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Sample records for anthropomorphic thorax phantom

  1. Development of an anthropomorphic thorax phantom for image quality control measurements in diagnostic radiology

    International Nuclear Information System (INIS)

    The use of the ionizing radiation brought by countless benefits to man. But they are associated to the current damages of radiation interaction with the body. Quality control programs of the diagnostic radiology equipment are based in the prevalence of the benefits above the damages. This program determines that tests should be done to guarantee the quality of the medical images, reducing the patients and workers absorbed doses and the cost. However, those tests cannot be made in people and it is on this moment that phantoms are used. Diagnostic radiology phantoms can be of several types, going from simple boxes to the exact representation in the human body, called anthropomorphic phantom. The aim of this study was to develop an anthropomorphic thorax phantom to be used in tests for image quality control measurements in diagnostic radiology and also for professionals' training for analysis of radiologic images. This simulator was made with natural human skeleton, heart and lungs, besides the thorax soft tissue were simulated using epoxy-resin tissue and a pair of lungs was made of foamed-polyurethane. (author)

  2. Assessing heterogeneity correction algorithms using the Radiological Physics Center's anthropomorphic thorax phantom

    International Nuclear Information System (INIS)

    The Radiological Physics Center (RPC) was established as a resource in radiation dosimetry and physics for cooperative clinical trial groups and radiotherapy facilities that deliver radiation treatments to patients entered onto cooperative group protocols. The RPC's primary responsibility is to assure NCI and the cooperative groups that the participating institutions deliver radiation treatments that are clinically comparable to those delivered by other institutions in the cooperative groups. One of the remote audit techniques used by the RPC to assure NCI is to credential institutions using its anthropomorphic phantoms, i.e. an end to end test from imaging to planning to final dose delivery as if the phantom were an actual patient. With the recent the implementation of several lung protocols requiring heterogeneity corrected target doses, the RPC, through its credentialing activities have evaluated numerous heterogeneity correction algorithms as used in various treatment planning systems. These systems include Elekta Pinnacle superposition convolution (SC) (adaptive convolve and collapsed cone) algorithms, Varian Eclipse pencil beam (PB) and AAA algorithms, TomoTherapy planning station SC, Accuray Multiplan PB and Monte Carlo (MC) algorithms, Nomos Corvus PB, CMS XiO SC, BrainLab PB and Elekta PrecisePlan Clarkson algorithm

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

    Science.gov (United States)

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

    2016-09-01

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

  4. Measurement of Entrance Surface Dose on an Anthropomorphic Thorax Phantom Using a Miniature Fiber-Optic Dosimeter

    Directory of Open Access Journals (Sweden)

    Wook Jae Yoo

    2014-04-01

    Full Text Available A miniature fiber-optic dosimeter (FOD system was fabricated using a plastic scintillating fiber, a plastic optical fiber, and a multi-pixel photon counter to measure real-time entrance surface dose (ESD during radiation diagnosis. Under varying exposure parameters of a digital radiography (DR system, we measured the scintillating light related to the ESD using the sensing probe of the FOD, which was placed at the center of the beam field on an anthropomorphic thorax phantom. Also, we obtained DR images using a flat panel detector of the DR system to evaluate the effects of the dosimeter on image artifacts during posteroanterior (PA chest radiography. From the experimental results, the scintillation output signals of the FOD were similar to the ESDs including backscatter simultaneously obtained using a semiconductor dosimeter. We demonstrated that the proposed miniature FOD can be used to measure real-time ESDs with minimization of DR image artifacts in the X-ray energy range of diagnostic radiology.

  5. Effect of reconstruction methods and x-ray tube current–time product on nodule detection in an anthropomorphic thorax phantom: A crossed-modality JAFROC observer study

    OpenAIRE

    Thompson, J D; Chakraborty, D. P.; Szczepura, K; Tootell, A K; Vamvakas, I.; Manning, D J; Hogg, P

    2016-01-01

    Purpose: To evaluate nodule detection in an anthropomorphic chest phantom in computed tomography (CT) images reconstructed with adaptive iterative dose reduction 3D (AIDR3D) and filtered back projection (FBP) over a range of tube current–time product (mAs). Methods: Two phantoms were used in this study: (i) an anthropomorphic chest phantom was loaded with spherical simulated nodules of 5, 8, 10, and 12 mm in diameter and +100, −630, and −800 Hounsfield units electron density; this would gener...

  6. Development of an anthropomorphic thorax phantom for image quality control measurements in diagnostic radiology; Construcao de um objeto simulador antropomorfico de torax para medidas de controle da qualidade da imagem em radiodiagnostico

    Energy Technology Data Exchange (ETDEWEB)

    Cerqueira, Rafaela A.D.; Maia, Ana F., E-mail: rafaelatoff@yahoo.com.b [Universidade Federal de Sergipe (DF/UFS), Sao Cristovao, SE (Brazil). Dept. de Fisica; Conceicao, Bruno M.; Teixeira, Carlos H.C.; Mota, Cleber D.; Rodrigues, Tania M.A. [Universidade Federal de Sergipe (DM/UFS), Sao Cristovao, SE (Brazil). Dept. de Morfologia

    2011-07-01

    The use of the ionizing radiation brought by countless benefits to man. But they are associated to the current damages of radiation interaction with the body. Quality control programs of the diagnostic radiology equipment are based in the prevalence of the benefits above the damages. This program determines that tests should be done to guarantee the quality of the medical images, reducing the patients and workers absorbed doses and the cost. However, those tests cannot be made in people and it is on this moment that phantoms are used. Diagnostic radiology phantoms can be of several types, going from simple boxes to the exact representation in the human body, called anthropomorphic phantom. The aim of this study was to develop an anthropomorphic thorax phantom to be used in tests for image quality control measurements in diagnostic radiology and also for professionals' training for analysis of radiologic images. This simulator was made with natural human skeleton, heart and lungs, besides the thorax soft tissue were simulated using epoxy-resin tissue and a pair of lungs was made of foamed-polyurethane. (author)

  7. A versatile variable anthropomorphic phantom

    International Nuclear Information System (INIS)

    The technique of in vivo neutron activation analysis is used in whole-body determination of some of the bulk elements. The gamma radiation emitted is compared with that from anthropomorphic phantoms containing known amounts of the elements, and matching particular patients in size and shape. An inexpensive variable phantom can be quickly constructed from between 50 and 100 very flexible sealed polythene tubes containing aqueous solutions of the elements being studied. Bundles of tubes are formed into limbs and trunk by wrapping in polythene sheeting joined with adhesive tape. Although each part maintained its size and shape over a period of a few days, distortion did occur over longer periods. It is possible to insert simulated organs or radiation probes at any position in the phantom. (U.K.)

  8. A statistically defined anthropomorphic software breast phantom

    International Nuclear Information System (INIS)

    Purpose: Digital anthropomorphic breast phantoms have emerged in the past decade because of recent advances in 3D breast x-ray imaging techniques. Computer phantoms in the literature have incorporated power-law noise to represent glandular tissue and branching structures to represent linear components such as ducts. When power-law noise is added to those phantoms in one piece, the simulated fibroglandular tissue is distributed randomly throughout the breast, resulting in dense tissue placement that may not be observed in a real breast. The authors describe a method for enhancing an existing digital anthropomorphic breast phantom by adding binarized power-law noise to a limited area of the breast. Methods: Phantoms with (0.5 mm)3 voxel size were generated using software developed by Bakic et al. Between 0% and 40% of adipose compartments in each phantom were replaced with binarized power-law noise (β = 3.0) ranging from 0.1 to 0.6 volumetric glandular fraction. The phantoms were compressed to 7.5 cm thickness, then blurred using a 3 × 3 boxcar kernel and up-sampled to (0.1 mm)3 voxel size using trilinear interpolation. Following interpolation, the phantoms were adjusted for volumetric glandular fraction using global thresholding. Monoenergetic phantom projections were created, including quantum noise and simulated detector blur. Texture was quantified in the simulated projections using power-spectrum analysis to estimate the power-law exponent β from 25.6 × 25.6 mm2 regions of interest. Results: Phantoms were generated with total volumetric glandular fraction ranging from 3% to 24%. Values for β (averaged per projection view) were found to be between 2.67 and 3.73. Thus, the range of textures of the simulated breasts covers the textures observed in clinical images. Conclusions: Using these new techniques, digital anthropomorphic breast phantoms can be generated with a variety of glandular fractions and patterns. β values for this new phantom are comparable

  9. Synthesized interstitial lung texture for use in anthropomorphic computational phantoms

    Science.gov (United States)

    Becchetti, Marc F.; Solomon, Justin B.; Segars, W. Paul; Samei, Ehsan

    2016-04-01

    A realistic model of the anatomical texture from the pulmonary interstitium was developed with the goal of extending the capability of anthropomorphic computational phantoms (e.g., XCAT, Duke University), allowing for more accurate image quality assessment. Contrast-enhanced, high dose, thorax images for a healthy patient from a clinical CT system (Discovery CT750HD, GE healthcare) with thin (0.625 mm) slices and filtered back- projection (FBP) were used to inform the model. The interstitium which gives rise to the texture was defined using 24 volumes of interest (VOIs). These VOIs were selected manually to avoid vasculature, bronchi, and bronchioles. A small scale Hessian-based line filter was applied to minimize the amount of partial-volumed supernumerary vessels and bronchioles within the VOIs. The texture in the VOIs was characterized using 8 Haralick and 13 gray-level run length features. A clustered lumpy background (CLB) model with added noise and blurring to match CT system was optimized to resemble the texture in the VOIs using a genetic algorithm with the Mahalanobis distance as a similarity metric between the texture features. The most similar CLB model was then used to generate the interstitial texture to fill the lung. The optimization improved the similarity by 45%. This will substantially enhance the capabilities of anthropomorphic computational phantoms, allowing for more realistic CT simulations.

  10. Quality Assurance in Radiotherapy with Anthropomorphic Phantoms

    International Nuclear Information System (INIS)

    Modern conformal treatment planning and delivery, using techniques such as 3-D conformal radiotherapy, intensity modulated radiotherapy and stereotactic body radiotherapy require multiple procedures before the delivery of the prescribed dose. Imaging of the patient, identification of target volumes and organs at risk, calculation of the optimal dose distribution and even quality assurance procedures before the treatment are part of this process. Each step as well as the delivery of the final plan is vulnerable to errors. Anthropomorphic phantoms have been designed to simulate patient anatomy to evaluate treatment planning and delivery. They are mailable, filled with water on site, and contain targets and organs at risk with densities and dimensions similar to human anatomy. Dosimeters are included for the analysis of dose distributions. An analysis of irradiations performed at multiple institutions that failed to meet acceptance criteria is presented. With five distinct designs to perform tests at different body sites and almost ten years of experience, the use of these phantoms allows the identification of errors in the modelling of the beam by the treatment planning system, inaccuracies in dose calculation methods when heterogeneities are taken into account and positioning errors. These phantoms are powerful tools for quality assurance and verification of the treatment delivered to a patient from CT table to treatment couch. (author)

  11. Development of thyroid anthropomorphic phantoms for use in nuclear medicine

    International Nuclear Information System (INIS)

    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. - Highlights: ► Two thyroid phantoms were developed (OSCT and OSAP) with different types of acrylics. ► Thyroid glands were represented anthropomorphically in the both phantoms. ► Different prototypes of thyroid were built of simulate healthy or unhealthy glands. ► Images indicate that anthropomorphic phantoms correctly simulate the thyroid gland

  12. Characterisation of an anthropomorphic chest phantom for dose measurements in radiology beams

    Science.gov (United States)

    Henriques, L. M. S.; Cerqueira, R. A. D.; Santos, W. S.; Pereira, A. J. S.; Rodrigues, T. M. A.; Carvalho Júnior, A. B.; Maia, A. F.

    2014-02-01

    The objective of this study was to characterise an anthropomorphic chest phantom for dosimetric measurements of conventional radiology beams. This phantom was developed by a previous research project at the Federal University of Sergipe for image quality control tests. As the phantom consists of tissue-equivalent material, it is possible to characterise it for dosimetric studies. For comparison, a geometric chest phantom, consisting of PMMA (polymethylmethacrylate) with dimensions of 30×30×15 cm³ was used. Measurements of incident air kerma (Ki) and entrance surface dose (ESD) were performed using ionisation chambers. From the results, backscatter factors (BSFs) of the two phantoms were determined and compared with values estimated by CALDose_X software, based on a Monte Carlo simulation. For the technical parameters evaluated in this study, the ESD and BSF values obtained experimentally showed a good similarity between the two phantoms, with minimum and maximum difference of 0.2% and 7.0%, respectively, and showed good agreement with the results published in the literature. Organ doses and effective doses for the anthropomorphic phantom were also estimated by the determination of conversion coefficients (CCs) using the visual Monte Carlo (VMC) code. Therefore, the results of this study prove that the anthropomorphic thorax phantom proposed is a good tool to use in dosimetry and can be used for risk evaluation of X-ray diagnostic procedures.

  13. 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 ...

  14. 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 892.1370 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1370 Nuclear anthropomorphic...

  15. Credentialing for advanced technology clinical trials using anthropomorphic phantoms

    International Nuclear Information System (INIS)

    's equipment and QA procedures. The credentialing programme also requires the institution to prepare a treatment plan that is compliant with the requirements of the protocol, and submit the plan, most often through an electronic digital data exchange process. The programme also requires the institution to irradiate a standardized anthropomorphic QA phantom. To meet the anthropomorphic QA phantom irradiation requirement, the RPC has designed and constructed a family of anthropomorphic phantoms that have now been used to credential more than 304 institutions for advanced technology clinical trials. These QA phantoms are water-filled plastic shells with imageable targets, avoidance structures, and heterogeneities. The phantoms contain TLD and radiochromic film dosimeters, to record the dose delivered by the institution. Phantoms have been constructed that represent 1) the head, for SRS brain trials; 2) the head and neck, for IMRT trials; 3) the thorax, for SRS treatment of lung tumours; (4) the abdomen, for SRS treatment of small tumours in organs such as the liver; and (5) the pelvis, for IMRT treatments of the prostate and cervix. The abdomen phantom is unique in that it contains two targets within the liver structure and three organs at risk (OAR); the stomach, kidney and spine. This phantom is placed on a 2D reciprocating table to simulate respiratory motion in the AP and SI directions. When an institution requests to participate in a clinical trial that requires a phantom irradiation, a phantom is shipped by overnight express to the institution. Upon receipt of the phantom, the institution must first fill the phantom with water and install the imaging and dosimetry inserts, if appropriate. The institution is instructed to perform their routine CT imaging/simulation procedures, and prepare a treatment plan according to instructions given them, which are consistent with the requirements of the clinical trial. Next, the institution is to transfer the phantom to the treatment

  16. Characterization of a novel anthropomorphic plastinated lung phantom

    OpenAIRE

    Yoon, Sungwon; Henry, Robert W.; Bouley, Donna M.; Bennett, N. Robert; Fahrig, Rebecca

    2008-01-01

    Phantoms are widely used during the development of new imaging systems and algorithms. For development and optimization of new imaging systems such as tomosynthesis, where conventional image quality metrics may not be applicable, a realistic phantom that can be used across imaging systems is desirable. A novel anthropomorphic lung phantom was developed by plastination of an actual pig lung. The plastinated phantom is characterized and compared with reference to in vivo images of the same tiss...

  17. Development of a physical 3D anthropomorphic breast phantom

    International Nuclear Information System (INIS)

    Purpose: Develop a technique to fabricate a 3D anthropomorphic breast phantom with known ground truth for image quality assessment of 2D and 3D breast x-ray imaging systems. Methods: The phantom design is based on an existing computer model that can generate breast voxel phantoms of varying composition, size, and shape. The physical phantom is produced in two steps. First, the portion of the voxel phantom consisting of the glandular tissue, skin, and Cooper's ligaments is separated into sections. These sections are then fabricated by high-resolution rapid prototyping using a single material with 50% glandular equivalence. The remaining adipose compartments are then filled using an epoxy-based resin (EBR) with 100% adipose equivalence. The phantom sections are stacked to form the physical anthropomorphic phantom. Results: The authors fabricated a prototype phantom corresponding to a 450 ml breast with 45% dense tissue, deformed to a 5 cm compressed thickness. Both the rapid prototype (RP) and EBR phantom materials are radiographically uniform. The coefficient of variation (CoV) of the relative attenuation between RP and EBR phantom samples was <1% and the CoV of the signal intensity within RP and EBR phantom samples was <1.5% on average. Digital mammography and reconstructed digital breast tomosynthesis images of the authors' phantom were reviewed by two radiologists; they reported that the images are similar in appearance to clinical images, noting there are still artifacts from air bubbles in the EBR. Conclusions: The authors have developed a technique to produce 3D anthropomorphic breast phantoms with known ground truth, yielding highly realistic x-ray images. Such phantoms may serve both qualitative and quantitative performance assessments for 2D and 3D breast x-ray imaging systems.

  18. Characterization of a novel anthropomorphic plastinated lung phantom.

    Science.gov (United States)

    Yoon, Sungwon; Henry, Robert W; Bouley, Donna M; Bennett, N Robert; Fahrig, Rebecca

    2008-12-01

    Phantoms are widely used during the development of new imaging systems and algorithms. For development and optimization of new imaging systems such as tomosynthesis, where conventional image quality metrics may not be applicable, a realistic phantom that can be used across imaging systems is desirable. A novel anthropomorphic lung phantom was developed by plastination of an actual pig lung. The plastinated phantom is characterized and compared with reference to in vivo images of the same tissue prior to plastination using high resolution 3D CT. The phantom is stable over time and preserves the anatomical features and relative locations of the in vivo sample. The volumes for different tissue types in the phantom are comparable to the in vivo counterparts, and CT numbers for different tissue types fall within a clinically useful range. Based on the measured CT numbers, the phantom cardiac tissue experienced a 92% decrease in bulk density and the phantom pulmonary tissue experienced a 78% decrease in bulk density compared to their in vivo counterparts. By-products in the phantom from the room temperature vulcanizing silicone and plastination process are also identified. A second generation phantom, which eliminates most of the by-products, is presented. Such anthropomorphic phantoms can be used to evaluate a wide range of novel imaging systems. PMID:19175148

  19. Attributes of a real and computational female thorax phantom for dosimetry

    International Nuclear Information System (INIS)

    This work describes the construction of an anatomic model that keeps the anthropometrics and anthropomorphic relations of human thorax. The work was developed in two stages. The first one is the construction of a real phantom. The second stage discusses a computational pattern. Due to the large use of ionizing radiation in medical area, the creation of a simulator, the more approximate as possible to the human pattern, proved to be useful. The purpose of the simulator was to contribute to minimizing miscalculation in human treatment procedures, to improve medical image quality and even to serve an academic purposes as a pedagogic pattern. The phantom's construction process was totally handicraft and developed in several stages, which are described as well as the used equivalent materials. The following elements were constructed: twelve thorax vertebras, twenty four ribs, two shoulder blades, two collarbones and the external bone. Also the equivalent muscular tissue, the skin and the mammary gland were built. To create the mammary gland, a plastic prosthesis filled with equivalent mammary tissue was used. Meantime, an anatomic three dimensional model was made to simulate the human thorax. A bone skeleton covered by a muscular and a skin coat composed it. The breast was coupled in anatomic position on left hemi thorax. Computed tomography (CT) images were taken to verify the similarity of density tissue when it was compared to human model. This work was photographically recorded during all stages. The computational thorax phantom was based on a digitalized tomography - in a colored voxels model, each entity represents one tissue and each tissue shows a specific color. The model valuates the density and chemical composition of the tissue. As to the images treatment, a network Internet computer program specially developed for SISCODES was used to support it. In the future this model will be useful to dosimetric studies, medical image equipment calibration, and new

  20. 21 CFR 892.1950 - Radiographic anthropomorphic phantom.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiographic anthropomorphic phantom. 892.1950 Section 892.1950 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1950 Radiographic...

  1. 3D printer generated thorax phantom with mobile tumor for radiation dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, Rulon [Henry Jackson Foundation, Bethesda, Maryland 20817 (United States); Liacouras, Peter [Walter Reed National Military Medical Center, Bethesda, Maryland 20899 (United States); Thomas, Andrew [ATC Healthcare, Washington, District of Columbia 20006 (United States); Kang, Minglei; Lin, Liyong; Simone, Charles B. [Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States)

    2015-07-15

    This article describes the design, construction, and properties of an anthropomorphic thorax phantom with a moving surrogate tumor. This novel phantom permits detection of dose both inside and outside a moving tumor and within the substitute lung tissue material. A 3D printer generated the thorax shell composed of a chest wall, spinal column, and posterior regions of the phantom. Images of a computed tomography scan of the thorax from a patient with lung cancer provided the template for the 3D printing. The plastic phantom is segmented into two materials representing the muscle and bones, and its geometry closely matches a patient. A surrogate spherical plastic tumor controlled by a 3D linear stage simulates a lung tumor’s trajectory during normal breathing. Sawdust emulates the lung tissue in terms of average and distribution in Hounsfield numbers. The sawdust also provides a forgiving medium that permits tumor motion and sandwiching of radiochromic film inside the mobile surrogate plastic tumor for dosimetry. A custom cork casing shields the film and tumor and eliminates film bending during extended scans. The phantom, lung tissue surrogate, and radiochromic film are exposed to a seven field plan based on an ECLIPSE plan for 6 MV photons from a Trilogy machine delivering 230 cGy to the isocenter. The dose collected in a sagittal plane is compared to the calculated plan. Gamma analysis finds 8.8% and 5.5% gamma failure rates for measurements of large amplitude trajectory and static measurements relative to the large amplitude plan, respectively. These particular gamma analysis results were achieved using parameters of 3% dose and 3 mm, for regions receiving doses >150 cGy. The plan assumes a stationary detection grid unlike the moving radiochromic film and tissues. This difference was experimentally observed and motivated calculated dose distributions that incorporated the phase of the tumor periodic motion. These calculations modestly improve agreement between

  2. 3D printer generated thorax phantom with mobile tumor for radiation dosimetry

    Science.gov (United States)

    Mayer, Rulon; Liacouras, Peter; Thomas, Andrew; Kang, Minglei; Lin, Liyong; Simone, Charles B.

    2015-07-01

    This article describes the design, construction, and properties of an anthropomorphic thorax phantom with a moving surrogate tumor. This novel phantom permits detection of dose both inside and outside a moving tumor and within the substitute lung tissue material. A 3D printer generated the thorax shell composed of a chest wall, spinal column, and posterior regions of the phantom. Images of a computed tomography scan of the thorax from a patient with lung cancer provided the template for the 3D printing. The plastic phantom is segmented into two materials representing the muscle and bones, and its geometry closely matches a patient. A surrogate spherical plastic tumor controlled by a 3D linear stage simulates a lung tumor's trajectory during normal breathing. Sawdust emulates the lung tissue in terms of average and distribution in Hounsfield numbers. The sawdust also provides a forgiving medium that permits tumor motion and sandwiching of radiochromic film inside the mobile surrogate plastic tumor for dosimetry. A custom cork casing shields the film and tumor and eliminates film bending during extended scans. The phantom, lung tissue surrogate, and radiochromic film are exposed to a seven field plan based on an ECLIPSE plan for 6 MV photons from a Trilogy machine delivering 230 cGy to the isocenter. The dose collected in a sagittal plane is compared to the calculated plan. Gamma analysis finds 8.8% and 5.5% gamma failure rates for measurements of large amplitude trajectory and static measurements relative to the large amplitude plan, respectively. These particular gamma analysis results were achieved using parameters of 3% dose and 3 mm, for regions receiving doses >150 cGy. The plan assumes a stationary detection grid unlike the moving radiochromic film and tissues. This difference was experimentally observed and motivated calculated dose distributions that incorporated the phase of the tumor periodic motion. These calculations modestly improve agreement between

  3. 3D printer generated thorax phantom with mobile tumor for radiation dosimetry

    International Nuclear Information System (INIS)

    This article describes the design, construction, and properties of an anthropomorphic thorax phantom with a moving surrogate tumor. This novel phantom permits detection of dose both inside and outside a moving tumor and within the substitute lung tissue material. A 3D printer generated the thorax shell composed of a chest wall, spinal column, and posterior regions of the phantom. Images of a computed tomography scan of the thorax from a patient with lung cancer provided the template for the 3D printing. The plastic phantom is segmented into two materials representing the muscle and bones, and its geometry closely matches a patient. A surrogate spherical plastic tumor controlled by a 3D linear stage simulates a lung tumor’s trajectory during normal breathing. Sawdust emulates the lung tissue in terms of average and distribution in Hounsfield numbers. The sawdust also provides a forgiving medium that permits tumor motion and sandwiching of radiochromic film inside the mobile surrogate plastic tumor for dosimetry. A custom cork casing shields the film and tumor and eliminates film bending during extended scans. The phantom, lung tissue surrogate, and radiochromic film are exposed to a seven field plan based on an ECLIPSE plan for 6 MV photons from a Trilogy machine delivering 230 cGy to the isocenter. The dose collected in a sagittal plane is compared to the calculated plan. Gamma analysis finds 8.8% and 5.5% gamma failure rates for measurements of large amplitude trajectory and static measurements relative to the large amplitude plan, respectively. These particular gamma analysis results were achieved using parameters of 3% dose and 3 mm, for regions receiving doses >150 cGy. The plan assumes a stationary detection grid unlike the moving radiochromic film and tissues. This difference was experimentally observed and motivated calculated dose distributions that incorporated the phase of the tumor periodic motion. These calculations modestly improve agreement between

  4. Computational anthropomorphic phantoms for radiation protection dosimetry: evolution and prospects

    International Nuclear Information System (INIS)

    Computational anthropomorphic phantoms are computer models of human anatomy used in the calculation of radiation dose distribution in the human body upon exposure to a radiation source. Depending on the manner to represent human anatomy, they are categorized into two classes: stylized and tomographic phantoms. Stylized phantoms, which have mainly been developed at the Oak Ridge National Laboratory (ORNL), describe human anatomy by using simple mathematical equations of analytical geometry. Several improved stylized phantoms such as male and female adults, pediatric series, and enhanced organ models have been developed following the first hermaphrodite adult stylized phantom, Medical Internal Radiation Dose (MIRD)-5 phantom. Although stylized phantoms have significantly contributed to dosimetry calculation, they provide only approximations of the true anatomical features of the human body and the resulting organ dose distribution. An alternative class of computational phantom, the tomographic phantom, is based upon three-dimensional imaging techniques such as Magnetic Resonance (MR) imaging and Computed Tomography (CT). The tomographic phantoms represent the human anatomy with a large number of voxels that are assigned tissue type and organ identity. To date, a total of around 30 tomographic phantoms including male and female adults, pediatric phantoms, and even a pregnant female, have been developed and utilized for realistic radiation dosimetry calculation. They are based on MRI/CT images or sectional color photos from patients, volunteers or cadavers. Several investigators have compared tomographic phantoms with stylized phantoms, and demonstrated the superiority of tomographic phantoms in terms of realistic anatomy and dosimetry calculation. This paper summarizes the history and current status of both stylized and tomographic phantoms, including Korean computational phantoms. Advantages, limitations, and future prospects are also discussed

  5. Optimized generation of high resolution breast anthropomorphic software phantoms

    International Nuclear Information System (INIS)

    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.

  6. OSL Based Anthropomorphic Phantom and Real-Time Organ Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    David E. Hintenlang, Ph.D

    2009-02-10

    The overall objective of this project was the development of a dosimetry system that provides the direct measurement of organ does in real-time with a sensitivity that makes it an effective tool for applications in a wide variety of health physics applications. The system included the development of a real-time readout system for fiber optic coupled (FOC) dosimeters that is integrated with a state-of-art anthropomorphic phantom to provide instantaneous measures of organ doses throughout the phantom. The small size of the FOC detectors and optical fibers allow the sensitive volume of the detector to be located at organ centroids (or multiple locations distributed through the organ) within a tissue equivalent, anthropomorphic phantom without perturbing the tissue equivalent features of the phantom. The developed phantom/dosimetry system can be used in any environment where personnel may be exposed to gamma or x-ray radiations to provide the most accurate determinations of organ and effective doses possible to date.

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

    International Nuclear Information System (INIS)

    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

  8. 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

  9. Experimental validation of a kV source model and dose computation method for CBCT imaging in an anthropomorphic phantom.

    Science.gov (United States)

    Poirier, Yannick; Tambasco, Mauro

    2016-01-01

    We present an experimental validation of a kilovoltage (kV) X-ray source characterization model in an anthropomorphic phantom to estimate patient-specific absorbed dose from kV cone-beam computed tomography (CBCT) imaging procedures and compare these doses to nominal weighted CT-dose index (CTDIw) dose estimates. We simulated the default Varian on-board imager 1.4 (OBI) default CBCT imaging protocols (i.e., standard-dose head, low-dose thorax, pelvis, and pelvis spotlight) using our previously developed and easy to implement X-ray point-source model and source characterization approach. We used this characterized source model to compute absorbed dose in homogeneous and anthropomorphic phantoms using our previously validated in-house kV dose computation software (kVDoseCalc). We compared these computed absorbed doses to doses derived from ionization chamber measurements acquired at several points in a homogeneous cylindrical phantom and from thermoluminescent detectors (TLDs) placed in the anthropomorphic phantom. In the homogeneous cylindrical phantom, computed values of absorbed dose relative to the center of the phantom agreed with measured values within ≤2% of local dose, except in regions of high-dose gradient where the distance to agreement (DTA) was 2 mm. The computed absorbed dose in the anthropomorphic phantom generally agreed with TLD measurements, with an average percent dose difference ranging from 2.4% ± 6.0% to 5.7% ± 10.3%, depending on the characterized CBCT imaging protocol. The low-dose thorax and the standard dose scans showed the best and worst agreement, respectively. Our results also broadly agree with published values, which are approximately twice as high as the nominal CTDIw would suggest. The results demonstrate that our previously developed method for modeling and characterizing a kV X-ray source could be used to accurately assess patient-specific absorbed dose from kV CBCT procedures within reasonable accuracy, and serve as further

  10. Calcium scoring with dual-energy CT in men and women: an anthropomorphic phantom study

    Science.gov (United States)

    Li, Qin; Liu, Songtao; Myers, Kyle; Gavrielides, Marios A.; Zeng, Rongping; Sahiner, Berkman; Petrick, Nicholas

    2016-03-01

    This work aimed to quantify and compare the potential impact of gender differences on coronary artery calcium scoring with dual-energy CT. An anthropomorphic thorax phantom with four synthetic heart vessels (diameter 3-4.5 mm: female/male left main and left circumflex artery) were scanned with and without female breast plates. Ten repeat scans were acquired in both single- and dual-energy modes and reconstructed at six reconstruction settings: two slice thicknesses (3 mm, 0.6 mm) and three reconstruction algorithms (FBP, IR3, IR5). Agatston and calcium volume scores were estimated from the reconstructed data using a segmentation-based approach. Total calcium score (summation of four vessels), and male/female calcium scores (summation of male/female vessels scanned in phantom without/with breast plates) were calculated accordingly. Both Agatston and calcium volume scores were found comparable between single- and dual-energy scans (Pearson r= 0.99, pimaging protocols for improved gender-specific calcium scoring.

  11. Long-term dose measurements applying a human anthropomorphic phantom onboard an aircraft

    International Nuclear Information System (INIS)

    The exposure of aircrew personnel to cosmic radiation has been considered as occupational exposure in the European Union since the European Council Directive 96/26/EURATOM became effective on 13th May 1996. In Germany the corresponding safety standards for aircrew are regulated by the German Radiation Protection Ordinance, which implemented the European law in 2001. The radiation exposure of the flight crew of the LUFTHANSA group is calculated by the DLR Institute of Aerospace Medicine in Cologne, applying the calculation program EPCARD in the framework of the aircrew dose determination system CALculated and Verified Aviation DOSimetry (CALVADOS). Besides the operational dose calculations, DLR performs measurements at airflight altitudes using active (e.g. TEPC, DOSTEL, etc.) and passive (Thermoluminescence detectors (TLDs), bubble detectors) radiation detectors to verify the calculation codes. Within these activities the project BOdy DOsimetry (BODO) comprised a long-term exposure of a RANDO anthropomorphic phantom to measure the skin and the depth dose distribution inside a human torso applying TLDs at aviation altitudes for the first time. The torso was flown onboard a LUFTHANSA Cargo aircraft for 3 months from mid of July to mid of October 2004. Over 800 TLDs were positioned for depth dose measurements in the head, the thorax and the abdomen of the torso. In addition dosemeter packages have been distributed on the surface of the torso to measure the skin dose as well as in the transport container and on the flight deck

  12. Optimization of a protocol for myocardial perfusion scintigraphy by using an anthropomorphic phantom

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, Susie Medeiros Oliveira; Sa, Lidia Vasconcellos de, E-mail: susie@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Glavam, Adriana Pereira; Kubo, Tadeu Takao Almodovar [Clinica de Diagnostico Por Imagem (CDPI/DASA), Rio de Janeiro, RJ (Brazil)

    2014-07-15

    Objective: to develop a study aiming at optimizing myocardial perfusion imaging. Materials and Methods: imaging of an anthropomorphic thorax phantom with a GE SPECT Ventri gamma camera, with varied activities and acquisition times, in order to evaluate the influence of these parameters on the quality of the reconstructed medical images. The {sup 99m}Tc-sestamibi radiotracer was utilized, and then the images were clinically evaluated on the basis of data such as summed stress score, and on the technical image quality and perfusion. The software ImageJ was utilized in the data quantification. Results: the results demonstrated that for the standard acquisition time utilized in the procedure (15 seconds per angle), the injected activity could be reduced by 33.34%. Additionally, even if the standard scan time is reduced by 53.34% (7 seconds per angle), the standard injected activity could still be reduced by 16.67%, without impairing the image quality and the diagnostic reliability. Conclusion: the described method and respective results provide a basis for the development of a clinical trial of patients in an optimized protocol. (author)

  13. Location of radiosensitive organs, measurement of absorbed dose to radiosensitive organs and use of bismuth shields in paediatric anthropomorphic phantoms

    International Nuclear Information System (INIS)

    The aim of this study was to investigate: firstly, (i) location of radiosensitive organs in the interior of four (4) paediatric anthropomorphic phantoms, and, secondly, (ii) effectiveness of single and double bismuth thyroid shields, distance between shield and phantom surface, during paediatric multi-detector computed tomography (MDCT) using fixed tube current (FTC) and automatic exposure control (AEC) on dose reduction and image quality. Four (4) paediatric anthropomorphic phantoms representing the equivalent of a newborn, 1-, 5-, and 10-y-old child underwent head, thorax and abdomen computed tomography (CT) scans. CT and magnetic resonance imaging scans of all children aged 0-16 y-old performed during a 5-y-period at the University Hospital of Heraklion, Crete, Greece were reviewed, and five hundred and three (503) were found to be eligible for normal anatomy. Anterior-posterior and lateral dimensions of twelve (12) of the above children closely matched that of the phantoms' thoracic and abdominal region in each four (4) phantoms. The mid-sagittal plane (MSP) and mid-coronal plane (MCP) were drawn on selected matching axial images of patients and phantoms. Multiple points outlining large radiosensitive organs and centres of small organs in patient images were identified at each slice level and their orthogonal distances from the MSP and MCP were measured. The outlines and centres of all radiosensitive organs were reproduced using the coordinates of each organ on the corresponding phantom's transverse images. The four (4) phantoms were also subjected to routine head and neck, neck and thorax CT scans on a 16-slice CT system. Each phantom was first scanned with both FTC and AEC for with and without bismuth shields. Each scan was repeated ten (10) times to increase thermoluminescent dosimeters (TLDs) signal and reduce measurement statistical error. For neck CT, the effect of using single and double thickness of bismuth shields and 1-3 cm cotton spacers

  14. An anthropomorphic pelvis phantom for optimization of the diagnosis of lymph node metastases in the pelvis

    International Nuclear Information System (INIS)

    An anthropomorphic pelvis phantom was made by the modification of a National Electrical Manufacturers Association (NEMA) phantom, currently the most popular one, and its clinical usefulness was evaluated. The NEMA plus bone phantom was made by placing the pelvic bone model in the NEMA phantom. The NEMA plus bladder phantom was made by placing an imitation of the urinary bladder in the NEMA phantom. The pelvis phantom was also made by placing both the pelvic bone model and the bladder in the NEMA phantom. Four kinds of phantoms were imaged by both 2D and 3D dynamic modes, and for each phantom, prompt coincidence count rates, random ones, true plus scatter ones, and single photon rates were measured and these coincidence count rates were compared with those from the actual clinical data. After image reconstruction, the contrast ratio and image noise were also investigated. For the random coincidence count rate, the data obtained from each phantom showed good correspondence to the clinical data. The prompt coincidence count rates and true plus scatter ones of the clinical data were different from those obtained from NEMA phantom, NEMA plus bone one and NEMA plus bladder one, whereas there was a good correspondence between the data of the pelvis phantom and the clinical data. For the contrast ratio and image noise, there were discrepancies between the data of NEMA phantom and pelvis phantoms. We made an anthropomorphic pelvis phantom by the simple modification of a NEMA phantom. This phantom showed performance similar to that of the actual human pelvis, suggesting clinical usefulness in the evaluation of new acquisition protocols and reconstruction algorithms. (author)

  15. Development of an anthropomorphic head phantom using dolomite and polymethyl methacrylate for dosimetry in computed tomography

    Science.gov (United States)

    Ximenes, R. E.; Silva, A.; Balbino, D.; Poletti, M. E.; Maia, A. F.

    2015-12-01

    A real human skull was selected to be a mold for the construction of an anthropomorphic head phantom with a mixture of dolomite and polymethyl methacrylate (PMMA). Using linear attenuation coefficients, we show that it is possible to use dolomite as a bone simulator as long as the proportion of the mixture is 1:1. Acrylic tubes were placed in the phantom constructed to enable the insertion of the ionization chamber to estimate the effective dose. Values for a typical head computed tomography examination found in the literature vary from 0.9 to 4.0 mSv. Dosimetric studies showed that the effective dose for the anthropomorphic phantom was (2.70±0.03) mSv and for the geometric PMMA phantom (3.67±0.04) mSv, values which are in agreement with the intervals reported in the literature. The investment to produce the phantom was approximately US160.00.

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

    International Nuclear Information System (INIS)

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

  17. Thorax; Thorax

    Energy Technology Data Exchange (ETDEWEB)

    Galanski, Michael; Dettmer, Sabine; Opherk, Jan Patrick; Ringe, Kristina [Medizinische Hochschule Hannover (Germany). Inst. fuer Radiologie; Keberle, Marc [Bruederkrankenhaus St. Josef, Paderborn (Germany). Klinik fuer Diagnostische Radiologie und Nuklearmedizin

    2010-07-01

    The book on thorax radiology covers the following topics: congenital diseases, respiratory system diseases, work-related diseases, infections, interstitial pneumonia, vascular diseases, immunological unclear diseases, bronchopulmonal neoplasm, lung diseases, mediastinum, thorax and pleura, thorax trauma, therapy consequences.

  18. Construction of a anthropomorphic phantom for dose measurement in hands in brachytherapy procedures

    International Nuclear Information System (INIS)

    The main objective of this work was to show the differences between the dose value measured by dosimeter endpoint and the values measured in different points inside the hand during brachytherapy procedures. For this, the procedures involved in the handling of sources were analyzed and the simulated using an anthropomorphic phantom hand

  19. Development of a 3D high-resolution physical anthropomorphic breast phantom

    Science.gov (United States)

    Carton, Ann-Katherine; Bakic, Predrag; Ullberg, Christer; Maidment, Andrew D. A.

    2010-04-01

    Analysis of complex imaging tasks requires a phantom that simulates the patient anatomy. We have developed a technique to fabricate 3D physical anthropomorphic breast phantoms for image quality assessment of 2D and 3D breast x-ray imaging systems. The phantom design is based on an existing computer model that can generate breast voxel phantoms of varying size, shape, glandularity, and internal composition. The physical phantom is produced in two steps. First, the computer model of the glandular tissue, skin and Coopers' ligaments is separated into sections. These sections are fabricated by high-resolution rapid prototype printing using a single tissue equivalent material. The adipose tissue regions in the sections are filled using an epoxy-based resin combined with phenolic microspheres. The phantom sections are then stacked. The phantom is provided with an extra section modified to include iodine-enhanced masses. We fabricated a prototype phantom corresponding to a 450 ml breast with 45% dense tissue deformed to represent a 5 cm compressed thickness. The rapid prototype and epoxy based resin phantom materials attenuate x rays similar to 50% glandular tissue and 100% adipose tissue, respectively. The iodinated masses are between 4.0 and 9.6 mm thick and contain 2.5 mg/ml and 5 mg/ml iodine. Digital mammography and digital breast tomosynthesis images of the phantom are qualitatively similar in appearance to clinical images. In summary, a method to fabricate a 3D physical anthropomorphic breast phantom has been developed with known ground truth in the form of a companion voxel phantom. This combined system of physical and computational phantoms allows for both qualitative and quantitative image quality assessment.

  20. Automatic generation of digital anthropomorphic phantoms from simulated MRI acquisitions

    Science.gov (United States)

    Lindsay, C.; Gennert, M. A.; KÓ§nik, A.; Dasari, P. K.; King, M. A.

    2013-03-01

    In SPECT imaging, motion from patient respiration and body motion can introduce image artifacts that may reduce the diagnostic quality of the images. Simulation studies using numerical phantoms with precisely known motion can help to develop and evaluate motion correction algorithms. Previous methods for evaluating motion correction algorithms used either manual or semi-automated segmentation of MRI studies to produce patient models in the form of XCAT Phantoms, from which one calculates the transformation and deformation between MRI study and patient model. Both manual and semi-automated methods of XCAT Phantom generation require expertise in human anatomy, with the semiautomated method requiring up to 30 minutes and the manual method requiring up to eight hours. Although faster than manual segmentation, the semi-automated method still requires a significant amount of time, is not replicable, and is subject to errors due to the difficulty of aligning and deforming anatomical shapes in 3D. We propose a new method for matching patient models to MRI that extends the previous semi-automated method by eliminating the manual non-rigid transformation. Our method requires no user supervision and therefore does not require expert knowledge of human anatomy to align the NURBs to anatomical structures in the MR image. Our contribution is employing the SIMRI MRI simulator to convert the XCAT NURBs to a voxel-based representation that is amenable to automatic non-rigid registration. Then registration is used to transform and deform the NURBs to match the anatomy in the MR image. We show that our automated method generates XCAT Phantoms more robustly and significantly faster than the previous semi-automated method.

  1. Comparison of various anthropomorphic phantom types for in vivo measurements by means of Monte Carlo simulations

    International Nuclear Information System (INIS)

    Three widely used anthropomorphic phantoms are analysed with regard to their suitability for the efficiency calibration of whole-body counters (WBCs): a Bottle Manikin Absorber (BOMAB) phantom consisting of water-filled plastic containers, a St Petersburg block phantom (Research Inst. of Sea Transport Hygiene, St Petersburg) made of polyethylene bricks and a mathematical Medical Internal Radiation Dose (MIRD) phantom, each of them representing a person weighing 70 kg. The analysis was performed by means of Monte Carlo simulations with the Monte Carlo N-Particle transport code using detailed mathematical models of the phantoms and the WBC at Forschungszentrum Juelich (FZJ). The simulated peak efficiencies for the BOMAB phantom and the MIRD phantom agree very well, but the results for the St Petersburg phantom are considerably higher. Therefore, WBCs similar to that at FZJ will probably underestimate the activity of incorporated radionuclides if they are calibrated by means of a St Petersburg phantom. Finally, the results from this work are compared with the conclusions from other studies dealing with block and BOMAB phantoms. (authors)

  2. A method to acquire CT organ dose map using OSL dosimeters and ATOM anthropomorphic phantoms

    OpenAIRE

    Zhang, Da; Li, Xinhua; Gao, Yiming; Xu, X. George; Liu, Bob

    2013-01-01

    Purpose: To present the design and procedure of an experimental method for acquiring densely sampled organ dose map for CT applications, based on optically stimulated luminescence (OSL) dosimeters “nanoDots” and standard ATOM anthropomorphic phantoms; and to provide the results of applying the method—a dose data set with good statistics for the comparison with Monte Carlo simulation result in the future.

  3. Interactive generation of digital anthropomorphic phantoms from XCAT shape priors

    Science.gov (United States)

    Lindsay, C.; Gennert, M. A.; Connolly, C. M.; Konik, A.; Dasari, P. K.; Segars, W. P.; King, M. A.

    2012-03-01

    In SPECT imaging, patient respiratory and body motion can cause artifacts that degrade image quality. Developing and evaluating motion correction algorithms are facilitated by simulation studies where a numerical phantom and its motion are precisely known, from which image data can be produced. Previous techniques to test motion correction methods generated XCAT phantoms modeled from MRI studies and motion tracking but required manually segmenting the major structures within the whole upper torso, which can take 8 hours to perform. Additionally, segmentation in two dimensional MRI slices and interpolating into three dimensional shapes can lead to appreciable interpolation artifacts as well as requiring expert knowledge of human anatomy in order to identify the regions to be segmented within each slice. We propose a new method that mitigates the long manual segmentation times for segmenting the upper torso. Our interactive method requires that a user provide only an approximate alignment of the base anatomical shapes from the XCAT model with an MRI data. Organ boundaries from aligned XCAT models are warped with displacement fields generated from registering a baseline MR image to MR images acquired during pre-determined motions, which amounts to automated segmentation each organ of interest. With our method we can show the quality of segmentation is equal that of expert manual segmentation does not require a user who is an expert in anatomy, and can be completed in minutes not hours. In some instances, due to interpolation artifacts, our method can generate higher quality models than manual segmentation.

  4. 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)

  5. 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

  6. Evaluation of an anthropomorphic male pelvic phantom for image-guided radiotherapy

    Directory of Open Access Journals (Sweden)

    B Schaly

    2009-07-01

    Full Text Available B Schaly1, V Varchena2, P Au3, G Pang3,41Grand River Regional Cancer Centre, Kitchener, ON, Canada; 2CIRS Inc., Norfolk, VA, USA; 3Odette Cancer Centre, Toronto, ON, Canada; 4Departments of Radiation Oncology and Medical Biophysics, University of Toronto, Toronto, ON, Canada Abstract: Soft-tissue imaging in the treatment room is one of the main challenges faced today in high precision radiotherapy. The objective of this work is to evaluate a new anthropomorphic male pelvic phantom (CIRS Inc., Norfolk, VA, USA that can be used in a radiotherapy department to assess the ability of an X-ray imaging system for imaging soft-tissue targets in the treatment room. To this end, we evaluated the tissue-equivalency of the phantom materials in terms of the linear attenuation and energy absorption coefficients. X-ray computed tomography (CT images of the phantom were also obtained and compared with that of patients. Our results demonstrated that the male pelvic phantom is a good representation of actual prostate cancer patients and can be a valuable tool for image-guided radiotherapy. Keywords: image-guided radiotherapy, X-ray imaging, anthropomorphic phantomPACS numbers: 87.56.Fc, 87.59.bd, 87.85.Lf

  7. Analysis of translational errors in frame-based and frameless cranial radiosurgery using an anthropomorphic phantom

    International Nuclear Information System (INIS)

    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)

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

    Science.gov (United States)

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

    2014-03-01

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

  9. Creation of 3D digital anthropomorphic phantoms which model actual patient non-rigid body motion as determined from MRI and position tracking studies of volunteers

    Science.gov (United States)

    Connolly, C. M.; Konik, A.; Dasari, P. K. R.; Segars, P.; Zheng, S.; Johnson, K. L.; Dey, J.; King, M. A.

    2011-03-01

    Patient motion can cause artifacts, which can lead to difficulty in interpretation. The purpose of this study is to create 3D digital anthropomorphic phantoms which model the location of the structures of the chest and upper abdomen of human volunteers undergoing a series of clinically relevant motions. The 3D anatomy is modeled using the XCAT phantom and based on MRI studies. The NURBS surfaces of the XCAT are interactively adapted to fit the MRI studies. A detailed XCAT phantom is first developed from an EKG triggered Navigator acquisition composed of sagittal slices with a 3 x 3 x 3 mm voxel dimension. Rigid body motion states are then acquired at breath-hold as sagittal slices partially covering the thorax, centered on the heart, with 9 mm gaps between them. For non-rigid body motion requiring greater sampling, modified Navigator sequences covering the entire thorax with 3 mm gaps between slices are obtained. The structures of the initial XCAT are then adapted to fit these different motion states. Simultaneous to MRI imaging the positions of multiple reflective markers on stretchy bands about the volunteer's chest and abdomen are optically tracked in 3D via stereo imaging. These phantoms with combined position tracking will be used to investigate both imaging-data-driven and motion-tracking strategies to estimate and correct for patient motion. Our initial application will be to cardiacperfusion SPECT imaging where the XCAT phantoms will be used to create patient activity and attenuation distributions for each volunteer with corresponding motion tracking data from the markers on the body-surface. Monte Carlo methods will then be used to simulate SPECT acquisitions, which will be used to evaluate various motion estimation and correction strategies.

  10. Use of MOSFET dosimeters to validate Monte Carlo radiation treatment calculation in an anthropomorphic phantom

    Science.gov (United States)

    Juste, Belén; Miró, R.; Abella, V.; Santos, A.; Verdú, Gumersindo

    2015-11-01

    Radiation therapy treatment planning based on Monte Carlo simulation provide a very accurate dose calculation compared to deterministic systems. Nowadays, Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET) dosimeters are increasingly utilized in radiation therapy to verify the received dose by patients. In the present work, we have used the MCNP6 (Monte Carlo N-Particle transport code) to simulate the irradiation of an anthropomorphic phantom (RANDO) with a medical linear accelerator. The detailed model of the Elekta Precise multileaf collimator using a 6 MeV photon beam was designed and validated by means of different beam sizes and shapes in previous works. To include in the simulation the RANDO phantom geometry a set of Computer Tomography images of the phantom was obtained and formatted. The slices are input in PLUNC software, which performs the segmentation by defining anatomical structures and a Matlab algorithm writes the phantom information in MCNP6 input deck format. The simulation was verified and therefore the phantom model and irradiation was validated throughout the comparison of High-Sensitivity MOSFET dosimeter (Best medical Canada) measurements in different points inside the phantom with simulation results. On-line Wireless MOSFET provide dose estimation in the extremely thin sensitive volume, so a meticulous and accurate validation has been performed. The comparison show good agreement between the MOSFET measurements and the Monte Carlo calculations, confirming the validity of the developed procedure to include patients CT in simulations and approving the use of Monte Carlo simulations as an accurate therapy treatment plan.

  11. An anthropomorphic sonography phantom for the evaluation of mechatronic devices for heart surgery.

    Science.gov (United States)

    Korb, Werner; Fricke, Christopher; Jacobs, Stephan; Falk, Volkmar

    2015-12-01

    Surgical assistance systems are used to make surgical procedures more precise. The integration of automated intra-operative imaging in surgical interventions can be seen as an important step to further improve patient safety. An automatic soft tissue manipulation system with mechatronic assistance using endoscopic Doppler guidance was developed for minimally invasive coronary artery bypass surgery. To facilitate the complicated development process of the mechatronic system, we manufactured and validated an anthropomorphic phantom. A three-compartment model including soft tissue and a vessel system were manufactured for the phantom. Blood flow simulation was implemented using a pump and blood mimicking fluid in a closed circuit. Eighteen physicians evaluated the anatomical and physiological validity of the phantom in a study. The average rating of the anatomy, as well as the physiology, was good, although particular aspects of the phantom have shown a need for improvement. The validation study provided valuable information on limits and problems concerning the phantom and its applicability for the evaluation of the development steps of the mechatronic system. We showed how to develop and validate a phantom for the evaluation of a surgical assistance system with intraoperative imaging. The described concepts can be applied to similar developmental procedures and help generate a goal-driven and efficient development. PMID:25870954

  12. Novel anthropomorphic hip phantom corrects systemic interscanner differences in proximal femoral vBMD

    International Nuclear Information System (INIS)

    Quantitative computed tomography (QCT) is increasingly used in osteoporosis studies to assess volumetric bone mineral density (vBMD), bone quality and strength. However, QCT is confronted by technical issues in the clinical research setting, such as potentially confounding effects of body size on vBMD measurements and lack of standard approaches to scanner cross-calibration, which affects measurements of vBMD in multicenter settings. In this study, we addressed systematic inter-scanner differences and subject-dependent body size errors using a novel anthropomorphic hip phantom, containing a calibration hip to estimate correction equations, and a contralateral test hip to assess the quality of the correction. We scanned this phantom on four different scanners and we applied phantom-derived corrections to in vivo images of 16 postmenopausal women scanned on two scanners. From the phantom study, we found that vBMD decreased with increasing phantom size in three of four scanners and that inter-scanner variations increased with increasing phantom size. In the in vivo study, we observed that inter-scanner corrections reduced systematic inter-scanner mean vBMD differences but that the inter-scanner precision error was still larger than expected from known intra-scanner precision measurements. In conclusion, inter-scanner corrections and body size influence should be considered when measuring vBMD from QCT images. (paper)

  13. Evaluation of an anthropomorphic male pelvic phantom for image-guided radiotherapy

    OpenAIRE

    Pang, Geordi

    2009-01-01

    B Schaly1, V Varchena2, P Au3, G Pang3,41Grand River Regional Cancer Centre, Kitchener, ON, Canada; 2CIRS Inc., Norfolk, VA, USA; 3Odette Cancer Centre, Toronto, ON, Canada; 4Departments of Radiation Oncology and Medical Biophysics, University of Toronto, Toronto, ON, Canada Abstract: Soft-tissue imaging in the treatment room is one of the main challenges faced today in high precision radiotherapy. The objective of this work is to evaluate a new anthropomorphic male pelvic phantom (C...

  14. Characterization of MOSFET dosimeters for low-dose measurements in maxillofacial anthropomorphic phantoms.

    Science.gov (United States)

    Koivisto, Juha H; Wolff, Jan E; Kiljunen, Timo; Schulze, Dirk; Kortesniemi, Mika

    2015-01-01

    The aims of this study were to characterize reinforced metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters to assess the measurement uncertainty, single exposure low-dose limit with acceptable accuracy, and the number of exposures required to attain the corresponding limit of the thermoluminescent dosimeters (TLD). The second aim was to characterize MOSFET dosimeter sensitivities for two dental photon energy ranges, dose dependency, dose rate dependency, and accumulated dose dependency. A further aim was to compare the performance of MOSFETs with those of TLDs in an anthropomorphic phantom head using a dentomaxillofacial CBCT device. The uncertainty was assessed by exposing 20 MOSFETs and a Barracuda MPD reference dosimeter. The MOSFET dosimeter sensitivities were evaluated for two photon energy ranges (50-90 kVp) using a constant dose and polymethylmethacrylate backscatter material. MOSFET and TLD comparative point-dose measurements were performed on an anthropomorphic phantom that was exposed with a clinical CBCT protocol. The MOSFET single exposure low dose limit (25% uncertainty, k = 2) was 1.69 mGy. An averaging of eight MOSFET exposures was required to attain the corresponding TLD (0.3 mGy) low-dose limit. The sensitivity was 3.09 ± 0.13 mV/mGy independently of the photon energy used. The MOSFET dosimeters did not present dose or dose rate sensitivity but, however, presented a 1% decrease of sensitivity per 1000 mV for accumulated threshold voltages between 8300 mV and 17500 mV. The point doses in an anthropomorphic phantom ranged for MOSFETs between 0.24 mGy and 2.29 mGy and for TLDs between 0.25 and 2.09 mGy, respectively. The mean difference was -8%. The MOSFET dosimeters presented statistically insignificant energy dependency. By averaging multiple exposures, the MOSFET dosimeters can achieve a TLD-comparable low-dose limit and constitute a feasible method for diagnostic dosimetry using anthropomorphic phantoms. However, for single in

  15. Development of anthropomorphic hand phantoms for personal dosimetry in 90Y-zevalin preparation and patient delivering

    International Nuclear Information System (INIS)

    Anthropomorphic tissue-equivalent hand phantoms were achieved to measure the extremity dose involved in Zevalin 90Y-labelling and patient delivering procedure for radioimmunotherapy treatment of non-Hodgkin lymphoma. The extremity doses to hands and wrists of operators were measured by using thermoluminescent detectors mounted on the developed phantoms. Measurements of chest- and lens-equivalent doses performed on a Rando phantom are also reported. (authors)

  16. Development of anthropomorphic hand phantoms for personal dosimetry in 90Y-Zevalin preparation and patient delivering.

    Science.gov (United States)

    Ciolini, R; d'Errico, F; Traino, A C; Paternostro, E; Laganà, A; Romei, C; Pazzagli, F; Del Gratta, A

    2014-01-01

    Anthropomorphic tissue-equivalent hand phantoms were achieved to measure the extremity dose involved in Zevalin (90)Y-labelling and patient delivering procedure for radioimmunotherapy treatment of non-Hodgkin lymphoma. The extremity doses to hands and wrists of operators were measured by using thermoluminescent detectors mounted on the developed phantoms. Measurements of chest- and lens-equivalent doses performed on a Rando phantom are also reported. PMID:23960242

  17. A computer-controlled pump and realistic anthropomorphic respiratory phantom for validating image-guided systems

    Science.gov (United States)

    Lin, Ralph; Wilson, Emmanuel; Tang, Jonathan; Stoianovici, Dan; Cleary, Kevin

    2007-03-01

    The development of image-guided interventions requires validation studies to evaluate new protocols. So far, these validation studies have been limited to animal models and to software and physical phantoms that simulate respiratory motion but cannot accommodate needle punctures in a realistic manner. We have built a computer-controlled pump that drives an anthropomorphic respiratory phantom for simulating natural breathing patterns. This pump consists of a power supply, a motion controller with servo amplifier, linear actuator, and custom fabricated pump assembly. By generating several sample waveforms, we were able to simulate typical breathing patterns. Using this pump, we were able to produce chest wall movements similar to typical chest wall movements observed in humans. This system has potential applications for evaluating new respiratory compensation algorithms and may facilitate improved testing of image-guided protocols under realistic interventional conditions.

  18. Verification of lung dose in an anthropomorphic phantom calculated by the collapsed cone convolution method

    International Nuclear Information System (INIS)

    Verification of calculated lung dose in an anthropomorphic phantom is performed using two dosimetry media. Dosimetry is complicated by factors such as variations in density at slice interfaces and appropriate position on CT scanning slice to accommodate these factors. Dose in lung for a 6 MV and 10 MV anterior-posterior field was calculated with a collapsed cone convolution method using an ADAC Pinnacle, 3D planning system. Up to 5% variations between doses calculated at the centre and near the edge of the 2 cm phantom slice positioned at the beam central axis were seen, due to the composition of each phantom slice. Validation of dose was performed with LiF thermoluminescent dosimeters (TLDs) and X-Omat V radiographic film. Both dosimetry media produced dose results which agreed closely with calculated results nearest their physical positioning in the phantom. The collapsed cone convolution method accurately calculates dose within inhomogeneous lung regions at 6 MV and 10 MV x-ray energy. (author)

  19. Computational voxel phantom, associated to anthropometric and anthropomorphic real phantom for dosimetry in human male pelvis radiotherapy

    International Nuclear Information System (INIS)

    This paper addresses a computational model of voxels through MCNP5 Code and the experimental development of an anthropometric and anthropomorphic phantom for dosimetry in human male pelvis brachytherapy focusing prostatic tumors. For elaboration of the computational model of the human male pelvis, anatomical section images from the Visible Man Project were applied. Such selected and digital images were associated to a numeric representation, one for each section. Such computational representation of the anatomical sections was transformed into a bi-dimensional mesh of equivalent tissue. The group of bidimensional meshes was concatenated forming the three-dimensional model of voxels to be used by the MCNP5 code. In association to the anatomical information, data from the density and chemical composition of the basic elements, representatives of the organs and involved tissues, were setup in a material database for the MCNP-5. The model will be applied for dosimetric evaluations in situations of irradiation of the human masculine pelvis. Such 3D model of voxel is associated to the code of transport of particles MCNP5, allowing future simulations. It was also developed the construction of human masculine pelvis phantom, based on anthropometric and anthropomorphic dates and in the use of representative equivalent tissues of the skin, fatty, muscular and glandular tissue, as well as the bony structure.This part of work was developed in stages, being built the bony cast first, later the muscular structures and internal organs. They were then jointly mounted and inserted in the skin cast. The representative component of the fatty tissue was incorporate and accomplished the final retouchings in the skin. The final result represents the development of two important essential tools for elaboration of computational and experimental dosimetry. Thus, it is possible its use in calibrations of pre-existent protocols in radiotherapy, as well as for tests of new protocols, besides

  20. Calibration of a total body potassium monitor with an anthropomorphic phantom

    Science.gov (United States)

    Hansen, R. D.; Allen, B. J.

    1996-11-01

    An anthropomorphic phantom was used to calibrate a supine geometry sodium iodide total body potassium monitor. Correction factors accommodating variability in subject size were empirically determined. Measurements on 12 males of weight 45 - 96 kg, height 161 - 184 cm and 18 females of weight 48 - 89 kg, height 153 - 175 cm, showed that the calibration factor was significantly correlated (r = 0.88, p , indicating comparable accuracy to -based calibration procedures. Fat-free mass determined from the potassium measurements of 16 subjects correlated significantly with fat-free mass estimated from skinfold thickness (r = 0.98, p bioimpedance analysis (r = 0.98, p -based methods of calibrating total body potassium monitors.

