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Sample records for anthropomorphic thorax phantom

  1. Design, development, and implementation of the Radiological Physics Center's pelvis and thorax anthropomorphic quality assurance phantoms

    International Nuclear Information System (INIS)

    Followill, David S.; Radford Evans, DeeAnn; Cherry, Christopher; Molineu, Andrea; Fisher, Gary; Hanson, William F.; Ibbott, Geoffrey S.

    2007-01-01

    The Radiological Physics Center (RPC) developed two heterogeneous anthropomorphic quality assurance phantoms for use in verifying the accuracy of radiation delivery: one for intensity-modulated radiation therapy (IMRT) to the pelvis and the other for stereotactic body radiation therapy (SBRT) to the thorax. The purpose of this study was to describe the design and development of these two phantoms and to demonstrate the reproducibility of measurements generated with them. The phantoms were built to simulate actual patient anatomy. They are lightweight and water-fillable, and they contain imageable targets and organs at risk of radiation exposure that are of similar densities to their human counterparts. Dosimetry inserts accommodate radiochromic film for relative dosimetry and thermoluminesent dosimetry capsules for absolute dosimetry. As a part of the commissioning process, each phantom was imaged, treatment plans were developed, and radiation was delivered at least three times. Under these controlled irradiation conditions, the reproducibility of dose delivery to the target TLD in the pelvis and thorax phantoms was 3% and 0.5%, respectively. The reproducibility of radiation-field localization was less than 2.5 mm for both phantoms. Using these anthropomorphic phantoms, pelvic IMRT and thoracic SBRT radiation treatments can be verified with a high level of precision. These phantoms can be used to effectively credential institutions for participation in specific NCI-sponsored clinical trials

  2. Anthropomorphic thorax phantom for cardio-respiratory motion simulation in tomographic imaging

    Science.gov (United States)

    Bolwin, Konstantin; Czekalla, Björn; Frohwein, Lynn J.; Büther, Florian; Schäfers, Klaus P.

    2018-02-01

    Patient motion during medical imaging using techniques such as computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), or single emission computed tomography (SPECT) is well known to degrade images, leading to blurring effects or severe artifacts. Motion correction methods try to overcome these degrading effects. However, they need to be validated under realistic conditions. In this work, a sophisticated anthropomorphic thorax phantom is presented that combines several aspects of a simulator for cardio-respiratory motion. The phantom allows us to simulate various types of cardio-respiratory motions inside a human-like thorax, including features such as inflatable lungs, beating left ventricular myocardium, respiration-induced motion of the left ventricle, moving lung lesions, and moving coronary artery plaques. The phantom is constructed to be MR-compatible. This means that we can not only perform studies in PET, SPECT and CT, but also inside an MRI system. The technical features of the anthropomorphic thorax phantom Wilhelm are presented with regard to simulating motion effects in hybrid emission tomography and radiotherapy. This is supplemented by a study on the detectability of small coronary plaque lesions in PET/CT under the influence of cardio-respiratory motion, and a study on the accuracy of left ventricular blood volumes.

  3. Using 3D printing techniques to create an anthropomorphic thorax phantom for medical imaging purposes.

    Science.gov (United States)

    Hazelaar, Colien; van Eijnatten, Maureen; Dahele, Max; Wolff, Jan; Forouzanfar, Tymour; Slotman, Ben; Verbakel, Wilko F A R

    2018-01-01

    Imaging phantoms are widely used for testing and optimization of imaging devices without the need to expose humans to irradiation. However, commercially available phantoms are commonly manufactured in simple, generic forms and sizes and therefore do not resemble the clinical situation for many patients. Using 3D printing techniques, we created a life-size phantom based on a clinical CT scan of the thorax from a patient with lung cancer. It was assembled from bony structures printed in gypsum, lung structures consisting of airways, blood vessels >1 mm, and outer lung surface, three lung tumors printed in nylon, and soft tissues represented by silicone (poured into a 3D-printed mold). Kilovoltage x-ray and CT images of the phantom closely resemble those of the real patient in terms of size, shapes, and structures. Surface comparison using 3D models obtained from the phantom and the 3D models used for printing showed mean differences phantom show that the phantom is able to endure radiation doses over 24,000 Gy. It is feasible to create an anthropomorphic thorax phantom using 3D printing and molding techniques. The phantom closely resembles a real patient in terms of spatial accuracy and is currently being used to evaluate x-ray-based imaging quality and positional verification techniques for radiotherapy. © 2017 American Association of Physicists in Medicine.

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

    OpenAIRE

    Yoo, Wook Jae; Shin, Sang Hun; Jeon, Dayeong; Hong, Seunghan; Sim, Hyeok In; Kim, Seon Geun; Jang, Kyoung Won; Cho, Seunghyun; Youn, Won Sik; Lee, Bongsoo

    2014-01-01

    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 obt...

  5. Design of a multimodal ({sup 1}H/{sup 23}Na MR/CT) anthropomorphic thorax phantom

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, Wiebke; Lietzmann, Florian; Schad, Lothar R.; Zoellner, Frank G. [Heidelberg Univ., Mannheim (Germany). Computer Assisted Clinical Medicine

    2017-08-01

    This work proposes a modular, anthropomorphic MR and CT thorax phantom that enables the comparison of experimental studies for quantitative evaluation of deformable, multimodal image registration algorithms and realistic multi-nuclear MR imaging techniques. A human thorax phantom was developed with insertable modules representing lung, liver, ribs and additional tracking spheres. The quality of human tissue mimicking characteristics was evaluated for {sup 1}H and {sup 23}Na MR as well as CT imaging. The position of landmarks in the lung lobes was tracked during CT image acquisition at several positions during breathing cycles. {sup 1}H MR measurements of the liver were repeated after seven months to determine long term stability. The modules possess HU, T{sub 1} and T{sub 2} values comparable to human tissues (lung module: -756 ± 148 HU, artificial ribs: 218 ± 56 HU (low CaCO{sub 3} concentration) and 339 ± 121 (high CaCO{sub 3} concentration), liver module: T{sub 1} = 790 ± 28 ms, T{sub 2} = 65 ± 1 ms). Motion analysis showed that the landmarks in the lung lobes follow a 3D trajectory similar to human breathing motion. The tracking spheres are well detectable in both CT and MRI. The parameters of the tracking spheres can be adjusted in the following ranges to result in a distinct signal: HU values from 150 to 900 HU, T{sub 1} relaxation time from 550 ms to 2000 ms, T{sub 2} relaxation time from 40 ms to 200 ms. The presented anthropomorphic multimodal thorax phantom fulfills the demands of a simple, inexpensive system with interchangeable components. In future, the modular design allows for complementing the present set up with additional modules focusing on specific research targets such as perfusion studies, {sup 23}Na MR quantification experiments and an increasing level of complexity for motion studies.

  6. 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.

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

    International Nuclear Information System (INIS)

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

    2016-01-01

    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. - Highlights: • Using TLD-100 dosimeters and a RANDO phantom 5 CT thorax protocol organ doses were assessed. • The specific k coefficient for effective dose estimation of protocols differed with approach. • Organ dose was observed to decrease in the order: thyroid>skin>lung>liver>breast. • E103 k factors were constant for all protocols, lower by ~8% compared to the universal k factor.

  8. Measurement of entrance surface dose on an anthropomorphic thorax phantom using a miniature fiber-optic dosimeter.

    Science.gov (United States)

    Yoo, Wook Jae; Shin, Sang Hun; Jeon, Dayeong; Hong, Seunghan; Sim, Hyeok In; Kim, Seon Geun; Jang, Kyoung Won; Cho, Seunghyun; Youn, Won Sik; Lee, Bongsoo

    2014-04-01

    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.

  9. 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.

  10. 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

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, J. D., E-mail: j.d.thompson@salford.ac.uk [Directorate of Radiography, University of Salford, Frederick Road Campus, Salford, Greater Manchester M6 6PU, United Kingdom and Department of Radiology, Furness General Hospital, University Hospitals of Morecambe Bay NHS Foundation Trust, Dalton Lane, Barrow-in-Furness LA14 4LF (United Kingdom); Chakraborty, D. P. [Department of Radiology, University of Pittsburgh, FARP Building, Room 212, 3362 Fifth Avenue, Pittsburgh, Pennsylvania 15213 (United States); Szczepura, K.; Tootell, A. K. [Directorate of Radiography, University of Salford, Frederick Road Campus, Salford, Greater Manchester M6 6PU (United Kingdom); Vamvakas, I. [Department of Radiology, Christie Hospitals NHS Foundation Trust, 550 Wilmslow Road, Manchester M20 4BX (United Kingdom); Manning, D. J. [Faculty of Health and Medicine, Lancaster Medical School, Furness College, Lancaster University, Lancaster LA1 4YG (United Kingdom); Hogg, P. [Directorate of Radiography, University of Salford, Frederick Road Campus, Salford, Greater Manchester M6 6PU, United Kingdom and Department of Radiography, Karolinksa Institute, Solnavägen 1, Solna 171 77 (Sweden)

    2016-03-15

    Purpose: To evaluate nodule detection in an anthropomorphic chest phantom in computed tomography (CT) images reconstructed with adaptive iterative dose reduction 3D (AIDR{sup 3D}) 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 generate CT images for the observer study; (ii) a whole-body dosimetry verification phantom was used to ultimately estimate effective dose and risk according to the model of the BEIR VII committee. Both phantoms were scanned over a mAs range (10, 20, 30, and 40), while all other acquisition parameters remained constant. Images were reconstructed with both AIDR{sup 3D} and FBP. For the observer study, 34 normal cases (no nodules) and 34 abnormal cases (containing 1–3 nodules, mean 1.35 ± 0.54) were chosen. Eleven observers evaluated images from all mAs and reconstruction methods under the free-response paradigm. A crossed-modality jackknife alternative free-response operating characteristic (JAFROC) analysis method was developed for data analysis, averaging data over the two factors influencing nodule detection in this study: mAs and image reconstruction (AIDR{sup 3D} or FBP). A Bonferroni correction was applied and the threshold for declaring significance was set at 0.025 to maintain the overall probability of Type I error at α = 0.05. Contrast-to-noise (CNR) was also measured for all nodules and evaluated by a linear least squares analysis. Results: For random-reader fixed-case crossed-modality JAFROC analysis, there was no significant difference in nodule detection between AIDR{sup 3D} and FBP when data were averaged over mAs [F(1, 10) = 0.08, p = 0.789]. However, when data were averaged over reconstruction methods, a significant difference was seen between

  11. 21 CFR 892.1370 - Nuclear anthropomorphic phantom.

    Science.gov (United States)

    2010-04-01

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

  12. 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... phantom. (a) Identification. A radiographic anthropomorphic phantom is a device intended for medical...

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

    International Nuclear Information System (INIS)

    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.

    2014-01-01

    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 (K i ) 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. - Highlights: ► An anthropomorphic chest phantom was to characterise for dosimetric measurements. ► Anthropomorphic phantom developed for image quality can also be used for dosimetry. ► BSFs were compared and showed tendencies found in the literature. ► CCs equivalent and effective doses obtained for the phantom are within the expected

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

    International Nuclear Information System (INIS)

    Cerqueira, R.A.D.; Maia, A.F.

    2014-01-01

    The objective of this study was to develop thyroid anthropomorphic phantoms to be used in control tests of medical images in scintillation cameras. The main difference among the phantoms was the neck shape: in the first, called OSCT, it was geometrically shaped, while in the second, called OSAP, it was anthropomorphically shaped. In both phantoms, thyroid gland prototypes, which were made of acrylic and anthropomorphically shaped, were constructed to allow the simulation of a healthy thyroid and of thyroids with hyperthyroidism and hypothyroidism. Images of these thyroid anthropomorphic phantoms were obtained using iodine 131 with an activity of 8.695 MBq. The iodine 131 was chosen because it is widely used in studies of thyroid scintigraphy. The images obtained proved the effectiveness of the phantoms to simulate normal or abnormal thyroids function. These phantoms can be used in medical imaging quality control programs and, also in the training of professionals involved in the analysis of images in nuclear medicine centers. - 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

  15. 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.

  16. Development of a physical 3D anthropomorphic breast phantom

    International Nuclear Information System (INIS)

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

    2011-01-01

    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.

  17. Effective dose measurement at workplaces within an instrumented anthropomorphic phantom

    International Nuclear Information System (INIS)

    Villagrasa, C.; Darreon, J.; Martin-Burtat, N.; Clairand, I.; Colin, J.; Fontbonne, J. M.

    2011-01-01

    The Laboratory of Ionizing Radiation Dosimetry of the IRSN (France) is developing an instrumented anthropomorphic phantom in order to measure the effective dose for photon fields at workplaces. This anthropomorphic phantom will be equipped with small active detectors located inside at chosen positions. The aim of this paper is to present the development of these new detectors showing the results of the characterisation of the prototype under metrological conditions. New evaluations of the effective dose for standard and non-homogenous irradiation configurations taking into account the real constraints of the project have been done validating the feasibility and utility of the instrument. (authors)

  18. 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

  19. 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

  20. 3D printer generated thorax phantom with mobile tumor for radiation dosimetry

    International Nuclear Information System (INIS)

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

    2015-01-01

    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

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

    International Nuclear Information System (INIS)

    Hintenlang, David E.

