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Sample records for asian phantom results

  1. Initial quality performance results using a phantom to simulate chest computed radiography.

    Science.gov (United States)

    Muhogora, Wilbroad; Padovani, Renato; Msaki, Peter

    2011-01-01

    The aim of this study was to develop a homemade phantom for quantitative quality control in chest computed radiography (CR). The phantom was constructed from copper, aluminium, and polymenthylmethacrylate (PMMA) plates as well as Styrofoam materials. Depending on combinations, the literature suggests that these materials can simulate the attenuation and scattering characteristics of lung, heart, and mediastinum. The lung, heart, and mediastinum regions were simulated by 10 mm x 10 mm x 0.5 mm, 10 mm x 10 mm x 0.5 mm and 10 mm x 10 mm x 1 mm copper plates, respectively. A test object of 100 mm x 100 mm and 0.2 mm thick copper was positioned to each region for CNR measurements. The phantom was exposed to x-rays generated by different tube potentials that covered settings in clinical use: 110-120 kVp (HVL=4.26-4.66 mm Al) at a source image distance (SID) of 180 cm. An approach similar to the recommended method in digital mammography was applied to determine the CNR values of phantom images produced by a Kodak CR 850A system with post-processing turned off. Subjective contrast-detail studies were also carried out by using images of Leeds TOR CDR test object acquired under similar exposure conditions as during CNR measurements. For clinical kVp conditions relevant to chest radiography, the CNR was highest over 90-100 kVp range. The CNR data correlated with the results of contrast detail observations. The values of clinical tube potentials at which CNR is the highest are regarded to be optimal kVp settings. The simplicity in phantom construction can offer easy implementation of related quality control program.

  2. Initial quality performance results using a phantom to simulate chest computed radiography

    Directory of Open Access Journals (Sweden)

    Muhogora Wilbroad

    2011-01-01

    Full Text Available The aim of this study was to develop a homemade phantom for quantitative quality control in chest computed radiography (CR. The phantom was constructed from copper, aluminium, and polymenthylmethacrylate (PMMA plates as well as Styrofoam materials. Depending on combinations, the literature suggests that these materials can simulate the attenuation and scattering characteristics of lung, heart, and mediastinum. The lung, heart, and mediastinum regions were simulated by 10 mm x 10 mm x 0.5 mm, 10 mm x 10 mm x 0.5 mm and 10 mm x 10 mm x 1 mm copper plates, respectively. A test object of 100 mm x 100 mm and 0.2 mm thick copper was positioned to each region for CNR measurements. The phantom was exposed to x-rays generated by different tube potentials that covered settings in clinical use: 110-120 kVp (HVL=4.26-4.66 mm Al at a source image distance (SID of 180 cm. An approach similar to the recommended method in digital mammography was applied to determine the CNR values of phantom images produced by a Kodak CR 850A system with post-processing turned off. Subjective contrast-detail studies were also carried out by using images of Leeds TOR CDR test object acquired under similar exposure conditions as during CNR measurements. For clinical kVp conditions relevant to chest radiography, the CNR was highest over 90-100 kVp range. The CNR data correlated with the results of contrast detail observations. The values of clinical tube potentials at which CNR is the highest are regarded to be optimal kVp settings. The simplicity in phantom construction can offer easy implementation of related quality control program.

  3. Contrast-enhanced digital mammography (CEDM): phantom experiment and first clinical results

    Science.gov (United States)

    Marx, Christiane; Facius, Mirijam; Muller, Serge L.; Benali, Karim; Malich, Ansgar; Kaiser, Werner

    2002-05-01

    The introduction of the Full Field Digital Mammography (FFDM) opens the way to a large range of future advanced applications. Among them, Contrast Enhanced Digital Mammography (CEDM) could be a fast and less expensive alternative to Magnetic Resonance Imaging (MRI) for breast lesion characterization. In this work, we have investigated, first on phantom then on patients, the capability of a modified FFDM system to show the contrast enhancement of lesions after intra-venous injection of iodine. The uptake has been estimated from the difference between pre- and post-contrast images. Phantom results showed that 1) detectability thresholds of the contrast media were compatible with clinical conditions; 2) breast radiological thickness has a low impact on uptake detectability; 3) spatial and temporal analysis showed delayed margin contrast uptake of the simulated lesion and slow increase of contrast in the background. Preliminary results on patients have confirmed the phantom results and have shown a contrast uptake in all malignant lesions despite the observed patient motion artifacts, and some moderate signal variability. This study demonstrated the feasibility of the Contrast Enhanced Digital Mammography technique. Further investigations and clinical validations will have to be completed before it can be widely used in a daily routine practice.

  4. Phantom thermodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Diaz, Pedro F. [Colina de los Chopos, Centro de Fisica ' Miguel A. Catalan' , Instituto de Matematicas y Fisica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 121, 28006 Madrid (Spain)]. E-mail: p.gonzalezdiaz@imaff.cfmac.csic.es; Sigueenza, Carmen L. [Colina de los Chopos, Centro de Fisica ' Miguel A. Catalan' , Instituto de Matematicas y Fisica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 121, 28006 Madrid (Spain)

    2004-10-04

    This paper deals with the thermodynamic properties of a phantom field in a flat Friedmann-Robertson-Walker universe. General expressions for the temperature and entropy of a general dark-energy field with equation of state p={omega}{rho} are derived from which we have deduced that, whereas the temperature of a cosmic phantom fluid ({omega}-1) is definite negative, its entropy is always positive. We interpret that result in terms of the intrinsic quantum nature of the phantom field and apply it to (i) attain a consistent explanation for some recent results concerning the evolution of black holes which,induced by accreting phantom energy, gradually loss their mass to finally vanish exactly at the big rip, and (ii) introduce the concept of cosmological information and its relation with life and the anthropic principle. Some quantum statistical-thermodynamic properties of the quantum field are also considered that include a generalized Wien law and the prediction of some novel phenomena such as the stimulated absorption of phantom energy and the anti-laser effect.

  5. Initial quality performance results using a phantom to simulate chest computed radiography

    OpenAIRE

    Muhogora Wilbroad; Padovani Renato; Msaki Peter

    2011-01-01

    The aim of this study was to develop a homemade phantom for quantitative quality control in chest computed radiography (CR). The phantom was constructed from copper, aluminium, and polymenthylmethacrylate (PMMA) plates as well as Styrofoam materials. Depending on combinations, the literature suggests that these materials can simulate the attenuation and scattering characteristics of lung, heart, and mediastinum. The lung, heart, and mediastinum regions were simulated by 10 mm x 10 mm x 0.5 mm...

  6. Mammographic compression in Asian women

    Science.gov (United States)

    Lau, Susie; Abdul Aziz, Yang Faridah; Ng, Kwan Hoong

    2017-01-01

    Objectives To investigate: (1) the variability of mammographic compression parameters amongst Asian women; and (2) the effects of reducing compression force on image quality and mean glandular dose (MGD) in Asian women based on phantom study. Methods We retrospectively collected 15818 raw digital mammograms from 3772 Asian women aged 35–80 years who underwent screening or diagnostic mammography between Jan 2012 and Dec 2014 at our center. The mammograms were processed using a volumetric breast density (VBD) measurement software (Volpara) to assess compression force, compression pressure, compressed breast thickness (CBT), breast volume, VBD and MGD against breast contact area. The effects of reducing compression force on image quality and MGD were also evaluated based on measurement obtained from 105 Asian women, as well as using the RMI156 Mammographic Accreditation Phantom and polymethyl methacrylate (PMMA) slabs. Results Compression force, compression pressure, CBT, breast volume, VBD and MGD correlated significantly with breast contact area (pimage quality (p>0.05). Conclusions Force-standardized protocol led to widely variable compression parameters in Asian women. Based on phantom study, it is feasible to reduce compression force up to 32.5% with minimal effects on image quality and MGD. PMID:28419125

  7. The impact of audio-visual biofeedback on 4D PET images: results of a phantom study.

    Science.gov (United States)

    Yang, Jaewon; Yamamoto, Tokihiro; Cho, Byungchul; Seo, Youngho; Keall, Paul J

    2012-02-01

    Irregular breathing causes motion blurring artifacts in 4D PET images. Audiovisual (AV) biofeedback has been demonstrated to improve breathing regularity. To investigate the hypothesis that, compared with free breathing, motion blurring artifacts are reduced with AV biofeedback, the authors performed the first experimental phantom-based quantification of the impact of AV biofeedback on 4D PET image quality. The authors acquired 4D PET dynamic phantom images with AV biofeedback and free breathing by moving a phantom programmed with AV biofeedback trained and free breathing respiratory traces of ten healthy subjects. The authors also acquired stationary phantom images for reference. The phantom was cylindrical with six hollow sphere targets (10, 13, 17, 22, 28, and 37 mm in diameter). The authors quantified motion blurring using the target diameter, Dice coefficient and recovery coefficient (RC) metrics to estimate the effect of motion. The average increase in target diameter for AV biofeedback was 0.6±1.6mm (4.7±13%), which was significantly (pimpact of target sizes was more dominant than that of motion. In addition, the authors observed large variations in the results with respect to target sizes, subject traces and respiratory bins due to partial volume effects and respiratory motion irregularity. The results indicate that AV biofeedback can significantly reduce motion blurring artifacts and may facilitate improved identification and localization of lung tumors in 4D PET images. The results justify proceeding with clinical studies to quantify the impact of AV biofeedback on 4D PET image quality and tumor detectability.

  8. Sociodemographic Correlates of Dietary Practices among Asian-Americans: Results from the California Health Interview Survey.

    Science.gov (United States)

    Sarwar, Evangel; Arias, Devin; Becerra, Benjamin J; Becerra, Monideepa Bhattacharya

    2015-12-01

    Studies show that Asian-American subgroups do not always meet dietary recommendations and are at high risk of cardiovascular diseases. The purpose of our research is to illustrate the various sociodemographic correlates of dietary habits for six subgroups of Asian-Americans in California. The 2005 California Health Interview Survey (CHIS) was utilized. A total of 3772 Asian-Americans were included in this study, with the largest subgroup being Chinese (n = 1280; N = 913,798). The outcome variable for this study was dietary behavior defined as consuming five or more fruits and vegetables per day (5-a-day), provided by CHIS. Univariate and multivariable regression analyses were conducted accounting for complex survey design. Being a female (Chinese, Filipina, Korean, and Vietnamese), not being married (Chinese), not being a college graduate (Chinese), living in poverty (South Asian), and speaking only English language at home (Chinese and Japanese) were associated with higher odds of not meeting a 5-a-day requirement. Results highlighted several sociodemographic correlates to not meeting 5-a-day requirement among six Asian-American subgroups. Targeted health promotion measures for such at-risk groups should be implemented to improve dietary practices.

  9. Double-Eyelid Surgery Using Septoaponeurosis Junctional Thickening Results in Dynamic Fold in Asians

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    Hong Seok Kim, MD, PhD

    2013-05-01

    Conclusions: The authors introduce a double-eyelid surgery technique using the SAJT. This SAJT fixation technique creates a dynamic double-eyelid fold. Our study showed a high patient satisfaction rate and that the resulting fold mimics the movement of the congenital supratarsal fold in Asians.

  10. Phantom limb pain relief by contralateral myofascial injection with local anaesthetic in a placebo-controlled study: preliminary results.

    Science.gov (United States)

    Casale, Roberto; Ceccherelli, Francesco; Labeeb, Alaa Abd Elaziz Mohamed; Biella, Gabriele E M

    2009-05-01

    To ascertain the existence of contralateral painful muscle areas mirroring phantom pain and to evaluate the short-term effects of anaesthetic vs saline, injected contra notlaterally to control phantom and phantom limb pain. Double-blinded cross-over study. Inpatients; rehabilitation institute. Eight lower limb amputees with phantom limb pain in the past 6 months. Either 1 ml of 0.25% bupivacaine or 0.9% saline injected alternately in each point with a 28-gauge needle, with 72 h between injections. Main outcome measurePhantom sensation modification and the intensity of phantom limb pain (visual analogue scale) before and after injections. Although present, painful muscle areas in the healthy limb do not mirror the topographical distribution of phantom limb pain. Sixty minutes after the injection, a statistically significant greater relief of phantom limb pain was observed after using local anaesthetic than when using saline injection (p = 0.003). Bupivacaine consistently reduced/abolished the phantom sensation in 6 out of 8 patients. These effects on phantom sensation were not observed after saline injections. Contralateral injections of 1 ml 0.25% bupivacaine in myofascial hyperalgesic areas attenuated phantom limb pain and affected phantom limb sensation. The clinical importance of this treatment method requires further investigation.

  11. Mechanism of Traumatic Brain Injury at Distant Locations After Exposure to Blast Waves: Preliminary Results from Animal and Phantom Experiments.

    Science.gov (United States)

    Nakagawa, Atsuhiro; Ohtani, Kiyonobu; Goda, Keisuke; Kudo, Daisuke; Arafune, Tatsuhiko; Washio, Toshikatsu; Tominaga, Teiji

    2016-01-01

    Purpose Primary blast-induced traumatic brain injury (bTBI) is the least understood of the four phases of blast injury. Distant injury induced by the blast wave, on the opposite side from the wave entry, is not well understood. This study investigated the mechanism of distant injury in bTBI. Materials and Methods Eight 8-week-old male Sprague-Dawley rats were divided into two groups: group 1 served as the control group and did not receive any shock wave (SW) exposure; group 2 was exposed to SWs (12.5 ± 2.5 MPa). Propagation of SWs within a brain phantom was evaluated by visualization, pressure measurement, and numerical simulation. Results Intracerebral hemorrhage near the ignition site and elongation of the distant nucleus were observed, despite no apparent damage between the two locations in the animal experiment. Visualization, pressure measurement, and numerical simulation indicated the presence of complex wave dynamics accompanying a sudden increase in pressure, followed by negative pressure in the phantom experiment. Conclusion A local increase in pressure above the threshold caused by interference of reflection and rarefaction waves in the vicinity of the brain-skull surface may cause distant injury in bTBI.

  12. Realistic computerized human phantoms

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    Zankl, M.; Veit, R.; Petoussi, N.; Mannweiler, E.; Wittmann, A.; Drexler, G.

    1994-10-01

    To estimate the risk resulting from exposures to ionizing radiation, the organ and tissue doses should be assessed. A convenient method is the calculation of these doses using representations of the human body, called models or phantoms, together with computer codes simulating the transport of radiation in the body. Most commonly used are mathematical phantoms whose external and internal volumes are defined by simple geometric bodies. More recently, phantoms constructed from computed tomographic data of real persons were introduced as an improvement. These phantoms present advantages concerning the location and shape of the organs, in particular the hard bone and bone marrow, whose distribution can be assessed with high resolution. So far, three of these phantoms were constructed at the GSF, a fourth is under process. The construction technique is described, and some calculational results of organ doses due to external photon irradiation are presented.

  13. Semi-robotic 6 degree of freedom positioning for intracranial high precision radiotherapy; first phantom and clinical results

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    Flentje Michael

    2010-05-01

    Full Text Available Abstract Background To introduce a novel method of patient positioning for high precision intracranial radiotherapy. Methods An infrared(IR-array, reproducibly attached to the patient via a vacuum-mouthpiece(vMP and connected to the table via a 6 degree-of-freedom(DoF mechanical arm serves as positioning and fixation system. After IR-based manual prepositioning to rough treatment position and fixation of the mechanical arm, a cone-beam CT(CBCT is performed. A robotic 6 DoF treatment couch (HexaPOD™ then automatically corrects all remaining translations and rotations. This absolute position of infrared markers at the first fraction acts as reference for the following fractions where patients are manually prepositioned to within ± 2 mm and ± 2° of this IR reference position prior to final HexaPOD-based correction; consequently CBCT imaging is only required once at the first treatment fraction. The preclinical feasibility and attainable repositioning accuracy of this method was evaluated on a phantom and human volunteers as was the clinical efficacy on 7 pilot study patients. Results Phantom and volunteer manual IR-based prepositioning to within ± 2 mm and ± 2° in 6DoF was possible within a mean(± SD of 90 ± 31 and 56 ± 22 seconds respectively. Mean phantom translational and rotational precision after 6 DoF corrections by the HexaPOD was 0.2 ± 0.2 mm and 0.7 ± 0.8° respectively. For the actual patient collective, the mean 3D vector for inter-treatment repositioning accuracy (n = 102 was 1.6 ± 0.8 mm while intra-fraction movement (n = 110 was 0.6 ± 0.4 mm. Conclusions This novel semi-automatic 6DoF IR-based system has been shown to compare favourably with existing non-invasive intracranial repeat fixation systems with respect to handling, reproducibility and, more importantly, intra-fraction rigidity. Some advantages are full cranial positioning flexibility for single and fractionated IGRT treatments and possibly increased patient

  14. Result of Proficiency Test and Comparison of Accuracy Using a European Spine Phantom among the Three Bone Densitometries.

    Science.gov (United States)

    Park, Ae Ja; Choi, Jee-Hye; Kang, Hyun; Park, Ki Jeong; Kim, Ha Young; Kim, Seo Hwa; Kim, Deog-Yoon; Park, Seung-Hwan; Ha, Yong-Chan

    2015-05-01

    Although dual energy X-ray absorptiometry (DXA) is known to standard equipment for bone mineral density (BMD) measurements. Different results of BMD measurement using a number of different types of devices are difficult to use clinical practice. The purpose of this study was to evaluate discrepancy and standardizations of DXA devices from three manufactures using a European Spine Phantom (ESP). We calculated the accuracy and precision of 36 DXA devices from three manufacturers (10 Hologic, 16 Lunar, and 10 Osteosys) using a ESP (semi-anthropomorphic). The ESP was measured 5 times on each equipment without repositioning. Accuracy was assessed by comparing BMD (g/cm(2)) values measured on each device with the actual value of the phantom. Precision was assessed by the coefficient of variation (CVsd). Lunar devices were, on average, 22%, 8.3%, and 5% overestimation for low (L1) BMD values, medium (L2), and high (L3) BMD values. Hologic devices were, on average, 6% overestimation for L1 BMD, and 5% and 6.2% underestimation for L2 and L3 BMD values. Osteosys devices was, on average, 12.7% (0.063 g/cm(2)), 6.3% (0.062 g/cm(2)), and 5% (0.075 g/cm(2)) underestimation for L1, L2, and L3, respectively. The mean CVsd for L1-L3 BMD were 0.01%, 0.78%, and 2.46% for Lunar, Hologic, and Osteosys devices respectively. The BMD comparison in this study demonstrates that BMD result of three different devices are significant different between three devices. Differences of BMD between three devices are necessary to BMD standardization.

  15. Association between Acculturation and Binge Drinking among Asian-Americans: Results from the California Health Interview Survey

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    Monideepa B. Becerra

    2013-01-01

    Full Text Available Objective. Evaluate the association between acculturation and binge drinking among six Asian-American subgroups. Methods. A cross-sectional analysis of public access adult portion of 2007, 2009, and 2011/2012 California Health Interview Survey data was conducted. Univariate and multivariable logistic regression analyses were utilized with any binge drinking in the past year as the outcome variable and language spoken at home and time in USA as proxy measures of acculturation. Results. A total of 1,631 Asian-Americans (N=665,195 were identified as binge drinkers. Binge drinking was positively associated with being first generation South Asian (OR=3.05, 95% CI=1.55, 5.98 and monolingual (English only Vietnamese (OR=3.00; 95% CI=1.58, 5.70, especially among females. Other factors associated with increased binge drinking were being female (Chinese only, not being current married (South Asian only, and being an ever smoker (all subgroups except South Asians. Conclusion. First generation South Asians and linguistically acculturated Vietnamese, especially females, are at an increased risk of binge drinking. Future studies and preventive measures should address the cultural basis of such health risk behaviors among Asian-American adults.

  16. Human phantom

    CERN Multimedia

    CERN PhotoLab

    1973-01-01

    This human phantom has been received by CERN on loan from the State Committee of the USSR for the Utilization of Atomic Energy. It is used by the Health Physics Group to study personel radiation doses near the accelerators.

  17. Phantom Pain

    Science.gov (United States)

    ... 16, 2014. Phantom pain Symptoms & causes Diagnosis & treatment Advertisement Mayo Clinic does not endorse companies or products. ... a Job Site Map About This Site Twitter Facebook Google YouTube Pinterest Mayo Clinic is a not- ...

  18. Optical imaging of alpha emitters: simulations, phantom, and in vivo results.

    Science.gov (United States)

    Boschi, Federico; Meo, Sergio Lo; Rossi, Pier Luca; Calandrino, Riccardo; Sbarbati, Andrea; Spinelli, Antonello E

    2011-12-01

    There has been growing interest in investigating both the in vitro and in vivo detection of optical photons from a plethora of beta emitters using optical techniques. In this paper we have investigated an alpha particle induced fluorescence signal by using a commercial CCD-based small animal optical imaging system. The light emission of a (241)Am source was simulated using GEANT4 and tested in different experimental conditions including the imaging of in vivo tissue. We believe that the results presented in this work can be useful to describe a possible mechanism for the in vivo detection of alpha emitters used for therapeutic purposes.

  19. [Capsaicin 8 % cutaneous patches for phantom limb pain. Results from everyday practice (non-interventional study)].

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    Kern, K-U; Baust, H; Hofmann, W; Holzmüller, R; Maihöfner, C; Heskamp, M-L

    2014-08-01

    Post amputation pain presents a challenge for pain physicians and is often detrimental to the patient's quality of life. A prospective 12-week non-interventional study (NIS) was conducted in Germany to obtain data on the effectiveness and safety of capsaicin 8 % cutaneous patches from real life use in patients with peripheral neuropathic pain. For the first time in a subgroup of amputees data on post amputation pain were collected. This article presents the results for patients who suffered from phantom limb pain (PLP), stump pain (SP) and combined phantom limb/stump pain (PLP/SP). The analyses included 21 patients with post amputation pain (PLP: n = 10, SP: n = 4, PLP/SP: n = 7). The mean duration of pain (± standard deviation) was 12.8 ± 13.0 years for PLP, 23.1 ± 29.9 years for SP and 11.0 ± 15.8 years for PLP/SP. A single treatment with capsaicin 8 % cutaneous patches significantly reduced the average pain intensity over the observational period of 12 weeks. The mean numeric pain rating scale (NPRS) baseline score changed by - 2.4 for PLP with a standard error of the mean (SEM) of 0.4 (median: - 2.9, Q1: - 3.5, Q3: - 1.0), - 1.7 for SP (SEM: 0.8, median: - 1.1, Q1: - 2.9, Q3: - 0.5) and - 1.5 for PLP/SP (SEM: 0.6, median: - 2.0, Q1: - 2.3, Q3: 0) during weeks 1-12. The 30 % responder rates (i.e. ≥ 30 % reduction in pain, day 7/14 to week 12) were 70.0 % (PLP), 50.0 % (SP) and 28.6 % (PLP/SP). PLP and PLP/SP patients in particular, benefited from improvements in pain attacks, sleep duration and sleep quality and one patient (PLP/SP) reported an adverse drug reaction (increase of pain). Physicians rated the tolerability of the patch as very good or good in 90.5 % of patients. A poor tolerability was stated for none of the 21 amputees. Of the patients 80 % for PLP and 50 % for both SP and PLP/SP expressed the wish to receive retreatment with capsaicin 8 % patches. Capsaicin 8

  20. Dose Conversion Coefficients Based on Taiwanese Reference Phantoms and Monte Carlo Simulations for Use in External Radiation Protection.

    Science.gov (United States)

    Chang, Shu-Jun; Hsu, Jui-Ting; Hung, Shih-Yen; Liu, Yan-Lin; Jiang, Shiang-Huei; Wu, Jay

    2017-05-01

    Reference phantoms are widely applied to evaluate the radiation dose for external exposure. However, the frequently used reference phantoms are based on Caucasians. Dose estimation for Asians using a Caucasian phantom can result in significant errors. This study recruited 40 volunteers whose body sizes are close to the average Taiwanese population. Magnetic resonance imaging was performed to obtain the organ volume for construction of the Taiwanese reference man (TRM) and Taiwanese reference woman (TRW). The dose conversion coefficients (DCC) resulting from photo beams in anterior-posterior, posterior-anterior, right-lateral, left-lateral, and isotropic irradiation geometries were estimated. In the anterior-posterior geometry, the mean DCC differences among organs between the TRM and ORNL phantom at 0.1, 1, and 10 MeV were 7.3%, 5.8%, and 5.2%, respectively. For the TRW, the mean differences from the ORNL phantom at the three energies were 10.6%, 7.4%, and 8.3%. The DCCs of the Taiwanese reference phantoms and the ORNL phantom presented similar trends in other geometries. The torso size of the phantom and the mass and geometric location of the organ have a significant influence on the DCC. The Taiwanese reference phantoms can be used to establish dose guidelines and regulations for radiation protection from external exposure.

  1. The impact of audio-visual biofeedback on 4D PET images: Results of a phantom study

    OpenAIRE

    Yang, Jaewon; Yamamoto, Tokihiro; Cho, Byungchul; Seo, Youngho; Keall, Paul J.

    2012-01-01

    Purpose: Irregular breathing causes motion blurring artifacts in 4D PET images. Audiovisual (AV) biofeedback has been demonstrated to improve breathing regularity. To investigate the hypothesis that, compared with free breathing, motion blurring artifacts are reduced with AV biofeedback, the authors performed the first experimental phantom-based quantification of the impact of AV biofeedback on 4D PET image quality.

  2. Results of the third reproductive assessment survey of North American Asian (Elephas maximus) and African (Loxodonta africana) female elephants.

    Science.gov (United States)

    Dow, T L; Holásková, I; Brown, J L

    2011-01-01

    A written survey assessed reproductive status of female Asian and African elephants in AZA/SSP facilities in 2008, and data were compared to surveys conducted in 2002 and 2005. Results showed that ovarian acyclicity rates across the surveys remained unchanged for Asian (13.3, 10.9 and 11.1%) and African (22.1, 31.2 and 30.5%) elephants, respectively (P > 0.05), but were higher overall for African compared to Asian elephants (P elephants with irregular cycles (14.3 and 15.8%) and irregular + no cycles (25.4 and 46.4%) was similar to 2005 (7.6 and 11.8%; 18.5 and 43.0%), but were increased compared to 2002 (2.6 and 5.2%; 16.0 and 27.3%), respectively (P elephants compared to females at facilities with no male, respectively. Cyclicity rates were higher for Asian (86.8 vs. 65.2%) and African (67.9 vs. 56.7%) elephants managed in free compared to protected contact programs (P 0.05). In summary, incidence of ovarian cycle problems continues to predominantly affect African elephants. Although percentages of acyclicity did not increase between 2005 and 2008, 42.2% Asian and 30.2% African females were no longer being hormonally monitored; thus, reproductive cycle abnormalities could be worse than current data suggest. © 2011 Wiley Periodicals, Inc.

  3. The British Asian Community Eye Study: Outline of results on the prevalence of eye disease in British Asians with origins from the Indian subcontinent

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    Abdul Rauf

    2013-01-01

    Full Text Available Background: Asians from the Indian Subcontinent form the largest ethnic minority in the United Kingdom. Data on the prevalence of visually-impairing eye conditions in this population are vital for planning eye health care services. Materials and Methods: This survey was based in the two London boroughs with the largest Asian populations. Subjects originating from the Indian Subcontinent were identified from GP practice records. All subjects were asked about demographic details and were given a full ophthalmological examination. The severity of cataract, glaucoma, diabetic retinopathy, and age-related maculopathy was recorded. Blindness was defined as logMAR visual acuity of 0.99 (Snellen equivalence 20/200 in the better eye or worse, ′low vision′ was defined as Snellen equivalence of 20/63 or worse (logMAR 0.5 or higher, and visual impairment was defined as visual acuity worse than 20/40. Results: The median age was 56 years. Two hundred and eighty four subjects did not attend for eye examination. Of the 922 examined, 128 subjects (13.9% were ′visually impaired,′ 39 (4.2% had ′low vision,′ and 6 (0.7% were bilaterally blind. The overall prevalence of cataract, open-angle glaucoma, age-related macular degeneration, and diabetic retinopathy were 77%, 1.0%, 8.7%, and 8.8%, respectively. Conclusion: Visual impairment rates amongst Asians seem to be similar to Caucasian populations in the UK. The prevalence of cataract and diabetic retinopathy is higher, while the risk of ARMD and OAG are comparable. In view of the high cataract prevalence, a more detailed assessment of the visual profile and factors limiting healthcare accessibility in this community are needed.

  4. Mapping cropland parameters - Results from the Central Asian Water (CAWa) project

    Science.gov (United States)

    Conrad, Christopher; Löw, Fabian; Unger-Shayesteh, Katy

    2014-05-01

    The CAWa (Central Asian Water) project aims at providing a sound scientific basis for trans-national water resources management in Central Asia (see www.cawa-project.net). The planned activities involve a network of scientific institutions all over Central Asia. They produce joint scientific results as well as pass down up-to-date scientific methods and approaches. The German Research Centre for Geosciences in Potsdam (GFZ) has taken over the project coordination. The Department of Remote Sensing, Würzburg University, associated with the German Aerospace Centre (DLR) is one of the project partners. Its major research activities focus on analysing information on land use and agricultural production and their changes in space and time from remote sensing data, focusing on the irrigated land in Central Asia. Some of the research topics include cropland mapping (e.g. crop classification and creation of agricultural field cadastre), crop production monitoring (yield), drought monitoring, and mapping and monitoring of spatial cropland extent. Detection of marginal land or agricultural land abandonment, a widespread phenomenon in this region that has strong socio-economic and ecological consequences, is another research focus. The methods and results demonstrate the value of remote sensing technologies to supporting regional decision makers and planners for an improved and sustainable land and water resource management.

  5. Why do Asian-American women have lower rates of breast conserving surgery: results of a survey regarding physician perceptions

    Directory of Open Access Journals (Sweden)

    Allen Laura J

    2009-07-01

    Full Text Available Abstract Background US Asian women with early-stage breast cancer are more likely to receive a modified radical mastectomy (MRM than White women, contrary to clinical recommendations regarding breast conserving treatment (BCT. Methods We surveyed physicians regarding treatment decision-making for early-stage breast cancer, particularly as it applies to Asian patients. Physicians were identified through the population-based Greater Bay Area Cancer Registry. Eighty (of 147 physicians completed a questionnaire on sociodemographics, professional training, clinical practices, and perspectives on the treatment decision-making processes. Results The most important factors identified by physicians in the BCT/MRM decision were clinical in nature, including presence of multifocal disease (86% identified this as being an important factor for selecting MRM, tumor size (71% for MRM, 78% for BCT, cosmetic result (74% for BCT, and breast size (50% for MRM, 55% for BCT. The most important reasons cited for the Asian treatment patterns were patient attitudes toward not needing to preserve the breast (53%, smaller breast sizes (25%, and fear and cultural beliefs (12%. Conclusion These survey results suggest that physicians perceive major roles of both clinical and cultural factors in the BCT/MRM decision, but cultural factors may be more relevant in explaining surgical treatment patterns among Asians.

  6. Multi-Modality Phantom Development

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. Quality control within the multicentre perfusion CT study of primary colorectal cancer (PROSPeCT): results of an iodine density phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Maria; Honey, Ian [Trust, Medical Physics Department, Guy' s and St. Thomas' NHS Foundation, London (United Kingdom); Goh, Vicky [King' s College London, St Thomas' Hospital, Division of Imaging Sciences and Biomedical Engineering, London (United Kingdom); Beggs, Shaun [Bradford Teaching Hospitals NHS Foundation Trust, Radiation Physics Services, Bradford (United Kingdom); Bridges, Andrew; Wayte, Sarah [Radiology Physics University Hospitals Coventry and Warwickshire NHS Trust, Coventry (United Kingdom); Clewer, Philip [Medical Physics Department, University Hospital Southampton NHS Foundation Trust, Southampton (United Kingdom); Davis, Anne [Portsmouth Hospitals NHS Trust, Medical Physics Department, Portsmouth (United Kingdom); Foy, Trevelyan [Royal Cornwall Hospital NHS Trust, Medical Physics Department, Truro (United Kingdom); Fuller, Karen [Sheffield Teaching Hospitals NHS Foundation Trust, Medical Physics Department, Sheffield (United Kingdom); George, Jennifer [University Hospital of North Staffordshire NHS Trust, Medical Physics Department, Stoke-on-Trent (United Kingdom); Higginson, Antony [Portsmouth Hospitals NHS Trust, Department of Radiology, Portsmouth (United Kingdom); Iball, Gareth [Leeds Teaching Hospitals NHS Trust, Department of Medical Physics and Engineering, Leeds (United Kingdom); Mutch, Steve [Oxford University Hospitals NHS Trust, Radiation Physics and Protection Department, Oxford (United Kingdom); Neil, Shellagh; Sutton, David [NHS Tayside, Medical Physics Department, Dundee, Scotland (United Kingdom); Rivett, Cat [Plymouth Hospitals NHS Trust, Clinical and Radiation Physics, Plymouth (United Kingdom); Slater, Andrew [Oxford University Hospitals NHS Trust, Department of Radiology, Oxford (United Kingdom); Weir, Nick [Queen' s Medical Research Institute, Clinical Research Imaging Centre, Edinburgh, Scotland (United Kingdom); Collaboration: on behalf of the PROSPeCT Investigators

    2014-09-15

    To assess the cross-centre consistency of iodine enhancement, contrast-to-noise ratio and radiation dose in a multicentre perfusion CT trial of colorectal cancer. A cylindrical water phantom containing different iodine inserts was examined on seven CT models in 13 hospitals. The relationship between CT number (Hounsfield units, HU) and iodine concentration (milligrams per millilitre) was established and contrast-to-noise ratios (CNRs) calculated. Radiation doses (CTDI{sub vol}, DLP) were compared across all sites. There was a linear relationship between CT number and iodine density. Iodine enhancement varied by a factor of at most 1.10, and image noise by at most 1.5 across the study sites. At an iodine concentration of 1 mg ml{sup -1} and 100 kV, CNRs ranged from 3.6 to 4.8 in the 220-mm phantom and from 1.4 to 1.9 in the 300-mm phantom. Doses varied by a factor of at most 2.4, but remained within study dose constraints. Iterative reconstruction algorithms did not alter iodine enhancement but resulted in reduced image noise by a factor of at most 2.2, allowing a potential dose decrease of at most 80 % compared to filtered back projection (FBP). Quality control of CT performance across centres indicates that CNR values remain relatively consistent across all sites, giving acceptable image quality within the agreed dose constraints. (orig.)

  8. The East Asian Summer Monsoon at mid-Holocene: results from PMIP3 simulations

    Directory of Open Access Journals (Sweden)

    W. Zheng

    2013-02-01

    Full Text Available Ten Coupled General Circulation Models (CGCMs participated in the third phase of Paleoclimate Modelling Intercomparison Project (PMIP3 are assessed for the East Asian Summer Monsoon (EASM in both the pre-Industrial (PI, 0 ka and mid-Holocene (MH, 6 ka simulations. Results show that the PMIP3 model median captures well the large-scale characteristics of the EASM, including the two distinct features of the Meiyu rainbelt and the stepwise meridional displacement of the monsoonal rainbelt. At mid-Holocene, the PMIP3 model median shows significant warming (cooling during boreal summer (winter over Eurasia continent that are dominated by the changes of insolation. However, the PMIP3 models fail to simulate a warmer annual mean and winter surface air temperature (TAS over eastern China as derived from proxy records. The EASM at MH are featured by the changes of large-scale circulation over Eastern China while the changes of precipitation are not significant over its sub-domains of the Southern China and the lower reaches of Yangzi River. The inter-model differences for the monsoon precipitation can be associated with different configurations of the changes in large-scale circulation and the water vapour content, of which the former determines the sign of precipitation changes. The large model spread for the TAS over Tibetan Plateau has a positive relationship with the precipitation in the lower reaches of Yangzi River, yet this relationship does not apply to those PMIP3 models in which the monsoonal precipitation is more sensitive to the changes of large-scale circulation. Except that the PMIP3 model median captured the warming of annual mean TAS over Tibetan Plateau, no significant improvements can be concluded when compared with the PMIP2 models results.

  9. Millimeter wave silicon micromachined waveguide probe as an aid for skin diagnosis--results of measurements on phantom material with varied water content.

    Science.gov (United States)

    Dancila, D; Augustine, R; Töpfer, F; Dudorov, S; Hu, X; Emtestam, L; Tenerz, L; Oberhammer, J; Rydberg, A

    2014-02-01

    More than 2 million cases of skin cancer are diagnosed annually in the United States, which makes it the most common form of cancer in that country. Early detection of cancer usually results in less extensive treatment and better outcome for the patient. Millimeter wave silicon micromachined waveguide probe is foreseen as an aid for skin diagnosis, which is currently based on visual inspection followed by biopsy, in cases where the macroscopical picture raises suspicion of malignancy. Demonstration of the discrimination potential of tissues of different water content using a novel micromachined silicon waveguide probe. Secondarily, the silicon probe miniaturization till an inspection area of 600 × 200 μm2, representing a drastic reduction by 96.3% of the probing area, in comparison with a conventional WR-10 waveguide. The high planar resolution is required for histology and early-state skin-cancer detection. To evaluate the probe three phantoms with different water contents, i.e. 50%, 75% and 95%, mimicking dielectric properties of human skin were characterized in the frequency range of 95-105 GHz. The complex permittivity values of the skin are obtained from the variation in frequency and amplitude of the reflection coefficient (S11), measured with a Vector Network Analyzer (VNA), by comparison with finite elements simulations of the measurement set-up, using the commercially available software, HFSS. The expected frequency variation is calculated with HFSS and is based on extrapolated complex permittivities, using one relaxation Debye model from permittivity measurements obtained using the Agilent probe. Millimeter wave reflection measurements were performed using the probe in the frequency range of 95-105 GHz with three phantoms materials and air. Intermediate measurement results are in good agreement with HFSS simulations, based on the extrapolated complex permittivity. The resonance frequency lowers, from the idle situation when it is probing air

  10. A comparative study on patient specific absolute dosimetry using slab phantom, acrylic body phantom and goat head phantom

    Directory of Open Access Journals (Sweden)

    Om Prakash Gurjar

    2015-01-01

    Full Text Available Purpose: To compare the results of patient specific absolute dosimetry using slab phantom, acrylic body phantom and goat head phantom. Methods: Fifteen intensity modulated radiotherapy (IMRT plans already planned on treatment planning system (TPS for head-and-neck cancer patients were exported on all three kinds of phantoms viz. slab phantom, acrylic body phantom and goat head phantom, and dose was calculated using anisotropic analytic algorithm (AAA. All the gantry angles were set to zero in case of slab phantom while set to as it is in actual plan in case of other two phantoms. All the plans were delivered by linear accelerator (LA and dose for each plan was measured by 0.13 cc ion chamber. The percentage (% variations between planned and measured doses were calculated and analyzed. Results: The mean % variations between planned and measured doses of all IMRT quality assurance (QA plans were as 0.65 (Standard deviation (SD: 0.38 with confidence limit (CL 1.39, 1.16 (SD: 0.61 with CL 2.36 and 2.40 (SD: 0.86 with CL 4.09 for slab phantom, acrylic head phantom and goat head phantom respectively. Conclusion: Higher dose variations found in case of real tissue phantom compare to results in case of slab and acrylic body phantoms. The algorithm AAA does not calculate doses in heterogeneous medium as accurate as it calculates in homogeneous medium. Therefore the patient specific absolute dosimetry should be done using heterogeneous phantom mimicking density wise as well as design wise to the actual human body.  

  11. A hydrophobic gel phantom for study of thermochemical ablation: initial results using a weak acid and weak base.

    Science.gov (United States)

    Misselt, Andrew J; Edelman, Theresa L; Choi, Jeung H; Bischof, John C; Cressman, Erik N K

    2009-10-01

    To develop a model for study of exothermic chemical reactions potentially useful for tissue ablation. Seven gelatins ranging from 0.5% to 30% wt/vol with and without 15% or 30% caps and several commercial gels were evaluated. Baseline temperature measurements were taken. Acetic acid and ammonium hydroxide were sequentially injected over periods of 10-15 seconds in 1-mL aliquots, forming a discrete aqueous reaction chamber. Congo red pH indicator was included to assess the reaction. A thermocouple allowed data collection at completion of injection and every 15 seconds for 5 minutes. Injections were performed in triplicate, and average temperatures for each time point were reported. Gelatins fractured or refluxed even at the lowest concentrations tested. Most commercial gels proved too viscous and likewise led to reflux along the needle tract. A mineral oil-based gel was selected because of its ability to form a chamber without reflux or fracture and its clear colorless character, hydrophobic nature, chemical stability, viscosity, specific gravity, and cost. Temperatures during the first 60 seconds of the neutralization reaction showed an immediate increase that correlated well with concentration. The oil gel phantom is a safe, useful, readily available, inexpensive model to study mixing behaviors and maximum heating potentials for reactions that may prove useful in thermochemical tissue ablation for oncologic interventions. Measurable temperature changes occurred even at the lowest concentrations, and higher concentrations produced a greater release of heat energy.

  12. Causes and consequences of gestational diabetes in South Asians living in Canada: results from a prospective cohort study

    Science.gov (United States)

    Anand, Sonia S.; Gupta, Milan; Teo, Koon K.; Schulze, Karleen M.; Desai, Dipika; Abdalla, Nora; Zulyniak, Michael; de Souza, Russell; Wahi, Gita; Shaikh, Mateen; Beyene, Joseph; de Villa, Eileen; Morrison, Katherine; McDonald, Sarah D.; Gerstein, Hertzel

    2017-01-01

    Background: The reasons for the increased risk of gestational diabetes among South Asian women are not well understood. We sought to identify the determinants of gestational diabetes and its impact on newborn health in a prospective birth cohort of South Asian women and their babies. Methods: As part of the South Asian Birth Cohort (START) prospective birth cohort study in Ontario, we recruited 1012 South Asian women with singleton pregnancies in the second trimester of pregnancy between July 11, 2011, and Nov. 10, 2015. We collected health information and physical measurements and administered an oral glucose tolerance test. Birth weight and skinfold thickness measurements were obtained from their newborns, and cord blood glucose and insulin levels were measured. Results: The incidence of gestational diabetes was 36.3% (95% confidence interval [CI] 33.3%-39.3%); the age-standardized rate was 40.7%. Factors associated with gestational diabetes included maternal age (odds ratio [OR] 1.08 [95% CI 1.04-1.12]), family history of diabetes (OR 1.65 [95% CI 1.26-2.17]), prepregnancy weight (OR 1.025 [95% CI 1.01-1.04]) and low diet quality (OR 1.57 [95% CI 1.16-2.12]). Maternal height was protective against gestational diabetes (OR 0.97 [95% CI 0.95-0.99]). The population attributable risk due to prepregnancy body mass index and low diet quality was 37.3%. Compared to newborns of women without gestational diabetes, those of women with gestational diabetes had a significantly higher birth weight (3267 [standard error (SE) 23] g v. 3181 [SE 17] g, p = 0.005), greater skinfold thickness (11.7 [SE 0.1] mm v. 11.2 [SE 0.1] mm, p = 0.007) and lower insulin sensitivity (glucose/insulin ratio 0.092 [SE 0.009] mmol/pmol v. 0.129 [SE 0.006] mmol/pmol, p = 0.001). Interpretation: The modifiable risk factors of prepregnancy weight and low diet quality accounted for 37% of the population attributable risk of gestational diabetes in our cohort. Intervention studies to lower

  13. Micro-scale finite element modeling of ultrasound propagation in aluminum trabecular bone-mimicking phantoms: A comparison between numerical simulation and experimental results.

    Science.gov (United States)

    Vafaeian, B; Le, L H; Tran, T N H T; El-Rich, M; El-Bialy, T; Adeeb, S

    2016-05-01

    The present study investigated the accuracy of micro-scale finite element modeling for simulating broadband ultrasound propagation in water-saturated trabecular bone-mimicking phantoms. To this end, five commercially manufactured aluminum foam samples as trabecular bone-mimicking phantoms were utilized for ultrasonic immersion through-transmission experiments. Based on micro-computed tomography images of the same physical samples, three-dimensional high-resolution computational samples were generated to be implemented in the micro-scale finite element models. The finite element models employed the standard Galerkin finite element method (FEM) in time domain to simulate the ultrasonic experiments. The numerical simulations did not include energy dissipative mechanisms of ultrasonic attenuation; however, they expectedly simulated reflection, refraction, scattering, and wave mode conversion. The accuracy of the finite element simulations were evaluated by comparing the simulated ultrasonic attenuation and velocity with the experimental data. The maximum and the average relative errors between the experimental and simulated attenuation coefficients in the frequency range of 0.6-1.4 MHz were 17% and 6% respectively. Moreover, the simulations closely predicted the time-of-flight based velocities and the phase velocities of ultrasound with maximum relative errors of 20 m/s and 11 m/s respectively. The results of this study strongly suggest that micro-scale finite element modeling can effectively simulate broadband ultrasound propagation in water-saturated trabecular bone-mimicking structures. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Accelerated partial breast irradiation in an Asian population: dosimetric findings and preliminary results of a multicatheter interstitial program

    Directory of Open Access Journals (Sweden)

    Koh YV

    2016-09-01

    Full Text Available Yaling Vicky Koh,1 Poh Wee Tan,1 Shaik Ahmad Buhari,2 Philip Iau,2 Ching Wan Chan,2 Liang Shen,3 Sing Huang Tan,4 Johann I-Hsiung Tang1 1Department of Radiation Oncology, National University Cancer Institute Singapore, 2Department of Surgery, National University Hospital, 3Department of Medicine, Biostatistics Unit, National University of Singapore, 4Department of Medical Oncology, National University Cancer Institute Singapore, Singapore Introduction: Accelerated partial breast irradiation (APBI using the multicatheter method has excellent cosmesis and low rates of long-term toxicity. However, there are few studies looking at the feasibility of this procedure and the outcomes in an Asian population. This study aims to look at outcomes at our hospital.Methods: We identified 121 patients treated with APBI at our center between 2008 and 2014. The median follow-up for our patient group was 30 months (range 3.7–66.5. The prescribed dose per fraction was 3.4 Gy in 10 fractions. In this study population, 71% of the patients were Chinese while 15% (n=19 were of other Asian ethnicity.Results: In this study, the median breast volume was 850 cc (range 216–2,108 with 59.5% (n=72 patients with a breast volume of <1,000 cc. The average planning target volume was 134 cc (range 28–324. The number of catheters used ranged from 8 to 25 with an average of 18 catheters used per patient. We achieved an average dose homogeneity index of 0.76 in our patients. The average D90(% was 105% and the average D90(Gy was 3.6 Gy per fraction. The median volume receiving 100% of the prescribed dose (V100 was 161.7 cc (range 33.9–330.1, 150% of the prescribed dose (V150 and 200% of the prescribed dose (V200 was 39.4 cc (range 14.6–69.6 and 14.72 cc (range 6.48–22.25, respectively. Our dosimetric outcomes were excellent even in patients with breast volume under 1,000 cc. There were no cases of grade 3 skin toxicity or acute pneumonitis. Two patients had a

  15. Screening and management of hypothyroidism in pregnancy: results of an Asian survey.

    Science.gov (United States)

    Azizi, Fereidoun; Amouzegar, Atieh; Mehran, Ladan; Alamdari, Shahram; Subekti, Imam; Vaidya, Bijay; Poppe, Kris; San Luis, Teofilo; Akamizu, Takashi

    2014-01-01

    Maternal hypothyroidism in pregnancy is associated with several adverse outcomes. The American Thyroid Association and the Endocrine Society Guidelines for the management of thyroid diseases in pregnancy were published in 2011 and 2012, respectively; however, impact of the guidelines in routine clinical practice is unknown. We therefore carried out a survey to study current practices in the screening and management of hypothyroidism in pregnancy. We collected completed questionnaire survey based on clinical case scenarios from 321 members of the Asia-Oceania Thyrpid Association (AOTA). Responses from 310 clinician members (from 21 Asian countries) were analyzed. For a woman with hypothyroidism planning pregnancy, 54% favored testing thyroid function before adjusting the dose, whilst 32% recommended increasing the dose of L-thyroxine (L-T₄) as soon as pregnancy is confirmed. For a pregnant woman with newly diagnosed overt hypothyroidism, most responders initiated a full dose of L-T₄. One half of responders used serum TSH and free T₄ to monitor the dose of L-T₄. Although the target of thyroid function tests that responders aimed to achieve with L-T₄ was inconsistent, but a majority aim to keep TSH within recommended trimester specific range. Twenty-one % responders or their institutions screened all pregnant women for thyroid dysfunction, 66% performed targeted screening of only the high-risk group, whilst 13% did not carry out systemic screening. Majority of responders practices within recommendations of major professional societies; however, there is wide variation in the clinical practice in the treatment and screening of hypothyroidism during pregnancy in Asia.

  16. Psychophysical correlates of phantom limb experience.

    Science.gov (United States)

    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

  17. Neural correlates of evoked phantom limb sensations.

    Science.gov (United States)

    Andoh, J; Diers, M; Milde, C; Frobel, C; Kleinböhl, D; Flor, H

    2017-05-01

    Previous work showed the existence of changes in the topographic organization within the somatosensory cortex (SI) in amputees with phantom limb pain, however, the link between nonpainful phantom sensations such as cramping or tingling or the percept of the limb and cortical changes is less clear. We used functional magnetic resonance imaging (fMRI) in a highly selective group of limb amputees who experienced inducible and reproducible nonpainful phantom sensations. A standardized procedure was used to locate body sites eliciting phantom sensations in each amputee. Selected body sites that could systematically evoke phantom sensations were stimulated using electrical pulses in order to induce phasic phantom sensations. Homologous body parts were also stimulated in a group of matched controls. Activations related to evoked phantom sensations were found bilaterally in SI and the intraparietal sulci (IPS), which significantly correlated with the intensity of evoked phantom sensations. In addition, we found differences in intra- and interhemispheric interaction between amputees and controls during evoked phantom sensations. We assume that phantom sensations might be associated with a functional decoupling between bilateral SI and IPS, possibly resulting from transcallosal reorganization mechanisms following amputation. Copyright © 2017. Published by Elsevier B.V.

  18. Continuum beliefs and stigmatising beliefs about mental illness: results from an Asian community survey.

    Science.gov (United States)

    Subramaniam, Mythily; Abdin, Edimansyah; Picco, Louisa; Shahwan, Shazana; Jeyagurunathan, Anitha; Vaingankar, Janhavi Ajit; Chong, Siow Ann

    2017-04-05

    To establish the prevalence and correlates of continuum beliefs for five mental illnesses in a multiethnic population and to explore its association with stigma. A community-based, cross-sectional study. A national study in a multiethnic Asian country. A comprehensive study of 3006 Singapore residents (Singapore citizens and permanent residents) aged 18-65 years who were living in Singapore at the time of the survey. Parameters assessed included belief in a continuum of symptom experience, stigma dimensions and causal beliefs in mental illness. Statistical analyses included descriptive statistics and multiple linear regression (MLR). About half of the population indicated agreement with a continuum of symptoms for depression (57.9%) and dementia (46.8%), whereas only about one in three respondents agreed with it for alcohol abuse (35.6%), schizophrenia (32.7%) and obsessive-compulsive disorder (OCD) (36.8%). MLR analyses revealed that students (β=0.28; 95% CI 0.05 to 0.50; p=0.018) and those who were unemployed (β=0.60; 95% CI 0.26 to 0.95; p=0.001) (vs employed) as well as those who had previous contact with people with mental illness (β = 0.31; 95% CI 0.18 to 0.45; pfamily arguments, difficulties at work or financial difficulties to be a cause for mental illness (β=0.43; 95% CI 0.13 to 0.73; p=0.005) were associated with a higher belief in a continuum of symptom experience. Continuum beliefs were related to lower desire for social distance in alcohol abuse, OCD and schizophrenia; however, they were associated with higher scores on 'weak-not-sick' stigma dimension in dementia and schizophrenia. Perceiving that a person with a mental illness is similar to themselves may reduce social distancing by the public. Thus, the approach may lend itself well to public education aimed at reducing stigma. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise

  19. [Phantom limb pain: from physiopathology to prevention].

    Science.gov (United States)

    Roullet, S; Nouette-Gaulain, K; Brochet, B; Sztark, F

    2009-05-01

    First described in 1545, phantom limb pain is a frequent complication after limb amputation, described by 60 to 85% of amputees. Stump pain, phantom limb sensation and phantom limb pain are often combined. Physiopathology is complex and peripheral, medullar and cortical mechanisms are combined. Pharmacological preventive treatments as well as regional anaesthesia techniques have equivalent results. Such treatments must be investigated more precisely as postoperative rehabilitation of amputees mostly depends on pain relief.

  20. Generational differences in fast food intake among South-Asian Americans: results from a population-based survey.

    Science.gov (United States)

    Becerra, Monideepa B; Herring, Patti; Marshak, Helen Hopp; Banta, Jim E

    2014-12-04

    The goal of this study was to evaluate the association between generational status and fast food consumption among South-Asian Americans. We conducted a secondary analysis of data from the California Health Interview Survey for 2007, 2009, and 2011. After adjusting for control variables, South-Asian Americans of the third generation or more had a fast food intake rate per week 2.22 times greater than first generation South-Asian Americans. Public health practitioners must focus on ways to improve dietary outcomes among this fast-growing ethnic population in the United States.

  1. Comparison of Unmonochromatized Synchrotron Radiation and Conventional X-rays in the Imaging of Mammographic Phantom and Human Breast Specimens: A Preliminary Result

    Science.gov (United States)

    Jung, Haijo; Kim, Eun-Kyung; Hong, Jin-O; Je, Jung Ho; Hwu, Yeukuang; Tsai, Wen-Li; Magaritondo, Giorgio; Yoo, Hyung-Sik

    2005-01-01

    A simple imaging setup based on the principle of coherence-based contrast X-ray imaging with unmonochromatized synchrotron radiation was used for studying mammographic phantom and human breast specimens. The use of unmonochromatized synchrotron radiation simplifies the instrumentation, decreases the cost and makes the procedure simpler and potentially more suitable for clinical applications. The imaging systems consisted of changeable silicon wafer attenuators, a tungsten slit system, a CdWO4 scintillator screen, a CCD (Charge Coupled Device) camera coupled to optical magnification lenses, and a personal computer. In preliminary studies, a spatial resolution test pattern and glass capillary filled with air bubbles were imaged to evaluate the resOolution characteristics and coherence-based contrast enhancement. Both the spatial resolution and image quality of the proposed system were compared with those of a conventional mammography system in order to establish the characteristic advantages of this approach. The images obtained with the proposed system showed a resolution of at least 25 µm on the test pattern with much better contrast, while the images of the capillary filled with air bubbles revealed coherence-based edge enhancement. This result shows that the coherence-based contrast imaging system, which emphasizes the refraction effect from the edge of materials of different refractive indexes, is applicable to imaging studies in fundamental medicine and biology, although further research works will be required before it can be used for clinical applications. PMID:15744811

  2. Comparison of unmonochromatized synchrotron radiation and conventional X-rays in the imaging of mammographic phantom and human breast specimens: a preliminary result.

    Science.gov (United States)

    Jung, Haijo; Kim, Hee-Joung; Kim, Eun-Kyung; Hong, Jin-O; Je, Jung Ho; Hwu, Yeukuang; Tsai, Wen-Li; Magaritondo, Giorgio; Yoo, Hyung-Sik

    2005-02-28

    A simple imaging setup based on the principle of coherence-based contrast X-ray imaging with unmonochromatized synchrotron radiation was used for studying mammographic phantom and human breast specimens. The use of unmonochromatized synchrotron radiation simplifies the instrumentation, decreases the cost and makes the procedure simpler and potentially more suitable for clinical applications. The imaging systems consisted of changeable silicon wafer attenuators, a tungsten slit system, a CdWO4 scintillator screen, a CCD (Charge Coupled Device) camera coupled to optical magnification lenses, and a personal computer. In preliminary studies, a spatial resolution test pattern and glass capillary filled with air bubbles were imaged to evaluate the resOolution characteristics and coherence-based contrast enhancement. Both the spatial resolution and image quality of the proposed system were compared with those of a conventional mammography system in order to establish the characteristic advantages of this approach. The images obtained with the proposed system showed a resolution of at least 25 microm on the test pattern with much better contrast, while the images of the capillary filled with air bubbles revealed coherence-based edge enhancement. This result shows that the coherence-based contrast imaging system, which emphasizes the refraction effect from the edge of materials of different refractive indexes, is applicable to imaging studies in fundamental medicine and biology, although further research works will be required before it can be used for clinical applications.

  3. Intercalibration of in vivo counting systems using an Asian phantom results of a co-ordinated research project 1996-1998

    CERN Document Server

    International Atomic Energ Agency. Vienna

    2003-01-01

    Radioactive materials are used in many industries, and, whenever unsealed radioactive sources are present, intakes of radionuclides by workers can occur. Adequate radiation protection of workers is an essential requirement for the safe and acceptable use of radiation, radioactive materials and nuclear energy. Guidance on the application of the requirements of the International Basis Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (BSS) to occupational protection is given in three interrelated Safety Guides: Occupational Radiation Protection (RS-G-1.1); Assessment of Occupational Exposure due to Intakes of Radionuclides (RS-G-1.2); Assessment of Occupational Exposure due to External Sources of Radiation (RS-G-1.3) published in 1999 and further guidance is given in Safety Reports. Uranium, thorium and transuranic elements such as plutonium and americium are encountered throughout the nuclear fuel cycle and in industry. Radionuclides of these elements have a sig...

  4. Synthetic breast phantoms from patient based eigenbreasts.

    Science.gov (United States)

    Sturgeon, Gregory M; Park, Subok; Segars, William Paul; Lo, Joseph Y

    2017-12-01

    The limited number of 3D patient-based breast phantoms available could be augmented by synthetic breast phantoms in order to facilitate virtual clinical trials (VCTs) using model observers for breast imaging optimization and evaluation. These synthetic breast phantoms were developed using Principal Component Analysis (PCA) to reduce the number of dimensions needed to describe a training set of images. PCA decomposed a training set of M breast CT volumes (with millions of voxels each) into an M-1-dimensional space of eigenvectors, which we call eigenbreasts. Each of the training breast phantoms was compactly represented by the mean image plus a weighted sum of eigenbreasts. The distribution of weights observed from training was then sampled to create new synthesized breast phantoms. The resulting synthesized breast phantoms demonstrated a high degree of realism, as supported by an observer study. Two out of three experienced physicist observers were unable to distinguish between the synthesized breast phantoms and the patient-based phantoms. The fibroglandular density and noise power law exponent of the synthesized breast phantoms agreed well with the training data. Our method extends our series of digital breast phantoms based on breast CT data, providing the capability to generate new, statistically varying ensembles consisting of tens of thousands of virtual subjects. This work represents an important step toward conducting future virtual trials for task-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. © 2017 American Association of Physicists in Medicine.

  5. Pandemic influenza preparedness and health systems challenges in Asia: results from rapid analyses in 6 Asian countries

    Directory of Open Access Journals (Sweden)

    Putthasri Weerasak

    2010-06-01

    Full Text Available Abstract Background Since 2003, Asia-Pacific, particularly Southeast Asia, has received substantial attention because of the anticipation that it could be the epicentre of the next pandemic. There has been active investment but earlier review of pandemic preparedness plans in the region reveals that the translation of these strategic plans into operational plans is still lacking in some countries particularly those with low resources. The objective of this study is to understand the pandemic preparedness programmes, the health systems context, and challenges and constraints specific to the six Asian countries namely Cambodia, Indonesia, Lao PDR, Taiwan, Thailand, and Viet Nam in the prepandemic phase before the start of H1N1/2009. Methods The study relied on the Systemic Rapid Assessment (SYSRA toolkit, which evaluates priority disease programmes by taking into account the programmes, the general health system, and the wider socio-cultural and political context. The components under review were: external context; stewardship and organisational arrangements; financing, resource generation and allocation; healthcare provision; and information systems. Qualitative and quantitative data were collected in the second half of 2008 based on a review of published data and interviews with key informants, exploring past and current patterns of health programme and pandemic response. Results The study shows that health systems in the six countries varied in regard to the epidemiological context, health care financing, and health service provision patterns. For pandemic preparation, all six countries have developed national governance on pandemic preparedness as well as national pandemic influenza preparedness plans and Avian and Human Influenza (AHI response plans. However, the governance arrangements and the nature of the plans differed. In the five developing countries, the focus was on surveillance and rapid containment of poultry related transmission

  6. Synaesthesia in phantom limbs induced with mirrors.

    Science.gov (United States)

    Ramachandran, V S; Rogers-Ramachandran, D

    1996-04-22

    Although there is a vast clinical literature on phantom limbs, there have been no experimental studies on the effects of visual input on phantom sensations. We introduce an inexpensive new device--a 'virtual reality box'--to resurrect the phantom visually to study inter-sensory effects. A mirror is placed vertically on the table so that the mirror reflection of the patient's intact had is 'superimposed' on the felt position of the phantom. We used this procedure on ten patients and found the following results. 1. In six patients, when the normal hand was moved, so that the phantom was perceived to move in the mirror, it was also felt to move; i.e. kinesthetic sensations emerged in the phantom. In D.S. this effect occurred even though he had never experienced any movements in the phantom for ten years before we tested him. He found the return of sensations very enjoyable. 2. Repeated practice led to a permanent 'disappearance' of the phantom arm in patient D.S. and the hand became telescoped into the stump near the shoulder. 3. Using an optical trick, impossible postures--e.g. extreme hyperextension of the fingers--could be induced visually in the phantom. In one case this was felt as a transient 'painful tug' in the phantom. 4. Five patients experienced involuntary painful 'clenching spasms' in the phantom hand and in four of them the spasms were relieved when the mirror was used to facilitate 'opening' of the phantom hand; opening was not possible without the mirror. 5. In three patients, touching the normal hand evoked precisely localized touch sensations in the phantom. Interestingly, the referral was especially pronounced when the patients actually 'saw' their phantom being touched in the mirror. Indeed, in a fourth patient (R.L.) the referral occurred only if he saw his phantom being touched: a curious form of synaesthesia. These experiments lend themselves readily to imaging studies using PET and fMRI. Taken collectively, they suggest that there is a

  7. The effect of MR surface coils on PET quantification in whole-body PET/MR: results from a pseudo-PET/MR phantom study.

    Science.gov (United States)

    Tellmann, L; Quick, H H; Bockisch, A; Herzog, H; Beyer, T

    2011-05-01

    The use of magnetic resonance (MR) radiofrequency (RF) surface coils is a prerequisite for high-quality positron emission tomography (PET)/MR imaging. In lack of in-gantry transmission (TX) sources, the exact position of the RF coils is unknown in PET/MR, and may, therefore, lead to false attenuation correction (AC) of the emission (EM) data. The authors assess lesion and background quantification in AC-PET by mimicking different PET/MR imaging situations using a whole-body (WB) PET-only tomograph. Phantom experiments were performed on a PET tomograph with 68 Ge-rod TX sources. First, a 15-cm plastic cylinder was filled uniformly with [18F]-FDG to simulate a head study. Second, a NEMA NU-2001 image quality phantom (35 x 25 x 25 cm3) was filled uniformly with [18F]-FDG to simulate torso imaging. The phantom contained six lesions (10-38 mm diameter, lesion-to-background ratio 6:1) centred around a 5 cm diameter lung insert. EM and TX measurements were acquired with and without MR head (cylinder) and surface (NU-2001 phantom) RF coils in place. The following imaging situations were mimicked in both head and torso phantom studies: (1) PET scan without MR coils in EM and TX for reference, (2) PET scan with coils in both EM and TX, and (3) PET scan with coils in EM but without coils in TX. Two more set-ups were performed for the torso phantom: (4) PET scan with coils in EM only and phantom shifted slightly compared to (3), and (5) PET scan with coils in EM and TX following local displacement of the surface coils. PET EM data (1)-(4) were corrected for attenuation and scatter using cold TX data. Imaging situations (1)-(3) were repeated with the cylinder phantom and head coil in a combined PET/MR prototype system employing template-based AC. Head phantom: In case the MR head coils were not accounted for during AC (3), central and peripheral background activity concentration was underestimated by 13%-19% when compared to the reference setup (1). The effects of MR coil

  8. Algorithm Variability in the Estimation of Lung Nodule Volume From Phantom CT Scans: Results of the QIBA 3A Public Challenge.

    Science.gov (United States)

    Athelogou, Maria; Kim, Hyun J; Dima, Alden; Obuchowski, Nancy; Peskin, Adele; Gavrielides, Marios A; Petrick, Nicholas; Saiprasad, Ganesh; Colditz Colditz, Dirk; Beaumont, Hubert; Oubel, Estanislao; Tan, Yongqiang; Zhao, Binsheng; Kuhnigk, Jan-Martin; Moltz, Jan Hendrik; Orieux, Guillaume; Gillies, Robert J; Gu, Yuhua; Mantri, Ninad; Goldmacher, Gregory; Zhang, Luduan; Vega, Emilio; Bloom, Michael; Jarecha, Rudresh; Soza, Grzegorz; Tietjen, Christian; Takeguchi, Tomoyuki; Yamagata, Hitoshi; Peterson, Sam; Masoud, Osama; Buckler, Andrew J

    2016-08-01

    Quantifying changes in lung tumor volume is important for diagnosis, therapy planning, and evaluation of response to therapy. The aim of this study was to assess the performance of multiple algorithms on a reference data set. The study was organized by the Quantitative Imaging Biomarker Alliance (QIBA). The study was organized as a public challenge. Computed tomography scans of synthetic lung tumors in an anthropomorphic phantom were acquired by the Food and Drug Administration. Tumors varied in size, shape, and radiodensity. Participants applied their own semi-automated volume estimation algorithms that either did not allow or allowed post-segmentation correction (type 1 or 2, respectively). Statistical analysis of accuracy (percent bias) and precision (repeatability and reproducibility) was conducted across algorithms, as well as across nodule characteristics, slice thickness, and algorithm type. Eighty-four percent of volume measurements of QIBA-compliant tumors were within 15% of the true volume, ranging from 66% to 93% across algorithms, compared to 61% of volume measurements for all tumors (ranging from 37% to 84%). Algorithm type did not affect bias substantially; however, it was an important factor in measurement precision. Algorithm precision was notably better as tumor size increased, worse for irregularly shaped tumors, and on the average better for type 1 algorithms. Over all nodules meeting the QIBA Profile, precision, as measured by the repeatability coefficient, was 9.0% compared to 18.4% overall. The results achieved in this study, using a heterogeneous set of measurement algorithms, support QIBA quantitative performance claims in terms of volume measurement repeatability for nodules meeting the QIBA Profile criteria. Copyright © 2016 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  9. WE-AB-BRA-08: Results of a Multi-Institutional Study for the Evaluation of Deformable Image Registration Algorithms for Structure Delineation Via Computational Phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Loi, G; Fusella, M [University Hospital “Maggiore della Carita”, Novara (Italy); Fiandra, C [University of Torino, Turin (Italy); Lanzi, E [G. Mazzini Hospital, Teramo (Italy); Rosica, A [Regina Elena National Cancer Institute, Rome (Italy); Strigari, L [Centro Oncologico Fiorentino, Florence (Italy); Orlandini, L [A.O. Ordine Mauriziano di Torino, Turin (Italy); Gino, E [Istituto Oncologico Veneto IOV, Padova (Italy); Roggio, A [Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola (Italy); Marcocci, F [ARNAS Civico - Di Cristina - Benfratelli, Palermo (Italy); Iacovello, G; Miceli, R [Tor Vergata University General Hospital, Rome (Italy)

    2015-06-15

    Purpose: To investigate the accuracy of various algorithms for deformable image registration (DIR), to propagate regions of interest (ROIs) in computational phantoms based on patient images using different commercial systems. This work is part of an Italian multi-institutional study to test on common datasets the accuracy, reproducibility and safety of DIR applications in Adaptive Radiotherapy. Methods: Eleven institutions with three available commercial solutions provided data to assess the agreement of DIR-propagated ROIs with automatically drown ROIs considered as ground-truth for the comparison. The DIR algorithms were tested on real patient data from three different anatomical districts: head and neck, thorax and pelvis. For every dataset two specific Deformation Vector Fields (DVFs) provided by ImSimQA software were applied to the reference data set. Three different commercial software were used in this study: RayStation, Velocity and Mirada. The DIR-mapped ROIs were then compared with the reference ROIs using the Jaccard Conformity Index (JCI). Results: More than 600 DIR-mapped ROIs were analyzed. Putting together all JCI data of all institutions for the first DVF, the mean JCI was 0.87 ± 0.7 (1 SD) while for the second DVF JCI was 0.8 ± 0.13 (1 SD). Several considerations on different structures are available from collected data: the standard deviation among different institutions on specific structure raise as the larger is the applied DVF. The higher value is 10% for bladder. Conclusion: Although the complexity of deformation of human body is very difficult to model, this work illustrates some clinical scenarios with well-known DVFs provided by specific software. CI parameter gives the inter-user variability and may put in evidence the need of improving the working protocol in order to reduce the inter-institution JCI variability.