  1. Calibration of a total body potassium monitor with an anthropomorphic phantom

    International Nuclear Information System (INIS)

    An anthropomorphic phantom was used to calibrate a supine geometry sodium iodide total body potassium monitor. Correction factors accommodating variability in subject size were empirically determined. Measurements on 12 males of weight 45-96 kg, height 161-184 cm and 18 females of weight 48-89 kg, height 153-175 cm, showed that the 40K calibration factor (F,countss-1(gofpotassium)-1 was significantly correlated (r=0.88, p0.5, indicating comparable accuracy to 42K-based calibration procedures. Fat-free mass determined from the potassium measurements of 16 subjects correlated significantly with fat-free mass estimated from skinfold thickness (r=0.98, p42K-based methods of calibrating total body potassium monitors. (author)

  2. Calibration of a total body potassium monitor with an anthropomorphic phantom.

    Science.gov (United States)

    Hansen, R D; Allen, B J

    1996-11-01

    An anthropomorphic phantom was used to calibrate a supine geometry sodium iodide total body potassium monitor. Correction factors accommodating variability in subject size were empirically determined. Measurements on 12 males of weight 45-96 kg, height 161-184 cm and 18 females of weight 48-89 kg, height 153-175 cm, showed that the 40K calibration factor (F, counts s-1 (g of potassium)-1) was significantly correlated (r = 0.88, p bioimpedance analysis (r = 0.98, p < 0.0001). These data, together with the precision (coefficient of variation, CV = 1.5%) and accuracy (CV = 4.5%) of the system, indicate that this calibration procedure represents a relatively low-cost, non-invasive alternative to 42K-based methods of calibrating total body potassium monitors. PMID:8938038

  3. Design and manufacturing of anthropomorphic thyroid-neck phantom for use in nuclear medicine centres in Chile.

    Science.gov (United States)

    Hermosilla, A; Díaz Londoño, G; García, M; Ruíz, F; Andrade, P; Pérez, A

    2014-12-01

    Anthropomorphic phantoms are used in nuclear medicine for imaging quality control, calibration of gamma spectrometry system for the study of internal contamination with radionuclides and for internal dosimetric studies. These are constructed of materials that have radiation attenuation coefficients similar to those of the different organs and tissues of the human body. The material usually used for the manufacture of phantoms is polymethyl methacrylate. Other materials used for this purpose are polyethylene, polystyrene and epoxy resin. This project presents the design and manufacture of an anthropomorphic thyroid-neck phantom that includes the cervical spine, trachea and oesophagus, using a polyester resin (ρ = 1.1 g cm(-3)). Its linear and mass attenuation coefficients were experimentally determined and simulated by means of XCOM software, finding that this material reproduces the soft tissue ICRU-44 in a range of energies between 80 keV and 11 MeV, with less than a 5 % difference. PMID:24567500

  4. Evaluation of the usefulness of a MOSFET detector in an anthropomorphic phantom for 6-MV photon beam.

    Science.gov (United States)

    Kohno, Ryosuke; Hirano, Eriko; Kitou, Satoshi; Goka, Tomonori; Matsubara, Kana; Kameoka, Satoru; Matsuura, Taeko; Ariji, Takaki; Nishio, Teiji; Kawashima, Mitsuhiko; Ogino, Takashi

    2010-07-01

    In order to evaluate the usefulness of a metal oxide-silicon field-effect transistor (MOSFET) detector as a in vivo dosimeter, we performed in vivo dosimetry using the MOSFET detector with an anthropomorphic phantom. We used the RANDO phantom as an anthropomorphic phantom, and dose measurements were carried out in the abdominal, thoracic, and head and neck regions for simple square field sizes of 10 x 10, 5 x 5, and 3 x 3 cm(2) with a 6-MV photon beam. The dose measured by the MOSFET detector was verified by the dose calculations of the superposition (SP) algorithm in the XiO radiotherapy treatment-planning system. In most cases, the measured doses agreed with the results of the SP algorithm within +/-3%. Our results demonstrated the utility of the MOSFET detector for in vivo dosimetry even in the presence of clinical tissue inhomogeneities. PMID:20821083

  5. SU-E-I-94: Automated Image Quality Assessment of Radiographic Systems Using An Anthropomorphic Phantom

    International Nuclear Information System (INIS)

    Purpose: In a large, academic medical center, consistent radiographic imaging performance is difficult to routinely monitor and maintain, especially for a fleet consisting of multiple vendors, models, software versions, and numerous imaging protocols. Thus, an automated image quality control methodology has been implemented using routine image quality assessment with a physical, stylized anthropomorphic chest phantom. Methods: The “Duke” Phantom (Digital Phantom 07-646, Supertech, Elkhart, IN) was imaged twice on each of 13 radiographic units from a variety of vendors at 13 primary care clinics. The first acquisition used the clinical PA chest protocol to acquire the post-processed “FOR PRESENTATION” image. The second image was acquired without an antiscatter grid followed by collection of the “FOR PROCESSING” image. Manual CNR measurements were made from the largest and thickest contrast-detail inserts in the lung, heart, and abdominal regions of the phantom in each image. An automated image registration algorithm was used to estimate the CNR of the same insert using similar ROIs. Automated measurements were then compared to the manual measurements. Results: Automatic and manual CNR measurements obtained from “FOR PRESENTATION” images had average percent differences of 0.42%±5.18%, −3.44%±4.85%, and 1.04%±3.15% in the lung, heart, and abdominal regions, respectively; measurements obtained from “FOR PROCESSING” images had average percent differences of -0.63%±6.66%, −0.97%±3.92%, and −0.53%±4.18%, respectively. The maximum absolute difference in CNR was 15.78%, 10.89%, and 8.73% in the respective regions. In addition to CNR assessment of the largest and thickest contrast-detail inserts, the automated method also provided CNR estimates for all 75 contrast-detail inserts in each phantom image. Conclusion: Automated analysis of a radiographic phantom has been shown to be a fast, robust, and objective means for assessing radiographic

  6. SU-E-I-94: Automated Image Quality Assessment of Radiographic Systems Using An Anthropomorphic Phantom

    Energy Technology Data Exchange (ETDEWEB)

    Wells, J; Wilson, J; Zhang, Y; Samei, E; Ravin, Carl E. [Advanced Imaging Laboratories, Duke Clinical Imaging Physics Group, Department of Radiology, Duke University Medical Center, Durham, NC (United States)

    2014-06-01

    Purpose: In a large, academic medical center, consistent radiographic imaging performance is difficult to routinely monitor and maintain, especially for a fleet consisting of multiple vendors, models, software versions, and numerous imaging protocols. Thus, an automated image quality control methodology has been implemented using routine image quality assessment with a physical, stylized anthropomorphic chest phantom. Methods: The “Duke” Phantom (Digital Phantom 07-646, Supertech, Elkhart, IN) was imaged twice on each of 13 radiographic units from a variety of vendors at 13 primary care clinics. The first acquisition used the clinical PA chest protocol to acquire the post-processed “FOR PRESENTATION” image. The second image was acquired without an antiscatter grid followed by collection of the “FOR PROCESSING” image. Manual CNR measurements were made from the largest and thickest contrast-detail inserts in the lung, heart, and abdominal regions of the phantom in each image. An automated image registration algorithm was used to estimate the CNR of the same insert using similar ROIs. Automated measurements were then compared to the manual measurements. Results: Automatic and manual CNR measurements obtained from “FOR PRESENTATION” images had average percent differences of 0.42%±5.18%, −3.44%±4.85%, and 1.04%±3.15% in the lung, heart, and abdominal regions, respectively; measurements obtained from “FOR PROCESSING” images had average percent differences of -0.63%±6.66%, −0.97%±3.92%, and −0.53%±4.18%, respectively. The maximum absolute difference in CNR was 15.78%, 10.89%, and 8.73% in the respective regions. In addition to CNR assessment of the largest and thickest contrast-detail inserts, the automated method also provided CNR estimates for all 75 contrast-detail inserts in each phantom image. Conclusion: Automated analysis of a radiographic phantom has been shown to be a fast, robust, and objective means for assessing radiographic

  7. Use of an Anthropomorphic Phantom to Improve the External Beam Quality Audits in Radiotherapy

    International Nuclear Information System (INIS)

    The present paper describes the Cuban experience in the implementation of an external quality audit system for high energy radiotherapy photon beams (60Co and linac) in non-reference conditions using a thorax (CIRS) phantom. By comparing the calculated and actually delivered doses for four test cases, it is possible to check the quality of the entire planning chain from prescription to delivery as well as the integrity of the beam data modelled into the treatment planning system (TPS). The test cases were taken/modified from IAEA TRS 430 and include direct, tangential, wedged, blocked and multiple fields, all commonly used in clinic. According to the available insertion holes in the phantom, a number of dose points were defined and calculated with four different clinical TPSs used in our environment. Subsequently the dose was measured at these points with an ionization chamber. A set of audit results with on-site measurement are shown to demonstrate the practicability of the method. The points were classified by regions according to their position with respect to the beam axis. The 90% of measured points were found within tolerance. For the failing 10% we found no correlation with TPS (centre) or with the complexity of the case. For all test cases, except the simplest one, at least one department/TPS prediction falls outside tolerance. There is no significant difference among the audited departments. (author)

  8. An anthropomorphic head and neck phantom for evaluation of intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Intensity Modulated Radiation Therapy (IMRT) has gained acceptance as an improved treatment technique for several disease sites. As the use of IMRT increases, national cancer study groups are beginning to initiate clinical trials that involve its use. Because IMRT offers the possibility of high dose gradients, it is possible to deliver high doses to target volumes while maintaining low doses to nearby critical normal structures. The use of high gradients means that localization of the dose distribution is critical. Small errors in positioning of the patient can cause a target volume to be missed or a critical structure to receive a higher dose than can be tolerated. Consequently, it is important that the institutions participating in clinical trials administer IMRT consistently and accurately. The Radiological Physics Center (RPC) has been funded by the US National Cancer Institute (NCI) to assure the study groups that participants in clinical trials have adequate QA procedures and that their patient dosimetry is accurate. The RPC also reviews and credentials institutions to participate in some high-technology clinical trials. To credential institutions for IMRT head and neck trials, the RPC has developed a mailable anthropomorphic head and neck phantom. The phantom has been used to evaluate the imaging, planning and delivery of IMRT prior to the institution's participation in the protocol. The water-filled phantom contains a polystyrene insert that incorporates solid-water imageable structures representing a primary planning target volume (PTV), a secondary PTV and a critical structure. The insert holds four TLD as well as a set of orthogonal radiochromic films. TLD results combined with profiles taken from the film were used to demonstrate that doses were delivered accurately to the intended locations

  9. An anthropomorphic phantom for quality assurance and training in gynaecological brachytherapy

    International Nuclear Information System (INIS)

    Background and purpose: An anthropomorphic water filled polymethylmethacrylate (PMMA) phantom designed to serve as a Quality Assurance (QA) tool and a training aid in brachytherapy of gynaecological tumours is investigated and presented. Several dosimetric parameters associated with the dose rate calculation can be verified with the aid of this phantom such as the source positioning, its imaging reconstruction from radiographs and the accuracy of the algorithm used for manual or computer dose rate calculation. Material and methods: The phantom walls and the internal structure are 5 mm thick and consist of PMMA, in the form of the abdomen taken from a female Alderson Phantom Marker points representing the organs of interest were determined from computed tomography scans of a patient of similar size. Three PMMA inserts designed to hold a Farmer type ionization chamber of 0.6 cm3 were positioned at the points to represent the bladder, rectum and point A. The formalism proposed by the IAEA TRS-277 dosimetry protocol was used for the conversion of readings of the ionization chamber to dose rate values with a modification to take into account the dose rate gradient in the detector. Five 137Cs sources were used and the dose rate was evaluated by measurements and Monte Carlo simulations using the PENELOPE code. Four different treatment planning systems with different algorithms and source reconstruction techniques were also used in this investigation and compared with the manual dose rate calculations made using Karen and Breitman's tables. Results: The dose rate calculations performed with Monte Carlo and the four treatment planning systems are in good agreement with the experimental results as well as with the manual calculations when the colpostat shielding and the tandem attenuation are taken into account. The comparison between experiment and calculations by the four treatment planning systems shows a maximum variation of 5.1% between the calculated and measured dose

  10. Dose imaging in a thorax phantom with lung-equivalent volume at the epithermal neutron beam of LVR-15 reactor

    Energy Technology Data Exchange (ETDEWEB)

    Gambarini, G. [Department of Physics, University of Milan (Italy); INFN-National Institute of Nuclear Physics, Division of Milan (Italy)], E-mail: grazia.gambarini@mi.infn.it; Vanossi, E. [Department of Energy, Polytechnic of Milan (Italy); INFN-National Institute of Nuclear Physics, Division of Milan (Italy); Bartesaghi, G. [Department of Physics, University of Milan (Italy); INFN-National Institute of Nuclear Physics, Division of Milan (Italy); Carrara, M. [Fondazione IRCCS ' Istituto Nazionale Tumori' , Milan (Italy); Mariani, M. [Department of Energy, Polytechnic of Milan (Italy); Negri, A. [Department of Physics, University of Milan (Italy); INFN-National Institute of Nuclear Physics, Division of Milan (Italy); Burian, J.; Viererbl, L.; Klupak, V.; Rejchrt, J. [Department of Reactor Physics, NRI Rez, plc (Czech Republic)

    2009-07-15

    A thorax phantom has been designed, consisting of PMMA and PE plates containing a cavity filled with a laboratory-made lung-substitute. Fricke-gel dosimeters have been placed in the lung-substitute volume, and the phantom has been irradiated at the epithermal column of LVR-15 reactor. Absorbed dose images have been obtained for both gamma radiation and charged particles emitted in the {sup 10}B reactions with thermal neutrons. Measurements with thermoluminescence dosimeters (TLDs) and Monte Carlo (MC) calculations have been performed too, in order to attain inter-comparison of results.

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

    International Nuclear Information System (INIS)

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

  12. Dosimetric intercomparison for two Australasian clinical trials using an anthropomorphic phantom

    International Nuclear Information System (INIS)

    Introduction: Many different factors can affect the accurate delivery of dose to the clinical target volume in radiotherapy. This is particularly important in the context of multicenter clinical trials where different equipment and techniques may be used for supposedly identical treatments. A dosimetric intercomparison employing an anthropomorphic phantom (level III dosimetric intercomparison) can be used to check many of the factors that could affect treatment by mimicking the radiotherapy pathway of a patient as closely as possible. Methods and Materials: An anthropomorphic phantom (ART) was taken to 18 radiotherapy centers in Australia and New Zealand and treated for two different treatment scenarios based on current clinical trials of the Trans-Tasman Radiation Oncology Group (TROG): a two-field treatment of a carcinoma of the tonsil (TROG 91.01), and a four-field prostate treatment (TROG 96.01). The dose distribution was assessed in two consecutive treatments using thermoluminescence dosimeters (TLDs) placed throughout the target volume and in 'critical' structures such as the lens of the eye or the rectum. The study also included a check of absolute dose calibration in a slab phantom (level I dosimetric intercomparison). The influence of a variety of treatment parameters on the dose homogeneity in the target and the measured dose in the target and the critical organs was evaluated. Results: The dose measurements confirmed that in all participating centers the correct dose was delivered to the ICRU reference point (tonsil: 99.8±2.3%; prostate: 100.9±1.9% [1 SD]). Also the absolute dose calibration and the mean dose in the target volume were within the specified action levels of ±5% for all participating centers. No influence of shielding, beam modifiers, beam weighting, treatment planning approach (CT, 2D, 3D), and type of equipment used on the dose in the target and its homogeneity could be demonstrated. However, treatment technique and energy used

  13. Medical staff extremity dosimetry in CT fluoroscopy: an anthropomorphic hand voxel phantom study

    Science.gov (United States)

    Figueira, C.; Becker, F.; Blunck, C.; DiMaria, S.; Baptista, M.; Esteves, B.; Paulo, G.; Santos, J.; Teles, P.; Vaz, P.

    2013-08-01

    This work aims to contribute to the study of the radiation dose distribution delivered to the hands of medical staff members during a general computed tomographic (CT) fluoroscopic guided procedure. In this study, both Monte Carlo simulations and measurements were performed. For free-in-air and computed tomography dose index (CTDI) body phantom measurements, a standard pencil ionization chamber (IC) 100 mm long was used. The CT scanner model was implemented using MCNPX (Monte Carlo N-Particle eXtended) and was successfully validated by comparing the simulated results with measurements. Subsequently, CT images of a hand, together with an anthropomorphic phantom, were voxelized and used with the MCNPX code for dose calculations. The hand dose distribution study was performed both by using thermo-luminescent detector measurements and Monte Carlo simulations. The validated simulation tool provides a new perspective for detailed investigations of CT-irradiation scenarios. Simulations show that there is a strong dose gradient, namely the even zones of the hand that are in precise vicinity to the x-ray beam only receive about 4% of the maximum dose delivered to adjacent areas which are directly exposed to the primary x-ray beam. Finally, the scatter contribution of the patient was also studied through MC simulations. The results show that for directly exposed parts of the hand surface, the dose is reduced by the body of the patient (due to the shielding), whereas the dose is increased by scattered radiation from the patient for parts of the skin that receive scattered radiation only.

  14. Evaluation of iterative reconstruction method and attenuation correction on brain dopamine transporter SPECT using anthropomorphic striatal phantom

    OpenAIRE

    Akira Maebatake; Ayaka Imamura; Yui Kodera; Yasuo Yamashita; Kazuhiko Himuro; Shingo Baba; Kenta Miwa; Masayuki Sasaki

    2016-01-01

    Objective(s): The aim of this study was to determine the optimal reconstruction parameters for iterative reconstruction in different devices and collimators for dopamine transporter (DaT) single-photon emission computed tomography (SPECT). The results were compared between filtered back projection (FBP) and different attenuation correction (AC) methods.Methods: An anthropomorphic striatal phantom was filled with 123I solutions at different striatum-to-background radioactivity ratios. Data wer...

  15. Exposures in interventional radiology using Monte Carlo simulation coupled with virtual anthropomorphic phantoms.

    Science.gov (United States)

    Santos, William S; Neves, Lucio P; Perini, Ana P; Belinato, Walmir; Caldas, Linda V E; Carvalho, Albérico B; Maia, Ana F

    2015-12-01

    In this work we investigated the way in which conversion coefficients from air kerma-area product for effective doses (CCE) and entrance skin doses (CCESD) in interventional radiology (IR) are affected by variations in the filtration, projection angle of the X-ray beam, lead curtain attached to the surgical table, and suspended shield lead glass in regular conditions of medical practice. Computer simulations were used to model an exposure scenario similar to a real IR room. The patient and the physician were represented by MASH virtual anthropomorphic phantoms, inserted in the MCNPX 2.7.0 radiation transport code. In all cases, the addition of copper filtration also increased the CCE and CCESD values. The highest CCE values were obtained for lateral, cranial and caudal projections. In these projections, the X-ray tube was located above the table, and more scattered radiation reached the middle and upper portions of the physician trunk, where most of the radiosensitive organs are located. Another important result of this study was to show that the physician's protection is 358% higher when the lead curtain and suspended shield lead glasses are used. The values of CCE and CCESD, presented in this study, are an important resource for calculation of effective doses and entrance skin doses in clinical practice. PMID:26160701

  16. Optimising radiographic bitewing examination to adult and juvenile patients through the use of anthropomorphic phantoms

    International Nuclear Information System (INIS)

    Four anthropomorphic phantoms (an adult male, an adult female, a 10-y-old child and a 5-y-old child) were exposed to bitewing radiographs at film and digital settings using both rectangular and round collimation. Optically stimulated dosemeters were used. For children, average organ doses were <40 μGy and the organs with the highest doses were the salivary glands, parotid, oral mucosa, skin and extrathoracic airway. For adults, average organ doses were <200 μGy. Highest adult doses were to the salivary glands, oral mucosa and skin. Effective doses ranged from 1.5 to 1.8 μSv for children and from 2.6 to 3.6 μSv for adults when optimised technique factors were employed, including digital receptors, rectangular collimation, size-appropriate exposure times and proper clinical judgment. Optimised doses were a fraction of the natural daily background exposure. Therefore, predictions of hypothetical cancer incidence or detriment in patient populations exposed to such low doses are highly speculative and should be discouraged. (authors)

  17. Dose evaluation in occupationally exposed workers through dosimeters ring and wrist type with an anthropomorphic phantom

    International Nuclear Information System (INIS)

    In the Nuclear Medicine service of the Clinica San Pablo (Peru), the occupationally exposed workers carried out the preparation and administration of radiopharmaceuticals to patients, so it is vital to measure the equivalent dose to the hands during the procedures in order to optimize the exposure to the ionizing radiation and execute the Radiological Safety Regulation (D.S. No. 009-97-Em) and the standard IR 002.2012 of radiation protection and safety in nuclear medicine. In this paper was designed and built a hand anthropomorphic phantom made of paraffin following the description given for the standard man, later were placed dosimeters ring and wrist type UD-807 model, Panasonic brand. Then we proceeded to irradiate using vial containers of Tc-99 and I-131. The obtained results showed the difference between the equivalent dose obtained among the ring and wrist dosimeter also getting a dose of 153 mSv /year when working with 99mTc and of 61 mSv /year when working with iodine-131. Was also demonstrated that the ring dosimeter shows the average dose received in the hand with less dispersion. It was found that under the national regulation on Requirements of Radiation Protection and Nuclear Safety in Medicine article 63, indicates that higher doses of 150 mSv /year the occupationally exposed workers should have hand dosimetry. Finally the individual dose limit of 500 mSv /year in extremities can be overcome if adequate radiation protection standards do not apply. (author)

  18. In vivo proton dosimetry using a MOSFET detector in an anthropomorphic phantom with tissue inhomogeneity.

    Science.gov (United States)

    Kohno, Ryosuke; Hotta, Kenji; Matsubara, Kana; Nishioka, Shie; Matsuura, Taeko; Kawashima, Mitsuhiko

    2012-01-01

    When in vivo proton dosimetry is performed with a metal-oxide semiconductor field-effect transistor (MOSFET) detector, the response of the detector depends strongly on the linear energy transfer. The present study reports a practical method to correct the MOSFET response for linear energy transfer dependence by using a simplified Monte Carlo dose calculation method (SMC). A depth-output curve for a mono-energetic proton beam in polyethylene was measured with the MOSFET detector. This curve was used to calculate MOSFET output distributions with the SMC (SMC(MOSFET)). The SMC(MOSFET) output value at an arbitrary point was compared with the value obtained by the conventional SMC(PPIC), which calculates proton dose distributions by using the depth-dose curve determined by a parallel-plate ionization chamber (PPIC). The ratio of the two values was used to calculate the correction factor of the MOSFET response at an arbitrary point. The dose obtained by the MOSFET detector was determined from the product of the correction factor and the MOSFET raw dose. When in vivo proton dosimetry was performed with the MOSFET detector in an anthropomorphic phantom, the corrected MOSFET doses agreed with the SMC(PPIC) results within the measurement error. To our knowledge, this is the first report of successful in vivo proton dosimetry with a MOSFET detector. PMID:22402385

  19. Intensity modulated irradiation of a thorax phantom: comparisons between measurements, Monte Carlo calculations and pencil beam calculations

    Science.gov (United States)

    Laub, Wolfram U.; Bakai, Annemarie; Nüsslin, Fridtjof

    2001-06-01

    The present study investigates the application of compensators for the intensity modulated irradiation of a thorax phantom. Measurements are compared with Monte Carlo and standard pencil beam algorithm dose calculations. Compensators were manufactured to produce the intensity profiles that were generated from the scientific version of the KonRad IMRT treatment-planning system for a given treatment plan. The comparison of dose distributions calculated with a pencil beam algorithm, with the Monte Carlo code EGS4 and with measurements is presented. By measurements in a water phantom it is demonstrated that the method used to manufacture the compensators reproduces the intensity profiles in a suitable manner. Monte Carlo simulations in a water phantom show that the accelerator head model used for simulations is sufficient. No significant overestimations of dose values inside the target volume by the pencil beam algorithm are found in the thorax phantom. An overestimation of dose values in lung by the pencil beam algorithm is also not found. Expected dose calculation errors of the pencil beam algorithm are suppressed, because the dose to the low density region lung is reduced by the use of a non-coplanar beam arrangement and by intensity modulation.

  20. On the need to revise the arm structure in stylized anthropomorphic phantoms in lateral photon irradiation geometry

    International Nuclear Information System (INIS)

    Distributions of radiation absorbed dose within human anatomy have been estimated through Monte Carlo radiation transport techniques implemented for two different classes of computational anthropomorphic phantoms: (1) mathematical equation-based stylized phantoms and (2) tomographic image-based voxel phantoms. Voxel phantoms constructed from tomographic images of real human anatomy have been actively developed since the late 1980s to overcome the anatomical approximations necessary with stylized phantoms, which themselves have been utilized since the mid 1960s. However, revisions of stylized phantoms have also been pursued in parallel to the development of voxel phantoms since voxel phantoms (1) are initially restricted to the individual-specific anatomy of the person originally imaged, (2) must be restructured on an organ-by-organ basis to conform to reference individual anatomy and (3) cannot easily represent very fine anatomical structures and tissue layers that are thinner than the voxel dimensions of the overall phantom. Although efforts have been made to improve the anatomic realism of stylized phantoms, most of these efforts have been limited to attempts to alter internal organ structures. Aside from the internal organs, the exterior shapes, and especially the arm structures, of stylized phantoms are also far from realistic descriptions of human anatomy, and may cause dosimetry errors in the calculation of organ-absorbed doses for external irradiation scenarios. The present study was intended to highlight the need to revise the existing arm structure within stylized phantoms by comparing organ doses of stylized adult phantoms with those from three adult voxel phantoms in the lateral photon irradiation geometry. The representative stylized phantom, the adult phantom of the Oak Ridge National Laboratory (ORNL) series and two adult male voxel phantoms, KTMAN-2 and VOXTISS8, were employed for Monte Carlo dose calculation, and data from another voxel phantom, VIP

  1. Development and implementation of an anthropomorphic pediatric spine phantom for the assessment of craniospinal irradiation procedures in proton therapy

    Directory of Open Access Journals (Sweden)

    Dana J Lewis

    2014-03-01

    Full Text Available Purpose: To design an anthropomorphic pediatric spine phantom for use in the evaluation of proton therapy facilities for clinical trial participation by the Imaging and Radiation Oncology Core (IROC Houston QA Center (formerly RPC.Methods: This phantom was designed to perform an end-to-end audit of the proton spine treatment process, including simulation, dose calculation by the treatment planning system (TPS, and proton treatment delivery. The design incorporated materials simulating the thoracic spinal column of a pediatric patient, along with two thermoluminescent dosimeter (TLD-100 capsules and radiochromic film embedded in the phantom for dose evaluation. Fourteen potential materials were tested to determine relative proton stopping power (RSP and Hounsfield unit (HU values. Each material was CT scanned at 120 kVp, and the RSP was obtained from depth ionization scans using the Zebra multi-layer ion chamber (MLIC at two energies: 160 MeV and 250 MeV. To determine tissue equivalency, the measured RSP for each material was compared to the RSP calculated by the Eclipse TPS for a given HU.Results: The materials selected as bone, tissue, and cartilage substitutes were Techron HPV Bearing Grade (Boedeker Plastics, Inc., solid water, and blue water, respectively. The RSP values did not differ by more than 1.8% between the two energies. The measured RSP for each selected material agreed with the RSP calculated by the Eclipse TPS within 1.2%.Conclusion: An anthropomorphic pediatric proton spine phantom was designed to evaluate proton therapy delivery. The inclusion of multiple tissue substitutes increases heterogeneity and the level of difficulty for institutions to successfully treat the phantom. The following attributes will be evaluated: absolute dose agreement, distal range, field width, junction match and right/left dose profile alignment. The phantom will be tested at several institutions using a 5% dose agreement criterion, and a 5%/3mm gamma

  2. An anthropomorphic multimodality (CT/MRI) head phantom prototype for end-to-end tests in ion radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Gallas, Raya R.; Huenemohr, Nora; Runz, Armin; Niebuhr, Nina I.; Greilich, Steffen [German Cancer Research Center (DKFZ), Heidelberg (Germany). Div. of Medical Physics in Radiation Oncology; National Center for Radiation Research in Oncology, Heidelberg (Germany). Heidelberg Institute of Radiation Oncology (HIRO); Jaekel, Oliver [German Cancer Research Center (DKFZ), Heidelberg (Germany). Div. of Medical Physics in Radiation Oncology; National Center for Radiation Research in Oncology, Heidelberg (Germany). Heidelberg Institute of Radiation Oncology (HIRO); Heidelberg University Hospital (Germany). Dept. of Radiation Oncology; Heidelberg Ion-Beam Therapy Center (HIT), Heidelberg (Germany)

    2015-07-01

    With the increasing complexity of external beam therapy ''end-to-end'' tests are intended to cover every step from therapy planning through to follow-up in order to fulfill the higher demands on quality assurance. As magnetic resonance imaging (MRI) has become an important part of the treatment process, established phantoms such as the Alderson head cannot fully be used for those tests and novel phantoms have to be developed. Here, we present a feasibility study of a customizable multimodality head phantom. It is initially intended for ion radiotherapy but may also be used in photon therapy. As basis for the anthropomorphic head shape we have used a set of patient computed tomography (CT) images. The phantom recipient consisting of epoxy resin was produced by using a 3D printer. It includes a nasal air cavity, a cranial bone surrogate (based on dipotassium phosphate), a brain surrogate (based on agarose gel), and a surrogate for cerebrospinal fluid (based on distilled water). Furthermore, a volume filled with normoxic dosimetric gel mimicked a tumor. The entire workflow of a proton therapy could be successfully applied to the phantom. CT measurements revealed CT numbers agreeing with reference values for all surrogates in the range from 2 HU to 978 HU (120 kV). MRI showed the desired contrasts between the different phantom materials especially in T2-weighted images (except for the bone surrogate). T2-weighted readout of the polymerization gel dosimeter allowed approximate range verification.

  3. An anthropomorphic multimodality (CT/MRI) head phantom prototype for end-to-end tests in ion radiotherapy.

    Science.gov (United States)

    Gallas, Raya R; Hünemohr, Nora; Runz, Armin; Niebuhr, Nina I; Jäkel, Oliver; Greilich, Steffen

    2015-12-01

    With the increasing complexity of external beam therapy "end-to-end" tests are intended to cover every step from therapy planning through to follow-up in order to fulfill the higher demands on quality assurance. As magnetic resonance imaging (MRI) has become an important part of the treatment process, established phantoms such as the Alderson head cannot fully be used for those tests and novel phantoms have to be developed. Here, we present a feasibility study of a customizable multimodality head phantom. It is initially intended for ion radiotherapy but may also be used in photon therapy. As basis for the anthropomorphic head shape we have used a set of patient computed tomography (CT) images. The phantom recipient consisting of epoxy resin was produced by using a 3D printer. It includes a nasal air cavity, a cranial bone surrogate (based on dipotassium phosphate), a brain surrogate (based on agarose gel), and a surrogate for cerebrospinal fluid (based on distilled water). Furthermore, a volume filled with normoxic dosimetric gel mimicked a tumor. The entire workflow of a proton therapy could be successfully applied to the phantom. CT measurements revealed CT numbers agreeing with reference values for all surrogates in the range from 2 HU to 978 HU (120 kV). MRI showed the desired contrasts between the different phantom materials especially in T2-weighted images (except for the bone surrogate). T2-weighted readout of the polymerization gel dosimeter allowed approximate range verification. PMID:26189015

  4. An anthropomorphic multimodality (CT/MRI) head phantom prototype for end-to-end tests in ion radiotherapy

    International Nuclear Information System (INIS)

    With the increasing complexity of external beam therapy ''end-to-end'' tests are intended to cover every step from therapy planning through to follow-up in order to fulfill the higher demands on quality assurance. As magnetic resonance imaging (MRI) has become an important part of the treatment process, established phantoms such as the Alderson head cannot fully be used for those tests and novel phantoms have to be developed. Here, we present a feasibility study of a customizable multimodality head phantom. It is initially intended for ion radiotherapy but may also be used in photon therapy. As basis for the anthropomorphic head shape we have used a set of patient computed tomography (CT) images. The phantom recipient consisting of epoxy resin was produced by using a 3D printer. It includes a nasal air cavity, a cranial bone surrogate (based on dipotassium phosphate), a brain surrogate (based on agarose gel), and a surrogate for cerebrospinal fluid (based on distilled water). Furthermore, a volume filled with normoxic dosimetric gel mimicked a tumor. The entire workflow of a proton therapy could be successfully applied to the phantom. CT measurements revealed CT numbers agreeing with reference values for all surrogates in the range from 2 HU to 978 HU (120 kV). MRI showed the desired contrasts between the different phantom materials especially in T2-weighted images (except for the bone surrogate). T2-weighted readout of the polymerization gel dosimeter allowed approximate range verification.

  5. The measurement of organic radiation dose of multi-slice CT scanning by using the Chinese anthropomorphic chest phantom

    International Nuclear Information System (INIS)

    Objective: Using the Chinese anthropomorphic chest phantom to measure the absorbed dose of various tissues and organs under different noise index, and to assess the radiation dose of MSCT chest scanning with the effective dose (ED). Methods: The equivalence of the Chinese anthropomorphic chest phantom (CDP-1 C) and the adult chest on CT sectional anatomy and X-ray attenuation was demonstrated. The absorbed doses of various tissues and organs under different noise index were measured by laying thermoluminescent dosimeters (TLD) inside the phantom, and the corresponding dose-length products (DLP) were recorded. Both of them were later converted into ED and comparison was conducted to analyze the dose levels of chest CT scanning with automatic tube current modulation (ATCM) under different noise index. Student t-test was applied using SPSS 12.0 statistical software. Results: The Phantom was similar to the human body on CT sectional anatomy. The average CT value of phantom are - 788.04 HU in lung, 45.64 HU in heart, 65.84 HU in liver, 254.32 HU in spine and the deviations are 0.10%, 3.04%, 4.49% and 4.36% respectively compared to humans. The difference of average CT value of liver was statistically significant (t=-8.705, P0.05). As the noise index increased from 8.5 to 22.5, the DLP decreased from 393.57 mGy · cm to 78.75 mGy · cm and the organs dose declined. For example, the average absorbed dose decreased from 22.38 mGy to 3.66 mGy in lung. Compared to ED calculating by absorbed dose, the ED calculating by DLP was lower. The ED values of the two methods were 6.69 mSv and 8.77 mSv when the noise index was set at 8.5. Conclusions: Application of the Chinese anthropomorphic chest phantom to carry out CT dose assessment is more accurate. The noise index should be set more than 8.5 during the chest CT scanning based on ATCM technique. (authors)

  6. Pediatric radiation dosimetry for positron-emitting radionuclides using anthropomorphic phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Tianwu [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva 4 (Switzerland); Bolch, Wesley E. [Departments of Biomedical Engineering, University of Florida, Gainesville, Florida 32611 (United States); Lee, Choonsik [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institute of Health, Rockville, Maryland 20850 (United States); Zaidi, Habib [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva 4 (Switzerland); Geneva Neuroscience Center, Geneva University, CH-1205 Geneva (Switzerland); Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, 9700 RB Groningen (Netherlands)

    2013-10-15

    Purpose: Positron emission tomography (PET) plays an important role in the diagnosis, staging, treatment, and surveillance of clinically localized diseases. Combined PET/CT imaging exhibits significantly higher sensitivity, specificity, and accuracy than conventional imaging when it comes to detecting malignant tumors in children. However, the radiation dose from positron-emitting radionuclide to the pediatric population is a matter of concern since children are at a particularly high risk when exposed to ionizing radiation.Methods: The authors evaluate the absorbed fractions and specific absorbed fractions (SAFs) of monoenergy photons/electrons as well as S-values of 9 positron-emitting radionuclides (C-11, N-13, O-15, F-18, Cu-64, Ga-68, Rb-82, Y-86, and I-124) in 48 source regions for 10 anthropomorphic pediatric hybrid models, including the reference newborn, 1-, 5-, 10-, and 15-yr-old male and female models, using the Monte Carlo N-Particle eXtended general purpose Monte Carlo transport code.Results: The self-absorbed SAFs and S-values for most organs were inversely related to the age and body weight, whereas the cross-dose terms presented less correlation with body weight. For most source/target organ pairs, Rb-82 and Y-86 produce the highest self-absorbed and cross-absorbed S-values, respectively, while Cu-64 produces the lowest S-values because of the low-energy and high-frequency of electron emissions. Most of the total self-absorbed S-values are contributed from nonpenetrating particles (electrons and positrons), which have a linear relationship with body weight. The dependence of self-absorbed S-values of the two annihilation photons varies to the reciprocal of 0.76 power of the mass, whereas the self-absorbed S-values of positrons vary according to the reciprocal mass.Conclusions: The produced S-values for common positron-emitting radionuclides can be exploited for the assessment of radiation dose delivered to the pediatric population from various PET

  7. [CALCULATION OF RADIATION LOADS ON THE ANTHROPOMORPHIC PHANTOM ONBOARD THE SPACE STATION IN THE CASE OF ADDITIONAL SHIELDING].

    Science.gov (United States)

    Kartashov, D A; Shurshakov, V A

    2015-01-01

    The paper presents the results of calculating doses from space ionizing radiation for a modeled orbital station cabin outfitted with an additional shield aimed to reduce radiation loads on cosmonaut. The shield is a layer with the mass thickness of -6 g/cm2 (mean density = 0.62 g/cm3) that covers the outer cabin wall and consists of wet tissues and towels used by cosmonauts for hygienic purposes. A tissue-equivalent anthropomorphic phantom imitates human body. Doses were calculated for the standard orbit of the International space station (ISS) with consideration of the longitudinal and transverse phantom orientation relative to the wall with or without the additional shield. Calculation of dose distribution in the human body improves prediction of radiation loads. The additional shield reduces radiation exposure of human critical organs by -20% depending on their depth and body spatial orientation in the ISS compartment. PMID:26554132

  8. The effect of surgical titanium rods on proton therapy delivered for cervical bone tumors: experimental validation using an anthropomorphic phantom

    International Nuclear Information System (INIS)

    To investigate the effect of metal implants in proton radiotherapy, dose distributions of different, clinically relevant treatment plans have been measured in an anthropomorphic phantom and compared to treatment planning predictions. The anthropomorphic phantom, which is sliced into four segments in the cranio-caudal direction, is composed of tissue equivalent materials and contains a titanium implant in a vertebral body in the cervical region. GafChromic® films were laid between the different segments to measure the 2D delivered dose. Three different four-field plans have then been applied: a Single-Field-Uniform-Dose (SFUD) plan, both with and without artifact correction implemented, and an Intensity-Modulated-Proton-Therapy (IMPT) plan with the artifacts corrected. For corrections, the artifacts were manually outlined and the Hounsfield Units manually set to an average value for soft tissue. Results show a surprisingly good agreement between prescribed and delivered dose distributions when artifacts have been corrected, with > 97% and 98% of points fulfilling the gamma criterion of 3%/3 mm for both SFUD and the IMPT plans, respectively. In contrast, without artifact corrections, up to 18% of measured points fail the gamma criterion of 3%/3 mm for the SFUD plan. These measurements indicate that correcting manually for the reconstruction artifacts resulting from metal implants substantially improves the accuracy of the calculated dose distribution. (paper)

  9. Dosimetric study of a brachytherapy treatment of esophagus with Brazilian 192Ir sources using an anthropomorphic phantom

    International Nuclear Information System (INIS)

    Several radioisotopes are produced at Instituto de Pesquisas Energéticas e Nucleares for the use in medical treatments, including the activation of 192Ir sources. These sources are suitable for brachytherapy treatments, due to their low or high activity, depending on the concentration of 192Ir, easiness to manufacture, small size, stable daughter products and the possibility of re-utilization. They may be used for the treatment of prostate, cervix, head and neck, skin, breast, gallbladder, uterus, vagina, lung, rectum, and eye cancer treatment. In this work, the use of some 192Ir sources was studied for the treatment of esophagus cancer, especially the dose determination of important structures, such as those on the mediastinum. This was carried out utilizing a FASH anthropomorphic phantom and the MCNP5 Monte Carlo code to transport the radiation through matter. It was possible to observe that the doses at lungs, breast, esophagus, thyroid and heart were the highest, which was expected due to their proximity to the source. Therefore, the data are useful to assess the representative dose specific to brachytherapy treatments on the esophagus for radiation protection purposes. - Author-Highlights: • The use of brachytherapy sources was studied for the treatment of esophagus cancer. • FASH anthropomorphic phantom and MCNP5 Monte Carlo code were employed. • The doses at lungs, breast, esophagus, thyroid and heart were the highest. • The data is useful to assess the representative doses of treatments on the esophagus

  10. Digital anthropomorphic phantoms of non-rigid human respiratory and voluntary body motion for investigating motion correction in emission imaging

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

  12. Post-operative irradiation techniques for advanced larynx and hypopharynx cancer: a dosimetric comparison using anthropomorphic phantoms

    International Nuclear Information System (INIS)

    Objective: Using anthropomorphic phantoms, to compare the matchline inhomogeneity and spinal cord sparing aspects of 3 previously described post-operative irradiation techniques for patients status-post laryngectomy. Materials and Methods: Two anthropomorphic phantoms were constructed with human bones and tissue equivalent material. One was sectioned coronally and one sagittally/parasagittally. Both had a stoma placed 2 cm above the sternal notch. Film compressed between the sections served as the dosimetric tool. Simulation films were taken and fields outlined for 3 different techniques as follows: 1) University of Florida's (UF), Gainesville, 3-field, 2) modified Cleveland Clinic's (CC) Single Isocenter/Asymmetric Collimators (the matchline was feathered twice during this experiment) and 3) MD Anderson's (MDA) 3-field. Conformal blocks were constructed and ported to confirm accuracy. A formal treatment plan was completed and then executed on both phantoms to a scaled dose equivalent of 60 Gy to isocenter. The exposed film infrared optical density was converted into dose and then normalized to the prescription dose to yield isodose plots. Isodose zones exceeding 100% had to measure at least 15mm in diameter to be considered significant in accordance with ICRU Report 50 guidelines. Results: Table 1 indicates the degree of matchline inhomogeneity for each method with percent isodose values. Both the MDA and UF techniques provided a 1.0-1.5 cm non-irradiated spinal cord gap between the opposed laterals and AP supraclavicular (APS) fields while underdosing a considerable volume of tissue potentially at risk for recurrence along parasagittal planes at the level of field junction. The CC technique showed no such underdosed regions. Table 1. % Isodose Across Matchline. Anterior, Mid and Posterior coronal planes measure 4,7 and 9 cm deep from the anterior neck surface respectively. Conclusions: This anthropomorphic phantom dosimetric analysis suggests that all 3 methods

  13. Monte Carlo simulation of secondary radiation exposure from high-energy photon therapy using an anthropomorphic phantom

    International Nuclear Information System (INIS)

    The development of intensity-modulated radiotherapy treatments delivering large amounts of monitor units (MUs) recently raised concern about higher risks for secondary malignancies. In this study, optimised combinations of several variance reduction techniques (VRTs) have been implemented in order to achieve a high precision in Monte Carlo (MC) radiation transport simulations and the calculation of in- and out-of-field photon and neutron dose-equivalent distributions in an anthropomorphic phantom using MCNPX, v.2.7. The computer model included a Varian Clinac 2100C treatment head and a high-resolution head phantom. By means of the applied VRTs, a relative uncertainty for the photon dose-equivalent distribution of <1 % in-field and 15 % in average over the rest of the phantom could be obtained. Neutron dose equivalent, caused by photonuclear reactions in the linear accelerator components at photon energies of approximately >8 MeV, has been calculated. Relative uncertainty, calculated for each voxel, could be kept below 5 % in average over all voxels of the phantom. Thus, a very detailed neutron dose distribution could be obtained. The achieved precision now allows a far better estimation of both photon and especially neutron doses out-of-field, where neutrons can become the predominant component of secondary radiation. (authors)

  14. An anthropomorphic multimodality (CT/MRI) phantom prototype for end-to-end tests in radiation therapy

    CERN Document Server

    Gallas, Raya R; Runz, Armin; Niebuhr, Nina I; Jäkel, Oliver; Greilich, Steffen

    2014-01-01

    With the increasing complexity of external beam therapy, so-called "end-to-end" tests are intended to cover all steps from therapy planning to follow-up to fulfill the high demands on quality assurance. As magnetic resonance imaging (MRI) gains growing importance in the treatment process and established phantoms (such as the Alderson head) cannot be used for those tests, novel multimodality phantoms have to be developed. Here, we present a feasibility study for such a customizable multimodality head phantom. We used a set of patient CT images as the basis for the anthropomorphic head shape. The recipient - consisting of an epoxy resin - was produced using rapid prototyping (3D printing). The phantom recipient includes a nasal air cavity, two soft tissues volumes and cranial bone. Additionally a spherical tumor volume was positioned in the center. The volumes were filled with dipotassium phosphate-based cranial bone surrogate, agarose gel, and distilled water. The tumor volume was filled with normoxic dosimetr...

  15. SU-F-BRE-06: Evaluation of Patient CT Dose Reconstruction From 3D Diode Array Measurements Using Anthropomorphic Phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Huang, M; Benhabib, S; Cardan, R; Brezovich, I; Popple, R [The University of Alabama at Birmingham, Birmingham, AL (United States); Faught, A; Followill, D [The University of Texas MD Anderson Cancer Center, Houston, TX (United States)

    2014-06-15

    Purpose: To compare 3D reconstructed dose of IMRT plans from 3D diode array measurements with measurements in anthropomorphic phantoms. Methods: Six IMRT plans were created for the IROC Houston (RPC) head and neck (H and N) and lung phantoms following IROC Houston planning protocols. The plans included flattened and unflattened beam energies ranging from 6 MV to 15 MV and both static and dynamic MLC tecH and Niques. Each plan was delivered three times to the respective anthropomorphic phantom, each of which contained thermoluminescent dosimeters (TLDs) and radiochromic films (RCFs). The plans were also delivered to a Delta4 diode array (Scandidos, Uppsala, Sweden). Irradiations were done using a TrueBeam STx (Varian Medical Systems, Palo Alto, CA). The dose in the patient was calculated by the Delta4 software, which used the diode measurements to estimate incident energy fluence and a kernel-based pencil beam algorithm to calculate dose. The 3D dose results were compared with the TLD and RCF measurements. Results: In the lung, the average difference between TLDs and Delta4 calculations was 5% (range 2%–7%). For the H and N, the average differences were 2.4% (range 0%–4.5%) and 1.1% (range 0%–2%) for the high- and low-dose targets, respectively, and 12% (range 10%-13%) for the organ-at-risk simulating the spinal cord. For the RCF and criteria of 7%/4mm, 5%/3mm, and 3%/3mm, the average gamma-index pass rates were 95.4%, 85.7%, and 76.1%, respectively for the H and N and 76.2%, 57.8%, and 49.5% for the lung. The pass-rate in the lung decreased with increasing beam energy, as expected for a pencil beam algorithm. Conclusion: The H and N phantom dose reconstruction met the IROC Houston acceptance criteria for clinical trials; however, the lung phantom dose did not, most likely due to the inaccuracy of the pencil beam algorithm in the presence of low-density inhomogeneities. Work supported by PHS grant CA10953 and CA81647 (NCI, DHHS)

  16. Monte Carlo simulation of secondary radiation exposure from high-energy photon therapy using an anthropomorphic phantom.

    Science.gov (United States)

    Frankl, Matthias; Macián-Juan, Rafael

    2016-03-01

    The development of intensity-modulated radiotherapy treatments delivering large amounts of monitor units (MUs) recently raised concern about higher risks for secondary malignancies. In this study, optimised combinations of several variance reduction techniques (VRTs) have been implemented in order to achieve a high precision in Monte Carlo (MC) radiation transport simulations and the calculation of in- and out-of-field photon and neutron dose-equivalent distributions in an anthropomorphic phantom using MCNPX, v.2.7. The computer model included a Varian Clinac 2100C treatment head and a high-resolution head phantom. By means of the applied VRTs, a relative uncertainty for the photon dose-equivalent distribution of 8 MeV, has been calculated. Relative uncertainty, calculated for each voxel, could be kept below 5 % in average over all voxels of the phantom. Thus, a very detailed neutron dose distribution could be obtained. The achieved precision now allows a far better estimation of both photon and especially neutron doses out-of-field, where neutrons can become the predominant component of secondary radiation. PMID:26311702

  17. Dosimetric impact of interplay effect in lung IMRT and VMAT treatment using in-house dynamic thorax phantom

    Science.gov (United States)

    Mukhlisin; Pawiro, S. A.

    2016-03-01

    Tumor motion due to patient's respiratory is a significant problem in radiotherapy treatment of lung cancer. The purpose of this project is to study the interplay effect through dosimetry verification between the calculated and delivered dose, as well as the dosimetric impact of leaf interplay with breathing-induced tumor motion in IMRT and VMAT treatment. In this study, a dynamic thorax phantom was designed and constructed for dosimetry measurement. The phantom had a linear sinusoidal tumor motion toward superior-inferior direction with variation of amplitudes and periods. TLD-100 LiF:Mg,Ti and Gafchromic EBT2 film were used to measure dose in the midpoint target and the spinal cord. The IMRT and VMAT treatment had prescription dose of 200 cGy per fraction. The dosimetric impact due to interplay effect during IMRT and VMAT treatment were resulted in the range of 0.5% to -6.6% and 0.9% to -5.3% of target dose reduction, respectively. Meanwhile, mean dose deviation of spinal cord in IMRT and VMAT treatment were around 1.0% to -6.9% and 0.9% to -6.3%, respectively. The results showed that if respiratory management technique were not implemented, the presence of lung tumor motion during dose delivery in IMRT and VMAT treatment causes dose discrepancies inside tumor volume.

  18. Poster — Thur Eve — 76: Dosimetric Comparison of Pinnacle and iPlan Algorithms with an Anthropomorphic Lung Phantom

    International Nuclear Information System (INIS)

    Our goal is to compare the dosimetric accuracy of the Pinnacle-3 9.2 Collapsed Cone Convolution Superposition (CCCS) and the iPlan 4.1 Monte Carlo (MC) and Pencil Beam (PB) algorithms in an anthropomorphic lung phantom using measurement as the gold standard. Ion chamber measurements were taken for 6, 10, and 18 MV beams in a CIRS E2E SBRT Anthropomorphic Lung Phantom, which mimics lung, spine, ribs, and tissue. The plan implemented six beams with a 5×5 cm2 field size, delivering a total dose of 48 Gy. Data from the planning systems were computed at the treatment isocenter in the left lung, and two off-axis points, the spinal cord and the right lung. The measurements were taken using a pinpoint chamber. The best results between data from the algorithms and our measurements occur at the treatment isocenter. For the 6, 10, and 18 MV beams, iPlan 4.1 MC software performs the best with 0.3%, 0.2%, and 4.2% absolute percent difference from measurement, respectively. Differences between our measurements and algorithm data are much greater for the off-axis points. The best agreement seen for the right lung and spinal cord is 11.4% absolute percent difference with 6 MV iPlan 4.1 PB and 18 MV iPlan 4.1 MC, respectively. As energy increases absolute percent difference from measured data increases up to 54.8% for the 18 MV CCCS algorithm. This study suggests that iPlan 4.1 MC computes peripheral dose and target dose in the lung more accurately than the iPlan 4.1 PB and Pinnicale CCCS algorithms

  19. CT head-scan dosimetry in an anthropomorphic phantom and associated measurement of ACR accreditation-phantom imaging metrics under clinically representative scan conditions

    Energy Technology Data Exchange (ETDEWEB)

    Brunner, Claudia C.; Stern, Stanley H.; Chakrabarti, Kish [U.S. Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, Maryland 20993 (United States); Minniti, Ronaldo [National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899 (United States); Parry, Marie I. [Walter Reed National Military Medical Center, 8901 Rockville Pike, Bethesda, Maryland 20889 (United States); Skopec, Marlene [National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892 (United States)

    2013-08-15

    Purpose: To measure radiation absorbed dose and its distribution in an anthropomorphic head phantom under clinically representative scan conditions in three widely used computed tomography (CT) scanners, and to relate those dose values to metrics such as high-contrast resolution, noise, and contrast-to-noise ratio (CNR) in the American College of Radiology CT accreditation phantom.Methods: By inserting optically stimulated luminescence dosimeters (OSLDs) in the head of an anthropomorphic phantom specially developed for CT dosimetry (University of Florida, Gainesville), we measured dose with three commonly used scanners (GE Discovery CT750 HD, Siemens Definition, Philips Brilliance 64) at two different clinical sites (Walter Reed National Military Medical Center, National Institutes of Health). The scanners were set to operate with the same data-acquisition and image-reconstruction protocols as used clinically for typical head scans, respective of the practices of each facility for each scanner. We also analyzed images of the ACR CT accreditation phantom with the corresponding protocols. While the Siemens Definition and the Philips Brilliance protocols utilized only conventional, filtered back-projection (FBP) image-reconstruction methods, the GE Discovery also employed its particular version of an adaptive statistical iterative reconstruction (ASIR) algorithm that can be blended in desired proportions with the FBP algorithm. We did an objective image-metrics analysis evaluating the modulation transfer function (MTF), noise power spectrum (NPS), and CNR for images reconstructed with FBP. For images reconstructed with ASIR, we only analyzed the CNR, since MTF and NPS results are expected to depend on the object for iterative reconstruction algorithms.Results: The OSLD measurements showed that the Siemens Definition and the Philips Brilliance scanners (located at two different clinical facilities) yield average absorbed doses in tissue of 42.6 and 43.1 m

  20. SU-E-T-607: An Experimental Validation of Gamma Knife Based Convolution Algorithm On Solid Acrylic Anthropomorphic Phantom

    Energy Technology Data Exchange (ETDEWEB)

    Gopishankar, N; Bisht, R K [All India Institute of Medical Sciences, New Delhi (India)

    2014-06-01

    Purpose: To perform dosimetric evaluation of convolution algorithm in Gamma Knife (Perfexion Model) using solid acrylic anthropomorphic phantom. Methods: An in-house developed acrylic phantom with ion chamber insert was used for this purpose. The middle insert was designed to fit ion chamber from top(head) as well as from bottom(neck) of the phantom, henceforth measurement done at two different positions simultaneously. Leksell frame fixed to phantom simulated patient treatment. Prior to dosimetric study, hounsfield units and electron density of acrylic material were incorporated into the calibration curve in the TPS for convolution algorithm calculation. A CT scan of phantom with ion chamber (PTW Freiberg, 0.125cc) was obtained with following scanning parameters: Tube voltage-110kV, Slice thickness-1mm and FOV-240mm. Three separate single shot plans were generated in LGP TPS (Version 10.1.) with collimators 16mm, 8mm and 4mm respectively for both ion chamber positions. Both TMR10 and Convolution algorithm based planning (CABP) were used for dose calculation. A dose of 6Gy at 100% isodose was prescribed at centre of ion chamber visible in the CT scan. The phantom with ion chamber was positioned in the treatment couch for dose delivery. Results: The ion chamber measured dose was 5.98Gy for 16mm collimator shot plan with less than 1% deviation for convolution algorithm whereas with TMR10 measured dose was 5.6Gy. For 8mm and 4mm collimator plan merely a dose of 3.86Gy and 2.18Gy respectively were delivered at TPS calculated time for CABP. Conclusion: CABP is expected to perform accurate prediction of time for dose delivery for all collimators, but significant variation in measured dose was observed for 8mm and 4mm collimator which may be due collimator size effect. Effect of metal artifacts caused by pins and frame on the CT scan also may have role in misinterpreting CABP. The study carried out requires further investigation.

  1. Assessment of phase based dose modulation for improved dose efficiency in cardiac CT on an anthropomorphic motion phantom

    Science.gov (United States)

    Budde, Adam; Nilsen, Roy; Nett, Brian

    2014-03-01

    State of the art automatic exposure control modulates the tube current across view angle and Z based on patient anatomy for use in axial full scan reconstructions. Cardiac CT, however, uses a fundamentally different image reconstruction that applies a temporal weighting to reduce motion artifacts. This paper describes a phase based mA modulation that goes beyond axial and ECG modulation; it uses knowledge of the temporal view weighting applied within the reconstruction algorithm to improve dose efficiency in cardiac CT scanning. Using physical phantoms and synthetic noise emulation, we measure how knowledge of sinogram temporal weighting and the prescribed cardiac phase can be used to improve dose efficiency. First, we validated that a synthetic CT noise emulation method produced realistic image noise. Next, we used the CT noise emulation method to simulate mA modulation on scans of a physical anthropomorphic phantom where a motion profile corresponding to a heart rate of 60 beats per minute was used. The CT noise emulation method matched noise to lower dose scans across the image within 1.5% relative error. Using this noise emulation method to simulate modulating the mA while keeping the total dose constant, the image variance was reduced by an average of 11.9% on a scan with 50 msec padding, demonstrating improved dose efficiency. Radiation dose reduction in cardiac CT can be achieved while maintaining the same level of image noise through phase based dose modulation that incorporates knowledge of the cardiac reconstruction algorithm.

  2. Secondary absorbed doses from light ion irradiation in anthropomorphic phantoms representing an adult male and a 10 year old child

    International Nuclear Information System (INIS)

    Secondary organ absorbed doses were calculated by Monte Carlo simulations with the SHIELD-HIT07 code coupled with the mathematical anthropomorphic phantoms CHILD-HIT and ADAM-HIT. The simulated irradiations were performed with primary 1H, 4He, 7Li, 12C and 16O ion beams in the energy range 100-400 MeV/u which were directly impinging on the phantoms, i.e. approximating scanned beams, and with a simplified beamline for 12C irradiation. The evaluated absorbed doses to the out-of-field organs were in the range 10-6 to 10-1 mGy per target Gy and with standard deviations 0.5-20%. While the contribution to the organ absorbed doses from secondary neutrons dominated in the ion beams of low atomic number Z, the produced charged fragments and their subsequent charged secondaries of higher generations became increasingly important for the secondary dose delivery as Z of the primary ions increased. As compared to the simulated scanned 12C ion beam, the implementation of a simplified beamline for prostate irradiation with 12C ions resulted in an increase of 2-50 times in the organ absorbed doses depending on the distance from the target volume. Comparison of secondary organ absorbed doses delivered by 1H and 12C beams showed smaller differences when the RBE for local tumor control of the ions was considered and normalization to the RBE-weighted dose to the target was performed.

  3. Validation of an in-vivo proton beam range check method in an anthropomorphic pelvic phantom using dose measurements

    International Nuclear Information System (INIS)

    Purpose: In-vivo dosimetry and beam range verification in proton therapy could play significant role in proton treatment validation and improvements. In-vivo beam range verification, in particular, could enable new treatment techniques one of which could be the use of anterior fields for prostate treatment instead of opposed lateral fields as in current practice. This paper reports validation study of an in-vivo range verification method which can reduce the range uncertainty to submillimeter levels and potentially allow for in-vivo dosimetry. Methods: An anthropomorphic pelvic phantom is used to validate the clinical potential of the time-resolved dose method for range verification in the case of prostrate treatment using range modulated anterior proton beams. The method uses a 3 × 4 matrix of 1 mm diodes mounted in water balloon which are read by an ADC system at 100 kHz. The method is first validated against beam range measurements by dose extinction measurements. The validation is first completed in water phantom and then in pelvic phantom for both open field and treatment field configurations. Later, the beam range results are compared with the water equivalent path length (WEPL) values computed from the treatment planning system XIO. Results: Beam range measurements from both time-resolved dose method and the dose extinction method agree with submillimeter precision in water phantom. For the pelvic phantom, when discarding two of the diodes that show sign of significant range mixing, the two methods agree with ±1 mm. Only a dose of 7 mGy is sufficient to achieve this result. The comparison to the computed WEPL by the treatment planning system (XIO) shows that XIO underestimates the protons beam range. Quantifying the exact XIO range underestimation depends on the strategy used to evaluate the WEPL results. To our best evaluation, XIO underestimates the treatment beam range between a minimum of 1.7% and maximum of 4.1%. Conclusions: Time-resolved dose

  4. SU-D-BRE-01: A Realistic Breathing Phantom of the Thorax for Testing New Motion Mitigation Techniques with Scanning Proton Therapy

    International Nuclear Information System (INIS)

    Purpose: A prototype breathing phantom (named LuCa) has been developed which simulates the anatomy and motion of a patient thorax.In this work, we describe the results of the first commissioning tests with LuCa. Methods: The phantom provides a close representation of the human thorax. The lungs,contained within a tissue-equivalent ribcage and skin,are made from a polymer foam,which is inflated and deflated using a custommade ventilator. A tumor is simulated using a wooden ball with cutplanes for placing GafChromic films. The ventilator,controlled with Labview software,simulates a full range of breathing motion types.Commissioning tests were performed to assess its performance using imaging (CT and radiographic) and film dosimetry as follows:i)maximum Tumor excursion at acceptable pressure ranges, ii)tumor Motion repeatability between breathing periods,iii)reproducibility between measurement days,iv)tumor-to-surface motion correlation and v)reproducibility of film positioning in phantom. Results: The phantom can generate repeatable motion patterns with sin4,sin,breath-hold (tumor amplitude repeatability 2=0.92. Reproducibility of film positioning within the thorax was within 0.9mm, and maximum 3° error from the coronal plane. Film measurements revealed that the film repositioning error yields relative errors in the mean dose over the planned target volume (PTV) of up to 2.5% and 4.5% for films at the center and on the edge of the PTV respectively. Conclusion: Commissioning tests have shown that the LuCa phantom can produce tumor motion with excellent repeatability. However,a poorer performance in reproducibility of tumor amplitude for a given peak pressure week-to-week. Film set-up reproducibility is adequate for detection of dosimetric errors resulting from motion of >3%. This work is funded by Swiss National Fund Grants 320030-127569 and 320030-1493942-1

  5. Monte Carlo package for simulating radiographic images of realistic anthropomorphic phantoms described by triangle meshes

    Science.gov (United States)

    Badal, Andreu; Kyprianou, Iacovos; Badano, Aldo; Sempau, Josep; Myers, Kyle J.

    2007-03-01

    X-ray imaging system optimization increases the benefit-to-cost ratio by reducing the radiation dose to the patient while maximizing image quality. We present a new simulation tool for the generation of realistic medical x-ray images for assessment and optimization of complete imaging systems. The Monte Carlo code simulates radiation transport physics using the subroutine package PENELOPE, which accurately simulates the transport of electrons and photons within the typical medical imaging energy range. The new code implements a novel object-oriented geometry package that allows simulations with homogeneous objects of arbitrary shapes described by triangle meshes. The flexibility of this code, which uses the industry standard PLY input-file format, allows the use of detailed anatomical models developed using computer-aided design tools applied to segmented CT and MRI data. The use of triangle meshes highly simplifies the ray-tracing algorithm without reducing the generality of the code, since most surface models can be tessellated into triangles while retaining their geometric details. Our algorithm incorporates an octree spatial data structure to sort the triangles and accelerate the simulation, reaching execution speeds comparable to the original quadric geometry model of PENELOPE. Coronary angiograms were simulated using a tessellated version of the NURBS-based Cardiac-Torso (NCAT) phantom. The phantom models 330 objects, comprised in total of 5 million triangles. The dose received by each organ and the contribution of the different scattering processes to the final image were studied in detail.

  6. Radiation Pattern Measurement of a Low-Profile Wearable Antenna Using an Optical Fibre and a Solid Anthropomorphic Phantom

    Directory of Open Access Journals (Sweden)

    Tian Hong Loh

    2014-08-01

    Full Text Available This paper presents a study into radiation pattern measurements of an electrically small dielectric resonator antenna (DRA operating between 2.4 and 2.5 GHz in the industrial, scientific and medical (ISM radio band for body-centric wireless communication applications. To eliminate the distortion of the radiation pattern associated with the unwanted radiation from a metallic coaxial cable feeding the antenna we have replaced it with a fibre optic feed and an electro-optical (EO transducer. The optical signal is then converted back to RF using an Opto-Electric Field Sensor (OEFS system. To ensure traceable measurements of the radiation pattern performance of the wearable antenna a generic head and torso solid anthropomorphic phantom model has been employed. Furthermore, to illustrate the benefits of the method, numerical simulations of the co-polar and cross-polar H-plane radiation patterns at 2.4, 2.45, and 2.5 GHz are compared with the measured results obtained using: (i an optical fibre; and (ii a metallic coaxial cable.

  7. Poster — Thur Eve — 09: Evaluation of electrical impedance and computed tomography fusion algorithms using an anthropomorphic phantom

    Energy Technology Data Exchange (ETDEWEB)

    Chugh, Brige Paul; Krishnan, Kalpagam; Liu, Jeff; Kohli, Kirpal [BC Cancer Agency — Fraser Valley Centre (Canada)

    2014-08-15

    Integration of biological conductivity information provided by Electrical Impedance Tomography (EIT) with anatomical information provided by Computed Tomography (CT) imaging could improve the ability to characterize tissues in clinical applications. In this paper, we report results of our study which compared the fusion of EIT with CT using three different image fusion algorithms, namely: weighted averaging, wavelet fusion, and ROI indexing. The ROI indexing method of fusion involves segmenting the regions of interest from the CT image and replacing the pixels with the pixels of the EIT image. The three algorithms were applied to a CT and EIT image of an anthropomorphic phantom, constructed out of five acrylic contrast targets with varying diameter embedded in a base of gelatin bolus. The imaging performance was assessed using Detectability and Structural Similarity Index Measure (SSIM). Wavelet fusion and ROI-indexing resulted in lower Detectability (by 35% and 47%, respectively) yet higher SSIM (by 66% and 73%, respectively) than weighted averaging. Our results suggest that wavelet fusion and ROI-indexing yielded more consistent and optimal fusion performance than weighted averaging.

  8. Experience of development and testing of a new model of an anthropomorphic radiodosimetric phantom of the human body ARDF-10 'Roman'

    International Nuclear Information System (INIS)

    In 2006-2010 by the commission of the Radiation and Nuclear Safety Authority in Finland applied scientific research and development of a new model of an anthropomorphic radio dosimetric phantom of the human body (the Phantom) were performed, after the development of the production technology and initial testing in 2010-2012 the first serial copy of the Phantom under the name ARDF-10 ROMAN was produced. The main application of the new model of the Phantom ARDF-10 ROMAN: - increase of the precision of calibration and implementation of the periodic monitoring of Whole body counters (WBC) equipment, standardization of measurement procedure for inter-laboratory comparisons of the incorporated activity. - metrological support of the development and implementation of new methods for human radiation spectrometry: identification of radionuclide content of incorporated activity in the human body; measurements of the activity of incorporated technogenic and natural radionuclides in the whole body and in the lungs; measurements of 90Sr content in the bone tissue. Study of the mechanisms of the intake, distribution, accumulation and excretion of the radionuclides in the human body, such as: daughter products of 222Rn decay in the respiratory tract, 241Am, other transuranic elements; isotopes of iodine in the thyroid gland; radiopharmaceuticals administered to patients for diagnostic and medicinal purposes. Obtaining estimates of spatial-temporal distribution of individual internal exposure dose of a human. The result of the work of recent years has been the creation of hygienic safe standard sample of an anthropomorphic radio dosimetric phantom of the human body ARDF-10 ROMAN, consisting of 4 anthropometric models of body parts, which are independent assembly units (head phantom, neck phantom, torso phantom, knee phantom). Phantom models are made from simulators of bone, soft (muscle) and lungs biological tissue. The Phantom contains 28 separate elements. To the first Phantom

  9. Evaluation of patient doses from upper gastrointestinal tract examinations based on the dosimetry in an anthropomorphic phantom

    International Nuclear Information System (INIS)

    The objective of this study was to evaluate organ dose and effective dose to patients from examinations of the upper gastrointestinal (GI) tract. Absorbed doses of various tissues and organs were measured using novel photodiode dosimeters installed in an anthropomorphic phantom representing a standard Japanese adult body. The organ dose and the effective dose were assessed from the absorbed doses according to the definitions seen in the publications of the International Commission on Radiological Protection. Dose measurements were performed for each projection of the upper GI tract examination in seven procedures at four hospitals and in a mobile coach, and organ and effective doses were assessed for each procedure. Organ doses obtained in the observation areas such as the stomach, esophagus and colon were in the order of several to more than 60 mGy, though they decreased to less than 1 mGy for tissues and organs distant from the observation areas. Organ doses and effective doses differed largely according to tube voltage, filtration and tube current or mAs value of the x-ray generator used, and by examination protocol, number of images, fluoroscopy time, and imaging units such as screen/film, computed radiography, digital radiography and flat panel detector. The number of images and the fluoroscopy time were 7 and 1.5 min for the examination in the mobile coach, and 18-22 and 2-6 min in the hospitals. Evaluated effective dose for the examination in the mobile coach was 2.9 mSv, and that in the hospitals ranged from 4.0-13.4 mSv at a ratio of more than three. (author)

  10. Evaluation of the medical and occupational shielding in cerebral angiography using Monte Carlo simulations and virtual anthropomorphic phantoms

    Science.gov (United States)

    Santos, William S.; Neves, Lucio P.; Perini, Ana P.; Caldas, Linda V. E.; Maia, Ana F.

