullen, Y

    2005-10-01

    The supply of islet cells is a limiting factor for the widespread application of islet transplantation of type-1 diabetes. Islets constitute 1% to 2% of pancreatic tissue, leaving approximately 98% as discard after islet isolation and purification. In this report we present our data on the isolation of multipotent progenitor cells from discarded adult human pancreatic tissue. The collected cells from discarded nonislet fractions, after enzymatic digestion and gradient purification of islets, were dissociated for suspension culture in a serum-free medium. The cell clusters grown to a size of 100 to 150 mum contained cells staining for stage-specific embryonic antigens, but not insulin or C-peptide. To direct cell differentiation toward islets, clusters were recultured in a pancreatic differentiation medium. Insulin and C-peptide-positive cells by immunocytochemistry appeared within a week, reaching over 10% of the cell population. Glucagon and somatostatin-positive cells were also detected. The cell clusters were found to secrete insulin in response to glucose stimulation. Cells from the same clusters also had the capacity for differentiation into neural cells, as documented by staining for neural and glial cell markers when cultured as monolayers in media containing neurotrophic factors. These data suggest that multipotent pancreatic progenitor cells exist within the human pancreatic tissue that is typically discarded during islet isolation procedures. These adult progenitor cells can be successfully differentiated into insulin-producing cells, and thus they have the potential for treatment of type-1 diabetes mellitus. PMID:16298614

  18. Egg White Phantoms for HIFU

    SciTech Connect

    Divkovic, Gabriela; Jenne, Juergen W.

    2005-03-28

    We used fresh egg white and polyacrylamide to create a transparent tissue mimicking phantom. Heating of phantoms by HIFU leads to egg white protein denaturation and creation of visible white lesions. We measured the acoustical and thermal properties and investigated the possibility to use such phantoms to study the lesion formation during the HIFU therapy.

  19. New eye phantom for ophthalmic surgery

    NASA Astrophysics Data System (ADS)

    Fogli, Gessica; Orsi, Gianni; De Maria, Carmelo; Montemurro, Francesca; Palla, Michele; Rizzo, Stanislao; Vozzi, Giovanni

    2014-06-01

    In this work, we designed and realized a new phantom able to mimic the principal mechanical, rheological, and physical cues of the human eye and that can be used as a common benchmark to validate new surgical procedures, innovative vitrectomes, and as a training system for surgeons. This phantom, in particular its synthetic humor vitreous, had the aim of reproducing diffusion properties of the natural eye and can be used as a system to evaluate the pharmacokinetics of drugs and optimization of their dose, limiting animal experiments. The eye phantom was built layer-by-layer starting from the sclera up to the retina, using low cost and easy to process polymers. The validation of the phantom was carried out by mechanical characterization of each layer, by diffusion test with commercial drugs into a purposely developed apparatus, and finally by a team of ophthalmic surgeons. Experiments demonstrated that polycaprolactone, polydimethylsiloxane, and gelatin, properly prepared, are the best materials to mimic the mechanical properties of sclera, choroid, and retina, respectively. A polyvinyl alcohol-gelatin polymeric system is the best for mimicking the viscosity of the human humor vitreous, even if the bevacizumab half-life is lower than in the human eye.

  20. New eye phantom for ophthalmic surgery.

    PubMed

    Fogli, Gessica; Orsi, Gianni; De Maria, Carmelo; Montemurro, Francesca; Palla, Michele; Rizzo, Stanislao; Vozzi, Giovanni

    2014-06-01

    In this work, we designed and realized a new phantom able to mimic the principal mechanical, rheological, and physical cues of the human eye and that can be used as a common benchmark to validate new surgical procedures, innovative vitrectomes, and as a training system for surgeons. This phantom, in particular its synthetic humor vitreous, had the aim of reproducing diffusion properties of the natural eye and can be used as a system to evaluate the pharmacokinetics of drugs and optimization of their dose, limiting animal experiments. The eye phantom was built layer-by-layer starting from the sclera up to the retina, using low cost and easy to process polymers. The validation of the phantom was carried out by mechanical characterization of each layer, by diffusion test with commercial drugs into a purposely developed apparatus, and finally by a team of ophthalmic surgeons. Experiments demonstrated that polycaprolactone, polydimethylsiloxane, and gelatin, properly prepared, are the best materials to mimic the mechanical properties of sclera, choroid, and retina, respectively. A polyvinyl alcohol-gelatin polymeric system is the best for mimicking the viscosity of the human humor vitreous, even if the bevacizumab half-life is lower than in the human eye. PMID:24887746

  1. A Rat Body Phantom for Radiation Analysis

    NASA Technical Reports Server (NTRS)

    Qualls, Garry D.; Clowdsley, Martha S.; Slaba, Tony C.; Walker, Steven A.

    2010-01-01

    To reduce the uncertainties associated with estimating the biological effects of ionizing radiation in tissue, researchers rely on laboratory experiments in which mono-energetic, single specie beams are applied to cell cultures, insects, and small animals. To estimate the radiation effects on astronauts in deep space or low Earth orbit, who are exposed to mixed field broad spectrum radiation, these experimental results are extrapolated and combined with other data to produce radiation quality factors, radiation weighting factors, and other risk related quantities for humans. One way to reduce the uncertainty associated with such extrapolations is to utilize analysis tools that are applicable to both laboratory and space environments. The use of physical and computational body phantoms to predict radiation exposure and its effects is well established and a wide range of human and non-human phantoms are in use today. In this paper, a computational rat phantom is presented, as well as a description of the process through which that phantom has been coupled to existing radiation analysis tools. Sample results are presented for two space radiation environments.

  2. Solid anthropomorphic infant whole body DXA phantom: Design, evaluation, and multisite testing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dual energy X-ray absorptiometry (DXA) requires phantoms for quality control and cross-calibration. No commercially available phantoms are designed specifically for infant whole-body scanning. We fabricated a phantom closely matching a 7-kg human infant in body habitus using PVC, nylon-mix, and poly...

  3. Neuropeptide Y in the adult and fetal human pineal gland.

    PubMed

    Møller, Morten; Phansuwan-Pujito, Pansiri; Badiu, Corin

    2014-01-01

    Neuropeptide Y was isolated from the porcine brain in 1982 and shown to be colocalized with noradrenaline in sympathetic nerve terminals. The peptide has been demonstrated to be present in sympathetic nerve fibers innervating the pineal gland in many mammalian species. In this investigation, we show by use of immunohistochemistry that neuropeptide Y is present in nerve fibers of the adult human pineal gland. The fibers are classical neuropeptidergic fibers endowed with large boutons en passage and primarily located in a perifollicular position with some fibers entering the pineal parenchyma inside the follicle. The distance from the immunoreactive terminals to the pinealocytes indicates a modulatory function of neuropeptide Y for pineal physiology. Some of the immunoreactive fibers might originate from neurons located in the brain and be a part of the central innervation of the pineal gland. In a series of human fetuses, neuropeptide Y-containing nerve fibers was present and could be detected as early as in the pineal of four- to five-month-old fetuses. This early innervation of the human pineal is different from most rodents, where the innervation starts postnatally.

  4. Regular phantom black holes.

    PubMed

    Bronnikov, K A; Fabris, J C

    2006-06-30

    We study self-gravitating, static, spherically symmetric phantom scalar fields with arbitrary potentials (favored by cosmological observations) and single out 16 classes of possible regular configurations with flat, de Sitter, and anti-de Sitter asymptotics. Among them are traversable wormholes, bouncing Kantowski-Sachs (KS) cosmologies, and asymptotically flat black holes (BHs). A regular BH has a Schwarzschild-like causal structure, but the singularity is replaced by a de Sitter infinity, giving a hypothetic BH explorer a chance to survive. It also looks possible that our Universe has originated in a phantom-dominated collapse in another universe, with KS expansion and isotropization after crossing the horizon. Explicit examples of regular solutions are built and discussed. Possible generalizations include k-essence type scalar fields (with a potential) and scalar-tensor gravity.

  5. Tissue-like phantoms

    DOEpatents

    Frangioni, John V.; De Grand, Alec M.

    2007-10-30

    The invention is based, in part, on the discovery that by combining certain components one can generate a tissue-like phantom that mimics any desired tissue, is simple and inexpensive to prepare, and is stable over many weeks or months. In addition, new multi-modal imaging objects (e.g., beads) can be inserted into the phantoms to mimic tissue pathologies, such as cancer, or merely to serve as calibration standards. These objects can be imaged using one, two, or more (e.g., four) different imaging modalities (e.g., x-ray computed tomography (CT), positron emission tomography (PET), single photon emission computed tomography (SPECT), and near-infrared (NIR) fluorescence) simultaneously.

  6. Gustatory reaction time to various sweeteners in human adults.

    PubMed

    Yamamoto, T; Kato, T; Matsuo, R; Kawamura, Y; Yoshida, M

    1985-09-01

    Reaction times to recognize the sweet taste of 12 sweeteners at various concentrations were measured in 48 human adults. The reaction time (T) decreased with increasing concentration (C) of each sweetener applied to the anterior dorsal tongue. The relationships between T and C, and T and logC were well described by a rectangular hyperbola formula for each of the 12 sweeteners. Reaction times to discriminate sweet taste quality between pairs of sweeteners were measured, then a similarity index was calculated. Factor analysis based on correlation coefficients between pairs of sweeteners which were obtained by the similarity indices has indicated classification of the sweeteners. Sucrose, fructose, glucose, maltose, sorbitol and aspartame tend to group together. Na-cyclamate and Na-saccharin form another group. DL-alanine, stevioside and neohesperidin dihydrochalcone are rather independent and do not belong to any group.

  7. Kerr-like phantom wormhole

    NASA Astrophysics Data System (ADS)

    Miranda, Galaxia; Matos, Tonatiuh; García, Nadiezhda Montelongo

    2014-01-01

    In this work we study a Kerr-like wormhole with an scalar field with opposite sign as source (Phantom). It has three parameters: mass, angular momentum and scalar field charge. This space-time has a naked ring singularity, otherwise it is regular everywhere. The main feature of this wormhole is that the mouth of the throat lies on a sphere of the same radius as the ring singularity and apparently does not allow any observer to reach the singularity, it behaves like an anti-horizon. After analyzing the geodesics of the wormhole we find that an observer can go through the wormhole without troubles, but the equator presents an infinite potential barrier which does not allow any geodesic from reaching the throat. From an analysis of the Riemann tensor we obtain that the tidal forces are small and could allow the wormhole to be traversable, from the north pole, for an observer like a human being.

  8. A biokinetic model for systemic technetium in adult humans

    DOE PAGES

    Leggett, Richard Wayne; Giussani, Augusto

    2015-04-10

    The International Commission on Radiological Protection (ICRP) currently is updating its biokinetic and dosimetric models for internally deposited radionuclides. Technetium (Tc), the lightest element that exists only in radioactive form, has two important isotopes from the standpoint of potential risk to humans: the long-lived isotope 99Tm(T1/2=2.1x105 y) is present in high concentration in nuclear waste, and the short-lived isotope 99mTc (T1/2=6.02 h) is the most commonly used radionuclide in diagnostic nuclear medicine. This paper reviews data on the biological behavior of technetium and proposes a biokinetic model for systemic technetium in the adult human body for use in radiation protection.more » Compared with the ICRP s current occupational model for systemic technetium, the proposed model provides a more realistic description of the paths of movement of technetium in the body; provides greater consistency with experimental and medical data; and, for most radiosensitive organs, yields substantially different estimates of cumulative activity (total radioactive decays within the organ) following uptake of 99Tm or 99mTc to blood.« less

  9. Comprehensive cellular‐resolution atlas of the adult human brain

    PubMed Central

    Royall, Joshua J.; Sunkin, Susan M.; Ng, Lydia; Facer, Benjamin A.C.; Lesnar, Phil; Guillozet‐Bongaarts, Angie; McMurray, Bergen; Szafer, Aaron; Dolbeare, Tim A.; Stevens, Allison; Tirrell, Lee; Benner, Thomas; Caldejon, Shiella; Dalley, Rachel A.; Dee, Nick; Lau, Christopher; Nyhus, Julie; Reding, Melissa; Riley, Zackery L.; Sandman, David; Shen, Elaine; van der Kouwe, Andre; Varjabedian, Ani; Write, Michelle; Zollei, Lilla; Dang, Chinh; Knowles, James A.; Koch, Christof; Phillips, John W.; Sestan, Nenad; Wohnoutka, Paul; Zielke, H. Ronald; Hohmann, John G.; Jones, Allan R.; Bernard, Amy; Hawrylycz, Michael J.; Hof, Patrick R.; Fischl, Bruce

    2016-01-01

    ABSTRACT Detailed anatomical understanding of the human brain is essential for unraveling its functional architecture, yet current reference atlases have major limitations such as lack of whole‐brain coverage, relatively low image resolution, and sparse structural annotation. We present the first digital human brain atlas to incorporate neuroimaging, high‐resolution histology, and chemoarchitecture across a complete adult female brain, consisting of magnetic resonance imaging (MRI), diffusion‐weighted imaging (DWI), and 1,356 large‐format cellular resolution (1 µm/pixel) Nissl and immunohistochemistry anatomical plates. The atlas is comprehensively annotated for 862 structures, including 117 white matter tracts and several novel cyto‐ and chemoarchitecturally defined structures, and these annotations were transferred onto the matching MRI dataset. Neocortical delineations were done for sulci, gyri, and modified Brodmann areas to link macroscopic anatomical and microscopic cytoarchitectural parcellations. Correlated neuroimaging and histological structural delineation allowed fine feature identification in MRI data and subsequent structural identification in MRI data from other brains. This interactive online digital atlas is integrated with existing Allen Institute for Brain Science gene expression atlases and is publicly accessible as a resource for the neuroscience community. J. Comp. Neurol. 524:3127–3481, 2016. © 2016 The Authors The Journal of Comparative Neurology Published by Wiley Periodicals, Inc. PMID:27418273

  10. Comprehensive cellular-resolution atlas of the adult human brain.

    PubMed

    Ding, Song-Lin; Royall, Joshua J; Sunkin, Susan M; Ng, Lydia; Facer, Benjamin A C; Lesnar, Phil; Guillozet-Bongaarts, Angie; McMurray, Bergen; Szafer, Aaron; Dolbeare, Tim A; Stevens, Allison; Tirrell, Lee; Benner, Thomas; Caldejon, Shiella; Dalley, Rachel A; Dee, Nick; Lau, Christopher; Nyhus, Julie; Reding, Melissa; Riley, Zackery L; Sandman, David; Shen, Elaine; van der Kouwe, Andre; Varjabedian, Ani; Write, Michelle; Zollei, Lilla; Dang, Chinh; Knowles, James A; Koch, Christof; Phillips, John W; Sestan, Nenad; Wohnoutka, Paul; Zielke, H Ronald; Hohmann, John G; Jones, Allan R; Bernard, Amy; Hawrylycz, Michael J; Hof, Patrick R; Fischl, Bruce; Lein, Ed S

    2016-11-01

    Detailed anatomical understanding of the human brain is essential for unraveling its functional architecture, yet current reference atlases have major limitations such as lack of whole-brain coverage, relatively low image resolution, and sparse structural annotation. We present the first digital human brain atlas to incorporate neuroimaging, high-resolution histology, and chemoarchitecture across a complete adult female brain, consisting of magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI), and 1,356 large-format cellular resolution (1 µm/pixel) Nissl and immunohistochemistry anatomical plates. The atlas is comprehensively annotated for 862 structures, including 117 white matter tracts and several novel cyto- and chemoarchitecturally defined structures, and these annotations were transferred onto the matching MRI dataset. Neocortical delineations were done for sulci, gyri, and modified Brodmann areas to link macroscopic anatomical and microscopic cytoarchitectural parcellations. Correlated neuroimaging and histological structural delineation allowed fine feature identification in MRI data and subsequent structural identification in MRI data from other brains. This interactive online digital atlas is integrated with existing Allen Institute for Brain Science gene expression atlases and is publicly accessible as a resource for the neuroscience community. J. Comp. Neurol. 524:3127-3481, 2016. © 2016 The Authors The Journal of Comparative Neurology Published by Wiley Periodicals, Inc. PMID:27418273

  11. Comprehensive cellular-resolution atlas of the adult human brain.

    PubMed

    Ding, Song-Lin; Royall, Joshua J; Sunkin, Susan M; Ng, Lydia; Facer, Benjamin A C; Lesnar, Phil; Guillozet-Bongaarts, Angie; McMurray, Bergen; Szafer, Aaron; Dolbeare, Tim A; Stevens, Allison; Tirrell, Lee; Benner, Thomas; Caldejon, Shiella; Dalley, Rachel A; Dee, Nick; Lau, Christopher; Nyhus, Julie; Reding, Melissa; Riley, Zackery L; Sandman, David; Shen, Elaine; van der Kouwe, Andre; Varjabedian, Ani; Write, Michelle; Zollei, Lilla; Dang, Chinh; Knowles, James A; Koch, Christof; Phillips, John W; Sestan, Nenad; Wohnoutka, Paul; Zielke, H Ronald; Hohmann, John G; Jones, Allan R; Bernard, Amy; Hawrylycz, Michael J; Hof, Patrick R; Fischl, Bruce; Lein, Ed S

    2016-11-01

    Detailed anatomical understanding of the human brain is essential for unraveling its functional architecture, yet current reference atlases have major limitations such as lack of whole-brain coverage, relatively low image resolution, and sparse structural annotation. We present the first digital human brain atlas to incorporate neuroimaging, high-resolution histology, and chemoarchitecture across a complete adult female brain, consisting of magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI), and 1,356 large-format cellular resolution (1 µm/pixel) Nissl and immunohistochemistry anatomical plates. The atlas is comprehensively annotated for 862 structures, including 117 white matter tracts and several novel cyto- and chemoarchitecturally defined structures, and these annotations were transferred onto the matching MRI dataset. Neocortical delineations were done for sulci, gyri, and modified Brodmann areas to link macroscopic anatomical and microscopic cytoarchitectural parcellations. Correlated neuroimaging and histological structural delineation allowed fine feature identification in MRI data and subsequent structural identification in MRI data from other brains. This interactive online digital atlas is integrated with existing Allen Institute for Brain Science gene expression atlases and is publicly accessible as a resource for the neuroscience community. J. Comp. Neurol. 524:3127-3481, 2016. © 2016 The Authors The Journal of Comparative Neurology Published by Wiley Periodicals, Inc.

  12. A biokinetic model for systemic technetium in adult humans

    SciTech Connect

    Leggett, Richard Wayne; Giussani, Augusto

    2015-04-10

    The International Commission on Radiological Protection (ICRP) currently is updating its biokinetic and dosimetric models for internally deposited radionuclides. Technetium (Tc), the lightest element that exists only in radioactive form, has two important isotopes from the standpoint of potential risk to humans: the long-lived isotope 99Tm(T1/2=2.1x105 y) is present in high concentration in nuclear waste, and the short-lived isotope 99mTc (T1/2=6.02 h) is the most commonly used radionuclide in diagnostic nuclear medicine. This paper reviews data on the biological behavior of technetium and proposes a biokinetic model for systemic technetium in the adult human body for use in radiation protection. Compared with the ICRP s current occupational model for systemic technetium, the proposed model provides a more realistic description of the paths of movement of technetium in the body; provides greater consistency with experimental and medical data; and, for most radiosensitive organs, yields substantially different estimates of cumulative activity (total radioactive decays within the organ) following uptake of 99Tm or 99mTc to blood.

  13. The Adult Learner. The Definitive Classic in Adult Education and Human Resource Development. Fifth Edition.

    ERIC Educational Resources Information Center

    Knowles, Malcolm S.; Holton, Elwood F., III; Swanson, Richard A.

    This book examines the core principles of adult learning and the roots of andragogy, advances in adult learning, and practice in adult learning. The following are among the topics discussed in the book's 17 chapters: importance of learning theory; theories of learning (concept of part and whole models of development, theories based on elemental…

  14. Multi-Modality Phantom Development

    SciTech Connect

    Huber, Jennifer S.; Peng, Qiyu; Moses, William W.

    2009-03-20

    Multi-modality imaging has an increasing role in the diagnosis and treatment of a large number of diseases, particularly if both functional and anatomical information are acquired and accurately co-registered. Hence, there is a resulting need for multi modality phantoms in order to validate image co-registration and calibrate the imaging systems. We present our PET-ultrasound phantom development, including PET and ultrasound images of a simple prostate phantom. We use agar and gelatin mixed with a radioactive solution. We also present our development of custom multi-modality phantoms that are compatible with PET, transrectal ultrasound (TRUS), MRI and CT imaging. We describe both our selection of tissue mimicking materials and phantom construction procedures. These custom PET-TRUS-CT-MRI prostate phantoms use agargelatin radioactive mixtures with additional contrast agents and preservatives. We show multi-modality images of these custom prostate phantoms, as well as discuss phantom construction alternatives. Although we are currently focused on prostate imaging, this phantom development is applicable to many multi-modality imaging applications.

  15. Adult somatic stem cells in the human parasite, Schistosoma mansoni

    PubMed Central

    Collins, James J.; Wang, Bo; Lambrus, Bramwell G.; Tharp, Marla; Iyer, Harini; Newmark, Phillip A.

    2013-01-01

    Summary Schistosomiasis is among the most prevalent human parasitic diseases, affecting more than 200 million people worldwide1. The etiological agents of this disease are trematode flatworms (Schistosoma) that live and lay eggs within the vasculature of the host. These eggs lodge in host tissues, causing inflammatory responses that are the primary cause of morbidity. Because these parasites can live and reproduce within human hosts for decades2, elucidating the mechanisms that promote their longevity is of fundamental importance. Although adult pluripotent stem cells, called neoblasts, drive long-term homeostatic tissue maintenance in long-lived free-living flatworms3,4 (e.g., planarians), and neoblast-like cells have been described in some parasitic tapeworms5, little is known about whether similar cell types exist in any trematode species. Here, we describe a population of neoblast-like cells in the trematode Schistosoma mansoni. These cells resemble planarian neoblasts morphologically and share their ability to proliferate and differentiate into derivatives of multiple germ layers. Capitalizing on available genomic resources6,7 and RNAseq-based gene expression profiling, we find that these schistosome neoblast-like cells express a fibroblast growth factor receptor ortholog. Using RNA interference we demonstrate that this gene is required for the maintenance of these neoblast-like cells. Our observations suggest that adaptation of developmental strategies shared by free-living ancestors to modern-day schistosomes likely contributed to the success of these animals as long-lived obligate parasites. We expect that future studies deciphering the function of these neoblast-like cells will have important implications for understanding the biology of these devastating parasites. PMID:23426263

  16. An anatomically realistic temperature phantom for radiofrequency heating measurements

    PubMed Central

    Graedel, Nadine N.; Polimeni, Jonathan R.; Guerin, Bastien; Gagoski, Borjan; Wald, Lawrence L.

    2014-01-01

    Purpose An anthropomorphic phantom with realistic electrical properties allows for a more accurate reproduction of tissue current patterns during excitation. A temperature map can then probe the worst-case heating expected in the un-perfused case. We describe an anatomically realistic human head phantom that allows rapid 3D temperature mapping at 7 T. Methods The phantom was based on hand-labeled anatomical imaging data and consists of four compartments matching the corresponding human tissues in geometry and electrical properties. The increases in temperature resulting from radiofrequency excitation were measured with MR thermometry using a temperature sensitive contrast agent (TmDOTMA−) validated by direct fiber optic temperature measurements. Results Acquisition of 3D temperature maps of the full phantom with a temperature accuracy better than 0.1°C was achieved with an isotropic resolution of 5 mm and acquisition times of 2–4 minutes. Conclusion Our results demonstrate the feasibility of constructing anatomically realistic phantoms with complex geometries incorporating the ability to measure accurate temperature maps in the phantom. The anthropomorphic temperature phantom is expected to provide a useful tool for the evaluation of the heating effects of both conventional and parallel transmit pulses and help validate electromagnetic and temperature simulations. PMID:24549755

  17. A biokinetic model for systemic technetium in adult humans.

    PubMed

    Leggett, R; Giussani, A

    2015-06-01

    This paper reviews biokinetic data for technetium and proposes a biokinetic model for systemic technetium in adult humans. The development of parameter values focuses on data for pertechnetate TcO(-)(4) the most commonly encountered form of technetium and the form expected to be present in body fluids. The model is intended as a default model for occupational or environmental intake of technetium, i.e. applicable in the absence of form- or site-specific information. Tissues depicted explicitly in the model include thyroid, salivary glands, stomach wall, right colon wall, liver, kidneys, and bone. Compared with the ICRP's current biokinetic model for occupational or environmental intake of technetium (ICRP 1993, 1994), the proposed model provides a more detailed and biologically realistic description of the systemic behaviour of technetium and is based on a broader set of experimental and medical data. For acute input of (99m)Tc (T(1/2) = 6.02 h) to blood, the ratios of cumulative (time-integrated) activity predicted by the current ICRP model to that predicted by the proposed model range from 0.4-7 for systemic regions addressed explicitly in both models. For acute input of (99)Tc (T(1/2) = 2.1 × 10(5) year) to blood, the corresponding ratios range from 0.2-30.

  18. Metric analysis of basal sphenoid angle in adult human skulls

    PubMed Central

    Netto, Dante Simionato; Nascimento, Sergio Ricardo Rios; Ruiz, Cristiane Regina

    2014-01-01

    Objective To analyze the variations in the angle basal sphenoid skulls of adult humans and their relationship to sex, age, ethnicity and cranial index. Methods The angles were measured in 160 skulls belonging to the Museum of the Universidade Federal de São Paulo Department of Morphology. We use two flexible rules and a goniometer, having as reference points for the first rule the posterior end of the ethmoidal crest and dorsum of the sella turcica, and for the second rule the anterior margin of the foramen magnum and clivus, measuring the angle at the intersection of two. Results The average angle was 115.41°, with no statistical correlation between the value of the angle and sex or age. A statistical correlation was noted between the value of the angle and ethnicity, and between the angle and the horizontal cranial index. Conclusions The distribution of the angle basal sphenoid was the same in sex, and there was correlation between the angle and ethnicity, being the proportion of non-white individuals with an angle >125° significantly higher than that of whites with an angle >125°. There was correlation between the angle and the cranial index, because skulls with higher cranial index tend to have higher basiesfenoidal angle too. PMID:25295452

  19. Bone-forming capacity of adult human nasal chondrocytes

    PubMed Central

    Pippenger, Benjamin E; Ventura, Manuela; Pelttari, Karoliina; Feliciano, Sandra; Jaquiery, Claude; Scherberich, Arnaud; Walboomers, X Frank; Barbero, Andrea; Martin, Ivan

    2015-01-01

    Nasal chondrocytes (NC) derive from the same multipotent embryological segment that gives rise to the majority of the maxillofacial bone and have been reported to differentiate into osteoblast-like cells in vitro. In this study, we assessed the capacity of adult human NC, appropriately primed towards hypertrophic or osteoblastic differentiation, to form bone tissue in vivo. Hypertrophic induction of NC-based micromass pellets formed mineralized cartilaginous tissues rich in type X collagen, but upon implantation into subcutaneous pockets of nude mice remained avascular and reverted to stable hyaline-cartilage. In the same ectopic environment, NC embedded into ceramic scaffolds and primed with osteogenic medium only sporadically formed intramembranous bone tissue. A clonal study could not demonstrate that the low bone formation efficiency was related to a possibly small proportion of cells competent to become fully functional osteoblasts. We next tested whether the cues present in an orthotopic environment could induce a more efficient direct osteoblastic transformation of NC. Using a nude rat calvarial defect model, we demonstrated that (i) NC directly participated in frank bone formation and (ii) the efficiency of survival and bone formation by NC was significantly higher than that of reference osteogenic cells, namely bone marrow-derived mesenchymal stromal cells. This study provides a proof-of-principle that NC have the plasticity to convert into bone cells and thereby represent an easily available cell source to be further investigated for craniofacial bone regeneration. PMID:25689393

  20. Color-matched esophagus phantom for fluorescent imaging

    NASA Astrophysics Data System (ADS)

    Yang, Chenying; Hou, Vivian; Nelson, Leonard Y.; Seibel, Eric J.

    2013-02-01

    We developed a stable, reproducible three-dimensional optical phantom for the evaluation of a wide-field endoscopic molecular imaging system. This phantom mimicked a human esophagus structure with flexibility to demonstrate body movements. At the same time, realistic visual appearance and diffuse spectral reflectance properties of the tissue were simulated by a color matching methodology. A photostable dye-in-polymer technology was applied to represent biomarker probed "hot-spot" locations. Furthermore, fluorescent target quantification of the phantom was demonstrated using a 1.2mm ultrathin scanning fiber endoscope with concurrent fluorescence-reflectance imaging.

  1. NOTE: Simultaneous assessment of arsenic and selenium in human nail phantoms using a portable x-ray tube and a detector

    NASA Astrophysics Data System (ADS)

    Roy, Christopher W.; Gherase, Mihai Raul; Fleming, David E. B.

    2010-03-01

    A novel approach to the measurement of arsenic and selenium in nail phantoms is demonstrated. Two-component nail phantoms of 0.7 mm and 1.5 mm thickness were made from a polyester resin-salt mixture and dosed with equal arsenic and selenium concentrations ranging from 0 to 30 µg g-1. A backing was made to simulate the soft tissue and bone of the great toe. Characteristic x-rays for arsenic and selenium were recorded using a portable x-ray tube and a silicon PiN diode detector. The minimum instrumental detection limits for arsenic and selenium in 0.7 mm solitary nail samples were as follows: 0.510 ± 0.018 µg g-1 and 0.519 ± 0.026 µg g-1 respectively; for 1.5 mm solitary nail: 0.465 ± 0.035 µg g-1 and 0.561 ± 0.062 µg g-1 for 0.7 mm nail with backing: 1.522 ± 0.038 µg g-1 and 1.401 ± 0.049 µg g-1 for 1.5 mm nail with backing: 1.354 ± 0.054 µg g-1 and 1.367 ± 0.068 µg g-1.

  2. Bioassay Phantoms Using Medical Images and Computer Aided Manufacturing

    SciTech Connect

    Dr. X. Geroge Xu

    2011-01-28

    A radiation bioassay program relies on a set of standard human phantoms to calibrate and assess radioactivity levels inside a human body for radiation protection and nuclear medicine imaging purposes. However, the methodologies in the development and application of anthropomorphic phantoms, both physical and computational, had mostly remained the same for the past 40 years. We herein propose a 3-year research project to develop medical image-based physical and computational phantoms specifically for radiation bioassay applications involving internally deposited radionuclides. The broad, long-term objective of this research was to set the foundation for a systematic paradigm shift away from the anatomically crude phantoms in existence today to realistic and ultimately individual-specific bioassay methodologies. This long-term objective is expected to impact all areas of radiation bioassay involving nuclear power plants, U.S. DOE laboratories, and nuclear medicine clinics.

  3. Ultrasonic Calibration Wire Test Phantom

    SciTech Connect

    Lehman, S K; Fisher, K A; Werve, M; Chambers, D H

    2004-09-24

    We designed and built a phantom consisting of vertical wires maintained under tension to be used as an ultrasonic test, calibration, and reconstruction object for the Lawrence Livermore National Laboratory annular array scanner. We provide a description of the phantom, present example data sets, preliminary reconstructions, example metadata, and MATLAB codes to read the data.

  4. 4D XCAT phantom for multimodality imaging research

    SciTech Connect

    Segars, W. P.; Sturgeon, G.; Mendonca, S.; Grimes, Jason; Tsui, B. M. W.

    2010-09-15

    Purpose: The authors develop the 4D extended cardiac-torso (XCAT) phantom for multimodality imaging research. Methods: Highly detailed whole-body anatomies for the adult male and female were defined in the XCAT using nonuniform rational B-spline (NURBS) and subdivision surfaces based on segmentation of the Visible Male and Female anatomical datasets from the National Library of Medicine as well as patient datasets. Using the flexibility of these surfaces, the Visible Human anatomies were transformed to match body measurements and organ volumes for a 50th percentile (height and weight) male and female. The desired body measurements for the models were obtained using the PEOPLESIZE program that contains anthropometric dimensions categorized from 1st to the 99th percentile for US adults. The desired organ volumes were determined from ICRP Publication 89 [ICRP, ''Basic anatomical and physiological data for use in radiological protection: reference values,'' ICRP Publication 89 (International Commission on Radiological Protection, New York, NY, 2002)]. The male and female anatomies serve as standard templates upon which anatomical variations may be modeled in the XCAT through user-defined parameters. Parametrized models for the cardiac and respiratory motions were also incorporated into the XCAT based on high-resolution cardiac- and respiratory-gated multislice CT data. To demonstrate the usefulness of the phantom, the authors show example simulation studies in PET, SPECT, and CT using publicly available simulation packages. Results: As demonstrated in the pilot studies, the 4D XCAT (which includes thousands of anatomical structures) can produce realistic imaging data when combined with accurate models of the imaging process. With the flexibility of the NURBS surface primitives, any number of different anatomies, cardiac or respiratory motions or patterns, and spatial resolutions can be simulated to perform imaging research. Conclusions: With the ability to produce

  5. 4D XCAT phantom for multimodality imaging research

    PubMed Central

    Segars, W. P.; Sturgeon, G.; Mendonca, S.; Grimes, Jason; Tsui, B. M. W.

    2010-01-01

    Purpose: The authors develop the 4D extended cardiac-torso (XCAT) phantom for multimodality imaging research. Methods: Highly detailed whole-body anatomies for the adult male and female were defined in the XCAT using nonuniform rational B-spline (NURBS) and subdivision surfaces based on segmentation of the Visible Male and Female anatomical datasets from the National Library of Medicine as well as patient datasets. Using the flexibility of these surfaces, the Visible Human anatomies were transformed to match body measurements and organ volumes for a 50th percentile (height and weight) male and female. The desired body measurements for the models were obtained using the PEOPLESIZE program that contains anthropometric dimensions categorized from 1st to the 99th percentile for US adults. The desired organ volumes were determined from ICRP Publication 89 [ICRP, ‘‘Basic anatomical and physiological data for use in radiological protection: reference values,” ICRP Publication 89 (International Commission on Radiological Protection, New York, NY, 2002)]. The male and female anatomies serve as standard templates upon which anatomical variations may be modeled in the XCAT through user-defined parameters. Parametrized models for the cardiac and respiratory motions were also incorporated into the XCAT based on high-resolution cardiac- and respiratory-gated multislice CT data. To demonstrate the usefulness of the phantom, the authors show example simulation studies in PET, SPECT, and CT using publicly available simulation packages. Results: As demonstrated in the pilot studies, the 4D XCAT (which includes thousands of anatomical structures) can produce realistic imaging data when combined with accurate models of the imaging process. With the flexibility of the NURBS surface primitives, any number of different anatomies, cardiac or respiratory motions or patterns, and spatial resolutions can be simulated to perform imaging research. Conclusions: With the ability to produce

  6. Phantom Limb Sensation (PLS) and Phantom Limb Pain (PLP) among Young Landmine Amputees

    PubMed Central

    POOR ZAMANY NEJATKERMANY, Mahtab; MODIRIAN, Ehsan; SOROUSH, Mohammadreza; MASOUMI, Mehdi; HOSSEINI, Maryam

    2016-01-01

    Objective To determine the frequency of phantom limb sensation (PLS) and phantom limb pain (PLP) in children and young adults suffering landmine-related amputation. Materials & Methods All youths with amputation due to landmine explosions participated in this study. The proportions of patients with phantom limb sensation/pain, intensity and frequency of pain were reported. Chi square test was used to examine the relationship between variables. Comparison of PLP and PLS between upper and lower amputation was done by unpaired t-test. Results There were 38 male and 3 female with the mean age of 15.8±2.4yr. The mean interval between injury and follow-up was 90.7±39.6 months. Twelve (44.4%) upper limb amputees and 11 (26.8%) lower limb amputees had PLS. Nine (33.3%) upper limb amputees and 7 (17.1%) lower limb amputees experienced PLP. Of 27 upper limb amputees, 6 (14.6%) and among 15 lower limb amputees, 6 (14.6%) had both PLS and PLP. One case suffered amputation of upper and lower limbs and was experiencing PLS and PLP in both parts. PLS had a significant difference between the upper and lower amputated groups. Significant relationship was observed between age of casualty and duration of injury with PLP. Conclusion Phantom limb sensation and pain in young survivors of landmine explosions appear to be common, even years after amputation. PMID:27375755

  7. Adult Education and the Human Environment: Transactions of a Celebration.

    ERIC Educational Resources Information Center

    Jones-Quartey, K. A. B., Ed.; And Others

    The document comprises a collection of speeches and seminar reports arising from the 25th anniversary celebration of the Institute of Adult Education at the University of Ghana. The theme of the celebration, introduced in the first chapter, was Adult Education and Man's Environment--the Next Quarter-Century. The second chapter comprises the…

  8. A Wearable Goggle Navigation System for Dual-Mode Optical and Ultrasound Localization of Suspicious Lesions: Validation Studies Using Tissue-Simulating Phantoms and an Ex Vivo Human Breast Tissue Model

    PubMed Central

    Wang, Dong; Gan, Qi; Ye, Jian; Yue, Jian; Wang, Benzhong; Povoski, Stephen P.; Martin, Edward W.; Hitchcock, Charles L.; Yilmaz, Alper; Tweedle, Michael F.; Shao, Pengfei; Xu, Ronald X.