  10. 21. Phantom pain.

    NARCIS (Netherlands)

    Wolff, A.P.; Vanduynhoven, E.; Kleef, M. van; Huygen, F.; Pope, J.E.; Mekhail, N.

    2011-01-01

    Phantom pain is pain caused by elimination or interruption of sensory nerve impulses by destroying or injuring the sensory nerve fibers after amputation or deafferentation. The reported incidence of phantom limb pain after trauma, injury or peripheral vascular diseases is 60% to 80%. Over half the

  11. A computational model unifies apparently contradictory findings concerning phantom pain

    Science.gov (United States)

    Boström, Kim J.; de Lussanet, Marc H. E.; Weiss, Thomas; Puta, Christian; Wagner, Heiko

    2014-06-01

    Amputation often leads to painful phantom sensations, whose pathogenesis is still unclear. Supported by experimental findings, an explanatory model has been proposed that identifies maladaptive reorganization of the primary somatosensory cortex (S1) as a cause of phantom pain. However, it was recently found that BOLD activity during voluntary movements of the phantom positively correlates with phantom pain rating, giving rise to a model of persistent representation. In the present study, we develop a physiologically realistic, computational model to resolve the conflicting findings. Simulations yielded that both the amount of reorganization and the level of cortical activity during phantom movements were enhanced in a scenario with strong phantom pain as compared to a scenario with weak phantom pain. These results suggest that phantom pain, maladaptive reorganization, and persistent representation may all be caused by the same underlying mechanism, which is driven by an abnormally enhanced spontaneous activity of deafferented nociceptive channels.

  12. Comparison of Unmonochromatized Synchrotron Radiation and Conventional X-rays in the Imaging of Mammographic Phantom and Human Breast Specimens: A Preliminary Result

    OpenAIRE

    Jung, Haijo; Kim, Hee-Joung; Kim, Eun-Kyung; Hong, Jin-O; Je, Jung Ho; Hwu, Yeukuang; Tsai, Wen-Li; Magaritondo, Giorgio; Yoo, Hyung-Sik

    2005-01-01

    A simple imaging setup based on the principle of coherence-based contrast X-ray imaging with unmonochromatized synchrotron radiation was used for studying mammographic phantom and human breast specimens. The use of unmonochromatized synchrotron radiation simplifies the instrumentation, decreases the cost and makes the procedure simpler and potentially more suitable for clinical applications. The imaging systems consisted of changeable silicon wafer attenuators, a tungsten slit system, a CdWO4...

  13. Anatomically correct deformable colon phantom

    Science.gov (United States)

    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.

  14. An attempted substitute study of total skin electron therapy technique by using helical photon tomotherapy with helical irradiation of the total skin treatment: a phantom result.

    Science.gov (United States)

    Lin, Chi-Ta; Shiau, An-Cheng; Tien, Hui-Ju; Yeh, Hsin-Pei; Shueng, Pei-Wei; Hsieh, Chen-Hsi

    2013-01-01

    An anthropomorphic phantom was used to investigate a treatment technique and analyze the dose distributions for helical irradiation of the total skin (HITS) by helical tomotherapy (HT). Hypothetical bolus of thicknesses of 0, 10, and 15 mm was added around the phantom body to account for the dose homogeneity and setup uncertainty. A central core structure was assigned as a "complete block" to force the dose tangential delivery. HITS technique with prescribed dose (D p ) of 36 Gy in 36 fractions was generated. The radiochromic EBT2 films were used for the dose measurements. The target region with 95.0% of the D p received by more than 95% of the PTV was obtained. The calculated mean doses for the organs at risk (OARs) were 4.69, 3.10, 3.20, and 2.94 Gy for the lung, heart, liver, and kidneys, respectively. The measurement doses on a phantom surface for a plan with 10 mm hypothetical bolus and bolus thicknesses of 0, 1, 2, and 3 mm are 89.5%, 111.4%, 116.9%, and 117.7% of D p , respectively. HITS can provide an accurate and uniform treatment dose in the skin with limited doses to OARs and is safe to replace a total skin electron beam regimen.

  15. An Attempted Substitute Study of Total Skin Electron Therapy Technique by Using Helical Photon Tomotherapy with Helical Irradiation of the Total Skin Treatment: A Phantom Result

    Directory of Open Access Journals (Sweden)

    Chi-Ta Lin

    2013-01-01

    Full Text Available An anthropomorphic phantom was used to investigate a treatment technique and analyze the dose distributions for helical irradiation of the total skin (HITS by helical tomotherapy (HT. Hypothetical bolus of thicknesses of 0, 10, and 15 mm was added around the phantom body to account for the dose homogeneity and setup uncertainty. A central core structure was assigned as a “complete block” to force the dose tangential delivery. HITS technique with prescribed dose (Dp of 36 Gy in 36 fractions was generated. The radiochromic EBT2 films were used for the dose measurements. The target region with 95.0% of the Dp received by more than 95% of the PTV was obtained. The calculated mean doses for the organs at risk (OARs were 4.69, 3.10, 3.20, and 2.94 Gy for the lung, heart, liver, and kidneys, respectively. The measurement doses on a phantom surface for a plan with 10 mm hypothetical bolus and bolus thicknesses of 0, 1, 2, and 3 mm are 89.5%, 111.4%, 116.9%, and 117.7% of Dp, respectively. HITS can provide an accurate and uniform treatment dose in the skin with limited doses to OARs and is safe to replace a total skin electron beam regimen.

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

    Science.gov (United States)

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

    2013-10-07

    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 (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 for highly penetrating radiations such as

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

    Science.gov (United States)

    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

  18. Forced response of the East Asian summer rainfall over the past millennium: results from a coupled model simulation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jian; Wang, Hongli; Ti, Ruyuan [Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, State Key Laboratory of Lake Science and Environment, Nanjing (China); Wang, Bin [University of Hawaii at Manoa, Department of Meteorology and IPRC, Honolulu, HI (United States); Kuang, Xueyuan [Nanjing University, School of Atmospheric Sciences, Nanjing (China)

    2011-01-15

    The centennial-millennial variation of the East Asian summer monsoon (EASM) precipitation over the past 1000 years was investigated through the analysis of a millennium simulation of the coupled ECHO-G model. The model results indicate that the centennial-millennial variation of the EASM is essentially a forced response to the external radiative forcing (insolation, volcanic aerosol, and green house gases). The strength of the response depends on latitude; and the spatial structure of the centennial-millennial variation differs from the interannual variability that arises primarily from the internal feedback processes within the climate system. On millennial time scale, the extratropical and subtropical precipitation was generally strong during Medieval Warm Period (MWP) and weak during Little Ice Age (LIA). The tropical rainfall is insensitive to the effective solar radiation forcing (insolation plus radiative effect of volcanic aerosols) but significantly responds to the modern anthropogenic radiative forcing. On centennial time scale, the variation of the extratropical and subtropical rainfall also tends to follow the effective solar radiation forcing closely. The forced response features in-phase rainfall variability between the extratropics and subtropics, which is in contrast to the anti-correlation on the interannual time scale. Further, the behavior of the interannual-decadal variation in the extratropics is effectively modulated by change of the mean states on the millennial time scale, suggesting that the structure of the internal mode may vary with significant changes in the external forcing. These findings imply that on the millennial time scale, (a) the proxy data in the extratropical EA may more sensitively reflect the EASM rainfall variations, and (b) the Meiyu and the northern China rainfall provide a consistent measure for the EASM strength. (orig.)

  19. Motor control over the phantom limb in above-elbow amputees and its relationship with phantom limb pain.

    Science.gov (United States)

    Gagné, M; Reilly, K T; Hétu, S; Mercier, C

    2009-08-04

    Recent evidence shows that the primary motor cortex continues to send motor commands when amputees execute phantom movements. These commands are retargeted toward the remaining stump muscles as a result of motor system reorganization. As amputation-induced reorganization in the primary motor cortex has been associated with phantom limb pain we hypothesized that the motor control of the phantom limb would differ between amputees with and without phantom limb pain. Eight above-elbow amputees with or without pain were included in the study. They were asked to produce cyclic movements with their phantom limb (hand, wrist, and elbow movements) while simultaneously reproducing the same movement with the intact limb. The time needed to complete a movement cycle and its amplitude were derived from the kinematics of the intact limb. Electromyographic (EMG) activity from different stump muscles and from the homologous muscles on the intact side was recorded. Different EMG patterns were recorded in the stump muscles depending on the movement produced, showing that different phantom movements are associated with distinct motor commands. Phantom limb pain was associated with some aspects of phantom limb motor control. The time needed to complete a full cycle of a phantom movement was systematically shorter in subjects without phantom limb pain. Also, the amount of EMG modulation recorded in a stump muscle during a phantom hand movement was positively correlated with the intensity of phantom limb pain. Since phantom hand movement-related EMG patterns in above-elbow stump muscles can be considered as a marker of motor system reorganization, this result indirectly supports the hypothesis that amputation-induced plasticity is associated with phantom limb pain severity. The discordance between the (amputated) hand motor command and the feedback from above-elbow muscles might partially explain why subjects exhibiting large EMG modulation during phantom hand movement have more phantom

  20. Contrast-enhanced near-infrared laser mammography with a prototype breast scanner: feasibility study with tissue phantoms and preliminary results of imaging experimental tumors.

    Science.gov (United States)

    Boehm, T; Hochmuth, A; Malich, A; Reichenbach, J R; Fleck, M; Kaiser, W A

    2001-10-01

    Near-infrared (NIR) optical mammography without contrast has a low specificity. The application of optical contrast medium may improve the performance. The concentration-dependent detectability of a new NIR contrast medium was determined with a prototype optical breast scanner. In vivo imaging of experimental tumors was performed. The NIR contrast agent NIR96010 is a newly synthesized, hydrophilic contrast agent for NIR mammography. A concentration-dependent contrast resolution was determined for tissue phantoms consisting of whole milk powder and gelatin. A central part of the phantoms measuring 2 x 2 cm2 without contrast was replaced with phantom material containing 1 micromol/L to 25 nmol/L NIR96010. The composite phantoms were measured with a prototype NIR breast scanner with lasers of lambda1 = 785 nm and lambda2 = 850 nm wavelength. Intensity profiles and standard deviations of the transmission signal in areas with and without contrast were determined by linear fit procedures. Signal-to-noise ratios and spatial resolution as a function of contrast concentration were determined. Near-infrared imaging of five tumor-bearing SCID mice (MX1 breast adenocarcinoma, tumor diameter 5-10 mm) was performed before and after intravenous application of 2 micromol/kg NIR96010. Spectrometry showed an absorption maximum of the contrast agent at 755 nm. No spectral shifts occurred in protein-containing solution. Signal-to-noise ratio in the transmission intensity profiles ranged from 1.1 at 25 nmol/L contrast to 28 at 1 micromol/L. At concentrations <40 nmol/L, no differentiation from the background was possible. The transitional area between the contrast-free edge of the phantom and the central contrast-containing part appeared in the profiles as a steep increase with a width of 4.2 +/- 1.8 mm. The experimental tumors were detectable in nonenhanced images as well as contrast-enhanced images, with better delineation after contrast administration. In postcontrast absorption

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

    Energy Technology Data Exchange (ETDEWEB)

    Kiarashi, Nooshin [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710 and Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708 (United States); Nolte, Adam C. [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710 and Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708 (United States); Sturgeon, Gregory M.; Ghate, Sujata V. [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Segars, William P. [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710 and Medical Physics Graduate Program, Duke University, Durham, North Carolina 27708 (United States); Nolte, Loren W. [Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708 and Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708 (United States); Samei, Ehsan [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708 (United States); Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27708 (United States); Department of Physics, Duke University, Durham, North Carolina 27708 (United States); 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

  2. Revealing the invisible: the paradox of picturing a phantom limb.

    Science.gov (United States)

    Schott, G D

    2014-03-01

    Illustrations of phantom limbs are intriguing as they depict an invisible perception. But such illustrations are also important: they provide a form of objectivity to phenomena, which particularly in the past, have often stretched credulity. Acknowledging the paradox of using images to reveal an absent though sensate body part, depictions of phantom limbs are discussed from the neurological perspective, starting with medieval pictures that showed the miraculous restoration of limbs, and which possibly represented pictorial metaphors for a phantom limb. Centuries later, phantom limbs-whether resulting from amputation or deafferentation-became illustrated, and some reasons for their illustration are considered. Although often depicted by others, the most precise and perhaps revealing illustrations of these phantoms have been those made when patients guide the artist, or draw the phantom themselves. In the case of phantom pains, the painful component too is sometimes illustrated, again, as with the miraculous, in metaphorical terms. More recently, depictions of phantoms have also been revealing in studies of some underlying mechanisms of phantom phenomena, notably in demonstrating novel patterns of referred sensations after amputation and attributable to cortical plasticity. Mention is made of photographs of phantom hands visualized using a mirror box, such visualization recalling full circle the miraculous restoration of limbs pictured in the past. The nature of the outline of the phantom is included in a discussion of demarcation of an invisible body part, before concluding that images of phantom limbs provide an invaluable background to understanding and studying these remarkable sensory phenomena.

  3. Usefulness of milnacipran in treating phantom limb pain

    Science.gov (United States)

    Nagoshi, Yasuhide; Watanabe, Akira; Inoue, Saiko; Kuroda, Tomoki; Nakamura, Mitsuo; Matsumoto, Yoshitake; Fukui, Kenji

    2012-01-01

    Background Amputation of an extremity often results in the sensation of a “phantom limb” where the patient feels that the limb that has been amputated is still present. This is frequently accompanied by “phantom limb pain”. We report here the use of milnacipran, a serotonin and norepinephrine reuptake inhibitor, to treat phantom limb pain after amputation of injured or diseased limbs in three patients. Methods and results The severity of phantom pain before and during treatment was quantified using a visual analog scale. In one case, phantom limb pain responded partially to treatment with high doses of paroxetine, and then replacement with milnacipran further improved the pain relief and long-term full pain relief was achieved. In the two other cases, milnacipran was used as first-line treatment and phantom limb pain responded rapidly. Conclusion These results suggest that milnacipran administration may be useful in phantom limb pain, possibly as a first-line treatment. PMID:23185119

  4. Phantom Remodeling Effect of Dorsal Root Entry Zone Lesioning in Phantom Limb Pain Caused by Brachial Plexus Avulsion.

    Science.gov (United States)

    Son, Byung-Chul; Ha, Sang-Woo

    2015-01-01

    Dorsal root entry zone (DREZ) lesioning has been reported to be effective for phantom limb pain caused by brachial plexus avulsion pain. Most reports on DREZ lesioning for brachial plexus avulsion pain have focused on the results of pain relief without a detailed description of phantom sensations following DREZ lesioning. Two patients (1 with amputation and the other nonamputated) with chronic intractable phantom limb pain caused by brachial plexus avulsion underwent DREZ lesioning on the avulsed segments of the cervical spinal cords. Changes of the phantom limb were observed. Immediately following DREZ lesioning, the phantom limb pain disappeared in the amputee, the phantom arm was shortened and the phantom hand disappeared. The other patient with the nonamputated arm reported an immediate 50% reduction in the size of the phantom hand, and pain relief was up to 70% of the preoperative phantom limb pain. There was no further change in the phantom arm and hand during the follow-up of 1.5-2 years. The phantom arms and hands showed a prompt shortening and reduction in size, rather than a disappearance, following successful DREZ lesioning in patients with chronic phantom limb pain caused by brachial plexus avulsion. © 2015 S. Karger AG, Basel.

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

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Choonsik [Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, FL 32611-8300 (United States)]. E-mail: choonsiklee@gmail.com; Lee, Choonik [Anderson Cancer Center Orlando, Orlando, FL 32806 (United States); Lee, Jai-Ki [Department of Nulcear Engineering, Hanyang University, Haengdang, Sungdong 133-791 (Korea, Republic of)

    2007-05-15

    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.

  6. Usefulness of milnacipran in treating phantom limb pain.

    Science.gov (United States)

    Nagoshi, Yasuhide; Watanabe, Akira; Inoue, Saiko; Kuroda, Tomoki; Nakamura, Mitsuo; Matsumoto, Yoshitake; Fukui, Kenji

    2012-01-01

    Amputation of an extremity often results in the sensation of a "phantom limb" where the patient feels that the limb that has been amputated is still present. This is frequently accompanied by "phantom limb pain". We report here the use of milnacipran, a serotonin and norepinephrine reuptake inhibitor, to treat phantom limb pain after amputation of injured or diseased limbs in three patients. The severity of phantom pain before and during treatment was quantified using a visual analog scale. In one case, phantom limb pain responded partially to treatment with high doses of paroxetine, and then replacement with milnacipran further improved the pain relief and long-term full pain relief was achieved. In the two other cases, milnacipran was used as first-line treatment and phantom limb pain responded rapidly. These results suggest that milnacipran administration may be useful in phantom limb pain, possibly as a first-line treatment.

  7. Prevalence of phantom limb pain, stump pain, and phantom limb sensation among the amputated cancer patients in India: A prospective, observational study

    Directory of Open Access Journals (Sweden)

    Arif Ahmed

    2017-01-01

    Full Text Available Introduction: The phantom limb pain (PLP and phantom limb sensation (PLS are very common among amputated cancer patients, and they lead to considerable morbidity. In spite of this, there is a lack of epidemiological data of this phenomenon among the Asian population. This study was done to provide the data from Indian population. Methods: The prevalence of PLP, stump pain (SP, and PLS was prospectively analyzed from the amputated cancer patients over a period of 2 years in Dr. B.R.A. Institute Rotary Cancer Hospital, All India Institute of Medical Sciences, New Delhi. The risk factors and the impact of phantom phenomenon on patients were also noted. Results: The prevalence of PLP was 41% at 3 and 12 months and 45.3% at 6 months, whereas that of SP and PLS was 14.4% and 71.2% at 3 months, 18.75% and 37.1% at 6 months, 15.8% and 32.4% at 12 months, respectively. There was higher prevalence of PLP and PLS among the patients with history of preamputation pain, smoking with proximal level of amputation, receiving general anesthesia, receiving intravenous (IV opioid postoperative analgesia, and developing neuroma or infection. Conclusion: The prevalence of PLP and PLS was higher among the cancer amputees as compared to SP, and a few risk factors responsible for their higher prevalence were found in our study. The PLP and PLS lead to considerable morbidity in terms of sleep disturbance and depression.

  8. Toxicology Analysis of Tissue-Mimicking Phantom Made From Gelatin

    Science.gov (United States)

    Dolbashid, A. S.; Hamzah, N.; Zaman, W. S. W. K.; Mokhtar, M. S.

    2017-06-01

    Skin phantom mimics the biological skin tissues as it have the ability to respond to changes in its environment. The development of tissue-mimicking phantom could contributes towards the reduce usage of animal in cosmetics and pharmacokinetics. In this study, the skin phantoms made from gelatin were tested with four different commonly available cosmetic products to determine the toxicity of each substance. The four substances used were; mercury-based whitening face cream, carcinogenic liquid make-up foundation, paraben-based acne cleanser, and organic lip balm. Toxicity test were performed on all of the phantoms. For toxicity testing, topographical and electrophysiological changes of the phantoms were evaluated. The ability of each respective phantom to react with mild toxic substances and its electrical resistance were analysed in to determine the toxicity of all the phantom models. Four-electrode method along with custom made electrical impedance analyser was used to differentiate electrical resistance between intoxicated phantom and non-intoxicated phantom in this study. Electrical resistance values obtained from the phantom models were significantly higher than the control group. The result obtained suggests the phantom as a promising candidate to be used as alternative for toxicology testing in the future.

  9. A study of partial volume effect on SPECT imaging using myocardial phantom. With HCM (ASH) model myocardial phantom

    Energy Technology Data Exchange (ETDEWEB)

    Onoguchi, Masahisa [Kanazawa Univ. (Japan). School of Medicine

    1997-05-01

    In order to evaluate simultaneously both myocardial perfusion and regional wall motion using ECG-gated myocardial SPECT imaging, correction for the partial volume effect (PVE) should be performed. For the quantitative analysis of myocardial SPECT imaging in patients with hypertrophic cardiomyopathy (HCM), we formed a new phantom simulating HCM with various septal wall thicknesses and estimated PVE using the recovery coefficient (RC). The value of RC in all phantoms increased with increasing thickness of the septal wall reaching a plateau at 25 mm for the cylindrical phantom and 25 mm for the Ep-phantom. Compared with the RC value, the PMMA-phantom had little influence on PVE. Therefore, our results suggested that the count in the septal wall could be underestimated if PVE was corrected by the value obtained for the cylindrical phantom. In conclusion, our new phantom simulating HCM was useful in assessing PVE in the hypertrophic septal wall. (author)

  10. The Jurassic to Paleogene detrital record of the Central Asian Orogenic Belt: results from the Kyrgyz Tien Shan

    Science.gov (United States)

    De Pelsmaeker, Elien; Jolivet, Marc; Dransart Laborde, Amandine; Robin, Cécile; Zhimulev, Fedor; Poujol, Marc; Nachtergaele, Simon; Glorie, Stijn; De Clercq, Shana; Batalev, Vladislav; De Grave, Johan

    2017-04-01

    The Central Asian Orogenic Belt (CAOB) represents one of the largest Phanerozoic accretionary orogens in the world, pinched between North China - Tarim, Kazakhstan and the Siberian craton. It stretches from the Pamir in the southwest, over the Tien Shan, Junggar, Altai and Sayan mountain ranges to the Baikal rift in the northeast. The basement of the CAOB exists of various tectonic units that were assembled during several Paleozoic collision-accretion events. By the Permian, the accretionary tectonics in the CAOB culminated as all major composing units were joined. After final construction in the Late Paleozoic, the CAOB was subjected to several phases of Mesozoic deformation and was again reactivated in the Late Cenozoic as distant effect of the India-Eurasia collision. The Meso-Cenozoic reactivation episodes occurred in an intracontinental setting, related to tectonic far-field effects originating at the Eurasian margins. Subsequently intracontinental orogens, such as Tien Shan, were built superimposed on the inherited basement architecture and the erosion products of their exhuming mountain ranges accumulated in sedimentary basins. New sedimentological and detrital zircon U-Pb (LA-ICP-MS) results from several Jurassic to Paleogene sedimentary sections in Kyrgyzstan provide new insights in the Mesozoic - early Cenozoic geodynamic evolution and related basin-range interactions of the Kyrgyz Tien Shan. Studied sedimentary sections are located in the Fergana and Yarkand-Fergana basins to the west of the Talas-Fergana Fault (TFF) and in the Issyk-Kul and Ming-Kush-Kökömeren basins to the east of the TFF. The U-Pb ages of the post-Precambrian zircon grains found in 18 Jurassic to Paleogene sandstones, can be generally divided into four groups: Caledonian (470-390 Ma), Hercynian (315-260 Ma), Triassic (250-210 Ma) and Jurassic (190-160 Ma) ages. The differences in sedimentation pattern and detrital zircon U-Pb age components suggest that the TFF played an important

  11. Asian Ginseng

    Science.gov (United States)

    ... senticosus) is not related to true ginseng. In traditional Chinese medicine, Asian ginseng was used as a ... recommend against its use by infants, children, and women who are pregnant or breastfeeding. The most common ...

  12. Phantom Limb Pain: Mechanisms and Treatment Approaches

    Science.gov (United States)

    Subedi, Bishnu; Grossberg, George T.

    2011-01-01

    The vast amount of research over the past decades has significantly added to our knowledge of phantom limb pain. Multiple factors including site of amputation or presence of preamputation pain have been found to have a positive correlation with the development of phantom limb pain. The paradigms of proposed mechanisms have shifted over the past years from the psychogenic theory to peripheral and central neural changes involving cortical reorganization. More recently, the role of mirror neurons in the brain has been proposed in the generation of phantom pain. A wide variety of treatment approaches have been employed, but mechanism-based specific treatment guidelines are yet to evolve. Phantom limb pain is considered a neuropathic pain, and most treatment recommendations are based on recommendations for neuropathic pain syndromes. Mirror therapy, a relatively recently proposed therapy for phantom limb pain, has mixed results in randomized controlled trials. Most successful treatment outcomes include multidisciplinary measures. This paper attempts to review and summarize recent research relative to the proposed mechanisms of and treatments for phantom limb pain. PMID:22110933

  13. Phantom Limb Pain: Mechanisms and Treatment Approaches

    Directory of Open Access Journals (Sweden)

    Bishnu Subedi

    2011-01-01

    Full Text Available The vast amount of research over the past decades has significantly added to our knowledge of phantom limb pain. Multiple factors including site of amputation or presence of preamputation pain have been found to have a positive correlation with the development of phantom limb pain. The paradigms of proposed mechanisms have shifted over the past years from the psychogenic theory to peripheral and central neural changes involving cortical reorganization. More recently, the role of mirror neurons in the brain has been proposed in the generation of phantom pain. A wide variety of treatment approaches have been employed, but mechanism-based specific treatment guidelines are yet to evolve. Phantom limb pain is considered a neuropathic pain, and most treatment recommendations are based on recommendations for neuropathic pain syndromes. Mirror therapy, a relatively recently proposed therapy for phantom limb pain, has mixed results in randomized controlled trials. Most successful treatment outcomes include multidisciplinary measures. This paper attempts to review and summarize recent research relative to the proposed mechanisms of and treatments for phantom limb pain.

  14. A nonlinear elasticity phantom containing spherical inclusions

    Science.gov (United States)

    Pavan, Theo Z.; Madsen, Ernest L.; Frank, Gary R.; Jiang, Jingfeng; Carneiro, Antonio A. O.; Hall, Timothy J.

    2012-08-01

    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 have 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 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) agree with that predicted with nonlinear FEA.

  15. Silicone breast phantoms for elastographic imaging evaluation.

    Science.gov (United States)

    Kashif, Amer S; Lotz, Thomas F; McGarry, Matthew D; Pattison, Adam J; Chase, James G

    2013-06-01

    Breast cancer is a major public health issue for women, and early detection significantly increases survival rate. Currently, there is increased research interest in elastographic soft-tissue imaging techniques based on the correlation between pathology and mechanical stiffness. Anthropomorphic breast phantoms are critical for ex vivo validation of emerging elastographic technologies. This research develops heterogeneous breast phantoms for use in testing elastographic imaging modalities. Mechanical property estimation of eight different elastomers is performed to determine storage moduli (E') and damping ratios (ζ) using a dynamic mechanical analyzer. Dynamic compression testing was carried out isothermally at room temperature over a range of 4-50 Hz. Silicone compositions with physiologically realistic storage modulus were chosen for mimicking skin adipose, cancerous tumors, and pectoral muscles and 13 anthropomorphic breast phantoms were constructed for ex vivo trials of digital image elastotomography (DIET) breast cancer screening system. A simpler fabrication was used to assess the possibility of multiple tumor detection using magnetic resonance elastography (MRE). Silicone materials with ranges of storage moduli (E') from 2 to 570 kPa and damping ratios (ζ) from 0.03 to 0.56 were identified. The resulting phantoms were tested in two different elastographic breast cancer diagnostic modalities. A significant contrast was successfully identified between healthy tissues and cancerous tumors both in MRE and DIET. The phantoms presented promise aid to researchers in elastographic imaging modalities for breast cancer detection and provide a foundation for silicone based phantom materials for mimicking soft tissues of other human organs.

  16. The South Asian genome.

    Directory of Open Access Journals (Sweden)

    John C Chambers

    Full Text Available The genetic sequence variation of people from the Indian subcontinent who comprise one-quarter of the world's population, is not well described. We carried out whole genome sequencing of 168 South Asians, along with whole-exome sequencing of 147 South Asians to provide deeper characterisation of coding regions. We identify 12,962,155 autosomal sequence variants, including 2,946,861 new SNPs and 312,738 novel indels. This catalogue of SNPs and indels amongst South Asians provides the first comprehensive map of genetic variation in this major human population, and reveals evidence for selective pressures on genes involved in skin biology, metabolism, infection and immunity. Our results will accelerate the search for the genetic variants underlying susceptibility to disorders such as type-2 diabetes and cardiovascular disease which are highly prevalent amongst South Asians.

  17. Zoogeographical results of the bicentennial study of the northern part of the asian population of Phoenicopterus roseus

    Directory of Open Access Journals (Sweden)

    Boris Yu. Kassal

    2017-02-01

    Full Text Available Over a period of 205 years, there have been carried out dozens of censuses of nests and nesting bird individuals, summerings and non-nesting bird individuals, winterings and wintering bird individuals, the determinations of migration routes in the Caspian region and across the Caspian Sea, in Central and Southern Kazakhstan, Turkmenistan, Azerbaijan and Russia. Until the early XXI century, the main flamingo nesting sites were located in the Caspian region and along the Caspian Sea within the Russian Empire / USSR / Commonwealth of Independent States. It was found that such a geographical distribution of flamingo nesting sites was established until 1930 by the relative stability of the global climate conditions in northern Eurasia that have caused the stand of water level in the Caspian Sea. During this period, in the northern part of the Asian population the monitoring of the flamingo had the form of collecting mainly qualitative information. Amongst these are the determination of the locations of breeding sites, summerings and winterings; the bird's abundance was characterised mainly using the epithets. The next period (from 1931 to 1977 was caused by the development of anthropogenic influences and by changes of global climatic conditions in northern Eurasia, which have caused a decrease in the water level in the Caspian Sea. Environmental effects of the hydrological regime changes were the most significant in the shallow north-eastern part of the Caspian Sea. The breeding sites and the summerings (that were located there had changed dislocation. Sometimes such a dislocation was observed over a wide area, up to the complete loss of breeding sites and summerings. During this period, the observations had the character of quantative information collecting and clarification of qualitative data: determination of new locations of breeding sites, duration of their existence, location of summerings and winterings, sizes of flocks and groupings, and

  18. Depression and bone mineral density: is there a relationship in elderly Asian men? Results from Mr. Os (Hong Kong).

    Science.gov (United States)

    Wong, Samuel Y S; Lau, Edith M C; Lynn, Henry; Leung, P C; Woo, Jean; Cummings, Steve R; Orwoll, Eric

    2005-06-01

    Previous epidemiological study has suggested that depression might be associated with low bone mass in Caucasian women. This has not been studied in Asian men. Mr. Os (Hong Kong) is the first, large, cohort study on osteoporosis in Asian men, and the current analysis deals with the association between depression and bone mass in this group. Data from the baseline examination of Mr. Os (Hong Kong) were used. Two thousand Hong Kong men aged 65 to 92 years were recruited from the community. Depression was diagnosed by face-to-face interview, using a validated Chinese version of the Geriatric Depression Scale (GDS), with depression being defined as a cut-off score of 8 or more. Bone mineral density (BMD) of the lumbar spine, total hip and total body was measured by dual X-ray densitometry (DEXA) using the Hologic QDR-4500 W densitometer. Multiple regression was used to compare BMD in depressed and non-depressed subjects, controlling for confounding variables. In the study sample 8.5% of men were found to be depressed, and the BMD at the total hip in these subjects was 2.1% lower than in non-depressed subjects (95% CI -0.13 to -4.1), after adjustment for age, body weight, medical history, alcohol consumption, cigarette smoking, calcium intake, physical activity and antidepressant use. Depression was associated with a 1.4-fold (95% CI 1.00 to 2.08) relative risk (RR) of being diagnosed with a T-score equal to or less than -1.0 (low bone mass). We conclude that depression is associated with lower BMD; however, to determine whether depression causes lower BMD or vice versa, we will need to await findings from future prospective studies.

  19. Jamitons: Phantom Traffic Jams

    Science.gov (United States)

    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…

  20. The Phantom Menace

    DEFF Research Database (Denmark)

    Vium, Christian

    2013-01-01

    as a phantom menace, which asserts itself through a form of omnipresent fear, nurtured by an inherent opaqueness. As this fundamental fear progressively permeates the nomadic landscape, it engenders a recasting of mobile strategies among the nomadic pastoralist groups who inhabit the interstitial desert spaces....

  1. Brachial plexus block in phantom limb pain: a case report.

    Science.gov (United States)

    Preissler, Sandra; Dietrich, Caroline; Meissner, Winfried; Huonker, Ralph; Hofmann, Gunther O; Miltner, Wolfgang H R; Weiss, Thomas

    2011-11-01

    The purpose of this case report is twofold: first, to present evidence of long-lasting relief in a patient suffering from phantom limb pain after pharmacologically blocking his plexus brachialis and, second, to replicate results from a previous study focusing on cortical reorganization and phantom limb pain. Before regional anesthesia, the patient suffered from a phantom hand that cramped and was immovable. We performed a diagnostic axillary blockade of the brachial plexus to differentiate peripheral from more central contributions to phantom limb pain. During blockade of the brachial plexus, the patient reported a reduction of phantom limb pain for the first time following years of suffering and a complete loss of cramping together with muscle relaxation of the phantom hand. Additionally, we found cortical reorganization in the primary somatosensory cortex (re-reorganization). Strikingly, the relaxed phantom limb together with the reduction of phantom limb pain remained preserved even 6 months after blockade of the brachial plexus. A single temporary blockade of the brachial plexus may relieve phantom limb pain and unpleasant phantom feelings (cramping) for an extended period. Wiley Periodicals, Inc.

  2. Phantom pain after eye amputation

    DEFF Research Database (Denmark)

    Rasmussen, Marie L R; Prause, Jan U; Toft, Peter B

    2011-01-01

    Purpose: To characterize the quality of phantom pain, its intensity and frequency following eye amputation. Possible triggers and relievers of phantom pain are investigated. Methods: The hospital database was searched using surgery codes for patients who received ocular evisceration, enucleation,...... appears to be similar to the phantom pain suffered by limb amputees. Patients should be informed about this potential complication before surgery....

  3. Structured movement representations of a phantom limb associated with phantom limb pain.

    Science.gov (United States)

    Osumi, Michihiro; Sumitani, Masahiko; Wake, Naoki; Sano, Yuko; Ichinose, Akimichi; Kumagaya, Shin-Ichiro; Kuniyoshi, Yasuo; Morioka, Shu

    2015-09-25

    The relation between phantom limb pain (PLP) and the movement representation of a phantom limb remains controversial in several areas of neurorehabilitation, although there are a few studies in which the representation of phantom limb movement was precisely evaluated. We evaluated the structured movement representation of a phantom limb objectively using a bimanual circle-line coordination task. We then investigated the relation between PLP and the structured movement representation. Nine patients with a brachial plexus avulsion injury were enrolled who perceived a phantom limb and had neuropathic pain. While blindfolded, the participants repeatedly drew vertical lines using the intact hand and intended to draw circles using the phantom limb simultaneously. "Drawing of circles" by the phantom limb resulted in an oval transfiguration of the vertical lines ("bimanual coupling" effect). We used an arbitrary ovalization index (OI) to quantify the oval transfiguration. When the OI neared 100%, the trajectory changed toward becoming more circular. A significant negative correlation was observed between the intensity of PLP and the OI (r=-0.66, pphantom limb are necessary for alleviating PLP. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  4. A realistic pelvic phantom for electrical impedance measurement.

    Science.gov (United States)

    Dunne, Eoghan; McGinley, Brian; O'Halloran, Martin; Porter, Emily

    2017-12-22

    To design and fabricate an anatomically and conductively accurate phantom for electrical impedance studies of non-invasive bladder volume monitoring. Approach: A modular pelvic phantom was designed and fabricated, consisting of a mechanically and conductively stable boundary wall, a background medium, and bladder phantoms. The wall and bladders are made of conductive polyurethane. The background material is an ultrasound gel-based mixture, with conductivity matched to a weighted average of the pelvic cavity organs, bone, muscle and fat. The phantom boundary is developed using a computer tomography model of a male human pelvis. The bladder phantoms were designed to correlate with human bladder dimensions. Electrical impedance measurements of the phantom were recorded, and images produced using six different bladder phantoms and a realistic finite element model. Main results: Five different bladder volumes were successfully imaged using an empty bladder as a reference. The average conductivity index from the reconstructed images showed a strong positive correlation with the bladder phantom volumes. Significance: A conductively and anatomically accurate pelvic phantom was developed for non-invasive bladder volume monitoring using electrical impedance measurements. Several bladders were designed to correlate with actual human bladder volumes, allowing for accurate volume estimation. The conductivity of the phantom is accurate over 50-250 kHz. This phantom can allow: changeable electrode location, contact and size; multi-layer electrodes configurations; increased complexity by addition of other organ or bone phantoms; and electrode movement and deformation. Overall, the pelvic phantom enables greater scope for experimentation and system refinement as a precursor to in-man clinical studies. © 2017 Institute of Physics and Engineering in Medicine.

  5. 18F-FDG PET-CT for detecting recurrent gastric adenocarcinoma: results from a Non-Oriental Asian population.

    Science.gov (United States)

    Sharma, Punit; Singh, Harmandeep; Suman, Sudhir K C; Sharma, Atul; Reddy, Rama Mohan; Thulkar, Sanjay; Bal, Chandrasekhar; Malhotra, Arun; Kumar, Rakesh

    2012-09-01

    To evaluate the utility of fluorine-18 fluorodeoxyglucose (18F-FDG) PET-CT in the diagnosis of recurrent gastric adenocarcinoma in a Non-Oriental Asian population. In this retrospective analysis, data from 72 Non-Oriental Asian patients, who underwent 93 18F-FDG PET-CT studies, were evaluated. All patients had histopathologically proven gastric adenocarcinoma, for which they had undergone primary treatment. PET-CT was performed for suspected recurrence or for post-therapy surveillance. PET-CT findings were analysed on a per-patient and per-region basis (local/lymph node/liver/lung/bone/others). A combination of clinical follow-up (minimum 6 months; range: 6-36 months), imaging follow-up and/or histopathology (when available) was taken as the reference standard. Sensitivity, specificity and predictive values were calculated for PET-CT on both a per-study and per-lesion basis. The mean patient age was 52.8 ± 11.8 years (male/female: 52/20). Out of 93 PET-CT studies, 56 (60.2%) were positive and 37 (39.8%) were negative for recurrent disease. On per-study-based analysis, 18F-FDG PET-CT has a sensitivity, specificity and accuracy of 95.9, 79.5 and 88.1%, respectively. The accuracy of 18F-FDG PET-CT was 89.2% for local recurrence, 94.6% for lymph nodes, 96.7% for liver, 96.7% for lung, 98.9% for bone and 98.9% for other sites. The accuracy of 18F-FDG PET-CT was lower for local recurrence as compared with that for liver (P=0.012) and bone (P=0.012). No significant difference was found in the diagnostic accuracies for other regions. 18F-FDG PET-CT is highly sensitive and specific for detecting recurrence in patients with gastric adenocarcinoma. It shows high accuracy both on a per-patient and per-lesion basis.

  6. Calibrating pen dosimeters with and without a phantom

    Energy Technology Data Exchange (ETDEWEB)

    Nonato, Fernanda B.C.; Cescon, Claudinei T.; Caldas, Linda V.E., E-mail: fbnonato@ipen.b, E-mail: ctcescon@ipen.b, E-mail: lcaldas@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Thirty one direct reading dosimeters (pen dosimeters) were calibrated and tested in standard beams of gamma radiation, with and without the use of a phantom. The calibration was performed with a Co-60 source and tested with a Cs-137 source. The dose-response curves of the pen dosimeters and their calibration factors for a Co-60 source, with and without the use of a phantom were obtained. The results show the need to calibrate the pen dosimeters with a phantom. (author)

  7. Creating 3D gelatin phantoms for experimental evaluation in biomedicine

    Directory of Open Access Journals (Sweden)

    Stein Nils

    2015-09-01

    Full Text Available We describe and evaluate a setup to create gelatin phantoms by robotic 3D printing. Key aspects are the large workspace, reproducibility and resolution of the created phantoms. Given its soft tissue nature, the gelatin is kept fluid during inside the system and we present parameters for additive printing of homogeneous, solid objects. The results indicate that 3D printing of gelatin can be an alternative for quickly creating larger soft tissue phantoms without the need for casting a mold.

  8. Toward a reference standard for tissue phantoms

    Science.gov (United States)

    Di Ninni, Paola; Martelli, Fabrizio; Zaccanti, Giovanni

    2011-03-01

    A reference standard for tissue-simulating phantoms, i.e., a phantom with well known and stable optical properties, reproducible, and easy to be found, would be very useful for many applications based on measurements of diffused light. Although many tissue-equivalent phantoms have been proposed, to our knowledge none of them has been characterized sufficiently well to be suggested as a reference standard. Based on the results of measurements of optical properties we carried out at visible and NIR wavelengths, the use of Intralipid 20% diluted in water as diffusive medium, and of India ink as absorber, is here suggested as a first step towards a diffusive reference standard for tissue-simulating phantoms. As for Intralipid 20%, measurements carried out on samples from nine different batches with expiry dates spreading over ten years showed surprisingly small batch-to-batch variations. For the reduced scattering coefficient the maximum deviation from the value averaged over the nine batches was of about 2%, and the results for the absorption coefficient were very close to those for pure water. As for India ink measurements on samples from different batches and from five different brands showed large inter-brand and inter-batch variations for both the absorption and the extinction coefficient. On the contrary, small variations have been observed for the ratio between the absorption and the extinction coefficient. Intralipid 20% and Indian ink can be therefore easily mixed to obtain liquid phantoms with well known optical properties. This phantom can be a first step towards a reference standard for optical tissue phantoms.

  9. Phantom limb pain from spinal sarcoma: a case report.

    Science.gov (United States)

    Cruz, Ernesto; Dangaria, Harsh T

    2013-07-01

    Phantom limb pain is a frequent sequela of amputation. A high prevalence of residual limb pain and back pain also exists among amputees. We present a case of a new-onset severe phantom limb pain resulting from a metastatic spinal mass in an 81-year-old patient with a history of malignant sarcoma and an old hip disarticulation amputation. The metastatic lesion, upon imaging, was found to involve the L3 vertebra and caused moderate compression of the thecal sac on the right and severe right lateral recess stenosis. After the mass was resected, the patient's phantom limb pain resolved. Our case report demonstrates that spinal metastatic pathologies may be a cause of phantom limb pain and should be included in the differential diagnosis of new-onset phantom limb pain or a change in phantom limb pain. Copyright © 2013 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

  10. Targeting of Asian Americans and Pacific Islanders by the tobacco industry: results from the Minnesota Tobacco Document Depository.

    Science.gov (United States)

    Muggli, M E; Pollay, R W; Lew, R; Joseph, A M

    2002-09-01

    The study objective was to review internal tobacco industry documents written between 1985 and 1995 regarding the Asian American and Pacific Islander (AAPI) population in the USA. These documents detail opportunities and barriers to promotion of tobacco products, as viewed by the tobacco industry and its market research firms. /methods: Researchers reviewed tobacco industry documents from the document depository in Minneapolis, Minnesota and the tobacco industry's website, The Tobacco Archive, in a systematic fashion. A combined technique was employed using title keywords, dates, and names to search the 4(b) index. A review of internal tobacco company documents reveal that during the late 1980s, the industry and its market research firms recognised the importance of the AAPI community as a potential business market. Documents describe the population growth in this community, the high prevalence of smoking in countries of origin, high purchasing power of AAPI immigrants, cultural predisposition to smoking, opportunities afforded by the high proportion of retail businesses under AAPI ownership, barriers to developing the AAPI market, comprehensive campaigns, and political and lobbying efforts. Comprehensive campaigns were designed to integrate promotion efforts in AAPI consumer, retail, and business communities. The documents show that the tobacco industry developed specific promotion strategies to target the AAPI population. Tobacco control initiatives in the AAPI group have been slower to develop than in other targeted ethnic groups, and may benefit by increased awareness of industry methods to promote tobacco use.

  11. Tissue-like phantoms

    Science.gov (United States)

    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.

  12. Role of Social Support in Examining Acculturative Stress and Psychological Distress Among Asian American Immigrants and Three Sub-groups: Results from NLAAS.

    Science.gov (United States)

    Singh, Shipra; McBride, Kimberly; Kak, Vivek

    2015-12-01

    This study examined the impact of acculturative stress and social support (family and friend) on psychological distress among Asian American immigrants and three Asian sub-groups (Vietnamese, Filipino and Chinese) immigrants. The National Latino and Asian American Study 2002-2003 dataset was used. The study findings were: (1) among all Asian American immigrants high language barrier and discrimination stress were associated with increased level of psychological distress, but similar association was not present for legal stress; (2) among all Asian American immigrants high family social support decreased the levels of psychological distress, and in addition, friend social support buffered the relationship of discrimination and psychological distress; and (3) among Vietnamese, Filipino, and Chinese, differential association of social support and acculturative stress to psychological distress were observed. These findings highlight the importance of social support among Asian American immigrants, while also paying attention to the variation that may exist between different sub-groups.

  13. Atypical supernumerary phantom limb and phantom limb pain in two patients with pontine hemorrhage.

    Science.gov (United States)

    Yoo, Seung Don; Kim, Dong Hwan; Jeong, Yong Seol; Chon, Jinmann; Bark, Jihea

    2011-06-01

    Phantom limbs are usually observed after amputation of extremities. In patients after a stroke, a similar but rarely occurring phenomenon consisting of the patient experiencing the presence of an additional limb has been described. This phenomenon, generally called supernumerary phantom limb (SPL), may be caused by lesions in the right or left cerebral hemisphere, but has been predominantly reported in patients who have had a right hemispheric stroke. We report two cases of atypical SPL and phantom limb pain (PLP) after pontine hemorrhage. The patients were treated conservatively and their symptoms lasted more than 1 month. This is the first report of SPLs after left pontine hemorrhage, and phantom perception and pain lasted longer than those in previously observed cases. Our results indicate that SPL may be more common than reported; therefore, thorough examinations are essential for the care of stroke patients.

  14. Multi-layered tissue head phantoms for noninvasive optical diagnostics

    Directory of Open Access Journals (Sweden)

    M. S. Wróbel

    2015-05-01

    Full Text Available Extensive research in the area of optical sensing for medical diagnostics requires development of tissue phantoms with optical properties similar to those of living human tissues. Development and improvement of in vivo optical measurement systems requires the use of stable tissue phantoms with known characteristics, which are mainly used for calibration of such systems and testing their performance over time. Optical and mechanical properties of phantoms depend on their purpose. Nevertheless, they must accurately simulate specific tissues they are supposed to mimic. Many tissues and organs including head possess a multi-layered structure, with specific optical properties of each layer. However, such a structure is not always addressed in the present-day phantoms. In this paper, we focus on the development of a plain-parallel multi-layered phantom with optical properties (reduced scattering coefficient $\\mu_{s}^{\\prime}$ and absorption coefficient μa corresponding to the human head layers, such as skin, skull, and gray and white matter of the brain tissue. The phantom is intended for use in noninvasive diffuse near-infrared spectroscopy (NIRS of human brain. Optical parameters of the fabricated phantoms are reconstructed using spectrophotometry and inverse adding-doubling calculation method. The results show that polyvinyl chloride-plastisol (PVCP and zinc oxide (ZnO nanoparticles are suitable materials for fabrication of tissue mimicking phantoms with controlled scattering properties. Good matching was found between optical properties of phantoms and the corresponding values found in the literature.

  15. Physical phantom of craniospinal hydrodynamics.

    Science.gov (United States)

    Bouzerar, R; Czosnyka, M; Czosnyka, Z; Balédent, Olivier

    2012-01-01

    Inside the craniospinal system, blood, and cerebrospinal fluid (CSF) interactions occurring through volume exchanges are still not well understood. We built a physical model of this global hydrodynamic system. The main objective was to study, in controlled conditions, CSF-blood interactions to better understand the phenomenon underlying pathogenesis of hydrocephalus. A structure representing the cranium is connected to the spinal channel. The cranium is divided into compartments mimicking anatomical regions such as ventricles or aqueduct cerebri. Resistive and compliant characteristics of blood and CSF compartments can be assessed or measured using pressure and flow sensors incorporated in the model. An arterial blood flow input is generated by a programmable pump. Flows and pressures inside the system are simultaneously recorded. Preliminary results show that the model can mimic venous and CSF flows in response to arterial pressure input. Pulse waveforms and volume flows were measured and confirmed that they partially replicated the data previously obtained with phase-contrast magnetic resonance imaging. The phantom shows that CSF oscillations directly result from arteriovenous flow, and intracranial pressure measurements show that the model obeys an exponential relationship between pressure and intracranial volume expansion. The phantom will be useful to investigate the hydrodynamic hypotheses underlying development of hydrocephalus.

  16. Phantom breast syndrome

    Directory of Open Access Journals (Sweden)

    Ramesh

    2009-01-01

    Full Text Available Phantom breast syndrome is a type of condition in which patients have a sensation of residual breast tissue and can include both non-painful sensations as well as phantom breast pain. The incidence varies in different studies, ranging from approximately 30% to as high as 80% of patients after mastectomy. It seriously affects quality of life through the combined impact of physical disability and emotional distress. The breast cancer incidence rate in India as well as Western countries has risen in recent years while survival rates have improved; this has effectively increased the number of women for whom post-treatment quality of life is important. In this context, chronic pain following treatment for breast cancer surgery is a significantly under-recognized and under-treated problem. Various types of chronic neuropathic pain may arise following breast cancer surgery due to surgical trauma. The cause of these syndromes is damage to various nerves during surgery. There are a number of assumed factors causing or perpetuating persistent neuropathic pain after breast cancer surgery. Most well-established risk factors for developing phantom breast pain and other related neuropathic pain syndromes are severe acute postoperative pain and greater postoperative use of analgesics. Based upon current evidence, the goals of prophylactic strategies could first target optimal peri-operative pain control and minimizing damage to nerves during surgery. There is some evidence that chronic pain and sensory abnormalities do decrease over time. The main group of oral medications studied includes anti-depressants, anticonvulsants, opioids, N-methyl-D-asparate receptor antagonists, mexilitine, topical lidocaine, cannabinoids, topical capsaicin and glysine antagonists. Neuromodulation techniques such as motor cortex stimulation, spinal cord stimulation, and intrathecal drug therapies have been used to treat various neuropathic pain syndromes.

  17. Phantom limb phenomenon as an example of body image distortion

    Directory of Open Access Journals (Sweden)

    Razmus Magdalena

    2017-06-01

    Full Text Available Introduction: The perception of one’s own body, its mental representation, and emotional attitude to it are the components of so-called “body image” [1]. The aim of the research was to analyse phantom pain and non-painful phantom sensations as results of limb loss and to explain them in terms of body image distortion.

  18. The Phantom of Liberty

    DEFF Research Database (Denmark)

    One of the few things we have in common in contemporary society is the future of our children. But it seems that even the “we” of childhood, of learning and free play, has turned into a common ground for instrumentalization and competition. Today, the pedagogical paradox—Kant’s meditation on the ......? These are some of the questions addressed by The Phantom of Liberty, which sets out to reestablish a social and aesthetic dialogue between visual art and psychology, philosophy, pedagogy, and critical journalism....

  19. Usefulness of milnacipran in treating phantom limb pain

    Directory of Open Access Journals (Sweden)

    Matsumoto Y

    2012-11-01

    Full Text Available Yasuhide Nagoshi,1 Akira Watanabe,1 Saiko Inoue,1 Tomoki Kuroda,2 Mitsuo Nakamura,3 Yoshitake Matsumoto,4 Kenji Fukui31Department of Psychiatry (Psychosomatic Medicine, Kyoto First Red Cross Hospital, Kyoto, Japan; 2Gojouyama Hospital, Nara, Japan; 3Department of Psychiatry, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan; 4Matsumoto Clinic, Kyoto, JapanBackground: Amputation of an extremity often results in the sensation of a “phantom limb” where the patient feels that the limb that has been amputated is still present. This is frequently accompanied by “phantom limb pain”. We report here the use of milnacipran, a serotonin and norepinephrine reuptake inhibitor, to treat phantom limb pain after amputation of injured or diseased limbs in three patients.Methods and results: The severity of phantom pain before and during treatment was quantified using a visual analog scale. In one case, phantom limb pain responded partially to treatment with high doses of paroxetine, and then replacement with milnacipran further improved the pain relief and long-term full pain relief was achieved. In the two other cases, milnacipran was used as first-line treatment and phantom limb pain responded rapidly.Conclusion: These results suggest that milnacipran administration may be useful in phantom limb pain, possibly as a first-line treatment.Keywords: milnacipran, paroxetine, phantom limb pain, selective serotonin reuptake inhibitor (SSRI, serotonin and norepinephrine reuptake inhibitor (SNRI

  20. Tissue-Like Phantoms as a Platform for Inserted Fluorescence Nano-Probes

    OpenAIRE

    Nayhoz, Tsviya; Barnoy, Eran A.; Fixler, Dror

    2016-01-01

    Tissue-like phantoms are widely used as a model for mimicking the optical properties of live tissue. This paper presents the results of a diffusion reflection method and fluorescence lifetime imaging microscopy measurements of fluorescein-conjugated gold nanorods in solution, as well as inserted in solid tissue-imitating phantoms. A lack of consistency between the fluorescence lifetime results of the solutions and the phantoms raises a question about the ability of tissue-like phantoms to mai...

  1. The impact of anthropometric patient-phantom matching on organ dose: A hybrid phantom study for fluoroscopy guided interventions

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Perry B.; Geyer, Amy; Borrego, David; Ficarrotta, Kayla; Johnson, Kevin; Bolch, Wesley E. [Nuclear and Radiological Engineering, University of Florida, Gainesville, Florida 32611 (United States); Radiology, University of Florida, Jacksonville, Florida 32209 (United States); Department of Nuclear and Radiological/Biomedical Engineering, University of Florida, Gainesville, Florida 32611-8300 (United States)

    2011-02-15

    Purpose: To investigate the benefits and limitations of patient-phantom matching for determining organ dose during fluoroscopy guided interventions. Methods: In this study, 27 CT datasets representing patients of different sizes and genders were contoured and converted into patient-specific computational models. Each model was matched, based on height and weight, to computational phantoms selected from the UF hybrid patient-dependent series. In order to investigate the influence of phantom type on patient organ dose, Monte Carlo methods were used to simulate two cardiac projections (PA/left lateral) and two abdominal projections (RAO/LPO). Organ dose conversion coefficients were then calculated for each patient-specific and patient-dependent phantom and also for a reference stylized and reference hybrid phantom. The coefficients were subsequently analyzed for any correlation between patient-specificity and the accuracy of the dose estimate. Accuracy was quantified by calculating an absolute percent difference using the patient-specific dose conversion coefficients as the reference. Results: Patient-phantom matching was shown most beneficial for estimating the dose to heavy patients. In these cases, the improvement over using a reference stylized phantom ranged from approximately 50% to 120% for abdominal projections and for a reference hybrid phantom from 20% to 60% for all projections. For lighter individuals, patient-phantom matching was clearly superior to using a reference stylized phantom, but not significantly better than using a reference hybrid phantom for certain fields and projections. Conclusions: The results indicate two sources of error when patients are matched with phantoms: Anatomical error, which is inherent due to differences in organ size and location, and error attributed to differences in the total soft tissue attenuation. For small patients, differences in soft tissue attenuation are minimal and are exceeded by inherent anatomical differences

  2. Effectiveness and safety of varenicline as an aid to smoking cessation: results of an inter-Asian observational study in real-world clinical practice.

    Science.gov (United States)

    Wang, C; Cho, B; Xiao, D; Wajsbrot, D; Park, P W

    2013-05-01

    To evaluate the effectiveness and safety of varenicline for smoking cessation among Asian adult smokers in real-world clinical practice. A multicentre, prospective, non-comparative, observational study conducted in China, India, Philippines and Korea. Adult smokers, willing to make a quit attempt, who reached a joint decision with the investigators to take varenicline received 1 mg twice daily (after 1-week titration) for 12 weeks. No exclusion criteria were specified. Effectiveness evaluations included smoking abstinence status for the 7-day period before the Week 12 visit and the last observed study visit, determined by verbal reporting using a nicotine use inventory and carbon monoxide levels if part of usual practice (end of study only). The safety profile of varenicline was also assessed. Of 1377 subjects enrolled in the study, 1373 (99.7%) received varenicline and were evaluated for safety and effectiveness. Overall, 46.4% [95% confidence interval (CI): 43.73-49.07] of subjects successfully quit smoking by the end of the treatment phase at Week 12. When analysed by country, 57.1% (95% CI: 53.55-60.65) of subjects from China, 52.8% (95% CI: 45.21-60.25) of subjects from India, 51.0% (95% CI: 36.60-65.25) of subjects from Philippines and 20.3% (95% CI: 16.29-24.73) of subjects from Korea had quit smoking at Week 12. The most commonly reported treatment-related adverse event was nausea (11.5%). This study demonstrates the effectiveness and acceptable safety profile of varenicline for smoking cessation in a real-world setting among Asian populations, with results consistent with those of varenicline randomised controlled trials. © 2013 Blackwell Publishing Ltd.

  3. Asian American Health

    Science.gov (United States)

    Every racial or ethnic group has specific health concerns. Differences in the health of groups can result from Genetics Environmental factors Access to care Cultural factors On this page, you'll find links to health issues that affect Asian Americans.

  4. Computerized scheme for evaluating mammographic phantom images.

    Science.gov (United States)

    Asahara, Masaki; Kodera, Yoshie

    2012-03-01

    The authors developed a computer algorithm to automatically evaluate images of the American College of Radiology (ACR) mammography accreditation phantom. The developed algorithm consist of the edge detection of wax insert, nonuniformity correction of background, and correction for magnification and also calculate the cross-correlation coefficient by image matching technique. The algorithm additionally evaluates target shape for fibers, target contrast for speck groups, and target circularity for masses. To obtain an ideal template image without noise and spatial resolution loss, the wax insert containing the embedded test pattern was extracted from the phantom and radiographed. Two template images and ten test phantom images were prepared for this study. The results of evaluation using the algorithm outputs were compared with the averaged results of observer studies by six skilled observers. In comparing the results from the algorithm outputs with the results of observers, the authors found that the computer outputs were well correlated with the evaluations by observers, and they indicate the quality of the phantom image. The correlation coefficients between results of observer studies and two outputs of computer algorithm, i.e., the cross-correlation coefficient by template matching and indices of target shape for fibers, were 0.89 (95% confidence interval, 0.82-0.93; hereinafter the same) and 0.85 (0.76-0.91). The correlation coefficients between observer's results and two outputs: the cross-correlation coefficient and indices of target contrast for speck groups, were 0.83 (0.79-0.86) and 0.85 (0.81-0.88) and between observer's results and two outputs: the cross-correlation coefficient and indices of target circularity for masses, were 0.90 (0.84-0.94) and 0.87 (0.77-0.92). Image evaluation using the ACR phantom is indispensable in quality control of a mammography system. The proposed algorithm is useful for quality control and image evaluation of mammography

  5. Multimodal phantom of liver tissue.

    Directory of Open Access Journals (Sweden)

    Magdalena K Chmarra

    Full Text Available Medical imaging plays an important role in patients' care and is continuously being used in managing health and disease. To obtain the maximum benefit from this rapidly developing technology, further research is needed. Ideally, this research should be done in a patient-safe and environment-friendly manner; for example, on phantoms. The goal of this work was to develop a protocol and manufacture a multimodal liver phantom that is suitable for ultrasound, computed tomography, and magnetic resonance imaging modalities. The proposed phantom consists of three types of mimicked soft tissues: liver parenchyma, tumors, and portal veins, that are made of six ingredients: candle gel, sephadex®, agarose, glycerol, distilled water, and silicone string. The entire procedure is advantageous, since preparation of the phantom is simple, rather cost-effective, and reasonably quick - it takes around 2 days. Besides, most of the phantom's parts can be reused to manufacture a new phantom. Comparison of ultrasound images of real patient's liver and the developed phantom shows that the phantom's liver tissue and its structures are well simulated.

  6. Supernumerary phantom limb after stroke

    Science.gov (United States)

    Bakheit, A; Roundhill, S

    2005-01-01

    The perception of a phantom limb is commonly reported after amputations. However, only a few cases have been described after a stroke. This article presents a patient who reported a supernumerary phantom limb (pseudopolymelia) after spontaneous intracerebral haemorrhage and discusses the possible underlying mechanisms for this rare phenomenon. PMID:15749787

  7. Mapping phantom movement representations in the motor cortex of amputees.

    Science.gov (United States)

    Mercier, Catherine; Reilly, Karen T; Vargas, Claudia D; Aballea, Antoine; Sirigu, Angela

    2006-08-01

    Limb amputation results in plasticity of connections between the brain and muscles, with the cortical motor representation of the missing limb seemingly shrinking, to the presumed benefit of remaining body parts that have cortical representations adjacent to the now-missing limb. Surprisingly, the corresponding perceptual representation does not suffer a similar fate but instead persists as a phantom limb endowed with sensory and motor qualities. How can cortical reorganization after amputation be reconciled with the maintenance of a motor representation of the phantom limb in the brain? In an attempt to answer this question we explored the relationship between the cortical representation of the remaining arm muscles and that of phantom movements. Using transcranial magnetic stimulation (TMS) we systematically mapped phantom movement perceptions while simultaneously recording stump muscle activity in three above-elbow amputees. TMS elicited sensations of movement in the phantom hand when applied over the presumed hand area of the motor cortex. In one subject the amplitude of the perceived movement was positively correlated with the intensity of stimulation. Interestingly, phantom limb movements that the patient could not produce voluntarily were easily triggered by TMS, suggesting that the inability to voluntarily move the phantom is not equivalent to a loss of the corresponding movement representation. We suggest that hand movement representations survive in the reorganized motor area of amputees even when these cannot be directly accessed. The activation of these representations is probably necessary for the experience of phantom movement.

  8. An MRI digital brain phantom for validation of segmentation methods.

    Science.gov (United States)

    Alfano, Bruno; Comerci, Marco; Larobina, Michele; Prinster, Anna; Hornak, Joseph P; Selvan, S Easter; Amato, Umberto; Quarantelli, Mario; Tedeschi, Gioacchino; Brunetti, Arturo; Salvatore, Marco

    2011-06-01

    Knowledge of the exact spatial distribution of brain tissues in images acquired by magnetic resonance imaging (MRI) is necessary to measure and compare the performance of segmentation algorithms. Currently available physical phantoms do not satisfy this requirement. State-of-the-art digital brain phantoms also fall short because they do not handle separately anatomical structures (e.g. basal ganglia) and provide relatively rough simulations of tissue fine structure and inhomogeneity. We present a software procedure for the construction of a realistic MRI digital brain phantom. The phantom consists of hydrogen nuclear magnetic resonance spin-lattice relaxation rate (R1), spin-spin relaxation rate (R2), and proton density (PD) values for a 24 × 19 × 15.5 cm volume of a "normal" head. The phantom includes 17 normal tissues, each characterized by both mean value and variations in R1, R2, and PD. In addition, an optional tissue class for multiple sclerosis (MS) lesions is simulated. The phantom was used to create realistic magnetic resonance (MR) images of the brain using simulated conventional spin-echo (CSE) and fast field-echo (FFE) sequences. Results of mono-parametric segmentation of simulations of sequences with different noise and slice thickness are presented as an example of possible applications of the phantom. The phantom data and simulated images are available online at http://lab.ibb.cnr.it/. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. A Rat Body Phantom for Radiation Analysis

    Science.gov (United States)

    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.

  10. Validation of phantom-based harmonization for patient harmonization.

    Science.gov (United States)

    Panetta, Joseph V; Daube-Witherspoon, Margaret E; Karp, Joel S

    2017-07-01

    To improve the precision of multicenter clinical trials, several efforts are underway to determine scanner-specific parameters for harmonization using standardized phantom measurements. The goal of this study was to test the correspondence between quantification in phantom and patient images and validate the use of phantoms for harmonization of patient images. The National Electrical Manufacturers' Association image quality phantom with hot spheres was scanned on two time-of-flight PET scanners. Whole-body [18 F]-fluorodeoxyglucose (FDG)-PET scans were acquired of subjects on the same systems. List-mode events from spheres (diam.: 10-28 mm) measured in air on each scanner were embedded into the phantom and subject list-mode data from each scanner to create lesions with known uptake with respect to the local background in the phantom and each subject's liver and lung regions, as a proxy to characterize true lesion quantification. Images were analyzed using the contrast recovery coefficient (CRC) typically used in phantom studies and serving as a surrogate for the standardized uptake value used clinically. Postreconstruction filtering (resolution recovery and Gaussian smoothing) was applied to determine if the effect on the phantom images translates equivalently to subject images. Three postfiltering strategies were selected to harmonize the CRCmean or CRCmax values between the two scanners based on the phantom measurements and then applied to the subject images. Both the average CRCmean and CRCmax values for lesions embedded in the lung and liver in four subjects (BMI range 25-38) agreed to within 5% with the CRC values for lesions embedded in the phantom for all lesion sizes. In addition, the relative changes in CRCmean and CRCmax resulting from the application of the postfilters on the subject and phantom images were consistent within measurement uncertainty. Further, the root mean squared percent difference (RMSpd ) between CRC values on the two scanners

  11. Synthesis results from eight years of field testing insecticides against Asian citrus psyllid Diaphorina citri vector of huanglongbing: Considerations and Implications

    OpenAIRE

    Qureshi, Jawwad A.; Kostyk, Barry C.; Stansly, Philip A.