    2015-12-01

    Cerebral angiography exams may provide valuable diagnostic information for the patients with suspect of cerebral diseases, but it may also deliver high doses of radiation to the patients and medical staff. In order to evaluate the medical and occupational expositions from different irradiation conditions, Monte Carlo (MC) simulations were employed. Virtual anthropomorphic phantoms (MASH) were used to represent the patient and the physician inside a typical fluoroscopy room, also simulated in details, incorporated in the MCNPX 2.7.0 MC code. The evaluation was carried out by means of dose conversion coefficients (CCs) for equivalent (H) and effective (E) doses normalized by the air kerma-area product (KAP). The CCs for the surface entrance dose of the patient (ESD) and equivalent dose for the eyes of the medical staff were determined, because CA exams present higher risks for those organs. The tube voltage was 80 kVp, and Al filters with thicknesses of 2.5 mm, 3.5 mm and 4.0 mm were positioned in the beams. Two projections were simulated: posterior-anterior (PA) and right-lateral (RLAT). In all situations there was an increase of the CC values with the increase of the Al filtration. The highest dose was obtained for a RLAT projection with a 4.0 mm Al filter. In this projection, the ESD/KAP and E/KAP values to patient were 11 (14%) mGy/Gy cm2 and 0.12 (0.1%) mSv/Gy cm2, respectively. For the physician, the use of shield lead glass suspended and lead curtain attached to the surgical table resulted in a significant reduction of the CCs. The use of MC simulations proved to be a very important tool in radiation protection dosimetry, and specifically in this study several parameters could be evaluated, which would not be possible experimentally.

  11. SU-E-CAMPUS-T-03: Development and Implementation of An Anthropomorphic Pediatric Spine Phantom for the Assessment of Craniospinal Irradiation Procedures in Proton Therapy

    International Nuclear Information System (INIS)

    Purpose: To design an anthropomorphic pediatric spine phantom for use in the evaluation of proton therapy facilities for clinical trial participation by the Imaging and Radiation Oncology Core (IROC) Houston QA Center (formerly RPC). Methods: This phantom was designed to perform an end-to-end audit of the proton spine treatment process, including simulation, dose calculation by the treatment planning system (TPS), and proton treatment delivery. The design incorporated materials simulating the thoracic spinal column of a pediatric patient, along with two thermoluminescent dosimeter (TLD)-100 capsules and radiochromic film embedded in the phantom for dose evaluation. Fourteen potential materials were tested to determine relative proton stopping power (RSP) and Hounsfield unit (HU) values. Each material was CT scanned at 120kVp, and the RSP was obtained from depth ionization scans using the Zebra multilayer ion chamber (MLIC) at two energies: 160 MeV and 250 MeV. To determine tissue equivalency, the measured RSP for each material was compared to the RSP calculated by the Eclipse TPS for a given HU. Results: The materials selected as bone, tissue, and cartilage substitutes were Techron HPV Bearing Grade (Boedeker Plastics, Inc.), solid water, and blue water, respectively. The RSP values did not differ by more than 1.8% between the two energies. The measured RSP for each selected material agreed with the RSP calculated by the Eclipse TPS within 1.2%. Conclusion: An anthropomorphic pediatric proton spine phantom was designed to evaluate proton therapy delivery. The inclusion of multiple tissue substitutes increases heterogeneity and the level of difficulty for institutions to successfully treat the phantom. The following attributes will be evaluated: absolute dose agreement, distal range, field width, junction match and right/left dose profile alignment. The phantom will be tested at several institutions using a 5% dose agreement criterion, and a 5%/3mm gamma analysis

  12. SU-E-CAMPUS-T-03: Development and Implementation of An Anthropomorphic Pediatric Spine Phantom for the Assessment of Craniospinal Irradiation Procedures in Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, D; Summers, P; Followill, D; Sahoo, N; Mahajan, A; Stingo, F; Kry, S [UT MD Anderson Cancer Center, Houston, TX (United States)

    2014-06-15

    Purpose: To design an anthropomorphic pediatric spine phantom for use in the evaluation of proton therapy facilities for clinical trial participation by the Imaging and Radiation Oncology Core (IROC) Houston QA Center (formerly RPC). Methods: This phantom was designed to perform an end-to-end audit of the proton spine treatment process, including simulation, dose calculation by the treatment planning system (TPS), and proton treatment delivery. The design incorporated materials simulating the thoracic spinal column of a pediatric patient, along with two thermoluminescent dosimeter (TLD)-100 capsules and radiochromic film embedded in the phantom for dose evaluation. Fourteen potential materials were tested to determine relative proton stopping power (RSP) and Hounsfield unit (HU) values. Each material was CT scanned at 120kVp, and the RSP was obtained from depth ionization scans using the Zebra multilayer ion chamber (MLIC) at two energies: 160 MeV and 250 MeV. To determine tissue equivalency, the measured RSP for each material was compared to the RSP calculated by the Eclipse TPS for a given HU. Results: The materials selected as bone, tissue, and cartilage substitutes were Techron HPV Bearing Grade (Boedeker Plastics, Inc.), solid water, and blue water, respectively. The RSP values did not differ by more than 1.8% between the two energies. The measured RSP for each selected material agreed with the RSP calculated by the Eclipse TPS within 1.2%. Conclusion: An anthropomorphic pediatric proton spine phantom was designed to evaluate proton therapy delivery. The inclusion of multiple tissue substitutes increases heterogeneity and the level of difficulty for institutions to successfully treat the phantom. The following attributes will be evaluated: absolute dose agreement, distal range, field width, junction match and right/left dose profile alignment. The phantom will be tested at several institutions using a 5% dose agreement criterion, and a 5%/3mm gamma analysis

  13. Design and development of an anthropomorphic phantom equipped with detectors in order to evaluate the effective dose E at workplaces: feasibility study

    International Nuclear Information System (INIS)

    My PhD study aims to determine the feasibility to design and develop, for photon fields, an anthropomorphic phantom equipped with detectors in order to evaluate the effective dose E at workplaces. First of all, the energy losses within the organs are calculated using the M.C.N.P.X. Monte Carlo code, in order to determine the detection positions within the different organs. Then, to decrease the number of detection positions, the organ contribution to the effective dose is studied. Finally, the characteristics of the detectors to insert and the characteristics of the phantom to use are deduced. The results show that 24 or 23 detection positions, according to the wT values (publication 60 or new recommendations of the ICRP), give a E estimation with an uncertainty of ±15 % from 50 keV to 4 MeV. Moreover, the interest of such an instrument is underlined while comparing the E estimation by the personal dose equivalent Hp to the E estimation by the instrumented phantom when the phantom is irradiated by point sources (worker in front of a glove box for example). Last, after the detector and phantom characteristic determination, two types of detectors and one type of phantom are selected. However, for the detectors mainly, developments are necessary. Follow up this study, the characterization and the adaptation of the detectors to the project would be interesting. Furthermore, the study to mixed photon-neutrons would be required the needs of the radiological protection community. (author)

  14. Use of VAP3D software in the construction of pathological anthropomorphic phantoms for dosimetric evaluations; Uso do software VAP3D na construcao de fantomas antropomorficos patologicos para avaliacoes dosimetricas

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Lindeval Fernandes de [Universidade Federal de Pernambuco (DEM/UFPE), Recife, PE (Brazil). Dept. de Engenharia Mecanica; Vieira, Jose Wilson [Instituto Federal de Educacao, Ciencia e Tecnologia de Pernambuco, Recife, PE (Brazil); Lima, Fernando R.A., E-mail: falima@cnen.gov.b [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2011-10-26

    This paper performs a new type of dosimetric evaluation, where it was used a phantom of pathological voxels (representative phantom of sick person). The software VAP3D (Visualization and Analysis of Phantoms 3D) were used for, from a healthy phantom (phantom representative of healthy person), to introduce three dimensional regions to simulate tumors. It was used the Monte Carlo ESGnrc code to simulate the X ray photon transport, his interaction with matter and evaluation of absorbed dose in organs and tissues from thorax region of the healthy phantom and his pathological version. This is a computer model of typical exposure for programming the treatments in radiodiagnostic

  15. Sensitivity and accuracy of volumetry of pulmonary nodules on low-dose 16- and 64-row multi-detector CT: an anthropomorphic phantom study

    International Nuclear Information System (INIS)

    To assess the sensitivity of detection and accuracy of volumetry by manual and semi-automated quantification of artificial pulmonary nodules in an anthropomorphic thoracic phantom on low-dose CT. Fifteen artificial spherical nodules (diameter 3, 5, 8, 10 and 12 mm; CT densities -800, -630 and +100 HU) were randomly placed inside an anthropomorphic thoracic phantom. The phantom was examined on 16- and 64-row multidetector CT with a low-dose protocol. Two independent blinded observers screened for pulmonary nodules. Nodule diameter was measured manually, and volume calculated. For solid nodules (+100 HU), diameter and volume were also evaluated by semi-automated software. Differences in observed volumes between the manual and semi-automated method were evaluated by a t-test. Sensitivity was 100 % for all nodules of >5 mm and larger, 60-80 % for solid and 0-20 % for non-solid 3-mm nodules. No false-positive nodules but high inter-observer reliability and inter-technique correlation were found. Volume was underestimated manually by 24.1 ± 14.0 % for nodules of any density, and 26.4 ± 15.5 % for solid nodules, compared with 7.6 ± 8.5 % (P 5 mm in diameter. Semi-automated volumetry yielded more accurate nodule volumes than manual measurements. (orig.)

  16. SU-D-BRE-01: A Realistic Breathing Phantom of the Thorax for Testing New Motion Mitigation Techniques with Scanning Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Perrin, R; Peroni, M; Bernatowicz, K; Zakova, M; Knopf, A; Safai, S [Paul Scherrer Institut, Psi-villigen, Aargau (Switzerland); Parkel, T [CSEM, Swiss Centre of Electronics and Microtechnology, Landquart, Graubunden (Switzerland)

    2014-06-01

    Purpose: A prototype breathing phantom (named LuCa) has been developed which simulates the anatomy and motion of a patient thorax.In this work, we describe the results of the first commissioning tests with LuCa. Methods: The phantom provides a close representation of the human thorax. The lungs,contained within a tissue-equivalent ribcage and skin,are made from a polymer foam,which is inflated and deflated using a custommade ventilator. A tumor is simulated using a wooden ball with cutplanes for placing GafChromic films. The ventilator,controlled with Labview software,simulates a full range of breathing motion types.Commissioning tests were performed to assess its performance using imaging (CT and radiographic) and film dosimetry as follows:i)maximum Tumor excursion at acceptable pressure ranges, ii)tumor Motion repeatability between breathing periods,iii)reproducibility between measurement days,iv)tumor-to-surface motion correlation and v)reproducibility of film positioning in phantom. Results: The phantom can generate repeatable motion patterns with sin{sup 4},sin,breath-hold (tumor amplitude repeatability <0.5mm over 10min),aswell as patient-specific motion types. Maximum excursions of the tumor are 20mm and 14mm for the large and small tumor inserts respectively. Amplitude reproducibility (Coefficient of Variation) averaged at 16% for the workable pressure range over 2 months. Good correlation between tumor and surface motion was found with R{sup 2}=0.92. Reproducibility of film positioning within the thorax was within 0.9mm, and maximum 3° error from the coronal plane. Film measurements revealed that the film repositioning error yields relative errors in the mean dose over the planned target volume (PTV) of up to 2.5% and 4.5% for films at the center and on the edge of the PTV respectively. Conclusion: Commissioning tests have shown that the LuCa phantom can produce tumor motion with excellent repeatability. However,a poorer performance in reproducibility of

  17. Scatter estimation and removal of anti-scatter grid-line artifacts from anthropomorphic head phantom images taken with a high resolution image detector

    Science.gov (United States)

    Rana, R.; Jain, A.; Shankar, A.; Bednarek, D. R.; Rudin, S.

    2016-03-01

    In radiography, one of the best methods to eliminate image-degrading scatter radiation is the use of anti-scatter grids. However, with high-resolution dynamic imaging detectors, stationary anti-scatter grids can leave grid-line shadows and moiré patterns on the image, depending upon the line density of the grid and the sampling frequency of the x-ray detector. Such artifacts degrade the image quality and may mask small but important details such as small vessels and interventional device features. Appearance of these artifacts becomes increasingly severe as the detector spatial resolution is improved. We have previously demonstrated that, to remove these artifacts by dividing out a reference grid image, one must first subtract the residual scatter that penetrates the grid; however, for objects with anatomic structure, scatter varies throughout the FOV and a spatially differing amount of scatter must be subtracted. In this study, a standard stationary Smit-Rontgen X-ray grid (line density - 70 lines/cm, grid ratio - 13:1) was used with a high-resolution CMOS detector, the Dexela 1207 (pixel size - 75 micron) to image anthropomorphic head phantoms. For a 15 x 15cm FOV, scatter profiles of the anthropomorphic head phantoms were estimated then iteratively modified to minimize the structured noise due to the varying grid-line artifacts across the FOV. Images of the anthropomorphic head phantoms taken with the grid, before and after the corrections, were compared demonstrating almost total elimination of the artifact over the full FOV. Hence, with proper computational tools, antiscatter grid artifacts can be corrected, even during dynamic sequences.

  18. Evaluation of Iterative Reconstruction Method and Attenuation Correction in Brain Dopamine Transporter SPECT Using an Anthropomorphic Striatal Phantom

    Science.gov (United States)

    Maebatake, Akira; Imamura, Ayaka; Kodera, Yui; Yamashita, Yasuo; Himuro, Kazuhiko; Baba, Shingo; Miwa, Kenta; Sasaki, Masayuki

    2016-01-01

    Objective(s): The aim of this study was to determine the optimal reconstruction parameters for iterative reconstruction in different devices and collimators for dopamine transporter (DaT) single-photon emission computed tomography (SPECT). The results were compared between filtered back projection (FBP) and different attenuation correction (AC) methods. Methods: An anthropomorphic striatal phantom was filled with 123I solutions at different striatum-to-background radioactivity ratios. Data were acquired using two SPECT/CT devices, equipped with a low-to-medium-energy general-purpose collimator (cameras A-1 and B-1) and a low-energy high-resolution (LEHR) collimator (cameras A-2 and B-2). The SPECT images were once reconstructed by FBP using Chang’s AC and once by ordered subset expectation maximization (OSEM) using both CTAC and Chang’s AC; moreover, scatter correction was performed. OSEM on cameras A-1 and A-2 included resolution recovery (RR). The images were analyzed, using the specific binding ratio (SBR). Regions of interest for the background were placed on both frontal and occipital regions. Results: The optimal number of iterations and subsets was 10i10s on camera A-1, 10i5s on camera A-2, and 7i6s on cameras B-1 and B-2. The optimal full width at half maximum of the Gaussian filter was 2.5 times the pixel size. In the comparison between FBP and OSEM, the quality was superior on OSEM-reconstructed images, although edge artifacts were observed in cameras A-1 and A-2. The SBR recovery of OSEM was higher than that of FBP on cameras A-1 and A-2, while no significant difference was detected on cameras B-1 and B-2. Good linearity of SBR was observed in all cameras. In the comparison between Chang’s AC and CTAC, a significant correlation was observed on all cameras. The difference in the background region influenced SBR differently in Chang’s AC and CTAC on cameras A-1 and B-1. Conclusion: Iterative reconstruction improved image quality on all cameras

  19. ROC evaluation of SPECT myocardial lesion detectability with and without single iteration non-uniform Chang attenuation compensation using an anthropomorphic female phantom

    International Nuclear Information System (INIS)

    The purpose of this work was to evaluate lesion detectability with and without nonuniform attenuation compensation (AC) in myocardial perfusion SPECT imaging in women using an anthropomorphic phantom and receiver operating characteristics (ROC) methodology. Breast attenuation causes artifacts in reconstructed images and may increase the difficulty of diagnosis of myocardial perfusion imaging in women. The null hypothesis tested using the ROC study was that nonuniform AC does not change the lesion detectability in myocardial perfusion SPECT imaging in women. The authors used a filtered backprojection (FBP) reconstruction algorithm and Chang's single iteration method for AC. In conclusion, with the proposed myocardial defect model nuclear medicine physicians demonstrated no significant difference for the detection of the anterior wall defect; however, a greater accuracy for the detection of the inferior wall defect was observed without nonuniform AC than with it. Medical physicists did not demonstrate any statistically significant difference in defect detection accuracy with or without nonuniform AC in the female phantom

  20. Second generation anthropomorphic physical phantom for mammography and DBT: Incorporating voxelized 3D printing and inkjet printing of iodinated lesion inserts

    Science.gov (United States)

    Sikaria, Dhiraj; Musinsky, Stephanie; Sturgeon, Gregory M.; Solomon, Justin; Diao, Andrew; Gehm, Michael E.; Samei, Ehsan; Glick, Stephen J.; Lo, Joseph Y.

    2016-03-01

    Physical phantoms are needed for the evaluation and optimization of new digital breast tomosynthesis (DBT) systems. Previously, we developed an anthropomorphic phantom based on human subject breast CT data and fabricated using commercial 3D printing. We now present three key advancements: voxelized 3D printing, photopolymer material doping, and 2D inkjet printing of lesion inserts. First, we bypassed the printer's control software in order to print in voxelized form instead of conventional STL surfaces, thus improving resolution and allowing dithering to mix the two photopolymer materials into arbitrary proportions. We demonstrated ability to print details as small as 150μm, and dithering to combine VeroWhitePlus and TangoPlus in 10% increments. Second, to address the limited attenuation difference among commercial photopolymers, we evaluated a beta sample from Stratasys with increased TiO2 doping concentration up to 2.5%, which corresponded to 98% breast density. By spanning 36% to 98% breast density, this doubles our previous contrast. Third, using inkjet printers modified to print with iopamidol, we created 2D lesion patterns on paper that can be sandwiched into the phantom. Inkjet printing has advantages of being inexpensive and easy, and more contrast can be delivered through overprinting. Printing resolution was maintained at 210 μm horizontally and 330 μm vertically even after 10 overprints. Contrast increased linearly with overprinting at 0.7% per overprint. Together, these three new features provide the basis for creating a new anthropomorphic physical breast phantom with improved resolution and contrast, as well as the ability to insert 2D lesions for task-based assessment of performance.

  1. Assessment of uncertainties in the lung activity measurement of low-energy photon emitters using Monte Carlo simulation of ICRP male thorax voxel phantom

    International Nuclear Information System (INIS)

    Assessment of intake due to long-lived actinides by inhalation pathway is carried out by lung monitoring of the radiation workers inside totally shielded steel room using sensitive detection systems such as Phoswich and an array of HPGe detectors. In this paper, uncertainties in the lung activity estimation due to positional errors, chest wall thickness (CWT) and detector background variation are evaluated. First, calibration factors (CFs) of Phoswich and an array of three HPGe detectors are estimated by incorporating ICRP male thorax voxel phantom and detectors in Monte Carlo code 'FLUKA'. CFs are estimated for the uniform source distribution in lungs of the phantom for various photon energies. The variation in the CFs for positional errors of ±0.5, 1 and 1.5 cm in horizontal and vertical direction along the chest are studied. The positional errors are also evaluated by re-sizing the voxel phantom. Combined uncertainties are estimated at different energies using the uncertainties due to CWT, detector positioning, detector background variation of an uncontaminated adult person and counting statistics in the form of scattering factors (SFs). SFs are found to decrease with increase in energy. With HPGe array, highest SF of 1.84 is found at 18 keV. It reduces to 1.36 at 238 keV. (authors)

  2. Effect of imaging parameters of spiral CT scanning on image quality for the dental implants. Visual evaluation using a semi-anthropomorphic mandible phantom

    International Nuclear Information System (INIS)

    The purpose of this study was to evaluate the effect of parameters of spiral CT scanning on the image quality required for the planning of dental implants operations. A semi-anthropomorphic mandible phantom which has artificial mandibular canals and teeth roots was used as a standard object for imaging. Spiral CT scans for the phantom settled in water phantom with diameters of 20 and 16 cm were performed. Visibility of the artificial mandibular canal made of a Teflon tube and gaps between tooth apex and canal in the mandibular phantom was evaluated for various combinations of the slice thickness, tables speeds, angles to the canal, and x-ray tube currents. Teeth roots were made of PVC (poly vinyl chloride). The artificial mandibular canal was clearly observed on the images of 1 mm slice thickness. At the same table speed of 2 mm /rotation, the images of thin slice (1 mm) were superior to that of thick slice (2 mm). The gap between teeth apex and canal was erroneously diagnosed on the images with table speeds of 3 mm/rotation. Horizontal scanning in parallel to the canal result in poor image quality for observation of mandibular canals because of the partial volume effect. A relatively high x-ray tube current (125 mA) at thin slice (1 mm) scanning was required for scanning the mandibular phantom in 20 cm water vessel. Spiral scanning with slice thickness of 1 mm and table speeds of 1 of 2 mm/rotation seemed to be suitable for dental implants. The result of this study suggested that diagnosis from two independent spiral scans with a different angle to the object was more accurate and more efficient than single spiral scanning. (author)

  3. SU-E-I-74: Image-Matching Technique of Computed Tomography Images for Personal Identification: A Preliminary Study Using Anthropomorphic Chest Phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Matsunobu, Y; Shiotsuki, K [Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, Fukuoka (Japan); Morishita, J [Department of Health Sciences, Faculty of Medical Sciences, Kyushu University, Fukuoka, JP (Japan)

    2015-06-15

    Purpose: Fingerprints, dental impressions, and DNA are used to identify unidentified bodies in forensic medicine. Cranial Computed tomography (CT) images and/or dental radiographs are also used for identification. Radiological identification is important, particularly in the absence of comparative fingerprints, dental impressions, and DNA samples. The development of an automated radiological identification system for unidentified bodies is desirable. We investigated the potential usefulness of bone structure for matching chest CT images. Methods: CT images of three anthropomorphic chest phantoms were obtained on different days in various settings. One of the phantoms was assumed to be an unidentified body. The bone image and the bone image with soft tissue (BST image) were extracted from the CT images. To examine the usefulness of the bone image and/or the BST image, the similarities between the two-dimensional (2D) or threedimensional (3D) images of the same and different phantoms were evaluated in terms of the normalized cross-correlation value (NCC). Results: For the 2D and 3D BST images, the NCCs obtained from the same phantom assumed to be an unidentified body (2D, 0.99; 3D, 0.93) were higher than those for the different phantoms (2D, 0.95 and 0.91; 3D, 0.89 and 0.80). The NCCs for the same phantom (2D, 0.95; 3D, 0.88) were greater compared to those of the different phantoms (2D, 0.61 and 0.25; 3D, 0.23 and 0.10) for the bone image. The difference in the NCCs between the same and different phantoms tended to be larger for the bone images than for the BST images. These findings suggest that the image-matching technique is more useful when utilizing the bone image than when utilizing the BST image to identify different people. Conclusion: This preliminary study indicated that evaluating the similarity of bone structure in 2D and 3D images is potentially useful for identifying of an unidentified body.

  4. SU-E-I-74: Image-Matching Technique of Computed Tomography Images for Personal Identification: A Preliminary Study Using Anthropomorphic Chest Phantoms

    International Nuclear Information System (INIS)

    Purpose: Fingerprints, dental impressions, and DNA are used to identify unidentified bodies in forensic medicine. Cranial Computed tomography (CT) images and/or dental radiographs are also used for identification. Radiological identification is important, particularly in the absence of comparative fingerprints, dental impressions, and DNA samples. The development of an automated radiological identification system for unidentified bodies is desirable. We investigated the potential usefulness of bone structure for matching chest CT images. Methods: CT images of three anthropomorphic chest phantoms were obtained on different days in various settings. One of the phantoms was assumed to be an unidentified body. The bone image and the bone image with soft tissue (BST image) were extracted from the CT images. To examine the usefulness of the bone image and/or the BST image, the similarities between the two-dimensional (2D) or threedimensional (3D) images of the same and different phantoms were evaluated in terms of the normalized cross-correlation value (NCC). Results: For the 2D and 3D BST images, the NCCs obtained from the same phantom assumed to be an unidentified body (2D, 0.99; 3D, 0.93) were higher than those for the different phantoms (2D, 0.95 and 0.91; 3D, 0.89 and 0.80). The NCCs for the same phantom (2D, 0.95; 3D, 0.88) were greater compared to those of the different phantoms (2D, 0.61 and 0.25; 3D, 0.23 and 0.10) for the bone image. The difference in the NCCs between the same and different phantoms tended to be larger for the bone images than for the BST images. These findings suggest that the image-matching technique is more useful when utilizing the bone image than when utilizing the BST image to identify different people. Conclusion: This preliminary study indicated that evaluating the similarity of bone structure in 2D and 3D images is potentially useful for identifying of an unidentified body

  5. Effects of exposure equalization on image signal-to-noise ratios in digital mammography: A simulation study with an anthropomorphic breast phantom

    International Nuclear Information System (INIS)

    Purpose: The scan equalization digital mammography (SEDM) technique combines slot scanning and exposure equalization to improve low-contrast performance of digital mammography in dense tissue areas. In this study, full-field digital mammography (FFDM) images of an anthropomorphic breast phantom acquired with an anti-scatter grid at various exposure levels were superimposed to simulate SEDM images and investigate the improvement of low-contrast performance as quantified by primary signal-to-noise ratios (PSNRs). Methods: We imaged an anthropomorphic breast phantom (Gammex 169 ''Rachel,'' Gammex RMI, Middleton, WI) at various exposure levels using a FFDM system (Senographe 2000D, GE Medical Systems, Milwaukee, WI). The exposure equalization factors were computed based on a standard FFDM image acquired in the automatic exposure control (AEC) mode. The equalized image was simulated and constructed by superimposing a selected set of FFDM images acquired at 2, 1, 1/2, 1/4, 1/8, 1/16, and 1/32 times of exposure levels to the standard AEC timed technique (125 mAs) using the equalization factors computed for each region. Finally, the equalized image was renormalized regionally with the exposure equalization factors to result in an appearance similar to that with standard digital mammography. Two sets of FFDM images were acquired to allow for two identically, but independently, formed equalized images to be subtracted from each other to estimate the noise levels. Similarly, two identically but independently acquired standard FFDM images were subtracted to estimate the noise levels. Corrections were applied to remove the excess system noise accumulated during image superimposition in forming the equalized image. PSNRs over the compressed area of breast phantom were computed and used to quantitatively study the effects of exposure equalization on low-contrast performance in digital mammography. Results: We found that the highest achievable PSNR improvement factor was 1.89 for

  6. A dynamic thorax phantom for the assessment of cardiac and respiratory motion correction in PET/MRI: A preliminary evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Fieseler, Michael, E-mail: michael.fieseler@uni-muenster.de [European Institute for Molecular Imaging, University of Münster, Mendelstrasse 11, 48149 Münster (Germany); Department of Computer Science, University of Münster, Einsteinstrasse 62, 48149 Münster (Germany); Kugel, Harald [Department of Clinical Radiology, University Hospital of Münster, Albert-Schweitzer-Campus 1, 48149 Münster (Germany); Gigengack, Fabian [European Institute for Molecular Imaging, University of Münster, Mendelstrasse 11, 48149 Münster (Germany); Department of Computer Science, University of Münster, Einsteinstrasse 62, 48149 Münster (Germany); Kösters, Thomas; Büther, Florian [European Institute for Molecular Imaging, University of Münster, Mendelstrasse 11, 48149 Münster (Germany); Quick, Harald H. [Institute of Medical Physics, University of Erlangen-Nürnberg, Henkestrasse 91, 91052 Erlangen (Germany); Faber, Cornelius [Department of Clinical Radiology, University Hospital of Münster, Albert-Schweitzer-Campus 1, 48149 Münster (Germany); Jiang, Xiaoyi [Department of Computer Science, University of Münster, Einsteinstrasse 62, 48149 Münster (Germany); Schäfers, Klaus P. [European Institute for Molecular Imaging, University of Münster, Mendelstrasse 11, 48149 Münster (Germany)

    2013-02-21

    Respiratory and cardiac motion are a known source of image degradation and quantification impairment in positron emission tomography (PET). In this study we use near-realistic PET/MRI data acquired using a custom-built human torso phantom capable of simulating respiratory and cardiac motion. We demonstrate that a significant reduction in motion-induced artifacts in PET data is possible using MR-derived motion estimates.

  7. A dynamic thorax phantom for the assessment of cardiac and respiratory motion correction in PET/MRI: A preliminary evaluation

    Science.gov (United States)

    Fieseler, Michael; Kugel, Harald; Gigengack, Fabian; Kösters, Thomas; Büther, Florian; Quick, Harald H.; Faber, Cornelius; Jiang, Xiaoyi; Schäfers, Klaus P.

    2013-02-01

    Respiratory and cardiac motion are a known source of image degradation and quantification impairment in positron emission tomography (PET). In this study we use near-realistic PET/MRI data acquired using a custom-built human torso phantom capable of simulating respiratory and cardiac motion. We demonstrate that a significant reduction in motion-induced artifacts in PET data is possible using MR-derived motion estimates.

  8. Study on motion artifacts in coronary arteries with an anthropomorphic moving heart phantom on an ECG-gated multidetector computed tomography unit

    International Nuclear Information System (INIS)

    Acquisition time plays a key role in the quality of cardiac multidetector computed tomography (MDCT) and is directly related to the rotation time of the scanner. The purpose of this study is to examine the influence of heart rate and a multisector reconstruction algorithm on the image quality of coronary arteries of an anthropomorphic adjustable moving heart phantom on an ECG-gated MDCT unit. The heart phantom and a coronary artery phantom were used on a MDCT unit with a rotation time of 500 ms. The movement of the heart was determined by analysis of the images taken at different phases. The results indicate that the movement of the coronary arteries on the heart phantom is comparable to that in a clinical setting. The influence of the heart rate on image quality and artifacts was determined by analysis of several heart rates between 40 and 80 bpm where the movement of the heart was synchronized using a retrospective ECG-gated acquisition protocol. The resulting reformatted volume rendering images of the moving heart and the coronary arteries were qualitatively compared as a result of the heart rate. The evaluation was performed on three independent series by two independent radiologists for the image quality of the coronary arteries and the presence of artifacts. The evaluation shows that at heart rates above 50 bpm the influence of motion artifacts in the coronary arteries becomes apparent. In addition the influence of a dedicated multisector reconstruction technique on image quality was determined. The results show that the image quality of the coronary arteries is not only related to the heart rate and that the influence of the multisector reconstruction technique becomes significant above 70 bpm. Therefore, this study proves that from the actual acquisition time per heart cycle one cannot determine an actual acquisition time, but only a mathematical acquisition time. (orig.)

  9. Magnetic resonance imaging properties of multimodality anthropomorphic silicone rubber phantoms for validating surgical robots and image guided therapy systems

    Science.gov (United States)

    Cheung, Carling L.; Looi, Thomas; Drake, James; Kim, Peter C. W.

    2012-02-01

    The development of image guided robotic and mechatronic platforms for medical applications requires a phantom model for initial testing. Finding an appropriate phantom becomes challenging when the targeted patient population is pediatrics, particularly infants, neonates or fetuses. Our group is currently developing a pediatricsized surgical robot that operates under fused MRI and laparoscopic video guidance. To support this work, we describe a method for designing and manufacturing silicone rubber organ phantoms for the purpose of testing the robotics and the image fusion system. A surface model of the organ is obtained and converted into a mold that is then rapid-prototyped using a 3D printer. The mold is filled with a solution containing a particular ratio of silicone rubber to slacker additive to achieve a specific set of tactile and imaging characteristics in the phantom. The expected MRI relaxation times of different ratios of silicone rubber to slacker additive are experimentally quantified so that the imaging properties of the phantom can be matched to those of the organ that it represents. Samples of silicone rubber and slacker additive mixed in ratios ranging from 1:0 to 1:1.5 were prepared and scanned using inversion recovery and spin echo sequences with varying TI and TE, respectively, in order to fit curves to calculate the expected T1 and T2 relaxation times of each ratio. A set of infantsized abdominal organs was prepared, which were successfully sutured by the robot and imaged using different modalities.

  10. Small lesions detectability with the biograph 16 Hi-Rez PET/CT scanner and fast imaging protocols. Performance evaluation using an anthropomorphic thoracic phantom and ROC analyses

    International Nuclear Information System (INIS)

    The purpose of this study was to evaluate the impact on lesion detectability of fast imaging protocols using 18F- fluorodeoxyglucose (FDG) and a 3-dimensional lutetium oxyorthosilicate (LSO)-based positron emission tomography (PET)/CT scanner. An anthropomorphic thoracic phantom was used simulating the anatomical structures of radioactivity distribution for the upper torso of an underweight patient. Irregularly shaped targets of small dimensions, the zeolites, were located inside the phantom in an unpredictable position for the observers. Target-to background ratios and target dimensions were selected in order to sample the range of detectability. Repeated imaging was performed to acquire PET images with varying emission scan duration (ESD) of 1, 2, 3 and 4 min/bed and background activity concentrations of 10, 5 and 3 kBq/mL in the torso cavity. Three observers ranked the targets and a receiver operating characteristic analysis was performed for each acquisition protocol. Detection performances improved when passing from a short (ESD=1 min) protocol to longer (ESD ≥2 min) protocols. This improvement was established with adequate statistical significance. Short image acquisition times of 1 min/bed using 18F-FDG and the specific scanner model considered in the study lead to reduced lesion detectability and should be avoided also in underweight patients. (author)

  11. Typical exposure parameters, organ doses and effective doses for endovascular aortic aneurysm repair: Comparison of Monte Carlo simulations and direct measurements with an anthropomorphic phantom

    International Nuclear Information System (INIS)

    Radiation exposure of patients during endovascular aneurysm repair (EVAR) procedures ranks in the upper sector of medical exposure. Thus, estimation of radiation doses achieved during EVAR is of great importance. Organ doses (OD) and effective doses (ED) administered to 17 patients receiving EVAR were determined (1) from the exposure parameters by performing Monte Carlo simulations in mathematical phantoms and (2) by measurements with thermoluminescent dosimeters in a physical anthropomorphic phantom. The mean fluoroscopy time was 26 min, the mean dose area product was 24995 cGy cm2. The mean ED was 34.8 mSv, ODs up to 626 mSv were found. Whereas digital subtraction angiographies (DSA) and fluoroscopies each contributed about 50 % to the cumulative ED, the ED rates of DSAs were found to be ten times higher than those of fluoroscopies. Doubling of the field size caused an ED rate enhancement up to a factor of 3. EVAR procedures cause high radiation exposure levels that exceed the values published thus far. As a consequence, (1) DSAs should be only performed when necessary and with a low image rate, (2) fluoroscopies should be kept as short as possible, and (3) field sizes should be minimized. (orig.)

  12. Typical exposure parameters, organ doses and effective doses for endovascular aortic aneurysm repair: Comparison of Monte Carlo simulations and direct measurements with an anthropomorphic phantom

    Energy Technology Data Exchange (ETDEWEB)

    Foerth, Monika; Treitl, Karla Maria; Treitl, Marcus [Ludwig Maximilians University of Munich, Institute for Clinical Radiology, Munich (Germany); Seidenbusch, Michael C. [Ludwig Maximilians University of Munich, Institute for Clinical Radiology, Munich (Germany); Clinical Centre of the Ludwig Maximilian University of Munich, Institute for Clinical Radiology, Munich (Germany); Sadeghi-Azandaryani, Mojtaba [Clinical Centre of the County of Erding, Department of Vascular Surgery, Erding (Germany); Lechel, Ursula [Federal Office for Radiation Protection, Department of Medical and Occupational Radiation Protection, Oberschleissheim (Germany)

    2015-09-15

    Radiation exposure of patients during endovascular aneurysm repair (EVAR) procedures ranks in the upper sector of medical exposure. Thus, estimation of radiation doses achieved during EVAR is of great importance. Organ doses (OD) and effective doses (ED) administered to 17 patients receiving EVAR were determined (1) from the exposure parameters by performing Monte Carlo simulations in mathematical phantoms and (2) by measurements with thermoluminescent dosimeters in a physical anthropomorphic phantom. The mean fluoroscopy time was 26 min, the mean dose area product was 24995 cGy cm2. The mean ED was 34.8 mSv, ODs up to 626 mSv were found. Whereas digital subtraction angiographies (DSA) and fluoroscopies each contributed about 50 % to the cumulative ED, the ED rates of DSAs were found to be ten times higher than those of fluoroscopies. Doubling of the field size caused an ED rate enhancement up to a factor of 3. EVAR procedures cause high radiation exposure levels that exceed the values published thus far. As a consequence, (1) DSAs should be only performed when necessary and with a low image rate, (2) fluoroscopies should be kept as short as possible, and (3) field sizes should be minimized. (orig.)

  13. Effective dose estimation for pediatric voiding cystourethrography using an anthropomorphic phantom set and metal oxide semiconductor field-effect transistor (MOSFET) technology

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ryan [McMaster University, Department of Medical and Health Physics, Hamilton (Canada); Thomas, Karen E.; Falkiner, Michelle; Gordon, Christopher L. [Hospital for Sick Children, Department of Diagnostic Imaging, Toronto (Canada); Connolly, Bairbre L. [Hospital for Sick Children, Image-Guided Therapy, Department of Diagnostic Imaging, Toronto (Canada)

    2009-06-15

    The risks associated with radiation exposure are higher in children than in adults. Therefore the use of fluoroscopy in common pediatric examinations such as voiding cystourethrography (VCUG) requires accurate determination of the associated effective dose. To estimate effective dose for VCUG examinations performed in children younger than 10 years using anthropomorphic phantoms and metal oxide semiconductor field-effect transistor (MOSFET) dosimeters. MOSFETs were placed within four phantoms representing children {<=}10 years old, at locations corresponding to radiosensitive organs, and exposed to a mock VCUG (5 min of fluoroscopy, 50 spot exposures) to minimize measurement error. Effective dose was measured and scaled to a standardized clinical VCUG (1 min fluoroscopy, 5 spot exposures) determined from patient logs. Monte Carlo simulations were performed to assess the accuracy of the measured effective dose. The dose area product (DAP) from each VCUG was compared to the effective dose. Effective doses ranged from 0.10 to 0.55 mSv, increased with age, and were higher in girls. Fluoroscopy accounted for 88-90% of the total effective dose, and spot exposures 10-12%. MOSFET-measured and simulation-derived effective doses were comparable (T > 0.12). DAP was strongly correlated with effective dose for both genders (r {sup 2}>0.97, P < 0.0001). Effective doses for VCUG examinations performed in children {<=}10 years of age are low but not negligible. (orig.)

  14. WE-E-18A-02: Enhancement of Lung Tumor Visibility by Dual-Energy X-Ray Imaging in An Anthropomorphic Chest Phantom Study

    International Nuclear Information System (INIS)

    Purpose: Intrafractional lung tumor motion during radiotherapy can be compensated for by tracking the tumor position using x-ray imaging and adapting the treatment in real-time. However, locating the tumor with an automated template-matching algorithm is often challenging if the tumor is obscured by ribs. This study investigates the feasibility of creating dual-energy (DE) images of the chest with increased tumor visibility on an Elekta XVI system. Methods: An anthropomorphic chest phantom was imaged at two different energies. Low-energy images were obtained at 80 kVp (0.8 mAs); high-energy images at 129 kVp (0.6 mAs, additional 1.26 mm tin filter). A Geant4 Monte-Carlo framework was developed allowing simulation of the x-ray tube, flat-panel detector and phantom in order to optimize the beam energies, filtration and the weighting factor used to subtract the individual images into a synthetic DE image. The weighting factor was selected to minimize the visibility of bones while maintaining a sufficient tumor visibility. We scored the bone visibility as the contrast of tumor (with bone) to tumor (without bone), and similarly of lung tissue (with bone) to lung tissue (without bone). Tumor visibility was quantified as the contrast between tumor and lung tissue (both without bone). Results: In the experimentally obtained DE image the bone visibility was reduced by 79.2% in tumor and by 96.8% in lung tissue while the overall tumor visibility only decreased by 69.5%. The Monte-Carlo simulation yielded similar results reducing the scores by 90.0%, 85.3% and only 71.9%, respectively. Conclusion: This work demonstrates the feasibility of DE imaging to enhance lung tumor detectability. In the future, we hope to further refine the Monte-Carlo simulation to more accurately predict the weighting factors which would aid real-time implementation. Furthermore, we plan to use the Monte-Carlo framework to simulate DE images of actual lung tumors. The authors would like to thank Paul

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

    Energy Technology Data Exchange (ETDEWEB)

    Mahmood, U; Erdi, Y; Wang, W [Memorial Sloan Kettering Cancer Center, NY, NY (United States)

    2014-06-01

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

  16. SU-E-I-89: Assessment of CT Radiation Dose and Image Quality for An Automated Tube Potential Selection Algorithm Using Pediatric Anthropomorphic and ACR Phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Mahmood, U; Erdi, Y; Wang, W [Memorial Sloan Kettering Cancer Center, NY, NY (United States)

    2014-06-01

    Purpose: To assess the impact of General Electrics automated tube potential algorithm, kV assist (kVa) on radiation dose and image quality, with an emphasis on optimizing protocols based on noise texture. Methods: Radiation dose was assessed by inserting optically stimulated luminescence dosimeters (OSLs) throughout the body of a pediatric anthropomorphic phantom (CIRS). The baseline protocol was: 120 kVp, 80 mA, 0.7s rotation time. Image quality was assessed by calculating the contrast to noise ratio (CNR) and noise power spectrum (NPS) from the ACR CT accreditation phantom. CNRs were calculated according to the steps described in ACR CT phantom testing document. NPS was determined by taking the 3D FFT of the uniformity section of the ACR phantom. NPS and CNR were evaluated with and without kVa and for all available adaptive iterative statistical reconstruction (ASiR) settings, ranging from 0 to 100%. Each NPS was also evaluated for its peak frequency difference (PFD) with respect to the baseline protocol. Results: For the baseline protocol, CNR was found to decrease from 0.460 ± 0.182 to 0.420 ± 0.057 when kVa was activated. When compared against the baseline protocol, the PFD at ASiR of 40% yielded a decrease in noise magnitude as realized by the increase in CNR = 0.620 ± 0.040. The liver dose decreased by 30% with kVa activation. Conclusion: Application of kVa reduces the liver dose up to 30%. However, reduction in image quality for abdominal scans occurs when using the automated tube voltage selection feature at the baseline protocol. As demonstrated by the CNR and NPS analysis, the texture and magnitude of the noise in reconstructed images at ASiR 40% was found to be the same as our baseline images. We have demonstrated that 30% dose reduction is possible when using 40% ASiR with kVa in pediatric patients.

  17. Use of an anthropomorphic hand phantom to verify the radiation intensity that is needed to modify the analog and digital radiographic quality

    International Nuclear Information System (INIS)

    The radiology is a field of medicine that is in constantly expansion and advancing. This can be noticed with the transition from analog to digital radiology systems, it is important that professionals understand image formation in both systems in order to produce radiographies with diagnostic quality. Therefore, the objective of this work is to present the importance of radiological protection by changing values of technical parameters while the quality of radiographic imaging is sustained. An anthropomorphic hand phantom was built in order to obtain radiographies, as it is necessary to respect the Brazilian regulations (Portaria 453/98) which forbids the use of radiation in patients for testing. Three analog and eight digital radiographies were obtained using fixed kVp and varying mAs. Each image was compared to the others acquired in the same location. Digital radiographies have shown that approximately 28% of change in mAs is necessary to change noise, whereas approximately 33,3% is necessary in the analog system to change density. The conclusion is that computerized systems need less x-ray intensity to modify image features and can reduce the patient radiation doses. However, more testing must be conducted in different radiologic environments to confirm the results obtained in the present study. (author)

  18. Protection of eye lens in computed tomography. Dose evaluation on an anthropomorphic phantom using thermo-luminescent dosimeters and Monte-Carlo simulations

    International Nuclear Information System (INIS)

    Purpose: the lens of an eye is a particularly radiosensitive organ. This study investigates two different materials for eye shielding during CT scanning, i.e. a commercially available bismuth protector and a newly developed material for eye shielding, comprised of an alloy of Bi/Sb/Gd/W. Materials and methods: the radiation dose during head CT scanning was measured using thermoluminescence dosimeters and an anthropomorphic Alderson-RANDO phantom. A radiation dose reduction was compared to two shielding materials and to the condition without any eye shielding. The effect of gantry angulation that excludes the eyes from beam path was also investigated. Radiation dose measurements were validated using a Monte-Carlo simulation. For this simulation we used the EGSsnr code system, and a new application CTDOSPP was developed for simulation of the computed tomography examination. Eight radiologists evaluated the diagnostic quality of the images. Results: dose measurements and Monte-Carlo simulations are in good agreement. If the eye shields are placed in the primary beam path, bismuth eye shielding and the new material reduce the dose by up to 38% and 48%, respectively. Angling the gantry causes an 88% reduction in radiation dose. All shielding materials generate beam hardening artifacts located close to the protector, but the artifacts do not spread into the brain. (orig.)

  19. Volumetric x-ray coherent scatter imaging of cancer in resected breast tissue: a Monte Carlo study using virtual anthropomorphic phantoms

    Science.gov (United States)

    Lakshmanan, Manu N.; Harrawood, Brian P.; Samei, Ehsan; Kapadia, Anuj J.

    2015-08-01

    Breast cancer patients undergoing surgery often choose to have a breast conserving surgery (BCS) instead of mastectomy for removal of only the breast tumor. If post-surgical analysis such as histological assessment of the resected tumor reveals insufficient healthy tissue margins around the cancerous tumor, the patient must undergo another surgery to remove the missed tumor tissue. Such re-excisions are reported to occur in 20%-70% of BCS patients. A real-time surgical margin assessment technique that is fast and consistently accurate could greatly reduce the number of re-excisions performed in BCS. We describe here a tumor margin assessment method based on x-ray coherent scatter computed tomography (CSCT) imaging and demonstrate its utility in surgical margin assessment using Monte Carlo simulations. A CSCT system was simulated in Geant4 and used to simulate two virtual anthropomorphic CSCT scans of phantoms resembling surgically resected tissue. The resulting images were volume-rendered and found to distinguish cancerous tumors embedded in complex distributions of adipose and fibroglandular breast tissue (as is expected in the breast). The images exhibited sufficient spatial and spectral (i.e. momentum transfer) resolution to classify the tissue in any given voxel as healthy or cancerous. ROC analysis of the classification accuracy revealed an area under the curve of up to 0.97. These results indicate that coherent scatter imaging is promising as a possible fast and accurate surgical margin assessment technique.

  20. Volumetric x-ray coherent scatter imaging of cancer in resected breast tissue: a Monte Carlo study using virtual anthropomorphic phantoms

    International Nuclear Information System (INIS)

    Breast cancer patients undergoing surgery often choose to have a breast conserving surgery (BCS) instead of mastectomy for removal of only the breast tumor. If post-surgical analysis such as histological assessment of the resected tumor reveals insufficient healthy tissue margins around the cancerous tumor, the patient must undergo another surgery to remove the missed tumor tissue. Such re-excisions are reported to occur in 20%–70% of BCS patients. A real-time surgical margin assessment technique that is fast and consistently accurate could greatly reduce the number of re-excisions performed in BCS. We describe here a tumor margin assessment method based on x-ray coherent scatter computed tomography (CSCT) imaging and demonstrate its utility in surgical margin assessment using Monte Carlo simulations. A CSCT system was simulated in Geant4 and used to simulate two virtual anthropomorphic CSCT scans of phantoms resembling surgically resected tissue. The resulting images were volume-rendered and found to distinguish cancerous tumors embedded in complex distributions of adipose and fibroglandular breast tissue (as is expected in the breast). The images exhibited sufficient spatial and spectral (i.e. momentum transfer) resolution to classify the tissue in any given voxel as healthy or cancerous. ROC analysis of the classification accuracy revealed an area under the curve of up to 0.97. These results indicate that coherent scatter imaging is promising as a possible fast and accurate surgical margin assessment technique. (paper)

  1. Effects of tube potential and scatter rejection on image quality and effective dose in digital chest X-ray examination: An anthropomorphic phantom study

    International Nuclear Information System (INIS)

    Objectives: The purpose of this study was to investigate the effects of tube potential and scatter rejection techniques on image quality of digital posteroanterior (PA) chest radiographs. Methods: An anthropomorphic phantom was imaged using a range of tube potentials (81–125 kVp) without scatter rejection, with an anti-scatter grid, and using a 10 cm air gap. Images were anonymised and randomised before being evaluated using a visual graded analysis (VGA) method. Results: The effects of tube potential on image quality were found to be negligible (p > 0.63) for the flat panel detector (FPD). Decreased image quality (p = 0.031) was noted for 125 kVp relative to 109 kVp, though no difference was noted for any of the other potentials (p > 0.398) for computed radiography (CR). Both scatter rejection techniques improved image quality (p p. Scatter rejection improved image quality, but with no difference found between techniques. The air-gap resulted in a smaller increase in effective dose than the anti-scatter grid and would be the preferred scatter rejection technique

  2. Quality assurance in RapidArc with Alderson anthropomorphic phantom using radiochromic film in comparison to MATLAB

    International Nuclear Information System (INIS)

    This paper presented the quality control for RapidArc using an Alderson human body phantom and radiochromic film as an alternative system to approve the treatment plan for brain tumor. Thus, it was comprised the dose distributions provided by the treatment planning system with those measured by the film radiochromic. The gamma index (Γ) analysis, to verify the acceptability of the dose distribution, was 95% of approved points, with the mostly non-compliance points in regions near the PTV’s edges. These non-compliance points may be associated to transmission blades aspects, because the regions near the edges present significant losses compared to the central areas. Also, MATLAB has proved an effective tool for that measurements and it can be used in quality assurance programs. (author)

  3. MO-E-17A-02: Incorporation of Contrast Medium Dynamics in Anthropomorphic Phantoms: The Advent of 5D XCAT Models

    International Nuclear Information System (INIS)

    Purpose: To develop a unique method to incorporate the dynamics of contrast-medium propagation into the anthropomorphic phantom, to generate a five-dimensional (5D) patient model for multimodality imaging studies. Methods: A compartmental model of blood circulation network within the body was embodied into an extended cardiac-torso (4D-XCAT) patient model. To do so, a computational physiologic model of the human cardiovascular system was developed which includes a series of compartments representing heart, vessels, and organs. Patient-specific cardiac output and blood volume were used as inputs influenced by the weight, height, age, and gender of the patient's model. For a given injection protocol and given XCAT model, the contrast-medium transmission within the body was described by a series of mass balance differential equations, the solutions to which provided the contrast enhancement-time curves for each organ; thereby defining the tissue materials including the contrastmedium within the XCAT model. A library of time-dependent organ materials was then defined. Each organ in each voxelized 4D-XCAT phantom was assigned to a corresponding time-varying material to create the 5D-XCAT phantom in which the fifth dimension is blood/contrast-medium within the temporal domain. Results: The model effectively predicts the time-varying concentration behavior of various contrast-medium administration in each organ for different patient models as function of patient size (weight/height) and different injection protocol factors (injection rate and pattern, iodine concentration or volume). The contrast enhanced XCAT patient models was developed based on the concentration of iodine as a function of time after injection. Conclusion: Majority of medical imaging systems take advantage of contrast-medium administration in terms of better image quality, the effect of which was ignored in previous optimization studies. The study enables a comprehensive optimization of contrast

  4. MO-E-17A-02: Incorporation of Contrast Medium Dynamics in Anthropomorphic Phantoms: The Advent of 5D XCAT Models

    Energy Technology Data Exchange (ETDEWEB)

    Sahbaee, P [NC State University, Raleigh, NC (United States); Samei, E [Duke University Medical Center, Durham, NC (United States); Segars, W [Duke University, Durham, NC (United States)

    2014-06-15

    Purpose: To develop a unique method to incorporate the dynamics of contrast-medium propagation into the anthropomorphic phantom, to generate a five-dimensional (5D) patient model for multimodality imaging studies. Methods: A compartmental model of blood circulation network within the body was embodied into an extended cardiac-torso (4D-XCAT) patient model. To do so, a computational physiologic model of the human cardiovascular system was developed which includes a series of compartments representing heart, vessels, and organs. Patient-specific cardiac output and blood volume were used as inputs influenced by the weight, height, age, and gender of the patient's model. For a given injection protocol and given XCAT model, the contrast-medium transmission within the body was described by a series of mass balance differential equations, the solutions to which provided the contrast enhancement-time curves for each organ; thereby defining the tissue materials including the contrastmedium within the XCAT model. A library of time-dependent organ materials was then defined. Each organ in each voxelized 4D-XCAT phantom was assigned to a corresponding time-varying material to create the 5D-XCAT phantom in which the fifth dimension is blood/contrast-medium within the temporal domain. Results: The model effectively predicts the time-varying concentration behavior of various contrast-medium administration in each organ for different patient models as function of patient size (weight/height) and different injection protocol factors (injection rate and pattern, iodine concentration or volume). The contrast enhanced XCAT patient models was developed based on the concentration of iodine as a function of time after injection. Conclusion: Majority of medical imaging systems take advantage of contrast-medium administration in terms of better image quality, the effect of which was ignored in previous optimization studies. The study enables a comprehensive optimization of contrast

  5. Experimental and computational development of a natural breast phantom for dosimetry studies

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, Luciana B.; Campos, Tarcisio P.R., E-mail: lucibn19@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)

    2013-07-01

    This paper describes the experimental and computational development of a natural breast phantom, anthropomorphic and anthropometric for studies in dosimetry of brachytherapy and teletherapy of breast. The natural breast phantom developed corresponding to fibroadipose breasts of women aged 30 to 50 years, presenting radiographically medium density. The experimental breast phantom was constituted of three tissue-equivalents (TE's): glandular TE, adipose TE and skin TE. These TE's were developed according to chemical composition of human breast and present radiological response to exposure. Completed the construction of experimental breast phantom this was mounted on a thorax phantom previously developed by the research group NRI/UFMG. Then the computational breast phantom was constructed by performing a computed tomography (CT) by axial slices of the chest phantom. Through the images generated by CT a computational model of voxels of the thorax phantom was developed by SISCODES computational program, being the computational breast phantom represented by the same TE's of the experimental breast phantom. The images generated by CT allowed evaluating the radiological equivalence of the tissues. The breast phantom is being used in studies of experimental dosimetry both in brachytherapy as in teletherapy of breast. Dosimetry studies by MCNP-5 code using the computational model of the phantom breast are in progress. (author)

  6. Experimental and computational development of a natural breast phantom for dosimetry studies

    International Nuclear Information System (INIS)

    This paper describes the experimental and computational development of a natural breast phantom, anthropomorphic and anthropometric for studies in dosimetry of brachytherapy and teletherapy of breast. The natural breast phantom developed corresponding to fibroadipose breasts of women aged 30 to 50 years, presenting radiographically medium density. The experimental breast phantom was constituted of three tissue-equivalents (TE's): glandular TE, adipose TE and skin TE. These TE's were developed according to chemical composition of human breast and present radiological response to exposure. Completed the construction of experimental breast phantom this was mounted on a thorax phantom previously developed by the research group NRI/UFMG. Then the computational breast phantom was constructed by performing a computed tomography (CT) by axial slices of the chest phantom. Through the images generated by CT a computational model of voxels of the thorax phantom was developed by SISCODES computational program, being the computational breast phantom represented by the same TE's of the experimental breast phantom. The images generated by CT allowed evaluating the radiological equivalence of the tissues. The breast phantom is being used in studies of experimental dosimetry both in brachytherapy as in teletherapy of breast. Dosimetry studies by MCNP-5 code using the computational model of the phantom breast are in progress. (author)

  7. Design and development of an anthropomorphic phantom equipped with detectors in order to evaluate the effective dose E at workplaces: feasibility study; Conception et developpement d'un fantome anthropomorphe equipe de detecteurs dans le but d'evaluer la dose efficace a un poste de travail: etude de faisabilite

    Energy Technology Data Exchange (ETDEWEB)

    Furstoss, Ch

    2006-11-15

    My PhD study aims to determine the feasibility to design and develop, for photon fields, an anthropomorphic phantom equipped with detectors in order to evaluate the effective dose E at workplaces. First of all, the energy losses within the organs are calculated using the M.C.N.P.X. Monte Carlo code, in order to determine the detection positions within the different organs. Then, to decrease the number of detection positions, the organ contribution to the effective dose is studied. Finally, the characteristics of the detectors to insert and the characteristics of the phantom to use are deduced. The results show that 24 or 23 detection positions, according to the wT values (publication 60 or new recommendations of the ICRP), give a E estimation with an uncertainty of {+-}15 % from 50 keV to 4 MeV. Moreover, the interest of such an instrument is underlined while comparing the E estimation by the personal dose equivalent Hp to the E estimation by the instrumented phantom when the phantom is irradiated by point sources (worker in front of a glove box for example). Last, after the detector and phantom characteristic determination, two types of detectors and one type of phantom are selected. However, for the detectors mainly, developments are necessary. Follow up this study, the characterization and the adaptation of the detectors to the project would be interesting. Furthermore, the study to mixed photon-neutrons would be required the needs of the radiological protection community. (author)

  8. Effective dose estimation for pediatric upper gastrointestinal examinations using an anthropomorphic phantom set and metal oxide semiconductor field-effect transistor (MOSFET) technology

    International Nuclear Information System (INIS)

    There is a need for updated radiation dose estimates in pediatric fluoroscopy given the routine use of new dose-saving technologies and increased radiation safety awareness in pediatric imaging. To estimate effective doses for standardized pediatric upper gastrointestinal (UGI) examinations at our institute using direct dose measurement, as well as provide dose-area product (DAP) to effective dose conversion factors to be used for the estimation of UGI effective doses for boys and girls up to 10 years of age at other centers. Metal oxide semiconductor field-effect transistor (MOSFET) dosimeters were placed within four anthropomorphic phantoms representing children ≤10 years of age and exposed to mock UGI examinations using exposures much greater than used clinically to minimize measurement error. Measured effective dose was calculated using ICRP 103 weights and scaled to our institution's standardized clinical UGI (3.6-min fluoroscopy, four spot exposures and four examination beam projections) as determined from patient logs. Results were compared to Monte Carlo simulations and related to fluoroscope-displayed DAP. Measured effective doses for standardized pediatric UGI examinations in our institute ranged from 0.35 to 0.79 mSv in girls and were 3-8% lower for boys. Simulation-derived and measured effective doses were in agreement (percentage differences 0.18). DAP-to-effective dose conversion factors ranged from 6.5 x 10-4 mSv per Gy-cm2 to 4.3 x 10-3 mSv per Gy-cm2 for girls and were similarly lower for boys. Using modern fluoroscopy equipment, the effective dose associated with the UGI examination in children ≤10 years at our institute is < 1 mSv. Estimations of effective dose associated with pediatric UGI examinations can be made for children up to the age of 10 using the DAP-normalized conversion factors provided in this study. These estimates can be further refined to reflect individual hospital examination protocols through the use of direct organ dose

  9. Effective dose estimation for pediatric upper gastrointestinal examinations using an anthropomorphic phantom set and metal oxide semiconductor field-effect transistor (MOSFET) technology

    Energy Technology Data Exchange (ETDEWEB)

    Emigh, Brent [McMaster University, Department of Medical Physics and Applied Radiation Sciences, Hamilton (Canada); Gordon, Christopher L.; Falkiner, Michelle; Thomas, Karen E. [The Hospital for Sick Children, Department of Diagnostic Imaging, Toronto (Canada); Connolly, Bairbre L. [The Hospital for Sick Children, Image-Guided Therapy, Department of Diagnostic Imaging, Toronto (Canada)

    2013-09-15

    There is a need for updated radiation dose estimates in pediatric fluoroscopy given the routine use of new dose-saving technologies and increased radiation safety awareness in pediatric imaging. To estimate effective doses for standardized pediatric upper gastrointestinal (UGI) examinations at our institute using direct dose measurement, as well as provide dose-area product (DAP) to effective dose conversion factors to be used for the estimation of UGI effective doses for boys and girls up to 10 years of age at other centers. Metal oxide semiconductor field-effect transistor (MOSFET) dosimeters were placed within four anthropomorphic phantoms representing children {<=}10 years of age and exposed to mock UGI examinations using exposures much greater than used clinically to minimize measurement error. Measured effective dose was calculated using ICRP 103 weights and scaled to our institution's standardized clinical UGI (3.6-min fluoroscopy, four spot exposures and four examination beam projections) as determined from patient logs. Results were compared to Monte Carlo simulations and related to fluoroscope-displayed DAP. Measured effective doses for standardized pediatric UGI examinations in our institute ranged from 0.35 to 0.79 mSv in girls and were 3-8% lower for boys. Simulation-derived and measured effective doses were in agreement (percentage differences <19%, T > 0.18). DAP-to-effective dose conversion factors ranged from 6.5 x 10{sup -4} mSv per Gy-cm{sup 2} to 4.3 x 10{sup -3} mSv per Gy-cm{sup 2} for girls and were similarly lower for boys. Using modern fluoroscopy equipment, the effective dose associated with the UGI examination in children {<=}10 years at our institute is < 1 mSv. Estimations of effective dose associated with pediatric UGI examinations can be made for children up to the age of 10 using the DAP-normalized conversion factors provided in this study. These estimates can be further refined to reflect individual hospital examination

  10. Initial implementation of the conversion from the energy-subtracted CT number to electron density in tissue inhomogeneity corrections: An anthropomorphic phantom study of radiotherapy treatment planning

    Energy Technology Data Exchange (ETDEWEB)

    Tsukihara, Masayoshi [Division of Radiological Technology, Graduate School of Health Sciences, Niigata University, Niigata 951-8518 (Japan); Noto, Yoshiyuki [Department of Radiology, Niigata University Medical and Dental Hospital, Niigata 951-8520 (Japan); Sasamoto, Ryuta; Hayakawa, Takahide; Saito, Masatoshi, E-mail: masaito@clg.niigata-u.ac.jp [Department of Radiological Technology, School of Health Sciences, Faculty of Medicine, Niigata University, Niigata 951-8518 (Japan)

    2015-03-15

    Purpose: To achieve accurate tissue inhomogeneity corrections in radiotherapy treatment planning, the authors had previously proposed a novel conversion of the energy-subtracted computed tomography (CT) number to an electron density (ΔHU–ρ{sub e} conversion), which provides a single linear relationship between ΔHU and ρ{sub e} over a wide range of ρ{sub e}. The purpose of this study is to present an initial implementation of the ΔHU–ρ{sub e} conversion method for a treatment planning system (TPS). In this paper, two example radiotherapy plans are used to evaluate the reliability of dose calculations in the ΔHU–ρ{sub e} conversion method. Methods: CT images were acquired using a clinical dual-source CT (DSCT) scanner operated in the dual-energy mode with two tube potential pairs and an additional tin (Sn) filter for the high-kV tube (80–140 kV/Sn and 100–140 kV/Sn). Single-energy CT using the same DSCT scanner was also performed at 120 kV to compare the ΔHU–ρ{sub e} conversion method with a conventional conversion from a CT number to ρ{sub e} (Hounsfield units, HU–ρ{sub e} conversion). Lookup tables for ρ{sub e} calibration were obtained from the CT image acquisitions for tissue substitutes in an electron density phantom (EDP). To investigate the beam-hardening effect on dosimetric uncertainties, two EDPs with different sizes (a body EDP and a head EDP) were used for the ρ{sub e} calibration. Each acquired lookup table was applied to two radiotherapy plans designed using the XiO TPS with the superposition algorithm for an anthropomorphic phantom. The first radiotherapy plan was for an oral cavity tumor and the second was for a lung tumor. Results: In both treatment plans, the performance of the ΔHU–ρ{sub e} conversion was superior to that of the conventional HU–ρ{sub e} conversion in terms of the reliability of dose calculations. Especially, for the oral tumor plan, which dealt with dentition and bony structures, treatment

  11. Advances in development of young-pediatric anthropometric and anthropomorphic head and neck phantoms for dosimetry; Avancos no desenvolvimento de fantomas antropomorfico e antropometrico de cabeca e pescoco infanto-juvenil para dosimetria

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Larissa; Campos, Tarcisio P.R. [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Programa de Pos-graduacao em Ciencias e Tecnicas Nucleares]. E-mail: thompson@nuclear.ufmg.br; campos@nuclear.ufmg.br

    2005-07-01

    The neck malign cancer in pediatric population differs significantly than adult cancer. The pediatric primary malign tumors result in the neck and head fence 5% . The malign cervical tumors, generally, are rabdomyossarcoms and lymphomas. The least frequent malign cancer includes metastasis, scammous cells and thyroid cancer. The larynx cancer treatment is surgery, preferentially. However, lesions with little infiltration, that do not compromise the vocals cords mobile, do not infiltrate cartilage, and do not compromise neither the anterior comissure neither the arytenoid, can be controlled with exclusive radiotherapy. The traditional dose for sub-clinical disease in larynx cancer, neck and head region, has been 50 to 60 Gy to standard fraction of 2 Gy/day, five times for week. When the treatment is consummated with exclusive radiotherapy in primary tumor. The dose must be higher, diversifying from 66 (for small tumors T1) to 70 Gy (for higher tumors, that T2 or T3). Phantoms are simulators utilized for dose prediction in patient simulating radiation interactions with matter. Also it is applied for radio diagnosis equipment calibration and quality control of medical image. Many kind of phantoms are developed, handmade and commercialized, with matters and forms most varied, holding distinct purpose, in senses of establishing double check parameters for reducing planning and calibration errors. This study addresses the development of a object for simulating young-pediatric anthropometric and anthropomorphic head and neck, called phantom, for dosimetric studies. The methodology will be based on the preparation of a phantom respecting the anatomic standards and its tissue equivalent composition. The hope is that phantom can be used in the scientific researches of radiation protocols applied to young-pediatric patient. (author)

  12. TH-A-19A-03: Impact of Proton Dose Calculation Method On Delivered Dose to Lung Tumors: Experiments in Thorax Phantom and Planning Study in Patient Cohort

    Energy Technology Data Exchange (ETDEWEB)

    Grassberger, C; Daartz, J; Dowdell, S; Ruggieri, T; Sharp, G; Paganetti, H [Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States)

    2014-06-15

    Purpose: Evaluate Monte Carlo (MC) dose calculation and the prediction of the treatment planning system (TPS) in a lung phantom and compare them in a cohort of 20 lung patients treated with protons. Methods: A 2-dimensional array of ionization chambers was used to evaluate the dose across the target in a lung phantom. 20 lung cancer patients on clinical trials were re-simulated using a validated Monte Carlo toolkit (TOPAS) and compared to the TPS. Results: MC increases dose calculation accuracy in lung compared to the clinical TPS significantly and predicts the dose to the target in the phantom within ±2%: the average difference between measured and predicted dose in a plane through the center of the target is 5.6% for the TPS and 1.6% for MC. MC recalculations in patients show a mean dose to the clinical target volume on average 3.4% lower than the TPS, exceeding 5% for small fields. The lower dose correlates significantly with aperture size and the distance of the tumor to the chest wall (Spearman's p=0.0002/0.004). For large tumors MC also predicts consistently higher V{sub 5} and V{sub 10} to the normal lung, due to a wider lateral penumbra, which was also observed experimentally. Critical structures located distal to the target can show large deviations, though this effect is very patient-specific. Conclusion: Advanced dose calculation techniques, such as MC, would improve treatment quality in proton therapy for lung cancer by avoiding systematic overestimation of target dose and underestimation of dose to normal lung. This would increase the accuracy of the relationships between dose and effect, concerning tumor control as well as normal tissue toxicity. As the role of proton therapy in the treatment of lung cancer continues to be evaluated in clinical trials, this is of ever-increasing importance. This work was supported by National Cancer Institute Grant R01CA111590.