    2009-01-01

    The overall objective of this project was the development of a dosimetry system that provides the direct measurement of organ doses 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

  2. Optimized generation of high resolution breast anthropomorphic software phantoms

    Science.gov (United States)

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

    2012-01-01

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

  3. 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.

  4. Validation study of the thorax phantom Lungman for optimization purposes

    Science.gov (United States)

    Rodríguez Pérez, Sunay; Marshall, Nicholas W.; Struelens, Lara; Bosmans, Hilde

    2017-03-01

    This work aims to investigate the advantages and limitations of the Kyoto Kagaku thorax phantom Lungman for use in chest radiography optimization studies. First, patient survey data were gathered for chest posterior anterior (PA) and lateral (LAT) examinations in a standard chest X-ray room over a period of one year, using a Caesium Iodide (CsI) based flat panel detector with automatic exposure control (AEC). Parameters surveyed included exposure index (EI), dose area product (DAP) and AEC exposure time. PA and LAT projections of the phantom were then compared to these values. Additionally, the equivalence in millimetres of poly (methyl methacrylate) (PMMA) was established for the different regions of the Lungman phantom (lungs and mediastinum). Finally, a voxel model of the Lungman phantom was developed by the segmentation of a volumetric dataset of the phantom acquired using CT scanning. Subsequently, the model was used in Monte Carlo simulations with PENELOPE/penEasy code to calculate the energy deposited in the organs of the phantom. This enabled comparison of the phantom tissue-equivalent materials with materials defined by ICRP 89 in terms of energy deposition. For the survey data, close agreement was found between phantom and the median values for the patient data (deviations ranged from 4% to 31%, one outlier). The phantom lung region is equivalent to 89 mm to 106 mm of PMMA, depending on tube voltage. Energy deposited in the phantom material compared to those for ICRP defined material differed by at most 36% in AP irradiations and 49% in PA irradiations.

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

    International Nuclear Information System (INIS)

    Matos, Andrea S.D. de; Campos, Tarcisio P.R. de

    2009-01-01

    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

  6. Design and fabrication of a realistic anthropomorphic heterogeneous head phantom for MR purposes.

    Directory of Open Access Journals (Sweden)

    Sossena Wood

    Full Text Available The purpose of this study is to design an anthropomorphic heterogeneous head phantom that can be used for MRI and other electromagnetic applications.An eight compartment, physical anthropomorphic head phantom was developed from a 3T MRI dataset of a healthy male. The designed phantom was successfully built and preliminarily evaluated through an application that involves electromagnetic-tissue interactions: MRI (due to it being an available resource. The developed phantom was filled with media possessing electromagnetic constitutive parameters that correspond to biological tissues at ~297 MHz. A preliminary comparison between an in-vivo human volunteer (based on whom the anthropomorphic head phantom was created and various phantoms types, one being the anthropomorphic heterogeneous head phantom, were performed using a 7 Tesla human MRI scanner.Echo planar imaging was performed and minimal ghosting and fluctuations were observed using the proposed anthropomorphic phantom. The magnetic field distributions (during MRI experiments at 7 Tesla and the scattering parameter (measured using a network analyzer were most comparable between the anthropomorphic heterogeneous head phantom and an in-vivo human volunteer.The developed anthropomorphic heterogeneous head phantom can be used as a resource to various researchers in applications that involve electromagnetic-biological tissue interactions such as MRI.

  7. Design and fabrication of a realistic anthropomorphic heterogeneous head phantom for MR purposes.

    Science.gov (United States)

    Wood, Sossena; Krishnamurthy, Narayanan; Santini, Tales; Raval, Shailesh B; Farhat, Nadim; Holmes, John Andy; Ibrahim, Tamer S

    2017-01-01

    The purpose of this study is to design an anthropomorphic heterogeneous head phantom that can be used for MRI and other electromagnetic applications. An eight compartment, physical anthropomorphic head phantom was developed from a 3T MRI dataset of a healthy male. The designed phantom was successfully built and preliminarily evaluated through an application that involves electromagnetic-tissue interactions: MRI (due to it being an available resource). The developed phantom was filled with media possessing electromagnetic constitutive parameters that correspond to biological tissues at ~297 MHz. A preliminary comparison between an in-vivo human volunteer (based on whom the anthropomorphic head phantom was created) and various phantoms types, one being the anthropomorphic heterogeneous head phantom, were performed using a 7 Tesla human MRI scanner. Echo planar imaging was performed and minimal ghosting and fluctuations were observed using the proposed anthropomorphic phantom. The magnetic field distributions (during MRI experiments at 7 Tesla) and the scattering parameter (measured using a network analyzer) were most comparable between the anthropomorphic heterogeneous head phantom and an in-vivo human volunteer. The developed anthropomorphic heterogeneous head phantom can be used as a resource to various researchers in applications that involve electromagnetic-biological tissue interactions such as MRI.

  8. Design and fabrication of a realistic anthropomorphic heterogeneous head phantom for MR purposes

    Science.gov (United States)

    Wood, Sossena; Krishnamurthy, Narayanan; Santini, Tales; Raval, Shailesh; Farhat, Nadim; Holmes, John Andy; Ibrahim, Tamer S.

    2017-01-01

    Objective The purpose of this study is to design an anthropomorphic heterogeneous head phantom that can be used for MRI and other electromagnetic applications. Materials and methods An eight compartment, physical anthropomorphic head phantom was developed from a 3T MRI dataset of a healthy male. The designed phantom was successfully built and preliminarily evaluated through an application that involves electromagnetic-tissue interactions: MRI (due to it being an available resource). The developed phantom was filled with media possessing electromagnetic constitutive parameters that correspond to biological tissues at ~297 MHz. A preliminary comparison between an in-vivo human volunteer (based on whom the anthropomorphic head phantom was created) and various phantoms types, one being the anthropomorphic heterogeneous head phantom, were performed using a 7 Tesla human MRI scanner. Results Echo planar imaging was performed and minimal ghosting and fluctuations were observed using the proposed anthropomorphic phantom. The magnetic field distributions (during MRI experiments at 7 Tesla) and the scattering parameter (measured using a network analyzer) were most comparable between the anthropomorphic heterogeneous head phantom and an in-vivo human volunteer. Conclusion The developed anthropomorphic heterogeneous head phantom can be used as a resource to various researchers in applications that involve electromagnetic-biological tissue interactions such as MRI. PMID:28806768

  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

    2016-07-08

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

    Science.gov (United States)

    Matthiä, Daniel; Berger, Thomas; Reitz, Günther

    2013-08-01

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

  11. Experimental IMRT breast dosimetry in a thorax phantom

    Energy Technology Data Exchange (ETDEWEB)

    Pimenta, Elsa B.; Campos, Tarcisio P.R.; Nogueira, Luciana B.; Lima, Andre C.S., E-mail: elsabpimenta@gmail.com, E-mail: tprcampos@pq.cnpq.br, E-mail: lucibn19@yahoo.com.br, E-mail: radioterapia.andre@gmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil); Centro de Tratamento em Radioterapia, Betim, MG (Brazil)

    2017-11-01

    Radiation therapy (RT) is an essential therapeutic method. RT is often used as adjuvant therapy in the treatment of breast cancer. The dose-volume restrictions of the organs at risk limit the prescribed dose to the target volume and biological and clinical effects may influence the final treatment outcome. The breast RT provides large risks to the adjacent organs and consequently the recommended dosimetry to the prescribed dose volume (PTV) is 50 Gy, lower than the most prescribed dose in other treatments (70-85 Gy). Such values implies in less tumor control compared to other sites. The present research proposal aimed to measure absorbed dose in a thorax phantom with synthetic breasts provided by an Intensity-Modulate Radiation Therapy (IMRT) protocol in a RT center. On the methodology, IMRT protocol was selected following recommendations from the Radiation Therapy Oncology Group (RTOG). Radiochromic films and a thorax simulator were prepared by the Ionizing Radiation Research Group (NRI). Dosimeters were calibrated on a selected linear accelerator (LINAC). The comparison of the dosimetry from treatment planning system (TPS), Xio (Elekta) and from experimental data was performed. The spatial distribution of the breast internal dose and in the adjacent organs was depicted by the experimental data. In the film's calibration, the quadratic polynomial fit presented a satisfactory coefficient. Two-dimensional dose profiles were obtained in the breast suggesting that films can supply details and information that TPS does not provide. At the phantom's dosimetry, the internal mean doses taken at the synthetic breast presented usual values above the prescribed dose, besides overall values were within the dosimetric MSKCC criterion. The non full reproduction of the build-up region in the films had occurred due to the asymmetrical positioning of the films in the inner breast, in addition to their non constant distance from the skin. The hot regions were present may

  12. Experimental IMRT breast dosimetry in a thorax phantom

    International Nuclear Information System (INIS)

    Pimenta, Elsa B.; Campos, Tarcisio P.R.; Nogueira, Luciana B.; Lima, Andre C.S.

    2017-01-01

    Radiation therapy (RT) is an essential therapeutic method. RT is often used as adjuvant therapy in the treatment of breast cancer. The dose-volume restrictions of the organs at risk limit the prescribed dose to the target volume and biological and clinical effects may influence the final treatment outcome. The breast RT provides large risks to the adjacent organs and consequently the recommended dosimetry to the prescribed dose volume (PTV) is 50 Gy, lower than the most prescribed dose in other treatments (70-85 Gy). Such values implies in less tumor control compared to other sites. The present research proposal aimed to measure absorbed dose in a thorax phantom with synthetic breasts provided by an Intensity-Modulate Radiation Therapy (IMRT) protocol in a RT center. On the methodology, IMRT protocol was selected following recommendations from the Radiation Therapy Oncology Group (RTOG). Radiochromic films and a thorax simulator were prepared by the Ionizing Radiation Research Group (NRI). Dosimeters were calibrated on a selected linear accelerator (LINAC). The comparison of the dosimetry from treatment planning system (TPS), Xio (Elekta) and from experimental data was performed. The spatial distribution of the breast internal dose and in the adjacent organs was depicted by the experimental data. In the film's calibration, the quadratic polynomial fit presented a satisfactory coefficient. Two-dimensional dose profiles were obtained in the breast suggesting that films can supply details and information that TPS does not provide. At the phantom's dosimetry, the internal mean doses taken at the synthetic breast presented usual values above the prescribed dose, besides overall values were within the dosimetric MSKCC criterion. The non full reproduction of the build-up region in the films had occurred due to the asymmetrical positioning of the films in the inner breast, in addition to their non constant distance from the skin. The hot regions were present may

  13. Monte Carlo Simulations for Homeland Security Using Anthropomorphic Phantoms

    International Nuclear Information System (INIS)

    Burns, Kimberly A.

    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. Monte Carlo calculations were performed to simulate healthcare workers in the operating room or trauma room at a hospital. The Monte Carlo Neutral Particle transport code MCNP5 was used for the modeling. The human body was modeled using Medical Internal Radiation Dose (MIRD-V) anthropomorphic phantoms originally developed at Oak Ridge National Laboratory (ORNL) under the specifications of International Commission on Radiation Protection (ICRP) Publication 23 and later altered at Georgia Tech (17). This study considered two possible contamination scenarios: uniform external contamination with no internal contamination and inhaled radioactive material without any external contamination. For both scenarios, the patients isotopes considered were 60 Co, 137 Cs, 131 I, 192 Ir, and 241 Am. For the externally contaminated patient, a uniform volume source two millimeters thick was placed around the skin of each anthropomorphic phantom to simulate a uniform source on the surface of the body. For the internally contaminated patients, the Dose and Risk Calculation software, DCAL, was used to determine the distribution of the isotopes in the internal organs. For both of the scenarios, the healthcare provider was placed 20-cm from the middle of the torso of the contaminated patient. The amount of energy deposited to the tissues and organs of the healthcare provider due to the internally and externally contaminated patients and in the patient in the case of external contamination was determined. The effective dose rate was calculated using the masses of the tissues and organ and tissue weighting factors from ICRP Publication 60. The effective dose rate for the

  14. 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)

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

    Science.gov (United States)

    Ramos, Susie Medeiros Oliveira; Glavam, Adriana Pereira; Kubo, Tadeu Takao Almodovar; de Sá, Lidia Vasconcellos

    2014-01-01

    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 99mTc-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. PMID:25741088

  16. Use of VAP3D software in the construction of pathological anthropomorphic phantoms for dosimetric evaluations

    International Nuclear Information System (INIS)

    Lima, Lindeval Fernandes de; Lima, Fernando R.A.

    2011-01-01

    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

  17. Anthropomorphic chest phantom imaging – The potential for dose creep in computed radiography

    International Nuclear Information System (INIS)

    Ma, W.K.; Hogg, P.; Tootell, A.; Manning, D.; Thomas, N.; Kane, T.; Kelly, J.; McKenzie, M.; Kitching, J.