    2016-01-01

    Surgical resection remains the primary curative treatment for many early-stage cancers, including breast cancer. The development of intraoperative guidance systems for identifying all sites of disease and improving the likelihood of complete surgical resection is an area of active ongoing research, as this can lead to a decrease in the need of subsequent additional surgical procedures. We develop a wearable goggle navigation system for dual-mode optical and ultrasound imaging of suspicious lesions. The system consists of a light source module, a monochromatic CCD camera, an ultrasound system, a Google Glass, and a host computer. It is tested in tissue-simulating phantoms and an ex vivo human breast tissue model. Our experiments demonstrate that the surgical navigation system provides useful guidance for localization and core needle biopsy of simulated tumor within the tissue-simulating phantom, as well as a core needle biopsy and subsequent excision of Indocyanine Green (ICG)—fluorescing sentinel lymph nodes. Our experiments support the contention that this wearable goggle navigation system can be potentially very useful and fully integrated by the surgeon for optimizing many aspects of oncologic surgery. Further engineering optimization and additional in vivo clinical validation work is necessary before such a surgical navigation system can be fully realized in the everyday clinical setting. PMID:27367051

  9. Transcriptional profiling of adult neural stem-like cells from the human brain.

    PubMed

    Sandberg, Cecilie Jonsgar; Vik-Mo, Einar O; Behnan, Jinan; Helseth, Eirik; Langmoen, Iver A

    2014-01-01

    There is a great potential for the development of new cell replacement strategies based on adult human neural stem-like cells. However, little is known about the hierarchy of cells and the unique molecular properties of stem- and progenitor cells of the nervous system. Stem cells from the adult human brain can be propagated and expanded in vitro as free floating neurospheres that are capable of self-renewal and differentiation into all three cell types of the central nervous system. Here we report the first global gene expression study of adult human neural stem-like cells originating from five human subventricular zone biopsies (mean age 42, range 33-60). Compared to adult human brain tissue, we identified 1,189 genes that were significantly up- and down-regulated in adult human neural stem-like cells (1% false discovery rate). We found that adult human neural stem-like cells express stem cell markers and have reduced levels of markers that are typical of the mature cells in the nervous system. We report that the genes being highly expressed in adult human neural stem-like cells are associated with developmental processes and the extracellular region of the cell. The calcium signaling pathway and neuroactive ligand-receptor interactions are enriched among the most differentially regulated genes between adult human neural stem-like cells and adult human brain tissue. We confirmed the expression of 10 of the most up-regulated genes in adult human neural stem-like cells in an additional sample set that included adult human neural stem-like cells (n = 6), foetal human neural stem cells (n = 1) and human brain tissues (n = 12). The NGFR, SLITRK6 and KCNS3 receptors were further investigated by immunofluorescence and shown to be heterogeneously expressed in spheres. These receptors could potentially serve as new markers for the identification and characterisation of neural stem- and progenitor cells or as targets for manipulation of cellular fate.

  10. Transcriptional Profiling of Adult Neural Stem-Like Cells from the Human Brain

    PubMed Central

    Sandberg, Cecilie Jonsgar; Vik-Mo, Einar O.; Behnan, Jinan; Helseth, Eirik; Langmoen, Iver A.

    2014-01-01

    There is a great potential for the development of new cell replacement strategies based on adult human neural stem-like cells. However, little is known about the hierarchy of cells and the unique molecular properties of stem- and progenitor cells of the nervous system. Stem cells from the adult human brain can be propagated and expanded in vitro as free floating neurospheres that are capable of self-renewal and differentiation into all three cell types of the central nervous system. Here we report the first global gene expression study of adult human neural stem-like cells originating from five human subventricular zone biopsies (mean age 42, range 33–60). Compared to adult human brain tissue, we identified 1,189 genes that were significantly up- and down-regulated in adult human neural stem-like cells (1% false discovery rate). We found that adult human neural stem-like cells express stem cell markers and have reduced levels of markers that are typical of the mature cells in the nervous system. We report that the genes being highly expressed in adult human neural stem-like cells are associated with developmental processes and the extracellular region of the cell. The calcium signaling pathway and neuroactive ligand-receptor interactions are enriched among the most differentially regulated genes between adult human neural stem-like cells and adult human brain tissue. We confirmed the expression of 10 of the most up-regulated genes in adult human neural stem-like cells in an additional sample set that included adult human neural stem-like cells (n = 6), foetal human neural stem cells (n = 1) and human brain tissues (n = 12). The NGFR, SLITRK6 and KCNS3 receptors were further investigated by immunofluorescence and shown to be heterogeneously expressed in spheres. These receptors could potentially serve as new markers for the identification and characterisation of neural stem- and progenitor cells or as targets for manipulation of cellular fate. PMID

  11. Rapid prototyping of biomimetic vascular phantoms for hyperspectral reflectance imaging.

    PubMed

    Ghassemi, Pejhman; Wang, Jianting; Melchiorri, Anthony J; Ramella-Roman, Jessica C; Mathews, Scott A; Coburn, James C; Sorg, Brian S; Chen, Yu; Pfefer, T Joshua

    2015-01-01

    The emerging technique of rapid prototyping with three-dimensional (3-D) printers provides a simple yet revolutionary method for fabricating objects with arbitrary geometry. The use of 3-D printing for generating morphologically biomimetic tissue phantoms based on medical images represents a potentially major advance over existing phantom approaches. Toward the goal of image-defined phantoms, we converted a segmented fundus image of the human retina into a matrix format and edited it to achieve a geometry suitable for printing. Phantoms with vessel-simulating channels were then printed using a photoreactive resin providing biologically relevant turbidity, as determined by spectrophotometry. The morphology of printed vessels was validated by x-ray microcomputed tomography. Channels were filled with hemoglobin (Hb) solutions undergoing desaturation, and phantoms were imaged with a near-infrared hyperspectral reflectance imaging system. Additionally, a phantom was printed incorporating two disjoint vascular networks at different depths, each filled with Hb solutions at different saturation levels. Light propagation effects noted during these measurements—including the influence of vessel density and depth on Hb concentration and saturation estimates, and the effect of wavelength on vessel visualization depth—were evaluated. Overall, our findings indicated that 3-D-printed biomimetic phantoms hold significant potential as realistic and practical tools for elucidating light–tissue interactions and characterizing biophotonic system performance. PMID:26662064

  12. Rapid prototyping of biomimetic vascular phantoms for hyperspectral reflectance imaging

    NASA Astrophysics Data System (ADS)

    Ghassemi, Pejhman; Wang, Jianting; Melchiorri, Anthony J.; Ramella-Roman, Jessica C.; Mathews, Scott A.; Coburn, James C.; Sorg, Brian S.; Chen, Yu; Joshua Pfefer, T.

    2015-12-01

    The emerging technique of rapid prototyping with three-dimensional (3-D) printers provides a simple yet revolutionary method for fabricating objects with arbitrary geometry. The use of 3-D printing for generating morphologically biomimetic tissue phantoms based on medical images represents a potentially major advance over existing phantom approaches. Toward the goal of image-defined phantoms, we converted a segmented fundus image of the human retina into a matrix format and edited it to achieve a geometry suitable for printing. Phantoms with vessel-simulating channels were then printed using a photoreactive resin providing biologically relevant turbidity, as determined by spectrophotometry. The morphology of printed vessels was validated by x-ray microcomputed tomography. Channels were filled with hemoglobin (Hb) solutions undergoing desaturation, and phantoms were imaged with a near-infrared hyperspectral reflectance imaging system. Additionally, a phantom was printed incorporating two disjoint vascular networks at different depths, each filled with Hb solutions at different saturation levels. Light propagation effects noted during these measurements-including the influence of vessel density and depth on Hb concentration and saturation estimates, and the effect of wavelength on vessel visualization depth-were evaluated. Overall, our findings indicated that 3-D-printed biomimetic phantoms hold significant potential as realistic and practical tools for elucidating light-tissue interactions and characterizing biophotonic system performance.

  13. Germline stem cells and neo-oogenesis in the adult human ovary.

    PubMed

    Liu, Yifei; Wu, Chao; Lyu, Qifeng; Yang, Dongzi; Albertini, David F; Keefe, David L; Liu, Lin

    2007-06-01

    It remains unclear whether neo-oogenesis occurs in postnatal ovaries of mammals, based on studies in mice. We thought to test whether adult human ovaries contain germline stem cells (GSCs) and undergo neo-oogenesis. Rather than using genetic manipulation which is unethical in humans, we took the approach of analyzing the expression of meiotic marker genes and genes for germ cell proliferation, which are required for neo-oogenesis, in adult human ovaries covering an age range from 28 to 53 years old, compared to testis and fetal ovaries served as positive controls. We show that active meiosis, neo-oogenesis and GSCs are unlikely to exist in normal, adult, human ovaries. No early meiotic-specific or oogenesis-associated mRNAs for SPO11, PRDM9, SCP1, TERT and NOBOX were detectable in adult human ovaries using RT-PCR, compared to fetal ovary and adult testis controls. These findings are further corroborated by the absence of early meiocytes and proliferating germ cells in adult human ovarian cortex probed with markers for meiosis (SCP3), oogonium (OCT3/4, c-KIT), and cell cycle progression (Ki-67, PCNA), in contrast to fetal ovary controls. If postnatal oogenesis is confirmed in mice, then this species would represent an exception to the rule that neo-oogenesis does not occur in adults.

  14. A comparison of erythrocyte glutathione S-transferase activity from human foetuses and adults.

    PubMed Central

    Strange, R C; Johnston, J D; Coghill, D R; Hume, R

    1980-01-01

    Glutathione S-transferase activity was measured in partially purified haemolysates of erythrocytes from human foetuses and adults. Enzyme activity was present in erythrocytes obtained between 12 and 40 weeks of gestation. The catalytic properties of the enzyme from foetal cells were similar to those of the enzyme from adult erythrocytes, indicating that probably only one form of the erythrocytes enzyme exists throughout foetal and adult life. PMID:7396875

  15. Brain stem auditory evoked responses in human infants and adults

    NASA Technical Reports Server (NTRS)

    Hecox, K.; Galambos, R.

    1974-01-01

    Brain stem evoked potentials were recorded by conventional scalp electrodes in infants (3 weeks to 3 years of age) and adults. The latency of one of the major response components (wave V) is shown to be a function both of click intensity and the age of the subject; this latency at a given signal strength shortens postnatally to reach the adult value (about 6 msec) by 12 to 18 months of age. The demonstrated reliability and limited variability of these brain stem electrophysiological responses provide the basis for an optimistic estimate of their usefulness as an objective method for assessing hearing in infants and adults.

  16. Adult Continuing Education and Human Resource Development: Present Competitors, Potential Partners

    ERIC Educational Resources Information Center

    Smith, Douglas H.

    2006-01-01

    Adult Continuing Education (ACE) and Human Resource Development (HRD) have grown tremendously in the last quarter century. ACE experienced tremendous growth in the 60s and 70s, with over 17 million attending colleges and universities, and local school and community adult education programs by the end of the 1970s. More ACE programs were started…

  17. Reaching beyond the United States: Adventures in International Adult Education and Human Resource Development

    ERIC Educational Resources Information Center

    Henschke, John A.

    2005-01-01

    In this article, the author shares his experience of how travel and adult education merged, for him, into a major emphasis in international adult education (AE) and human resource development (HRD). International ventures have been some of the most exciting and learning-filled aspects of the author's career in AE and HRD. His involvement in…

  18. Organ shielding and doses in Low-Earth orbit calculated for spherical and anthropomorphic phantoms

    NASA Astrophysics Data System (ADS)

    Matthiä, Daniel; Berger, Thomas; Reitz, Günther

    2013-08-01

    Humans in space are exposed to elevated levels of radiation compared to ground. Different sources contribute to the total exposure with galactic cosmic rays being the most important component. The application of numerical and anthropomorphic phantoms in simulations allows the estimation of dose rates from galactic cosmic rays in individual organs and whole body quantities such as the effective dose. The male and female reference phantoms defined by the International Commission on Radiological Protection and the hermaphrodite numerical RANDO phantom are voxel implementations of anthropomorphic phantoms and contain all organs relevant for radiation risk assessment. These anthropomorphic phantoms together with a spherical water phantom were used in this work to translate the mean shielding of organs in the different anthropomorphic voxel phantoms into positions in the spherical phantom. This relation allows using a water sphere as surrogate for the anthropomorphic phantoms in both simulations and measurements. Moreover, using spherical phantoms in the calculation of radiation exposure offers great advantages over anthropomorphic phantoms in terms of computational time. In this work, the mean shielding of organs in the different voxel phantoms exposed to isotropic irradiation is presented as well as the corresponding depth in a water sphere. Dose rates for Low-Earth orbit from galactic cosmic rays during solar minimum conditions were calculated using the different phantoms and are compared to the results for a spherical water phantom in combination with the mean organ shielding. For the spherical water phantom the impact of different aluminium shielding between 1 g/cm2 and 100 g/cm2 was calculated. The dose equivalent rates were used to estimate the effective dose rate.

  19. Newborn human skin fibroblasts senesce in vitro without acquiring adult growth factor requirements

    SciTech Connect

    Wharton, W.

    1984-01-01

    Cultures of human fibroblasts were prepared from chest skin obtained either from newborns (less than 3 months old) or adults (more than 35 years old) and maintained in vitro until they senesced. Adult cells grew logarithmically in medium supplemented with whole blood serum but not with platelet-poor plasma. Early passage cells obtained from newborns grew equally well in either plasma- or serum-supplemented medium. The difference in growth factor requirements between adult and newborn cells persisted through the lifespan of the cells; i.e., newborn cells did not develop adult hormonal requirements when maintained in culture. Thus, in vitro cellular aging can be distinguished from some types of differentiation.

  20. A methodology to develop computational phantoms with adjustable posture for WBC calibration

    NASA Astrophysics Data System (ADS)

    Ferreira Fonseca, T. C.; Bogaerts, R.; Hunt, John; Vanhavere, F.

    2014-11-01

    A Whole Body Counter (WBC) is a facility to routinely assess the internal contamination of exposed workers, especially in the case of radiation release accidents. The calibration of the counting device is usually done by using anthropomorphic physical phantoms representing the human body. Due to such a challenge of constructing representative physical phantoms a virtual calibration has been introduced. The use of computational phantoms and the Monte Carlo method to simulate radiation transport have been demonstrated to be a worthy alternative. In this study we introduce a methodology developed for the creation of realistic computational voxel phantoms with adjustable posture for WBC calibration. The methodology makes use of different software packages to enable the creation and modification of computational voxel phantoms. This allows voxel phantoms to be developed on demand for the calibration of different WBC configurations. This in turn helps to study the major source of uncertainty associated with the in vivo measurement routine which is the difference between the calibration phantoms and the real persons being counted. The use of realistic computational phantoms also helps the optimization of the counting measurement. Open source codes such as MakeHuman and Blender software packages have been used for the creation and modelling of 3D humanoid characters based on polygonal mesh surfaces. Also, a home-made software was developed whose goal is to convert the binary 3D voxel grid into a MCNPX input file. This paper summarizes the development of a library of phantoms of the human body that uses two basic phantoms called MaMP and FeMP (Male and Female Mesh Phantoms) to create a set of male and female phantoms that vary both in height and in weight. Two sets of MaMP and FeMP phantoms were developed and used for efficiency calibration of two different WBC set-ups: the Doel NPP WBC laboratory and AGM laboratory of SCK-CEN in Mol, Belgium.

  1. Organosilicon phantom for photoacoustic imaging

    NASA Astrophysics Data System (ADS)

    Avigo, Cinzia; Di Lascio, Nicole; Armanetti, Paolo; Kusmic, Claudia; Cavigli, Lucia; Ratto, Fulvio; Meucci, Sandro; Masciullo, Cecilia; Cecchini, Marco; Pini, Roberto; Faita, Francesco; Menichetti, Luca

    2015-04-01

    Photoacoustic imaging is an emerging technique. Although commercially available photoacoustic imaging systems currently exist, the technology is still in its infancy. Therefore, the design of stable phantoms is essential to achieve semiquantitative evaluation of the performance of a photoacoustic system and can help optimize the properties of contrast agents. We designed and developed a polydimethylsiloxane (PDMS) phantom with exceptionally fine geometry; the phantom was tested using photoacoustic experiments loaded with the standard indocyanine green dye and compared to an agar phantom pattern through polyethylene glycol-gold nanorods. The linearity of the photoacoustic signal with the nanoparticle number was assessed. The signal-to-noise ratio and contrast were employed as image quality parameters, and enhancements of up to 50 and up to 300%, respectively, were measured with the PDMS phantom with respect to the agar one. A tissue-mimicking (TM)-PDMS was prepared by adding TiO2 and India ink; photoacoustic tests were performed in order to compare the signal generated by the TM-PDMS and the biological tissue. The PDMS phantom can become a particularly promising tool in the field of photoacoustics for the evaluation of the performance of a PA system and as a model of the structure of vascularized soft tissues.

  2. Phantom stars and topology change

    SciTech Connect

    DeBenedictis, Andrew; Garattini, Remo; Lobo, Francisco S. N.

    2008-11-15

    In this work, we consider time-dependent dark-energy star models, with an evolving parameter {omega} crossing the phantom divide {omega}=-1. Once in the phantom regime, the null energy condition is violated, which physically implies that the negative radial pressure exceeds the energy density. Therefore, an enormous negative pressure in the center may, in principle, imply a topology change, consequently opening up a tunnel and converting the dark-energy star into a wormhole. The criteria for this topology change are discussed and, in particular, we consider a Casimir energy approach involving quasilocal energy difference calculations that may reflect or measure the occurrence of a topology change. We denote these exotic geometries consisting of dark-energy stars (in the phantom regime) and phantom wormholes as phantom stars. The final product of this topological change, namely, phantom wormholes, have far-reaching physical and cosmological implications, as in addition to being used for interstellar shortcuts, an absurdly advanced civilization may manipulate these geometries to induce closed timelike curves, consequently violating causality.

  3. Organosilicon phantom for photoacoustic imaging.

    PubMed

    Avigo, Cinzia; Di Lascio, Nicole; Armanetti, Paolo; Kusmic, Claudia; Cavigli, Lucia; Ratto, Fulvio; Meucci, Sandro; Masciullo, Cecilia; Cecchini, Marco; Pini, Roberto; Faita, Francesco; Menichetti, Luca

    2015-04-01

    Photoacoustic imaging is an emerging technique. Although commercially available photoacoustic imaging systems currently exist, the technology is still in its infancy. Therefore, the design of stable phantoms is essential to achieve semiquantitative evaluation of the performance of a photoacoustic system and can help optimize the properties of contrast agents. We designed and developed a polydimethylsiloxane (PDMS) phantom with exceptionally fine geometry; the phantom was tested using photoacoustic experiments loaded with the standard indocyanine green dye and compared to an agar phantom pattern through polyethylene glycol-gold nanorods. The linearity of the photoacoustic signal with the nanoparticle number was assessed. The signal-tonoiseratio and contrast were employed as image quality parameters, and enhancements of up to 50 and up to 300%, respectively, were measured with the PDMS phantom with respect to the agar one. A tissue-mimicking (TM)-PDMS was prepared by adding TiO2 and India ink; photoacoustic tests were performed in order to compare the signal generated by the TM-PDMS and the biological tissue. The PDMS phantom can become a particularly promising tool in the field of photoacoustics for the evaluation of the performance of a PA system and as a model of the structure of vascularized soft tissues.

  4. Automatic Synthesis of Anthropomorphic Pulmonary CT Phantoms

    PubMed Central

    Jimenez-Carretero, Daniel; San Jose Estepar, Raul; Diaz Cacio, Mario; Ledesma-Carbayo, Maria J.

    2016-01-01

    The great density and structural complexity of pulmonary vessels and airways impose limitations on the generation of accurate reference standards, which are critical in training and in the validation of image processing methods for features such as pulmonary vessel segmentation or artery–vein (AV) separations. The design of synthetic computed tomography (CT) images of the lung could overcome these difficulties by providing a database of pseudorealistic cases in a constrained and controlled scenario where each part of the image is differentiated unequivocally. This work demonstrates a complete framework to generate computational anthropomorphic CT phantoms of the human lung automatically. Starting from biological and image-based knowledge about the topology and relationships between structures, the system is able to generate synthetic pulmonary arteries, veins, and airways using iterative growth methods that can be merged into a final simulated lung with realistic features. A dataset of 24 labeled anthropomorphic pulmonary CT phantoms were synthesized with the proposed system. Visual examination and quantitative measurements of intensity distributions, dispersion of structures and relationships between pulmonary air and blood flow systems show good correspondence between real and synthetic lungs (p > 0.05 with low Cohen’s d effect size and AUC values), supporting the potentiality of the tool and the usefulness of the generated phantoms in the biomedical image processing field. PMID:26731653

  5. Investigation of genes important in neurodevelopment disorders in adult human brain.

    PubMed

    Maussion, Gilles; Diallo, Alpha B; Gigek, Carolina O; Chen, Elizabeth S; Crapper, Liam; Théroux, Jean-Francois; Chen, Gary G; Vasuta, Cristina; Ernst, Carl

    2015-10-01

    Several neurodevelopmental disorders (NDDs) are caused by mutations in genes expressed in fetal brain, but little is known about these same genes in adult human brain. Here, we test the hypothesis that genes associated with NDDs continue to have a role in adult human brain to explore the idea that NDD symptoms may be partially a result of their adult function rather than just their neurodevelopmental function. To demonstrate adult brain function, we performed expression analyses and ChIPseq in human neural stem cell(NSC) lines at different developmental stages and adult human brain, targeting two genes associated with NDDs, SATB2 and EHMT1, and the WNT signaling gene TCF7L2, which has not been associated with NDDs. Analysis of DNA interaction sites in neural stem cells reveals high (40-50 %) overlap between proliferating and differentiating cells for each gene in temporal space. Studies in adult brain demonstrate that consensus sites are similar to NSCs but occur at different genomic locations. We also performed expression analyses using BrainSpan data for NDD-associated genes SATB2, EHMT1, FMR1, MECP2, MBD5, CTNND2, RAI1, CHD8, GRIN2A, GRIN2B, TCF4, SCN2A, and DYRK1A and find high expression of these genes in adult brain, at least comparable to developing human brain, confirming that genes associated with NDDs likely have a role in adult tissue. Adult function of genes associated with NDDs might be important in clinical disease presentation and may be suitable targets for therapeutic intervention. PMID:26194112

  6. Investigation of genes important in neurodevelopment disorders in adult human brain.

    PubMed

    Maussion, Gilles; Diallo, Alpha B; Gigek, Carolina O; Chen, Elizabeth S; Crapper, Liam; Théroux, Jean-Francois; Chen, Gary G; Vasuta, Cristina; Ernst, Carl

    2015-10-01

    Several neurodevelopmental disorders (NDDs) are caused by mutations in genes expressed in fetal brain, but little is known about these same genes in adult human brain. Here, we test the hypothesis that genes associated with NDDs continue to have a role in adult human brain to explore the idea that NDD symptoms may be partially a result of their adult function rather than just their neurodevelopmental function. To demonstrate adult brain function, we performed expression analyses and ChIPseq in human neural stem cell(NSC) lines at different developmental stages and adult human brain, targeting two genes associated with NDDs, SATB2 and EHMT1, and the WNT signaling gene TCF7L2, which has not been associated with NDDs. Analysis of DNA interaction sites in neural stem cells reveals high (40-50 %) overlap between proliferating and differentiating cells for each gene in temporal space. Studies in adult brain demonstrate that consensus sites are similar to NSCs but occur at different genomic locations. We also performed expression analyses using BrainSpan data for NDD-associated genes SATB2, EHMT1, FMR1, MECP2, MBD5, CTNND2, RAI1, CHD8, GRIN2A, GRIN2B, TCF4, SCN2A, and DYRK1A and find high expression of these genes in adult brain, at least comparable to developing human brain, confirming that genes associated with NDDs likely have a role in adult tissue. Adult function of genes associated with NDDs might be important in clinical disease presentation and may be suitable targets for therapeutic intervention.

  7. The Human Function Compunction: Teleological Explanation in Adults

    ERIC Educational Resources Information Center

    Kelemen, Deborah; Rosset, Evelyn

    2009-01-01

    Research has found that children possess a broad bias in favor of teleological--or purpose-based--explanations of natural phenomena. The current two experiments explored whether adults implicitly possess a similar bias. In Study 1, undergraduates judged a series of statements as "good" (i.e., correct) or "bad" (i.e., incorrect) explanations for…

  8. 21 CFR 892.1950 - Radiographic anthropomorphic phantom.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiographic anthropomorphic phantom. 892.1950 Section 892.1950 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... purposes to simulate a human body for positioning radiographic equipment. (b) Classification. Class...

  9. Phantom black holes and sigma models

    SciTech Connect

    Azreg-Aienou, Mustapha; Clement, Gerard; Fabris, Julio C.; Rodrigues, Manuel E.

    2011-06-15

    We construct static multicenter solutions of phantom Einstein-Maxwell-dilaton theory from null geodesics of the target space, leading to regular black holes without spatial symmetry for certain discrete values of the dilaton coupling constant. We also discuss the three-dimensional gravitating sigma models obtained by reduction of phantom Einstein-Maxwell, phantom Kaluza-Klein and phantom Einstein-Maxwell-dilaton-axion theories. In each case, we generate by group transformations phantom charged black hole solutions from a neutral seed.

  10. Teaching Adults with Learning Disabilities. Professional Practices in Adult Education and Human Resource Development Series.

    ERIC Educational Resources Information Center

    Jordan, Dale R.

    This book is designed to show teachers how to reach out to adults and adolescents with learning disabilities and employ specific strategies for helping them to compensate for the disabilities and acquire literacy skills. The ways in which specific differences in brain structure inhibit the mastery of reading, spelling, handwriting, phonics, and…

  11. Anthropomorphic Phantoms for Confirmation of Linear Accelerator-Based Small Animal Irradiation.

    PubMed

    Perks, Julian R; Lucero, Steven; Monjazeb, Arta M; Li, Jian Jian

    2015-03-01

    Three dimensional (3D) scanning and printing technology is utilized to create phantom models of mice in order to assess the accuracy of ionizing radiation dosing from a clinical, human-based linear accelerator. Phantoms are designed to simulate a range of research questions, including irradiation of lung tumors and primary subcutaneous or orthotopic tumors for immunotherapy experimentation. The phantoms are used to measure the accuracy of dose delivery and then refine it to within 1% of the prescribed dose.

  12. Heterogeneous Breast Phantom Development for Microwave Imaging Using Regression Models

    PubMed Central

    Hahn, Camerin; Noghanian, Sima

    2012-01-01

    As new algorithms for microwave imaging emerge, it is important to have standard accurate benchmarking tests. Currently, most researchers use homogeneous phantoms for testing new algorithms. These simple structures lack the heterogeneity of the dielectric properties of human tissue and are inadequate for testing these algorithms for medical imaging. To adequately test breast microwave imaging algorithms, the phantom has to resemble different breast tissues physically and in terms of dielectric properties. We propose a systematic approach in designing phantoms that not only have dielectric properties close to breast tissues but also can be easily shaped to realistic physical models. The approach is based on regression model to match phantom's dielectric properties with the breast tissue dielectric properties found in Lazebnik et al. (2007). However, the methodology proposed here can be used to create phantoms for any tissue type as long as ex vivo, in vitro, or in vivo tissue dielectric properties are measured and available. Therefore, using this method, accurate benchmarking phantoms for testing emerging microwave imaging algorithms can be developed. PMID:22550473

  13. A biological phantom for evaluation of CT image reconstruction algorithms

    NASA Astrophysics Data System (ADS)

    Cammin, J.; Fung, G. S. K.; Fishman, E. K.; Siewerdsen, J. H.; Stayman, J. W.; Taguchi, K.

    2014-03-01

    In recent years, iterative algorithms have become popular in diagnostic CT imaging to reduce noise or radiation dose to the patient. The non-linear nature of these algorithms leads to non-linearities in the imaging chain. However, the methods to assess the performance of CT imaging systems were developed assuming the linear process of filtered backprojection (FBP). Those methods may not be suitable any longer when applied to non-linear systems. In order to evaluate the imaging performance, a phantom is typically scanned and the image quality is measured using various indices. For reasons of practicality, cost, and durability, those phantoms often consist of simple water containers with uniform cylinder inserts. However, these phantoms do not represent the rich structure and patterns of real tissue accurately. As a result, the measured image quality or detectability performance for lesions may not reflect the performance on clinical images. The discrepancy between estimated and real performance may be even larger for iterative methods which sometimes produce "plastic-like", patchy images with homogeneous patterns. Consequently, more realistic phantoms should be used to assess the performance of iterative algorithms. We designed and constructed a biological phantom consisting of porcine organs and tissue that models a human abdomen, including liver lesions. We scanned the phantom on a clinical CT scanner and compared basic image quality indices between filtered backprojection and an iterative reconstruction algorithm.

  14. On the dose sensitivity of a new CDMAM phantom

    NASA Astrophysics Data System (ADS)

    Figl, M.; Semturs, F.; Kaar, M.; Hoffmann, R.; Floor-Westerdijk, M.; van der Burght, R.; Homolka, P.; Hummel, J.

    2015-05-01

    For the technical quality assurance of breast cancer screening protocols several phantoms have been developed. Their dose sensitivity is a common topic often discussed in literature. The European protocol for the quality control of the physical and technical aspects of mammography screening suggests a contrast-detail phantom like the CDMAM phantom (Artinis Medical Systems, Elst, NL). The CDMAM 3.4 was tested with respect to its dose sensitivity and compared to other phantoms in a recent paper. The CDMAM 4.0 phantom provides other disc diameters and thicknesses adapted more closely to the image quality found in modern mammography systems. This motivates a comparison of the two generations using the same exposure parameters. We varied the time-current (mAs) within a range of clinically used values (40-140 mAs). All evaluations were done using automatic evaluation software provided by Artinis (for CDMAM 4.0) and the National Coordinating Centre for the Physics of Mammography, Guildford UK (CDMAM 3.4). We compared the relative dose sensitivity with respect to the different diameters and also computed the IQFinv parameter, which averages over the diameters as suggested in the manual for the phantom. The IQFinv parameter linearly depends on dose for both phantoms. The CDMAM 4.0 shows a more monotonous dependence on dose, the total variation of the threshold thicknesses as functions of the dose are significantly smaller than with the CDMAM 3.4. As the automatic evaluation shows rather different threshold thicknesses for the two phantoms, conversion factors for human to automatic readout have to be adapted.

  15. A set of 4D pediatric XCAT reference phantoms for multimodality research

    SciTech Connect

    Norris, Hannah Zhang, Yakun; Bond, Jason; Sturgeon, Gregory M.; Samei, E.; Segars, W. P.; Minhas, Anum; Frush, D.; Tward, Daniel J.; Ratnanather, J. T.; Miller, M. I.

    2014-03-15

    Purpose: The authors previously developed an adult population of 4D extended cardiac-torso (XCAT) phantoms for multimodality imaging research. In this work, the authors develop a reference set of 4D pediatric XCAT phantoms consisting of male and female anatomies at ages of newborn, 1, 5, 10, and 15 years. These models will serve as the foundation from which the authors will create a vast population of pediatric phantoms for optimizing pediatric CT imaging protocols. Methods: Each phantom was based on a unique set of CT data from a normal patient obtained from the Duke University database. The datasets were selected to best match the reference values for height and weight for the different ages and genders according to ICRP Publication 89. The major organs and structures were segmented from the CT data and used to create an initial pediatric model defined using nonuniform rational B-spline surfaces. The CT data covered the entire torso and part of the head. To complete the body, the authors manually added on the top of the head and the arms and legs using scaled versions of the XCAT adult models or additional models created from cadaver data. A multichannel large deformation diffeomorphic metric mapping algorithm was then used to calculate the transform from a template XCAT phantom (male or female 50th percentile adult) to the target pediatric model. The transform was applied to the template XCAT to fill in any unsegmented structures within the target phantom and to implement the 4D cardiac and respiratory models in the new anatomy. The masses of the organs in each phantom were matched to the reference values given in ICRP Publication 89. The new reference models were checked for anatomical accuracy via visual inspection. Results: The authors created a set of ten pediatric reference phantoms that have the same level of detail and functionality as the original XCAT phantom adults. Each consists of thousands of anatomical structures and includes parameterized models

  16. A set of 4D pediatric XCAT reference phantoms for multimodality research

    PubMed Central

    Norris, Hannah; Zhang, Yakun; Bond, Jason; Sturgeon, Gregory M.; Minhas, Anum; Tward, Daniel J.; Ratnanather, J. T.; Miller, M. I.; Frush, D.; Samei, E.; Segars, W. P.

    2014-01-01

    Purpose: The authors previously developed an adult population of 4D extended cardiac-torso (XCAT) phantoms for multimodality imaging research. In this work, the authors develop a reference set of 4D pediatric XCAT phantoms consisting of male and female anatomies at ages of newborn, 1, 5, 10, and 15 years. These models will serve as the foundation from which the authors will create a vast population of pediatric phantoms for optimizing pediatric CT imaging protocols. Methods: Each phantom was based on a unique set of CT data from a normal patient obtained from the Duke University database. The datasets were selected to best match the reference values for height and weight for the different ages and genders according to ICRP Publication 89. The major organs and structures were segmented from the CT data and used to create an initial pediatric model defined using nonuniform rational B-spline surfaces. The CT data covered the entire torso and part of the head. To complete the body, the authors manually added on the top of the head and the arms and legs using scaled versions of the XCAT adult models or additional models created from cadaver data. A multichannel large deformation diffeomorphic metric mapping algorithm was then used to calculate the transform from a template XCAT phantom (male or female 50th percentile adult) to the target pediatric model. The transform was applied to the template XCAT to fill in any unsegmented structures within the target phantom and to implement the 4D cardiac and respiratory models in the new anatomy. The masses of the organs in each phantom were matched to the reference values given in ICRP Publication 89. The new reference models were checked for anatomical accuracy via visual inspection. Results: The authors created a set of ten pediatric reference phantoms that have the same level of detail and functionality as the original XCAT phantom adults. Each consists of thousands of anatomical structures and includes parameterized models

  17. The human function compunction: teleological explanation in adults.

    PubMed

    Kelemen, Deborah; Rosset, Evelyn

    2009-04-01

    Research has found that children possess a broad bias in favor of teleological--or purpose-based--explanations of natural phenomena. The current two experiments explored whether adults implicitly possess a similar bias. In Study 1, undergraduates judged a series of statements as "good" (i.e., correct) or "bad" (i.e., incorrect) explanations for why different phenomena occur. Judgments occurred in one of three conditions: fast speeded, moderately speeded, or unspeeded. Participants in speeded conditions judged significantly more scientifically unwarranted teleological explanations as correct (e.g., "the sun radiates heat because warmth nurtures life"), but were not more error-prone on control items (e.g., unwarranted physical explanations such as "hills form because floodwater freezes"). Study 2 extended these findings by examining the relationship between different aspects of adults' "promiscuous teleology" and other variables such as scientific knowledge, religious beliefs, and inhibitory control. Implications of these findings for scientific literacy are discussed. PMID:19200537

  18. A novel composite material specifically developed for ultrasound bone phantoms: cortical, trabecular and skull.

    PubMed

    Wydra, A; Maev, R Gr

    2013-11-21

    In the various stages of developing diagnostic and therapeutic equipment, the use of phantoms can play a very important role in improving the process, help in implementation, testing and calibrations. Phantoms are especially useful in developing new applications and training new doctors in medical schools. However, devices that use different physical factors, such as MRI, Ultrasound, CT Scan, etc will require the phantom to be made of different physical properties. In this paper we introduce the properties of recently designed new materials for developing phantoms for ultrasonic human body investigation, which in today's market make up more than 30% in the world of phantoms. We developed a novel composite material which allows fabrication of various kinds of ultrasound bone phantoms to mimic most of the acoustical properties of human bones. In contrast to the ex vivo tissues, the proposed material can maintain the physical and acoustical properties unchanged for long periods of time; moreover, these properties can be custom designed and created to suit specific needs. As a result, we introduce three examples of ultrasound phantoms that we manufactured in our laboratory: cortical, trabecular and skull bone phantoms. The paper also presents the results of a comparison study between the acoustical and physical properties of actual human bones (reported in the referenced literatures) and the phantoms manufactured by us.

  19. A novel composite material specifically developed for ultrasound bone phantoms: cortical, trabecular and skull

    NASA Astrophysics Data System (ADS)

    Wydra, A.; Maev, R. Gr

    2013-11-01

    In the various stages of developing diagnostic and therapeutic equipment, the use of phantoms can play a very important role in improving the process, help in implementation, testing and calibrations. Phantoms are especially useful in developing new applications and training new doctors in medical schools. However, devices that use different physical factors, such as MRI, Ultrasound, CT Scan, etc will require the phantom to be made of different physical properties. In this paper we introduce the properties of recently designed new materials for developing phantoms for ultrasonic human body investigation, which in today's market make up more than 30% in the world of phantoms. We developed a novel composite material which allows fabrication of various kinds of ultrasound bone phantoms to mimic most of the acoustical properties of human bones. In contrast to the ex vivo tissues, the proposed material can maintain the physical and acoustical properties unchanged for long periods of time; moreover, these properties can be custom designed and created to suit specific needs. As a result, we introduce three examples of ultrasound phantoms that we manufactured in our laboratory: cortical, trabecular and skull bone phantoms. The paper also presents the results of a comparison study between the acoustical and physical properties of actual human bones (reported in the referenced literatures) and the phantoms manufactured by us.

  20. The Adult Learning Disabled Employee: The Organization's Hidden Human Resource.

    ERIC Educational Resources Information Center

    Macomber, Janet A.

    This paper describes an experiment with background material designed to promote problem (learning disabled) employees as human resources rather than rejects. The material is presented in the form of the transcript of a fictional advisory committee meeting attended by the human resources manager, assistant corporate counsel, training director, line…

  1. Adult Education and Human Capital: Leadership from the Fortune 500.

    ERIC Educational Resources Information Center

    Palmer, Teresa M.

    1992-01-01

    A survey of 333 Fortune 500 firms received 81 replies indicating that (1) two-thirds formally recognized the value of human resources; (2) most had changed corporate policy regarding human capital; and (3) most training was provided in the ares of new employee orientation, current job needs, customer relations, personal development, and…

  2. Alternative Sources of Adult Stem Cells: Human Amniotic Membrane

    NASA Astrophysics Data System (ADS)

    Wolbank, Susanne; van Griensven, Martijn; Grillari-Voglauer, Regina; Peterbauer-Scherb, Anja

    Human amniotic membrane is a highly promising cell source for tissue engineering. The cells thereof, human amniotic epithelial cells (hAEC) and human amniotic mesenchymal stromal cells (hAMSC), may be immunoprivileged, they represent an early developmental status, and their application is ethically uncontroversial. Cell banking strategies may use freshly isolated cells or involve in vitro expansion to increase cell numbers. Therefore, we have thoroughly characterized the effect of in vitro cultivation on both phenotype and differentiation potential of hAEC. Moreover, we present different strategies to improve expansion including replacement of animal-derived supplements by human platelet products or the introduction of the catalytic subunit of human telomerase to extend the in vitro lifespan of amniotic cells. Characterization of the resulting cultures includes phenotype, growth characteristics, and differentiation potential, as well as immunogenic and immunomodulatory properties.