  13. TH-A-19A-03: Impact of Proton Dose Calculation Method On Delivered Dose to Lung Tumors: Experiments in Thorax Phantom and Planning Study in Patient Cohort

    International Nuclear Information System (INIS)

    Purpose: Evaluate Monte Carlo (MC) dose calculation and the prediction of the treatment planning system (TPS) in a lung phantom and compare them in a cohort of 20 lung patients treated with protons. Methods: A 2-dimensional array of ionization chambers was used to evaluate the dose across the target in a lung phantom. 20 lung cancer patients on clinical trials were re-simulated using a validated Monte Carlo toolkit (TOPAS) and compared to the TPS. Results: MC increases dose calculation accuracy in lung compared to the clinical TPS significantly and predicts the dose to the target in the phantom within ±2%: the average difference between measured and predicted dose in a plane through the center of the target is 5.6% for the TPS and 1.6% for MC. MC recalculations in patients show a mean dose to the clinical target volume on average 3.4% lower than the TPS, exceeding 5% for small fields. The lower dose correlates significantly with aperture size and the distance of the tumor to the chest wall (Spearman's p=0.0002/0.004). For large tumors MC also predicts consistently higher V5 and V10 to the normal lung, due to a wider lateral penumbra, which was also observed experimentally. Critical structures located distal to the target can show large deviations, though this effect is very patient-specific. Conclusion: Advanced dose calculation techniques, such as MC, would improve treatment quality in proton therapy for lung cancer by avoiding systematic overestimation of target dose and underestimation of dose to normal lung. This would increase the accuracy of the relationships between dose and effect, concerning tumor control as well as normal tissue toxicity. As the role of proton therapy in the treatment of lung cancer continues to be evaluated in clinical trials, this is of ever-increasing importance. This work was supported by National Cancer Institute Grant R01CA111590

  14. Dose evaluation in occupationally exposed workers through dosimeters ring and wrist type with an anthropomorphic phantom; Evaluacion de la dosis en trabajadores ocupacionalmente expuestos a traves de dosimetros tipo anillo y de muneca con un fantoma antropomorfico

    Energy Technology Data Exchange (ETDEWEB)

    Palma, R.; Gastelo, E. [Univesidad Nacional Pedro Ruiz Gallo, Huamachuco, Lambayeque (Peru); Paucar, R.; Tolentino, D.; Herrera, J. [Complejo Hospitalario San Pablo, Lima (Peru); Armas, D., E-mail: fispalma@hotmail.com [Consorcio Proxtronics del Pacifico S. A. C., Cal. Manuela Estacio Mza. D1-2 Lote 13, San Miguel, Lima (Peru)

    2014-08-15

    In the Nuclear Medicine service of the Clinica San Pablo (Peru), the occupationally exposed workers carried out the preparation and administration of radiopharmaceuticals to patients, so it is vital to measure the equivalent dose to the hands during the procedures in order to optimize the exposure to the ionizing radiation and execute the Radiological Safety Regulation (D.S. No. 009-97-Em) and the standard IR 002.2012 of radiation protection and safety in nuclear medicine. In this paper was designed and built a hand anthropomorphic phantom made of paraffin following the description given for the standard man, later were placed dosimeters ring and wrist type UD-807 model, Panasonic brand. Then we proceeded to irradiate using vial containers of Tc-99 and I-131. The obtained results showed the difference between the equivalent dose obtained among the ring and wrist dosimeter also getting a dose of 153 mSv /year when working with {sup 99m}Tc and of 61 mSv /year when working with iodine-131. Was also demonstrated that the ring dosimeter shows the average dose received in the hand with less dispersion. It was found that under the national regulation on Requirements of Radiation Protection and Nuclear Safety in Medicine article 63, indicates that higher doses of 150 mSv /year the occupationally exposed workers should have hand dosimetry. Finally the individual dose limit of 500 mSv /year in extremities can be overcome if adequate radiation protection standards do not apply. (author)

  15. Comparison of accuracy and time-efficiency of CT colonography between conventional and panoramic 3D interpretation methods: An anthropomorphic phantom study

    International Nuclear Information System (INIS)

    Purpose: To retrospectively compare the conventional three-dimensional (3D) interpretation method with the panoramic 3D method with regard to accuracy and time-efficiency in the detection of colonic polyps, using pig colonic phantoms as the standard of reference. Materials and methods: One-hundred and sixty-two polyps were created in 18 pig colonic phantoms. CT colonography was performed with a 64-row detector CT scanner. Two-week interval reviews for the CTC image dataset with both the conventional and the panoramic 3D interpretation method were independently performed by three radiologists. The sensitivities of both methods were compared with the McNemar test. The mean interpretation time for each interpretation method was also assessed and compared with the Wilcoxon signed-rank test. Results: Compared with the conventional 3D method (0.96 for reader 1, 0.89 for reader 2, and 0.97 for reader 3), the panoramic method revealed comparable sensitivities (0.91 for reader 1, 0.86 for reader 2, and 0.93 for reader 3) (p > 0.05). Interpretation time was significantly shorter with the panoramic method (115.1 ± 32.7 s for reader 1, 229.7 ± 72.2 s for reader 2, and 282.6 ± 113.7 s for reader 3) than with the conventional method (218.9 ± 59.9 s for reader 1, 379.4 ± 117.0 s for reader 2, and 458.7 ± 149.4 s for reader 3) for all readers (p < 0.05). Conclusion: Compared with the conventional 3D interpretation method, the panoramic 3D interpretation method shows improved time-efficiency and comparable sensitivity in the detection of colonic polyps.

  16. SU-E-J-210: Characterizing Tissue Equivalent Materials for the Development of a Dual MRI-CT Heterogeneous Anthropomorphic Phantom Designed Specifically for MRI Guided Radiotherapy Systems

    Energy Technology Data Exchange (ETDEWEB)

    Steinmann, A; Stafford, R; Yung, J; Followill, D [UT MD Anderson Cancer Center, Houston, TX (United States)

    2015-06-15

    Purpose: MRI guided radiotherapy (MRIgRT) is an emerging technology which will eventually require a proficient quality auditing system. Due to different principles in which MR and CT acquire images, there is a need for a multi-imaging-modality, end-to-end QA phantom for MRIgRT. The purpose of this study is to identify lung, soft tissue, and tumor equivalent substitutes that share similar human-like CT and MR properties (i.e. Hounsfield units and relaxation times). Methods: Materials of interested such as common CT QA phantom materials, and other proprietary gels/silicones from Polytek, SmoothOn, and CompositeOne were first scanned on a GE 1.5T Signa HDxT MR. Materials that could be seen on both T1-weighted and T2-weighted images were then scanned on a GE Lightspeed RT16 CT simulator and a GE Discovery 750HD CT scanner and their HU values were then measured. The materials with matching HU values of lung (−500 to −700HU), muscle (+40HU) and soft tissue (+100 to +300HU) were further scanned on GE 1.5T Signa HDx to measure their T1 and T2 relaxation times from varying parameters of TI and TE. Results: Materials that could be visualized on T1-weighted and T2-weighted images from a 1.5T MR unit and had an appropriate average CT number, −650, −685, 46,169, and 168 HUs were: compressed cork saturated with water, Polytek Platsil™ Gel-00 combined with mini styrofoam balls, radiotherapy bolus material, SmoothOn Dragon-Skin™ and SmoothOn Ecoflex™, respectively. Conclusion: Post processing analysis is currently being performed to accurately map T1 and T2 values for each material tested. From previous MR visualization and CT examinations it is expected that Dragon-Skin™, Ecoflex™ and bolus will have values consistent with tissue and tumor substitutes. We also expect compressed cork statured with water, and Polytek™-styrofoam combination to have approximate T1 and T2 values suitable for lung-equivalent materials.

  17. SU-E-J-210: Characterizing Tissue Equivalent Materials for the Development of a Dual MRI-CT Heterogeneous Anthropomorphic Phantom Designed Specifically for MRI Guided Radiotherapy Systems

    International Nuclear Information System (INIS)

    Purpose: MRI guided radiotherapy (MRIgRT) is an emerging technology which will eventually require a proficient quality auditing system. Due to different principles in which MR and CT acquire images, there is a need for a multi-imaging-modality, end-to-end QA phantom for MRIgRT. The purpose of this study is to identify lung, soft tissue, and tumor equivalent substitutes that share similar human-like CT and MR properties (i.e. Hounsfield units and relaxation times). Methods: Materials of interested such as common CT QA phantom materials, and other proprietary gels/silicones from Polytek, SmoothOn, and CompositeOne were first scanned on a GE 1.5T Signa HDxT MR. Materials that could be seen on both T1-weighted and T2-weighted images were then scanned on a GE Lightspeed RT16 CT simulator and a GE Discovery 750HD CT scanner and their HU values were then measured. The materials with matching HU values of lung (−500 to −700HU), muscle (+40HU) and soft tissue (+100 to +300HU) were further scanned on GE 1.5T Signa HDx to measure their T1 and T2 relaxation times from varying parameters of TI and TE. Results: Materials that could be visualized on T1-weighted and T2-weighted images from a 1.5T MR unit and had an appropriate average CT number, −650, −685, 46,169, and 168 HUs were: compressed cork saturated with water, Polytek Platsil™ Gel-00 combined with mini styrofoam balls, radiotherapy bolus material, SmoothOn Dragon-Skin™ and SmoothOn Ecoflex™, respectively. Conclusion: Post processing analysis is currently being performed to accurately map T1 and T2 values for each material tested. From previous MR visualization and CT examinations it is expected that Dragon-Skin™, Ecoflex™ and bolus will have values consistent with tissue and tumor substitutes. We also expect compressed cork statured with water, and Polytek™-styrofoam combination to have approximate T1 and T2 values suitable for lung-equivalent materials

  18. Tomographic anthropomorphic models. Pt. 1

    International Nuclear Information System (INIS)

    The first generation of heterogenoeous anthropomorphic mathematical models to be used in dose calculations was the MIRD-5 adult phantom, followed by the pediatric MIRD-type phantoms and by the GSF sex-specific phantoms ADAM and EVA. A new generation of realistic anthropomorphic models is now introduced. The organs and tissues of these models consist of a well defined number of volume elements (voxels), derived from computer tomographic (CT) data; consequently, these models were named voxel or tomographic models. So far two voxel models of real patients are available: one of an 8 week old baby and of a 7 year old child. For simplicity, the model of the baby will be referred to as BABY and that of the child as CHILD. In chapter 1 a brief literature review is given on the existing mathematical models and their applications. The reasons that lead to the construction of the new CT models is discussed. In chapter 2 the technique is described which allows to convert any physical object into computer files to be used for dose calculations. The technique which produces three dimensional reconstructions of high resolution is discussed. In chapter 3 the main characteristics of the models of the baby and child are given. Tables of organ masses and volumes are presented together with three dimensional images of some organs and tissues. A special mention is given to the assessment of bone marrow distribution. Chapter 4 gives a short description of the Monte Carlo code used in conjunction with the models to calculate organ and tissue doses resulting from photon exposures. Some technical details concerning the computer files which describe the models are also given. (orig./HP)

  19. Automatic Synthesis of Anthropomorphic Pulmonary CT Phantoms

    OpenAIRE

    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 sc...

  20. Adult phantoms as function of body mass, height and posture by using caucasian anthropomorphic statistics; Fantomas adultos em funcao da massa corporal, da altura e da postura usando estatisticas antropometricas caucasianas

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, Richard; Cassola, Vagner Ferreira; Lira, Carlos Alberto Brayner de Oliveira; Khoury, Helen Jamil, E-mail: rkramer@uol.com.b, E-mail: vagner.cassola@gmail.co [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear; Milian, Felix Mas, E-mail: felix_mas_milian@yahoo.co [Universidade Estadual de Santa Cruz (UESC), Ilheus, BA (Brazil). Dept. de Ciencias Exatas e Tecnologia

    2011-10-26

    The CALLDose{sub X} 4.0 computer program uses conversion coefficients for the MASH and FASH adult phantoms on the vertical and supine postures, representing the standard man and woman according to ICRP 90 and are called 'basic phantoms'. For improving the representation of real patients in the CALLDose{sub X}, this paper developed adults phantoms as function of mass and height by using anthropometric data from nine of them prevailing caucasian countries

  1. Radiation dose and cancer risk from pediatric CT examinations on 64-slice CT: A phantom study

    International Nuclear Information System (INIS)

    Objective: To measure the radiation dose from CT scans in an anthropomorphic phantom using a 64-slice MDCT, and to estimate the associated cancer risk. Materials and methods: Organ doses were measured with a 5-year-old phantom and thermoluminescent dosimeters. Four protocols; head CT, thorax CT, abdomen CT and pelvis CT were studied. Cancer risks, in the form of lifetime attributable risk (LAR) of cancer incidence, were estimated by linear extrapolation using the organ radiation doses and the LAR data. Results: The effective doses for head, thorax, abdomen and pelvis CT, were 0.7 mSv, 3.5 mSv, 3.0 mSv, 1.3 mSv respectively. The organs with the highest dose were; for head CT, salivary gland (22.33 mGy); for thorax CT, breast (7.89 mGy); for abdomen CT, colon (6.62 mGy); for pelvis CT, bladder (4.28 mGy). The corresponding LARs for boys and girls were 0.015-0.053% and 0.034-0.155% respectively. The organs with highest LARs were; for head CT, thyroid gland (0.003% for boys, 0.015% for girls); for thorax CT, lung for boys (0.014%) and breast for girls (0.069%); for abdomen CT, colon for boys (0.017%) and lung for girls (0.016%); for pelvis CT, bladder for both boys and girls (0.008%). Conclusion: The effective doses from these common pediatric CT examinations ranged from 0.7 mSv to 3.5 mSv and the associated lifetime cancer risks were found to be up to 0.16%, with some organs of higher radiosensitivity including breast, thyroid gland, colon and lungs.

  2. Dosimetry in thorax X-rays

    International Nuclear Information System (INIS)

    The dose to the entrance of thorax during a radiological study has been measured in a phantom of paraffin and with thermoluminescent dosemeters. This work was realized in the living room 1 of the X-rays service of the General Hospital No. 1 IMSS in Zacatecas. For the study thermoluminescent dosemeters of CaSO4:Dy were used. The irradiation of the thoracic region is the more studied through the conventional radiology, method that continues occupying the first place as diagnostic in diverse pathologies due to generates images of the heart, lungs, spine, etc. As well as can to observe the location of subclavian catheters, nasogastric sound, endotracheal tubes and umbilical catheters. The magnitude of the dose that is received during the realization of this study type is not usually measured, since the main concern is to have a good image to make a good diagnostic. The measurements were carried out using parameters of the equipment that were defined with base to the experience of the technical radiologist. It was found that the irradiation field is not uniform and that in any point where the dose was measured it is not exceeded the 7 mGy settled by the Mexican Official Standard-157-SSA-1996 for a thorax study. (author)

  3. The measurement of organic radiation dose of multi-slice CT scanning by using the Chinese anthropomorphic chest phantom%中国人仿真胸部体模检测多层螺旋CT扫描组织器官剂量的研究

    Institute of Scientific and Technical Information of China (English)

    彭刚; 曾勇明; 罗天友; 赵峰; 张志伟; 郁仁强; 彭盛坤

    2011-01-01

    目的 利用中国人仿真胸部模型来测量不同噪声指数下胸部各组织器官的吸收剂量,计算有效剂量(ED)并对MSCT胸部扫描进行剂量评估.方法 对CDP-1C型中国人仿真胸部体模在CT体层解剖和X线衰减两方面进行等效性论证;通过在体模内布放热释光剂量计(TLD)来测量不同噪声水平下各组织器官的吸收剂量,并记录相应的剂量长度乘积(DLP);将两者分别换算为ED后选择单因素t检验方法进行对比研究,分析自动管电流调制(ATCM)技术时不同噪声指数胸部CT扫描的剂量水平.结果 中国人仿真胸部体模与成人CT胸部图像的结构相似.体模主要器官平均CT值为肺-788.04 HU、心脏45.64 HU、肝脏65.84 HU、脊柱254.32 HU,与成人偏差程度分别为肺0.10%、心脏3.04%、肝脏4.49%、脊柱4.36%.肝脏的平均CT值差异有统计学意义(t=-8.705,P<0.05);肺、心脏和脊柱平均CT值与人体差异无统计学意义(t值分别为-0.752、-1.219、-1.138,P>0.05).当噪声指数从8.5逐渐增至22.5时,DLP从393.57 mGy·cm递减至78.75 mGy·cm,各器官吸收剂量呈下降趋势(以肺为例,平均吸收剂量从22.38 mGy递减至3.66 mGy).应用DLP所计算的ED较器官吸收剂量计算的ED偏低(以噪声指数为8.5为例,两种方法的ED分别为6.69和8.77 mSv).结论 应用中国人仿真体模来进行CT剂量评估更为准确;基于ATCM技术的胸部CT扫描噪声指数设定至少应大于8.5.%Objective Using the Chinese anthropomorphic chest phantom to measure the absorbed dose of various tissues and organs under different noise index, and to assess the radiation dose of MSCT chest scanning with the effective dose(ED). Methods The equivalence of the Chinese anthropomorphic chest phantom(CDP-1C) and the adult chest on CT sectional anatomy and X-ray attenuation was demonstrated. The absorbed doses of various tissues and organs under different noise index were measured by laying thermoluminescent

  4. Quality assurance in RapidArc with Alderson anthropomorphic phantom using radiochromic film in comparison to MATLAB; Controle de qualidade em RapidArc com simulador de corpo humano antropomorfico Alderson utilizando filme radiocromico em comparacao ao MATLAB

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Paulo L.; Silva, Leonardo P.; Santos, Maira R.; Trindade, Cassia; Martins, Lais P.; Batista, Delano V.S., E-mail: Paulo8_lgarcia@hotmail.com [Instituto Nacional de Cancer (INCA), Rio de Janeiro, RJ (Brazil); Alves, Victor G. [Instituto Nacional de Cancer (SQRIS/INCA), Rio de Janeiro, RJ (Brazil). Servico de Qualidade em Radiacoes Ionizantes

    2012-12-15

    This paper presented the quality control for RapidArc using an Alderson human body phantom and radiochromic film as an alternative system to approve the treatment plan for brain tumor. Thus, it was comprised the dose distributions provided by the treatment planning system with those measured by the film radiochromic. The gamma index (Γ) analysis, to verify the acceptability of the dose distribution, was 95% of approved points, with the mostly non-compliance points in regions near the PTV’s edges. These non-compliance points may be associated to transmission blades aspects, because the regions near the edges present significant losses compared to the central areas. Also, MATLAB has proved an effective tool for that measurements and it can be used in quality assurance programs. (author)

  5. Tomographic anthropomorphic models. Pt. 4. Organ doses for adults due to idealized external photon exposures

    International Nuclear Information System (INIS)

    The present report contains extensive tables and figures of conversion coefficients of organ and tissue equivalent dose, normalised to air kerma free in air for voxel anthropomorphic phantoms and for standard geometries of external photon radiation, estimated with Monte Carlo techniques. Four realistic adult voxel phantoms were used for the calculations, based on computed tomographic data of real people: three male phantoms, two of them being of average size, one representing a big man, and one female phantom of a tall and somewhat over weighted woman. (orig.)

  6. Tomographic anthropomorphic models. Pt. 4. Organ doses for adults due to idealized external photon exposures

    CERN Document Server

    Zankl, M; Petoussi-Henss, N; Regulla, D

    2002-01-01

    The present report contains extensive tables and figures of conversion coefficients of organ and tissue equivalent dose, normalised to air kerma free in air for voxel anthropomorphic phantoms and for standard geometries of external photon radiation, estimated with Monte Carlo techniques. Four realistic adult voxel phantoms were used for the calculations, based on computed tomographic data of real people: three male phantoms, two of them being of average size, one representing a big man, and one female phantom of a tall and somewhat over weighted woman.

  7. Dual wavelength optical CT scanning of anthropomorphic shaped 3D dosimeters

    International Nuclear Information System (INIS)

    To create an optical density map of 3D dosimeter phantoms, the ratio of the transmission profile (either a line or planar) acquired after irradiation of the dosimeter and a pre-irradiation reference scan of the same dosimeter phantom is taken. Any uncertainty in repositioning of the phantom may result in an uncertainty in the optical density map and finally also in the derived dose maps. Correct repositioning is paramount when scanning noncylindrical dosimeter phantoms as any repositioning error will give rise to severe imaging artifacts. We hereby propose a different scanning technique that does not require any repositioning of the dosimeter phantom. In this method, no pre-irradiation san is recorded but the dosimeter phantom is scanned twice with light at two different wavelengths. It is demonstrated that this method is accurate in scanning non-cylindrical anthropomorphic shaped phantoms

  8. IGRT/ART phantom with programmable independent rib cage and tumor motion

    Energy Technology Data Exchange (ETDEWEB)

    Haas, Olivier C. L., E-mail: o.haas@coventry.ac.uk [Control Theory and Applications Centre, Coventry University, Coventry CV1 2TL (United Kingdom); Mills, John A.; Land, Imke; Mulholl, Pete; Menary, Paul; Crichton, Robert; Wilson, Adrian; Sage, John [Department of Clinical Physics and Bioengineering, University Hospital, Coventry CV2 2DX (United Kingdom); Anna, Morenc [University Hospitals of Leicester NHS Trust, Leicester Royal Infirmary, Leicester, LE1 5WW (United Kingdom); Depuydt, Tom [Radiotherapy, Medical Physics Group, University Hospital UZ Brussel, Laarbeeklaan 101 - 1090 Brussels (Belgium)

    2014-02-15

    Purpose: This paper describes the design and experimental evaluation of the Methods and Advanced Equipment for Simulation and Treatment in Radiation Oncology (MAESTRO) thorax phantom, a new anthropomorphic moving ribcage combined with a 3D tumor positioning system to move target inserts within static lungs. Methods: The new rib cage design is described and its motion is evaluated using Vicon Nexus, a commercial 3D motion tracking system. CT studies at inhale and exhale position are used to study the effect of rib motion and tissue equivalence. Results: The 3D target positioning system and the rib cage have millimetre accuracy. Each axis of motion can reproduce given trajectories from files or individually programmed sinusoidal motion in terms of amplitude, period, and phase shift. The maximum rib motion ranges from 7 to 20 mm SI and from 0.3 to 3.7 mm AP with LR motion less than 1 mm. The repeatability between cycles is within 0.16 mm root mean square error. The agreement between CT electron and mass density for skin, ribcage, spine hard and inner bone as well as cartilage is within 3%. Conclusions: The MAESTRO phantom is a useful research tool that produces programmable 3D rib motions which can be synchronized with 3D internal target motion. The easily accessible static lungs enable the use of a wide range of inserts or can be filled with lung tissue equivalent and deformed using the target motion system.

  9. SU-E-I-80: Quantification of Respiratory and Cardiac Motion Effect in SPECT Acquisitions Using Anthropomorphic Models: A Monte Carlo Simulation Study

    Energy Technology Data Exchange (ETDEWEB)

    Papadimitroulas, P; Kostou, T; Kagadis, G [University of Patras, Rion, Ahaia (Greece); Loudos, G [Technological Educational Institute of Athens, Egaleo, Attika (Greece)

    2015-06-15

    Purpose: The purpose of the present study was to quantify, evaluate the impact of cardiac and respiratory motion on clinical nuclear imaging protocols. Common SPECT and scintigraphic scans are studied using Monte Carlo (MC) simulations, comparing the resulted images with and without motion. Methods: Realistic simulations were executed using the GATE toolkit and the XCAT anthropomorphic phantom as a reference model for human anatomy. Three different radiopharmaceuticals based on 99mTc were studied, namely 99mTc-MDP, 99mTc—N—DBODC and 99mTc—DTPA-aerosol for bone, myocardium and lung scanning respectively. The resolution of the phantom was set to 3.5 mm{sup 3}. The impact of the motion on spatial resolution was quantified using a sphere with 3.5 mm diameter and 10 separate time frames, in the ECAM modeled SPECT scanner. Finally, respiratory motion impact on resolution and imaging of lung lesions was investigated. The MLEM algorithm was used for data reconstruction, while the literature derived biodistributions of the pharmaceuticals were used as activity maps in the simulations. Results: FWHM was extracted for a static and a moving sphere which was ∼23 cm away from the entrance of the SPECT head. The difference in the FWHM was 20% between the two simulations. Profiles in thorax were compared in the case of bone scintigraphy, showing displacement and blurring of the bones when respiratory motion was inserted in the simulation. Large discrepancies were noticed in the case of myocardium imaging when cardiac motion was incorporated during the SPECT acquisition. Finally the borders of the lungs are blurred when respiratory motion is included resulting to a dislocation of ∼2.5 cm. Conclusion: As we move to individualized imaging and therapy procedures, quantitative and qualitative imaging is of high importance in nuclear diagnosis. MC simulations combined with anthropomorphic digital phantoms can provide an accurate tool for applications like motion correction

  10. SU-E-I-80: Quantification of Respiratory and Cardiac Motion Effect in SPECT Acquisitions Using Anthropomorphic Models: A Monte Carlo Simulation Study

    International Nuclear Information System (INIS)

    Purpose: The purpose of the present study was to quantify, evaluate the impact of cardiac and respiratory motion on clinical nuclear imaging protocols. Common SPECT and scintigraphic scans are studied using Monte Carlo (MC) simulations, comparing the resulted images with and without motion. Methods: Realistic simulations were executed using the GATE toolkit and the XCAT anthropomorphic phantom as a reference model for human anatomy. Three different radiopharmaceuticals based on 99mTc were studied, namely 99mTc-MDP, 99mTc—N—DBODC and 99mTc—DTPA-aerosol for bone, myocardium and lung scanning respectively. The resolution of the phantom was set to 3.5 mm3. The impact of the motion on spatial resolution was quantified using a sphere with 3.5 mm diameter and 10 separate time frames, in the ECAM modeled SPECT scanner. Finally, respiratory motion impact on resolution and imaging of lung lesions was investigated. The MLEM algorithm was used for data reconstruction, while the literature derived biodistributions of the pharmaceuticals were used as activity maps in the simulations. Results: FWHM was extracted for a static and a moving sphere which was ∼23 cm away from the entrance of the SPECT head. The difference in the FWHM was 20% between the two simulations. Profiles in thorax were compared in the case of bone scintigraphy, showing displacement and blurring of the bones when respiratory motion was inserted in the simulation. Large discrepancies were noticed in the case of myocardium imaging when cardiac motion was incorporated during the SPECT acquisition. Finally the borders of the lungs are blurred when respiratory motion is included resulting to a dislocation of ∼2.5 cm. Conclusion: As we move to individualized imaging and therapy procedures, quantitative and qualitative imaging is of high importance in nuclear diagnosis. MC simulations combined with anthropomorphic digital phantoms can provide an accurate tool for applications like motion correction

  11. Development of pathological anthropomorphic models using 3D modelling techniques for numerical dosimetry

    International Nuclear Information System (INIS)

    Computational exposure models can be used to estimate human body absorbed dose in a series of situations such as X-Ray exams for diagnosis, accidents and medical treatments. These models are fundamentally composed of an anthropomorphic simulator (phantom), an algorithm that simulates a radioactive source and a Monte Carlo Code. The accuracy of data obtained in the simulation is strongly connected to the adequacy of such simulation to the real situation. The phantoms are one of the key factors for the researcher manipulation. They are generally developed in supine position and its anatomy is patronized by compiled data from international institutions such as ICRP or ICRU. Several pathologies modify the structure of organs and body tissues. In order to measure how significant these alterations are, an anthropomorphic model was developed for this study: patient mastectomies. This model was developed using voxel phantom FASH and then coupled with EGSnrc Monte Carlo code

  12. Monte Carlo Simulations for Homeland Security Using Anthropomorphic Phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Burns, Kimberly A. [Georgia Inst. of Technology, Atlanta, GA (United States)

    2008-01-01

    A radiological dispersion device (RDD) is a device which deliberately releases radioactive material for the purpose of causing terror or harm. In the event that a dirty bomb is detonated, there may be airborne radioactive material that can be inhaled as well as settle on an individuals leading to external contamination.

  13. An experimental study of comparing digital tomosynthesis and multi-slice CT scanning for the detection of pulmonary nodules using the anthropomorphic chest phantom%数字断层融合技术与多层CT胸部扫描病变检出及辐射剂量的体模研究

    Institute of Scientific and Technical Information of China (English)

    赵峰; 曾勇明; 彭盛坤; 彭刚; 郁仁强; 谭欢; 蔡文晶

    2012-01-01

    目的 评价数字断层融合(DTS)技术及MSCT胸部扫描对肺结节的检出率及辐射剂量水平.方法 采用DTS及MSCT分别扫描共置入45个肺模拟结节及热释光剂量计(TLD)的胸部体模,记录并储存图像,测量胸部主要组织器官的吸收剂量并计算有效剂量.采用Fisher确切概率法(样本数小于30)和x2检验,比较DTS与MSCT扫描对模拟结节检出率的差别;两种检查方法器官吸收剂量的比较采用配对t检验.结果 DTS与MSCT对肺结节的检出率分别为66.7%( 30/45)和91.1% (41/45),差异有统计学意义(x2=8.073,P<0.05);对CT值为- 650 HU的磨玻璃结节检出率分别为73.3% (11/15)和93.3%( 14/15),差异无统计学意义(P>0.05).DTS对CT值为- 800 HU及直径<8 mm的磨玻璃结节检出率分别为33.3% (5/15)和16.7% (2/12),MSCT的检出率分别为80.0% (12/15)和66.7% (8/12),两者差异均有统计学意义(P<0.05).胸部DTS检查各主要组织器官(肺、胸椎、心脏、肝脏、乳腺和甲状腺)的吸收剂量明显低于MSCT,两者差异有统计学意义(上述部位的t值分别为19.69、30.01、16.33、5.06、9.43和8.05,P值均<0.05).DTS与MSCT胸部扫描的有效剂量分别为0.65和7.71 mSv.结论 DTS对于CT值为- 650 HU的磨玻璃结节检出率与MSCT相近,对极低密度(- 800 HU)磨玻璃结节及直径<8 mm的磨玻璃结节检出率低.肺部结节检查时,DTS有效剂量低于MSCT,约为MSCT辐射剂量的8.41%.%Objective To compare detection rate of pulmonary nodules and the radiation doses of digital tomosynthesis (DTS) and MSCT chest scanning by using the anthropomorphic chest phantom which contains thermoluminescent dosimeters ( TLD ) and simulated pulmonary nodules. Methods The radiation doses of DTS and MSCT scanning were measured by using the anthropomorphic chest phantom which contains 45 TLD and simulated pulmonary nodules.The radiation doses of najor organs were converted into effective dose ( ED

  14. ICRU activity in the field of phantoms in diagnostic radiology

    International Nuclear Information System (INIS)

    The ICRU Report on 'Phantoms and Computational Models in Radiation Therapy, Diagnosis and Protection' is presented. Different types of phantoms may be defined. They may be broadly categorized according to their primary function: dosimetry, calibration and imaging. Within each functional category, there are 3 types or designs of phantoms: body phantoms (anthropomorphic), standard phantoms and reference phantoms (used in the definition and specification of certain radiation quantities). In radiological imaging, anthropomorphic body phantoms are used for measuring the absorbed dose distribution resulting from imaging procedures. Standard phantoms have simple reproducible geometry and are used for comparing measurements under standard conditions of exposure. Imaging phantoms are useful for evaluating a given imaging system; they contain different types of test pieces. The report contains a major section on human anatomy, from fetus to adult with the variations due to ethnic origin. Tolerance levels for the phantoms (composition, dimensions) are proposed and quality assurance programs are outlined. The report contains extensive appendices; human anatomical data and full specification of over 80 phantoms and computational models. ICRU Report 46 on 'Photon, electron, proton and neutron interaction data for body tissues' is closely related to the field of phantoms. It is a logical continuation on ICRU Report 44 (1989) on 'Tissue substitutes in radiation dosimetry and measurements' and contains the interaction data for more than 100 tissues, from fetal to adult, including some diseased tissues

  15. Investigating human infant anthropomorphism in products

    NARCIS (Netherlands)

    Hellen, K.; Saaksjarvi, M.C.

    2012-01-01

    In this paper we set out to investigate the nature and effects of infant anthropomorphism in products, i.e. products that share features of human infants. Across four studies, evidence suggests that infant anthropomorphism comprise four dimensions: sweetness, simplicity, sympathy, and smallness. We

  16. Experimental Injury Biomechanics of the Pediatric Thorax and Abdomen

    Science.gov (United States)

    Kent, Richard; Ivarsson, Johan; Maltese, Matthew R.

    Motor vehicle crashes are the leading cause of death and injury for children in the United States. Pediatric anthropomorphic test devices (ATD) and computational models are important tools for the evaluation and optimization of automotive restraint systems for child occupants. The thorax interacts with the restraints within the vehicle, and any thoracic model must mimic this interaction in a biofidelic manner to ensure that restraint designs protect humans as intended. To define thoracic biofidelity for adults, Kroell et al. (1974) conducted blunt impacts to the thoraces of adult postmortem human subjects (PMHS), which have formed the basis for biofidelity standards for modern adult ATD thoraces (Mertz et al. 1989). The paucity of pediatric PMHS for impact research led to the development of pediatric model biofidelity requirements through scaling. Geometric scale factors and elastic moduli of skull and long bone have been used to scale the adult thoracic biofidelity responses to the 3-, 6-, and 10-year-old child (Irwin and Mertz 1997; Mertz et al. 2001; van Ratingen et al. 1997). There is currently a need for data that apply to the child without scaling, both for validation of scaling methods used in the past and to confirm the validity of the specifications currently used to develop models of the child.

  17. Comparison of different phantoms used in digital diagnostic imaging

    Energy Technology Data Exchange (ETDEWEB)

    Bor, Dogan, E-mail: bor@eng.ankara.edu.tr [Ankara University, Faculty of Engineering, Department of Engineering Physics. Tandogan, 06100 Ankara (Turkey); Unal, Elif, E-mail: elf.unall@gmail.com [Radat Dosimetry Laboratory Services, 06830, Golbasi, Ankara (Turkey); Uslu, Anil, E-mail: m.aniluslu@gmail.com [Radat Dosimetry Laboratory Services, 06830, Golbasi, Ankara (Turkey)

    2015-09-21

    The organs of extremity, chest, skull and lumbar were physically simulated using uniform PMMA slabs with different thicknesses alone and using these slabs together with aluminum plates and air gaps (ANSI Phantoms). The variation of entrance surface air kerma and scatter fraction with X-ray beam qualities was investigated for these phantoms and the results were compared with those measured from anthropomorphic phantoms. A flat panel digital radiographic system was used for all the experiments. Considerable variations of entrance surface air kermas were found for the same organs of different designs, and highest doses were measured for the PMMA slabs. A low contrast test tool and a contrast detail test object (CDRAD) were used together with each organ simulation of PMMA slabs and ANSI phantoms in order to test the clinical image qualities. Digital images of these phantom combinations and anthropomorphic phantoms were acquired in raw and clinically processed formats. Variation of image quality with kVp and post processing was evaluated using the numerical metrics of these test tools and measured contrast values from the anthropomorphic phantoms. Our results indicated that design of some phantoms may not be efficient enough to reveal the expected performance of the post processing algorithms.

  18. Comparison of different phantoms used in digital diagnostic imaging

    International Nuclear Information System (INIS)

    The organs of extremity, chest, skull and lumbar were physically simulated using uniform PMMA slabs with different thicknesses alone and using these slabs together with aluminum plates and air gaps (ANSI Phantoms). The variation of entrance surface air kerma and scatter fraction with X-ray beam qualities was investigated for these phantoms and the results were compared with those measured from anthropomorphic phantoms. A flat panel digital radiographic system was used for all the experiments. Considerable variations of entrance surface air kermas were found for the same organs of different designs, and highest doses were measured for the PMMA slabs. A low contrast test tool and a contrast detail test object (CDRAD) were used together with each organ simulation of PMMA slabs and ANSI phantoms in order to test the clinical image qualities. Digital images of these phantom combinations and anthropomorphic phantoms were acquired in raw and clinically processed formats. Variation of image quality with kVp and post processing was evaluated using the numerical metrics of these test tools and measured contrast values from the anthropomorphic phantoms. Our results indicated that design of some phantoms may not be efficient enough to reveal the expected performance of the post processing algorithms

  19. Patient specific 3D printed phantom for IMRT quality assurance

    International Nuclear Information System (INIS)

    The purpose of this study was to test the feasibility of a patient specific phantom for patient specific dosimetric verification. Using the head and neck region of an anthropomorphic phantom as a substitute for an actual patient, a soft-tissue equivalent model was constructed with the use of a 3D printer. Calculated and measured dose in the anthropomorphic phantom and the 3D printed phantom was compared for a parallel-opposed head and neck field geometry to establish tissue equivalence. A nine-field IMRT plan was constructed and dose verification measurements were performed for the 3D printed phantom as well as traditional standard phantoms. The maximum difference in calculated dose was 1.8% for the parallel-opposed configuration. Passing rates of various dosimetric parameters were compared for the IMRT plan measurements; the 3D printed phantom results showed greater disagreement at superficial depths than other methods. A custom phantom was created using a 3D printer. It was determined that the use of patient specific phantoms to perform dosimetric verification and estimate the dose in the patient is feasible. In addition, end-to-end testing on a per-patient basis was possible with the 3D printed phantom. Further refinement of the phantom construction process is needed for routine use. (paper)

  20. Anthropomorphism and Teleology in Reasoning about Biological Phenomena.

    Science.gov (United States)

    Tamir, Pinchas; Zohar, Anat

    1991-01-01

    Reports on interviews with 28 high school biology students in Jerusalem concerning teleological and anthropomorphic formulations and reasoning. Results indicate acceptance of anthropomorphic formulations does not imply a prevalence of anthropomorphic reasoning. Most high school students can distinguish between anthropomorphic formulations and…

  1. Balancing of the anthropomorphous robot walking

    Science.gov (United States)

    Devaev, V. M.; Nikitina, D. V.; Fadeev, A. Y.

    2016-06-01

    Anthropomorphic robots are designed a human environment operates: buildings and structures, cabs and etc. The movement of these robots is carried out by walking which provides high throughput to overcome natural and manmade obstacles. The article presents some algorithm results for dynamic walking on the anthropomorphic robot AR601 example. The work is performed according to the Russian Government Program of Competitive Growth of Kazan Federal University.

  2. Creating an anthropomorphic digital MR phantom—an extensible tool for comparing and evaluating quantitative imaging algorithms

    Science.gov (United States)

    Bosca, Ryan J.; Jackson, Edward F.

    2016-01-01

    Assessing and mitigating the various sources of bias and variance associated with image quantification algorithms is essential to the use of such algorithms in clinical research and practice. Assessment is usually accomplished with grid-based digital reference objects (DRO) or, more recently, digital anthropomorphic phantoms based on normal human anatomy. Publicly available digital anthropomorphic phantoms can provide a basis for generating realistic model-based DROs that incorporate the heterogeneity commonly found in pathology. Using a publicly available vascular input function (VIF) and digital anthropomorphic phantom of a normal human brain, a methodology was developed to generate a DRO based on the general kinetic model (GKM) that represented realistic and heterogeneously enhancing pathology. GKM parameters were estimated from a deidentified clinical dynamic contrast-enhanced (DCE) MRI exam. This clinical imaging volume was co-registered with a discrete tissue model, and model parameters estimated from clinical images were used to synthesize a DCE-MRI exam that consisted of normal brain tissues and a heterogeneously enhancing brain tumor. An example application of spatial smoothing was used to illustrate potential applications in assessing quantitative imaging algorithms. A voxel-wise Bland-Altman analysis demonstrated negligible differences between the parameters estimated with and without spatial smoothing (using a small radius Gaussian kernel). In this work, we reported an extensible methodology for generating model-based anthropomorphic DROs containing normal and pathological tissue that can be used to assess quantitative imaging algorithms.

  3. Phantom pain

    OpenAIRE

    Duca, Kristina; Muscat, Richard

    2016-01-01

    Almost anyone with a limb amputation experiences phantom sensations. Moreover, the majority of amputees experience pain. This phenomenon is known as ‘Phantom pain’ and is described as the pain felt from a body part, usually a limb, which is no longer present. Several mechanisms have been proposed in attempt to explain this phenomenon with some being more prevalent than others. Cortical remapping seems to explain a substantial part of the occurrence of phantom pain and will be focu...

  4. A human head phantom for experimental dosimetry

    International Nuclear Information System (INIS)

    In order to achieve a better understanding of the behavior of nuclear particles in a human head experiment a phantom preserving similar tissues as well as similar anthropomorphic characteristics was used. In this work a biologic equivalent tissue material was developed, maintaining the chemical composition and tissue density, based on enriched PMMA. A humanoid head phantom was built using a human skull as a base, donated by the Morphology Department of the Institute for Biologic Sciences-ICB/UFMG. Muscles were replaced with biologic equivalent tissue material following anatomic precepts. The phantom presents: formalized animal salivary glands, brain and submandibular lymph nodes; human teeth; hair; prosthetic eyes and nose as well as human equivalent skin containing silicone and animal collagen. This phantom present several important conditions as human morphological characteristics, equivalent biological tissue and the head bone structure. It will be used in radiotherapy and brachytherapy studies, dosimetry and quality control of medical diagnostic image. (author)

  5. Anthropomorphic Telemanipulation System in Terminus Control Mode

    Science.gov (United States)

    Jau, Bruno M.; Lewis, M. Anthony; Bejczy, Antal K.

    1994-01-01

    This paper describes a prototype anthropomorphic kinesthetic telepresence system that is being developed at JPL. It utilizes dexterous terminus devices in the form of an exoskeleton force-sensing master glove worn by the operator and a replica four finger anthropomorphic slave hand. The newly developed master glove is integrated with our previously developed non-anthropomorphic six degree of freedom (DOF) universal force-reflecting hand controller (FRHC). The mechanical hand and forearm are mounted to an industrial robot (PUMA 560), replacing its standard forearm. The notion of 'terminus control mode' refers to the fact that only the terminus devices (glove and robot hand) are of anthropomorphic nature, and the master and slave arms are non-anthropomorphic. The system is currently being evaluated, focusing on tool handling and astronaut equivalent task executions. The evaluation revealed the system's potential for tool handling but it also became evident that hand tool manipulations and space operations require a dual arm robot. This paper describes the system's principal components, its control and computing architecture, discusses findings of the tool handling evaluation, and explains why common tool handling and EVA space tasks require dual arm robots.

  6. Dose verification of radiotherapy for lung cancer by using plastic scintillator dosimetry and a heterogeneous phantom

    DEFF Research Database (Denmark)

    Ottosson, Wiviann; Behrens, C. F.; Andersen, Claus E.

    2015-01-01

    of this study was to investigate the performance of a commercial treatment planning system (TPS) using a PSD and a specially designed thorax phantom with lung tumor inserts. 10 treatment plans of different complexity and phantom configurations were evaluated. Although the TPS agreed well with the...

  7. 49 CFR 572.185 - Thorax (upper torso) assembly.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Thorax (upper torso) assembly. 572.185 Section 572... Impact Crash Test Dummy, 50th Percentile Adult Male § 572.185 Thorax (upper torso) assembly. (a) The thorax assembly of the dummy must meet the requirements of both (b) and (c) of this section. Section...

  8. Bases for calibration of whole body counters using anthropomorphic physical simulators

    International Nuclear Information System (INIS)

    The quantification of radionuclides in the human body can be carried out through in vivo measurements performed in facilities generically called whole body counters. The calibration of such units is usually done by using physical anthropomorphic phantoms, which can be defined as artificial structures with geometrical characteristics and attenuation properties similar to the living tissues. This work presents the development of the phantoms necessary to the monitoring of the internal contamination by the radionuclides manipulated in Brazil. It also presents the procedures for the calibration of the detectors used for the in vivo measurements. The developed phantoms are applied in the determination of radionuclides deposited in specific organs, such as Th-232 and Am-241 in the lungs and skull, isotopes of iodine in the thyroid and photon emitters in the energy range from 100 to 3000 keV in the whole body. (author)

  9. Diaphragmatic Hernia Presenting as Empyema Thorax

    Directory of Open Access Journals (Sweden)

    Satyendra Dhar, Sanjay K. Bhasin, J.G. Langer

    2005-01-01

    Full Text Available Diaphragmatic injuries are relatively rare and result from either blunt or penetrating trauma. Regardlessof mechanism, seemingly innocent penetrating injuries may be long forgotten by the patient and arethe most commonly missed diaphragmatic injury. Diagnosis is often missed and high index of suspicionis vital. The clinical signs associated with a diaphragmatic hernia can range from no outward signs toimmediately life-threatening respiratory compromise. We report an unusual case of diaphragmatichernia presenting as empyema thorax after suffering from penetrating injury.

  10. Trauma imaging in the thorax and abdomen

    International Nuclear Information System (INIS)

    This book thoroughly covers the radiologic diagnosis of traumatic injuries of the thorax and abdomen with special consideration given to the physical principles governing blunt, blast, and penetrating trauma and to the pathophysiology which they cause. The clinical experience forming the major data base for this book is drawn from the Ramban Medical Center in Haifa, Israel, the major trauma center for the Middle East wars

  11. Human phantom

    CERN Multimedia

    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.

  12. Coronary calcium mass scores measured by identical 64-slice MDCT scanners are comparable : a cardiac phantom study

    NARCIS (Netherlands)

    Dijkstra, Hildebrand; Greuter, Marcel J. W.; Groen, Jaap M.; Vliegenthart-Proenca, Rozemarijn; Renema, KlaasJan W. K.; de Lange, Frank; Oudkerk, Matthijs

    2010-01-01

    To assess whether absolute mass scores are comparable or differ between identical 64-slice MDCT scanners of the same manufacturer and to compare absolute mass scores to the physical mass and between scan modes using a calcified phantom. A non-moving anthropomorphic phantom with nine calcifications o

  13. Dose reduction in thorax radiography in simulated neonates with additional filtration and digital luminescence radiography

    International Nuclear Information System (INIS)

    Purpose: To determine the minimum acceptable radiation dose for an adequate image quality in thorax a.p. radiographs of neonates using mobile X-ray equipment. Material and Methods: The influence of additional filtration (1.0 mm Al+0.1 mm Cu) on image quality and radiation dose was determined for the speed class 400 screen-film system (SFS) and digital luminescence radiography (DLR) by making radiographs of a test phantom. Conventional and digital thorax a.p. radiographs of a rabbit were produced using various tube current-time products. The quality of the rabbit radiographs was judged by eight radiologists applying image quality criteria according to the German guidelines and the recommendations of the European Community. Results: The added filter resulted in a dose reduction of 39% at 66 kV. DLR gave a further dose reduction of 25% in comparison to the speed class 400 SFS while maintaining adequate image quality, i.e. the radiographs were clinically acceptable with regard to quality criteria. Conclusion: The radiation dose resulting from thorax a.p. radiographs of neonates can be reduced by approximately 50% with the use of additional filtration and DLR. (orig.)

  14. Optimum location of external markers using feature selection algorithms for real-time tumor tracking in external-beam radiotherapy: a virtual phantom study.

    Science.gov (United States)

    Nankali, Saber; Esmaili Torshabi, Ahmad; Samadi Miandoab, Payam; Baghizadeh, Amin

    2016-01-01

    In external-beam radiotherapy, using external markers is one of the most reliable tools to predict tumor position, in clinical applications. The main challenge in this approach is tumor motion tracking with highest accuracy that depends heavily on external markers location, and this issue is the objective of this study. Four commercially available feature selection algorithms entitled 1) Correlation-based Feature Selection, 2) Classifier, 3) Principal Components, and 4) Relief were proposed to find optimum location of external markers in combination with two "Genetic" and "Ranker" searching procedures. The performance of these algorithms has been evaluated using four-dimensional extended cardiac-torso anthropomorphic phantom. Six tumors in lung, three tumors in liver, and 49 points on the thorax surface were taken into account to simulate internal and external motions, respectively. The root mean square error of an adaptive neuro-fuzzy inference system (ANFIS) as prediction model was considered as metric for quantitatively evaluating the performance of proposed feature selection algorithms. To do this, the thorax surface region was divided into nine smaller segments and predefined tumors motion was predicted by ANFIS using external motion data of given markers at each small segment, separately. Our comparative results showed that all feature selection algorithms can reasonably select specific external markers from those segments where the root mean square error of the ANFIS model is minimum. Moreover, the performance accuracy of proposed feature selection algorithms was compared, separately. For this, each tumor motion was predicted using motion data of those external markers selected by each feature selection algorithm. Duncan statistical test, followed by F-test, on final results reflected that all proposed feature selection algorithms have the same performance accuracy for lung tumors. But for liver tumors, a correlation-based feature selection algorithm, in

  15. Heart dosimetry in radiotherapy with hybrid computational phantoms

    International Nuclear Information System (INIS)

    segmentation were estimated for a left side breast radiotherapy by simulating different realistic coronary artery topologies in a single representative thorax anatomy and calculating doses due to beam sets, with and without irradiation of the internal mammary chain. The inter-topology variability of the mean dose to the most irradiated coronary artery, the left descending coronary artery, was assessed to 35% and 19% with and without the internal mammary chain irradiation, respectively; and it was of 76% and 49%, respectively, considering the dose to the most irradiated 2% of this coronary artery volume. Finally, an order of magnitude of the differences between measurements by radiochromic films and dose calculations by the ISOgray treatment planning system in the peripheral field area, has been estimated by for both a simple configuration (parallelepiped physical phantom, homogeneous media, open square field) and a complex configuration (anthropomorphic physical phantom, heterogeneous media, rectangular tangential beams with wedge filter). These differences were judged significant essentially around the geometrical border of the irradiation field for both configuration. (author)

  16. Cardiovascular dosimetry using hybrid computational phantoms after external radiotherapy

    International Nuclear Information System (INIS)

    segmentation were estimated for a left side breast radiotherapy by simulating different realistic coronary artery topologies in a single representative thorax anatomy and calculating doses due to beam sets, with and without irradiation of the internal mammary chain. The inter-topology variability of the mean dose to the most irradiated coronary artery, the left descending coronary artery, was assessed to 35% and 19% with and without the internal mammary chain irradiation, respectively; and it was of 76% and 49%, respectively, considering the dose to the most irradiated 2% of this coronary artery volume. Finally, an order of magnitude of the differences between measurements by radiochromic films and dose calculations by the ISOgray treatment planning system in the peripheral field area, has been estimated by for both a simple configuration (parallelepiped physical phantom, homogeneous media, open square field) and a complex configuration (anthropomorphic physical phantom, heterogeneous media, rectangular tangential beams with wedge filter). These differences were judged significant essentially around the geometrical border of the irradiation field for both configuration. (author)

  17. Use of realistic anthropomorphic models for calculation of radiation dose in nuclear medicine

    International Nuclear Information System (INIS)

    Anthropomorphic phantoms based on simple geometric structures have been used in radiation dose calculations for many years. We have now developed a series of anatomically realistic phantoms representing adults and children using body models based on non-uniform rational B-spline (NURBS), with organ and body masses based on the reference values given in ICRP Publication 89. Age-dependent models were scaled and shaped to represent the reference individuals described in ICRP 89 (male and female adults, newborns, 1-, 5-, 10- and 15-year-olds), using a software tool developed in Visual C++. Voxel-based versions of these models were used with GEANT4 radiation transport codes for calculation of specific absorbed fractions (SAFs) for internal sources of photons and electrons, using standard starting energy values. Organ masses in the models were within a few % of ICRP reference masses, and physicians reviewed the models for anatomical realism. Development of individual phantoms was much faster than manual segmentation of medical images, and resulted in a very uniform standardized phantom series. SAFs were calculated on the Vanderbilt multi node computing network (ACCRE). Photon and electron SAFs were calculated for all organs in all models, and were compared to values from similar phantoms developed by others. Agreement was very good in most cases; some differences were seen, due to differences in organ mass and geometry. This realistic phantom series represents a possible replacement for the Cristy/Eckerman series of the 1980's. Both phantom sets will be included in the next release of the OLINDA/EXM personal computer code, and the new phantoms will be made generally available to the research community for other uses. Calculated radiation doses for diagnostic and therapeutic radiopharmaceuticals will be compared with previous values. (author)

  18. Use of realistic anthropomorphic models for calculation of radiation dose in nuclear medicine

    International Nuclear Information System (INIS)

    Anthropomorphic phantoms based on simple geometric structures have been used in radiation dose calculations for many years. We have now developed a series of anatomically realistic phantoms representing adults and children using body models based on non-uniform rational B-spline (NURBS), with organ and body masses based on the reference values given in ICRP Publication 89. Age-dependent models were scaled and shaped to represent the reference individuals described in ICRP 89 (male and female adults, newborns, 1-, 5-, 10- and 15-year-olds), using a software tool developed in Visual C++. Voxel-based versions of these models were used with GEANT4 radiation transport codes for calculation of specific absorbed fractions (SAFs) for internal sources of photons and electrons, using standard starting energy values. Organ masses in the models were within a few % of ICRP reference masses, and physicians reviewed the models for anatomical realism. Development of individual phantoms was much faster than manual segmentation of medical images, and resulted in a very uniform standardized phantom series. SAFs were calculated on the Vanderbilt multinode computing network (ACCRE). Photon and electron SAFs were calculated for all organs in all models, and were compared to values from similar phantoms developed by others. Agreement was very good in most cases; some differences were seen, due to differences in organ mass and geometry. This realistic phantom series represents a possible replacement for the Cristy/Eckerman series of the 1980's. Both phantom sets will be included in the next release of the OLINDA/EXM personal computer code, and the new phantoms will be made generally available to the research community for other uses. Calculated radiation doses for diagnostic and therapeutic radiopharmaceuticals will be compared with previous values. (author)

  19. Biomechanical simulation of thorax deformation using finite element approach

    OpenAIRE

    Zhang, Guangzhi; Chen, Xian; Ohgi, Junji; Miura, Toshiro; Nakamoto, Akira; Matsumura, Chikanori; Sugiura, Seiryo; Hisada, Toshiaki

    2016-01-01

    Background The biomechanical simulation of the human respiratory system is expected to be a useful tool for the diagnosis and treatment of respiratory diseases. Because the deformation of the thorax significantly influences airflow in the lungs, we focused on simulating the thorax deformation by introducing contraction of the intercostal muscles and diaphragm, which are the main muscles responsible for the thorax deformation during breathing. Methods We constructed a finite element model of t...

  20. Thorax Injury Lowers Resistance to Infection in Drosophila melanogaster

    OpenAIRE

    Chambers, Moria C.; Jacobson, Eliana; Khalil, Sarah; Lazzaro, Brian P.

    2014-01-01

    The route of infection can profoundly affect both the progression and outcome of disease. We investigated differences in Drosophila melanogaster defense against infection after bacterial inoculation into two sites—the abdomen and the thorax. Thorax inoculation results in increased bacterial proliferation and causes high mortality within the first few days of infection. In contrast, abdomen inoculation results in minimal mortality and lower bacterial loads than thorax inoculation. Inoculation ...

  1. Development of pathological anthropomorphic models using 3D modelling techniques for numerical dosimetry; Desenvolvimento de modelos antropomorficos patologicos usando tecnicas de modelagem 3D para dosimetria numerica

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Kleber Souza Silva [Faculdade Integrada de Pernambuco (FACIPE), Recife, PE (Brazil); Barbosa, Antonio Konrado de Santana; Vieira, Jose Wilson [Instituto Federal de Educacao, Ciencia e Tecnologia de Pernambuco, Recife, PE (Brazil); Lima, Fernando Roberto de Andrade, E-mail: falima@cnen.gov.b [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2011-10-26

    Computational exposure models can be used to estimate human body absorbed dose in a series of situations such as X-Ray exams for diagnosis, accidents and medical treatments. These models are fundamentally composed of an anthropomorphic simulator (phantom), an algorithm that simulates a radioactive source and a Monte Carlo Code. The accuracy of data obtained in the simulation is strongly connected to the adequacy of such simulation to the real situation. The phantoms are one of the key factors for the researcher manipulation. They are generally developed in supine position and its anatomy is patronized by compiled data from international institutions such as ICRP or ICRU. Several pathologies modify the structure of organs and body tissues. In order to measure how significant these alterations are, an anthropomorphic model was developed for this study: patient mastectomies. This model was developed using voxel phantom FASH and then coupled with EGSnrc Monte Carlo code

  2. Using NURBS type phantoms for the investigation of morphological factors affecting pulmonary anthropo-radiometry

    International Nuclear Information System (INIS)

    As existing phantoms used for the calibration of dosimetry measurements, notably in anthropo-radiometry, exhibit a poor anatomic realism because of their crude geometries, compositions and densities, and some other drawbacks, the authors, within the frame of improvement of calibration techniques, report the combined use of Mesh and NURBS-type phantoms (Non Uniform Rational B-Splines) which allow smooth shapes and finer geometries to be replicated. More precisely, they report the application of this type of phantoms to the modelling of a thorax and of a ribcage. They describe the protocols used to generate these phantoms and how some variations are introduced to take morphological characteristics (for example a female thorax) as well as various gamma ray distributions into account. Results are discussed in terms of validation of phantoms, and morphology variation

  3. Revisiting the Effect of Anthropomorphizing a Social Cause Campaign.

    Directory of Open Access Journals (Sweden)

    Lisa A Williams

    Full Text Available Recent research suggests that anthropomorphism can be harnessed as a tool to boost intentions to comply with social cause campaigns. Drawing on the human tendency to extend moral concern to entities portrayed as humanlike, it has been argued that adding personified features to a social campaign elevates anticipated guilt at failing to comply, and this subsequently boosts intentions to comply with that campaign. The present research aimed to extend extant research by disentangling the effects of emotional and non-emotional anthropomorphism, and differentiating amongst other emotional mechanisms of the anthropomorphism-compliance effect (namely, anticipated pride and anticipated regret. Experiment 1 (N = 294 compared the effectiveness of positive, negative, and emotionally-neutral anthropomorphized campaign posters for boosting campaign compliance intentions against non-anthropomorphized posters. We also measured potential mechanisms including anticipated guilt, regret, and pride. Results failed to support the anthropomorphism-compliance effect, and no changes in anticipated emotion according to anthropomorphism emerged. Experiments 2 (N = 150 and 3 (N = 196 represented further tests of the anthropomorphism-compliance effect. Despite high statistical power and efforts to closely replicate the conditions under which the anthropomorphism-compliance effect had been previously observed, no differences in compliance intention or anticipated emotion according to anthropomorphism emerged. A meta-analysis of the effects of anthropomorphism on compliance and anticipated emotion across the three experiments revealed effect size estimates that did not differ significantly from zero. The results of these three experiments suggest that the anthropomorphism-compliance effect is fragile and perhaps subject to contextual and idiographic influences. Thus, this research provides important insight and impetus for future research on the applied and theoretical

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

    International Nuclear Information System (INIS)

    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

  5. 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

  6. X-ray diagnostics of thorax diseases; Roentgendiagnostik von Thoraxerkrankungen. Von der Deskription zur Diagnose

    Energy Technology Data Exchange (ETDEWEB)

    Kulke, H.M. [Wuerzburg Univ. (Germany). Universitaetsklinikum

    2013-11-01

    The book on X-ray diagnostics of thorax diseases covers the following issues: diagnostic procedures, inflammatory thorax diseases, malign thorax diseases, heart and large blood vessels, hear insufficiency, pulmonary congestion, pulmonary edema, interstitial pulmonary diseases, intensive care and traumatology.

  7. Phantom depth and stable phantom exactness

    OpenAIRE

    Epstein, Neil M.

    2005-01-01

    Phantom depth, phantom nonzerodivisors, and phantom exact sequences are analogues of the non-"phantom" notions which have been useful in tackling the (very difficult) localization problem in tight closure theory. In the present paper, these notions are developed further and partially reworked. For instance, although no analogue of a long exact sequence arises from a short stably phantom exact sequence of complexes, we provide a method for recovering the kind of information obtainable from suc...

  8. Bioassay Phantoms Using Medical Images and Computer Aided Manufacturing

    International Nuclear Information System (INIS)

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

  9. Bioassay Phantoms Using Medical Images and Computer Aided Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Dr. X. Geroge Xu

    2011-01-28

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

  10. Evaluation of radiation dose to anthropomorphic paediatric models from positron-emitting labelled tracers

    International Nuclear Information System (INIS)

    PET uses specific molecules labelled with positron-emitting radionuclides to provide valuable biochemical and physiological information. However, the administration of radiotracers to patients exposes them to low-dose ionizing radiation, which is a concern in the paediatric population since children are at a higher cancer risk from radiation exposure than adults. Therefore, radiation dosimety calculations for commonly used positron-emitting radiotracers in the paediatric population are highly desired. We evaluate the absorbed dose and effective dose for 19 positron-emitting labelled radiotracers in anthropomorphic paediatric models including the newborn, 1-, 5-, 10- and 15-year-old male and female. This is achieved using pre-calculated S-values of positron-emitting radionuclides of UF-NCI paediatric phantoms and published biokinetic data for various radiotracers. The influence of the type of anthropomorphic model, tissue weight factors and direct human- versus mouse-derived biokinetic data on the effective dose for paediatric phantoms was also evaluated. In the case of 18F-FDG, dosimetry calculations of reference paediatric patients from various dose regimens were also calculated. Among the considered radiotracers, 18F-FBPA and 15O-water resulted in the highest and lowest effective dose in the paediatric phantoms, respectively. The ICRP 103 updated tissue-weighting factors decrease the effective dose in most cases. Substantial differences of radiation dose were observed between direct human- versus mouse-derived biokinetic data. Moreover, the effect of using voxel- versus MIRD-type models on the calculation of the effective dose was also studied. The generated database of absorbed organ dose and effective dose for various positron-emitting labelled radiotracers using new generation computational models and the new ICRP tissue-weighting factors can be used for the assessment of radiation risks to paediatric patients in clinical practice. This work also contributes

  11. Evaluation of radiation dose to anthropomorphic paediatric models from positron-emitting labelled tracers

    Science.gov (United States)

    Xie, Tianwu; Zaidi, Habib

    2014-03-01

    PET uses specific molecules labelled with positron-emitting radionuclides to provide valuable biochemical and physiological information. However, the administration of radiotracers to patients exposes them to low-dose ionizing radiation, which is a concern in the paediatric population since children are at a higher cancer risk from radiation exposure than adults. Therefore, radiation dosimety calculations for commonly used positron-emitting radiotracers in the paediatric population are highly desired. We evaluate the absorbed dose and effective dose for 19 positron-emitting labelled radiotracers in anthropomorphic paediatric models including the newborn, 1-, 5-, 10- and 15-year-old male and female. This is achieved using pre-calculated S-values of positron-emitting radionuclides of UF-NCI paediatric phantoms and published biokinetic data for various radiotracers. The influence of the type of anthropomorphic model, tissue weight factors and direct human- versus mouse-derived biokinetic data on the effective dose for paediatric phantoms was also evaluated. In the case of 18F-FDG, dosimetry calculations of reference paediatric patients from various dose regimens were also calculated. Among the considered radiotracers, 18F-FBPA and 15O-water resulted in the highest and lowest effective dose in the paediatric phantoms, respectively. The ICRP 103 updated tissue-weighting factors decrease the effective dose in most cases. Substantial differences of radiation dose were observed between direct human- versus mouse-derived biokinetic data. Moreover, the effect of using voxel- versus MIRD-type models on the calculation of the effective dose was also studied. The generated database of absorbed organ dose and effective dose for various positron-emitting labelled radiotracers using new generation computational models and the new ICRP tissue-weighting factors can be used for the assessment of radiation risks to paediatric patients in clinical practice. This work also contributes

  12. Children's Anthropomorphic and Anthropocentric Ideas about Micro-Organisms

    Science.gov (United States)

    Byrne, Jenny; Grace, Marcus; Hanley, Pam

    2009-01-01

    Different views exist about whether anthropomorphic ideas assist or hinder learning in biology. This paper discusses the anthropomorphic and anthropocentric ideas children have about micro-organisms, and whether they affect their understanding. The research was carried out in primary and secondary schools in the South of England and involved 414…

  13. Design of Experiments for Calibration of Planar Anthropomorphic Manipulators

    OpenAIRE

    Klimchik, Alexandr; Wu, Yier; Caro, Stéphane; Pashkevich, Anatol

    2011-01-01

    The paper presents a novel technique for the design of optimal calibration experiments for a planar anthropomorphic manipulator with n degrees of freedom. Proposed approach for selection of manipulator configurations allows essentially improving calibration accuracy and reducing parameter identification errors. The results are illustrated by application examples that deal with typical anthropomorphic manipulators.