    2013-01-01

    For film-based radiography the operator had to be exact in the selection of acquisition parameters or the image could easily become under- or over-exposed. By contrast, digital technology allows for a much greater tolerance of acquisition factor selection which would still give an image of acceptable diagnostic quality. In turn this greater tolerance allows for the operator to increase effective dose for little or no penalty in image quality. The purpose of this article is to determine how image quality and lesion visibility vary with effective dose (E) in order to identify how much overexposure could be tolerated within the radiograph. Using an anthropomorphic chest phantom with ground glass lesions we determined how perceptual image quality and E varied over a wide range of acquisition conditions. Perceptual image quality comprised of image quality and lesion visibility. E was calculated using Monte Carlo method; image quality was determined using a two alternative forced choice (2AFC) method and the quality criteria were partly informed from European guidelines. Five clinicians with significant experience in image reading scored the images for quality (intraclass correlation coefficient 0.869). Image quality and lesion visibility had a close correlation (R 2 > 0.8). The tolerance for over-exposure, whilst still acquiring an image of acceptable quality, increases with decreasing kV and increasing source to image distance (SID). The maximum over-exposure factor (ratio of maximum E to minimum E that produce images of acceptable quality) possible was 139 (at 125 cm and 60 kV). Given the phantom had characteristics similar to the human thorax we propose that that potential for overexposure in a human whilst still obtaining an image of acceptable perceptual image quality is very high. Further research into overexposure tolerance and dose creep should be undertaken

  18. 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)

    Inkoom, S.

    2014-08-01

    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

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

    Science.gov (United States)

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

    2014-11-01

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

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

    International Nuclear Information System (INIS)

    Papp, Cinthia M.

    2013-01-01

    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

  1. Design, manufacture, and evaluation of an anthropomorphic pelvic phantom purpose-built for radiotherapy dosimetric intercomparison

    International Nuclear Information System (INIS)

    Harrison, K. M.; Ebert, M. A.; Kron, T.; Howlett, S. J.; Cornes, D.; Hamilton, C. S.; Denham, J. W.

    2011-01-01

    Purpose: An anthropomorphic pelvic phantom was designed and constructed to meet specific criteria for multicenter radiotherapy dosimetric intercomparison. Methods: Three dimensional external and organ outlines were generated from a computed tomography image set of a male pelvis, forming the basis of design for an anatomically realistic phantom. Clinically relevant points of interest were selected throughout the dataset where point-dose values could be measured with thermoluminescence dosimeters and a small-volume ionization chamber. Following testing, three materials were selected and the phantom was manufactured using modern prototyping techniques into five separate coronal slices. Time lines and resource requirements for the phantom design and manufacture were recorded. The ability of the phantom to mimic the entire treatment chain was tested. Results: The phantom CT images indicated that organ densities and geometries were comparable to those of the original patient. The phantom proved simple to load for dosimetry and rapid to assemble. Due to heat release during manufacture, small air gaps and density heterogeneities were present throughout the phantom. The overall cost for production of the prototype phantom was comparable to other commercial anthropomorphic phantoms. The phantom was shown to be suitable for use as a ''patient'' to mimic the entire treatment chain for typical external beam radiotherapy for prostate and rectal cancer. Conclusions: The phantom constructed for the present study incorporates all characteristics necessary for accurate Level III intercomparison studies. Following use in an extensive Level III dosimetric comparison over a large time scale and geographic area, the phantom retained mechanical stability and did not show signs of radiation-induced degradation.

  2. Attributes of a real and computational female thorax phantom for dosimetry; Atributos de um fantoma computacional e real de tronco feminino para dosimetria

    Energy Technology Data Exchange (ETDEWEB)

    Maia, Margareth; Campos, Tarcisio Passos Ribeiro de [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Programa de Pos-graduacao em Ciencias e Tecnicas Nucleares]. E-mail: campos@nuclear.ufmg.br

    2005-07-01

    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

  3. Development and characterization of an anthropomorphic breast software phantom based upon region-growing algorithm

    Science.gov (United States)

    Bakic, Predrag R.; Zhang, Cuiping; Maidment, Andrew D. A.

    2011-01-01

    Purpose: We present a novel algorithm for computer simulation of breast anatomy for generation of anthropomorphic software breast phantoms. A realistic breast simulation is necessary for preclinical validation of volumetric imaging modalities.Methods: The anthropomorphic software breast phantom simulates the skin, regions of adipose and fibroglandular tissue, and the matrix of Cooper’s ligaments and adipose compartments. The adipose compartments are simulated using a seeded region-growing algorithm; compartments are grown from a set of seed points with specific orientation and growing speed. The resulting adipose compartments vary in shape and size similar to real breasts; the adipose region has a compact coverage by adipose compartments of various sizes, while the fibroglandular region has fewer, more widely separated adipose compartments. Simulation parameters can be selected to cover the breadth of variations in breast anatomy observed clinically.Results: When simulating breasts of the same glandularity with different numbers of adipose compartments, the average compartment volume was proportional to the phantom size and inversely proportional to the number of simulated compartments. The use of the software phantom in clinical image simulation is illustrated by synthetic digital breast tomosynthesis images of the phantom. The proposed phantom design was capable of simulating breasts of different size, glandularity, and adipose compartment distribution. The region-growing approach allowed us to simulate adipose compartments with various size and shape. Qualitatively, simulated x-ray projections of the phantoms, generated using the proposed algorithm, have a more realistic appearance compared to previous versions of the phantom.Conclusions: A new algorithm for computer simulation of breast anatomy has been proposed that improved the realism of the anthropomorphic software breast phantom. PMID:21815391

  4. Skin Dosimetry in Breast Teletherapy on a Phantom Anthropomorphic and Anthropometric Phantom

    International Nuclear Information System (INIS)

    Batista Nogueira, Luciana; Lemos Silva, Hugo Leonardo; Donato da Silva, Sabrina; Passos Ribeiro Campos, Tarcisio

    2015-01-01

    This paper addresses the breast teletherapy dosimetry. The goal is to evaluate and compare absorbed doses in equivalent skin tissue, TE-skin, of an anthropomorphic and anthropometric breast phantom submitted to breast radiotherapy. The methodology involved the reproduction of a set of tomographic images of the phantom; the elaboration of conformational radiotherapy planning in the SOMAVISION and CadPlan (TPS) software; and the synthetic breast irradiation by parallel opposed fields in 3D conformal teletherapy at 6 MV linear accelerator Clinac-2100 C from VARIAN with prescribed dose (PD) of 180 cGy to the target volume (PTV), referent to the glandular tissue. Radiochromic films EBT2 were selected as dosimeters. Two independent calibration processes of films with solid water Gammex 457 plates and water filled box were produced. Curves of optical density (OD) versus absorbed dose were produced. Dosimeters were positioned in the external region of the breast phantom in contact with TE-skin, area of 4.0 cm 2 each. The irradiation process was prepared in duplicate to check the reproducibility of the technique. The radiochromic films were scanned and their response in RGB (Red, Green, Blue) analyzed by the ImageJ software. The optical density was obtained and converted to dose based on the calibration curves. Thus, the spatial dose distribution in the skin was reproduced. The absorbed doses measured on the radiochromic films in TE-skin showed values between upper and lower quadrants at 9 o'clock in the range of 54% of PD, between the upper and lower quadrants 3 o'clock in the range of 72% and 6 o'clock at the lower quadrant in the range of 68 % of PD. The values are ±64% (p <0.05) according to the TPS. It is concluded that the depth dose measured in solid water plates or water box reproduce equivalent dose values for both calibration processes of the radiochromic films. It was observed that the skin received doses ranging from 50% to 78% of the prescribed

  5. Skin Dosimetry in Breast Teletherapy on a Phantom Anthropomorphic and Anthropometric Phantom

    Energy Technology Data Exchange (ETDEWEB)

    Batista Nogueira, Luciana [Anatomy and Imaging Department, Federal University of Minas Gerais, Belo Horizonte (Brazil); Lemos Silva, Hugo Leonardo [Santa Casa Hospital, Belo Horizonte (Brazil); Donato da Silva, Sabrina; Passos Ribeiro Campos, Tarcisio [Nuclear Engineering Department, Federal University of Minas Gerais, Belo Horizonte (Brazil)

    2015-07-01

    This paper addresses the breast teletherapy dosimetry. The goal is to evaluate and compare absorbed doses in equivalent skin tissue, TE-skin, of an anthropomorphic and anthropometric breast phantom submitted to breast radiotherapy. The methodology involved the reproduction of a set of tomographic images of the phantom; the elaboration of conformational radiotherapy planning in the SOMAVISION and CadPlan (TPS) software; and the synthetic breast irradiation by parallel opposed fields in 3D conformal teletherapy at 6 MV linear accelerator Clinac-2100 C from VARIAN with prescribed dose (PD) of 180 cGy to the target volume (PTV), referent to the glandular tissue. Radiochromic films EBT2 were selected as dosimeters. Two independent calibration processes of films with solid water Gammex 457 plates and water filled box were produced. Curves of optical density (OD) versus absorbed dose were produced. Dosimeters were positioned in the external region of the breast phantom in contact with TE-skin, area of 4.0 cm{sup 2} each. The irradiation process was prepared in duplicate to check the reproducibility of the technique. The radiochromic films were scanned and their response in RGB (Red, Green, Blue) analyzed by the ImageJ software. The optical density was obtained and converted to dose based on the calibration curves. Thus, the spatial dose distribution in the skin was reproduced. The absorbed doses measured on the radiochromic films in TE-skin showed values between upper and lower quadrants at 9 o'clock in the range of 54% of PD, between the upper and lower quadrants 3 o'clock in the range of 72% and 6 o'clock at the lower quadrant in the range of 68 % of PD. The values are ±64% (p <0.05) according to the TPS. It is concluded that the depth dose measured in solid water plates or water box reproduce equivalent dose values for both calibration processes of the radiochromic films. It was observed that the skin received doses ranging from 50% to 78% of the

  6. Verification of gamma knife based fractionated radiosurgery with newly developed head-thorax phantom

    International Nuclear Information System (INIS)

    Bisht, Raj Kishor; Kale, Shashank Sharad; Natanasabapathi, Gopishankar; Singh, Manmohan Jit; Agarwal, Deepak; Garg, Ajay; Rath, Goura Kishore; Julka, Pramod Kumar; Kumar, Pratik; Thulkar, Sanjay; Sharma, Bhawani Shankar

    2016-01-01

    Objective: Purpose of the study is to verify the Gamma Knife Extend™ system (ES) based fractionated stereotactic radiosurgery with newly developed head-thorax phantom. Methods: Phantoms are extensively used to measure radiation dose and verify treatment plan in radiotherapy. A human upper body shaped phantom with thorax was designed to simulate fractionated stereotactic radiosurgery using Extend™ system of Gamma Knife. The central component of the phantom aids in performing radiological precision test, dosimetric evaluation and treatment verification. A hollow right circular cylindrical space of diameter 7.0 cm was created at the centre of this component to place various dosimetric devices using suitable adaptors. The phantom is made of poly methyl methacrylate (PMMA), a transparent thermoplastic material. Two sets of disk assemblies were designed to place dosimetric films in (1) horizontal (xy) and (2) vertical (xz) planes. Specific cylindrical adaptors were designed to place thimble ionization chamber inside phantom for point dose recording along xz axis. EBT3 Gafchromic films were used to analyze and map radiation field. The focal precision test was performed using 4 mm collimator shot in phantom to check radiological accuracy of treatment. The phantom head position within the Extend™ frame was estimated using encoded aperture measurement of repositioning check tool (RCT). For treatment verification, the phantom with inserts for film and ion chamber was scanned in reference treatment position using X-ray computed tomography (CT) machine and acquired stereotactic images were transferred into Leksell Gammaplan (LGP). A patient treatment plan with hypo-fractionated regimen was delivered and identical fractions were compared using EBT3 films and in-house MATLAB codes. Results: RCT measurement showed an overall positional accuracy of 0.265 mm (range 0.223 mm–0.343 mm). Gamma index analysis across fractions exhibited close agreement between LGP and film

  7. Performance of an automatic dose control system for CT: anthropomorphic phantom studies.

    Science.gov (United States)

    Gosch, D; Stumpp, P; Kahn, T; Nagel, H D

    2011-02-01

    To assess the performance and to provide more detailed insight into characteristics and limitations of devices for automatic dose control (ADC) in CT. A comprehensive study on DoseRight 2.0, the ADC system provided by Philips for its Brilliance CT scanners, was conducted with assorted tests using an anthropomorphic phantom that allowed simulation of the operation of the system under almost realistic conditions. The scan protocol settings for the neck, chest and abdomen with pelvis were identical to those applied in the clinical routine. Using the appropriate ADC functionalities, dose reductions equal 40% for the neck, 20% for the chest and 10% for the abdomen with pelvis. Larger dose reductions can be expected for average patients, since their attenuating properties differ significantly from the anthropomorphic phantom. Adverse effects due to increased image noise were only moderate as a consequence of the "adequate noise system" design and the complementary use of adaptive filtration. The results of specific tests also provided deeper insight into the operation of the ADC system that helps to identify the causes of suspected malfunctions and to prevent potential pitfalls. Tests with anthropomorphic phantoms allow verification of the characteristics of devices for ADC in CT under almost realistic conditions. However, differences in phantom shape and material composition require supplementary patient studies on representative patient groups. © Georg Thieme Verlag KG Stuttgart · New York.

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

    Science.gov (United States)

    Schläger, Martin

    2011-03-01

    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 Institute 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 Jülich (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.

  9. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-06-15

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

  11. 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.

  12. 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.