  3. SU-F-BRE-04: Construction of 3D Printed Patient Specific Phantoms for Dosimetric Verification Measurements

    SciTech Connect

    Ehler, E; Higgins, P; Dusenbery, K

    2014-06-15

    Purpose: To validate a method to create per patient phantoms for dosimetric verification measurements. Methods: Using a RANDO phantom as a substitute for an actual patient, a model of the external features of the head and neck region of the phantom was created. A phantom was used instead of a human for two reasons: to allow for dosimetric measurements that would not be possible in-vivo and to avoid patient privacy issues. Using acrylonitrile butadiene styrene thermoplastic as the building material, a hollow replica was created using the 3D printer filled with a custom tissue equivalent mixture of paraffin wax, magnesium oxide, and calcium carbonate. A traditional parallel-opposed head and neck plan was constructed. Measurements were performed with thermoluminescent dosimeters in both the RANDO phantom and in the 3D printed phantom. Calculated and measured dose was compared at 17 points phantoms including regions in high and low dose regions and at the field edges. On-board cone beam CT was used to localize both phantoms within 1mm and 1° prior to radiation. Results: The maximum difference in calculated dose between phantoms was 1.8% of the planned dose (180 cGy). The mean difference between calculated and measured dose in the anthropomorphic phantom and the 3D printed phantom was 1.9% ± 2.8% and −0.1% ± 4.9%, respectively. The difference between measured and calculated dose was determined in the RANDO and 3D printed phantoms. The differences between measured and calculated dose in each respective phantom was within 2% for 12 of 17 points. The overlap of the RANDO and 3D printed phantom was 0.956 (Jaccard Index). Conclusion: A custom phantom was created using a 3D printer. Dosimetric calculations and measurements showed good agreement between the dose in the RANDO phantom (patient substitute) and the 3D printed phantom.

  4. Microfluidics based phantoms of superficial vascular network

    PubMed Central

    Luu, Long; Roman, Patrick A.; Mathews, Scott A.; Ramella-Roman, Jessica C.

    2012-01-01

    Several new bio-photonic techniques aim to measure flow in the human vasculature non-destructively. Some of these tools, such as laser speckle imaging or Doppler optical coherence tomography, are now reaching the clinical stage. Therefore appropriate calibration and validation techniques dedicated to these particular measurements are therefore of paramount importance. In this paper we introduce a fast prototyping technique based on laser micromachining for the fabrication of dynamic flow phantoms. Micro-channels smaller than 20 µm in width can be formed in a variety of materials such as epoxies, plastics, and household tape. Vasculature geometries can be easily and quickly modified to accommodate a particular experimental scenario. PMID:22741081

  5. Low abundances of synthetics lipids in phantoms

    NASA Astrophysics Data System (ADS)

    Villanueva-Luna, A. E.; Santiago-Alvarado, A.; Castro-Ramos, J.; Vazquez-Montiel, S.; Flores-Gil, A.; Aguilar-Soto, J.; Delgado-Atencio, J. A.

    2012-03-01

    Phantoms simulate optical characteristics of tissues. Phantoms use to mimic light distributions in living tissue. Several Phantoms compositions made of silicone, polyester, polyurethane, and epoxy resin have been described in the literature. These kinds of phantoms have the problem of long time preservation. In this work, we describe the fabrication and characterization of phantoms with low concentrations of synthetic lipid using Raman spectroscopy. We fabricate four phantoms made of Polydimethylsiloxane (PDMS). These phantoms have synthetic lipid content of cholesterol and triglycerides. The size of our phantoms is 1 x 1 cm and 5 mm of thickness.We used the point-to-point mapping technique. Finally, we compared advantages and performance of made PDMS and gelatin phantoms.

  6. Nasopharyngeal carriage of Streptococcus pneumoniae in adults infected with human immunodeficiency virus in Jakarta, Indonesia.

    PubMed

    Harimurti, Kuntjoro; Saldi, Siti R F; Dewiasty, Esthika; Khoeri, Miftahuddin M; Yunihastuti, Evi; Putri, Tiara; Tafroji, Wisnu; Safari, Dodi

    2016-01-01

    This study investigated the distribution of serotype and antimicrobial susceptibility of Streptococcus pneumoniae carried by adults infected with human immunodeficiency virus (HIV) in Jakarta, Indonesia. Specimens of nasopharyngeal swab were collected from 200 HIV infected adults aged 21 to 63 years. Identification of S. pneumoniae was done by optochin susceptibility test and PCR for the presence of psaA and lytA genes. Serotyping was performed with sequential multiplex PCR and antibiotic susceptibility with the disk diffusion method. S. pneumoniae strains were carried by 10% adults with serotype 6A/B 20% was common serotype among cultured strains in 20 adults. Most of isolates were susceptible to chloramphenicol (80%) followed by clindamycin (75%), erythromycin (75%), penicillin (55%), and tetracycline (50%). This study found resistance to sulphamethoxazole/trimethoprim was most common with only 15% of strains being susceptible. High non-susceptibility to sulphamethoxazole/trimethoprim was observed in S. pneumoniae strains carried by HIV infected adults in Jakarta, Indonesia.

  7. Molecular Mechanism of Adult Neurogenesis and its Association with Human Brain Diseases

    PubMed Central

    Liu, He; Song, Ni

    2016-01-01

    Recent advances in neuroscience challenge the old dogma that neurogenesis occurs only during embryonic development. Mounting evidence suggests that functional neurogenesis occurs throughout adulthood. This review article discusses molecular factors that affect adult neurogenesis, including morphogens, growth factors, neurotransmitters, transcription factors, and epigenetic factors. Furthermore, we summarize and compare current evidence of associations between adult neurogenesis and human brain diseases such as Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, and brain tumors. PMID:27375363

  8. Molecular Mechanism of Adult Neurogenesis and its Association with Human Brain Diseases.

    PubMed

    Liu, He; Song, Ni

    2016-01-01

    Recent advances in neuroscience challenge the old dogma that neurogenesis occurs only during embryonic development. Mounting evidence suggests that functional neurogenesis occurs throughout adulthood. This review article discusses molecular factors that affect adult neurogenesis, including morphogens, growth factors, neurotransmitters, transcription factors, and epigenetic factors. Furthermore, we summarize and compare current evidence of associations between adult neurogenesis and human brain diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and brain tumors. PMID:27375363

  9. [Dietary phytoestrogen and its potential benefits in adult human health].

    PubMed

    Garrido, Argelia; de la Maza, María Pía; Valladares, Luis

    2003-11-01

    Human diet contains a series of bioactive vegetal compounds that can improve human health. Among these, there has been a special interest for phytoestrogens. This article reviews the evidence about the potential benefits of phytoestrogens for human health. Forty eight manuscripts were selected for their study design and relevance to human health. The cell growth inhibitory effects of phytoestrogens and their implication in breast cancer are reviewed. Also the effects of these compounds on serum lipid levels and the effectiveness of a phytoestrogen derivate, ipriflavone, on the prevention of osteoporosis are analyzed. Although these compounds have a great potential for improving health, there is still not enough evidence to recommend the routine use of phytoestrogens.

  10. Cold Preservation of Human Adult Hepatocytes for Liver Cell Therapy.

    PubMed

    Duret, Cedric; Moreno, Daniel; Balasiddaiah, Anangi; Roux, Solene; Briolotti, Phillipe; Raulet, Edith; Herrero, Astrid; Ramet, Helene; Biron-Andreani, Christine; Gerbal-Chaloin, Sabine; Ramos, Jeanne; Navarro, Francis; Hardwigsen, Jean; Maurel, Patrick; Aldabe, Rafael; Daujat-Chavanieu, Martine

    2015-01-01

    Hepatocyte transplantation is a promising alternative therapy for the treatment of hepatic failure, hepatocellular deficiency, and genetic metabolic disorders. Hypothermic preservation of isolated human hepatocytes is potentially a simple and convenient strategy to provide on-demand hepatocytes in sufficient quantity and of the quality required for biotherapy. In this study, first we assessed how cold storage in three clinically safe preservative solutions (UW, HTS-FRS, and IGL-1) affects the viability and in vitro functionality of human hepatocytes. Then we evaluated whether such cold-preserved human hepatocytes could engraft and repopulate damaged livers in a mouse model of liver failure. Human hepatocytes showed comparable viabilities after cold preservation in the three solutions. The ability of fresh and cold-stored hepatocytes to attach to a collagen substratum and to synthesize and secrete albumin, coagulation factor VII, and urea in the medium after 3 days in culture was also equally preserved. Cold-stored hepatocytes were then transplanted in the spleen of immunodeficient mice previously infected with adenoviruses containing a thymidine kinase construct and treated with a single dose of ganciclovir to induce liver injury. Engraftment and liver repopulation were monitored over time by measuring the blood level of human albumin and by assessing the expression of specific human hepatic mRNAs and proteins in the recipient livers by RT-PCR and immunohistochemistry, respectively. Our findings show that cold-stored human hepatocytes in IGL-1 and HTS-FRS preservative solutions can survive, engraft, and proliferate in a damaged mouse liver. These results demonstrate the usefulness of human hepatocyte hypothermic preservation for cell transplantation. PMID:25622096

  11. A century of trends in adult human height.

    PubMed

    2016-07-26

    Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5-22.7) and 16.5 cm (13.3-19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8-144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries.

  12. A century of trends in adult human height

    PubMed Central

    2016-01-01

    Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5–22.7) and 16.5 cm (13.3–19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8–144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries. DOI: http://dx.doi.org/10.7554/eLife.13410.001 PMID:27458798

  13. Resident aerobic microbiota of the adult human nasal cavity.

    PubMed

    Rasmussen, T T; Kirkeby, L P; Poulsen, K; Reinholdt, J; Kilian, M

    2000-10-01

    Recent evidence strongly suggests that the microbiota of the nasal cavity plays a crucial role in determining the reaction patterns of the mucosal and systemic immune system. However, little is known about the normal microbiota of the nasal cavity. The purpose of this study was to determine the microbiota in different parts of the nasal cavity and to develop and evaluate methods for this purpose. Samples were collected from 10 healthy adults by nasal washes and by swabbing of the mucosa through a sterile introduction device. Both methods gave results that were quantitatively and qualitatively reproducible, and revealed significant differences in the density of the nasal microbiota between individuals. The study revealed absence of gram-negative bacteria that are regular members of the commensal microbiota of the pharynx. Likewise, viridans type streptococci were sparsely represented. The nasal microbiota was dominated by species of the genera Corynebacterium, Aureobacterium, Rhodococcus, and Staphylococcus, including S. epidermis, S. capitis, S. hominis, S. haemolyticus, S. lugdunensis and S. warneri. These studies show that the microbiota of the nasal cavity of adults is strikingly different from that of the pharynx, and that the nasal cavity is a primary habitat for several species of diphtheroids recognized as opportunistic pathogens. Under special circumstances, single species, including IgA1 protease-producing bacteria, may become predominant in a restricted area of the nasal mucosa. PMID:11200821

  14. A century of trends in adult human height.

    PubMed

    2016-01-01

    Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5-22.7) and 16.5 cm (13.3-19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8-144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries. PMID:27458798

  15. Variation in thyroid calibration efficiencies as a function of phantom design for I-125

    SciTech Connect

    Miltenberger, R.P.; Langille, E.; Sheetz, M.; Ricci, T.

    1987-01-01

    Four commercially available thyroid phantoms were evaluated to determine the effect that choice of phantom would have on the determination of I-125 activity in the thyroid. Efficiency calibration values for a 5.0-cm diameter 1-mm thick NaI (Tl) detector were determined as a function of distance from the phantom along the central axis and at angles up to 45 off axis using I-125 as the radionuclide of interest. Results indicate that substantial variations in the estimate of radioactivity in the thyroid will occur based on choice of calibration phantom. Using the Humanoid System, Inc. Realistic Phantom as the reference phantom, one could experience differences in estimated activity in the human thyroid that range from 0.86 to 2.94. 6 refs., 6 figs., 3 tabs.

  16. High resolution, MRI-based, segmented, computerized head phantom

    SciTech Connect

    Zubal, I.G.; Harrell, C.R.; Smith, E.O.; Smith, A.L.; Krischlunas, P.

    1999-01-01

    The authors have created a high-resolution software phantom of the human brain which is applicable to voxel-based radiation transport calculations yielding nuclear medicine simulated images and/or internal dose estimates. A software head phantom was created from 124 transverse MRI images of a healthy normal individual. The transverse T2 slices, recorded in a 256x256 matrix from a GE Signa 2 scanner, have isotropic voxel dimensions of 1.5 mm and were manually segmented by the clinical staff. Each voxel of the phantom contains one of 62 index numbers designating anatomical, neurological, and taxonomical structures. The result is stored as a 256x256x128 byte array. Internal volumes compare favorably to those described in the ICRP Reference Man. The computerized array represents a high resolution model of a typical human brain and serves as a voxel-based anthropomorphic head phantom suitable for computer-based modeling and simulation calculations. It offers an improved realism over previous mathematically described software brain phantoms, and creates a reference standard for comparing results of newly emerging voxel-based computations. Such voxel-based computations lead the way to developing diagnostic and dosimetry calculations which can utilize patient-specific diagnostic images. However, such individualized approaches lack fast, automatic segmentation schemes for routine use; therefore, the high resolution, typical head geometry gives the most realistic patient model currently available.

  17. Organ dose conversion coefficients for pediatric reference computational phantoms in external photon radiation fields

    NASA Astrophysics Data System (ADS)

    Chang, Lienard A.

    In the event of a radiological accident or attack, it is important to estimate the organ doses to those exposed. In general, it is difficult to measure organ dose directly in the field and therefore dose conversion coefficients (DCC) are needed to convert measurable values such as air kerma to organ dose. Previous work on these coefficients has been conducted mainly for adults with a focus on radiation protection workers. Hence, there is a large gap in the literature for pediatric values. This study coupled a Monte Carlo N-Particle eXtended (MCNPX) code with International Council of Radiological Protection (ICRP)-adopted University of Florida and National Cancer Institute pediatric reference phantoms to calculate a comprehensive list of dose conversion coefficients (mGy/mGy) to convert air-kerma to organ dose. Parameters included ten phantoms (newborn, 1-year, 5-year, 10-year, 15-year old male and female), 28 organs over 33 energies between 0.01 and 20 MeV in six (6) irradiation geometries relevant to a child who might be exposed to a radiological release: anterior-posterior (AP), posterior-anterior (PA), right-lateral (RLAT), left-lateral (LLAT), rotational (ROT), and isotropic (ISO). Dose conversion coefficients to the red bone marrow over 36 skeletal sites were also calculated. It was hypothesized that the pediatric organ dose conversion coefficients would follow similar trends to the published adult values as dictated by human anatomy, but be of a higher magnitude. It was found that while the pediatric coefficients did yield similar patterns to that of the adult coefficients, depending on the organ and irradiation geometry, the pediatric values could be lower or higher than that of the adult coefficients.

  18. Hybrid computational phantoms of the male and female newborn patient: NURBS-based whole-body models

    NASA Astrophysics Data System (ADS)

    Lee, Choonsik; Lodwick, Daniel; Hasenauer, Deanna; Williams, Jonathan L.; Lee, Choonik; Bolch, Wesley E.

    2007-07-01

    Anthropomorphic computational phantoms are computer models of the human body for use in the evaluation of dose distributions resulting from either internal or external radiation sources. Currently, two classes of computational phantoms have been developed and widely utilized for organ dose assessment: (1) stylized phantoms and (2) voxel phantoms which describe the human anatomy via mathematical surface equations or 3D voxel matrices, respectively. Although stylized phantoms based on mathematical equations can be very flexible in regard to making changes in organ position and geometrical shape, they are limited in their ability to fully capture the anatomic complexities of human internal anatomy. In turn, voxel phantoms have been developed through image-based segmentation and correspondingly provide much better anatomical realism in comparison to simpler stylized phantoms. However, they themselves are limited in defining organs presented in low contrast within either magnetic resonance or computed tomography images—the two major sources in voxel phantom construction. By definition, voxel phantoms are typically constructed via segmentation of transaxial images, and thus while fine anatomic features are seen in this viewing plane, slice-to-slice discontinuities become apparent in viewing the anatomy of voxel phantoms in the sagittal or coronal planes. This study introduces the concept of a hybrid computational newborn phantom that takes full advantage of the best features of both its stylized and voxel counterparts: flexibility in phantom alterations and anatomic realism. Non-uniform rational B-spline (NURBS) surfaces, a mathematical modeling tool traditionally applied to graphical animation studies, was adopted to replace the limited mathematical surface equations of stylized phantoms. A previously developed whole-body voxel phantom of the newborn female was utilized as a realistic anatomical framework for hybrid phantom construction. The construction of a hybrid

  19. Hesperetin induces melanin production in adult human epidermal melanocytes.

    PubMed

    Usach, Iris; Taléns-Visconti, Raquel; Magraner-Pardo, Lorena; Peris, José-Esteban

    2015-06-01

    One of the major sources of flavonoids for humans are citrus fruits, hesperidin being the predominant flavonoid. Hesperetin (HSP), the aglycon of hesperidin, has been reported to provide health benefits such as antioxidant, anti-inflammatory and anticarcinogenic effects. However, the effect of HSP on skin pigmentation is not clear. Some authors have found that HSP induces melanogenesis in murine B16-F10 melanoma cells, which, if extrapolated to in vivo conditions, might protect skin against photodamage. Since the effect of HSP on normal melanocytes could be different to that observed on melanoma cells, the described effect of HSP on murine melanoma cells has been compared to the effect obtained using normal human melanocytes. HSP concentrations of 25 and 50 µM induced melanin synthesis and tyrosinase activity in human melanocytes in a concentration-dependent manner. Compared to control melanocytes, 25 µM HSP increased melanin production and tyrosinase activity 1.4-fold (p < 0.01) and 1.1-fold (p < 0.01), respectively, and the corresponding increases in the case of 50 µM HSP were 1.9-fold (p < 0.001) and 1.3-fold (p < 0.001). Therefore, HSP could be considered a valuable photoprotective substance if its capacity to increase melanin production in human melanocyte cultures could be reproduced on human skin.

  20. The landscape of genomic imprinting across diverse adult human tissues

    PubMed Central

    Baran, Yael; Subramaniam, Meena; Biton, Anne; Tukiainen, Taru; Tsang, Emily K.; Rivas, Manuel A.; Pirinen, Matti; Gutierrez-Arcelus, Maria; Smith, Kevin S.; Kukurba, Kim R.; Zhang, Rui; Eng, Celeste; Torgerson, Dara G.; Urbanek, Cydney; Li, Jin Billy; Rodriguez-Santana, Jose R.; Burchard, Esteban G.; Seibold, Max A.; MacArthur, Daniel G.; Montgomery, Stephen B.; Zaitlen, Noah A.; Lappalainen, Tuuli

    2015-01-01

    Genomic imprinting is an important regulatory mechanism that silences one of the parental copies of a gene. To systematically characterize this phenomenon, we analyze tissue specificity of imprinting from allelic expression data in 1582 primary tissue samples from 178 individuals from the Genotype-Tissue Expression (GTEx) project. We characterize imprinting in 42 genes, including both novel and previously identified genes. Tissue specificity of imprinting is widespread, and gender-specific effects are revealed in a small number of genes in muscle with stronger imprinting in males. IGF2 shows maternal expression in the brain instead of the canonical paternal expression elsewhere. Imprinting appears to have only a subtle impact on tissue-specific expression levels, with genes lacking a systematic expression difference between tissues with imprinted and biallelic expression. In summary, our systematic characterization of imprinting in adult tissues highlights variation in imprinting between genes, individuals, and tissues. PMID:25953952

  1. Development and clinical application of a length-adjustable water phantom for total body irradiation.

    PubMed

    Chen, Zhi-Wei; Yao, Sheng-Yu; Zhang, Tie-Ning; Zhu, Zhen-Hua; Hu, Zhe-Kai; Lu, Xun

    2012-08-01

    A new type of water phantom which would be specialised for the absorbed dose measurement in total body irradiation (TBI) treatment is developed. Ten millimetres of thick Plexiglas plates were arranged to form a square cube with 300 mm of edge length. An appropriate sleeve-type piston was installed on the side wall, and a tabular Plexiglas piston was positioned inside the sleeve. By pushing and pulling the piston, the length of the self-made water phantom could be varied to meet the required patients' physical sizes. To compare the international standard water phantom with the length-adjustable and the Plexiglas phantoms, absorbed dose for 6-MV X ray was measured by an ionisation chamber at different depths in three kinds of phantoms. In 70 cases with TBI, midplane doses were metered using the length-adjustable and the Plexiglas phantoms for simulating human dimensions, and dose validation was synchronously carried out. There were no significant statistical differences, p > 0.05, through statistical processing of data from the international standard water phantom and the self-designed one. There were significant statistical differences, p < 0.05, between the two sets of data from the standard and the Plexiglas one. In addition, the absolute difference had a positive correlation with the varied depth of the detector in the Plexiglas phantom. Comparing the data of clinical treatment, the differences were all <1 % among the prescription doses and the validation data collected from the self-design water phantom. However, the differences collected from the Plexiglas phantom were increasing gradually from +0.77 to +2.30 % along with increasing body width. Obviously, the difference had a positive correlation with the body width. The results proved that the new length-adjustable water phantom is more accurate for simulating human dimensions than Plexiglas phantom.

  2. An anatomically realistic brain phantom for quantification with positron tomography

    SciTech Connect

    Wong, D.F.; Links, J.M.; Molliver, M.E.; Hengst, T.C.; Clifford, C.M.; Buhle, L.; Bryan, M.; Stumpf, M.; Wagner, H.N. Jr.

    1984-01-01

    Phantom studies are useful in assessing and maximizing the accuracy and precision of quantification of absolute activity, assessing errors associated with patient positioning, and dosimetry. Most phantoms are limited by the use of simple shapes, which do not adequately reflect real anatomy. The authors have constructed an anatomically realistic life-size brain phantom for positron tomography studies. The phantom consists of separately fillable R + L caudates, R + L putamens, R + L globus passidus and cerebellum. These structures are contained in proper anatomic orientation within a fillable cerebrum. Solid ventricles are also present. The entire clear vinyl cerebrum is placed in a human skull. The internal brain structures were fabricated from polyester resin, with dimensions, shapes and sizes of the structures obtained from digitized contours of brain slices in the U.C.S.D. computerized brain atlas. The structures were filled with known concentrations of Ga-68 in water and scanned with our NeuroECAT. The phantom was aligned in the scanner for each structure, such that the tomographic slice passed through that structure's center. After calibration of the scanner with a standard phantom for counts/pixel uCi/cc conversion, the measured activity concentrations were compared with the actual concentrations. The ratio of measured to actual activity concentration (''recovery coefficient'') for the caudate was 0.33; for the putamen 0.42. For comparison, the ratio for spheres of diameters 9.5, 16,19 and 25.4 mm was 0.23, 0.54, 0.81, and 0.93. This phantom provides more realistic assessment of performance and allows calculation of correction factors.

  3. 21 CFR 892.1950 - Radiographic anthropomorphic phantom.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Radiographic anthropomorphic phantom. 892.1950 Section 892.1950 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1950 Radiographic...

  4. 21 CFR 892.1950 - Radiographic anthropomorphic phantom.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Radiographic anthropomorphic phantom. 892.1950 Section 892.1950 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1950 Radiographic...

  5. Testosterone affects language areas of the adult human brain

    PubMed Central

    Hahn, Andreas; Kranz, Georg S.; Sladky, Ronald; Kaufmann, Ulrike; Ganger, Sebastian; Hummer, Allan; Seiger, Rene; Spies, Marie; Vanicek, Thomas; Winkler, Dietmar; Kasper, Siegfried; Windischberger, Christian; Swaab, Dick F.

    2016-01-01

    Abstract Although the sex steroid hormone testosterone is integrally involved in the development of language processing, ethical considerations mostly limit investigations to single hormone administrations. To circumvent this issue we assessed the influence of continuous high‐dose hormone application in adult female‐to‐male transsexuals. Subjects underwent magnetic resonance imaging before and after 4 weeks of testosterone treatment, with each scan including structural, diffusion weighted and functional imaging. Voxel‐based morphometry analysis showed decreased gray matter volume with increasing levels of bioavailable testosterone exclusively in Broca's and Wernicke's areas. Particularly, this may link known sex differences in language performance to the influence of testosterone on relevant brain regions. Using probabilistic tractography, we further observed that longitudinal changes in testosterone negatively predicted changes in mean diffusivity of the corresponding structural connection passing through the extreme capsule. Considering a related increase in myelin staining in rodents, this potentially reflects a strengthening of the fiber tract particularly involved in language comprehension. Finally, functional images at resting‐state were evaluated, showing increased functional connectivity between the two brain regions with increasing testosterone levels. These findings suggest testosterone‐dependent neuroplastic adaptations in adulthood within language‐specific brain regions and connections. Importantly, deteriorations in gray matter volume seem to be compensated by enhancement of corresponding structural and functional connectivity. Hum Brain Mapp 37:1738–1748, 2016. © 2016 Wiley Periodicals, Inc. PMID:26876303

  6. Dose distributions in a human head phantom for neutron capture therapy using moderated neutrons from the 2.5 MeV proton-7Li reaction or from fission of 235U

    NASA Astrophysics Data System (ADS)

    Tanaka, Kenichi; Kobayashi, Tooru; Sakurai, Yoshinori; Nakagawa, Yoshinobu; Endo, Satoru; Hoshi, Masaharu

    2001-10-01

    The feasibility of neutron capture therapy (NCT) using an accelerator-based neutron source of the 7Li(p,n) reaction produced by 2.5 MeV protons was investigated by comparing the neutron beam tailored by both the Hiroshima University radiological research accelerator (HIRRAC) and the heavy water neutron irradiation facility in the Kyoto University reactor (KUR-HWNIF) from the viewpoint of the contamination dose ratios of the fast neutrons and the gamma rays. These contamination ratios to the boron dose were estimated in a water phantom of 20 cm diameter and 20 cm length to simulate a human head, with experiments by the same techniques for NCT in KUR-HWNIF and/or the simulation calculations by the Monte Carlo N-particle transport code system version 4B (MCNP-4B). It was found that the 7Li(p,n) neutrons produced by 2.5 MeV protons combined with 20, 25 or 30 cm thick D2O moderators of 20 cm diameter could make irradiation fields for NCT with depth-dose characteristics similar to those from the epithermal neutron beam at the KUR-HWNIF.

  7. Effect of Anatomical Modeling on Space Radiation Dose Estimates: A Comparison of Doses for NASA Phantoms and 5th, 50th, and 95th Percentile UF Hybrid Phantoms

    NASA Technical Reports Server (NTRS)

    Bahadori, A.; VanBaalen, M.; Shavers, M.; Semones, E.; Dodge, C.; Bolch, W.

    2010-01-01

    The estimate of absorbed dose to individual organs of a space crewmember is affected by the geometry of the anatomical model of the astronaut used in the radiation transport calculation. For astronaut dosimetry, NASA currently uses the computerized anatomical male (CAM) and computerized anatomical female (CAF) stylized phantoms to represent astronauts in its operational radiation dose analyses. These phantoms are available in one size and in two body positions. In contrast, the UF Hybrid Adult Male and Female (UFHADM and UFHADF) phantoms have organ shapes based on actual CT data. The surfaces of these phantoms are defined by non-uniform rational B-spline surfaces, and are thus flexible in terms of body morphometry and extremity positioning. In this study, UFHADM and UFHADF are scaled to dimensions corresponding to 5th, 50th, and 95th percentile (PCTL) male and female astronauts. A ray-tracing program is written in Visual Basic 2008, which is then used to create areal density maps for dose points corresponding to various organs within the phantoms. The areal density maps, along with appropriate space radiation spectra, are input into the NASA program couplet HZETRN/BRYNTRN, and organ doses are calculated. The areal density maps selected tissues and organs of the 5th, 50th, and 95th PCTL male and female phantoms are presented and compared. In addition, the organ doses for the 5th, 50th, and 95th PCTL male and female phantoms are presented and compared to organ doses for CAM and CAF.

  8. Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome in Older Adults.

    PubMed

    Scott, Jake; Goetz, Matthew Bidwell

    2016-08-01

    Improved survival with combination antiretroviral therapy has led to a dramatic increase in the number of human immunodeficiency virus (HIV)-infected individuals 50 years of age or older such that by 2020 more than 50% of HIV-infected persons in the United States will be above this age. Recent studies confirm that antiretroviral therapy should be offered to all HIV-infected patients regardless of age, symptoms, CD4+ cell count, or HIV viral load. However, when compared with HIV-uninfected populations, even with suppression of measurable HIV replication, older individuals are at greater risk for cardiovascular disease, malignancies, liver disease, and other comorbidities.

  9. Adult human adipose tissue contains several types of multipotent cells.

    PubMed

    Tallone, Tiziano; Realini, Claudio; Böhmler, Andreas; Kornfeld, Christopher; Vassalli, Giuseppe; Moccetti, Tiziano; Bardelli, Silvana; Soldati, Gianni

    2011-04-01

    Multipotent mesenchymal stromal cells (MSCs) are a type of adult stem cells that can be easily isolated from various tissues and expanded in vitro. Many reports on their pluripotency and possible clinical applications have raised hopes and interest in MSCs. In an attempt to unify the terminology and the criteria to label a cell as MSC, in 2006 the International Society for Cellular Therapy (ISCT) proposed a standard set of rules to define the identity of these cells. However, MSCs are still extracted from different tissues, by diverse isolation protocols, are cultured and expanded in different media and conditions. All these variables may have profound effects on the selection of cell types and the composition of heterogeneous subpopulations, on the selective expansion of specific cell populations with totally different potentials and ergo, on the long-term fate of the cells upon in vitro culture. Therefore, specific molecular and cellular markers that identify MSCs subsets as well as standardization of expansion protocols for these cells are urgently needed. Here, we briefly discuss new useful markers and recent data supporting the rapidly emerging concept that many different types of progenitor cells are found in close association with blood vessels. This knowledge may promote the necessary technical improvements required to reduce variability and promote higher efficacy and safety when isolating and expanding these cells for therapeutic use. In the light of the discussed data, particularly the identification of new markers, and advances in the understanding of fundamental MSC biology, we also suggest a revision of the 2006 ISCT criteria.

  10. Human germ cell differentiation from fetal- and adult-derived induced pluripotent stem cells

    PubMed Central

    Panula, Sarita; Medrano, Jose V.; Kee, Kehkooi; Bergström, Rosita; Nguyen, Ha Nam; Byers, Blake; Wilson, Kitchener D.; Wu, Joseph C.; Simon, Carlos; Hovatta, Outi; Reijo Pera, Renee A.

    2011-01-01

    Historically, our understanding of molecular genetic aspects of human germ cell development has been limited, at least in part due to inaccessibility of early stages of human development to experimentation. However, the derivation of pluripotent stem cells may provide the necessary human genetic system to study germ cell development. In this study, we compared the potential of human induced pluripotent stem cells (iPSCs), derived from adult and fetal somatic cells to form primordial and meiotic germ cells, relative to human embryonic stem cells. We found that ∼5% of human iPSCs differentiated to primordial germ cells (PGCs) following induction with bone morphogenetic proteins. Furthermore, we observed that PGCs expressed green fluorescent protein from a germ cell-specific reporter and were enriched for the expression of endogenous germ cell-specific proteins and mRNAs. In response to the overexpression of intrinsic regulators, we also observed that iPSCs formed meiotic cells with extensive synaptonemal complexes and post-meiotic haploid cells with a similar pattern of ACROSIN staining as observed in human spermatids. These results indicate that human iPSCs derived from reprogramming of adult somatic cells can form germline cells. This system may provide a useful model for molecular genetic studies of human germline formation and pathology and a novel platform for clinical studies and potential therapeutical applications. PMID:21131292

  11. Treatment of Human-Caused Trauma: Attrition in the Adult Outcomes Research

    ERIC Educational Resources Information Center

    Matthieu, Monica; Ivanoff, Andre

    2006-01-01

    Attrition or dropout is the failure of a participant to complete, comply, or the prematurely discontinuation or discharge from treatment, resulting in lost data and affecting outcomes. This review of 10 years of adult posttraumatic stress disorder (PTSD) treatment outcome literature specific to Criterion A events of human origin examines how…

  12. Adult attachment style is associated with cerebral μ-opioid receptor availability in humans.

    PubMed

    Nummenmaa, Lauri; Manninen, Sandra; Tuominen, Lauri; Hirvonen, Jussi; Kalliokoski, Kari K; Nuutila, Pirjo; Jääskeläinen, Iiro P; Hari, Riitta; Dunbar, Robin I M; Sams, Mikko

    2015-09-01

    Human attachment behavior mediates establishment and maintenance of social relationships. Adult attachment characteristically varies on anxiety and avoidance dimensions, reflecting the tendencies to worry about the partner breaking the social bond (anxiety) and feeling uncomfortable about depending on others (avoidance). In primates and other mammals, the endogenous μ-opioid system is linked to long-term social bonding, but evidence of its role in human adult attachment remains more limited. We used in vivo positron emission tomography to reveal how variability in μ-opioid receptor (MOR) availability is associated with adult attachment in humans. We scanned 49 healthy subjects using a MOR-specific ligand [(11) C]carfentanil and measured their attachment avoidance and anxiety with the Experiences in Close Relationships-Revised scale. The avoidance dimension of attachment correlated negatively with MOR availability in the thalamus and anterior cingulate cortex, as well as the frontal cortex, amygdala, and insula. No associations were observed between MOR availability and the anxiety dimension of attachment. Our results suggest that the endogenous opioid system may underlie interindividual differences in avoidant attachment style in human adults, and that differences in MOR availability are associated with the individuals' social relationships and psychosocial well-being. PMID:26046928

  13. Perspectives on Adult Education, Human Resource Development, and the Emergence of Workforce Development

    ERIC Educational Resources Information Center

    Jacobs, Ronald L.

    2014-01-01

    This article presents a perspective on the relationship between adult education and human resource development of the past two decades and the subsequent emergence of workforce development. The lesson taken from the article should be more than simply a recounting of events related to these fields of study. Instead, the more general lesson may be…

  14. Concept Maps: Practice Applications in Adult Education and Human Resource Development

    ERIC Educational Resources Information Center

    Daley, Barbara J.

    2010-01-01

    Concept maps can be used as both a cognitive and constructivist learning strategy in teaching and learning in adult education and human resource development. The maps can be used to understand course readings, analyze case studies, develop reflective thinking and enhance research skills. The creation of concept maps can also be supported by the…

  15. Emotions and Human Concern: Adult Education and the Philosophical Thought of Martha Nussbaum

    ERIC Educational Resources Information Center

    Plumb, Donovan

    2014-01-01

    This article argues that philosopher Martha Nussbaum's reflections on the role of the emotions in human flourishing can contribute in important ways to our understanding of the emotions in adult education contexts. The article summarises Nussbaum's exploration of the contributions of classical philosophers like Socrates, Aristotle, and…

  16. Evaluation of Serum Creatinine Changes With Integrase Inhibitor Use in Human Immunodeficiency Virus-1 Infected Adults

    PubMed Central

    Lindeman, Tara A.; Duggan, Joan M.; Sahloff, Eric G.

    2016-01-01

    This retrospective chart review evaluated changes in serum creatinine and creatinine clearance (CrCl) after initiation of an integrase inhibitor (INSTI)-based regimen as initial treatment in human immunodeficiency virus-infected adults. Serum creatinine and CrCl changes were similar to those seen in clinical trials for INSTIs. No renal-related serious adverse events or discontinuations occurred. PMID:27092314

  17. NIRS Measurement of Venous Oxygen Saturation in the Adult Human Head

    NASA Astrophysics Data System (ADS)

    Brown, Derek W.; Haensse, Daniel; Bauschatz, Andrea; Wolf, Martin

    Provided that both the breathing frequency remains constant and that the temporal resolution of the instrument is sufficiently high, NIRS spiroximetry enables measurement of cerebral SvO2 in healthy human adults. Furthermore, simultaneous measurements of StO2, SaO2, and SvO2 enable calculation of both OEF and the compartmental distribution of cerebral blood volume.

  18. Equality and Human Capital: Conflicting Concepts within State-Funded Adult Education in Ireland

    ERIC Educational Resources Information Center

    Hurley, Kevin

    2015-01-01

    This article offers a critique of the concept of equality as it informs the White Paper on Adult Education: Learning for Life (2000). It also outlines the extent to which human capital theory can be seen to have effectively colonised lifelong learning from the outset of its adoption by the European Union with highly constraining implications for…

  19. Severe Infections with Human Adenovirus 7d in 2 Adults in Family, Illinois, USA, 2014

    PubMed Central

    Ison, Michael G.

    2016-01-01

    Human adenovirus 7d, a genomic variant with no reported circulation in the United States, was isolated from 2 adults with severe respiratory infections in Illinois. Molecular typing identified a close relationship with strains of the same genome type isolated from cases of respiratory disease in several provinces of China since 2009. PMID:26982199

  20. Bridging the Gap between Human Resource Development and Adult Education: Part One, Assumptions, Definitions, and Critiques

    ERIC Educational Resources Information Center

    Hatcher, Tim; Bowles, Tuere

    2006-01-01

    Human resource development (HRD) as a scholarly endeavor and as a practice is often criticized in the adult education (AE) literature and by AE scholars as manipulative and oppressive and, through training and other interventions, controlling workers for strictly economic ends (Baptiste, 2001; Cunningham, 2004; Schied, 2001; Welton, 1995).…

  1. Bridging the Gap between Human Resource Development and Adult Education: Part Two, the Critical Turn

    ERIC Educational Resources Information Center

    Hatcher, Tim; Bowles, Tuere

    2006-01-01

    Human resource development (HRD) as a scholarly endeavor and as a practice is often criticized in the adult education (AE) literature and by AE scholars as manipulative and oppressive and, through training and other interventions, controlling workers for strictly economic ends (Baptiste, 2001; Cunningham, 2004; Schied, 2001; Welton, 1995). The…

  2. An Assessemnt of Graduate Adult Education and Human Resource Development Programs: A U.S. Perspective

    ERIC Educational Resources Information Center

    Akdere, Mesut; Conceicao, Simone C. O.

    2009-01-01

    Due to recent changes in the workplace, the workforce and higher education have driven academic programs of adult education (AE) and human resource development (HRD) in the U.S. to become more integrated as part of the mission of institutions of higher education. In this exploratory study, existing graduate programs in AE and HRD in the U.S. were…

  3. Bridging the Gap between Human Resource Development and Adult Education: Part Two, the Critical Turn

    ERIC Educational Resources Information Center

    Hatcher, Tim; Bowles, Tuere

    2014-01-01

    Human resource development (HRD) as a scholarly endeavor and as a practice is often criticized in the adult education (AE) literature and by AE scholars as manipulative and oppressive and, through training and other interventions, controlling workers for strictly economic ends (Baptiste, 2001; Cunningham, 2004; Schied, 2001; Welton, 1995). The…

  4. Bridging the Gap between Human Resource Development and Adult Education: Part One, Assumptions, Definitions, and Critiques

    ERIC Educational Resources Information Center

    Hatcher, Tim; Bowles, Tuere

    2013-01-01

    Human resource development (HRD) as a scholarly endeavor and as a practice is often criticized in the adult education (AE) literature and by AE scholars as manipulative and oppressive and, through training and other interventions, controlling workers for strictly economic ends (Baptiste, 2001; Cunningham, 2004; Schied, 2001; Welton, 1995).…

  5. 40 CFR 26.1704 - Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults conducted before April 7, 2006. 26.1704 Section 26... Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults conducted...