    2014-01-01

    Diaphorina citri also known as Asian citrus psyllid (ACP) vectors Candidatus Liberibacter asiaticus, causal organism of the Asian “huanglongbing” or citrus greening disease and therefore needs to be managed effectively.  Forty-three insecticides containing 39 active ingredients (a.i) recommended or experimental were tested during the growing season in foliar sprays (171 treatments, 35 a.i) targeted at flushing trees and soil applications (26 treatments, 6 a.i) to control ACP in citrus between...

  12. The prevalence of hepatitis C virus among people of South Asian origin in Glasgow - results from a community based survey and laboratory surveillance.

    Science.gov (United States)

    O'Leary, Maureen C; Sarwar, Mohammed; Hutchinson, Sharon J; Weir, Amanda; Schofield, Joe; McLeod, Allan; Cameron, Sheila; McTaggart, Christine; Banday, Shabir; Foster, Graham R; Ahmed, Syed; Fox, Ray; Mills, Peter R; Goldberg, David J; Anderson, Eleanor

    2013-01-01

    South Asians often present late with HCV or HBV related liver disease which could have been avoided with early diagnosis and subsequent treatment; however the prevalence of HCV/HBV among South Asians in Glasgow is not known. Accordingly, to inform the need for case finding among this group we aimed to examine the prevalence of Hepatitis C virus (HCV) among South Asians living in Glasgow. A community-based survey recruited individuals at six mosques and four community centres serving the South Asian community during 2009-2010; participants had predominantly never been HCV tested. Laboratory surveillance data involving all individuals tested for HCV during 1993-2009 were examined and South Asians were identified using Nam Pehchan software. In the community-based survey, 2.6% of 1288 participants tested HCV-antibody positive; the prevalence ranged from 0.6% among those born in the UK to 3.1% among those born in Pakistan. The odds of testing HCV-antibody positive were significantly raised among those who had surgery in South Asia (aOR: 5.0, 95% CI: 2.0-12.3) and had either medical/dental treatment or an injection in South Asia (aOR: 2.2, 95% CI: 1.0-5.0). Of 6404 South Asians identified from laboratory surveillance data, 9.3% tested HCV positive. An estimated 38% (330/870) of HCV-infected South Asians living in Glasgow remain undiagnosed. South Asians living in Glasgow, particularly those born outside the UK are at greater risk of HCV infection than the general population. Efforts to increase awareness and testing in this population are warranted. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Differences in food and nutrient intakes between Australian- and Asian-born women living in Australia: Results from the Australian Longitudinal Study on Women's Health.

    Science.gov (United States)

    Liu, Huaqing; Hall, John J; Xu, Xiaoyue; Mishra, Gita D; Byles, Julie E

    2017-12-27

    To determine differences in food and nutrient intakes between Australian- and Asian-born women living in Australia. Data were obtained from the Australian Longitudinal Study on Women's Health, including 6461 women born in Australia or Asia who completed food frequency questionnaires in 2001 and 2013. Diet was assessed using the Dietary Questionnaire for Epidemiological Studies version 2. Longitudinal generalised estimating-equation modelling was performed to determine the effect of country of birth and survey year on fruit and vegetable intake. Asian-born women ate more cereals, soybeans and fish but less vegetables, legumes, dairy, meat and meat products than Australian-born women both in 2001 and in 2013. Asian-born women ate less cereals, rice and noodles, meat and its products (P Asian-born women had a lower daily intake of fat, calcium, zinc, thiamin, riboflavin, folate and retinol compared with those born in Australia. Asian-born women living in Australia show different food and nutrient intakes from Australian-born women, although their diets tend to deviate from typical Asian characteristics and approach a Western diet. © 2017 Dietitians Association of Australia.

  14. Anisotropic diffusion phantoms based on microcapillaries

    Science.gov (United States)

    Vellmer, Sebastian; Edelhoff, Daniel; Suter, Dieter; Maximov, Ivan I.

    2017-06-01

    Diffusion MRI is an efficient and widely used technique for the investigation of tissue structure and organisation in vivo. Multiple phenomenological and biophysical diffusion models are intensively exploited for the analysis of the diffusion experiments. However, the verification of the applied diffusion models remains challenging. In order to provide a ;gold standard; and to assess the accuracy of the derived parameters and the limitations of the diffusion models, anisotropic diffusion phantoms with well known architecture are demanded. In the present work we built four anisotropic diffusion phantoms consisting of hollow microcapillaries with very small inner diameters of 5, 10 and 20 μ m and outer diameters of 90 and 150 μ m. For testing the suitability of these phantoms, we performed diffusion measurements on all of them and evaluated the resulting data with a set of popular diffusion models, such as diffusion tensor and diffusion kurtosis imaging, a two compartment model with intra- and extra-capillary water spaces using bi-exponential fitting, and time-dependent diffusion coefficients in Mitra's limit. The perspectives and limitations of these diffusion phantoms are presented and discussed.

  15. Diabetes in Asians

    Directory of Open Access Journals (Sweden)

    Eun-Jung Rhee

    2015-09-01

    Full Text Available The prevalence of diabetes is increasing globally, particularly in Asia. According to the 2013 Diabetes Atlas, an estimated 366 million people are affected by diabetes worldwide; 36% of those affected live in the Western Pacific region, with a significant proportion in East Asia. The reasons for this marked increase in the prevalence of diabetes can be extrapolated from several distinct features of the Asian region. First, the two most populated countries, China and India, are located in Asia. Second, Asians have experienced extremely rapid economic growth, including rapid changes in dietary patterns, during the past decades. As a result, Asians tend to have more visceral fat within the same body mass index range compared with Westerners. In addition, increased insulin resistance relative to reduced insulin secretory function is another important feature of Asian individuals with diabetes. Young age of disease onset is also a distinctive characteristic of these patients. Moreover, changing dietary patterns, such as increased consumption of white rice and processed red meat, contributes to the deteriorated lifestyle of this region. Recent studies suggest a distinctive responsiveness to novel anti-diabetic agents in Asia; however, further research and efforts to reverse the increasing prevalence of diabetes are needed worldwide.

  16. Efficacy and safety of once-daily inhaled umeclidinium/vilanterol in Asian patients with COPD: results from a randomized, placebo-controlled study

    Directory of Open Access Journals (Sweden)

    Zheng JP

    2015-09-01

    Full Text Available Jinping Zheng,1 Nanshan Zhong,1 Amy Newlands,2 Alison Church,3 Aik H Goh4 1State Key Lab of Respiratory Disease, National Clinical Research Centre of Respiratory Disease, First Affiliated Hospital of Guangzhou Medical University, Guangzhou, People’s Republic of China; 2GlaxoSmithKline, London, UK; 3GlaxoSmithKline, Research Triangle Park, NC, USA; 4GlaxoSmithKline, Shanghai, People’s Republic of ChinaBackground: Combination of the inhaled long-acting muscarinic antagonist umeclidinium (UMEC; GSK573719 with the long-acting β2-agonist vilanterol (VI is an approved maintenance treatment for COPD in the US and EU. We compared the efficacy and safety of UMEC/VI with placebo in patients with COPD of Asian ancestry.Patients and methods: In this 24-week, Phase III, multicenter, randomized, double-blind, placebo-controlled, parallel-group study, patients were randomized 1:1:1 to UMEC/VI 125/25 µg, UMEC/VI 62.5/25 µg, or placebo. The primary efficacy end point was trough forced expiratory volume in 1 second (FEV1 on day 169; secondary end points were Transition Dyspnea Index (TDI focal score at week 24 and weighted mean (WM FEV1 over 0–6 hours postdose on day 1. Additional end points and safety were also assessed.Results: Both UMEC/VI 125/25 µg and UMEC/VI 62.5/25 mg statistically significantly improved trough FEV1 at day 169 versus placebo (UMEC/VI 125/25 µg, 0.216 L, [95% confidence interval [CI] 0.175–0.257]; UMEC/VI 62.5/25 µg, 0.151 L, 95% CI 0.110–0.191; both P<0.001. Statistically significant improvements in TDI score were observed for both UMEC/VI groups versus placebo (UMEC/VI 125/25 µg, 0.9, 95% CI 0.3–1.4, P=0.002; UMEC/VI 62.5/25 µg, 0.7, 95% CI 0.1–1.2, P=0.016. On day 1, both UMEC/VI groups improved 0–6-hour WM FEV1 versus placebo (UMEC/VI 125/25 µg, 0.182 L 95% CI 0.161–0.203; UMEC/VI 62.5/25 µg, 0.160 L, 95% CI 0.139–0.181; both P<0.001. Statistically significant improvements for UMEC/VI groups

  17. Phantom limbs and neural plasticity.

    Science.gov (United States)

    Ramachandran, V S; Rogers-Ramachandran, D

    2000-03-01

    The study of phantom limbs has received tremendous impetus from recent studies linking changes in cortical topography with perceptual experience. Systematic psychophysical testing and functional imaging studies on patients with phantom limbs provide 2 unique opportunities. First, they allow us to demonstrate neural plasticity in the adult human brain. Second, by tracking perceptual changes (such as referred sensations) and changes in cortical topography in individual patients, we can begin to explore how the activity of sensory maps gives rise to conscious experience. Finally, phantom limbs also allow us to explore intersensory effects and the manner in which the brain constructs and updates a "body image" throughout life.

  18. A phase I/II trial of intraoperative breast radiotherapy in an Asian population: 5-year results of local control and cosmetic outcome.

    Science.gov (United States)

    Kawamura, Mariko; Itoh, Yoshiyuki; Sawaki, Masataka; Kikumori, Toyone; Tsunoda, Nobuyuki; Kamomae, Takeshi; Kubota, Seiji; Okada, Tohru; Nakahara, Rie; Ito, Junji; Hayashi, Hironori; Naganawa, Shinji

    2015-07-25

    To date, there are no reports of intraoperative radiotherapy (IORT) use with long-term follow up as a method of accelerated partial breast irradiation (APBI) in Asian countries. We initiated a prospective phase I/II clinical trial of IORT in Japan in 2007, and herein, we report the 5-year follow-up results. The following inclusion criteria were used for enrollment in the trial: (1) tumor size surgery, (3) age >50 years, and (4) negative margins after resection. In February 2009, the eligibility criteria were changed to include only patients with sentinel lymph node-negative disease. In phase I, the radiotherapy dose was escalated from 19 Gy/fr to 21 Gy/fr, incremented by 1 Gy per step, with 3 patients in each step. Doses were escalated after all patients in the preceding cohort had completed treatment and exhibited only grade 1 or 2 toxicities at a given dose level. The recommended phase II dose was set at 21 Gy at 90 % isodose. The primary endpoint was early toxicity. Secondary endpoints were long-term efficacy and late toxicity. In addition, Hypertrophic scarring was evaluated retrospectively as a cosmetic outcome by a radiation oncologist. Between December 2007 and March 2010, 32 women with breast cancer were enrolled in the trial. The median age was 65 years (51-80 years), and the median follow-up time was 6 years. No recurrence or metastasis was observed in any patient. Grade 2 fibrosis was detected in 3 patients as an acute adverse event and in 2 patients as a late adverse event. Ten patients developed a hypertrophic scar 1 year after the IORT; the number of patients decreased to 7 in the 3 years of follow-up. The first group of female Asian patients tolerated the treatment with IORT in this Phase I/II study and remained recurrence-free for more than 5 years after treatment. However, 24 % of the patients developed hypertrophic scarring, an event that is being further examined in our ongoing multi-center Phase II trial of IORT for early breast cancer.

  19. Young Asian Dutch constructing Asianness: Understanding the role of Asian popular culture

    OpenAIRE

    Kartosen, R.A.

    2016-01-01

    This doctoral thesis is about young Asian Dutch, panethnic Asian identities and identifications, and Asian/Asian Dutch popular culture. It addresses several pressing questions, including: why do young Asian Dutch, who were born and/or raised in the Netherlands, identify as Asian and construct Asian identities? What is the content or meaning of these Asian identities and identifications young Asian Dutch imagine? And how do these relate to young Asian Dutch’ Dutch and homeland identities and i...

  20. Hubungan Phantom Vibration Syndrome Terhadap Sleep Disorder dan Kondisi Stress

    Directory of Open Access Journals (Sweden)

    Ajeng Yeni Setianingrum

    2017-10-01

    Full Text Available Phantom vibration syndrome is a condition where a person would feel the sensation of vibration of a cell phone as if there were incoming notification but the fact is not. This research investigated the relationship between phantom vibration syndromes, sleep disorder and stress condition. Questionnaires were distributed to 120 participants with age range 18 to 23 years old. Data of participants showed that all of participants using a smart mobile phone and 24% of them have more than one cell phone. Time usage of cell phone is at least 1 hour. 23% of participants using a cell phone for social media activity, followed by 21% related to entertainment (music, video and games. The results showed a positive relationship between phantom vibration syndrome, sleep disorder and stress condition. Insomnia contributed a greater influence on stress condition. However, the phantom vibration syndrome is more directly affecting the sleep apnea compared to insomnia and stress condition. Therefore, the phantom vibration syndrome more affects stress condition indirectly, through sleep disorder (sleep apnea and insomnia. Consequently, phantom vibration syndrome has a strong relationship with stress condition at the time of the phantom vibration syndrome can cause sleep disorder.

  1. Individual differences in response to phantom limb movement therapy.

    Science.gov (United States)

    McAvinue, Laura P; Robertson, Ian H

    2011-01-01

    Phantom limb pain (PLP) is a distressing condition experienced by many amputees. The purpose of this study was to investigate whether motor imagery could be used to treat PLP. Four single case studies were conducted. The participants kept a pain diary in which they recorded the intensity of their PLP during a baseline period, general motor imagery training, phantom limb movement therapy and a follow-up period. Qualitative and quantitative (i.e. interrupted time series) analyses were employed to determine whether phantom limb movement therapy had a significant effect on PLP intensity. Phantom limb movement therapy significantly reduced intensity of PLP in one participant. One participant gained occasional relief by doing phantom limb movement therapy exercises but did not experience an overall reduction in PLP intensity. The third participant did not experience any relief and the fourth participant reported experiencing the re-emergence of an old pain. The results display individual differences in response to phantom limb movement therapy. Individual differences are discussed in the context of motor imagery ability and the phantom limb phenomenon as a multi-dimensional disorder.

  2. Realistic analytical polyhedral MRI phantoms.

    Science.gov (United States)

    Ngo, Tri M; Fung, George S K; Han, Shuo; Chen, Min; Prince, Jerry L; Tsui, Benjamin M W; McVeigh, Elliot R; Herzka, Daniel A

    2016-08-01

    Analytical phantoms have closed form Fourier transform expressions and are used to simulate MRI acquisitions. Existing three-dimensional (3D) analytical phantoms are unable to accurately model shapes of biomedical interest. The goal of this study was to demonstrate that polyhedral analytical phantoms have closed form Fourier transform expressions and can accurately represent 3D biomedical shapes. The Fourier transform of a polyhedron was implemented and its accuracy in representing faceted and smooth surfaces was characterized. Realistic anthropomorphic polyhedral brain and torso phantoms were constructed and their use in simulated 3D and two-dimensional (2D) MRI acquisitions was described. Using polyhedra, the Fourier transform of faceted shapes can be computed to within machine precision. Smooth surfaces can be approximated with increasing accuracy by increasing the number of facets in the polyhedron; the additional accumulated numerical imprecision of the Fourier transform of polyhedra with many faces remained small. Simulations of 3D and 2D brain and 2D torso cine acquisitions produced realistic reconstructions free of high frequency edge aliasing compared with equivalent voxelized/rasterized phantoms. Analytical polyhedral phantoms are easy to construct and can accurately simulate shapes of biomedical interest. Magn Reson Med 76:663-678, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  3. A dosimetric study on slab-pinewood-slab phantom for developing the heterogeneous chest phantom mimicking actual human chest

    Directory of Open Access Journals (Sweden)

    Om Prakash Gurjar

    2017-01-01

    Full Text Available The aim is to study the density, isodose depths, and doses at different points in slab-pinewood-slab (SPS phantom, solid phantom SP34 (made up of polystyrene, and chest level of actual patient for developing heterogeneous chest phantom mimicking thoracic region of human body. A 6 MV photon beam of field size of 10 cm×10 cm was directed perpendicular to the surface of computed tomography (CT images of chest level of patient, SPS phantom, and SP34 phantom. Dose was calculated using anisotropic analytical algorithm. Hounsfield units were used to calculate the density of each medium. Isodose depths in all the three sets of CT images were measured. Variations between planned doses on treatment planning system (TPS and measured on linear accelerator (LA were calculated for three points, namely, near slab-pinewood interfaces (6 and 18 cm depths and 10 cm depth in SPS phantom and at the same depths in SP34 phantom. Density of pinewood, SP34 slabs, chest wall, lung, and soft tissue behind lung was measured as 0.329 ± 0.08, 0.999 ± 0.02, 0.898 ± 0.02, 0.291 ± 0.12, and 1.002 ± 0.03 g/cc, respectively. Depths of 100% and 90% isodose curves in all the three sets of CT images were found to be similar. Depths of 80%, 70%, 60%, 50%, and 40% isodose lines in SPS phantom images were found to be equivalent to that in chest images, while it was least in SP34 phantom images. Variations in doses calculated at 6, 10, and 18 cm depths on TPS and measured on LA were found to be 0.36%, 1.65%, and 2.23%, respectively, in case of SPS phantom, while 0.24%, 0.90%, and 0.93%, respectively, in case of SP34 slab phantom. SPS phantom seemed equivalent to the chest level of human body. Dosimetric results of this study indicate that patient-specific quality assurance can be done using chest phantom mimicking thoracic region of human body, which has been fabricated using polystyrene and pinewood.

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

    Science.gov (United States)

    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.

  5. Immigration and generational trends in body mass index and obesity in the United States: results of the National Latino and Asian American Survey, 2002-2003.

    Science.gov (United States)

    Bates, Lisa M; Acevedo-Garcia, Dolores; Alegría, Margarita; Krieger, Nancy

    2008-01-01

    We examined patterns of body mass index (BMI) and obesity among a nationally representative sample of first-, second-, and third-generation Latinos and Asian Americans to reveal associations with nativity or country of origin. We used data from the National Latino and Asian American Survey (2002-2003) to generate nationally representative estimates of mean BMI and obesity prevalence and explored changes in the distribution of BMI by generational status. Analyses tested the association between generational status and BMI and examined whether this association varied by ethnicity, education, or gender. We found substantial heterogeneity in BMI and obesity by country of origin and an increase in BMI in later generations among most subgroups. The data suggest different patterns for Latinos and Asian Americans in the nature and degree of distributional changes in BMI with generational status in the United States. Generational status is associated with increased BMI and obesity among Latinos and Asian Americans. Aggregate estimates not accounting for nativity and country of origin may mask significant heterogeneity in the prevalence of obesity and patterns of distributional change, with implications for prevention strategies.

  6. Computerized scheme for evaluating mammographic phantom images

    Energy Technology Data Exchange (ETDEWEB)

    Asahara, Masaki; Kodera, Yoshie [Graduate School of Medical Sciences, Nagoya University, 1-1-20 Daiko-minami, Higashi-ku, Nagoya, Aichi 461-8673 (Japan) and Department of Radiology, Kagawa University Hospital, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0793 (Japan); Graduate School of Medical Sciences, Nagoya University, 1-1-20 Daiko-minami, Higashi-ku, Nagoya, Aichi 461-8673 (Japan)

    2012-03-15

    Purpose: The authors developed a computer algorithm to automatically evaluate images of the American College of Radiology (ACR) mammography accreditation phantom. Methods: The developed algorithm consist of the edge detection of wax insert, nonuniformity correction of background, and correction for magnification and also calculate the cross-correlation coefficient by image matching technique. The algorithm additionally evaluates target shape for fibers, target contrast for speck groups, and target circularity for masses. To obtain an ideal template image without noise and spatial resolution loss, the wax insert containing the embedded test pattern was extracted from the phantom and radiographed. Two template images and ten test phantom images were prepared for this study. The results of evaluation using the algorithm outputs were compared with the averaged results of observer studies by six skilled observers. Results: In comparing the results from the algorithm outputs with the results of observers, the authors found that the computer outputs were well correlated with the evaluations by observers, and they indicate the quality of the phantom image. The correlation coefficients between results of observer studies and two outputs of computer algorithm, i.e., the cross-correlation coefficient by template matching and indices of target shape for fibers, were 0.89 (95% confidence interval, 0.82-0.93; hereinafter the same) and 0.85 (0.76-0.91). The correlation coefficients between observer's results and two outputs: the cross-correlation coefficient and indices of target contrast for speck groups, were 0.83 (0.79-0.86) and 0.85 (0.81-0.88) and between observer's results and two outputs: the cross-correlation coefficient and indices of target circularity for masses, were 0.90 (0.84-0.94) and 0.87 (0.77-0.92). Conclusions: Image evaluation using the ACR phantom is indispensable in quality control of a mammography system. The proposed algorithm is useful for

  7. Young Asian Dutch constructing Asianness: Understanding the role of Asian popular culture

    NARCIS (Netherlands)

    Kartosen, R.A.

    2016-01-01

    This doctoral thesis is about young Asian Dutch, panethnic Asian identities and identifications, and Asian/Asian Dutch popular culture. It addresses several pressing questions, including: why do young Asian Dutch, who were born and/or raised in the Netherlands, identify as Asian and construct Asian

  8. Efficacy and safety of once-daily inhaled umeclidinium/vilanterol in Asian patients with COPD: results from a randomized, placebo-controlled study.

    Science.gov (United States)

    Zheng, Jinping; Zhong, Nanshan; Newlands, Amy; Church, Alison; Goh, Aik H

    2015-01-01

    Combination of the inhaled long-acting muscarinic antagonist umeclidinium (UMEC; GSK573719) with the long-acting β2-agonist vilanterol (VI) is an approved maintenance treatment for COPD in the US and EU. We compared the efficacy and safety of UMEC/VI with placebo in patients with COPD of Asian ancestry. In this 24-week, Phase III, multicenter, randomized, double-blind, placebo-controlled, parallel-group study, patients were randomized 1:1:1 to UMEC/VI 125/25 μg, UMEC/VI 62.5/25 μg, or placebo. The primary efficacy end point was trough forced expiratory volume in 1 second (FEV1) on day 169; secondary end points were Transition Dyspnea Index (TDI) focal score at week 24 and weighted mean (WM) FEV1 over 0-6 hours postdose on day 1. Additional end points and safety were also assessed. Both UMEC/VI 125/25 μg and UMEC/VI 62.5/25 μg statistically significantly improved trough FEV1 at day 169 versus placebo (UMEC/VI 125/25 μg, 0.216 L, [95% confidence interval [CI] 0.175-0.257]; UMEC/VI 62.5/25 μg, 0.151 L, 95% CI 0.110-0.191; both P<0.001). Statistically significant improvements in TDI score were observed for both UMEC/VI groups versus placebo (UMEC/VI 125/25 μg, 0.9, 95% CI 0.3-1.4, P=0.002; UMEC/VI 62.5/25 μg, 0.7, 95% CI 0.1-1.2, P=0.016). On day 1, both UMEC/VI groups improved 0-6-hour WM FEV1 versus placebo (UMEC/VI 125/25 μg, 0.182 L 95% CI 0.161-0.203; UMEC/VI 62.5/25 μg, 0.160 L, 95% CI 0.139-0.181; both P<0.001). Statistically significant improvements for UMEC/VI groups versus placebo were observed for rescue albuterol use at weeks 1-24 (puffs/day, both P<0.001). The incidence of adverse events was similar across groups. In Asian patients with COPD, once-daily UMEC/VI 125/25 μg and UMEC 62.5/25 μg resulted in clinically meaningful and statistically significant improvements in lung-function end points versus placebo. Symptomatic and quality of life measures also improved. The safety profile of UMEC/VI was consistent with previous studies.

  9. Freehand ultrasound calibration: phantom versus tracked pointer

    Science.gov (United States)

    Welch, Mattea; Andrea, Jennifer; Ungi, Tamas; Fichtinger, Gabor

    2013-03-01

    PURPOSE: Ultrasound-guided tracked navigation requires spatial calibration between the ultrasound beam and the tracker. We examined the reproducibility and accuracy of two popular open source calibration methods1 with a handheld linear ultrasound transducer. METHODS: A total of 10 calibrations were performed using (1) a double N-wire phantom with automatic image segmentation and registration; (2) and registration of landmark points collected with a tracked pointer. Reproducibility and accuracy were characterized by comparing the resulting transformation matrices, and by comparing ground truth landmark points. RESULTS: Transformation matrices calculated with an N-wire phantom showed a variance of X: 0.02 mm (in the direction of sound propagation), Y: 0.03 mm (in the direction of transducer elements) and Z: 0.21 mm (in the elevation direction). Transformation matrices obtained with tracked pointer showed a variance of X: 0.1 mm, Y: 0.10 mm and Z: 0.43 mm. Calibration accuracy was tested with ground truth cross wire points. The N-wire phantom provided a calibration with a distance from ground truth of X: 2.44 +/- 1.44 mm, Y: 1.21 +/- 0.88 mm, and Z: 1.12 +/- 0.82 mm. Tracked pointer calibration had a distance from the ground truth of X: 0.23 +/- 0.16 mm, Y: 0.62 +/- 0.31 mm, and Z: 0.45 +/- 0.33 mm. Distance from ground truth was significantly less (ptracked pointer method in all directions. CONCLUSION: Calibration using a tracked pointer had a slightly greater variance; however it showed better accuracy over calibrations calculated with N-wire phantoms.

  10. Bounds for Asian basket options

    Science.gov (United States)

    Deelstra, Griselda; Diallo, Ibrahima; Vanmaele, Michèle

    2008-09-01

    In this paper we propose pricing bounds for European-style discrete arithmetic Asian basket options in a Black and Scholes framework. We start from methods used for basket options and Asian options. First, we use the general approach for deriving upper and lower bounds for stop-loss premia of sums of non-independent random variables as in Kaas et al. [Upper and lower bounds for sums of random variables, Insurance Math. Econom. 27 (2000) 151-168] or Dhaene et al. [The concept of comonotonicity in actuarial science and finance: theory, Insurance Math. Econom. 31(1) (2002) 3-33]. We generalize the methods in Deelstra et al. [Pricing of arithmetic basket options by conditioning, Insurance Math. Econom. 34 (2004) 55-57] and Vanmaele et al. [Bounds for the price of discrete sampled arithmetic Asian options, J. Comput. Appl. Math. 185(1) (2006) 51-90]. Afterwards we show how to derive an analytical closed-form expression for a lower bound in the non-comonotonic case. Finally, we derive upper bounds for Asian basket options by applying techniques as in Thompson [Fast narrow bounds on the value of Asian options, Working Paper, University of Cambridge, 1999] and Lord [Partially exact and bounded approximations for arithmetic Asian options, J. Comput. Finance 10 (2) (2006) 1-52]. Numerical results are included and on the basis of our numerical tests, we explain which method we recommend depending on moneyness and time-to-maturity.

  11. Phantom dark ghost in Einstein-Cartan gravity

    Science.gov (United States)

    Chang, Yu-Chiao; Bouhmadi-López, Mariam; Chen, Pisin

    2017-05-01

    A class of dynamical dark energy models is constructed through an extended version of fermion fields corresponding to phantom dark ghost spinors, which are spin 1/2 with mass dimension 1. We find that if these spinors interact with torsion fields in a homogeneous and isotropic universe, then it does not imply any future dark energy singularity or any abrupt event, though the fermion has a negative kinetic energy. In fact, the equation of state of this dark energy model will asymptotically approach the value w=-1 from above without crossing the phantom divide and inducing therefore a de Sitter state. Consequently, we expect the model to be stable because no real phantom fields will be created. At late time, the torsion fields will vanish as the corresponding phantom dark ghost spinors dilute. As would be expected, intuitively, this result is unaffected by the presence of cold dark matter although the proof is not as straightforward as in general relativity.

  12. Fabrication and characterization of biological tissue phantoms with embedded nanoparticles

    Science.gov (United States)

    Skaptsov, A. A.; Ustalkov, S. O.; Mohammed, A. H. M.; Savenko, O. A.; Novikova, A. S.; Kozlova, E. A.; Kochubey, V. I.

    2017-11-01

    Phantoms are imitations of biological tissue, which are used for modelling of the light propagation in biological tissues. Carrying out any biophysical experiments requires an indispensable constancy of the initial experiment conditions. The use of solid undegradable phantoms is the basis to obtain reliable reproducible experimental results. The fabrication of biological tissues phantoms containing high absorbance or fluorescence nanoparticles and corresponding to specific mechanical, optical properties is an actual task. This work describes development, fabrication and characterization of such solid tissue phantoms with embedded CdSe/ZnS quantum dots, gold and upconversion nanoparticles. Luminescence of samples with CdSe/ZnS quantum dots and upconversion nanoparticles were recorded. A sample of gold nanorods was analyzed using thermal gravimetric analysis. It can be concluded that the samples are well suited for experiments on laser thermolysis.

  13. Phantom dark ghost in Einstein-Cartan gravity

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Yu-Chiao [National Taiwan University, Department of Physics, Taipei (China); National Taiwan University, LeCosPA, Taipei (China); Bouhmadi-Lopez, Mariam [University of the Basque Country UPV/EHU, Department of Theoretical Physics, P.O. Box 644, Bilbao (Spain); Basque Foundation for Science, IKERBASQUE, Bilbao (Spain); Chen, Pisin [National Taiwan University, Department of Physics, Taipei (China); National Taiwan University, LeCosPA, Taipei (China); National Taiwan University, Graduate Institute of Astrophysics, Taipei (China); SLAC National Accelerator Laboratory, Stanford University, Kavli Institute for Particle Astrophysics and Cosmology, Stanford, CA (United States)

    2017-05-15

    A class of dynamical dark energy models is constructed through an extended version of fermion fields corresponding to phantom dark ghost spinors, which are spin 1/2 with mass dimension 1. We find that if these spinors interact with torsion fields in a homogeneous and isotropic universe, then it does not imply any future dark energy singularity or any abrupt event, though the fermion has a negative kinetic energy. In fact, the equation of state of this dark energy model will asymptotically approach the value w = -1 from above without crossing the phantom divide and inducing therefore a de Sitter state. Consequently, we expect the model to be stable because no real phantom fields will be created. At late time, the torsion fields will vanish as the corresponding phantom dark ghost spinors dilute. As would be expected, intuitively, this result is unaffected by the presence of cold dark matter although the proof is not as straightforward as in general relativity. (orig.)

  14. Does multi-slice CT provide reliable attenuation values if measured with low slice thickness and low tube current? Results of a phantom study; Sind mit der Mehrschicht-Computertomografie Dichtemessungen auch bei geringer Schichtdicke und niedrigem Roehrenstrom verlaesslich?

    Energy Technology Data Exchange (ETDEWEB)

    Kirchhof, K.; Bohndorf, K. [Klinik fuer Diagnostische Radiologie und Neuroradiologie, Klinikum Augsburg (Germany); Welzel, T. [Abt. klinische Radiologie, Radiologische Universitaetsklinik Heidelberg (Germany); Wagner, T. [Pathologisches Inst., Klinikum Augsburg (Germany); Behr, W. [Inst. fuer Laboratoriumsmedizin, Mikrobiologie und Umwelthygiene, Klinikum Augsburg (Germany)

    2008-01-15

    Purpose: to test whether CT with low slice thickness and low tube current provides reliable attenuation measurements. Materials and methods: using multi-slice CT and a phantom, we measured the attenuation values of thrombi with different proportions of erythrocytes, using a slice thickness of 1.25 mm, 2.5 mm, and 5 mm with tube currents of 200 mA, 300 mA, and 400 mA and a slice thickness of 0.625 mm with tube currents of 150 mA, 175 mA, and 200 mA. Differences in attenuation values and pixel noise between the three thrombi for tube current and slice thickness were statistically analyzed. Results: the attenuation values of all thrombi increased (p < 0.05) when the slice thickness decreased using a tube current of 200 mA or when the tube current decreased using a slice thickness of 1.25 mm. With higher tube currents and thicker slices, the CT values depended on the type of thrombus and the slice thickness. In slices with a thickness of 0.625 mm, the CT values decreased with the tube current in the mixed thrombus with a low proportion of erythrocytes and in the red thrombus (p < 0.05). The maximal difference in mean attenuation values was 4.3 HU with a slice thickness of 0.625 mm and 2.2 HU with a slice thickness of 1.25 mm. The pixel noise increased as the slice thickness decreased (p < 0.05) with the exception of the red thrombus, if reduced to 0.625 mm. The pixel noise also increased as the tube current decreased (p < 0.05) except in mixed thrombi measured with 0.625 mm. The maximal difference in mean standard deviation was 1.8 HU with a slice thickness of 1.25 mm. (orig.)

  15. Dedicated phantom materials for spectral radiography and CT.

    Science.gov (United States)

    Shikhaliev, Polad M

    2012-03-21

    As x-ray imaging technology moves from conventional radiography and computed tomography (CT) to spectral radiography and CT, dedicated phantom materials are needed for spectral imaging. The spectral phantom materials should accurately represent the energy-dependent mass-attenuation coefficients of different types of tissues. Although tissue-equivalent phantom materials were previously developed for CT and radiation therapy applications, these materials are suboptimal for spectral radiography and CT; they are not compatible with contrast agents, do not represent many of the tissue types and do not provide accurate values of attenuation characteristics of tissue. This work provides theoretical framework and a practical method for developing tissue-equivalent spectral phantom materials with a required set of parameters. The samples of the tissue-equivalent spectral phantom materials were developed, tested and characterized. The spectral phantom materials were mixed with iodine, gold and calcium contrast agents and evaluated. The materials were characterized by CT imaging and x-ray transmission experiments. The fabricated materials had nearly identical densities, mass attenuation coefficients, effective atomic numbers and electron densities as compared to corresponding tissue materials presented in the ICRU-44 report. The experimental results have shown good volume uniformity and inter-sample uniformity (repeatability of sample fabrication) of the fabricated materials. The spectral phantom materials were fabricated under laboratory conditions from readily available and inexpensive components. It was concluded that the presented theoretical framework and fabrication method of dedicated spectral phantom materials could be useful for researchers and developers working in the new area of spectral radiography and CT. Independently, the results could also be useful for other applications, such as radiation therapy. © 2012 Institute of Physics and Engineering in Medicine

  16. Two-layer heterogeneous breast phantom for photoacoustic imaging

    Science.gov (United States)

    Jia, Congxian; Vogt, William C.; Wear, Keith A.; Pfefer, T. Joshua; Garra, Brian S.

    2017-10-01

    Photoacoustic tomography (PAT) is emerging as a potentially important aid for breast cancer detection. Well-validated tissue-simulating phantoms are needed for objective, quantitative, and physically realistic testing for system development. Prior reported PAT phantoms with homogenous structures do not incorporate the irregular layered structure of breast tissue. To assess the impact of this simplification, we design and construct two-layer breast phantoms incorporating vessel-simulating inclusions and realistic undulations at the fat/fibroglandular tissue interface. The phantoms are composed of custom poly(vinyl chloride) plastisol formulations mimicking the acoustic properties of two breast tissue types and tissue-relevant similar optical properties. Resulting PAT images demonstrate that in tissue with acoustic heterogeneity, lateral size of imaging targets is sensitive to the choice of sound speed in image reconstruction. The undulating boundary can further degrade a target's lateral size due to sound speed variation in tissue and refraction of sound waves at the interface. The extent of this degradation is also influenced by the geometric relationship between an absorber and the boundary. Results indicate that homogeneous phantom matrixes may underestimate the degradation of PAT image quality in breast tissue, whereas heterogeneous phantoms can provide more realistic testing through improved reproduction of spatial variations in physical properties.

  17. Liver phantom for quality control and training in nuclear medicine

    Science.gov (United States)

    Lima Ferreira, Fernanda Carla; Souza, Divanizia do Nascimento

    2011-10-01

    In nuclear medicine, liver scintigraphy aims to verify organ function based on the radionuclide concentration in the liver and bile flow and is also used to detect tumors. Therefore it is necessary to perform quality control tests in the gamma camera before running the exam to prevent false results. Quality control tests of the gamma camera should thus be performed before running the exam to prevent false results. Such tests generally use radioactive material inside phantoms for evaluation of gamma camera parameters in quality control procedures. Phantoms can also be useful for training doctors and technicians in nuclear medicine procedures. The phantom proposed here has artifacts that simulate nodules; it may take on different quantities, locations and sizes and it may also be mounted without the introduction of nodules. Thus, its images may show hot or cold nodules or no nodules. The phantom consists of acrylic plates hollowed out in the centre, with the geometry of an adult liver. Images for analyses of simulated liver scintigraphy were obtained with the detector device at 5 cm from the anterior surface of the phantom. These simulations showed that this object is suitable for quality control in nuclear medicine because it was possible to visualize artifacts larger than 7.9 mm using a 256×256 matrix and 1000 kcpm. The phantom constructed in this work will also be useful for training practitioners and technicians in order to prevent patients from repeat testing caused by error during examinations.

  18. Materials for phantoms for terahertz pulsed imaging

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Gillian C [Academic Unit of Medical Physics, University of Leeds, Wellcome Wing, Leeds General Infirmary, Great George Street, Leeds, LS1 3EX (United Kingdom); Berry, Elizabeth [Academic Unit of Medical Physics, University of Leeds, Wellcome Wing, Leeds General Infirmary, Great George Street, Leeds, LS1 3EX (United Kingdom); Smye, Stephen W [Department of Medical Physics and Engineering, Leeds Teaching Hospitals NHS Trust, St James University Hospital, Leeds, LS9 7TF (United Kingdom); Brettle, David S [Department of Medical Physics and Engineering, Leeds Teaching Hospitals NHS Trust, St James University Hospital, Leeds, LS9 7TF (United Kingdom)

    2004-11-07

    Phantoms are commonly used in medical imaging for quality assurance, calibration, research and teaching. They may include test patterns or simulations of organs, but in either case a tissue substitute medium is an important component of the phantom. The aim of this work was to identify materials suitable for use as tissue substitutes for the relatively new medical imaging modality terahertz pulsed imaging. Samples of different concentrations of the candidate materials TX151 and napthol green dye were prepared, and measurements made of the frequency-dependent absorption coefficient (0.5 to 1.5 THz) and refractive index (0.5 to 1.0 THz). These results were compared qualitatively with measurements made in a similar way on samples of excised human tissue (skin, adipose tissue and striated muscle). Both materials would be suitable for phantoms where the dominant mechanism to be simulated is absorption ({approx}100 cm{sup -1} at 1 THz) and where simulation of the strength of reflections from boundaries is not important; for example, test patterns for spatial resolution measurements. Only TX151 had a frequency-dependent refractive index close to that of tissue, and could therefore be used to simulate the layered structure of skin, the complexity of microvasculature or to investigate frequency-dependent interference effects that have been noted in terahertz images. (note)

  19. A Clinical Evaluation of Postamputation Phenomena Including Phantom Limb Pain after Lower Limb Amputation in Dysvascular Patients.

    Science.gov (United States)

    Richardson, Cliff; Crawford, Kath; Milnes, Karen; Bouch, Elizabeth; Kulkarni, Jai

    2015-08-01

    To explore the effects of phantom phenomena on a group of dysvascular lower limb amputees. This was a cross-sectional study of dysvascular lower limb amputees. A modified version of the phantom phenomena questionnaire was used to measure the prevalence of phantom phenomena and the effects of those phenomena on daily life. Eighty-nine amputees were recruited. The majority were inpatients (72%) and male (72%). Most had pain before amputation (83%). Sixty-three percent had phantom limb pain. No associations were found between phantom limb pain and preamputation pain (p = .397). Phantom limb pain was present immediately on waking from amputation in 23%. Phantom limb pain is highly fluctuant. It is more likely that phantom limb pain was present with more time passed since amputation (p = .002). Outpatients with unhealed wounds were less likely to have phantom limb pain (p = .007). The effects of postamputation phenomena include sleep loss and social restrictions. These results challenge the belief that phantom limb pain reduces over time as more outpatients reported phantom limb pain than inpatients. Preamputation pain is not linked to the presence of phantom limb pain. The fluctuant nature of phantom limb pain makes its treatment complex. Some may wish intensity to reduce, whereas others may prefer to reduce the number of episodes or duration of each episode instead. More research is needed to clarify the needs of amputees in relation to the postamputation phenomena. Copyright © 2015 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

  20. Prevalent hallucinations during medical internships: phantom vibration and ringing syndromes.

    Directory of Open Access Journals (Sweden)

    Yu-Hsuan Lin

    Full Text Available BACKGROUND: Phantom vibration syndrome is a type of hallucination reported among mobile phone users in the general population. Another similar perception, phantom ringing syndrome, has not been previously described in the medical literature. METHODS: A prospective longitudinal study of 74 medical interns (46 males, 28 females; mean age, 24.8±1.2 years was conducted using repeated investigations of the prevalence and associated factors of phantom vibration and ringing. The accompanying symptoms of anxiety and depression were evaluated with the Beck Anxiety and Depression Inventories before the internship began, and again at the third, sixth, and twelfth internship months, and two weeks after the internship ended. RESULTS: The baseline prevalence of phantom vibration was 78.1%, which increased to 95.9% and 93.2% in the third and sixth internship months. The prevalence returned to 80.8% at the twelfth month and decreased to 50.0% 2 weeks after the internship ended. The baseline prevalence of phantom ringing was 27.4%, which increased to 84.9%, 87.7%, and 86.3% in the third, sixth, and twelfth internship months, respectively. This returned to 54.2% two weeks after the internship ended. The anxiety and depression scores also increased during the internship, and returned to baseline two weeks after the internship. There was no significant correlation between phantom vibration/ringing and symptoms of anxiety or depression. The incidence of both phantom vibration and ringing syndromes significantly increased during the internship, and subsequent recovery. CONCLUSION: This study suggests that phantom vibration and ringing might be entities that are independent of anxiety or depression during evaluation of stress-associated experiences during medical internships.

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

    Energy Technology Data Exchange (ETDEWEB)

    Ehler, E; Higgins, P; Dusenbery, K [University of Minnesota, Minneapolis, MN (United States)

    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.

  2. Changing Asian American Stereotypes

    Science.gov (United States)

    Salvador-Burris, Juanita

    1978-01-01

    Social science literature on stereotypes is reviewed. Negative stereotypes of Asian Americans are examined and their relationship to Asian American political and economic status and self image is discussed. Specific actions to counter these stereotypes are advocated. (GC)

  3. Obesity and Asian Americans

    Science.gov (United States)

    ... and Data > Minority Population Profiles > Asian American > Obesity Obesity and Asian Americans Non-Hispanic whites are 60% ... youthonline . [Accessed 08/18/2017] HEALTH IMPACT OF OBESITY People who are overweight are more likely to ...

  4. Glaucoma in Asian Populations

    Science.gov (United States)

    ... Involved News About Us Donate In This Section Glaucoma In Asian Populations email Send this article to ... lower than in their Asian counterparts. Normal Tension Glaucoma affects Japanese Japanese populations, however, have a substantially ...

  5. Asian Australian Literatures

    OpenAIRE

    Madsen, Deborah Lea

    2007-01-01

    This article offers an overview of the range of Asian-Australian writers, within the context of changing historical and political conditions, as well as the complexity of defining a single category of literature written by Australians of Asian heritage. Such a category is difficult to define in strictly nationalistic terms as ‘Asian Australian literature’: where Australian literature is the controlling noun and ‘Asian’ functions as an adjective. Some Asian Australian writers are Australian-bo...

  6. Fabrication of tissue phantoms with embedded CdSe/ZnS quantum dots, gold and upconversion nanoparticles

    Science.gov (United States)

    Skaptsov, Alexander A.; Ustalkov, Sergey O.; Savenko, Olga A.; Novikova, Anastasia S.; Kozlova, Ekaterina A.; Kochubey, Vyacheslav I.

    2017-03-01

    Phantoms are an imitation of biological tissue, which are physically modeling the propagation of light in biological tissues. They are required for different purposes, and also repeatability of results is achieved with it. So the fabrication of solid tissue phantoms containing high absorb or luminescence nanoparticles is actual problems for experimenters. The work describes fabrication processing and characteristics of solid tissue phantoms.

  7. Did opening of the South China Sea impact development of the Asian Monsoon? Results from Oligocene microfossils, IODP Site U1435, northern South China Sea

    Science.gov (United States)

    Kulhanek, Denise K.; Su, Xin; Li, Qianyu; Gregory, Mitch; Warny, Sophie; Clift, Peter D.

    2016-04-01

    Development of the Asian Monsoon is linked to uplift of the Himalayas and Tibetan Plateau in the Cenozoic, with good evidence for a strong monsoon system by the late Oligocene to early Miocene (e.g., Guo et al., 2002; Clift et al., 2008). However, Licht et al. (2014) suggested the presence of an Asian Monsoon in the late Eocene. Recent scientific ocean drilling in the Indian Ocean and surrounding marginal seas gives us the opportunity to test this hypothesis with newly recovered Paleogene sediment cores. International Ocean Discovery Program Expedition 349 to the South China Sea recovered a 30 m section of primarily lower Oligocene nannofossil-rich claystone at Site U1435, located near the northern continent/ocean boundary. A thick sandstone unit devoid of typical marine microfossils underlies the marine claystone. The sandstone is interpreted as a deltaic or restricted marine deposit and is dated to the Eocene based on the presence of organic-walled palynomorphs, suggesting that a hiatus of several million years likely separates the sandstone below from the Oligocene marine claystone. This hiatus is interpreted as the breakup unconformity, with paleodepths in the South China Sea increasing during the Oligocene. Thus, this claystone should record if opening of the South China Sea during the early Oligocene influenced development of the Asian Monsoon. Combined calcareous nannofossil and planktonic foraminifer biostratigraphy indicates that the 30 m section is primarily early Oligocene in age (~33.5-30 Ma) and was deposited on the middle slope, with paleodepths >500 m. Stable oxygen isotopes from planktonic foraminifers become heavier up-hole, suggestive of cooling/deepening in the region, whereas carbon isotopes record variable conditions with no distinct maxima or minima. Calcareous nannoplankton primarily live in the upper 50 m of the ocean and are sensitive to sea-surface temperature and nutrient conditions, thus making them useful recorders of paleoceanographic

  8. Phantom pain : A sensitivity analysis

    NARCIS (Netherlands)

    Borsje, Susanne; Bosmans, JC; Van der Schans, CP; Geertzen, JHB; Dijkstra, PU

    2004-01-01

    Purpose : To analyse how decisions to dichotomise the frequency and impediment of phantom pain into absent and present influence the outcome of studies by performing a sensitivity analysis on an existing database. Method : Five hundred and thirty-six subjects were recruited from the database of an

  9. Asian American college women's body image: a pilot study.

    Science.gov (United States)

    Lau, Allison S M; Lum, Sharilyn K; Chronister, Krista M; Forrest, Linda

    2006-04-01

    The purpose of this study was to examine the effects of values acculturation and the influence of media on Asian American college women's overall body image. A sample of 59 Asian American women from two large universities completed self-report surveys, which included questions regarding values acculturation, media internalization, and overall body satisfaction. Results showed that Asian American women who identified more strongly with traditional Asian values reported higher levels of body image dissatisfaction. Further, Asian American women who reported higher internalization of media portrayals of beauty ideals reported higher body image dissatisfaction. Research and clinical recommendations are made to enhance psychologists' understanding of Asian American women's body image and acculturation.

  10. Tachyonic field interacting with scalar (phantom) field

    OpenAIRE

    Chattopadhyay, Surajit; Debnath, Ujjal

    2009-01-01

    In this letter, we have considered the universe is filled with the mixture of tachyonic field and scalar or phantom field. If the tachyonic field interacts with scalar or phantom field, the interaction term decays with time and the energy for scalar field is transferred to tachyonic field or the energy for phantom field is transferred to tachyonic field. The tachyonic field and scalar field potentials always decrease, but phantom field potential always increases.

  11. Agency over Phantom Limb Enhanced by Short-Term Mirror Therapy.

    Science.gov (United States)

    Imaizumi, Shu; Asai, Tomohisa; Koyama, Shinichi

    2017-01-01

    Most amputees experience phantom limb, whereby they feel that the amputated limb is still present. In some cases, these experiences include pain that can be alleviated by "mirror therapy." Mirror therapy consists of superimposing a mirrored image of the moving intact limb onto the phantom limb. This therapy provides a closed loop between the motor command to the amputated limb and its predicted visual feedback. This loop is also involved in the sense of agency, a feeling of controlling one's own body. However, it is unclear how mirror therapy is related to the sense of agency over a phantom limb. Using mirror therapy, we investigated phantom limb pain and the senses of agency and ownership (i.e., a feeling of having one's own body) of the phantom limb. Nine upper-limb amputees, five of whom reported recent phantom limb pain, underwent a single 15-min trial of mirror therapy. Before and after the trial, the participants completed a questionnaire regarding agency, ownership, and pain related to their phantom limb. They reported that the sense of agency over the phantom limb increased following the mirror therapy trial, while the ownership slightly increased but not as much as did the agency. The reported pain did not change; that is, it was comparably mild before and after the trial. These results suggest that short-term mirror therapy can, at least transiently, selectively enhance the sense of agency over a phantom limb, but may not alleviate phantom limb pain.

  12. The Impact of Racial Identity, Ethnic Identity, Asian Values, and Race-Related Stress on Asian Americans and Asian International College Students' Psychological Well-Being

    Science.gov (United States)

    Iwamoto, Derek Kenji; Liu, William Ming

    2010-01-01

    The present study investigated the direct and moderating effects of racial identity, ethnic identity, Asian values, and race-related stress on positive psychological well-being among 402 Asian American and Asian international college students. Results revealed that the racial identity statuses Internalization, Immersion-Emersion, Dissonance, Asian…

  13. Phantom Recollection of Bridging and Elaborative Inferences

    Science.gov (United States)

    Singer, Murray; Spear, Jackie

    2015-01-01

    The phantom recollection model is a multiprocess analysis according to which memory judgments are collaboratively supported by one's recollection of an item in its context, a vaguer sense of stimulus familiarity, and the phantom recollection of the substance and even perceptual details of unstudied but related lures. Phantom recollection has…

  14. Agency over a phantom limb and electromyographic activity on the stump depend on visuomotor synchrony: a case study.

    Science.gov (United States)

    Imaizumi, Shu; Asai, Tomohisa; Kanayama, Noriaki; Kawamura, Mitsuru; Koyama, Shinichi

    2014-01-01

    Most patients, post-amputation, report the experience of a phantom limb. Some even sense voluntary movements when viewing a mirror image of the intact limb superimposed onto the phantom limb. While delayed visual feedback of an action is known to reduce a sense of agency, the effect of delayed visual feedback on phantom motor sensation (i.e., sense of controlling a phantom limb) has not been examined. Using a video-projection system, we examined the effect of delayed visual feedback on phantom motor sensation in an upper-limb amputee (male; left upper-limb amputation). He was instructed to view mirrored video images of his intact hand clasping and unclasping during a phantom limb movement. He then rated the intensity of the phantom motor sensation. Three types of hand movement images were presented as follows: synchronous, asynchronous with a 250-ms delay, and asynchronous with a 500-ms delay. Results showed that phantom motor sensation decreased when the image was delayed by 250 and 500 ms. However, when we instructed the patient to adjust the phase of phantom limb movement to that of the image with a 500-ms delay, phantom motor sensation increased. There was also a positive correlation between intensity of phantom motor sensation and electromyographic (EMG) activity on deltoids at the patient's stump. These results suggest that phantom motor sensation and EMG activity on the stump depend on visuomotor synchrony and top-down effects.

  15. Agency over a phantom limb and electromyographic activity on the stump depend on visuomotor synchrony: a case study

    Science.gov (United States)

    Imaizumi, Shu; Asai, Tomohisa; Kanayama, Noriaki; Kawamura, Mitsuru; Koyama, Shinichi

    2014-01-01

    Most patients, post-amputation, report the experience of a phantom limb. Some even sense voluntary movements when viewing a mirror image of the intact limb superimposed onto the phantom limb. While delayed visual feedback of an action is known to reduce a sense of agency, the effect of delayed visual feedback on phantom motor sensation (i.e., sense of controlling a phantom limb) has not been examined. Using a video-projection system, we examined the effect of delayed visual feedback on phantom motor sensation in an upper-limb amputee (male; left upper-limb amputation). He was instructed to view mirrored video images of his intact hand clasping and unclasping during a phantom limb movement. He then rated the intensity of the phantom motor sensation. Three types of hand movement images were presented as follows: synchronous, asynchronous with a 250-ms delay, and asynchronous with a 500-ms delay. Results showed that phantom motor sensation decreased when the image was delayed by 250 and 500 ms. However, when we instructed the patient to adjust the phase of phantom limb movement to that of the image with a 500-ms delay, phantom motor sensation increased. There was also a positive correlation between intensity of phantom motor sensation and electromyographic (EMG) activity on deltoids at the patient’s stump. These results suggest that phantom motor sensation and EMG activity on the stump depend on visuomotor synchrony and top-down effects. PMID:25120449

  16. Agency over a phantom limb and electromyographic activity on the stump depend on visuomotor synchrony: a case study

    Directory of Open Access Journals (Sweden)

    Shu eImaizumi

    2014-07-01

    Full Text Available Most patients, post-amputation, report the experience of a phantom limb. Some even sense voluntary movements when viewing a mirror image of the intact limb superimposed onto the phantom limb. While delayed visual feedback of an action is known to reduce a sense of agency, the effect of delayed visual feedback on phantom motor sensation (i.e., sense of controlling a phantom limb has not been examined. Using a video-projection system, we examined the effect of delayed visual feedback on phantom motor sensation in an upper-limb amputee (male; left upper-limb amputation. He was instructed to view mirrored video images of his intact hand clasping and unclasping during a phantom limb movement. He then rated the intensity of the phantom motor sensation. Three types of hand movement images were presented as follows: synchronous, asynchronous with a 250-ms delay, and asynchronous with a 500-ms delay. Results showed that phantom motor sensation decreased when the image was delayed by 250 and 500 ms. However, when we instructed the patient to adjust the phase of phantom limb movement to that of the image with a 500-ms delay, phantom motor sensation increased. There was also a positive correlation between intensity of phantom motor sensation and electromyographic activity on deltoids at the patient’s stump. These results suggest that phantom motor sensation and electromyographic activity on the stump depend on visuomotor synchrony and top-down effects.

  17. Technical Note: Characterization of custom 3D printed multimodality imaging phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Bieniosek, Matthew F. [Department of Electrical Engineering, Stanford University, 350 Serra Mall, Stanford, California 94305 (United States); Lee, Brian J. [Department of Mechanical Engineering, Stanford University, 440 Escondido Mall, Stanford, California 94305 (United States); Levin, Craig S., E-mail: cslevin@stanford.edu [Departments of Radiology, Physics, Bioengineering and Electrical Engineering, Stanford University, 300 Pasteur Dr., Stanford, California 94305-5128 (United States)

    2015-10-15

    Purpose: Imaging phantoms are important tools for researchers and technicians, but they can be costly and difficult to customize. Three dimensional (3D) printing is a widely available rapid prototyping technique that enables the fabrication of objects with 3D computer generated geometries. It is ideal for quickly producing customized, low cost, multimodal, reusable imaging phantoms. This work validates the use of 3D printed phantoms by comparing CT and PET scans of a 3D printed phantom and a commercial “Micro Deluxe” phantom. This report also presents results from a customized 3D printed PET/MRI phantom, and a customized high resolution imaging phantom with sub-mm features. Methods: CT and PET scans of a 3D printed phantom and a commercial Micro Deluxe (Data Spectrum Corporation, USA) phantom with 1.2, 1.6, 2.4, 3.2, 4.0, and 4.8 mm diameter hot rods were acquired. The measured PET and CT rod sizes, activities, and attenuation coefficients were compared. A PET/MRI scan of a custom 3D printed phantom with hot and cold rods was performed, with photon attenuation and normalization measurements performed with a separate 3D printed normalization phantom. X-ray transmission scans of a customized two level high resolution 3D printed phantom with sub-mm features were also performed. Results: Results show very good agreement between commercial and 3D printed micro deluxe phantoms with less than 3% difference in CT measured rod diameter, less than 5% difference in PET measured rod diameter, and a maximum of 6.2% difference in average rod activity from a 10 min, 333 kBq/ml (9 μCi/ml) Siemens Inveon (Siemens Healthcare, Germany) PET scan. In all cases, these differences were within the measurement uncertainties of our setups. PET/MRI scans successfully identified 3D printed hot and cold rods on PET and MRI modalities. X-ray projection images of a 3D printed high resolution phantom identified features as small as 350 μm wide. Conclusions: This work shows that 3D printed

  18. Technical Note: Characterization of custom 3D printed multimodality imaging phantoms.

    Science.gov (United States)

    Bieniosek, Matthew F; Lee, Brian J; Levin, Craig S

    2015-10-01

    Imaging phantoms are important tools for researchers and technicians, but they can be costly and difficult to customize. Three dimensional (3D) printing is a widely available rapid prototyping technique that enables the fabrication of objects with 3D computer generated geometries. It is ideal for quickly producing customized, low cost, multimodal, reusable imaging phantoms. This work validates the use of 3D printed phantoms by comparing CT and PET scans of a 3D printed phantom and a commercial "Micro Deluxe" phantom. This report also presents results from a customized 3D printed PET/MRI phantom, and a customized high resolution imaging phantom with sub-mm features. CT and PET scans of a 3D printed phantom and a commercial Micro Deluxe (Data Spectrum Corporation, USA) phantom with 1.2, 1.6, 2.4, 3.2, 4.0, and 4.8 mm diameter hot rods were acquired. The measured PET and CT rod sizes, activities, and attenuation coefficients were compared. A PET/MRI scan of a custom 3D printed phantom with hot and cold rods was performed, with photon attenuation and normalization measurements performed with a separate 3D printed normalization phantom. X-ray transmission scans of a customized two level high resolution 3D printed phantom with sub-mm features were also performed. Results show very good agreement between commercial and 3D printed micro deluxe phantoms with less than 3% difference in CT measured rod diameter, less than 5% difference in PET measured rod diameter, and a maximum of 6.2% difference in average rod activity from a 10 min, 333 kBq/ml (9 μCi/ml) Siemens Inveon (Siemens Healthcare, Germany) PET scan. In all cases, these differences were within the measurement uncertainties of our setups. PET/MRI scans successfully identified 3D printed hot and cold rods on PET and MRI modalities. X-ray projection images of a 3D printed high resolution phantom identified features as small as 350 μm wide. This work shows that 3D printed phantoms can be functionally equivalent to

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

    Science.gov (United States)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Choonsik [Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, FL 32611 (United States); Lodwick, Daniel [Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, FL 32611 (United States); Hasenauer, Deanna [Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, FL 32611 (United States); Williams, Jonathan L [Department of Radiology, University of Florida, Gainesville, FL 32611 (United States); Lee, Choonik [MD Anderson Cancer Center-Orlando, Orlando, FL 32806 (United States); Bolch, Wesley E [Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, FL 32611 (United States)

    2007-07-21

    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

  1. Testing gravity of a regular and slowly rotating phantom black hole by quasi-periodic oscillations

    CERN Document Server

    Chen, Songbai; Jing, Jiliang

    2016-01-01

    We extend firstly the regular phantom black hole solution to a slowly rotating black hole case and find that the phantom field depresses the angular velocity of the event horizon and suppresses the super-radiation of black hole. We also probe the dependence of quasi-periodic oscillations frequencies in relativistic precession model on the phantom parameter. With the observation data of GRO J1655-40, we make a constraint on the parameters of the regular and slowly rotating phantom black hole. Our results show that although the best-fit value of the phantom parameter $b$ is small, the allowed value of $b$ in the $1\\sigma$ region is $b<0.619$, which means that the phantom theoretical model can not be excluded by the constraint from quasi-periodic oscillations with the observation data of GRO J1655-40.

  2. Quantification of breast density using dual-energy mammography with liquid phantom calibration.

    Science.gov (United States)

    Lam, Alfonso R; Ding, Huanjun; Molloi, Sabee

    2014-07-21

    Breast density is a widely recognized potential risk factor for breast cancer. However, accurate quantification of breast density is a challenging task in mammography. The current use of plastic breast-equivalent phantoms for calibration provides limited accuracy in dual-energy mammography due to the chemical composition of the phantom. We implemented a breast-equivalent liquid phantom for dual-energy calibration in order to improve the accuracy of breast density measurement. To design these phantoms, three liquid compounds were chosen: water, isopropyl alcohol, and glycerol. Chemical compositions of glandular and adipose tissues, obtained from NIST database, were used as reference materials. Dual-energy signal of the liquid phantom at different breast densities (0% to 100%) and thicknesses (1 to 8 cm) were simulated. Glandular and adipose tissue thicknesses were estimated from a higher order polynomial of the signals. Our results indicated that the linear attenuation coefficients of the breast-equivalent liquid phantoms match those of the target material. Comparison between measured and known breast density data shows a linear correlation with a slope close to 1 and a non-zero intercept of 7%, while plastic phantoms showed a slope of 0.6 and a non-zero intercept of 8%. Breast density results derived from the liquid calibration phantoms showed higher accuracy than those derived from the plastic phantoms for different breast thicknesses and various tube voltages. We performed experimental phantom studies using liquid phantoms and then compared the computed breast density with those obtained using a bovine tissue model. The experimental data and the known values were in good correlation with a slope close to 1 (∼1.1). In conclusion, our results indicate that liquid phantoms are a reliable alternative for calibration in dual-energy mammography and better reproduce the chemical properties of the target material.

  3. Phantom limb perception interferes with motor imagery after unilateral upper-limb amputation.

    Science.gov (United States)

    Lyu, Yuanyuan; Guo, Xiaoli; Bekrater-Bodmann, Robin; Flor, Herta; Tong, Shanbao

    2016-02-16

    A potential contributor to impaired motor imagery in amputees is an alteration of the body schema as a result of the presence of a phantom limb. However, the nature of the relationship between motor imagery and phantom experiences remains unknown. In this study, the influence of phantom limb perception on motor imagery was investigated using a hand mental rotation task by means of behavioral and electrophysiological measures. Compared with healthy controls, significantly prolonged response time for both the intact and missing hand were observed specifically in amputees who perceived a phantom limb during the task but not in amputees without phantom limb perception. Event-related desynchronization of EEG in the beta band (beta-ERD) in central and parietal areas showed an angular disparity specifically in amputees with phantom limb perception, with its source localized in the right inferior parietal lobule. The response time as well as the beta-ERD values were significantly positively correlated with phantom vividness. Our results suggest that phantom limb perception during the task is an important interferential factor for motor imagery after amputation and the interference might be related to a change of the body representation resulting from an unnatural posture of the phantom limb.

  4. Phantom pain in bilateral upper limb amputation.

    Science.gov (United States)

    Modirian, Ehsan; Shojaei, Hadi; Soroush, Mohammad Reza; Masoumi, Mahdi

    2009-01-01

    To alert health professionals on presence and extent of phantom pain and sensation following bilateral upper limb amputation. Of a total of 140 war-related bilateral upper limb amputees in Iran, 103 subjects were thoroughly examined in this cross-sectional study by a physical medicine specialist. The patients were questioned for the presence of phantom pain and sensations, and frequency and intensity of the feeling were recorded. At 17.1 +/- 6.1 years after injury, 82.0% of the 103 amputees suffered from phantom sensation, including varying degrees of phantom limb pain in 53.9% of stumps. Phantom phenomena had a higher frequency in the right extremities, but this was not statistically significant (p > 0.01). Of those amputees who had phantom pain or sensation, 51.2% reported that they 'always' had phantom limb sensation; and approximately one-fourth of the subjects (24.6%) 'always' had phantom pain. Among the stumps who reported phantom pain (N=112), the pain was excruciating (38.5%), distressing (34.9%) or discomforting (25.6%). A significant statistical relation between phantom limb sensation and level of amputation was observed (p phantom pain; medical and surgical modalities only bring temporary relief, and less than 1% of the respondents achieve permanent relief through different treatment methods.