  13. Development and liver of phantom anthropomorphic application for use in radiology

    International Nuclear Information System (INIS)

    Melo, M.G.; Silva, L.F.; Ferreira, F. C.L.; Cunha, C.J.; Paschoal, C.M.M.

    2015-01-01

    The use of artificial ionizing radiation has also been employed in several areas, namely: medicine, agriculture, industry, ink curing etc. However, the use of radiation for medical purposes of diagnosis or therapy is being treated with more attention due to its increased use and the use of simulators object for quality control and training of professionals. The phantoms and are used to aid radiographic procedures, they may simulate a part of the body, both in its form as mass, density, and attenuation. The objective of this work was the development and application of liver anthropomorphic phantom for use in diagnostic radiology and training professionals. The construction of the liver anthropomorphic phantom was through literature and it was noticed that the use of phantoms are relatively low. For the construction of the mold of the phantom was used an adult human liver with early cirrhosis that was preserved in formalin for teaching demonstrations in Prof. Human Anatomy Museum collection Osvaldo Cruz of milk from the Federal University of Sergipe. With this work, we emphasize the need for the control program and quality assurance in radiology doctor to ensure image quality and low exposure of patients and professionals, since the radiological examinations are extremely important, because its contribution decisively in medical diagnosis. (authors)

  14. 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)

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

    Directory of Open Access Journals (Sweden)

    Taynná Vernalha Rocha Almeida

    2016-04-01

    Full Text Available Abstract Objective: To evaluate three-dimensional translational setup errors and residual errors in image-guided radiosurgery, comparing frameless and frame-based techniques, using an anthropomorphic phantom. Materials and Methods: We initially used specific phantoms for the calibration and quality control of the image-guided system. For the hidden target test, we used an Alderson Radiation Therapy (ART-210 anthropomorphic head phantom, into which we inserted four 5mm metal balls to simulate target treatment volumes. Computed tomography images were the taken with the head phantom properly positioned for frameless and frame-based radiosurgery. Results: For the frameless technique, the mean error magnitude was 0.22 ± 0.04 mm for setup errors and 0.14 ± 0.02 mm for residual errors, the combined uncertainty being 0.28 mm and 0.16 mm, respectively. For the frame-based technique, the mean error magnitude was 0.73 ± 0.14 mm for setup errors and 0.31 ± 0.04 mm for residual errors, the combined uncertainty being 1.15 mm and 0.63 mm, respectively. Conclusion: The mean values, standard deviations, and combined uncertainties showed no evidence of a significant differences between the two techniques when the head phantom ART-210 was used.

  16. Time-resolved plastic scintillator dosimetry in a dynamic thorax phantom

    DEFF Research Database (Denmark)

    Sibolt, Patrik; Andersen, Claus E.; Ottosson, Wiviann

    2017-01-01

    in a lung. The phantom motion was controlled by a script in-house developed using LabVIEW (National Instruments) and synchronized with the in-house developed ME40 scintillator dosimetry system (DTU Nutech). The dose in the center of the tumor was measured, using a BCF-60 plastic scintillator detector (Saint...... respiratory motion and lack of lateral charged particle equilibrium, motivating quality assurance based on a system like the one presented in this study. It has specifically been demonstrated that reliable time-resolved scintillator dosimetry in a dynamic thorax phantom can play an essential role in dose...

  17. Dosimetric reproduction of a left-breast 3DCRT field-in-field radiation therapy planning in an anthropomorphic and anthropometric phantom

    International Nuclear Information System (INIS)

    Nogueira, Luciana B.; Aquino, Jean Carlos; Campos, Tarcísio P. Ribeiro

    2017-01-01

    The proposal of this study was to reproduce the dosimetry established in a treatment planning system (TPS) following a 3D conformational radiation therapy (3DCRT) protocol of two parallel-opposite fields applied to the left-breast in a thorax phantom, with the use of the field-in-field technique. Computed tomography (CT) images of the anthropomorphic and anthropometric phantom of the thorax with mobile breasts were generated. This phantom was developed by the NRI / UFMG research group. The generated images were transferred to the planning system XiO version-5 for the elaboration of the breast tele therapeutic planning with 2 Gy per fraction, in 25 fractions, with prescribed dose of 50 Gy. A set of ten EBT2 radiochromic films were irradiated at different doses. The values of RGB (Red, Green, Blue) of the radiochromic films were obtained by scanning and data transformed in optical density (OD), whose values were used to construct the calibration curve. EBT2 radiochromic films were positioned outside and inside of the thorax phantom: internally in the right and left lungs, on the face of the heart, in the glandular breast tissue-equivalent (TE) and in the left breast skin. After phantom radiation at the linear accelerator 6 MV Elekta Precise reproducing the 3DCRT, the radiochromic films were digitized after 24 h of exposure. The measurements of the intensities of the films in RGB were measured in the software ImageJ, transformed in optical density and converted in bidimensional dose distributions, applying the calibration curve. The experimental dosimetric data were analyzed and compared with values generated in the TPS. In addition, graphics and dose-volume histograms (DVH) were developed. The dose measurements in the glandular-TE in breast did not present statistically significant differences in relation to values at equivalent positions generated in the TPS. The organs at risk received doses below the reference values, according to TPS. It was verified the

  18. Dosimetric reproduction of a left-breast 3DCRT field-in-field radiation therapy planning in an anthropomorphic and anthropometric phantom

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, Luciana B., E-mail: lucibn19@yahoo.com.br, E-mail: jonymarques@uol.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Anatomia e Imagem; Barsanelli, Cristiane; Geraldo, Jony M., E-mail: cbarsanelli@yahoo.com.br [Hospital Luxemburgo, Instituto Mário Penna, Belo Horizonte, MG (Brazil); Aquino, Jean Carlos; Campos, Tarcísio P. Ribeiro, E-mail: jeancarlosaquino@outlook.com, E-mail: tprcampos@yahoo.com.br [Universidade Federal de Minas Gerais (UGMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear

    2017-07-01

    The proposal of this study was to reproduce the dosimetry established in a treatment planning system (TPS) following a 3D conformational radiation therapy (3DCRT) protocol of two parallel-opposite fields applied to the left-breast in a thorax phantom, with the use of the field-in-field technique. Computed tomography (CT) images of the anthropomorphic and anthropometric phantom of the thorax with mobile breasts were generated. This phantom was developed by the NRI / UFMG research group. The generated images were transferred to the planning system XiO version-5 for the elaboration of the breast tele therapeutic planning with 2 Gy per fraction, in 25 fractions, with prescribed dose of 50 Gy. A set of ten EBT2 radiochromic films were irradiated at different doses. The values of RGB (Red, Green, Blue) of the radiochromic films were obtained by scanning and data transformed in optical density (OD), whose values were used to construct the calibration curve. EBT2 radiochromic films were positioned outside and inside of the thorax phantom: internally in the right and left lungs, on the face of the heart, in the glandular breast tissue-equivalent (TE) and in the left breast skin. After phantom radiation at the linear accelerator 6 MV Elekta Precise reproducing the 3DCRT, the radiochromic films were digitized after 24 h of exposure. The measurements of the intensities of the films in RGB were measured in the software ImageJ, transformed in optical density and converted in bidimensional dose distributions, applying the calibration curve. The experimental dosimetric data were analyzed and compared with values generated in the TPS. In addition, graphics and dose-volume histograms (DVH) were developed. The dose measurements in the glandular-TE in breast did not present statistically significant differences in relation to values at equivalent positions generated in the TPS. The organs at risk received doses below the reference values, according to TPS. It was verified the

  19. An anthropomorphic abdominal phantom for deformable image registration accuracy validation in adaptive radiation therapy.

    Science.gov (United States)

    Liao, Yuliang; Wang, Linjing; Xu, Xiangdong; Chen, Haibin; Chen, Jiawei; Zhang, Guoqian; Lei, Huaiyu; Wang, Ruihao; Zhang, Shuxu; Gu, Xuejun; Zhen, Xin; Zhou, Linghong

    2017-06-01

    To design and construct a three-dimensional (3D) anthropomorphic abdominal phantom for geometric accuracy and dose summation accuracy evaluations of deformable image registration (DIR) algorithms for adaptive radiation therapy (ART). Organ molds, including liver, kidney, spleen, stomach, vertebra, and two metastasis tumors, were 3D printed using contours from an ovarian cancer patient. The organ molds were molded with deformable gels made of different mixtures of polyvinyl chloride (PVC) and the softener dioctyl terephthalate. Gels with different densities were obtained by a polynomial fitting curve that described the relation between the Hounsfield unit (HU) and PVC-softener blending ratio. The rigid vertebras were constructed by molding of white cement and cellulose pulp. The final abdominal phantom was assembled by arranging all the fabricated organs inside a hollow dummy according to their anatomies, and sealed by deformable gel with averaged HU of muscle and fat. Fiducial landmarks were embedded inside the phantom for spatial accuracy and dose accumulation accuracy studies. Two channels were excavated to facilitate ionization chamber insertion for dosimetric measurements. Phantom properties such as deformable gel elasticity and HU stability were studied. The dosimetric measurement accuracy in the phantom was performed, and the DIR accuracies of three DIR algorithms available in the open source DIR toolkit-DIRART were also validated. The constructed deformable gel showed elastic behavior and was stable in HU values over times, proving to be a practical material for the deformable phantom. The constructed abdominal phantom consisted of realistic anatomies in terms of both anatomical shapes and densities when compared with its reference patient. The dosimetric measurements showed a good agreement with the calculated doses from the treatment planning system. Fiducial-based accuracy analysis conducted on the constructed phantom demonstrated the feasibility of

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-06-15

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

  1. X-ray properties of an anthropomorphic breast phantom for MRI and x-ray imaging

    Energy Technology Data Exchange (ETDEWEB)

    Freed, Melanie; Badal, Andreu; Jennings, Robert J; Myers, Kyle J; Badano, Aldo [Division of Imaging and Applied Mathematics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, US Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, MD 20993-0002 (United States); Heras, Hugo de las, E-mail: melanie.freed@fda.hhs.gov [Division of Radiological Devices, Office of In Vitro Device Evaluation and Safety, Center for Devices and Radiological Health, US Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, MD 20993-0002 (United States)

    2011-06-21

    The purpose of this study is to characterize the x-ray properties of a dual-modality, anthropomorphic breast phantom whose MRI properties have been previously evaluated. The goal of this phantom is to provide a platform for optimization and standardization of two- and three-dimensional x-ray and MRI breast imaging modalities for the purpose of lesion detection and discrimination. The phantom is constructed using a mixture of lard and egg whites, resulting in a variable, tissue-mimicking structure with separate adipose- and glandular-mimicking components. The phantom can be produced with either a compressed or uncompressed shape. Mass attenuation coefficients of the phantom materials were estimated using elemental compositions from the USDA National Nutrient Database for Standard Reference and the atomic interaction models from the Monte Carlo code PENELOPE and compared with human values from the literature. The image structure was examined quantitatively by calculating and comparing spatial covariance matrices of the phantom and patient mammography images. Finally, a computerized version of the phantom was created by segmenting a computed tomography scan and used to simulate x-ray scatter of the phantom in a mammography geometry. Mass attenuation coefficients of the phantom materials were within 20% and 15% of the values for adipose and glandular tissues, respectively, which is within the estimation error of these values. Matching was improved at higher energies (>20 keV). Tissue structures in the phantom have a size similar to those in the patient data, but are slightly larger on average. Correlations in the patient data appear to be longer than those in the phantom data in the anterior-posterior direction; however, they are within the error bars of the measurement. Simulated scatter-to-primary ratio values of the phantom images were as high as 85% in some areas and were strongly affected by the heterogeneous nature of the phantom. Key physical x-ray properties of

  2. Simulating effects of brain atrophy in longitudinal PET imaging with an anthropomorphic brain phantom

    DEFF Research Database (Denmark)

    Jonasson, L S; Axelsson, J; Riklund, K

    2017-01-01

    cameras and reconstruction algorithms. Here, a 3D-printed anthropomorphic brain phantom with attachable striata in three sizes was designed to enable controlled volumetric changes. Using a method to eliminate the non-radioactive plastic wall, and manipulating BP levels by adding different number of events......, as the amplitude of the PVE on the BP differs depending on where in the striatum the change occurred. Therefore, to correctly interpret age-related longitudinal changes in the BP, we must account for volumetric changes also within a structure, rather than across the whole volume. The present 3D-printing technology...

  3. 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

    2015-07-08

    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

  4. Effectiveness of thyroid gland shielding in dental CBCT using a paediatric anthropomorphic phantom.

    Science.gov (United States)

    Hidalgo, A; Davies, J; Horner, K; Theodorakou, C

    2015-01-01

    The purpose of the study is to evaluate the effectiveness of thyroid shielding in dental CBCT examinations using a paediatric anthropomorphic phantom. An ATOM(®) 706-C anthropomorphic phantom (Computerized Imaging Reference Systems Inc., Norfolk, VA) representing a 10-year-old child was loaded with six thermoluminescent dosemeters positioned at the level of the thyroid gland. Absorbed doses to the thyroid were measured for five commercially available thyroid shields using a large field of view (FOV). A statistically significant thyroid gland dose reduction was found using thyroid shielding for paediatric CBCT examinations for a large FOV. In addition, a statistically significant difference in thyroid gland doses was found depending on the position of the thyroid gland. There was little difference in the effectiveness of thyroid shielding when using a lead vs a lead-equivalent thyroid shield. Similar dose reduction was found using 0.25- and 0.50-mm lead-equivalent thyroid shields. Thyroid shields are to be recommended when undertaking large FOV CBCT examinations on young patients.