  6. 40 CFR 26.1705 - Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 1 2011-07-01 2011-07-01 false Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults conducted after April 7, 2006. 26.1705 Section 26... Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults conducted...

  7. 40 CFR 26.1705 - Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 1 2013-07-01 2013-07-01 false Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults initiated after April 7, 2006. 26.1705 Section 26... Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults initiated...

  8. 40 CFR 26.1705 - Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 1 2014-07-01 2014-07-01 false Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults initiated after April 7, 2006. 26.1705 Section 26... Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults initiated...

  9. 40 CFR 26.1704 - Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 1 2012-07-01 2012-07-01 false Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults conducted before April 7, 2006. 26.1704 Section 26... Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults conducted...

  10. 40 CFR 26.1704 - Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 1 2011-07-01 2011-07-01 false Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults conducted before April 7, 2006. 26.1704 Section 26... Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults conducted...

  11. 40 CFR 26.1705 - Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 1 2012-07-01 2012-07-01 false Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults conducted after April 7, 2006. 26.1705 Section 26... Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults conducted...

  12. 40 CFR 26.1705 - Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults conducted after April 7, 2006. 26.1705 Section 26... Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults conducted...

  13. Self-Control and Impulsiveness in Nondieting Adult Human Females: Effects of Visual Food Cues and Food Deprivation

    ERIC Educational Resources Information Center

    Forzano, Lori-Ann B.; Chelonis, John J.; Casey, Caitlin; Forward, Marion; Stachowiak, Jacqueline A.; Wood, Jennifer

    2010-01-01

    Self-control can be defined as the choice of a larger, more delayed reinforcer over a smaller, less delayed reinforcer, and impulsiveness as the opposite. Previous research suggests that exposure to visual food cues affects adult humans' self-control. Previous research also suggests that food deprivation decreases adult humans' self-control. The…

  14. Predictions of ozone absorption in human lungs from newborn to adult

    SciTech Connect

    Overton, J.H.; Graham, R.C.

    1989-01-01

    Dosimetry models for gases mainly have been used to predict absorption in adult humans and laboratory animals. The lack of lower respiratory tract (LRT) lung models for children has discouraged the application of theoretical gaseous dosimetry to this important sub-population. To fill this gap the authors have used several sources of data on age dependent LRT volumes, age dependent airway dimensions, a model of an adult tracheobronchial region, and a model of the adult acinus to construct theoretical LRT lung models for humans from birth to adult. An ozone (O{sub 3}) dosimetry model was then used to estimate the regional and local uptake of O{sub 3} in the (theoretical) LRTs of children and adults. For sedentary breathing, the LRT distribution of absorbed O{sub 3}, the percent uptake (76 to 85%), and the centriacinar O{sub 3} tissue dose are not very sensitive to age. For maximal work during exercise, predicted uptakes range from 83 to 91%, and the regional percent uptakes are more dependent on age than during quiet breathing. In general, total O{sub 3} absorption per minute increases with age. Regardless of age and state of breathing, the largest tissue dose of O{sub 3} is predicted to occur in the centriacinar region, where many animal studies show the maximal morphological damage due to O{sub 3}.

  15. Larval food quantity affects the capacity of adult mosquitoes to transmit human malaria

    PubMed Central

    Shapiro, Lillian L. M.; Murdock, Courtney C.; Jacobs, Gregory R.; Thomas, Rachel J.; Thomas, Matthew B.

    2016-01-01

    Adult traits of holometabolous insects are shaped by conditions experienced during larval development, which might impact interactions between adult insect hosts and parasites. However, the ecology of larval insects that vector disease remains poorly understood. Here, we used Anopheles stephensi mosquitoes and the human malaria parasite Plasmodium falciparum, to investigate whether larval conditions affect the capacity of adult mosquitoes to transmit malaria. We reared larvae in two groups; one group received a standard laboratory rearing diet, whereas the other received a reduced diet. Emerging adult females were then provided an infectious blood meal. We assessed mosquito longevity, parasite development rate and prevalence of infectious mosquitoes over time. Reduced larval food led to increased adult mortality and caused a delay in parasite development and a slowing in the rate at which parasites invaded the mosquito salivary glands, extending the time it took for mosquitoes to become infectious. Together, these effects increased transmission potential of mosquitoes in the high food regime by 260–330%. Such effects have not, to our knowledge, been shown previously for human malaria and highlight the importance of improving knowledge of larval ecology to better understand vector-borne disease transmission dynamics. PMID:27412284

  16. The mechanical properties of human ribs in young adult.

    PubMed

    Pezowicz, Celina; Głowacki, Maciej

    2012-01-01

    A good understanding of thoracic biomechanics is important for complete examination and control of chest behaviour under conditions of physiological and pathological work, and under the impact of external forces leading to traumatic loading of the chest. The purpose of the study was to analyse the mechanical properties of human ribs obtained from individuals under the age of 25 with scoliosis deformation and to correlate them with geometric properties of ribs. Thirty three fragments of ribs (9th to 12th) were tested in three-point bending. Rib fragments were collected intraoperatively from female patients treated for scoliosis in the thoracic, thoracolumbar, and lumbar spine. The results were used to determine the maximum failure force, stiffness, and Young's modulus. A significant relationship was found between the age and elastic modulus of the ribs. The analysis was carried out for two age groups, i.e., between the ages of 10 and 15 and between the ages of 16 and 22, and statistically significant differences were obtained for Young's modulus (p = 0.0001) amounting to, respectively, 2.79 ± 1.34 GPa for the first group and 7.44 ± 2.85 GPa for the second group. The results show a significant impact of age on the mechanical properties of ribs.

  17. A humanized version of Foxp2 does not affect ultrasonic vocalization in adult mice.

    PubMed

    Hammerschmidt, K; Schreiweis, C; Minge, C; Pääbo, S; Fischer, J; Enard, W

    2015-11-01

    The transcription factor FOXP2 has been linked to severe speech and language impairments in humans. An analysis of the evolution of the FOXP2 gene has identified two amino acid substitutions that became fixed after the split of the human and chimpanzee lineages. Studying the functional consequences of these two substitutions in the endogenous Foxp2 gene of mice showed alterations in dopamine levels, striatal synaptic plasticity, neuronal morphology and cortico-striatal-dependent learning. In addition, ultrasonic vocalizations (USVs) of pups had a significantly lower average pitch than control littermates. To which degree adult USVs would be affected in mice carrying the 'humanized' Foxp2 variant remained unclear. In this study, we analyzed USVs of 68 adult male mice uttered during repeated courtship encounters with different females. Mice carrying the Foxp2(hum/hum) allele did not differ significantly in the number of call elements, their element structure or in their element composition from control littermates. We conclude that neither the structure nor the usage of USVs in adult mice is affected by the two amino acid substitutions that occurred in FOXP2 during human evolution. The reported effect for pup vocalization thus appears to be transient. These results are in line with accumulating evidence that mouse USVs are hardly influenced by vocal learning. Hence, the function and evolution of genes that are necessary, but not sufficient for vocal learning in humans, must be either studied at a different phenotypic level in mice or in other organisms.

  18. Mathematical phantoms for use in reassessment of radiation doses to Japanese atomic-bomb survivors

    SciTech Connect

    Cristy, M.

    1985-07-01

    In 1972 committees of the United Nations and the US National Academy of Sciencs emphasized the need for organ dose estimates on the Japanese atomic-bomb survivors. These estimates were then supplied by workers in Japan and the US, and they were used with the so-called T65D estimates of a survivor's radiation exposure to assess risk from radiation. Recently the T65D estimates have been questioned, and programs for reassessment of atomic-bomb radiation dosimetry have been started in Japan and the US. As a part of this new effort a mathematical analogue of the human body (or ''mathematical phantom''), to be used in estimating organ doses in adult survivors, is presented here. Recommendations on organ dosimetry for juvenile survivors are also presented and discussed. 57 refs., 10 figs., 6 tabs.

  19. Predictions of ozone absorption in human lungs from newborn to adult

    SciTech Connect

    Overton, J.H.; Graham, R.C. )

    1989-01-01

    Although children are an important human population, dosimetry models for gases have been used to predict absorption mainly in laboratory animals and adult humans. To correct this omission, we have used several sources of data on age-dependent lower respiratory tract (LRT) volumes, age-dependent airway dimensions, a model of the adult tracheobronchial region, and a model of the adult acinus to construct theoretical LRT lung models for humans from birth to adulthood. An ozone (O3) dosimetry model was then used to estimate the regional and local uptake of O3 in the (theoretical) LRT of children and adults. For sedentary or quiet breathing, the LRT distribution of absorbed O3, the percent uptake (84 to 88%) and the centriacinar O3 tissue dose are not very sensitive to age. For maximal work during exercise, predicted LRT uptakes range from 87 to 93%, and the regional percent uptakes are more dependent on age than during quiet breathing. In general, the total quantity of O3 absorbed per minute increases with age. Regardless of age and state of breathing, the largest tissue dose of O3 is predicted to occur in the centriacinar region, where many animal studies show the maximal morphological damage from O3.

  20. Localization of PPAR isotypes in the adult mouse and human brain

    PubMed Central

    Warden, Anna; Truitt, Jay; Merriman, Morgan; Ponomareva, Olga; Jameson, Kelly; Ferguson, Laura B.; Mayfield, R. Dayne; Harris, R. Adron

    2016-01-01

    Peroxisome proliferator-activated receptors (PPARs) are nuclear hormone receptors that act as ligand-activated transcription factors. PPAR agonists have well-documented anti-inflammatory and neuroprotective roles in the central nervous system. Recent evidence suggests that PPAR agonists are attractive therapeutic agents for treating neurodegenerative diseases as well as addiction. However, the distribution of PPAR mRNA and protein in brain regions associated with these conditions (i.e. prefrontal cortex, nucleus accumbens, amygdala, ventral tegmental area) is not well defined. Moreover, the cell type specificity of PPARs in mouse and human brain tissue has yet to be investigated. We utilized quantitative PCR and double immunofluorescence microscopy to determine that both PPAR mRNA and protein are expressed ubiquitously throughout the adult mouse brain. We found that PPARs have unique cell type specificities that are consistent between species. PPARα was the only isotype to colocalize with all cell types in both adult mouse and adult human brain tissue. Overall, we observed a strong neuronal signature, which raises the possibility that PPAR agonists may be targeting neurons rather than glia to produce neuroprotection. Our results fill critical gaps in PPAR distribution and define novel cell type specificity profiles in the adult mouse and human brain. PMID:27283430

  1. The response of the anterior striatum during adult human vocal learning

    PubMed Central

    Leech, Robert; Iverson, Paul; Wise, Richard J. S.

    2014-01-01

    Research on mammals predicts that the anterior striatum is a central component of human motor learning. However, because vocalizations in most mammals are innate, much of the neurobiology of human vocal learning has been inferred from studies on songbirds. Essential for song learning is a pathway, the homolog of mammalian cortical-basal ganglia “loops,” which includes the avian striatum. The present functional magnetic resonance imaging (fMRI) study investigated adult human vocal learning, a skill that persists throughout life, albeit imperfectly given that late-acquired languages are spoken with an accent. Monolingual adult participants were scanned while repeating novel non-native words. After training on the pronunciation of half the words for 1 wk, participants underwent a second scan. During scanning there was no external feedback on performance. Activity declined sharply in left and right anterior striatum, both within and between scanning sessions, and this change was independent of training and performance. This indicates that adult speakers rapidly adapt to the novel articulatory movements, possibly by using motor sequences from their native speech to approximate those required for the novel speech sounds. Improved accuracy correlated only with activity in motor-sensory perisylvian cortex. We propose that future studies on vocal learning, using different behavioral and pharmacological manipulations, will provide insights into adult striatal plasticity and its potential for modification in both educational and clinical contexts. PMID:24805076

  2. Neuroscience of human social interactions and adult attachment style

    PubMed Central

    Vrtička, Pascal; Vuilleumier, Patrik

    2012-01-01

    attachment insecurity and particularly anxiety. Emotion regulation strategies such as reappraisal or suppression of social emotions are also differentially modulated by attachment style. This research does not only help better understand the neural underpinnings of human social behavior, but also provides important insights on psychopathological conditions where attachment dysregulation is likely to play an important (causal) role. PMID:22822396

  3. Imaging CDMAM phantom with tomosynthesis

    NASA Astrophysics Data System (ADS)

    Ren, Baorui; Smith, Andy; Ruth, Chris; Jing, Zhenxue

    2008-03-01

    We studied the use of the mammography contrast detail phantom (CDMAM) with tomosynthesis to evaluate the performance of our system as well as to explore the application of CDMAM in 3D breast imaging. The system was Hologic's 1st generation tomosynthesis machine. CDMAM phantom plus PMMA slabs were imaged at 3 cm, 5 cm, 7 cm, and 9 cm PMMA-equivalent thickness with 11 projections per scan and the scan angle selected from 0, 15 and 28 degrees. CDMAM images were reconstructed using the back projection method, and were scored with the CDCOM automatic analysis program. The threshold thickness of each disk size was obtained with psychometric curve fitting. We first studied errors and variability associated with the results when different numbers of images were used in contrast detail analysis, then studied factors that affected CDMAM results in tomosynthesis, including the x-ray dose, the scan angle, the in-plane reconstruction pixel size, the slice-to-slice step size, the location of the CDMAM inside the PMMA slabs, and the scatter effect. This paper will present results of CDMAM performance of our tomosynthesis system, as well as their dependence on the various factors, and the comparison with 2D mammography. Additionally we will discuss the novel processing and analysis methods developed during this study, and make proposals to modify the CDMAM phantom and the CDCOM analysis program to optimize the method for 3D tomosynthesis.

  4. Human Centred Design Considerations for Connected Health Devices for the Older Adult

    PubMed Central

    Harte, Richard P.; Glynn, Liam G.; Broderick, Barry J.; Rodriguez-Molinero, Alejandro; Baker, Paul M. A.; McGuiness, Bernadette; O’Sullivan, Leonard; Diaz, Marta; Quinlan, Leo R.; ÓLaighin, Gearóid

    2014-01-01

    Connected health devices are generally designed for unsupervised use, by non-healthcare professionals, facilitating independent control of the individuals own healthcare. Older adults are major users of such devices and are a population significantly increasing in size. This group presents challenges due to the wide spectrum of capabilities and attitudes towards technology. The fit between capabilities of the user and demands of the device can be optimised in a process called Human Centred Design. Here we review examples of some connected health devices chosen by random selection, assess older adult known capabilities and attitudes and finally make analytical recommendations for design approaches and design specifications. PMID:25563225

  5. Short-Term Monocular Deprivation Alters GABA in the Adult Human Visual Cortex

    PubMed Central

    Lunghi, Claudia; Emir, Uzay E.; Morrone, Maria Concetta; Bridge, Holly

    2016-01-01

    Summary Neuroplasticity is a fundamental property of the nervous system that is maximal early in life, within the critical period [1–3]. Resting GABAergic inhibition is necessary to trigger ocular dominance plasticity and to modulate the onset and offset of the critical period [4, 5]. GABAergic inhibition also plays a crucial role in neuroplasticity of adult animals: the balance between excitation and inhibition in the primary visual cortex (V1), measured at rest, modulates the susceptibility of ocular dominance to deprivation [6–10]. In adult humans, short-term monocular deprivation strongly modifies ocular balance, unexpectedly boosting the deprived eye, reflecting homeostatic plasticity [11, 12]. There is no direct evidence, however, to support resting GABAergic inhibition in homeostatic plasticity induced by visual deprivation. Here, we tested the hypothesis that GABAergic inhibition, measured at rest, is reduced by deprivation, as demonstrated by animal studies. GABA concentration in V1 of adult humans was measured using ultra-high-field 7T magnetic resonance spectroscopy before and after short-term monocular deprivation. After monocular deprivation, resting GABA concentration decreased in V1 but was unaltered in a control parietal area. Importantly, across participants, the decrease in GABA strongly correlated with the deprived eye perceptual boost measured by binocular rivalry. Furthermore, after deprivation, GABA concentration measured during monocular stimulation correlated with the deprived eye dominance. We suggest that reduction in resting GABAergic inhibition triggers homeostatic plasticity in adult human V1 after a brief period of abnormal visual experience. These results are potentially useful for developing new therapeutic strategies that could exploit the intrinsic residual plasticity of the adult human visual cortex. PMID:26004760

  6. Influence of phantom diameter, kVp and scan mode upon computed tomography dose index.

    PubMed

    Nickoloff, Edward L; Dutta, Ajoy K; Lu, Zheng F

    2003-03-01

    The computed tomography (CT) radiation dose to pediatric patients has received considerable attention recently. Moreover, it is important to be able to determine CT radiation doses for various patient sizes ranging from infants to large adults. The current AAPM protocol only measures CT radiation dose using a 16 cm acrylic phantom to represent an adult head and a 32 cm acrylic phantom to represent an adult body. The goal of this paper is to study the dependence of the computed tomography dose index (CTDI) upon the size of the phantom, the kVp selected and the scan mode employed. Our measurements were done on phantom sizes ranging from 6 cm to 32 cm. The x-ray tube potential ranged from 80 to 140 kVp. The scan modes utilized for the measurements included: consecutive axial scans, single-slice helical scans with variable pitch and multislice helical scans with variable pitch. The results were consolidated into simplified equations which related the phantom diameter and kVp to the measured CTDI. Some generalizations were made about the relationship between the scan modes of the various CT units to the measured radiation doses. The CTDI appears to be an exponential function of phantom diameter. For the same kVp and mAs, the radiation doses for smaller phantoms are much greater than for larger sizes. The derived relationship can be used to estimate the radiation doses for a variety of scan conditions and modes from measurements with the two standard reference phantoms. A method was also given for converting axial CT dose measurements to appropriate MSAD values for helical CT scans.

  7. CB1 cannabinoid receptor enrichment in the ependymal region of the adult human spinal cord.

    PubMed

    Paniagua-Torija, Beatriz; Arevalo-Martin, Angel; Ferrer, Isidro; Molina-Holgado, Eduardo; Garcia-Ovejero, Daniel

    2015-12-04

    Cannabinoids are involved in the regulation of neural stem cell biology and their receptors are expressed in the neurogenic niches of adult rodents. In the spinal cord of rats and mice, neural stem cells can be found in the ependymal region, surrounding the central canal, but there is evidence that this region is largely different in adult humans: lacks a patent canal and presents perivascular pseudorosettes, typically found in low grade ependymomas. Using Laser Capture Microdissection, Taqman gene expression assays and immunohistochemistry, we have studied the expression of endocannabinoid system components (receptors and enzymes) at the human spinal cord ependymal region. We observe that ependymal region is enriched in CB1 cannabinoid receptor, due to high CB1 expression in GFAP+ astrocytic domains. However, in human spinal cord levels that retain central canal patency we found ependymal cells with high CB1 expression, equivalent to the CB1(HIGH) cell subpopulation described in rodents. Our results support the existence of ependymal CB1(HIGH) cells across species, and may encourage further studies on this subpopulation, although only in cases when central canal is patent. In the adult human ependyma, which usually shows central canal absence, CB1 may play a different role by modulating astrocyte functions.

  8. CB1 cannabinoid receptor enrichment in the ependymal region of the adult human spinal cord

    PubMed Central

    Paniagua-Torija, Beatriz; Arevalo-Martin, Angel; Ferrer, Isidro; Molina-Holgado, Eduardo; Garcia-Ovejero, Daniel

    2015-01-01

    Cannabinoids are involved in the regulation of neural stem cell biology and their receptors are expressed in the neurogenic niches of adult rodents. In the spinal cord of rats and mice, neural stem cells can be found in the ependymal region, surrounding the central canal, but there is evidence that this region is largely different in adult humans: lacks a patent canal and presents perivascular pseudorosettes, typically found in low grade ependymomas. Using Laser Capture Microdissection, Taqman gene expression assays and immunohistochemistry, we have studied the expression of endocannabinoid system components (receptors and enzymes) at the human spinal cord ependymal region. We observe that ependymal region is enriched in CB1 cannabinoid receptor, due to high CB1 expression in GFAP+ astrocytic domains. However, in human spinal cord levels that retain central canal patency we found ependymal cells with high CB1 expression, equivalent to the CB1HIGH cell subpopulation described in rodents. Our results support the existence of ependymal CB1HIGH cells across species, and may encourage further studies on this subpopulation, although only in cases when central canal is patent. In the adult human ependyma, which usually shows central canal absence, CB1 may play a different role by modulating astrocyte functions. PMID:26634814

  9. Immunohistochemical Study of Expression of Sohlh1 and Sohlh2 in Normal Adult Human Tissues

    PubMed Central

    Zhang, Xiaoli; Liu, Ruihua; Su, Zhongxue; Zhang, Yuecun; Zhang, Wenfang; Liu, Xinyu; Wang, Fuwu; Guo, Yuji; Li, Chuangang; Hao, Jing

    2015-01-01

    The expression pattern of Sohlh1 (spermatogenesis and oogenesis specific basic helix-loop-helix 1) and Sohlh2 in mice has been reported in previous studies. Sohlh1 and Sohlh2 are specifically expressed in spermatogonia, prespermatogonia in male mice and oocytes of primordial and primary follicles in female mice. In this report, we studied the expression pattern of Sohlh1 and Sohlh2 in human adult tissues. Immunohistochemical staining of Sohlh1 and Sohlh2 was performed in 5 samples of normal ovaries and testes, respectively. The results revealed that Sohlh genes are not only expressed in oocytes and spermatogonia, but also in granular cells, theca cells, Sertoli cells and Leydig cells, and in smooth muscles of blood vessel walls. To further investigate the expression of Sohlh genes in other adult human tissues, we collected representative normal adult tissues developed from three embryonic germ layers. Compared with the expression in mice, Sohlhs exhibited a much more extensive expression pattern in human tissues. Sohlhs were detected in testis, ovary and epithelia developed from embryonic endoderm, ectoderm and tissues developed from embryonic mesoderm. Sohlh signals were found in spermatogonia, Sertoli cells and also Leydig cells in testis, while in ovary, the expression was mainly in oocytes of primordial and primary follicles, granular cells and theca cells of secondary follicles. Compared with Sohlh2, the expression of Sohlh1 was stronger and more extensive. Our study explored the expression of Sohlh genes in human tissues and might provide insights for functional studies of Sohlh genes. PMID:26375665

  10. Psychophysical correlates of phantom limb experience.

    PubMed Central

    Katz, J

    1992-01-01

    Phantom limb phenomena were correlated with psychophysiological measures of peripheral sympathetic nervous system activity measured at the amputation stump and contralateral limb. Amputees were assigned to one of three groups depending on whether they reported phantom limb pain, non-painful phantom limb sensations, or no phantom limb at all. Skin conductance and skin temperature were recorded continuously during two 30 minute sessions while subjects continuously monitored and rated the intensity of any phantom limb sensation or pain they experienced. The results from both sessions showed that mean skin temperature was significantly lower at the stump than the contralateral limb in the groups with phantom limb pain and non-painful phantom limb sensations, but not among subjects with no phantom limb at all. In addition, stump skin conductance responses correlated significantly with the intensity of non-painful phantom limb paresthesiae but not other qualities of sensation or pain. Between-limb measures of pressure sensitivity were not significantly different in any group. The results suggest that the presence of a phantom limb, whether painful or painless, is related to the sympathetic-efferent outflow of cutaneous vasoconstrictor fibres in the stump and stump neuromas. The hypothesis of a sympathetic-efferent somatic-afferent mechanism involving both sudomotor and vasoconstrictor fibres is proposed to explain the relationship between stump skin conductance responses and non-painful phantom limb paresthesiae. It is suggested that increases in the intensity of phantom limb paresthesiae follow bursts of sympathetic activity due to neurotransmitter release onto apposing sprouts of large diameter primary afferents located in stump neuromas, and decreases correspond to periods of relative sympathetic inactivity. The results of the study agree with recent suggestions that phantom limb pain is not a unitary syndrome, but a symptom class with each class subserved by

  11. Development of an anthropomorphic head phantom using dolomite and polymethyl methacrylate for dosimetry in computed tomography

    NASA Astrophysics Data System (ADS)

    Ximenes, R. E.; Silva, A.; Balbino, D.; Poletti, M. E.; Maia, A. F.

    2015-12-01

    A real human skull was selected to be a mold for the construction of an anthropomorphic head phantom with a mixture of dolomite and polymethyl methacrylate (PMMA). Using linear attenuation coefficients, we show that it is possible to use dolomite as a bone simulator as long as the proportion of the mixture is 1:1. Acrylic tubes were placed in the phantom constructed to enable the insertion of the ionization chamber to estimate the effective dose. Values for a typical head computed tomography examination found in the literature vary from 0.9 to 4.0 mSv. Dosimetric studies showed that the effective dose for the anthropomorphic phantom was (2.70±0.03) mSv and for the geometric PMMA phantom (3.67±0.04) mSv, values which are in agreement with the intervals reported in the literature. The investment to produce the phantom was approximately US160.00.

  12. MRI-Derived 3-D-Printed Breast Phantom for Microwave Breast Imaging Validation.

    PubMed

    Burfeindt, Matthew J; Colgan, Timothy J; Mays, R Owen; Shea, Jacob D; Behdad, Nader; Van Veen, Barry D; Hagness, Susan C

    2012-01-01

    We propose a 3-D-printed breast phantom for use in preclinical experimental microwave imaging studies. The phantom is derived from an MRI of a human subject; thus, it is anthropomorphic, and its interior is very similar to an actual distribution of fibroglandular tissues. Adipose tissue in the breast is represented by the solid plastic (printed) regions of the phantom, while fibroglandular tissue is represented by liquid-filled voids in the plastic. The liquid is chosen to provide a biologically relevant dielectric contrast with the printed plastic. Such a phantom enables validation of microwave imaging techniques. We describe the procedure for generating the 3-D-printed breast phantom and present the measured dielectric properties of the 3-D-printed plastic over the frequency range 0.5-3.5 GHz. We also provide an example of a suitable liquid for filling the fibroglandular voids in the plastic.

  13. Origin of germ cells and formation of new primary follicles in adult human ovaries

    PubMed Central

    Bukovsky, Antonin; Caudle, Michael R; Svetlikova, Marta; Upadhyaya, Nirmala B

    2004-01-01

    Recent reports indicate that functional mouse oocytes and sperm can be derived in vitro from somatic cell lines. We hypothesize that in adult human ovaries, mesenchymal cells in the tunica albuginea (TA) are bipotent progenitors with a commitment for both primitive granulosa and germ cells. We investigated ovaries of twelve adult women (mean age 32.8 ± 4.1 SD, range 27–38 years) by single, double, and triple color immunohistochemistry. We show that cytokeratin (CK)+ mesenchymal cells in ovarian TA differentiate into surface epithelium (SE) cells by a mesenchymal-epithelial transition. Segments of SE directly associated with ovarian cortex are overgrown by TA, forming solid epithelial cords, which fragment into small (20 micron) epithelial nests descending into the lower ovarian cortex, before assembling with zona pellucida (ZP)+ oocytes. Germ cells can originate from SE cells which cover the TA. Small (10 micron) germ-like cells showing PS1 meiotically expressed oocyte carbohydrate protein are derived from SE cells via asymmetric division. They show nuclear MAPK immunoexpression, subsequently divide symmetrically, and enter adjacent cortical vessels. During vascular transport, the putative germ cells increase to oocyte size, and are picked-up by epithelial nests associated with the vessels. During follicle formation, extensions of granulosa cells enter the oocyte cytoplasm, forming a single paranuclear CK+ Balbiani body supplying all the mitochondria of the oocyte. In the ovarian medulla, occasional vessels show an accumulation of ZP+ oocytes (25–30 microns) or their remnants, suggesting that some oocytes degenerate. In contrast to males, adult human female gonads do not preserve germline type stem cells. This study expands our previous observations on the formation of germ cells in adult human ovaries. Differentiation of primitive granulosa and germ cells from the bipotent mesenchymal cell precursors of TA in adult human ovaries represents a most

  14. Self-control in adult humans: variation in positive reinforcer amount and delay.

    PubMed Central

    Logue, A W; Peña-Correal, T E; Rodriguez, M L; Kabela, E

    1986-01-01

    In five experiments, choice responding of female human adults was examined, as a function of variations in reinforcer amount and reinforcer delay. Experiment 1 used a discrete-trials procedure, and Experiments 2, 3, 4, and 5 used a concurrent variable-interval variable-interval schedule. Reinforcer amount and reinforcer delay were varied both separately and together. In contrast to results previously reported with pigeons, the subjects in the present experiments usually chose the larger reinforcers even when those reinforcers were delayed. Together, the results from all the experiments suggest that the subjects followed a maximization strategy in choosing reinforcers. Such behavior makes it easy to observe self-control and difficult to observe impulsiveness in traditional laboratory experiments that use adult human subjects. PMID:3760749

  15. Unifying phantom inflation with late-time acceleration: scalar phantom-non-phantom transition model and generalized holographic dark energy

    NASA Astrophysics Data System (ADS)

    Nojiri, Shin'ichi; Odintsov, Sergei D.

    2006-08-01

    The unifying approach to early-time and late-time universe based on phantom cosmology is proposed. We consider gravity-scalar system which contains usual potential and scalar coupling function in front of kinetic term. As a result, the possibility of phantom-non-phantom transition appears in such a way that universe could have effectively phantom equation of state at early time as well as at late time. In fact, the oscillating universe may have several phantom and non-phantom phases. Role in each of two phase and can be absorbed into the redefinition of the scalar field. Right on the transition point, however, the factor cannot be absorbed into the redefinition and play the role to connect two phases smoothly. Holographic dark energy where infrared cutoff is identified with combination of FRW parameters: Hubble constant, particle and future horizons, cosmological constant and universe life-time (if finite). Depending on the specific choice of the model the number of interesting effects occur: the possibility to solve the coincidence problem, crossing of phantom divide and unification of early-time inflationary and late-time accelerating phantom universe. The bound for holographic entropy which decreases in phantom era is also discussed.

  16. The design and fabrication of two portal vein flow phantoms by different methods

    SciTech Connect

    Yunker, Bryan E. Lanning, Craig J.; Shandas, Robin; Hunter, Kendall S.; Chen, S. James

    2014-02-15

    Purpose: This study outlines the design and fabrication techniques for two portal vein flow phantoms. Methods: A materials study was performed as a precursor to this phantom fabrication effort and the desired material properties are restated for continuity. A three-dimensional portal vein pattern was created from the Visual Human database. The portal vein pattern was used to fabricate two flow phantoms by different methods with identical interior surface geometry using computer aided design software tools and rapid prototyping techniques. One portal flow phantom was fabricated within a solid block of clear silicone for use on a table with Ultrasound or within medical imaging systems such as MRI, CT, PET, or SPECT. The other portal flow phantom was fabricated as a thin walled tubular latex structure for use in water tanks with Ultrasound imaging. Both phantoms were evaluated for usability and durability. Results: Both phantoms were fabricated successfully and passed durability criteria for flow testing in the next project phase. Conclusions: The fabrication methods and materials employed for the study yielded durable portal vein phantoms.

  17. Design, development, and implementation of the Radiological Physics Center's pelvis and thorax anthropomorphic quality assurance phantoms

    SciTech Connect

    Followill, David S.; Radford Evans, DeeAnn; Cherry, Christopher; Molineu, Andrea; Fisher, Gary; Hanson, William F.; Ibbott, Geoffrey S.

    2007-06-15

    The Radiological Physics Center (RPC) developed two heterogeneous anthropomorphic quality assurance phantoms for use in verifying the accuracy of radiation delivery: one for intensity-modulated radiation therapy (IMRT) to the pelvis and the other for stereotactic body radiation therapy (SBRT) to the thorax. The purpose of this study was to describe the design and development of these two phantoms and to demonstrate the reproducibility of measurements generated with them. The phantoms were built to simulate actual patient anatomy. They are lightweight and water-fillable, and they contain imageable targets and organs at risk of radiation exposure that are of similar densities to their human counterparts. Dosimetry inserts accommodate radiochromic film for relative dosimetry and thermoluminesent dosimetry capsules for absolute dosimetry. As a part of the commissioning process, each phantom was imaged, treatment plans were developed, and radiation was delivered at least three times. Under these controlled irradiation conditions, the reproducibility of dose delivery to the target TLD in the pelvis and thorax phantoms was 3% and 0.5%, respectively. The reproducibility of radiation-field localization was less than 2.5 mm for both phantoms. Using these anthropomorphic phantoms, pelvic IMRT and thoracic SBRT radiation treatments can be verified with a high level of precision. These phantoms can be used to effectively credential institutions for participation in specific NCI-sponsored clinical trials.

  18. Monocular advantage for face perception implicates subcortical mechanisms in adult humans.

    PubMed

    Gabay, Shai; Nestor, Adrian; Dundas, Eva; Behrmann, Marlene

    2014-05-01

    The ability to recognize faces accurately and rapidly is an evolutionarily adaptive process. Most studies examining the neural correlates of face perception in adult humans have focused on a distributed cortical network of face-selective regions. There is, however, robust evidence from phylogenetic and ontogenetic studies that implicates subcortical structures, and recently, some investigations in adult humans indicate subcortical correlates of face perception as well. The questions addressed here are whether low-level subcortical mechanisms for face perception (in the absence of changes in expression) are conserved in human adults, and if so, what is the nature of these subcortical representations. In a series of four experiments, we presented pairs of images to the same or different eyes. Participants' performance demonstrated that subcortical mechanisms, indexed by monocular portions of the visual system, play a functional role in face perception. These mechanisms are sensitive to face-like configurations and afford a coarse representation of a face, comprised of primarily low spatial frequency information, which suffices for matching faces but not for more complex aspects of face perception such as sex differentiation. Importantly, these subcortical mechanisms are not implicated in the perception of other visual stimuli, such as cars or letter strings. These findings suggest a conservation of phylogenetically and ontogenetically lower-order systems in adult human face perception. The involvement of subcortical structures in face recognition provokes a reconsideration of current theories of face perception, which are reliant on cortical level processing, inasmuch as it bolsters the cross-species continuity of the biological system for face recognition.

  19. Isolation, Characterization, and Differentiation of Progenitor Cells from Human Adult Adrenal Medulla

    PubMed Central

    Santana, Magda M.; Chung, Kuei-Fang; Vukicevic, Vladimir; Rosmaninho-Salgado, Joana; Kanczkowski, Waldemar; Cortez, Vera; Hackmann, Karl; Bastos, Carlos A.; Mota, Alfredo; Schrock, Evelin; Bornstein, Stefan R.; Cavadas, Cláudia

    2012-01-01

    Chromaffin cells, sympathetic neurons of the dorsal ganglia, and the intermediate small intensely fluorescent cells derive from a common neural crest progenitor cell. Contrary to the closely related sympathetic nervous system, within the adult adrenal medulla a subpopulation of undifferentiated progenitor cells persists, and recently, we established a method to isolate and differentiate these progenitor cells from adult bovine adrenals. However, no studies have elucidated the existence of adrenal progenitor cells within the human adrenal medulla. Here we describe the isolation, characterization, and differentiation of chromaffin progenitor cells obtained from adult human adrenals. Human chromaffin progenitor cells were cultured in low-attachment conditions for 10–12 days as free-floating spheres in the presence of fibroblast growth factor-2 (FGF-2) and epidermal growth factor. These primary human chromosphere cultures were characterized by the expression of several progenitor markers, including nestin, CD133, Notch1, nerve growth factor receptor, Snai2, Sox9, Sox10, Phox2b, and Ascl1 on the molecular level and of Sox9 on the immunohistochemical level. In opposition, phenylethanolamine N-methyltransferase (PNMT), a marker for differentiated chromaffin cells, significantly decreased after 12 days in culture. Moreover, when plated on poly-l-lysine/laminin-coated slides in the presence of FGF-2, human chromaffin progenitor cells were able to differentiate into two distinct neuron-like cell types, tyrosine hydroxylase (TH)+/β-3-tubulin+ cells and TH−/β-3-tubulin+ cells, and into chromaffin cells (TH+/PNMT+). This study demonstrates the presence of progenitor cells in the human adrenal medulla and reveals their potential use in regenerative medicine, especially in the treatment of neuroendocrine and neurodegenerative diseases. PMID:23197690

  20. Isolation, characterization, and differentiation of progenitor cells from human adult adrenal medulla.

    PubMed

    Santana, Magda M; Chung, Kuei-Fang; Vukicevic, Vladimir; Rosmaninho-Salgado, Joana; Kanczkowski, Waldemar; Cortez, Vera; Hackmann, Klaus; Bastos, Carlos A; Mota, Alfredo; Schrock, Evelin; Bornstein, Stefan R; Cavadas, Cláudia; Ehrhart-Bornstein, Monika

    2012-11-01

    Chromaffin cells, sympathetic neurons of the dorsal ganglia, and the intermediate small intensely fluorescent cells derive from a common neural crest progenitor cell. Contrary to the closely related sympathetic nervous system, within the adult adrenal medulla a subpopulation of undifferentiated progenitor cells persists, and recently, we established a method to isolate and differentiate these progenitor cells from adult bovine adrenals. However, no studies have elucidated the existence of adrenal progenitor cells within the human adrenal medulla. Here we describe the isolation, characterization, and differentiation of chromaffin progenitor cells obtained from adult human adrenals. Human chromaffin progenitor cells were cultured in low-attachment conditions for 10-12 days as free-floating spheres in the presence of fibroblast growth factor-2 (FGF-2) and epidermal growth factor. These primary human chromosphere cultures were characterized by the expression of several progenitor markers, including nestin, CD133, Notch1, nerve growth factor receptor, Snai2, Sox9, Sox10, Phox2b, and Ascl1 on the molecular level and of Sox9 on the immunohistochemical level. In opposition, phenylethanolamine N-methyltransferase (PNMT), a marker for differentiated chromaffin cells, significantly decreased after 12 days in culture. Moreover, when plated on poly-l-lysine/laminin-coated slides in the presence of FGF-2, human chromaffin progenitor cells were able to differentiate into two distinct neuron-like cell types, tyrosine hydroxylase (TH)(+)/β-3-tubulin(+) cells and TH(-)/β-3-tubulin(+) cells, and into chromaffin cells (TH(+)/PNMT(+)). This study demonstrates the presence of progenitor cells in the human adrenal medulla and reveals their potential use in regenerative medicine, especially in the treatment of neuroendocrine and neurodegenerative diseases. PMID:23197690

  1. Normalizing the environment recapitulates adult human immune traits in laboratory mice.

    PubMed

    Beura, Lalit K; Hamilton, Sara E; Bi, Kevin; Schenkel, Jason M; Odumade, Oludare A; Casey, Kerry A; Thompson, Emily A; Fraser, Kathryn A; Rosato, Pamela C; Filali-Mouhim, Ali; Sekaly, Rafick P; Jenkins, Marc K; Vezys, Vaiva; Haining, W Nicholas; Jameson, Stephen C; Masopust, David

    2016-04-28

    Our current understanding of immunology was largely defined in laboratory mice, partly because they are inbred and genetically homogeneous, can be genetically manipulated, allow kinetic tissue analyses to be carried out from the onset of disease, and permit the use of tractable disease models. Comparably reductionist experiments are neither technically nor ethically possible in humans. However, there is growing concern that laboratory mice do not reflect relevant aspects of the human immune system, which may account for failures to translate disease treatments from bench to bedside. Laboratory mice live in abnormally hygienic specific pathogen free (SPF) barrier facilities. Here we show that standard laboratory mouse husbandry has profound effects on the immune system and that environmental changes produce mice with immune systems closer to those of adult humans. Laboratory mice--like newborn, but not adult, humans--lack effector-differentiated and mucosally distributed memory T cells. These cell populations were present in free-living barn populations of feral mice and pet store mice with diverse microbial experience, and were induced in laboratory mice after co-housing with pet store mice, suggesting that the environment is involved in the induction of these cells. Altering the living conditions of mice profoundly affected the cellular composition of the innate and adaptive immune systems, resulted in global changes in blood cell gene expression to patterns that more closely reflected the immune signatures of adult humans rather than neonates, altered resistance to infection, and influenced T-cell differentiation in response to a de novo viral infection. These data highlight the effects of environment on the basal immune state and response to infection and suggest that restoring physiological microbial exposure in laboratory mice could provide a relevant tool for modelling immunological events in free-living organisms, including humans. PMID:27096360

  2. Normalizing the environment recapitulates adult human immune traits in laboratory mice.

    PubMed

    Beura, Lalit K; Hamilton, Sara E; Bi, Kevin; Schenkel, Jason M; Odumade, Oludare A; Casey, Kerry A; Thompson, Emily A; Fraser, Kathryn A; Rosato, Pamela C; Filali-Mouhim, Ali; Sekaly, Rafick P; Jenkins, Marc K; Vezys, Vaiva; Haining, W Nicholas; Jameson, Stephen C; Masopust, David

    2016-04-28

    Our current understanding of immunology was largely defined in laboratory mice, partly because they are inbred and genetically homogeneous, can be genetically manipulated, allow kinetic tissue analyses to be carried out from the onset of disease, and permit the use of tractable disease models. Comparably reductionist experiments are neither technically nor ethically possible in humans. However, there is growing concern that laboratory mice do not reflect relevant aspects of the human immune system, which may account for failures to translate disease treatments from bench to bedside. Laboratory mice live in abnormally hygienic specific pathogen free (SPF) barrier facilities. Here we show that standard laboratory mouse husbandry has profound effects on the immune system and that environmental changes produce mice with immune systems closer to those of adult humans. Laboratory mice--like newborn, but not adult, humans--lack effector-differentiated and mucosally distributed memory T cells. These cell populations were present in free-living barn populations of feral mice and pet store mice with diverse microbial experience, and were induced in laboratory mice after co-housing with pet store mice, suggesting that the environment is involved in the induction of these cells. Altering the living conditions of mice profoundly affected the cellular composition of the innate and adaptive immune systems, resulted in global changes in blood cell gene expression to patterns that more closely reflected the immune signatures of adult humans rather than neonates, altered resistance to infection, and influenced T-cell differentiation in response to a de novo viral infection. These data highlight the effects of environment on the basal immune state and response to infection and suggest that restoring physiological microbial exposure in laboratory mice could provide a relevant tool for modelling immunological events in free-living organisms, including humans.