  5. CREATION OF FEMALE COMPUTATIONAL PHANTOMS FOR CALIBRATION OF LUNG COUNTERS.

    Science.gov (United States)

    Lombardo, Pasquale Alessandro; Lebacq, Anne Laure; Vanhavere, Filip

    2016-09-01

    Plutonium isotopes are of high concern because they lead to high doses. In case of contamination, the activity burden inside the lungs should be assessed accurately. Many studies showed that the presence of breasts has a substantial influence on lung counting efficiencies. Currently, the calibration of most lung counting systems is done by means of physical phantoms representing only male chests. A set of female computational phantoms has been developed in order to provide gender-specific efficiency calibrations for the (241)Am gamma emission (59.54 keV). The phantoms were created starting from a library of female chest phantoms provided by Institut de radioprotection et de sûreté nucléaire (IRSN) (Farah, J. Amélioration des mesures anthroporadiamétriques personnalisées assistées par calcul Monte Carlo: optimisation des temps de calculs et méthodologie de mesure pour l'établissement de la répartition d'activite. PhD Thesis, 2011). While the IRSN phantoms represent a supine measurement position, the SCK•CEN lung counter set-up requires the persons to be sitting in a chair. Using open-source software, the breast shapes of the original phantoms have been recreated to simulate the drooping of breasts in vertical sitting position. A Monte Carlo approach was chosen for calculating calibration coefficients for female lung counting. The results obtained with MCNPx 2.7 simulations showed a significant decrease in the detection efficiency. For bigger bust and breast sizes, the detection efficiency showed to be up to 10 times lower than the ones measured with the Livermore male torso phantom. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. Fuzzy classification of phantom parent groups in an animal model

    Directory of Open Access Journals (Sweden)

    Fikse Freddy

    2009-09-01

    Full Text Available Abstract Background Genetic evaluation models often include genetic groups to account for unequal genetic level of animals with unknown parentage. The definition of phantom parent groups usually includes a time component (e.g. years. Combining several time periods to ensure sufficiently large groups may create problems since all phantom parents in a group are considered contemporaries. Methods To avoid the downside of such distinct classification, a fuzzy logic approach is suggested. A phantom parent can be assigned to several genetic groups, with proportions between zero and one that sum to one. Rules were presented for assigning coefficients to the inverse of the relationship matrix for fuzzy-classified genetic groups. This approach was illustrated with simulated data from ten generations of mass selection. Observations and pedigree records were randomly deleted. Phantom parent groups were defined on the basis of gender and generation number. In one scenario, uncertainty about generation of birth was simulated for some animals with unknown parents. In the distinct classification, one of the two possible generations of birth was randomly chosen to assign phantom parents to genetic groups for animals with simulated uncertainty, whereas the phantom parents were assigned to both possible genetic groups in the fuzzy classification. Results The empirical prediction error variance (PEV was somewhat lower for fuzzy-classified genetic groups. The ranking of animals with unknown parents was more correct and less variable across replicates in comparison with distinct genetic groups. In another scenario, each phantom parent was assigned to three groups, one pertaining to its gender, and two pertaining to the first and last generation, with proportion depending on the (true generation of birth. Due to the lower number of groups, the empirical PEV of breeding values was smaller when genetic groups were fuzzy-classified. Conclusion Fuzzy

  7. Phantom positioning variation in the Gamma Knife® Perfexion dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Nathalia Almeida; Potiens, Maria da Penha Albuquerque [Instituto de Pesquisas Energeticas e Nucleres (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Saraiva, Crystian [Hospital do Coracao, Sao Paulo, SP (Brazil)

    2015-07-01

    The use of small volume ionization chamber has become required for the dosimetry of equipment that use small radiation fields. A pinpoint ionization chamber is ideal for the dosimetry of a Gamma Knife® Perfexion (GKP) unit. In this work, this chamber was inserted into the phantom, and measurements were performed with the phantom in different positions, in order to verify if the change in the phantom positioning affects the dosimetry of the GKP. Three different phantom positions were performed. The variation in the result is within the range allowed for the dosimetry of a GKP equipment. (author)

  8. Induced sensorimotor brain plasticity controls pain in phantom limb patients

    Science.gov (United States)

    Yanagisawa, Takufumi; Fukuma, Ryohei; Seymour, Ben; Hosomi, Koichi; Kishima, Haruhiko; Shimizu, Takeshi; Yokoi, Hiroshi; Hirata, Masayuki; Yoshimine, Toshiki; Kamitani, Yukiyasu; Saitoh, Youichi

    2016-01-01

    The cause of pain in a phantom limb after partial or complete deafferentation is an important problem. A popular but increasingly controversial theory is that it results from maladaptive reorganization of the sensorimotor cortex, suggesting that experimental induction of further reorganization should affect the pain, especially if it results in functional restoration. Here we use a brain–machine interface (BMI) based on real-time magnetoencephalography signals to reconstruct affected hand movements with a robotic hand. BMI training induces significant plasticity in the sensorimotor cortex, manifested as improved discriminability of movement information and enhanced prosthetic control. Contrary to our expectation that functional restoration would reduce pain, the BMI training with the phantom hand intensifies the pain. In contrast, BMI training designed to dissociate the prosthetic and phantom hands actually reduces pain. These results reveal a functional relevance between sensorimotor cortical plasticity and pain, and may provide a novel treatment with BMI neurofeedback. PMID:27807349

  9. Induced sensorimotor brain plasticity controls pain in phantom limb patients.

    Science.gov (United States)

    Yanagisawa, Takufumi; Fukuma, Ryohei; Seymour, Ben; Hosomi, Koichi; Kishima, Haruhiko; Shimizu, Takeshi; Yokoi, Hiroshi; Hirata, Masayuki; Yoshimine, Toshiki; Kamitani, Yukiyasu; Saitoh, Youichi

    2016-10-27

    The cause of pain in a phantom limb after partial or complete deafferentation is an important problem. A popular but increasingly controversial theory is that it results from maladaptive reorganization of the sensorimotor cortex, suggesting that experimental induction of further reorganization should affect the pain, especially if it results in functional restoration. Here we use a brain-machine interface (BMI) based on real-time magnetoencephalography signals to reconstruct affected hand movements with a robotic hand. BMI training induces significant plasticity in the sensorimotor cortex, manifested as improved discriminability of movement information and enhanced prosthetic control. Contrary to our expectation that functional restoration would reduce pain, the BMI training with the phantom hand intensifies the pain. In contrast, BMI training designed to dissociate the prosthetic and phantom hands actually reduces pain. These results reveal a functional relevance between sensorimotor cortical plasticity and pain, and may provide a novel treatment with BMI neurofeedback.

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Zubal, I.G.; Harrell, C.R.; Smith, E.O.; Smith, A.L.; Krischlunas, P. [Yale Univ., New Haven, CT (United States). Dept. of Diagnostic Radiology

    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.

  12. Suicidal thoughts/acts and clinical correlates in patients with depressive disorders in Asians: results from the REAP-AD study.

    Science.gov (United States)

    Park, Seon-Cheol; Lee, Min-Soo; Hahn, Sang Woo; Si, Tian-Mei; Kanba, Shigenobu; Chong, Mian-Yoon; Yoon, Chee Kok; Udomratn, Pichet; Tripathi, Adarsh; Sartorius, Norman; Shinfuku, Naotaka; Maramis, Margarita M; Park, Yong Chon

    2016-12-01

    Using data from the Research on Asian Psychotropic Prescription Patterns for Antidepressants (REAP-AD) study, we aimed to present the rates and clinical correlates of suicidal thoughts/acts in patients recruited from a total of 40 centres in 10 Asian countries/areas: China, Hong Kong, India, Indonesia, Japan, Korea, Malaysia, Singapore, Taiwan, and Thailand. Data from 1122 patients with depressive disorders in the REAP-AD study were used. The ICD-10 was employed to diagnose depressive episodes and recurrent depressive disorder. The presence or absence of suicidal thoughts/acts and profile of other depressive symptoms was established using the National Institute for Health and Clinical Excellence guidelines for depression. Country/area differences in rates of suicidal thoughts/acts were evaluated with the χ2 test. In addition, depressive symptom profiles, other clinical characteristics, and patterns of psychotropic drug prescription in depressed patients with and without suicidal thoughts/acts were compared using analysis of covariance for continuous variables and logistic regression analysis for discrete variables to adjust the effects of covariates. The rates of suicidal thoughts/acts in 10 countries/areas varied from 12.8% in Japan to 36.3% in China. Patients with suicidal thoughts/acts presented more persistent sadness (adjusted odds ratio [aOR]=2.64, p<0.001), loss of interest (aOR=2.33, p<0.001), fatigue (aOR=1.58, p<0.001), insomnia (aOR=1.74, p<0.001), poor concentration (aOR=1.88, p<0.001), low self-confidence (aOR=1.78, p<0.001), poor appetite (aOR=2.27, p<0.001), guilt/self-blame (aOR=3.03, p<0.001), and use of mood stabilisers (aOR=1.79, p<0.001) than those without suicidal thoughts/acts. Suicidal thoughts/acts can indicate greater severity of depression, and are associated with a poorer response to antidepressants and increased burden of illness. Hence, suicidal thoughts/acts can provide a clinical index reflecting the clinical status of depressive

  13. Close relationships between Asian American and European American college students.

    Science.gov (United States)

    Chen, C; Edwards, K; Young, B; Greenberger, E

    2001-02-01

    The authors examined attitudes and behaviors regarding close relationships between European and Asian Americans, with a particular emphasis on 5 major subgroups of Asian Americans (Chinese, Japanese, Korean, Vietnamese, and Filipino Americans). Participants were 218 Asian American college students and 171 European American college students attending a culturally diverse university. The European Americans did not differentiate among the various subgroups of Asian Americans. Their attitudes regarding close relationships were less positive toward Asian Americans than toward Mexican and African Americans, a finding contrary to the prediction of social exchange theory (H. Tajfel, 1975). In contrast to the European Americans' view of homogeneity among Asian Americans, the 5 major subgroups of Asian Americans expressed a distinctive hierarchy of social preference among themselves. Results are discussed in terms of their implications for future research on interethnic relations involving Asian Americans.

  14. Phantom hand and wrist movements in upper limb amputees are slow but naturally controlled movements.

    Science.gov (United States)

    De Graaf, J B; Jarrassé, N; Nicol, C; Touillet, A; Coyle, T; Maynard, L; Martinet, N; Paysant, J

    2016-01-15

    After limb amputation, patients often wake up with a vivid perception of the presence of the missing limb, called "phantom limb". Phantom limbs have mostly been studied with respect to pain sensation. But patients can experience many other phantom sensations, including voluntary movements. The goal of the present study was to quantify phantom movement kinematics and relate these to intact limb kinematics and to the time elapsed since amputation. Six upper arm and two forearm amputees with various delays since amputation (6months to 32years) performed phantom finger, hand and wrist movements at self-chosen comfortable velocities. The kinematics of the phantom movements was indirectly obtained via the intact limb that synchronously mimicked the phantom limb movements, using a Cyberglove® for measuring finger movements and an inertial measurement unit for wrist movements. Results show that the execution of phantom movements is perceived as "natural" but effortful. The types of phantom movements that can be performed are variable between the patients but they could all perform thumb flexion/extension and global hand opening/closure. Finger extension movements appeared to be 24% faster than finger flexion movements. Neither the number of types of phantom movements that can be executed nor the kinematic characteristics were related to the elapsed time since amputation, highlighting the persistence of post-amputation neural adaptation. We hypothesize that the perceived slowness of phantom movements is related to altered proprioceptive feedback that cannot be recalibrated by lack of visual feedback during phantom movement execution. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  15. Is There a Healthy Immigrant Effect Among Women Through Transnational Marriage? Results from Immigrant Women from Southeast Asian Countries in Taiwan.

    Science.gov (United States)

    Huang, Sheng-Shiung; Yang, Hao-Jan

    2018-02-01

    In this study we examine whether there is healthy immigrant effect among women immigrated to Taiwan through transnational marriage. A sample of immigrant women (N = 246) with original nativity of Southeast Asian countries and Taiwanese-born women sample (N = 201) was recruited from December 2008 to December 2009. Their depressive symptoms, acculturative stresses and family functioning were assessed by a series of questionnaires. Immigrant women had lower depressive scores than their native-born counterparts when other potential confounders were controlled for in the multiple regression model. Our findings suggest that the healthy immigrant effect exists among immigrant women in Taiwan. Although such effect may due to immigrant women is a highly selective population with hardy mental characteristics, it is crucial to improve immigrant women's mental health by helping them to enhance the ability of expressing emotions between family members as well as by mitigating socioeconomic inequality of cross-cultural immigrant families.

  16. Solid tissue simulating phantoms having absorption at 970 nm for diffuse optics

    Science.gov (United States)

    Kennedy, Gordon T.; Lentsch, Griffin R.; Trieu, Brandon; Ponticorvo, Adrien; Saager, Rolf B.; Durkin, Anthony J.

    2017-07-01

    Tissue simulating phantoms can provide a valuable platform for quantitative evaluation of the performance of diffuse optical devices. While solid phantoms have been developed for applications related to characterizing exogenous fluorescence and intrinsic chromophores such as hemoglobin and melanin, we report the development of a poly(dimethylsiloxane) (PDMS) tissue phantom that mimics the spectral characteristics of tissue water. We have developed these phantoms to mimic different water fractions in tissue, with the purpose of testing new devices within the context of clinical applications such as burn wound triage. Compared to liquid phantoms, cured PDMS phantoms are easier to transport and use and have a longer usable life than gelatin-based phantoms. As silicone is hydrophobic, 9606 dye was used to mimic the optical absorption feature of water in the vicinity of 970 nm. Scattering properties are determined by adding titanium dioxide, which yields a wavelength-dependent scattering coefficient similar to that observed in tissue in the near-infrared. Phantom properties were characterized and validated using the techniques of inverse adding-doubling and spatial frequency domain imaging. Results presented here demonstrate that we can fabricate solid phantoms that can be used to simulate different water fractions.

  17. Quantitative bone mineral analysis using computed tomography with the new calibration phantom

    Energy Technology Data Exchange (ETDEWEB)

    Kakuta, Shigeru (Saint Marianna Univ. School of Medicine, Kawasaki, Kanagawa (Japan))

    1992-10-01

    There are several problems in quantitative bone mineral analysis using computed tomography. Recently, CaCO[sub 3] phantom (B-MAS) has been widely used to measure the bone mineral content, although B-MAS has two problems. Firstly, the characteristics of X-ray absorption of CaCO[sub 3] are different from those of hydroxyapatite which is the main component of bone tissue. Secondly, in small patients, the phantom does not fit the body well due to its large (300 mm) width. This discrepancy between patient and phantom leads to inexact CT-number measurement of the most lateral chambers on both sides. To solve these problems, a new calibration phantom containing known concentrations of hydroxyapatite (0, 50, 100, 150, 200 mm/cm[sup 3]) as a standard substance was developed, and the width of the phantom was reduced from 300 mm to 200 mm. Clinically, quantitative computed tomography (QCT) of the third lumbar vertebral body was performed with this new phantom in 178 cases and compared with those of the B-MAS phantom. The correlations between the concentration of the standard substance and CT-number were significantly higher in the new phantom than in the B-MAS. Based on these results, we consider the new calibration phantom useful for bone-mineral measurement by QCT. (author).

  18. Tissue-mimicking phantoms for photoacoustic and ultrasonic imaging

    Science.gov (United States)

    Cook, Jason R.; Bouchard, Richard R.; Emelianov, Stanislav Y.

    2011-01-01

    In both photoacoustic (PA) and ultrasonic (US) imaging, overall image quality is influenced by the optical and acoustical properties of the medium. Consequently, with the increased use of combined PA and US (PAUS) imaging in preclinical and clinical applications, the ability to provide phantoms that are capable of mimicking desired properties of soft tissues is critical. To this end, gelatin-based phantoms were constructed with various additives to provide realistic acoustic and optical properties. Forty-micron, spherical silica particles were used to induce acoustic scattering, Intralipid® 20% IV fat emulsion was employed to enhance optical scattering and ultrasonic attenuation, while India Ink, Direct Red 81, and Evans blue dyes were utilized to achieve optical absorption typical of soft tissues. The following parameters were then measured in each phantom formulation: speed of sound, acoustic attenuation (from 6 to 22 MHz), acoustic backscatter coefficient (from 6 to 22 MHz), optical absorption (from 400 nm to 1300 nm), and optical scattering (from 400 nm to 1300 nm). Results from these measurements were then compared to similar measurements, which are offered by the literature, for various soft tissue types. Based on these comparisons, it was shown that a reasonably accurate tissue-mimicking phantom could be constructed using a gelatin base with the aforementioned additives. Thus, it is possible to construct a phantom that mimics specific tissue acoustical and/or optical properties for the purpose of PAUS imaging studies. PMID:22076278

  19. Optimized generation of high resolution breast anthropomorphic software phantoms

    Science.gov (United States)

    Pokrajac, David D.; Maidment, Andrew D. A.; Bakic, Predrag R.

    2012-01-01

    Purpose: The authors present an efficient method for generating anthropomorphic software breast phantoms with high spatial resolution. Employing the same region growing principles as in their previous algorithm for breast anatomy simulation, the present method has been optimized for computational complexity to allow for fast generation of the large number of phantoms required in virtual clinical trials of breast imaging. Methods: The new breast anatomy simulation method performs a direct calculation of the Cooper’s ligaments (i.e., the borders between simulated adipose compartments). The calculation corresponds to quadratic decision boundaries of a maximum a posteriori classifier. The method is multiscale due to the use of octree-based recursive partitioning of the phantom volume. The method also provides user-control of the thickness of the simulated Cooper’s ligaments and skin. Results: Using the proposed method, the authors have generated phantoms with voxel size in the range of (25–1000 μm)3/voxel. The power regression of the simulation time as a function of the reciprocal voxel size yielded a log-log slope of 1.95 (compared to a slope of 4.53 of our previous region growing algorithm). Conclusions: A new algorithm for computer simulation of breast anatomy has been proposed that allows for fast generation of high resolution anthropomorphic software phantoms. PMID:22482649

  20. Radiological equipment analyzed by specific developed phantoms and software

    Energy Technology Data Exchange (ETDEWEB)

    Soto, M.; Campayo, J. M. [Logistica y Acondicionamientos Industriales SAU, Sorolla Center, Local 10, Av. de las Cortes Valencianas No. 58, 46015 Valencia (Spain); Mayo, P. [TITANIA Servicios Tecnologicos SL, Sorolla Center, Local 10, Av. de las Cortes Valencianas No. 58, 46015 Valencia (Spain); Verdu, G.; Rodenas, F., E-mail: m.soto@lainsa.co [ISIRYIM Universidad Politecnica de Valencia, Camino de Vera s/n, Valencia (Spain)

    2010-10-15

    The use of radiographic phantoms specifically designed to evaluate the operation of the radiographic equipment lets the study of the image quality obtained by this equipment in an objective way. In digital radiographic equipment, the analysis of the image quality can be computerized because the acquisition of the image is possible in different technologies that are, computerized radiography or phosphor plate and direct radiography or detector. In case of film-screen equipment s this analysis could be applied digitalising the image in a professional scanner. In this work we have shown an application to assess automatically the constancy quality image in the image chain of the radiographic equipment s. This application is integrated by designed radiographic phantoms which are adapted to conventional, dental equipment s and specific developed software for the automatic evaluation of the phantom image quality. The software is based on digital image processing techniques that let the automatic detection of the different phantom tests by edge detector, morphological operators, threshold histogram techniques... etc. The utility developed is enough sensitive to the radiographic equipment of operating conditions of voltage (kV) and charge (m As). It is a friendly user programme connected with a data base of the hospital or clinic where it has been used. After the phantom image processing the user can obtain an inform with a resume of the imaging system state with accepting and constancy results. (Author)

  1. Asian Black Carbon Influence on East Asian Summer Monsoons

    Science.gov (United States)

    Mahmood, R.; Li, S.

    2012-04-01

    Since the black carbon (BC) emission in East and South Asia has increased significantly during the last decades of the 20th century, there is an ever growing concern about its impact on Asian monsoon. In this study we provide an in-depth analysis of the influence by performing several ensemble sensitive experiments with or without historical BC concentrations over East Asia, South Asia, and the combined East and South Asia in an atmospheric general circulation model, GFDL AM2.1. The results show that: (a) The East Asian summer climate is sensitive to the East Asian BC (EABC) concentrations in a sense that EABC contributes significantly to the frequently occurring north-drought and south-flood patterns in Eastern China. In detail, the large scale precipitation anomalies induced by EABC characterize more rainfalls over central/south China, East China Sea and southern Japan and less rainfall over northern China and the west Pacific region between 10° to 20°N. These anomalous precipitation patterns are mainly attributed to the EABC induced large scale circulation changes including the weakened Western Pacific Subtropical High (WPSH), anomalous ascent motions over central-southern China (centering over the Yangtze River valley (YRV)) and the subsequent descent motions over northern China and the South China Sea. These modeled results suggest that the EABC experiment reproduces the climate shift event of eastern China during the late 1970s, including intensified rainfall in the YRV and the weakened summer monsoonal circulation. (b) The anomalous results of South Asian BC (SABC) experiment signify a tri-polar precipitation response over East Asia, with a reduction from the YRV to East China Sea and southern Japan sandwiched with increases over a northern domain from northern China/ Korea to northern Japan and over southern China. As for southern China, particularly the YRV, the impact of SABC is to offset a fraction of intensified rainfall induced by local BC of East

  2. Three-dimensional printing of tissue phantoms for biophotonic imaging.

    Science.gov (United States)

    Wang, Jianting; Coburn, James; Liang, Chia-Pin; Woolsey, Nicholas; Ramella-Roman, Jessica C; Chen, Yu; Pfefer, T Joshua

    2014-05-15

    We have investigated the potential of tissue phantoms fabricated with thermosoftening- and photopolymerization-based three-dimensional (3D) printers for use in evaluation of biophotonic imaging systems. The optical properties of printed polymer samples were measured and compared to biological tissues. Phantoms with subsurface channels as small as 0.2 mm in diameter were fabricated and imaged with microscopy, x-ray microtomography, and optical coherence tomography to characterize morphology. These phantoms were then implemented to evaluate the penetration depth of a hyperspectral reflectance imaging system used in conjunction with a near-infrared contrast agent. Results indicated that 3D printing may provide a suitable platform for performance testing in biophotonics, although subsurface imaging is critical to mitigate printer-to-printer variability in matrix homogeneity and feature microstructure.

  3. Osteoporosis and Asian American Women

    Science.gov (United States)

    ... Breadcrumb Home Osteoporosis Osteoporosis and Asian American Women Osteoporosis and Asian American Women Asian American women are ... Are Available? Resources For Your Information What Is Osteoporosis? Osteoporosis is a condition in which the bones ...

  4. Dual Energy Tomosynthesis breast phantom imaging

    Science.gov (United States)

    Koukou, V.; Martini, N.; Fountos, G.; Messaris, G.; Michail, C.; Kandarakis, I.; Nikiforidis, G.

    2017-12-01

    Dual energy (DE) imaging technique has been applied to many theoretical and experimental studies. The aim of the current study is to evaluate dual energy in breast tomosynthesis using commercial tomosynthesis system in terms of its potential to better visualize microcalcifications (μCs). The system uses a tungsten target X-ray tube and a selenium direct conversion detector. Low-energy (LE) images were acquired at different tube voltages (28, 30, 32 kV), while high-energy images at 49 kV. Fifteen projections, for the low- and high-energy respectively, were acquired without grid while tube scanned continuously. Log-subtraction algorithm was used in order to obtain the DE images with the weighting factor, w, derived empirically. The subtraction was applied to each pair of LE and HE slices after reconstruction. The TORMAM phantom was imaged with the different settings. Four regions-of-interest including μCs were identified in the inhomogeneous part of the phantom. The μCs in DE images were more clearly visible compared to the low-energy images. Initial results showed that DE tomosynthesis imaging is a promising modality, however more work is required.

  5. Phantom black holes and critical phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Azreg-Aïnou, Mustapha [Engineering Faculty, Başkent University, Bağlıca Campus, Ankara (Turkey); Marques, Glauber T. [Universidade Federal Rural da Amazônia ICIBE-LASIC, Av. Presidente Tancredo Neves 2501, CEP 66077-901—Belém/PA (Brazil); Rodrigues, Manuel E., E-mail: azreg@baskent.edu.tr, E-mail: gtadaiesky@hotmail.com, E-mail: esialg@gmail.com [Faculdade de Ciências Exatas e Tecnologia, Universidade Federal do Pará, Campus Universitário de Abaetetuba, CEP 68440-000, Abaetetuba, Pará (Brazil)

    2014-07-01

    We consider the two classes cosh and sinh of normal and phantom black holes of Einstein-Maxwell-dilaton theory. The thermodynamics of these holes is characterized by heat capacities that may have both signs depending on the parameters of the theory. Leaving aside the normal Reissner-Nordström black hole, it is shown that only some phantom black holes of both classes exhibit critical phenomena. The two classes share a nonextremality, but special, critical point where the transition is continuous and the heat capacity, at constant charge, changes sign with an infinite discontinuity. This point yields a classification scheme for critical points. It is concluded that the two unstable and stable phases coexist on one side of the criticality state and disappear on the other side, that is, there is no configuration where only one phase exists. The sinh class has an extremality critical point where the entropy diverges. The transition from extremality to nonextremality with the charge held constant is accompanied by a loss of mass and an increase in the temperature. A special case of this transition is when the hole is isolated (microcanonical ensemble), it will evolve by emission of energy, which results in a decrease of its mass, to the final state of minimum mass and vanishing heat capacity. The Ehrenfest scheme of classification is inaccurate in this case but the generalized one due to Hilfer leads to conclude that the transition is of order less than unity. Fluctuations near criticality are also investigated.

  6. Genetics of Tinnitus: Time to Biobank Phantom Sounds

    Directory of Open Access Journals (Sweden)

    Christopher R. Cederroth

    2017-09-01

    Full Text Available Tinnitus is a common phantom sensation resulting most often from sensory deprivation, and for which little knowledge on the molecular mechanisms exists. While the existing evidence for a genetic influence on the condition has been until now sparse and underpowered, recent data suggest that specific forms of tinnitus have a strong genetic component revealing that not all tinnitus percepts are alike, at least in how they are genetically driven. These new findings pave the way for a better understanding on how phantom sensations are molecularly driven and call for international biobanking efforts.

  7. Neutron dosimetry in solid water phantom

    Energy Technology Data Exchange (ETDEWEB)

    Benites-Rengifo, Jorge Luis, E-mail: jlbenitesr@prodigy.net.mx [Centro Estatal de Cancerologia de Nayarit, Calzada de la Cruz 118 Sur, Tepic Nayarit, Mexico and Instituto Tecnico Superior de Radiologia, ITEC, Calle Leon 129, Tepic Nayarit (Mexico); Vega-Carrillo, Hector Rene, E-mail: fermineutron@yahoo.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Apdo. postal 336, 98000, Zacatecas, Zac. (Mexico)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    Yeom, Yeon Soo; Wang, Zhao Jun; Nguyen, Thang Tat; 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

    2016-10-07

    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.

  10. Motor correlates of phantom limb pain.

    Science.gov (United States)

    Kikkert, Sanne; Mezue, Melvin; Henderson Slater, David; Johansen-Berg, Heidi; Tracey, Irene; Makin, Tamar R

    2017-10-01

    Following amputation, individuals ubiquitously report experiencing lingering sensations of their missing limb. While phantom sensations can be innocuous, they are often manifested as painful. Phantom limb pain (PLP) is notorious for being difficult to monitor and treat. A major challenge in PLP management is the difficulty in assessing PLP symptoms, given the physical absence of the affected body part. Here, we offer a means of quantifying chronic PLP by harnessing the known ability of amputees to voluntarily move their phantom limbs. Upper-limb amputees suffering from chronic PLP performed a simple finger-tapping task with their phantom hand. We confirm that amputees suffering from worse chronic PLP had worse motor control over their phantom hand. We further demonstrate that task performance was consistent over weeks and did not relate to transient PLP or non-painful phantom sensations. Finally, we explore the neural basis of these behavioural correlates of PLP. Using neuroimaging, we reveal that slower phantom hand movements were coupled with stronger activity in the primary sensorimotor phantom hand cortex, previously shown to associate with chronic PLP. By demonstrating a specific link between phantom hand motor control and chronic PLP, our findings open up new avenues for PLP management and improvement of existing PLP treatments. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  11. Emerging Asian Economics.

    Science.gov (United States)

    Trezise, Philip H.

    What we can expect in the future from the miracle economies of Japan, South Korea, Taiwan, Singapore, and Hong Kong, whether they pose a threat to the older industrial states of Western Europe and North American, and whether China is to be the next emerging Asian economy are discussed. The amazing economic recovery of these East Asian countries…

  12. Phantom pain and risk factors : A multivariate analysis

    NARCIS (Netherlands)

    Dijkstra, PU; Geertzen, JHB; Stewart, R; van der Schans, CP

    2002-01-01

    Phantom pain has been given considerable attention in literature. Phantom Pain reduces quality of life, and patients suffering from phantom pain make heavy use of the medical system. Many risk factors have been identified for phantom Pain in univariate analyses, including phantom sensations, stump

  13. Design and development of an ultrasound calibration phantom and system

    Science.gov (United States)

    Cheng, Alexis; Ackerman, Martin K.; Chirikjian, Gregory S.; Boctor, Emad M.

    2014-03-01

    Image-guided surgery systems are often used to provide surgeons with informational support. Due to several unique advantages such as ease of use, real-time image acquisition, and no ionizing radiation, ultrasound is a common medical imaging modality used in image-guided surgery systems. To perform advanced forms of guidance with ultrasound, such as virtual image overlays or automated robotic actuation, an ultrasound calibration process must be performed. This process recovers the rigid body transformation between a tracked marker attached to the ultrasound transducer and the ultrasound image. A phantom or model with known geometry is also required. In this work, we design and test an ultrasound calibration phantom and software. The two main considerations in this work are utilizing our knowledge of ultrasound physics to design the phantom and delivering an easy to use calibration process to the user. We explore the use of a three-dimensional printer to create the phantom in its entirety without need for user assembly. We have also developed software to automatically segment the three-dimensional printed rods from the ultrasound image by leveraging knowledge about the shape and scale of the phantom. In this work, we present preliminary results from using this phantom to perform ultrasound calibration. To test the efficacy of our method, we match the projection of the points segmented from the image to the known model and calculate a sum squared difference between each point for several combinations of motion generation and filtering methods. The best performing combination of motion and filtering techniques had an error of 1.56 mm and a standard deviation of 1.02 mm.

  14. Realistic deformable 3D numeric phantom for transcutaneous ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, Fernando Mitsuyama; Moraes, Matheus Cardoso; Furuie, Sergio Shiguemi, E-mail: fernando.okara@gmail.com [Universidade de Sao Paulo (USP), SP (Brazil). Escola de Engenharia

    2017-01-15

    Introduction: Numerical phantoms are important tools to design, calibrate and evaluate several methods in various image-processing applications, such as echocardiography and mammography. We present a framework for creating ultrasound numerical deformable phantoms based on Finite Element Method (FEM), Linear Isomorphism and Field II. The proposed method considers that the scatterers map is a property of the tissue; therefore, the scatterers should move according to the tissue strain. Methods: First, a volume representing the target tissue is loaded. Second, parameter values, such as Young's Modulus, scatterers density, attenuation and scattering amplitudes are inserted for each different regions of the phantom. Then, other parameters related to the ultrasound equipment, such as ultrasound frequency and number of transducer elements, are also defined in order to perform the ultrasound acquisition using Field II. Third, the size and position of the transducer and the pressures that are applied against the tissue are defined. Subsequently, FEM is executed and deformation is computed. Next, 3D linear isomorphism is performed to displace the scatterers according to the deformation. Finally, Field II is carried out to generate the non-deformed and deformed ultrasound data. Results: The framework is evaluated by comparing strain values obtained the numerical simulation and from the physical phantom from CIRS. The mean difference between both phantoms is lesser than 10%. Conclusion: The acoustic and deformation outcomes are similar to those obtained using a physical phantom. This framework led to a tool, which is available online and free of charges for educational and research purposes. (author)

  15. Polyvinyl chloride plastisol breast phantoms for ultrasound imaging.

    Science.gov (United States)

    de Carvalho, Isabela Miller; De Matheo, Lucas Lobianco; Costa Júnior, José Francisco Silva; Borba, Cecília de Melo; von Krüger, Marco Antonio; Infantosi, Antonio Fernando Catelli; Pereira, Wagner Coelho de Albuquerque

    2016-08-01

    Ultrasonic phantoms are objects that mimic some features of biological tissues, allowing the study of their interactions with ultrasound (US). In the diagnostic-imaging field, breast phantoms are an important tool for testing performance and optimizing US systems, as well as for training medical professionals. This paper describes the design and manufacture of breast lesions by using polyvinyl chloride plastisol (PVCP) as the base material. Among the materials available for this study, PVCP was shown to be stable, durable, and easy to handle. Furthermore, it is a nontoxic, nonpolluting, and low-cost material. The breast's glandular tissue (image background) was simulated by adding graphite powder with a concentration of 1% to the base material. Mixing PVCP and graphite powder in differing concentrations allows one to simulate lesions with different echogenicity patterns (anechoic, hypoechoic, and hyperechoic). From this mixture, phantom materials were obtained with speed of sound varying from 1379.3 to 1397.9ms(-1) and an attenuation coefficient having values between 0.29 and 0.94dBcm(-1) for a frequency of 1MHz at 24°C. A single layer of carnauba wax was added to the lesion surface in order to evaluate its applicability for imaging. The images of the phantoms were acquired using commercial ultrasound equipment; a specialist rated the images, elaborating diagnoses representative of both benign and malignant lesions. The results indicated that it was possible to easily create a phantom by using low-cost materials, readily available in the market and stable at room temperature, as the basis of ultrasonic phantoms that reproduce the image characteristics of fatty breast tissue and typical lesions of the breast. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Psychophysical Evaluation of the Capability for Phantom Limb Movement in Forearm Amputees.

    Science.gov (United States)

    Kawashima, Noritaka; Mita, Tomoki

    2016-01-01

    A phantom limb is the sensation that an amputated limb is still attached to the body and is moving together with other body parts. Phantom limb phenomenon is often described on the basis of the patient's subjective sense, for example as represented using a visual analog scale (VAS). The aim of this study was to propose a novel quantification method for behavioral aspect of phantom limb by psychophysics. Twelve unilateral forearm amputees were asked to perform phantom wrist motion with various motion frequencies (60, 80, 100, 120, 140, 160, 180, 200, 220, 240% of preferred speed). The attainment of phantom limb motion in each session was rated by the VAS ranging from 0 (hard) to 10 (easy). The relationship between the VAS and motion frequency was mathematically fitted by quadric function, and the value of shift and the degree of steepness were obtained as evaluation variables for the phantom limb movement. In order to test whether the proposed method can reasonably quantify the characteristics of phantom limb motion, we compared the variables among three different phantom limb movement conditions: (1) unilateral (phantom only), (2) bimanual, and (3) bimanual wrist movement with mirror reflection-induced visual feedback (MVF). While VAS rating showed a larger extent of inter- and intra-subject variability, the relationship of the VAS in response to motion frequency could be fitted by quadric curve, and the obtained parameters based on quadric function well characterize task-dependent changes in phantom limb movement. The present results suggest the potential usefulness of psychophysical evaluation as a validate assessment tool of phantom limb condition.

  17. Psychophysical Evaluation of the Capability for Phantom Limb Movement in Forearm Amputees.

    Directory of Open Access Journals (Sweden)

    Noritaka Kawashima

    Full Text Available A phantom limb is the sensation that an amputated limb is still attached to the body and is moving together with other body parts. Phantom limb phenomenon is often described on the basis of the patient's subjective sense, for example as represented using a visual analog scale (VAS. The aim of this study was to propose a novel quantification method for behavioral aspect of phantom limb by psychophysics. Twelve unilateral forearm amputees were asked to perform phantom wrist motion with various motion frequencies (60, 80, 100, 120, 140, 160, 180, 200, 220, 240% of preferred speed. The attainment of phantom limb motion in each session was rated by the VAS ranging from 0 (hard to 10 (easy. The relationship between the VAS and motion frequency was mathematically fitted by quadric function, and the value of shift and the degree of steepness were obtained as evaluation variables for the phantom limb movement. In order to test whether the proposed method can reasonably quantify the characteristics of phantom limb motion, we compared the variables among three different phantom limb movement conditions: (1 unilateral (phantom only, (2 bimanual, and (3 bimanual wrist movement with mirror reflection-induced visual feedback (MVF. While VAS rating showed a larger extent of inter- and intra-subject variability, the relationship of the VAS in response to motion frequency could be fitted by quadric curve, and the obtained parameters based on quadric function well characterize task-dependent changes in phantom limb movement. The present results suggest the potential usefulness of psychophysical evaluation as a validate assessment tool of phantom limb condition.

  18. Phantom pain and phantom sensations in upper limb amputees : an epidemiological study

    NARCIS (Netherlands)

    Kooijman, CM; Dijkstra, PU; Geertzen, JHB; Elzinga, A; van der Schans, CP

    Phantom pain in subjects with an amputated limb is a well-known problem. However, estimates of the prevalence of phantom pain differ considerably in the literature. Various factors associated with phantom pain have been described including pain before the amputation, gender, dominance, and time

  19. Development of PIMAL: Mathematical Phantom with Moving Arms and Legs

    Energy Technology Data Exchange (ETDEWEB)

    Akkurt, Hatice [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Eckerman, Keith F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2007-05-01

    The computational model of the human anatomy (phantom) has gone through many revisions since its initial development in the 1970s. The computational phantom model currently used by the Nuclear Regulatory Commission (NRC) is based on a model published in 1974. Hence, the phantom model used by the NRC staff was missing some organs (e.g., neck, esophagus) and tissues. Further, locations of some organs were inappropriate (e.g., thyroid).Moreover, all the computational phantoms were assumed to be in the vertical-upright position. However, many occupational radiation exposures occur with the worker in other positions. In the first phase of this work, updates on the computational phantom models were reviewed and a revised phantom model, which includes the updates for the relevant organs and compositions, was identified. This revised model was adopted as the starting point for this development work, and hence a series of radiation transport computations, using the Monte Carlo code MCNP5, was performed. The computational results were compared against values reported by the International Commission on Radiation Protection (ICRP) in Publication 74. For some of the organs (e.g., thyroid), there were discrepancies between the computed values and the results reported in ICRP-74. The reasons behind these discrepancies have been investigated and are discussed in this report.Additionally, sensitivity computations were performed to determine the sensitivity of the organ doses for certain parameters, including composition and cross sections used in the simulations. To assess the dose for more realistic exposure configurations, the phantom model was revised to enable flexible positioning of the arms and legs. Furthermore, to reduce the user time for analyses, a graphical user interface (GUI) was developed. The GUI can be used to visualize the positioning of the arms and legs as desired posture is achieved to generate the input file, invoke the computations, and extract the organ dose

  20. Do you believe in phantoms?

    CERN Multimedia

    Rosaria Marraffino

    2015-01-01

    “Phantoms” are tools that simulate a therapy’s response by mimicking the conditions of the human body. They are required in hadron therapy in order to optimise and verify the therapy before performing it on the patient. The better the phantom, the more accurate the treatment plan and the more effective the therapy. In the framework of the EU-funded project ENTERVISION*, a team of CERN researchers has designed an innovative piece of equipment able to evaluate radiobiology-related parameters in a very accurate way.   The ENTERVISION phantom being tested at HIT. A key challenge in hadron therapy – i.e. the medical use of hadrons to treat cancer – is to evaluate the biological effect of the delivered radiation. This can be achieved by using accurate dosimetry techniques to study the biological response in terms of the dose deposited and other physical parameters of the beam, such as the Linear Energy Transfer (LET). The job of the “phan...

  1. The phantom limb in dreams.

    Science.gov (United States)

    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.

  2. Comparative attenuation spectra of liquid skin-like phantoms

    CSIR Research Space (South Africa)

    Singh, A

    2010-09-01

    Full Text Available This study aims to extract and compare attenuation coefficients of different liquid skin-like phantoms representing Skin Types 1 to V1 with two methods, Spectrophotometric and Integrating Sphere methods. The correlation between the results of the 2...

  3. Comparison of methods for individualized astronaut organ dosimetry: Morphometry-based phantom library versus body contour autoscaling of a reference phantom

    Science.gov (United States)

    Sands, Michelle M.; Borrego, David; Maynard, Matthew R.; Bahadori, Amir A.; Bolch, Wesley E.

    2017-11-01

    One of the hazards faced by space crew members in low-Earth orbit or in deep space is exposure to ionizing radiation. It has been shown previously that while differences in organ-specific and whole-body risk estimates due to body size variations are small for highly-penetrating galactic cosmic rays, large differences in these quantities can result from exposure to shorter-range trapped proton or solar particle event radiations. For this reason, it is desirable to use morphometrically accurate computational phantoms representing each astronaut for a risk analysis, especially in the case of a solar particle event. An algorithm was developed to automatically sculpt and scale the UF adult male and adult female hybrid reference phantom to the individual outer body contour of a given astronaut. This process begins with the creation of a laser-measured polygon mesh model of the astronaut's body contour. Using the auto-scaling program and selecting several anatomical landmarks, the UF adult male or female phantom is adjusted to match the laser-measured outer body contour of the astronaut. A dosimetry comparison study was conducted to compare the organ dose accuracy of both the autoscaled phantom and that based upon a height-weight matched phantom from the UF/NCI Computational Phantom Library. Monte Carlo methods were used to simulate the environment of the August 1972 and February 1956 solar particle events. Using a series of individual-specific voxel phantoms as a local benchmark standard, autoscaled phantom organ dose estimates were shown to provide a 1% and 10% improvement in organ dose accuracy for a population of females and males, respectively, as compared to organ doses derived from height-weight matched phantoms from the UF/NCI Computational Phantom Library. In addition, this slight improvement in organ dose accuracy from the autoscaled phantoms is accompanied by reduced computer storage requirements and a more rapid method for individualized phantom generation

  4. CT images of an anthropomorphic and anthropometric male pelvis phantom

    Energy Technology Data Exchange (ETDEWEB)

    Matos, Andrea S.D. de; Campos, Tarcisio P.R. de, E-mail: campos@nuclear.ufmg.b [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Programa de Pos-graduacao em Ciencias e Tecnicas Nucleares

    2009-07-01

    Actually, among of the most often neoplasm types are the cancer of prostate, bladder and intestine. The incidence of the intestine neoplasm in Brazil is at fourth among the most frequent tumors of the male sex, barely close to the stomach, lung and prostate incidences. Phantoms are objects used as simulators for investigating ionizing radiation transport on humans, especially during radiation therapy or radiological diagnostic. The purpose of this work is the achievement of a set of computerized tomography (CT) images of a male pelvis phantom, with anthropomorphic and anthropometric features. It investigates and analyses the set of phantom CT images in according to a correspondent human pelvis one. The reason to develop a pelvis phantom is the needs of reproducing well established spatial dose distribution in radiation therapy, especially during calibration and protocol setup for various pelvis neoplasms. It aims to produce dose optimization on radiation therapy, improving health tissue protection and keeping control tumor dose. A male pelvis phantom with similar shape made of equivalent tissues was built for simulating the ionizing radiation transport to the human body. At the phantom, pelvis organs were reproduced including the bladder, the intestine, the prostate, the muscular and greasy tissue, as well as the bone tissue and the skin. A set of CT images was carried out in axial thin sections of 2mm thickness. As results, the constituent tissues had a tomography response on Hounsfield scale similar to values found on the human pelvis. Each tissue has its respective Hounsfield value, demonstrated here. The CT images also show that the organs have equivalent anthropometric measures and anthropomorphic features of the radiological human anatomy. The anatomical physical arrangement of the organs is also similar to of the pelvis human male, having the scales of gray and numerical scale of Hounsfield compatible with the scale of the human tissue. The phantom presents

  5. Sensitivity of Asian and African climate to variations in seasonal insolation, glacial ice cover, sea surface temperature, and Asian orography

    Science.gov (United States)

    Demenocal, Peter B.; Rind, David

    1993-01-01

    A general circulation model was used to investigate the sensitivity of Asian and African climate to prescribed changes in boundary conditions with the objective of identifying the relative importance of individual high-latitude glacial boundary conditions on seasonal climate and providing a physical basis for interpreting the paleoclimate record. The circulation model is described and results are presented. Insolation forcing increased summer Asian monsoon winds, while increased high-latitude ice cover strengthened winter Asian trade winds causing decreased precipitation. These factors had little effect on African climate. Cooler North Atlantic sea surface temperatures enhanced winter trade winds over North Africa, southern Asian climate was relatively unaffected. Reducing Asian orography enhanced Asian winter circulation while decreasing the summer monsoon. These model results suggest that African and southern Asian climate respond differently to separate elements of high-latitude climate variability.

  6. The neural basis of phantom limb pain.

    Science.gov (United States)

    Flor, Herta; Diers, Martin; Andoh, Jamila

    2013-07-01

    A recent study suggests that brain changes in amputees may be pain-induced, questioning maladaptive plasticity as a neural basis of phantom pain. These findings add valuable information on cortical reorganization after amputation. We suggest further lines of research to clarify the mechanisms that underlie phantom pain. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Resin phantoms as skin simulating layers

    CSIR Research Space (South Africa)

    Karsten, AE

    2011-07-01

    Full Text Available on the efficiency of Photodynamic Therapy (PDT) treatment. Two resin based solid phantoms were prepared to simulate two different skin types. Cells were prepared and PDT treatment were done on cells with and without the phantoms, by keeping the total dose delivered...

  8. Reorganization of motor and somatosensory cortex in upper extremity amputees with phantom limb pain.

    Science.gov (United States)

    Karl, A; Birbaumer, N; Lutzenberger, W; Cohen, L G; Flor, H

    2001-05-15

    Phantom limb pain (PLP) in amputees is associated with reorganizational changes in the somatosensory system. To investigate the relationship between somatosensory and motor reorganization and phantom limb pain, we used focal transcranial magnetic stimulation (TMS) of the motor cortex and neuroelectric source imaging of the somatosensory cortex (SI) in patients with and without phantom limb pain. For transcranial magnetic stimulation, recordings were made bilaterally from the biceps brachii, zygomaticus, and depressor labii inferioris muscles. Neuroelectric source imaging of the EEG was obtained after somatosensory stimulation of the skin overlying face and hand. Patients with phantom limb pain had larger motor-evoked potentials from the biceps brachii, and the map of outputs was larger for muscles on the amputated side compared with the intact side. The optimal scalp positions for stimulation of the zygomaticus and depressor labii inferioris muscles were displaced significantly more medially (toward the missing hand representation) in patients with phantom limb pain only. Neuroelectric source imaging revealed a similar medial displacement of the dipole center for face stimulation in patients with phantom limb pain. There was a high correlation between the magnitude of the shift of the cortical representation of the mouth into the hand area in motor and somatosensory cortex and phantom limb pain. These results show enhanced plasticity in both the motor and somatosensory domains in amputees with phantom limb pain.

  9. INFLUENCE OF DIFFERENT TYPES OF PHANTOMS ON THE CALIBRATION OF DOSEMETERS FOR EYE LENS DOSIMETRY.

    Science.gov (United States)

    Yoshitomi, H; Kowatari, M

    2016-09-01

    Both a cylinder and a slab phantom have been recommended to be used as calibration phantoms for eye lens dosimetry in the International Atomic Energy Agency TECDOC. This study describes investigations on the influence of the type of phantom on the calibration of dosemeters. In order to fulfil the purpose, backscatter radiation from practically used water-filled phantoms was evaluated by calculations and experiments. For photons, the calculations showed that the cylinder phantom had 10 % lower backscattered effect at maximum than a slab phantom, and simulated well the backscattered effect of the human head or neck to within ±10 %. The irradiation results of non-filtered optically stimulated luminescence and radio-photoluminescence glass dosemeters indicated that the differences of the calibration factors between the two types of phantoms were up to 20 and 10 %, respectively, reflecting the response to backscattered photons. For electrons, no difference was found between the two types of phantoms. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  10. Dosimetric comparison of tools for intensity modulated radiation therapy with gamma analysis: a phantom study

    Science.gov (United States)

    Akbas, Ugur; Okutan, Murat; Demir, Bayram; Koksal, Canan

    2015-07-01

    Dosimetry of the Intensity Modulated Radiation Therapy (IMRT) is very important because of the complex dose distributions. Diode arrays are the most common and practical measurement tools for clinical usage for IMRT. Phantom selection is critical for QA process. IMRT treatment plans are recalculated for the phantom irradiation in QA. Phantoms are made in different geometrical shapes to measure the doses of different types of irradiation techniques. Comparison of measured and calculated dose distributions for IMRT can be made by using gamma analysis. In this study, 10 head-and-neck IMRT QA plans were created with Varian Eclipse 8.9 treatment planning system. Water equivalent RW3-slab phantoms, Octavius-2 phantom and PTW Seven29 2D-array were used for QA measurements. Gantry, collimator and couch positions set to 00 and QA plans were delivered to RW3 and Octavius phantoms. Then the positions set to original angles and QA plans irradiated again. Measured and calculated fluence maps were evaluated with gamma analysis for different DD and DTA criteria. The effect of different set-up conditions for RW3 and Octavius phantoms in QA plan delivery evaluated by gamma analysis. Results of gamma analysis show that using RW3-slab phantoms with setting parameters to 00 is more appropriate for IMRT QA.

  11. Phantom motor execution facilitated by machine learning and augmented reality as treatment for phantom limb pain: a single group, clinical trial in patients with chronic intractable phantom limb pain.

    Science.gov (United States)

    Ortiz-Catalan, Max; Guðmundsdóttir, Rannveig A; Kristoffersen, Morten B; Zepeda-Echavarria, Alejandra; Caine-Winterberger, Kerstin; Kulbacka-Ortiz, Katarzyna; Widehammar, Cathrine; Eriksson, Karin; Stockselius, Anita; Ragnö, Christina; Pihlar, Zdenka; Burger, Helena; Hermansson, Liselotte

    2016-12-10

    Phantom limb pain is a debilitating condition for which no effective treatment has been found. We hypothesised that re-engagement of central and peripheral circuitry involved in motor execution could reduce phantom limb pain via competitive plasticity and reversal of cortical reorganisation. Patients with upper limb amputation and known chronic intractable phantom limb pain were recruited at three clinics in Sweden and one in Slovenia. Patients received 12 sessions of phantom motor execution using machine learning, augmented and virtual reality, and serious gaming. Changes in intensity, frequency, duration, quality, and intrusion of phantom limb pain were assessed by the use of the numeric rating scale, the pain rating index, the weighted pain distribution scale, and a study-specific frequency scale before each session and at follow-up interviews 1, 3, and 6 months after the last session. Changes in medication and prostheses were also monitored. Results are reported using descriptive statistics and analysed by non-parametric tests. The trial is registered at ClinicalTrials.gov, number NCT02281539. Between Sept 15, 2014, and April 10, 2015, 14 patients with intractable chronic phantom limb pain, for whom conventional treatments failed, were enrolled. After 12 sessions, patients showed statistically and clinically significant improvements in all metrics of phantom limb pain. Phantom limb pain decreased from pre-treatment to the last treatment session by 47% (SD 39; absolute mean change 1·0 [0·8]; p=0·001) for weighted pain distribution, 32% (38; absolute mean change 1·6 [1·8]; p=0·007) for the numeric rating scale, and 51% (33; absolute mean change 9·6 [8·1]; p=0·0001) for the pain rating index. The numeric rating scale score for intrusion of phantom limb pain in activities of daily living and sleep was reduced by 43% (SD 37; absolute mean change 2·4 [2·3]; p=0·004) and 61% (39; absolute mean change 2·3 [1·8]; p=0·001), respectively. Two of four

  12. A computational model unifies apparently contradictory findings concerning phantom pain

    National Research Council Canada - National Science Library

    Boström, Kim J; de Lussanet, Marc H E; Weiss, Thomas; Puta, Christian; Wagner, Heiko

    2014-01-01

    ...) as a cause of phantom pain. However, it was recently found that BOLD activity during voluntary movements of the phantom positively correlates with phantom pain rating, giving rise to a model of persistent representation...

  13. Efficacy of gabapentin for treatment of adults with phantom limb pain.

    Science.gov (United States)

    Abbass, Kim

    2012-12-01

    To evaluate the effectiveness of gabapentin in adults with phantom limb pain. A PubMed search (1966-September 2012) was conducted using the key words phantom limb pain and gabapentin. Search limits were English language, humans, adult, clinical trials, and randomized controlled trial. Randomized controlled trials that studied the effectiveness of gabapentin in adults with phantom limb pain were identified and selected. Primary outcomes were associated with pain. Pediatric population studies were excluded. Three studies, with a total of 89 patients, were reviewed. All studies employed a pain rating scale to determine the primary outcome. Results varied. One crossover study reported a significant difference in pain intensity at 6 weeks compared with baseline (p phantom limb pain. A strong recommendation for the effectiveness of gabapentin in phantom limb pain cannot be ascertained until more methodologically sound studies are executed in this population.

  14. [A dynamic phantom for computer tomography].

    Science.gov (United States)

    Nüsslin, F

    1981-06-01

    A phantom is described which has been developed for investigating factors depending on the scanner itself and on the scanned object which potentially influence the kind and the extent of motion artefacts on the CT-image. Additionally, the phantom may be applied to qualify assurance measurements in computer tomography. A cylindrical insert mounted on a motor driven axis is fitted centrally in a cylindrical block machined from lucite. Two interchangeable inserts are available, one containing test objects made of various materials, and another one containing small vessels which can be filled with test solutions. The insert positioned in the phantom can rotate either continuously or with the direction of motion being altered periodically. Speed, frequency and arc can be varied within wide limits. Examples demonstrating the static and the dynamic mode of the phantom are shown. By means of the dynamic phantom it is quite easy to directly determine the scan-time of a Computer tomograph.

  15. Development of a universal medical X-ray imaging phantom prototype.

    Science.gov (United States)

    Groenewald, Annemari; Groenewald, Willem A

    2016-11-08

    Diagnostic X-ray imaging depends on the maintenance of image quality that allows for proper diagnosis of medical conditions. Maintenance of image quality requires quality assurance programs on the various X-ray modalities, which consist of pro-jection radiography (including mobile X-ray units), fluoroscopy, mammography, and computed tomography (CT) scanning. Currently a variety of modality-specific phantoms are used to perform quality assurance (QA) tests. These phantoms are not only expensive, but suitably trained personnel are needed to successfully use them and interpret the results. The question arose as to whether a single universal phantom could be designed and applied to all of the X-ray imaging modalities. A universal phantom would reduce initial procurement cost, possibly reduce the time spent on QA procedures and simplify training of staff on the single device. The aim of the study was to design and manufacture a prototype of a universal phantom, suitable for image quality assurance in general X-rays, fluoroscopy, mammography, and CT scanning. The universal phantom should be easy to use and would enable automatic data analysis, pass/fail reporting, and corrective action recommendation. In addition, a universal phantom would especially be of value in low-income countries where finances and human resources are limited. The design process included a thorough investigation of commercially available phantoms. Image quality parameters necessary for image quality assurance in the different X-ray imaging modalities were determined. Based on information obtained from the above-mentioned investigations, a prototype of a universal phantom was developed, keeping ease of use and reduced cost in mind. A variety of possible phantom housing and insert materials were investigated, considering physical properties, machinability, and cost. A three-dimensional computer model of the first phantom prototype was used to manufacture the prototype housing and inserts. Some of the

  16. Accurately characterized optical tissue phantoms: how, why and when?

    Science.gov (United States)

    Bouchard, Jean-Pierre; Veilleux, Isra"l.; Noiseux, Isabelle; Mermut, Ozzy

    2011-03-01

    Optical tissue phantoms are very important tools for the development of biomedical imaging applications. Optical phantoms are often used as ground truth against which instruments results can be compared. It is therefore important that the optical properties of reference phantoms be measured in a manner that is traceable to the international system of units. SI traceability insures long term consistency of results and will therefore improve the effectiveness of diffuse optics research effort more effective by reducing unwanted variability in the data produced and shared by the community. The ultimate benefit of rigorous SI traceability is the reduction of variability in the data produced by novel diagnostic devices, which will in turn increase the statistical power of clinical trials aiming at validating their clinical usefulness. SI traceability, and therefore uncertainty analysis, is also relevant to traceability aspects mandated by FDA regulations. SI traceability is achieved through a thorough analysis of the measurement principle and its potential error sources. The uncertainty analysis should be ultimately validated by inter-laboratory comparison until a consensus is attained on the best practices for measuring the optical properties of tissue phantoms.

  17. Phantom limb pain: a nursing perspective.

    Science.gov (United States)

    Virani, Anila; Green, Theresa; Turin, Tanvir C

    2014-09-09

    Phantom limb pain (PLP) is a neuropathic pain condition occurring after amputation of a limb. PLP affects amputees' quality of life and results in loss of productivity and psychological distress. The origin of pain from a non-existing limb creates a challenging situation for both patients and nurses. It is imperative to provide patients and nurses with the knowledge that PLP is a real phenomenon that requires care and treatment. This knowledge will lead to reduced problems for patients by allowing them to talk about PLP and ask for help when needed. Understanding of this phenomenon will enable nurses to appreciate the unique features of this form of neuropathic pain and apply appropriate techniques to promote effective pain management. Performing accurate and frequent assessments to understand the unique characteristics of PLP, displaying a non-judgemental attitude towards patients and teaching throughout the peri-operative process are significant nursing interventions.

  18. Dosimetry analysis of panoramic-imaging devices in different-sized phantoms.

    Science.gov (United States)

    Wahid, Muizz A; Choi, Ella; MacDonald, David S; Ford, Nancy L

    2017-03-01

    The aim of this study is to measure the radiographic dose in adult, adolescent, and child head-sized PMMA phantoms for three panoramic-imaging devices: the panoramic mode on two CBCT machines (Carestream 9300 and i-CAT NG) and the Planmeca ProMax 2D. A SEDENTEXCT dose index adult phantom and custom-built adolescent and pediatric PMMA dosimetry phantoms were used. Panoramic radiographs were performed using a Planmeca ProMax 2D and the panoramic mode on a Carestream 9300 CBCT and an i-CAT NG using the protocols used clinically. Point dose measurements were performed at the center, around the periphery and on the surface of each phantom using a thimble ionization chamber. Five repeat measurements were taken at each location. For each machine, single-factor ANOVA was conducted to determine dose differences between protocols in each phantom, as well as determine the differences in absorbed dose when the same protocol was used for different-sized phantoms. For any individual phantom, using protocols with lower kVp, mA, or acquisition times resulted in statistically significant dose savings, as expected. When the same protocol was used for different-sized phantoms, the smaller phantom had a higher radiation dose due to less attenuation of x-rays by the smaller phantom and differences in the positioning of the ion chamber relative to the focal trough. The panoramic-mode on the CBCT machines produce images suitable for clinical use with similar dose levels to the stand-alone panoramic device. Significant dose savings may result by selecting age- and size- appropriate protocols for pediatric patients, but a wider range of protocols for children and adolescents may be beneficial. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  19. Material-specific Conversion Factors for Different Solid Phantoms Used in the Dosimetry of Different Brachytherapy Sources

    Directory of Open Access Journals (Sweden)

    Sedigheh Sina

    2015-07-01

    Full Text Available Introduction Based on Task Group No. 43 (TG-43U1 recommendations, water phantom is proposed as a reference phantom for the dosimetry of brachytherapy sources. The experimental determination of TG-43 parameters is usually performed in water-equivalent solid phantoms. The purpose of this study was to determine the conversion factors for equalizing solid phantoms to water. Materials and Methods TG-43 parameters of low- and high-energy brachytherapy sources (i.e., Pd-103, I-125 and Cs-137 were obtained in different phantoms, using Monte Carlo simulations. The brachytherapy sources were simulated at the center of different phantoms including water, solid water, poly(methyl methacrylate, polystyrene and polyethylene. Dosimetric parameters such as dose rate constant, radial dose function and anisotropy function of each source were compared in different phantoms. Then, conversion factors were obtained to make phantom parameters equivalent to those of water. Results Polynomial coefficients of conversion factors were obtained for all sources to quantitatively compare g(r values in different phantom materials and the radial dose function in water. Conclusion Polynomial coefficients of conversion factors were obtained for all sources to quantitatively compare g(r values in different phantom materials and the radial dose function in water.

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

    Energy Technology Data Exchange (ETDEWEB)

    Norris, Hannah, E-mail: Hannah.norris@duke.edu; Zhang, Yakun; Bond, Jason; Sturgeon, Gregory M.; Samei, E.; Segars, W. P. [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Minhas, Anum; Frush, D. [Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Tward, Daniel J.; Ratnanather, J. T.; Miller, M. I. [Center for Imaging Science, Johns Hopkins University, Baltimore, Maryland 21218 (United States)

    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

  1. Asian Art on Display

    DEFF Research Database (Denmark)

    Borggreen, Gunhild Ravn

    2010-01-01

    Med udgangspunkt i seminaret Visualising Asian Modernity diskuteres forholdet mellem antropologi og samtidskunst i lyset af hvorledes asiatisk kunst fremvises og formidles i vestlig og dansk sammenhæng....

  2. Profile: Asian Americans

    Science.gov (United States)

    ... and diabetes. Asian Americans also have a high prevalence of the following conditions and risk factors: chronic obstructive pulmonary disease, hepatitis B, HIV/AIDS, smoking, tuberculosis, and liver ...

  3. Central Asian Republic Info

    Data.gov (United States)

    US Agency for International Development — CAR Info is designed and managed by the Central Asian Republic Mission to fill in the knowledge and reporting gaps in existing agency systems for that Mission. It...

  4. Evaluation of tomosynthesis elastography in a breast-mimicking phantom

    Energy Technology Data Exchange (ETDEWEB)

    Engelken, Florian Jan, E-mail: florian.engelken@charite.de [Department of Radiology, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin (Germany); Sack, Ingolf, E-mail: ingolf.sack@charite.de [Department of Radiology, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin (Germany); Klatt, Dieter, E-mail: dieter.klatt@charite.de [Department of Radiology, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin (Germany); Fischer, Thomas, E-mail: thom.fischer@charite.de [Department of Radiology, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin (Germany); Fallenberg, Eva Maria, E-mail: eva.fallenberg@charite.de [Department of Radiology, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin (Germany); Bick, Ulrich, E-mail: ulrich.bick@charite.de [Department of Radiology, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin (Germany); Diekmann, Felix, E-mail: felix.diekmann@charite.de [Department of Radiology, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin (Germany)

    2012-09-15

    Objective: To evaluate whether measurement of strain under static compression in tomosynthesis of a breast-mimicking phantom can be used to distinguish tumor-simulating lesions of different elasticities and to compare the results to values predicted by rheometric analysis as well as results of ultrasound elastography. Materials and methods: We prepared three soft breast-mimicking phantoms containing simulated tumors of different elasticities. The phantoms were imaged using a wide angle tomosynthesis system with increasing compression settings ranging from 0 N to 105 N in steps of 15 N. Strain of the inclusions was measured in two planes using a commercially available mammography workstation. The elasticity of the phantom matrix and inclusion material was determined by rheometric analysis. Ultrasound elastography of the inclusions was performed using two different ultrasound elastography algorithms. Results: Strain at maximal compression was 24.4%/24.5% in plane 1/plane 2, respectively, for the soft inclusion, 19.6%/16.9% for the intermediate inclusion, and 6.0%/10.2% for the firm inclusion. The strain ratios predicted by rheometrical testing were 0.41, 0.83 and 1.26 for the soft, intermediate, and firm inclusions, respectively. The strain ratios obtained for the soft, intermediate, and firm inclusions were 0.72 ± 0.13, 1.02 ± 0.21 and 2.67 ± 1.70, respectively for tomosynthesis elastography, 0.91, 1.64 and 2.07, respectively, for ultrasound tissue strain imaging, and 0.97, 2.06 and 2.37, respectively, for ultrasound real-time elastography. Conclusions: Differentiation of tumor-simulating inclusions by elasticity in a breast mimicking phantom may be possible by measuring strain in tomosynthesis. This method may be useful for assessing elasticity of breast lesions tomosynthesis of the breast.

  5. Are ethnic and gender specific equations needed to derive fat free mass from bioelectrical impedance in children of South asian, black african-Caribbean and white European origin? Results of the assessment of body composition in children study.

    Directory of Open Access Journals (Sweden)

    Claire M Nightingale

    Full Text Available BACKGROUND: Bioelectrical impedance analysis (BIA is a potentially valuable method for assessing lean mass and body fat levels in children from different ethnic groups. We examined the need for ethnic- and gender-specific equations for estimating fat free mass (FFM from BIA in children from different ethnic groups and examined their effects on the assessment of ethnic differences in body fat. METHODS: Cross-sectional study of children aged 8-10 years in London Primary schools including 325 South Asians, 250 black African-Caribbeans and 289 white Europeans with measurements of height, weight and arm-leg impedance (Z; Bodystat 1500. Total body water was estimated from deuterium dilution and converted to FFM. Multilevel models were used to derive three types of equation {A: FFM = linear combination(height+weight+Z; B: FFM = linear combination(height(2/Z; C: FFM = linear combination(height(2/Z+weight}. RESULTS: Ethnicity and gender were important predictors of FFM and improved model fit in all equations. The models of best fit were ethnicity and gender specific versions of equation A, followed by equation C; these provided accurate assessments of ethnic differences in FFM and FM. In contrast, the use of generic equations led to underestimation of both the negative South Asian-white European FFM difference and the positive black African-Caribbean-white European FFM difference (by 0.53 kg and by 0.73 kg respectively for equation A. The use of generic equations underestimated the positive South Asian-white European difference in fat mass (FM and overestimated the positive black African-Caribbean-white European difference in FM (by 4.7% and 10.1% respectively for equation A. Consistent results were observed when the equations were applied to a large external data set. CONCLUSIONS: Ethnic- and gender-specific equations for predicting FFM from BIA provide better estimates of ethnic differences in FFM and FM in children, while generic equations

  6. Computerized quantitative evaluation of mammographic accreditation phantom images

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yongbum; Tsai, Du-Yih; Shinohara, Norimitsu [Department of Radiological Technology, School of Health Sciences, Niigata University, 2-746 Asahimachidori, Chuouku, Niigata 951-8518 (Japan); Department of Radiological Technology, Gifu Univesity of Medical Science, 1-795 Hiraga-aza-nagamine, Seki, Gifu 501-3892 (Japan)

    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.

  7. [Evaluation of ultrasound hyperthermia system with a phantom model].

    Science.gov (United States)

    Ono, S; Hirose, T; Shiba, T; Kuriya, K; Watanabe, K

    1996-03-01

    Ultrasound (US) hyperthermia is a local heating method that has recently been introduced into clinical practice. A prototype and modified version of this system using a phantom model (agar with bone inserted) were evaluated. The prototype system consists of a power delivery unit (0.5 MHz frequency) with a circulating cooled water bolus. This system heats a shallow area irrespective of power output, but has a tendency to overheat the phantom surface. We incorporated three modifications into the prototype. The modified type has three frequency applicators (0.5, 1.0, 1.5MHz) and a secondary bolus. Aluminum-urethane shields were used to cover the phantom surface located over bone preventing overheating of bone. By changing the applicator's US frequency, we could change the depth of the heating area. Overheating of the phantom surface and bone thus was avoided. These results suggest that our modified US hyperthermia system with multiple frequency applicators, a secondary bolus and aluminum-urethane shields provided a good heating pattern.

  8. Gravitational Quasinormal Modes of Regular Phantom Black Hole

    Directory of Open Access Journals (Sweden)

    Jin Li

    2017-01-01

    Full Text Available We investigate the gravitational quasinormal modes (QNMs for a type of regular black hole (BH known as phantom BH, which is a static self-gravitating solution of a minimally coupled phantom scalar field with a potential. The studies are carried out for three different spacetimes: asymptotically flat, de Sitter (dS, and anti-de Sitter (AdS. In order to consider the standard odd parity and even parity of gravitational perturbations, the corresponding master equations are derived. The QNMs are discussed by evaluating the temporal evolution of the perturbation field which, in turn, provides direct information on the stability of BH spacetime. It is found that in asymptotically flat, dS, and AdS spacetimes the gravitational perturbations have similar characteristics for both odd and even parities. The decay rate of perturbation is strongly dependent on the scale parameter b, which measures the coupling strength between phantom scalar field and the gravity. Furthermore, through the analysis of Hawking radiation, it is shown that the thermodynamics of such regular phantom BH is also influenced by b. The obtained results might shed some light on the quantum interpretation of QNM perturbation.

  9. The Asian Face Lift

    OpenAIRE

    Bergeron, Léonard; Chen, Yu-Ray

    2009-01-01

    The face-lift procedure (rhytidectomy) is increasingly popular in Asia. There is extensive literature on different techniques in Western patients. Cultural and anthropomorphologic differences between Asian and Caucasians require the adaptation of current techniques to obtain a satisfactory outcome for both the patient and the surgeon. This article therefore attempts to define important differences between Asians and Caucasians in terms of signs of facial aging, perception of beauty, and surgi...