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

    International Nuclear Information System (INIS)

    Silva, Cleuza Helena Teixeira; Campos, Tarcisio Passos Ribeiro de

    2005-01-01

    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

  6. Comparison of cone beam SPECT with conventional SPECT by means of cardiac-thorax phantom

    International Nuclear Information System (INIS)

    McGrath, M.A.; Manglos, S.H.

    1989-01-01

    Because of poor energy characteristics of Tl-201 used for myocardial perfusion imaging, the high sensitivity of cone-beam collimation is highly desirable. Using a cardiac-thorax phantom, the authors have compared single photon emission computed tomographic (SPECT) images obtained with a cone-beam collimator to those from a parallel hole collimator commonly used for thallium studies. A water-filled circular phantom with a cardiac insert was imaged. The myocardial shell was filled with Tl-201 (220 μCi). Two solid inserts within the myocardium simulated perfusion defects. The phantom ignores truncation effects in this preliminary experiment. For the authors' collimator, the resolution was designed to be similar to the authors' all-purpose, parallel-hole collimator at 10 cm. The focal length was 50 cm. The experimental protocol was chosen to be similar to their clinical protocol. A filtered back projection algorithm was used for cone-beam data. The same algorithm was used for the parallel-hole data, but with focal length set to infinity

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Da; Li, Xinhua; Liu, Bob [Division of Diagnostic Imaging Physics and Webster Center for Advanced Research and Education in Radiation, Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts 02114 (United States); Gao, Yiming; Xu, X. George [Nuclear Engineering Program, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

    2013-08-15

    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.Methods: A standard ATOM phantom has densely located holes (in 3 × 3 cm or 1.5 × 1.5 cm grids), which are too small (5 mm in diameter) to host many types of dosimeters, including the nanoDots. The authors modified the conventional way in which nanoDots are used, by removing the OSL disks from the holders before inserting them inside a standard ATOM phantom for dose measurements. The authors solved three technical difficulties introduced by this modification: (1) energy dependent dose calibration for raw OSL readings; (2) influence of the brief background exposure of OSL disks to dimmed room light; (3) correct pairing between the dose readings and measurement locations. The authors acquired 100 dose measurements at various positions in the phantom, which was scanned using a clinical chest protocol with both angular and z-axis tube current modulations.Results: Dose calibration was performed according to the beam qualities inside the phantom as determined from an established Monte Carlo model of the scanner. The influence of the brief exposure to dimmed room light was evaluated and deemed negligible. Pairing between the OSL readings and measurement locations was ensured by the experimental design. The organ doses measured for a routine adult chest scan protocol ranged from 9.4 to 18.8 mGy, depending on the composition, location, and surrounding anatomy of the organs. The dose distribution across different slices of the phantom strongly depended on the z-axis mA modulation. In the same slice, doses to the soft tissues other than the spinal cord demonstrated

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

    International Nuclear Information System (INIS)

    Hermosilla, A.; Diaz Londono, G.; Garcia, M.; Ruiz, F.; Andrade, P.; Perez, A.

    2014-01-01

    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. (authors)

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

    International Nuclear Information System (INIS)

    Wells, J; Wilson, J; Zhang, Y; Samei, E; Ravin, Carl E.

    2014-01-01

    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

  10. SU-F-T-292: Imaging and Radiation Oncology Core (IROC) Houston QA Center’s Anthropomorphic Phantom Program

    International Nuclear Information System (INIS)

    Mehrens, H; Lewis, B; Lujano, C; Nguyen, T; Hernandez, N; Alvarez, P; Molineu, A; Followill, D

    2016-01-01

    Purpose: To describe the results of IROC Houston’s international and domestic end-to-end QA phantom irradiations. Methods: IROC Houston has anthropomorphic lung, liver, head and neck, prostate, SRS and spine phantoms that are used for credentialing and quality assurance purposes. The phantoms include structures that closely mimic targets and organs at risk and are made from tissue equivalent materials: high impact polystyrene, solid water, cork and acrylic. Motion tables are used to mimic breathing motion for some lung and liver phantoms. Dose is measured with TLD and radiochromic film in various planes within the target of the phantoms. Results: The most common phantom requested is the head and neck followed by the lung phantom. The head and neck phantom was sent to 800 domestic and 148 international sites between 2011 and 2015, with average pass rates of 89% and 92%, respectively. During the past five years, a general upward trend exists regarding demand for the lung phantom for both international and domestic sites with international sites more than tripling from 5 (2011) to 16 (2015) and domestic sites doubling from 66 (2011) to 152 (2015). The pass rate for lung phantoms has been consistent from year to year despite this large increase in the number of phantoms irradiated with an average pass rate of 85% (domestic) and 95% (international) sites. The percentage of lung phantoms used in combination with motions tables increased from 38% to 79% over the 5 year time span. Conclusion: The number of domestic and international sites irradiating the head and neck and lung phantoms continues to increase and the pass rates remained constant. These end-to-end QA tests continue to be a crucial part of clinical trial credentialing and institution quality assurance. This investigation was supported by IROC grant CA180803 awarded by the NCI.

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

    International Nuclear Information System (INIS)

    Dauer, L. T.; Branets, I.; Stabulas-Savage, J.; Quinn, B.; Miodownik, D.; Dauer, Z. L.; Colosi, D.; Hershkowitz, D.; Goren, A.

    2014-01-01

    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)

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

    International Nuclear Information System (INIS)

    Palma, R.; Gastelo, E.; Paucar, R.; Tolentino, D.; Herrera, J.; Armas, D.

    2014-08-01

    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 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)

  13. Dose profile study in head CT scans using a male anthropomorphic phantom

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Alvaro M.L.; Santana, Priscila do C.; Mourao, Arnaldo P., E-mail: amlgphys@gmail.com, E-mail: pridili@gmail.com, E-mail: apratabhz@gmail.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte (Brazil). Departamento de Engenharia Nuclear; Centro Federal de Educação Tecnológica de Minas Gerais (CEFET-MG), Belo Horizonte, MG (Brazil)

    2017-11-01

    Computed tomography (CT) test is an efficient and non-invasive method to obtain data about internal structures of the human body. CT scans contribute with the highest absorbed doses in population due X-ray beam attenuation and it has raised concern in radiosensitive tissues. Techniques for the optimization of CT scanning protocols in diagnostic services have been developing with the objective of decreasing the absorbed dose in the patient, aiming image quality within acceptable parameters for diagnosis by noise control. Routine head scans were performed using GE CT scan of 64 channels programmed with automatic exposure control and voltages of 80, 100 and 120 kV attaching the noise index in approximately 0.5%, using the tool of smart mA. An anthropomorphic adult male phantom was used and radiochromic film strips were placed to measure the absorbed dose deposited in areas such as the lens, thyroid and pituitary for study of dose deposited in these important areas containing high radiosensitive tissues. Different head scans were performed using optimized values of mA.s for the different voltages. The absorbed dose measured by the film strips were in the range of the 0.58 and 44.36 mGy. The analysis of noise in the images is within the acceptable levels for diagnosis, and the optimized protocol happens with the voltage of 100 kV. The use of other voltage values can allow obtain better protocols for head scans. (author)

  14. Third generation anthropomorphic physical phantom for mammography and DBT: incorporating voxelized 3D printing and uniform chest wall QC region

    Science.gov (United States)

    Zhao, Christine; Solomon, Justin; Sturgeon, Gregory M.; Gehm, Michael E.; Catenacci, Matthew; Wiley, Benjamin J.; Samei, Ehsan; Lo, Joseph Y.

    2017-03-01

    Physical breast phantoms provide a standard method to test, optimize, and develop clinical mammography systems, including new digital breast tomosynthesis (DBT) systems. In previous work, we produced an anthropomorphic phantom based on 500x500x500 μm breast CT data using commercial 3D printing. We now introduce an improved phantom based on a new cohort of virtual models with 155x155x155 μm voxels and fabricated through voxelized 3D printing and dithering, which confer higher resolution and greater control over contrast. This new generation includes a uniform chest wall extension for evaluating conventional QC metrics. The uniform region contains a grayscale step wedge, chest wall coverage markers, fiducial markers, spheres, and metal ink stickers of line pairs and edges to assess contrast, resolution, artifact spread function, MTF, and other criteria. We also experimented with doping photopolymer material with calcium, iodine, and zinc to increase our current contrast. In particular, zinc was discovered to significantly increase attenuation beyond 100% breast density with a linear relationship between zinc concentration and attenuation or breast density. This linear relationship was retained when the zinc-doped material was applied in conjunction with 3D printing. As we move towards our long term goal of phantoms that are indistinguishable from patients, this new generation of anthropomorphic physical breast phantom validates our voxelized printing process, demonstrates the utility of a uniform QC region with features from 3D printing and metal ink stickers, and shows potential for improved contrast via doping.

  15. Simulating effects of brain atrophy in longitudinal PET imaging with an anthropomorphic brain phantom

    Science.gov (United States)

    Jonasson, L. S.; Axelsson, J.; Riklund, K.; Boraxbekk, C. J.

    2017-07-01

    In longitudinal positron emission tomography (PET), the presence of volumetric changes over time can lead to an overestimation or underestimation of the true changes in the quantified PET signal due to the partial volume effect (PVE) introduced by the limited spatial resolution of existing PET cameras and reconstruction algorithms. Here, a 3D-printed anthropomorphic brain phantom with attachable striata in three sizes was designed to enable controlled volumetric changes. Using a method to eliminate the non-radioactive plastic wall, and manipulating BP levels by adding different number of events from list-mode acquisitions, we investigated the artificial volume dependence of BP due to PVE, and potential bias arising from varying BP. Comparing multiple reconstruction algorithms we found that a high-resolution ordered-subsets maximization algorithm with spatially variant point-spread function resolution modeling provided the most accurate data. For striatum, the BP changed by 0.08% for every 1% volume change, but for smaller volumes such as the posterior caudate the artificial change in BP was as high as 0.7% per 1% volume change. A simple gross correction for striatal volume is unsatisfactory, as the amplitude of the PVE on the BP differs depending on where in the striatum the change occurred. Therefore, to correctly interpret age-related longitudinal changes in the BP, we must account for volumetric changes also within a structure, rather than across the whole volume. The present 3D-printing technology, combined with the wall removal method, can be implemented to gain knowledge about the predictable bias introduced by the PVE differences in uptake regions of varying shape.

  16. Impact of Reconstruction Algorithms and Gender-Associated Anatomy on Coronary Calcium Scoring with CT: An Anthropomorphic Phantom Study.

    Science.gov (United States)

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

    2016-12-01

    Different computed tomography imaging protocols and patient characteristics can impact the accuracy and precision of the calcium score and may lead to inconsistent patient treatment recommendations. The aim of this work was to determine the impact of reconstruction algorithm and gender characteristics on coronary artery calcium scoring based on a phantom study using computed tomography. Four synthetic heart vessels with vessel diameters corresponding to female and male left main and left circumflex arteries containing calcification-mimicking materials (200-1000 HU) were inserted into a thorax phantom and were scanned with and without female breast plates (male and female phantoms, respectively). Ten scans were acquired and were reconstructed at 3-mm slices using filtered-back projection (FBP) and iterative reconstruction with medium and strong denoising (IR3 and IR5) algorithms. Agatston and calcium volume scores were estimated for each vessel. Calcium scores for each vessel and the total calcium score (summation of all four vessels) were compared between the two phantoms to quantify the impact of the breast plates and reconstruction parameters. Calcium scores were also compared among vessels of different diameters to investigate the impact of the vessel size. The calcium scores were significantly larger for FBP reconstruction (FBP > IR3>IR5). Agatston scores (calcium volume score) for vessels in the male phantom scans were on average 4.8% (2.9%), 8.2% (7.1%), and 10.5% (9.4%) higher compared to those in the female phantom with FBP, IR3, and IR5, respectively, when exposure was conserved across phantoms. The total calcium scores from the male phantom were significantly larger than those from the female phantom (P phantom. Calcium scores significantly decreased with iterative reconstruction and tended to be underestimated for female anatomy (smaller vessels and presence of breast plates). Published by Elsevier Inc.

  17. 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.

  18. 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. Copyright © 2015. Published by Elsevier GmbH.

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

    International Nuclear Information System (INIS)

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

    2014-01-01

    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

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

    Science.gov (United States)

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

    2014-11-01

    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. 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.

  1. Adult phantoms as function of body mass, height and posture by using caucasian anthropomorphic statistics

    International Nuclear Information System (INIS)

    Kramer, Richard; Cassola, Vagner Ferreira; Lira, Carlos Alberto Brayner de Oliveira; Khoury, Helen Jamil; Milian, Felix Mas

    2011-01-01

    The CALLDose 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 X , this paper developed adults phantoms as function of mass and height by using anthropometric data from nine of them prevailing caucasian countries

  2. Positioning of the detectors inside an anthropomorphic phantom in order to measure the effective dose at workplace

    International Nuclear Information System (INIS)

    Furstoss, C.; Menard, S.