  3. Neutron dosimetry in solid water phantom

    SciTech Connect

    Benites-Rengifo, Jorge Luis; Vega-Carrillo, Hector Rene

    2014-11-07

    The neutron spectra, the Kerma and the absorbed dose due to neutrons were estimated along the incoming beam in a solid water phantom. Calculations were carried out with the MCNP5 code, where the bunker, the phantom and the model of the15 MV LINAC head were modeled. As the incoming beam goes into the phantom the neutron spectrum is modified and the dosimetric values are reduced.

  4. Neutron dosimetry in solid water phantom

    NASA Astrophysics Data System (ADS)

    Benites-Rengifo, Jorge Luis; Vega-Carrillo, Hector Rene

    2014-11-01

    The neutron spectra, the Kerma and the absorbed dose due to neutrons were estimated along the incoming beam in a solid water phantom. Calculations were carried out with the MCNP5 code, where the bunker, the phantom and the model of the15 MV LINAC head were modeled. As the incoming beam goes into the phantom the neutron spectrum is modified and the dosimetric values are reduced.

  5. Designing Instruction for Adult Learners. Second Edition. Professional Practices in Adult Education and Human Resource Development Series.

    ERIC Educational Resources Information Center

    Dean, Gary J.

    This book focuses on applying instructional design to development of classroom learning for adults. Chapter 1 presents an overview of the model and addresses concerns about use of instructional design in adult education. Chapter 2 deals with assessing and developing skills as an adult educator; a literature review on behavior, beliefs, knowledge,…

  6. Phantom perception: voluntary and involuntary nonretinal vision.

    PubMed

    Pearson, Joel; Westbrook, Fred

    2015-05-01

    Hallucinations, mental imagery, synesthesia, perceptual filling-in, and many illusions are conscious visual experiences without a corresponding retinal stimulus: what we call 'phantom perception'. Such percepts show that our experience of the world is not solely determined by direct sensory input. Some phantom percepts are voluntary, whereas others are involuntarily, occurring automatically. Here, by way of review, we compare and contrast these two types of phantom perception and their neural representations. We propose a dichotomous framework for phantom vision, analogous to the subtypes of attention: endogenous and exogenous. This framework unifies findings from different fields and species, providing a guide to study the constructive nature of conscious sensory perception.

  7. Phantom perception: voluntary and involuntary nonretinal vision.

    PubMed

    Pearson, Joel; Westbrook, Fred

    2015-05-01

    Hallucinations, mental imagery, synesthesia, perceptual filling-in, and many illusions are conscious visual experiences without a corresponding retinal stimulus: what we call 'phantom perception'. Such percepts show that our experience of the world is not solely determined by direct sensory input. Some phantom percepts are voluntary, whereas others are involuntarily, occurring automatically. Here, by way of review, we compare and contrast these two types of phantom perception and their neural representations. We propose a dichotomous framework for phantom vision, analogous to the subtypes of attention: endogenous and exogenous. This framework unifies findings from different fields and species, providing a guide to study the constructive nature of conscious sensory perception. PMID:25863415

  8. Moxidectin causes adult worm mortality of human lymphatic filarial parasite Brugia malayi in rodent models.

    PubMed

    Verma, Meenakshi; Pathak, Manisha; Shahab, Mohd; Singh, Kavita; Mitra, Kalyan; Misra-Bhattacharya, Shailja

    2014-12-01

    Moxidectin is a macrocyclic lactone belonging to milbemycin family closely related to ivermectin and is currently progressing towards Phase III clinical trial against human infection with the filaria Onchocerca volvulus (Leuckart, 1894). There is a single report on the microfilaricidal and embryostatic activity of moxidectin in case of the human lymphatic filarial parasite Brugia malayi (Brug, 1927) in Mastomys coucha (Smith) but without any adulticidal action. In the present study, the in vitro and in vivo antifilarial efficacy of moxidectin was evaluated on, B. malayi. In vitro moxidectin showed 100% reduction in adult female worm motility at 0.6 μM concentration within 7 days with 68% inhibition in the reduction of MTT (3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide dye) (which is used to detect viability of worms). A 50% inhibitory concentration (IC50) of moxidectin for adult female parasite was 0.242 μM, for male worm 0.186 μM and for microfilaria IC50 was 0.813 μM. In adult B. malayi-transplanted primary screening model (Meriones unguiculatus Milne-Edwards), moxidectin at a single optimal dose of 20 mg/kg by oral and subcutaneous route was found effective on both adult parasites and microfilariae. In secondary screening (M coucha, subcutaneously inoculated with infective larvae), moxidectin at the same dose by subcutaneous route brought about death of 49% of adult worms besides causing sterilisation in 54% of the recovered live female worms. The treated animals exhibited a continuous and sustained reduction in peripheral blood microfilaraemia throughout the observation period of 90 days. The mechanism of action of moxidectin is suggested to be similar to avermectins. The in silico studies were also designed to explore the interaction of moxidectin with glutamate-gated chloride channels of B. malayi. The docking results revealed a close interaction of moxidectin with various GluCl ligand sites of B. malayi. PMID:25651699

  9. Urinary concentrations of parabens in Chinese young adults: implications for human exposure.

    PubMed

    Ma, Wan-Li; Wang, Lei; Guo, Ying; Liu, Li-Yan; Qi, Hong; Zhu, Ning-Zheng; Gao, Chong-Jing; Li, Yi-Fan; Kannan, Kurunthachalam

    2013-10-01

    Parabens are widely used as preservatives in foods, cosmetics, and pharmaceuticals. However, recent studies have indicated that high and systemic exposure to parabens can be harmful to human health. Although a few studies have reported urinary paraben levels in western countries, studies on paraben exposure in the Chinese population are limited. China is currently a major producer of parabens in the world. In this study, 109 urine samples collected from Chinese young adults (approximately 20 years old) were analyzed for five parabens (methyl-, ethyl-, propyl-, butyl-, and benzyl-parabens) by high-performance liquid chromatography-tandem mass spectrometry. Methyl-, propyl-, and ethyl-parabens were the three major paraben analogues found in all (100%) samples. The concentration of the sum of the five parabens ranged from 0.82 to 728 ng/mL with a geometric mean value of 17.4 ng/mL. Urinary concentration of parabens was 2-fold greater in females than in males. Based on the measured urinary concentrations, daily intake of parabens by the Chinese young adults was estimated and compared with those reported for United States adults. The estimated daily intakes (EDIurine) of parabens were 18.4 and 40.8 μg/kg bw/day for Chinese males and females, respectively, values that were lower than those reported for United States adults (74.7 μg/kg bw/day). Based on the reported concentrations of parabens in foods from China and the United States, the contribution of dietary intake to EDIurine was estimated to be 5.5, 2.6, and 0.42% for Chinese males, Chinese females, and United States adults, respectively, which indicates the significance of nondietary sources of parabens to human exposures.

  10. SU-E-J-07: IGRT Gently: Evaluating Imaging Dose in Phantoms of Different Sizes

    SciTech Connect

    Morris, B; Duggar, W; Stanford, J; Yang, C

    2015-06-15

    Purpose: IGRT imaging procedures have emerged as a common method of patient position verification in radiotherapy, though imaging dose is generally neglected in the treatment plan. Consequently, evaluating and optimizing the dose from these procedures is worthwhile. This process is especially important for children, who are more radiosensitive than adults. The aim of this work was to gain some understanding of the relative doses involved with various XVI-preset parameters for an “adult” and “child” phantom set, with the hopes that imaging dose for a child can be reduced. Methods: 32 and 16cm CTDI-phantoms were used as surrogates for adult and child torsos, respectively. Dose was measured in the central and peripheral chamber positions of the phantoms. CBCT scans were made for both phantoms using Elekta’s Chest-preset to establish a dose baseline. The child-phantom was then scanned using the Elekta Head and Neck (HN) preset. A modified HN-preset (named Peds Abd-pelvis) was also created with a doubled mAs to maintain a reduction in dose to the child-phantom (relative to the baseline), while providing clinically-usable image quality. Results: The baseline dose to the child-phantom from the Chest-preset was 310% that of the adult-phantom for the center chamber position and 150% at the periphery. An average dose reduction of 97% was obtained in the childphantom by switching from the Chest-preset to the HN-preset, while the Peds Abd-pelvis-preset similarly reduced the dose by an average of 92%. Conclusion: XVI-preset parameters significantly affect dose, and should be optimized to reduce dose, while ensuring clinically-usable image quality. Using a modified imaging preset (Peds Abd-pelvis-preset) greatly reduced the dose to the child-phantom compared to the dose for the Chest-preset for both the child and adult-phantoms. This outcome provides support for the development of child-specific protocols for IGRT imaging in pediatric patients.

  11. Populations of subplate and interstitial neurons in fetal and adult human telencephalon

    PubMed Central

    Judaš, Miloš; Sedmak, Goran; Pletikos, Mihovil; Jovanov-Milošević, Nataša

    2010-01-01

    In the adult human telencephalon, subcortical (gyral) white matter contains a special population of interstitial neurons considered to be surviving descendants of fetal subplate neurons [Kostovic & Rakic (1980) Cytology and the time of origin of interstitial neurons in the white matter in infant and adult human and monkey telencephalon. J Neurocytol9, 219]. We designate this population of cells as superficial (gyral) interstitial neurons and describe their morphology and distribution in the postnatal and adult human cerebrum. Human fetal subplate neurons cannot be regarded as interstitial, because the subplate zone is an essential part of the fetal cortex, the major site of synaptogenesis and the ‘waiting’ compartment for growing cortical afferents, and contains both projection neurons and interneurons with distinct input–output connectivity. However, although the subplate zone is a transient fetal structure, many subplate neurons survive postnatally as superficial (gyral) interstitial neurons. The fetal white matter is represented by the intermediate zone and well-defined deep periventricular tracts of growing axons, such as the corpus callosum, anterior commissure, internal and external capsule, and the fountainhead of the corona radiata. These tracts gradually occupy the territory of transient fetal subventricular and ventricular zones.The human fetal white matter also contains distinct populations of deep fetal interstitial neurons, which, by virtue of their location, morphology, molecular phenotypes and advanced level of dendritic maturation, remain distinct from subplate neurons and neurons in adjacent structures (e.g. basal ganglia, basal forebrain). We describe the morphological, histochemical (nicotinamide-adenine dinucleotide phosphate-diaphorase) and immunocytochemical (neuron-specific nuclear protein, microtubule-associated protein-2, calbindin, calretinin, neuropeptide Y) features of both deep fetal interstitial neurons and deep (periventricular

  12. Drosophila as a model for the identification of genes causing adult human heart disease

    PubMed Central

    Wolf, Matthew J.; Amrein, Hubert; Izatt, Joseph A.; Choma, Michael A.; Reedy, Mary C.; Rockman, Howard A.

    2006-01-01

    Drosophila melanogaster genetics provides the advantage of molecularly defined P-element insertions and deletions that span the entire genome. Although Drosophila has been extensively used as a model system to study heart development, it has not been used to dissect the genetics of adult human heart disease because of an inability to phenotype the adult fly heart in vivo. Here we report the development of a strategy to measure cardiac function in awake adult Drosophila that opens the field of Drosophila genetics to the study of human dilated cardiomyopathies. Through the application of optical coherence tomography, we accurately distinguish between normal and abnormal cardiac function based on measurements of internal cardiac chamber dimensions in vivo. Normal Drosophila have a fractional shortening of 87 ± 4%, whereas cardiomyopathic flies that contain a mutation in troponin I or tropomyosin show severe impairment of systolic function. To determine whether the fly can be used as a model system to recapitulate human dilated cardiomyopathy, we generated transgenic Drosophila with inducible cardiac expression of a mutant of human δ-sarcoglycan (δsgS151A), which has previously been associated with familial dilated cardiomyopathy. Compared to transgenic flies overexpressing wild-type δsg, or the standard laboratory strain w1118, Drosophila expressing δsgS151A developed marked impairment of systolic function and significantly enlarged cardiac chambers. These data illustrate the utility of Drosophila as a model system to study dilated cardiomyopathy and the applicability of the vast genetic resources available in Drosophila to systematically study the genetic mechanisms responsible for human cardiac disease. PMID:16432241

  13. Rabbit Neonates and Human Adults Perceive a Blending 6-Component Odor Mixture in a Comparable Manner

    PubMed Central

    Sinding, Charlotte; Thomas-Danguin, Thierry; Chambault, Adeline; Béno, Noelle; Dosne, Thibaut; Chabanet, Claire; Schaal, Benoist; Coureaud, Gérard

    2013-01-01

    Young and adult mammals are constantly exposed to chemically complex stimuli. The olfactory system allows for a dual processing of relevant information from the environment either as single odorants in mixtures (elemental perception) or as mixtures of odorants as a whole (configural perception). However, it seems that human adults have certain limits in elemental perception of odor mixtures, as suggested by their inability to identify each odorant in mixtures of more than 4 components. Here, we explored some of these limits by evaluating the perception of three 6-odorant mixtures in human adults and newborn rabbits. Using free-sorting tasks in humans, we investigated the configural or elemental perception of these mixtures, or of 5-component sub-mixtures, or of the 6-odorant mixtures with modified odorants' proportion. In rabbit pups, the perception of the same mixtures was evaluated by measuring the orocephalic sucking response to the mixtures or their components after conditioning to one of these stimuli. The results revealed that one mixture, previously shown to carry the specific odor of red cordial in humans, was indeed configurally processed in humans and in rabbits while the two other 6-component mixtures were not. Moreover, in both species, such configural perception was specific not only to the 6 odorants included in the mixture but also to their respective proportion. Interestingly, rabbit neonates also responded to each odorant after conditioning to the red cordial mixture, which demonstrates their ability to perceive elements in addition to configuration in this complex mixture. Taken together, the results provide new insights related to the processing of relatively complex odor mixtures in mammals and the inter-species conservation of certain perceptual mechanisms; the results also revealed some differences in the expression of these capacities between species putatively linked to developmental and ecological constraints. PMID:23341948

  14. Computerized quantitative evaluation of mammographic accreditation phantom images

    SciTech Connect

    Lee, Yongbum; Tsai, Du-Yih; Shinohara, Norimitsu

    2010-12-15

    Purpose: The objective was to develop and investigate an automated scoring scheme of the American College of Radiology (ACR) mammographic accreditation phantom (RMI 156, Middleton, WI) images. Methods: The developed method consisted of background subtraction, determination of region of interest, classification of fiber and mass objects by Mahalanobis distance, detection of specks by template matching, and rule-based scoring. Fifty-one phantom images were collected from 51 facilities for this study (one facility provided one image). A medical physicist and two radiologic technologists also scored the images. The human and computerized scores were compared. Results: In terms of meeting the ACR's criteria, the accuracies of the developed method for computerized evaluation of fiber, mass, and speck were 90%, 80%, and 98%, respectively. Contingency table analysis revealed significant association between observer and computer scores for microcalcifications (p<5%) but not for masses and fibers. Conclusions: The developed method may achieve a stable assessment of visibility for test objects in mammographic accreditation phantom image in whether the phantom image meets the ACR's criteria in the evaluation test, although there is room left for improvement in the approach for fiber and mass objects.

  15. Control volume based hydrocephalus research; a phantom study

    NASA Astrophysics Data System (ADS)

    Cohen, Benjamin; Voorhees, Abram; Madsen, Joseph; Wei, Timothy

    2009-11-01

    Hydrocephalus is a complex spectrum of neurophysiological disorders involving perturbation of the intracranial contents; primarily increased intraventricular cerebrospinal fluid (CSF) volume and intracranial pressure are observed. CSF dynamics are highly coupled to the cerebral blood flows and pressures as well as the mechanical properties of the brain. Hydrocephalus, as such, is a very complex biological problem. We propose integral control volume analysis as a method of tracking these important interactions using mass and momentum conservation principles. As a first step in applying this methodology in humans, an in vitro phantom is used as a simplified model of the intracranial space. The phantom's design consists of a rigid container filled with a compressible gel. Within the gel a hollow spherical cavity represents the ventricular system and a cylindrical passage represents the spinal canal. A computer controlled piston pump supplies sinusoidal volume fluctuations into and out of the flow phantom. MRI is used to measure fluid velocity and volume change as functions of time. Independent pressure measurements and momentum flow rate measurements are used to calibrate the MRI data. These data are used as a framework for future work with live patients and normal individuals. Flow and pressure measurements on the flow phantom will be presented through the control volume framework.

  16. Comparison of human growth hormone products' cost in pediatric and adult patients. A budgetary impact model.

    PubMed

    Bazalo, Gary R; Joshi, Ashish V; Germak, John

    2007-09-01

    We assessed the economic impact to the United States payer of recombinant human growth hormone (rhGH) utilization, comparing the relative dosage efficiency of marketed pen-based and vial-based products in a pediatric and in an adult population. A budgetary impact model calculated drug costs based on product waste and cost. Waste was the difference between prescribed dose, based on patient weight, and actual delivered dose, based on dosing increments and maximum deliverable dose for pens and a fixed-percent waste as derived from the literature for vials. Annual wholesale acquisition costs were calculated based upon total milligrams delivered, using a daily dose of 0.03 mg/kg for pediatric patients and 0.016 mg/kg for adults. Total annual drug costs were compared for two scenarios: 1) a product mix based on national market share and 2) restricting use to the product with lowest waste. Based on the literature, waste for each vial product was 23 percent. Among individual pens, waste was highest for Humatrope 24 mg (19.5 percent pediatric, 14.3 percent adult) and lowest for Norditropin Nordi-Flex 5 mg (1.1 percent pediatric, 1 percent adult). Restricting use to the brand with least waste (Norditropin), compared to national product share mix, resulted in a 10.2 percent reduction in annual pediatric patient cost from $19,026 to $17,089 and an 8 percent reduction in annual adult patient cost from $24,099 to $22,161. We concluded that pen delivery systems result in less waste than vial and syringe. Considering all approved delivery systems, Norditropin resulted in the least product waste and lower annual patient cost for both pediatric and adult populations.

  17. The phantom limb in dreams.

    PubMed

    Brugger, Peter

    2008-12-01

    Mulder and colleagues [Mulder, T., Hochstenbach, J., Dijkstra, P. U., Geertzen, J. H. B. (2008). Born to adapt, but not in your dreams. Consciousness and Cognition, 17, 1266-1271.] report that a majority of amputees continue to experience a normally-limbed body during their night dreams. They interprete this observation as a failure of the body schema to adapt to the new body shape. The present note does not question this interpretation, but points to the already existing literature on the phenomenology of the phantom limb in dreams. A summary of published investigations is complemented by a note on phantom phenomena in the dreams of paraplegic patients and persons born without a limb. Integration of the available data allows the recommendation for prospective studies to consider dream content in more detail. For instance, "adaptation" to the loss of a limb can also manifest itself by seeing oneself surrounded by amputees. Such projective types of anosognosia ("transitivism") in nocturnal dreams should also be experimentally induced in normally-limbed individuals, and some relevant techniques are mentioned.

  18. Transorbital therapy delivery: phantom testing

    NASA Astrophysics Data System (ADS)

    Ingram, Martha-Conley; Atuegwu, Nkiruka; Mawn, Louise; Galloway, Robert L.

    2011-03-01

    We have developed a combined image-guided and minimally invasive system for the delivery of therapy to the back of the eye. It is composed of a short 4.5 mm diameter endoscope with a magnetic tracker embedded in the tip. In previous work we have defined an optimized fiducial placement for accurate guidance to the back of the eye and are now moving to system testing. The fundamental difficulty in testing performance is establishing a target in a manner which closely mimics the physiological task. We have to have a penetrable material which obscures line of sight, similar to the orbital fat. In addition we need to have some independent measure of knowing when a target has been reached to compare to the ideal performance. Lastly, the target cannot be rigidly attached to the skull phantom since the optic nerve lies buried in the orbital fat. We have developed a skull phantom with white cloth stellate balls supporting a correctly sized globe. Placed in the white balls are red, blue, orange and yellow balls. One of the colored balls has been soaked in barium to make it bright on CT. The user guides the tracked endoscope to the target as defined by the images and tells us its color. We record task accuracy and time to target. We have tested this with 28 residents, fellows and attending physicians. Each physician performs the task twice guided and twice unguided. Results will be presented.

  19. The mental representation of the human gait in young and older adults

    PubMed Central

    Stöckel, Tino; Jacksteit, Robert; Behrens, Martin; Skripitz, Ralf; Bader, Rainer; Mau-Moeller, Anett

    2015-01-01

    The link between mental representation (MREP) structures and motor performance has been evidenced for a great variety of movement skills, but not for the human gait. Therefore the present study sought to investigate the cognitive memory structures underlying the human gait in young and older adults. In a first experiment, gait parameters at comfortable gait speed (OptoGait) were compared with gait-specific MREPs (structural dimensional analysis of MREP; SDA-M) in 36 young adults. Participants were divided into a slow- and fast-walking group. The proven relationship between gait speed and executive functions such as working memory led to the hypothesis that gait pattern and MREP differ between slow- and fast-walking adults. In a second experiment, gait performance and MREPs were compared between 24 young (27.9 years) and 24 elderly (60.1 years) participants. As age-related declines in gait performance occur from the seventh decade of life onward, we hypothesized that gait parameters would not be affected until the age of 60 years accompanied by unchanged MREP. Data of experiment one revealed that gait parameters and MREPs differed significantly between slow and fast walkers. Notably, eleven previously incurred musculoskeletal injuries were documented for the slow walkers but only two injuries and one disorder for fast walkers. Experiment two revealed no age-related differences in gait parameters or MREPs between healthy young and older adults. In conclusion, the differences in gait parameters associated with lower comfortable gait speeds are reflected by differences in MREPs, whereby SDA-M data indicate that the single limb support phase may serve as a critical functional period. These differences probably resulted from previously incurred musculoskeletal injuries. Our data further indicate that the human gait and its MREP are stable until the age of 60. SDA-M may be considered as a valuable clinical tool for diagnosis of gait abnormalities and monitoring of

  20. The Ecology of Human Performance Framework: A Model for Identifying and Designing Appropriate Accommodations for Adult Learners.

    ERIC Educational Resources Information Center

    Dunn, Winnie; Gilbert, Mary Pat; Parker, Kathy

    This paper proposes a model framework, The Ecology of Human Performance (EHP) framework, for organizing adult basic education to utilize the skills of occupational therapists. The paper also includes two responses to the proposed framework by Janet S. Stotts and Cheryl Keenan. Reasons for the inclusion of occupational therapy in adult education…

  1. 40 CFR 26.1704 - Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 1 2014-07-01 2014-07-01 false Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults. 26.1704 Section 26.1704 Protection of Environment... research with non-pregnant, non-nursing adults. (a) This section applies to research subject to...

  2. 40 CFR 26.1704 - Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 1 2013-07-01 2013-07-01 false Prohibition of reliance on unethical human research with non-pregnant, non-nursing adults. 26.1704 Section 26.1704 Protection of Environment... research with non-pregnant, non-nursing adults. (a) This section applies to research subject to...

  3. Optical characterization of tissue mimicking phantoms by a vertical double integrating sphere system

    NASA Astrophysics Data System (ADS)

    Han, Yilin; Jia, Qiumin; Shen, Shuwei; Liu, Guangli; Guo, Yuwei; Zhou, Ximing; Chu, Jiaru; Zhao, Gang; Dong, Erbao; Allen, David W.; Lemaillet, Paul; Xu, Ronald

    2016-03-01

    Accurate characterization of absorption and scattering properties for biologic tissue and tissue-simulating materials enables 3D printing of traceable tissue-simulating phantoms for medical spectral device calibration and standardized medical optical imaging. Conventional double integrating sphere systems have several limitations and are suboptimal for optical characterization of liquid and soft materials used in 3D printing. We propose a vertical double integrating sphere system and the associated reconstruction algorithms for optical characterization of phantom materials that simulate different human tissue components. The system characterizes absorption and scattering properties of liquid and solid phantom materials in an operating wavelength range from 400 nm to 1100 nm. Absorption and scattering properties of the phantoms are adjusted by adding titanium dioxide powder and India ink, respectively. Different material compositions are added in the phantoms and characterized by the vertical double integrating sphere system in order to simulate the human tissue properties. Our test results suggest that the vertical integrating sphere system is able to characterize optical properties of tissue-simulating phantoms without precipitation effect of the liquid samples or wrinkling effect of the soft phantoms during the optical measurement.

  4. Maternal and child undernutrition: consequences for adult health and human capital.

    PubMed

    Victora, Cesar G; Adair, Linda; Fall, Caroline; Hallal, Pedro C; Martorell, Reynaldo; Richter, Linda; Sachdev, Harshpal Singh

    2008-01-26

    In this paper we review the associations between maternal and child undernutrition with human capital and risk of adult diseases in low-income and middle-income countries. We analysed data from five long-standing prospective cohort studies from Brazil, Guatemala, India, the Philippines, and South Africa and noted that indices of maternal and child undernutrition (maternal height, birthweight, intrauterine growth restriction, and weight, height, and body-mass index at 2 years according to the new WHO growth standards) were related to adult outcomes (height, schooling, income or assets, offspring birthweight, body-mass index, glucose concentrations, blood pressure). We undertook systematic reviews of studies from low-income and middle-income countries for these outcomes and for indicators related to blood lipids, cardiovascular disease, lung and immune function, cancers, osteoporosis, and mental illness. Undernutrition was strongly associated, both in the review of published work and in new analyses, with shorter adult height, less schooling, reduced economic productivity, and--for women--lower offspring birthweight. Associations with adult disease indicators were not so clear-cut. Increased size at birth and in childhood were positively associated with adult body-mass index and to a lesser extent with blood pressure values, but not with blood glucose concentrations. In our new analyses and in published work, lower birthweight and undernutrition in childhood were risk factors for high glucose concentrations, blood pressure, and harmful lipid profiles once adult body-mass index and height were adjusted for, suggesting that rapid postnatal weight gain--especially after infancy--is linked to these conditions. The review of published works indicates that there is insufficient information about long-term changes in immune function, blood lipids, or osteoporosis indicators. Birthweight is positively associated with lung function and with the incidence of some cancers, and

  5. Isoforms of Hsp70-binding human LDL in adult Schistosoma mansoni worms.

    PubMed

    Pereira, Adriana S A; Cavalcanti, Marília G S; Zingali, Russolina B; Lima-Filho, José L; Chaves, Maria E C

    2015-03-01

    Schistosoma mansoni is one of the most common parasites infecting humans. They are well adapted to the host, and this parasite's longevity is a consequence of effective escape from the host immune system. In the blood circulation, lipoproteins not only help to conceal the worm from attack by host antibodies but also act as a source of lipids for S. mansoni. Previous SEM studies showed that the low-density lipoprotein (LDL) particles present on the surface of adult S. mansoni worms decreased in size when the incubation time increased. In this study, immunocytochemical and proteomic analyses were used to locate and identify S. mansoni binding proteins to human plasma LDL. Ultrathin sections of adult worms were cut transversely from the anterior, medial and posterior regions of the parasite. Immunocytochemical experiments revealed particles of gold in the tegument, muscle region and spine in male worms and around vitelline cells in females. Immunoblotting and 2D-electrophoresis using incubations with human serum, anti-LDL antibodies and anti-chicken IgG peroxidase conjugate were performed to identify LDL-binding proteins in S. mansoni. Analysis of the binding proteins using LC-MS identified two isoforms of the Hsp70 chaperone in S. mansoni. Hsp70 is involved in the interaction with apoB in the cytoplasm and its transport to the endoplasmic reticulum. However, further studies are needed to clarify the functional role of Hsp70 in S. mansoni, mainly related to the interaction with human LDL.

  6. Uptake of dietary milk miRNAs by adult humans: a validation study

    PubMed Central

    Auerbach, Amanda; Vyas, Gopi; Li, Anne; Halushka, Marc; Witwer, Kenneth

    2016-01-01

    Breast milk is replete with nutritional content as well as nucleic acids including microRNAs (miRNAs). In a recent report, adult humans who drank bovine milk appeared to have increased circulating levels of miRNAs miR-29b-3p and miR-200c-3p. Since these miRNAs are homologous between human and cow, these results could be explained by xeno-miRNA influx, endogenous miRNA regulation, or both. More data were needed to validate the results and explore for additional milk-related alterations in circulating miRNAs. Samples from the published study were obtained, and 223 small RNA features were profiled with a custom OpenArray, followed by individual quantitative PCR assays for selected miRNAs. Additionally, small RNA sequencing (RNA-seq) data obtained from plasma samples of the same project were analyzed to find human and uniquely bovine miRNAs. OpenArray revealed no significantly altered miRNA signals after milk ingestion, and this was confirmed by qPCR. Plasma sequencing data contained no miR-29b or miR-200c reads and no intake-consistent mapping of uniquely bovine miRNAs. In conclusion, the results do not support transfer of dietary xenomiRs into the circulation of adult humans. PMID:27158459

  7. Identification of novel molecular markers through transcriptomic analysis in human fetal and adult corneal endothelial cells.

    PubMed

    Chen, Yinyin; Huang, Kevin; Nakatsu, Martin N; Xue, Zhigang; Deng, Sophie X; Fan, Guoping

    2013-04-01

    The corneal endothelium is composed of a monolayer of corneal endothelial cells (CECs), which is essential for maintaining corneal transparency. To better characterize CECs in different developmental stages, we profiled mRNA transcriptomes in human fetal and adult corneal endothelium with the goal to identify novel molecular markers in these cells. By comparing CECs with 12 other tissue types, we identified 245 and 284 signature genes that are highly expressed in fetal and adult CECs, respectively. Functionally, these genes are enriched in pathways characteristic of CECs, including inorganic anion transmembrane transporter, extracellular matrix structural constituent and cyclin-dependent protein kinase inhibitor activity. Importantly, several of these genes are disease target genes in hereditary corneal dystrophies, consistent with their functional significance in CEC physiology. We also identified stage-specific markers associated with CEC development, such as specific members in the transforming growth factor beta and Wnt signaling pathways only expressed in fetal, but not in adult CECs. Lastly, by the immunohistochemistry of ocular tissues, we demonstrated the unique protein localization for Wnt5a, S100A4, S100A6 and IER3, the four novel markers for fetal and adult CECs. The identification of a new panel of stage-specific markers for CECs would be very useful for characterizing CECs derived from stem cells or ex vivo expansion for cell replacement therapy. PMID:23257286

  8. Adult education as a human right: The Latin American context and the ecopedagogic perspective

    NASA Astrophysics Data System (ADS)

    Gadotti, Moacir

    2011-08-01

    This article presents the concept and practice of adult education as a key issue for Brazil and other Latin American countries, both for formal and non-formal education in the public and private sectors. It includes citizen education focused on democratisation of society and sustainable development. The concept is pluralist and ideological as well as technical. All along the history of contemporary education it is essential to highlight the importance of the CONFINTEA conferences for the construction of an expanded vision of this concept. Adult education is understood as a human right. The right to education does not end when a person has reached the so-called "proper" age; it continues to be a right for the duration of everyone's entire life. This article explores Paulo Freire's contribution, particularly the methodology of MOVA (Youth and Adult Literacy Movement). It also presents the ecopedagogic perspective, which was inspired by Paulo Freire's legacy. Finally, this article stresses the need to support a long-term policy for adult education, following the recommendations of the Civil Society International Forum (FISC) and CONFINTEA VI, both held in Belém, Brazil, in 2009.

  9. Color-matched and fluorescence-labeled esophagus phantom and its applications

    PubMed Central

    Hou, Vivian; Nelson, Leonard Y.; Seibel, Eric J.

    2013-01-01

    Abstract. We developed a stable, reproducible three-dimensional optical phantom for the evaluation of a wide-field endoscopic molecular imaging system. This phantom mimicked a human esophagus structure with flexibility to demonstrate body movements. At the same time, realistic visual appearance and diffuse spectral reflectance properties of the tissue were simulated by a color matching methodology. A photostable dye-in-polymer technology was applied to represent biomarker probed “hot-spot” locations. Furthermore, fluorescent target quantification of the phantom was demonstrated using a 1.2 mm ultrathin scanning fiber endoscope with concurrent fluorescence-reflectance imaging. PMID:23403908

  10. Bone tissue phantoms for optical flowmeters at large interoptode spacing generated by 3D-stereolithography

    PubMed Central

    Binzoni, Tiziano; Torricelli, Alessandro; Giust, Remo; Sanguinetti, Bruno; Bernhard, Paul; Spinelli, Lorenzo

    2014-01-01

    A bone tissue phantom prototype allowing to test, in general, optical flowmeters at large interoptode spacings, such as laser-Doppler flowmetry or diffuse correlation spectroscopy, has been developed by 3D-stereolithography technique. It has been demonstrated that complex tissue vascular systems of any geometrical shape can be conceived. Absorption coefficient, reduced scattering coefficient and refractive index of the optical phantom have been measured to ensure that the optical parameters reasonably reproduce real human bone tissue in vivo. An experimental demonstration of a possible use of the optical phantom, utilizing a laser-Doppler flowmeter, is also presented. PMID:25136496

  11. Bone tissue phantoms for optical flowmeters at large interoptode spacing generated by 3D-stereolithography.

    PubMed

    Binzoni, Tiziano; Torricelli, Alessandro; Giust, Remo; Sanguinetti, Bruno; Bernhard, Paul; Spinelli, Lorenzo

    2014-08-01

    A bone tissue phantom prototype allowing to test, in general, optical flowmeters at large interoptode spacings, such as laser-Doppler flowmetry or diffuse correlation spectroscopy, has been developed by 3D-stereolithography technique. It has been demonstrated that complex tissue vascular systems of any geometrical shape can be conceived. Absorption coefficient, reduced scattering coefficient and refractive index of the optical phantom have been measured to ensure that the optical parameters reasonably reproduce real human bone tissue in vivo. An experimental demonstration of a possible use of the optical phantom, utilizing a laser-Doppler flowmeter, is also presented.

  12. Intercomparison of whole-body counters using a multinuclide calibration phantom.

    PubMed

    Fenwick, J D; McKenzie, A L; Boddy, K

    1991-02-01

    Whole-body counters in the UK have been compared using a multinuclide anthropomorphic phantom. A standard Bush phantom was modified by inserting channels into the long axis of each section. Radionuclide sources sealed in a urea-formaldehyde polymer were then inserted into the channels to simulate distributions of radioactivity in a human. The phantom was taken to 10 whole-body counters in the UK and estimates of 134Cs, 137Cs and 40K were obtained both separately and as mixtures. Results showed close agreement between the median estimates and the known activities. The technique also allowed diagnosis of particular problems in calibration for several of the counters.