  10. Factors associated with phantom limb pain: a 31/2-year prospective study.

    Science.gov (United States)

    Bosmans, Joline C; Geertzen, Jan H B; Post, Wendy J; van der Schans, Cees P; Dijkstra, Pieter U

    2010-05-01

    To analyse the prevalence of phantom (limb) pain over time and to analyse factors associated with phantom (limb) pain in a prospective cohort of amputees. A multicentre longitudinal study. One hundred and thirty-four patients scheduled for amputation were included. Patients filled in questionnaires before amputation, and postal questionnaires six months, 1(1/2) years and 2(1/2) years to a maximum of 3(1/2) years after amputation. Preoperative assessment included patients' characteristics, date, side and level of, and reason for amputation. The follow-up questionnaires assessed the frequencies of the experienced phantom pain, prosthetic use and walking distance. The occurrence of phantom pain was defined as phantom pain a few times a day or more frequently. Pre- and postoperative questionnaires were available filled in by 85 amputees (33 females and 52 males). The percentage of lower limb amputees with phantom pain was the highest at six months after amputation, and of upper limb amputees at 1(1/2) years. In general, more women than men experienced phantom pain. One and a half years and 2(1/2) years after amputation the highest percentages of the lower limb amputees used their prosthesis more than 4 hours a day (66%), after that time this percentage decreased to 60%. The results of the two-level logistic regression analysis to predict phantom pain show that phantom pain was less frequently present in men (odds ratio (OR) = 0.12), in lower limb amputees (OR = 0.14) and that it decreased in due course (OR = 0.53 for 1 year). Protective factors for phantom pain are: being male, having a lower limb amputation and the time elapsed since amputation.

  11. SU-C-209-07: Phantoms for Digital Breast Tomosynthesis Imaging System Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Jacobson, D; Liu, Y [Medical College of Wisconsin, Milwaukee, WI (United States)

    2016-06-15

    Purpose: Digital Breast Tomosynthesis (DBT) is gaining importance in breast imaging. There is a need for phantoms that can be used for image evaluation and comparison. Existing commercially available phantoms for DBT are expensive and may lack clinically relevant test objects. The purpose of this study is to develop phantoms for DBT evaluation. Methods Four phantoms have been designed and constructed to assess the image quality (IQ) of two DBT systems. The first contains a spiral of 0.3 mm SiC beads in gelatin to measure the tomographic slice thickness profile and uniformity of coverage in a series of tomographic planes. The second contains simulated tumors inclined with respect to the phantom base to assess tomographic image quality. The third has a tilted array of discs with varying contrast and diameter. This phantom was imaged alone and in a stack of TE slabs giving 2 to 10 cm thickness. The fourth has a dual wedge of glandular and adipose simulating materials. One wedge contains discs with varying diameter and thickness; the other supports a mass with six simulated spicules of varying size and a cluster of simulated calcifications. The simulated glandular tissue material varies between 35 and 100% of the total thickness (5.5 cm). Results: All phantoms were scanned successfully. The best IQ comparison was achieved with the dual wedge phantom as demonstrated by the spiculated mass and calcifications. Images were evaluated by two radiologists and one physicist. The projection images and corresponding set of tomographic planes were comparable and the synthesized projection images were inferior to the projection images for both systems. Conclusion: Four phantoms were designed, constructed and imaged on two DBT systems. They successfully demonstrated performance differences between two systems, and between true and synthesized projection images. Future work will incorporate these designs into a single phantom.

  12. Walled Carotid Bifurcation Phantoms for Imaging Investigations of Vessel Wall Motion and Blood Flow Dynamics.

    Science.gov (United States)

    Chee, Adrian J Y; Ho, Chung Kit; Yiu, Billy Y S; Yu, Alfred C H

    2016-07-18

    As a major application domain of vascular ultrasound, the carotid artery has long been the subject of anthropomorphic phantom design. It is nevertheless not trivial to develop walled carotid phantoms that are compatible for use in integrative imaging of carotid wall motion and flow dynamics. In this paper, we present a novel phantom design protocol that can enable efficient fabrication of walled carotid bifurcation phantoms with: (i) high acoustic compatibility, (ii) artery-like vessel elasticity, and (iii) stenotic narrowing feature. Our protocol first involved direct fabrication of the vessel core and an outer mold using computer-aided design tools and 3-D printing technology; these built parts were then used to construct an elastic vessel tube through investment casting of a polyvinyl alcohol containing mixture, and an agar-gelatin tissue mimicking slab was formed around the vessel tube. For demonstration, we applied our protocol to develop a set of healthy and stenosed (25%, 50%, 75%) carotid bifurcation phantoms. Plane wave imaging experiments were performed on these phantoms using an ultrasound scanner with channel-level configurability. Results show that the wall motion dynamics of our phantoms agreed with pulse wave propagation in an elastic vessel (pulse wave velocity of 4.67±0.71 m/s measured at the common carotid artery), and their flow dynamics matched the expected ones in healthy and stenosed bifurcation (recirculation and flow jet formation observed). Integrative imaging of vessel wall motion and blood flow dynamics in our phantoms was also demonstrated, from which we observed fluid-structure interaction differences between healthy and diseased bifurcation phantoms. These findings show that the walled bifurcation phantoms developed with our new protocol are useful in vascular imaging studies that individually or jointly assess wall motion and flow dynamics.

  13. Estimation of computed tomography dose in various phantom shapes and compositions

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chang Lae [Dept. of Radiological Science, Yonsei University, Seoul (Korea, Republic of)

    2017-03-15

    The purpose of this study was to investigate CTDI (computed tomography dose index at center) for various phantom shapes, sizes, and compositions by using GATE (geant4 application for tomographic emission) simulations. GATE simulations were performed for various phantom shapes (cylinder, elliptical, and hexagonal prism PMMA phantoms) and phantom compositions (water, PMMA, polyethylene, polyoxymethylene) with various diameters (1-50 cm) at various kVp and mAs levels. The CTDI100center values of cylinder, elliptical, and hexagonal prism phantom at 120 kVp, 200 mAs resulted in 11.1, 13.4, and 12.2 mGy, respectively. The volume is the same, but CTDI{sub 100center} values are different depending on the type of phantom. The water, PMMA, and polyoxymethylene phantom CTDI{sub 100center} values were relatively low as the material density increased. However, in the case of Polyethylene, the CTDI{sub 100center} value was higher than that of PMMA at diameters exceeding 15 cm (CTDI{sub 100center} : 35.0 mGy). And a diameter greater than 30 cm (CTDI{sub 100center} : 17.7 mGy) showed more CTDI{sub 100center} than Water. We have used limited phantoms to evaluate CT doses. In this study, CTDI{sub 100center} values were estimated and simulated by GATE simulation according to the material and shape of the phantom. CT dosimetry can be estimated more accurately by using various materials and phantom shapes close to human body.

  14. Agency over Phantom Limb Enhanced by Short-Term Mirror Therapy

    Directory of Open Access Journals (Sweden)

    Shu Imaizumi

    2017-10-01

    Full Text Available Most amputees experience phantom limb, whereby they feel that the amputated limb is still present. In some cases, these experiences include pain that can be alleviated by “mirror therapy.” Mirror therapy consists of superimposing a mirrored image of the moving intact limb onto the phantom limb. This therapy provides a closed loop between the motor command to the amputated limb and its predicted visual feedback. This loop is also involved in the sense of agency, a feeling of controlling one’s own body. However, it is unclear how mirror therapy is related to the sense of agency over a phantom limb. Using mirror therapy, we investigated phantom limb pain and the senses of agency and ownership (i.e., a feeling of having one’s own body of the phantom limb. Nine upper-limb amputees, five of whom reported recent phantom limb pain, underwent a single 15-min trial of mirror therapy. Before and after the trial, the participants completed a questionnaire regarding agency, ownership, and pain related to their phantom limb. They reported that the sense of agency over the phantom limb increased following the mirror therapy trial, while the ownership slightly increased but not as much as did the agency. The reported pain did not change; that is, it was comparably mild before and after the trial. These results suggest that short-term mirror therapy can, at least transiently, selectively enhance the sense of agency over a phantom limb, but may not alleviate phantom limb pain.

  15. Teflon cylindrical phantom for delivery quality assurance of stereotactic body radiotherapy (SBRT).

    Science.gov (United States)

    Lack, Danielle W; Kakakhel, Ali; Starin, Ross; Snyder, Michael

    2014-01-06

    At our institution the standard delivery quality assurance (DQA) procedure for tomotherapy plans is accomplished with a water equivalent phantom, EDR2 film, and ion chamber point-dose measurements. Most plans deliver at most 5 Gy to the dose plane; however, recently a stereotactic body radiotherapy (SBRT) protocol has produced plans delivering upwards of 12 Gy to the film plane. EDR2 film saturates at a dose of ~ 7 Gy, requiring a modification of our DQA procedure for SBRT plans. To reduce the dose to the film plane and accommodate a possible move to SBRT using Varian RapidArc, a Teflon phantom has been constructed and tested. Our Teflon phantom is cylindrical in shape and of a similar design to the standard phantom. The phantom was MVCT scanned on the TomoTherapy system with images imported into the TomoTherapy and Varian Eclipse planning systems. Phantom images were smoothed to reduce artifacts for treatment planning purposes. Verification SBRT plans were delivered with film and point-dose benchmarked against the standard procedure. Verification tolerance criteria were 3% dose difference for chamber measurements and a gamma pass rate > 90% for film (criteria: 3 mm DTA, 3% dose difference, 10% threshold). The phantom sufficiently reduced dose to the film plane for DQA of SBRT plans. Both planning systems calculated accurate point doses in phantom, with the largest differences being 2.4% and 4.4% for TomoTherapy and Rapid Arc plans. Measured dose distributions correlated well with planning system calculations (γ < 1 for > 95%). These results were comparable to the standard phantom. The Teflon phantom appears to be a potential option for SBRT DQA. Preliminary data show that the planning systems are capable of calculating point doses in the Teflon, and the dose to the film plane is reduced sufficiently to allow for a direct measured DQA without the need for dose rescaling.

  16. A deformable head and neck phantom with in-vivo dosimetry for adaptive radiotherapy quality assurance

    Energy Technology Data Exchange (ETDEWEB)

    Graves, Yan Jiang [Center for Advanced Radiotherapy Technologies and Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California 92037-0843 and Department of Physics, University of California San Diego, La Jolla, California 92093 (United States); Smith, Arthur-Allen; Mcilvena, David; Manilay, Zherrina; Lai, Yuet Kong [Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California 92093 (United States); Rice, Roger; Mell, Loren; Cerviño, Laura, E-mail: lcervino@ucsd.edu, E-mail: steve.jiang@utsouthwestern.edu [Center for Advanced Radiotherapy Technologies and Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California 92037-0843 (United States); Jia, Xun; Jiang, Steve B., E-mail: lcervino@ucsd.edu, E-mail: steve.jiang@utsouthwestern.edu [Center for Advanced Radiotherapy Technologies and Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California 92037-0843 and Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas 75235 (United States)

    2015-04-15

    Purpose: Patients’ interfractional anatomic changes can compromise the initial treatment plan quality. To overcome this issue, adaptive radiotherapy (ART) has been introduced. Deformable image registration (DIR) is an important tool for ART and several deformable phantoms have been built to evaluate the algorithms’ accuracy. However, there is a lack of deformable phantoms that can also provide dosimetric information to verify the accuracy of the whole ART process. The goal of this work is to design and construct a deformable head and neck (HN) ART quality assurance (QA) phantom with in vivo dosimetry. Methods: An axial slice of a HN patient is taken as a model for the phantom construction. Six anatomic materials are considered, with HU numbers similar to a real patient. A filled balloon inside the phantom tissue is inserted to simulate tumor. Deflation of the balloon simulates tumor shrinkage. Nonradiopaque surface markers, which do not influence DIR algorithms, provide the deformation ground truth. Fixed and movable holders are built in the phantom to hold a diode for dosimetric measurements. Results: The measured deformations at the surface marker positions can be compared with deformations calculated by a DIR algorithm to evaluate its accuracy. In this study, the authors selected a Demons algorithm as a DIR algorithm example for demonstration purposes. The average error magnitude is 2.1 mm. The point dose measurements from the in vivo diode dosimeters show a good agreement with the calculated doses from the treatment planning system with a maximum difference of 3.1% of prescription dose, when the treatment plans are delivered to the phantom with original or deformed geometry. Conclusions: In this study, the authors have presented the functionality of this deformable HN phantom for testing the accuracy of DIR algorithms and verifying the ART dosimetric accuracy. The authors’ experiments demonstrate the feasibility of this phantom serving as an end

  17. MO-F-CAMPUS-T-01: IROC Houston QA Center’s Anthropomorphic Proton Phantom Program

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    Lujano, C; Hernandez, N; Keith, T; Nguyen, T; Taylor, P; Molineu, A; Followill, D [UT MD Anderson Cancer Center, Houston, TX (United States)

    2015-06-15

    Purpose: To describe the proton phantoms that IROC Houston uses to approve and credential proton institutions to participate in NCI-sponsored clinical trials. Methods: Photon phantoms cannot necessarily be used for proton measurements because protons react differently than photons in some plastics. As such plastics that are tissue equivalent for protons were identified. Another required alteration is to ensure that the film dosimeters are housed in the phantom with no air gap to avoid proton streaming. Proton-equivalent plastics/materials used include RMI Solid Water, Techron HPV, blue water, RANDO soft tissue material, balsa wood, compressed cork and polyethylene. Institutions wishing to be approved or credentialed request a phantom and are prioritized for delivery. At the institution, the phantom is imaged, a treatment plan is developed, positioned on the treatment couch and the treatment is delivered. The phantom is returned and the measured dose distributions are compared to the institution’s electronically submitted treatment plan dosimetry data. Results: IROC Houston has developed an extensive proton phantom approval/credentialing program consisting of five different phantoms designs: head, prostate, lung, liver and spine. The phantoms are made with proton equivalent plastics that have HU and relative stopping powers similar (within 5%) of human tissues. They also have imageable targets, avoidance structures, and heterogeneities. TLD and radiochromic film are contained in the target structures. There have been 13 head, 33 prostate, 18 lung, 2 liver and 16 spine irradiations with either passive scatter, or scanned proton beams. The pass rates have been: 100%, 69.7%, 72.2%, 50%, and 81.3%, respectively. Conclusion: IROC Houston has responded to the recent surge in proton facilities by developing a family of anthropomorphic phantoms that are able to be used for remote audits of proton beams. Work supported by PHS grant CA10953 and CA081647.

  18. Posttraumatic syringomyelia: volumetric phantom and patient studies using MR imaging

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    Freund, Michael; Habicht, Dirk; Kalvine, Kira; Sartor, Klaus [Department of Neuroradiology, Medical School, University of Heidelberg (Germany); Aschoff, Alfred [Department of Neurosurgery, Medical School, University of Heidelberg (Germany)

    2002-12-01

    The purpose of this study was to determine the volume of posttraumatic syringomyelia (PTS) based on standard MRI data acquisitions, and to compare the volumes with the neurological deficits of the patients. Firstly, phantom studies were performed using routine T1- (T1W; TR 500 ms, TE 13 ms) spin-echo (SE) images, 3D gradient-echo (GE) images and T2-weighted (T2W) turbo spin-echo (TSE) images (TR 3000 ms, TE 130 ms), in the sagittal plane. The slices were interleaved so that there was no gap. Twelve phantoms simulating a PTS were constructed and filled with fluid. Each volume was exactly measured immediately prior to filling (volumes: 3600-74,000 mm{sup 3}, mean 27,500 mm{sup 3}). In the clinical study 32 patients with PTS were examined using the same protocol. Patients were supine and a phased-array coil was used. The phantom studies revealed measurement errors of within 35%. There were problems defining the boundaries in the small and irregular phantoms as well as in small and irregular PTS, and due to the partial-volume averaging effect. The two small irregular phantoms could only be measured on the axial images. The T2W images in the axial plane showed the best results: measurement accuracy 92%. In the clinical study all examinations were technically successful. The volumes of the PTS ranged between 200 and 19,800 mm{sup 3}; the mean volume was 4075 mm{sup 3}. Our initial results show that the volume measurement of a PTS using standard MRI sequences can help generate more objective and accurate measures of spinal cord lesions, and this may enhance the sensitivity of MRI in detecting disease progression or regression after treatment. (orig.)

  19. Developing a Verification and Training Phantom for Gynecological Brachytherapy System

    Directory of Open Access Journals (Sweden)

    Mahbobeh Nazarnejad

    2012-03-01

    Full Text Available Introduction Dosimetric accuracy is a major issue in the quality assurance (QA program for treatment planning systems (TPS. An important contribution to this process has been a proper dosimetry method to guarantee the accuracy of delivered dose to the tumor. In brachytherapy (BT of gynecological (Gyn cancer it is usual to insert a combination of tandem and ovoid applicators with a complicated geometry which makes their dosimetry verification difficult and important. Therefore, evaluation and verification of dose distribution is necessary for accurate dose delivery to the patients. Materials and Methods The solid phantom was made from Perspex slabs as a tool for intracavitary brachytherapy dosimetric QA. Film dosimetry (EDR2 was done for a combination of ovoid and tandem applicators introduced by Flexitron brachytherapy system. Treatment planning was also done with Flexiplan 3D-TPS to irradiate films sandwiched between phantom slabs. Isodose curves obtained from treatment planning system and the films were compared with each other in 2D and 3D manners. Results The brachytherapy solid phantom was constructed with slabs. It was possible to insert tandems and ovoids loaded with radioactive source of Ir-192 subsequently. Relative error was 3-8.6% and average relative error was 5.08% in comparison with the films and TPS isodose curves. Conclusion Our results showed that the difference between TPS and the measurements is well within the acceptable boundaries and below the action level according to AAPM TG.45. Our findings showed that this phantom after minor corrections can be used as a method of choice for inter-comparison analysis of TPS and to fill the existing gap for accurate QA program in intracavitary brachytherapy. The constructed phantom also showed that it can be a valuable tool for verification of accurate dose delivery to the patients as well as training for brachytherapy residents and physics students.

  20. Galactic dark matter in the phantom field

    Science.gov (United States)

    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.

  1. A phantom design for validating colonoscopy tracking

    Science.gov (United States)

    Liu, Jianfei; Subramanian, Kalpathi R.; Yoo, Terry S.

    2012-03-01

    Phantom experiments are useful and frequently used in validating algorithms or techniques in applications where it is difficult or impossible to generate accurate ground-truth. In this work we present a phantom design and experiments to validate our colonoscopy tracking algorithms, that serve to keep both virtual colonoscopy and optical colonoscopy images aligned (in location and orientation). We describe the construction of two phantoms, capable of respectively moving along a straight and a curved path. The phantoms are motorized so as to be able to move at a near constant speed. Experiments were performed at three speeds: 10, 15 and 20mm/sec, to simulate motion velocities during colonoscopy procedures. The average velocity error was within 3mm/sec in both straight and curved phantoms. Displacement error was within 7mm over a total distance of 288mm in the straight phantom, and less than 7mm over 287mm in the curved phantom. Multiple trials were performed of each experiment(and their errors averaged) to ensure repeatability.

  2. Anxiety and depression in patients with amputated limbs suffering from phantom pain: A comparative study with non-phantom chronic pain

    Directory of Open Access Journals (Sweden)

    Hadi Kazemi

    2013-01-01

    Conclusion : Our results indicate that depression and anxiety are not more common in PLP patients, whereas they are more prevalent in subjects with non-phantom chronic pain. These lower levels of anxiety and depression in PLP compared with chronic pain is a new finding that needs to be evaluated further, which may lead to new insights into the pathogenesis of phantom pain in further studies.

  3. The reference phantoms: voxel vs polygon.

    Science.gov (United States)

    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. © The International Society for Prosthetics and Orthotics.

  4. Twelve-month prevalence of psychiatric disorders and treatment-seeking among Asian Americans/Pacific Islanders in the United States: Results from the National Epidemiological Survey on Alcohol and Related Conditions

    Science.gov (United States)

    Xu, Yang; Okuda, Mayumi; Hser, Yih-Ing; Hasin, Deborah; Liu, Shang-Min; Grant, Bridget F.; Blanco, Carlos

    2011-01-01

    To compare the 12-month prevalence of psychiatric disorders in Asian Americans/Pacific Islanders in contrast to non–Hispanic whites; and further compare persistence and treatment-seeking rates for psychiatric disorders among Asian American/Pacific Islanders and non-Hispanic whites, analyses from the 2001–2002 National Epidemiologic Survey on Alcohol and Related Conditions, Wave 1 (n =43,093) were conducted for the subsample of 1,332 Asian Americans/Pacific Islanders (596 men and 736 women) and 24,507 non-Hispanic whites (10,845 men and 13,662 women). The past 12-month prevalence for any psychiatric disorder was significantly lower in Asian American/Pacific Islander males and females than non-Hispanic white males and females. Asian American/Pacific Islander males were less likely than non-Hispanic white males to have any mood, anxiety, substance use, and personality disorders, whereas the prevalence of mood disorders among Asian American/Pacific Islander females did not differ from those of non-Hispanic white females. In some cases, such as drug use disorders, both male and female Asian Americans/Pacific Islanders were more likely to have more persistent disorders than non-Hispanic whites. Compared to non-Hispanic white females, Asian American/Pacific Islander females had lower rates of treatment-seeking for any mood/anxiety disorders. Although less prevalent than among non-Hispanic whites, psychiatric disorders are not uncommon among Asian Americans/Pacific Islanders. The lower treatment seeking rates for mood/anxiety disorders in Asian American/Pacific Islander females underscore the unmet needs for psychiatric service among this population. PMID:21238989

  5. Atypical supernumerary phantom limb and phantom limb pain in a patient with spinal cord injury: case report.

    Science.gov (United States)

    Choi, Ja Young; Kim, Hyo In; Lee, Kil Chan; Han, Zee-A

    2013-12-01

    Supernumerary phantom limb (SPL) resulting from spinal cord lesions are very rare, with only sporadic and brief descriptions in the literature. Furthermore, the reported cases of SPL typically occurred in neurologically incomplete spinal cord patients. Here, we report a rare case of SPL with phantom limb pain that occurred after traumatic spinal cord injury in a neurologically complete patient. After a traffic accident, a 43-year-old man suffered a complete spinal cord injury with a C6 neurologic level of injury. SPL and associated phantom limb pain occurred 6 days after trauma onset. The patient felt the presence of an additional pair of legs that originated at the hip joints and extended medially, at equal lengths to the paralyzed legs. The intensity of SPL and associated phantom limb pain subsequently decreased after visual-tactile stimulation treatment, in which the patient visually identified the paralyzed limbs and then gently tapped them with a wooden stick. This improvement continued over the 2 months of inpatient treatment at our hospital and the presence of the SPLs was reduced to 20% of the real paralyzed legs. This is the first comprehensive report on SPLs of the lower extremities after neurologically complete spinal cord injury.

  6. Atypical Supernumerary Phantom Limb and Phantom Limb Pain in a Patient With Spinal Cord Injury: Case Report

    Science.gov (United States)

    Choi, Ja Young; Kim, Hyo In; Lee, Kil Chan

    2013-01-01

    Supernumerary phantom limb (SPL) resulting from spinal cord lesions are very rare, with only sporadic and brief descriptions in the literature. Furthermore, the reported cases of SPL typically occurred in neurologically incomplete spinal cord patients. Here, we report a rare case of SPL with phantom limb pain that occurred after traumatic spinal cord injury in a neurologically complete patient. After a traffic accident, a 43-year-old man suffered a complete spinal cord injury with a C6 neurologic level of injury. SPL and associated phantom limb pain occurred 6 days after trauma onset. The patient felt the presence of an additional pair of legs that originated at the hip joints and extended medially, at equal lengths to the paralyzed legs. The intensity of SPL and associated phantom limb pain subsequently decreased after visual-tactile stimulation treatment, in which the patient visually identified the paralyzed limbs and then gently tapped them with a wooden stick. This improvement continued over the 2 months of inpatient treatment at our hospital and the presence of the SPLs was reduced to 20% of the real paralyzed legs. This is the first comprehensive report on SPLs of the lower extremities after neurologically complete spinal cord injury. PMID:24466528

  7. Quality assurance for ultrasound scanners using a durable tissue-mimicking phantom and radial MTF

    Science.gov (United States)

    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.

  8. Hybrid Computational Phantoms Representing the Reference Adult Male and Adult Female: Construction and Applications for Retrospective Dosimetry

    Science.gov (United States)

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

    2013-01-01

    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 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-year Korean volunteer and a 25-year U.S. female patient, respectively, with supplemental high-resolution CT images for 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 (CDC) and International Commission on Radiation Protection (ICRP), respectively. Finally, two hybrid adult male and female phantoms were completed where a total of 8 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

  9. A comparison of brain phantom relative permittivity with CST simulation library and existing research.

    Science.gov (United States)

    Chew, Kim Mey; Seman, Norhudah; Sudirman, Rubita; Yong, Ching Yee

    2014-01-01

    The development of human-like brain phantom is important for data acquisition in microwave imaging. The characteristics of the phantom should be based on the real human body dielectric properties such as relative permittivity. The development of phantom includes the greymatter and whitematter regions, each with a relative permittivity of 38 and 28 respectively at 10 GHz frequency. Results were compared with the value obtained from the standard library of Computer Simulation Technology (CST) simulation application and the existing research by Fernandez and Gabriel. Our experimental results show a positive outcome, in which the proposed mixture was adequate to represent real human brain for data acquisition.

  10. "Imprisoned" in pain: analyzing personal experiences of phantom pain.

    Science.gov (United States)

    Nortvedt, Finn; Engelsrud, Gunn

    2014-11-01

    This article explores the phenomenon of "phantom pain." The analysis is based on personal experiences elicited from individuals who have lost a limb or live with a paralyzed body part. Our study reveals that the ways in which these individuals express their pain experience is an integral aspect of that experience. The material consists of interviews undertaken with men who are living with phantom pain resulting from a traumatic injury. The phenomenological analysis is inspired by Zahavi (J Conscious Stud 8(5-7):151-167, 2001) and Merleau-Ponty (Phenomenology of perception. Routledge and Kegan Paul, London, 1962/2000). On a descriptive level the metaphors these patients invoke to describe their condition reveal immense suffering, such as a feeling of being invaded by insects or of their skin being scorched and stripped from their body. Such metaphors express a dimension of experience concerning the self that is in pain and others whom the sufferer relates to through this pain, as well as the agony that this pain inflicts in the world of lived experience. This pain has had a profound impact on their lives and altered their relationship with self (body), others and the world. Their phantom pain has become a reminder of their formerly intact and functioning body; they describe the contrast between their past and present body as an ambiguous and disturbing experience. We conclude that these sensitive and personalized experiences of phantom pain illuminates how acts of expression--spoken pain--constitute a fundamental dimension of a first-person perspective which contribute to the field of knowledge about "phantom pain".

  11. Internal dosimetry estimates using voxelized reference phantoms for thyroid agents.

    Science.gov (United States)

    Hoseinian-Azghadi, E; Rafat-Motavalli, L; Miri-Hakimabad, H

    2014-05-01

    This work presents internal dosimetry estimates for diagnostic procedures performed for thyroid disorders by relevant radiopharmaceuticals. The organ doses for (131)Iodine, (123)Iodine and (99m)Tc incorporated into the body were calculated for the International Commission on Radiological Protection (ICRP) reference voxel phantoms using the Monte Carlo transport method. A comparison between different thyroid uptakes of iodine in the range of 0-55% was made, and the effect of various techniques for administration of (99m)Tc on organ doses was studied. To investigate the necessity of calculating organ dose from all source regions, the major source organ and its contribution to total dose were specified for each target organ. Moreover, we compared effective dose in ICRP voxel phantoms with that in stylized phantoms. In our method, we directly calculated the organ dose without using the S values or SAFs, as is commonly done. Hence, a distribution of the absorbed dose to entire tissues was obtained. The chord length distributions (CLDs) were also computed for the selected source-target pairs to make comparison across the genders. The results showed that the S values for radionuclides in the thyroid are not sufficient for calculating the organ doses, especially for (123)I and (99m)Tc. The thyroid and its neighboring organs receive a greater dose as thyroid uptake increases. Our comparisons also revealed an underestimation of organ doses reported for the stylized phantoms compared with the values based on the ICRP voxel phantoms in the uptake range of 5-55%, and an overestimation of absorbed dose by up to 2-fold for Iodine administration using blocking agent and for (99m)Tc incorporation.

  12. SU-E-T-38: A Head to Head Comparison of Two Commercial Phantoms Used for SRS QA

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, V; Huang, L; Huang, Y; Szegedi, M; Rassiah-Szegedi, P; Zhao, H; Salter, B [University of Utah Huntsman Cancer Institute, Salt Lake City, UT (United States)

    2015-06-15

    Purpose: To compare and contrast two commercial SRS QA phantoms. Methods: Both phantoms were evaluated in terms of their ease of setup as well as the time required to switch inserts for different tests. They were both used to evaluate the coincidence of the radiation and laser isocenters of a linear accelerator. End-to-end dosimetric tests were also performed using both ion chambers and films along two planes through the center of the phantoms. Since one phantom allows for multiple ion chamber orientations, a test was also performed to determine the effect of having the chamber oriented along the radiation beam axis’. Results: Changing inserts took 2 minutes on average for one phantom compared to 5 minutes for the other. The laser/radiation isocenter coincidence as determined from each phantom showed a maximum difference of 0.2mm. Ion chamber results were within 0.5% of the expected values when the chamber was perpendicular to the beams but measured a 3% underdose when the chamber was along the beam direction. Gamma (2%,2mm) pass rates of corresponding films were within 1% between phantoms. Conclusion: The results of the corresponding tests run on both phantoms were comparable, showing that the phantoms were equivalent for the subset of SRS QA tests run here. However, the under dose observed when the chamber was parallel to the beam direction suggests that this configuration should be avoided.

  13. Dose estimations for Iranian 11-year-old pediatric phantoms undergoing computed tomography examinations

    Science.gov (United States)

    Akhlaghi, Parisa; Miri-Hakimabad, Hashem; Rafat-Motavalli, Laleh

    2015-01-01

    In order to establish an organ and effective dose database for Iranian children undergoing computed tomography (CT) examinations, in the first step, two Iranian 11-year-old phantoms were constructed from image series obtained from CT and magnetic resonance imaging (MRI). Organ and effective doses for these phantoms were calculated for head, chest, abdomen–pelvis and chest–abdomen–pelvis (CAP) scans at tube voltages of 80, 100 and 120 kVp, and then they were compared with those of the University of Florida (UF) 11-year-old male phantom. Depth distributions of the organs and the mass of the surrounding tissues located in the beam path, which shield the internal organs, were determined for all phantoms. From the results, it was determined that the main organs of the UF phantom receive smaller doses than the two Iranian phantoms, except for the urinary bladder of the Iranian girl phantom. In addition, the relationship between the anatomical differences and the size of the dose delivered was also investigated and the discrepancies between the results were examined and justified. PMID:25972393

  14. Radiopaque Three-dimensional Printing: A Method to Create Realistic CT Phantoms.

    Science.gov (United States)

    Jahnke, Paul; Limberg, Felix R P; Gerbl, Andreas; Ardila Pardo, Gracia L; Braun, Victor P B; Hamm, Bernd; Scheel, Michael

    2017-02-01

    Purpose To develop a method to create anthropomorphic phantoms of individual patients with high precision of anatomic details and radiation attenuation properties. Materials and Methods Inkjet cartridges were filled with potassium iodide solutions (600 mg/mL) and prints were realized on plain paper (80 g/m2). Stacks of 100 prints resulted in three-dimensional phantoms of 1 cm thickness. In a first step, reproduction of patient anatomy was tested by printing computed tomographic (CT) images of a real patient abdomen scan. In a second step, gray scales, iodine deposition, and Hounsfield units were investigated by printing geometric phantoms with gray scales ranging from 0% (white) to 100% (black). On the basis of these results, a gray-scale-correction procedure was developed to achieve realistic Hounsfield units in the patient phantom. In a third step, reproduction of the real patient's Hounsfield units was verified by printing the initial patient CT scan again after application of the gray-scale-correction procedure. Data were analyzed by using Pearson correlation, linear regression, and nonlinear regression. Results The first abdomen phantom showed a detailed reproduction of the patient anatomy and demonstrated feasibility of the concept. However, individual-organ Hounsfield units deviated from the real patient CT scan. Analysis of the geometric phantoms revealed an exponential correlation between template gray scales and printer deposition. Application of a correction procedure to the template gray scales allowed for a linear correlation (r = 0.9946; 95% confidence interval: 0.9916, 0.9966). After the same correction procedure was applied to the abdomen phantom, linear correlation of phantom and patient Hounsfield units was confirmed (r = 0.9925; 95% confidence interval: 0.9635, 0.9985). Conclusion The method presented in this work can realize realistic and customizable phantoms for diagnostic and therapeutic radiology, including the reproduction of individual

  15. Development of a High Resolution Voxelised Head Phantom for Medical Physics Applications

    Science.gov (United States)

    Giacometti, V.; Guatelli, S.; Bazalova-Carter, M.; Rosenfeld, A. B.; Schulte, R. W.

    2017-01-01

    Computational anthropomorphic phantoms have become an important investigation tool for medical imaging and dosimetry for radiotherapy and radiation protection. The development of computational phantoms with realistic anatomical features contribute significantly to the development of novel methods in medical physics. For many applications, it is desirable that such computational phantoms have a real-world physical counterpart in order to verify the obtained results. In this work, we report the development of a voxelised phantom, the HIGH_RES_HEAD, modelling a paediatric head based on the commercial phantom 715-HN (CIRS). HIGH_RES_HEAD is unique for its anatomical details and high spatial resolution (0.18 × 0.18 mm2 pixel size). The development of such a phantom was required to investigate the performance of a new proton computed tomography (pCT) system, in terms of detector technology and image reconstruction algorithms. The HIGH_RES_HEAD was used in an ad-hoc Geant4 simulation modelling the pCT system. The simulation application was previously validated with respect to experimental results. When compared to a standard spatial resolution voxelised phantom of the same paediatric head, it was shown that in pCT reconstruction studies, the use of the HIGH_RES_HEAD translates into a reduction from 2% to 0.7% of the average relative stopping power difference between experimental and simulated results thus improving the overall quality of the head phantom simulation. The HIGH_RES_HEAD can also be used for other medical physics applications such as treatment planning studies. A second version of the voxelised phantom was created that contains a prototypic base of skull tumour and surrounding organs at risk. PMID:28108101

  16. Simulation of a Quality Control Jaszczak Phantom with SIMIND Monte Carlo and Adding the Phantom as an Accessory to the Program

    Directory of Open Access Journals (Sweden)

    Jalil Pirayesh Islamian

    2012-03-01

    Full Text Available Introduction Quality control is an important phenomenon in nuclear medicine imaging. A Jaszczak SPECT Phantom provides consistent performance information for any SPECT or PET system. This article describes the simulation of a Jaszczak phantom and creating an executable phantom file for comparing assessment of SPECT cameras using SIMIND Monte Carlo simulation program which is well-established for SPECT. Materials and Methods The simulation was based on a Deluxe model of Jaszczak Phantom with defined geometry. Quality control tests were provided together with initial imaging example and suggested use for the assessment of parameters such as spatial resolution, limits of lesion detection, and contrast comparing with a Siemens E.Cam SPECT system. Results The phantom simulation was verified by matching tomographic spatial resolution, image contrast, and also uniformity compared with the experiment SPECT of the phantom from filtered backprojection reconstructed images of the spheres and rods. The calculated contrasts of the rods were 0.774, 0.627, 0.575, 0.372, 0.191, and 0.132 for an experiment with the rods diameters of 31.8, 25.4, 19.1, 15.9, 12.7, and 9.5 mm, respectively. The calculated contrasts of simulated rods were 0.661, 0.527, 0.487, 0.400, 0.23, and 0.2 for cold rods and also 0.92, 0.91, 0.88, 0.81, 0.76, and 0.56 for hot rods. Reconstructed spatial tomographic resolution of both experiment and simulated SPECTs of the phantom obtained about 9.5 mm. An executable phantom file and an input phantom file were created for the SIMIND Monte Carlo program. Conclusion This phantom may be used for simulated SPECT systems and would be ideal for verification of the simulated systems with real ones by comparing the results of quality control and image evaluation. It is also envisaged that this phantom could be used with a range of radionuclide doses in simulation situations such as cold, hot, and background uptakes for the assessment of detection

  17. Corridor use by Asian elephants.

    Science.gov (United States)

    Pan, Wenjing; Lin, Liu; Luo, Aidong; Zhang, Li

    2009-06-01

    There are 18 km of Kunming-Bangkok Highway passing through the Mengyang Nature Reserve of Xishuangbanna National Nature Reserve in Yunnan Province, China. From September 2005 to September 2006 the impact of this highway on movement of wild Asian elephants between the eastern and western part of the nature reserve was studied using track transecting, rural surveys and direct monitoring. Our results showed that the number of crossroad corridors used by Asian elephants diminished from 28 to 23 following the construction of the highway. In some areas, the elephant activity diminished or even disappeared, which indicated a change in their home ranges. The utilization rate of artificial corridors was 44%. We also found that elephants preferred artificial corridors that were placed along their original corridors. During the research, wild elephants revealed their adaptation to the highway. They were found walking across the highway road surface many times and for different reasons. We suggest that the highway management bureau should revise their management strategies to mitigate the potential risks caused by elephants on the road for the safety of the public and to protect this endangered species from harm. It is also very important to protect and maintain current Asian elephants corridors in this region. © 2009 ISZS, Blackwell Publishing and IOZ/CAS.

  18. Can neural blocks prevent phantom limb pain?

    Science.gov (United States)

    Borghi, Battista; D'Addabbo, Marco; Borghi, Raffaele

    2014-07-01

    Phantom limb syndrome (PLS) is a syndrome including stump pain, phantom limb pain and not-painful phantom sensations, which involves a large part of amputee patients and often has devastating effects on their quality of life. The efficacy of standard therapies is very poor. Nerve blocks have been investigated for the treatment and prevention of PLS. Epidural and peripheral blocks limited to the first three postamputation days can only reduce acute pain but cannot prevent the later development of PLS. Recent studies have shown that ambulatory prolonged peripheral nerve block (up to 30 days postamputation) may represent a new possible option to treat phantom pain and prevent the development of PLS and chronic pain.

  19. Phantom perception: voluntary and involuntary nonretinal vision.

    Science.gov (United States)

    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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Prevalence of Phantom Limb Pain, Stump Pain, and Phantom Limb Sensation among the Amputated Cancer Patients in India: A Prospective, Observational Study.

    Science.gov (United States)

    Ahmed, Arif; Bhatnagar, Sushma; Mishra, Seema; Khurana, Deepa; Joshi, Saurabh; Ahmad, Syed Mehmood

    2017-01-01

    The phantom limb pain (PLP) and phantom limb sensation (PLS) are very common among amputated cancer patients, and they lead to considerable morbidity. In spite of this, there is a lack of epidemiological data of this phenomenon among the Asian population. This study was done to provide the data from Indian population. The prevalence of PLP, stump pain (SP), and PLS was prospectively analyzed from the amputated cancer patients over a period of 2 years in Dr. B.R.A. Institute Rotary Cancer Hospital, All India Institute of Medical Sciences, New Delhi. The risk factors and the impact of phantom phenomenon on patients were also noted. The prevalence of PLP was 41% at 3 and 12 months and 45.3% at 6 months, whereas that of SP and PLS was 14.4% and 71.2% at 3 months, 18.75% and 37.1% at 6 months, 15.8% and 32.4% at 12 months, respectively. There was higher prevalence of PLP and PLS among the patients with history of preamputation pain, smoking with proximal level of amputation, receiving general anesthesia, receiving intravenous (IV) opioid postoperative analgesia, and developing neuroma or infection. The prevalence of PLP and PLS was higher among the cancer amputees as compared to SP, and a few risk factors responsible for their higher prevalence were found in our study. The PLP and PLS lead to considerable morbidity in terms of sleep disturbance and depression.

  1. Induced sensorimotor brain plasticity controls pain in phantom limb patients

    OpenAIRE

    Yanagisawa, Takufumi; Fukuma, Ryohei; Seymour, Ben; Hosomi, Koichi; Kishima, Haruhiko; Shimizu, Takeshi; Yokoi, Hiroshi; Hirata, Masayuki; Yoshimine, Toshiki; Kamitani, Yukiyasu; Saitoh, Youichi

    2016-01-01

    The cause of pain in a phantom limb after partial or complete deafferentation is an important problem. A popular but increasingly controversial theory is that it results from maladaptive reorganization of the sensorimotor cortex, suggesting that experimental induction of further reorganization should affect the pain, especially if it results in functional restoration. Here we use a brain-machine interface (BMI) based on real-time magnetoencephalography signals to reconstruct affected hand mov...

  2. Pharmacologic interventions for treating phantom limb pain.

    Science.gov (United States)

    Alviar, Maria Jenelyn M; Hale, Tom; Dungca, Monalisa

    2016-10-14

    This is an updated version of the original Cochrane review published in Issue 12, 2011. Phantom limb pain (PLP) is pain that arises in the missing limb after amputation and can be severe, intractable, and disabling. Various medications have been studied in the treatment of phantom pain. There is currently uncertainty in the optimal pharmacologic management of PLP. This review aimed to summarise the evidence of effectiveness of pharmacologic interventions in treating PLP. For this update, we searched the Cochrane Central Register of Controlled Trials (CENTRAL, the Cochrane Library), MEDLINE, and Embase for relevant studies. We ran the searches for the original review in September 2011 and subsequent searches for this update up to April 2016. We sought additional studies from clinical trials databases and reference lists of retrieved papers. We included randomised and quasi-randomised trials studying the effectiveness of pharmacologic interventions compared with placebo, another active treatment, or no treatment, in established PLP. We considered the following outcomes: change in pain intensity, function, sleep, depression or mood, quality of life, adverse events, treatment satisfaction, and withdrawals from the study. We independently assessed issues of study quality and extracted efficacy and adverse event data. Due to the wide variability in the studies, we did not perform a meta-analysis for all the interventions and outcomes, but attempted to pool the results of some studies where possible. We prepared a qualitative description and narrative summary of results. We assessed clinical heterogeneity by making qualitative comparisons of the populations, interventions, outcomes/outcome measures, and methods. We added only one new study with 14 participants to this updated review. We included a 14 studies (10 with low risk of bias and 4 with unclear risk of bias overall) with a total of 269 participants. We added another drug class, botulinum neurotoxins (BoNTs), in

  3. The effect of phantom parent groups on genetic trend estimation ...

    African Journals Online (AJOL)

    Bias in the estimation of trend was reduced when phantom parent groups were taken into account. The 109 385 base animals were replaced by 64 phantom parent groups. Phantom parent groups were constructed by combining year of birth, country of birth and selection intensity of the phantom parents. In recent years ...

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

    Science.gov (United States)

    Kiarashi, Nooshin; Nolte, Adam C; Sturgeon, Gregory M; Segars, William P; Ghate, Sujata V; Nolte, Loren W; Samei, Ehsan; Lo, Joseph Y

    2015-07-01

    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. 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. 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-law descriptions of the phantom images

  5. Acupuncture treatment of phantom limb pain and phantom limb sensation in a primary care setting.

    Science.gov (United States)

    Davies, Arwel

    2013-03-01

    A 45-year-old man presented with phantom limb pain and phantom limb sensation 12 weeks after an above-elbow amputation of his right arm. He underwent seven sessions of acupuncture at weekly intervals carried out by his general practitioner on his intact left arm, with complete relief of the phantom limb pain and considerable improvement of the phantom limb sensation of his right arm. This case demonstrates the possible benefits from the use of short acupuncture sessions for a potentially chronic condition undertaken within the constraints of a busy general medical practice.

  6. An Alternative Method of Evaluating 1540NM Exposure Laser Damage using an Optical Tissue Phantom

    National Research Council Canada - National Science Library

    Jindra, Nichole M; Figueroa, Manuel A; Rockwell, Benjamin A; Chavey, Lucas J; Zohner, Justin J

    2006-01-01

    An optical phantom was designed to physically and optically resemble human tissue, in an effort to provide an alternative for detecting visual damage resulting from inadvertent exposure to infrared lasers...

  7. Mirror Therapy for Phantom Limb Pain

    OpenAIRE

    Kim, Sae Young; Kim, Yun Young

    2012-01-01

    Phantom limb pain is a painful sensation that is perceived in a body part that no longer exists. To control this pain, many methods have been used such as medication, physical treatment, nerve block, neuromodulation, surgical treatment and mirror therapy. However, until now, there effects have been uncertain. We report the successful reduction of phantom limb pain using mirror therapy when other treatments initially failed to control the pain.

  8. Cyclic universe due to phantom and quintessence

    OpenAIRE

    Gao, Changjun; Lu, Youjun; Shen, You-Gen

    2014-01-01

    We explore a cyclic universe due to phantom and quintessence fields. We find that, in every cycle of the evolution of the universe, the phantom dominates the cosmic early history and quintessence dominates the cosmic far future. In this model of universe, there are infinite cycles of expansion and contraction. Different from the inflationary universe, the corresponding cosmic space-time is geodesically complete and quantum stable. But similar to the Cyclic Model, the flatness problem, the hor...

  9. The menacing phantom: what pulls the trigger?

    Science.gov (United States)

    Giummarra, Melita J; Georgiou-Karistianis, Nellie; Nicholls, Michael E R; Gibson, Stephen J; Chou, Michael; Bradshaw, John L

    2011-08-01

    Phantom phenomena are frequent following amputation, but how this often painful experience is modified or triggered by spontaneous events or sensations often puzzles amputees and clinicians alike. We explored triggers of phantom phenomena in a heterogeneous sample of 264 upper and lower limb adult amputees with phantom sensations. Participants completed a structured questionnaire to determine the prevalence and nature of the triggers of phantom phenomena. The four categories of triggers identified include: (a) a quarter of participants experiencing psychological, emotional or autonomic triggers; (b) half experiencing behavioral triggers, "forgetting" the limb's absence and attempting to use the phantom; (c) one-fifth experiencing weather-induced triggers; and (d) one-third experiencing sensations referred from parts of the body. Upper limb amputees; and were more likely to experience weather-induced phantom phenomena than lower limb amputees; and upper and lower limb amputees were equally likely to experience referred sensations from the genitals, contradicting the homuncular remapping hypothesis. Traumatic amputees were more likely to report emotional triggers. Further, while those with emotional triggers exhibited poorer acceptance of the limitations of amputation, they were more likely to employ adaptive coping mechanisms. Finally, habitual "forgetting" behaviors were most common soon after amputation, whereas other more adaptive schemata (e.g., self-defense) were equally likely to be performed at any time following amputation. Various likely inter-related mechanisms are discussed in relation to phantom triggers. Ultimately, optimizing stump and neuroma management, as well as restoring function of central networks for pain, limb movement, and amputation-related memories, should help manage spontaneously triggered phantom phenomena. Copyright © 2011 European Federation of International Association for the Study of Pain Chapters. All rights reserved.

  10. Abundance and Community Structure of Bacteria on Asian Dust Particles Collected in Beijing, China, during the Asian Dust Season.

    Science.gov (United States)

    Yamaguchi, Nobuyasu; Baba, Takashi; Ichijo, Tomoaki; Himezawa, Yuka; Enoki, Kanami; Saraya, Makoto; Li, Pin-Fang; Nasu, Masao

    2016-01-01

    Approximately 180 t/km(2) of Asian dust particles are estimated to fall annually on Beijing, China, and there is significant concern about the influence of microbes transported by Asian dust events on human health and downwind ecosystems. In this study, we collected Asian dust particles in Beijing, and analyzed the bacterial communities on these particles by culture-independent methods. Bacterial cells on Asian dust particles were visualized first by laser scanning microscopy, which demonstrated that Asian dust particles carry bacterial cells to Beijing. Bacterial abundance, as determined by quantitative polymerase chain reaction (PCR), was 10(8) to 10(9) cells/g, a value about 10 times higher than that in Asian dust source soils. Inter-seasonal variability of bacterial community structures among Asian dust samples, as compared by terminal restriction fragment length polymorphism (T-RFLP), was low during the Asian dust season. Several viable bacteria, including intestinal bacteria, were found in Asian dust samples by denaturing gradient gel electrophoresis (DGGE). Clone library analysis targeting 16S ribosomal RNA (rRNA) gene sequences demonstrated that bacterial phylogenetic diversity was high in the dust samples, and most of these were environmental bacteria distributed in soil and air. The dominant species in the clone library was Segetibacter aerophilus (Bacteroidetes), which was first isolated from an Asian dust sample collected in Korea. Our results also indicate the possibility of a change in the bacterial community structure during transportation and increases in desiccation-tolerant bacteria such as Firmicutes.

  11. Low cost phantom for computed radiology; Objeto de teste de baixo custo para radiologia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Travassos, Paulo Cesar B.; Magalhaes, Luis Alexandre G., E-mail: pctravassos@ufrj.br [Universidade do Estado do Rio de Janeiro (IBRGA/UERJ), RJ (Brazil). Laboratorio de Ciencias Radiologicas; Augusto, Fernando M.; Sant' Yves, Thalis L.A.; Goncalves, Elicardo A.S. [Instituto Nacional de Cancer (INCA), Rio de Janeiro, RJ (Brazil); Botelho, Marina A. [Hospital Universitario Pedro Ernesto (UERJ), Rio de Janeiro, RJ (Brazil)

    2012-08-15

    This article presents the results obtained from a low cost phantom, used to analyze Computed Radiology (CR) equipment. The phantom was constructed to test a few parameters related to image quality, as described in [1-9]. Materials which can be easily purchased were used in the construction of the phantom, with total cost of approximately U$100.00. A bar pattern was placed only to verify the efficacy of the grids in the spatial resolution determination, and was not included in the budget because the data was acquired from the grids. (author)

  12. Internal strain estimation for quantification of human heel pad elastic modulus: A phantom study

    DEFF Research Database (Denmark)

    Holst, Karen; Liebgott, Hervé; Wilhjelm, Jens E.

    2013-01-01

    heel phantoms were manufactured featuring a combination of three heel pad stiffnesses and three heel pad thicknesses to model the normal human variation. Each phantom was tested in an indentation system comprising a 7MHz linear array ultrasound transducer, working as the indentor, and a connected load....... Elastic moduli were found from the resulting stress–strain curves. The elastic moduli made it possible to distinguish eight of nine phantoms from each other according to the manufactured stiffness and showed very little dependence of the thickness. Mean elastic moduli for the three soft, the three medium...

  13. Development of a New Cardiac and Torso Phantom for Verifying the Accuracy of Myocardial Perfusion SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto; Tomoaki [Dept. of Radiological Science, School of Health Science, International University of Health and Welfare, Otawara(Japan); Kim, Jung Min; Lee, Ki Sung [Dept. of Radiological Science, College of Health Science, Korea University, Seoul (Korea, Republic of); Takayama, Teruhiko [Dept. of Clinical Laboratory Science, Graduate School of Medicine, Kanazawa University, Kanazawa (Japan); Kitashi, Kitahara [Dept. of Radiology, Fujigaoka Hospital, Showa University, Tokyo (Korea, Republic of)

    2008-12-15

    Corrections of attenuation, scatter and resolution are important in order to improve the accuracy of single photon emission computed tomography (SPECT) image reconstruction. Especially, the heart movement by respiration and beating cause the errors in the corrections. Myocardial phantom is used to verify the correction methods, but there are many different parts in the current phantoms in actual human body. Therefore the results using a phantom are often considered apart from the clinical data. We developed a new phantom that implements the human body structure around the thorax more faithfully. The new phantom has the small mediastinum which can simulate the structure in which the lung adjoins anterior, lateral and apex of myocardium. The container was made of acrylic and water-equivalent material was used for mediastinum. In addition, solidified polyurethane foam in epoxy resin was used for lung. Five different sizes of myocardium were developed for the quantitative gated SPECT (QGS). The septa of all different cardiac phantoms were designed so that they can be located at the same position. The proposed phantom was attached with liver and gallbladder, the adjustment was respectively possible for the height of them. The volumes of five cardiac ventricles were 150.0, 137.3, 83.1, 42.7 and 38.6 ml respectively. The SPECT were performed for the new phantom, and the differences between the images were examined after the correction methods were applied. The three-dimensional tomography of myocardium was well reconstructed, and the subjective evaluations were done to show the difference among the various corrections. We developed the new cardiac and torso phantom, and the difference of various corrections was shown on SPECT images and QGS results.

  14. Phantom pain reduction by low-frequency and low-intensity electromagnetic fields.

    Science.gov (United States)

    Bókkon, István; Till, Attila; Grass, Friedrich; Erdöfi Szabó, Attila

    2011-09-01

    Although various treatments have been presented for phantom pain, there is little proof supporting the benefits of pharmacological treatments, surgery or interventional techniques, electroconvulsive therapy, electrical nerve stimulation, far infrared ray therapy, psychological therapies, etc. Here, we report the preliminary results for phantom pain reduction by low-frequency and intensity electromagnetic fields under clinical circumstances. Our method is called as Electromagnetic-Own-Signal-Treatment (EMOST). Fifteen people with phantom limb pain participated. The patients were treated using a pre-programmed, six sessions. Pain intensity was quantified upon admission using a 0-10 verbal numerical rating scale. Most of the patients (n = 10) reported a marked reduction in the intensity of phantom limb pain. Several patients also reported about improvement in their sleep and mood quality, or a reduction in the frequency of phantom pain after the treatments. No improvements in the reduction of phantom limb pain or sleep and mood improvement were reported in the control group (n = 5). Our nonlinear electromagnetic EMOST method may be a possible therapeutic application in the reduction of phantom limb pain. Here, we also suggest that some of the possible effects of the EMOST may be achieved via the redox balance of the body and redox-related neural plasticity.

  15. Thin-film resistance temperature detector array for the measurement of temperature distribution inside a phantom

    Science.gov (United States)

    Sim, Jai Kyoung; Hyun, Jaeyub; Doh, Il; Ahn, Bongyoung; Kim, Yong Tae

    2018-02-01

    A thin-film resistance temperature detector (RTD) array is proposed to measure the temperature distribution inside a phantom. HIFU (high-intensity focused ultrasound) is a non-invasive treatment method using focused ultrasound to heat up a localized region, so it is important to measure the temperature distribution without affecting the ultrasonic field and heat conduction. The present 25 µm thick PI (polyimide) film is transparent not only to an ultrasonic field, because its thickness is much smaller than the wavelength of ultrasound, but also to heat conduction, owing to its negligible thermal mass compared to the phantom. A total of 33 RTDs consisting of Pt resistors and interconnection lines were patterned on a PI substrate using MEMS (microelectromechanical systems) technology, and a polymer phantom was fabricated with the film at the center. The expanded uncertainty of the RTDs was 0.8 K. In the experimental study using a 1 MHz HIFU transducer, the maximum temperature inside the phantom was measured as 70.1 °C just after a HIFU excitation of 6.4 W for 180 s. The time responses of the RTDs at different positions also showed the residual heat transfer inside the phantom after HIFU excitation. HIFU results with the phantom showed that a thin-film RTD array can measure the temperature distribution inside a phantom.

  16. The impact of calibration phantom errors on dual-energy digital mammography

    Science.gov (United States)

    Mou, Xuanqin; Chen, Xi; Sun, Lijun; Yu, Hengyong; Ji, Zhen; Zhang, Lei

    2008-11-01

    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.

  17. The impact of calibration phantom errors on dual-energy digital mammography

    Energy Technology Data Exchange (ETDEWEB)

    Mou Xuanqin; Chen Xi [Institute of Image Processing and Pattern Recognition, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China); Sun Lijun [Department of Radiology, Xijing Hospital, Fourth Military Medical University, Xi' an, Shaanxi 710032 (China); Yu Hengyong [Biomedical Imaging Division, VT-WFU School of Biomedical Engineering and Science, Virginia Tech., Blacksburg, VA 240601 (United States); Ji Zhen [Department of Information Engineering, Shenzhen University, Shenzhen 518060 (China); Zhang Lei [Department of Computing, Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong)], E-mail: xqmou@mail.xjtu.edu.cn

    2008-11-21

    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.

  18. The GSF family of voxel phantoms.

    Science.gov (United States)

    Petoussi-Henss, Nina; Zanki, Maria; Fill, Ute; Regulla, Dieter

    2002-01-07

    Voxel phantoms are human models based on computed tomographic or magnetic resonance images obtained from high-resolution scans of a single individual. They consist of a huge number of volume elements (voxels) and are at the moment the most precise representation of the human anatomy. The purpose of this paper is to introduce the GSF voxel phantoms, with emphasis on the new ones and highlight their characteristics and limitations. The GSF voxel family includes at the moment two paediatric and five adult phantoms of both sexes, different ages and stature and several others are under construction. Two phantoms made of physical calibration phantoms are also available to be used for validation purposes. The GSF voxel phantoms tend to cover persons of individual anatomy and were developed to be used for numerical dosimetry of radiation transport but other applications are also possible. Examples of applications in patient dosimetry in diagnostic radiology and in nuclear medicine as well as for whole-body irradiations from idealized external exposures are given and discussed.

  19. The GSF family of voxel phantoms

    Science.gov (United States)

    Petoussi-Henss, Nina; Zankl, Maria; Fill, Ute; Regulla, Dieter

    2002-01-01

    Voxel phantoms are human models based on computed tomographic or magnetic resonance images obtained from high-resolution scans of a single individual. They consist of a huge number of volume elements (voxels) and are at the moment the most precise representation of the human anatomy. The purpose of this paper is to introduce the GSF voxel phantoms, with emphasis on the new ones and highlight their characteristics and limitations. The GSF voxel family includes at the moment two paediatric and five adult phantoms of both sexes, different ages and stature and several others are under construction. Two phantoms made of physical calibration phantoms are also available to be used for validation purposes. The GSF voxel phantoms tend to cover persons of individual anatomy and were developed to be used for numerical dosimetry of radiation transport but other applications are also possible. Examples of applications in patient dosimetry in diagnostic radiology and in nuclear medicine as well as for whole-body irradiations from idealized external exposures are given and discussed.

  20. SU-E-T-114: Analysis of MLC Errors On Gamma Pass Rates for Patient-Specific and Conventional Phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Sterling, D; Ehler, E [University of Minnesota, Minneapolis, MN (United States)

    2015-06-15

    Purpose: To evaluate whether a 3D patient-specific phantom is better able to detect known MLC errors in a clinically delivered treatment plan than conventional phantoms. 3D printing may make fabrication of such phantoms feasible. Methods: Two types of MLC errors were introduced into a clinically delivered, non-coplanar IMRT, partial brain treatment plan. First, uniformly distributed random errors of up to 3mm, 2mm, and 1mm were introduced into the MLC positions for each field. Second, systematic MLC-bank position errors of 5mm, 3.5mm, and 2mm due to simulated effects of gantry and MLC sag were introduced. The original plan was recalculated with these errors on the original CT dataset as well as cylindrical and planar IMRT QA phantoms. The original dataset was considered to be a perfect 3D patient-specific phantom. The phantoms were considered to be ideal 3D dosimetry systems with no resolution limitations. Results: Passing rates for Gamma Index (3%/3mm and no dose threshold) were calculated on the 3D phantom, cylindrical phantom, and both on a composite and field-by-field basis for the planar phantom. Pass rates for 5mm systematic and 3mm random error were 86.0%, 89.6%, 98% and 98.3% respectively. For 3.5mm systematic and 2mm random error the pass rates were 94.7%, 96.2%, 99.2% and 99.2% respectively. For 2mm systematic error with 1mm random error the pass rates were 99.9%, 100%, 100% and 100% respectively. Conclusion: A 3D phantom with the patient anatomy is able to discern errors, both severe and subtle, that are not seen using conventional phantoms. Therefore, 3D phantoms may be beneficial for commissioning new treatment machines and modalities, patient-specific QA and end-to-end testing.

  1. WE-F-16A-06: Using 3D Printers to Create Complex Phantoms for Dose Verification, Quality Assurance, and Treatment Planning System Commissioning in Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Kassaee, A; Ding, X; McDonough, J; Reiche, M; Witztum, A; Teo, B [University Pennsylvania, Philadelphia, PA (United States)

    2014-06-15

    Purpose: To use 3D printers to design and construct complex geometrical phantoms for commissioning treatment planning systems, dose calculation algorithms, quality assurance (QA), dose delivery, and patient dose verifications. Methods: In radiotherapy, complex geometrical phantoms are often required for dose verification, dose delivery and calculation algorithm validation. Presently, fabrication of customized phantoms is limited due to time, expense and challenges in machining of complex shapes. In this work, we designed and utilized 3D printers to fabricate two phantoms for QA purposes. One phantom includes hills and valleys (HV) for verification of intensity modulated radiotherapy for photons, and protons (IMRT and IMPT). The other phantom includes cylindrical cavities (CC) of various sizes for dose verification of inhomogeneities. We evaluated the HV phantoms for an IMPT beam, and the CC phantom to study various inhomogeneity configurations using photon, electron, and proton beams. Gafcromic ™ films were used to quantify the dose distributions delivered to the phantoms. Results: The HV phantom has dimensions of 12 cm × 12 cm and consists of one row and one column of five peaks with heights ranging from 2 to 5 cm. The CC phantom has a size 10 cm × 14 cm and includes 6 cylindrical cavities with length of 7.2 cm and diameters ranging from 0.6 to 1.2 cm. The IMPT evaluation using the HV phantom shows good agreement as compared to the dose distribution calculated with treatment planning system. The CC phantom also shows reasonable agreements for using different algorithms for each beam modalities. Conclusion: 3D printers with submillimiter resolutions are capable of printing complex phantoms for dose verification and QA in radiotherapy. As printing costs decrease and the technology becomes widely available, phantom design and construction will be readily available to any clinic for testing geometries that were not previously feasible.

  2. SU-E-T-124: Anthropomorphic Phantoms for Confirmation of Linear Accelerator Based Small Animal Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Perks, J; Benedict, S [UC Davis Cancer Center, Sacramento, CA (United States); Lucero, S [UC Davis, Davis, CA (United States)

    2015-06-15

    Purpose: To document the support of radiobiological small animal research by a modern radiation oncology facility. This study confirms that a standard, human use linear accelerator can cover the range of experiments called for by researchers performing animal irradiation. A number of representative, anthropomorphic murine phantoms were made. The phantoms confirmed the small field photon and electron beams dosimetry validated the use of the linear accelerator for rodents. Methods: Laser scanning a model, CAD design and 3D printing produced the phantoms. The phantoms were weighed and CT scanned to judge their compatibility to real animals. Phantoms were produced to specifically mimic lung, gut, brain, and othotopic lesion irradiations. Each phantom was irradiated with the same protocol as prescribed to the live animals. Delivered dose was measured with small field ion chambers, MOS/FETs or TLDs. Results: The density of the phantom material compared to density range across the real mice showed that the printed material would yield sufficiently accurate measurements when irradiated. The whole body, lung and gut irradiations were measured within 2% of prescribed doses with A1SL ion chamber. MOSFET measurements of electron irradiations for the orthotopic lesions allowed refinement of the measured small field output factor to better than 2% and validated the immunology experiment of irradiating one lesion and sparing another. Conclusion: Linacs are still useful tools in small animal bio-radiation research. This work demonstrated a strong role for the clinical accelerator in small animal research, facilitating standard whole body dosing as well as conformal treatments down to 1cm field. The accuracy of measured dose, was always within 5%. The electron irradiations of the phantom brain and flank tumors needed adjustment; the anthropomorphic phantoms allowed refinement of the initial output factor measurements for these fields which were made in a large block of solid water.

  3. Mental Health and Asian Americans

    Science.gov (United States)

    ... Data > Minority Population Profiles > Asian American > Mental Health Mental Health and Asian Americans Suicide was the 9th leading ... Americans is half that of the White population. MENTAL HEALTH STATUS Serious psychological distress among adults 18 years ...

  4. Calculations of S values and effective dose for the radioiodine carrier and surrounding individuals based on Chinese hybrid reference phantoms using the Monte Carlo technique.

    Science.gov (United States)

    Geng, Changran; Tang, Xiaobin; Qian, Wei; Guan, Fada; Johns, Jesse; Yu, Haiyan; Gong, Chunhui; Shu, Diyun; Chen, Da

    2015-09-01

    The S values for the thyroid as the radioiodine source organ to other target organs were investigated using Chinese hybrid reference phantoms and the Monte Carlo code MCNP5. Two radioiodine isotopes (125)I and (131)I uniformly distributed in the thyroid were investigated separately. We compared our S values for (131)I in Chinese phantoms with previous studies using other types of phantoms: Oak Ridge National Laboratory (ORNL) stylized phantoms, International Commission on Radiological Protection (ICRP) voxel phantoms, and University of Florida (UF) phantoms. Our results are much closer to the UF phantoms. For each specific target organ, the S value for (131)I is larger than for (125)I in both male and female phantoms. In addition, the S values and effective dose to surrounding face-to-face exposed individuals, including different genders and ages (10- and 15-year-old juniors, and adults) from an adult male radioiodine carrier were also investigated. The target organ S values and effective dose for surrounding individuals obey the inverse square law with the distance between source and target phantoms. The obtained effective dose data in Chinese phantoms are comparable to the results in a previous study using the UF phantoms. The data generated in this study can serve as the reference to make recommendations for radiation protection of the Chinese patients or nuclear workers.

  5. Educational inequalities and success in Asian countries in PISA 2009

    Directory of Open Access Journals (Sweden)

    Alba Castejón Company

    2011-09-01

    Full Text Available This article discusses the results of PISA 2009 from seven Asian countries. The analysis focuses on three hubs of educational inequality: academic inequalities, inequalities by gender and social in- equalities. The main conclusion drawn from the results of this work is that is not possible to affirm that Asian education systems constitute a homogeneous educational model.

  6. Anthropomorphic phantom to investigate the bladder dose in gynecological high-dose-rate brachytherapy.

    Science.gov (United States)

    Silva, R M V; Belinato, W; Macedo, L E; Souza, D N

    2015-01-01

    This study presents a prototype of a phantom appropriate for experimental bladder dosimetry. This work presents details of the phantom construction and dosimetric results obtained using radiochromic film and optically stimulated luminescence dosimeters (OSLDs). The phantom was constructed of polymethyl methacrylate. Two artificial bladders were three-dimensional printed using previous computed tomography images. Radiochromic films and OSLDs were positioned on the artificial bladder walls, and the applicators were placed according to the original computed tomography image. The prototype phantom simulated the behavior of the dose on the bladder surface, enabling bladder movement in all directions. The dosimetric study that was performed using radiochromic film and OSLDs exhibited concordance, in most cases, with the results obtained from the planning system. The methodology presented offers conditions for researchers to investigate more accurately the behavior of the dose on the bladder surface during intracavitary brachytherapy procedures. Copyright © 2015 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  7. Scrolling and Strolling, Asian Style

    Science.gov (United States)

    Sterling, Joan

    2012-01-01

    In this article, the author describes a lesson on Asian cultures. Asian cultures demonstrate respect for nature through their art. Students learned how to use Asian brush techniques and designs to create scrolls. They also learned how to write Haiku, a three-line form of poetry that uses a pattern of syllables.

  8. Tissue Equivalent Phantom Design for Characterization of a Coherent Scatter X-ray Imaging System

    Science.gov (United States)

    Albanese, Kathryn Elizabeth

    testing. Our imaging system has been able to define the location and composition of the various materials in the phantom. These phantoms were used to characterize the CACSSI system in terms of beam width and imaging technique. The result of this work showed accurate modeling and characterization of the phantoms through comparison of the tissue-equivalent form factors to those from literature. The physical construction of the phantoms, based on actual patient anatomy, was validated using mammography and computed tomography to visually compare the clinical images to those of actual patient anatomy.