    2006-01-01

    Passive and active dosimeters worn on the trunk by the workers exposed to radiation fields at their workplaces measure the personal dose equivalent Hp(10), which was introduced by ICRP 60 to provide an appropriate estimate of the protection quantity: the effective dose E. However, the angular and energy distributions of the radiation fields encountered at workplaces can generate an over or an under-estimation of E because of the response of the dosimeters or/and because of the definition of H p(10) itself. That is why the Institute for Radiological Protection and Nuclear Safety (I.R.S.N.) is evaluating the possibility of the measurement of the effective dose E using an instrumented anthropomorphic phantom. The determination of the effective dose E in mixed neutron/photon fields requires to identify the nature and the energy distribution of the incident fields in order to apply the right radiation weighting factor to the mean absorbed doses. So electronic detectors will have to be placed on the surface and inside the phantom in order to identify the nature of the radiation field and to measure the mean absorbed dose within the organs. The positions and the technical characteristics of the detectors are determined by simulating the spatial distributions of the energy losses within organs and tissues of the phantom. The simulations are carried out with the Monte Carlo code M.C.N.P.X. using mesh tallies (virtual grid superimposed to the phantom geometry) and a mathematical model of an anthropomorphic phantom based on the specifications of Cristy and Eckerman. The processing of the first numerical results corresponding to photon irradiations in standard configurations (A.P., P.A. and L.A.T.) shows that for the following organs: the lungs, the liver, the small intestine and the brain, just one detector is enough and that this detector is not necessarily located at the center of the organ. On the other hand, the determination of the energy deposited in the red bone marrow

  3. Construction of a anthropomorphic phantom for dose measurement in hands in brachytherapy procedures; Construccion de un fantoma antropomorfico para mediciones de dosis en manos en procedimientos de braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Papp, Cinthia M., E-mail: cinthia_papp@yahoo.com.ar [Comision Nacional de Energia Atomica (IH/UNCUYO/CNEA), Mendoza (Argentina). Universidad Nacional de Cuyo. Instituto Balseiro; Ortiz, Arnulfo; Alvarez, Guillermo, E-mail: arnot@gmail.com, E-mail: galvarez@fuesmen.edu.ar [Fundacion Escuela de Medicina Nuclear (FUESMEN), Mendoza (Argentina)

    2013-11-01

    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.

  4. Effect of titanium dental implants on proton therapy delivered for head tumors: experimental validation using an anthropomorphic head phantom

    International Nuclear Information System (INIS)

    Oancea, C.; Shipulin, K.; Mytsin, G.; Molokanov, A.; Niculae, D.; Ambrožová, I.; Davídková, M.

    2017-01-01

    A dosimetric experiment was performed at the Medico-Technical Complex in the Joint Institute for Nuclear Research, Dubna, to investigate the effects of metallic dental implants in the treatment of head and neck tumours with proton therapy. The goal of the study was to evaluate the 2D dose distributions of different clinical treatment plans measured in an anthropomorphic phantom, and compare them to predictions from a treatment planning system. The anthropomorphic phantom was sliced into horizontal segments. Two grade 4 Titanium implants were inserted between 2 slices, corresponding to a maxillary area. GafChromic EBT2 films were placed between the segments containing the implants to measure the 2D delivered dose. Two different targets were designed: the first target includes the dental implants in the isocentre, and in the second target, the proton beam is delivered through the implants, which are located at the entrance region of the Bragg curve. The experimental results were compared to the treatment plans made using our custom 3D Treatment Planning System, named RayTreat. To quantitatively determine differences in the isodose distributions (measured and calculated), the gamma index (3 mm, 3%) was calculated for each target for the matrix value in the region of high isodose (> 90%): for the experimental setup, which includes the implants in the SOBP region, the result obtained was 84.3%. When the implants were localised in the entrance region of the Bragg curve, the result obtained was 86.4%. In conclusion, the uncertainties introduced by the clinically planned dose distribution are beyond reasonable limits. The linear energy transfer spectra in close proximity to the implants were investigated using solid state nuclear track detectors (TED). Scattered particles outside the target were detected.

  5. Effect of titanium dental implants on proton therapy delivered for head tumors: experimental validation using an anthropomorphic head phantom

    Science.gov (United States)

    Oancea, C.; Shipulin, K.; Mytsin, G.; Molokanov, A.; Niculae, D.; Ambrožová, I.; Davídková, M.

    2017-03-01

    A dosimetric experiment was performed at the Medico-Technical Complex in the Joint Institute for Nuclear Research, Dubna, to investigate the effects of metallic dental implants in the treatment of head and neck tumours with proton therapy. The goal of the study was to evaluate the 2D dose distributions of different clinical treatment plans measured in an anthropomorphic phantom, and compare them to predictions from a treatment planning system. The anthropomorphic phantom was sliced into horizontal segments. Two grade 4 Titanium implants were inserted between 2 slices, corresponding to a maxillary area. GafChromic EBT2 films were placed between the segments containing the implants to measure the 2D delivered dose. Two different targets were designed: the first target includes the dental implants in the isocentre, and in the second target, the proton beam is delivered through the implants, which are located at the entrance region of the Bragg curve. The experimental results were compared to the treatment plans made using our custom 3D Treatment Planning System, named RayTreat. To quantitatively determine differences in the isodose distributions (measured and calculated), the gamma index (3 mm, 3%) was calculated for each target for the matrix value in the region of high isodose (> 90%): for the experimental setup, which includes the implants in the SOBP region, the result obtained was 84.3%. When the implants were localised in the entrance region of the Bragg curve, the result obtained was 86.4%. In conclusion, the uncertainties introduced by the clinically planned dose distribution are beyond reasonable limits. The linear energy transfer spectra in close proximity to the implants were investigated using solid state nuclear track detectors (TED). Scattered particles outside the target were detected.

  6. Development of an Anthropomorphic Breast Phantom for Combined PET, B-Mode Ultrasound and Elastographic Imaging

    CERN Document Server

    Dang, J; Tavernier, S; Lasaygues, P; Mensah, S; Zhang, D C; Auffray, E; Frisch, B; Varela, J; Wan, M X; Felix, N

    2011-01-01

    Combining the advantages of different imaging modalities leads to improved clinical results. For example, ultrasound provides good real-time structural information without any radiation and PET provides sensitive functional information. For the ongoing ClearPEM-Sonic project combining ultrasound and PET for breast imaging, we developed a dual-modality PET/Ultrasound (US) phantom. The phantom reproduces the acoustic and elastic properties of human breast tissue and allows labeling the different tissues in the phantom with different concentrations of FDG. The phantom was imaged with a whole-body PET/CT and with the Supersonic Imagine Aixplorer system. This system allows both B-mode US and shear wave elastographic imaging. US elastography is a new imaging method for displaying the tissue elasticity distribution. It was shown to be useful in breast imaging. We also tested the phantom with static elastography. A 6D magnetic positioning system allows fusing the images obtained with the two modalities. ClearPEM-Soni...

  7. Solid anthropomorphic infant whole-body DXA phantom: design, evaluation, and multisite testing.

    Science.gov (United States)

    Shypailo, Roman J; Ellis, Kenneth J

    2013-11-01

    Dual-energy X-ray absorptiometry (DXA) requires phantoms for quality control and cross-calibration. No commercially available phantoms are designed specifically for whole-body scanning of infants. We fabricated a phantom closely matching a 7-kg human infant in body habitus using polyvinyl chloride (PVC), nylon mix, and polyethylene for bone, lean tissue, and fat, respectively, for evaluating the comparability of instruments used in studies on infant body composition. We scanned the phantom multiple times for short- and long-term repeatability and then shipped it to six other sites for comparison scans. All instruments were Hologic Delphi or Discovery models. Scan analyses were in-house procedures (Hologic V12.1). Short- and long-term results were not significantly different. Nylon mix underrepresented expected lean mass values by 5%, PVC underrepresented bone by 12%, and polyethylene overrepresented fat by 30%. Precision values were as follows: lean mass ≈ 3%; bone ≈ 3.5%; and fat = 5.5-7.5%. Instruments differed significantly for bone mineral content and density results in most instances. Three instruments differed in fat and lean mass. The two Hologic models differed significantly in all compartments except bone density. The phantom design came close to emulating bone, lean tissue, and fat and showed good reproducibility. Significant differences among various DXA instruments highlight the necessity of cross-calibration for any multicenter studies.

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

    International Nuclear Information System (INIS)

    Mukhlisin; Pawiro, S A

    2016-01-01

    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. (paper)

  9. Accuracy of fully automated, quantitative, volumetric measurement of the amount of fibroglandular breast tissue using MRI: correlation with anthropomorphic breast phantoms.

    Science.gov (United States)

    Wengert, Georg J; Pinker, Katja; Helbich, Thomas H; Vogl, Wolf-Dieter; Spijker, Sylvia M; Bickel, Hubert; Polanec, Stephan H; Baltzer, Pascal A

    2017-06-01

    To demonstrate the accuracy of fully automated, quantitative, volumetric measurement of the amount of fibroglandular breast tissue (FGT), using MRI, and to investigate the impact of different MRI sequences using anthropomorphic breast phantoms as the ground truth. In this study, 10 anthropomorphic breast phantoms that consisted of different known fractions of adipose and protein tissue, which closely resembled normal breast parenchyma, were developed. Anthropomorphic breast phantoms were imaged with a 1.5 T unit (Siemens, Avantofit) using an 18-channel breast coil. The sequence protocol consisted of an isotropic Dixon sequence (Di), an anisotropic Dixon sequence (Da), and T 1 3D FLASH sequences with and without fat saturation (T1). Fully automated, quantitative, volumetric measurement of FGT for all anthropomorphic phantoms and sequences was performed and correlated with the amounts of fatty and protein components in the phantoms as the ground truth. Fully automated, quantitative, volumetric measurements of FGT with MRI for all sequences ranged from 5.86 to 61.05% (mean 33.36%). The isotropic Dixon sequence yielded the highest accuracy (median 0.51%-0.78%) and precision (median range 0.19%) compared with anisotropic Dixon (median 1.92%-2.09%; median range 0.55%) and T 1 -weighted sequences (median 2.54%-2.46%; median range 0.82%). All sequences yielded good correlation with the FGT content of the anthropomorphic phantoms. The best correlation of FGT measurements was identified for Dixon sequences (Di, R 2  = 0.999; Da, R 2  = 0.998) compared with conventional T 1 -weighted sequences (R 2  = 0.971). MRI yields accurate, fully automated, quantitative, volumetric measurements of FGT, an increasingly important and sensitive imaging biomarker for breast cancer risk. Compared with conventional T 1 sequences, Dixon-type sequences show the highest correlation and reproducibility for automated, quantitative, volumetric FGT measurements using anthropomorphic breast

  10. A Simulation Study on Patient Setup Errors in External Beam Radiotherapy Using an Anthropomorphic 4D Phantom

    Directory of Open Access Journals (Sweden)

    Payam Samadi Miandoab

    2016-12-01

    Full Text Available Introduction Patient set-up optimization is required in radiotherapy to fill the accuracy gap between personalized treatment planning and uncertainties in the irradiation set-up. In this study, we aimed to develop a new method based on neural network to estimate patient geometrical setup using 4-dimensional (4D XCAT anthropomorphic phantom. Materials and Methods To access 4D modeling of motion of dynamic organs, a phantom employs non-uniform rational B-splines (NURBS-based Cardiac-Torso method with spline-based model to generate 4D computed tomography (CT images. First, to generate all the possible roto-translation positions, the 4D CT images were imported to Medical Image Data Examiner (AMIDE. Then, for automatic, real time verification of geometrical setup, an artificial neural network (ANN was proposed to estimate patient displacement, using training sets. Moreover, three external motion markers were synchronized with a patient couch position as reference points. In addition, the technique was validated through simulated activities by using reference 4D CT data acquired from five patients. Results The results indicated that patient geometrical set-up is highly depended on the comprehensiveness of training set. By using ANN model, the average patient setup error in XCAT phantom was reduced from 17.26 mm to 0.50 mm. In addition, in the five real patients, these average errors were decreased from 18.26 mm to 1.48 mm various breathing phases ranging from inhalation to exhalation were taken into account for patient setup. Uncertainty error assessment and different setup errors were obtained from each respiration phase. Conclusion This study proposed a new method for alignment of patient setup error using ANN model. Additionally, our correlation model (ANN could estimate true patient position with less error.

  11. Numerical absorbed dose distributions inside principal organs of a mathematical anthropomorphic phantom irradiated by monoenergetic photon fields

    International Nuclear Information System (INIS)

    Furstoss, C.; Menard, S.