  14. Asbestos-related diseases of the thorax

    International Nuclear Information System (INIS)

    Asbestos fibers can lead to pulmonary fibrosis, thickening of the pleura and malignancies. These pathologic changes are possible rather than determinate and depend on the type of asbestos fiber, length of exposure to fibers and individual factors. In Germany asbestos fibers were widely used until 1993. Worldwide, there is currently no general ban on the use of asbestos. The leading cause of asbestos-related diseases is occupational exposure. Due to a long latency period the appearance of such diseases may be delayed for more than 40 years so that the final number of cases has not yet been reached. Occupationally-derived asbestos-related diseases of the thorax are asbestosis, asbestos-related benign pleurisy and malignant pleural mesothelioma. Bronchial carcinoma can also be caused by asbestos exposure. For proof of occupational exposure, radiologists are required to report the presence of characteristic findings. The detection, in particular by chest X-ray and high resolution computed tomography (HRCT), requires high quality images and standardized evaluation. The standardized ILO classification and the semi-quantitative HRCT coding are medical findings on which statutory registration criteria are based. (orig.)

  15. Dose in thorax X-ray; Dosis en radiografia de torax

    Energy Technology Data Exchange (ETDEWEB)

    Pinedo S, A.; Hernandez O, M.; Duran M, H. A.; Gonzalez G, R.; Guerra M, J. A.; Hernandez D, V. M.; Salas L, M. A.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Rivera M, T. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria 694, 11500 Mexico D. F. (Mexico); Azorin N, J. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco 186, 09340 Mexico D. F. (Mexico)], e-mail: lare_56@hotmail.com

    2009-10-15

    The entrance dose that a patient receives during a radiological study of thorax was measured, these measures were realized with thermoluminescent dosemeters of CaSO{sub 4}:Dy, placed in paraffin phantom. The radiation control in diagnostic radiology should be an important element during each radiological procedure. Current studies suggest that even low dose of X-rays used in routine diagnostic procedures can give space to a small incidence of latent damaging effects in patient. The irradiation of thoracic region is more studied through the conventional radiology, method that continues occupying the first place like diagnostic in several pathologies it generates images of heart, lungs, spine, etc. As well as, allow to observe the location of catheters, subclavian s, nasogastric sound, endotracheal tubes and umbilical catheters. The dose magnitude that is received during the realization of this study type is not usually measured, since the main concern is to have a good image to make a good diagnostic. The measures were realized using equipment parameters that were defined on experience of radiologist technician. The work was realized in the living room 1 of X-rays service of General Hospital of Zone No. 1 of IMSS in Zacatecas. The obtained results demonstrated that irradiation field is not uniform and that in any point where the dose was measured it is not exceeded to that established by the Mexican Official Standard-157-SSA-1996 for a study of thorax X-ray. (Author)

  16. Dosimetry in thorax X-rays; Dosimetria en radiografia de torax

    Energy Technology Data Exchange (ETDEWEB)

    Pinedo S, A.; Hernandez O, M.; Duran M, H. A.; Gonzalez G, R.; Guerra M, J. A.; Salas L, M. A.; Vega C, H. R. [Unidad Academica de Estudios Nucleares, Universidad Autonoma de Zacatecas, Cipres 10, Fracc. La Penuela, 98000 Zacatecas (Mexico); Rivera M, T. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, IPN, Av. Legaria 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico); Azorin N, J. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico D. F. (Mexico)], e-mail: lare_56@hotmail.com

    2009-10-15

    The dose to the entrance of thorax during a radiological study has been measured in a phantom of paraffin and with thermoluminescent dosemeters. This work was realized in the living room 1 of the X-rays service of the General Hospital No. 1 IMSS in Zacatecas. For the study thermoluminescent dosemeters of CaSO{sub 4}:Dy were used. The irradiation of the thoracic region is the more studied through the conventional radiology, method that continues occupying the first place as diagnostic in diverse pathologies due to generates images of the heart, lungs, spine, etc. As well as can to observe the location of subclavian catheters, nasogastric sound, endotracheal tubes and umbilical catheters. The magnitude of the dose that is received during the realization of this study type is not usually measured, since the main concern is to have a good image to make a good diagnostic. The measurements were carried out using parameters of the equipment that were defined with base to the experience of the technical radiologist. It was found that the irradiation field is not uniform and that in any point where the dose was measured it is not exceeded the 7 mGy settled by the Mexican Official Standard-157-SSA-1996 for a thorax study. (author)

  17. Crossing the phantom divide without phantom matter

    OpenAIRE

    Chimento, L.; Lazkoz, R.; Maartens, Roy; Quiros, I.

    2006-01-01

    A class of braneworld models can lead to phantom-like acceleration of the late universe, but without the need for any phantom matter. In the simplest models, the universe contains only cold dark matter and a cosmological constant. We generalize these models by introducing a quintessence field. The new feature in our models is that quintessence leads to a crossing of the phantom divide, $w=-1$. This is a purely gravitational effect, and there is no phantom instability. Furthermore, the Hubble ...

  18. Humanizing machines: Anthropomorphization of slot machines increases gambling.

    Science.gov (United States)

    Riva, Paolo; Sacchi, Simona; Brambilla, Marco

    2015-12-01

    Do people gamble more on slot machines if they think that they are playing against humanlike minds rather than mathematical algorithms? Research has shown that people have a strong cognitive tendency to imbue humanlike mental states to nonhuman entities (i.e., anthropomorphism). The present research tested whether anthropomorphizing slot machines would increase gambling. Four studies manipulated slot machine anthropomorphization and found that exposing people to an anthropomorphized description of a slot machine increased gambling behavior and reduced gambling outcomes. Such findings emerged using tasks that focused on gambling behavior (Studies 1 to 3) as well as in experimental paradigms that included gambling outcomes (Studies 2 to 4). We found that gambling outcomes decrease because participants primed with the anthropomorphic slot machine gambled more (Study 4). Furthermore, we found that high-arousal positive emotions (e.g., feeling excited) played a role in the effect of anthropomorphism on gambling behavior (Studies 3 and 4). Our research indicates that the psychological process of gambling-machine anthropomorphism can be advantageous for the gaming industry; however, this may come at great expense for gamblers' (and their families') economic resources and psychological well-being. PMID:26322589

  19. The use of zeolites to generate PET phantoms for the validation of quantification strategies in oncology

    Energy Technology Data Exchange (ETDEWEB)

    Zito, Felicia; De Bernardi, Elisabetta; Soffientini, Chiara; Canzi, Cristina; Casati, Rosangela; Gerundini, Paolo; Baselli, Giuseppe [Nuclear Medicine Department, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, via Francesco Sforza 35, 20122 Milan (Italy); Bioengineering Department, Politecnico di Milano, piazza Leonardo da Vinci 32, 20133 Milan (Italy) and Tecnomed Foundation, University of Milano-Bicocca, via Pergolesi 33, 20900 Monza (Italy); Bioengineering Department, Politecnico di Milano, piazza Leonardo da Vinci 32, 20133 Milan (Italy); Nuclear Medicine Department, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, via Francesco Sforza 35, 20122 Milan (Italy); Bioengineering Department, Politecnico di Milano, piazza Leonardo da Vinci 32, 20133 Milan (Italy)

    2012-09-15

    Purpose: In recent years, segmentation algorithms and activity quantification methods have been proposed for oncological {sup 18}F-fluorodeoxyglucose (FDG) PET. A full assessment of these algorithms, necessary for a clinical transfer, requires a validation on data sets provided with a reliable ground truth as to the imaged activity distribution, which must be as realistic as possible. The aim of this work is to propose a strategy to simulate lesions of uniform uptake and irregular shape in an anthropomorphic phantom, with the possibility to easily obtain a ground truth as to lesion activity and borders. Methods: Lesions were simulated with samples of clinoptilolite, a family of natural zeolites of irregular shape, able to absorb aqueous solutions of {sup 18}F-FDG, available in a wide size range, and nontoxic. Zeolites were soaked in solutions of {sup 18}F-FDG for increasing times up to 120 min and their absorptive properties were characterized as function of soaking duration, solution concentration, and zeolite dry weight. Saturated zeolites were wrapped in Parafilm, positioned inside an Alderson thorax-abdomen phantom and imaged with a PET-CT scanner. The ground truth for the activity distribution of each zeolite was obtained by segmenting high-resolution finely aligned CT images, on the basis of independently obtained volume measurements. The fine alignment between CT and PET was validated by comparing the CT-derived ground truth to a set of zeolites' PET threshold segmentations in terms of Dice index and volume error. Results: The soaking time necessary to achieve saturation increases with zeolite dry weight, with a maximum of about 90 min for the largest sample. At saturation, a linear dependence of the uptake normalized to the solution concentration on zeolite dry weight (R{sup 2}= 0.988), as well as a uniform distribution of the activity over the entire zeolite volume from PET imaging were demonstrated. These findings indicate that the {sup 18}F

  20. Utilization of a homogeneous phantom of extremities for radiographic images standardization

    International Nuclear Information System (INIS)

    This work aims at the utilization of a homogeneous phantom, allowing to simulate absorption and scattering of the radiation next to a patient's extremity. Homogeneous phantom will be used in the time-scale sensitometric method to evaluate the sensitivity of screen-film systems. These radiographic techniques will be applied, in the future, to anthropomorphic phantom for extremities, leading to the achievement of a better radiographic technique, with a lesser dose for the patient and the reduction of cost of a radiodiagnostic job. By standardizing the radiographic techniques, it is possible to decrease the number of rejected films and reduce the charge of the equipment tube. (author)

  1. FlexyDos3D: a deformable anthropomorphic 3D radiation dosimeter: radiation properties

    DEFF Research Database (Denmark)

    De Deene, Yves; Skyt, Peter Sandegaard; Hill, Robin;

    2015-01-01

    registration software.A new three dimensional anthropomorphically shaped flexible dosimeter, further called 'FlexyDos3D', has been constructed and a new fast optical scanning method has been implemented that enables scanning of irregular shaped dosimeters. The FlexyDos3D phantom can be actuated and deformed...... during the actual treatment. FlexyDos3D offers the additional advantage that it is easy to fabricate, is non-toxic and can be molded in an arbitrary shape with high geometrical precision.The dosimeter formulation has been optimized in terms of dose sensitivity. The influence of the casting material and......Three dimensional radiation dosimetry has received growing interest with the implementation of highly conformal radiotherapy treatments. The radiotherapy community faces new challenges with the commissioning of image guided and image gated radiotherapy treatments (IGRT) and deformable image...

  2. HIT anthropomorphic robotic hand and finger motion control

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Nowadays many anthropomorphic robotic hands have been put forward. These hands emphasize different aspects according to their applications. HIT Anthropomorphic Robotic Hand (ARhand) is a simple,lightweight and dexterous design per the requirements of anthropomorphic robots. Underactuated self-adaptive theory is adopted to decrease the number of motors and weight. The fingers of HIT ARhand with multi phalanges have the same size as those of an adult hand. Force control is realized with the position sensor, joint torque sensor and fingertip torque sensor. From the 3D model, the whole hand, with the low power consumption DSP control board integrated in it, will weigh only 500 g. It will be assembled on a BIT-Anthropomorphic Robot.

  3. Asbestos-related diseases of the thorax; Asbestverursachte Veraenderungen am Thorax

    Energy Technology Data Exchange (ETDEWEB)

    Hieckel, H.G. [Evangelische Lungenklinik Berlin (Germany); Hering, K.G. [Knappschaftskrankenhaus Dortmund (Germany)

    2010-07-15

    Asbestos fibers can lead to pulmonary fibrosis, thickening of the pleura and malignancies. These pathologic changes are possible rather than determinate and depend on the type of asbestos fiber, length of exposure to fibers and individual factors. In Germany asbestos fibers were widely used until 1993. Worldwide, there is currently no general ban on the use of asbestos. The leading cause of asbestos-related diseases is occupational exposure. Due to a long latency period the appearance of such diseases may be delayed for more than 40 years so that the final number of cases has not yet been reached. Occupationally-derived asbestos-related diseases of the thorax are asbestosis, asbestos-related benign pleurisy and malignant pleural mesothelioma. Bronchial carcinoma can also be caused by asbestos exposure. For proof of occupational exposure, radiologists are required to report the presence of characteristic findings. The detection, in particular by chest X-ray and high resolution computed tomography (HRCT), requires high quality images and standardized evaluation. The standardized ILO classification and the semi-quantitative HRCT coding are medical findings on which statutory registration criteria are based. (orig.) [German] Asbestfasern koennen zu einer Lungenfibrose, zu Verdickungen der Pleura und zu Malignomen fuehren. Diese pathologischen Veraenderungen sind fakultativ und abhaengig von der Asbestart, der Dauer der Exposition und von individuellen Faktoren. Asbest fand bis 1993 in Deutschland breiten Einsatz. Weltweit besteht noch kein Verbot. Mehrheitlich sind asbestbedingte Erkrankungen Folgen beruflicher Expositionen. Bis zu ihrem Auftreten liegen lange Latenzzeiten bis ueber 40 Jahre, sodass das Maximum noch nicht erreicht ist. Asbestverursachte Berufserkrankungen am Thorax sind die Asbestose und asbestverursachte benigne Pleuraerkrankungen sowie das maligne Pleuramesotheliom. Bronchialkarzinome koennen asbestverursacht sein. Zur Beweisfuehrung wird von der

  4. Optimization and objective and subjective analysis of thorax image for computerized radiology

    International Nuclear Information System (INIS)

    This research aimed at optimizing computational chest radiographic images (in previous posterior projection-PA). To this end, we used a homogeneous patient equivalent phantom in Computational Imaging System calibration, in order to obtain a satisfactory noise signal relation for a diagnosis, adjusting to a minimum dose received by the patient. The techniques have been applied in an anthropomorphic phantom (RANDO). The images obtained were evaluated by a radiologist, which identified the best image to determine possible pathologies (fracture or pneumonia). The technique were quantified objectively (Detective Quantum Efficiency - DQE, Modulation Transfer Function MTF, Noise Power Spectrum, NPS). Comparing optimized techniques with the clinical routine, it is concluded that all provide doses below reference levels. However the choice of the best technique for viewing possible pneumonia and/or fracture, was determined based on the first 3D (Dose, Diagnostic, Dollar) and regarded as gold standard. This image presented a reduction of dose and loading of tube around 70.5% and 80% respectively when compared with the clinical routine

  5. A Global Obstacle-avoidance Map for Anthropomorphic Arms

    Directory of Open Access Journals (Sweden)

    Cheng Fang

    2014-07-01

    Full Text Available More and more humanoid robots are used in human society, and they face a wide variety of complicated manipulation tasks, which are mainly to be achieved by their anthropomorphic arms. Obstacle avoidance for the anthropomorphic arm must be a fundamental consideration to guarantee the successful implementation of these tasks. Different from traditional methods searching for feasible or optimal collision-free solutions for the anthropomorphic arm, a global obstacle- avoidance map for the whole arm is proposed to indicate the complete set of feasible solutions. In this map, the motion of the arm can be appropriately planned to intuitively control the configuration of the arm in motion. First, the cubic spline function is adopted to interpolate some well-chosen path points to generate a smooth collision-free path for the wrist of the anthropomorphic arm. Second, based on the path function of the wrist, the time and the self-rotation angle of the arm about the “shoulder-wrist” axis are used to parameterize all possible configurations of the arm so that a global two- dimensional map considering the obstacle avoidance can be established. Subsequently, a collision-free self-rotation angle profile of the arm can be well planned. Finally, the joint trajectories of a specific anthropomorphic arm, which correspond to the planned path of the wrist and self-rotation angle profile of the arm, can be solved on the basis of the general kinematic analysis of the anthropomorphic arm, and the specific structure. Several simulations are conducted to verify that the proposed collision-free motion planning method for anthropomorphic arms has some advantages and can be regarded as a convenient and intuitive tool to control the configuration of the anthropomorphic arm in motion, without collision with obstacles in its surroundings.

  6. A sub-domain based regularization method with prior information for human thorax imaging using electrical impedance tomography

    Science.gov (United States)

    In Kang, Suk; Khambampati, Anil Kumar; Jeon, Min Ho; Kim, Bong Seok; Kim, Kyung Youn

    2016-02-01

    Electrical impedance tomography (EIT) is a non-invasive imaging technique that can be used as a bed-side monitoring tool for human thorax imaging. EIT has high temporal resolution characteristics but at the same time it suffers from poor spatial resolution due to ill-posedness of the inverse problem. Often regularization methods are used as a penalty term in the cost function to stabilize the sudden changes in resistivity. In human thorax monitoring, with conventional regularization methods employing Tikhonov type regularization, the reconstructed image is smoothed between the heart and the lungs, that is, it makes it difficult to distinguish the exact boundaries of the lungs and the heart. Sometimes, obtaining structural information of the object prior to this can be incorporated into the regularization method to improve the spatial resolution along with helping create clear and distinct boundaries between the objects. However, the boundary of the heart is changed rapidly due to the cardiac cycle hence there is no information concerning the exact boundary of the heart. Therefore, to improve the spatial resolution for human thorax monitoring during the cardiac cycle, in this paper, a sub-domain based regularization method is proposed assuming the lungs and part of background region is known. In the proposed method, the regularization matrix is modified anisotropically to include sub-domains as prior information, and the regularization parameter is assigned with different weights to each sub-domain. Numerical simulations and phantom experiments for 2D human thorax monitoring are performed to evaluate the performance of the proposed regularization method. The results show a better reconstruction performance with the proposed regularization method.

  7. A sub-domain based regularization method with prior information for human thorax imaging using electrical impedance tomography

    International Nuclear Information System (INIS)

    Electrical impedance tomography (EIT) is a non-invasive imaging technique that can be used as a bed-side monitoring tool for human thorax imaging. EIT has high temporal resolution characteristics but at the same time it suffers from poor spatial resolution due to ill-posedness of the inverse problem. Often regularization methods are used as a penalty term in the cost function to stabilize the sudden changes in resistivity. In human thorax monitoring, with conventional regularization methods employing Tikhonov type regularization, the reconstructed image is smoothed between the heart and the lungs, that is, it makes it difficult to distinguish the exact boundaries of the lungs and the heart. Sometimes, obtaining structural information of the object prior to this can be incorporated into the regularization method to improve the spatial resolution along with helping create clear and distinct boundaries between the objects. However, the boundary of the heart is changed rapidly due to the cardiac cycle hence there is no information concerning the exact boundary of the heart. Therefore, to improve the spatial resolution for human thorax monitoring during the cardiac cycle, in this paper, a sub-domain based regularization method is proposed assuming the lungs and part of background region is known. In the proposed method, the regularization matrix is modified anisotropically to include sub-domains as prior information, and the regularization parameter is assigned with different weights to each sub-domain. Numerical simulations and phantom experiments for 2D human thorax monitoring are performed to evaluate the performance of the proposed regularization method. The results show a better reconstruction performance with the proposed regularization method. (paper)

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

    Energy Technology Data Exchange (ETDEWEB)

    Long, Daniel J.; Lee, Choonsik; Tien, Christopher; Fisher, Ryan; Hoerner, Matthew R.; Hintenlang, David; Bolch, Wesley E. [J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida 32611-6131 (United States); National Cancer Institute, National Institute of Health, Bethesda, Maryland 20892-1502 (United States); J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida 32611-6131 (United States); Department of Radiology, University of Florida, Gainesville, Florida 32610-0374 (United States); J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida 32611-6131 (United States)

    2013-01-15

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

  9. Development of a breathing phantom for comparison of two breathing surrogates systems in 4DCT-imaging

    OpenAIRE

    Vásquez Torres, Andrés Camilo

    2011-01-01

    Die vierdimensionale Computertomographie (4D-CT) benötigt ein Monitorsignal für die Atmung. Verschiede Systeme sind zur Zeit verfügbar, aber um diese Systeme unter realistischen Bedingungen zu testen, ist ein Phantom mit einem beweglichen Zielobjekt und einer verformbaren äußeren Kontur erforderlich. Ein anthropomorphes Phantom wurde entwickelt und getestet. Die Atmungsbewegung eines Probanden wurde zusammen mit einer synchronen und asynchronen Bewegungen eines Lungentumors reproduziert. Das ...

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

    International Nuclear Information System (INIS)

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

  11. Potentiation of chemically induced lung fibrosis by thorax irradiation

    International Nuclear Information System (INIS)

    Intraperitoneal injection of butylated hydroxytoluene (BHT) causes epithelial cell death, followed 2 to 4 days later by extensive proliferation of type II alveolar cells in mouse lung. Five to 8 days after BHT, most dividing cells are capillary endothelial cells or interstitial cells. In animials that were exposed to 200 rad thorax irradiation immediately or 1 day after BHT, lung hydroxyproline was increased 2 weeks later. The response was dose dependent, and the interaction between BHT and thorax irradiation was synergistic. Light microscopy showed abnormal accumulation of collagen in the alveolar septa. Lung hydroxyproline was not increased in animals that were irradiated 6 days after BHT, compared to animals treated with BHT alone. We concluded that fibrosis develops if lung is damaged by a blood-borne agent and radiation to the thorax occurs at a time when it may compromise alveolar reepithelialization. Exposure to x-rays during proliferation of capillary endothelial cells or interstitial cells does not enhance development of fibrosis

  12. Mosaic morphology in the thorax of Australopithecus sediba.

    Science.gov (United States)

    Schmid, Peter; Churchill, Steven E; Nalla, Shahed; Weissen, Eveline; Carlson, Kristian J; de Ruiter, Darryl J; Berger, Lee R

    2013-04-12

    The shape of the thorax of early hominins has been a point of contention for more than 30 years. Owing to the generally fragmentary nature of fossil hominin ribs, few specimens have been recovered that have rib remains complete enough to allow accurate reassembly of thoracic shape, thus leaving open the question of when the cylindrical-shaped chest of humans and their immediate ancestors evolved. The ribs of Australopithecus sediba exhibit a mediolaterally narrow, ape-like upper thoracic shape, which is unlike the broad upper thorax of Homo that has been related to the locomotor pattern of endurance walking and running. The lower thorax, however, appears less laterally flared than that of apes and more closely approximates the morphology found in humans. PMID:23580537

  13. Flexibility and control of thorax deformation during hawkmoth flight.

    Science.gov (United States)

    Ando, Noriyasu; Kanzaki, Ryohei

    2016-01-01

    The interaction between neuromuscular systems and body mechanics plays an important role in the production of coordinated movements in animals. Lepidopteran insects move their wings by distortion of the thorax structure via the indirect flight muscles (IFMs), which are activated by neural signals at every stroke. However, how the action of these muscles affects thorax deformation and wing kinematics is poorly understood. We measured the deformation of the dorsal thorax (mesonotum) of tethered flying hawkmoths, Agrius convolvuli, using a high-speed laser profilometer combined with simultaneous recordings of electromyograms and wing kinematics. We observed that locally amplified mesonotum deformation near the wing hinges ensures sufficient wing movement. Furthermore, phase asymmetry in IFM activity leads to phase asymmetry in mesonotum oscillations and wingbeats. Our results revealed the flexibility and controllability of the single structure of the mesonotum by neurogenic action of the IFMs. PMID:26740560

  14. Reconstruction of voxel phantoms for skin dosimetry

    International Nuclear Information System (INIS)

    Radiotherapy is a therapeutic modality that utilizes ionizing radiation for the destruction of neoplastic human cells. One of the requirements for this treatment methodology success lays on the appropriate use of planning systems, which performs, among other information, the patient's dose distribution estimate. Nowadays, transport codes have been providing huge subsidies to these planning systems, once it enables specific and accurate patient organ and tissue dosimetry. The model utilized by these codes to describe the human anatomy in a realistic way is known as voxel phantoms, which are represented by discrete volume elements (voxels) directly associated to tomographic data. Nowadays, voxel phantoms doable of being inserted and processed by the transport code MCNP (Monte Carlo N-Particle) presents a 3-4 mm image resolution; however, such resolution limits some thin body structure discrimination, such as skin. In this context, this work proposes a calculus routine that discriminates this region with thickness and localization in the voxel phantoms similar to the real, leading to an accurate dosimetric skin dose assessment by the MCNP code. Moreover, this methodology consists in manipulating the voxel phantoms volume elements by segmenting and subdividing it in different skin thickness. In addition to validate the skin dose calculated data, a set of experimental evaluations with thermoluminescent dosimeters were performed in an anthropomorphic phantom. Due to significant differences observed on the dose distribution of several skin representations, it was found that is important to discriminate the skin thickness similar to the real. The presented methodology is useful to obtain an accurate skin dosimetric evaluation for several radiotherapy procedures, with particular interest on the electron beam radiotherapy, in which highlights the whole body irradiation therapy (TSET), a procedure under implementation at the Hospital das Clinicas da Faculdade de Medicina da

  15. Membership function used to construction of a hand homogeneous phantom

    International Nuclear Information System (INIS)

    Fractures and dislocations of the hand are some injuries most frequently encountered in trauma of the musculoskeletal system. In evaluating these lesions, in addition to physical examination, radiography, in at least two incidents, is the investigation of choice, and rarely is necessary the help of other images to establish the diagnosis and treatment. The image quality of X-ray examination is therefore essential. In this study, a homogeneous phantom hand was developed to be used in the optimization of images from hand using computed radiography system process. In this procedure were quantified thicknesses of different tissues that constitute an anthropomorphic phantom hand. To perform the classification and quantification of tissue was applied membership functions for histograms of CT scans. The same procedure was adopted for retrospective examinations of 30 patients of the Hospital das Clinicas, Botucatu Medicine School, UNESP (HCFMB-UNESP). The results showed agreement between the thicknesses of tissues that make up the anthropomorphic phantom and sampling of patients, presenting variations between 12.63% and 6.48% for soft tissue and bone, respectively. (author)

  16. 49 CFR 572.195 - Thorax with arm.

    Science.gov (United States)

    2010-10-01

    ... accelerometers as specified in 49 CFR 572.200(d), and deflection potentiometers for the thorax and shoulder as... environment as specified in 49 CFR 572.200(j). (2) Seat the dummy, outfitted with the torso jacket (180-3450... spine box. (8) The impactor is specified in 49 CFR 572.200(a). (9) The impactor is guided, if needed,...

  17. Training for thorax diagnostics. Systematic cardiopulmonary image analysis

    International Nuclear Information System (INIS)

    The training book on thorax diagnostics using image analysis is supposed to be a supplement to the usual textbooks based on comprehensive experiences of radiologists. The covered issues are the following: heart insufficiency, acute/ chronic bronchitis and pulmonary emphysema; pneumonia and tuberculosis; bronchial carcinoma; lung fibrosis, sarcoidosis and pneumoconiosis, pleural effusion and pneumothorax.

  18. Recurrent spontaneous pneumothorax after radiation therapy to the thorax

    Energy Technology Data Exchange (ETDEWEB)

    Twiford, T.W. Jr.; Zornoza, J.; Libshitz, H.I.

    1978-03-01

    Two patients who received radiation therapy to the thorax and who developed recurrent spontaneous pneumothoraces are presented. Patients with recurrent pneumothoraces secondary to radiation have not been described previously. Pleural changes secondary to radiation may contribute significantly to the complicated clinical course of these patients.

  19. Phantom limb pain

    Science.gov (United States)

    ... shooting pain Achy pain Burning pain Cramping pain Phantom limb pain will lessen over time for most people. ... Elsevier; 2012:chap 44. Bang MS, Jung SH. Phantom limb pain. In: Frontera, WR, Silver JK, eds. Essentials ...

  20. Variable curvature phantom

    International Nuclear Information System (INIS)

    The design of a variable curvature dosimetry phantom is briefly described. The phantom was developed to test the accuracy of the dose modification algorithms used to estimate dose distributions inside patient contours. 1 fig

  1. Evaluation of the effective dose in an anthropomorphic phantom in radiation emergencies

    International Nuclear Information System (INIS)

    This study aims to perform a modeling of the human anatomy using Voxel models applied to Monte Carlo code and the Visual Monte Carlo software, simulating irradiation of the human body, so you can make the dose assessment in individuals who have been exposed to any external ionizing radiation source. Making the future, an assessment of both results with limits of validity of TECDOC-1162 expressions of the IAEA in case of point source

  2. Pediatric radiation dosimetry for positron-emitting radionuclides using anthropomorphic phantoms

    NARCIS (Netherlands)

    Xie, Tianwu; Bolch, Wesley E.; Lee, Choonsik; Zaidi, Habib

    2013-01-01

    Purpose: Positron emission tomography (PET) plays an important role in the diagnosis, staging, treatment, and surveillance of clinically localized diseases. Combined PET/CT imaging exhibits significantly higher sensitivity, specificity, and accuracy than conventional imaging when it comes to detecti

  3. Characterization of MOSFET dosimeters for low-dose measurements in maxillofacial anthropomorphic phantoms

    NARCIS (Netherlands)

    J.H. Koivisto; J.E. Wolff; T. Kiljunen; D. Schulze; M. Kortesniemi

    2015-01-01

    The aims of this study were to characterize reinforced metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters to assess the measurement uncertainty, single exposure low-dose limit with acceptable accuracy, and the number of exposures required to attain the corresponding limit of the t

  4. Phantom Black Holes

    OpenAIRE

    Gao, C. J.; Zhang, S. N.

    2006-01-01

    The exact solutions of electrically charged phantom black holes with the cosmological constant are constructed. They are labelled by the mass, the electrical charge, the cosmological constant and the coupling constant between the phantom and the Maxwell field. It is found that the phantom has important consequences on the properties of black holes. In particular, the extremal charged phantom black holes can never be achieved and so the third law of thermodynamics for black holes still holds. ...

  5. More on phantom bidding

    OpenAIRE

    Ruqu Wang; Parimal Kanti Bag; Emim Murat Dinlersoz

    2000-01-01

    A phantom bidding model is analyzed for a sale auction. The following questions are addressed: the effects of phantom bidding on overall social welfare and buyers' profits. It is shown that social welfare may increase or decrease as the auctioneer switches from the fixed reserve price policy to phantom bidding. The buyers' profits will increase whenever social welfare increases.

  6. Blowfly flight and optic flow I. Thorax kinematics and flight dynamics

    NARCIS (Netherlands)

    Schilstra, C; Van Hateren, JH

    1999-01-01

    The motion of the thorax of the blowfly Calliphora vicina was measured during cruising flight inside a cage measuring 40 cmx40 cmx40 cm, Sensor coils mounted on the thorax picked up externally generated magnetic fields and yielded measurements of the position and orientation of the thorax with a res

  7. Blowfly Flight and Optic Flow. I. Thorax Kinematics and Flight Dynamics

    NARCIS (Netherlands)

    Schilstra, C.; Hateren, J.H. van

    1999-01-01

    The motion of the thorax of the blowfly Calliphora vicina was measured during cruising flight inside a cage measuring 40cm×40cm×40 cm. Sensor coils mounted on the thorax picked up externally generated magnetic fields and yielded measurements of the position and orientation of the thorax with a resol

  8. Phantom maps and chromatic phantom maps

    OpenAIRE

    Christensen, J. Daniel; Hovey, Mark

    1998-01-01

    In the first part, we determine conditions on spectra X and Y under which either every map from X to Y is phantom, or no nonzero maps are. We also address the question of whether such all or nothing behaviour is preserved when X is replaced with V smash X for V finite. In the second part, we introduce chromatic phantom maps. A map is n-phantom if it is null when restricted to finite spectra of type at least n. We define divisibility and finite type conditions which are suitable for studying n...

  9. Evaluation of organ doses in adult and paediatric CT examinations based on Monte Carlo simulations and in-phantom dosimetry

    International Nuclear Information System (INIS)

    The aim of this study was to validate the computed tomography dose index (CTDI) and organ doses evaluated by Monte Carlo simulations through comparisons with doses evaluated by in-phantom dosimetry. Organ doses were measured with radio-photoluminescence glass dosemeter (RGD) set at various organ positions within adult and 1-y-old anthropomorphic phantoms. For the dose simulations, the X-ray spectrum and bow-tie filter shape of a CT scanner were estimated and 3D voxelised data of the CTDI and anthropomorphic phantoms from the acquired CT images were derived. Organ dose simulations and measurements were performed with chest and abdomen -pelvis CT examination scan parameters. Relative differences between the simulated and measured doses were within 5 % for the volume CTDI and 13 % for organ doses for organs within the scan range in adult and paediatric CT examinations. The simulation results were considered to be in good agreement with the measured doses. (authors)

  10. Evaluation of organ doses in adult and paediatric CT examinations based on Monte Carlo simulations and in-phantom dosimetry.

    Science.gov (United States)

    Fujii, K; Nomura, K; Muramatsu, Y; Takahashi, K; Obara, S; Akahane, K; Satake, M

    2015-07-01

    The aim of this study was to validate the computed tomography dose index (CTDI) and organ doses evaluated by Monte Carlo simulations through comparisons with doses evaluated by in-phantom dosimetry. Organ doses were measured with radio-photoluminescence glass dosemeter (RGD) set at various organ positions within adult and 1-y-old anthropomorphic phantoms. For the dose simulations, the X-ray spectrum and bow-tie filter shape of a CT scanner were estimated and 3D voxelised data of the CTDI and anthropomorphic phantoms from the acquired CT images were derived. Organ dose simulations and measurements were performed with chest and abdomen-pelvis CT examination scan parameters. Relative differences between the simulated and measured doses were within 5 % for the volume CTDI and 13 % for organ doses for organs within the scan range in adult and paediatric CT examinations. The simulation results were considered to be in good agreement with the measured doses. PMID:25848103

  11. Radiological diagnostics of abdomen and thorax. Image interpretation considering anatomical landmarks and clinical symptoms; Radiologische Diagnostik Abdomen und Thorax. Bildinterpretation unter Beruecksichtigung anatomischer Landmarken und klinischer Symptome

    Energy Technology Data Exchange (ETDEWEB)

    Krombach, Gabriele A. [Universitaetsklinikum Giessen (Germany). Klinik fuer Diagnostische und Interventionelle Radiologie; Mahnken, Andreas H. (ed.) [Universitaetsklinikum Marburg (Germany). Diagnostische und Interventionelle Radiologie

    2015-07-01

    The book on radiological diagnostics of abdomen and thorax - image interpretation considering anatomical landmarks and clinical symptoms - includes three chapters: (1) imaging of different parts of the body: thorax and abdomen. (II) Thorax: head and neck; mediastinum; heard and pericardium; large vessels; lungs and pleura; mamma. (III) Abdomen: liver; gall bladder and biliary tract; pancreas; gastrointestinal tract; spleen and lymphatic system; adrenal glands; kidneys and urinary tract; female pelvis; male pelvis.

  12. Evaluation of a method for correction of scatter radiation in thorax cone beam CT; Evaluation d'une methode de correction du rayonnement diffuse en tomographie du thorax avec faisceau conique

    Energy Technology Data Exchange (ETDEWEB)

    Rinkel, J.; Dinten, J.M. [CEA Grenoble (DTBS/STD), Lab. d' Electronique et de Technologie de l' Informatique, LETI, 38 (France); Esteve, F. [European Synchrotron Radiation Facility (ESRF), 38 - Grenoble (France)

    2004-07-01

    Purpose: Cone beam CT (CBCT) enables three-dimensional imaging with isotropic resolution. X-ray scatter estimation is a big challenge for quantitative CBCT imaging of thorax: scatter level is significantly higher on cone beam systems compared to collimated fan beam systems. The effects of this scattered radiation are cupping artefacts, streaks, and quantification inaccuracies. The beam stops conventional scatter estimation approach can be used for CBCT but leads to a significant increase in terms of dose and acquisition time. At CEA-LETI has been developed an original scatter management process without supplementary acquisition. Methods and Materials: This Analytical Plus Indexing-based method (API) of scatter correction in CBCT is based on scatter calibration through offline acquisitions with beam stops on lucite plates, combined to an analytical transformation issued from physical equations. This approach has been applied with success in bone densitometry and mammography. To evaluate this method in CBCT, acquisitions from a thorax phantom with and without beam stops have been performed. To compare different scatter correction approaches, Feldkamp algorithm has been applied on rough data corrected from scatter by API and by beam stops approaches. Results: The API method provides results in good agreement with the beam stops array approach, suppressing cupping artefact. Otherwise influence of the scatter correction method on the noise in the reconstructed images has been evaluated. Conclusion: The results indicate that the API method is effective for quantitative CBCT imaging of thorax. Compared to a beam stops array method it needs a lower x-ray dose and shortens acquisition time. (authors)

  13. Phantom appearance of non-phantom matter

    OpenAIRE

    Stefancic, Hrvoje

    2003-01-01

    Two cosmological models with non-phantom matter having the same expansion of the universe as phantom cosmologies are constructed. The first model is characterized by the evolving gravitational "constant" $G$ and a dark energy component with a non-conserved energy-momentum tensor. The second model includes two interacting components, the dark energy component and the matter component. Closed form solutions are obtained for the constant values of model parameters and constraints on the paramete...

  14. Physical phantom of typical Korean male for radiation protection purpose

    International Nuclear Information System (INIS)

    Dose distribution within a human body can be measured using physical anthropomorphic phantoms. In an effort to establish reference Korean physical model, the first Korean physical phantom of average Korean adult male was constructed using computed tomography (CT) images of a healthy volunteer. The body dimension of the subject was close to that of average Korean male. The source images were obtained using fusion positron emission tomography machine at Radiation Health Research Inst. in Korea, and ported into rapid proto-typing process. The physical phantom was composed of three tissue-equivalent materials: epoxy resin, urethane foam and polyurethane representing bone, lungs and soft tissues, respectively. The densities of the tissue-equivalent materials were close to those recommended by the International Commission on Radiation Units and measurements. To facilitate dose mapping, the phantom was sliced into 2 cm sections. Hole grids for thermoluminescence (TL) dosemeter chips were drilled. To verify the appropriateness of the physical phantom, organ doses of selected organs were measured for reference photon beam, and compared with those computed by tomographic model constructed from the same CT images. Absorbed doses converted from TL relative response showed good agreement within 7% with those calculated. (authors)

  15. 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.

  16. 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.

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

    International Nuclear Information System (INIS)

    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

  18. Kids See Human Too: Adapting an Individual Differences Measure of Anthropomorphism for a Child Sample

    Science.gov (United States)

    Severson, Rachel L.; Lemm, Kristi M.

    2016-01-01

    The study of anthropomorphism in adults has received considerable interest with the development of the Individual Differences in Anthropomorphism Questionnaire (IDAQ; Waytz, Cacioppo, & Epley, 2010). Anthropomorphism in children--its development, correlates, and consequences--is also of significant interest, yet a comparable measure does not…

  19. Evaluation of human thorax FE model in various impact scenarios

    Directory of Open Access Journals (Sweden)

    Jansová M.

    2015-06-01

    Full Text Available The study focused on the validation of the 50th percentile male model — a detailed FE model of the thoracic segment of the human body developed within project Development of a Finite Element Model of the Human Thorax and Upper Extremities (THOMO co-funded by the European Commission (7th Framework Programme. The model response was tested in three impact scenarios: frontal, lateral and oblique. The resulting impactor contact force vs. time and chest deflection vs. time responses were compared with experimental results. The strain profile of the 5th rib was checked with lateral and oblique strain profiles from post-mortem human subject (PMHS experiments. The influence of heart and lungs on the mechanical response of the model was assessed and the material data configuration, giving the most biofidelic thorax behaviour, was identified.

  20. Radiography of the equine thorax and its differential diagnosis relevance

    International Nuclear Information System (INIS)

    Commonly chronic obstructive pulmonary disease (COPD) is the cause of dyspnoe or loss of performance in the horse. Tracheobronchoscopy, cytology of tracheobronchial aspirates, interpleural pressure measurement, and arterial blood gas analysis improved diagnosis of equine respiratory disorders. Yet some intrathoraeie diseases, especially chronic pneumonia, are differential diagnosis problems. Radiography of the thorax improves the diagnosis of pneumonia and some other intrathoraeie diseases. The technique of the radiography of the thorax is described and radiographic findings in 166 horses suffering from respiratory diseases are evaluated. Theses horses showed pathologic radiographic findings caused by COPD (n =61), pneumonia (67), pleuritis (12), exercise-induced pulmonary haemorrhage (8), aspiration pneumonia (7), hydrothorax (6), pneumothorax (2), lung abseess (1); mediastinal tumor (1), and diaphragmatie hernia (1)

  1. Radio-protective aprons during radiological examinations of the thorax: An optimum strategy

    International Nuclear Information System (INIS)

    The current work investigates the most effective type/position of aprons for postero-anterior (PA) and lateral projections of the chest. Two apron-types were investigated: 'Mavig' half apron and Amray light plus' wrap-around apron. The half apron was positioned at the X-ray tube or image receptor side of an anthropomorphic phantom for PA and lateral projections. Radiation dose at positions corresponding to ovaries, uterus and testes was measured with thermoluminescent dosemeters. The wrap-around apron offers a higher level of protection for PA and lateral projections compared with the half apron, regardless of where the latter was positioned, with dose reductions of up to 88% compared with no apron. For the PA position, the half apron should be positioned in a gender-specific way, facing the X-ray tube for females and the image receptor for males. With all apron types/positions, gonadal dose is still clearly evident, from internal scatter, emphasising the importance of other protective practices such as collimation. (authors)

  2. Calibration of a large hyperpure germanium array for in-vivo detection of the actinides with a tissue-equivalent torso phantom

    International Nuclear Information System (INIS)

    For calibration of the array for internally deposited 238Pu, 239Pu, and 241Am, a tissue-equivalent anthropomorphic phantom, was used for efficiency determinations at the ORNL facility. This phantom consists of a tissue-equivalent torso into which is imbedded an adult male skeleton, interchangeable organs containing a homogeneous distribution of various radionuclides, and two sets of chest overlay plates for simulation of progressively thicker tissue over the chest, as well as differing thoracic fat contents

  3. Application of a sitting MIRD phantom for effective dose calculations

    International Nuclear Information System (INIS)

    In typical realistic scenarios, dose factors due to 60Co contaminated steel, used in consumer products, cannot be approximated by standard exposure geometries. It is then necessary to calculate the effective dose using an appropriate anthropomorphic phantom. MCNP calculations were performed using a MIRD human model in two settings. In the first, a male office worker is sitting in a chair containing contaminated steel, surrounded by contaminated furniture. In the second, a male driver is seated inside an automobile, the steel of which is uniformly contaminated. To accurately calculate the dose to lower body organs, especially the gonads, it was essential to modify the MIRD model to simulate two sitting postures: chair and driving position. The phantom modifications are described, and the results of the calculations are presented. In the case of the automobile scenarios, results are compared to those obtained using an isotropic fluence-to-dose conversion function. (authors)

  4. Study of dose distributions in voxel phantoms for brachytherapy sources using the GEANT4 Monte Carlo toolkit

    International Nuclear Information System (INIS)

    This work studies the effects of corrections in the calculation of dose distribution for brachytherapy sources when they are inserted in a male human voxel phantom. The sources studied here are the Best Industries 125I 2301 model for low dose rate and the Amersham Buchler G0814 model 192Ir seed for high dose rate, in the simulation of prostate treatments. The presence of organs around the interest point scatters radiation in a different form than a water cube, the situation that is usually configured in these calculations. The insertion of the sources in an anthropomorphic phantom brings results closer to the real situation. The chosen phantom was the head and torso voxel phantom created by Zubal. The Geant4 Monte Carlo toolkit was used to simulate the radiation transportation along the source shielding and the human organs of the voxel phantom. After inserting the source in the phantom, the energy deposition in each voxel is computed, allowing the construction of isodose curves. The source insertion in the anthropomorphic phantom aims also at a further knowledge about the brachytherapy treatment planning and additional information such as the target volume dose and in neighbor organs, data that will be useful for medical staff working with this technique. (author)

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2014-11-01

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

  7. Perturbation correction for alanine dosimeters in different phantom materials in high-energy photon beams

    Science.gov (United States)

    von Voigts-Rhetz, P.; Anton, M.; Vorwerk, H.; Zink, K.

    2016-02-01

    In modern radiotherapy the verification of complex treatments plans is often performed in inhomogeneous or even anthropomorphic phantoms. For dose verification small detectors are necessary and therefore alanine detectors are most suitable. Though the response of alanine for a wide range of clinical photon energies in water is well know, the knowledge about the influence of the surrounding phantom material on the response of alanine is sparse. Therefore we investigated the influence of twenty different surrounding/phantom materials for alanine dosimeters in clinical photon fields via Monte Carlo simulations. The relative electron density of the used materials was in the range {{n}e}/{{n}e,\\text{w}}=0.20 up to 1.69, covering almost all materials appearing in inhomogeneous or anthropomorphic phantoms used in radiotherapy. The investigations were performed for three different clinical photon spectra ranging from 6 to 25 MV-X and Co-60 and as a result a perturbation correction {{k}\\text{env}} depending on the environmental material was established. The Monte Carlo simulation show, that there is only a small dependence of {{k}\\text{env}} on the phantom material and the photon energy, which is below  ±0.6%. The results confirm the good suitability of alanine detectors for in-vivo dosimetry.

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

    International Nuclear Information System (INIS)

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

  9. Geometric Phantom Categories

    OpenAIRE

    Gorchinskiy, Sergey; Orlov, Dmitri

    2012-01-01

    In this paper we give a construction of phantom categories, i.e. admissible triangulated subcategories in bounded derived categories of coherent sheaves on smooth projective varieties that have trivial Hochschild homology and trivial Grothendieck group. We also prove that these phantom categories are phantoms in a stronger sense, namely, they have trivial K-motives and, hence, all their higher K-groups are trivial too.

  10. Interacting Holographic Phantom

    OpenAIRE

    Setare, M. R.

    2007-01-01

    In this paper we consider the holographic model of interacting dark energy in non-flat universe. With the choice of $c\\leq 0.84$, the interacting holographic dark energy can be described by a phantom scalar field. Then we show this phantomic description of the holographic dark energy with $c\\leq 0.84$ and reconstruct the potential of the phantom scalar field.

  11. Design and fabrication of a multipurpose thyroid phantom for medical dosimetry and calibration

    International Nuclear Information System (INIS)

    A multipurpose anthropomorphic neck phantom was designed and fabricated for use in medical applications. The designed neck phantom is composed of seven elliptic cylindrical slices with a semi-major axis of 14 cm and a semi-minor axis of 12.5 cm, each having the thickness of 2 cm. The thyroid gland, bony part of the neck, and the windpipe were also built inside the neck phantom. For the purpose of medical dosimetry, some holes were drilled inside the phantom to accommodate the thermoluminescence dosemeters with different shapes and dimensions. For testing the quality of images in nuclear medicine, the thyroid gland was built separately to accommodate the radioactive iodine. Finally, the nuclear medicine images were obtained by inserting 131I in both male and female thyroid parts. (authors)

  12. Phantom Crossing DGP Gravity

    OpenAIRE

    Hirano, Koichi; Komiya, Zen

    2010-01-01

    We propose a phantom crossing Dvali--Gabadadze--Porrati (DGP) model. In our model, the effective equation of state of the DGP gravity crosses the phantom divide line. We demonstrate crossing of the phantom divide does not occur within the framework of the original DGP model or the DGP model developed by Dvali and Turner. By extending their model, we construct a model that realizes crossing of the phantom divide. DGP models can account for late-time acceleration of the universe without dark en...

  13. Automated phantom assay system

    International Nuclear Information System (INIS)

    This paper describes an automated phantom assay system developed for assaying phantoms spiked with minute quantities of radionuclides. The system includes a computer-controlled linear-translation table that positions the phantom at exact distances from a spectrometer. A multichannel analyzer (MCA) interfaces with a computer to collect gamma spectral data. Signals transmitted between the controller and MCA synchronize data collection and phantom positioning. Measured data are then stored on disk for subsequent analysis. The automated system allows continuous unattended operation and ensures reproducible results

  14. SU-F-BRE-08: Feasibility of 3D Printed Patient Specific Phantoms for IMRT/IGRT QA

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-06-15

    Purpose: Test the feasibility of 3D printed, per-patient phantoms for IMRT QA to analyze the treatment delivery quality within the patient geometry. Methods: Using the head and neck region of an anthropomorphic phantom as a substitute for an actual patient, a soft-tissue equivalent model was constructed with the use of a 3D printer. A nine-field IMRT plan was constructed and dose verification measurements were performed for the 3D printed phantom. During the delivery of the IMRT QA on to the 3D printed phantom, the same patient positioning indexing system was used on the phantom and image guidance (cone beam CT) was used to localize the phantom, serving as a test of the IGRT system as well. The 3D printed phantom was designed to accommodate four radiochromic film planes (two axial, one coronal and one sagittal) and an ionization chamber measurement. As a frame of comparison, the IMRT QA was also performed on traditional phantoms. Dosimetric tolerance levels such as 3mm / 3% Gamma Index as well as 3% and 5% dose difference were considered. All detector systems were calibrated against a NIST traceable ionization chamber. Results: Comparison of results 3D printed patient phantom with the standard IMRT QA systems showed similar passing rates for the 3D printed phantom and the standard phantoms. However, the locations of the failing regions did not necessarily correlate. The 3D printed phantom was localized within 1 mm and 1° using on-board cone beam CT. Conclusion: A custom phantom was created using a 3D printer. It was determined that the use of patient specific phantoms to perform dosimetric verification and estimate the dose in the patient is feasible. In addition, end-to-end testing on a per-patient basis was possible with the 3D printed phantom. Further refinement of the phantom construction process is needed for routine clinical use.

  15. SU-F-BRE-08: Feasibility of 3D Printed Patient Specific Phantoms for IMRT/IGRT QA

    International Nuclear Information System (INIS)

    Purpose: Test the feasibility of 3D printed, per-patient phantoms for IMRT QA to analyze the treatment delivery quality within the patient geometry. Methods: Using the head and neck region of an anthropomorphic phantom as a substitute for an actual patient, a soft-tissue equivalent model was constructed with the use of a 3D printer. A nine-field IMRT plan was constructed and dose verification measurements were performed for the 3D printed phantom. During the delivery of the IMRT QA on to the 3D printed phantom, the same patient positioning indexing system was used on the phantom and image guidance (cone beam CT) was used to localize the phantom, serving as a test of the IGRT system as well. The 3D printed phantom was designed to accommodate four radiochromic film planes (two axial, one coronal and one sagittal) and an ionization chamber measurement. As a frame of comparison, the IMRT QA was also performed on traditional phantoms. Dosimetric tolerance levels such as 3mm / 3% Gamma Index as well as 3% and 5% dose difference were considered. All detector systems were calibrated against a NIST traceable ionization chamber. Results: Comparison of results 3D printed patient phantom with the standard IMRT QA systems showed similar passing rates for the 3D printed phantom and the standard phantoms. However, the locations of the failing regions did not necessarily correlate. The 3D printed phantom was localized within 1 mm and 1° using on-board cone beam CT. Conclusion: A custom phantom was created using a 3D printer. It was determined that the use of patient specific phantoms to perform dosimetric verification and estimate the dose in the patient is feasible. In addition, end-to-end testing on a per-patient basis was possible with the 3D printed phantom. Further refinement of the phantom construction process is needed for routine clinical use

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

    Science.gov (United States)

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

    2010-01-01

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

  17. Monte Carlo model of the female RANDO phantom irradiation with an Elekta Precise linear accelerator

    International Nuclear Information System (INIS)

    Anthropomorphic laboratory phantoms are a very useful aid in radiotherapy treatment planning. Such phantoms allow estimating detailed mapping of dose distribution. The phantom utilized in this work is the female RANDO Phantom, which represents a 163 cm tall and 54 kg figure that does not have arms or legs. It is constructed with a natural human skeleton which is cast inside soft tissue-simulating material and lung-simulating material. A set of computer tomography images of the RANDO Phantom was obtained and segmented. Once the slices were segmented and the pixel intensities related with the phantom materials, they were input to a Matlab algorithm developed by the authors and validated in previous works, which uses the CT slices to build up a three-dimensional numerical voxelized phantom by pixel and material identification, and writes it in the MCNP5 input deck format utilizing the lattice card, together with an MCNP5 model for the Elekta Precise Linear Accelerator. The Linear Accelerator model has also been also validated in previous works. The simulation results in mapping of dose distribution inside the phantom, utilizing the MCNP5 tool FMESH, superimposed mesh tally, which allows registering the results over the problem geometry.

  18. Development of age-specific Japanese head phantoms for dose evaluation in paediatric head CT examinations

    International Nuclear Information System (INIS)

    In this study, the authors developed age-specific physical head phantoms simulating the physique of Japanese children for dose evaluation in paediatric head computed tomography (CT) examinations. Anatomical structures at 99 places in 0-, 0.5-, 1- and 3-y-old Japanese patients were measured using DICOM viewer software from CT images, and the head phantom of each age was designed. For trial manufacture, a 3-y-old head phantom consisting of acrylic resin and gypsum was produced by machine processing. Radiation doses for the head phantom were measured with radiophotoluminescence glass dosemeters and Si-pin photodiode dosemeters. To investigate whether the phantom shape was suitable for dose evaluation, organ doses in the same scan protocol were compared between the 3-y-old head and commercially available anthropomorphic phantoms having approximately the same head size. The doses of organs in both phantoms were equivalent. The authors' designed paediatric head phantom will be useful for dose evaluation in paediatric head CT examinations. (authors)

  19. Phantom Torso model

    Science.gov (United States)

    2003-01-01

    The Phantom Torso is a tissue-muscle plastic anatomical model of a torso and head. It contains over 350 radiation measuring devices to calculate the radiation that penetrates internal organs in space travel. The Phantom Torso is one of three radiation experiments in Expedition Two including the Borner Ball Neutron Detector and Dosimetric Mapping.

  20. Dynamic phantom for computertomography

    Energy Technology Data Exchange (ETDEWEB)

    Nuesslin, 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 quality assuarance measurements in computertomography. 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 annother 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 Computertomograph.

  1. Evolution of prehension ability in an anthropomorphic neurorobotic arm

    Directory of Open Access Journals (Sweden)

    Gianluca Massera

    2007-11-01

    Full Text Available In this paper, we show how a simulated anthropomorphic robotic arm controlled by an artificial neural network can develop effective reaching and grasping behaviour through a trial and error process in which the free parameters encode the control rules which regulate the fine-grained interaction between the robot and the environment and variations of the free parameters are retained or discarded on the basis of their effects at the level of the global behaviour exhibited by the robot situated in the environment. The obtained results demonstrate how the proposed methodology allows the robot to produce effective behaviours thanks to its ability to exploit the morphological properties of the robot's body (i.e. its anthropomorphic shape, the elastic properties of its muscle-like actuators and the compliance of its actuated joints and the properties which arise from the physical interaction between the robot and the environment mediated by appropriate control rules.

  2. Diagnosis of anemia on CT scans of the thorax

    International Nuclear Information System (INIS)

    Visualization of the interventricular septum on nonenhanced CT scans of the thorax of patients with anemia has been illustrated in the literature and explained in terms of a density differential between the cardiac musculature and the blood of anemic patients (blood with a low hemoglobin level). There are no data on the frequency of visualization of the walls of the cardiac chambers, the aorta and its branches, the superior and inferior venae cavae, the brachiocephalic veins, the azygos arch, and so forth. Experience with 50 patients is reported in terms of the foregoing. Findings are correlated with the severity of the anemia, thereby indicating how commonly one may encounter such an appearance

  3. Computed tomography of the thorax in children with cystic fibrosis

    International Nuclear Information System (INIS)

    We studied retrospectively the value of computed tomography of the thorax in patients suffering from cystic fibrosis. Twenty-six patients were studied, which showed as the most frequency pulmonary findings bronchial wall thickening in 22 patients (84.6), followed by bronchiectasis in 16 patients (61.5%). Less frequent finding were ill-defined patch consolidation, mucoid impaction, bullaes and atelectasis. We found a predominant distribution of bronchial wall thickening and bronchiectasis in the upper lobes of the lungs. Computed tomography is the more sensitive technique for early visualization and location of the manifestations of cystic fibrosis bronchopathy. (author)

  4. Phantom dosimetry at 15 MV conformal radiation therapy

    International Nuclear Information System (INIS)

    The main goal of this work was to evaluate the spatial dose distribution into a tumor simulator inside a head phantom exposed to a 15MV 3D conformal radiation therapy in order to validate internal doses. A head and neck phantom developed by the Ionizing Radiation Research Group (NRI) was used on the experiments. Therapy Radiation planning (TPS) was performed based on those CT images, satisfying a 200 cGy prescribed dose split in three irradiation fields. The TPS assumed 97% of prescribed dose cover the prescribed treatment volume (PTV). Radiochromic films in a solid water phantom provided dose response as a function of optical density. Spatial dosimetric distribution was generated by radiochromic film samples inserted into tumor simulator and brain. The spatial dose profiles held 70 to 120% of the prescribed dose. In spite of the stratified profile, as opposed to the smooth dose profile from TPS, the tumor internal doses were within a 5% deviation from 214.4 cGy evaluated by TPS. 83.2% of the points with a gamma value of less than 1 (3%/3mm) for TPS and experimental values, respectively. At the tumor, a few dark spots in the film caused the appearance of outlier points in 13-15% of dose deviation percentage. As final conclusion, such dosimeter choice and the physical anthropomorphic and anthropometric phantom provided an efficient method for validating radiotherapy protocols. (author)

  5. Phantom dosimetry at 15 MV conformal radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Larissa; Campos, Tarcisio P.R., E-mail: larissathompson@hotmail.com, E-mail: tprcampos@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Minas Gerais, MG (Brazil). Dept. de Engenharia Nuclear; Dias, Humberto G., E-mail: fisicamedica.hl@mariopenna.org.br [Instituto Mario Penna, Minas Gerais, MG (Brazil). Hospital Luxemburgo

    2013-07-01

    The main goal of this work was to evaluate the spatial dose distribution into a tumor simulator inside a head phantom exposed to a 15MV 3D conformal radiation therapy in order to validate internal doses. A head and neck phantom developed by the Ionizing Radiation Research Group (NRI) was used on the experiments. Therapy Radiation planning (TPS) was performed based on those CT images, satisfying a 200 cGy prescribed dose split in three irradiation fields. The TPS assumed 97% of prescribed dose cover the prescribed treatment volume (PTV). Radiochromic films in a solid water phantom provided dose response as a function of optical density. Spatial dosimetric distribution was generated by radiochromic film samples inserted into tumor simulator and brain. The spatial dose profiles held 70 to 120% of the prescribed dose. In spite of the stratified profile, as opposed to the smooth dose profile from TPS, the tumor internal doses were within a 5% deviation from 214.4 cGy evaluated by TPS. 83.2% of the points with a gamma value of less than 1 (3%/3mm) for TPS and experimental values, respectively. At the tumor, a few dark spots in the film caused the appearance of outlier points in 13-15% of dose deviation percentage. As final conclusion, such dosimeter choice and the physical anthropomorphic and anthropometric phantom provided an efficient method for validating radiotherapy protocols. (author)

  6. Phantom dosimetry at 15 MV conformal radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Larissa; Campos, Tarcisio P.R., E-mail: larissathompson@hotmail.com, E-mail: tprcampos@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Dias, Humberto G., E-mail: fisicamedica.hl@mariopenna.org.br [Luxemburgo Hospital, Mario Penna Institute, Belo Horizonte, MG (Brazil)

    2015-07-01

    The main goal of this work was to evaluate the spatial dose distribution into a tumor simulator inside a head phantom exposed to a 15MV 3D conformal radiation therapy in order to validate internal doses. A head and neck phantom developed by the Ionizing Radiation Research Group (NRI) was used on the experiments. Therapy Radiation planning (TPS) was performed based on those CT images, satisfying a 200 cGy prescribed dose split in three irradiation fields. The TPS assumed 97% of prescribed dose cover the prescribed treatment volume (PTV). Radiochromic films in a solid water phantom provided dose response as a function of optical density. Spatial dosimetric distribution was generated by radiochromic film samples inserted into tumor simulator and brain. The spatial dose profiles held 70 to 120% of the prescribed dose. In spite of the stratified profile, as opposed to the smooth dose profile from TPS, the tumor internal doses were within a 5% deviation from 214.4 cGy evaluated by TPS. 83.2% of the points with a gamma value of less than 1 (3%/3mm) for TPS and experimental values, respectively. At the tumor, a few dark spots in the film caused the appearance of outlier points in 13-15% of dose deviation percentage. As final conclusion, such dosimeter choice and the physical anthropomorphic and anthropometric phantom provided an efficient method for validating radiotherapy protocols. (author)

  7. Leap Motion Device Used to Control a Real Anthropomorphic Gripper

    OpenAIRE

    Staretu, Ionel; Moldovan, Catalin

    2016-01-01

    This paper presents for the first time the use of the Leap Motion device to control an anthropomorphic gripper with five fingers. First, a description of the Leap Motion device is presented, highlighting its main functional characteristics, followed by testing of its use for capturing the movements of a human hand’s fingers in different configurations. Next, the HandCommander soft module and the Interface Controller application are described. The HandCommander is a software module created to ...

  8. Anthropomorphic Soft Robotics - from Torque Control to Variable Intrinsic Compliance

    OpenAIRE

    Albu-Schäffer, Alin; Eiberger, Oliver; Fuchs, Matthias; Grebenstein, Markus; Haddadin, Sami; Ott, Christian; Stemmer, Andreas; Wimböck, Thomas; Wolf, Sebastian; Borst, Christoph; Hirzinger, Gerd

    2011-01-01

    The paper gives an overview on the developments at the German Aerospace enter DLR towards anthropomorphic robots which not only try to approach the force and velocity performance of humans, but also have similar safety and robustness features based on a compliant behaviour. We achieve this compliance either by joint torque sensing and impedance control, or, in our newest systems, by compliant mechanisms (so called VIA - variable impedance actuators), whose intrinsic compliance can be adjusted...

  9. Management system compliance regime equilibrium anthropomorphic walking machine

    OpenAIRE

    Ткач, Михайло Мартинович

    2014-01-01

    The paper provides a solution to the problem of the control system compliance regime equilibrium anthropomorphic walking machine on any solid surface by applying the principle of tracking the movement of the point of the center of mass system and the reaction force supporting surface. Used the concept of a distributed control system with the optimal criterion of balancing and adjusting the current position AKA by solving the inverse kinematics problem using adaptive neuro-fuzzy network foreca...

  10. The LLNL voxel phantom: comparison with the physical phantom and previous virtual phantoms.

    Science.gov (United States)

    Kramer, Gary H; Capello, Kevin; Sung, Jeremy

    2007-12-01

    The Human Monitoring Laboratory has created a voxel phantom from computer tomography scans of the Lawrence Livermore National Laboratory (LLNL) torso phantom for use in Monte Carlo simulations. The voxel phantom has been compared to the previously developed mathematical phantom using Monte Carlo simulations and both virtual phantoms have been compared to physical measurement of the LLNL phantom. The voxel phantom agreed well with the others, except at very low photon energies (i.e., 17.5 keV), with predicted counting efficiencies being within 2% of the counting efficiencies from the other two phantoms at 59.5 keV and above. The mathematical phantom performs similarly to the voxel phantom, but much faster, so it is an excellent alternative if computer power is lacking. The voxel phantom of the LLNL phantom is available from the authors, on request. PMID:17993850

  11. A fully automatic, threshold-based segmentation method for the estimation of the Metabolic Tumor Volume from PET images: validation on 3D printed anthropomorphic oncological lesions

    Science.gov (United States)

    Gallivanone, F.; Interlenghi, M.; Canervari, C.; Castiglioni, I.