  9. The development of a population of 4D pediatric XCAT phantoms for imaging research and optimization

    Energy Technology Data Exchange (ETDEWEB)

    Segars, W. P., E-mail: paul.segars@duke.edu; Norris, Hannah; Sturgeon, Gregory M.; Zhang, Yakun; Bond, Jason; Samei, E. [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Minhas, Anum; Frush, D. [Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Tward, Daniel J.; Ratnanather, J. T.; Miller, M. I. [Center for Imaging Science, Johns Hopkins University, Baltimore, Maryland 21218 (United States)

    2015-08-15

    Purpose: We previously developed a set of highly detailed 4D reference pediatric extended cardiac-torso (XCAT) phantoms at ages of newborn, 1, 5, 10, and 15 yr with organ and tissue masses matched to ICRP Publication 89 values. In this work, we extended this reference set to a series of 64 pediatric phantoms of varying age and height and body mass percentiles representative of the public at large. The models will provide a library of pediatric phantoms for optimizing pediatric imaging protocols. Methods: High resolution positron emission tomography-computed tomography data obtained from the Duke University database were reviewed by a practicing experienced radiologist for anatomic regularity. The CT portion of the data was then segmented with manual and semiautomatic methods to form a target model defined using nonuniform rational B-spline surfaces. A multichannel large deformation diffeomorphic metric mapping algorithm was used to calculate the transform from the best age matching pediatric XCAT reference phantom to the patient target. The transform was used to complete the target, filling in the nonsegmented structures and defining models for the cardiac and respiratory motions. The complete phantoms, consisting of thousands of structures, were then manually inspected for anatomical accuracy. The mass for each major tissue was calculated and compared to linearly interpolated ICRP values for different ages. Results: Sixty four new pediatric phantoms were created in this manner. Each model contains the same level of detail as the original XCAT reference phantoms and also includes parameterized models for the cardiac and respiratory motions. For the phantoms that were 10 yr old and younger, we included both sets of reproductive organs. This gave them the capability to simulate both male and female anatomy. With this, the population can be expanded to 92. Wide anatomical variation was clearly seen amongst the phantom models, both in organ shape and size, even for

  10. Anthropometric measurements for Asian and Caucasian elderly.

    Science.gov (United States)

    Netland, P A; Brownstein, H

    1985-02-01

    While differences in height and weight were observed, the results of this study indicate that there are similarities between Caucasian and Asian-American elderly in skin-fold measurements and prevalence of obesity. These results illustrate the value of skinfold thickness as a more accurate measure of adiposity than indexes on the basis of weight for given height. In addition, our results provide evidence for ethnic similarities in the distribution of subcutaneous fat and the prevalence of obesity in elderly Caucasians and Asian-Americans.

  11. The effects of contact with Asians and Asian Americans on White American college students: attitudes, awareness of racial discrimination, and psychological adjustment.

    Science.gov (United States)

    Dinh, Khanh T; Weinstein, Traci L; Nemon, Melissa; Rondeau, Sara

    2008-12-01

    On the basis of acculturation theory, explicating mutual influences between different cultural or ethnic groups coming into contact, this study focused "on the other side of acculturation" theory by examining the effects of intercultural contact with Asians and Asian Americans on the psychosocial experiences of White American college students. Participants (N = 315), undergraduates attending a public university located within the state of Massachusetts, completed a survey that assessed demographic and personal characteristics, acculturation (extent of intercultural contact with Asian people and Asian cultures), attitudes towards Asians and Asian Americans, awareness of institutional discrimination and blatant racial issues, and psychological distress. Results indicated that White American students' intercultural contact with Asians and Asian Americans contributed significant variance to the prediction of their attitudes towards this ethnic group and awareness of discrimination and racial issues, but not to psychological distress. This study provides implications for understanding mutual acculturative influences between different ethnic groups in the United States.

  12. Cosmological perturbations on the Phantom brane

    CERN Document Server

    Bag, Satadru; Shtanov, Yuri; Sahni, Varun

    2016-01-01

    We obtain a closed system of equations for scalar perturbations in a multi-component braneworld. Our braneworld possesses a phantom-like equation of state at late times, $w_{\\rm eff} < -1$, but no big-rip future singularity. In addition to matter and radiation, the braneworld possesses a new effective degree of freedom - the 'Weyl fluid' or 'dark radiation'. Setting initial conditions on super-Hubble spatial scales at the epoch of radiation domination, we evolve perturbations of radiation, pressureless matter and the Weyl fluid until the present epoch. We observe a gradual decrease in the amplitude of the Weyl-fluid perturbations after Hubble-radius crossing, which results in a negligible effect of the Weyl fluid on the evolution of matter perturbations on spatial scales relevant for structure formation. Consequently, the quasi-static approximation of Koyama and Maartens provides a good fit to the exact results during the matter-dominated epoch. We find that the late-time growth of density perturbations on...

  13. Asian fungal fermented food

    NARCIS (Netherlands)

    Nout, M.J.R.; Aidoo, K.E.

    2010-01-01

    In Asian countries, there is a long history of fermentation of foods and beverages. Diverse micro-organisms, including bacteria, yeasts and moulds, are used as starters, and a wide range of ingredients can be made into fermented foods. The main raw materials include cereals, leguminous seeds,

  14. HIV Among Asians

    Science.gov (United States)

    ... Prevention VIH En Español Get Tested Find an HIV testing site near you. Enter ZIP code or city Follow HIV/AIDS CDC HIV CDC HIV/AIDS See RSS | ... Email Updates on HIV Syndicated Content Website Feedback HIV Among Asians in the United States Format: Select ...

  15. Malaysian Cinema, Asian Film

    NARCIS (Netherlands)

    Heide, van der William

    2002-01-01

    This title series departs from traditional studies of national cinema by accentuating the intercultural and intertextual links between Malaysian films and Asian (as well as European and American) film practices. Using cross-cultural analysis, the author characterizes Malaysia as a pluralist society

  16. The motor cortex and its role in phantom limb phenomena.

    Science.gov (United States)

    Reilly, Karen T; Sirigu, Angela

    2008-04-01

    Limb amputation results in plasticity of connections between the brain and muscles; the cortical motor representation of the missing limb seemingly disappears. The disappearance of the hand's motor representation is, however, difficult to reconcile with evidence that a perceptual representation of the missing limb persists in the form of a phantom limb endowed with sensory and motor qualities. Here, we argue that despite considerable reorganization within the motor cortex of upper-limb amputees, the representation of the amputated hand does not disappear. We hypothesize that two levels of hand-movement representation coexist within the primary motor cortex; at one level, limb movements are specified in terms of arm and hand motor commands, and at another level, limb movements are specified as muscles synergies. We propose that primary motor cortex reorganization after amputation concerns primarily the upper limb's muscular map but not its motor command map and that the integrity of the motor command map underlies the existence of the phantom limb.

  17. Computerized evaluation of mammographic image quality using phantom images.

    Science.gov (United States)

    Dougherty, G

    1998-01-01

    A simple, quick and computerized method for quantitatively evaluating the image quality of mammography phantom images has been developed. Images of the American College of Radiology (ACR) mammographic accreditation phantoms were acquired under different X-ray techniques, scored and ranked subjectively by five expert readers, and digitized for quantitative analysis. The contrast and signal-to-noise (contrast-to-noise) ratios of the main nodule and microcalcification group were obtained accurately and reproducibly using an image processing protocol. The contrast values were successful at discriminating differences in image quality due to variations in scatter conditions (as a result of different kVp's, and the presence or absence of an acrylic scatterer and/or a moving Bucky grid). They were more precise, reproducible and sensitive than the ACR score. In particular, the contrast of the main nodule was highly correlated (r(s) = 0.988: pimage quality by our panel of expert readers.

  18. FLUKA simulation studies on in-phantom dosimetric parameters of a LINAC-based BNCT

    Science.gov (United States)

    Ghal-Eh, N.; Goudarzi, H.; Rahmani, F.

    2017-12-01

    The Monte Carlo simulation code, FLUKA version 2011.2c.5, has been used to estimate the in-phantom dosimetric parameters for use in BNCT studies. The in-phantom parameters of a typical Snyder head, which are necessary information prior to any clinical treatment, have been calculated with both FLUKA and MCNPX codes, which exhibit a promising agreement. The results confirm that FLUKA can be regarded as a good alternative for the MCNPX in BNCT dosimetry simulations.

  19. Computed tomography scan optimization using head phantom and radiochromic films

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Lorena C.; Santana, P.C.; Velasquez, Carlos E.; Mourao, Arnaldo P., E-mail: lorena.cfernandes@hotmail.com, E-mail: carlosvelcab@hotmail.com, E-mail: pridili@gmail.com, E-mail: apmourao@gmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte (Brazil). Departamento de Engenharia Nuclear; Centro de Imagem Molecular do INCT-Medicina Molecular (CIMol/UFMG) Belo Horizonte (Brazil); Centro Federal de Educação Tecnológica de Minas Gerais (CEFET-MG), Belo Horizonte (Brazil)

    2017-11-01

    The research and development in technology applied to computed tomography has been improve in the image quality, resulting in the best identification of diseases, and therefore an increase in the number of exams, among them the head exams can be highlighted. In order to promote a radioprotection and reduction on the dose of the general public some international agencies have stipulated dose limits to be followed and the implementation of the principles of ALARA in all establishments that use ionizing radiation. One of these principles is the optimization that should be treated with substantial attention, because the reduction of radiation doses can be feasible as long as it does not compromise the tomographic images; such practice is difficult to perform due to the lack of proper guidance. In optimization of the CT exams, not only the lowest dose is evaluated to obtain diagnostic image, but also should be knowledge the dose distribution throughout the scanned area. In this work were used a cylindrical head phantom of PMMA, a GE Discovery CT scan with 64 channels, and radiochromic films. The films were positioned in the phantom in their central region for the dose evaluation using the automatic control for the voltages of 80, 100 and 120 kV. The images were acquired from the scan of the phantom and the film readings were obtained through digital images. The results show an evaluation of the longitudinal kerma profiles, dose delivered, and the image noise was also observed using the central slice images. (author)

  20. Pharmacological interventions for phantom limb pain.

    Science.gov (United States)

    Fang, Jun; Lian, Yan-hong; Xie, Kang-jie; Cai, Shu-nü

    2013-02-01

    To review the mechanisms and current clinical application of pharmacological interventions for phantom limb pain. Both Chinese and English language literatures were searched using MEDLINE (1982 - 2011), Pubmed (1982 - 2011) and the Index of Chinese Language Literature (1982 - 2011). Data from published articles about pharmacological management of phantom limb pain in recent domestic and foreign literature were selected. Data extraction Data were mainly extracted from 96 articles which are listed in the reference section of this review. By reviewing the mechanisms and current clinical application of pharmacological interventions for phantom limb pain, including anticonvulsants, antidepressants, local anaesthetics, N-methyl-D-aspartate receptor antagonists, non-steroidal anti-inflammatory drugs, tramadol, opioids, calcitonin, capsaicin, beta-adrenergic blockers, clonidine, muscle relaxants, and emerging drugs, we examined the efficacy and safety of these medications, outlined the limitations and future directions. Although there is lack of evidence-based consensus guidelines for the pharmacological management of phantom limb pain, we recommend tricyclic antidepressants, gabapentin, tramadol, opioids, local anaesthetics and N-methyl-D-aspartate receptor antagonists as the rational options for the treatment of phantom limb pain.

  1. Innovative anisotropic phantoms for calibration of diffusion tensor imaging sequences.

    Science.gov (United States)

    Kłodowski, Krzysztof; Krzyżak, Artur Tadeusz

    2016-05-01

    The paper describes a novel type of anisotropic phantoms designed for b-matrix spatial distribution diffusion tensor imaging (BSD-DTI). Cubic plate anisotropic phantom, cylinder capillary phantom and water reference phantom are described as a complete set necessary for calibration, validation and normalization of BSD-DTI. An innovative design of the phantoms basing on enclosing the anisotropic cores in glass balls filled with liquid made for the first time possible BSD calibration with usage of echo planar imaging (EPI) sequence. Susceptibility artifacts prone to occur in EPI sequences were visibly reduced in the central region of the phantoms. The phantoms were designed for usage in a clinical scanner's head coil, but can be scaled for other coil or scanner types. The phantoms can be also used for a pre-calibration of imaging of other types of phantoms having more specific applications. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Broadband spectroscopy for characterization of tissue-like phantom optical properties

    Science.gov (United States)

    Shahin, Ali; Bachir, Wesam

    2017-12-01

    Optical phantoms are widely used for evaluating the performance of biomedical optical modalities, and hence, absorbing and scattering materials are required for the construction of optical phantoms. Towards that aim, new readily available and inexpensive black Ink (Parker) as a simulating absorber as well as Intralipid 20% as a simulating scatterer are thoroughly investigated. Broadband Transmittance and Diffuse reflectance spectroscopic measurements were performed in the visible range 400 - 700 nm. Optical properties of the phantom materials are determined. Analytical expressions for absorption and scattering coefficient related to the concentrations and wavelength of the Parker ink and Intralipid are also presented and discussed. The results show nonlinear trend in the absorption coefficient of Parker ink over the examined visible spectral range. Furthermore, Intralipid scattering coefficient variation across the mentioned spectral range shows a tissue-like scattering trend. The findings demonstrate the capability of the broadband transmission and diffuse reflectance for characterizing tissue-like phantom materials in the examined spectral range.

  3. Use of optical skin phantoms for preclinical evaluation of laser efficiency for skin lesion therapy

    Science.gov (United States)

    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

  4. Normal body scheme and absent phantom limb experience in amputees while dreaming.

    Science.gov (United States)

    Alessandria, Maria; Vetrugno, Roberto; Cortelli, Pietro; Montagna, Pasquale

    2011-12-01

    While dreaming amputees often experience a normal body image and the phantom limb may not be present. However, dreaming experiences in amputees have mainly been collected by questionnaires. We analysed the dream reports of amputated patients with phantom limb collected after awakening from REM sleep during overnight videopolysomnography (VPSG). Six amputated patients underwent overnight VPSG study. Patients were awakened during REM sleep and asked to report their dreams. Three patients were able to deliver an account of a dream. In all dreaming recalls, patients reported that the amputated limbs were intact and completely functional and they no longer experienced phantom limb sensations. Phantom limb experiences, that during wake result from a conflict between a pre-existing body scheme and the sensory information on the missing limb, were suppressed during sleep in our patients in favour of the image of an intact body accessed during dream. Copyright © 2011 Elsevier Inc. All rights reserved.

  5. Characteristics of 3D gamma evaluation according to phantom rotation error and dose gradient

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyeong Hyun; Kim, Dong Su; Kim, Tae Ho; Kang, Seong Hee; Shin, Dong Seok; Noh, Yu Yoon; Suh, Tae Seok [Dept. of Biomedical Engineering, Research Institute of Biomedical Engineering, College of Medicine, the Catholic University of Korea, Seoul (Korea, Republic of); Cho, Min Seok [Dept. of Radiation Oncology, Asan Medical Center, Seoul (Korea, Republic of)

    2016-12-15

    In intensity modulated radiation therapy (IMRT) quality assurance (QA) using dosimetric phantom, a spatial uncertainty induced from phantom set-up inevitably occurs and gamma index that is used to evaluate IMRT plan quality can be affected differently by a combination of the spatial uncertainty and magnitude of dose gradient. In this study, we investigated the impacts of dose gradient and the phantom set-up error on 3D gamma evaluation. In this study, we investigated the characteristics of gamma evaluation according to dose gradient and phantom rotation axis. As a result, 3D gamma had better performance than 2D gamma. Therefore, it can be useful for IMRT QA analysis at clinical field.

  6. A new cubic phantom for PET/CT dosimetry: Experimental and Monte Carlo characterization

    Energy Technology Data Exchange (ETDEWEB)

    Belinato, Walmir [Departamento de Ensino, Instituto Federal de Educacao, Ciencia e Tecnologia da Bahia, Campus Vitoria da Conquista, Zabele, Av. Amazonas 3150, 45030-220 Vitoria da Conquista, BA (Brazil); Silva, Rogerio M.V.; Souza, Divanizia N. [Departamento de Fisica, Universidade Federal de Sergipe-UFS, Sao Cristovao, Sergipe (Brazil); Santos, William S.; Caldas, Linda V.E. [Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242, Cidade Universitaria, 05508-000 Sao Paulo SP (Brazil); Perini, Ana P.; Neves, Lucio P. [Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242, Cidade Universitaria, 05508-000 Sao Paulo SP (Brazil); Instituto de Fisica, Universidade Federal de Uberlandia, Caixa Postal 593, 38400-902, Uberlandia, MG (Brazil)

    2015-07-01

    In recent years, positron emission tomography (PET) associated with multidetector computed tomography (MDCT) has become a diagnostic technique widely disseminated to evaluate various malignant tumors and other diseases. However, during PET/CT examinations, the doses of ionizing radiation experienced by the internal organs of patients may be substantial. To study the doses involved in PET/CT procedures, a new cubic phantom of overlapping acrylic plates was developed and characterized. This phantom has a deposit for the placement of the fluorine-18 fluoro-2-deoxy-D-glucose ({sup 18}F-FDG) solution. There are also small holes near the faces for the insertion of optically stimulated luminescence dosimeters (OSLD). The holes for OSLD are positioned at different distances from the {sup 18}F-FDG deposit. The experimental results were obtained in two PET/CT devices operating with different parameters. Differences in the absorbed doses were observed in OSLD measurements due to the non-orthogonal positioning of the detectors inside the phantom. This phantom was also evaluated using Monte Carlo simulations, with the MCNPX code. The phantom and the geometrical characteristics of the equipment were carefully modeled in the MCNPX code, in order to develop a new methodology form comparison of experimental and simulated results, as well as to allow the characterization of PET/CT equipments in Monte Carlo simulations. All results showed good agreement, proving that this new phantom may be applied for these experiments. (authors)

  7. Aesthetic Applications of Botulinum Toxin A in Asians: An International, Multidisciplinary, Pan-Asian Consensus

    Science.gov (United States)

    Sundaram, Hema; Huang, Po-Han; Hsu, Nai-Jen; Huh, Chang Hun; Wu, Woffles T.L.; Wu, Yan; Cassuto, Daniel; Kerscher, Martina J.

    2016-01-01

    Background: Botulinum toxin type A remains the most popular nonsurgical aesthetic treatment worldwide. Previous consensus statements have focused on Caucasians and on Koreans as generally representative of Asians. However, indications and dosages vary among different ethnic groups. This publication reports the results of a multidisciplinary, pan-Asian consensus focusing on incobotulinumtoxinA. Methods: A consensus group of plastic surgeons and dermatologists from Asia, Europe, and the United States convened for a live meeting in Asia, followed by a questionnaire-based Delphi procedure. Treatment of Asians in both their native countries and countries of migration was discussed. Results: For most items, the group achieved a majority consensus. A number of treatment indications, strategies, and dosages were identified in Asians, which are distinct to those previously described for Caucasians due to differences in facial morphotypes, anatomy, and cultural expectations. The group also formulated position statements for intradermal botulinum toxin type A (“mesotoxin”), body shaping with the calves as a paradigm, and reduction of parotid glands. While Asians have previously been considered a homogeneous group for the purposes of aesthetic treatment, this publication considers regional variations. A new classification of Asian facial morphotypes is proposed to aid treatment planning and implementation. Conclusions: This is the first pan-Asian consensus for aesthetic use of botulinum toxin type A. Its unique objective is to optimize treatment safety and efficacy for patients of complete or part-Asian ancestry in all regions. The recommendations for incobotulinumtoxinA may be extended with care to other botulinum toxin formulations. PMID:28293488

  8. Development of the voxel computational phantoms of pediatric patients and their application to organ dose assessment

    Science.gov (United States)

    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

  9. Critical Thinking Dispositions of Nursing Students in Asian and Non-Asian Countries: A Literature Review

    Science.gov (United States)

    Salsali, Mahvash; Tajvidi, Mansooreh; Ghiyasvandian, Shahrzad

    2013-01-01

    Critical thinking disposition represents an inclination of a person to use possessed skills in relation to critical thinking. The trend of critical thinking has been described as inner motivation to solve problems and make decisions by thinking. In nursing as a practical profession, the concept of critical thinking dispositions is important component in helping to manage complex health situations and to deal with patient issues effectively. Willingness to think critically is a prerequisite for safe and subtly performance. The results of studies show critical thinking dispositions of nursing students in Asian countries are different from non-Asian countries. Aim of this literature review was to compare critical thinking dispositions of nursing students in Asian and non-Asian countries. Literature review was done in English and Persian databases. The results showed of the 795 articles published in English and Persian language that studied critical thinking, 73 ones studied critical thinking skills and dispositions in nursing education, and relationship between teaching methods and critical thinking skills and dispositions in nursing education of different countries. Fifteen of seventy three articles assessed critical thinking dispositions in nursing students. Limited studies showed that the Asian nursing students had mostly undermining score of the critical thinking dispositions, while non-Asian countries tend to positive scores. The reasons for these differences could be due to issues such as environmental, educational methods and cultural differences. However, future studies should measure critical thinking disposition by discipline-based tools. PMID:24171885

  10. Critical thinking dispositions of nursing students in Asian and non-Asian countries: a literature review.

    Science.gov (United States)

    Salsali, Mahvash; Tajvidi, Mansooreh; Ghiyasvandian, Shahrzad

    2013-09-26

    Critical thinking disposition represents an inclination of a person to use possessed skills in relation to critical thinking. The trend of critical thinking has been described as inner motivation to solve problems and make decisions by thinking. In nursing as a practical profession, the concept of critical thinking dispositions is important component in helping to manage complex health situations and to deal with patient issues effectively. Willingness to think critically is a prerequisite for safe and subtly performance. The results of studies show critical thinking dispositions of nursing students in Asian countries are different from non-Asian countries. Aim of this literature review was to compare critical thinking dispositions of nursing students in Asian and non-Asian countries. Literature review was done in English and Persian databases. The results showed of the 795 articles published in English and Persian language that studied critical thinking, 73 ones studied critical thinking skills and dispositions in nursing education, and relationship between teaching methods and critical thinking skills and dispositions in nursing education of different countries. Fifteen of seventy three articles assessed critical thinking dispositions in nursing students. Limited studies showed that the Asian nursing students had mostly undermining score of the critical thinking dispositions, while non-Asian countries tend to positive scores. The reasons for these differences could be due to issues such as environmental, educational methods and cultural differences. However, future studies should measure critical thinking disposition by discipline-based tools.

  11. Noncontact ultrasound imaging applied to cortical bone phantoms.

    Science.gov (United States)

    Bulman, J B; Ganezer, K S; Halcrow, P W; Neeson, Ian

    2012-06-01

    The purpose of this paper was to take the first steps toward applying noncontact ultrasound (NCU) to the tasks of monitoring osteoporosis and quantitative ultrasound imaging (QUS) of cortical bone. The authors also focused on the advantages of NCU, such as its lack of reliance on a technologist to apply transducers and a layer of acoustical coupling gel, the ability of the transducers to operate autonomously as specified by preprogrammed software, and the likely reduction in statistical and systematic errors associated with the variability in the pressure applied by the clinician to the transmitting transducer that NCU might provide. The authors also undertook this study in order to find additional applications of NCU beyond its past limited usage in assessing the severity of third degree burns. A noncontact ultrasound imaging system using a pair of specially designed broadband, 1.5 MHz noncontact piezoelectric transducers and cortical bone phantoms, were used to determine bone mineral density (BMD), speed of sound (SOS), integrated response (IR), and ultrasonic transmittance. Air gaps of greater than 3 cm, two transmission and two reflection paths, and a digital signal processor were also used in the collection of data from phantoms of nominal mass densities that varied from 1.17 to 2.25 g/cm(3) and in bone mineral density from 0 to 1.7 g/cm(3). Good correlations between known BMD and measured SOS, IR, and transmittance were obtained for all 17 phantoms, and methods for quantifying and minimizing sources of systematic errors were outlined. The BMD of the phantom sets extended through most of the in vivo range found in cortical bone. A total of 16-20 repeated measurements of the SOS, thickness, and IR for the phantom set that were conducted over a period of several months showed a small variation in the range of measurements of ±1%-2%. These NCU data were shown to be in agreement with similar results using contact ultrasound to be within 1%-2%. Transmittance

  12. Coping Strategies for Managing Acculturative Stress among Asian International Students

    Science.gov (United States)

    Ra, Young-An; Trusty, Jerry

    2015-01-01

    This article examines the effects of specific coping strategies on managing acculturative stress and acculturation of Asian international students, based on a sample of 220 Asian international students in the U.S. The data were analyzed with hierarchical multiple regression using Baron and Kenny's (1986) mediation procedure. The results supported…

  13. A polygon-surface reference Korean male phantom (PSRK-Man) and its direct implementation in Geant4 Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chan Hyeong; Jeong, Jong Hwi [Department of Nuclear Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Bolch, Wesley E [Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, FL 32611 (United States); Cho, Kun-Woo [Korea Institute of Nuclear Safety, 19 Guseong-dong, Yuseong-gu, Daejeon 305-600 (Korea, Republic of); Hwang, Sung Bae, E-mail: chkim@hanyang.ac.kr [Department of Physical Therapy, Kyungbuk College, Hyucheon 2-dong, Yeongju-si, Gyeongbuk 750-712 (Korea, Republic of)

    2011-05-21

    Even though the hybrid phantom embodies both the anatomic reality of voxel phantoms and the deformability of stylized phantoms, it must be voxelized to be used in a Monte Carlo code for dose calculation or some imaging simulation, which incurs the inherent limitations of voxel phantoms. In the present study, a voxel phantom named VKH-Man (Visible Korean Human-Man), was converted to a polygon-surface phantom (PSRK-Man, Polygon-Surface Reference Korean-Man), which was then adjusted to the Reference Korean data. Subsequently, the PSRK-Man polygon phantom was directly, without any voxelization process, implemented in the Geant4 Monte Carlo code for dose calculations. The calculated dose values and computation time were then compared with those of HDRK-Man (High Definition Reference Korean-Man), a corresponding voxel phantom adjusted to the same Reference Korean data from the same VKH-Man voxel phantom. Our results showed that the calculated dose values of the PSRK-Man surface phantom agreed well with those of the HDRK-Man voxel phantom. The calculation speed for the PSRK-Man polygon phantom though was 70-150 times slower than that of the HDRK-Man voxel phantom; that speed, however, could be acceptable in some applications, in that direct use of the surface phantom PSRK-Man in Geant4 does not require a separate voxelization process. Computing speed can be enhanced, in future, either by optimizing the Monte Carlo transport kernel for the polygon surfaces or by using modern computing technologies such as grid computing and general-purpose computing on graphics processing units programming.

  14. A polygon-surface reference Korean male phantom (PSRK-Man) and its direct implementation in Geant4 Monte Carlo simulation

    Science.gov (United States)

    Kim, Chan Hyeong; Jeong, Jong Hwi; Bolch, Wesley E.; Cho, Kun-Woo; Hwang, Sung Bae

    2011-05-01

    Even though the hybrid phantom embodies both the anatomic reality of voxel phantoms and the deformability of stylized phantoms, it must be voxelized to be used in a Monte Carlo code for dose calculation or some imaging simulation, which incurs the inherent limitations of voxel phantoms. In the present study, a voxel phantom named VKH-Man (Visible Korean Human-Man), was converted to a polygon-surface phantom (PSRK-Man, Polygon-Surface Reference Korean-Man), which was then adjusted to the Reference Korean data. Subsequently, the PSRK-Man polygon phantom was directly, without any voxelization process, implemented in the Geant4 Monte Carlo code for dose calculations. The calculated dose values and computation time were then compared with those of HDRK-Man (High Definition Reference Korean-Man), a corresponding voxel phantom adjusted to the same Reference Korean data from the same VKH-Man voxel phantom. Our results showed that the calculated dose values of the PSRK-Man surface phantom agreed well with those of the HDRK-Man voxel phantom. The calculation speed for the PSRK-Man polygon phantom though was 70-150 times slower than that of the HDRK-Man voxel phantom; that speed, however, could be acceptable in some applications, in that direct use of the surface phantom PSRK-Man in Geant4 does not require a separate voxelization process. Computing speed can be enhanced, in future, either by optimizing the Monte Carlo transport kernel for the polygon surfaces or by using modern computing technologies such as grid computing and general-purpose computing on graphics processing units programming.

  15. A polygon-surface reference Korean male phantom (PSRK-Man) and its direct implementation in Geant4 Monte Carlo simulation.

    Science.gov (United States)

    Kim, Chan Hyeong; Jeong, Jong Hwi; Bolch, Wesley E; Cho, Kun-Woo; Hwang, Sung Bae

    2011-05-21

    Even though the hybrid phantom embodies both the anatomic reality of voxel phantoms and the deformability of stylized phantoms, it must be voxelized to be used in a Monte Carlo code for dose calculation or some imaging simulation, which incurs the inherent limitations of voxel phantoms. In the present study, a voxel phantom named VKH-Man (Visible Korean Human-Man), was converted to a polygon-surface phantom (PSRK-Man, Polygon-Surface Reference Korean-Man), which was then adjusted to the Reference Korean data. Subsequently, the PSRK-Man polygon phantom was directly, without any voxelization process, implemented in the Geant4 Monte Carlo code for dose calculations. The calculated dose values and computation time were then compared with those of HDRK-Man (High Definition Reference Korean-Man), a corresponding voxel phantom adjusted to the same Reference Korean data from the same VKH-Man voxel phantom. Our results showed that the calculated dose values of the PSRK-Man surface phantom agreed well with those of the HDRK-Man voxel phantom. The calculation speed for the PSRK-Man polygon phantom though was 70-150 times slower than that of the HDRK-Man voxel phantom; that speed, however, could be acceptable in some applications, in that direct use of the surface phantom PSRK-Man in Geant4 does not require a separate voxelization process. Computing speed can be enhanced, in future, either by optimizing the Monte Carlo transport kernel for the polygon surfaces or by using modern computing technologies such as grid computing and general-purpose computing on graphics processing units programming.

  16. Analysis of biological tissues in infant chest for the development of an equivalent radiographic phantom

    Energy Technology Data Exchange (ETDEWEB)

    Pina, D. R.; Souza, Rafael T. F.; Duarte, Sergio B.; Alvarez, Matheus; Miranda, Jose R. A. [Faculdade de Medicina de Botucatu, Departamento de Doencas Tropicais e Diagnostico por Imagem, Universidade Estadual Paulista-UNESP, Distrito de Rubiao Junior S/N, Botucatu, 18618-000 Sao Paulo (Brazil); Instituto de Biociencias de Botucatu, Departamento de Fisica e Biofisica, Universidade Estadual Paulista-UNESP, Distrito de Rubiao Junior S/N, Botucatu, 18618-000 Sao Paulo (Brazil); Centro Brasileiro de Pesquisas Fisicas-CBPF/MCT, Rio de Janeiro 22290-180 (Brazil); Instituto de Biociencias de Botucatu, Departamento de Fisica e Biofisica, Universidade Estadual Paulista-UNESP, Distrito de Rubiao Junior S/N, Botucatu, 18618-000 Sao Paulo (Brazil); Instituto de Biociencias de Botucatu, Departamento de Fisica e Biofisica, Universidade Estadual Paulista-UNESP, Distrito de Rubiao Junior S/N, Botucatu, 18618-000 Sao Paulo (Brazil)

    2012-03-15

    Purpose: The main purpose of the present study was to determine the amounts of different tissues in the chest of the newborn patient (age {<=}1 year), with the aim of developing a homogeneous phantom chest equivalent. This type of phantom is indispensable in the development of optimization procedures for radiographic techniques, including dosimetric control, which is a crucial aspect of pediatric radiology. The authors present a systematic set of procedures, including a computational algorithm, to estimate the amounts of tissues and thicknesses of the corresponding simulator material plates used to construct the phantom. Methods: The Gaussian fit of computed tomographic (CT) analysis was applied to classify and quantify different biological tissues. The methodology is summarized with a computational algorithm, which was used to quantify tissues through automated CT analysis. The thicknesses of the equivalent homogeneous simulator material plates were determined to construct the phantom. Results: A total of 180 retrospective CT examinations with anterior-posterior diameter values ranging 8.5-13.0 cm were examined. The amounts of different tissues were evaluated. The results provided elements to construct a phantom to simulate the infant chest in the posterior-anterior or anterior-posterior (PA/AP) view. Conclusions: To our knowledge, this report represents the first demonstration of an infant chest phantom dedicated to the radiology of children younger than one year. This phantom is a key element in the development of clinical charts for optimizing radiographic technique in pediatric patients. Optimization procedures for nonstandard patients were reported previously [Pina et al., Phys. Med. Biol. 49, N215-N226 (2004) and Pina et al., Appl. Radiat. Isot. 67, 61-69 (2009)]. The constructed phantom represents a starting point to obtain radiologic protocols for the infant patient.

  17. Cosmological perturbations in transient phantom inflation scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Richarte, Martin G. [Universidade Federal do Parana, Departamento de Fisica, Caixa Postal 19044, Curitiba (Brazil); Universidad de Buenos Aires, Ciudad Universitaria 1428, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina); Kremer, Gilberto M. [Universidade Federal do Parana, Departamento de Fisica, Caixa Postal 19044, Curitiba (Brazil)

    2017-01-15

    We present a model of inflation where the inflaton is accommodated as a phantom field which exhibits an initial transient pole behavior and then decays into a quintessence field which is responsible for a radiation era. We must stress that the present unified model only deals with a single field and that the transition between the two eras is achieved in a smooth way, so the model does not suffer from the eternal inflation issue. We explore the conditions for the crossing of the phantom divide line within the inflationary era along with the structural stability of several critical points. We study the behavior of the phantom field within the slow-climb approximation along with the necessary conditions to have sufficient inflation. We also examine the model at the level of classical perturbations within the Newtonian gauge and determine the behavior of the gravitational potential, contrast density and perturbed field near the inflation stage and the subsequent radiation era. (orig.)

  18. Photoacoustic investigation of a neonatal skull phantom

    Science.gov (United States)

    Volinski, Bridget; Hariri, Ali; Fatima, Afreen; Xu, Qiuyun; Nasiriavanaki, Mohammadreza

    2017-03-01

    There is a need for continued research into the diagnosis, prevention and cure of neonatal brain disease and disorders. These disorders lead to fatalities and developmental disorders in infants. Non-invasive imaging techniques are being researched for this purpose. However, the availability of neonatal skull samples for this work is very low. A phantom can be used to simulate the neonatal skull and brain to improve imaging techniques. This study selects a phantom of polyurethane and titanium dioxide and proves its value as a replacement for neonatal skull in research. The methods used for this proof are validation of choice against the literature, transmissivity and acoustic experimentation compared to existing literature, and finally photoacoustic evaluation of the final choice to show its usefulness as a neonatal skull phantom.

  19. MRI phantoms - are there alternatives to agar?

    Directory of Open Access Journals (Sweden)

    Alexandra Hellerbach

    Full Text Available The suitability of different gelling agents as MRI phantoms was evaluated in terms of homogeneity, gel stability and reproducibility. Time and effort for preparation were also taken into account. The relaxation times of various gel compositions were estimated. Carbomer-980 and Carbopol-974P were determined to be promising novel phantom materials. These gelling agents are readily available, inexpensive and easy to handle given that thermal treatment is not required. Furthermore, the viscoelasticity of their polymer network is pH-dependent. With such characteristics, it was even possible to embed sensitive objects and retrieve them after testing. This was demonstrated with a fiber phantom for Diffusion Weighted MRI applications. Since Carbomer-980 and Carbopol-974P are non-hazardous, they are also suitable for multimodal setups (e.g., MRI as well as ultrasonic imaging.

  20. Stable phantom materials for ultrasound and optical imaging

    Science.gov (United States)

    Cabrelli, Luciana C.; Pelissari, Pedro I. B. G. B.; Deana, Alessandro M.; Carneiro, Antonio A. O.; Pavan, Theo Z.

    2017-01-01

    Phantoms mimicking the specific properties of biological tissues are essential to fully characterize medical devices. Water-based materials are commonly used to manufacture phantoms for ultrasound and optical imaging techniques. However, these materials have disadvantages, such as easy degradation and low temporal stability. In this study, we propose an oil-based new tissue-mimicking material for ultrasound and optical imaging, with the advantage of presenting low temporal degradation. A styrene-ethylene/butylene-styrene (SEBS) copolymer in mineral oil samples was made varying the SEBS concentration between 5%-15%, and low-density polyethylene (LDPE) between 0%-9%. Acoustic properties, such as the speed of sound and the attenuation coefficient, were obtained using frequencies ranging from 1-10 MHz, and were consistent with that of soft tissues. These properties were controlled varying SEBS and LDPE concentration. To characterize the optical properties of the samples, the diffuse reflectance and transmittance were measured. Scattering and absorption coefficients ranging from 400 nm-1200 nm were calculated for each compound. SEBS gels are a translucent material presenting low optical absorption and scattering coefficients in the visible region of the spectrum, but the presence of LDPE increased the turbidity. Adding LDPE increased the absorption and scattering of the phantom materials. Ultrasound and photoacoustic images of a heterogeneous phantom made of LDPE/SEBS containing a spherical inclusion were obtained. Annatto dye was added to the inclusion to enhance the optical absorbance. The results suggest that copolymer gels are promising for ultrasound and optical imaging, making them also potentially useful for photoacoustic imaging.

  1. Stable phantom materials for ultrasound and optical imaging.

    Science.gov (United States)

    Cabrelli, Luciana C; Pelissari, Pedro I B G B; Deana, Alessandro M; Carneiro, Antonio A O; Pavan, Theo Z

    2017-01-21

    Phantoms mimicking the specific properties of biological tissues are essential to fully characterize medical devices. Water-based materials are commonly used to manufacture phantoms for ultrasound and optical imaging techniques. However, these materials have disadvantages, such as easy degradation and low temporal stability. In this study, we propose an oil-based new tissue-mimicking material for ultrasound and optical imaging, with the advantage of presenting low temporal degradation. A styrene-ethylene/butylene-styrene (SEBS) copolymer in mineral oil samples was made varying the SEBS concentration between 5%-15%, and low-density polyethylene (LDPE) between 0%-9%. Acoustic properties, such as the speed of sound and the attenuation coefficient, were obtained using frequencies ranging from 1-10 MHz, and were consistent with that of soft tissues. These properties were controlled varying SEBS and LDPE concentration. To characterize the optical properties of the samples, the diffuse reflectance and transmittance were measured. Scattering and absorption coefficients ranging from 400 nm-1200 nm were calculated for each compound. SEBS gels are a translucent material presenting low optical absorption and scattering coefficients in the visible region of the spectrum, but the presence of LDPE increased the turbidity. Adding LDPE increased the absorption and scattering of the phantom materials. Ultrasound and photoacoustic images of a heterogeneous phantom made of LDPE/SEBS containing a spherical inclusion were obtained. Annatto dye was added to the inclusion to enhance the optical absorbance. The results suggest that copolymer gels are promising for ultrasound and optical imaging, making them also potentially useful for photoacoustic imaging.

  2. New polymer-based phantom for photoacoustic imaging

    Science.gov (United States)

    Kawaguchi, Yasushi; Iwazaki, Hideaki; Ida, Taiichiro; Nishi, Taiji; Tanikawa, Yukari; Nitta, Naotaka

    2014-03-01

    We will report newly developed polymer-based phantom for photoacoustic (PA) imaging systems. Phantoms are important for performance evaluation and calibration of new modalities; however, there is no established method for making phantoms with no long-term change. We have developed skin mimicking phantoms simulating both optical and acoustic properties (i.e. optical scattering and absorption coefficients, and sound velocity). Furthermore, the phantoms are able to give accurate simulation of blood vessels by Inkjet-printing. Newly developed phantoms are consisted of castor oil included acrylic block copolymer and we can fabricate 0.8mm or less thick sheets and pile them using their self-adhesiveness.

  3. Development of newborn and 1-year-old reference phantoms based on polygon mesh surfaces.

    Science.gov (United States)

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

    2013-09-01

    The purpose of this study is the development of paediatric reference phantoms for newborn and 1-year-old infants to be used for the calculation of organ and tissue equivalent doses in radiation protection. The study proposes a method for developing anatomically highly sophisticated paediatric phantoms without using medical images. The newborn and 1-year-old hermaphrodite phantoms presented here were developed using three-dimensional (3D) modelling software applied to anatomical information taken from atlases, textbooks and images provided by the Department of Anatomy of the Federal University of Pernambuco, Brazil. 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 agree with corresponding data given by the International Commission on Radiological Protection for newborn and 1-year-old reference children. Bones were segmented into cortical bone, spongiosa, medullary marrow and cartilage to allow for the use of μCT images of trabecular bone for skeletal dosimetry. Anatomical results show 3D images of the phantoms' surfaces, organs and skeletons, as well as tables with organ and tissue masses or skeletal tissue volumes. Dosimetric results present comparisons of organ and tissue absorbed doses or specific absorbed fractions between the newborn and 1-year-old phantoms and corresponding data for other paediatric stylised or voxel phantoms. Most differences were found to be below 10%.

  4. Strain measurement from 3D micro-CT images of a breast-mimicking phantom.

    Science.gov (United States)

    Lee, Soo Yeol; Kim, Gyu Won; Han, Byung Hee; Cho, Min Hyoung

    2011-03-01

    Strain distribution in compressed tissues gives information about elasticity of the tissues. We have measured strain from two sets of 3D micro-CT images of a breast-mimicking phantom; one obtained without compressing the phantom and the other with compressing it. To measure strain, we first calculated compression-induced displacements of high-intensity feature patterns in the image. In measuring displacement of a pixel of interest, we searched the pixel in the compressed-phantom image, whose surrounding resembles the uncompressed-phantom image most closely, using the image correlation technique. From the displacement data, we calculated average strain at a region of interest. With the calculated average strains, we could distinguish the hard inclusion in the phantom which was not distinguishable from the background body of the phantom in the ordinary micro-CT images. The calculated strains account for stiffness of the tissue of interest, one of the important parameters for diagnosing malignant tissues. We present experimental results of the displacement and strain measurement along with FEM analysis results. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. [Phantom limb pain. Psychological treatment strategies].

    Science.gov (United States)

    Diers, M; Flor, H

    2013-04-01

    Similar to other pain syndromes phantom limb pain is characterized by learning and memory processes that maintain the pain and increase maladaptive plastic changes of the brain: therefore, psychological interventions that change maladaptive memory processes are useful. In addition to traditional psychological interventions, such as pain management training and biofeedback, more recent developments that involve sensory discrimination training, mirror treatment, graded motor imagery, prosthesis training and training in virtual reality are interesting. These interventions not only reduce phantom limb pain but also reverse the associated maladaptive brain changes.

  6. Successful peripheral neuromodulation for phantom limb pain.

    Science.gov (United States)

    Cornish, Philip; Wall, Cindy

    2015-04-01

    For decades, the heterogeneity of the amputee population and the complex interaction of biopsychosocial factors have confounded researchers' attempts to develop an effective treatment for phantom limb pain. Therefore, it remains difficult to treat, and affected patients often experience decreased quality of life, increased psychological distress, and poorer health outcomes. In the case study, we report a novel strategy for the peripheral placement of neuromodulation leads for the treatment of phantom limb pain in a patient who subsequently described complete and consistent pain relief independent of significant variations in psychosocial stress. Wiley Periodicals, Inc.

  7. Static phantom wormholes of finite size

    Science.gov (United States)

    Cataldo, Mauricio; Orellana, Fabian

    2017-09-01

    In this paper we derive new static phantom traversable wormholes by assuming a shape function with a quadratic dependence on the radial coordinate r . We mainly focus our study on wormholes sustained by exotic matter with positive energy density (as seen by any static observer) and a variable equation of state pr/ρ wormhole spacetimes extending to infinity, we show that a quadratic shape function allows us to construct static spacetimes of finite size, composed of a phantom wormhole connected to an anisotropic spherically symmetric distribution of dark energy. The wormhole part of the full spacetime does not fulfill the dominant energy condition, while the dark energy part does.

  8. Social anxiety among East Asians in North America: East Asian socialization or the challenge of acculturation?

    Science.gov (United States)

    Hsu, Lorena; Woody, Sheila R; Lee, Hoon-Jin; Peng, Yunshi; Zhou, Xiaolu; Ryder, Andrew G

    2012-04-01

    North American research has consistently reported higher social anxiety among people of Asian heritage compared to people of Western heritage. The present study used a cross-national sample of 692 university students to explore explanatory hypotheses using planned contrasts of group differences in social anxiety and related variables. The East Asian socialization hypothesis proposed social anxiety would show a linear relation corresponding to the degree of exposure to East Asian cultural norms. This hypothesis was not supported. The cultural discrepancy hypothesis examined whether bicultural East Asian participants (residing in Canada) would endorse higher social anxiety in comparison to unicultural participants (Western-heritage Canadians and native Koreans and Chinese). Compared to unicultural participants, bicultural East Asian participants reported higher social anxiety and depression, a relation that was partially mediated by bicultural participants' reports of lower self-efficacy about initiating social relationships and lower perceived social status. Overall, the results suggest higher reports of social anxiety among bicultural East Asians may be conceptualized within the context of cultural discrepancy with the mainstream culture. PsycINFO Database Record (c) 2012 APA, all rights reserved.

  9. Development and characterization of rodent cardiac phantoms: comparison with in vivo cardiac imaging.

    Science.gov (United States)

    Fortune, Steven; Jansen, Maurits A; Anderson, Tom; Gray, Gillian A; Schneider, Jürgen E; Hoskins, Peter R; Marshall, Ian

    2012-10-01

    The increasing availability of rodent models of human cardiovascular disease has led to a need to translate noninvasive imaging techniques such as magnetic resonance imaging (MRI) from the clinic to the animal laboratory. The aim of this study was to develop phantoms simulating the short-axis view of left ventricular motion of rats and mice, thus reducing the need for live animals in the development of MRI. Cylindrical phantoms were moulded from polyvinyl alcohol (PVA) Cryogel and attached via stiff water-filled tubing to a gear pump. Pulsatile distension of the phantoms was effected by suitable programming of the pump. Cine MRI scanning was carried out at 7 T and compared with in vivo rodent cardiac imaging. Suitable pulsatile performance was achieved with phantoms for which the PVA material had been subjected to two freeze-thaw cycles, resulting in T1 and T2 relaxation time constants of 1656±124 ms and 55±10 ms, respectively. For the rat phantom operating at 240 beats per min (bpm), the dynamic range of the outer diameter was from 10.3 to 12.4 mm with the wall thickness varying between 1.9 and 1.2 mm. Corresponding figures for the mouse phantom at 480 bpm were outer diameter range from 5.4 to 6.4 mm and wall thickness from 1.5 to 1.2 mm. Dynamic cardiac phantoms simulating rodent left ventricular motion in the short-axis view were successfully developed and compared with in vivo imaging. The phantoms can be used for future development work with reduced need of live animals. Copyright © 2012 Elsevier Inc. All rights reserved.

  10. 3D dosimetric validation of motion compensation concepts in radiotherapy using an anthropomorphic dynamic lung phantom.

    Science.gov (United States)

    Mann, P; Witte, M; Moser, T; Lang, C; Runz, A; Johnen, W; Berger, M; Biederer, J; Karger, C P

    2017-01-21

    In this study, we developed a new setup for the validation of clinical workflows in adaptive radiation therapy, which combines a dynamic ex vivo porcine lung phantom and three-dimensional (3D) polymer gel dosimetry. The phantom consists of an artificial PMMA-thorax and contains a post mortem explanted porcine lung to which arbitrary breathing patterns can be applied. A lung tumor was simulated using the PAGAT (polyacrylamide gelatin gel fabricated at atmospheric conditions) dosimetry gel, which was evaluated in three dimensions by magnetic resonance imaging (MRI). To avoid bias by reaction with oxygen and other materials, the gel was collocated inside a BAREX(™) container. For calibration purposes, the same containers with eight gel samples were irradiated with doses from 0 to 7 Gy. To test the technical feasibility of the system, a small spherical dose distribution located completely within the gel volume was planned. Dose delivery was performed under static and dynamic conditions of the phantom with and without motion compensation by beam gating. To verify clinical target definition and motion compensation concepts, the entire gel volume was homogeneously irradiated applying adequate margins in case of the static phantom and an additional internal target volume in case of dynamically operated phantom without and with gated beam delivery. MR-evaluation of the gel samples and comparison of the resulting 3D dose distribution with the planned dose distribution revealed a good agreement for the static phantom. In case of the dynamically operated phantom without motion compensation, agreement was very poor while additional application of motion compensation techniques restored the good agreement between measured and planned dose. From these experiments it was concluded that the set up with the dynamic and anthropomorphic lung phantom together with 3D-gel dosimetry provides a valuable and versatile tool for geometrical and dosimetrical validation of motion compensated

  11. Wedge factor constituents of high-energy photon beams: head and phantom scatter dose components.

    Science.gov (United States)

    Heukelom, S; Lanson, J H; Mijnheer, B J

    1994-07-01

    The head and phantom scatter contribution to the output of a treatment machine have been determined for open and wedged 60Co gamma-ray beams and 4, 8, 16 and 25 MV X-ray beams, using an extended and a small-sized phantom. The wedge factor variation with field size and phantom depth have been analysed as a function of both scatter components. For the wedged beams a stronger increase of the head scatter contribution with field size, i.e. 4-9% for field sizes increasing from 5 cm x 5 cm to 20 cm x 20 cm, has been observed compared with open beams. This result indicates that the wedge factor variation with field size is related to a change of the primary photon fluence. Our study shows that the ratio of the head and phantom scatter contribution for the wedged and open beams remains unchanged for all beams except the 4 and 25 MV X-ray beam. This implies that, except for these latter energies, the variation of the wedge factor with phantom depth is determined by the wedge-induced change of the primary photon energy fluence. For the 4 and 25 MV X-ray beam it is shown that the wedge factor is also influenced by a change of the phantom scatter contribution. The wedge factor for the 25 MV X-ray beam is strongly influenced by the electron contamination for phantom depths up to 6 cm. For the 60Co and the 4 MV photon beam it is shown that the wedge factor decreases slightly with increasing source-to-skin distance due to a reduced contribution to the total dose from photons scattered in the wedge. For clinical use, an algorithm is given to calculate the wedge factor variation with field size and phantom depth.

  12. The phantom and the supernumerary phantom limb: historical review and new case.

    Science.gov (United States)

    Cipriani, Gabriele; Picchi, Lucia; Vedovello, Marcella; Nuti, Angelo; Fiorino, Mario Di

    2011-12-01

    The way we experience the world is determined by the way our brain works. The phantom limb phenomenon, which is a delusional belief of the presence of a non-existent limb, has a particular fascination in neurology. This positive phenomenon of the phantom limb raises theoretical questions about its nature. After a stroke, some patients experience the perception of an extra limb in addition to the regular set of two arms and two legs. This complex cognitive and perceptual distortion is called supernumerary phantom limb. Here, we review the pathogenesis and historical aspects, and report a new case.

  13. South Asian Cluster

    OpenAIRE

    Ionel Sergiu Pirju

    2014-01-01

    This article aims at presenting the South Asian cluster composed of India, Indonesia, Iran and Malaysia, the intercultural values that characterizes it, the supported leadership style and tracing the main macroeconomic considerations which characterizes them. The research is synchronic, analysing the contemporary situation of these countries without reference to their evolution in time, by using the positivist paradigm that explains the reality at one point. It will be analysed th...

  14. Asian American Adolescent Identity

    OpenAIRE

    Ohm, Julie Juhye

    1999-01-01

    The formation of ego identity in Asian American late adolescents attending Virginia Tech was examined within the frameworks of Erikson's psychosocial theory and Berry, Trimble, and Olmedo's model of acculturation. Ego identity was measured using the Achieved sub-scale of the Revised Version of the Extended Objective Measure of Ego Identity Status, an instrument based on the theoretical constructs of Erikson. Ethnic identity was measured using the Multigroup Ethnic Identity Measure and America...

  15. Asian Media Productions

    DEFF Research Database (Denmark)

    This work consists of 12 essays on different aspects of Asian media by Japanese, European, and American scholars, many of whom have themselves been involved in the production of media forms. Working in the fields of anthropology, media and cultural studies, and on the basis of hands-on research......, they have written a book on the social practices and cultural attitudes of people producing, reading, watching and listening to different kinds of media in Japan, China, Taiwan, Indonesia, Vietnam, Singapore and India....

  16. East Asian welfare regime

    DEFF Research Database (Denmark)

    Abrahamson, Peter

    2017-01-01

    The paper asks if East Asian welfare regimes are still productivist and Confucian? And, have they developed public care policies? The literature is split on the first question but (mostly) confirmative on the second. Care has to a large, but insufficient extent, been rolled out in the region. Pol...... focusing on outcomes or causal links tend to suggest that legacies prevail, but there is (nearly) consensus that Confucianism exercises great influence in the whole region....

  17. Biologically relevant photoacoustic imaging phantoms with tunable optical and acoustic properties

    Science.gov (United States)

    Vogt, William C.; Jia, Congxian; Wear, Keith A.; Garra, Brian S.; Joshua Pfefer, T.

    2016-10-01

    Established medical imaging technologies such as magnetic resonance imaging and computed tomography rely on well-validated tissue-simulating phantoms for standardized testing of device image quality. The availability of high-quality phantoms for optical-acoustic diagnostics such as photoacoustic tomography (PAT) will facilitate standardization and clinical translation of these emerging approaches. Materials used in prior PAT phantoms do not provide a suitable combination of long-term stability and realistic acoustic and optical properties. Therefore, we have investigated the use of custom polyvinyl chloride plastisol (PVCP) formulations for imaging phantoms and identified a dual-plasticizer approach that provides biologically relevant ranges of relevant properties. Speed of sound and acoustic attenuation were determined over a frequency range of 4 to 9 MHz and optical absorption and scattering over a wavelength range of 400 to 1100 nm. We present characterization of several PVCP formulations, including one designed to mimic breast tissue. This material is used to construct a phantom comprised of an array of cylindrical, hemoglobin-filled inclusions for evaluation of penetration depth. Measurements with a custom near-infrared PAT imager provide quantitative and qualitative comparisons of phantom and tissue images. Results indicate that our PVCP material is uniquely suitable for PAT system image quality evaluation and may provide a practical tool for device validation and intercomparison.

  18. [Cortical reorganization and pain. Empirical findings and therapeutic implication using the example of phantom pain].

    Science.gov (United States)

    Huse, E; Larbig, W; Birbaumer, N; Flor, H

    2001-04-01

    The neuroscientific research of the past years has shown that extensive plastic change occurs in the adult human brain. The functional reorganization of the somatosensory and motor maps related to phantom limb pain is described. Subsequent to deafferentation amputees with phantom limb pain show a shift of neighbouring representation zones into the deafferented zone of the somatosensory and motor cortex that can be detected with noninvasive neuroimaging methods. This reorganization of the sensory and motor maps is not found in painfree amputees and persons with congenital loss of a limb. We discuss a model of the development of phantom limb pain that incorporates both peripheral and central factors and assigns an important role to chronic pain before the amputation. The modulation of plasticity and phantom limb pain by anesthesiological interventions is described and the results of preemptive analgesia for the prevention of phantom limb pain are discussed. Opioid treatment and behaviorally relevant stimulation are effective means to eliminate phantom limb pain and cortical somatosensory pain memories.

  19. Event-Related Functional Magnetic Resonance Images during the Perception of Phantom Limb. A Brushing Task.

    Science.gov (United States)

    Pasaye, E H; Gutiérrez, R A; Alcauter, S; Mercadillo, R E; Aguilar-Castañeda, E; De Iturbe, M; Romero-Romo, J; Barrios, F A

    2010-12-01

    The phantom limb phenomenon has been used in amputee patients as a paradigm to study plasticity, mainly of the sensorimotor cortex. Nevertheless, most functional studies have been done in upper limb amputee patients using magnetoencephalography and functional magnetic resonance image imaging (fMRI). In addition, the actual experience of phantom limb sensation has not been widely used to study the neural mechanism of the human brain as a conscious knowledge of the phantom limb perception like the integration of the body image in amputee patients. fMRI studies of patients with lower limb amputation have recently been published, but none of these used an event-related design to try to observe only the stimulus application, correlating images with the subject's indication of phantom perception and discarding images with no phantom perception. In this work, we used the event-related fMRI design in two right-handed patients with identical right, transfemoral amputations, performing the same sensitive stimulation in a 3.0 T MR scanner. For comparison, we applied the same paradigm to six control subjects to compare the resulting functional maps. We found areas with statistical significance in the sensorimotor cortex contralateral to the site of stimulation, in the parietal lobe in Brodmann areas 3 in both cases (Patients and Control Subjects), but we also found activation in the Brodmann areas 6, 40, and 5 with stimulation of the stump. We observed a specific activation of the frontoparietal circuit during phantom limb perception in both amputee patients.

  20. Incorporation of detailed eye model into polygon-mesh versions of ICRP-110 reference phantoms.

    Science.gov (United States)

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

    2015-11-21

    The dose coefficients for the eye lens reported in ICRP 2010 Publication 116 were calculated using both a stylized model and the ICRP-110 reference phantoms, according to the type of radiation, energy, and irradiation geometry. To maintain consistency of lens dose assessment, in the present study we incorporated the ICRP-116 detailed eye model into the converted polygon-mesh (PM) version of the ICRP-110 reference phantoms. After the incorporation, the dose coefficients for the eye lens were calculated and compared with those of the ICRP-116 data. The results showed generally a good agreement between the newly calculated lens dose coefficients and the values of ICRP 2010 Publication 116. Significant differences were found for some irradiation cases due mainly to the use of different types of phantoms. Considering that the PM version of the ICRP-110 reference phantoms preserve the original topology of the ICRP-110 reference phantoms, it is believed that the PM version phantoms, along with the detailed eye model, provide more reliable and consistent dose coefficients for the eye lens.

  1. Biologically relevant photoacoustic imaging phantoms with tunable optical and acoustic properties.

    Science.gov (United States)

    Vogt, William C; Jia, Congxian; Wear, Keith A; Garra, Brian S; Joshua Pfefer, T

    2016-10-01

    Established medical imaging technologies such as magnetic resonance imaging and computed tomography rely on well-validated tissue-simulating phantoms for standardized testing of device image quality. The availability of high-quality phantoms for optical-acoustic diagnostics such as photoacoustic tomography (PAT) will facilitate standardization and clinical translation of these emerging approaches. Materials used in prior PAT phantoms do not provide a suitable combination of long-term stability and realistic acoustic and optical properties. Therefore, we have investigated the use of custom polyvinyl chloride plastisol (PVCP) formulations for imaging phantoms and identified a dual-plasticizer approach that provides biologically relevant ranges of relevant properties. Speed of sound and acoustic attenuation were determined over a frequency range of 4 to 9 MHz and optical absorption and scattering over a wavelength range of 400 to 1100 nm. We present characterization of several PVCP formulations, including one designed to mimic breast tissue. This material is used to construct a phantom comprised of an array of cylindrical, hemoglobin-filled inclusions for evaluation of penetration depth. Measurements with a custom near-infrared PAT imager provide quantitative and qualitative comparisons of phantom and tissue images. Results indicate that our PVCP material is uniquely suitable for PAT system image quality evaluation and may provide a practical tool for device validation and intercomparison.

  2. Supernumerary phantom limb in a patient with basal ganglia hemorrhage - a case report and review of the literature.

    Science.gov (United States)

    Kim, Hang-Rai; Han, Jee-Young; Park, Young Ho; Kim, Beom Joon; Yang, Wookjin; Kim, SangYun

    2017-09-08

    Supernumerary phantom limb (SPL) is a rare neurologic phenomenon, in which a patient misperceives an extra limb in addition to the original set of limbs. We report a case of SPL in a patient with a right basal ganglia hemorrhage and review the previous literature about this peculiar phenomenon. Two days after the event of a right basal ganglia hemorrhage, a 78-year-old male reported a phantom arm protruding from his left shoulder. He could not see or touch the phantom arm but he felt the presence of an addition arm lateral to his paretic arm. Pain or sensory discomfort were absent in either the paretic arm or the phantom arm. He stated that he could intentionally move the phantom arm independent of his paretic arm. The examination showed that the passive movement of his paretic arm did not elicit any movement of his phantom arm. We diagnosed the SPL as a complication of the hypertensive basal ganglia hemorrhage and treated him with anti-hypertensive medications. His phantom arm persisted for 3 weeks, and it gradually faded away. SPL had been reported as a rare complication of various types of cerebral lesions. Right hemispheric lesions were most frequently associated with the SPL. Considering the intentional movement of the phantom arm, we deduced that the SPL might result from the impairment of the sensory feedback system for both internal body image and motor movement.

  3. Phantom limb pain in young cancer-related amputees: Recent experience at St. Jude Children’s Research Hospital

    Science.gov (United States)

    Burgoyne, Laura L.; Billups, Catherine A.; Jirón, José L.; Kaddoum, Roland N.; Wright, Becky B.; Bikhazi, George B.; Parish, Mary Edna; Pereiras, Lilia A.

    2013-01-01

    Objectives This study in children and young adults having cancer-related amputation aimed to examine the incidence of phantom limb pain in the first year after amputation and also the proportion of patients who had pre-amputation pain. Methods A retrospective review of medical records was undertaken. The proportion of patients with phantom limb pain was reported. Fisher’s exact test was used to examine the association between phantom limb pain and the presence of pre-amputation pain and between phantom limb pain and age (≤18 years vs. >18 years). Results 26 amputations were performed on 25 patients. During the year following amputation, 76% of patients had experienced phantom limb pain at some time. After 1 year, though, only 10% still had phantom limb pain. Pre-amputation pain was present in 64% of patients. Although both of our patients with PLP at 1 year were young adults (≥18 years) and both had pre-amputation pain, we found no statistically significant associations between age or the presence of pre-amputation pain with phantom limb pain. Discussion Phantom limb pain following cancer related amputation in children and young adults appears to be common but generally short lived in most patients. PMID:21785344

  4. Perspectives in asian rhinoplasty.

    Science.gov (United States)

    Jang, Yong Ju; Yi, Jong Sook

    2014-04-01

    Asian patients present with relatively poorly developed dorsal and tip height and thicker skin, so augmentation rhinoplasty is the most commonly performed rhinoplasty procedure. Tip surgery using autologous cartilage followed by dorsal augmentation using an alloplastic implant material is the most widely performed surgical procedure for augmentation rhinoplasty on Asian patients. Cartilage tip grafting procedures, including shield grafting, multilayer tip grafting, onlay grafting, and modified vertical dome division, are key maneuvers for building up and providing better definition on a relatively poorly developed Asian tip. When performing primary cosmetic dorsal augmentation using alloplastic implants, the implant material should be selected according to the surgeon's experience, the pros and cons of available dorsal implant materials, and host factors such as skin thickness, associated deformities, and aesthetic goals. The costal cartilage is best reserved for difficult revisions, except in a limited number of primary cases who present with a very poorly developed nasal skeleton and thick skin. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  5. Fabrication of a compliant phantom of the human aortic arch for use in Particle Image Velocimetry (PIV experimentation

    Directory of Open Access Journals (Sweden)

    Hütter Larissa

    2016-09-01

    Full Text Available Compliant phantoms of the human aortic arch can mimic patient specific cardiovascular dysfunctions in vitro. Hence, phantoms may enable elucidation of haemodynamic disturbances caused by aortic dysfunction. This paper describes the fabrication of a thin-walled silicone phantom of the human ascending aorta and brachiocephalic artery. The model geometry was determined via a meta-analysis and modelled in SolidWorks before 3D printing. The solid model surface was smoothed and scanned with a 3D scanner. An offset outer mould was milled from Ebalta S-Model board. The final phantom indicated that ABS was a suitable material for the internal model, the Ebalta S-Model board yielded a rough external surface. Co-location of the moulds during silicone pour was insufficient to enable consistent wall thickness. The resulting phantom was free of air bubbles but did not have the desired wall thickness consistency.

  6. Initial investigation of a novel light-scattering gel phantom for evaluation of optical CT scanners for radiotherapy gel dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Bosi, Stephen [Institute of Medical Physics, School of Physics, University of Sydney, NSW 2006 (Australia); Naseri, Pourandokht [Institute of Medical Physics, School of Physics, University of Sydney, NSW 2006 (Australia); Puran, Alicia [Institute of Medical Physics, School of Physics, University of Sydney, NSW 2006 (Australia); Davies, Justin [Institute of Medical Physics, School of Physics, University of Sydney, NSW 2006 (Australia); Baldock, Clive [Institute of Medical Physics, School of Physics, University of Sydney, NSW 2006 (Australia)

    2007-05-21

    There is a need for stable gel materials for phantoms used to validate optical computerized tomography (CT) scanners used in conjunction with radiation-induced polymerizing gel dosimeters. Phantoms based on addition of light-absorbing dyes to gelatine to simulate gel dosimeters have been employed. However, to more accurately simulate polymerizing gels one requires phantoms that employ light-scattering colloidal suspensions added to the gel. In this paper, we present the initial results of using an optical CT scanner to evaluate a novel phantom in which radiation-exposed polymer gels are simulated by the addition of colloidal suspensions of varying turbidity. The phantom may be useful as a calibration transfer standard for polymer gel dosimeters. The tests reveal some phenomena peculiar to light-scattering gels that need to be taken into account when calibrating polymer gel dosimeters.

  7. The Psychological and Cultural Aspects of Political Participation of Asian Americans.

    Science.gov (United States)

    Jo, Moon H.

    While Asians in the United States continue to experience the discriminatory barriers that other minorities face, the myth that Asian Americans are a well-adjusted model minority has resulted in public neglect of the problems of this group. To a significant extent, the myth arises from the fact that Chinese, Japanese, and other Asian groups have…

  8. Support for Conference Entitled The Fifth PHANTOM Users Group Workshop

    National Research Council Canada - National Science Library

    Reinig, Karl

    2001-01-01

    The Fifth PHANToM Users Group (PUG2000) brought together, in an intimate setting, participants who are actively engaged in making computer haptics practical and useful through the use of the PHANTOM Haptic Interface...

  9. Effect of the Scattering Radiation in Air and Two Type of Slap Phantom between PMMA and the ISO Water Phantom for Personal Dosimeters Calibration

    Science.gov (United States)

    Kamwang, N.; Rungseesumran, T.; Saengchantr, D.; Monthonwattana, S.; Pungkun, V.

    2017-06-01

    The calibration of personal dosimeter to determine the quantities of the personal dose equivalent, Hp(d), is required to be placed on a suitable phantom in order to provide a reasonable approximation to the radiation backscattering properties as equivalent as part of body. The dosimeter which is worn on the trunk usually calibrated with slap phantom which recommended in ICRU 47 with dimension of 30 cm (w) x 30 cm (h) x 15 cm (t) PMMA slab phantom to achieve uniformity in calibration procedures, on the other hand the International Organization for Standardization (ISO), ISO 4037-3, proposed the ISO water slap phantom, with PMMA walls, same dimension but different wall thickness (front wall 2.5 mm and other side wall 10 mm thick) and fill with water. However, some laboratories are still calibrating a personal dosimeter in air in term of ambient dose equivalent, H*(d). This research study the effect of the scattering radiation in two type of those slap phantoms and in air, to calibrate two type of OSL (XA and LA) and electronic personal dosimeters. The X-ray and Cs-137 radiation field with the energy range from 33 to 662 keV were used. The results of this study will be discussed.