    2005-01-01

    Full text: Personnel can be exposed to photon or mixed (neutrons and photons) radiations at workplaces for various activities (nuclear fuel cycle, medical sector, research... ). The passive and active personal dosimeters worn on the trunk evaluate the personal dose equivalent Hp(10), defined by ICRP 601 to be an estimator of the effective dose E. However, the angular and energy distributions of the radiations encountered could generate an over or under-estimation of the protection quantity E because of the response of the dosimeters or/and because of the definition of Hp(10) itself. The Institute of Radiological Protection and Nuclear Safety (IRSN) is evaluating the possibility of the measurement of the effective dose E using an instrumented anthropomorphic phantom at workplaces. Such an instrument would allow the control of the suitability of the radiological protection instrumentation used at workplaces for radiation fields which can appreciably differ from the reference ISO radiation fields used to calibrate dosimeters. The objectives of this study are to determine key positions for the future detectors inside and on the phantom, as well as their needed technical characteristics. The simulations of the organ absorbed dose distributions performed using the Monte Carlo code MCNPX2 and the MIRD phantom3 model will allow the determination of the detector locations. This paper will present the first numerical results obtained for monoenergetic parallel photon fields. The effective doses E calculated in an energy range from 15 keV to 10 MeV will be presented and compared with the results of M. Zankl et al., published in the GSF report Bericht 8/974. (author)

  12. Activation rate uniformity in a bilateral IVNAA facility for two anthropomorphic phantoms

    Directory of Open Access Journals (Sweden)

    Miri Hakimabad Hashem

    2010-01-01

    Full Text Available Activation rate uniformity is the first property which is considered in the design of a prompt γ-ray in vivo neutron activation analysis facility. Preliminary studies on the activation rate distribution in the body can be done by use of Monte Carlo codes, such as the MCNP. In this paper, different bilateral configurations of an IVNAA system are considered in order to improve the activation rate uniformity in a water phantom measuring 32 cm x 100 cm x 16 cm. In the best case, uniformity parameters are U = 1.003 and R = 1.67, with the mean activation rate of 1.85×10-6 cm-3. In more accurate calculations, the water phantom is replaced by a body model. The model in question is a 5 year-old ORNL phantom filled with just soft tissue. For uniformity studies, the internal organs are not simulated. Finally, uniformity parameters in this case are U = 1.005 and R = 12.2.

  13. Radiation dose evaluation in 64-slice CT examinations with adult and paediatric anthropomorphic phantoms.

    Science.gov (United States)

    Fujii, K; Aoyama, T; Yamauchi-Kawaura, C; Koyama, S; Yamauchi, M; Ko, S; Akahane, K; Nishizawa, K

    2009-12-01

    The objective of this study was to evaluate the organ dose and effective dose to patients undergoing routine adult and paediatric CT examinations with 64-slice CT scanners and to compare the doses with those from 4-, 8- and 16-multislice CT scanners. Patient doses were measured with small (effective doses were computed. For the adult phantom, organ doses (for organs within the scan range) and effective doses were 8-35 mGy and 7-18 mSv, respectively, for chest CT, and 12-33 mGy and 10-21 mSv, respectively, for abdominopelvic CT. For the paediatric phantom, organ and effective doses were 4-17 mGy and 3-7 mSv, respectively, for chest CT, and 5-14 mGy and 3-9 mSv, respectively, for abdominopelvic CT. Doses to organs at the boundaries of the scan length were higher for 64-slice CT scanners using large beam widths and/or a large pitch because of the larger extent of over-ranging. The CT dose index (CTDI(vol)), dose-length product (DLP) and the effective dose values using 64-slice CT for the adult and paediatric phantoms were the same as those obtained using 4-, 8- and 16-slice CT. Conversion factors of DLP to the effective dose by International Commission on Radiological Protection 103 were 0.024 mSvmGy(-1)cm(-1) and 0.019 mSvmGy(-1)cm(-1) for adult chest and abdominopelvic CT scans, respectively.

  14. 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.

  15. Radiation dose evaluation in head and neck MDCT examinations with a 6-year-old child anthropomorphic phantom.

    Science.gov (United States)

    Yamauchi-Kawaura, Chiyo; Fujii, Keisuke; Aoyama, Takahiko; Koyama, Shuji; Yamauchi, Masato

    2010-07-01

    CT examinations of the head and neck are the most commonly performed CT studies in children, raising concern about radiation dose and their risks to children. The purpose of this study was to clarify radiation dose levels for children of 6 years of age undergoing head and neck multidetector CT (MDCT) examinations. Radiation doses were measured with small-sized silicon-photodiode dosimeters that were implanted at various tissue and organ positions within a standard 6-year-old anthropomorphic phantom. Organ and effective doses of brain CT were evaluated for 19 protocols in nine hospitals on various (2-320 detector rows) MDCT scanners. The maximum value of mean organ dose in brain CT was 34.3 mGy for brain. Maximum values of mean doses for the radiosensitive lens and thyroid were 32.7 mGy for lens in brain CT and 17.2 mGy for thyroid in neck CT. seventy-fifth percentile of effective dose distribution in brain CT was approximately the same as the diagnostic reference level (DRL) in the 2003 UK survey. The results of this study would encourage revision of MDCT protocols in pediatric head and neck CT examinations for dose reduction and protocol standardization.

  16. Radiation dose evaluation in head and neck MDCT examinations with a 6-year-old child anthropomorphic phantom

    Energy Technology Data Exchange (ETDEWEB)

    Yamauchi-Kawaura, Chiyo; Aoyama, Takahiko; Koyama, Shuji [Nagoya University, Daikominami, Higashi-ku, School of Health Sciences, Nagoya (Japan); Fujii, Keisuke [Nagoya University, Daikominami, Higashi-ku, School of Health Sciences, Nagoya (Japan); National Institute of Radiological Sciences, Section of Radiological Protection, Chiba (Japan); Yamauchi, Masato [Aichi Medical University Hospital, Division of Radiology, Nagakute-cho, Aichi-gun, Aichi (Japan)

    2010-07-15

    CT examinations of the head and neck are the most commonly performed CT studies in children, raising concern about radiation dose and their risks to children. The purpose of this study was to clarify radiation dose levels for children of 6 years of age undergoing head and neck multidetector CT (MDCT) examinations. Radiation doses were measured with small-sized silicon-photodiode dosimeters that were implanted at various tissue and organ positions within a standard 6-year-old anthropomorphic phantom. Organ and effective doses of brain CT were evaluated for 19 protocols in nine hospitals on various (2-320 detector rows) MDCT scanners. The maximum value of mean organ dose in brain CT was 34.3 mGy for brain. Maximum values of mean doses for the radiosensitive lens and thyroid were 32.7 mGy for lens in brain CT and 17.2 mGy for thyroid in neck CT. seventy-fifth percentile of effective dose distribution in brain CT was approximately the same as the diagnostic reference level (DRL) in the 2003 UK survey. The results of this study would encourage revision of MDCT protocols in pediatric head and neck CT examinations for dose reduction and protocol standardization. (orig.)

  17. 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)

    Bruhov, R.E.; Finkel, F.V.

    2013-01-01

    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 90 Sr 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 222 Rn decay in the respiratory tract, 241 Am, 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

  18. Pilot Investigation into the Use of an Anthropomorphic Breast Sonography Phantom as a Training and Assessment Tool.

    Science.gov (United States)

    Browne, Jacinta E; Cannon, Louise M; McDermott, Ronan; Ryan, Max; Fagan, Andrew J

    2017-11-01

    A device for the training and quantitative assessment of the competency of trainee radiologists in the technically challenging area of breast sonography was developed and evaluated. Currently, suitable commercially available devices are lacking, and there is a growing realization that the reliance on direct exposure to patients for learning may not represent best practice from either the trainees' or patients' perspective. Three devices (PI, PII and PIII) were designed to produce very realistic sonographic images of breast morphology with a range of embedded pathologies. The pilot evaluation used a case study research design to evaluate the role of the anthropomorphic breast sonography training device in training and assessment in a clinical environment. Through the case study, it was possible to evaluate the process and relationships when using this type of training intervention for a small group of radiology resident trainees. The investigation involved a baseline assessment of trainees' (n = 4) ability to detect and characterize all lesions in PI, followed by a 4-wk training period on PII and a post-training assessment using PIII. The evaluation revealed an improvement of 30% ± 8% in the trainee's performance from pre- to post-training. It was expected that the performance of the trainees would improve as the training phantom described in this study aligns with the learning theory of constructivism and fits the ideal specifications of a medical training device in terms of its realism and facilitation of self-directed learning and deliberate practice of the trainees. The device provides a useful platform upon which training and assessment can be facilitated. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  19. Image quality for five modern chest radiography techniques: a modified FROC study with an anthropomorphic chest phantom

    International Nuclear Information System (INIS)

    Maansson, L.G.; Lanhede, B.; Kheddache, S.; Tylen, U.

    1999-01-01

    The purpose of the study was to compare the image quality for one conventional and four digital chest radiography techniques. Three storage phosphor systems, one selenium drum system, and one film-screen system were compared using a modified receiver-operating-characteristics method. Simulated pathology was randomly positioned over the parenchymal regions and the mediastinum of an anthropomorphic phantom. Eight observers (four chest radiologists, one specialist in general radiology, one hospital physicist, and two radiographers) evaluated 60 images for each technique. The selenium drum system (Philips, Eindhoven, The Netherlands) rated best for the detection of parenchymal nodules. Together with the storage phosphor system of generation IIIN (Philips/Fuji), the selenium drum system also rated best for detection of thin linear structures. The storage phosphor system of generation V (Fuji) rated best for the detection of mediastinal nodules. The first generation of the storage phosphor system from Agfa (Mortsel, Belgium) rated worst for the detection of parenchymal nodules and thin linear structures. These differences were significant (p < 0.0001). Averaging the results for all test objects, the selenium drum system and the storage phosphor system of generation V were significantly better than the other systems tested. The film/screen system performed significantly better than the first-generation storage phosphor system from Agfa, equal to the generation IIIN storage phosphor system (Philips/Fuji) and significantly worse than the selenium drum system (Philips) and the generation-V storage phosphor system (Fuji). The conclusion is therefore that the image quality of selenium-based digital technique and of the more recent generations of storage phosphor systems is superior to both conventional technique and storage phosphor systems using image plates of older types. (orig.)

  20. The Effect of Contrast Material on Radiation Dose at CT: Part I. Incorporation of Contrast Material Dynamics in Anthropomorphic Phantoms.

    Science.gov (United States)

    Sahbaee, Pooyan; Segars, W Paul; Marin, Daniele; Nelson, Rendon C; Samei, Ehsan

    2017-06-01

    Purpose To develop a method to incorporate the propagation of contrast material into computational anthropomorphic phantoms for estimation of organ dose at computed tomography (CT). Materials and Methods A patient-specific physiologically based pharmacokinetic (PBPK) model of the human cardiovascular system was incorporated into 58 extended cardiac-torso (XCAT) patient phantoms. The PBPK model comprised compartmental models of vessels and organs unique to each XCAT model. For typical injection protocols, the dynamics of the contrast material in the body were described according to a series of patient-specific iodine mass-balance differential equations, the solutions to which provided the contrast material concentration time curves for each compartment. Each organ was assigned to a corresponding time-varying iodinated contrast agent to create the contrast material-enhanced five-dimensional XCAT models, in which the fifth dimension represents the dynamics of contrast material. To validate the accuracy of the models, simulated aortic and hepatic contrast-enhancement results throughout the models were compared with previously published clinical data by using the percentage of discrepancy in the mean, time to 90% peak, peak value, and slope of enhancement in a paired t test at the 95% significance level. Results The PBPK model allowed effective prediction of the time-varying concentration curves of various contrast material administrations in each organ for different patient models. The contrast-enhancement results were in agreement with results of previously published clinical data, with mean percentage, time to 90% peak, peak value, and slope of less than 10% (P > .74), 4%, 7%, and 14% for uniphasic and 12% (P > .56), 4%, 12%, and 14% for biphasic injection protocols, respectively. The exception was hepatic enhancement results calculated for a uniphasic injection protocol for which the discrepancy was less than 25%. Conclusion A technique to model the propagation of

  1. Fabrication of an anthropomorphous phantom equipped with sensors to assess the efficient dose at workstations submitted to photonic fields: experimental study

    International Nuclear Information System (INIS)

    Darreon, J.

    2009-12-01

    The efficient dose is a reference value in radioprotection. It allows the harmfulness of ionizing radiations received by organs and tissues to be assessed. It is used on a legal basis but is not directly measurable. This research thesis reports a practical feasibility study of an anthropomorphous dummy or phantom equipped with sensors to assess the efficient dose from selective measurements. A first part deals with the dose measurement system, i.e. the sensors which will be embedded in the phantom. The second part, based on a simulation performed with a Monte Carlo code, reports the study of the efficient dose assessment accuracies for different irradiation configurations which could be obtained with this measurement instrument. The author shows that the estimation accuracy can be improved by modifying the sensor locations with respect to doses deposited in future reference phantoms of the International Commission on Radiological Protection

  2. 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

  3. SU-F-T-168: Development and Implementation of An Anthropomorphic Head & Neck Phantom for the Assessment of Proton Therapy Treatment Procedures

    Energy Technology Data Exchange (ETDEWEB)

    Branco, D; Taylor, P; Frank, S; Li, H; Zhang, X; Mehrens, H; Guindani, M; Followill, D [UT MD Anderson Cancer Center, Houston, TX (United States)

    2016-06-15

    Purpose: To design a Head and Neck (H&N) anthropomorphic QA phantom that the Imaging and Radiation Oncology Core Houston (IROC-H) can use to verify the quality of intensity modulated proton therapy (IMPT) H&N treatments for institutions participating in NCI clinical trials. Methods: The phantom was created to serve as a remote auditing tool for IROC-H to evaluate an institution’s IMPT planning and delivery abilities. The design was based on the composition, size, and geometry of a generalized oropharyngeal tumor and contains critical structures (parotids and spinal cord). Radiochromic film in the axial and sagittal planes and thermoluminescent dosimeters (TLD)-100 capsules were embedded in the phantom and used to perform the dose delivery evaluation. A CT simulation was used to create a passive scatter and a spot scanning treatment plan with typical clinical constraints for H&N cancer. The IMPT plan was approved by a radiation oncologist and the phantom was irradiated multiple times. The measured dose distribution using a 7%/4mm gamma analysis (85% of pixels passing) and point doses were compared with the treatment planning system calculations. Results: The designed phantom could not achieve the target dose prescription and organ at risk dose constraints with the passive scatter treatment plan. The target prescription dose could be met but not the parotid dose constraint. The average TLD point dose ratio in the target was 0.975, well within the 5% acceptance criterion. The dose distribution analysis using various acceptance criteria, 5%/4mm, 5%/3mm, 7%/4mm and 7%/5mm, had average pixel passing rates of 85.9%, 81.8%, 89.6% and 91.6%, and respectively. Conclusion: An anthropomorphic IMPT H&N phantom was designed that can assess the dose delivery of proton sites wishing to participate in clinical trials using a 5% TLD dose and 7%/4mm gamma analysis acceptance criteria.