  13. Bone tissue phantoms for optical flowmeters at large interoptode spacing generated by 3D-stereolithography.

    PubMed

    Binzoni, Tiziano; Torricelli, Alessandro; Giust, Remo; Sanguinetti, Bruno; Bernhard, Paul; Spinelli, Lorenzo

    2014-08-01

    A bone tissue phantom prototype allowing to test, in general, optical flowmeters at large interoptode spacings, such as laser-Doppler flowmetry or diffuse correlation spectroscopy, has been developed by 3D-stereolithography technique. It has been demonstrated that complex tissue vascular systems of any geometrical shape can be conceived. Absorption coefficient, reduced scattering coefficient and refractive index of the optical phantom have been measured to ensure that the optical parameters reasonably reproduce real human bone tissue in vivo. An experimental demonstration of a possible use of the optical phantom, utilizing a laser-Doppler flowmeter, is also presented. PMID:25136496

  14. Color-matched and fluorescence-labeled esophagus phantom and its applications

    NASA Astrophysics Data System (ADS)

    Yang, Chenying; Hou, Vivian; Nelson, Leonard Y.; Seibel, Eric J.

    2013-02-01

    We developed a stable, reproducible three-dimensional optical phantom for the evaluation of a wide-field endoscopic molecular imaging system. This phantom mimicked a human esophagus structure with flexibility to demonstrate body movements. At the same time, realistic visual appearance and diffuse spectral reflectance properties of the tissue were simulated by a color matching methodology. A photostable dye-in-polymer technology was applied to represent biomarker probed "hot-spot" locations. Furthermore, fluorescent target quantification of the phantom was demonstrated using a 1.2 mm ultrathin scanning fiber endoscope with concurrent fluorescence-reflectance imaging.

  15. Oral Human Papillomavirus Detection in Older Adults Who Have Human Immunodeficiency Virus Infection

    PubMed Central

    Fatahzadeh, Mahnaz; Schlecht, Nicolas F.; Chen, Zigui; Bottalico, Danielle; McKinney, Sharod; Ostoloza, Janae; Dunne, Anne; Burk, Robert D.

    2014-01-01

    Objective To evaluate reproducibility of oral rinse self-collection for HPV detection and investigate associations between oral HPV, oral lesions, immune and sociodemographic factors, we performed a cross-sectional study of older adults with HIV infection. Study Design We collected oral rinse samples from 52 subjects at two different times of day followed by an oral examination and interview. We identified HPV using PCR platforms optimized for detection of mucosal and cutaneous types. Results Eighty seven percent of individuals had oral HPV, of which 23% had oncogenic alpha, 40% had non-oncogenic alpha, and 46% had beta or gamma HPV. Paired oral specimens were concordant in all parameters tested. Significant associations observed for oral HPV with increased HIV viral load, hepatitis-C seropositivity, history of sexually transmitted diseases and lifetime number of sexual partners. Conclusions Oral cavity may be a reservoir of subclinical HPV in older adults who have HIV infection. Understanding natural history, transmission and potential implications of oral HPV warrants further investigations. PMID:23375488

  16. Adoptive transfer of macrophages from adult mice reduces mortality in mice infected with human enterovirus 71.

    PubMed

    Liu, Jiangning; Li, Xiaoying; Fan, Xiaoxu; Ma, Chunmei; Qin, Chuan; Zhang, Lianfeng

    2013-02-01

    Human enterovirus 71 (EV71) causes hand, foot and mouth disease in children under 6 years of age, and the neurological complications of this virus can lead to death. Until now, no vaccines or drugs have been available for the clinical control of this epidemic. Macrophages can engulf pathogens and mediate a series of host immune responses that play a role in the defence against infectious diseases. Using immunohistochemistry, we observed the localizations of virus in muscle tissues of EV71-infected mice. The macrophages isolated from the adult mice could kill the virus gradually in vitro, as shown using quantitative real-time PCR (qRT-PCR) and virus titration. Co-localisation of lysosomes and virus within macrophages suggested that the lysosomes were possibly responsible for the phagocytosis of EV71. Activation of the macrophages in the peritoneal cavity of mice four days pre-infection reduced the mortality of mice upon lethal EV71 infection. The adoptive transfer of macrophages from adult mice inhibited virus replication in the muscle tissues of infected mice, and this was followed by a relief of symptoms and a significant reduction of mortality, which suggested that the adoptive transfer of macrophages from adult humans represents a potential strategy to treat EV71-infected patients.

  17. Acceptance and Attitudes Toward a Human-like Socially Assistive Robot by Older Adults.

    PubMed

    Louie, Wing-Yue Geoffrey; McColl, Derek; Nejat, Goldie

    2014-01-01

    Recent studies have shown that cognitive and social interventions are crucial to the overall health of older adults including their psychological, cognitive, and physical well-being. However, due to the rapidly growing elderly population of the world, the resources and people to provide these interventions is lacking. Our work focuses on the use of social robotic technologies to provide person-centered cognitive interventions. In this article, we investigate the acceptance and attitudes of older adults toward the human-like expressive socially assistive robot Brian 2.1 in order to determine if the robot's human-like assistive and social characteristics would promote the use of the robot as a cognitive and social interaction tool to aid with activities of daily living. The results of a robot acceptance questionnaire administered during a robot demonstration session with a group of 46 elderly adults showed that the majority of the individuals had positive attitudes toward the socially assistive robot and its intended applications.

  18. [Computer simulated images of radiopharmaceutical distributions in anthropomorphic phantoms

    SciTech Connect

    Not Available

    1991-05-17

    We have constructed an anatomically correct human geometry, which can be used to store radioisotope concentrations in 51 various internal organs. Each organ is associated with an index number which references to its attenuating characteristics (composition and density). The initial development of Computer Simulated Images of Radiopharmaceuticals in Anthropomorphic Phantoms (CSIRDAP) over the first 3 years has been very successful. All components of the simulation have been coded, made operational and debugged.

  19. Use of optical skin phantoms for preclinical evaluation of laser efficiency for skin lesion therapy.

    PubMed

    Wróbel, Maciej S; Jedrzejewska-Szczerska, Malgorzata; Galla, Stanislaw; Piechowski, Leszek; Sawczak, Miroslaw; Popov, Alexey P; Bykov, Alexander V; Tuchin, Valery V; Cenian, Adam

    2015-08-01

    Skin lesions are commonly treated using laser heating. However, the introduction of new devices into clinical practice requires evaluation of their performance. This study presents the application of optical phantoms for assessment of a newly developed 975-nm pulsed diode laser system for dermatological purposes. Such phantoms closely mimic the absorption and scattering of real human skin (although not precisely in relation to thermal conductivity and capacitance); thus, they can be used as substitutes for human skin for approximate evaluation of laser heating efficiency in an almost real environment. Thermographic imaging was applied to measure the spatial and temporal temperature distributions on the surface of laser-irradiated phantoms. The study yielded results of heating with regard to phantom thickness and absorption, as well as laser settings. The methodology developed can be used in practice for preclinical evaluations of laser treatment for dermatology.

  20. Use of optical skin phantoms for preclinical evaluation of laser efficiency for skin lesion therapy

    PubMed Central

    Wróbel, Maciej S.; Jędrzejewska-Szczerska, Malgorzata; Galla, Stanislaw; Piechowski, Leszek; Sawczak, Miroslaw; Popov, Alexey P.; Bykov, Alexander V.; Tuchin, Valery V.; Cenian, Adam

    2015-01-01

    Abstract. Skin lesions are commonly treated using laser heating. However, the introduction of new devices into clinical practice requires evaluation of their performance. This study presents the application of optical phantoms for assessment of a newly developed 975-nm pulsed diode laser system for dermatological purposes. Such phantoms closely mimic the absorption and scattering of real human skin (although not precisely in relation to thermal conductivity and capacitance); thus, they can be used as substitutes for human skin for approximate evaluation of laser heating efficiency in an almost real environment. Thermographic imaging was applied to measure the spatial and temporal temperature distributions on the surface of laser-irradiated phantoms. The study yielded results of heating with regard to phantom thickness and absorption, as well as laser settings. The methodology developed can be used in practice for preclinical evaluations of laser treatment for dermatology. PMID:26263414

  1. Physical Exercise Habits Correlate with Gray Matter Volume of the Hippocampus in Healthy Adult Humans

    NASA Astrophysics Data System (ADS)

    Killgore, William D. S.; Olson, Elizabeth A.; Weber, Mareen

    2013-12-01

    Physical activity facilitates neurogenesis of dentate cells in the rodent hippocampus, a brain region critical for memory formation and spatial representation. Recent findings in humans also suggest that aerobic exercise can lead to increased hippocampal volume and enhanced cognitive functioning in children and elderly adults. However, the association between physical activity and hippocampal volume during the period from early adulthood through middle age has not been effectively explored. Here, we correlated the number of minutes of self-reported exercise per week with gray matter volume of the hippocampus using voxel-based morphometry (VBM) in 61 healthy adults ranging from 18 to 45 years of age. After controlling for age, gender, and total brain volume, total minutes of weekly exercise correlated significantly with volume of the right hippocampus. Findings highlight the relationship between regular physical exercise and brain structure during early to middle adulthood.

  2. Health and population effects of rare gene knockouts in adult humans with related parents

    PubMed Central

    Narasimhan, Vagheesh M.; Hunt, Karen A.; Mason, Dan; Baker, Christopher L.; Karczewski, Konrad J.; Barnes, Michael R.; Barnett, Anthony H.; Bates, Chris; Bellary, Srikanth; Bockett, Nicholas A.; Giorda, Kristina; Griffiths, Christopher J.; Hemingway, Harry; Jia, Zhilong; Kelly, M. Ann; Khawaja, Hajrah A.; Lek, Monkol; McCarthy, Shane; McEachan, Rosie; O’Donnell-Luria, Anne; Paigen, Kenneth; Parisinos, Constantinos A.; Sheridan, Eamonn; Southgate, Laura; Tee, Louise; Thomas, Mark; Xue, Yali; Schnall-Levin, Michael; Petkov, Petko M.; Tyler-Smith, Chris; Maher, Eamonn R.; Trembath, Richard C.; MacArthur, Daniel G.; Wright, John; Durbin, Richard; van Heel, David A.

    2016-01-01

    Examining complete gene knockouts within a viable organism can inform on gene function. We sequenced the exomes of 3,222 British Pakistani-heritage adults with high parental relatedness, discovering 1,111 rare-variant homozygous genotypes with predicted loss of gene function (knockouts) in 781 genes. We observed 13.7% fewer than expected homozygous knockout genotypes, implying an average load of 1.6 recessive-lethal-equivalent LOF variants per adult. Linking genetic data to lifelong health records, knockouts were not associated with clinical consultation or prescription rate. In this dataset we identified a healthy PRDM9 knockout mother, and performed phased genome sequencing on her, her child and controls, which showed meiotic recombination sites localised away from PRDM9-dependent hotspots. Thus, natural LOF variants inform upon essential genetic loci, and demonstrate PRDM9 redundancy in humans. PMID:26940866

  3. Adult stem cells: simply a tool for regenerative medicine or an additional piece in the puzzle of human aging?

    PubMed

    Tollervey, James R; Lunyak, Victoria V

    2011-12-15

    Adult stem cells have taken center stage in current research related to regenerative medicine and pharmacogenomic studies seeking new therapeutic interventions. As we learn more about these cells, it is becoming apparent that the next big leap in our understanding of adult stem cell biology and adult stem cell aging will depend on the integration of approaches from various disciplines. Major advances and technological breakthroughs at the crossroad of fields such as biomaterials, genomics, epigenomics, and proteomics will enable the design of better tools to model human diseases, and warrant safe usage of adult stem cells in the clinic.

  4. Modification of the NEMA XR21-2000 cardiac phantom for testing of imaging systems used in endovascular image guided interventions

    NASA Astrophysics Data System (ADS)

    Ionita, C. N.; Dohatcu, A.; Jain, A.; Keleshis, C.; Hoffmann, K. R.; Bednarek, D. R.; Rudin, S.

    2009-02-01

    X-ray equipment testing using phantoms that mimic the specific human anatomy, morphology, and structure is a very important step in the research, development, and routine quality assurance for such equipment. Although the NEMA XR21 phantom exists for cardiac applications, there is no such standard phantom for neuro-, peripheral and cardiovascular angiographic applications. We have extended the application of the NEMA XR21-2000 phantom to evaluate neurovascular x-ray imaging systems by structuring it to be head-equivalent; two aluminum plates shaped to fit into the NEMA phantom geometry were added to a 15 cm thick section. Also, to enable digital subtraction angiography (DSA) testing, two replaceable central plates with a hollow slot were made so that various angiographic sections could be inserted into the phantom. We tested the new modified phantom using a flat panel C-arm unit dedicated for endovascular image-guided interventions. All NEMA XR21-2000 standard test sections were used in evaluations with the new "headequivalent" phantom. DSA and DA are able to be tested using two standard removable blocks having simulated arteries of various thickness and iodine concentrations (AAPM Report 15). The new phantom modifications have the benefits of enabling use of the standard NEMA phantom for angiography in both neuro- and cardio-vascular applications, with the convenience of needing only one versatile phantom for multiple applications. Additional benefits compared to using multiple phantoms are increased portability and lower cost.

  5. Thermochromic tissue-mimicking phantom for optimisation of thermal tumour ablation.

    PubMed

    Negussie, Ayele H; Partanen, Ari; Mikhail, Andrew S; Xu, Sheng; Abi-Jaoudeh, Nadine; Maruvada, Subha; Wood, Bradford J

    2016-05-01

    Purpose The purpose of this study was to (1) develop a novel tissue-mimicking thermochromic (TMTC) phantom that permanently changes colour from white to magenta upon heating above ablative temperatures, and (2) assess its utility for specific applications in evaluating thermal therapy devices. Materials and methods Polyacrylamide gel mixed with thermochromic ink was custom made to produce a TMTC phantom that changes its colour upon heating above biological ablative temperatures (> 60 °C). The thermal properties of the phantom were characterised, and compared to those of human tissue. In addition, utility of this phantom as a tool for the assessment of laser and microwave thermal ablation was examined. Results The mass density, thermal conductivity, and thermal diffusivity of the TMTC phantom were measured as 1033 ± 1.0 kg/m(3), 0.590 ± 0.015 W/m.K, and 0.145 ± 0.002 mm(2)/s, respectively, and found to be in agreement with reported values for human soft tissues. Heating the phantom with laser and microwave ablation devices produced clearly demarcated regions of permanent colour change geographically corresponding to regions with temperature elevations above 60 °C. Conclusion The TMTC phantom provides direct visualisation of ablation dynamics, including ablation volume and geometry as well as peak absolute temperatures within the treated region post-ablation. This phantom can be specifically tailored for different thermal therapy modalities, such as radiofrequency, laser, microwave, or therapeutic ultrasound ablation. Such modality-specific phantoms may enable better quality assurance, device characterisation, and ablation parameter optimisation, or optimise the study of dynamic heating parameters integral to drug device combination therapies relying upon heat.

  6. Thermochromic tissue-mimicking phantom for optimisation of thermal tumour ablation.

    PubMed

    Negussie, Ayele H; Partanen, Ari; Mikhail, Andrew S; Xu, Sheng; Abi-Jaoudeh, Nadine; Maruvada, Subha; Wood, Bradford J

    2016-05-01

    Purpose The purpose of this study was to (1) develop a novel tissue-mimicking thermochromic (TMTC) phantom that permanently changes colour from white to magenta upon heating above ablative temperatures, and (2) assess its utility for specific applications in evaluating thermal therapy devices. Materials and methods Polyacrylamide gel mixed with thermochromic ink was custom made to produce a TMTC phantom that changes its colour upon heating above biological ablative temperatures (> 60 °C). The thermal properties of the phantom were characterised, and compared to those of human tissue. In addition, utility of this phantom as a tool for the assessment of laser and microwave thermal ablation was examined. Results The mass density, thermal conductivity, and thermal diffusivity of the TMTC phantom were measured as 1033 ± 1.0 kg/m(3), 0.590 ± 0.015 W/m.K, and 0.145 ± 0.002 mm(2)/s, respectively, and found to be in agreement with reported values for human soft tissues. Heating the phantom with laser and microwave ablation devices produced clearly demarcated regions of permanent colour change geographically corresponding to regions with temperature elevations above 60 °C. Conclusion The TMTC phantom provides direct visualisation of ablation dynamics, including ablation volume and geometry as well as peak absolute temperatures within the treated region post-ablation. This phantom can be specifically tailored for different thermal therapy modalities, such as radiofrequency, laser, microwave, or therapeutic ultrasound ablation. Such modality-specific phantoms may enable better quality assurance, device characterisation, and ablation parameter optimisation, or optimise the study of dynamic heating parameters integral to drug device combination therapies relying upon heat. PMID:27099078

  7. Human tau expression reduces adult neurogenesis in a mouse model of tauopathy.

    PubMed

    Komuro, Yutaro; Xu, Guixiang; Bhaskar, Kiran; Lamb, Bruce T

    2015-06-01

    Accumulation of hyperphosphorylated and aggregated microtubule-associated protein tau (MAPT) is a central feature of a class of neurodegenerative diseases termed tauopathies. Notably, there is increasing evidence that tauopathies, including Alzheimer's disease, are also characterized by a reduction in neurogenesis, the birth of adult neurons. However, the exact relationship between hyperphosphorylation and aggregation of MAPT and neurogenic deficits remains unclear, including whether this is an early- or late-stage disease marker. In the present study, we used the genomic-based hTau mouse model of tauopathy to examine the temporal and spatial regulation of adult neurogenesis during the course of the disease. Surprisingly, hTau mice exhibited reductions in adult neurogenesis in 2 different brain regions by as early as 2 months of age, before the development of robust MAPT pathology in this model. This reduction was found to be due to reduced proliferation and not because of enhanced apoptosis in the hippocampus. At these same time points, hTau mice also exhibited altered MAPT phosphorylation with neurogenic precursors. To examine whether the effects of MAPT on neurogenesis were cell autonomous, neurospheres prepared from hTau animals were examined in vitro, revealing a growth deficit when compared with non-transgenic neurosphere cultures. Taken together, these studies provide evidence that altered adult neurogenesis is a robust and early marker of altered, cell-autonomous function of MAPT in the hTau mouse mode of tauopathy and that altered adult neurogenesis should be examined as a potential marker and therapeutic target for human tauopathies.

  8. Three-dimensional dental arch curvature in human adolescents and adults.

    PubMed

    Ferrario, V F; Sforza, C; Poggio, C E; Serrao, G; Colombo, A

    1999-04-01

    The three-dimensional arrangement of dental cusps and incisal edges in human dentitions has been reported to fit the surface of a sphere (the curve of Monson), with a radius of about 4 inches in adults. The objective of the current study was to compare the three-dimensional curvature of the mandibular dental arch in healthy permanent dentitions of young adults and adolescents. The mandibular casts of 50 adults (aged 19 to 22 years) and 20 adolescents (aged 12 to 14 years) with highly selected sound dentitions that were free from temporomandibular joint problems were obtained. The three coordinates of cusp tips excluding the third molars were digitized with a three-dimensional digitizer, and used to derive a spherical model of the curvature of the occlusal surfaces. From the best interpolating sphere, the radii of the left and right curves of Spee (quasi-sagittal plane) and of molar curve of Wilson (frontal plane) were computed. Mandibular arch size (interdental distances) was also calculated. The occlusal curvature of the mandibular arch was not significantly influenced by sex, although a significant effect of age was found (Student t, P <.005). The radii of the overall sphere, right and left curves of Spee, and curve of Wilson in the molar area were about 101 mm in adults, and about 80 mm in adolescents. Arch size was not influenced by either sex or age. The different curvatures of the occlusal plane in adolescents and adults may be explained by a progressive rotation of the major axis of the teeth moving the occlusal plane toward a more buccal position. These dental movements should be performed in a frontal plane on an anteroposterior axis located next to the dental crown.

  9. Wormholes supported by a phantom energy

    SciTech Connect

    Sushkov, Sergey

    2005-02-15

    We extend the notion of phantom energy, which is generally accepted for homogeneously distributed matter with w<-1 in the universe, on inhomogeneous spherically symmetric spacetime configurations. A spherically symmetric distribution of phantom energy is shown to be able to support the existence of static wormholes. We find an exact solution describing a static spherically symmetric wormhole with phantom energy and show that a spatial distribution of the phantom energy is mainly restricted by the vicinity of the wormhole's throat. The maximal size of the spherical region, surrounding the throat and containing the most part of the phantom energy, depends on the equation-of-state parameter w and cannot exceed some upper limit.

  10. Enceladus' 101 Geysers: Phantoms? Hardly

    NASA Astrophysics Data System (ADS)

    Porco, C.; Nimmo, F.; DiNino, D.

    2015-12-01

    The discovery by the Cassini mission of present-day geysering activity capping the southern hemisphere of Saturn's moon Enceladus (eg, Porco, C. C. et al. Science 311, 1393, 2006) and sourced within a subsurface body of liquid water (eg, Postberg, F. et al. Nature 459, 1098, 2009; Porco, C.C. et al. AJ 148, 45, 2014, hereafter PEA], laced with organic compounds (eg, Waite, J.H. et al. Science 311, 1419, 2006), has been a significant one, with far-reaching astrobiological implications. In an extensive Cassini imaging survey of the moon's south polar terrain (SPT), PEA identified 101 distinct, narrow jets of small icy particles erupting, with varying strengths, from the four major fractures crossing the SPT. A sufficient spread in stereo angles of the 107 images used in that work allowed (in some cases, many) pair-wise triangulations to be computed; precise surface locations were derived for 98 jets. Recently, it has been claimed (Spitale, J.N. et al. Nature 521, 57, 2015) that the majority of the geysers are not true discrete jets, but are "phantoms" that appear in shallow-angle views of a dense continuous curtain of material with acute bends in it. These authors also concluded that the majority of the eruptive material is not in the form of jets but in the form of fissure-style 'curtain' eruptions. We argue below the contrary, that because almost all the moon's geysers were identified by PEA using multiple images with favorable viewing geometries, the vast majority of them, and likely all, are discrete jets. Specifically, out of 98 jets, no fewer than 90 to 95 were identified with viewing geometries that preclude the appearance of phantoms. How the erupting solids (i.e., icy particles) that are seen in Cassini images are partitioned between jets and inter-jet curtains is still an open question.

  11. Characterization of diverse forms of myosin heavy chain expressed in adult human skeletal muscle.

    PubMed Central

    Saez, L; Leinwand, L A

    1986-01-01

    In an attempt to define myosin heavy chain (MHC) gene organization and expression in adult human skeletal muscle, we have isolated and characterized genomic sequences corresponding to different human sarcomeric MHC genes (1). In this report, we present the complete DNA sequence of two different adult human skeletal muscle MHC cDNA clones, one of which encodes the entire light meromyosin (LMM) segment of MHC and represents the longest described MHC cDNA sequence. Additionally, both clones provide new sequence data from a 228 amino acid segment of the MHC tail for which no protein or DNA sequence has been previously available. One clone encodes a "fast" form of skeletal muscle MHC while the other clone most closely resembles a MHC form described in rat cardiac ventricles. We show that the 3' untranslated region of skeletal MHC cDNAs are homologous from widely separated species as are cardiac MHC cDNAs. However, there is no homology between the 3' untranslated region of cardiac and skeletal muscle MHCs. Isotype-specific preservation of MHC 3' untranslated sequences during evolution suggests a functional role for these regions. Images PMID:2421254

  12. Development of 1-year-old computational phantom and calculation of organ doses during CT scans using Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Pan, Yuxi; Qiu, Rui; Gao, Linfeng; Ge, Chaoyong; Zheng, Junzheng; Xie, Wenzhang; Li, Junli

    2014-09-01

    With the rapidly growing number of CT examinations, the consequential radiation risk has aroused more and more attention. The average dose in each organ during CT scans can only be obtained by using Monte Carlo simulation with computational phantoms. Since children tend to have higher radiation sensitivity than adults, the radiation dose of pediatric CT examinations requires special attention and needs to be assessed accurately. So far, studies on organ doses from CT exposures for pediatric patients are still limited. In this work, a 1-year-old computational phantom was constructed. The body contour was obtained from the CT images of a 1-year-old physical phantom and the internal organs were deformed from an existing Chinese reference adult phantom. To ensure the organ locations in the 1-year-old computational phantom were consistent with those of the physical phantom, the organ locations in 1-year-old computational phantom were manually adjusted one by one, and the organ masses were adjusted to the corresponding Chinese reference values. Moreover, a CT scanner model was developed using the Monte Carlo technique and the 1-year-old computational phantom was applied to estimate organ doses derived from simulated CT exposures. As a result, a database including doses to 36 organs and tissues from 47 single axial scans was built. It has been verified by calculation that doses of axial scans are close to those of helical scans; therefore, this database could be applied to helical scans as well. Organ doses were calculated using the database and compared with those obtained from the measurements made in the physical phantom for helical scans. The differences between simulation and measurement were less than 25% for all organs. The result shows that the 1-year-old phantom developed in this work can be used to calculate organ doses in CT exposures, and the dose database provides a method for the estimation of 1-year-old patient doses in a variety of CT examinations.

  13. Development of 1-year-old computational phantom and calculation of organ doses during CT scans using Monte Carlo simulation.

    PubMed

    Pan, Yuxi; Qiu, Rui; Gao, Linfeng; Ge, Chaoyong; Zheng, Junzheng; Xie, Wenzhang; Li, Junli

    2014-09-21

    With the rapidly growing number of CT examinations, the consequential radiation risk has aroused more and more attention. The average dose in each organ during CT scans can only be obtained by using Monte Carlo simulation with computational phantoms. Since children tend to have higher radiation sensitivity than adults, the radiation dose of pediatric CT examinations requires special attention and needs to be assessed accurately. So far, studies on organ doses from CT exposures for pediatric patients are still limited. In this work, a 1-year-old computational phantom was constructed. The body contour was obtained from the CT images of a 1-year-old physical phantom and the internal organs were deformed from an existing Chinese reference adult phantom. To ensure the organ locations in the 1-year-old computational phantom were consistent with those of the physical phantom, the organ locations in 1-year-old computational phantom were manually adjusted one by one, and the organ masses were adjusted to the corresponding Chinese reference values. Moreover, a CT scanner model was developed using the Monte Carlo technique and the 1-year-old computational phantom was applied to estimate organ doses derived from simulated CT exposures. As a result, a database including doses to 36 organs and tissues from 47 single axial scans was built. It has been verified by calculation that doses of axial scans are close to those of helical scans; therefore, this database could be applied to helical scans as well. Organ doses were calculated using the database and compared with those obtained from the measurements made in the physical phantom for helical scans. The differences between simulation and measurement were less than 25% for all organs. The result shows that the 1-year-old phantom developed in this work can be used to calculate organ doses in CT exposures, and the dose database provides a method for the estimation of 1-year-old patient doses in a variety of CT examinations.

  14. Phantom dosimetry and image quality of i-CAT FLX cone-beam computed tomography

    PubMed Central

    Ludlow, John B.; Walker, Cameron

    2013-01-01

    Introduction Increasing use of cone-beam computed tomography in orthodontics has been coupled with heightened concern with the long-term risks of x-ray exposure in orthodontic populations. An industry response to this has been to offer low-exposure alternative scanning options in newer cone-beam computed tomography models. Methods Effective doses resulting from various combinations of field size, and field location comparing child and adult anthropomorphic phantoms using the recently introduced i-CAT FLX cone-beam computed tomography unit were measured with Optical Stimulated Dosimetry using previously validated protocols. Scan protocols included High Resolution (360° rotation, 600 image frames, 120 kVp, 5 mA, 7.4 sec), Standard (360°, 300 frames, 120 kVp, 5 mA, 3.7 sec), QuickScan (180°, 160 frames, 120 kVp, 5 mA, 2 sec) and QuickScan+ (180°, 160 frames, 90 kVp, 3 mA, 2 sec). Contrast-to-noise ratio (CNR) was calculated as a quantitative measure of image quality for the various exposure options using the QUART DVT phantom. Results Child phantom doses were on average 36% greater than Adult phantom doses. QuickScan+ protocols resulted in significantly lower doses than Standard protocols for child (p=0.0167) and adult (p=0.0055) phantoms. 13×16 cm cephalometric fields of view ranged from 11–85 μSv in the adult phantom and 18–120 μSv in the child for QuickScan+ and Standard protocols respectively. CNR was reduced by approximately 2/3rds comparing QuickScan+ to Standard exposure parameters. Conclusions QuickScan+ effective doses are comparable to conventional panoramic examinations. Significant dose reductions are accompanied by significant reductions in image quality. However, this trade-off may be acceptable for certain diagnostic tasks such as interim assessment of treatment results. PMID:24286904

  15. Cortical surface area and cortical thickness in the precuneus of adult humans.

    PubMed

    Bruner, E; Román, F J; de la Cuétara, J M; Martin-Loeches, M; Colom, R

    2015-02-12

    The precuneus has received considerable attention in the last decade, because of its cognitive functions, its role as a central node of the brain networks, and its involvement in neurodegenerative processes. Paleoneurological studies suggested that form changes in the deep parietal areas represent a major character associated with the origin of the modern human brain morphology. A recent neuroanatomical survey based on shape analysis suggests that the proportions of the precuneus are also a determinant source of overall brain geometrical differences among adult individuals, influencing the brain spatial organization. Here, we evaluate the variation of cortical thickness and cortical surface area of the precuneus in a sample of adult humans, and their relation with geometry and cognition. Precuneal thickness and surface area are not correlated. There is a marked individual variation. The right precuneus is thinner and larger than the left one, but there are relevant fluctuating asymmetries, with only a modest correlation between the hemispheres. Males have a thicker cortex but differences in cortical area are not significant between sexes. The surface area of the precuneus shows a positive allometry with the brain surface area, although the correlation is modest. The dilation/contraction of the precuneus, described as a major factor of variability within adult humans, is associated with absolute increase/decrease of its surface, but not with variation in thickness. Precuneal thickness, precuneal surface area and precuneal morphology are not correlated with psychological factors such as intelligence, working memory, attention control, and processing speed, stressing further possible roles of this area in supporting default mode functions. Beyond gross morphology, the processes underlying the large phenotypic variation of the precuneus must be further investigated through specific cellular analyses, aimed at considering differences in cellular size, density

  16. Understanding and Managing Learning Disabilities in Adults. Professional Practices in Adult Education and Human Resource Development Series.

    ERIC Educational Resources Information Center

    Jordan, Dale R.

    This book reviews learning disabilities (LD) in adults and makes suggestions for helping adults cope with these disabilities. Each chapter covers a type of learning disability or related syndrome or explains characteristics of the brain. Chapter 1 explains several types of specific learning disabilities that make classroom performance difficult…

  17. Compact and extended objects from self-interacting phantom fields

    NASA Astrophysics Data System (ADS)

    Dzhunushaliev, Vladimir; Folomeev, Vladimir; Makhmudov, Arislan; Urazalina, Ainur; Singleton, Douglas; Scott, John

    2016-07-01

    In this work, we investigate localized and extended objects for gravitating, self-interacting phantom fields. The phantom fields come from two scalar fields with a "wrong-sign" (negative) kinetic energy term in the Lagrangian. This study covers several solutions supported by these phantom fields: phantom balls, traversable wormholes, phantom cosmic strings, and "phantom" domain walls. These four systems are solved numerically, and we try to draw out general, interesting features in each case.

  18. Development of a Physiologically Based Model to Describe the Pharmacokinetics of Methylphenidate in Juvenile and Adult Humans and Nonhuman Primates

    PubMed Central

    Yang, Xiaoxia; Morris, Suzanne M.; Gearhart, Jeffery M.; Ruark, Christopher D.; Paule, Merle G.; Slikker, William; Mattison, Donald R.; Vitiello, Benedetto; Twaddle, Nathan C.; Doerge, Daniel R.; Young, John F.; Fisher, Jeffrey W.

    2014-01-01

    The widespread usage of methylphenidate (MPH) in the pediatric population has received considerable attention due to its potential effect on child development. For the first time a physiologically based pharmacokinetic (PBPK) model has been developed in juvenile and adult humans and nonhuman primates to quantitatively evaluate species- and age-dependent enantiomer specific pharmacokinetics of MPH and its primary metabolite ritalinic acid. The PBPK model was first calibrated in adult humans using in vitro enzyme kinetic data of MPH enantiomers, together with plasma and urine pharmacokinetic data with MPH in adult humans. Metabolism of MPH in the small intestine was assumed to account for the low oral bioavailability of MPH. Due to lack of information, model development for children and juvenile and adult nonhuman primates primarily relied on intra- and interspecies extrapolation using allometric scaling. The juvenile monkeys appear to metabolize MPH more rapidly than adult monkeys and humans, both adults and children. Model prediction performance is comparable between juvenile monkeys and children, with average root mean squared error values of 4.1 and 2.1, providing scientific basis for interspecies extrapolation of toxicity findings. Model estimated human equivalent doses in children that achieve similar internal dose metrics to those associated with pubertal delays in juvenile monkeys were found to be close to the therapeutic doses of MPH used in pediatric patients. This computational analysis suggests that continued pharmacovigilance assessment is prudent for the safe use of MPH. PMID:25184666

  19. Gastrointestinal absorption of plutonium, uranium and neptunium in fed and fasted adult baboons: Application to humans

    SciTech Connect

    Bhattacharyya, M.H.; Larsen, R.P.; Oldham, R.D.; Moretti, E.S. ); Cohen, N.; Ralston, L.G.; Ayres, L. )

    1992-03-01

    Gastrointestinal (GI) absorption values of plutonium, uranium, and neptunium were determined in fed and fasted adult baboons. A dual isotope method of determining GI absorption, which does not require animal sacrifice, was validated and shown to compare well with the sacrifice method (summation of oral isotope in urine with that in tissues at sacrifice). For all three elements, mean GI absorption values were significantly high (5- to 50-fold) in 24-hour (h)-fasted animals than in fed animals, and GI absorption values for baboons agreed well with those for humans.

  20. New VHP-Female v. 2.0 full-body computational phantom and its performance metrics using FEM simulator ANSYS HFSS.

    PubMed

    Yanamadala, Janakinadh; Noetscher, Gregory M; Rathi, Vishal K; Maliye, Saili; Win, Htay A; Tran, Anh L; Jackson, Xavier J; Htet, Aung T; Kozlov, Mikhail; Nazarian, Ara; Louie, Sara; Makarov, Sergey N

    2015-01-01

    Simulation of the electromagnetic response of the human body relies heavily upon efficient computational models or phantoms. The first objective of this paper is to present a new platform-independent full-body electromagnetic computational model (computational phantom), the Visible Human Project(®) (VHP)-Female v. 2.0 and to describe its distinct features. The second objective is to report phantom simulation performance metrics using the commercial FEM electromagnetic solver ANSYS HFSS.

  1. The impact of calibration phantom errors on dual-energy digital mammography

    PubMed Central

    Mou, Xuanqin; Chen, Xi; Sun, Lijun; Yu, Hengyong; Ji, Zhen; Zhang, Lei

    2010-01-01

    Microcalcification is one of the earliest and main indicators of breast cancer. Because dual-energy digital mammography could suppress the contrast between the adipose and glandular tissues of the breast, it is considered a promising technique that will improve the detection of microcalcification. In dual-energy digital mammography, the imaged object is a human breast, while in calibration measurements only the phantoms of breast tissue equivalent materials are available. Consequently, the differences between phantoms and breast tissues will lead to calibration phantom errors. Based on the dual-energy imaging model, formulae of calibration phantom errors are derived in this paper. Then, this type of error is quantitatively analyzed using publicly available data and compared with other types of error. The results demonstrate that the calibration phantom error is large and dominant in dual-energy mammography, seriously decreasing calculation precision. Further investigations on the physical meaning of calibration phantom error reveal that the imaged objects with the same glandular ratio have identical calibration phantom error. Finally, an error correction method is proposed based on our findings. PMID:18936520

  2. Tissue equivalency of phantom materials for neutron dosimetry in proton therapy

    SciTech Connect

    Dowdell, Stephen; Clasie, Ben; Wroe, Andrew; Guatelli, Susanna; Metcalfe, Peter; Schulte, Reinhard; Rosenfeld, Anatoly

    2009-12-15

    Purpose: Previous Monte Carlo and experimental studies involving secondary neutrons in proton therapy have employed a number of phantom materials that are designed to represent human tissue. In this study, the authors determined the suitability of common phantom materials for dosimetry of secondary neutrons, specifically for pediatric and intracranial proton therapy treatments. Methods: This was achieved through comparison of the absorbed dose and dose equivalent from neutrons generated within the phantom materials and various ICRP tissues. The phantom materials chosen for comparison were Lucite, liquid water, solid water, and A150 tissue equivalent plastic. These phantom materials were compared to brain, muscle, and adipose tissues. Results: The magnitude of the doses observed were smaller than those reported in previous experimental and Monte Carlo studies, which incorporated neutrons generated in the treatment head. The results show that for both neutron absorbed dose and dose equivalent, no single phantom material gives agreement with tissue within 5% at all the points considered. Solid water gave the smallest mean variation with the tissues out of field where neutrons are the primary contributor to the total dose. Conclusions: Of the phantom materials considered, solid water shows best agreement with tissues out of field.

  3. Quality assurance for ultrasound scanners using a durable tissue-mimicking phantom and radial MTF

    NASA Astrophysics Data System (ADS)

    Kaar, Marcus; Semturs, Friedrich; Figl, Michael; Hoffmann, Rainer; Hummel, Johann

    2014-03-01

    For the use in routine technical quality assurance (TQA) we developed a tissue-mimicking phantom and an evaluation algorithm. Key properties of US phantom materials are sound velocity and acoustic attenuation. For daily clinical use the material also has to be nontoxic, durable and easy in handling and maintenance. The base material of our phantom is Poly(vinyl alcohol) (PVA), a synthetic polymer. By freezing the phantom body during the production process, it changes its sound velocity to closely match the one of the human body. The phantom's base form is a cuboid containing a large anechoic cylindric target. In routine QA it is required to gain comparable and reproducible results from a single image. To determine spatial resolution of phantom images, we calculate a modulation transfer function (MTF). We developed an algorithm, that calculates a radial MTF from a circular structure representing spatial resolution averaged across all directions. For evaluation of the algorithm, we created a set of synthetic images. A comparison of the results from a traditional slanted edge algorithm and our solution showed a close correlation. The US phantom was imaged with a commercial US-scanner at different sound frequencies. The computed MTFs of higher frequency images show higher transfer percentages in all spatial frequencies than the MTFs of lower frequency images. The results suggest that the proposed method produces clear statements about the spatial resolution of evaluated imaging devices. We therefore consider the method as suitable for application in technical quality assurance of diagnostic ultrasound scanners.

  4. A statistically defined anthropomorphic software breast phantom

    SciTech Connect

    Lau, Beverly A.; Reiser, Ingrid; Nishikawa, Robert M.; Bakic, Predrag R.