  10. Phantom breast sensations are frequent after mastectomy

    DEFF Research Database (Denmark)

    Hansen, Dorthe Marie Helbo; Kehlet, Henrik; Gärtner, Rune

    2011-01-01

    Phantom breast sensation (PBS) following mastectomy has been recognized for many years. PBS is a feeling that the removed breast is still there. The reported prevalence and risk factors have not been established in large well-defined patient series. The purpose of this study was to examine...... the prevalence of PBS following mastectomy and associated risk factors....

  11. Phantoms for Radiation Measurements of Mobile Phones

    DEFF Research Database (Denmark)

    Pedersen, Gert Frølund

    2001-01-01

    Measurements of radiation efficiency for a handheld phone equipped with a patch and a helical antenna operated near the human user have been performed. Both measurements include a simple head plus hand phantom and live persons are considered. The position of the hand on the phone is found...

  12. Phantom breast sensations are frequent after mastectomy

    DEFF Research Database (Denmark)

    Hansen, Dorthe Marie Helbo; Kehlet, Henrik; Gærtner, Rune

    2011-01-01

    Phantom breast sensation (PBS) following mastectomy has been recognized for many years. PBS is a feeling that the removed breast is still there. The reported prevalence and risk factors have not been established in large well-defined patient series. The purpose of this study was to examine...

  13. New eye phantom for ophthalmic surgery

    Science.gov (United States)

    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.

  14. Cortical Depression and Potentiation: Basic Mechanisms for Phantom Pain

    OpenAIRE

    Zhuo, Min

    2012-01-01

    People experience the feeling of the missing body part long after it has been removed after amputation are known as phantom limb sensations. These sensations can be painful, sometimes becoming chronic and lasting for several years (or called phantom pain). Medical treatment for these individuals is limited. Recent neurobiological investigations of brain plasticity after amputation have revealed new insights into the changes in the brain that may cause phantom limb sensations and phantom pain....

  15. Multilayered tissue mimicking skin and vessel phantoms with tunable mechanical, optical, and acoustic properties

    Science.gov (United States)

    Chen, Alvin I.; Balter, Max L.; Chen, Melanie I.; Gross, Daniel; Alam, Sheikh K.; Maguire, Timothy J.; Yarmush, Martin L.

    2016-01-01

    Purpose: This paper describes the design, fabrication, and characterization of multilayered tissue mimicking skin and vessel phantoms with tunable mechanical, optical, and acoustic properties. The phantoms comprise epidermis, dermis, and hypodermis skin layers, blood vessels, and blood mimicking fluid. Each tissue component may be individually tailored to a range of physiological and demographic conditions. Methods: The skin layers were constructed from varying concentrations of gelatin and agar. Synthetic melanin, India ink, absorbing dyes, and Intralipid were added to provide optical absorption and scattering in the skin layers. Bovine serum albumin was used to increase acoustic attenuation, and 40 μm diameter silica microspheres were used to induce acoustic backscatter. Phantom vessels consisting of thin-walled polydimethylsiloxane tubing were embedded at depths of 2–6 mm beneath the skin, and blood mimicking fluid was passed through the vessels. The phantoms were characterized through uniaxial compression and tension experiments, rheological frequency sweep studies, diffuse reflectance spectroscopy, and ultrasonic pulse-echo measurements. Results were then compared to in vivo and ex vivo literature data. Results: The elastic and dynamic shear behavior of the phantom skin layers and vessel wall closely approximated the behavior of porcine skin tissues and human vessels. Similarly, the optical properties of the phantom tissue components in the wavelength range of 400–1100 nm, as well as the acoustic properties in the frequency range of 2–9 MHz, were comparable to human tissue data. Normalized root mean square percent errors between the phantom results and the literature reference values ranged from 1.06% to 9.82%, which for many measurements were less than the sample variability. Finally, the mechanical and imaging characteristics of the phantoms were found to remain stable after 30 days of storage at 21 °C. Conclusions: The phantoms described in this

  16. Thrombolysis for acute ischaemic stroke with alteplase in an Asian population: results of the multicenter, multinational Safe Implementation of Thrombolysis in Stroke-Non-European Union World (SITS-NEW).

    Science.gov (United States)

    Rha, Joung-Ho; Shrivastava, Vasantha Padma; Wang, Yongjun; Lee, Kim En; Ahmed, Niaz; Bluhmki, Erich; Hermansson, Karin; Wahlgren, Nils

    2014-10-01

    Safe Implementation of Thrombolysis in Stroke-Non-European Union World was a multinational, prospective, open, monitored, observational study of intravenous alteplase as thrombolytic therapy in clinical practice. Safe Implementation of Thrombolysis in Stroke-Non-European Union World was required to assess the safety of alteplase in an Asian population by comparison with results from the European Safe Implementation of Thrombolysis in Stroke-Monitoring Study and pooled results from randomized controlled trials. To evaluate the efficacy and safety of intravenous alteplase (0·9 mg/kg) as thrombolytic therapy within three-hours of onset of acute ischaemic stroke in an Asian population. The 591 patients included were treated at 48 centers in four countries (South Korea, China, India, and Singapore) between 2006 and 2008. Primary outcomes were symptomatic (deterioration in National Institutes of Health Stroke Scale score ≥4 or death within the first 24 h) intracerebral haemorrhage type 2 22-36 h after the thrombolysis and mortality at three-month follow-up. The secondary outcome was functional independence (modified Rankin Scale score 0-2) at three-months. Results were compared with those from Safe Implementation of Thrombolysis in Stroke-Monitoring Study (n = 6483) and pooled results of patients (n = 415) who received intravenous alteplase (0·9 mg/kg) zero- to three-hours from onset of stroke symptoms in four randomized controlled trials (National Institute of Neurological Disorders and Stroke A and B, Altephase Thrombolysis for Acute Noninterventional Therapy in Ischaemic Stroke, and European Cooperative Acute Stroke Study II). Results are presented as Safe Implementation of Thrombolysis in Stroke-Non-European Union World vs. Safe Implementation of Thrombolysis in Stroke-Monitoring Study vs. pooled randomized controlled trials. Median age was 64 vs. 68 vs. 70 years, National Institutes of Health Stroke Scale score at baseline was 12 vs. 12 vs. 13

  17. Motorized fusion guided prostate biopsy: phantom study

    Science.gov (United States)

    Seifabadi, Reza; Xu, Sheng; Aalamifar, Fereshteh; Pinto, Peter; Wood, Bradford J.

    2017-03-01

    Purpose: Fusion of Magnetic Resonance Imaging (MRI) with intraoperative real-time Ultrasound (US) during prostate biopsy has significantly improved the sensitivity of transrectal ultrasound (TRUS) guided cancer detection. Currently, sweeping of the TRUS probe to build a 3D volume as part of the fusion process and the TRUS probe manipulation for needle guidance are both done manually. A motorized, joystick controlled, probe holder was custom fabricated that can potentially reduce inter-operator variability, provide standardization of needle placement, improve repeatability and uniformity of needle placement, which may have impacts upon the learning curve after clinical deployment of this emerging approach. Method: a 2DOF motorized probe holder was designed to provide translation and rotation of a triplane TRUS end firing probe for prostate biopsy. The probe holder was joystick controlled and can assist manipulation of the probe during needle insertion as well as in acquiring a smoother US 2D to 3D sweep in which the 3D US volume for fusion is built. A commercial MRI-US fusion platform was used. Three targets were specified on MR image of a commercial prostate phantom. After performing the registration, two operators performed targeting, once manually and once with the assistance of the motorized probe holder. They repeated these tasks 5 times resulting in a total of 30 targeting events. Time of completion and mechanical error i.e. distance of the target from the needle trajectory in the software user interface were measured. Repeatability in reaching a given target in a systematic and consistent way was measured using a scatter plot showing all targets in the US coordinate system. Pearson product-moment correlation coefficient (PPMCC) was used to demonstrate the probe steadiness during targeting. Results: the completion time was 25+/-17 sec, 25+/-24 sec, and 27+/-15 sec for free hand and 24+/-10 sec, 22.5+/-10 sec, and 37+/-10 sec for motorized insertion, for target

  18. 21 CFR 892.1380 - Nuclear flood source phantom.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nuclear flood source phantom. 892.1380 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1380 Nuclear flood source phantom. (a) Identification. A nuclear flood source phantom is a device that consists of a radiolucent container filled with a...

  19. 21 CFR 892.1420 - Radionuclide test pattern phantom.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radionuclide test pattern phantom. 892.1420... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1420 Radionuclide test pattern phantom. (a) Identification. A radionuclide test pattern phantom is a device that consists of an arrangement...

  20. 21 CFR 892.1370 - Nuclear anthropomorphic phantom.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 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 a...

  1. A Novel 141Ce-Based Flood Field Phantom: Assessment of Suitability for Daily Uniformity Testing in a Clinical Nuclear Medicine Department.

    Science.gov (United States)

    Jha, Ashish Kumar; Mithun, Sneha; Chauhan, Manoj H; Purandare, Nilendu; Shah, Sneha; Agrawal, Archi; Saxena, Sanjay Kumar; Dash, Ashutosh; Rangarajan, Venkatesh

    2017-09-01

    Daily quality control testing of a γ-camera is of the utmost importance in assessing whether the camera is suitable for clinical use. The aim of our study was to assess the suitability of a fillable 141Ce-based flood field phantom developed in-house for daily quality control testing of γ-cameras. Methods: Daily uniformity testing was performed for 113 d using the fillable 141Ce phantom and a commercially available sheet-type 57Co phantom, and the results were compared. Results: The average integral uniformity obtained by the 141Ce and 57Co phantoms was 3.24% and 2.72%, respectively, for detector 1 and 3.31% and 2.78%, respectively, for detector 2. Conclusion: The 141Ce phantom we developed is a suitable alternative to the commercially available 57Co phantom. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

  2. Survey of phantom limb pain, phantom sensation and stump pain in Cambodian and New Zealand amputees.

    Science.gov (United States)

    Byrne, Kelly Patrick Anthony

    2011-05-01

    The primary objective of this study is to compare the prevalence of phantom limb pain in New Zealand and Cambodian amputees and to assess the demographics of a sample of amputees from these two countries. All participants were interviewed using a 12-question survey that covered demographic data and reason for amputation and assessed the presence of phantom limb sensation, phantom limb pain, and stump pain. Amputees attending an artificial limb center in Cambodia were approached and interviewed in person. New Zealand amputees attending the Waikato artificial limb center were randomly selected and interviewed by phone. There was no statistically significant difference in phantom limb sensation, phantom limb pain, or stump pain between the two groups. There was a much higher unemployment rate in the Cambodian amputees. There were no other statistically significant differences between the groups Despite very different environments, there was no difference in the phantom limb pain between the groups. One possible explanation is that the severity of neurological injury associated with amputation overrides all the other risk factors that influence the development of other chronic pain syndromes. Wiley Periodicals, Inc.

  3. Higher bone resorption excretion in South Asian women vs. White Caucasians and increased bone loss with higher seasonal cycling of vitamin D: Results from the D-FINES cohort study.

    Science.gov (United States)

    Darling, A L; Hart, K H; Gossiel, F; Robertson, F; Hunt, J; Hill, T R; Johnsen, S; Berry, J L; Eastell, R; Vieth, R; Lanham-New, S A

    2017-05-01

    Few data exist on bone turnover in South Asian women and it is not well elucidated as to whether Western dwelling South Asian women have different bone resorption levels to that of women from European ethnic backgrounds. This study assessed bone resorption levels in UK dwelling South Asian and Caucasian women as well as evaluating whether seasonal variation in 25-hydroxyvitamin D [25(OH)D] is associated with bone resorption in either ethnic group. Data for seasonal measures of urinary N-telopeptide of collagen (uNTX) and serum 25(OH)D were analysed from n=373 women (four groups; South Asian postmenopausal n=44, South Asian premenopausal n=50, Caucasian postmenopausal n=144, Caucasian premenopausal n=135) (mean (±SD) age 48 (14) years; age range 18-79years) who participated in the longitudinal D-FINES (Diet, Food Intake, Nutrition and Exposure to the Sun in Southern England) cohort study (2006-2007). A mixed between-within subjects ANOVA (n=192) showed a between subjects effect of the four groups (PD was predictive of uNTX, with estimate (SD)=0.213 (0.015) and 95% CI (0.182, 0.245; PD, adjusted for overall 25(OH)D concentration, showed increased levels of uNTX. Although the effect size was smaller than for the amplitude/mesor ratio, the mesor for 25(OH)D concentration was also predictive of uNTX, with estimate (SD)=-0.035 (0.004), and 95% CI (-0.043, -0.028; PD concentration showed an increased bone resorption, an association which was larger than that of the 25(OH)D yearly average, suggesting it may be as important clinically to ensure a stable and steady 25(OH)D concentration, as well as one that is high enough to be optimal for bone health. Copyright © 2017 Elsevier Inc. All rights reserved.

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

    Science.gov (United States)

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

    2010-07-01

    Carlo radiation transport simulations. This paper also compares absorbed organ doses for the RPI-AM-5th-height and -weight percentile phantom (165 cm in height and 56 kg in weight) and the RPI-AM-95th-height and -weight percentile phantom (188 cm in height and 110 kg in weight) with those for the RPI-AM-50th-height and -weight percentile phantom (176 cm in height and 73 kg in weight) from exposures to 0.5 MeV external photon beams. The results suggest a general finding that the phantoms representing a slimmer and shorter individual male received higher absorbed organ doses because of lesser degree of photon attenuation due to smaller amount of body fat. In particular, doses to the prostate and adrenal in the RPI-AM-5th-height and -weight percentile phantom is about 10% greater than those in the RPI-AM-50th-height and -weight percentile phantom approximating the ICRP Reference Man. On the other hand, the doses to the prostate and adrenal in the RPI-AM-95th-height and -weight percentile phantom are approximately 20% greater than those in the RPI-AM-50th-height and -weight percentile phantom. Although this study only considered the photon radiation of limited energies and irradiation geometries, the potential to improve the organ dose accuracy using the deformable phantom technology is clearly demonstrated.

  5. Comparison of the automated evaluation of phantom mama in digital and digitalized images; Comparacao da avaliacao automatizada do phantom mama em imagens digitais e digitalizadas

    Energy Technology Data Exchange (ETDEWEB)

    Santana, Priscila do Carmo, E-mail: pcs@cdtn.b [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear. Programa de Pos-Graduacao em Ciencias e Tecnicas Nucleares; Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Fac. de Medicina. Dept. de Propedeutica Complementar; Gomes, Danielle Soares; Oliveira, Marcio Alves; Nogueira, Maria do Socorro, E-mail: mnogue@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2011-07-01

    Mammography is an essential tool for diagnosis and early detection of breast cancer if it is provided as a very good quality service. The process of evaluating the quality of radiographic images in general, and mammography in particular, can be much more accurate, practical and fast with the help of computer analysis tools. This work compare the automated methodology for the evaluation of scanned digital images the phantom mama. By applied the DIP method techniques was possible determine geometrical and radiometric images evaluated. The evaluated parameters include circular details of low contrast, contrast ratio, spatial resolution, tumor masses, optical density and background in Phantom Mama scanned and digitized images. The both results of images were evaluated. Through this comparison was possible to demonstrate that this automated methodology is presented as a promising alternative for the reduction or elimination of subjectivity in both types of images, but the Phantom Mama present insufficient parameters for spatial resolution evaluation. (author)

  6. An externally and internally deformable, programmable lung motion phantom

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, Yam; Sawant, Amit, E-mail: amit.sawant@utsouthwestern.edu [UT Southwestern Medical Center, University of Texas, Dallas, Texas 75390 (United States)

    2015-05-15

    Purpose: Most clinically deployed strategies for respiratory motion management in lung radiotherapy (e.g., gating and tracking) use external markers that serve as surrogates for tumor motion. However, typical lung phantoms used to validate these strategies are based on a rigid exterior and a rigid or a deformable-interior. Such designs do not adequately represent respiration because the thoracic anatomy deforms internally as well as externally. In order to create a closer approximation of respiratory motion, the authors describe the construction and experimental testing of an externally as well as internally deformable, programmable lung phantom. Methods: The outer shell of a commercially available lung phantom (RS-1500, RSD, Inc.) was used. The shell consists of a chest cavity with a flexible anterior surface, and embedded vertebrae, rib-cage and sternum. A custom-made insert was designed using a piece of natural latex foam block. A motion platform was programmed with sinusoidal and ten patient-recorded lung tumor trajectories. The platform was used to drive a rigid foam “diaphragm” that compressed/decompressed the phantom interior. Experimental characterization comprised of determining the reproducibility and the external–internal correlation of external and internal marker trajectories extracted from kV x-ray fluoroscopy. Experiments were conducted to illustrate three example applications of the phantom—(i) validating the geometric accuracy of the VisionRT surface photogrammetry system; (ii) validating an image registration tool, NiftyReg; and (iii) quantifying the geometric error due to irregular motion in four-dimensional computed tomography (4DCT). Results: The phantom correctly reproduced sinusoidal and patient-derived motion, as well as realistic respiratory motion-related effects such as hysteresis. The reproducibility of marker trajectories over multiple runs for sinusoidal as well as patient traces, as characterized by fluoroscopy, was within 0

  7. Finite-element modeling of compression and gravity on a population of breast phantoms for multimodality imaging simulation.

    Science.gov (United States)

    Sturgeon, Gregory M; Kiarashi, Nooshin; Lo, Joseph Y; Samei, E; Segars, W P

    2016-05-01

    The authors are developing a series of computational breast phantoms based on breast CT data for imaging research. In this work, the authors develop a program that will allow a user to alter the phantoms to simulate the effect of gravity and compression of the breast (craniocaudal or mediolateral oblique) making the phantoms applicable to multimodality imaging. This application utilizes a template finite-element (FE) breast model that can be applied to their presegmented voxelized breast phantoms. The FE model is automatically fit to the geometry of a given breast phantom, and the material properties of each element are set based on the segmented voxels contained within the element. The loading and boundary conditions, which include gravity, are then assigned based on a user-defined position and compression. The effect of applying these loads to the breast is computed using a multistage contact analysis in FEBio, a freely available and well-validated FE software package specifically designed for biomedical applications. The resulting deformation of the breast is then applied to a boundary mesh representation of the phantom that can be used for simulating medical images. An efficient script performs the above actions seamlessly. The user only needs to specify which voxelized breast phantom to use, the compressed thickness, and orientation of the breast. The authors utilized their FE application to simulate compressed states of the breast indicative of mammography and tomosynthesis. Gravity and compression were simulated on example phantoms and used to generate mammograms in the craniocaudal or mediolateral oblique views. The simulated mammograms show a high degree of realism illustrating the utility of the FE method in simulating imaging data of repositioned and compressed breasts. The breast phantoms and the compression software can become a useful resource to the breast imaging research community. These phantoms can then be used to evaluate and compare imaging

  8. Feasibility of reducing differences in estimated doses in nuclear medicine between a patient-specific and a reference phantom.

    Science.gov (United States)

    Zvereva, Alexandra; Schlattl, Helmut; Zankl, Maria; Becker, Janine; Petoussi-Henss, Nina; Yeom, Yeon Soo; Kim, Chan Hyeong; Hoeschen, Christoph; Parodi, Katia

    2017-07-01

    The feasibility of reducing the differences between patient-specific internal doses and doses estimated using reference phantoms was evaluated. Relatively simple adjustments to a polygon-surface ICRP adult male reference phantom were applied to fit selected individual dimensions using the software Rhinoceros®4.0. We tested this approach on two patient-specific phantoms: the biggest and the smallest phantoms from the Helmholtz Zentrum München library. These phantoms have unrelated anatomy and large differences in body-mass-index. Three models approximating each patient's anatomy were considered: the voxel and the polygon-surface ICRP adult male reference phantoms and the adjusted polygon-surface reference phantom. The Specific Absorbed Fractions (SAFs) for internal photon and electron sources were calculated with the Monte Carlo code EGSnrc. Employing the time-integrated activity coefficients of a radiopharmaceutical (S)-4-(3-(18)F-fluoropropyl)-l-glutamic acid and the calculated SAFs, organ absorbed-dose coefficients were computed following the formalism promulgated by the Committee on Medical Internal Radiation Dose. We compared the absorbed-dose coefficients between each patient-specific phantom and other models considered with emphasis on the cross-fire component. The corresponding differences for most organs were notably lower for the adjusted reference models compared to the case when reference models were employed. Overall, the proposed approach provided reliable dose estimates for both tested patient-specific models despite the pronounced differences in their anatomy. To capture the full range of inter-individual anatomic variability more patient-specific phantoms are required. The results of this test study suggest a feasibility of estimating patient-specific doses within a relative uncertainty of 25% or less using adjusted reference models, when only simple phantom scaling is applied. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by

  9. Preparation and fabrication of a full-scale, sagittal-sliced, 3D-printed, patient-specific radiotherapy phantom.

    Science.gov (United States)

    Craft, Daniel F; Howell, Rebecca M

    2017-09-01

    Patient-specific 3D-printed phantoms have many potential applications, both research and clinical. However, they have been limited in size and complexity because of the small size of most commercially available 3D printers as well as material warping concerns. We aimed to overcome these limitations by developing and testing an effective 3D printing workflow to fabricate a large patient-specific radiotherapy phantom with minimal warping errors. In doing so, we produced a full-scale phantom of a real postmastectomy patient. We converted a patient's clinical CT DICOM data into a 3D model and then sliced the model into eleven 2.5-cm-thick sagittal slices. The slices were printed with a readily available thermoplastic material representing all body tissues at 100% infill, but with air cavities left open. Each slice was printed on an inexpensive and commercially available 3D printer. Once the printing was completed, the slices were placed together for imaging and verification. The original patient CT scan and the assembled phantom CT scan were registered together to assess overall accuracy. The materials for the completed phantom cost $524. The printed phantom agreed well with both its design and the actual patient. Individual slices differed from their designs by approximately 2%. Registered CT images of the assembled phantom and original patient showed excellent agreement. Three-dimensional printing the patient-specific phantom in sagittal slices allowed a large phantom to be fabricated with high accuracy. Our results demonstrate that our 3D printing workflow can be used to make large, accurate, patient-specific phantoms at 100% infill with minimal material warping error. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  10. The threshold contrast thickness evaluated with different CDMAM phantoms and software

    Directory of Open Access Journals (Sweden)

    Fabiszewska Ewa

    2016-03-01

    Full Text Available The image quality in digital mammography is described by specifying the thickness and diameter of disks with threshold visibility. The European Commission recommends the CDMAM phantom as a tool to evaluate threshold contrast visibility in digital mammography [1, 2]. Inaccuracy of the manufacturing process of CDMAM 3.4 phantoms (Artinis Medical System BV, as well as differences between software used to analyze the images, may lead to discrepancies in the evaluation of threshold contrast visibility. The authors of this work used three CDMAM 3.4 phantoms with serial numbers 1669, 1840, and 1841 and two mammography systems of the same manufacturer with an identical types of detectors. The images were analyzed with EUREF software (version 1.5.5 with CDCOM 1.6. exe file and Artinis software (version 1.2 with CDCOM 1.6. exe file. The differences between the observed thicknesses of the threshold contrast structures, which were caused by differences between the CDMAM 3.4 phantoms, were not reproduced in the same way on two mammography units of the same type. The thickness reported by the Artinis software (version 1.2 with CDCOM 1.6. exe file was generally greater than the one determined by the EUREF software (version 1.5.5 with CDCOM 1.6. exe file, but the ratio of the results depended on the phantom and diameter of the structure. It was not possible to establish correction factors, which would allow correction of the differences between the results obtained for different CDMAM 3.4 phantoms, or to correct the differences between software. Great care must be taken when results of the tests performed with different CDMAM 3.4 phantoms and with different software application are interpreted.

  11. Use of computational fluid dynamics in the design of dynamic contrast enhanced imaging phantoms.

    Science.gov (United States)

    Hariharan, Prasanna; Freed, Melanie; Myers, Matthew R

    2013-09-21

    Phantoms for dynamic contrast enhanced (DCE) imaging modalities such as DCE computed tomography (DCE-CT) and DCE magnetic resonance imaging (DCE-MRI) are valuable tools for evaluating and comparing imaging systems. It is important for the contrast-agent distribution within the phantom to possess a time dependence that replicates a curve observed clinically, known as the 'tumor-enhancement curve'. It is also important for the concentration field within the lesion to be as uniform as possible. This study demonstrates how computational fluid dynamics (CFD) can be applied to achieve these goals within design constraints. The distribution of the contrast agent within the simulated phantoms was investigated in relation to the influence of three factors of the phantom design. First, the interaction between the inlets and the uniformity of the contrast agent within the phantom was modeled. Second, pumps were programmed using a variety of schemes and the resultant dynamic uptake curves were compared to tumor-enhancement curves obtained from clinical data. Third, the effectiveness of pulsing the inlet flow rate to produce faster equilibration of the contrast-agent distribution was quantified. The models employed a spherical lesion and design constraints (lesion diameter, inlet-tube size and orientation, contrast-agent flow rates and fluid properties) taken from a recently published DCE-MRI phantom study. For DCE-MRI in breast cancer detection, where the target tumor-enhancement curve varies on the scale of hundreds of seconds, optimizing the number of inlet tubes and their orientation was found to be adequate for attaining concentration uniformity and reproducing the target tumor-enhancement curve. For DCE-CT in liver tumor detection, where the tumor-enhancement curve varies on a scale of tens of seconds, the use of an iterated inlet condition (programmed into the pump) enabled the phantom to reproduce the target tumor-enhancement curve within a few per cent beyond about 6

  12. South Asian Cluster

    Directory of Open Access Journals (Sweden)

    Ionel Sergiu Pirju

    2014-12-01

    Full Text Available This article aims at presenting the South Asian cluster composed of India, Indonesia, Iran and Malaysia, the intercultural values that characterizes it, the supported leadership style and tracing the main macroeconomic considerations which characterizes them. The research is synchronic, analysing the contemporary situation of these countries without reference to their evolution in time, by using the positivist paradigm that explains the reality at one point. It will be analysed the overall cluster with the existing interactions between the countries that composes it, while the article being one of information will avoid building recommendation, or new theories.

  13. Do Caucasian and Asian clocks tick differently?

    Directory of Open Access Journals (Sweden)

    A.A. Barbosa

    Full Text Available The Period 3 and Clock genes are important components of the mammalian molecular circadian system. Studies have shown association between polymorphisms in these clock genes and circadian phenotypes in different populations. Nevertheless, differences in the pattern of allele frequency and genotyping distribution are systematically observed in studies with different ethnic groups. To investigate and compare the pattern of distribution in a sample of Asian and Caucasian populations living in Brazil, we evaluated two well-studied polymorphisms in the clock genes: a variable number of tandem repeats (VNTR in PER3 and a single nucleotide polymorphism (SNP in CLOCK. The aim of this investigation was to search for clues about human evolutionary processes related to circadian rhythms. We selected 109 Asian and 135 Caucasian descendants. The frequencies of the shorter allele (4 repeats in the PER3 gene and the T allele in the CLOCK gene among Asians (0.86 and 0.84, respectively were significantly higher than among Caucasians (0.69 and 0.71, respectively. Our results directly confirmed the different distribution of these polymorphisms between the Asian and Caucasian ethnic groups. Given the genetic differences found between groups, two points became evident: first, ethnic variations may have implications for the interpretation of results in circadian rhythm association studies, and second, the question may be raised about which evolutionary conditions shaped these genetic clock variations.

  14. Do Caucasian and Asian clocks tick differently?

    Science.gov (United States)

    Barbosa, A A; Pedrazzoli, M; Koike, B D V; Tufik, S

    2010-01-01

    The Period 3 and Clock genes are important components of the mammalian molecular circadian system. Studies have shown association between polymorphisms in these clock genes and circadian phenotypes in different populations. Nevertheless, differences in the pattern of allele frequency and genotyping distribution are systematically observed in studies with different ethnic groups. To investigate and compare the pattern of distribution in a sample of Asian and Caucasian populations living in Brazil, we evaluated two well-studied polymorphisms in the clock genes: a variable number of tandem repeats (VNTR) in PER3 and a single nucleotide polymorphism (SNP) in CLOCK. The aim of this investigation was to search for clues about human evolutionary processes related to circadian rhythms. We selected 109 Asian and 135 Caucasian descendants. The frequencies of the shorter allele (4 repeats) in the PER3 gene and the T allele in the CLOCK gene among Asians (0.86 and 0.84, respectively) were significantly higher than among Caucasians (0.69 and 0.71, respectively). Our results directly confirmed the different distribution of these polymorphisms between the Asian and Caucasian ethnic groups. Given the genetic differences found between groups, two points became evident: first, ethnic variations may have implications for the interpretation of results in circadian rhythm association studies, and second, the question may be raised about which evolutionary conditions shaped these genetic clock variations.

  15. Do Caucasian and Asian clocks tick differently?

    Directory of Open Access Journals (Sweden)

    A.A. Barbosa

    2010-01-01

    Full Text Available The Period 3 and Clock genes are important components of the mammalian molecular circadian system. Studies have shown association between polymorphisms in these clock genes and circadian phenotypes in different populations. Nevertheless, differences in the pattern of allele frequency and genotyping distribution are systematically observed in studies with different ethnic groups. To investigate and compare the pattern of distribution in a sample of Asian and Caucasian populations living in Brazil, we evaluated two well-studied polymorphisms in the clock genes: a variable number of tandem repeats (VNTR in PER3 and a single nucleotide polymorphism (SNP in CLOCK. The aim of this investigation was to search for clues about human evolutionary processes related to circadian rhythms. We selected 109 Asian and 135 Caucasian descendants. The frequencies of the shorter allele (4 repeats in the PER3 gene and the T allele in the CLOCK gene among Asians (0.86 and 0.84, respectively were significantly higher than among Caucasians (0.69 and 0.71, respectively. Our results directly confirmed the different distribution of these polymorphisms between the Asian and Caucasian ethnic groups. Given the genetic differences found between groups, two points became evident: first, ethnic variations may have implications for the interpretation of results in circadian rhythm association studies, and second, the question may be raised about which evolutionary conditions shaped these genetic clock variations.

  16. Immunizations and Asians and Pacific Islanders

    Science.gov (United States)

    ... and Data > Minority Population Profiles > Asian American > Immunizations Immunizations and Asians and Pacific Islanders Asian/Pacific Islander ... 35 months reached the Healthy People goal for immunizations for hepatitis B, MMR (measles-mumps-rubella), polio ...

  17. Fabrication of Two Flow Phantoms for Doppler Ultrasound Imaging.

    Science.gov (United States)

    Zhou, Xiaowei; Kenwright, David A; Wang, Shiying; Hossack, John A; Hoskins, Peter R

    2017-01-01

    Flow phantoms are widely used in studies associated with Doppler ultrasound measurements, acting as an effective experimental validation system in cardiovascular-related research and in new algorithm/instrumentation development. The development of materials that match the acoustic and mechanical properties of the vascular system is of great interest while designing flow phantoms. Although recipes that meet the flow phantom standard defined by the International Electrotechnical Commission 61685 are already available in the literature, the standard procedure for material preparations and phantom fabrications has not been well established. In this paper, two types of flow phantoms, with and without blood vessel mimic, are described in detail in terms of the material preparation and phantom fabrication. The phantom materials chosen for the two phantoms are from published phantom studies, and their physical properties have been investigated previously. Both the flow phantoms have been scanned by ultrasound scanners and images from different modes are presented. These phantoms may be used in the validation and characterization of Doppler ultrasound measurements in blood vessels with a diameter above 1 mm.

  18. Pipe Phantoms With Applications in Molecular Imaging and System Characterization.

    Science.gov (United States)

    Wang, Shiying; Herbst, Elizabeth B; Pye, Stephen D; Moran, Carmel M; Hossack, John A

    2017-01-01

    Pipe (vessel) phantoms mimicking human tissue and blood flow are widely used for cardiovascular related research in medical ultrasound. Pipe phantom studies require the development of materials and liquids that match the acoustic properties of soft tissue, blood vessel wall, and blood. Over recent years, pipe phantoms have been developed to mimic the molecular properties of the simulated blood vessels. In this paper, the design, construction, and functionalization of pipe phantoms are introduced and validated for applications in molecular imaging and ultrasound imaging system characterization. There are three major types of pipe phantoms introduced: 1) a gelatin-based pipe phantom; 2) a polydimethylsiloxane-based pipe phantom; and 3) the "Edinburgh pipe phantom." These phantoms may be used in the validation and assessment of the dynamics of microbubble-based contrast agents and, in the case of a small diameter tube phantom, for assessing imaging system spatial resolution/contrast performance. The materials and procedures required to address each of the phantoms are described.

  19. An EGS4 user code with voxel geometry and a voxel phantom generation system

    Energy Technology Data Exchange (ETDEWEB)

    Funabiki, J.; Terabe, M. [Mitsubishi Research Institute, Inc., Tokyo (Japan); Zankl, M. [GSF, Neuherberg, Oberschleissheim (Germany); Koga, S. [Fujita Health Univ., Toyoake, Aichi (Japan); Saito, K. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2000-12-01

    An EGS4 (Electron Gamma Shower Version 4) user code with voxel geometry (the UCPIXEL code) has been developed in order to make accurate dose evaluation by using human voxel phantoms. The voxel data have a format devised by GSF. This format can compress so large amount of high-resolution voxel data that required memory for computation is greatly reduced. UCPIXEL can treat 8 basic irradiation geometries (AP, PA, RLAT, LLAT, ROT, ISO, AB, BA) and cylindrical pseudo-environmental radiation source with arbitrary size, energy and directional distribution. In addition, UCPIXEL can model contaminated soil with arbitrary area and depth under a phantom and radiation from the soil. By using a post-processor, effective dose equivalent, effective dose and organ doses can be evaluated from the output of UCPIXEL. Preliminary results of effective dose calculated by using UCPIXEL for a Japanese voxel phantom are demonstrated and compared with the previous results for MIRD-type phantoms. We have also developed an intelligent system which automatically constructs a voxel phantom from CT data. We introduce this system and preliminary results are shown. (author)

  20. Real Time Target Tracking in a Phantom Using Ultrasonic Imaging

    Science.gov (United States)

    Xiao, X.; Corner, G.; Huang, Z.

    In this paper we present a real-time ultrasound image guidance method suitable for tracking the motion of tumors. A 2D ultrasound based motion tracking system was evaluated. A robot was used to control the focused ultrasound and position it at the target that has been segmented from a real-time ultrasound video. Tracking accuracy and precision were investigated using a lesion mimicking phantom. Experiments have been conducted and results show sufficient efficiency of the image guidance algorithm. This work could be developed as the foundation for combining the real time ultrasound imaging tracking and MRI thermometry monitoring non-invasive surgery.

  1. Geometrothermodynamics of phantom AdS black holes

    Energy Technology Data Exchange (ETDEWEB)

    Quevedo, Hernando [Universidad Nacional Autonoma de Mexico, Instituto de Ciencias Nucleares, Mexico (Mexico); Universita di Roma ' ' La Sapienza' ' , Dipartimento di Fisica ed ICRANet, Rome (Italy); Quevedo, Maria N. [Facultad de Ciencias Basicas, Universidad Militar Nueva Granada, Departamento de Matematicas, Bogota (Colombia); Sanchez, Alberto [CIIDET, Departamento de Posgrado, Queretaro (Mexico)

    2016-03-15

    We show that to investigate the thermodynamic properties of charged phantom spherically symmetric anti-de Sitter black holes, it is necessary to consider the cosmological constant as a thermodynamic variable so that the corresponding fundamental equation is a homogeneous function defined on an extended equilibrium space. We explore all the thermodynamic properties of this class of black holes by using the classical physical approach, based upon the analysis of the fundamental equation, and the alternative mathematical approach as proposed in geometrothermodynamics. We show that both approaches are compatible and lead to equivalent results. (orig.)

  2. Phantom limb pain after lower limb trauma: origins and treatments.

    Science.gov (United States)

    Foell, Jens; Bekrater-Bodmann, Robin; Flor, Herta; Cole, Jonathan

    2011-12-01

    Phantom sensations, that is, sensations perceived in a body part that has been lost, are a common consequence of accidental or clinical extremity amputations. Most amputation patients report a continuing presence of the limb, with some describing additional sensations such as numbness, tickling, or cramping of the phantom limb. The type, frequency, and stability of these phantom sensations can vary immensely. The phenomenon of painful phantom sensations, that is, phantom limb pain, presents a challenge for practitioners and researchers and is often detrimental to the patient's quality of life. In addition to the use of conventional therapies for chronic pain disorders, recent years have seen the development of novel treatments for phantom limb pain, based on an increasing body of research on neurophysiological changes after amputation. This article describes the current state of research in regard to the demographics, causal factors, and treatments of phantom limb pain.

  3. A novel breast software phantom for biomechanical modeling of elastography.

    Science.gov (United States)

    Bhatti, Syeda Naema; Sridhar-Keralapura, Mallika

    2012-04-01

    In developing breast imaging technologies, testing is done with phantoms. Physical phantoms are normally used but their size, shape, composition, and detail cannot be modified readily. These difficulties can be avoided by creating a software breast phantom. Researchers have created software breast phantoms using geometric and/or mathematical methods for applications like image fusion. The authors report a 3D software breast phantom that was built using a mechanical design tool, to investigate the biomechanics of elastography using finite element modeling (FEM). The authors propose this phantom as an intermediate assessment tool for elastography simulation; for use after testing with commonly used phantoms and before clinical testing. The authors design the phantom to be flexible in both, the breast geometry and biomechanical parameters, to make it a useful tool for elastography simulation. The authors develop the 3D software phantom using a mechanical design tool based on illustrations of normal breast anatomy. The software phantom does not use geometric primitives or imaging data. The authors discuss how to create this phantom and how to modify it. The authors demonstrate a typical elastography experiment of applying a static stress to the top surface of the breast just above a simulated tumor and calculate normal strains in 3D and in 2D with plane strain approximations with linear solvers. In particular, they investigate contrast transfer efficiency (CTE) by designing a parametric study based on location, shape, and stiffness of simulated tumors. The authors also compare their findings to a commonly used elastography phantom. The 3D breast software phantom is flexible in shape, size, and location of tumors, glandular to fatty content, and the ductal structure. Residual modulus, maps, and profiles, served as a guide to optimize meshing of this geometrically nonlinear phantom for biomechanical modeling of elastography. At best, low residues (around 1-5 KPa) were

  4. Southeast Asian Refugee Parent Survey.

    Science.gov (United States)

    Blakely, Mary M.

    This paper summarizes the findings of a descriptive research project conducted among Southeast Asian parents in an Oregon school district, and discusses the issue of fieldwork methodology among refugee populations. The district studied had a student population of 18,000 (kindergarten through grade 12), with Southeast Asian refugees accounting for…

  5. Additional Resources on Asian Americans.

    Science.gov (United States)

    Kodama, Corinne Maekawa; Lee, Sunny; Liang, Christopher T. H.; Alvarez, Alvin N.; McEwen, Marylu K.

    2002-01-01

    The authors identify Asian American associations and organizations, academic journals, periodicals, and media resources. Selected annotated resources on Asian American activism and politics, counseling and psychology, educational issues, gender and sexual orientation, history, policy reports, and racial and ethnic identity are also included.…

  6. The Asian Newspaper's Reluctant Revolution.

    Science.gov (United States)

    Lent, John A., Ed.

    This book is composed of 19 articles written by both Asian and American scholars on the history and present conditions of newspapers in 15 Asian nations: China, Hong Kong, Japan, Korea, Taiwan, Australia, Burma, Indonesia, Malaysia and Singapore, the Philippines, Thailand, South Vietnam, Ceylon, India, and Pakistan. Two overviews of the Asian…

  7. Anechoic Sphere Phantoms for Estimating 3-D Resolution of Very High Frequency Ultrasound Scanners

    Science.gov (United States)

    Madsen, Ernest L.; Frank, Gary R.; McCormick, Matthew M.; Deaner, Meagan E.; Stiles, Timothy A.

    2013-01-01

    Two phantoms have been constructed for assessing the performance of high frequency ultrasound imagers. They also allow for periodic quality assurance tests. The phantoms contain eight blocks of tissue-mimicking material where each block contains a spatially random distribution of suitably small anechoic spheres having a small distribution of diameters. The eight mean sphere diameters are distributed from 0.10 to 1.09 mm. The two phantoms differ primarily in terms of the backscatter coefficient of the background material in which the spheres are suspended. The mean scatterer diameter for one phantom is larger than that for the other phantom resulting in a lesser increase in backscatter coefficient for the second phantom; however, the backscatter curves cross at about 35 MHz. Since spheres have no preferred orientation, all three (spatial) dimensions of resolution contribute to sphere detection on an equal basis; thus, the resolution is termed 3-D. Two high frequency scanners are compared. One employs single-element (fixed focus) transducers, and the other employs variable focus linear arrays. The nominal frequency for the single element transducers were 25 and 55 MHz and for the linear array transducers were 20, 30 and 40 MHz. The depth range for detection of spheres of each size is determined corresponding to determination of 3-D resolution as a function of depth. As expected, the single-element transducers are severely limited in useful imaging depth ranges compared with the linear arrays. Note that these phantoms could also be useful for training technicians in using higher frequency scanners. PMID:20889416

  8. A consistent formalism for the application of phantom and collimator scatter factors.

    Science.gov (United States)

    Venselaar, J L; van Gasteren, J J; Heukelom, S; Jager, H N; Mijnheer, B J; van der Laarse, R; Kleffens, H J; Westermann, C F

    1999-02-01

    A coherent system for the use of scatter correction factors, determined at 10 cm depth, is described for dose calculations on the central axis of arbitrarily shaped photon beams. The system is suitable for application in both the fixed source-surface distance (SSD) and in the isocentric treatment set-up. This is in contrast to some other proposals where only one of these approaches forms the basis of the calculation system or where distinct quantities and data sets are needed. In order to derive the relations in the formalism, we introduced a separation of the phenomena related to the energy fluence in air and to the phantom scatter contribution to the dose. Both are used relative to quantities defined for the reference irradiation set-up. It is shown that dose calculations can be performed with only one set of basic beam data, obtained at a reference depth of 10 cm. These data consist for each photon beam quality of measured collimator and phantom scatter correction factors, in combination with a set of (percentage/relative) depth-dose or tissue-phantom ratio values measured along the central axis of the beam. Problems related to measurements performed at the depth of maximum absorbed dose, due to the electron contamination of the beam, are avoided in this way. Collimator scatter correction factors are obtained by using a mini-phantom, while phantom scatter correction factors are derived from measurements in a full scatter phantom in combination with the results of the mini-phantom measurements. For practical reasons the fixed SSD system was chosen to determine the data. Then, dose calculations in a fixed SSD treatment set-up itself are straightforward. Application in the isocentric treatment set-up needs simple conversion steps, while the inverse approach, from isocentric to fixed SSD, is described as well. Differences between the two approaches are discussed and the equations for the conversions are given.

  9. Optical phantoms with adjustable subdiffusive scattering parameters

    Science.gov (United States)

    Krauter, Philipp; Nothelfer, Steffen; Bodenschatz, Nico; Simon, Emanuel; Stocker, Sabrina; Foschum, Florian; Kienle, Alwin

    2015-10-01

    A new epoxy-resin-based optical phantom system with adjustable subdiffusive scattering parameters is presented along with measurements of the intrinsic absorption, scattering, fluorescence, and refractive index of the matrix material. Both an aluminium oxide powder and a titanium dioxide dispersion were used as scattering agents and we present measurements of their scattering and reduced scattering coefficients. A method is theoretically described for a mixture of both scattering agents to obtain continuously adjustable anisotropy values g between 0.65 and 0.9 and values of the phase function parameter γ in the range of 1.4 to 2.2. Furthermore, we show absorption spectra for a set of pigments that can be added to achieve particular absorption characteristics. By additional analysis of the aging, a fully characterized phantom system is obtained with the novelty of g and γ parameter adjustment.

  10. Maladaptive plasticity: imprinting of past experiences onto phantom limb schemata.

    Science.gov (United States)

    Giummarra, Melita Joy; Georgiou-Karistianis, Nellie; Nicholls, Michael E R; Gibson, Stephen J; Chou, Michael; Bradshaw, John L

    2011-10-01

    Phantom limb perception is common following amputation, and is sometimes characterised by pain that resembles the characteristics, intensity or location of past pain. We tested Flor's model that phantom pain results from memory for long-lasting znoxious input. We report a questionnaire study of 283 amputees, that explored the experience of painful, non-painful and postural somatosensory memories in the phantom. We explore the impact of pre-amputation pain and impairment duration, and complications in the limb (eg, infection, gangrene, surgery, and vascular disease). Differences in mood, coping and adjustment to amputation are also explored in those with somatosensory pain memories. Our findings support Flor's model, as amputation-related and non-amputation-related pain memories, and non-painful memories comprised pains or sensations that were either enduring/recurring pains or sensations (eg, ingrown toenail, corns, chilblains, arthritis-type pain in winter, night-cramps, or holding a tennis racquet), or resulted from a painful event with a "core-trauma" element (eg, fracture, crushing/penetration injury). Pain memories related to amputation were more common following functional impairment before amputation; infection or surgery prior to amputation; or having diabetic or vascular amputations-which are associated with multiple complications, including neuropathic changes, infection and prior surgery. Furthermore, participants with amputation-related pain memories exhibited higher sensory pain ratings, as well as poorer mood and adjustment to the limitations of amputation. We propose that somatosensory pain memories likely relate to the generation and maintenance of limb representations upon which intense or emotionally powerful past experiences have been imprinted.

  11. Suggestions for an East Asian Monetary Union: Focusing on the Effects of Monetary Integration on Bilateral Trade

    Directory of Open Access Journals (Sweden)

    Min-Chang Ko

    2006-06-01

    Full Text Available This study explores alternative ways toward the East Asian monetary union, focusing on the effect of monetary integration on bilateral trade. For this purpose, we analyze with gravity model changes of the bilateral trade among countries of EU, NAFTA, and East Asia. A distinctive feature of this model is that it includes the dummy variables that show the cultural intimacy among North-East Asian countries, Asian NIEs countries, and East Asian countries (North-East Asian and ASEAN countries. We discovered that bilateral trade increased at a highest level among East Asian countries than the other two cases. This result suggests that the once-and-for-all strategy to develop an East Asian monetary union including North-East Asian and ASEAN countries would be more efficient than the multitrack strategy that forms the monetary union of North-East Asian countries in the first place and then tries to extend it to ASEAN countries.

  12. Phantom Space-times in Fake Supergravity

    OpenAIRE

    Taam, Maryam Bu; Sabra, Wafic A.

    2015-01-01

    We discuss phantom metrics admitting Killing spinors in fake N=2 , D=4 supergravity coupled to vector multiplets. The Abelian U(1) gauge fields in the fake theory have kinetic terms with the wrong sign. We solve the Killing spinor equations for the standard and fake theories in a unified fashion by introducing a parameter which distinguishes between the two theories. The solutions found are fully determined in terms of algebraic conditions, the so-called stabilisation equations, in which the ...

  13. Pre-evaluation study in SPECT images using a phantom; Avaliacao do pre processamento das projecoes em SPECT com phantom fisico

    Energy Technology Data Exchange (ETDEWEB)

    Rebelo, Marina de Sa; Furuie, Sergio Shiguemi [Sao Paulo Univ., SP (Brazil). Instituto do Coracao. Div. de Informatica; Abe, Rubens [Sao Paulo Univ., SP (Brazil). Instituto do Coracao. Servico de Radioisotopos; Moura, Lincoln [Sao Paulo Univ., SP (Brazil). Faculdade de Medicina. Hospital das Clinicas

    1996-12-31

    An alternative solution for the reconstruction of SPECT images using a Poisson Noise Model is presented. The proposed algorithm was applied on a real phantom and compared to the standard clinical procedures. Results have shown that the proposed method improves the quality of the SPECT images 3 refs.

  14. Automatic Synthesis of Anthropomorphic Pulmonary CT Phantoms

    Science.gov (United States)

    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

  15. Automatic Synthesis of Anthropomorphic Pulmonary CT Phantoms.

    Directory of Open Access Journals (Sweden)

    Daniel Jimenez-Carretero

    Full Text Available 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.

  16. NOTE: A dosimetric evaluation of water equivalent phantoms for kilovoltage x-ray beams

    Science.gov (United States)

    Hill, R.; Holloway, L.; Baldock, C.

    2005-11-01

    Solid phantoms are widely used in radiation therapy for both relative and reference dosimetry. Two water equivalent phantoms, RMI-457 Solid Water and Plastic Water, were evaluated for use in kilovoltage x-ray dosimetry in the energy range from 75 to 300 kVp. Relative and reference dosimetry measurements were performed in the solid phantoms and compared with water. The results indicate that RMI-457 Solid Water could be used for output factor determination for all energies tested and the measurement of percentage depth doses for the 300 kVp x-ray beam, with data agreeing to within 1%, compared to the same measurements in water. For the same criteria, Plastic Water could only be used for output factor determination of the 300 kVp x-ray beam. The superior agreement of the calculated mass energy absorption coefficients for Solid Water and water, as compared to Plastic Water and water was consistent with the experimental results. Reference dosimetry is not recommended with the solid phantoms for the energies studied due to the lack of published correction factors. It is recommended that any solid phantom be tested by comparison with water in the same manner before being used for the dosimetry of kilovoltage x-ray beams.

  17. Low-echo sphere phantoms and methods for assessing imaging performance of medical ultrasound scanners.

    Science.gov (United States)

    Madsen, Ernest L; Song, Chihwa; Frank, Gary R

    2014-07-01

    Tissue-mimicking phantoms and software for quantifying the ability of human observers to detect small low-echo spheres as a function of depth have been developed. Detectability is related to the imager's ability to delineate the boundary of a 3-D object such as a spiculated tumor. The phantoms accommodate a broad range of transducer shapes and sizes. Three phantoms are described: one with 2-mm-diameter spheres (for higher frequencies), one with 3.2-mm-diameter spheres (for lower frequencies) and one with 4-mm-diameter spheres (for lower frequencies). The spheres are randomly distributed in each phantom. The attenuation coefficients of spheres and surroundings are nearly identical; thus, compromising shadowing or enhancement distal to spheres does not occur. Reproducibility results are given for pairs of independent data sets involving eight different combinations of scanner, transducer and console settings. The following comparison results are also reported: (i) only the selected frequency differs; (ii) transducers and scan parameters are nearly the same but manufacturers differ; (iii) ordinary B-scanning, spatial compounding and tissue harmonic imaging are addressed. The phantoms and software promise to be valuable tools for scanning system and setup comparisons and for acceptance testing. Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  18. [Somatognosis, body schema and the phenomena of somatic and visceral phantoms and phantom pain].

    Science.gov (United States)

    Tichý, J

    2003-01-01

    The body scheme is a complex of memory patterns secured in the structures of the brain, where the parietal lobes play the most important role. Basic principles are given by the genetic programming of the structure and function along with the synthesis of information brought by means of sensory activity. The unitary perception of the body scheme is a dynamic image, enabling conscious and unconscious representation of our body, its parts, their functions, position, shape and/or movements. The recognition of the body scheme in humans is named somatognosia. Disorders of somatognosia include visceral and somatic phantom, phantom pain and other disorders related to the capability of communication by means of language: autotopoagnosia, hemiasomatognosia, pain asymboly, anosognosia of hemiplegia, anosognosia of blindness, deafness, neglect and other defects appearing at the neurologist's and psychiatrist's borderline of interest. Interest in the visceral phantom is usually much smaller than that in the phantom limb. The aim of this paper was to draw the to phantom phenomena in patients following rectum amputation and colostomy. A survey of contemporary knowledge about the body scheme and its disorders, cortical plasticity and the problem of cortical maladaptation are presented.

  19. Performance Evaluation of a Multichannel All-In-One Phantom Dosimeter for Dose Measurement of Diagnostic X-ray Beam

    Directory of Open Access Journals (Sweden)

    Hyesu Jeon

    2015-11-01

    Full Text Available We developed a multichannel all-in-one phantom dosimeter system composed of nine sensing probes, a chest phantom, an image intensifier, and a complementary metal-oxide semiconductor (CMOS image sensor to measure the dose distribution of an X-ray beam used in radiation diagnosis. Nine sensing probes of the phantom dosimeter were fabricated identically by connecting a plastic scintillating fiber (PSF to a plastic optical fiber (POF. To measure the planar dose distribution on a chest phantom according to exposure parameters used in clinical practice, we divided the top of the chest phantom into nine equal parts virtually and then installed the nine sensing probes at each center of the nine equal parts on the top of the chest phantom as measuring points. Each scintillation signal generated in the nine sensing probes was transmitted through the POFs and then intensified by the image intensifier because the scintillation signal normally has a very low light intensity. Real-time scintillation images (RSIs containing the intensified scintillation signals were taken by the CMOS image sensor with a single lens optical system and displayed through a software program. Under variation of the exposure parameters, we measured RSIs containing dose information using the multichannel all-in-one phantom dosimeter and compared the results with the absorbed doses obtained by using a semiconductor dosimeter (SCD. From the experimental results of this study, the light intensities of nine regions of interest (ROI in the RSI measured by the phantom dosimeter were similar to the dose distribution obtained using the SCD. In conclusion, we demonstrated that the planar dose distribution including the entrance surface dose (ESD can be easily measured by using the proposed phantom dosimeter system.

  20. Inclusion of skin target layer in mesh-type ICRP reference phantoms and calculations of skin dose coefficients

    Energy Technology Data Exchange (ETDEWEB)

    Yeom, Yeon Soo; Nguyen, Thang Tat; Kim, Han Sung; Choi, Chan Soo; Han, Min Cheol; Kim, Chan Hyeong [Dept. of Nuclear Engineering, Hanyang University, Seoul (Korea, Republic of)

    2016-04-15

    The current ICRP-110 reference phantoms cannot represent the 50-μm-thick sensitive target layer within the skin due to their limited voxel resolutions. Thus, skin doses have been approximated by averaging absorbed dose over the entire skin of the ICRP-110 phantoms and were used to produce the skin dose coefficients (SDC) for whole body external exposures given in ICRP Publication 116. In order to address the limitation, the present study included the 50-μm-thick skin target layer in the mesh-type ICRP reference phantoms which have been converted from the ICRP-110 phantoms in a research project under ICRP Committee 2. The mesh phantoms including the target layer were then used to calculate SDCs for whole body external exposures and the calculated values were compared with the values in the ICRP-116 values. In order to address the limitation of the ICRP-110 phantoms, the present study included the 50-μm-thick target layer in the skin of the mesh-type ICRP reference phantoms under development and calculated SDCs considering the target layer for whole body external exposures. The results of the study showed significant dose differences for electron exposures when compared with the ICRP-116 data.

  1. Electrical Impedance Spectroscopic Studies on Broiler Chicken Tissue Suitable for the Development of Practical Phantoms in Multifrequency EIT

    Directory of Open Access Journals (Sweden)

    Tushar Kanti Bera

    2011-06-01

    Full Text Available Phantoms are essential for assessing the system performance in Electrical Impedance Tomography (EIT. Saline phantoms with insulator inhomogeneity fail to mimic the physiological structure of real body tissue in several aspects. Saline or any other salt solutions are purely resistive and hence studying multifrequency EIT systems cannot be assessed with saline phantoms because the response of the purely resistive materials do not change over frequency. Animal tissues show a variable response over a wide band of signal frequency due to their complex physiological and physiochemical structures and hence they can suitably be used as bathing medium and inhomogeneity in the phantoms of multifrequency EIT system. An efficient assessment of a multifrequency EIT system with real tissue phantom needs a prior knowledge of the impedance profile of the bathing medium as well as the inhomogeneity. In this direction Electrical Impedance Spectroscopy (EIS of broiler chicken muscle tissue paste and broiler chicken fat tissue is conducted from 10 Hz to 2 MHz using an impedance analyzer and their impedance profiles are thoroughly studied. Results show that the broiler chicken muscle tissue paste is less resistive than the fat tissue and hence it can be successfully used as the bathing medium of the phantoms for resistivity imaging in multifrequency EIT. Fat tissue is found more resistive than the muscle tissue which makes it more suitable for the inhomogeneity in phantoms of resistivity imaging study. doi:10.5617/jeb.174 J Electr Bioimp, vol. 2, pp. 48-63, 2011

  2. Realistic phantoms to characterize dosimetry in pediatric CT

    Energy Technology Data Exchange (ETDEWEB)

    Carver, Diana E.; Kost, Susan D.; Fraser, Nicholas D.; Pickens, David R.; Price, Ronald R.; Stabin, Michael G. [Vanderbilt University Medical Center, Department of Radiology and Radiological Sciences, Nashville, TN (United States); Segars, W.P. [Duke University, Carl E. Ravin Advanced Imaging Laboratories, Durham, NC (United States)

    2017-05-15

    The estimation of organ doses and effective doses for children receiving CT examinations is of high interest. Newer, more realistic anthropomorphic body models can provide information on individual organ doses and improved estimates of effective dose. Previously developed body models representing 50th-percentile individuals at reference ages (newborn, 1, 5, 10 and 15 years) were modified to represent 10th, 25th, 75th and 90th height percentiles for both genders and an expanded range of ages (3, 8 and 13 years). We calculated doses for 80 pediatric reference phantoms from simulated chest-abdomen-pelvis exams on a model of a Philips Brilliance 64 CT scanner. Individual organ and effective doses were normalized to dose-length product (DLP) and fit as a function of body diameter. We calculated organ and effective doses for 80 reference phantoms and plotted them against body diameter. The data were well fit with an exponential function. We found DLP-normalized organ dose to correlate strongly with body diameter (R{sup 2}>0.95 for most organs). Similarly, we found a very strong correlation with body diameter for DLP-normalized effective dose (R{sup 2}>0.99). Our results were compared to other studies and we found average agreement of approximately 10%. We provide organ and effective doses for a total of 80 reference phantoms representing normal-stature children ranging in age and body size. This information will be valuable in replacing the types of vendor-reported doses available. These data will also permit the recording and tracking of individual patient doses. Moreover, this comprehensive dose database will facilitate patient matching and the ability to predict patient-individualized dose prior to examination. (orig.)

  3. iPads in Breast Imaging - A Phantom Study.

    Science.gov (United States)

    Hammon, M; Schlechtweg, P M; Schulz-Wendtland, R; Uder, M; Schwab, S A

    2014-02-01

    Introduction: Modern tablet PCs as the iPad are becoming more and more integrated into medicine. The aim of this study was to evaluate the display quality of iPads regarding digital mammography. Materials and Methods: Three experienced readers compared the display quality of the iPad 2 and 3 with a dedicated 10 megapixel (MP) mammography liquid crystal display (LCD) screen in consensus using the standardized Contrast Detail Mammography (CDMAM) phantom. Phantom fields without agreement between the readers were classified as "uncertain", correct 2 : 1 decisions were classified as "uncertain/readable". In a second step display quality of the three reading devices was judged subjectively in a side by side comparison. Results: The 10 MP screen was superior to both iPads in 4 (phantom-)fields and inferior in 2 fields. Comparing the iPads, version 3 was superior in 4 fields and version 2 was superior in 1 field. However these differences were not significant. Total number of "uncertain" fields did not show significant differences. The number of "uncertain" fields was 15 with the 10 MP screen, 16 with the iPad 2 and 17 with the iPad 3 (p > 0.05), the number of "uncertain/readable" fields was 4, 7 and 8, respectively. Subjective image quality of the iPad 3 and the 10 MP screen was rated superior to the iPad 2. Conclusion: The evaluated iPads, especially in version 3, seem to be adequate to display mammograms in a diagnostic quality and thus could be useful e.g. for patient consultation, clinical demonstration or educational and teaching purposes. However primary mammogram reading should still be performed on dedicated large sized reading screens.

  4. iPads in Breast Imaging – A Phantom Study

    Science.gov (United States)

    Hammon, M.; Schlechtweg, P. M.; Schulz-Wendtland, R.; Uder, M.; Schwab, S. A.

    2014-01-01

    Introduction: Modern tablet PCs as the iPad are becoming more and more integrated into medicine. The aim of this study was to evaluate the display quality of iPads regarding digital mammography. Materials and Methods: Three experienced readers compared the display quality of the iPad 2 and 3 with a dedicated 10 megapixel (MP) mammography liquid crystal display (LCD) screen in consensus using the standardized Contrast Detail Mammography (CDMAM) phantom. Phantom fields without agreement between the readers were classified as “uncertain”, correct 2 : 1 decisions were classified as “uncertain/readable”. In a second step display quality of the three reading devices was judged subjectively in a side by side comparison. Results: The 10 MP screen was superior to both iPads in 4 (phantom-)fields and inferior in 2 fields. Comparing the iPads, version 3 was superior in 4 fields and version 2 was superior in 1 field. However these differences were not significant. Total number of “uncertain” fields did not show significant differences. The number of “uncertain” fields was 15 with the 10 MP screen, 16 with the iPad 2 and 17 with the iPad 3 (p > 0.05), the number of “uncertain/readable” fields was 4, 7 and 8, respectively. Subjective image quality of the iPad 3 and the 10 MP screen was rated superior to the iPad 2. Conclusion: The evaluated iPads, especially in version 3, seem to be adequate to display mammograms in a diagnostic quality and thus could be useful e.g. for patient consultation, clinical demonstration or educational and teaching purposes. However primary mammogram reading should still be performed on dedicated large sized reading screens. PMID:24741126

  5. [Are clinical features derived from evidences and experiences outside of Japan applicable to clinical practices in Japan? Comparisons of results among studies conducted in US, Europe, Asian Countries and Japan].

    Science.gov (United States)

    Kamada, Kyousuke

    2011-03-01

    Levetiracetam is an antiepileptic drug (AED) approved for the adjunctive treatment of partial seizures firstly in the US in 1999. In Japan, levetiracetam was approved for the adjunctive treatment of partial seizures. Accumulated evidences and experiences in US, Europe and Asian counties have indicated clinical features of levetiracetam (i.e., rapid onset of action, high efficacy and tolerability, no drug-drug interactions). One may ask whether the known clinical features are applicable to Japanese epilepsy patients with partial seizures. This article is aimed at answering such questions by reviewing published articles on effects of races onto pharmacokinetics and on efficacy and safety profiles shown in studies conducted in the US, Europe, Taiwan, China, Korea, Asian 6 countries and Japan, which allowed to compare the profiles across the different populations. Pharmacokinetic profiles were not different between Western and Japanese, and between Chinese and Western populations. The values of efficacy variables such as percentage (%) reduction of seizure frequency from baselines, 50% responder rate and seizure free rate at dose range of 1,000 mg-3,000 mg/d were similar across 4 open studies (Korea, 6 Asian countries, US, Europe and other western; % reduction: 43.2-52.3%, 50% responder rate: 43.6-57.9%, Seizure free rate: 16.2-20.2%). In the 6 placebo-controlled double blind studies (US, 2 Europe studies, China, Taiwan and Japan), the values of the efficacy variables of the levetiracetam arms (1,000 mg/d, 2,000 mg/d, 3,000 mg/d, 1,000-2,000 mg/d, 2,000-3,000 mg/d) were at least numerically superior to those of corresponding placebo arms even though the statistical significance was not obtained for all of the variables. The degrees of difference between the values of placebo and levetiracetam arms were within comparable ranges. These comparisons suggested levetiracetam would have similar efficacy and safety profiles in Japanese patients to those in the US, Europe, and

  6. Internalized model minority myth, Asian values, and help-seeking attitudes among Asian American students.

    Science.gov (United States)

    Kim, Paul Youngbin; Lee, Donghun

    2014-01-01

    The present study examined cultural factors underlying help-seeking attitudes of Asian American college students (N = 106). Specifically, we explored internalized model minority myth as a predictor of help-seeking attitudes and tested an intrapersonal-interpersonal framework of Asian values as a mechanism by which the two are related. Results indicated that internalized model minority myth significantly predicted unfavorable help-seeking attitudes, and emotional self-control mediated this relationship. Interpersonal values and humility were nonsignificant mediators, contrary to our hypotheses. The findings suggest that the investigation of internalized model minority myth in help-seeking research is a worthwhile endeavor, and they also highlight emotional self-control as an important explanatory variable in help-seeking attitudes of Asian American college students.

  7. Comparison study of reconstruction algorithms for prototype digital breast tomosynthesis using various breast phantoms.

    Science.gov (United States)

    Kim, Ye-seul; Park, Hye-suk; Lee, Haeng-Hwa; Choi, Young-Wook; Choi, Jae-Gu; Kim, Hak Hee; Kim, Hee-Joung

    2016-02-01

    Digital breast tomosynthesis (DBT) is a recently developed system for three-dimensional imaging that offers the potential to reduce the false positives of mammography by preventing tissue overlap. Many qualitative evaluations of digital breast tomosynthesis were previously performed by using a phantom with an unrealistic model and with heterogeneous background and noise, which is not representative of real breasts. The purpose of the present work was to compare reconstruction algorithms for DBT by using various breast phantoms; validation was also performed by using patient images. DBT was performed by using a prototype unit that was optimized for very low exposures and rapid readout. Three algorithms were compared: a back-projection (BP) algorithm, a filtered BP (FBP) algorithm, and an iterative expectation maximization (EM) algorithm. To compare the algorithms, three types of breast phantoms (homogeneous background phantom, heterogeneous background phantom, and anthropomorphic breast phantom) were evaluated, and clinical images were also reconstructed by using the different reconstruction algorithms. The in-plane image quality was evaluated based on the line profile and the contrast-to-noise ratio (CNR), and out-of-plane artifacts were evaluated by means of the artifact spread function (ASF). Parenchymal texture features of contrast and homogeneity were computed based on reconstructed images of an anthropomorphic breast phantom. The clinical images were studied to validate the effect of reconstruction algorithms. The results showed that the CNRs of masses reconstructed by using the EM algorithm were slightly higher than those obtained by using the BP algorithm, whereas the FBP algorithm yielded much lower CNR due to its high fluctuations of background noise. The FBP algorithm provides the best conspicuity for larger calcifications by enhancing their contrast and sharpness more than the other algorithms; however, in the case of small-size and low

  8. The Asian Taenia and the possibility of cysticercosis

    Science.gov (United States)

    V. Fuentes, Màrius

    2000-01-01

    In certain Asian countries, a third form of human Taenia, also known as the Asian Taenia, has been discovered. This Asian Taenia seems to be an intermediate between Taenia solium and T. saginata since in morphological terms it is similar to T. saginata, yet biologically, as it uses the same intermediate host (pigs), it is more akin to T. solium. Taenia solium causes human cysticercosis, while T. saginata does not. It is not known whether the Asian taeniid is able to develop to the larval stage in humans or not. The arguments proposed by those authors who consider it unlikely that the Asian Taenia causes human cysticercosis are: (a) its molecular similarities with T. saginata; (b) the absence of cases of human cysticercosis in populations where the Asian adult is highly prevalent; and (c) the unsupporting results derived from an experimental infestation study. These three arguments are debated, although bearing in mind that at present there is still no clear scientific data to support that human cysticercosis can be caused by the Asian Taenia. PMID:10743352

  9. The Confucian Asian cluster

    Directory of Open Access Journals (Sweden)

    Ionel Sergiu Pirju

    2013-11-01

    Full Text Available The Confucian Asian cluster consists of China, Hong Kong, Japan, Singapore, South Korea, and Taiwan. Confucian tradition countries were defined by achieving a consistent performance in the global economy, they still representing the major competitors in the EU and North American countries. Their progress is defined by a great national management that was able to influence beneficial management systems applied in organizations, these rules characterized by authority; aims to ensure the confidence in business. This article will present the intercultural values characterizing it, the leadership style and also tracing major macroeconomic considerations. The research is synchronic, analysing the contemporary situation of these countries, and the analysis will be interdisciplinary exploratory, identifying specific regional cultural elements.