    2016-01-01

    18F-Fluorodeoxyglucose (18F-FDG) Positron Emission Tomography (PET) is a standard functional diagnostic technique to in vivo image cancer. Different quantitative paramters can be extracted from PET images and used as in vivo cancer biomarkers. Between PET biomarkers Metabolic Tumor Volume (MTV) has gained an important role in particular considering the development of patient-personalized radiotherapy treatment for non-homogeneous dose delivery. Different imaging processing methods have been developed to define MTV. The different proposed PET segmentation strategies were validated in ideal condition (e.g. in spherical objects with uniform radioactivity concentration), while the majority of cancer lesions doesn't fulfill these requirements. In this context, this work has a twofold objective: 1) to implement and optimize a fully automatic, threshold-based segmentation method for the estimation of MTV, feasible in clinical practice 2) to develop a strategy to obtain anthropomorphic phantoms, including non-spherical and non-uniform objects, miming realistic oncological patient conditions. The developed PET segmentation algorithm combines an automatic threshold-based algorithm for the definition of MTV and a k-means clustering algorithm for the estimation of the background. The method is based on parameters always available in clinical studies and was calibrated using NEMA IQ Phantom. Validation of the method was performed both in ideal (e.g. in spherical objects with uniform radioactivity concentration) and non-ideal (e.g. in non-spherical objects with a non-uniform radioactivity concentration) conditions. The strategy to obtain a phantom with synthetic realistic lesions (e.g. with irregular shape and a non-homogeneous uptake) consisted into the combined use of standard anthropomorphic phantoms commercially and irregular molds generated using 3D printer technology and filled with a radioactive chromatic alginate. The proposed segmentation algorithm was feasible in a

  12. [Phantom limb pains].

    Science.gov (United States)

    Giraux, Pascal

    2015-03-01

    With the radical experience of an amputation, the adaptation of body image is often incomplete. Some people experience phantom body perceptions, often painful and difficult to treat, after the amputation of a limb. PMID:26145132

  13. Lung pair phantom

    Science.gov (United States)

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

    1993-01-01

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

  14. Lung pair phantom

    International Nuclear Information System (INIS)

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

  15. Axion phantom energy

    OpenAIRE

    González-Díaz, Pedro F.

    2004-01-01

    The existence of phantom energy in a universe which evolves to eventually show a big rip doomsday is a possibility which is not excluded by present observational constraints. In this paper it is argued that the field theory associated with a simple quintessence model is compatible with a field definition that is interpretable in terms of a rank-3 axionic tensor field, whenever we consider a perfect-fluid equation of state that corresponds to the phantom energy regime. Explicit expressions for...

  16. Stability of phantom wormholes

    International Nuclear Information System (INIS)

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

  17. Roomba is not a Robot; AIBO is still Alive! Anthropomorphic Language in Online Forums

    OpenAIRE

    Fink, Julia; Mubin, Omar; Kaplan, Frédéric; Dillenbourg, Pierre

    2011-01-01

    Anthropomorphism describes people’s tendency to ascribe humanlike qualities to non-human artifacts, such as robots. We investigated anthropomorphic language in 750 posts of online forums about the Roomba robotic vacuum cleaner, the AIBO robotic dog and the iPad tablet computer. Results of this content analysis suggest a significant difference for anthropomorphic language usage among the three technologies. In contrast to Roomba and iPad, the specific characteristics of the robotic dog enhance...

  18. The human-animal bond: role of anthropomorphism in diversity and variation

    OpenAIRE

    Adams, Judith C.; McBride, E. Anne; Carr, A; Carnelly, K.

    2010-01-01

    Adams et.al (2007) suggested a predictive model based on the dimensions of empathy, attachment and sexual attraction to differentiate between zoophilia and bestiality (animal sexual abuse). This paper develops this model by considering the role of anthropomorphism. It is known that anthropomorphism changes ‘normal’ care giving practices of pet owners (White, 2007). We suggest that anthropomorphism may have a significant effect on the human – animal bond by blurring the lines between sensual ...

  19. Anthropomorphism of belief: An attempt based on the works of Feuerbach, Freud and Guthrie

    OpenAIRE

    Kjartan Þór Ingvarsson 1981

    2009-01-01

    The aim of this thesis is to explore the anthropomorphism of belief. The main questions are: Is a theory explicating religion on the grounds of anthropomorphism possible? How could one explain the need for belief and where it comes from? How does religion mirror fundamental aspects of being within the world? Theories explaining religion as anthropomorphism have been proposed, most noticeably and comprehensively, by Ludwig Feuerbach in his books, The Essence of Religion and The Essence of Chri...

  20. A phantom for measuring the isodose distribution in intracavitary radiotherapy of cervical carcinoma

    International Nuclear Information System (INIS)

    A nonuniform tissue equivalent anthropomorphic phantom of female hip, which was intended for measuring the isodose distributions in intracavitary radio therapy of cervical carcinoma, was developed. It was made of bone and muscle equivalent materials. CT number of normal organs and tissues in pelvis cavity and lower abdomen of the female were measured with CT scanner and compared with those values obtained from home-made phantom under same scan conditions. The electron density effective atomic number, mass density and CT number of equivalent muscle were as essentially same as real muscle. The clinical application of this phantom showed that its construction is reasonable, convenient in use and suitable for measuring isodose distributions for different programs of intracavitary radio therapy of cervical carcinoma

  1. Evaluation of organ doses in brachytherapy treatment of uterus cancer using mathematical reference Indian adult phantom

    International Nuclear Information System (INIS)

    Quantifying organ dose to healthy organs during radiotherapy is essential to estimate the radiation risk. Dose factors are generated by simulating radiation transport through an anthropomorphic mathematical phantom representing a reference Indian adult using the Monte Carlo method. The mean organ dose factors (in mGy min-1 GBq-1) are obtained considering the Micro Selectron 192Ir source and BEBIG 60Co sources in the uterus of a reference Indian adult female phantom. The present study provides the factors for mean absorbed dose to organs applicable to the Indian female patient population undergoing brachytherapy treatment of uterus cancer. This study also includes a comparison of the dimension of organs in the phantom model with measured values of organs in the various investigated patients. (author)

  2. Phantom energy traversable wormholes

    International Nuclear Information System (INIS)

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

  3. Radiological profile of anemia on unenhanced MDCT of the thorax

    International Nuclear Information System (INIS)

    Our aim was to investigate the diagnostic value of unenhanced MDCT in anemic patients. Fifty consecutive patients with proven anemia and 50 nonanemic matched group for age, sex and body mass index were evaluated. In either group, hemoglobin levels were assessed no more than 24 h from an unenhanced CT of the thorax. For each patient, the presence of a hyperattenuating aortic wall (aortic ring sign) and/or dense interventricular septum (subjective parameters) were identified by two radiologists who were blinded to the laboratory findings. Furthermore, the aortic CT attenuation values (objective parameter) were also obtained and correlated with the hemoglobin levels. The sensitivity and specificity in detecting anemia were calculated for each variable, and ROC analysis was generated for subjective and objective parameters. Subjective image analysis revealed that the aortic ring sign was more sensitive than the interventricular septum sign for anemia detection (84% vs. 72%), whereas this latter sign was more specific (100% vs. 92%). A good correlation (r=0.60) was observed between the aortic CT attenuation values and the hemoglobin levels in the whole study population. Using a threshold of ≤35 HU for anemia diagnosis, the sensitivity and specificity of aortic CT attenuation value were 84% and 94%, respectively, with the largest area under the curve (0.89) among all diagnostic criteria. However, the best trade-off between sensitivity (80%) and specificity (100%) was obtained from combining both subjective and objective analysis. Interpreting anemia upon unnenhanced MDCT of the thorax is quite feasible. A diagnostic approach that considers both subjective and objective analysis offers the best trade-off between sensitivity and specificity. (orig.)

  4. Computational high-resolution heart phantoms for medical imaging and dosimetry simulations

    International Nuclear Information System (INIS)

    Cardiovascular disease in general and coronary artery disease (CAD) in particular, are the leading cause of death worldwide. They are principally diagnosed using either invasive percutaneous transluminal coronary angiograms or non-invasive computed tomography angiograms (CTA). Minimally invasive therapies for CAD such as angioplasty and stenting are rendered under fluoroscopic guidance. Both invasive and non-invasive imaging modalities employ ionizing radiation and there is concern for deterministic and stochastic effects of radiation. Accurate simulation to optimize image quality with minimal radiation dose requires detailed, gender-specific anthropomorphic phantoms with anatomically correct heart and associated vasculature. Such phantoms are currently unavailable. This paper describes an open source heart phantom development platform based on a graphical user interface. Using this platform, we have developed seven high-resolution cardiac/coronary artery phantoms for imaging and dosimetry from seven high-quality CTA datasets. To extract a phantom from a coronary CTA, the relationship between the intensity distribution of the myocardium, the ventricles and the coronary arteries is identified via histogram analysis of the CTA images. By further refining the segmentation using anatomy-specific criteria such as vesselness, connectivity criteria required by the coronary tree and image operations such as active contours, we are able to capture excellent detail within our phantoms. For example, in one of the female heart phantoms, as many as 100 coronary artery branches could be identified. Triangular meshes are fitted to segmented high-resolution CTA data. We have also developed a visualization tool for adding stenotic lesions to the coronaries. The male and female heart phantoms generated so far have been cross-registered and entered in the mesh-based Virtual Family of phantoms with matched age/gender information. Any phantom in this family, along with user

  5. DEEP code to calculate dose equivalents in human phantom for external photon exposure by Monte Carlo method

    International Nuclear Information System (INIS)

    The present report describes a computer code DEEP which calculates the organ dose equivalents and the effective dose equivalent for external photon exposure by the Monte Carlo method. MORSE-CG, Monte Carlo radiation transport code, is incorporated into the DEEP code to simulate photon transport phenomena in and around a human body. The code treats an anthropomorphic phantom represented by mathematical formulae and user has a choice for the phantom sex: male, female and unisex. The phantom can wear personal dosimeters on it and user can specify their location and dimension. This document includes instruction and sample problem for the code as well as the general description of dose calculation, human phantom and computer code. (author)

  6. 21. Phantom pain.

    Science.gov (United States)

    Wolff, Andre; Vanduynhoven, Eric; van Kleef, Maarten; Huygen, Frank; Pope, Jason E; Mekhail, Nagy

    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 patients with phantom pain have stump pain as well. Phantom pain can also occur in other parts of the body; it has been described after mastectomies and enucleation of the eye. Most patients with phantom pain have intermittent pain, with intervals that range from 1 day to several weeks. Even intervals of over a year have been reported. The pain often presents itself in the form of attacks that vary in duration from a few seconds to minutes or hours. In most cases, the pain is experienced distally in the missing limb, in places with the most extensive innervation density and cortical representation. Although there are still many questions as to the underlying mechanisms, peripheral as well as central neuronal mechanisms seem to be involved. Conservative therapy consists of drug treatment with amitriptyline, tramadol, carbamazepine, ketamine, or morphine. Based on the available evidence some effect may be expected from drug treatment. When conservative treatment fails, pulsed radiofrequency treatment of the stump neuroma or of the spinal ganglion (DRG) or spinal cord stimulation could be considered (evidence score 0). These treatments should only be applied in a study design. PMID:21447079

  7. Dose verification of radiotherapy for lung cancer by using plastic scintillator dosimetry and a heterogeneous phantom

    International Nuclear Information System (INIS)

    Bone, air passages, cavities, and lung are elements present in patients, but challenging to properly correct for in treatment planning dose calculations. Plastic scintillator detectors (PSDs) have proven to be well suited for dosimetry in non-reference conditions such as small fields. The objective of this study was to investigate the performance of a commercial treatment planning system (TPS) using a PSD and a specially designed thorax phantom with lung tumor inserts. 10 treatment plans of different complexity and phantom configurations were evaluated. Although the TPS agreed well with the measurements for the least complex tests, deviations of tumor dose > 4% were observed for some cases. This study underpins the dosimetric challenge in TPS calculations for clinically relevant heterogeneous geometries. The scintillator system, together with the special phantom, provides a promising tool for evaluation of complex radiotherapy dose calculations and delivery

  8. Leap Motion Device Used to Control a Real Anthropomorphic Gripper

    Directory of Open Access Journals (Sweden)

    Ionel Staretu

    2016-06-01

    Full Text Available This paper presents for the first time the use of the Leap Motion device to control an anthropomorphic gripper with five fingers. First, a description of the Leap Motion device is presented, highlighting its main functional characteristics, followed by testing of its use for capturing the movements of a human hand’s fingers in different configurations. Next, the HandCommander soft module and the Interface Controller application are described. The HandCommander is a software module created to facilitate interaction between a human hand and the GraspIT virtual environment, and the Interface Controller application is required to send motion data to the virtual environment and to test the communication protocol. For the test, a prototype of an anthropomorphic gripper with five fingers was made, including a proper hardware system of command and control, which is briefly presented in this paper. Following the creation of the prototype, the command system performance test was conducted under real conditions, evaluating the recognition efficiency of the objects to be gripped and the efficiency of the command and control strategies for the gripping process. The gripping test is exemplified by the gripping of an object, such as a screw spanner. It was found that the command system, both in terms of capturing human hand gestures with the Leap Motion device and effective object gripping, is operational. Suggestive figures are presented as examples.

  9. Anthropomorphic Design of the Human-Like Walking Robot

    Institute of Scientific and Technical Information of China (English)

    Ming-Hsun Chiang; Fan-Ren Chang

    2013-01-01

    In this paper,we present a new concept of the mechanical design of a humanoid robot.The goal is to build a humanoid robot utilizing a new structure which is more suitable for human-like walking with the characteristics of the knee stretch,heel-contact,and toe-off.Inspired by human skeleton,we made an anthropomorphic pelvis for the humanoid robot.In comparison with conventional humanoid robots,with such the anthropomorphic pelvis,our robot is capable of adjusting the center of gravity of the upper body by the motion of pelvic tilt,thus reducing the required torque at the ankle joint and the velocity variations in human-like walking.With more precise analysis of the foot mechanism,the fixed-length inverted pendulum can be used to describe the dynamics of biped walking,thus preventing redundant works and power consumption in length variable inverted pendulum system.As the result of the new structure we propose,a humanoid robot is able to walk with human-like gait.

  10. Anthropomorphic Bias Found in Typically Developing Children Is Not Found in Children with Autistic Spectrum Disorder

    Science.gov (United States)

    Chaminade, Thierry; Rosset, Delphine; Da Fonseca, David; Hodgins, Jessica K.; Deruelle, Christine

    2015-01-01

    The anthropomorphic bias describes the finding that the perceived naturalness of a biological motion decreases as the human-likeness of a computer-animated agent increases. To investigate the anthropomorphic bias in autistic children, human or cartoon characters were presented with biological and artificial motions side by side on a touchscreen.…

  11. Anthropomorphizing Science: How Does It Affect the Development of Evolutionary Concepts?

    Science.gov (United States)

    Legare, Cristine H.; Lane, Jonathan D.; Evans, E. Margaret

    2013-01-01

    Despite the ubiquitous use of anthropomorphic language to describe biological change in both educational settings and popular science, little is known about how anthropomorphic language influences children's understanding of evolutionary concepts. In an experimental study, we assessed whether the language used to convey evolutionary concepts…

  12. Lifting the Taboo Regarding Teleology and Anthropomorphism in Biology Education--Heretical Suggestions.

    Science.gov (United States)

    Zohar, Anat; Ginossar, Shlomit

    1998-01-01

    Advocates removing the taboo regarding anthropomorphism and teleology in biology education. Argues that for high school students, accepting such formulations does not necessarily imply anthropomorphic or teleological reasoning. Further, living organisms seem goal-oriented because of their adaptation for survival. Concludes with the argument that…

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

    International Nuclear Information System (INIS)

    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

  14. The Phantom brane revisited

    Science.gov (United States)

    Sahni, Varun

    2016-07-01

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

  15. Jamitons: Phantom Traffic Jams

    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…

  16. Phantom energy from graded algebras

    OpenAIRE

    Chaves, Max; Singleton, Douglas

    2006-01-01

    We construct a model of phantom energy using the graded Lie algebra SU(2/1). The negative kinetic energy of the phantom field emerges naturally from the graded Lie algebra, resulting in an equation of state with w

  17. Egg White Phantoms for HIFU

    International Nuclear Information System (INIS)

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

  18. Dosimetric impact of interplay effect in lung IMRT and VMAT treatment using in-house dynamic thorax phantom

    Science.gov (United States)

    Julia, S.; Nurlely; Soejoko, D. S.

    2016-03-01

    The objective of this research was to determining of protein from connective tissue (protein) in the inner layer of organic and broiler chicken gizzard. The presence of collagens was observed by submersion with 0.1 M NaOH base pH 8 and without submersion. The physiochemical properties and characteristic of collagen from inner layer chicken gizzard such as FTIR spectra, element content, morphology and SDS-PAGE pattern were evaluated. FTIR spectrum in the sample without submersion shown collagen components had wave number that are in the range of wave number (3289-1078 cm-1) bovine collagen. While, FTIR spectrum in the sample with submersion exhibited removal of molecular functional groups and decreasing intensity of infrared absorption. The element content and morphology of two samples indicated that the elements found in the samples were recognized as the elements generally found in proteins and had little structure at SEM micrograph. SDS-PAGE pattern demonstrated that collagen from inner layer chicken gizzard had >120 kDa on molecular unit weight indicating that type 1 collagen is a major component of inner layer chicken gizzard collagen. This study demonstrated the existence of collagen from exploited bio-waste to be an alternative possible source for collagen production.

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

    International Nuclear Information System (INIS)

    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.

  20. Study on a 7-DOF anthropomorphic weld arm

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A kind of new obstacle space expression is proposed in this paper, in which a virtual force field (VFF) is built. Using the torque and joint optimization acted by the virtual force field on the anthropomorphic weld arm, the real-time selection of a redundant join (R-joint) is done and its equivalent virtual torque is obtained, thus the redundant joint can be controlled with whose force feedback. An inverse kinematics solution of a 6-DOF robot is applied to other six joints of the arm. Simulation experiments indicate the new inverse kinematics solution has perfect collision avoidance effect, and it is well simplified. Therefore, it can be applied to a welding task in complex operation space.

  1. The dependence of computed tomography number to relative electron density conversion on phantom geometry and its impact on planned dose.

    Science.gov (United States)

    Inness, Emma K; Moutrie, Vaughan; Charles, Paul H

    2014-06-01

    A computed tomography number to relative electron density (CT-RED) calibration is performed when commissioning a radiotherapy CT scanner by imaging a calibration phantom with inserts of specified RED and recording the CT number displayed. In this work, CT-RED calibrations were generated using several commercially available phantoms to observe the effect of phantom geometry on conversion to electron density and, ultimately, the dose calculation in a treatment planning system. Using an anthropomorphic phantom as a gold standard, the CT number of a material was found to depend strongly on the amount and type of scattering material surrounding the volume of interest, with the largest variation observed for the highest density material tested, cortical bone. Cortical bone gave a maximum CT number difference of 1,110 when a cylindrical insert of diameter 28 mm scanned free in air was compared to that in the form of a 30 × 30 cm(2) slab. The effect of using each CT-RED calibration on planned dose to a patient was quantified using a commercially available treatment planning system. When all calibrations were compared to the anthropomorphic calibration, the largest percentage dose difference was 4.2 % which occurred when the CT-RED calibration curve was acquired with heterogeneity inserts removed from the phantom and scanned free in air. The maximum dose difference observed between two dedicated CT-RED phantoms was ±2.1 %. A phantom that is to be used for CT-RED calibrations must have sufficient water equivalent scattering material surrounding the heterogeneous objects that are to be used for calibration. PMID:24760737

  2. Part of the peritoneal scintigraphy in the hepatic hydro thorax diagnosis: about one case

    International Nuclear Information System (INIS)

    Purpose: The hepatic hydro thorax is a pleural effusion associated with the passage of ascites through diaphragmatic gaps, observed in 5% of cirrhotic patients without cardiac or respiratory abnormalities. We report a liver observation for which the peritoneal scintigraphy helped to highlight the communication and avoid the use of a pleural biopsy. Conclusions: peritoneal scintigraphy is a simple, minimally invasive examination with a sensitivity and specificity very high in the diagnosis of hepatic hydro thorax. (N.C.)

  3. EFEKTIFITAS VARIASI NILAI WINDOW LEVEL TERHADAP KUALITAS HASIL CT SCAN THORAX LUNG WINDOW

    OpenAIRE

    dani, Rahma

    2014-01-01

    EFEKTIFITAS VARIASI NILAI WINDOW LEVEL TERHADAP KUALITAS HASIL CT SCAN THORAX LUNG WINDOW Rahmadani Jurusan Fisika, FMIPA, Universitas Hasanuddin, Makassar 90245, Indonesia Pembimbing Utama : Prof. Dr. H. Halmar Halide, M.Sc Pembimbing Pertama : Dahlang Tahir, M.Sc. Phd ABSTRAK Telah dilakukan penelitian untuk mengetahui efek variasi nilai window level terhadap kualitas hasil CT Scann thorax lung window dengan pengaturan window width 1000,1500, 2000 dengan varias...

  4. Phantom energy traversable wormholes

    CERN Document Server

    Lobo, F S N

    2005-01-01

    It has been suggested that a possible candidate for the present accelerated expansion of the Universe is ''phantom energy''. The latter possesses an equation of state of the form $\\omega\\equiv p/\\rho<-1$, consequently violating the null energy condition. As this is the fundamental ingredient to sustain traversable wormholes, this cosmic fluid presents us with a natural scenario for the existence of these exotic geometries. Due to the fact of the accelerating Universe, macroscopic wormholes could naturally be grown from the submicroscopic constructions that originally pervaded the quantum foam. One could also imagine an advanced civilization mining the cosmic fluid for phantom energy necessary to construct and sustain a traversable wormhole. In this context, we investigate the physical properties and characteristics of traversable wormholes constructed using the equation of state $p=\\omega \\rho$, with $\\omega<-1$. We analyze specific wormhole geometries, considering asymptotically flat spacetimes and imp...

  5. 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.

  6. A realistic 3-D gated cardiac phantom for quality control of gated myocardial perfusion SPET: the Amsterdam gated (AGATE) cardiac phantom

    Energy Technology Data Exchange (ETDEWEB)

    Visser, Jacco J.N.; Busemann Sokole, Ellinor; Verberne, Hein J.; Habraken, Jan B.A.; Eck-Smit, Berthe L.F. van [Department of Nuclear Medicine, Academic Medical Center, Meibergdreef 9, 1105 AZ, Amsterdam (Netherlands); Stadt, Huybert J.F. van de; Jaspers, Joris E.N.; Shehata, Morgan; Heeman, Paul M. [Department of Medical Technological Development, Academic Medical Center, Amsterdam (Netherlands)

    2004-02-01

    A realistic 3-D gated cardiac phantom with known left ventricular (LV) volumes and ejection fractions (EFs) was produced to evaluate quantitative measurements obtained from gated myocardial single-photon emission tomography (SPET). The 3-D gated cardiac phantom was designed and constructed to fit into the Data Spectrum anthropomorphic torso phantom. Flexible silicone membranes form the inner and outer walls of the simulated left ventricle. Simulated LV volumes can be varied within the range 45-200 ml. The LV volume curve has a smooth and realistic clinical shape that is produced by a specially shaped cam connected to a piston. A fixed 70-ml stroke volume is applied for EF measurements. An ECG signal is produced at maximum LV filling by a controller unit connected to the pump. This gated cardiac phantom will be referred to as the Amsterdam 3-D gated cardiac phantom, or, in short, the AGATE cardiac phantom. SPET data were acquired with a triple-head SPET system. Data were reconstructed using filtered back-projection following pre-filtering and further processed with the Quantitative Gated SPECT (QGS) software to determine LV volume and EF values. Ungated studies were performed to measure LV volumes ranging from 45 ml to 200 ml. The QGS-determined LV volumes were systematically underestimated. For different LV combinations, the stroke volumes measured were consistent at 60-61 ml for 8-frame studies and 63-65 ml for 16-frame studies. QGS-determined EF values were slightly overestimated between 1.25% EF units for 8-frame studies and 3.25% EF units for 16-frame studies. In conclusion, the AGATE cardiac phantom offers possibilities for quality control, testing and validation of the whole gated cardiac SPET sequence, and testing of different acquisition and processing parameters and software. (orig.)

  7. 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...... conducted by a trained interviewer. Results: Of the 173 patients in the study, 39 experienced phantom pain. The median age of patients who had experienced phantom pain was 45 years (range: 19–88). Follow-up time from eye amputation to participation in the investigation was 4 years (range: 2–46). Phantom...... scale, ranging from 0 to 100, was 36 (range: 1–89). One-third of the patients experienced phantom pain every day. Chilliness, windy weather and psychological stress/fatigue were the most commonly reported triggers for pain. Conclusions: Phantom pain after eye amputation is relatively common. The pain...

  8. PID - 3D: a software to develop mathematical human phantoms for use in computational dosimetry

    International Nuclear Information System (INIS)

    The PID-3D software, written in Visual C++, contains tools developed for building and editing of three-dimensional geometric figures formed of voxels (volume pixels). These tools were projected to be used, together with those already developed by the Grupo de Dosimetria Numerica (GDN/CNPq), such as the FANTOMAS and DIP software, in computational dosimetry of ionizing radiation. The main objective of this paper is to develop various voxel-based geometric solids to build voxel phantoms (meaning models), anthropomorphic or not. The domain of this technique of development of geometric solids is important for the GDN/CNPq, because it allows the use of just one Monte Carlo code to simulate the transportation, interaction and deposition of radiation in tomographic and mathematical phantoms. Building a particular geometric solid the user needs to inform to the PID-3D software, the location and the size of the parallelepiped that involves it. Each built solid can be saved in a binary file of the type SGI (file containing the size and the numeric values that constitutes the 3D matrix that represents the solid, commonly used by GDN/CNPq). The final mathematical phantom is built starting from these SGI files and the SGI file resulting constitutes a voxel phantom. With this approach the software's user does not have to manipulate the equations and inequalities of the solids that represent the organs and tissues of the phantom. The 3D-PID software, associated with the FANTOMAS and DIP software are tools produced by GDN/CNPq, providing a new technique for building of 3D scenes in dosimetric evaluations using voxel phantoms. To validate the PID-3D software one built, step by step, a phantom similar to the MIRD-5 stylized phantom. (author)

  9. Beam quality independent attenuation phantom for estimating patient exposure from x-ray automatic exposure controlled chest examinations

    International Nuclear Information System (INIS)

    The periodic assessment of exposures in diagnostic radiology is an important part of a comprehensive quality assurance program. The most frequent radiologic examination conducted in the United States is chest radiography. Automatic exposure controlled (AEC) techniques are often used for this exam, and a standard patient-equivalent chest phantom is useful when estimating patient exposures on such systems. This is of particular importance if exposures are to be compared among AEC systems with different entrance x-ray spectra. Such a phantom has been developed to facilitate surveys of the average patient exposure from AEC posteroanterior chest radiography. The phantom is relatively lightweight and easily transportable, sturdy and made of readily available and relatively inexpensive materials (Lucite and aluminum). It accurately simulates the primary and scatter transmission through the lung-field regions of a patient-equivalent anthropomorphic phantom for x-ray spectra typically used in chest radiography. A clinical evaluation has been conducted to verify the patient equivalence of the phantom. Measurements of patient entrance skin exposure were obtained for a large number of patients on a variety of x-ray systems operated in the AEC mode using one or both lung-field detectors. Comparison of these data with exposure estimates derived from the phantom indicate that the phantom attenuates the x-ray beam in such a way that it can be employed to accurately and consistently estimate the mean exposure of the average patient under a variety of radiographic conditions

  10. Simulated evaluation of an intraoperative surface modeling method for catheter ablation by a real phantom simulation experiment

    Science.gov (United States)

    Sun, Deyu; Rettmann, Maryam E.; Packer, Douglas; Robb, Richard A.; Holmes, David R.

    2015-03-01

    In this work, we propose a phantom experiment method to quantitatively evaluate an intraoperative left-atrial modeling update method. In prior work, we proposed an update procedure which updates the preoperative surface model with information from real-time tracked 2D ultrasound. Prior studies did not evaluate the reconstruction using an anthropomorphic phantom. In this approach, a silicone heart phantom (based on a high resolution human atrial surface model reconstructed from CT images) was made as simulated atriums. A surface model of the left atrium of the phantom was deformed by a morphological operation - simulating the shape difference caused by organ deformation between pre-operative scanning and intra-operative guidance. During the simulated procedure, a tracked ultrasound catheter was inserted into right atrial phantom - scanning the left atrial phantom in a manner mimicking the cardiac ablation procedure. By merging the preoperative model and the intraoperative ultrasound images, an intraoperative left atrial model was reconstructed. According to results, the reconstruction error of the modeling method is smaller than the initial geometric difference caused by organ deformation. As the area of the left atrial phantom scanned by ultrasound increases, the reconstruction error of the intraoperative surface model decreases. The study validated the efficacy of the modeling method.

  11. Application of a simple phantom in assessing the effects of dose reduction on image quality in chest radiography

    International Nuclear Information System (INIS)

    Purpose: Firstly, to evaluate a commercial chest phantom incorporating a quasi anthropomorphic insert by comparing exposure measurements on the phantom with those of actual patients and, secondly, to assess the value of the phantom for image quality and dose optimisation. Methods: In the first part of the study entrance surface doses (ESD), Beam transmission (BT), and optical density (OD) were obtained for 77 chest radiography patients and compared with measurements made from exposures of the phantom using the respective patient exposure factors from chest examination. Differences were assessed with a student t-test, while the Pearson's linear correlation coefficient was used to test for any linear relationship. The second part assessed the applicability of the phantom to image quality studies by investigating the effect, on the clarity and detectability of lung lesions made from gelatine, of reducing patient dose below current dose levels. Clarity of linear objects of different dimensions was also studied. Lesion detectability and clarity was assessed by four observers. The possibility of extending dose reduction below current dose levels (Dref) was assessed from comparison of doses that produced statistically significant differences in image quality from Dref. Results: Results show that, with the exception of entrance doses and beam transmission through the diaphragm (P > 0.05), differences in OD and beam transmission between patients and phantom were statistically significant (P ref produced significant changes in both clarity and detectability. Conclusion: Within limits posed by the observed differences, the phantom can be applied to image quality studies in diagnostic radiology.

  12. Infant Cardiac CT Angiography with 64-Slice and 256-Slice CT: Comparison of Radiation Dose and Image Quality Using a Pediatric Phantom

    OpenAIRE

    Lee, Yi-Wei; Yang, Ching-Ching; Mok, Greta S. P.; Wu, Tung-Hsin

    2012-01-01

    Background The aims of this study were to investigate the image quality and radiation exposure of pediatric protocols for cardiac CT angiography (CTA) in infants under one year of age. Methodology/Principal Findings Cardiac CTA examinations were performed using an anthropomorphic phantom representing a 1-year-old child scanned with non-electrocardiogram-gated (NG), retrospectively electrocardiogram-gated helical (RGH) and prospectively electrocardiogram-gated axial (PGA) techniques in 64-slic...

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

    OpenAIRE

    Om Prakash Gurjar; Surendra Prasad Mishra

    2015-01-01

    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...

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

    Science.gov (United States)

    Perov, S Yu; Bogacheva, E V

    2015-01-01

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

  15. Comparison of 2D and 3D Gamma calculations for an IMRT QA phantom

    International Nuclear Information System (INIS)

    Gamma index pass rates were evaluated for an anthropomorphic phantom using both 2D and 3D calculations. The phantom was irradiated with the traditional dosimetry insert loaded with radiochromic film and TLD, and then with a 3D dosimetry insert. A comparison with the calculated dose distribution showed that both the PRESAGE® dosimeter and the film and TLD system agreed with the plan to within 5% using 2D gamma index criteria. The 3D gamma index showed a slightly higher pass rate than the 2D gamma index at 3%/3mm, and comparable pass rates using more generous constraints. The acceptable number of pixels passing the tighter constraints (3%/3mm) might be dependent upon the choice between a 2D calculation versus a 3D calculation

  16. Who Sees Human? The Stability and Importance of Individual Differences in Anthropomorphism.

    Science.gov (United States)

    Waytz, Adam; Cacioppo, John; Epley, Nicholas

    2010-05-01

    Anthropomorphism is a far-reaching phenomenon that incorporates ideas from social psychology, cognitive psychology, developmental psychology, and the neurosciences. Although commonly considered to be a relatively universal phenomenon with only limited importance in modern industrialized societies-more cute than critical-our research suggests precisely the opposite. In particular, we provide a measure of stable individual differences in anthropomorphism that predicts three important consequences for everyday life. This research demonstrates that individual differences in anthropomorphism predict the degree of moral care and concern afforded to an agent, the amount of responsibility and trust placed on an agent, and the extent to which an agent serves as a source of social influence on the self. These consequences have implications for disciplines outside of psychology including human-computer interaction, business (marketing and finance), and law. Concluding discussion addresses how understanding anthropomorphism not only informs the burgeoning study of nonpersons, but how it informs classic issues underlying person perception as well. PMID:24839457

  17. DESIGN OF AN ANTHROPOMORPHIC UPPER LIMB EXOSKELETON ACTUATED BY BALL-SCREWS AND CABLES

    OpenAIRE

    Garrec, Philippe

    2010-01-01

    This paper presents the design of ABLE, an anthropomorphic upper limb exoskeleton integrally actuated by highly reversible ball-screw and cable (SCS standing for Screw-and-Cable-System) allowing true joint torque control without force sensor. Their unique kinematics allows their integration in the structure thanks to dedicated mechanical innovations such as the shoulder articulation and the forearm-wrist. The result is an anthropomorphic, lightweight, open architecture which avoids imprisonin...

  18. Anthropomorphism and Human Likeness in the Design of Robots and Human-Robot Interaction

    OpenAIRE

    Ge, Shuzi Sam; Khatib, Oussama; Cabibihan, John-John; Simmons, Reid; Williams, Mary-Anne; Fink, Julia

    2012-01-01

    In this literature review we explain anthropomorphism and its role in the design of socially interactive robots and human-robot interaction. We illus-trate the social phenomenon of anthropomorphism which describes people’s tendency to attribute lifelike qualities to objects and other non lifelike artifacts. We present theoretical backgrounds from social sciences, and integrate related work from robotics research, including results from experiments with social ro-bots. We present different app...

  19. Who Sees Human? The Stability and Importance of Individual Differences in Anthropomorphism

    OpenAIRE

    Waytz, Adam; Cacioppo, John; Epley, Nicholas

    2014-01-01

    Anthropomorphism is a far-reaching phenomenon that incorporates ideas from social psychology, cognitive psychology, developmental psychology, and the neurosciences. Although commonly considered to be a relatively universal phenomenon with only limited importance in modern industrialized societies—more cute than critical—our research suggests precisely the opposite. In particular, we provide a measure of stable individual differences in anthropomorphism that predicts three important consequenc...

  20. The phantom illusion.

    Science.gov (United States)

    Galmonte, Alessandra; Soranzo, Alessandro; Rudd, Michael E; Agostini, Tiziano

    2015-12-01

    It is well known that visible luminance gradients may generate contrast effects. In this work we present a new paradoxical illusion in which the luminance range of gradual transitions has been reduced to make them invisible. By adopting the phenomenological method proposed by Kanizsa, we have found that unnoticeable luminance gradients still generate contrast effects. But, most interestingly, we have found that when their width is narrowed, rather than generating contrast effects on the surrounded surfaces, they generate an assimilation effect. Both high- and low-level interpretations of this "phantom" illusion are critically evaluated. PMID:26505683

  1. High-Dose-Rate 192Ir Brachytherapy Dose Verification: A Phantom Study

    Directory of Open Access Journals (Sweden)

    Alireza Nikoofar

    2015-05-01

    Full Text Available Background: The high-dose-rate (HDR brachytherapy might be an effective tool for palliation of dysphagia. Because of some concerns about adverse effects due to absorbed radiation dose, it is important to estimate absorbed dose in risky organs during this treatment. Objectives: This study aimed to measure the absorbed dose in the parotid, thyroid, and submandibular gland, eye, trachea, spinal cord, and manubrium of sternum in brachytherapy in an anthropomorphic phantom. Materials and Methods: To measure radiation dose, eye, parotid, thyroid, and submandibular gland, spine, and sternum, an anthropomorphic phantom was considered with applicators to set thermoluminescence dosimeters (TLDs. A specific target volume of about 23 cm3 in the upper thoracic esophagus was considered as target, and phantom planned computed tomography (CT for HDR brachytherapy, then with a micro-Selectron HDR (192Ir remote after-loading unit. Results: Absorbed doses were measured with calibrated TLDs and were expressed in centi-Gray (cGy. In regions far from target (≥ 16 cm such as submandibular, parotid and thyroid glands, mean measured dose ranged from 1.65 to 5.5 cGy. In closer regions (≤ 16 cm, the absorbed dose might be as high as 113 cGy. Conclusions: Our study showed similar depth and surface doses; in closer regions, the surface and depth doses differed significantly due to the role of primary radiation that had imposed a high-dose gradient and difference between the plan and measurement, which was more severe because of simplifications in tissue inhomogeneity, considered in TPS relative to phantom.

  2. Computational modeling of the mathematical phantoms of the Brazilian woman to internal dosimetry calculations and for comparison of the absorbed fractions with specific reference women

    International Nuclear Information System (INIS)

    The theme of this work is the study of the concept of mathematical dummy - also called phantoms - used in internal dosimetry and radiation protection, from the perspective of computer simulations. In this work he developed the mathematical phantom of the Brazilian woman, to be used as the basis of calculations of Specific Absorbed Fractions (AEDs) in the body's organs and skeleton by virtue of goals with regarding the diagnosis or therapy in nuclear medicine. The phantom now developed is similar, in form, to Snyder phantom making it more realistic for the anthropomorphic conditions of Brazilian women. For so we used the Monte Carlo method of formalism, through computer modeling. As a contribution to the objectives of this study, it was developed and implemented the computer system cFAE - consultation Fraction Specific Absorbed, which makes it versatile for the user's query researcher

  3. Redefining prosthetic ankle mechanics: non-anthropomorphic ankle design.

    Science.gov (United States)

    LaPrè, Andrew K; Sup, Frank

    2013-06-01

    The moment transferred at the residual limb socket interface of transtibial amputees can be a limiting factor of the comfort and activity level of lower limb amputees. The high pressures seen can be a significant source of pain, as well as result in deep tissue damage. The compensation of the sound limbs causes an asymmetrical gait which can be a contributor of early onset osteoarthritis in the sound limbs. It has been shown that the moment transferred with conventional passive prostheses can be lowered in magnitude by aligning the tibia with ground reaction forces, but this limits the effectiveness of the device. With recent powered prosthetics designed to mimic the missing limb, power can be injected into the gait cycle, but can also be limited by this pressure threshold. This paper shows the results of calculations that suggest that altering the prosthetic ankle mechanism can reduce the socket interface moments by as much as 50%. This supports the development of an active non-anthropomorphic ankle prosthesis which reduces socket interface moments while still injecting substantial power levels into the gait cycle. PMID:24187257

  4. Anthropomorphic robot for recognition and drawing generalized object images

    Science.gov (United States)

    Ginzburg, Vera M.

    1998-10-01

    The process of recognition, for instance, understanding the text, written by different fonts, consists in the depriving of the individual attributes of the letters in the particular font. It is shown that such process, in Nature and technique, can be provided by the narrowing the spatial frequency of the object's image by its defocusing. In defocusing images remain only areas, so-called Informative Fragments (IFs), which all together form the generalized (stylized) image of many identical objects. It is shown that the variety of shapes of IFs is restricted and can be presented by `Geometrical alphabet'. The `letters' for this alphabet can be created using two basic `genetic' figures: a stripe and round spot. It is known from physiology that the special cells of visual cortex response to these particular figures. The prototype of such `genetic' alphabet has been made using Boolean algebra (Venn's diagrams). The algorithm for drawing the letter's (`genlet's') shape in this alphabet and generalized images of objects (for example, `sleeping cat'), are given. A scheme of an anthropomorphic robot is shown together with results of model computer experiment of the robot's action--`drawing' the generalized image.

  5. Enhancement of finger motion range with compliant anthropomorphic joint design.

    Science.gov (United States)

    Çulha, Utku; Iida, Fumiya

    2016-04-01

    Robotic researchers have been greatly inspired by the human hand in the search to design and build adaptive robotic hands. Especially, joints have received a lot of attention upon their role in maintaining the passive compliance that gives the fingers flexibility and extendible motion ranges. Passive compliance, which is the tendency to be employed in motion under the influence of an external force, is the result of the stiffness and the geometrical constraints of the joints that define the direction of the motion. Based on its building elements, human finger joints have multi-directional passive compliance which means that they can move in multiple axis of motion under external force. However, due to their complex anatomy, only simplified biomechanical designs based on physiological analysis are preferred in present day robotics. To imitate the human joints, these designs either use fixed degree of freedom mechanisms which substantially limit the motion axes of compliance, or soft materials that can deform in many directions but hinder the fingers' force exertion capacities. In order to find a solution that lies between these two design approaches, we are using anatomically correct finger bones, elastic ligaments and antagonistic tendons to build anthropomorphic joints with multi-directional passive compliance and strong force exertion capabilities. We use interactions between an index finger and a thumb to show that our joints allow the extension of the range of motion of the fingers up to 245% and gripping size to 63% which can be beneficial for mechanical adaptation in gripping larger objects. PMID:26891473

  6. Vertical Drop Testing and Simulation of Anthropomorphic Test Devices

    Science.gov (United States)

    Polanco, Michael A.; Littell, Justin D.

    2011-01-01

    A series of 14 vertical impact tests were conducted using Hybrid III 50th Percentile and Hybrid II 50th Percentile Anthropomorphic Test Devices (ATDs) at NASA Langley Research Center. The purpose of conducting these tests was threefold: to compare and contrast the impact responses of Hybrid II and Hybrid III ATDs under two different loading conditions, to compare the impact responses of the Hybrid III configured with a nominal curved lumbar spine to that of a Hybrid III configured with a straight lumbar spine, and to generate data for comparison with predicted responses from two commercially available ATD finite element models. The two loading conditions examined were a high magnitude, short duration acceleration pulse, and a low magnitude, long duration acceleration pulse, each created by using different paper honeycomb blocks as pulse shape generators in the drop tower. The test results show that the Hybrid III results differ from the Hybrid II results more for the high magnitude, short duration pulse case. The comparison of the lumbar loads for each ATD configuration show drastic differences in the loads seen in the spine. The analytical results show major differences between the responses of the two finite element models. A detailed discussion of possible sources of the discrepancies between the two analytical models is also provided.

  7. 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.

  8. SU-E-J-209: Geometric Distortion at 3T in a Commercial 4D MRI-Compatible Phantom

    Energy Technology Data Exchange (ETDEWEB)

    Fatemi-Ardekani, A; Wronski, M; Kim, A; Stanisz, G; Sarfehnia, A; Keller, B [Sunnybrook Health Sciences Centre, Toronto, ON (Canada)

    2015-06-15

    Purpose: There are very few commercial 4D phantoms that are marketed as MRI compatible. We are evaluating one such commercial phantom, made to be used with an MRI-Linear accelerator. The focus of this work is to characterize the geometric distortions produced in this phantom at 3T using 3 clinical MR pulse sequences. Methods: The CIRS MRI-Linac Dynamic Phantom (CIRSTM) under investigation in this study consists of a softwaredriven moving tumour volume within a thorax phantom body and enables dose accumulation by placing a dosimeter within the tumour volume. Our initial investigation is to evaluate the phantom in static mode prior to examining its 4D capability. The water-filled thorax phantom was scanned using a wide-bore Philips 3T Achieva MRI scanner employing a Thoracic xl coil and clinical 2D T1W FFE, 2D T1W TSE and 3D T1W TFE pulse sequences. Each of the MR image sets was rigidly fused with a reference CT image of the phantom employing a rigid registration with 6 degrees of freedom. Geometric distortions between the MR and CT image sets were measured in 3 dimensions at selected points along the periphery of the distortion grid embedded within the phantom body (11.5, 7.5 and 3 cm laterally, ant/post and sup/inf of magnetic isocenter respectively). Results: The maximal measured geometric distortions between the MR and reference CT points of interest were 0.9, 1.8 and 1.3 mm in the lateral, anteriorposterior and cranio-caudal directions, respectively. For all 3 spatial dimensions, the maximal distortions occurred for the FFE pulse sequence. Maximal distortions for the 2D FFE, 2D TSE and 3D TFE sequences were 1, 0.7 and 1.8 mm, respectively. Conclusion: Our initial static investigation of this phantom shows minimal geometric distortions at 3T along the periphery of the embedded grid. CIRS has provided us with a phantom at no charge for evaluation at 3 Tesla.

  9. Optimization and objective and subjective analysis of thorax image for computerized radiology; Otimizacao e analise objetiva e subjetiva de imagem de torax para radiologia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Velo, Alexandre F.; Miranda, Jose Ricardo A., E-mail: afvelo@ibb.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil). Inst. Biociencias. Dept. de Fisica e Biofisica; Pina, Diana R.; Ribeiro, Sergio M., E-mail: drpina@fmb.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil). Faculdade de Medicina. Dept. de Doencas Tropicais e Diagnostico por Imagem; Duarte, Sergio, E-mail: sbd@cbpf.br [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro,RJ (Brazil)

    2013-07-01

    This research aimed at optimizing computational chest radiographic images (in previous posterior projection-PA). To this end, we used a homogeneous patient equivalent phantom in Computational Imaging System calibration, in order to obtain a satisfactory noise signal relation for a diagnosis, adjusting to a minimum dose received by the patient. The techniques have been applied in an anthropomorphic phantom (RANDO). The images obtained were evaluated by a radiologist, which identified the best image to determine possible pathologies (fracture or pneumonia). The technique were quantified objectively (Detective Quantum Efficiency - DQE, Modulation Transfer Function MTF, Noise Power Spectrum, NPS). Comparing optimized techniques with the clinical routine, it is concluded that all provide doses below reference levels. However the choice of the best technique for viewing possible pneumonia and/or fracture, was determined based on the first 3D (Dose, Diagnostic, Dollar) and regarded as gold standard. This image presented a reduction of dose and loading of tube around 70.5% and 80% respectively when compared with the clinical routine.

  10. The NORMAN phantom vs. the BOMAB phantom: are they different?

    Science.gov (United States)

    Kramer, Gary H; Capello, Kevin; Phan, Quoc

    2008-04-01

    This paper describes the implementation of the NORMAN phantom with the Human Monitoring Laboratory's Monte Carlo simulator, the problems that were encountered, and their solution. The NORMAN phantom has been compared with the reference man BOMAB phantom in three different whole body counting geometries: a scanning detector system (WBC1), and two stand-up whole body counters (WBC2, WBC3) that have different reference points for their counting geometry. The average agreement (taken over all energies) of the two phantoms is approximately a factor of 1.15 on any given counting system. For the first two systems (WBC1, WBC2) the BOMAB has the highest counting efficiency, whereas it is reversed on the third system (WBC3). Considering the differences between the two phantoms, the agreement is good. PMID:18332727

  11. Numerical efficiency calibration of in vivo measurement systems. Monte Carlo simulations of in vivo measurement scenarios for the detection of incorporated radionuclides, including validation, analysis of efficiency-sensitive parameters and customized anthropomorphic voxel models

    International Nuclear Information System (INIS)

    Detector efficiency calibration of in vivo bioassay measurements is based on physical anthropomorphic phantoms that can be loaded with radionuclides of the suspected incorporation. Systematic errors of traditional calibration methods can cause considerable over- or underestimation of the incorporated activity and hence the absorbed dose in the human body. In this work Monte Carlo methods for radiation transport problem are used. Virtual models of the in vivo measurement equipment used at the Institute of Radiation Research, including detectors and anthropomorphic phantoms have been developed. Software tools have been coded to handle memory intensive human models for the visualization, preparation and evaluation of simulations of in vivo measurement scenarios. The used tools, methods, and models have been validated. Various parameters have been investigated for their sensitivity on the detector efficiency to identify and quantify possible systematic errors. Measures have been implemented to improve the determination of the detector efficiency in regard to apply them in the routine of the in vivo measurement laboratory of the institute. A positioning system has been designed and installed in the Partial Body Counter measurement chamber to measure the relative position of the detector to the test person, which has been identified to be a sensitive parameter. A computer cluster has been set up to facilitate the Monte Carlo simulations and reduce computing time. Methods based on image registration techniques have been developed to transform existing human models to match with an individual test person. The measures and methods developed have improved the classic detector efficiency methods successfully. (orig.)

  12. 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.

  13. Supernumerary phantom limb after stroke

    OpenAIRE

    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.

  14. [Therapy of phantom limb pain].

    Science.gov (United States)

    Schwarzer, Andreas; Zenz, Michael; Maier, Christoph

    2009-03-01

    About 80 % of all extremity amputations suffer from phantom limb pain following the operation. In this context, it is important to differentiate between painful phantom limb sensations, non-painful phantom limb sensations and residual limb pain. The pathophysiology of phantom limb pain is not fully understood. Current research findings ascribe a major pathophysiological role to cortical changes as well as a disturbed body perception. Peripheral and spinal mechanisms appear less relevant in the development of phantom limb pain. An essential part of the therapy is the pharmacological treatment with antidepressants, anticonvulsives and opioids. Another significant aspect of therapy is senso-motory training, important to mention here would be mirror therapy, lateralisation and motor imaging. In case of an elective amputation, an epidural or axiliar plexus catheter should be considered prior to the amputation. The perioperative treatment with ketamine is debated. PMID:19266417

  15. A dynamic phantom for computertomography

    International Nuclear Information System (INIS)

    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 quality assuarance measurements in computertomography. 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 annother 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 Computertomograph. (orig.)

  16. Optimization of dose radiation and image quality on computed tomography of thorax in adult women

    International Nuclear Information System (INIS)

    Full text: The objective of the study is the optimization of the dose (Dlp) and image quality in the exploration of adult women in studies of thorax with computed tomography (CT). The CT is a technique of exploration with high radiation doses to patients with an increase of the risk factors of developing cancer in the future, but X-rays are a very important medical diagnostic tool. We performed a retrospective survey of 50 female patients who had thorax tomography using the automatic protocol established by the manufacturer, a database of dose (Dlp), measures of patient A P and radiological parameters such as kV and m A was obtained. Subsequently, we carry out the prospective study with 30 patients with prescription of thorax tomography, scans were conducted with CT with reduced doses using manual techniques protocol of exploration while maintaining diagnostic image quality. The results show that the prospective study patients received doses lower than 30% on average. In general the dose patients were within the confidence interval of 95% of the levels of diagnostic reference (DRL) adopted by the European Community for CT and the most common value is 400 Dlp for thorax. Comparative image quality study was conducted using the protocol of the manufacturer and the manual protocol and image quality was diagnostic after dose reduction up to 30%. The reduction of radiation dose in female patients in studies of thorax CT helps to reduce risk factors of developing cancer later in life. A thorax tomography study includes the fibro-glandular tissue of the breast which is very sensitive to stochastic effects of radiation. (Author)

  17. Optimization of dose radiation and image quality on computed tomography of thorax in adult women

    Energy Technology Data Exchange (ETDEWEB)

    Cruz Z, G. R.; Casian C, G. [Hospital Juarez de Mexico, Av. IPN No. 5160, 07760 Mexico D. F. (Mexico); Gaona, E.; Franco E, J. G.; Molina F, N., E-mail: gaen1310@correo.xoc.uam.mx [Universidad Autonoma Metropolitana, Unidad Xochimilco, Calz. del Hueso 1100, 04960 Mexico D. F. (Mexico)

    2015-10-15

    Full text: The objective of the study is the optimization of the dose (Dlp) and image quality in the exploration of adult women in studies of thorax with computed tomography (CT). The CT is a technique of exploration with high radiation doses to patients with an increase of the risk factors of developing cancer in the future, but X-rays are a very important medical diagnostic tool. We performed a retrospective survey of 50 female patients who had thorax tomography using the automatic protocol established by the manufacturer, a database of dose (Dlp), measures of patient A P and radiological parameters such as kV and m A was obtained. Subsequently, we carry out the prospective study with 30 patients with prescription of thorax tomography, scans were conducted with CT with reduced doses using manual techniques protocol of exploration while maintaining diagnostic image quality. The results show that the prospective study patients received doses lower than 30% on average. In general the dose patients were within the confidence interval of 95% of the levels of diagnostic reference (DRL) adopted by the European Community for CT and the most common value is 400 Dlp for thorax. Comparative image quality study was conducted using the protocol of the manufacturer and the manual protocol and image quality was diagnostic after dose reduction up to 30%. The reduction of radiation dose in female patients in studies of thorax CT helps to reduce risk factors of developing cancer later in life. A thorax tomography study includes the fibro-glandular tissue of the breast which is very sensitive to stochastic effects of radiation. (Author)

  18. Phantom validation of coregistration of PET and CT for image-guided radiotherapy

    International Nuclear Information System (INIS)

    Radiotherapy treatment planning integrating positron emission tomography (PET) and computerized tomography (CT) is rapidly gaining acceptance in the clinical setting. Although hybrid systems are available, often the planning CT is acquired on a dedicated system separate from the PET scanner. A limiting factor to using PET data becomes the accuracy of the CT/PET registration. In this work, we use phantom and patient validation to demonstrate a general method for assessing the accuracy of CT/PET image registration and apply it to two multi-modality image registration programs. An IAEA (International Atomic Energy Association) brain phantom and an anthropomorphic head phantom were used. Internal volumes and externally mounted fiducial markers were filled with CT contrast and 18F-fluorodeoxyglucose (FDG). CT, PET emission, and PET transmission images were acquired and registered using two different image registration algorithms. CT/PET Fusion (GE Medical Systems, Milwaukee, WI) is commercially available and uses a semi-automated initial step followed by manual adjustment. Automatic Mutual Information-based Registration (AMIR), developed at our institution, is fully automated and exhibits no variation between repeated registrations. Registration was performed using distinct phantom structures; assessment of accuracy was determined from registration of the calculated centroids of a set of fiducial markers. By comparing structure-based registration with fiducial-based registration, target registration error (TRE) was computed at each point in a three-dimensional (3D) grid that spans the image volume. Identical methods were also applied to patient data to assess CT/PET registration accuracy. Accuracy was calculated as the mean with standard deviation of the TRE for every point in the 3D grid. Overall TRE values for the IAEA brain phantom are: CT/PET Fusion=1.71±0.62 mm, AMIR=1.13±0.53 mm; overall TRE values for the anthropomorphic head phantom are: CT/PET Fusion=1.66±0

  19. A Monte Carlo-based knee phantom for in vivo measurements of 241Am in bone

    International Nuclear Information System (INIS)

    Determination of internal contamination of 241Am can be done by direct counting of gamma emission using a Whole Body Counter. Due to the strong attenuation of the low-energy photons, it is advised to perform the measurement on bones surrounded by a thin layer of tissue. In vivo measurements are performed at CIEMAT using a system of four Low-Energy germanium (LE Ge) detectors calibrated with realistic anthropomorphic phantoms. As an alternative, Monte Carlo techniques are applied on voxel phantoms based on tomographic images to avoid the need of different physical phantoms for different radionuclides and organs. This technique is employed to study the convenience of americium measurements in the knee for the evaluation of the deposition in the whole skeleton. The spatial distribution of the photon fluence through a cylinder along the axis of the leg has been calculated to determine the best counting geometry. The detection efficiency is then calculated and the results are compared with those obtained using the physical phantom to validate the proposed method

  20. The impact of cardiac gating on the detection of coronary calcifications in dual-energy chest radiography: a phantom study

    Science.gov (United States)

    Sabol, John M.; Liu, Ray; Saunders, Rowland; Markley, Jonathan; Moreno, Nery; Seamans, John; Wiese, Scott; Jabri, Kadri; Gilkeson, Robert C.

    2006-03-01

    The detection of coronary calcifications with CT is generally accepted as a useful method for predicting early onset of coronary artery disease. Film-screen X-ray and fluoroscopy have also been shown to have high predictive value for coronary disease diagnosis, but have minimal sensitivity. Recently, flat-panel detectors capable of dual-energy techniques have enabled the separation of soft-tissue and bone from images. Clinical studies report substantially improved sensitivity for the detection of coronary calcifications using these techniques. However, heart motion causes minor artefacts from misregistration of both calcified and soft-tissue structures, resulting in inconsistent detection of calcifications. This research examines whether cardiac gating improves the reliability of calcification detection. Single-energy, gated, and non-gated dual-energy imaging techniques are examined in a dynamic phantom model. A gating system was developed to synchronize two dual-energy exposures to a specified phase of the cardiac cycle. The performance and repeatability of the gating system was validated with the use of a cyclical phantom. An anthropomorphic phantom was developed to simulate both cardiac and soft-tissue motion, and generate ECG-like output signals. The anthropomorphic phantom and motion artefact accuracy was verified by comparison with clinical images of patients with calcifications. The ability of observers to detect calcifications in non-gated, and gated techniques was compared through the use of an ROC experiment. Gating visibly reduces the effect of motion artifacts in the dual-energy images. Without gating, motion artefacts cause greater variability in calcification detection. Comparison of the average area-under-the-curve of the ROC curves show that gating significantly increases the accuracy of calcification detection. The effects of motion and gating on DE cardiac calcification detection have been demonstrated and characterized in a phantom model that

  1. Do cavies talk?: The effect of anthropomorphic books on children's knowledge about animals

    Directory of Open Access Journals (Sweden)

    PatriciaAGanea

    2014-04-01

    Full Text Available Many books for young children present animals in fantastical and unrealistic ways, as wearing clothes, talking and engaging in human-like activities. This research examined whether anthropomorphism in children’s books affects children’s learning and conceptions of animals, by specifically assessing the impact of depictions (a bird wearing clothes and reading a book and language (bird described as talking and as having human intentions. In Study 1, 3-, 4-, and 5-year-old children saw picture books featuring realistic drawings of a novel animal. Half of the children also heard factual, realistic language, while the other half heard anthropomorphized language. In Study 2, we replicated the first study using anthropomorphic illustrations of real animals. The results show that the language used to describe animals in books has an effect on children’s tendency to attribute human-like traits to animals, and that anthropomorphic storybooks affect younger children’s learning of novel facts about animals. These results indicate that anthropomorphized animals in books may not only lead to less learning but also influence children’s conceptual knowledge of animals.

  2. A new mammography dosimetric phantom

    International Nuclear Information System (INIS)

    Breast phantoms produced with tissue-equivalent materials are used in an attempt to simulate glandular and adipose tissues, in terms of X-ray attenuation and density. In this work, a set of breast tissue-equivalent phantoms (BTE phantoms) with semicircular shapes of different thicknesses and compositions were produced. Such phantoms may be used in the measurement of the incident air kerma (K i) and the mean glandular dose (D G) delivered to patients undergoing mammography. To characterise the materials used to produce the phantoms, a series of 17-keV X-ray attenuation coefficient measurements were performed. The carbon-nitrogen-hydrogen elemental composition and the densities of the tissue-equivalent materials were also determined and compared with values available in the literature. Linear attenuation coefficients of 0.724 and 0.923 cm-1 were determined, respectively, for adipose and glandular tissues. Such values agree with data available in the literature. On the basis of the results obtained in this work, it is suggested that BTE phantoms are used instead of polymethyl methacrylate phantoms to select exposure parameters (kV, mAs and target/filter combination) specific for breast glandularities from 0 to 50 % in the optimisation of doses in mammography. (authors)

  3. Coordination of leg swing, thorax rotations, and pelvis rotations during gait: The organisation of total body angular momentum

    NARCIS (Netherlands)

    Bruijn, Sjoerd M.; Meijer, Onno G.; van Dieën, Jaap H.; Kingma, Idsart; Lamoth, Claudine J.C.

    2008-01-01

    In walking faster than 3 km/h, transverse pelvic rotation lengthens the step ("pelvic step"). It is often assumed that the thorax then starts to counter rotate to limit total body angular momentum around the vertical. But the relative timing of pelvis and thorax rotation during gait is insufficientl

  4. 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. PMID:10714655

  5. Interaction Between Thorax, Lumbar, and Pelvis Movements in the Transverse Plane During Gait at Three Velocities

    NARCIS (Netherlands)

    Yang, Ya-Ting; Yoshida, Yasuyuki; Hortobagyi, Tibor; Suzuki, Shuji

    2013-01-01

    We determined the angular range of motion and the relative timing of displacement in the thorax, lumbar spine, and pelvis in the transverse plane during treadmill walking at three velocities. Nine healthy young females walked on a treadmill for three minutes at 0.40, 0.93, and 1.47 m/s. The position

  6. Training for thorax diagnostics. Systematic cardiopulmonary image analysis; Trainer Thoraxdiagnostik. Systematische kardiopulmonale Bildanalyse

    Energy Technology Data Exchange (ETDEWEB)

    Kirchner, Johannes [Allgemeines Krankenhaus Hagen gem.GmbH (Germany). Klinik fuer Diagnostische und Interventionelle Radiologie

    2010-07-01

    The training book on thorax diagnostics using image analysis is supposed to be a supplement to the usual textbooks based on comprehensive experiences of radiologists. The covered issues are the following: heart insufficiency, acute/ chronic bronchitis and pulmonary emphysema; pneumonia and tuberculosis; bronchial carcinoma; lung fibrosis, sarcoidosis and pneumoconiosis, pleural effusion and pneumothorax.

  7. Histologically benign but clinically malignant neoplasms in the thorax: CT–pathological overview

    International Nuclear Information System (INIS)

    The purpose of this article is to review the computed tomography (CT) and histopathological features of uncommon primary neoplasms of the thorax that can manifest clinically malignant features (multiplicity of pulmonary nodules, an invasive nature, and metastases or recurrence after surgery) with little evidence of histological malignancy.

  8. REML estimates of genetic parameters of sexual dimorphism for wing and thorax length in Drosophila melanogaster

    Indian Academy of Sciences (India)

    Sandrine Mignon-Grasteau; Jean David; Patricia Gibert; Hélène Legout; Georges Pétavy; Brigitte Moreteau; Catherine Beaumont

    2004-08-01

    Restricted maximum likelihood was used to estimate genetic parameters of male and female wing and thorax length in isofemale lines of Drosophila melanogaster, and results compared to estimates obtained earlier with the classical analysis of variance approach. As parents within an isofemale line were unknown, a total of 500 parental pedigrees were simulated and mean estimates computed. Full and half sibs were distinguished, in contrast to usual isofemale studies in which animals were all treated as half sibs and hence heritability was overestimated. Heritability was thus estimated at 0.33, 0.38, 0.30 and 0.33 for male and female wing length and male and female thorax length, respectively, whereas corresponding estimates obtained using analysis of variance were 0.46, 0.54, 0.35 and 0.38. Genetic correlations between male and female traits were 0.85 and 0.62 for wing and thorax length, respectively. Sexual dimorphism and the ratio of female to male traits were moderately heritable (0.30 and 0.23 for wing length, 0.38 and 0.23 for thorax length). Both were moderately and positively correlated with female traits, and weakly and negatively correlated with male traits. Such heritabilities confirmed that sexual dimorphism might be a fast evolving trait in Drosophila.