    2012-06-15

    Purpose: Digital anthropomorphic breast phantoms have emerged in the past decade because of recent advances in 3D breast x-ray imaging techniques. Computer phantoms in the literature have incorporated power-law noise to represent glandular tissue and branching structures to represent linear components such as ducts. When power-law noise is added to those phantoms in one piece, the simulated fibroglandular tissue is distributed randomly throughout the breast, resulting in dense tissue placement that may not be observed in a real breast. The authors describe a method for enhancing an existing digital anthropomorphic breast phantom by adding binarized power-law noise to a limited area of the breast. Methods: Phantoms with (0.5 mm){sup 3} voxel size were generated using software developed by Bakic et al. Between 0% and 40% of adipose compartments in each phantom were replaced with binarized power-law noise ({beta} = 3.0) ranging from 0.1 to 0.6 volumetric glandular fraction. The phantoms were compressed to 7.5 cm thickness, then blurred using a 3 Multiplication-Sign 3 boxcar kernel and up-sampled to (0.1 mm){sup 3} voxel size using trilinear interpolation. Following interpolation, the phantoms were adjusted for volumetric glandular fraction using global thresholding. Monoenergetic phantom projections were created, including quantum noise and simulated detector blur. Texture was quantified in the simulated projections using power-spectrum analysis to estimate the power-law exponent {beta} from 25.6 Multiplication-Sign 25.6 mm{sup 2} regions of interest. Results: Phantoms were generated with total volumetric glandular fraction ranging from 3% to 24%. Values for {beta} (averaged per projection view) were found to be between 2.67 and 3.73. Thus, the range of textures of the simulated breasts covers the textures observed in clinical images. Conclusions: Using these new techniques, digital anthropomorphic breast phantoms can be generated with a variety of glandular fractions

  5. Effective dose evaluation for BNCT brain tumor treatment based on voxel phantoms.

    PubMed

    Wang, Jeng-Ning; Lee, Kuo-Wei; Jiang, Shiang-Huei

    2014-06-01

    For BNCT treatments, in addition to tumor target doses, non-negligible doses will result in all the remaining organs of the body. This work aims to evaluate the effective dose as well as the average absorbed doses of each of organs of patients with brain tumor treated in the BNCT epithermal neutron beam at THOR. The effective doses were evaluated according to the definitions of ICRP Publications 60 and 103 for the reference male and female computational phantoms developed in ICRP Publication 110 by using the MCNP5 Monte Carlo code with the THOR-Y09 beam source. The effective dose acquired in this work was compared with the results of our previous work calculated for an adult hermaphrodite mathematical phantom. It was found that the effective dose for the female voxel phantom is larger than that for the male voxel phantom by a factor of 1.2-1.5 and the effective dose for the voxel phantom is larger than that for the mathematical phantom by a factor of 1.3-1.6. For a typical brain tumor BNCT, the effective dose was calculated to be 1.51Sv and the average absorbed dose for eye lenses was 1.07Gy.

  6. First all-solid pediatric phantom for dual X-ray absorptiometry measurements in infants.

    PubMed

    Picaud, Jean-Charles; Duboeuf, François; Vey-Marty, Vey; Delams, Pierre; Claris, Oliver; Salle, Bernard-Louis; Rigo, Jacques

    2003-01-01

    Manufacturer-supplied lumbar spine phantoms are normally used for quality control of dual X-ray absorptiometry (DXA) instruments. Presently, there is no pediatric phantom for whole-body mineralization and softtissue composition DXA measurements. We designed blocks of acrylic (for fat mass), polyvinyl chloride (for lean mass), and aluminum (for bone mass) whose combination provides five whole-body phantoms ("Inphants") that mimic body weight and composition during the first year of life and help solve problems that require repeated scans in stable conditions. Inphants were scanned using an Hologic QDR 2000. Comparisons were made between values obtained with and without the table pad, using infant software. Then we compared data obtained using infant and adult softwares successively in the same phantoms. The table pad significantly influenced DXA measurements. We observed significant differences in fat mass (p = 0.04) and lean mass (p = 0.03) with the smaller Inphant (3 kg) and in bone mineral content (BMC) (p = 0.02) with the larger Inphant (13 kg). BMC was three to five times lower with adult than with infant software. Adult software yielded systematically significantly lower fat masses but higher lean masses than infant software. Because there was no overlap with larger Inphants, we calculated conversion formulae between values of infant and adult software. The results suggest guidelines for scan acquisition and analysis in young subjects. PMID:12665698

  7. Biomimetic phantom for cardiac diffusion MRI

    PubMed Central

    Teh, Irvin; Zhou, Feng‐Lei; Hubbard Cristinacce, Penny L.; Parker, Geoffrey J.M.

    2015-01-01

    Purpose Diffusion magnetic resonance imaging (MRI) is increasingly used to characterize cardiac tissue microstructure, necessitating the use of physiologically relevant phantoms for methods development. Existing phantoms are generally simplistic and mostly simulate diffusion in the brain. Thus, there is a need for phantoms mimicking diffusion in cardiac tissue. Materials and Methods A biomimetic phantom composed of hollow microfibers generated using co‐electrospinning was developed to mimic myocardial diffusion properties and fiber and sheet orientations. Diffusion tensor imaging was carried out at monthly intervals over 4 months at 9.4T. 3D fiber tracking was performed using the phantom and compared with fiber tracking in an ex vivo rat heart. Results The mean apparent diffusion coefficient and fractional anisotropy of the phantom remained stable over the 4‐month period, with mean values of 7.53 ± 0.16 × 10‐4 mm2/s and 0.388 ± 0.007, respectively. Fiber tracking of the 1st and 3rd eigenvectors generated analogous results to the fiber and sheet‐normal direction respectively, found in the left ventricular myocardium. Conclusion A biomimetic phantom simulating diffusion in the heart was designed and built. This could aid development and validation of novel diffusion MRI methods for investigating cardiac microstructure, decrease the number of animals and patients needed for methods development, and improve quality control in longitudinal and multicenter cardiac diffusion MRI studies. J. MAGN. RESON. IMAGING 2016;43:594–600. PMID:26213152

  8. Galactic dark matter in the phantom field

    NASA Astrophysics Data System (ADS)

    Li, Ming-Hsun; Yang, Kwei-Chou

    2012-12-01

    We investigate the possibility that the galactic dark matter exists in a scenario where the phantom field is responsible for the dark energy. We obtain the statically and spherically approximate solution for this kind of galaxy system with a supermassive black hole at its center. The solution of the metric functions is satisfied with gtt=-grr-1. Constrained by the observation of the rotational stars moving in circular orbits with nearly constant tangential speed in a spiral galaxy, the background of the phantom field which is spatially inhomogeneous has an exponential potential. To avoid the well-known quantum instability of the vacuum at high frequencies, the phantom field defined in an effective theory is valid only at low energies. Under this assumption, we further investigate the following properties. The absorption cross section of the low-energy S-wave excitations of the phantom field into the central black hole is shown to be the horizontal area of the central black hole. Because the infalling phantom particles have a total negative energy, the accretion of the phantom energy is related to the decrease of the black hole mass, which is estimated to be much less than a solar mass in the lifetime of the Universe. Using a simple model with the cold dark matter very weakly coupled to the “low-frequency” phantom particles that are generated from the background, we show that these two densities can be quasistable in the galaxy.

  9. Partial volume simulation in software breast phantoms

    NASA Astrophysics Data System (ADS)

    Chen, Feiyu; Pokrajac, David; Shi, Xiquan; Liu, Fengshan; Maidment, Andrew D. A.; Bakic, Predrag R.

    2012-03-01

    A modification to our previous simulation of breast anatomy is proposed, in order to improve the quality of simulated projections generated using software breast phantoms. Anthropomorphic software breast phantoms have been used for quantitative validation of breast imaging systems. Previously, we developed a novel algorithm for breast anatomy simulation, which did not account for the partial volume (PV) of various tissues in a voxel; instead, each phantom voxel was assumed to contain single tissue type. As a result, phantom projection images displayed notable artifacts near the borders between regions of different materials, particularly at the skin-air boundary. These artifacts diminished the realism of phantom images. One solution is to simulate smaller voxels. Reducing voxel size, however, extends the phantom generation time and increases memory requirements. We achieved an improvement in image quality without reducing voxel size by the simulation of PV in voxels containing more than one simulated tissue type. The linear x-ray attenuation coefficient of each voxel is calculated by combining attenuation coefficients proportional to the voxel subvolumes occupied by the various tissues. A local planar approximation of the boundary surface is employed, and the skin volume in each voxel is computed by decomposition into simple geometric shapes. An efficient encoding scheme is proposed for the type and proportion of simulated tissues in each voxel. We illustrate the proposed methodology on phantom slices and simulated mammographic projections. Our results show that the PV simulation has improved image quality by reducing quantization artifacts.

  10. Design and construction of a brain phantom to simulate neonatal MR images.

    PubMed

    Kazemi, Kamran; Moghaddam, Hamid Abrishami; Grebe, Reinhard; Gondry-Jouet, Catherine; Wallois, Fabrice

    2011-04-01

    This paper presents the design and construction of a 3D digital neonatal neurocranial phantom and its application for the simulation of brain magnetic resonance (MR) images. Commonly used digital brain phantoms (e.g. BrainWeb) are based on the adult brain. With the growing interest in computer-aided methods for neonatal MR image processing, there is a growing demand a digital phantom and brain MR image simulator especially for the neonatal brains. This is due to the pronounced differences between adult and neonatal brains not only in terms of size but also, more importantly, in terms of geometrical proportions and the need to subdivide white matter into two different tissue types in neonates. Therefore the neonatal brain phantom created in the here presented work consists of 9 different tissue types: skin, fat, muscle, skull, dura mater, gray matter, myelinated white matter, nonmyelinated white matter and cerebrospinal fluid. Each voxel has a vector consisting of 9 components, one for each of these nine tissue types. This digital phantom can be used to map simulated magnetic resonance signal intensities resulting in simulated MR images of the newborns head. These images with controlled degradation of the image data present a representative, reproducible data set ideal for development and evaluation of neonatal MRI analysis methods, e.g. segmentation and registration algorithms.

  11. Image guided constitutive modeling of the silicone brain phantom

    NASA Astrophysics Data System (ADS)

    Puzrin, Alexander; Skrinjar, Oskar; Ozan, Cem; Kim, Sihyun; Mukundan, Srinivasan

    2005-04-01

    The goal of this work is to develop reliable constitutive models of the mechanical behavior of the in-vivo human brain tissue for applications in neurosurgery. We propose to define the mechanical properties of the brain tissue in-vivo, by taking the global MR or CT images of a brain response to ventriculostomy - the relief of the elevated intracranial pressure. 3D image analysis translates these images into displacement fields, which by using inverse analysis allow for the constitutive models of the brain tissue to be developed. We term this approach Image Guided Constitutive Modeling (IGCM). The presented paper demonstrates performance of the IGCM in the controlled environment: on the silicone brain phantoms closely simulating the in-vivo brain geometry, mechanical properties and boundary conditions. The phantom of the left hemisphere of human brain was cast using silicon gel. An inflatable rubber membrane was placed inside the phantom to model the lateral ventricle. The experiments were carried out in a specially designed setup in a CT scanner with submillimeter isotropic voxels. The non-communicative hydrocephalus and ventriculostomy were simulated by consequently inflating and deflating the internal rubber membrane. The obtained images were analyzed to derive displacement fields, meshed, and incorporated into ABAQUS. The subsequent Inverse Finite Element Analysis (based on Levenberg-Marquardt algorithm) allowed for optimization of the parameters of the Mooney-Rivlin non-linear elastic model for the phantom material. The calculated mechanical properties were consistent with those obtained from the element tests, providing justification for the future application of the IGCM to in-vivo brain tissue.

  12. Long-term culture of genome-stable bipotent stem cells from adult human liver.

    PubMed

    Huch, Meritxell; Gehart, Helmuth; van Boxtel, Ruben; Hamer, Karien; Blokzijl, Francis; Verstegen, Monique M A; Ellis, Ewa; van Wenum, Martien; Fuchs, Sabine A; de Ligt, Joep; van de Wetering, Marc; Sasaki, Nobuo; Boers, Susanne J; Kemperman, Hans; de Jonge, Jeroen; Ijzermans, Jan N M; Nieuwenhuis, Edward E S; Hoekstra, Ruurdtje; Strom, Stephen; Vries, Robert R G; van der Laan, Luc J W; Cuppen, Edwin; Clevers, Hans

    2015-01-15

    Despite the enormous replication potential of the human liver, there are currently no culture systems available that sustain hepatocyte replication and/or function in vitro. We have shown previously that single mouse Lgr5+ liver stem cells can be expanded as epithelial organoids in vitro and can be differentiated into functional hepatocytes in vitro and in vivo. We now describe conditions allowing long-term expansion of adult bile duct-derived bipotent progenitor cells from human liver. The expanded cells are highly stable at the chromosome and structural level, while single base changes occur at very low rates. The cells can readily be converted into functional hepatocytes in vitro and upon transplantation in vivo. Organoids from α1-antitrypsin deficiency and Alagille syndrome patients mirror the in vivo pathology. Clonal long-term expansion of primary adult liver stem cells opens up experimental avenues for disease modeling, toxicology studies, regenerative medicine, and gene therapy. PMID:25533785

  13. Learning new color names produces rapid increase in gray matter in the intact adult human cortex

    PubMed Central

    Kwok, Veronica; Niu, Zhendong; Kay, Paul; Zhou, Ke; Mo, Lei; Jin, Zhen; So, Kwok-Fai; Tan, Li Hai

    2011-01-01

    The human brain has been shown to exhibit changes in the volume and density of gray matter as a result of training over periods of several weeks or longer. We show that these changes can be induced much faster by using a training method that is claimed to simulate the rapid learning of word meanings by children. Using whole-brain magnetic resonance imaging (MRI) we show that learning newly defined and named subcategories of the universal categories green and blue in a period of 2 h increases the volume of gray matter in V2/3 of the left visual cortex, a region known to mediate color vision. This pattern of findings demonstrates that the anatomical structure of the adult human brain can change very quickly, specifically during the acquisition of new, named categories. Also, prior behavioral and neuroimaging research has shown that differences between languages in the boundaries of named color categories influence the categorical perception of color, as assessed by judgments of relative similarity, by response time in alternative forced-choice tasks, and by visual search. Moreover, further behavioral studies (visual search) and brain imaging studies have suggested strongly that the categorical effect of language on color processing is left-lateralized, i.e., mediated by activity in the left cerebral hemisphere in adults (hence “lateralized Whorfian” effects). The present results appear to provide a structural basis in the brain for the behavioral and neurophysiologically observed indices of these Whorfian effects on color processing. PMID:21464316

  14. Adult Human Nasal Mesenchymal-Like Stem Cells Restore Cochlear Spiral Ganglion Neurons After Experimental Lesion

    PubMed Central

    Bas, Esperanza; Van De Water, Thomas R.; Lumbreras, Vicente; Rajguru, Suhrud; Goss, Garrett; Hare, Joshua M.

    2014-01-01

    A loss of sensory hair cells or spiral ganglion neurons from the inner ear causes deafness, affecting millions of people. Currently, there is no effective therapy to repair the inner ear sensory structures in humans. Cochlear implantation can restore input, but only if auditory neurons remain intact. Efforts to develop stem cell-based treatments for deafness have demonstrated progress, most notably utilizing embryonic-derived cells. In an effort to bypass limitations of embryonic or induced pluripotent stem cells that may impede the translation to clinical applications, we sought to utilize an alternative cell source. Here, we show that adult human mesenchymal-like stem cells (MSCs) obtained from nasal tissue can repair spiral ganglion loss in experimentally lesioned cochlear cultures from neonatal rats. Stem cells engraft into gentamicin-lesioned organotypic cultures and orchestrate the restoration of the spiral ganglion neuronal population, involving both direct neuronal differentiation and secondary effects on endogenous cells. As a physiologic assay, nasal MSC-derived cells engrafted into lesioned spiral ganglia demonstrate responses to infrared laser stimulus that are consistent with those typical of excitable cells. The addition of a pharmacologic activator of the canonical Wnt/β-catenin pathway concurrent with stem cell treatment promoted robust neuronal differentiation. The availability of an effective adult autologous cell source for inner ear tissue repair should contribute to efforts to translate cell-based strategies to the clinic. PMID:24172073

  15. Long-Term Culture of Genome-Stable Bipotent Stem Cells from Adult Human Liver

    PubMed Central

    Huch, Meritxell; Gehart, Helmuth; van Boxtel, Ruben; Hamer, Karien; Blokzijl, Francis; Verstegen, Monique M.A.; Ellis, Ewa; van Wenum, Martien; Fuchs, Sabine A.; de Ligt, Joep; van de Wetering, Marc; Sasaki, Nobuo; Boers, Susanne J.; Kemperman, Hans; de Jonge, Jeroen; Ijzermans, Jan N.M.; Nieuwenhuis, Edward E.S.; Hoekstra, Ruurdtje; Strom, Stephen; Vries, Robert R.G.; van der Laan, Luc J.W.; Cuppen, Edwin; Clevers, Hans

    2015-01-01

    Summary Despite the enormous replication potential of the human liver, there are currently no culture systems available that sustain hepatocyte replication and/or function in vitro. We have shown previously that single mouse Lgr5+ liver stem cells can be expanded as epithelial organoids in vitro and can be differentiated into functional hepatocytes in vitro and in vivo. We now describe conditions allowing long-term expansion of adult bile duct-derived bipotent progenitor cells from human liver. The expanded cells are highly stable at the chromosome and structural level, while single base changes occur at very low rates. The cells can readily be converted into functional hepatocytes in vitro and upon transplantation in vivo. Organoids from α1-antitrypsin deficiency and Alagille syndrome patients mirror the in vivo pathology. Clonal long-term expansion of primary adult liver stem cells opens up experimental avenues for disease modeling, toxicology studies, regenerative medicine, and gene therapy. PMID:25533785

  16. Morphologic characteristics of processes of nucleus pulposus cells in adult human intervertebral disc

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoyun; Wu, Xinghuo; Hui, Liu; Xu, Weihua; Liu, Xianze; Yang, Shuhua

    2008-12-01

    To explore morphologic characterizatics of cellular processes from adult human nucleus pulposus cells, the nucleus pulposus of adult human intervertebral disc were obtained from 8 patients (Thompson's grade I~II) and then the tissues specimens were carried out by frozen section and electron microscopic section as well as cell isolation and cultured, processes of nucleus pulposus cells were examined using light microscopy, laser scanning confocal microscopy and transmission electron microscopy. When examined at both the confocal and electron microscope level, all the cells possessed the processes and adjacent nucleus pulposus cells processes possessed a gap junction. But elongated and round cells can be examined when NP cells were monolayer cultured. The rate of elongated cells to round cells is 2.3 to 1. The elongated cells protrude along with the long axis of cell body without second processes. Dendritic processes of round cells protrude to all directions from the cell body with multiple-level processes. Processes are one of the morphologic characteristics of intervertebral disc cells which are different from articular cartilage chondrocytes. The research on processes functions will be helpful to understand pathomechanism of intervertebral disc degradation and open a new approach for cytobiology treatment of the intervertebral disc diseases.

  17. New ANSI standard for thyroid phantom

    SciTech Connect

    Mallett, Michael W.; Bolch, Wesley E.; Fulmer, Philip C.; Jue, Tracy M.; McCurdy, David E.; Pillay, Mike; Xu, X. George

    2015-08-01

    Here, a new ANSI standard titled “Thyroid Phantom Used in Occupational Monitoring” (Health Physics Society 2014) has been published. The standard establishes the criteria for acceptable design, fabrication, or modeling of a phantom suitable for calibrating in vivo monitoring systems to measure photon-emitting radionuclides deposited in the thyroid. The current thyroid phantom standard was drafted in 1973 (ANSI N44.3-1973), last reviewed in 1984, and a revision of the standard to cover a more modern approach was deemed warranted.

  18. Computer analysis of mammography phantom images (CAMPI)

    NASA Astrophysics Data System (ADS)

    Chakraborty, Dev P.

    1997-05-01

    Computer analysis of mammography phantom images (CAMPI) is a method for objective and precise measurements of phantom image quality in mammography. This investigation applied CAMPI methodology to the Fischer Mammotest Stereotactic Digital Biopsy machine. Images of an American College of Radiology phantom centered on the largest two microcalcification groups were obtained on this machine under a variety of x-ray conditions. Analyses of the images revealed that the precise behavior of the CAMPI measures could be understood from basic imaging physics principles. We conclude that CAMPI is sensitive to subtle image quality changes and can perform accurate evaluations of images, especially of directly acquired digital images.

  19. Human amniotic epithelial cells are reprogrammed more efficiently by induced pluripotency than adult fibroblasts.

    PubMed

    Easley, Charles A; Miki, Toshio; Castro, Carlos A; Ozolek, John A; Minervini, Crescenzio F; Ben-Yehudah, Ahmi; Schatten, Gerald P

    2012-06-01

    Cellular reprogramming from adult somatic cells into an embryonic cell-like state, termed induced pluripotency, has been achieved in several cell types. However, the ability to reprogram human amniotic epithelial cells (hAECs), an abundant cell source derived from discarded placental tissue, has only recently been investigated. Here we show that not only are hAECs easily reprogrammed into induced pluripotent stem cells (AE-iPSCs), but hAECs reprogram faster and more efficiently than adult and neonatal somatic dermal fibroblasts. Furthermore, AE-iPSCs express higher levels of NANOG and OCT4 compared to human foreskin fibroblast iPSCs (HFF1-iPSCs) and express decreased levels of genes associated with differentiation, including NEUROD1 and SOX17, markers of neuronal differentiation. To elucidate the mechanism behind the higher reprogramming efficiency of hAECs, we analyzed global DNA methylation, global histone acetylation, and the mitochondrial DNA A3243G point mutation. Whereas hAECs show no differences in global histone acetylation or mitochondrial point mutation accumulation compared to adult and neonatal dermal fibroblasts, hAECs demonstrate a decreased global DNA methylation compared to dermal fibroblasts. Likewise, quantitative gene expression analyses show that hAECs endogenously express OCT4, SOX2, KLF4, and c-MYC, all four factors used in cellular reprogramming. Thus, hAECs represent an ideal cell type for testing novel approaches for generating clinically viable iPSCs and offer significant advantages over postnatal cells that more likely may be contaminated by environmental exposures and infectious agents. PMID:22686477

  20. High individual consistency in fear of humans throughout the adult lifespan of rural and urban burrowing owls

    NASA Astrophysics Data System (ADS)

    Carrete, Martina; Tella, José L.

    2013-12-01

    Human-induced rapid environmental changes challenge individuals by creating evolutionarily novel scenarios, where species encounter novel enemies, the new species sometimes being humans themselves. However, little is known about how individuals react to human presence, specifically whether they are able to habituate to human presence, as frequently assumed, or are selected based on their fear of humans. We tested whether fear of humans (measured as flight initiation distance in a diurnal owl) is reduced through habituation to human presence (plasticity) or whether it remains unchanged throughout the individuals' life. Results show an unusually high level of individual consistency in fear of humans throughout the adult lifespan of both rural (r = 0.96) and urban (r = 0.90) birds, lending no support to habituation. Further research should assess the role of inter-individual variability in fear of humans in shaping the distribution of individuals and species in an increasingly humanized world.

  1. High individual consistency in fear of humans throughout the adult lifespan of rural and urban burrowing owls.

    PubMed

    Carrete, Martina; Tella, José L

    2013-01-01

    Human-induced rapid environmental changes challenge individuals by creating evolutionarily novel scenarios, where species encounter novel enemies, the new species sometimes being humans themselves. However, little is known about how individuals react to human presence, specifically whether they are able to habituate to human presence, as frequently assumed, or are selected based on their fear of humans. We tested whether fear of humans (measured as flight initiation distance in a diurnal owl) is reduced through habituation to human presence (plasticity) or whether it remains unchanged throughout the individuals' life. Results show an unusually high level of individual consistency in fear of humans throughout the adult lifespan of both rural (r = 0.96) and urban (r = 0.90) birds, lending no support to habituation. Further research should assess the role of inter-individual variability in fear of humans in shaping the distribution of individuals and species in an increasingly humanized world. PMID:24343659

  2. Development of the voxel computational phantoms of pediatric patients and their application to organ dose assessment

    NASA Astrophysics Data System (ADS)

    Lee, Choonik

    A series of realistic voxel computational phantoms of pediatric patients were developed and then used for the radiation risk assessment for various exposure scenarios. The high-resolution computed tomographic images of live patients were utilized for the development of the five voxel phantoms of pediatric patients, 9-month male, 4-year female, 8-year female, 11-year male, and 14-year male. The phantoms were first developed as head and torso phantoms and then extended into whole body phantoms by utilizing computed tomographic images of a healthy adult volunteer. The whole body phantom series was modified to have the same anthropometrics with the most recent reference data reported by the international commission on radiological protection. The phantoms, named as the University of Florida series B, are the first complete set of the pediatric voxel phantoms having reference organ masses and total heights. As part of the dosimetry study, the investigation on skeletal tissue dosimetry methods was performed for better understanding of the radiation dose to the active bone marrow and bone endosteum. All of the currently available methodologies were inter-compared and benchmarked with the paired-image radiation transport model. The dosimetric characteristics of the phantoms were investigated by using Monte Carlo simulation of the broad parallel beams of external phantom in anterior-posterior, posterior-anterior, left lateral, right lateral, rotational, and isotropic angles. Organ dose conversion coefficients were calculated for extensive photon energies and compared with the conventional stylized pediatric phantoms of Oak Ridge National Laboratory. The multi-slice helical computed tomography exams were simulated using Monte Carlo simulation code for various exams protocols, head, chest, abdomen, pelvis, and chest-abdomen-pelvis studies. Results have found realistic estimates of the effective doses for frequently used protocols in pediatric radiology. The results were very

  3. Sustained Engraftment of Cryopreserved Human Bone Marrow CD34(+) Cells in Young Adult NSG Mice.

    PubMed

    Wiekmeijer, Anna-Sophia; Pike-Overzet, Karin; Brugman, Martijn H; Salvatori, Daniela C F; Egeler, R Maarten; Bredius, Robbert G M; Fibbe, Willem E; Staal, Frank J T

    2014-06-01

    Hematopoietic stem cells (HSCs) are defined by their ability to repopulate the bone marrow of myeloablative conditioned and/or (lethally) irradiated recipients. To study the repopulating potential of human HSCs, murine models have been developed that rely on the use of immunodeficient mice that allow engraftment of human cells. The NSG xenograft model has emerged as the current standard for this purpose allowing for engraftment and study of human T cells. Here, we describe adaptations to the original NSG xenograft model that can be readily implemented. These adaptations encompass use of adult mice instead of newborns and a short ex vivo culture. This protocol results in robust and reproducible high levels of lympho-myeloid engraftment. Immunization of recipient mice with relevant antigen resulted in specific antibody formation, showing that both T cells and B cells were functional. In addition, bone marrow cells from primary recipients exhibited repopulating ability following transplantation into secondary recipients. Similar results were obtained with cryopreserved human bone marrow samples, thus circumventing the need for fresh cells and allowing the use of patient derived bio-bank samples. Our findings have implications for use of this model in fundamental stem cell research, immunological studies in vivo and preclinical evaluations for HSC transplantation, expansion, and genetic modification.

  4. Isolation and Characterization of Human Adult Epithelial Stem Cells from the Periodontal Ligament.

    PubMed

    Athanassiou-Papaefthymiou, M; Papagerakis, P; Papagerakis, S

    2015-11-01

    We report a novel method for the isolation of adult human epithelial stem cells (hEpiSCs) from the epithelial component of the periodontal ligament-the human epithelial cell rests of Malassez (hERM). hEpiSC-rich integrin-α6(+ve) hERM cells derived by fluorometry can be clonally expanded, can grow organoids, and express the markers of pluripotency (OCT4, NANOG, SOX2), polycomb protein RING1B, and the hEpiSC supermarker LGR5. They maintain the growth profile of their originating hERM in vitro. Subcutaneous cotransplantation with mesenchymal stem cells from the dental pulp on poly-l-lactic acid scaffolds in nude mice gave rise to perfect heterotopic ossicles in vivo with ultrastructure of dentin, enamel, cementum, and bone. These remarkable fully mineralized ossicles underscore the importance of epithelial-mesenchymal crosstalk in tissue regeneration using human progenitor stem cells, which may have already committed to lineage despite maintaining hallmarks of pluripotency. In addition, we report the clonal expansion and isolation of human LGR5(+ve) cells from the hERM in xeno-free culture conditions. The genetic profile of LGR5(+ve) cells includes both markers of pluripotency and genes important for secretory epithelial and dental epithelial cell differentiation, giving us a first insight into periodontal ligament-derived hEpiSCs. PMID:26392003

  5. In Vitro Generation of Functional Liver Organoid-Like Structures Using Adult Human Cells

    PubMed Central

    Ramachandran, Sarada Devi; Schirmer, Katharina; Münst, Bernhard; Heinz, Stefan; Ghafoory, Shahrouz; Wölfl, Stefan; Simon-Keller, Katja; Marx, Alexander; Øie, Cristina Ionica; Ebert, Matthias P.; Walles, Heike

    2015-01-01

    In this study we used differentiated adult human upcyte® cells for the in vitro generation of liver organoids. Upcyte® cells are genetically engineered cell strains derived from primary human cells by lenti-viral transduction of genes or gene combinations inducing transient proliferation capacity (upcyte® process). Proliferating upcyte® cells undergo a finite number of cell divisions, i.e., 20 to 40 population doublings, but upon withdrawal of proliferation stimulating factors, they regain most of the cell specific characteristics of primary cells. When a defined mixture of differentiated human upcyte® cells (hepatocytes, liver sinusoidal endothelial cells (LSECs) and mesenchymal stem cells (MSCs)) was cultured in vitro on a thick layer of Matrigel™, they self-organized to form liver organoid-like structures within 24 hours. When further cultured for 10 days in a bioreactor, these liver organoids show typical functional characteristics of liver parenchyma including activity of cytochromes P450, CYP3A4, CYP2B6 and CYP2C9 as well as mRNA expression of several marker genes and other enzymes. In summary, we hereby describe that 3D functional hepatic structures composed of primary human cell strains can be generated in vitro. They can be cultured for a prolonged period of time and are potentially useful ex vivo models to study liver functions. PMID:26488607

  6. Examining the relationship between childhood animal cruelty motives and recurrent adult violent crimes toward humans.

    PubMed

    Overton, Joshua C; Hensley, Christopher; Tallichet, Suzanne E

    2012-03-01

    Few researchers have studied the predictive ability of childhood animal cruelty motives as they are associated with later recurrent violence toward humans. Based on a sample of 180 inmates at one medium- and one maximum-security prison in a Southern state, the present study examines the relationship among several retrospectively identified motives (fun, out of anger, hate for the animal, and imitation) for childhood animal cruelty and the later commission of violent crimes (murder, rape, assault, and robbery) against humans. Almost two thirds of the inmates reported engaging in childhood animal cruelty for fun, whereas almost one fourth reported being motivated either out of anger or imitation. Only one fifth of the respondents reported they had committed acts of animal cruelty because they hated the animal. Regression analyses revealed that recurrent animal cruelty was the only statistically significant variable in the model. Respondents who had committed recurrent childhood animal cruelty were more likely to have had committed recurrent adult violence toward humans. None of the motives for committing childhood animal cruelty had any effect on later violence against humans.

  7. In Vitro Generation of Functional Liver Organoid-Like Structures Using Adult Human Cells.

    PubMed

    Ramachandran, Sarada Devi; Schirmer, Katharina; Münst, Bernhard; Heinz, Stefan; Ghafoory, Shahrouz; Wölfl, Stefan; Simon-Keller, Katja; Marx, Alexander; Øie, Cristina Ionica; Ebert, Matthias P; Walles, Heike; Braspenning, Joris; Breitkopf-Heinlein, Katja

    2015-01-01

    In this study we used differentiated adult human upcyte® cells for the in vitro generation of liver organoids. Upcyte® cells are genetically engineered cell strains derived from primary human cells by lenti-viral transduction of genes or gene combinations inducing transient proliferation capacity (upcyte® process). Proliferating upcyte® cells undergo a finite number of cell divisions, i.e., 20 to 40 population doublings, but upon withdrawal of proliferation stimulating factors, they regain most of the cell specific characteristics of primary cells. When a defined mixture of differentiated human upcyte® cells (hepatocytes, liver sinusoidal endothelial cells (LSECs) and mesenchymal stem cells (MSCs)) was cultured in vitro on a thick layer of Matrigel™, they self-organized to form liver organoid-like structures within 24 hours. When further cultured for 10 days in a bioreactor, these liver organoids show typical functional characteristics of liver parenchyma including activity of cytochromes P450, CYP3A4, CYP2B6 and CYP2C9 as well as mRNA expression of several marker genes and other enzymes. In summary, we hereby describe that 3D functional hepatic structures composed of primary human cell strains can be generated in vitro. They can be cultured for a prolonged period of time and are potentially useful ex vivo models to study liver functions.

  8. Non-Viral Generation of Neural Precursor-like Cells from Adult Human Fibroblasts

    PubMed Central

    Maucksch, C; Firmin, E; Butler-Munro, C; Montgomery, JM; Dottori, M; Connor, B

    2012-01-01

    Recent studies have reported direct reprogramming of human fibroblasts to mature neurons by the introduction of defined neural genes. This technology has potential use in the areas of neurological disease modeling and drug development. However, use of induced neurons for large-scale drug screening and cell-based replacement strategies is limited due to their inability to expand once reprogrammed. We propose it would be more desirable to induce expandable neural precursor cells directly from human fibroblasts. To date several pluripotent and neural transcription factors have been shown to be capable of converting mouse fibroblasts to neural stem/precursor-like cells when delivered by viral vectors. Here we extend these findings and demonstrate that transient ectopic insertion of the transcription factors SOX2 and PAX6 to adult human fibroblasts through use of non-viral plasmid transfection or protein transduction allows the generation of induced neural precursor (iNP) colonies expressing a range of neural stem and pro-neural genes. Upon differentiation, iNP cells give rise to neurons exhibiting typical neuronal morphologies and expressing multiple neuronal markers including tyrosine hydroxylase and GAD65/67. Importantly, iNP-derived neurons demonstrate electrophysiological properties of functionally mature neurons with the capacity to generate action potentials. In addition, iNP cells are capable of differentiating into glial fibrillary acidic protein (GFAP)-expressing astrocytes. This study represents a novel virusfree approach for direct reprogramming of human fibroblasts to a neural precursor fate. PMID:24693194

  9. Dynamic eye phantom for retinal oximetry measurements

    PubMed Central

    Lemaillet, Paul; Ramella-Roman, Jessica C.

    2009-01-01

    Measurements of oxygen saturation and flow in the retina can yield information about eye health and the onset of eye pathologies such as diabetic retinopathy. Recently, we developed a multiaperture camera that uses the division of the retinal image into several wavelength-sensitive subimages to compute retinal oxygen saturation. The calibration of such instruments is particularly difficult due to the layered structure of the eye and the lack of alternative measurement techniques. For this purpose, we realize an in vitro model of the human eye composed of a lens, the retina vessel, and three layers: the choroid, the retinal pigmented epithelium, and the sclera. The retinal vessel is modeled with a microtube connected to a micropump and a hemoglobin reservoir in a closed circulatory system. Hemoglobin oxygenation in the vessel could be altered using a reversible fuel cell. The sclera is represented by a Spectralon slab. The optical properties of the other layers are mimicked using titanium dioxide as a scatterer, ink as an absorber, and epoxy as a supporting structure. The optical thickness of each layer of the eye phantom is matched to each respective eye layer. PMID:20059246

  10. Dynamic eye phantom for retinal oximetry measurements

    NASA Astrophysics Data System (ADS)

    Lemaillet, Paul; Ramella-Roman, Jessica C.

    2009-11-01

    Measurements of oxygen saturation and flow in the retina can yield information about eye health and the onset of eye pathologies such as diabetic retinopathy. Recently, we developed a multiaperture camera that uses the division of the retinal image into several wavelength-sensitive subimages to compute retinal oxygen saturation. The calibration of such instruments is particularly difficult due to the layered structure of the eye and the lack of alternative measurement techniques. For this purpose, we realize an in vitro model of the human eye composed of a lens, the retina vessel, and three layers: the choroid, the retinal pigmented epithelium, and the sclera. The retinal vessel is modeled with a microtube connected to a micropump and a hemoglobin reservoir in a closed circulatory system. Hemoglobin oxygenation in the vessel could be altered using a reversible fuel cell. The sclera is represented by a Spectralon slab. The optical properties of the other layers are mimicked using titanium dioxide as a scatterer, ink as an absorber, and epoxy as a supporting structure. The optical thickness of each layer of the eye phantom is matched to each respective eye layer.

  11. Phantom Tactile Sensations Modulated by Body Position

    PubMed Central

    Medina, Jared; Rapp, Brenda

    2009-01-01

    Summary Various lines of evidence reveal bilateral activation of somatosensory areas after unilateral stimulation [1-6] assumed to be mediated by cross-hemispheric connections [7-11]. Despite evidence of bilateral activity in response to unilateral stimulation, neurologically intact humans do not experience bilateral percepts when stimulated on one side of the body. This may be due to active suppression of ipsilateral neural activity [12, 13] by inhibitory mechanisms whose functioning is poorly understood. We describe an individual with left fronto-parietal damage who experiences bilateral sensations in response to unilateral tactile stimulation—a rarely reported condition known as synchiria (previously described in visual [14], auditory [15] and somatosensory modalities [16-19]). Presumably the phantom sensations result from normal bilateral cross-hemispheric activation, combined with a failure of inhibitory mechanisms to prevent bilateral perceptual experiences. The disruption of these mechanisms provides a valuable opportunity to examine their internal functioning. We find that the synchiria rate is affected by hand position relative to multiple reference frames. Specifically, synchiria decreases as the hands move from right (contralesional) to left (ipsilesional) space in trunk- and head-centered reference frames and disappears when the hands are crossed. These findings provide, for the first time, evidence that the mechanisms that inhibit bilateral percepts operate in multiple reference frames [20-27]. PMID:19062276

  12. An MR-compatible phantom for evaluating the propagation of high intensity focused ultrasound through the skull

    NASA Astrophysics Data System (ADS)

    Hadjisavvas, V.; Mylonas, N.; Ioannides, K.; Damianou, C.