  10. Fighting Asian soybean rust

    Directory of Open Access Journals (Sweden)

    Caspar eLangenbach

    2016-06-01

    Full Text Available Phakopsora pachyrhizi is a biotrophic fungus provoking Asian soybean rust (SBR disease. SBR poses a major threat to global soybean production. Though several resistance genes provided soybean immunity to certain P. pachyrhizi races, the pathogen swiftly overcame this resistance. Therefore, fungicides are the only current means to control SBR. However, insensitivity to fungicides is soaring in P. pachyrhizi and, therefore, alternative measures are needed for SBR control. In this article, we discuss the different approaches for fighting SBR and their potential, disadvantages, and advantages over other measures. These encompass conventional breeding for SBR resistance, transgenic approaches, exploitation of transcription factors, secondary metabolites, and antimicrobial peptides, RNAi/HIGS, and biocontrol strategies. It seems that an integrating approach exploiting different measures is likely to provide the best possible means for the effective control of SBR.

  11. Design and construction of a brain phantom to simulate neonatal MR images.

    Science.gov (United States)

    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. Copyright © 2010 Elsevier Ltd. All rights reserved.

  12. Preliminary Evidence for Training-Induced Changes of Morphology and Phantom Limb Pain.

    Science.gov (United States)

    Preißler, Sandra; Thielemann, Désirée; Dietrich, Caroline; Hofmann, Gunther O; Miltner, Wolfgang H R; Weiss, Thomas

    2017-01-01

    The aim of this study was to investigate whether a special prosthetic training in phantom limb pain patients aimed at increasing the functional use of the prosthesis leads to neural morphological plasticity of brain structures and a reduction in phantom limb pain. For chronic pain disorders, it was shown that morphological alterations due to pain might become at least partially reversed by pain therapies. Phantom limb pain is a chronic pain disorder that is frequently followed by neural plasticity of anatomical brain structures. In our study, 10 patients with amputation of the upper limb participated in a two-week training with a myoelectric prosthesis with somatosensory feedback. Grip strength was fed back with electrocutaneous stimulus patterns applied to the stump. Phantom limb pain was assessed before and after the two-week training. Similarly, two T1 weighted MRI scans were conducted for longitudinal thickness analyses of cortical brain structures. As result of this treatment, patients experienced a reduction in phantom limb pain and a gain in prosthesis functionality. Furthermore, we found a change of cortical thickness in small brain areas in the visual stream and the post-central gyrus ipsilateral to the amputation indicating morphological alterations in brain areas involved in vision and pain processing.

  13. Abnormal functioning of the thalamocortical system underlies the conscious awareness of the phantom limb phenomenon.

    Science.gov (United States)

    Romero-Romo, J I; Bauer, C C C; Pasaye, E H; Gutiérrez, R A; Favila, R; Barrios, F A

    2010-12-01

    Phantom limb (PL), a phenomenon experienced by most patients after amputation, has mostly served as a paradigm to study experiences that appear to be associated with neural plasticity within the CNS. However, the subjective nature of PL experiences has had no definitive means of reliable assessment other than using patients' direct reports, nor was there a way to study the neural mechanisms involved in the conscious awareness of this mental phenomenon. Here we obtained patients' indirect responses to PL experiences for an objective evaluation using functional magnetic resonance imaging (fMRI). Six control subjects and six lower limb (LL) amputees participated in a motor imagery task for both the intact and the particular phantom toes. While all subjects shared neural processing of distinctive regional cerebral activations during motor imagery of the intact toes (prefrontal (PF), supplementary motor area (SMA), primary motor cortex (M1), superior temporal gyrus (STG)), it was only during motor imagery of the amputated toes in amputees that we observed an increased blood oxygen level-dependent (BOLD) signal in the contralateral basal ganglia at the medial globus pallidus (MGP), substantia nigra (SN), and thalamus. This increased BOLD signal in the basal ganglia-thalamus-cortex pathway during imaginary movement of the phantom toes may reflect an abnormal open loop functioning of the thalamocortical system underlying the conscious awareness of the phantom phenomenon. We suggest that the reduction in afferent information contributes to and coalesces with the higher-level reorganization resulting in the subjective conscious awareness of the phantom limb.

  14. Analysis of translational errors in frame-based and frameless cranial radiosurgery using an anthropomorphic phantom

    Directory of Open Access Journals (Sweden)

    Taynná Vernalha Rocha Almeida

    2016-04-01

    Full Text Available Abstract Objective: To evaluate three-dimensional translational setup errors and residual errors in image-guided radiosurgery, comparing frameless and frame-based techniques, using an anthropomorphic phantom. Materials and Methods: We initially used specific phantoms for the calibration and quality control of the image-guided system. For the hidden target test, we used an Alderson Radiation Therapy (ART-210 anthropomorphic head phantom, into which we inserted four 5mm metal balls to simulate target treatment volumes. Computed tomography images were the taken with the head phantom properly positioned for frameless and frame-based radiosurgery. Results: For the frameless technique, the mean error magnitude was 0.22 ± 0.04 mm for setup errors and 0.14 ± 0.02 mm for residual errors, the combined uncertainty being 0.28 mm and 0.16 mm, respectively. For the frame-based technique, the mean error magnitude was 0.73 ± 0.14 mm for setup errors and 0.31 ± 0.04 mm for residual errors, the combined uncertainty being 1.15 mm and 0.63 mm, respectively. Conclusion: The mean values, standard deviations, and combined uncertainties showed no evidence of a significant differences between the two techniques when the head phantom ART-210 was used.

  15. Analysis of translational errors in frame-based and frameless cranial radiosurgery using an anthropomorphic phantom

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Taynna Vernalha Rocha [Faculdades Pequeno Principe (FPP), Curitiba, PR (Brazil); Cordova Junior, Arno Lotar; Almeida, Cristiane Maria; Piedade, Pedro Argolo; Silva, Cintia Mara da, E-mail: taynnavra@gmail.com [Centro de Radioterapia Sao Sebastiao, Florianopolis, SC (Brazil); Brincas, Gabriela R. Baseggio [Centro de Diagnostico Medico Imagem, Florianopolis, SC (Brazil); Marins, Priscila; Soboll, Danyel Scheidegger [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil)

    2016-03-15

    Objective: To evaluate three-dimensional translational setup errors and residual errors in image-guided radiosurgery, comparing frameless and frame-based techniques, using an anthropomorphic phantom. Materials and Methods: We initially used specific phantoms for the calibration and quality control of the image-guided system. For the hidden target test, we used an Alderson Radiation Therapy (ART)-210 anthropomorphic head phantom, into which we inserted four 5- mm metal balls to simulate target treatment volumes. Computed tomography images were the taken with the head phantom properly positioned for frameless and frame-based radiosurgery. Results: For the frameless technique, the mean error magnitude was 0.22 ± 0.04 mm for setup errors and 0.14 ± 0.02 mm for residual errors, the combined uncertainty being 0.28 mm and 0.16 mm, respectively. For the frame-based technique, the mean error magnitude was 0.73 ± 0.14 mm for setup errors and 0.31 ± 0.04 mm for residual errors, the combined uncertainty being 1.15 mm and 0.63 mm, respectively. Conclusion: The mean values, standard deviations, and combined uncertainties showed no evidence of a significant differences between the two techniques when the head phantom ART-210 was used. (author)

  16. Preliminary Evidence for Training-Induced Changes of Morphology and Phantom Limb Pain

    Science.gov (United States)

    Preißler, Sandra; Thielemann, Désirée; Dietrich, Caroline; Hofmann, Gunther O.; Miltner, Wolfgang H. R.; Weiss, Thomas

    2017-01-01

    The aim of this study was to investigate whether a special prosthetic training in phantom limb pain patients aimed at increasing the functional use of the prosthesis leads to neural morphological plasticity of brain structures and a reduction in phantom limb pain. For chronic pain disorders, it was shown that morphological alterations due to pain might become at least partially reversed by pain therapies. Phantom limb pain is a chronic pain disorder that is frequently followed by neural plasticity of anatomical brain structures. In our study, 10 patients with amputation of the upper limb participated in a two-week training with a myoelectric prosthesis with somatosensory feedback. Grip strength was fed back with electrocutaneous stimulus patterns applied to the stump. Phantom limb pain was assessed before and after the two-week training. Similarly, two T1 weighted MRI scans were conducted for longitudinal thickness analyses of cortical brain structures. As result of this treatment, patients experienced a reduction in phantom limb pain and a gain in prosthesis functionality. Furthermore, we found a change of cortical thickness in small brain areas in the visual stream and the post-central gyrus ipsilateral to the amputation indicating morphological alterations in brain areas involved in vision and pain processing. PMID:28676749

  17. Preliminary Evidence for Training-Induced Changes of Morphology and Phantom Limb Pain

    Directory of Open Access Journals (Sweden)

    Sandra Preißler

    2017-06-01

    Full Text Available The aim of this study was to investigate whether a special prosthetic training in phantom limb pain patients aimed at increasing the functional use of the prosthesis leads to neural morphological plasticity of brain structures and a reduction in phantom limb pain. For chronic pain disorders, it was shown that morphological alterations due to pain might become at least partially reversed by pain therapies. Phantom limb pain is a chronic pain disorder that is frequently followed by neural plasticity of anatomical brain structures. In our study, 10 patients with amputation of the upper limb participated in a two-week training with a myoelectric prosthesis with somatosensory feedback. Grip strength was fed back with electrocutaneous stimulus patterns applied to the stump. Phantom limb pain was assessed before and after the two-week training. Similarly, two T1 weighted MRI scans were conducted for longitudinal thickness analyses of cortical brain structures. As result of this treatment, patients experienced a reduction in phantom limb pain and a gain in prosthesis functionality. Furthermore, we found a change of cortical thickness in small brain areas in the visual stream and the post-central gyrus ipsilateral to the amputation indicating morphological alterations in brain areas involved in vision and pain processing.

  18. Development of an Anthropomorphic Breast Phantom for Combined PET, B-Mode Ultrasound and Elastographic Imaging

    CERN Document Server

    Dang, J; Tavernier, S; Lasaygues, P; Mensah, S; Zhang, D C; Auffray, E; Frisch, B; Varela, J; Wan, M X; Felix, N

    2011-01-01

    Combining the advantages of different imaging modalities leads to improved clinical results. For example, ultrasound provides good real-time structural information without any radiation and PET provides sensitive functional information. For the ongoing ClearPEM-Sonic project combining ultrasound and PET for breast imaging, we developed a dual-modality PET/Ultrasound (US) phantom. The phantom reproduces the acoustic and elastic properties of human breast tissue and allows labeling the different tissues in the phantom with different concentrations of FDG. The phantom was imaged with a whole-body PET/CT and with the Supersonic Imagine Aixplorer system. This system allows both B-mode US and shear wave elastographic imaging. US elastography is a new imaging method for displaying the tissue elasticity distribution. It was shown to be useful in breast imaging. We also tested the phantom with static elastography. A 6D magnetic positioning system allows fusing the images obtained with the two modalities. ClearPEM-Soni...

  19. An analytical phantom for the evaluation of medical flow imaging algorithms

    Science.gov (United States)

    Pashaei, A.; Fatouraee, N.

    2009-03-01

    Blood flow characteristics (e.g. velocity, pressure, shear stress, streamline and volumetric flow rate) are effective tools in diagnosis of cardiovascular diseases such as atherosclerotic plaque, aneurism and cardiac muscle failure. Noninvasive estimation of cardiovascular blood flow characteristics is mostly limited to the measurement of velocity components by medical imaging modalities. Once the velocity field is obtained from the images, other flow characteristics within the cardiovascular system can be determined using algorithms relating them to the velocity components. In this work, we propose an analytical flow phantom to evaluate these algorithms accurately. The Navier-Stokes equations are used to derive this flow phantom. The exact solution of these equations obtains analytical expression for the flow characteristics inside the domain. Features such as pulsatility, incompressibility and viscosity of flow are included in a three-dimensional domain. The velocity domain of the resulted system is presented as reference images. These images could be employed to evaluate the performance of different flow characteristic algorithms. In this study, we also present some applications of the obtained phantom. The calculation of pressure domain from velocity data, volumetric flow rate, wall shear stress and particle trace are the characteristics whose algorithms are evaluated here. We also present the application of this phantom in the analysis of noisy and low-resolution images. The presented phantom can be considered as a benchmark test to compare the accuracy of different flow characteristic algorithms.

  20. Analysis of translational errors in frame-based and frameless cranial radiosurgery using an anthropomorphic phantom*

    Science.gov (United States)

    Almeida, Taynná Vernalha Rocha; Cordova Junior, Arno Lotar; Piedade, Pedro Argolo; da Silva, Cintia Mara; Marins, Priscila; Almeida, Cristiane Maria; Brincas, Gabriela R. Baseggio; Soboll, Danyel Scheidegger

    2016-01-01

    Objective To evaluate three-dimensional translational setup errors and residual errors in image-guided radiosurgery, comparing frameless and frame-based techniques, using an anthropomorphic phantom. Materials and Methods We initially used specific phantoms for the calibration and quality control of the image-guided system. For the hidden target test, we used an Alderson Radiation Therapy (ART)-210 anthropomorphic head phantom, into which we inserted four 5mm metal balls to simulate target treatment volumes. Computed tomography images were the taken with the head phantom properly positioned for frameless and frame-based radiosurgery. Results For the frameless technique, the mean error magnitude was 0.22 ± 0.04 mm for setup errors and 0.14 ± 0.02 mm for residual errors, the combined uncertainty being 0.28 mm and 0.16 mm, respectively. For the frame-based technique, the mean error magnitude was 0.73 ± 0.14 mm for setup errors and 0.31 ± 0.04 mm for residual errors, the combined uncertainty being 1.15 mm and 0.63 mm, respectively. Conclusion The mean values, standard deviations, and combined uncertainties showed no evidence of a significant differences between the two techniques when the head phantom ART-210 was used. PMID:27141132

  1. Dosimetric evaluation of Rhizophora spp. binderless particleboard phantom for diagnostic X-ray energy

    Science.gov (United States)

    Marashdeh, M. W.; Tajuddin, A. A.; Bauk, S.; Hashim, R.

    2017-07-01

    This research aims to evaluate the suitability of using binderless particleboard made from Rhizophora spp. mangrove wood as a dosimetric phantom for X-ray in the diagnostic energy regions. Comparative measurements of percentage depth and surface doses in Rhizophora spp. binderless particleboard phantom and similarly shaped Perspex and water phantoms were performed. Measurements were conducted in the diagnostic X-ray energy range of 50 kVp to 90 kVp. Results showed that the binderless particleboard phantom can be used for dosimetric measurements. For the X-ray beam at 90 kVp, the binderless particleboard and water phantom showed data agreement of 1.6%, 2.7%, and 4.3% at depths of 1, 2, and 4 cm, respectively, whereas the measurements in water and Perspex were 1.8%, 2.7%, and 4.4%. The surface dose differences were due to difference in the backscattering material. The doses measured at the surface were within 0.4% for binderless particleboard and water and within 0.9% for Perspex and water.

  2. Specific developed phantoms and software to assess radiological equipment image quality

    Energy Technology Data Exchange (ETDEWEB)

    Verdu, G., E-mail: gverdu@iqn.upv.es [Universidad Politecnica de Valencia (Spain). Dept. de Ingenieria Quimica y Nuclear; Mayo, P., E-mail: p.mayo@titaniast.com [TITANIA Servicios Teconologicos, Valencia (Spain); Rodenas, F., E-mail: frodenas@mat.upv.es [Universidad Politecnica de Valencia (Spain). Dept. de Matematica Aplicada; Campayo, J.M., E-mail: j.campayo@lainsa.com [Logistica y Acondicionamientos Industriales S.A.U (LAINSA), Valencia (Spain)

    2011-07-01

    The use of radiographic phantoms specifically designed to evaluate the operation of the radiographic equipment lets the study of the image quality obtained by this equipment in an objective way. In digital radiographic equipment, the analysis of the image quality can be automatized because the acquisition of the image is possible in different technologies that are, computerized radiography or phosphor plate and direct radiography or detector. In this work we have shown an application to assess automatically the constancy quality image in the image chain of the radiographic equipment. This application is integrated by designed radiographic phantoms which are adapted to conventional, dental equipment and specific developed software for the automatic evaluation of the phantom image quality. The software is based on digital image processing techniques that let the automatic detection of the different phantom tests by edge detector, morphological operators, threshold histogram techniques, etc. The utility developed is enough sensitive to the radiographic equipment of operating conditions of voltage (kV) and charge (mAs). It is a friendly user programme connected with a data base of the hospital or clinic where it has been used. After the phantom image processing the user can obtain an inform with a resume of the imaging system state with accepting and constancy results. (author)

  3. Experimental verification of dose enhancement effects in a lung phantom from inline magnetic fields.

    Science.gov (United States)

    Oborn, Bradley M; Gargett, Maegan A; Causer, Trent J; Alnaghy, Sarah J; Hardcastle, Nicholas; Metcalfe, Peter E; Keall, Paul J

    2017-12-01

    To present experimental evidence of lung dose enhancement effects caused by strong inline magnetic fields. A permanent magnet device was utilised to generate 0.95T-1.2T magnetic fields that encompassed two small lung-equivalent phantoms of density 0.3g/cm3. Small 6MV and 10MV photon beams were incident parallel with the magnetic field direction and Gafchromic EBT3 film was placed inside the lung phantoms, perpendicular to the beam (experiment 1) and parallel to the beam (experiment 2). Monte Carlo simulations of experiment 1 were also performed. Experiment 1: The 1.2T inline magnetic field induced a 12% (6MV) and 14% (10MV) increase in the dose at the phantom centre. The Monte Carlo modelling matched well (±2%) to the experimentally observed results. Experiment 2: A 0.95T field peaked at the phantom centroid (but not at the phantom entry/exit regions) details a clear dose increase due to the magnetic field of up to 25%. This experimental work has demonstrated how strong inline magnetic fields act to enhance the dose to lower density mediums such as lung tissue. Clinically, such scenarios will arise in inline MRI-linac systems for treatment of small lung tumours. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Development of an Anthropomorphic Breast Phantom for Combined PET, B-Mode Ultrasound and Elastographic Imaging

    Science.gov (United States)

    Dang, Jun; Frisch, Benjamin; Lasaygues, Philippe; Zhang, Dachun; Tavernier, Stefaan; Felix, Nicolas; Lecoq, Paul; Auffray, Etiennette; Varela, Joao; Mensah, Serge; Wan, Mingxi

    2011-06-01

    Combining the advantages of different imaging modalities leads to improved clinical results. For example, ultrasound provides good real-time structural information without any radiation and PET provides sensitive functional information. For the ongoing ClearPEM-Sonic project combining ultrasound and PET for breast imaging, we developed a dual-modality PET/Ultrasound (US) phantom. The phantom reproduces the acoustic and elastic properties of human breast tissue and allows labeling the different tissues in the phantom with different concentrations of FDG. The phantom was imaged with a whole-body PET/CT and with the Supersonic Imagine Aixplorer system. This system allows both B-mode US and shear wave elastographic imaging. US elastography is a new imaging method for displaying the tissue elasticity distribution. It was shown to be useful in breast imaging. We also tested the phantom with static elastography. A 6D magnetic positioning system allows fusing the images obtained with the two modalities. ClearPEM-Sonic is a project of the Crystal Clear Collaboration and the European Centre for Research on Medical Imaging (CERIMED).

  5. What are Asian-American youth consuming? A systematic literature review.

    Science.gov (United States)

    Diep, Cassandra S; Foster, Margaret J; McKyer, E Lisako J; Goodson, Patricia; Guidry, Jeffrey J; Liew, Jeffrey

    2015-04-01

    Numerous studies have explored dietary practices among children, but there are limited studies on children of Asian background in the US. This review had three aims: (a) review literature regarding Asian-American youth's dietary behaviors, (b) critically evaluate the methodological quality of such research, and (c) provide recommendations for future nutrition-related research on Asian-American youth. The authors conducted a systematic literature review through MEDLINE (EBSCO), CINAHL Plus with Full Text (EBSCO), and Embase (Ovid); extracted descriptive data; and evaluated methodological quality. Thirteen articles were included. Major findings included: (a) frequent consumption of milk, fruit, meat, unenriched white rice, vegetables, and high-fat and high-sugar items among Asian-American children and (b) acculturation's influences on diet, resulting in Asian-American youth consuming diets characterized by both Asian and American foods. Findings from this review may inform education and promotion programs and services for Asian Americans in the US.

  6. Tissue-mimicking bladder wall phantoms for evaluating acoustic radiation force-optical coherence elastography systems.

    Science.gov (United States)

    Ejofodomi, O'tega A; Zderic, Vesna; Zara, Jason M

    2010-04-01

    Acoustic radiation force-optical coherence elastography (ARF-OCE) systems are novel imaging systems that have the potential to simultaneously quantify and characterize the optical and mechanical properties of in vivo tissues. This article presents the construction of bladder wall phantoms for use in ARF-OCE systems. Mechanical, acoustic, and optical properties are reported and compared to published values for the urinary bladder. The phantom consisted of 0.2000 +/- 0.0089 and 6.0000 +/- 0.2830 microm polystyrene microspheres (Polysciences Inc., Warrington, PA, Catalog Nos. 07304 and 07312), 7.5 +/- 1.5 microm copolymer microspheres composed of acrylonitrile and vinylidene chloride, (Expancel, Duluth, GA, Catalog No. 461 DU 20), and bovine serum albumin within a gelatin matrix. Young's modulus was measured by successive compression of the phantom and obtaining the slope of the resulting force-displacement data. Acoustic measurements were performed using the transmission method. The phantoms were submerged in a water bath and placed between transmitting and receiving 13 mm diameter unfocused transducers operating at a frequency of 3.5 MHz. A MATLAB algorithm to extract the optical scattering coefficient from optical coherence tomography (OCT) images of the phantom was used. The phantoms possess a Young's modulus of 17.12 +/- 2.72 kPa, a mass density of 1.05 +/- 0.02 g/cm3, an acoustic attenuation coefficient of 0.66 +/- 0.08 dB/cm/MHz, a speed of sound of 1591 +/- 8.76 m/s, and an optical scattering coefficient of 1.80 +/- 0.23 mm(-1). Ultrasound and OCT images of the bladder wall phantom are presented. A material that mimics the mechanical, optical, and acoustic properties of healthy bladder wall has been developed. This tissue-mimicking bladder wall phantom was developed as a control tool to investigate the feasibility of using ARF-OCE to detect the mechanical and optical changes that may be indicative of the onset or development of cancer in the urinary bladder

  7. Oil-based gel phantom for ultrasound and optical imaging

    Science.gov (United States)

    Cabrelli, Luciana C.; Pelissari, Pedro I. B. G. B.; Aggarwal, Lucimara P.; Deana, Alessandro M.; Carneiro, Antonio A. O.; Pavan, Theo. Z.

    2015-06-01

    Water-based materials are commonly used in phantoms for ultrasound and optical imaging techniques. However, these materials have disadvantages such as easy degradation and low temporal stability. In this study, we propose an oil-based new tissue mimicking material for ultrasound and optical imaging, with the advantage of presenting low temporal degradation. Styrene-Ethylene/Butylene-Styrene (SEBS) copolymer in mineral oil samples were made varying the SEBS concentration between 5-15%, and low-density polyethylene (LDPE) between 0-9%. Acoustic properties such as speed of sound and attenuation coefficient were obtained by the substitution technique with frequencies ranging from 2.25-10 MHz, and were consistent to that of soft tissue. These properties were controlled varying SEBS and LDPE concentration; speed of sound from 1445-1480 m/s, and attenuation from 0.86-11.31 dB/cm were observed. SEBS gels with 0% of LDPE were optically transparent, presenting low optical absorption and scattering coefficients in the visible region of the spectrum. In order to fully characterize the optical properties of the samples, the reflectances of the surfaces were measured, along with the absorption. Scattering and absorption coefficients ranging from 400 nm to 1200 nm were calculated for each compound. The results showed that the presence of LDPE increased absorption and scattering of the phantoms. The results suggest the copolymer gels are promising for ultrasound and optical imaging, what make them also potentially useful for photoacoustic imaging.

  8. PIV and MRV Measurements in Human Thoracic Aorta Phantoms

    Science.gov (United States)

    Iyengar, Ananth; Elkins, Christopher; Draney, Mary; Medina, Francisco; Wicker, Ryan

    2004-11-01

    Aortic dissection is a non-traumatic injury to the aorta in which a flap is created inside the aorta by the separation of the inner lining of the vessel wall from its outer layers. It is hypothesized that dissections start as tears in vessels' inner lining and propagate as blood impinges through the tear into the separated part of the vessel wall. No two dissections are alike, but many share common characteristics, one of which is that tear sites occur in similar places in the aorta. In an effort to understand the origins of these tear sites and the propagation of dissections, we are studying blood flow in human aortas. To begin, we are using rigid aorta phantoms based on anatomies of healthy adults extracted from computed tomography (CT) and magnetic resonance imaging (MRI) medical scans. Clear polyurethane phantoms are created by casting around water-soluble positive molds manufactured using rapid prototyping. We study steady flows with Reynolds numbers comparable to those present in the aorta during the systolic pulse and physiologically pulsatile flows. The entire three-dimensional flow is measured using magnetic resonance velocimetry (MRV), a technique based on MRI principles capable of measuring three-component mean velocities. MRV results are compared to the instantaneous and average two-component velocity fields measured in a few 2D planes with particle image velocimetry (PIV). The PIV results provide validation for the MRV and insight into the instantaneous flow structures that may possibly lead to aortic dissection through fluid structure wall interaction.

  9. A two-dimensional deformable phantom for quantitatively verifying deformation algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Kirby, Neil; Chuang, Cynthia; Pouliot, Jean [Department of Radiation Oncology, University of California San Francisco, San Francisco, California 94143-1708 (United States)

    2011-08-15

    Purpose: The incorporation of deformable image registration into the treatment planning process is rapidly advancing. For this reason, the methods used to verify the underlying deformation algorithms must evolve equally fast. This manuscript proposes a two-dimensional deformable phantom, which can objectively verify the accuracy of deformation algorithms, as the next step for improving these techniques. Methods: The phantom represents a single plane of the anatomy for a head and neck patient. Inflation of a balloon catheter inside the phantom simulates tumor growth. CT and camera images of the phantom are acquired before and after its deformation. Nonradiopaque markers reside on the surface of the deformable anatomy and are visible through an acrylic plate, which enables an optical camera to measure their positions; thus, establishing the ground-truth deformation. This measured deformation is directly compared to the predictions of deformation algorithms, using several similarity metrics. The ratio of the number of points with more than a 3 mm deformation error over the number that are deformed by more than 3 mm is used for an error metric to evaluate algorithm accuracy. Results: An optical method of characterizing deformation has been successfully demonstrated. For the tests of this method, the balloon catheter deforms 32 out of the 54 surface markers by more than 3 mm. Different deformation errors result from the different similarity metrics. The most accurate deformation predictions had an error of 75%. Conclusions: The results presented here demonstrate the utility of the phantom for objectively verifying deformation algorithms and determining which is the most accurate. They also indicate that the phantom would benefit from more electron density heterogeneity. The reduction of the deformable anatomy to a two-dimensional system allows for the use of nonradiopaque markers, which do not influence deformation algorithms. This is the fundamental advantage of this

  10. Racism and Asian American Student Leadership

    Science.gov (United States)

    Chung, Jennifer Y.

    2014-01-01

    This article provides a theoretical analysis and ethnographic account of Asian American student leadership in higher education. Existing literature highlights Asian and Asian American leadership styles as cultural differences. I shift the analysis from culture to racism in order to work toward a more socially just conception of Asian American…

  11. Attenuation properties and percentage depth dose of tannin-based Rhizophora spp. particleboard phantoms using computed tomography (CT) and treatment planning system (TPS) at high energy x-ray beams

    Energy Technology Data Exchange (ETDEWEB)

    Yusof, M. F. Mohd, E-mail: mfahmi@usm.my [School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); School of Health Sciences, Universiti Sains Malaysia, 16150 Kota Bharu, Kelantan (Malaysia); Abdullah, R. [School of Health Sciences, Universiti Sains Malaysia, 16150 Kota Bharu, Kelantan (Malaysia); Tajuddin, A. A. [School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Advanced Medical and Dental Institute, Universiti Sains Malaysia, 13200 Kepala Batas, Penang (Malaysia); Hashim, R. [School of Industrial Technologies, Universiti Sains Malaysia, 11800 Penang (Malaysia); Bauk, S. [Physics Section, School of Distance Education, Universiti Sains Malaysia, 11800 Penang (Malaysia)

    2016-01-22

    A set of tannin-based Rhizophora spp. particleboard phantoms with dimension of 30 cm x 30 cm was fabricated at target density of 1.0 g/cm{sup 3}. The mass attenuation coefficient of the phantom was measured using {sup 60}Co gamma source. The phantoms were scanned using Computed Tomography (CT) scanner and the percentage depth dose (PDD) of the phantom was calculated using treatment planning system (TPS) at 6 MV and 10 MV x-ray and compared to that in solid water phantoms. The result showed that the mass attenuation coefficient of tannin-based Rhizohora spp. phantoms was near to the value of water with χ{sup 2} value of 1.2. The measured PDD also showed good agreement with solid water phantom at both 6 MV and 10 MV x-ray with percentage deviation below 8% at depth beyond the maximum dose, Z{sub max}.

  12. Attenuation properties and percentage depth dose of tannin-based Rhizophora spp. particleboard phantoms using computed tomography (CT) and treatment planning system (TPS) at high energy x-ray beams

    Science.gov (United States)

    Yusof, M. F. Mohd; Abdullah, R.; Tajuddin, A. A.; Hashim, R.; Bauk, S.

    2016-01-01

    A set of tannin-based Rhizophora spp. particleboard phantoms with dimension of 30 cm x 30 cm was fabricated at target density of 1.0 g/cm3. The mass attenuation coefficient of the phantom was measured using 60Co gamma source. The phantoms were scanned using Computed Tomography (CT) scanner and the percentage depth dose (PDD) of the phantom was calculated using treatment planning system (TPS) at 6 MV and 10 MV x-ray and compared to that in solid water phantoms. The result showed that the mass attenuation coefficient of tannin-based Rhizohora spp. phantoms was near to the value of water with χ2 value of 1.2. The measured PDD also showed good agreement with solid water phantom at both 6 MV and 10 MV x-ray with percentage deviation below 8% at depth beyond the maximum dose, Zmax.

  13. Polydimethylsiloxane tissue-mimicking phantoms for quantitative optical medical imaging standards

    Science.gov (United States)

    Hwang, Jeeseong; Kim, Hyun-Jin; Lemaillet, Paul; Wabnitz, Heidrun; Grosenick, Dirk; Yang, Lin; Gladytz, Thomas; McClatchy, David; Allen, David; Briggman, Kimberly; Pogue, Brian

    2017-03-01

    We report on a procedure to build and characterize solid tissue-mimicking phantoms of polydimethylsiloxane (PDMS) polymers. Controlled inclusion of light scattering titanium dioxide (TiO2) nanoparticles enables the creation of phantoms having tunable light scattering properties with reduced scattering coefficients consistent across different measurement platforms including an integrating sphere and a time-resolved diffuse optical spectroscopic system. Backscatter confocal microscopy is also used to characterize the shape and distribution of included TiO2 particles. The double integrating sphere and time-resolved diffuse spectroscopy were used to measure the reduced scattering coefficients of the phantoms. The results across different systems are in good agreement, suggesting that the PDMS/TiO2 composite is a promising tissue-mimicking material for developing standards useful to validate measurements by different devices for multiplatform and multi-laboratory tests.

  14. [Phantom limb pain originates from dysfunction of the primary motor cortex].

    Science.gov (United States)

    Sumitani, Masahiko; Miyauchi, Satoru; Uematsu, Hironobu; Yozu, Arito; Otake, Yuko; Yamada, Yoshitsugu

    2010-11-01

    Accumulated knowledge indicates that phantom limb pain is a phenomenon of the central nervous system that is related to plastic changes at several levels of the nervous systems. Especially, reports using patients with neuropathic pain clearly indicate the sensorimotor cortex as underlying mechanisms of phantom limb and its pain. Here, we focus the notion that limb amputation or deafferentation results in plasticity of connections between the brain and the body, and that the cortical motor representation of the missing or deafferented limb seemingly disappears. Meanwhile, the sensory representation of the limb does not disappear and thereby patients feel phantom limbs. We propose that dissociation between motor and sensory representations in the primary motor cortex induces pathologic pain and reconcile of sensorimotor integration of the limb would alleviate pain, on the basis of our neurorehabilitation approaches and artificial neuromodulation strategies.

  15. Influence of variation in eumelanin content on absorbance spectra of liquid skin-like phantoms.

    Science.gov (United States)

    Smit, Jacoba E; Grobler, Anne F; Sparrow, Raymond W

    2011-01-01

    The attenuation behavior of two different types of skin-like phantoms representing the range of Fitzpatrick skin Types I-VI was investigated and compared with real human skin. Intralipid (IL) and Pheroid(™) artificial lipid membrane vesicles, respectively, were added to synthetic eumelanin concentrations ranging from 0.0044 to 0.13mgmL(-1) to produce skin-like phantoms. Spectrophotometric absorbance and transmittance measurements were performed. Results indicated some of the nonmonotonic trends observed in real human skin, albeit shifted more toward the visible wavelength range. There exists, however, an underlying difference in interaction between the melanin and the Pheroid(™) and IL skin-like phantoms. © 2010 CSIR. Photochemistry and Photobiology © 2010 The American Society of Photobiology.

  16. Application of GEANT4 radiation transport toolkit to dose calculations in anthropomorphic phantoms

    CERN Document Server

    Rodrigues, P; Peralta, L; Alves, C; Chaves, A; Lopes, M C

    2003-01-01

    In this paper we present the implementation of a dose calculation application, based on the GEANT4 Monte Carlo toolkit. Validation studies were performed with an homogeneous water phantom and an Alderson--Rando anthropomorphic phantom both irradiated with high--energy photon beams produced by a clinical linear accelerator. As input, this tool requires computer tomography images for automatic codification of voxel based geometries and phase space distributions to characterize the incident radiation field. Simulation results were compared with ionization chamber, thermoluminescent dosimetry data and commercial treatment planning system calculations. In homogeneous water phantom, overall agreement with measurements were within 1--2%. For anthropomorphic simulated setups (thorax and head irradiation) mean differences between GEANT4 and TLD measurements were less than 2%. Significant differences between GEANT4 and a semi--analytical algorithm implemented in the treatment planning system, were found in low density ...

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

    Science.gov (United States)

    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

  18. Phantom evaluation of the effect of film processing on mammographic screen-film combinations.

    Science.gov (United States)

    McLean, D; Rickard, M T

    1994-08-01

    Mammographic image quality should be optimal for diagnosis, and the film contrast can be manipulated by altering development parameters. In this study phantom test objects were radiographed and processed for a given range of developer temperatures and times for four film-screen systems. Radiologists scored the phantom test objects on the resultant films to evaluate the effect on diagnosis of varying image contrast. While for three film-screen systems processing led to appreciable contrast differences, for only one film system did maximum contrast correspond with optimal phantom test object scoring. The inability to show an effect on diagnosis in all cases is possibly due to the variation in radiologist responses found in this study and in normal clinical circumstances. Other technical factors such as changes in film fog, grain and mottle may contribute to the study findings.

  19. Development of thyroid anthropomorphic phantoms for use in nuclear medicine

    Science.gov (United States)

    Cerqueira, R. A. D.; Maia, A. F.

    2014-02-01

    The objective of this study was to develop thyroid anthropomorphic phantoms to be used in control tests of medical images in scintillation cameras. The main difference among the phantoms was the neck shape: in the first, called OSCT, it was geometrically shaped, while in the second, called OSAP, it was anthropomorphically shaped. In both phantoms, thyroid gland prototypes, which were made of acrylic and anthropomorphically shaped, were constructed to allow the simulation of a healthy thyroid and of thyroids with hyperthyroidism and hypothyroidism. Images of these thyroid anthropomorphic phantoms were obtained using iodine 131 with an activity of 8.695 MBq. The iodine 131 was chosen because it is widely used in studies of thyroid scintigraphy. The images obtained proved the effectiveness of the phantoms to simulate normal or abnormal thyroids function. These phantoms can be used in medical imaging quality control programs and, also in the training of professionals involved in the analysis of images in nuclear medicine centers.

  20. Volumetric Intraoperative Brain Deformation Compensation: Model Development and Phantom Validation

    Science.gov (United States)

    DeLorenzo, Christine; Papademetris, Xenophon; Staib, Lawrence H.; Vives, Kenneth P.; Spencer, Dennis D.; Duncan, James S.

    2012-01-01

    During neurosurgery, nonrigid brain deformation may affect the reliability of tissue localization based on preoperative images. To provide accurate surgical guidance in these cases, preoperative images must be updated to reflect the intraoperative brain. This can be accomplished by warping these preoperative images using a biomechanical model. Due to the possible complexity of this deformation, intraoperative information is often required to guide the model solution. In this paper, a linear elastic model of the brain is developed to infer volumetric brain deformation associated with measured intraoperative cortical surface displacement. The developed model relies on known material properties of brain tissue, and does not require further knowledge about intraoperative conditions. To provide an initial estimation of volumetric model accuracy, as well as determine the model’s sensitivity to the specified material parameters and surface displacements, a realistic brain phantom was developed. Phantom results indicate that the linear elastic model significantly reduced localization error due to brain shift, from >16 mm to under 5 mm, on average. In addition, though in vivo quantitative validation is necessary, preliminary application of this approach to images acquired during neocortical epilepsy cases confirms the feasibility of applying the developed model to in vivo data. PMID:22562728

  1. Extremely sensitive dual imaging system in solid phantoms

    Science.gov (United States)

    Barnoy, Eran A.; Fixler, Dror; Popovtzer, Rachela; Nayhoz, Tsviya; Ray, Krishanu

    2016-03-01

    Herein we describe promising results from the combination of fluorescent lifetime imaging microscopy (FLIM) and diffusion reflection (DR) medical imaging techniques. Three different geometries of gold nanoparticles (GNPs) were prepared: spheres of 20nm diameter, rods (GNRs) of aspect ratio (AR) 2.5, and GNRs of AR 3.3. Each GNP geometry was then conjugated using PEG linkers estimated to be 10nm in length to each of 3 different fluorescent dyes: Fluorescein, Rhodamine B, and Sulforhodamine B. DR provided deep-volume measurements (up to 1cm) from within solid, tissue-imitating phantoms, indicating GNR presence corresponding to the light used by recording light scattered from the GNPs with increasing distance to a photodetector. FLIM imaged solutions as well as phantom surfaces, recording both the fluorescence lifetimes as well as the fluorescence intensities. Fluorescence quenching was observed for Fluorescein, while metal-enhanced fluorescence (MEF) was observed in Rhodamine B and Sulforhodamine B - the dyes with an absorption peak at a slightly longer wavelength than the GNP plasmon resonance peak. Our system is highly sensitive due to the increased intensity provided by MEF, and also because of the inherent sensitivity of both FLIM and DR. Together, these two modalities and MEF can provide a lot of meaningful information for molecular and functional imaging of biological samples.

  2. A cochlear implant phantom for evaluating CT acquisition parameters

    Science.gov (United States)

    Chakravorti, Srijata; Bussey, Brian J.; Zhao, Yiyuan; Dawant, Benoit M.; Labadie, Robert F.; Noble, Jack H.

    2017-03-01

    Cochlear Implants (CIs) are surgically implantable neural prosthetic devices used to treat profound hearing loss. Recent literature indicates that there is a correlation between the positioning of the electrode array within the cochlea and the ultimate hearing outcome of the patient, indicating that further studies aimed at better understanding the relationship between electrode position and outcomes could have significant implications for future surgical techniques, array design, and processor programming methods. Post-implantation high resolution CT imaging is the best modality for localizing electrodes and provides the resolution necessary to visually identify electrode position, albeit with an unknown degree of accuracy depending on image acquisition parameters, like the HU range of reconstruction, radiation dose, and resolution of the image. In this paper, we report on the development of a phantom that will both permit studying which CT acquisition parameters are best for accurately identifying electrode position and serve as a ground truth for evaluating how different electrode localization methods perform when using different CT scanners and acquisition parameters. We conclude based on our tests that image resolution and HU range of reconstruction strongly affect how accurately the true position of the electrode array can be found by both experts and automatic analysis techniques. The results presented in this paper demonstrate that our phantom is a versatile tool for assessing how CT acquisition parameters affect the localization of CIs.

  3. Feasibility of simultaneous PET-MR perfusion using a novel cardiac perfusion phantom

    OpenAIRE

    O'Doherty, James; SAMMUT, EVA; Schleyer, Paul; Stirling, James; Nazir, Muhummad Sohaib; Marsden, Paul K.; Chiribiri, Amedeo

    2017-01-01

    Background: PET-MR scanners are beginning to be employed for quantitative myocardial perfusion imaging. In order to examine simultaneous perfusion calculations, this work describes a feasibility study of simultaneous PET-MR of gadolinium-based contrast agent (GBCA) and PET radiotracer in a novel cardiac perfusion phantom. Results: [18F]F- and GBCA were injected simultaneously into a cardiac phantom using a range of ground-truth myocardial perfusion rates of 1 to 5 ml/g/min. PET quantification...

  4. Dosimetric analysis of SMD phototransistor in dental phantom of different geometries

    Energy Technology Data Exchange (ETDEWEB)

    Belinato, W.; Magalhaes, C. M. S.; Souza, D. N. [Departmento de Fisica, Universidade Federal de Sergipe, Av. Marechal Rondon s/n, 49.100-000, Rosa Elze, Sao Cristovao-SE (Brazil); Santos, L. A. P. [Laboratorio de Instrumentacao Nuclear, Centro Regional de Ciencias Nucleares, Av. Professor Luiz Freire, 200, 50-740-540, Recife-PE (Brazil)

    2009-10-15

    A commercial surface mount device (SMD) phototransistor, OP520, was inserted in two dental phantoms for dosimetric analysis. The irradiations were accomplished in a dental x-ray equipment of 80 kV using different exposition times. A standard ionization chamber was irradiated at the same conditions and the air kerma measured with it was compared with the electrical charge evaluated by the phototransistor. The results showed satisfactory correspondence among the detectors readings. Moreover, the phototransistor showed up quite sensitively for dental applications, allowing verifying the variations for the different phantoms configurations. (Author)

  5. SU-F-P-47: Estimation of Skin Dose by Performing the Measurements On Cylindrical Phantom

    Energy Technology Data Exchange (ETDEWEB)

    Bosma, S; Sanders, M; Aryal, P [University Kentucky - Chandler Medical Ctr, Lexington, KY (United States)

    2016-06-15

    Purpose: To evaluate the skin dose by performing the measurements on cylindrical phantom with 6X beam. Methods: A cylindrical phantom was used to best model a patient surface. The source to surface distance (SSD) was 100 cm at phantom surface along central axis (CAX). The EBT2 films were cut into 2×2 cm2 pieces. Each piece of film was placed at CAX on phantom surface for each measurement at 0°, 15°, 30°, 45°, 60°, 75°, and 90° gantry angles for field sizes of 5×5, 10×10, 15×15, and 20×20 cm{sup 2} respectively. One hundred monitor units (MU) with 6X beam were delivered for each set up. Similarly, the measurements were repeated using lithium fluoride (LiF) thermoluminescent dosimeter (TLD) chips (1X1X1 mm{sup 3}). Two TLD chips were placed for each gantry angle and field size. The calibration curves were produced for both film and TLD. The computed tomography (CT) was also performed on the same cylindrical phantom and dose was evaluated at the phantom surface using Eclipse treatment planning system ( AAA algorithm) for skin dose comparison. Results: Data showed small differences at smaller angles among EBT2, TLD and Eclipse treatment planning system. But Eclipse treatment planning system under estimated the skin dose between 20% and 50% at larger gantry angles (between 40° and 80°) at all field sizes before dose differences began to converge. Conclusion: Given this data, we can conclude that Eclipse treatment planning system under estimated the dose especially between 40 and 80 degrees of obliquity compared to the measurements results. Ideally, this study can be applied largely to head and neck patients where contours differ drastically and where skin dose is paramount.

  6. Feasibility and Validation of 4-D Pulse Wave Imaging in Phantoms and In Vivo.

    Science.gov (United States)

    Apostolakis, Iason-Zacharias; Nauleau, Pierre; Papadacci, Clement; McGarry, Matthew D; Konofagou, Elisa E

    2017-09-01

    Pulse wave imaging (PWI) is a noninvasive technique for tracking the propagation of the pulse wave along the arterial wall. The 3-D ultrasound imaging would aid in objectively estimating the pulse wave velocity (PWV) vector. This paper aims to introduce a novel PWV estimation method along the propagation direction, validate it in phantoms, and test its feasibility in vivo. A silicone vessel phantom consisting of a stiff and a soft segment along the longitudinal axis and a silicone vessel with a plaque were constructed. A 2-D array with a center frequency of 2.5 MHz was used. Propagation was successfully visualized in 3-D in each phantom and in vivo in six healthy subjects. In three of the healthy subjects, results were compared against conventional PWI using a linear array. PWVs were estimated in the stiff (3.42 ± 0.23 m [Formula: see text]) and soft (2.41 ± 0.07 m [Formula: see text]) phantom segments. Good agreement was found with the corresponding static testing values (stiff: 3.41 m [Formula: see text] and soft: 2.48 m [Formula: see text]). PWI-derived vessel compliance values were validated with dynamic testing. Comprehensive views of pulse propagation in the plaque phantom were generated and compared against conventional PWI acquisitions. Good agreement was found in vivo between the results of 4-D PWI (4.80 ± 1.32 m [Formula: see text]) and conventional PWI (4.28±1.20 m [Formula: see text]) ( n=3 ). PWVs derived for all of the healthy subjects ( n = 6 ) were within the physiological range. Thus, the 4-D PWI was successfully validated in phantoms and used to image the pulse wave propagation in normal human subjects in vivo.

  7. Dynamics of coupled phantom and tachyon fields

    Energy Technology Data Exchange (ETDEWEB)

    Shahalam, M. [Zhejiang University of Technology, Institute for Advanced Physics and Mathematics, Hangzhou (China); Pathak, S.D.; Li, Shiyuan [Shandong University, School of Physics, Jinan (China); Myrzakulov, R. [Eurasian National University, Department of General and Theoretical Physics, Eurasian International Center for Theoretical Physics, Astana (Kazakhstan); Wang, Anzhong [Zhejiang University of Technology, Institute for Advanced Physics and Mathematics, Hangzhou (China); Baylor University, Department of Physics, GCAP-CASPER, Waco, TX (United States)

    2017-10-15

    In this paper, we apply the dynamical analysis to a coupled phantom field with scaling potential taking particular forms of the coupling (linear and combination of linear), and present phase space analysis. We investigate if there exists a late time accelerated scaling attractor that has the ratio of dark energy and dark matter densities of the order one. We observe that the scrutinized couplings cannot alleviate the coincidence problem, however, they acquire stable late time accelerated solutions. We also discuss a coupled tachyon field with inverse square potential assuming linear coupling. (orig.)

  8. Getting started with PhantomJS

    CERN Document Server

    Beltran, Aries

    2013-01-01

    The book will follow aA standard tutorial approach, and will beas a complete guide detailing the major aspects of PhantomJS with particular focus on Website website Testingtesting.This book is written forIf you are a JavaScript developers who are is interested in developing applications that interact with various web services, and doing that using a headless browser, then this book is ideal for you. This book iswill also be good for you if you are planning to create a headless browser testing for your web application. Basic understanding of JavaScript is assumed.

  9. Asian Primate Species Richness Correlates with Rainfall

    OpenAIRE

    Wang, Yi-Chen; Srivathsan, Amrita; Feng, Chen-Chieh; Salim, Agus; Shekelle, Myron

    2013-01-01

    Previous studies of meta-analyses found significantly positive correlations between primate species richness and rainfall for Africa, Madagascar and the Neotropics, with the exception of Asia, leaving the open question whether that anomaly is the result of sampling bias, biogeography, or some other factor. This study re-examines the question using modelled data, with primate species richness data from the Southeast Asian Mammals Databank and rainfall data from the Climatic Research Unit. Data...

  10. Lupus among Asians and Hispanics

    Science.gov (United States)

    ... this? Submit What's this? Submit Button Past Emails Lupus among Asians and Hispanics Recommend on Facebook Tweet ... compared with white women. Signs and Symptom of Lupus Lupus can affect people of all ages. However, ...

  11. Asian American Health - Multiple Languages

    Science.gov (United States)

    ... Supplements Videos & Tools You Are Here: Home → Multiple Languages → All Health Topics → Asian American Health URL of this page: https://medlineplus.gov/languages/asianamericanhealth.html Other topics A-Z Expand Section ...

  12. Incidence of phantom limb phenomena after lower limb amputations in a Singapore tertiary hospital.

    Science.gov (United States)

    Sin, Eliza I-Lin; Thong, Sze Ying; Poon, Keah-How

    2013-02-01

    Phantom limb sensations (PLS), phantom limb pain (PLP) and stump pain (SP) are well-recognised postamputation phenomena. However, there is a dearth of related epidemiological data in Asian populations. This study was conducted to fill the information gap. Telephone interviews were conducted with patients who underwent lower limb amputations at a tertiary hospital in Singapore. Information was obtained on phantom limb characteristics, perioperative pain and functional assessment. A total of 159 patients underwent amputations over a 31-month period. At the time of the interview, 47 patients had died and 66 were contactable, of whom 49 patients were interviewed. Of these, 31 (63%) patients experienced PLS. 22 patients had postoperative pain, with 9 having both PLP and SP, 3 having PLP alone and 10 having SP alone. Among the 12 patients with PLP, at least 6 (50%) experienced constant or daily pain and 7 (58%) scored their pain as moderate-to-severe. Among those with PLP and/or SP (n = 22), 5 were distressed by the pain, 11 were on analgesics and 3 received medical follow-up. 7 (32%) patients reported functional limitations secondary to PLP or SP. Altogether, 28 (57%) patients were wheelchair or bed bound. The incidence of PLP was 25% in our cohort. Although this is lower than that reported in other studies, it remains significant, as some patients suffered moderate-to-severe pain. The difference in incidence may be due to differences in the ethnic composition and/or indications for amputation in our group. Follow-up and care could improve the outcomes in these patients.

  13. [Residual limb and phantom pain : Causes and therapeutic approaches].

    Science.gov (United States)

    Dwornik, G; Weiß, T; Hofmann, G O; Brückner, L

    2015-06-01

    Residual limb pain and phantom pain are severe complications following an amputation. Various reasons are responsible for these complaints. It must be distinguished between amputation stump pain, phantom sensations and phantom pain. In this paper we describe the most common reasons for stump pain and propose some non-operative therapeutic approaches. Furthermore path physiology and phantom pain therapy will be discussed. The recommendations offered in this paper are based on practical experience over three decades in a specialized out-patient department for patients with amputation injuries.

  14. [Phantom limb after amputation--overview and new knowledge].

    Science.gov (United States)

    Schmid, H J

    2000-01-13

    Almost all patients who have an extremity amputated will experience a phantom limb. Amputations of other parts of the body can also cause phantom sensations. One fourth of all women who undergo mastectomy relates phantom breast sensations. Phantoms are common following rectum amputation and may be significant as indicators of rectal tumor relapse. Visual phantoms can appear in patients who undergo eye amputation. Phantom phenomena occur after tooth extraction, ureterocystectomy, penectomy, plexus avulsion or spinal cord injury. The causes underlying phantom sensations are unknown. Sensory deprivation in animals causes reorganization of the cortical and subcortical maps: the areas representing the deprived input shrink and the neighbouring areas expand. The mapping allocates areas to represent the most used peripheral inputs. Every level of the nervous system seems to exhibit plasticity. The primary site seems to be the cortex. The cellular basis of plasticity is unclear. Significant sensory and motor reorganization was found in humans suffering phantom pain. There was a strong relationship between the amount of cortical reorganization and the intensity of phantom pain. These findings may influence the rehabilitation of the amputee. It was shown that pain and cortical reorganization can be reduced or even prevented by the active use of prostheses.

  15. Phantom Extremity Pain Responding to Stellate Ganglion Blockage: Case Report

    Directory of Open Access Journals (Sweden)

    Edip Gonullu

    2013-04-01

    Full Text Available Phantom extremity pain is that which continues to be felt in a non-existent extremity after amputation. The pathophysiological mechanism and etiology of phantom extremity pain are not exactly known, Phantom extremity pain affects the patients in physical and psycho-social aspects. This paper presents a patient with phantom extremity pain that had not responded to medical treatment. A stellate ganglion blockage was performed using lidocaine, bupivacaine and fentanyl and the patient%u2019s pain was observed to be reduced.

  16. Phantom Eye Syndrome: A Review of the Literature

    Directory of Open Access Journals (Sweden)

    Agda M. Andreotti

    2014-01-01

    Full Text Available The purpose of this literature review was to describe the main features of phantom eye syndrome in relation to their possible causes, symptoms, treatments, and influence of eye amputation on quality of life of anophthalmic patients. For this, a bibliographical research was performed in Pubmed database using the following terms: “eye amputation,” “eye trauma,” “phantom eye syndrome,” “phantom pain,” and “quality of life,” associated or not. Thirteen studies were selected, besides some relevant references contained in the selected manuscripts and other studies hallowed in the literature. Thus, 56 articles were included in this review. The phantom eye syndrome is defined as any sensation reported by the patient with anophthalmia, originated anophthalmic cavity. In phantom eye syndrome, at least one of these three symptoms has to be present: phantom vision, phantom pain, and phantom sensations. This syndrome has a direct influence on the quality of life of the patients, and psychological support is recommended before and after the amputation of the eyeball as well as aid in the treatment of the syndrome. Therefore, it is suggested that, for more effective treatment of phantom eye syndrome, drug therapy should be associated with psychological approach.

  17. [Gelatine phantom for training of ultrasound guided vascular access].

    Science.gov (United States)

    Clemmesen, Louise; Bendtsen, Thomas F; Sloth, Erik; Oveland, Nils Petter; Knudsen, Lars

    2013-02-25

    This article describes the production of a low-cost training phantom for ultrasound guided invasive procedures of peripheral and central veins and presents a video of the process. The phantom can be adapted for use with other ultrasound techniques. It is a universal useful skill training tool for ultrasound guided invasive procedures. The phantom is easily made of concentrated gelatine. It is cheap and recyclable. The shelf life is prolonged by cold storage in a freezer. The gelatine phantom is a useful tool for practice of probe handling techniques and needle dexterity when placing peripheral and central venous catheters.

  18. [Development of a software for 3D virtual phantom design].

    Science.gov (United States)

    Zou, Lian; Xie, Zhao; Wu, Qi

    2014-02-01

    In this paper, we present a 3D virtual phantom design software, which was developed based on object-oriented programming methodology and dedicated to medical physics research. This software was named Magical Phan tom (MPhantom), which is composed of 3D visual builder module and virtual CT scanner. The users can conveniently construct any complex 3D phantom, and then export the phantom as DICOM 3.0 CT images. MPhantom is a user-friendly and powerful software for 3D phantom configuration, and has passed the real scene's application test. MPhantom will accelerate the Monte Carlo simulation for dose calculation in radiation therapy and X ray imaging reconstruction algorithm research.

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

    Science.gov (United States)

    Poor Zamany Nejatkermany, Mahtab; Modirian, Ehsan; Soroush, Mohammadreza; Masoumi, Mehdi; Hosseini, Maryam

    2016-01-01

    To determine the frequency of phantom limb sensation (PLS) and phantom limb pain (PLP) in children and young adults suffering landmine-related amputation. 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. 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. Phantom limb sensation and pain in young survivors of landmine explosions appear to be common, even years after amputation.

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

    Science.gov (United States)

    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.

  1. Preliminary study of the 270 Bloom Fricke xylenol gel phantom performance for 3D conformal radiotherapy using multiple radiation fields

    Energy Technology Data Exchange (ETDEWEB)

    Cavinato, Christianne C.; Campos, Leticia L., E-mail: ccavinato@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (DIRF/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Gerencia de Metrologia das Radiacoes; Souza, Benedito H.; Carrete Junior, Henrique; Daros, Kellen A.C.; Medeiros, Regina B. [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Dept. de Diagnostico por Imagens; Giordani, Adelmo J. [Universidade Federal de Sao Paulo (UNIFESP), Sao Paulo, SP (Brazil). Servico de Radioterapia

    2011-07-01

    The complex cancer treatment techniques require rigorous quality control (QC). The Fricke xylenol gel (FXG) dosimeter has been studied to be applied as a three-dimensional (3D) dosimeter since it is possible to produce 3D FXG phantoms of various shapes and sizes. In this preliminary study, the performance of the FXG spherical phantom developed at IPEN, prepared using 270 Bloom gelatin from porcine skin made in Brazil, was evaluated using magnetic resonance imaging technique, aiming to use this phantom to 3D conformal radiotherapy (3DCRT) with multiple radiation fields and clinical photon beams. The obtained results indicate that for all magnetic resonance images of the FXG phantom irradiated with 6 MV clinical photon beam can be observed clearly the target volume and, in the case of coronal image, can also be observed the radiation beam projection and the overlap of different radiation fields used. The Fricke xylenol gel phantom presented satisfactory results for 3DCRT and clinical photon beams in this preliminary study. These results encourage the additional tests using complex treatment techniques and indicate the viability of applying the phantom studied to routine quality control measurements and in 3DCRT and intensity modulated radiotherapy treatment planning. (author)

  2. Teaching East and Southeast Asia through Asian Eyes

    Directory of Open Access Journals (Sweden)

    Tracy C. Barrett

    2014-06-01

    Full Text Available Colonialism and indigenous responses to its varied forms dominate modern Asian historiography and imbue the history of the region with rich and multifaceted connections to world history. As a result, the histories of East and Southeast Asian nation-states since 1500 cannot be viewed outside of the context of global affairs. Imagining Asian peoples and cultures during this time is problematic for students, who typically approach colonialism from a western perspective. This presentation explores various means of incorporating into the classroom pedagogical materials and diverse media sources that facilitate a more grounded examination of East and Southeast Asian colonies, peoples, and nation-states.It pays special attention to teaching colonialism, anti-colonialism, nationalism, and transnationalism from the perspective of Southeast Asia’s indigenous peoples.

  3. Discrimination, family relationships, and major depression among Asian Americans.

    Science.gov (United States)

    Chae, David H; Lee, Sunmin; Lincoln, Karen D; Ihara, Emily S

    2012-06-01

    Depression represents a growing concern among Asian Americans. This study examined whether discrimination and family dynamics are associated with depression in this population. Weighted logistic regressions using nationally representative data on Asian American adults (N = 2095) were used to examine associations between discrimination, negative interactions with relatives, family support, and 12-month major depressive disorder (MDD). Discrimination (odds ratio [OR] = 2.13, 95% confidence interval [CI] = 1.67, 2.71) and negative interactions with relatives (OR = 1.28, 95% CI = 1.03, 1.58) were positively associated with MDD. Family support was associated with lower MDD (OR = 0.73, 95% CI = 0.59, 0.89), and buffered lower levels of discrimination. Results suggest that discrimination may have negative mental health implications, and also point to the importance of family relationships for depression among Asian Americans. Findings suggest that providers may consider stress experienced at multiple ecological levels to address Asian American mental health needs.

  4. Rape: an Asian perspective.

    Science.gov (United States)

    Nadesan, K

    2001-06-01

    Rape is one of the fastest growing violent crimes in many parts of the world. Rape laws have been amended in most countries in an attempt to cope with the proliferation of this crime. Even though the legal definition of rape and the procedural laws have been amended, rape remains a serious problem in both the developed and developing nations. In some countries the offence of rape carries severe punishment sometimes even the death sentence. In many jurisdictions the term 'sexual penetration' is being used instead of 'sexual intercourse'. Sexual penetration includes sexual intercourse, anal intercourse, cunnilingus, fellatio or any other intrusions involving any part of a human body or of any object into the genital or anal opening of a person's body. In many countries rape and other sexual offences have been replaced with a series of gender neutral and graded offences with appropriate punishments. Medical examination can provide independent, scientific, corroborative evidence that may be of value to the court in arriving at a judgement. Doctors should have a clear understanding of different rape laws in order to apprectiate the various issues involved. Special knowledge, skill and experience are essential to conduct a good-quality medical examination. There is a dearth of trained forensic physicians in many Asian countries. However, managing a rape victim (survivor) goes for beyond proving the case in a court of law. There should be an adequate rehabilitation programme available to the victims to help them cope.

  5. Calibration phantoms for accurate water and lipid density quantification using dual energy mammography

    Science.gov (United States)

    Cho, H.-M.; Ding, H.; Kumar, N.; Sennung, D.; Molloi, S.

    2017-06-01

    The aim of this study is to investigate the feasibility of water and lipid as calibration phantoms for accurate dual energy breast density quantification. Dual energy calibration was performed on a mammography system based on scanning multi-slit Si strip photon-counting detectors using plastic water and adipose-equivalent phantoms as the basis materials. Two different methods were used to convert the dual energy decomposition measurements in plastic phantom thicknesses into the true water and lipid basis materials. The first method was based entirely on the theoretically calculated effective attenuation coefficients of the investigated materials in the mammographic energy range. The conversion matrix was determined through the linear least-squares fitting of the target material using the calculated effective attenuation coefficients of water and lipid. The second method was based on experimental calibration with plastic water phantom, adipose-equivalent phantom, and its correlation to known water and lipid thicknesses. These two methods were then validated by using an independent measurement of water and lipid mixture phantoms and postmortem breasts. The correlation between the dual energy decomposition measurements and the known values was evaluated using linear regression analysis. The averaged root-mean-square errors for water density quantification derived from the theoretical and experimental conversions were 8.6% and 1.6%, respectively. The postmortem breast tissue study also indicates that the experimentally acquired conversion coefficient improved the accuracy in water density quantification, in comparison with that from the theoretical conversion. The results show that conversion of the dual energy measurements into water and lipid thicknesses improves the accuracy in breast tissue decomposition.

  6. Multi-system comparison of optical coherence tomography performance with point spread function phantoms

    Science.gov (United States)

    Pfefer, Joshua; Fouad, Anthony; Chen, Chao-Wei; Gong, Wei; Tomlins, Peter; Woolliams, Peter; Drezek, Rebekah; Agrawal, Anant; Chen, Yu

    2013-03-01

    Point spread function (PSF) phantoms based on unstructured distributions of sub-resolution particles in a transparent matrix have proven effective for evaluating resolution and its spatial variation in optical coherence tomography (OCT) systems. Measurements based on PSF phantoms have the potential to become a standard test method for consistent, objective and quantitative inter-comparison of OCT system performance. Towards this end, we have evaluated three PSF phantoms and investigated their ability to compare the performance of four OCT systems. The phantoms are based on 260-nm-diameter gold nanoshells, submicron-diameter iron oxide particles and 1.5-micron-diameter silica particles. The OCT systems included spectral-domain and swept source systems in free-beam geometries as well as a time-domain system in both free-beam and fiberoptic probe geometries. Results indicated that iron oxide particles and gold nanoshells were most effective for measuring spatial variations in the magnitude and shape of PSFs across the image volume. The intensity of individual particles was also used to evaluate spatial variations in signal intensity uniformity. Significant system-to-system differences in resolution and signal intensity and their spatial variation were readily quantified. The phantoms proved useful for identification and characterization of irregularities such as astigmatism. Particle concentrations of 5000 per cubic millimeter or greater provided accurate determination of performance metrics. Our multi-system inter-comparison provides evidence of the effectiveness of PSF-phantom-based test methods for comparison of OCT system resolution and signal uniformity.

  7. Development of an Arm Phantom for Testing Non-Invasive Blood Pressure Monitors

    Science.gov (United States)

    Anderson-Jackson, LaTecia D.

    Approximately one in every three adults age 20 older are diagnosed with high blood pressure or hypertension. It is estimated that hypertension affects 78 million people in the United States, is equally prevalent in both men and woman (Crabtree, Stuart-Shor, & McAllister, 2013). In the United States, around 78% of people suffering from hypertension are aware of their condition, with only 68% using hypertensive medications to control their blood pressure (Writing Group et al., 2010). Clinically, blood pressure measurements may lack accuracy, which can be attributed to various factors, including device limitations, cuff mis-sizing and misplacement, white-coat effect, masked hypertension, and lifestyle factors. The development of an arm phantom to simulate physiologic properties of a human arm and arterial BP waveforms may allow us to better assess the accuracy of non-invasive blood pressure (NIBP) monitors. The objective of this study are to: (1) Develop an arm phantom to replicate physiological properties of the human arm, and (2) Incorporate the arm phantom into a mock circulatory flow loop to simulate different physiological blood pressure readings on the bench. A tissue mimicking material, styrene-ethylene-butylene-styrene (SEBS), a co-block polymer was used to develop the arm phantom for in-vitro testing. To determine the optimal mechanical properties for the arm phantom, individual arm components were isolated and tested. A protocol was developed to evaluate various components for optimal arm phantom development. Mechanical testing was conducted on 10%, 15%, and 20% SEBS gel samples for modulus of elasticity measurements in order to simulate physiological properties of the human arm. As a result of the SEBS polymer being a new material for this application, this investigation will contribute to resolving the limitations that occurred during experimentation. In this study, we demonstrated that although SEBS polymer may be an ideal material to use for simulating

  8. Simulation of images of CDMAM phantom and the estimation of measurement uncertainties of threshold gold thickness.

    Science.gov (United States)

    Mackenzie, Alistair; Eales, Timothy D; Dunn, Hannah L; Yip Braidley, Mary; Dance, David R; Young, Kenneth C

    2017-07-01

    To demonstrate a method of simulating mammography images of the CDMAM phantom and to investigate the coefficient of variation (CoV) in the threshold gold thickness (t T ) measurements associated with use of the phantom. The noise and sharpness of Hologic Dimensions and GE Essential mammography systems were characterized to provide data for the simulation. Th