  9. A Simple Device for Measuring Static Compliance of Lung-Thorax Combine

    Science.gov (United States)

    Sircar, Sabyasachi

    2015-01-01

    Explaining the concept of lung compliance remains a challenge to the physiology teacher because it cannot be demonstrated easily in human subjects and all attempts until now have used only simulation models. A simple device is described in the present article to measure the compliance of the "lung-thorax" combine in human subjects with…

  10. Localized air foci in the lower thorax in the patients with pneumothorax: Skip pneumothoraces

    International Nuclear Information System (INIS)

    Purpose: To investigate the characteristics and imaging features of localized air foci in the lower thorax in patients with pneumothorax using thin-section multidetector computed tomography. Materials and methods: Of 10,547 consecutive CT examinations comprising the chest, the CT scans of 146 patients with ordinary pneumothoraces were identified and retrospectively evaluated. The study group included 110 male and 36 female patients (mean age, 50 years; range, 1–93 years). All examinations were performed at our institution between January 2009 and December 2009. Cause of pneumothorax was classified as traumatic or non-traumatic. Localized air foci in the lower thorax were defined as being localized air collections in the lower thorax that did not appear to be adjacent to the lung. If these criteria were met, the shape, size, location laterality, and number of foci were evaluated. Associations with trauma, sex, severity of the pneumothorax, and laterality were evaluated using the χ2 test. All P values <0.05 were considered significant. Results: Localized air foci in the lower thorax presented as slit-like or small ovoid air collections in the lowest part of the pleural space. These foci were observed in 79/146 (54.1%) patients. The traumatic pneumothoraces group showed a higher prevalence of these features than the non-traumatic group. Some foci that were situated in the anterior part mimicked the appearance of free intraperitoneal air. Conclusion: Patients with pneumothorax commonly had localized air foci in the lower thorax. Because such foci can mimic pneumoperitoneum, accurate recognition of them is required to avoid confusion with free intraperitoneal air, especially in traumatic cases

  11. Localized air foci in the lower thorax in the patients with pneumothorax: Skip pneumothoraces

    Energy Technology Data Exchange (ETDEWEB)

    Higuchi, Takeshi, E-mail: higuchi@hosp.niigata.niigata.jp [Department of Diagnostic Radiology, Niigata City General Hospital, 463-7 Chuo-ku, Shumoku, Niigata 950-1197 (Japan); Takahashi, Naoya, E-mail: nandtr@hosp.niigata.niigata.jp [Department of Diagnostic Radiology, Niigata City General Hospital, 463-7 Chuo-ku, Shumoku, Niigata 950-1197 (Japan); Kiguchi, Takao, E-mail: takakig@gmail.com [Department of Diagnostic Radiology, Niigata City General Hospital, 463-7 Chuo-ku, Shumoku, Niigata 950-1197 (Japan); Shiotani, Motoi, E-mail: Shiotani14@gmail.com [Department of Radiology, Niigata Cancer Center Hospital, 2-15-3 Chuo-ku, Kawagishicho, Niigata 951-8566 (Japan); Maeda, Haruo, E-mail: h-maeda@hosp.niigata.niigata.jp [Department of Diagnostic Radiology, Niigata City General Hospital, 463-7 Chuo-ku, Shumoku, Niigata 950-1197 (Japan)

    2013-08-15

    Purpose: To investigate the characteristics and imaging features of localized air foci in the lower thorax in patients with pneumothorax using thin-section multidetector computed tomography. Materials and methods: Of 10,547 consecutive CT examinations comprising the chest, the CT scans of 146 patients with ordinary pneumothoraces were identified and retrospectively evaluated. The study group included 110 male and 36 female patients (mean age, 50 years; range, 1–93 years). All examinations were performed at our institution between January 2009 and December 2009. Cause of pneumothorax was classified as traumatic or non-traumatic. Localized air foci in the lower thorax were defined as being localized air collections in the lower thorax that did not appear to be adjacent to the lung. If these criteria were met, the shape, size, location laterality, and number of foci were evaluated. Associations with trauma, sex, severity of the pneumothorax, and laterality were evaluated using the χ{sup 2} test. All P values <0.05 were considered significant. Results: Localized air foci in the lower thorax presented as slit-like or small ovoid air collections in the lowest part of the pleural space. These foci were observed in 79/146 (54.1%) patients. The traumatic pneumothoraces group showed a higher prevalence of these features than the non-traumatic group. Some foci that were situated in the anterior part mimicked the appearance of free intraperitoneal air. Conclusion: Patients with pneumothorax commonly had localized air foci in the lower thorax. Because such foci can mimic pneumoperitoneum, accurate recognition of them is required to avoid confusion with free intraperitoneal air, especially in traumatic cases.

  12. Robot arm based flat panel CT-guided electromagnetic tracked spine interventions: phantom and animal model experiments

    Energy Technology Data Exchange (ETDEWEB)

    Penzkofer, Tobias; Isfort, Peter; Bruners, Philipp; Mahnken, Andreas H. [RWTH Aachen University, Applied Medical Engineering, Helmholtz-Institute Aachen, Aachen (Germany); RWTH Aachen University, Department of Diagnostic Radiology, Aachen University Hospital, Aachen (Germany); Wiemann, Christian; Guenther, Rolf W. [RWTH Aachen University, Department of Diagnostic Radiology, Aachen University Hospital, Aachen (Germany); Kyriakou, Yiannis; Kalender, Willi A. [Friedrich-Alexander University of Erlangen-Nuremberg, Institute for Medical Physics, Erlangen (Germany); Schmitz-Rode, Thomas [RWTH Aachen University, Applied Medical Engineering, Helmholtz-Institute Aachen, Aachen (Germany)

    2010-11-15

    To evaluate accuracy and procedure times of electromagnetic tracking (EMT) in a robotic arm mounted flat panel setting using phantom and animal cadaveric models. A robotic arm mounted flat panel (RMFP) was used in combination with EMT to perform anthropomorphic phantom (n = 90) and ex vivo pig based punctures (n = 120) of lumbar facet joints (FJ, n = 120) and intervertebral discs (IVD, n = 90). Procedure accuracies and times were assessed and evaluated. FJ punctures were carried out with a spatial accuracy of 0.8 {+-} 0.9 mm (phantom) and 0.6 {+-} 0.8 mm (ex vivo) respectively. While IVD punctures showed puncture deviations of 0.6 {+-} 1.2 mm (phantom) and 0.5 {+-} 0.6 mm (ex vivo), direct and angulated phantom based punctures had accuracies of 0.8 {+-} 0.9 mm and 1.0 {+-} 1.3 mm. Planning took longer for ex vivo IVD punctures compared to phantom model interventions (39.3 {+-} 17.3 s vs. 20.8 {+-} 5.0 s, p = 0.001) and for angulated vs. direct phantom FJ punctures (19.7 {+-} 5.1 s vs. 28.6 {+-} 7.8 s, p < 0.001). Puncture times were longer for ex vivo procedures when compared to phantom model procedures in both FJ (37.9 {+-} 9.0 s vs. 23.6 {+-} 7.2 s, p = 0.001) and IVD punctures (43.9 {+-} 16.1 s vs. 31.1 {+-} 6.4 s, p = 0.026). The combination of RMFP with EMT provides an accurate method of navigation for spinal interventions such as facet joint punctures and intervertebral disc punctures. (orig.)

  13. Multimodal Phantom of Liver Tissue

    OpenAIRE

    Chmarra, Magdalena K.; Hansen, Rune; Mårvik, Ronald; Langø, Thomas

    2013-01-01

    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 reso...

  14. Concept development of a tendon arm manipulator and anthropomorphic robotic hand

    Science.gov (United States)

    Tolman, C. T.

    1987-01-01

    AMETEK/ORED inhouse research and development efforts leading toward a next-generation robotic manipulator arm and end-effector technology is summarized. Manipulator arm development has been directed toward a multiple-degree-of-freedom, flexible, tendon-driven concept referred to here as a Tendon Arm Manipulator (TAM). End-effector development has been directed toward a three-fingered, dextrous, tendon-driven, anthropomorphic configuration which is referred to as an Anthropomorphic Robotic Hand (ARH). Key technology issues are identified for both concepts.

  15. Anthropomorphism in Sign Languages: A Look at Poetry and Storytelling with a Focus on British Sign Language

    Science.gov (United States)

    Sutton-Spence, Rachel; Napoli, Donna Jo

    2010-01-01

    The work presented here considers some linguistic methods used in sign anthropomorphism. We find a cline of signed anthropomorphism that depends on a number of factors, including the skills and intention of the signer, the animacy of the entities represented, the form of their bodies, and the form of vocabulary signs referring to those entities.…

  16. New format for storage of voxel phantom, and exposure computer model EGS4/MAX to EGSnrc/MASH update

    Energy Technology Data Exchange (ETDEWEB)

    Leal Neto, Viriato [Departamento de Energia Nuclear (DEN). Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil); Instituto Federal de Educacao, Ciencia e Tecnologia de Pernambuco. Recife, PE (Brazil); Vieira, Jose W. [Escola Politecnica de Pernambuco. UPE, Recife, PE (Brazil); Lima, Fernando R.A., E-mail: falima@cnen.gov.br [Centro Regional de Ciencias Nucleares (CRCN/NE-CNEN-PE), Recife, PE (Brazil); Lima, Lindeval F., E-mail: lindeval@dmat.ufrr.br [Departamento de Matematica. Universidade Federal de Roraima (UFRR), Boa Vista, RR (Brazil)

    2011-07-01

    In order to estimate the dosage absorbed by those subjected to ionizing radiation, it is necessary to perform simulations using the exposure computational model (ECM). Such models are consists essentially of an anthropomorphic phantom and a Monte Carlo code (MC). The conjunction of a voxel phantom of the MC code is a complex process and often results in solving a specific problem. This is partly due to the way the phantom voxel is stored on a computer. It is usually required a substantial amount of space to store a static representation of the human body and also a significant amount of memory for reading and processing a given simulation. This paper presents a new way to store data concerning the geometry irradiated (similar to the technique of repeated structures used in the geometry of MCNP code), reducing by 52% the disk space required for storage when compared to the previous format applied by Grupo de Dosimetria Numerica (GDN/CNPq). On the other hand, research in numerical dosimetry leads to a constant improvement on the resolution of voxel phantoms leading thus to a new requirement, namely, to develop new estimates of dose. Therefore, this work also performs an update of the MAX (Male Adult voXel)/EGS4 ECM for the MASH (Adult MaleMeSH)/EGSnrc ECM and presents instances of dosimetric evaluations using the new ECM. Besides the update of the phantom and the MC code, the algorithm of the source used has also been improved in contrast to previous publications. (author)

  17. New format for storage of voxel phantom, and exposure computer model EGS4/MAX to EGSnrc/MASH update

    International Nuclear Information System (INIS)

    In order to estimate the dosage absorbed by those subjected to ionizing radiation, it is necessary to perform simulations using the exposure computational model (ECM). Such models are consists essentially of an anthropomorphic phantom and a Monte Carlo code (MC). The conjunction of a voxel phantom of the MC code is a complex process and often results in solving a specific problem. This is partly due to the way the phantom voxel is stored on a computer. It is usually required a substantial amount of space to store a static representation of the human body and also a significant amount of memory for reading and processing a given simulation. This paper presents a new way to store data concerning the geometry irradiated (similar to the technique of repeated structures used in the geometry of MCNP code), reducing by 52% the disk space required for storage when compared to the previous format applied by Grupo de Dosimetria Numerica (GDN/CNPq). On the other hand, research in numerical dosimetry leads to a constant improvement on the resolution of voxel phantoms leading thus to a new requirement, namely, to develop new estimates of dose. Therefore, this work also performs an update of the MAX (Male Adult voXel)/EGS4 ECM for the MASH (Adult MaleMeSH)/EGSnrc ECM and presents instances of dosimetric evaluations using the new ECM. Besides the update of the phantom and the MC code, the algorithm of the source used has also been improved in contrast to previous publications. (author)

  18. Calculation of normalised organ and effective doses to adult reference computational phantoms from contemporary computed tomography scanners

    International Nuclear Information System (INIS)

    The general-purpose Monte Carlo radiation transport code MCNPX has been used to simulate photon transport and energy deposition in anthropomorphic phantoms due to the x-ray exposure from the Philips iCT 256 and Siemens Definition CT scanners, together with the previously studied General Electric 9800. The MCNPX code was compiled with the Intel FORTRAN compiler and run on a Linux PC cluster. A patch has been successfully applied to reduce computing times by about 4%. The International Commission on Radiological Protection (ICRP) has recently published the Adult Male (AM) and Adult Female (AF) reference computational voxel phantoms as successors to the Medical Internal Radiation Dose (MIRD) stylised hermaphrodite mathematical phantoms that form the basis for the widely-used ImPACT CT dosimetry tool. Comparisons of normalised organ and effective doses calculated for a range of scanner operating conditions have demonstrated significant differences in results (in excess of 30%) between the voxel and mathematical phantoms as a result of variations in anatomy. These analyses illustrate the significant influence of choice of phantom on normalised organ doses and the need for standardisation to facilitate comparisons of dose. Further such dose simulations are needed in order to update the ImPACT CT Patient Dosimetry spreadsheet for contemporary CT practice. (author)

  19. SU-F-18C-08: A Validation Study of a Commercially Available Software Package's Absorbed Dose Estimates in a Physical Phantom

    International Nuclear Information System (INIS)

    Purpose: This study assesses the accuracy of the absorbed dose estimates from CT scans generated by Monte Carlo (MC) simulation using a commercially available radiation dose monitoring software program. Methods: Axial CT studies of an anthropomorphic abdomen phantom with dose bores at a central location and 4 peripheral locations were conducted using a fixed tube current at 120 kV. A 100 mm ion chamber and a 0.6 cc ion chamber calibrated at diagnostic energy levels were used to measure dose in the phantom at each of the 5 dose bore locations. Simulations using the software program's Monte Carlo engine were run using a mathematical model of the anthropomorphic phantom to determine conversion coefficients between the CTDIvol used for the study and the dose at the location of the dose bores. Simulations were conducted using both the software's generic CT beam model and a refined model generated using HVL and bow tie filter profile measurements made on the scanner used for the study. Results: Monte Carlo simulations completed using the generalized beam model differed from the measured conversion factors by an absolute value average of 13.0% and 13.8% for the 100 mm and 0.6 cc ion chamber studies, respectively. The MC simulations using the scanner specific beam model generated conversion coefficients that differed from the CTDIvol to measured dose conversion coefficients by an absolute value average of 7.3% and 7.8% for the 100 mm and 0.6 cc ion chamber cases, respectively. Conclusion: A scanner specific beam model used in MC simulations generates more accurate dose conversion coefficients in an anthropomorphic phantom than those generated with a generalized beam model. Agreement between measured conversion coefficients and simulated values were less than 20% for all positions using the universal beam model

  20. SU-F-18C-08: A Validation Study of a Commercially Available Software Package's Absorbed Dose Estimates in a Physical Phantom

    Energy Technology Data Exchange (ETDEWEB)

    Supanich, M [Rush University Medical Center, Chicago, IL (United States); Siegelman, J [Brigham and Women' s Hospital Harvard Medical School, Boston, MA (United States)

    2014-06-15

    Purpose: This study assesses the accuracy of the absorbed dose estimates from CT scans generated by Monte Carlo (MC) simulation using a commercially available radiation dose monitoring software program. Methods: Axial CT studies of an anthropomorphic abdomen phantom with dose bores at a central location and 4 peripheral locations were conducted using a fixed tube current at 120 kV. A 100 mm ion chamber and a 0.6 cc ion chamber calibrated at diagnostic energy levels were used to measure dose in the phantom at each of the 5 dose bore locations. Simulations using the software program's Monte Carlo engine were run using a mathematical model of the anthropomorphic phantom to determine conversion coefficients between the CTDIvol used for the study and the dose at the location of the dose bores. Simulations were conducted using both the software's generic CT beam model and a refined model generated using HVL and bow tie filter profile measurements made on the scanner used for the study. Results: Monte Carlo simulations completed using the generalized beam model differed from the measured conversion factors by an absolute value average of 13.0% and 13.8% for the 100 mm and 0.6 cc ion chamber studies, respectively. The MC simulations using the scanner specific beam model generated conversion coefficients that differed from the CTDIvol to measured dose conversion coefficients by an absolute value average of 7.3% and 7.8% for the 100 mm and 0.6 cc ion chamber cases, respectively. Conclusion: A scanner specific beam model used in MC simulations generates more accurate dose conversion coefficients in an anthropomorphic phantom than those generated with a generalized beam model. Agreement between measured conversion coefficients and simulated values were less than 20% for all positions using the universal beam model.

  1. Phantom Black Holes and Sigma Models

    OpenAIRE

    Azreg-Aïnou, Mustapha; Clément, Gérard; Fabris, Júlio C.; Rodrigues, Manuel E.

    2011-01-01

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

  2. Hepatic hydro thorax: patient with pleural effusion to the right presenting tracer migration to the contralateral thorax projection on early scintigraphic images

    Energy Technology Data Exchange (ETDEWEB)

    Ichiki, W.A.; Ribeiro, V.P.B.; Gusman, L.; Coura Filho, G.B.; Sapienza, M.T.; Ono, C.R; Watanabe, T.; Costa, P.L.A.; Hironaka, F.; Cerri, G.G.; Buchpiguel, C.A. [Universidade de Sao Paulo (FMUSP), SP (Brazil). Fac. de Medicina. Hospital das Clinicas

    2008-07-01

    Full text: Introduction: Hepatic hydrothorax is a significant pleural effusion, greater than 500 mL, that appears as a clinical manifestation of portal hypertension in patients with advanced cirrhosis, in the absence of cardiopulmonary disease. Its mechanisms may be explained by migration of ascitic fluid through diaphragm defects. Radioisotope scintigraphy may contribute for the diagnostic of hepatic hydrothorax. Case report: Female, 79 years old, with a history of hepatic cirrhosis due to hepatitis B virus, without primary pulmonary or heart disease. She presented worsening of clinical ascites and dyspnoea, and it was diagnosed an extensive right pleural effusion. She underwent a thoracocentesis with a drainage of 2000 mL of light yellow-citrine fluid with transudate features. The pleural effusion quickly relapsed, leading the hypothesis of a hepatic hydrothorax. A scintigraphy was requested to assess peritoneo-pleural shunt. A dose of 370 MBq (10 mCi) of {sup 99m}Tc sulfur colloid was instilled intraperitoneally. Static images involving the thorax and upper abdomen were acquired at 10, 20, 30 and 40 minutes and 4 hours after injection. At 10 minutes the radiotracer was seen on the left side of the thoracic region. The scintigraphy was repeated three days later, just after new thoracocentesis, due to the tracer progression to the left side of the thorax differed to the location of pleural effusion. Likewise, until 4 hours of the second study, the radiotracer was seen again on the left side of the thorax. However, a delayed image of 24 showed accumulation of the radiotracer in the right pleural cavity, confirming peritoneo-pleural shunt as cause of pleural effusion in this patient. Discussion: Hydrothorax is an uncommon complication in patients with decompensated hepatic cirrhosis. Its mechanisms are still not well elucidated, however, it is known that presence of defects in the diaphragm associated with the imbalance of ascitic fluid volume and the pleural

  3. Hepatic hydro thorax: patient with pleural effusion to the right presenting tracer migration to the contralateral thorax projection on early scintigraphic images

    International Nuclear Information System (INIS)

    Full text: Introduction: Hepatic hydrothorax is a significant pleural effusion, greater than 500 mL, that appears as a clinical manifestation of portal hypertension in patients with advanced cirrhosis, in the absence of cardiopulmonary disease. Its mechanisms may be explained by migration of ascitic fluid through diaphragm defects. Radioisotope scintigraphy may contribute for the diagnostic of hepatic hydrothorax. Case report: Female, 79 years old, with a history of hepatic cirrhosis due to hepatitis B virus, without primary pulmonary or heart disease. She presented worsening of clinical ascites and dyspnoea, and it was diagnosed an extensive right pleural effusion. She underwent a thoracocentesis with a drainage of 2000 mL of light yellow-citrine fluid with transudate features. The pleural effusion quickly relapsed, leading the hypothesis of a hepatic hydrothorax. A scintigraphy was requested to assess peritoneo-pleural shunt. A dose of 370 MBq (10 mCi) of 99mTc sulfur colloid was instilled intraperitoneally. Static images involving the thorax and upper abdomen were acquired at 10, 20, 30 and 40 minutes and 4 hours after injection. At 10 minutes the radiotracer was seen on the left side of the thoracic region. The scintigraphy was repeated three days later, just after new thoracocentesis, due to the tracer progression to the left side of the thorax differed to the location of pleural effusion. Likewise, until 4 hours of the second study, the radiotracer was seen again on the left side of the thorax. However, a delayed image of 24 showed accumulation of the radiotracer in the right pleural cavity, confirming peritoneo-pleural shunt as cause of pleural effusion in this patient. Discussion: Hydrothorax is an uncommon complication in patients with decompensated hepatic cirrhosis. Its mechanisms are still not well elucidated, however, it is known that presence of defects in the diaphragm associated with the imbalance of ascitic fluid volume and the pleural absorptive

  4. Generation of a head phantom according to the 95. percentile Chinese population data for evaluating the specific absorption rate by wireless communication devices

    International Nuclear Information System (INIS)

    A Chinese head phantom (CHP) is constructed for evaluating the specific absorption rate (SAR) by the wireless transceivers. The dimensions of the head phantom are within 4 % difference compared with the 95. percentile data from the China's standard. The shell's thickness and the configuration of the pinna are the same as those of the specific anthropomorphic mannequin (SAM). Three computable models for the mobile phones are generated and used in the SAR simulations with the SAM and the CHP. The results show that the simulated SAR from the SAM head is similar. Its morphological reason has been analysed. The authors discuss the conservativeness of the two head phantoms as well. The CHP can be used in the inter-laboratory evaluation for the SAR uncertainty. It can also provide the information for the SAR variability due to physical difference, which will benefit the maintenance and the harmonisation of the standards. (authors)

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

    International Nuclear Information System (INIS)

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

  6. [Phantom Study on Dose Reduction Using Iterative Reconstruction in Low-dose Computed Tomography for Lung Cancer Screening].

    Science.gov (United States)

    Minehiro, Kaori; Takata, Tadanori; Hayashi, Hiroyuki; Sakuda, Keita; Nunome, Haruka; Kawashima, Hiroko; Sanada, Shigeru

    2015-12-01

    We investigated dose reduction ability of an iterative reconstruction technology for low-dose computed tomography (CT) for lung cancer screening. The Sinogram Affirmed Iterative Reconstruction (SAFIRE) provided in a multi slice CT system, Somatom Definition Flash (Siemens Healthcare) was used. An anthropomorphic chest phantom (N-1, Kyoto Kagaku) was scanned at volume CT dose index (CTDIvol) of 0.50-11.86 mGy with 120 kV. For noise (standard deviation) and contrast-to-noise ratio (CNR) measurements, CTP486 and CTP515 modules in the Catphan (The Phantom Laboratory) were scanned. Radiological technologists were participated in the perceptual comparison. SAFIRE reduced the SD values by approximately 50% compared with filter back projection (FBP). The estimated dose reduction rates by SAFIRE determined from the perceptual comparison was approximately 23%, while 75% dose reduction rate was expected from the SD value reduction of 50%. PMID:26685831

  7. In phantom figures of merit for an epithermal beam produced by a D-D compact neutron generator

    International Nuclear Information System (INIS)

    Recently the BNCT (Boron Neutron Capture Therapy) Scientific Community renewed the interest in the development of compact neutron sources for in hospital BNCT in order to skip the problems related to the use of nuclear reactors and to increase the number of treated patients. This paper presents a feasibility study for the exploitation of a high power D-D compact neutron facility, designed at Lawrence Berkeley National Laboratory (Ca, USA), for the treatment of tumours with diffuse metastases, such as liver cancer. The MCNP code is used to carry out an accurate study of the epithermal column and to assess both the free beam parameters and the in phantom figures of merit to evaluate the beam effectiveness. Various Beam Shaping Assemblies are tested using different materials and geometrical shapes in order to optimize the therapeutic ratio. Finally, the dose profiles are calculated along the beam axis in the anthropomorphic phantom 'ADAM'. (author)

  8. Pengaruh Window Level Dan Window Width Pada Lung Window Dan Mediastinum Window Pada Kualitas Citra CT-Scan Thorax

    OpenAIRE

    Gaol, Syahnaro Lumban

    2015-01-01

    This Research of image CT-SCAN thorax with influence of window level and window width, to obtain, get value of window level and optimal window width lung window and mediastinum window, so that get image of CT-SCAN thorax which with image quality. Image of CT-SCAN thorax obtained for mediastinum window use window width 350, 400, 450, 500 HU. And Window level 50,100,150 HU. While for lung window use window width 1000,1100 HU. The window level - 500-,600,-700,-800,-900,-1000 HU, by three observe...

  9. Is this car looking at you? How anthropomorphism predicts fusiform face area activation when seeing cars.

    Directory of Open Access Journals (Sweden)

    Simone Kühn

    Full Text Available Anthropomorphism encompasses the attribution of human characteristics to non-living objects. In particular the human tendency to see faces in cars has long been noticed, yet its neural correlates are unknown. We set out to investigate whether the fusiform face area (FFA is associated with seeing human features in car fronts, or whether, the higher-level theory of mind network (ToM, namely temporoparietal junction (TPJ and medial prefrontal cortex (MPFC show a link to anthropomorphism. Twenty participants underwent fMRI scanning during a passive car-front viewing task. We extracted brain activity from FFA, TPJ and MPFC. After the fMRI session participants were asked to spontaneously list adjectives that characterize each car front. Five raters judged the degree to which each adjective can be applied as a characteristic of human beings. By means of linear mixed models we found that the implicit tendency to anthropomorphize individual car fronts predicts FFA, but not TPJ or MPFC activity. The results point to an important role of FFA in the phenomenon of ascribing human attributes to non-living objects. Interestingly, brain regions that have been associated with thinking about beliefs and mental states of others (TPJ, MPFC do not seem to be related to anthropomorphism of car fronts.

  10. The Eyes have it : Eye Tracking Analysis of Anthropomorphic Car Fronts using Spatiotemporal Scan Statistics

    OpenAIRE

    Purucker, Christian; Jan R. Landwehr; Sprott, David E.; Herrmann, Andreas

    2011-01-01

    Eye tracking has traditionally relied on regions of interest as a data source for analysis. Although widespread, this methodology is prone to several limitations. A new approach for eye tracking data analysis relying on spatiotemporal scan statistics is proposed and an exemplary experiment on anthropomorphic car front design is conducted.

  11. Unifying phantom inflation with late-time acceleration: scalar phantom-non-phantom transition model and generalized holographic dark energy

    OpenAIRE

    Nojiri, Shin'ichi; Odintsov, Sergei D.(Department of Physics, Nagoya University, Nagoya 464-8602, Japan)

    2005-01-01

    The unifying approach to early-time and late-time universe based on phantom cosmology is proposed. We consider gravity-scalar system which contains usual potential and scalar coupling function in front of kinetic term. As a result, the possibility of phantom-non-phantom transition appears in such a way that universe could have effectively phantom equation of state at early time as well as at late time. In fact, the oscillating universe may have several phantom and non-phantom phases. As a sec...

  12. Experimental dosimetric evaluation in pelvis phantom, subjected to prostate radiation therapy protocol at 15 MV Linac

    Energy Technology Data Exchange (ETDEWEB)

    Matos, Andrea Silva Dias de; Campos, Tarcisio P.R., E-mail: campos@nuclear.ufmg.b [Universidade Federal de Minas Gerais (DEN/UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear; Dias, Humberto Galvao [Centro de Radioterapia Hospital Luxemburgo, Belo Horizonte, MG (Brazil)

    2011-07-01

    Among the existing malignant neoplasia, the prostate cancer is most common among male population. Due to its high incidence and morbidity, there is a need for investment in advanced technology for better treatment associated with research and social mobilization to prevent the disease. As an efficient method of treatment for such tumor, radiation teletherapy brings favorable results for the patient, particularly when the cancer is diagnosed early. There are, however, the needs to assess the absorbed doses that reach the prostate in the radiation protocols in order to certify the treatment efficacy. The present research goal is to obtain the profile of absorbed dose distributed in a synthetic prostate on male pelvis phantom following a standard radiation therapy protocol. The methodology makes use of a NRI made phantom and a 15MV Linac accelerator. This phantom has anthropomorphic and anthropometric features containing the major internal organs, including bone, prostate, intestine, and bladder. The exposition was made in a 15 MV linear accelerator taken the isocenter in four fields as a 'BOX' of opposing beams. The dosimetry was prepared using GafChromic EBT type 2 radiochromic film and calibration in a solid water phantom. The radiochromic films were digitized on the Microtek Scan Maker 6900XL model scanner operating in the transmission mode and optical density readings based on RGB mode in the computer program Imagedig. The absorbance readings were performed in the spectrophotometer SP-220 mark BIOSPECTRO obtaining calibration curves generated by the collected data. The results reproduce the dose distribution generated in two orthogonal radiochromic films positioned onto the synthetic prostate. Discussions regarding the characteristics of the phantom and methods of irradiation in relation to the achieved dose profile will be addressed. (author)

  13. Experimental dosimetric evaluation in pelvis phantom, subjected to prostate radiation therapy protocol at 15 MV Linac

    International Nuclear Information System (INIS)

    Among the existing malignant neoplasia, the prostate cancer is most common among male population. Due to its high incidence and morbidity, there is a need for investment in advanced technology for better treatment associated with research and social mobilization to prevent the disease. As an efficient method of treatment for such tumor, radiation teletherapy brings favorable results for the patient, particularly when the cancer is diagnosed early. There are, however, the needs to assess the absorbed doses that reach the prostate in the radiation protocols in order to certify the treatment efficacy. The present research goal is to obtain the profile of absorbed dose distributed in a synthetic prostate on male pelvis phantom following a standard radiation therapy protocol. The methodology makes use of a NRI made phantom and a 15MV Linac accelerator. This phantom has anthropomorphic and anthropometric features containing the major internal organs, including bone, prostate, intestine, and bladder. The exposition was made in a 15 MV linear accelerator taken the isocenter in four fields as a 'BOX' of opposing beams. The dosimetry was prepared using GafChromic EBT type 2 radiochromic film and calibration in a solid water phantom. The radiochromic films were digitized on the Microtek Scan Maker 6900XL model scanner operating in the transmission mode and optical density readings based on RGB mode in the computer program Imagedig. The absorbance readings were performed in the spectrophotometer SP-220 mark BIOSPECTRO obtaining calibration curves generated by the collected data. The results reproduce the dose distribution generated in two orthogonal radiochromic films positioned onto the synthetic prostate. Discussions regarding the characteristics of the phantom and methods of irradiation in relation to the achieved dose profile will be addressed. (author)

  14. Dosimetry in brain tumor phantom at 15 MV 3D conformal radiation therapy

    International Nuclear Information System (INIS)

    Glioblastoma multiforme (GBM) is the most common, aggressive, highly malignant and infiltrative of all brain tumors with low rate of control. The main goal of this work was to evaluate the spatial dose distribution into a GBM simulator inside a head phantom exposed to a 15 MV 3D conformal radiation therapy in order to validate internal doses. A head and neck phantom developed by the Ionizing Radiation Research Group (NRI) was used on the experiments. Such phantom holds the following synthetic structures: brain and spinal cord, skull, cervical and thoracic vertebrae, jaw, hyoid bone, laryngeal cartilages, head and neck muscles and skin. Computer tomography (CT) of the simulator was taken, capturing a set of contrasted references. Therapy Radiation planning (TPS) was performed based on those CT images, satisfying a 200 cGy prescribed dose split in three irradiation fields. The TPS assumed 97% of prescribed dose cover the prescribed treatment volume (PTV). Radiochromic films in a solid water phantom provided dose response as a function of optical density. Spatial dosimetric distribution was generated by radiochromic film samples at coronal, sagittal-anterior and sagittal-posterior positions, inserted into tumor simulator and brain. The spatial dose profiles held 70 to 120% of the prescribed dose. In spite of the stratified profile, as opposed to the smooth dose profile from TPS, the tumor internal doses were within a 5% deviation from 214.4 cGy evaluated by TPS. 83.2% of the points with a gamma value of less than 1 (3%/3mm) for TPS and experimental values, respectively. At the tumor, measured at coronal section, a few dark spots in the film caused the appearance of outlier points in 13-15% of dose deviation percentage. And, as final conclusion, such dosimeter choice and the physical anthropomorphic and anthropometric phantom provided an efficient method for validating radiotherapy protocols

  15. Development of a voxel phantom specific for simulation of eye brachytherapy

    International Nuclear Information System (INIS)

    The ophthalmic brachytherapy involves inserting a plate with seeds of radioactive material in the patient's eye for the treatment of tumors. The radiation dose to be taken by the patient is prescribed by physicians and time of application of the material is calculated from calibration curves supplied by the manufacturers of the plates. To estimate the dose absorbed by the patient, in a series of diagnostic tests, it is necessary to perform simulations using a computational model of exposure. These models are composed primarily by a anthropomorphic phantom, and a Monte Carlo code. The coupling of a phantom voxel whole body to a Monte Carlo code is a complex process because the computer model simulations with exposure takes time, knowledge of the code used and various adjustments to be implemented. The problem is aggravated even more complex when you want to radiate one region of the body. In this work we developed a phantom, specifically the region containing the eyeball, from MASH (Male Adult voxel). This model was coupled to the Monte Carlo code EGSnrc (Electron Gamma Shower) together with an algorithm simulator source of I-125 , considering only its effect of higher energy range

  16. Validation of a mathematical phantom for dose assessment of radiological accidents

    International Nuclear Information System (INIS)

    Sealed radioactive sources are widely used in the industry with the purpose of well logging, non-destructive testing, food irradiation, process control systems, elemental analysis and others. Among the most used sources, it can mention: 137Cs, 60Co, 192Ir, 85Kr and Americium-Beryllium with radiation activities ranging between a few MegaBecquerels (MBq) to million of GBq, as the case of food irradiation. In general, these sources present sufficient activity to represent a significant health hazard when inadequately shielded or not handled according to proper safety procedures, producing radiation exposures to workers and to members of public. In cases of overexposure to ionizing radiation, an estimative of the dose received by victims of radiation accidents, as well as its distribution within the organism, can be provided by use an anthropomorphic phantom associates with a theoretical simulation Monte Carlo method to simulate the radioactive source and its interactions with the phantom. In this work is presented the validation results of application of a mathematical phantom modeled in Geant4, as a tool to reconstruct dose of radiological accidents due to external exposure. The results are compared with the dosimetry of real accidents. (author)

  17. Limiting CT radiation dose in children with craniosynostosis: phantom study using model-based iterative reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Kaasalainen, Touko; Lampinen, Anniina [University of Helsinki and Helsinki University Hospital, HUS Medical Imaging Center, Radiology, POB 340, Helsinki (Finland); University of Helsinki, Department of Physics, Helsinki (Finland); Palmu, Kirsi [University of Helsinki and Helsinki University Hospital, HUS Medical Imaging Center, Radiology, POB 340, Helsinki (Finland); School of Science, Aalto University, Department of Biomedical Engineering and Computational Science, Helsinki (Finland); Reijonen, Vappu; Kortesniemi, Mika [University of Helsinki and Helsinki University Hospital, HUS Medical Imaging Center, Radiology, POB 340, Helsinki (Finland); Leikola, Junnu [University of Helsinki and Helsinki University Hospital, Department of Plastic Surgery, Helsinki (Finland); Kivisaari, Riku [University of Helsinki and Helsinki University Hospital, Department of Neurosurgery, Helsinki (Finland)

    2015-09-15

    Medical professionals need to exercise particular caution when developing CT scanning protocols for children who require multiple CT studies, such as those with craniosynostosis. To evaluate the utility of ultra-low-dose CT protocols with model-based iterative reconstruction techniques for craniosynostosis imaging. We scanned two pediatric anthropomorphic phantoms with a 64-slice CT scanner using different low-dose protocols for craniosynostosis. We measured organ doses in the head region with metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters. Numerical simulations served to estimate organ and effective doses. We objectively and subjectively evaluated the quality of images produced by adaptive statistical iterative reconstruction (ASiR) 30%, ASiR 50% and Veo (all by GE Healthcare, Waukesha, WI). Image noise and contrast were determined for different tissues. Mean organ dose with the newborn phantom was decreased up to 83% compared to the routine protocol when using ultra-low-dose scanning settings. Similarly, for the 5-year phantom the greatest radiation dose reduction was 88%. The numerical simulations supported the findings with MOSFET measurements. The image quality remained adequate with Veo reconstruction, even at the lowest dose level. Craniosynostosis CT with model-based iterative reconstruction could be performed with a 20-μSv effective dose, corresponding to the radiation exposure of plain skull radiography, without compromising required image quality. (orig.)

  18. Limiting CT radiation dose in children with craniosynostosis: phantom study using model-based iterative reconstruction

    International Nuclear Information System (INIS)

    Medical professionals need to exercise particular caution when developing CT scanning protocols for children who require multiple CT studies, such as those with craniosynostosis. To evaluate the utility of ultra-low-dose CT protocols with model-based iterative reconstruction techniques for craniosynostosis imaging. We scanned two pediatric anthropomorphic phantoms with a 64-slice CT scanner using different low-dose protocols for craniosynostosis. We measured organ doses in the head region with metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters. Numerical simulations served to estimate organ and effective doses. We objectively and subjectively evaluated the quality of images produced by adaptive statistical iterative reconstruction (ASiR) 30%, ASiR 50% and Veo (all by GE Healthcare, Waukesha, WI). Image noise and contrast were determined for different tissues. Mean organ dose with the newborn phantom was decreased up to 83% compared to the routine protocol when using ultra-low-dose scanning settings. Similarly, for the 5-year phantom the greatest radiation dose reduction was 88%. The numerical simulations supported the findings with MOSFET measurements. The image quality remained adequate with Veo reconstruction, even at the lowest dose level. Craniosynostosis CT with model-based iterative reconstruction could be performed with a 20-μSv effective dose, corresponding to the radiation exposure of plain skull radiography, without compromising required image quality. (orig.)

  19. Heart-induced movements in the thorax as detected by MRI

    CERN Document Server

    Solberg, Lars Erik; Fosse, Erik; Hol, Per Kristian

    2014-01-01

    In order to provide information for the use of radar in diagnostics a qualitative map of movements in the thorax has been obtained. This map was based on magnetic resonance image sequences of a human thorax during suspended respiration. The movements were measured using two distinct techniques. Segmentation provided measures of aorta dilatation and displacements, and image edge detection indicated other movements. The largest heart movements were found in the anterior and left regions of the heart with in-plane displacements on the order of 1 cm and which caused lung vessels displacements on the order of 2-3mm especially on the left side due to the heart ventricular. Mechanical coupling between the heart and aorta caused aorta displacements and shape distortions. Despite this coupling, aorta dilatations most likely reflected blood pressure variations.

  20. Diagnosis of the thorax in the intensive-care ward: Digital radiography

    International Nuclear Information System (INIS)

    Only few reports have been published so far on the clinical use of digital luminescence radiography (DLR). We report on 3.000 X-ray examinations of the thorax in the intensive-care ward performed by us since a suitable system (Philips PCR) had been installed in December 1987. The following advantages must be pointed out in respect of using DLR in thoracic diagnosis in the intensive-care ward: No faulty exposures; the thorax can be X-rayed with the patient recumbent in bed, with lateral take; the image brightness is maintained at a constant level by histogram selection; electronic image processing and storage. Hence, DLR entails considerable improvement in X-ray diagnosis of intensive-care patients. (orig.)

  1. Organ and effective dose evaluation in diagnostic radiology based on in-phantom dose measurements with novel photodiode-dosemeters

    International Nuclear Information System (INIS)

    Organ and the effective doses of patients undergoing clinical X-ray examinations of chest and abdomen were evaluated with an anthropomorphic phantom and a new dosimetry system. The system was comprised of 34 pin photodiode dosemeters placed in/on particular tissues or organs of the anthropomorphic phantom, where the tissues and organs are defined by the International Commission on Radiological Protection (ICRP) to estimate the effective doses. Dosemeter signals were acquired on a personal computer directly, and converted into absorbed doses, from which the organ and the effective doses were evaluated on the computer. Our study showed that organ doses ranged from <0.01 to 0.72 mGy in routine X-ray radiography of chest and of abdomen and from 0.07 to 55.91 mGy in routine computed tomography (CT) examinations with current multi-slice CT scanners. The effective dose observed in the chest CT examination was approximately 300 times higher than that in chest radiography. (authors)

  2. Phantom Energy and Cosmic Doomsday

    CERN Document Server

    Caldwell, R R; Weinberg, N N; Caldwell, Robert R.; Kamionkowski, Marc; Weinberg, Nevin N.

    2003-01-01

    Cosmologists have long wondered whether the Universe will eventually re-collapse and end with a Big Crunch, or expand forever, becoming increasingly cold and empty. Recent evidence for a flat Universe, possibly with a cosmological constant or some other sort of negative-pressure dark energy, has suggested that our fate is the latter. However, the data may actually be pointing toward an astonishingly different cosmic end game. Here, we explore the consequences that follow if the dark energy is phantom energy, in which the sum of the pressure and energy density is negative. The positive phantom-energy density becomes infinite in finite time, overcoming all other forms of matter, such that the gravitational repulsion rapidly brings our brief epoch of cosmic structure to a close. The phantom energy rips apart the Milky Way, solar system, Earth, and ultimately the molecules, atoms, nuclei, and nucleons of which we are composed, before the death of the Universe in a ``Big Rip''.

  3. Experimental research on specific activity of 24Na using Chinese reference man phantom irradiated by 252Cf neutrons source

    International Nuclear Information System (INIS)

    Objective: To investigate the specific activity of '24Na per unit neutron fluence, AB/Φ,in blood produced for Chinese reference man irradiated by 252Cf neutron source,and to analyze the effects of scattering neutrons from ground,wall,and ceiling in irradiation site on it.Methods: A 252Cf neutron source of 3×108 n/s and the anthropomorphic phantom were used for experiments. The phantom was made from 4 mm thick of outer covering by perspex and the liquid tissue-equivalent substitute in it. The data of phantom dimensions fit into Chinese reference man.The weight ratios of H, N, O and C in substitute equal from source to long axis of phantom were 1.1, 2.1, 3.1 and 4.1 m, respectively. Both the neutron source and the position of xiphisternum of the phantom were 1.6 m above the floor. Results: The average specific activity of 24Na per unit neutron fluence was related to the irradiation-distances, d, and its maximum value, AB/ΦM, deduced by experimental data was about 1.85×10-7 Bq·cm2·g-1. Conclusions: The AB/ΦM corresponds to that of phantom irradiated by plane-parallel beams, and the value is about more 3% than that by BOMAB phantom reported in literature. It has shown that floor-(wall-)scattered neutrons in irradiation site have significant contribution to the specific activity of 24Na, but they contributed relatively little to the induced neutron doses. Consequently,using the specific activity of 24Na for assessing accidental neutron doses received by an individual, the contribution of scattered neutrons in accident site will lead dose to be overestimated, and need to be correct. (authors)

  4. Development of a external exposure computational model for studying of input dose in skin for radiographs of thorax and vertebral column

    International Nuclear Information System (INIS)

    The dosimetric measurements do not always happen directly in the human body. Therefore, these assessments can be performed using anthropomorphic models (phantoms) evidencing models computational exposure (MCE) using techniques of Monte Carlo Method for virtual simulations. These processing techniques coupled with more powerful and affordable computers make the Monte Carlo method one of the tools most used worldwide in radiation transport area. In this work, the Monte Carlo EGS4 program was used to develop a computer model of external exposure to study the entrance skin dose for chest and column X-radiography and, aiming to optimize these practices by reducing doses to patients, professionals involved and the general public. The results obtained experimentally with the electrometer Radcal, model 9015, associated with the ionization chamber for radiology model 10X5-6, showed that the proposed computational model can be used in quality assurance programs in radiodiagnostic, evaluating the entrance skin dose when varying parameters of the radiation beam such as kilo voltage peak (kVp), current-time product (mAs), total filtration and distance surface source (DFS), optimizing the practices in radiodiagnostic and meeting the current regulation

  5. Monte Carlo simulation of in-vivo measurement of lung contamination; Simulacion Monte Carlo de medida in-vivo de contaminacion en pulmon

    Energy Technology Data Exchange (ETDEWEB)

    Moraleda, M.; Gomez-Ros, J. M.; Lopez, M. A.; Navarro, J. F.; Broggio, D.

    2011-07-01

    This paper describes the technique used to simulate in-vivo measurement of lung contaminated with enriched uranium using an anthropomorphic phantom of thorax. This work was carried out as part of an international intercomparison between different institutions within collaborative actions EURADOS promoted.

  6. SU-E-I-24: Design and Fabrication of a Multi-Functional Neck and Thyroid Phantom for Medical Dosimetry and Calibration

    International Nuclear Information System (INIS)

    Purpose: The purpose of this study is the design and fabrication of a multipurpose anthropomorphic neck and thyroid phantom for use in medical applications (i.e. quality control of images in nuclear medicine, and dosimetry). Methods: The designed neck phantom is composed of seven elliptic cylindrical slices with semi-major axis of 14 and semi-minor axis of 12.5 cm, each having the thickness of 2cm. Thyroid gland, bony part of the neck, and the wind pipe were also built inside the neck phantom. Results: The phantom contains some removable plugs,inside and at its surface to accommodate the TLD chips with different shapes and dimensions, (i.e. rod, cylindrical and cubical TLD chips)for the purpose of medical dosimetry (i.e. in radiology, radiotherapy, and nuclear medicine). For the purpose of quality control of images in nuclear medicine, the removable thyroid gland was built to accommodate the radioactive iodine. The female and male thyroid glands were built in two sizes separately. Conclusion: The designed phantom is a multi-functional phantom which is applicable for dosimetry in diagnostic radiology, radiotherapy, and quality control of images in nuclear medicine

  7. Calibration of a total body potassium monitor with an anthropometric phantom

    International Nuclear Information System (INIS)

    Full text: An anthropomorphic phantom was used to calibrate a supine geometry sodium iodide total body potassium monitor. Correction factors accommodating variability in subject size were empirically determined. Measurements on 10 males of weight 59-96 kg, height 161-184 cm and 12 females of weight 58-89 kg, height 153-175 cm, showed that the 40K calibration factor [F counts s-1 (g of potassium)-1] was significantly correlated (r=0.82, p0.5, indicating comparable accuracy to 42K-based calibration procedures. Fat-free mass determined from the potassium measurements of 16 subjects correlated significantly with fat-free mass estimated from skinfold thickness (r=0.98, p42K-based methods of calibrating total body potassium monitors

  8. Membership function used to construction of a hand homogeneous phantom; Aplicacao de funcoes de pertinencia na construcao de fantoma de mao

    Energy Technology Data Exchange (ETDEWEB)

    Pavan, Ana Luiza Menegatti; Alvarez, Matheus; Alves, Allan Felipe Fattori; Rosa, Maria Eugenia Dela; Miranda, Jose Ricardo de Arruda [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil). Instituto de Biociencias; Pina, Diana Rodrigues [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil). Departamento de Doencaas Tropicais e Diagnostico por Imagem; Duarte, Sergio Barbosa [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)

    2014-08-15

    Fractures and dislocations of the hand are some injuries most frequently encountered in trauma of the musculoskeletal system. In evaluating these lesions, in addition to physical examination, radiography, in at least two incidents, is the investigation of choice, and rarely is necessary the help of other images to establish the diagnosis and treatment. The image quality of X-ray examination is therefore essential. In this study, a homogeneous phantom hand was developed to be used in the optimization of images from hand using computed radiography system process. In this procedure were quantified thicknesses of different tissues that constitute an anthropomorphic phantom hand. To perform the classification and quantification of tissue was applied membership functions for histograms of CT scans. The same procedure was adopted for retrospective examinations of 30 patients of the Hospital das Clinicas, Botucatu Medicine School, UNESP (HCFMB-UNESP). The results showed agreement between the thicknesses of tissues that make up the anthropomorphic phantom and sampling of patients, presenting variations between 12.63% and 6.48% for soft tissue and bone, respectively. (author)

  9. Diversification of existing reference phantoms in nuclear medicine: Calculation of specific absorbed fractions for 21 mathematical phantoms and validation through dose estimates resulting from the administration of (18)F-FDG.

    Science.gov (United States)

    Blaickner, Matthias; Kindl, Peter

    2008-12-01

    Current dose assessment in nuclear medicine patient studies relies on published S-values, which are, in turn, based on calculated specific absorbed fractions (SAFs) available for a limited number of anthro-pomorphic computational phantoms. In order to take the individual physiognomy of patients more into account, this study aimed to broaden the supply of phantoms and their respective SAFs. An ensemble of 21 mathematical phantoms was submitted to the Monte Carlo Code MCNP4c2 for the purpose of calculation of SAFs for annihilation radiation. These values were incorporated into an internal dose assessment following the Medical Internal Radiation Dose (MIRD) schema and relying on published biokinetic data for intravenous administration of (18)F-FDG. The results were compared with data from the ICRP, MIRD reports and concurrent calculations with OLINDA/EXM. A very good agreement with sources relying on the SAFs of Cristy and Eckerman (i.e., the ICRP and OLINDA/EXM) was observed, with the absorbed dose in lung being the only exception. In the case of dose to red marrow, the King Spiers factors were omitted in the three-factor approximation, which led to a precise accordance with the Cristy/Eckerman values. Summarizing, one can say that the coincidence with published data justifies the method chosen and demonstrates successfully the expansion of available reference phantoms for dose assessment in nuclear medicine. PMID:19111050

  10. SU-E-I-48: The Behavior of AEC in Scan Regions Outside the Localizer Radiograph FOV: An In Phantom Study of CT Systems From Four Vendors

    Energy Technology Data Exchange (ETDEWEB)

    Supanich, M [Rush University Medical Center, Chicago, IL (United States); Bevins, N [Henry Ford Health System, Detroit, MI (United States)

    2014-06-01

    Purpose: This review of scanners from 4 major manufacturers examines the clinical impact of performing CT scans that extend into areas of the body that were not acquired in the CT localizer radiograph. Methods: Anthropomorphic chest and abdomen phantoms were positioned together on the tables of CT scanners from 4 different vendors. All of the scanners offered an Automatic Exposure Control (AEC) option with both lateral and axial tube current modulation. A localizer radiograph was taken covering the entire extent of both phantoms and then the scanner's Chest-Abdomen-Pelvis (CAP) study was performed with the clinical AEC settings employed and the scan and reconstruction range extending from the superior portion of the chest phantom through the inferior portion of the abdomen phantom. A new study was then initiated with a localizer radiograph extending the length of the chest phantom (not covering the abdomen phantom). The same CAP protocol and AEC settings were then used to scan and reconstruct the entire length of both phantoms. Scan parameters at specific locations in the abdomen phantom from both studies were investigated using the information contained in the DICOM metadata of the reconstructed images. Results: The AEC systems on all scanners utilized different tube current settings in the abdomen phantom for the scan completed without the full localizer radiograph. The AEC system behavior was also scanner dependent with the default manual tube current, the maximum tube current and the tube current at the last known position observed as outcomes. Conclusion: The behavior of the AEC systems of CT scanners in regions not covered by the localizer radiograph is vendor dependent. To ensure optimal image quality and radiation exposure it is important to include the entire planned scan region in the localizer radiograph.

  11. Born-Infeld Phantom Gravastars

    OpenAIRE

    Bilic, Neven; Tupper, Gary B.; Viollier, Raoul D.

    2005-01-01

    We construct new gravitational vacuum star solutions with a Born-Infeld phantom replacing the de Sitter interior. The model allows for a wide range of masses and radii required by phenomenology, and can be motivated from low energy string theory.

  12. Phantoms for calibrating albedo neutron dosimeters

    International Nuclear Information System (INIS)

    The lack of a standardized phantom was suspected to be the cause of some failures in a pilot study of dosimetry performance. Therefore a study was conducted to determine the effect of phantom size, shape and composition on the response of an albedo dosemeter. Dosemeters were exposed in air and on 15 different phantoms made of either polyethylene, Lucite or water. Results showed that the geometry of the phantom affects albedo readings, even for very large phantoms. No difference was found in readings for phantoms of different material when the geometry remained the same. It is concluded that in performance tests a phantom should be used that gives readings similar to those obtained with the phantom used by the testing laboratory. If another type is used the appropriate correction factor should be applied. The results of this study can be used to determine the correction factor. (author)

  13. Psychophysical correlates of phantom limb experience.

    OpenAIRE

    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 intens...

  14. 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.

  15. Coupled phantom field in loop quantum cosmology

    OpenAIRE

    Gumjudpai, Burin

    2007-01-01

    A model of phantom scalar field dark energy under exponential potential coupling to barotropic dark matter fluid in loop quantum cosmology is addressed here. We derive a closed-autonomous system for cosmological dynamics in this scenario. The expansion in loop quantum universe has a bounce even in presence of the phantom field. The greater decaying from dark matter to dark phantom energy results in greater energy storing in the phantom field. This results in further turning point of the field...

  16. Whole body counter calibration using Monte Carlo modeling with an array of phantom sizes based on national anthropometric reference data

    International Nuclear Information System (INIS)

    During construction of the whole body counter (WBC) at the Children's Nutrition Research Center (CNRC), efficiency calibration was needed to translate acquired counts of 40K to actual grams of potassium for measurement of total body potassium (TBK) in a diverse subject population. The MCNP Monte Carlo n-particle simulation program was used to describe the WBC (54 detectors plus shielding), test individual detector counting response, and create a series of virtual anthropomorphic phantoms based on national reference anthropometric data. Each phantom included an outer layer of adipose tissue and an inner core of lean tissue. Phantoms were designed for both genders representing ages 3.5 to 18.5 years with body sizes from the 5th to the 95th percentile based on body weight. In addition, a spherical surface source surrounding the WBC was modeled in order to measure the effects of subject mass on room background interference. Individual detector measurements showed good agreement with the MCNP model. The background source model came close to agreement with empirical measurements, but showed a trend deviating from unity with increasing subject size. Results from the MCNP simulation of the CNRC WBC agreed well with empirical measurements using BOMAB phantoms. Individual detector efficiency corrections were used to improve the accuracy of the model. Nonlinear multiple regression efficiency calibration equations were derived for each gender. Room background correction is critical in improving the accuracy of the WBC calibration.

  17. Whole body counter calibration using Monte Carlo modeling with an array of phantom sizes based on national anthropometric reference data

    Science.gov (United States)

    Shypailo, R. J.; Ellis, K. J.

    2011-05-01

    During construction of the whole body counter (WBC) at the Children's Nutrition Research Center (CNRC), efficiency calibration was needed to translate acquired counts of 40K to actual grams of potassium for measurement of total body potassium (TBK) in a diverse subject population. The MCNP Monte Carlo n-particle simulation program was used to describe the WBC (54 detectors plus shielding), test individual detector counting response, and create a series of virtual anthropomorphic phantoms based on national reference anthropometric data. Each phantom included an outer layer of adipose tissue and an inner core of lean tissue. Phantoms were designed for both genders representing ages 3.5 to 18.5 years with body sizes from the 5th to the 95th percentile based on body weight. In addition, a spherical surface source surrounding the WBC was modeled in order to measure the effects of subject mass on room background interference. Individual detector measurements showed good agreement with the MCNP model. The background source model came close to agreement with empirical measurements, but showed a trend deviating from unity with increasing subject size. Results from the MCNP simulation of the CNRC WBC agreed well with empirical measurements using BOMAB phantoms. Individual detector efficiency corrections were used to improve the accuracy of the model. Nonlinear multiple regression efficiency calibration equations were derived for each gender. Room background correction is critical in improving the accuracy of the WBC calibration.

  18. 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.  

  19. Phantom Dark Energy and its Cosmological Consequences

    OpenAIRE

    Dabrowski, Mariusz P.

    2007-01-01

    I discuss the dark energy characterized by the violation of the null energy condition ($\\varrho + p \\geq 0$), dubbed phantom. Amazingly, it is admitted by the current astronomical data from supernovae. We discuss both classical and quantum cosmological models with phantom as a source of matter and present the phenomenon called phantom duality.

  20. 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…

  1. Phantom Inflation and Primordial Perturbation Spectrum

    OpenAIRE

    Piao, Yun-Song; Zhang, Yuan-Zhong

    2004-01-01

    In this paper we study the inflation model driven by the phantom field. We propose a possible exit from phantom inflation to our observational cosmology by introducing an additional normal scalar field, similar to hybrid inflation model. Then we discuss the primordial perturbation spectra from various phantom inflation models and give an interesting compare with those of normal scalar field inflation models.

  2. SU-E-J-81: Interplay Effect in Non-Gated Dynamic Treatment Delivery of a Lung Phantom with Simulated Respiratory Motion

    Energy Technology Data Exchange (ETDEWEB)

    Desai, V; Fagerstrom, J; Bayliss, A; Kissick, M [University of Wisconsin, Madison, WI (United States)

    2014-06-01

    Purpose: To quantify the interplay effect in non-gated VMAT external beam delivery using realistic, clinically relevant 3D motion in an anthropomorphic lung phantom, and to determine if adding margins is sufficient to account for motion or if gating is required in all cases. Methods: A 4D motion stage was used to move a Virtual Water (VW) lung target containing a piece of radiochromic EBT3 film in an anthropomorphic chest phantom. A five-arc stereotactic body radiation therapy (SBRT) treatment was planned using a CT scan of the phantom in its stationary position, using planning parameters chosen to push the optimizer to achieve a highly-modulated plan. Two scenarios were delivered using a Varian TrueBeam: the first was delivered with the phantom and target both stationary and the second was delivered with the phantom stationary but the target moving in a realistic, irregular 3D elliptical pattern. A single piece of 4×4 cm{sup 2} film was used per fraction, located in the central coronal plane of the target. Film was calibrated on a 6 MV beam with dose values from 0.20 to 20 Gy. Results: Preliminary test films were analyzed in ImageJ and MatLab software. Dose maps were calculated on a central region of interest (ROI) delineated on both the motion-induced and stationary films. Both static and dynamic film dose maps agreed with planning values within acceptable uncertainty. Conclusion: Including a large number of arcs in a clinically realistic SBRT treatment could reduce the effect of motion interplay due to averaging. Because all clinics do not employ multiple arcs for SBRT lung treatments, it is still important to consider the effects of motion on treatment delivery. Further analysis on the treatment films, as well as a broader investigation other planning parameters, will be conducted.

  3. Assessing patient dose in interventional fluoroscopy using patient-dependent hybrid phantoms

    Science.gov (United States)

    Johnson, Perry Barnett

    Interventional fluoroscopy uses ionizing radiation to guide small instruments through blood vessels or other body pathways to sites of clinical interest. The technique represents a tremendous advantage over invasive surgical procedures, as it requires only a small incision, thus reducing the risk of infection and providing for shorter recovery times. The growing use and increasing complexity of interventional procedures, however, has resulted in public health concerns regarding radiation exposures, particularly with respect to localized skin dose. Tracking and documenting patient-specific skin and internal organ dose has been specifically identified for interventional fluoroscopy where extended irradiation times, multiple projections, and repeat procedures can lead to some of the largest doses encountered in radiology. Furthermore, inprocedure knowledge of localized skin doses can be of significant clinical importance to managing patient risk and in training radiology residents. In this dissertation, a framework is presented for monitoring the radiation dose delivered to patients undergoing interventional procedures. The framework is built around two key points, developing better anthropomorphic models, and designing clinically relevant software systems for dose estimation. To begin, a library of 50 hybrid patient-dependent computational phantoms was developed based on the UF hybrid male and female reference phantoms. These phantoms represent a different type of anthropomorphic model whereby anthropometric parameters from an individual patient are used during phantom selection. The patient-dependent library was first validated and then used in two patient-phantom matching studies focused on cumulative organ and local skin dose. In terms of organ dose, patient-phantom matching was shown most beneficial for estimating the dose to large patients where error associated with soft tissue attenuation differences could be minimized. For small patients, inherent difference

  4. Analysis of the IHC Adaptation for the Anthropomorphic Speech Processing Systems

    Directory of Open Access Journals (Sweden)

    Petrovsky Alexander A

    2005-01-01

    Full Text Available We analyse the properties of the physiological model of the adaptive behaviour of the chemical synapse between inner hair cells (IHC and auditory neurons. On the basis of the performed analysis, we propose equivalent structures of the model for implementation in the digital domain. The main conclusion of the analysis is that the synapse reservoir model is equivalent in its properties to the signal-dependent automatic gain-control mechanism. We plot guidelines for creation of artificial anthropomorphic algorithms, which exploit properties of the original synapse model. This paper also presents a concise description of the experiments, which prove the presence of the positive effect from the introduction of the depicted anthropomorphic algorithm into feature extraction of the automated speech recognition engine.

  5. Comparative breast phantom studies of tomographic scintimammography performed with PET and SPECT

    International Nuclear Information System (INIS)

    Aim: Comparative breast phantom studies were performed of tomographic scintimammography by means of Single Photon Emission Computed Tomography (SPECT) with NaI(Tl) detectors vs. Positron Emission Tomography with a dedicated scanner utilizing BGO detector ring (PET) or a dual-head gamma with NaI(Tl) detectors capable of Positron Emission Coincidence Imaging (PECI). Materials and methods: A female thorax phantom was used. Activities of the 'myocardium', 'thorax', 'liver' and 'breasts' were adjusted to emulate the count rates observed with patients. Hollow plastic spheres, imitating hot lesions (1.5-20 ml), filled with radioactive saline were inserted in the center of each 'breast'. The activities in the 'lesions' were varied in the 1.5' to 12' range above the 'breast' background. SPECT data were acquired with Tc-99m using gamma cameras with NaI(Tl) detectors. A modified FBP (CODE) and OSEM reconstruction algorithms were used to render SPECT tomographic images. PET (GE Advance with BGO) and PECI (Siemens E.CAM with NaI(Tl)) scans were acquired using F-18 FDG. Vendor supplied reconstruction algorithms were used. Results: The reconstructed hot 'lesions' contrast and resolution were obtained. Image quality obtained can be ranked as follows: (1) PET (BGO), (2) PECI (NaI(Tl)), (3) NaI(Tl) SPECT. Conclusion: Assuming comparable uptake values of Tc-99m-sestamibi and F-18 FDG, PET seems to be a superior methodology in visualization of simulated breast lesions as compared to SPECT and PECI. All these tomographic methods appear to be promising adjunct to x-ray mammography in difficult to interpret cases

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

    Science.gov (United States)

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

    2014-01-01

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

  7. Anthropomorphism and Advertising Effectiveness: Moderating Roles of Product Involvement and The Type of Consumer Need

    OpenAIRE

    BAŞFIRINCI, Cigdem; ÇİLİNGİR, Zuhal

    2015-01-01

    Abstract. The goal of this study is to explore that whether using anthropomorphism in ads stimulates active information processing by increasing attention paid to the brand and creates some positive results on brand recall and attitude toward the brand. In this context, moderating roles of involvement level and product type were also investigated. Using experimental design, hypotheses were tested in two product groups. Offering important insights to practitioners to build an effective adverti...

  8. Flexydos3D: A new deformable anthropomorphic 3D dosimeter readout with optical CT scanning

    International Nuclear Information System (INIS)

    A new deformable polydimethylsiloxane (PDMS) based dosimeter is proposed that can be cast in an anthropomorphic shape and that can be used for 3D radiation dosimetry of deformable targets. The new material has additional favorable characteristics as it is tissue equivalent for high-energy photons, easy to make and is non-toxic. In combination with dual wavelength optical scanning, it is a powerful dosimeter for dose verification of image gated or organ tracked radiotherapy with moving and deforming targets

  9. AR-601 anthropomorphic robot modeling and virtualization toolset for research and education purposes

    Science.gov (United States)

    Sirazetdinov, R.; Kamalov, A.; Nikitina, D.; Katsevman, E.

    2016-06-01

    A program toolset for modeling and visualization of anthropomorphic robot AR-601 produced by “NPO Androidnaya technika” was implemented, allowing one to test the components of the control system and to debug control algorithms on a virtual model of the robot. The toolset might be used for both scientific and educational purposes. The work is performed according to the Russian Government Program of Competitive Growth of the Kazan Federal University (KFU).

  10. Optimal Selection of Measurement Configurations for Stiffness Model Calibration of Anthropomorphic Manipulators

    OpenAIRE

    Klimchik, Alexandr; Wu, Yier; Pashkevich, Anatol; Caro, Stéphane; Furet, Benoît

    2012-01-01

    International audience The paper focuses on the calibration of elastostatic parameters of spatial anthropomorphic robots. It proposes a new strategy for optimal selection of the measurement configurations that essentially increases the efficiency of robot calibration. This strategy is based on the concept of the robot test-pose and ensures the best compliance error compensation for the test configuration. The advantages of the proposed approach and its suitability for practical application...

  11. Generation of human-like motion on anthropomorphic systems using inverse dynamics

    OpenAIRE

    Saab, Layale; Souères, Philippe; Mansard, Nicolas; Fourquet, Jean-Yves

    2012-01-01

    This work deals with the generation of human-like whole-body movements on anthropomorphic systems. We propose a general framework to generate robot movements from the definition of ordered stack of tasks and a global resolution scheme that enables to consider different kinds of constraints. We compare qualitatively the robot movements generated from this software with similar recorded human movements. We start with a direct global comparison of body movements. Then we analyze the magnitude of...

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

    OpenAIRE

    Kooijman, CM; Dijkstra, PU; Geertzen, JHB; Elzinga, A; Van Der Schans, CP

    2000-01-01

    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 elapsed since the amputation. The purposes of this study were to determine prevalence and factors associated with phantom pain and phantom sensations in upper limb amputees in The Netherlands. Addition...

  13. Anthropomorphic “Motion Design” on Non-Holonomic Vehicle for Intuitive Interface

    Directory of Open Access Journals (Sweden)

    Sho Yokota

    2012-11-01

    Full Text Available In the case of operating a vehicle, if the interface extracts human intention correctly and naturally, and if the vehicle moves like a human, then the human feels this operation to be intuitive. For realizing intuitive operation, this paper proposes motion design which makes vehicle motion anthropomorphic. The strategy of this motion design is: for making anthropomorphic motion, a certain normative motion for the vehicle is needed. Thus, we measure several subjectsʹ motion in order to create normative motion. But these motions are different due to individual characteristics, because human motions are described in the time domain. Therefore, the human motion in the time domain is plotted to the phase plane. In the phase plane each subjectsʹ motion was almost the same ellipse and then we fitted these ellipses to one ellipse by the least square method. Thus, we adopt this fitted ellipse as normative motion and call it “standard human motion”. The standard human motion is implemented on the actual non‐holonomic vehicle and evaluated by the Semantic Differential (SD method. From the results, we discovered that our motion design can create anthropomorphic vehicle motion.