    2012-10-01

    BACKGROUND: In this paper an MR-compatible phantom for evaluating the propagation of high intensity focused ultrasound through the skull is presented. METHODS: The phantom was constructed using the thermoplastic material of ABS. The attenuation of ABS was measured using the transmission-reception method. Knowing the attenuation of human skull, the thickness of the phantom was chosen appropriately so as to achieve the same attenuation effect as in the case of human skull. The phantom was designed using CAD software and then manufactured in a rapid prototyping machine. In order to test the phantom a single element spherically focused transducer of 5 cm diameter, focusing at 10 cm and operating at either 0.5 MHz or 1 MHz was used. Brain tissue was mimicked either using gel phantoms or freshly excised tissue. RESULTS: The measured temperature due to an ultrasonic exposure with the presence of skull and without the skull was measured. It was found that the propagation of ultrasound through the skull was much better with the 0.5 MHz transducer. The skull phantom was tested also inside an MRI scanner, and we were able to detect temperature using the MRI technique of FSPGR indicating that with low frequency ultrasound propagation through the skull is possible. CONCLUSIONS: The skull phantom is a very successful tool for evaluating the propagation of ultrasound during the presence of skull.

  13. Occurrence of phantom genitalia after gender reassignment surgery.

    PubMed

    Ramachandran, V S; McGeoch, Paul D

    2007-01-01

    Transsexuals are individuals who identify as a member of the gender opposite to that which they are born. Many transsexuals report that they have always had a feeling of a mismatch between their inner gender-based "body image" and that of their body's actual physical form. Often transsexuals undergo gender reassignment surgery to convert their bodies to the sex they feel they should have been born. The vivid sensation of still having a limb although it has been amputated, a phantom limb, was first described by Weir Mitchell over a century ago. The same phenomenon is also occurs after amputation of the penis or a breast. Around 60% of men who have had to have their penis amputated for cancer will experience a phantom penis. It has recently been shown that a significant factor in these phantom sensations is "cross-activation" between the de-afferented cortex and surrounding areas. Despite this it also known that much of our body image is innately "hard-wired" into our brains; congenitally limbless patients can still experience phantom sensations. We hypothesise that, perhaps due to a dissociation during embryological development, the brains of transsexuals are "hard-wired" in manner, which is opposite to that of their biological sex. We go on to predict that male-to-female transsexuals will be much less likely to experience a phantom penis than a "normal" man who has had his penis amputated for another reason. The same will be true of female-to-male transsexuals who have had breast removal surgery. We also predict that some female-to-male transsexuals will have a phantom penis even although there is not one physically there. We believe that this is an easily testable hypothesis, which, if correct, would offer insights into both the basis of transsexuality and provide farther evidence that we have a gender specific body image, with a strong innate component that is "hard-wired" into our brains. This would furnish us with a better understanding the mechanism by which

  14. The Model Human Processor and the older adult: parameter estimation and validation within a mobile phone task.

    PubMed

    Jastrzembski, Tiffany S; Charness, Neil

    2007-12-01

    The authors estimate weighted mean values for nine information processing parameters for older adults using the Card, Moran, and Newell (1983) Model Human Processor model. The authors validate a subset of these parameters by modeling two mobile phone tasks using two different phones and comparing model predictions to a sample of younger (N = 20; M-sub(age) = 20) and older (N = 20; M-sub(age) = 69) adults. Older adult models fit keystroke-level performance at the aggregate grain of analysis extremely well (R = 0.99) and produced equivalent fits to previously validated younger adult models. Critical path analyses highlighted points of poor design as a function of cognitive workload, hardware/software design, and user characteristics. The findings demonstrate that estimated older adult information processing parameters are valid for modeling purposes, can help designers understand age-related performance using existing interfaces, and may support the development of age-sensitive technologies.

  15. Custom molded thermal MRg-FUS phantom

    NASA Astrophysics Data System (ADS)

    Eames, Matthew D. C.; Snell, John W.; Hananel, Arik; Kassell, Neal F.

    2012-11-01

    This article describes a method for creating custom-molded thermal phantoms for use with MR-guided focused ultrasound systems. The method is defined here for intracranial applications, though it may be modified for other anatomical targets.

  16. Activity, inhibition, and induction of cytochrome P450 2J2 in adult human primary cardiomyocytes.

    PubMed

    Evangelista, Eric A; Kaspera, Rüdiger; Mokadam, Nahush A; Jones, J P; Totah, Rheem A

    2013-12-01

    Cytochrome P450 2J2 plays a significant role in the epoxidation of arachidonic acid to signaling molecules important in cardiovascular events. CYP2J2 also contributes to drug metabolism and is responsible for the intestinal clearance of ebastine. However, the interaction between arachidonic acid metabolism and drug metabolism in cardiac tissue, the main expression site of CYP2J2, has not been examined. Here we investigate an adult-derived human primary cardiac cell line as a suitable model to study metabolic drug interactions (inhibition and induction) of CYP2J2 in cardiac tissue. The primary human cardiomyocyte cell line demonstrated similar mRNA-expression profiles of P450 enzymes to adult human ventricular tissue. CYP2J2 was the dominant isozyme with minor contributions from CYP2D6 and CYP2E1. Both terfenadine and astemizole oxidation were observed in this cell line, whereas midazolam was not metabolized suggesting lack of CYP3A activity. Compared with recombinant CYP2J2, terfenadine was hydroxylated in cardiomyocytes at a similar K(m) value of 1.5 μM. The V(max) of terfenadine hydroxylation in recombinant enzyme was found to be 29.4 pmol/pmol P450 per minute and in the cells 6.0 pmol/pmol P450 per minute. CYP2J2 activity in the cell line was inhibited by danazol, astemizole, and ketoconazole in submicromolar range, but also by xenobiotics known to cause cardiac adverse effects. Of the 14 compounds tested for CYP2J2 induction, only rosiglitazone increased mRNA expression, by 1.8-fold. This cell model can be a useful in vitro model to investigate the role of CYP2J2-mediated drug metabolism, arachidonic acid metabolism, and their association to drug induced cardiotoxicity. PMID:24021950

  17. Adult, embryonic and fetal hemoglobin are expressed in human glioblastoma cells.

    PubMed

    Emara, Marwan; Turner, A Robert; Allalunis-Turner, Joan

    2014-02-01

    Hemoglobin is a hemoprotein, produced mainly in erythrocytes circulating in the blood. However, non-erythroid hemoglobins have been previously reported in other cell types including human and rodent neurons of embryonic and adult brain, but not astrocytes and oligodendrocytes. Human glioblastoma multiforme (GBM) is the most aggressive tumor among gliomas. However, despite extensive basic and clinical research studies on GBM cells, little is known about glial defence mechanisms that allow these cells to survive and resist various types of treatment. We have shown previously that the newest members of vertebrate globin family, neuroglobin (Ngb) and cytoglobin (Cygb), are expressed in human GBM cells. In this study, we sought to determine whether hemoglobin is also expressed in GBM cells. Conventional RT-PCR, DNA sequencing, western blot analysis, mass spectrometry and fluorescence microscopy were used to investigate globin expression in GBM cell lines (M006x, M059J, M059K, M010b, U87R and U87T) that have unique characteristics in terms of tumor invasion and response to radiotherapy and hypoxia. The data showed that α, β, γ, δ, ζ and ε globins are expressed in all tested GBM cell lines. To our knowledge, we are the first to report expression of fetal, embryonic and adult hemoglobin in GBM cells under normal physiological conditions that may suggest an undefined function of those expressed hemoglobins. Together with our previous reports on globins (Ngb and Cygb) expression in GBM cells, the expression of different hemoglobins may constitute a part of series of active defence mechanisms supporting these cells to resist various types of treatments including chemotherapy and radiotherapy.

  18. Tissue Equivalent Phantom Design for Characterization of a Coherent Scatter X-ray Imaging System

    NASA Astrophysics Data System (ADS)

    Albanese, Kathryn Elizabeth

    Scatter in medical imaging is typically cast off as image-related noise that detracts from meaningful diagnosis. It is therefore typically rejected or removed from medical images. However, it has been found that every material, including cancerous tissue, has a unique X-ray coherent scatter signature that can be used to identify the material or tissue. Such scatter-based tissue-identification provides the advantage of locating and identifying particular materials over conventional anatomical imaging through X-ray radiography. A coded aperture X-ray coherent scatter spectral imaging system has been developed in our group to classify different tissue types based on their unique scatter signatures. Previous experiments using our prototype have demonstrated that the depth-resolved coherent scatter spectral imaging system (CACSSI) can discriminate healthy and cancerous tissue present in the path of a non-destructive x-ray beam. A key to the successful optimization of CACSSI as a clinical imaging method is to obtain anatomically accurate phantoms of the human body. This thesis describes the development and fabrication of 3D printed anatomical scatter phantoms of the breast and lung. The purpose of this work is to accurately model different breast geometries using a tissue equivalent phantom, and to classify these tissues in a coherent x-ray scatter imaging system. Tissue-equivalent anatomical phantoms were designed to assess the capability of the CACSSI system to classify different types of breast tissue (adipose, fibroglandular, malignant). These phantoms were 3D printed based on DICOM data obtained from CT scans of prone breasts. The phantoms were tested through comparison of measured scatter signatures with those of adipose and fibroglandular tissue from literature. Tumors in the phantom were modeled using a variety of biological tissue including actual surgically excised benign and malignant tissue specimens. Lung based phantoms have also been printed for future

  19. Health Human Capital in Sub-Saharan Africa: Conflicting Evidence from Infant Mortality Rates and Adult Heights

    PubMed Central

    Akachi, Yoko; Canning, David

    2011-01-01

    We investigate trends in cohort infant mortality rates and adult heights in 39 developing countries since 1960. In most regions of the world improved nutrition, and reduced childhood exposure to disease, have lead to improvements in both infant mortality and adult stature. In Sub-Saharan Africa, however, despite declining infant mortality rates, adult heights have not increased. We argue that in Sub-Saharan Africa the decline in infant mortality may have been due to interventions that prevent infant deaths rather than improved nutrition and childhood morbidity. Despite declining infant mortality, Sub-Saharan Africa may not be experiencing increases in health human capital. PMID:20634153

  20. A dosimetry intercomparison phantom for intraoperative radiotherapy.

    PubMed

    Armoogum, Kris; Watson, Colin

    2008-01-01

    Intraoperative radiotherapy (IORT) using very low kV x-rays is a promising new treatment modality and has proven to be effective for managing breast and neurological tumours. We have treated in excess of 75 patients using four Zeiss Intrabeam x-ray sources (XRS). To date there has been no published data of any dosimetric intercomparison of this type of x-ray source used at other cancer centres worldwide. This paper describes the design of a simple dosimetry intercomparison phantom for use with these very low kV x-ray sources. A prototype polymethyl methacrylate (PMMA) phantom has been manufactured, the dimensions of which were determined by the dimensions of the XRS, the beam energy and the attenuating properties of PMMA. The phantom is used in conjunction with Gafchromic XR Type-R film (GC-XRR) and its purpose is to measure the absorbed dose at a fixed distance from the effective point source at the tip of the XRS. The utility of this phantom is further enhanced through the use of an interlock, which eliminates the need to use the mobile gantry. We have used this phantom to conduct a qualitative dosimetric intercomparison of four Zeiss Intrabeam x-ray sources with positive results. This phantom is low cost, easy to manufacture, simple to use and could be adopted as a standard method of dosimetric intercomparison for Intrabeam x-ray sources as this mode of IORT becomes more widespread. PMID:18705612

  1. A nonlinear elasticity phantom containing spherical inclusions

    PubMed Central

    Pavan, Theo Z.; Madsen, Ernest L.; Frank, Gary R.; Jiang, Jingfeng; Carneiro, Antonio Adilton O.; Hall, Timothy J.

    2012-01-01

    The strain image contrast of some in vivo breast lesions changes with increasing applied load. This change is attributed to differences in the nonlinear elastic properties of the constituent tissues suggesting some potential to help classify breast diseases by their nonlinear elastic properties. A phantom with inclusions and long-term stability is desired to serve as a test bed for nonlinear elasticity imaging method development, testing, etc. This study reports a phantom designed to investigate nonlinear elastic properties with ultrasound elastographic techniques. The phantom contains four spherical inclusions and was manufactured from a mixture of gelatin, agar and oil. The phantom background and each of the inclusions has distinct Young’s modulus and nonlinear mechanical behavior. This phantom was subjected to large deformations (up to 20%) while scanning with ultrasound, and changes in strain image contrast and contrast-to-noise ratio (CNR) between inclusion and background, as a function of applied deformation, were investigated. The changes in contrast over a large deformation range predicted by the finite element analysis (FEA) were consistent with those experimentally observed. Therefore, the paper reports a procedure for making phantoms with predictable nonlinear behavior, based on independent measurements of the constituent materials, and shows that the resulting strain images (e.g., strain contrast) agrees with that predicted with nonlinear FEA. PMID:22772074

  2. The phantom robot - Predictive displays for teleoperation with time delay

    NASA Technical Reports Server (NTRS)

    Bejczy, Antal K.; Kim, Won S.; Venema, Steven C.

    1990-01-01

    An enhanced teleoperation technique for time-delayed bilateral teleoperator control is discussed. The control technique selected for time delay is based on the use of a high-fidelity graphics phantom robot that is being controlled in real time (without time delay) against the static task image. Thus, the motion of the phantom robot image on the monitor predicts the motion of the real robot. The real robot's motion will follow the phantom robot's motion on the monitor with the communication time delay implied in the task. Real-time high-fidelity graphics simulation of a PUMA arm is generated and overlaid on the actual camera view of the arm. A simple camera calibration technique is used for calibrated graphics overlay. A preliminary experiment is performed with the predictive display by using a very simple tapping task. The results with this simple task indicate that predictive display enhances the human operator's telemanipulation task performance significantly during free motion when there is a long time delay. It appears, however, that either two-view or stereoscopic predictive displays are necessary for general three-dimensional tasks.

  3. Depolarization of light by rough surface of scattering phantoms

    NASA Astrophysics Data System (ADS)

    Tchvialeva, Lioudmila; Markhvida, Igor; Lee, Tim K.; Doronin, Alexander; Meglinski, Igor

    2013-02-01

    The growing interest in biomedical optics to the polarimetric methods push researchers to better understand of light depolarization during scattering in and on the surface of biological tissues. Here we study the depolarization of light propagated in silicone phantoms. The phantoms with variety of surface roughness and bulk optical properties are designed to imitate human skin. Free-space speckle patterns in parallel (III) and perpendicular (I⊥) direction in respect to incident polarization are used to get the depolarization ratio of backscattered light DR = (III - I⊥)/( III + I⊥). The Monte Carlo model developed in house is also applied to compare simulated DR with experimentally measured. DR dependence on roughness, concentration and size of scattering particles is analysed. A weak depolarization and negligible response to scattering of the medium are observed for phantoms with smooth surfaces, whereas for the surface roughness in order to the mean free path the depolarization ratio decreases and reveals dependence on the bulk scattering coefficient. In is shown that the surface roughness could be a key factor triggering the ability of tissues' characterization by depolarization ratio.

  4. From the Cover: Cell-replacement therapy for diabetes: Generating functional insulin-producing tissue from adult human liver cells

    NASA Astrophysics Data System (ADS)

    Sapir, Tamar; Shternhall, Keren; Meivar-Levy, Irit; Blumenfeld, Tamar; Cohen, Hamutal; Skutelsky, Ehud; Eventov-Friedman, Smadar; Barshack, Iris; Goldberg, Iris; Pri-Chen, Sarah; Ben-Dor, Lya; Polak-Charcon, Sylvie; Karasik, Avraham; Shimon, Ilan; Mor, Eytan; Ferber, Sarah

    2005-05-01

    Shortage in tissue availability from cadaver donors and the need for life-long immunosuppression severely restrict the large-scale application of cell-replacement therapy for diabetic patients. This study suggests the potential use of adult human liver as alternate tissue for autologous beta-cell-replacement therapy. By using pancreatic and duodenal homeobox gene 1 (PDX-1) and soluble factors, we induced a comprehensive developmental shift of adult human liver cells into functional insulin-producing cells. PDX-1-treated human liver cells express insulin, store it in defined granules, and secrete the hormone in a glucose-regulated manner. When transplanted under the renal capsule of diabetic, immunodeficient mice, the cells ameliorated hyperglycemia for prolonged periods of time. Inducing developmental redirection of adult liver offers the potential of a cell-replacement therapy for diabetics by allowing the patient to be the donor of his own insulin-producing tissue. pancreas | transdifferentiation

  5. Reproducibility of dual-photon absorptiometry using a clinical phantom

    SciTech Connect

    DaCosta, M.; DeLaney, M.; Goldsmith, S.J.

    1985-05-01

    The use of dual-photon absorptiometry (DPA) bone mineral density (BMD) to monitor bone for diagnosis and monitoring therapy of osteoporosis has been established. The objective of this study is to determine the reproducibility of DPA measurements. A phantom was constructed using a section of human boney pelvis and lumbo-sacral spine. Provisions were made to mimic changes in patient girth. To evaluate the DPA reproducibility within a single day, 12 consecutive studies were performed on the phantom using standard acquisition and processing procedures. The mean BMD +-1 SD in gms/cm/sup 2/ (BMD-bar)of lumbar vertebrae 2-4 was 0.771 +- 0.007 with a 0.97% coefficient of variation (1SD) (CV). This evaluation was repeated 7 times over the next 4 months with the performance of 3 to 6 studies each time, the maximum CV found was 1.93. In order to evaluate the DPA reproducibility with time, phantom studies were performed over a 7 month period which included a 153-Gd source change. The BMD-bar was 0.770 +- 0.017 with a 2.15CV. DPA reproducibility with patient girth changes was evaluated by performing the phantom studies at water depths of 12.5, 17.0 and 20.0cm. Five studies of each were performed using standard acquisition and processing procedures. The BMD-bar was 0.779 +- 0.012 with a 1.151CV. based on these results, BMD measurements by DPA are reproducible within 2%. This reliability is maintained for studies performed over extended period of time and are independent of changes in patient girth.

  6. Feasibility study of a novel intraosseous device in adult human cadavers

    PubMed Central

    Singh, Sandeep; Aggarwal, Praveen; Lodha, Rakesh; Agarwal, Ramesh; Gupta, Arun Kr.; Dhingra, Renu; Karve, Jayant Sitaram; Jaggu, Srinivas Kiran; Bhargava, Balram

    2016-01-01

    Background & objectives: Intraosseous (IO) access is an alternative to difficult intravenous (iv) access during emergency clinical situations. Existing IO solutions are expensive, require power supply and trained manpower; limiting their use in resource constrained settings. To address these limitations, a novel IO device has been developed. The objectives of this study were to evaluate functionality and safety of this device in adult human cadavers. Methods: The ability of the IO device to penetrate the proximal and/or distal tibia was evaluated in three adult cadavers. Subjective parameters of loss of resistance, stable needle hold, easy needle withdrawal and any damage to the device were evaluated during the study. The insertion time was the objective parameter measured. Four sets of radiographs per insertion confirmed the position of the needle and identified complications. Results: A single physician performed 12 IO access procedures using the same device. Penetration of proximal and/or distal tibia was achieved in all instances. It was successful in the first attempt in eight (66.7%) and during second attempt in the remaining. The mean time to insertion was 4.1 ± 3.1 sec. Appropriate insertion of needle in the intra-medullary space of bone was confirmed with radiological examination in 10 (83.3%) insertions. In two occasions after penetrating the cortical layer of bone, the device overshot the intra-medullary space, as detected by radiological examination. Device got bent during insertion in one instance. There was no evidence of needle breakage or bone fracture. The needle could be withdrawn effortlessly in all instances. Interpretation & conclusions: The novel IO device could successfully penetrate the adult cadaver bones in most cases. Further studies are needed to confirm these results on a large sample. PMID:27241639

  7. Behaviour of Solitary Adult Scandinavian Brown Bears (Ursus arctos) when Approached by Humans on Foot

    PubMed Central

    Moen, Gro Kvelprud; Støen, Ole-Gunnar; Sahlén, Veronica; Swenson, Jon E.

    2012-01-01

    Successful management has brought the Scandinavian brown bear (Ursus arctos L.) back from the brink of extinction, but as the population grows and expands the probability of bear-human encounters increases. More people express concerns about spending time in the forest, because of the possibility of encountering bears, and acceptance for the bear is decreasing. In this context, reliable information about the bear's normal behaviour during bear-human encounters is important. Here we describe the behaviour of brown bears when encountering humans on foot. During 2006–2009, we approached 30 adult (21 females, 9 males) GPS-collared bears 169 times during midday, using 1-minute positioning before, during and after the approach. Observer movements were registered with a handheld GPS. The approaches started 869±348 m from the bears, with the wind towards the bear when passing it at approximately 50 m. The bears were detected in 15% of the approaches, and none of the bears displayed any aggressive behaviour. Most bears (80%) left the initial site during the approach, going away from the observers, whereas some remained at the initial site after being approached (20%). Young bears left more often than older bears, possibly due to differences in experience, but the difference between ages decreased during the berry season compared to the pre-berry season. The flight initiation distance was longer for active bears (115±94 m) than passive bears (69±47 m), and was further affected by horizontal vegetation cover and the bear's age. Our findings show that bears try to avoid confrontations with humans on foot, and support the conclusions of earlier studies that the Scandinavian brown bear is normally not aggressive during encounters with humans. PMID:22363710

  8. Human Adult Dental Pulp Stem Cells Enhance Poststroke Functional Recovery Through Non-Neural Replacement Mechanisms

    PubMed Central

    Leong, Wai Khay; Henshall, Tanya L.; Arthur, Agnes; Kremer, Karlea L.; Lewis, Martin D.; Helps, Stephen C.; Field, John; Hamilton-Bruce, Monica A.; Warming, Scott; Manavis, Jim; Vink, Robert; Gronthos, Stan

    2012-01-01

    Human adult dental pulp stem cells (DPSCs), derived from third molar teeth, are multipotent and have the capacity to differentiate into neurons under inductive conditions both in vitro and following transplantation into the avian embryo. In this study, we demonstrate that the intracerebral transplantation of human DPSCs 24 hours following focal cerebral ischemia in a rodent model resulted in significant improvement in forelimb sensorimotor function at 4 weeks post-treatment. At this time, 2.3 ± 0.7% of engrafted cells had survived in the poststroke brain and demonstrated targeted migration toward the stroke lesion. In the peri-infarct striatum, transplanted DPSCs differentiated into astrocytes in preference to neurons. Our data suggest that the dominant mechanism of action underlying DPSC treatment that resulted in enhanced functional recovery is unlikely to be due to neural replacement. Functional improvement is more likely to be mediated through DPSC-dependent paracrine effects. This study provides preclinical evidence for the future use of human DPSCs in cell therapy to improve outcome in stroke patients. PMID:23197777

  9. Parietal Bone Thickness and Vascular Diameters in Adult Modern Humans: A Survey on Cranial Remains.

    PubMed

    Eisová, Stanislava; Rangel de Lázaro, Gizéh; Píšová, Hana; Pereira-Pedro, Sofia; Bruner, Emiliano

    2016-07-01

    Cranial bone thickness varies among modern humans, and many factors influencing this variability remain unclear. Growth hormones and physical activity are thought to influence the vault thickness. Considering that both systemic factors and energy supply influence the vascular system, and taking into account the structural and biomechanical interaction between endocranial vessels and vault bones, in this study we evaluate the correlation between vascular and bone diameters. In particular, we tested the relationship between the thickness of the parietal bone (which is characterized, in modern humans, by a complex vascular network) and the lumen size of the middle meningeal and diploic vessels, in adult modern humans. Our results show no patent correlation between the thickness of parietal bone and the size of the main vascular channels. Values and distributions of the branching patterns, as well as anatomical relationships between vessels and bones, are also described in order to provide information concerning the arrangement of the endocranial vascular morphology. This information is relevant in both evolutionary and medical contexts. Anat Rec, 299:888-896, 2016. © 2016 Wiley Periodicals, Inc. PMID:27072555

  10. Prevalence of human norovirus and Clostridium difficile coinfections in adult hospitalized patients

    PubMed Central

    Stokely, Janelle N; Niendorf, Sandra; Taube, Stefan; Hoehne, Marina; Young, Vincent B; Rogers, Mary AM; Wobus, Christiane E

    2016-01-01

    Objective Human norovirus (HuNoV) and Clostridium difficile are common causes of infectious gastroenteritis in adults in the US. However, limited information is available regarding HuNoV and C. difficile coinfections. Our study was designed to evaluate the prevalence of HuNoV and C. difficile coinfections among adult patients in a hospital setting and disease symptomatology. Study design and setting For a cross-sectional analysis, 384 fecal samples were tested for the presence of C. difficile toxins from patients (n=290), whom the provider suspected of C. difficile infections. Subsequent testing was then performed for HuNoV genogroups I and II. Multinomial logistic regression was performed to determine symptoms more frequently associated with coinfections. Results The final cohort consisted of the following outcome groups: C. difficile (n=196), C. difficile + HuNoV coinfection (n=40), HuNoV only (n=12), and neither (n=136). Coinfected patients were more likely to develop nausea, gas, and abdominal pain and were more likely to seek treatment in the winter season compared with individuals not infected or infected with either pathogen alone. Conclusion Our study revealed that patients with coinfection are more likely to experience certain gastrointestinal symptoms, in particular abdominal pain, suggesting an increased severity of disease symptomatology in coinfected patients. PMID:27418856

  11. Differential Oxidative Stress Induced by Dengue Virus in Monocytes from Human Neonates, Adult and Elderly Individuals

    PubMed Central

    Valero, Nereida; Mosquera, Jesús; Añez, Germán; Levy, Alegria; Marcucci, Rafael; de Mon, Melchor Alvarez

    2013-01-01

    Changes in immune response during lifespan of man are well known. These changes involve decreased neonatal and elderly immune response. In addition, it has been shown a relationship between immune and oxidative mechanisms, suggesting that altered immune response could be associated to altered oxidative response. Increased expression of nitric oxide (NO) has been documented in dengue and in monocyte cultures infected with different types of dengue virus. However, there is no information about the age-dependent NO oxidative response in humans infected by dengue virus. In this study, monocyte cultures from neonatal, elderly and adult individuals (n = 10 each group) were infected with different dengue virus types (DENV- 1 to 4) and oxidative/antioxidative responses and apoptosis were measured at days 1 and 3 of culture. Increased production of NO, lipid peroxidation and enzymatic and nonenzymatic anti-oxidative responses in dengue infected monocyte cultures were observed. However, neonatal and elderly monocytes had lower values of studied parameters when compared to those in adult-derived cultures. Apoptosis was present in infected monocytes with higher values at day 3 of culture. This reduced oxidant/antioxidant response of neonatal and elderly monocytes could be relevant in the pathogenesis of dengue disease. PMID:24069178

  12. Comparison of Human Neonatal and Adult Blood Leukocyte Subset Composition Phenotypes.

    PubMed

    Prabhu, Savit B; Rathore, Deepak K; Nair, Deepa; Chaudhary, Anita; Raza, Saimah; Kanodia, Parna; Sopory, Shailaja; George, Anna; Rath, Satyajit; Bal, Vineeta; Tripathi, Reva; Ramji, Siddharth; Batra, Aruna; Aggarwal, Kailash C; Chellani, Harish K; Arya, Sugandha; Agarwal, Nidhi; Mehta, Umesh; Natchu, Uma Chandra Mouli; Wadhwa, Nitya; Bhatnagar, Shinjini

    2016-01-01

    The human peripheral leukocyte subset composition depends on genotype variation and pre-natal and post-natal environmental influence diversity. We quantified this composition in adults and neonates, and compared the median values and dispersal ranges of various subsets in them. We confirmed higher frequencies of monocytes and regulatory T cells (Tregs), similar frequencies of neutrophils, and lower frequencies of CD8 T cells, NKT cells, B1 B cells and gamma-delta T cells in neonatal umbilical cord blood. Unlike previous reports, we found higher frequencies of eosinophils and B cells, higher CD4:CD8 ratios, lower frequencies of T cells and iNKT cells, and similar frequencies of CD4 T cells and NK cells in neonates. We characterized monocyte subsets and dendritic cell (DC) subsets in far greater detail than previously reported, using recently described surface markers and gating strategies and observed that neonates had lower frequencies of patrolling monocytes and lower myeloid dendritic cell (mDC):plasmacytoid DC (pDC) ratios. Our data contribute to South Asian reference values for these parameters. We found that dispersal ranges differ between different leukocyte subsets, suggesting differential determination of variation. Further, some subsets were more dispersed in adults than in neonates suggesting influences of postnatal sources of variation, while some show the opposite pattern suggesting influences of developmental process variation. Together, these data and analyses provide interesting biological possibilities for future exploration. PMID:27610624

  13. Human oocytes reprogram adult somatic nuclei of a type 1 diabetic to diploid pluripotent stem cells.

    PubMed

    Yamada, Mitsutoshi; Johannesson, Bjarki; Sagi, Ido; Burnett, Lisa Cole; Kort, Daniel H; Prosser, Robert W; Paull, Daniel; Nestor, Michael W; Freeby, Matthew; Greenberg, Ellen; Goland, Robin S; Leibel, Rudolph L; Solomon, Susan L; Benvenisty, Nissim; Sauer, Mark V; Egli, Dieter

    2014-06-26

    The transfer of somatic cell nuclei into oocytes can give rise to pluripotent stem cells that are consistently equivalent to embryonic stem cells, holding promise for autologous cell replacement therapy. Although methods to induce pluripotent stem cells from somatic cells by transcription factors are widely used in basic research, numerous differences between induced pluripotent stem cells and embryonic stem cells have been reported, potentially affecting their clinical use. Because of the therapeutic potential of diploid embryonic stem-cell lines derived from adult cells of diseased human subjects, we have systematically investigated the parameters affecting efficiency of blastocyst development and stem-cell derivation. Here we show that improvements to the oocyte activation protocol, including the use of both kinase and translation inhibitors, and cell culture in the presence of histone deacetylase inhibitors, promote development to the blastocyst stage. Developmental efficiency varied between oocyte donors, and was inversely related to the number of days of hormonal stimulation required for oocyte maturation, whereas the daily dose of gonadotropin or the total number of metaphase II oocytes retrieved did not affect developmental outcome. Because the use of concentrated Sendai virus for cell fusion induced an increase in intracellular calcium concentration, causing premature oocyte activation, we used diluted Sendai virus in calcium-free medium. Using this modified nuclear transfer protocol, we derived diploid pluripotent stem-cell lines from somatic cells of a newborn and, for the first time, an adult, a female with type 1 diabetes.

  14. Sex differences in spatial navigation and perception in human adolescents and emerging adults

    PubMed Central

    Sneider, Jennifer Tropp; Hamilton, Derek A.; Cohen-Gilbert, Julia E.; Crowley, David J.; Rosso, Isabelle M.; Silveri, Marisa M.

    2014-01-01

    Males typically outperform females on spatial tasks, beginning early in life and continuing into adulthood. This study aimed to characterize age and sex differences in human spatial ability using a virtual Water Maze Task (vWMT), which is based on the classic Morris water maze spatial navigation task used in rodents. Performance on the vWMT and on a task assessing visuospatial perception, Mental Rotations Test (MRT), was examined in 33 adolescents and 39 emerging adults. For the vWMT, significant effects of age and sex were observed for path length in the target region (narrower spatial sampling), and heading error, with emerging adults performing better than adolescents, and an overall male advantage. For the MRT, males scored higher than females, but only in emerging adulthood. Overall, sex differences in visuospatial perception (MRT) emerge differently from those observed on a classic navigation task, with age and sex-specific superior vWMT performance likely related to the use of more efficient strategies. Importantly, these results extend the developmental timeline of spatial ability characterization to include adolescent males and females performing a virtual version of the classic vWMT. PMID:25464337

  15. Collection of Clonorchis sinensis adult worms from infected humans after praziquantel treatment

    PubMed Central

    Shen, Chenghua; Kim, Jae-hwan; Lee, Jeong-Keun; Bae, Young Mee; Oh, Jin-Kyoung; Lim, Min Kyung; Shin, Hai-Rim; Hong, Sung-Tae

    2007-01-01

    A cohort was established for evaluation of cancer risk factors in Sancheong-gun, Gyeongsangnam-do, Korea. As one of the cohort studies, stools of 947 residents (403 males and 544 females, age range: 29-86 years) were screened for Clonorchis sinensis eggs using both Kato-Katz method and formalin-ether sedimentation technique. The overall egg positive rate of C. sinensis was 37.7% and individual EPG (eggs per gram of feces) counts ranged from 24 to 28,800. Eight egg positive residents voluntarily joined a process of collection of the passed worms after praziquantel treatment. A total of 158 worms were recovered from 5 of the 8 treated persons, ranged from 3 to 108 in each individual. The worms were 15-20 mm × 2-3 mm in size, and showed brown-pigmented, red, or white body colors. This is the first collection record of C. sinensis adult worms from humans through anthelmintic treatment and purgation. The adult worms of C. sinensis may be paralyzed by praziquantel and then discharged passively through bile flow in the bile duct and by peristaltic movement of the bowel. PMID:17570980

  16. Micropatterning control of tubular commitment in human adult renal stem cells.

    PubMed

    Sciancalepore, Anna G; Portone, Alberto; Moffa, Maria; Persano, Luana; De Luca, Maria; Paiano, Aurora; Sallustio, Fabio; Schena, Francesco P; Bucci, Cecilia; Pisignano, Dario

    2016-07-01

    The treatment of renal injury by autologous, patient-specific adult stem cells is still an unmet need. Unsolved issues remain the spatial integration of stem cells into damaged areas of the organ, the commitment in the required cell type and the development of improved bioengineered devices. In this respect, biomaterials and architectures have to be specialized to control stem cell differentiation. Here, we perform an extensive study on micropatterned extracellular matrix proteins, which constitute a simple and non-invasive approach to drive the differentiation of adult renal progenitor/stem cells (ARPCs) from human donors. ARPCs are interfaced with fibronectin (FN) micropatterns, in the absence of exogenous chemicals or cellular reprogramming. We obtain the differentiation towards tubular cells of ARPCs cultured in basal medium conditions, the tubular commitment thus being specifically induced by micropatterned substrates. We characterize the stability of the tubular differentiation as well as the induction of a polarized phenotype in micropatterned ARPCs. Thus, the developed cues, driving the functional commitment of ARPCs, offer a route to recreate the microenvironment of the stem cell niche in vitro, that may serve, in perspective, for the development of ARPC-based bioengineered devices. PMID:27105437

  17. Schistosoma mansoni Sambon, 1907: morphometric differences between adult worms from sympatric rodent and human isolates.

    PubMed

    Neves, R H; Pereira, M J; de Oliveira, R M; Gomes, D C; Machado-Silva, J R

    1998-01-01

    A computer software for image analysis (IMAGE PRO PLUS, MEDIA CYBERNETICS) was utilized in male and females adult worms, aiming the morphological characterization of Schistosoma mansoni samples isolated from a slyvatic rodent, Nectomys squamipes, and humans in Sumidouro, Rio de Janeiro, Brazil and recovered from Mus musculus C3H/He. The following characters for males's testicular lobes were analyzed: number, area, density, larger and smaller diameter, longer and shorter axis and perimeter and extension; for females: area, longer and shorter axis, larger and smaller diameter and perimeter of the eggs and spine; oral and ventral suckers area and distance between them in both sex were determined. By the analysis of variance (one way ANOVA) significant differences (p < 0.05) were observed in all studied characters, except for the density of testicular lobes. Significant differences (p < 0.05) were detected for all characters in the female worms. Data ratify that sympatric isolates present phenotypic differences and the adult female characters are useful for the proper identification of S. mansoni isolates.

  18. Comparison of Human Neonatal and Adult Blood Leukocyte Subset Composition Phenotypes

    PubMed Central

    Rathore, Deepak K.; Nair, Deepa; Chaudhary, Anita; Raza, Saimah; Kanodia, Parna; Sopory, Shailaja; George, Anna; Rath, Satyajit; Bal, Vineeta; Tripathi, Reva; Ramji, Siddharth; Batra, Aruna; Aggarwal, Kailash C.; Chellani, Harish K.; Arya, Sugandha; Agarwal, Nidhi; Mehta, Umesh; Natchu, Uma Chandra Mouli; Wadhwa, Nitya; Bhatnagar, Shinjini

    2016-01-01

    The human peripheral leukocyte subset composition depends on genotype variation and pre-natal and post-natal environmental influence diversity. We quantified this composition in adults and neonates, and compared the median values and dispersal ranges of various subsets in them. We confirmed higher frequencies of monocytes and regulatory T cells (Tregs), similar frequencies of neutrophils, and lower frequencies of CD8 T cells, NKT cells, B1 B cells and gamma-delta T cells in neonatal umbilical cord blood. Unlike previous reports, we found higher frequencies of eosinophils and B cells, higher CD4:CD8 ratios, lower frequencies of T cells and iNKT cells, and similar frequencies of CD4 T cells and NK cells in neonates. We characterized monocyte subsets and dendritic cell (DC) subsets in far greater detail than previously reported, using recently described surface markers and gating strategies and observed that neonates had lower frequencies of patrolling monocytes and lower myeloid dendritic cell (mDC):plasmacytoid DC (pDC) ratios. Our data contribute to South Asian reference values for these parameters. We found that dispersal ranges differ between different leukocyte subsets, suggesting differential determination of variation. Further, some subsets were more dispersed in adults than in neonates suggesting influences of postnatal sources of variation, while some show the opposite pattern suggesting influences of developmental process variation. Together, these data and analyses provide interesting biological possibilities for future exploration. PMID:27610624

  19. Sex differences in spatial navigation and perception in human adolescents and emerging adults.

    PubMed

    Sneider, Jennifer T; Hamilton, Derek A; Cohen-Gilbert, Julia E; Crowley, David J; Rosso, Isabelle M; Silveri, Marisa M

    2015-02-01

    Males typically outperform females on spatial tasks, beginning early in life and continuing into adulthood. This study aimed to characterize age and sex differences in human spatial ability using a virtual Water Maze Task (vWMT), which is based on the classic Morris water maze spatial navigation task used in rodents. Performance on the vWMT and on a task assessing visuospatial perception, Mental Rotations Test (MRT), was examined in 33 adolescents and 39 emerging adults. For the vWMT, significant effects of age and sex were observed for path length in the target region (narrower spatial sampling), and heading error, with emerging adults performing better than adolescents, and an overall male advantage. For the MRT, males scored higher than females, but only in emerging adulthood. Overall, sex differences in visuospatial perception (MRT) emerge differently from those observed on a classic navigation task, with age and sex-specific superior vWMT performance likely related to the use of more efficient strategies. Importantly, these results extend the developmental timeline of spatial ability characterization to include adolescent males and females performing a virtual version of the classic vWMT. PMID:25464337