  14. Determination of a new uniform thorax density representative of the living population from 3D external body shape modeling.

    Science.gov (United States)

    Amabile, Celia; Choisne, Julie; Nérot, Agathe; Pillet, Hélène; Skalli, Wafa

    2016-05-01

    Body segment parameters (BSP) for each body׳s segment are needed for biomechanical analysis. To provide population-specific BSP, precise estimation of body׳s segments volume and density are needed. Widely used uniform densities, provided by cadavers׳ studies, did not consider the air present in the lungs when determining the thorax density. The purpose of this study was to propose a new uniform thorax density representative of the living population from 3D external body shape modeling. Bi-planar X-ray radiographies were acquired on 58 participants allowing 3D reconstructions of the spine, rib cage and human body shape. Three methods of computing the thorax mass were compared for 48 subjects: (1) the Dempster Uniform Density Method, currently in use for BSPs calculation, using Dempster density data, (2) the Personalized Method using full-description of the thorax based on 3D reconstruction of the rib cage and spine and (3) the Improved Uniform Density Method using a uniform thorax density resulting from the Personalized Method. For 10 participants, comparison was made between the body mass obtained from a force-plate and the body mass computed with each of the three methods. The Dempster Uniform Density Method presented a mean error of 4.8% in the total body mass compared to the force-plate vs 0.2% for the Personalized Method and 0.4% for the Improved Uniform Density Method. The adjusted thorax density found from the 3D reconstruction was 0.74g/cm(3) for men and 0.73g/cm(3) for women instead of the one provided by Dempster (0.92g/cm(3)), leading to a better estimate of the thorax mass and body mass. PMID:26976227

  15. Dosimetry in an IMRT phantom designed for a remote monitoring program

    International Nuclear Information System (INIS)

    An accurate delivery of prescribed dose is essential to ensure the most successful outcome from advanced radiation treatments such as intensity modulated radiation therapy (IMRT). An anthropomorphic phantom was designed and constructed to conduct a remote-audit program for IMRT treatments. The accuracy of the dosimetry in the phantom was assessed by comparing the results obtained from different detectors with those from Monte Carlo calculations. The developed phantom has a shape of a cylinder with one target and three organs at risk (OARs) inside the unit. The target and OARs were shaped similar to those of nasopharyngeal cancer patients, and manufactured for their identification during computed tomography imaging. The phantom was designed with thermoluminescent dosimeter (TLD) holders that were inserted inside the target and the OARs for the measurements of absolute dose. In addition, the phantom allowed measurements with ionization chambers placed at the TLD locations. As a result, an inter-comparison between the two types of dosimeters was possible. For the measurement of the relative dose distribution across the target and OARs, two film slots were orthogonally placed near the center of the phantom, which also enabled the insertion of inhomogeneities near the target. Measurements with TLDs, provided by Korea Food and Drug Administration and Radiological Physics Center, and measurements with an ionization chamber (IC) were performed in four cases. The first case was one anterior field of 6 MV x rays delivered to the phantom; the second case used the same anterior field, but with inhomogeneities inserted into the phantom. The third case was three fields of 6 MV beams at an equi-gantry angle for the homogeneous phantom, and the fourth case was IMRT delivery to the phantom without inhomogeneities. For each case, measurements with both TLDs and IC were performed. For cases 1-3, theoretical predictions were obtained by using the Monte Carlo (MC) codes (BEAMnrc and

  16. Calibration of the Gamma Knife Perfexion using TG-21 and the solid water Leksell dosimetry phantom

    International Nuclear Information System (INIS)

    Purpose: To calibrate a Gamma Knife (GK) Perfexion using TG-21 with updated chamber-dependent values for modern microionization chambers in the new solid water Leksell dosimetry phantom. This work illustrates a calibration method using commercially available equipment, instruments, and an established dosimetry protocol that may be adopted at any GK center, thus reducing the interinstitutional variation in GK calibration. The calibration was verified by three third-party dosimetry checks. In addition, measurements of the relative output factors are presented and compared to available data and the new manufacturer-provided relative output factors yet to be released. Methods: An absolute dose calibration based on the TG-21 formalism, utilizing recently reported phantom material and chamber-dependent factors, was performed using a microionization chamber in a spherical solid water phantom. The result was compared to other calibration protocols based on TG-51. Independent verification of the machine output was conducted through M.D. Anderson Dosimetry Services (MDADS), using thermoluminescent dosimeters (TLDs) in an anthropomorphic head phantom; the Radiological Physics Center (RPC), using TLDs in the standard Elekta ABS plastic calibration phantom (gray phantom), included with the GK; and through a collaborative international calibration survey by the University of Pittsburgh Medical Center (UPMC) using alanine dosimeters, also in the gray phantom. The alanine dosimeters were read by the National Institute of Standards and Technology. Finally, Gafchromic EBT film was used to measure relative output factors and these factors were compared to values reported in the literature as well as new values announced for release by Elekta. The films were exposed in the solid water phantom using an included film insert accessory. Results: Compared to the TG-21 protocol in the solid water phantom, the modified and unmodified TG-51 calibrations resulted in dose rates which were 1

  17. A Thorax Simulator for Complex Dynamic Bioimpedance Measurements With Textile Electrodes.

    Science.gov (United States)

    Ulbrich, Mark; Muhlsteff, Jens; Teichmann, Daniel; Leonhardt, Steffen; Walter, Marian

    2015-06-01

    Bioimpedance measurements on the human thorax are suitable for assessment of body composition or hemodynamic parameters, such as stroke volume; they are non-invasive, easy in application and inexpensive. When targeting personal healthcare scenarios, the technology can be integrated into textiles to increase ease, comfort and coverage of measurements. Bioimpedance is generally measured using two electrodes injecting low alternating currents (0.5-10 mA) and two additional electrodes to measure the corresponding voltage drop. The impedance is measured either spectroscopically (bioimpedance spectroscopy, BIS) between 5 kHz and 1 MHz or continuously at a fixed frequency around 100 kHz (impedance cardiography, ICG). A thorax simulator is being developed for testing and calibration of bioimpedance devices and other new developments. For the first time, it is possible to mimic the complete time-variant properties of the thorax during an impedance measurement. This includes the dynamic real part and dynamic imaginary part of the impedance with a peak-to-peak value of 0.2 Ω and an adjustable base impedance (24.6 Ω ≥ Z0 ≥ 51.6 Ω). Another novelty is adjustable complex electrode-skin contact impedances for up to 8 electrodes to evaluate bioimpedance devices in combination with textile electrodes. In addition, an electrocardiographic signal is provided for cardiographic measurements which is used in ICG devices. This provides the possibility to generate physiologic impedance changes, and in combination with an ECG, all parameters of interest such as stroke volume (SV), pre-ejection period (PEP) or extracellular resistance (Re) can be simulated. The speed of all dynamic signals can be altered. The simulator was successfully tested with commercially available BIS and ICG devices and the preset signals are measured with high correlation (r = 0.996). PMID:25148671

  18. Resident lymphocytes in the epidermis and adnexal epithelia of normal dorsolateral thorax of alpacas

    OpenAIRE

    Clark, Mitzi D.; Peters-Kennedy, Jeanine; Scott, Danny W.

    2013-01-01

    A small population of resident T-lymphocytes is present in the normal epidermis of skin from humans, mice, sheep, and cattle. The objective of this study was to determine the prevalence of lymphocytes, CD3+ cells (T-lymphocytes) and CD79a+ cells (B-lymphocytes and plasma cells), in the epidermis and adnexal epithelia of alpacas. Skin-biopsy specimens from the normal skin of the dorsolateral thorax of 31 alpacas were examined histologically and immunohistochemically for the presence of CD3+ ce...

  19. Extracranial diffusion-weighted imaging. Clinical applications - abdomen, thorax, soft tissue and bone marrow Part II

    International Nuclear Information System (INIS)

    In the first part of the article the basic physical principles of DWI were considered together with sequence optimization in the extracranial applications of this imaging technic. Clinical application of DWI in general were discussed. A more detailed review of the application of DWI in focal and diffuse liver diseases was offered. This article will focus in detail on the application of DWI and the changes in DWI images in the pathological processes involving the gallbladder and bile ducts, pancreas, kidneys, adrenals, spleen, lymph nodes, large blood vessels, Gl tract, thorax, musculo-skeletal system and soft tissues. Key words: EXTRACRANIAL DIFFUSION. DWI. MRI

  20. Normal lines in the x-ray and the CT of the thorax

    International Nuclear Information System (INIS)

    The paper defines the line (band) as the longitudinal opacity not bigger than 2 mm of wide. It is a useful word, appropriately used in the description of radiological shades inside the mediastine (for example, line of previous union) or inside the lung (as the interlobars incisions). The lines of union are radiological densities formed by the interfaces of two different and independent structures that when entering in contact and depending on their position with regard to the radiation sheaf, images that can be in some cases of utility in the identification of the thorax pathology. The paper also includes the classes of lines and like they are observed in images

  1. Radiographic anatomy of the equine thorax as a basis for radiological interpretation

    International Nuclear Information System (INIS)

    This article describes the gross radiographic anatomy of the equine thorax observed on the lateral radiographic projection. The descriptions presented were derived from a retrospective study of a large number of thoracic radiographs of cases referred to the Massey University clinic in conjunction with research studies in bronchography, angiography and in vitro contrast techniques. The characteristics of the thoracic bony structures, the vasculature, and the airways are examined separately; followed by a discussion of the relative contribution of the various structures to the overall thoracic radiograph

  2. Radiation exposure of premature infants by biomedical radiography of the thorax

    International Nuclear Information System (INIS)

    Thoracic X-ray pictures of premature infants must chiefly be carried out under conditions of neonatal intensive care. For it are very often only single-pulse generators available. Radiation exposure dependends chiefly on the type of generator and comparison between single-pulse generators and 6-pulse generators was performed. CaF2 thermoluminescent dosimetry revealed that the entrance close of the useful field is considerably higher in single-pulse generators than in the 6-pulse generators. The indication for X-ray pictures of the premature infant thorax under bed-side conditions with single-pulse generators must be very precise. (author)

  3. SU-E-T-13: A Feasibility Study of the Use of Hybrid Computational Phantoms for Improved Historical Dose Reconstruction in the Study of Late Radiation Effects for Hodgkin's Lymphoma

    International Nuclear Information System (INIS)

    Purpose: Radiation-induced cancer effects are well-documented following radiotherapy. Further investigation is needed to more accurately determine a dose-response relationship for late radiation effects. Recent dosimetry studies tend to use representative patients (Taylor 2009) or anthropomorphic phantoms (Wirth 2008) for estimating organ mean doses. In this study, we compare hybrid computational phantoms to patient-specific voxel phantoms to test the accuracy of University of Florida Hybrid Phantom Library (UFHP Library) for historical dose reconstructions. Methods: A cohort of 10 patients with CT images was used to reproduce the data that was collected historically for Hodgkin's lymphoma patients (i.e. caliper measurements and photographs). Four types of phantoms were generated to show a range of refinement from reference hybrid-computational phantom to patient-specific phantoms. Each patient is matched to a reference phantom from the UFHP Library based on height and weight. The reference phantom is refined in the anterior/posterior direction to create a ‘caliper-scaled phantom’. A photograph is simulated using a surface rendering from segmented CT images. Further refinement in the lateral direction is performed using ratios from a simulated-photograph to create a ‘photograph and caliper-scaled phantom’; breast size and position is visually adjusted. Patient-specific hybrid phantoms, with matched organ volumes, are generated and show the capabilities of the UF Hybrid Phantom Library. Reference, caliper-scaled, photograph and caliper-scaled, and patient-specific hybrid phantoms are compared with patient-specific voxel phantoms to determine the accuracy of the study. Results: Progression from reference phantom to patient specific hybrid shows good agreement with the patient specific voxel phantoms. Each stage of refinement shows an overall trend of improvement in dose accuracy within the study, which suggests that computational phantoms can show

  4. SU-E-T-13: A Feasibility Study of the Use of Hybrid Computational Phantoms for Improved Historical Dose Reconstruction in the Study of Late Radiation Effects for Hodgkin's Lymphoma

    Energy Technology Data Exchange (ETDEWEB)

    Petroccia, H; O' Reilly, S; Bolch, W [J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL (United States); Mendenhall, N; Li, Z; Slopsema, R [Radiation Oncology, University of Florida Proton Therapy Institute, Jacksonville, FL (United States)

    2014-06-01

    Purpose: Radiation-induced cancer effects are well-documented following radiotherapy. Further investigation is needed to more accurately determine a dose-response relationship for late radiation effects. Recent dosimetry studies tend to use representative patients (Taylor 2009) or anthropomorphic phantoms (Wirth 2008) for estimating organ mean doses. In this study, we compare hybrid computational phantoms to patient-specific voxel phantoms to test the accuracy of University of Florida Hybrid Phantom Library (UFHP Library) for historical dose reconstructions. Methods: A cohort of 10 patients with CT images was used to reproduce the data that was collected historically for Hodgkin's lymphoma patients (i.e. caliper measurements and photographs). Four types of phantoms were generated to show a range of refinement from reference hybrid-computational phantom to patient-specific phantoms. Each patient is matched to a reference phantom from the UFHP Library based on height and weight. The reference phantom is refined in the anterior/posterior direction to create a ‘caliper-scaled phantom’. A photograph is simulated using a surface rendering from segmented CT images. Further refinement in the lateral direction is performed using ratios from a simulated-photograph to create a ‘photograph and caliper-scaled phantom’; breast size and position is visually adjusted. Patient-specific hybrid phantoms, with matched organ volumes, are generated and show the capabilities of the UF Hybrid Phantom Library. Reference, caliper-scaled, photograph and caliper-scaled, and patient-specific hybrid phantoms are compared with patient-specific voxel phantoms to determine the accuracy of the study. Results: Progression from reference phantom to patient specific hybrid shows good agreement with the patient specific voxel phantoms. Each stage of refinement shows an overall trend of improvement in dose accuracy within the study, which suggests that computational phantoms can show

  5. Quantification and comparison of visibility and image artifacts of a new liquid fiducial marker in a lung phantom for image-guided radiation therapy

    DEFF Research Database (Denmark)

    Rydhög, Jonas Scherman; Jølck, Rasmus Irming; Andresen, Thomas Lars;

    2015-01-01

    Purpose : A new biodegradable liquid fiducial marker was devised to allow for easy insertion in lung tumors using thin needles. The purpose of this study was to evaluate the visibility of the liquid fiducial markers for image-guided radiation therapy and compare to existing solid fiducial markers...... and to one existing liquid fiducial marker currently commercially available. Methods : Fiducial marker visibility was quantified in terms of contrast to noise ratio (CNR) on planar kilovoltage x-ray images in a thorax phantom for different concentrations of the radio-opaque component of the new liquid...

  6. Image Noise, CNR, and Detectability of Low-Contrast, Low-Attenuation Liver Lesions in a Phantom: Effects of Radiation Exposure, Phantom Size, Integrated Circuit Detector, and Iterative Reconstruction.

    Science.gov (United States)

    Goenka, Ajit H; Herts, Brian R; Dong, Frank; Obuchowski, Nancy A; Primak, Andrew N; Karim, Wadih; Baker, Mark E

    2016-08-01

    Purpose To assess image noise, contrast-to-noise ratio (CNR) and detectability of low-contrast, low-attenuation liver lesions in a semianthropomorphic phantom by using either a discrete circuit (DC) detector and filtered back projection (FBP) or an integrated circuit (IC) detector and iterative reconstruction (IR) with changes in radiation exposure and phantom size. Materials and Methods An anthropomorphic phantom without or with a 5-cm-thick fat-mimicking ring (widths, 30 and 40 cm) containing liver inserts with four spherical lesions was scanned with five exposure settings on each of two computed tomography scanners, one equipped with a DC detector and the other with an IC detector. Images from the DC and IC detector scanners were reconstructed with FBP and IR, respectively. Image noise and lesion CNR were measured. Four radiologists evaluated lesion presence on a five-point diagnostic confidence scale. Data analyses included receiver operating characteristic (ROC) curve analysis and noninferiority analysis. Results The combination of IC and IR significantly reduced image noise (P < .001) (with the greatest reduction in the 40-cm phantom and at lower exposures) and improved lesion CNR (P < .001). There was no significant difference in area under the ROC curve between detector-reconstruction combinations at fixed exposure for either phantom. Reader accuracy with IC-IR was noninferior at 50% (100 mAs [effective]) and 25% (300 mAs [effective]) exposure reduction for the 30- and 40-cm phantoms, respectively (adjusted P < .001 and .04 respectively). IC-IR improved readers' confidence in the presence of a lesion (P = .029) independent of phantom size or exposure level. Conclusion IC-IR improved objective image quality and lesion detection confidence but did not result in superior diagnostic accuracy when compared with DC-FBP. Moderate exposure reductions maintained comparable diagnostic accuracy for both detector-reconstruction combinations. Lesion detection in the 40

  7. Depth dose distribution study within a phantom torso after irradiation with a simulated Solar Particle Event at NSRL

    Science.gov (United States)

    Berger, Thomas; Matthiä, Daniel; Koerner, Christine; George, Kerry; Rhone, Jordan; Cucinotta, Francis A.; Reitz, Guenther

    The adequate knowledge of the radiation environment and the doses incurred during a space mission is essential for estimating an astronaut's health risk. The space radiation environment is complex and variable, and exposures inside the spacecraft and the astronaut's body are com-pounded by the interactions of the primary particles with the atoms of the structural materials and with the body itself. Astronauts' radiation exposures are measured by means of personal dosimetry, but there remains substantial uncertainty associated with the computational extrap-olation of skin dose to organ dose, which can lead to over-or under-estimation of the health risk. Comparisons of models to data showed that the astronaut's Effective dose (E) can be pre-dicted to within about a +10In the research experiment "Depth dose distribution study within a phantom torso" at the NASA Space Radiation Laboratory (NSRL) at BNL, Brookhaven, USA the large 1972 SPE spectrum was simulated using seven different proton energies from 50 up to 450 MeV. A phantom torso constructed of natural bones and realistic distributions of human tissue equivalent materials, which is comparable to the torso of the MATROSHKA phantom currently on the ISS, was equipped with a comprehensive set of thermoluminescence detectors and human cells. The detectors are applied to assess the depth dose distribution and radiation transport codes (e.g. GEANT4) are used to assess the radiation field and interactions of the radiation field with the phantom torso. Lymphocyte cells are strategically embedded at selected locations at the skin and internal organs and are processed after irradiation to assess the effects of shielding on the yield of chromosome damage. The first focus of the pre-sented experiment is to correlate biological results with physical dosimetry measurements in the phantom torso. Further on the results of the passive dosimetry using the anthropomorphic phantoms represent the best tool to generate reliable to

  8. Thorax mapping for localised lung impedance change using focused impedance measurement (FIM: A pilot study

    Directory of Open Access Journals (Sweden)

    Humayra Ferdous

    2013-12-01

    Full Text Available Focused Impedance Measurement (FIM is a technique where impedance can be measured with the optimum level of localization without much increase in complexity of measuring instrument. The electrodes are applied on the skin surface but the organs inside also contributes to the measurement, as the body is a volume conductor. In a healthy and disease free lung region, the air enters at breathe-in increases the impedance of the lung and impedance reduces during breathe-out. In contrast, for a diseased lung, where part of the lungs is filled with water or some fluid, air will not enter into this zone reducing impedance change between inspiration and expiration. With this idea, the current work had been executed to have general view of localised impedance change throughout thorax using 6-electrode FIM. This generated a matrix mapping from both the front and from the back of the thorax, which  afterwards provided that how impedance change due to ventilation varies from frontal plane to back plane of human bodies.

  9. The influence of image reconstruction algorithms on linear thorax EIT image analysis of ventilation

    International Nuclear Information System (INIS)

    Analysis methods of electrical impedance tomography (EIT) images based on different reconstruction algorithms were examined. EIT measurements were performed on eight mechanically ventilated patients with acute respiratory distress syndrome. A maneuver with step increase of airway pressure was performed. EIT raw data were reconstructed offline with (1) filtered back-projection (BP); (2) the Dräger algorithm based on linearized Newton–Raphson (DR); (3) the GREIT (Graz consensus reconstruction algorithm for EIT) reconstruction algorithm with a circular forward model (GRC) and (4) GREIT with individual thorax geometry (GRT). Individual thorax contours were automatically determined from the routine computed tomography images. Five indices were calculated on the resulting EIT images respectively: (a) the ratio between tidal and deep inflation impedance changes; (b) tidal impedance changes in the right and left lungs; (c) center of gravity; (d) the global inhomogeneity index and (e) ventilation delay at mid-dorsal regions. No significant differences were found in all examined indices among the four reconstruction algorithms (p > 0.2, Kruskal–Wallis test). The examined algorithms used for EIT image reconstruction do not influence the selected indices derived from the EIT image analysis. Indices that validated for images with one reconstruction algorithm are also valid for other reconstruction algorithms. (paper)

  10. Survey radiography and computerized tomography imaging of the thorax in female dogs with mammary tumors

    Directory of Open Access Journals (Sweden)

    Giordano Tatiana

    2010-03-01

    Full Text Available Abstract Background Accurate early diagnosis of lung metastases is important for establishing therapeutic measures. Therefore, the present study aimed to compare survey thoracic radiographs and computerized tomography (CT scans to specifically identify lung metastases in female dogs with mammary tumors. Methods Twenty-one female dogs, weighing 3 to 34 kg and aged from 5 years to 14 years and 10 months, with mammary tumors were studied. In all dogs before the imaging examinations, fine-needle aspiration cytology of the mammary tumors was performed to confirm the diagnosis. Three-view thoracic radiographs were accomplished: right lateral, left lateral and ventrodorsal views. Sequential transverse images of the thorax were acquired on a spiral Scanner, before and after intravenous bolus injection of nonionic iodine contrast. Soft-tissue and lung windows were applied. All the mammary tumors were surgically removed and examined histologically. Results The correlation between the cytological and histological results regarding presence of malignancy was observed in only 17 cases. In radiographic examinations, no dog displayed signs of lung metastases or thorax chest lesions. CT detected lung metastasis in two cases, while small areas of lung atelectasis located peripherally were found in 28.57% of the dogs. Conclusion In this study population, spiral CT showed higher sensitivity than chest radiographies to detect lung metastasis; this indicates that CT should be performed on all female dogs with malignant mammary tumors.

  11. Anthropometric approaches and their uncertainties to assigning computational phantoms to individual patients in pediatric dosimetry studies

    Energy Technology Data Exchange (ETDEWEB)

    Whalen, Scott [Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, FL 32611 (United States); Lee, Choonsik [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); Bolch, Wesley E [Departments of Nuclear and Radiological and Biomedical Engineering, University of Florida, Gainesville, FL 32611 (United States)

    2008-01-21

    Current efforts to reconstruct organ doses in children undergoing diagnostic imaging or therapeutic interventions using ionizing radiation typically rely upon the use of reference anthropomorphic computational phantoms coupled to Monte Carlo radiation transport codes. These phantoms are generally matched to individual patients based upon nearest age or sometimes total body mass. In this study, we explore alternative methods of phantom-to-patient matching with the goal of identifying those methods which yield the lowest residual errors in internal organ volumes. Various thoracic and abdominal organs were segmented and organ volumes obtained from chest-abdominal-pelvic (CAP) computed tomography (CT) image sets from 38 pediatric patients ranging in age from 2 months to 15 years. The organs segmented included the skeleton, heart, kidneys, liver, lungs and spleen. For each organ, least-squared regression lines, 95th percentile confidence intervals and 95th percentile prediction intervals were established as a function of patient age, trunk volume, estimated trunk mass, trunk height, and three estimates of the ventral body cavity volume based on trunk height alone, or in combination with circumferential, width and/or breadth measurements in the mid-chest of the patient. When matching phantom to patient based upon age, residual uncertainties in organ volumes ranged from 53% (lungs) to 33% (kidneys), and when trunk mass was used (surrogate for total body mass as we did not have images of patient head, arms or legs), these uncertainties ranged from 56% (spleen) to 32% (liver). When trunk height is used as the matching parameter, residual uncertainties in organ volumes were reduced to between 21 and 29% for all organs except the spleen (40%). In the case of the lungs and skeleton, the two-fold reduction in organ volume uncertainties was seen in moving from patient age to trunk height-a parameter easily measured in the clinic. When ventral body cavity volumes were used

  12. Anthropometric approaches and their uncertainties to assigning computational phantoms to individual patients in pediatric dosimetry studies

    International Nuclear Information System (INIS)

    Current efforts to reconstruct organ doses in children undergoing diagnostic imaging or therapeutic interventions using ionizing radiation typically rely upon the use of reference anthropomorphic computational phantoms coupled to Monte Carlo radiation transport codes. These phantoms are generally matched to individual patients based upon nearest age or sometimes total body mass. In this study, we explore alternative methods of phantom-to-patient matching with the goal of identifying those methods which yield the lowest residual errors in internal organ volumes. Various thoracic and abdominal organs were segmented and organ volumes obtained from chest-abdominal-pelvic (CAP) computed tomography (CT) image sets from 38 pediatric patients ranging in age from 2 months to 15 years. The organs segmented included the skeleton, heart, kidneys, liver, lungs and spleen. For each organ, least-squared regression lines, 95th percentile confidence intervals and 95th percentile prediction intervals were established as a function of patient age, trunk volume, estimated trunk mass, trunk height, and three estimates of the ventral body cavity volume based on trunk height alone, or in combination with circumferential, width and/or breadth measurements in the mid-chest of the patient. When matching phantom to patient based upon age, residual uncertainties in organ volumes ranged from 53% (lungs) to 33% (kidneys), and when trunk mass was used (surrogate for total body mass as we did not have images of patient head, arms or legs), these uncertainties ranged from 56% (spleen) to 32% (liver). When trunk height is used as the matching parameter, residual uncertainties in organ volumes were reduced to between 21 and 29% for all organs except the spleen (40%). In the case of the lungs and skeleton, the two-fold reduction in organ volume uncertainties was seen in moving from patient age to trunk height-a parameter easily measured in the clinic. When ventral body cavity volumes were used

  13. Anthropometric approaches and their uncertainties to assigning computational phantoms to individual patients in pediatric dosimetry studies

    Science.gov (United States)

    Whalen, Scott; Lee, Choonsik; Williams, Jonathan L.; Bolch, Wesley E.

    2008-01-01

    Current efforts to reconstruct organ doses in children undergoing diagnostic imaging or therapeutic interventions using ionizing radiation typically rely upon the use of reference anthropomorphic computational phantoms coupled to Monte Carlo radiation transport codes. These phantoms are generally matched to individual patients based upon nearest age or sometimes total body mass. In this study, we explore alternative methods of phantom-to-patient matching with the goal of identifying those methods which yield the lowest residual errors in internal organ volumes. Various thoracic and abdominal organs were segmented and organ volumes obtained from chest-abdominal-pelvic (CAP) computed tomography (CT) image sets from 38 pediatric patients ranging in age from 2 months to 15 years. The organs segmented included the skeleton, heart, kidneys, liver, lungs and spleen. For each organ, least-squared regression lines, 95th percentile confidence intervals and 95th percentile prediction intervals were established as a function of patient age, trunk volume, estimated trunk mass, trunk height, and three estimates of the ventral body cavity volume based on trunk height alone, or in combination with circumferential, width and/or breadth measurements in the mid-chest of the patient. When matching phantom to patient based upon age, residual uncertainties in organ volumes ranged from 53% (lungs) to 33% (kidneys), and when trunk mass was used (surrogate for total body mass as we did not have images of patient head, arms or legs), these uncertainties ranged from 56% (spleen) to 32% (liver). When trunk height is used as the matching parameter, residual uncertainties in organ volumes were reduced to between 21 and 29% for all organs except the spleen (40%). In the case of the lungs and skeleton, the two-fold reduction in organ volume uncertainties was seen in moving from patient age to trunk height—a parameter easily measured in the clinic. When ventral body cavity volumes were used

  14. Dental radiography: tooth enamel EPR dose assessment from Rando phantom measurements

    International Nuclear Information System (INIS)

    Electron paramagnetic resonance dosimetry of tooth enamel is now established as a suitable method for individual dose reconstruction following radiation accidents. The accuracy of the method is limited by some confounding factors, among which is the dose received due to medical x-ray irradiation. In the present paper the EPR response of tooth enamel to endoral examination was experimentally evaluated using an anthropomorphic phantom. The dose to enamel for a single exposure of a typical dental examination performed with a new x-ray generation unit working at 65 kVp gave rise to a CO2-signal of intensity similar to that induced by a dose of about 2 mGy of 60Co. EPR measurements were performed on the entire tooth with no attempt to separate buccal and lingual components. Also the dose to enamel for an orthopantomography exam was estimated. It was derived from TLD measurements as equivalent to 0.2 mGy of 60Co. In view of application to risk assessment analysis, in the present work the value for the ratio of the reference dose at the phantom surface measured with TLD to the dose at the tooth measured with EPR was determined. (author)

  15. MATSIM -The Development and Validation of a Numerical Voxel Model based on the MATROSHKA Phantom

    Science.gov (United States)

    Beck, Peter; Rollet, Sofia; Berger, Thomas; Bergmann, Robert; Hajek, Michael; Latocha, Marcin; Vana, Norbert; Zechner, Andrea; Reitz, Guenther

    The AIT Austrian Institute of Technology coordinates the project MATSIM (MATROSHKA Simulation) in collaboration with the Vienna University of Technology and the German Aerospace Center. The aim of the project is to develop a voxel-based model of the MATROSHKA anthro-pomorphic torso used at the International Space Station (ISS) as foundation to perform Monte Carlo high-energy particle transport simulations for different irradiation conditions. Funded by the Austrian Space Applications Programme (ASAP), MATSIM is a co-investigation with the European Space Agency (ESA) ELIPS project MATROSHKA, an international collaboration of more than 18 research institutes and space agencies from all over the world, under the science and project lead of the German Aerospace Center. The MATROSHKA facility is designed to determine the radiation exposure of an astronaut onboard ISS and especially during an ex-travehicular activity. The numerical model developed in the frame of MATSIM is validated by reference measurements. In this report we give on overview of the model development and compare photon and neutron irradiations of the detector-equipped phantom torso with Monte Carlo simulations using FLUKA. Exposure to Co-60 photons was realized in the standard ir-radiation laboratory at Seibersdorf, while investigations with neutrons were performed at the thermal column of the Vienna TRIGA Mark-II reactor. The phantom was loaded with passive thermoluminescence dosimeters. In addition, first results of the calculated dose distribution within the torso are presented for a simulated exposure in low-Earth orbit.

  16. Dental radiography: tooth enamel EPR dose assessment from Rando phantom measurements

    Science.gov (United States)

    Aragno, D.; Fattibene, P.; Onori, S.; Aragno, D.; Fattibene, P.

    2000-09-01

    Electron paramagnetic resonance dosimetry of tooth enamel is now established as a suitable method for individual dose reconstruction following radiation accidents. The accuracy of the method is limited by some confounding factors, among which is the dose received due to medical x-ray irradiation. In the present paper the EPR response of tooth enamel to endoral examination was experimentally evaluated using an anthropomorphic phantom. The dose to enamel for a single exposure of a typical dental examination performed with a new x-ray generation unit working at 65 kVp gave rise to a CO2- signal of intensity similar to that induced by a dose of about 2 mGy of 60Co. EPR measurements were performed on the entire tooth with no attempt to separate buccal and lingual components. Also the dose to enamel for an orthopantomography exam was estimated. It was derived from TLD measurements as equivalent to 0.2 mGy of 60Co. In view of application to risk assessment analysis, in the present work the value for the ratio of the reference dose at the phantom surface measured with TLD to the dose at the tooth measured with EPR was determined.

  17. Investigation of realistic PET simulations incorporating tumor patient's specificity using anthropomorphic models: Creation of an oncology database

    International Nuclear Information System (INIS)

    Purpose: The GATE Monte Carlo simulation toolkit is used for the implementation of realistic PET simulations incorporating tumor heterogeneous activity distributions. The reconstructed patient images include noise from the acquisition process, imaging system's performance restrictions and have limited spatial resolution. For those reasons, the measured intensity cannot be simply introduced in GATE simulations, to reproduce clinical data. Investigation of the heterogeneity distribution within tumors applying partial volume correction (PVC) algorithms was assessed. The purpose of the present study was to create a simulated oncology database based on clinical data with realistic intratumor uptake heterogeneity properties.Methods: PET/CT data of seven oncology patients were used in order to create a realistic tumor database investigating the heterogeneity activity distribution of the simulated tumors. The anthropomorphic models (NURBS based cardiac torso and Zubal phantoms) were adapted to the CT data of each patient, and the activity distribution was extracted from the respective PET data. The patient-specific models were simulated with the Monte Carlo Geant4 application for tomography emission (GATE) in three different levels for each case: (a) using homogeneous activity within the tumor, (b) using heterogeneous activity distribution in every voxel within the tumor as it was extracted from the PET image, and (c) using heterogeneous activity distribution corresponding to the clinical image following PVC. The three different types of simulated data in each case were reconstructed with two iterations and filtered with a 3D Gaussian postfilter, in order to simulate the intratumor heterogeneous uptake. Heterogeneity in all generated images was quantified using textural feature derived parameters in 3D according to the ground truth of the simulation, and compared to clinical measurements. Finally, profiles were plotted in central slices of the tumors, across lines with

  18. 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 (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 photons and neutrons

  19. Phantoms for calculations of absorbed organ dose

    International Nuclear Information System (INIS)

    We have developed a computer code IDES (Internal Dose Estimation System). In this code, MIRD Transformation Method is used and photon simulation by Monte Carlo method is also possible. We have studied Japanese phantoms in two procedures, mathematical phantom and 'symbol phantoms'. Our mathematical phantoms realize their height and body weights but does not hold some of organ weights, which were measured by TANAKA and KAWAMURA. The symbol phantom can solve this discrepancy and realize a realistic phantom, although it remains problems of authorization and normalization. Errors were estimated for internal dose calculations and it was pointed out that to use realistic organ weights and parameters of kinetics was important competitively to reduce uncertainty of the results. (author)

  20. Durable rough skin phantoms for optical modeling

    International Nuclear Information System (INIS)

    Skin phantoms are often used to study and model light propagation. However, existing skin phantoms overlook the important effect of surface roughness on light propagation patterns. This paper reports the construction of durable phantoms with controllable surface roughness and bulk optical properties. With silica microspheres as the scattering particles, we theoretically model the scatterer density required to achieve the desired phantom optical properties before fabrication. The surface roughness and the attenuation coefficients of the constructed phantoms were validated using optical profilometry and ballistic spatial filter photometry. These rough skin phantoms were originally developed for laser speckle studies, but could also be used for studying optical phenomena where light experiences surface and bulk scattering at the same time. (paper)

  1. Kerr-Like Phantom Wormhole

    OpenAIRE

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

    2013-01-01

    In this work we study a Kerr-like wormhole with phantom matter as source. It has three parameters: mass, angular momentum and scalar field charge. This wormhole has a naked ring singularity, other wise it is regular everywhere. The mean feature of this wormhole is that the mouth of the throat lie on a sphere of the same radius as the ring singularity an avoids any observer to see or to reach the singularity, it behaves like an anti-horizon. We analyse the geodesics of the wormhole and find th...

  2. 'Phantom' inflation in warped compactification

    International Nuclear Information System (INIS)

    In this paper, in a class of warped compactifications with the brane/flux annihilation, we find that the inflation may be driven by a flat direction identified as that along the number p of D3 branes located at the tip of the Klebanov-Strassler throat. The spectrum of adiabatic perturbation generated during inflation is nearly scale invariant, which may be obtained by using the results shown in the phantom inflation, since in a four-dimension effective description the evolution of energy density along the p direction is slowly increasing.

  3. Exact solution of phantom dark energy model

    Institute of Scientific and Technical Information of China (English)

    Wang Wen-Fu; Shui Zheng-Wei; Tang Bin

    2010-01-01

    We investigate the phantom dark energy model derived from the scalar field with a negative kinetic term. By assuming a particular relation between the time derivative of the phantom field and the Hubble function, an exact solution of the model is constructed. Absence of the 'big rip' singularity is shown explicitly. We then derive special features of phantom dark energy model and show that its predictions are consistent with all astrophysical observations.

  4. 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.

  5. Do Phantom Cuntz-Krieger Algebras Exist?

    DEFF Research Database (Denmark)

    Arklint, Sara E.

    2013-01-01

    If phantom Cuntz-Krieger algebras do not exist, then purely infinite Cuntz-Krieger algebras can be characterized by outer properties. In this survey paper, a summary of the known results on non-existence of phantom Cuntz-Krieger algebras is given......If phantom Cuntz-Krieger algebras do not exist, then purely infinite Cuntz-Krieger algebras can be characterized by outer properties. In this survey paper, a summary of the known results on non-existence of phantom Cuntz-Krieger algebras is given...

  6. Galileons, phantom and the Fate of Universe

    CERN Document Server

    Shahalam, M; Myrzakulov, R

    2016-01-01

    In this paper we study cosmological dynamics of phantom as well as non-phantom fields with linear potential in presence of Galileon correction $(\\partial_\\mu\\phi \\partial^\\mu\\phi) \\Box \\phi$. We show that the Big Crunch singularity is delayed compared to the standard case; the delay crucially depends upon the strength of Galileon correction. As for the phantom Galileon, $\\rho_{\\phi}$ is shown to grow more slowly compared to the standard phantom delaying the approach to singularity. In case, $V\\sim \\phi^n, n>4$, Big Rip is also delayed, similar phenomenon is shown to take place for potentials steeper than the exponential.

  7. Thermal neutron distribution in a phantom

    International Nuclear Information System (INIS)

    For the improvement of a well-approximated phantom to simulate precisely thermal neutron distribution at the actual irradiation condition in tissues or organs for the treatment of malignant tumor, neutron distribution was calculated with a Monte Carlo method for phantoms made of polyethylene, water, and Rossi solution. Dependency of thermal neutron distribution in the organism was investigated on phantom materials, irradiation area size, and boron concentration. By specifying phantom shape and size, movement and disappearance of neutron particle was simulated with injection into the phantom followed by scattering, collision or absorption. Calculation was terminated when the neutron was positioned outside the phantom. As for the distribution characteristics dependency on phantom materials, water showed similar results of distribution pattern with a Rossi solution. Polyethylene phantom needed, however, correction both for absolute value and distribution pattern. For irradiation area size, thermal neutron flux in a surface layer was reduced as the area size became smaller. As for the effect of boron concentration on the neutron flux, the effect was practically negligible in the case of not more than 10 μg 10B/g in Rossi solution. In conclusion, it was clarified that well-approximation of thermal neutron distribution by an appropriate phantom could permit dose equivalent evaluation before actual irradiation for the treatment of malignant tumor. (Takagi, S.)

  8. 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...

  9. Abdominal CT during pregnancy: a phantom study on the effect of patient centring on conceptus radiation dose and image quality

    Energy Technology Data Exchange (ETDEWEB)

    Solomou, G.; Damilakis, J. [University of Crete, Faculty of Medicine, Department of Medical Physics, Heraklion, P.O. Box 2208, Crete (Greece); Papadakis, A.E. [University Hospital of Heraklion, Department of Medical Physics, Heraklion, P.O. Box 1352, Crete (Greece)

    2015-04-01

    To investigate the effect of patient centring on conceptus radiation dose and image quality in abdominal CT during pregnancy. Three anthropomorphic phantoms that represent a pregnant woman at the three trimesters of gestation were subjected to a routine abdominal CT. Examinations were performed with fixed mAs (mAs{sub f}) and with the automatic exposure control system (AEC) activated. The percent reduction between mAs{sub f} and modulated mAs (mAs{sub mod}) was calculated. Conceptus dose (D{sub c}) was measured using thermoluminescent dosimeters. To study the effect of misplacement of pregnant women on D{sub c}, each phantom was positioned at various locations relative to gantry isocentre. Image quality was evaluated on the basis of image noise, signal-to-noise ratio, and contrast-to-noise ratio. The maximum reduction between mAs{sub f} and mAs{sub mod} was 59.8 %, while the corresponding D{sub C} reduction was 59.3 %. D{sub C} was found to decrease by up to 25 % and 7.9 % for phantom locations below and above the isocentre, respectively. Image quality deteriorated when AEC was activated, and it was progressively improved from lower to higher than the isocentre locations. Centring errors do not result in an increase in D{sub c}. To maintain image quality, accurate centring is required. (orig.)

  10. Abdominal CT during pregnancy: a phantom study on the effect of patient centring on conceptus radiation dose and image quality

    International Nuclear Information System (INIS)

    To investigate the effect of patient centring on conceptus radiation dose and image quality in abdominal CT during pregnancy. Three anthropomorphic phantoms that represent a pregnant woman at the three trimesters of gestation were subjected to a routine abdominal CT. Examinations were performed with fixed mAs (mAsf) and with the automatic exposure control system (AEC) activated. The percent reduction between mAsf and modulated mAs (mAsmod) was calculated. Conceptus dose (Dc) was measured using thermoluminescent dosimeters. To study the effect of misplacement of pregnant women on Dc, each phantom was positioned at various locations relative to gantry isocentre. Image quality was evaluated on the basis of image noise, signal-to-noise ratio, and contrast-to-noise ratio. The maximum reduction between mAsf and mAsmod was 59.8 %, while the corresponding DC reduction was 59.3 %. DC was found to decrease by up to 25 % and 7.9 % for phantom locations below and above the isocentre, respectively. Image quality deteriorated when AEC was activated, and it was progressively improved from lower to higher than the isocentre locations. Centring errors do not result in an increase in Dc. To maintain image quality, accurate centring is required. (orig.)

  11. Muscular activity when walking in a non-anthropomorphic wearable robot.

    Science.gov (United States)

    Tagliamonte, N L; Accoto, D; Sergi, F; Sudano, A; Formica, D; Guglielmelli, E

    2014-01-01

    Wearable robots should be designed not to alter human physiological motion. Perturbations introduced by a robot can be quantified by measuring EMG activity. This paper presents tests on the LENAR, an intrinsically back-drivable non-anthropomorphic lower limb wearable robot designed to provide hip and knee flexion/extension assistance. In previous works the robot was demonstrated to exhibit low mechanical impedance and to introduce minor alterations to human kinematic patterns during walking. In this paper muscular activity is assessed, demonstrating small alterations in the EMG patterns during the interaction with the robot, in both unpowered and assistive mode. PMID:25570640

  12. Modeling and control of an antagonistically actuated tendon driven anthropomorphic hand

    OpenAIRE

    Chalon, Maxime

    2013-01-01

    One of the major limitations of object manipulation with a robotic hand is the fragility of the hardware.This is one of the motivations for developing the new anthropomorphic and extremely robust Hand Arm System at the robotics and mecatronics center of DLR.The system is unique in terms of complexity, with 52 motors and more than 200 sensors, and also in terms of dynamics.Indeed, the system is mechanically compliant, thus offers the possibility to store and release energy, thereby providing t...

  13. Euclidean wormholes with Phantom field and Phantom field accompanied by perfect fluid

    OpenAIRE

    Darabi, F.

    2010-01-01

    We study the classical Euclidean wormhole solutions for the gravitational systems with minimally coupled pure Phantom field and minimally coupled Phantom field accompanied by perfect fluid. It is shown that such solutions do exist and then the general forms of the Phantom field potential are obtained for which there are classical Euclidean wormhole solutions.

  14. 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 P

  15. Extramedullary haematopoiesis as a cause of a paravertebral mass in the thorax

    International Nuclear Information System (INIS)

    The radiological due to extensive extramedullary haematopoiesis taking place in the posterior mediastinum in two patients are described, and the literature is reviewed. Characteristic features are a polycyclic or spindle-shaped configuration of the mass, with bilateral paravertebral localisation in the caudal and middle third of the thorax. There is absence of inflammatory or neoplastic changes in the neighbouring skeleton, but in thalassaemia there may be changes in the paravertebral portion of the ribs. Computer tomographically, the combination of a solid paravertebral tumour, with adjacent rib changes, is characteristic of thalassaemia with extramedullary haematopoiesis. In the absence of other skeletal changes, computed tomography is valuable for differential diagnosis. Lymphomas occur considerably more often and may appear identical but, because of the well know fat content of myolipoma, the scan shows contrast values between -15 and +40 HU. Because of their high vascularity, there is a marked increase in density following intravenous contrast medium. (orig.)

  16. Extramedullary haematopoiesis as a cause of a paravertebral mass in the thorax

    Energy Technology Data Exchange (ETDEWEB)

    Gmeinwieser, J.; Gullota, U.; Reiser, M.; Saida, Y.; Mack, D.

    1982-07-01

    The radiological symptoms due to extensive extramedullary haematopoiesis taking place in the posterior mediastinum in two patients are described, and the literature is reviewed. Characteristic features are a polycyclic or spindle-shaped configuration of the mass, with bilateral paravertebral localisation in the caudal and middle third of the thorax. There is absence of inflammatory or neoplastic changes in the neighbouring skeleton, but in thalassaemia there may be changes in the paravertebral portion of the ribs. Computer tomographically, the combination of a solid paravertebral tumour, with adjacent rib changes, is characteristic of thalassaemia with extramedullary haematopoiesis. In the absence of other skeletal changes, computed tomography is valuable for differential diagnosis. Lymphomas occur considerably more often and may appear identical but, because of the well know fat content of myolipoma, the scan shows contrast values between -15 and +40 HU. Because of their high vascularity, there is a marked increase in density following intravenous contrast medium.

  17. In vivo 3D FD OCT of subpleural lung parenchyma in the intact thorax

    Science.gov (United States)

    Meissner, S.; Schnabel, C.; Knels, L.; Koch, E.

    2010-02-01

    In vivo determination of three-dimensional and dynamic geometries of alveolar structures with adequate resolution is essential to develop numerical models of the lung. To gain insight into the dynamics of alveoli a thorax window was prepared in anesthetized rabbits by removal of muscle tissue between 3rd and 4th rib without harming the parietal pleura. The transparent parietal pleura allows contact-free imaging by intra-vital microscopy (IVM) and 3D optical coherence tomography (3D-OCT). We have demonstrated that it is possible to acquire the identical region in the inspiratory and expiratory phase, and that OCT in this animal model is suitable for generating 3D geometry of in vivo lung parenchyma. The 3D data sets of the fine structure of the lung beneath the pleura could provide a basis for the development of threedimensional numerical models of the lung.

  18. Malignant diffuse pleural mesothelioma: Comparison between computed tomography and conventional plain radiography of the thorax

    International Nuclear Information System (INIS)

    The rate of incidence of malignant pleural mesothelioma is increasing although diagnosis of this disease may be very difficult. Computed tomography examinations and conventional chest X-rays of 30 patients with malignant pleural mesothelioma were reviewed independently, to evaluate the role of both modalities. CT offered the following advantages over conventional chest X-ray examinations: Ct was more sensitive in detecting the smooth and nodular changes of malignant pleural mesothelioma, especially at the diaphragm and lower parts of the thorax, tumours could be better demonstrated at the pericardium and in the greater fissure, in some cases, where chest films showed just abnormal widening of the mediastinum, CT could differentiate between tumour involvement of the mediastinal pleura and local invasion of the mediastinum by the tumour CT was more effective in detecting pleural calcifications and thickening of the contralateral pleura. CT proves more accurate in assessing the extent of the disease, and gives additional diagnostic help. (orig.)

  19. The thorax morphology of Epiophlebia (Insecta: Odonata) nymphs--including remarks on ontogenesis and evolution.

    Science.gov (United States)

    Büsse, Sebastian; Helmker, Benjamin; Hörnschemeyer, Thomas

    2015-01-01

    The species of Epiophlebia are unique among the recent Odonata in showing a mixture of morphological characters of dragonflies (Anisoptera) and damselflies (Zygoptera). The status of the four described extant species of Epiophlebia is disputable from a genetic as well as from a morphological point of view. Here we present an analysis of the thoracic musculature of different nymphal instars of Epiophlebia laidlawi and Epiophlebia superstes to elucidate their morphology and ontogenetic development. In total, 75 muscles have been identified in the thorax of Epiophlebia. This represents the highest number of thoracic muscles ever found in any odonate. It includes six muscles that are reported for the first time for Odonata, and three of these are even new for Pterygota. In total, our results indicate that Epiophlebia has the most ancestral thoracic morphology among Odonata. PMID:26246088

  20. A phantom model demonstration of tomotherapy dose painting delivery, including managed respiratory motion without motion management

    Energy Technology Data Exchange (ETDEWEB)

    Kissick, Michael W; Mo Xiaohu; McCall, Keisha C; Mackie, Thomas R [Department of Medical Physics, Wisconsin Institutes for Medical Research, 111 Highland Avenue, University of Wisconsin-Madison, Madison, WI 53705 (United States); Schubert, Leah K [Radiation Oncology Department, University of Nebraska Medical Center, Omaha, NE 68198 (United States); Westerly, David C, E-mail: mwkissick@wisc.ed [Department of Radiation Oncology, University of Colorado Denver, Aurora, CO 80045 (United States)

    2010-05-21

    The aim of the study was to demonstrate a potential alternative scenario for accurate dose-painting (non-homogeneous planned dose) delivery at 1 cm beam width with helical tomotherapy (HT) in the presence of 1 cm, three-dimensional, intra-fraction respiratory motion, but without any active motion management. A model dose-painting experiment was planned and delivered to the average position (proper phase of a 4DCT scan) with three spherical PTV levels to approximate dose painting to compensate for hypothetical hypoxia in a model lung tumor. Realistic but regular motion was produced with the Washington University 4D Motion Phantom. A small spherical Virtual Water(TM) phantom was used to simulate a moving lung tumor inside of the LUNGMAN(TM) anthropomorphic chest phantom to simulate realistic heterogeneity uncertainties. A piece of 4 cm Gafchromic EBT(TM) film was inserted into the 6 cm diameter sphere. TomoTherapy, Inc., DQA(TM) software was used to verify the delivery performed on a TomoTherapy Hi-Art II(TM) device. The dose uncertainty in the purposeful absence of motion management and in the absence of large, low frequency drifts (periods greater than the beam width divided by the couch velocity) or randomness in the breathing displacement yields very favorable results. Instead of interference effects, only small blurring is observed because of the averaging of many breathing cycles and beamlets and the avoidance of interference. Dose painting during respiration with helical tomotherapy is feasible in certain situations without motion management. A simple recommendation is to make respiration as regular as possible without low frequency drifting. The blurring is just small enough to suggest that it may be acceptable to deliver without motion management if the motion is equal to the beam width or smaller (at respiration frequencies) when registered to the average position.

  1. Liver hydatid cyst ruptured into the thorax: CT angiography findings of a case

    International Nuclear Information System (INIS)

    Full text: Introduction: Intrathoracic rupture of hepatic hydatid cyst is a rare but severe condition causing a spectrum of lesions to the pleura, lung parenchyma, and bronchi. Pulmonary complications result from the proximity of hydatid cysts in the liver and the diaphragm. Objectives and tasks: In this report we aimed to present computed tomography (CT) angiography findings of a case with liver hydatid cyst ruptured into the thorax. The patient underwent CT angiography examination with suspicion of pulmonary embolism. Materials and methods: A 71-year-old female patient admitted to our emergency department with complaints of severe and persistent cough. Basal region of the right hemithorax could not get breath sounds on physical examination. Chest radiography revealed the presence of consolidation-effusion. The patient was treated with antibiotherapy for pneumonia and parapneumonic effusion. Because of the clinical symptoms and chest radiograph findings persisted the patient underwent CT angiography examination with suspicion of pulmonary embolism. Results: On CT angiography images pulmonary artery and its branches were normal. There were subtotal collapse in the right middle and lower lung lobes and complicated cystic lesion that has air densities in the basal interlobar space. Another thick walled complicated cystic lesion with multiple septations and air densities was detected in the right posterior liver lobe. The right hemidiaphragm was interrupted and the right liver lobe partially herniated into the thorax cavity. Serologic tests were positive for Echinococcus granulosus and there were prior therapy history for liver cyst hydatid. The diagnostic aspiration findings were consistent with hydatid cyst lesion. Conclusion: In patients with hepatic hydatid cyst associated with persistent and severe cough, thoracic rupture of the cyst should be considered in differential diagnosis. CT angiography is fast, non-invasive and effective method in the detection of

  2. Anthropomorphic measurements

    International Nuclear Information System (INIS)

    Based on decisions taken during the Research Coordination Meetings in Mito City 1988 and Bombay 1991, the participants were requested to provide data on physical measurement parameters of body height, body weight, sitting height, head circumference, neck circumference, chest circumference, chest width and chest depth which represented the age groups as newborn, 1 year, 5 years, 10 years, 15 years and adult 20-50 years. Accordingly, physical measurement data was obtained by participants from 9 countries

  3. Calculation of organ doses from environmental gamma rays using human phantoms and Monte Carlo methods. Pt. 1

    International Nuclear Information System (INIS)

    Organ doses from environmental γ-rays (U-238, Th-232, K-40) were calculated using Monte Carlo methods for three typical sources of a semi-infinite volume source in the air, an infinite plane source in the ground and a volume source in the ground. γ-ray fields in the natural environment were simulated rigourously without approximations or simplifications in the intermediate steps except for the disturbance of the radiation field by the human body which was neglected. Organ doses were calculated for four anthropomorphic phantoms representing a baby, a child, a female and a male adult. The dose of a fetus is given by the dose to the uterus of the adult female. Air kerma and dose conversion factors normalised to air kerma and to source intensity are given for monoenergetic sources and for the natural radionuclides. (orig./HP)

  4. Development of phantom and methodology for 3D and 4D dose intercomparisons for advanced lung radiotherapy

    International Nuclear Information System (INIS)

    There are few reported intercomparisons or audits of combinations of advanced radiotherapy methods, particularly for 4D treatments. As part of an evaluation of the implementation of advanced radiotherapy technology, a phantom and associated methods, initially developed for in-house commissioning and QA of 4D lung treatments, has been developed further with the aim of using it for end-to-end dose intercomparison of 4D treatment planning and delivery. The respiratory thorax phantom can house moving inserts with variable speed (breathing rate) and motion amplitude. In one set-up mode it contains a small ion chamber for point dose measurements, or alternatively it can hold strips of radiochromic film to measure dose distributions. Initial pilot and feasibility measurements have been carried out in one hospital to thoroughly test the methods and procedures before using it more widely across a range of hospitals and treatment systems. Overall, the results show good agreement between measured and calculated doses and distributions, supporting the use of the phantom and methodology for multi-centre intercomparisons. However, before wider use, refinements of the method and analysis are currently underway particularly for the film measurements

  5. An overview of systems for CT- and MRI-guided percutaneous needle placement in the thorax and abdomen

    NARCIS (Netherlands)

    Arnolli, Maarten M.; Hanumara, Nevan C.; Franken, Michel; Brouwer, Dannis M.; Broeders, Ivo A.M.J.

    2014-01-01

    Minimally invasive biopsies, drainages and therapies in the soft tissue organs of the thorax and abdomen are typically performed through a needle, which is inserted percutaneously to reach the target area. The conventional workflow for needle placement employs an iterative freehand technique. This a

  6. Evaluation of central catheters and endotracheal tubes in the unit of intensive care with x-ray of portable thorax

    International Nuclear Information System (INIS)

    We carried out a revision of the parameters that define the connect location of the different types of central catheters and endotracheal tube in patients hospitalized at the intensive care unit; by means of the evaluation with portable X-ray of the thorax, describing the complications associated to this vital support

  7. Fundamental theories in a phantom universe

    OpenAIRE

    Gonzalez-Diaz, Pedro F.

    2004-01-01

    Starting with the holographic dark energy model of Li it is shown that the holographic screen at the future event horizon is sent toward infinity in the phantom energy case, so allowing for the existence of unique fundamental theories which are mathematically consistent in phantom cosmologies.

  8. 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. PMID:23608362

  9. Phantom Field and the Fate of Universe

    OpenAIRE

    Sami, M.; Toporensky, Alexey

    2003-01-01

    In this paper we analyze the cosmological dynamics of phantom field in a variety of potentials unbounded from above. We demonstrate that the nature of future evolution generically depends upon the steepness of the phantom potential and discuss the fate of Universe accordingly.

  10. Gravitational Wave Background from Phantom Superinflation

    OpenAIRE

    Piao, Yun-Song

    2006-01-01

    Recently, the early superinflation driven by phantom field has been proposed and studied. The detection of primordial gravitational wave is an important means to know the state of very early universe. In this brief report we discuss in detail the gravitational wave background excited during the phantom superinflation.

  11. Do phantom Cuntz-Krieger algebras exist?

    OpenAIRE

    Arklint, Sara

    2012-01-01

    If phantom Cuntz-Krieger algebras do not exist, then real rank zero Cuntz-Krieger algebras can be characterized by outer properties. In this survey paper, a summary of the known results on non-existence of phantom Cuntz-Krieger algebras is given.

  12. Phantom Wormholes in (2+1)-dimensions

    OpenAIRE

    Jamil, Mubasher; Farooq, M. Umar

    2010-01-01

    In this paper, we have constructed a (2+1)-dimensional wormhole using inhomogeneous and anisotropic distribution of phantom energy. We have determined the exact form of the equation of state of phantom energy that supports the wormhole structure. Interestingly, this equation of state is linear but variable one and is dependent only on the radial parameter of the model.

  13. Oscillating phantom in $F(R)$ gravity

    OpenAIRE

    Bamba, Kazuharu; Geng, Chao-Qiang

    2009-01-01

    We investigate the oscillating effective equation of state (EoS) of the universe around the phantom divide in the framework of $F(R)$ gravity. We illustrate the behavior of $F(R)$ with realizing multiple crossings of the phantom divide.

  14. In good company? Perception of movement synchrony of a non-anthropomorphic robot.

    Science.gov (United States)

    Lehmann, Hagen; Saez-Pons, Joan; Syrdal, Dag Sverre; Dautenhahn, Kerstin

    2015-01-01

    Recent technological developments like cheap sensors and the decreasing costs of computational power have brought the possibility of robotic home companions within reach. In order to be accepted it is vital for these robots to be able to participate meaningfully in social interactions with their users and to make them feel comfortable during these interactions. In this study we investigated how people respond to a situation where a companion robot is watching its user. Specifically, we tested the effect of robotic behaviours that are synchronised with the actions of a human. We evaluated the effects of these behaviours on the robot's likeability and perceived intelligence using an online video survey. The robot used was Care-O-bot3, a non-anthropomorphic robot with a limited range of expressive motions. We found that even minimal, positively synchronised movements during an object-oriented task were interpreted by participants as engagement and created a positive disposition towards the robot. However, even negatively synchronised movements of the robot led to more positive perceptions of the robot, as compared to a robot that does not move at all. The results emphasise a) the powerful role that robot movements in general can have on participants' perception of the robot, and b) that synchronisation of body movements can be a powerful means to enhance the positive attitude towards a non-anthropomorphic robot. PMID:26001025

  15. In good company? Perception of movement synchrony of a non-anthropomorphic robot.

    Directory of Open Access Journals (Sweden)

    Hagen Lehmann

    Full Text Available Recent technological developments like cheap sensors and the decreasing costs of computational power have brought the possibility of robotic home companions within reach. In order to be accepted it is vital for these robots to be able to participate meaningfully in social interactions with their users and to make them feel comfortable during these interactions. In this study we investigated how people respond to a situation where a companion robot is watching its user. Specifically, we tested the effect of robotic behaviours that are synchronised with the actions of a human. We evaluated the effects of these behaviours on the robot's likeability and perceived intelligence using an online video survey. The robot used was Care-O-bot3, a non-anthropomorphic robot with a limited range of expressive motions. We found that even minimal, positively synchronised movements during an object-oriented task were interpreted by participants as engagement and created a positive disposition towards the robot. However, even negatively synchronised movements of the robot led to more positive perceptions of the robot, as compared to a robot that does not move at all. The results emphasise a the powerful role that robot movements in general can have on participants' perception of the robot, and b that synchronisation of body movements can be a powerful means to enhance the positive attitude towards a non-anthropomorphic robot.

  16. The anthropomorphic design and experiments of HIT/DLR five-fingered dexterous hand

    Institute of Scientific and Technical Information of China (English)

    Fan Shaowei; Liu Yiwei; Jin Minghe; Lan Tian; Liu Hong

    2009-01-01

    This paper presents a new developed anthropomorphic robot dexterous hand: HIT/DLR Hand II. The hand is composed of an independent palm and five identical modular fingers, and each finger has three degree of freedom (DOFs) and four joints. All the actuators and electronics are integrated in the finger body and the palm. Owing to using a new actuator, drivers and a novel arrangement, both the length and width of the finger is about two third of its former version. By using the wire coupling mechanism, the distal phalanx transmission ratio is kept exactly 1:1 in the whole movement range. The packing mechanism which is implemented directly in the finger body and palm not only reduces the size of whole hand but also make it more anthropomorphic. Additionally, the new designed force/torque and position sensors are integrated in the hand for increasing multisensory capability. To evaluate the performances of the finger mechanism, the position and impedance control experiments are conducted.

  17. Effect of trunk sagittal attitude on shoulder, thorax and pelvis three-dimensional kinematics in able-bodied subjects during gait.

    Directory of Open Access Journals (Sweden)

    Alberto Leardini

    Full Text Available It has been shown that an original attitude in forward or backward inclination of the trunk is maintained at gait initiation and during locomotion, and that this affects lower limb loading patterns. However, no studies have shown the extent to which shoulder, thorax and pelvis three-dimensional kinematics are modified during gait due to this sagittal inclination attitude. Thirty young healthy volunteers were analyzed during level walking with video-based motion analysis. Reflecting markers were mounted on anatomical landmarks to form a two-marker shoulder line segment, and a four-marker thorax and pelvis segments. Absolute and relative spatial rotations were calculated, for a total of 11 degrees of freedom. The subjects were divided into two groups of 15 according to the median of mean thorax inclination angle over the gait cycle. Preliminary MANOVA analysis assessed whether gender was an independent variable. Then two-factor nested ANOVA was used to test the possible effect of thorax inclination on body segments, planes of motion and gait periods, separately. There was no significant difference in all anthropometric and spatio-temporal parameters between the two groups, except for subject mass. The three-dimensional kinematics of the thorax and pelvis were not affected by gender. Nested ANOVA revealed group effect in all segment rotations apart those at the pelvis, in the sagittal and frontal planes, and at the push-off. Attitudes in sagittal thorax inclination altered trunk segments kinematics during gait. Subjects with a backward thorax showed less thorax-to-pelvis motion, but more shoulder-to-thorax and thorax-to-laboratory motion, less motion in flexion/extension and in lateral bending, and also less motion during push-off. This contributes to the understanding of forward propulsion and sideways load transfer mechanisms, fundamental for the maintenance of balance and the risk of falling.

  18. LAXS investigation of finger phantoms

    International Nuclear Information System (INIS)

    Osteoporosis is a bone condition that is caused mainly by the degradation of trabecular and cortical bone resulting in the decrease of bone strength and eventually leads to bone fracture. A low angle X-ray scattering (LAXS) system that uses mainly the coherent scattering process for the characterisation of materials was constructed to study such bone conditions. Several finger phantoms were fabricated to simulate bone of varying densities. The LAXS method was able to identify the changes in bone density quite well by comparing energy dispersive X-ray diffraction patterns as well as the angular patterns. Quantitative information can be extracted from such patterns that relate to bone loss. Signature patterns at low exposure times were produced in order to reduce the dose received with reasonable identification power but at slightly higher statistical errors compared with long exposure patterns. Use of other parameters to increase the sensitivity was attempted

  19. Galactosemia and phantom absence seizures

    Directory of Open Access Journals (Sweden)

    Zeynep Aydin-Özemir

    2014-01-01

    Full Text Available Generalized and focal seizures can rarely be seen in galactosemia patients, but absence seizures were not reported previously. An 18-year-old male was diagnosed as galactosemia at the age of 8 months. No family history of epilepsy was present. His absence seizures realized at the age of 9 years. Generalized 3-4 Hz spike-wave discharges were identified in his electroencephalography. Homozygous mutation at exon 6 c. 563A > G was identified. The electroencephalogram of his sibling was unremarkable. Our aim was to present the long-term follow-up of a patient diagnosed with galactosemia, who had phantom absence seizures and typical 3-4 Hz spike-wave discharges in his electroencephalogram to draw attention to this rare association.

  20. Galactosemia and phantom absence seizures.

    Science.gov (United States)

    Aydin-Özemir, Zeynep; Tektürk, Pınar; Uyguner, Zehra Oya; Baykan, Betül

    2014-01-01

    Generalized and focal seizures can rarely be seen in galactosemia patients, but absence seizures were not reported previously. An 18-year-old male was diagnosed as galactosemia at the age of 8 months. No family history of epilepsy was present. His absence seizures realized at the age of 9 years. Generalized 3-4 Hz spike-wave discharges were identified in his electroencephalography. Homozygous mutation at exon 6 c. 563A > G was identified. The electroencephalogram of his sibling was unremarkable. Our aim was to present the long-term follow-up of a patient diagnosed with galactosemia, who had phantom absence seizures and typical 3-4 Hz spike-wave discharges in his electroencephalogram to draw attention to this rare association. PMID:25624930