  4. 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)

    Furstoss, Ch.

    2006-11-01

    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)

  5. 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

  6. Radiation dose evaluation in tomosynthesis and C-arm cone-beam CT examinations with an anthropomorphic phantom.

    Science.gov (United States)

    Koyama, Shuji; Aoyama, Takahiko; Oda, Nobuhiro; Yamauchi-Kawaura, Chiyo

    2010-08-01

    The objective of this study was to evaluate organ dose and the effective dose to patients undergoing tomosynthesis (TS) and C-arm cone-beam computed tomography (CBCT) examinations and to compare the doses to those in multidetector CT (MDCT) scans. Patient doses were measured with small sized silicon-photodiode dosimeters, 48 in number, which were implanted at various tissue and organ positions within an anthropomorphic phantom. Output signals from photodiode dosimeters were read out on a personal computer, from which organ and effective doses were computed. The doses in head, chest, abdomen, and hip-joint TS, and in head and abdomen C-arm CBCT were evaluated for routine protocols on Shimadzu TS and C-arm CBCT systems, and the doses in MDCT with the same scan regions as in TS and CBCT were on Toshiba 64-detector-row CT scanners. In TS examination of the head, chest, abdomen, and hip-joint, organ doses for organs within scan ranges were 1-4 mGy, and effective doses were 0.07 mSv for the head scan and around 1 mSv for other scans. In C-arm CBCT examinations of the head and abdomen, organ doses within scan range were 2-37 mGy, and effective doses were 1.2 mSv for the head scan and 4-5 mSv for abdominal scans. Effective doses in TS examinations were approximately a factor of 10 lower, while the doses in CBCT examinations were nearly the same level, compared to the doses in the corresponding MDCT examinations. TS examinations with low doses and excellent resolutions in coronal images compared to recent MDCT would widely be used in tomographic examinations of the chest, abdomen, pelvis, skeletal-joints, and knee instead of MDCT examinations with significantly high doses. Since patient dose in C-arm CBCT was nearly the same level as that in recent MDCT, the same consideration for high radiation dose would be required for the use of CBCT.

  7. 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)

    Jang, S.; Jaszczak, R.J.; Duke Univ. Medical Center, Durham, NC; Gilland, D.R.; Turkington, T.G.; Coleman, R.E.; Tsui, B.M.W.; Metz, C.E.

    1998-01-01

    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

  8. Investigation of the characteristics of Automatic Exposure Control (AEC) of a Computed Tomography (CT) scanner by utilising cylindrical and anthropomorphic phantoms

    Science.gov (United States)

    Rulaidi, W. E. P.; Huri, M. S. N.; Ng, K. H.

    2017-05-01

    One method to optimise the use of x-rays in CT and hence a reduction in patient dose is the application of automatic exposure control (AEC). This study measured the effective mAs, image noise and volume CT dose index (CTDIvol) as the result of changing the AEC index on a Siemens Somatom Definition 64 slices dual source CT scanner. The scans were performed on four phantoms of different geometries, namely the 16 and 32 cm cylindrical CTDI phantoms and two anthropomorphic phantoms, RANDO (20 cm effective diameter) and ATOM (19.8 cm effective diameter). Results showed that the effective mAs increased with increasing tube potential (kVp) and Quality Reference mAs (QRM), therefore increasing CTDIvol while reducing image noise. Meanwhile, no changes of radiation dose and image noise were observed when the pitch was increased. However, for the largest phantom (32 cm effective diameter), a constant effective mAs was found between 120 and 140 kVp. The same trend was also found with increasing QRM from 300 mAs to 400 mAs suggesting a certain limitation of the AEC has been reached. In conclusion, this study showed that AEC is affected by kVp and QRM but not by pitch selection. Further work is required to quantify the characteristics of the AEC system in relation to the mentioned parameters for better optimisation.

  9. Variability in Heart-to-Mediastinum Ratio from Planar123I-MIBG Images of a Thorax Phantom for 6 Common γ-Camera Models.

    Science.gov (United States)

    Owenius, Rikard; Zanette, Michelle; Cella, Patrick

    2017-12-01

    A heart-to-mediastinum (H/M) ratio of 1.6 or greater on planar 123 I-iobenguane ( 123 I-MIBG) images identifies heart failure patients at low risk of experiencing an adverse cardiac event. This phase-4 study used standardized phantoms to assess the intercamera, intracamera, and interhead variability in H/M ratio determinations from planar cardiac 123 I-MIBG imaging using commercially available, dual-head γ-cameras. Methods: A fillable thorax phantom was developed to simulate the typical uptake of 123 I-MIBG. The phantom had a nominal H/M ratio of 1.6 on the reference camera. Commercial cameras used in the study were dual-head and capable of 90° configuration for cardiac imaging. The target sample size was 8 units (examples) per camera model. Two imaging technologists independently analyzed planar images of simulated 123 I-MIBG uptake from the thorax phantom. H/M was the ratio of the average counts per pixel of the heart and mediastinum regions of interest. The primary endpoint, intercamera variability in H/M ratio from head 1, was determined for each camera model via comparison with the H/M ratio on the reference camera. Only cameras with at least 8 units tested ( n ≥ 8) were included in the primary analysis. Intracamera and interhead variability in the H/M ratio were also evaluated. Results: Nine camera models were studied. The mean H/M ratio ranged from 1.342 to 1.677. The primary analysis (6 camera models) using a mixed-model, repeated-measures analysis showed no significant difference in H/M ratio between any camera model and the reference camera. Intracamera variability (head 1) in the H/M ratio among camera models with 8 units or more was high, with SDs ranging from 0.0455 to 0.1193. Interhead variability was low (SDs of the interhead difference, 0.017-0.074). Conclusion: Commonly used γ-cameras produced H/M ratios from simulated 123 I-MIBG phantom images that were not significantly different from those on the reference camera. This finding indicates

  10. 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)

    Morita, Yasuhiko; Indou, Hiroko; Honda Eiichi

    2002-01-01

    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)

  11. 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)

    Matsunobu, Y; Shiotsuki, K; Morishita, J

    2015-01-01

    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

  12. 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.

  13. 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)

    Liu Xinming; Lai Chaojen; Whitman, Gary J.; Geiser, William R.; Shen Youtao; Yi Ying; Shaw, Chris C.

    2011-01-01

    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

  14. Evaluation of neutron doses received at different organs in radiotherapy treatments using the UAB PADC based dosemeters in an anthropomorphic phantom

    Energy Technology Data Exchange (ETDEWEB)

    Domingo, C., E-mail: carles.domingo@uab.ca [Grup de Fisica de les Radiacions, Departament de Fisica, Edifici C, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); Garcia-Fuste, M.J.; Morales, E.; Amgarou, K.; Castelo, J. [Grup de Fisica de les Radiacions, Departament de Fisica, Edifici C, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); Sanchez-Doblado, F. [Hospital Universitario Virgen Macarena, Servicio de Radiofisica, Sevilla (Spain); Departamento de Fisiologia Medica y Biofisica, Facultad de Medicina, Universidad de Sevilla (Spain)

    2009-10-15

    The NEUTOR project was set up to study radiotherapy patient exposures to the neutrons produced around the LINAC accelerator head by photon radiation above approx8 MeV. These neutrons may reach the patient directly, or they may interact with the surrounding materials until they become thermalised, scattering all over the treatment room and affecting the patient as well. A miniaturised version of the UAB PADC based neutron dosemeter is used, together with thermoluminescence Li-6/Li-7 pairs, in several positions inside an anthropomorphic female phantom to determine doses received by the patient at several organs or tissues. Irradiations were made at a 15 MV LINAC (Hospital Universitario Virgen de la Macarena, Sevilla, Spain), an 18 MV LINAC (Hospital General Universitario de Valencia, Spain) and a 23 MV LINAC (Universitaetsklinikum Heidelberg, Germany). Preliminary patient dose maps obtained from the UAB PADC dosemeter measurements (considering an average calibration factor for all neutron energies) are reported in this work.

  15. 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)

    Greuter, Marcel J.W.; Dorgelo, Joost; Tukker, Wim G.J.; Oudkerk, Matthijs

    2005-01-01

    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.)

  16. 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.

  17. 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.

  18. Application of Monte Carlo calculations to calibration of anthropomorphic phantoms used for activity assessment of actinides in lungs.

    Science.gov (United States)

    Franck, D; Borissov, N; de Carlan, L; Pierrat, N; Genicot, J L; Etherington, G

    2003-01-01

    This paper reports on a new utility for development of computational phantoms for Monte Carlo calculations and data analysis for in vivo measurements of radionuclides deposited in tissues. The individual parameters of each worker can be acquired for an exact geometric representation of his or her anatomy, which is particularly important for low-energy gamma ray emitting sources such as thorium, uranium, plutonium and other actinides. The software discussed here enables automatic creation of an MCNP input data file based on computed tomography (CT) scanning data. The utility was first tested for low- and medium-energy actinide emitters on Livermore phantoms, the mannequins generally used for lung counting, in order to compare the results of simulation and measurement. From these results, the utility's ability to study uncertainties in in vivo calibration were investigated. Calculations and comparison with the experimental data are presented and discussed in this paper.

  19. 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.

  20. 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)

    Shaw, D.J.; Crawshaw, I.; Rimmer, S.D.

    2013-01-01

    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 kV p ) 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 kV p relative to 109 kV p , 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

  1. Comparison of airway diameter measurements from an anthropomorphic airway tree phantom using hyperpolarized 3He MRI and high-resolution computed tomography.

    Science.gov (United States)

    Tzeng, Yang-Sheng; Hoffman, Eric; Cook-Granroth, Janice; Maurer, Rie; Shah, Niral; Mansour, Joey; Tschirren, Juerg; Albert, Mitchell

    2007-09-01

    An anthropomorphic airway tree phantom was imaged with both hyperpolarized (HP) 3He MRI using a dynamic projection scan and computed tomography (CT). Airway diameter measurements from the HP 3He MR images obtained using a newly developed model-based algorithm were compared against their corresponding CT values quantified with a well-established method. Of the 45 airway segments that could be evaluated with CT, only 14 airway segments (31%) could be evaluated using HP 3He MRI. No airway segments smaller than approximately 4 mm in diameter and distal to the fourth generation were adequate for analysis in MRI. For the 14 airway segments measured, only two airway segments yielded a non-equivalent comparison between the two imaging modalities, while eight more had inconclusive comparison results, leaving only four airway segments (29%) that satisfied the designed equivalence criteria. Some of the potential problems in airway diameter quantification described in the formulation of the model-based algorithm were observed in this study. These results suggest that dynamic projection HP 3He MRI may have limited utility for measuring airway segment diameters, particularly those of the central airways. Copyright (c) 2007 Wiley-Liss, Inc.

  2. 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)

    Bandeira, Caroline K.; Vieira, Michele P.M.M.; Felix, Jose E.R.

    2014-01-01

    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)

  3. Quantifying the effects of iodine contrast media on standardised uptake values of FDG PET/CT images: an anthropomorphic phantom study.

    Science.gov (United States)

    Abdul Razak, Hairil Rashmizal; Nordin, Abdul Jalil; Ackerly, Trevor; Van Every, Bruce; Martin, Ruth; Geso, Moshi

    2011-09-01

    This study aimed to quantify the amount of change in Standardised Uptake Values (SUVs) of PET/CT images by simulating the set-up as closely as possible to the actual patient scanning. The experiments were conducted using an anthropomorphic phantom, which contained an amount of radioactivity in the form of Fluorodeoxyglucose (FDG) in a primary plastic test tube and one litre saline bags, including the insertion of bony structures and another two test tubes containing different concentrations of iodine contrast media. Standard scanning protocols were employed for the PET/CT image acquisition. The highest absolute differences in the SUVmax and SUVmean values of the saline bags were found to be about 0.2 and 0.4, respectively. The primary test tube showed the largest change of 1.5 in both SUVs; SUV max and SUVmean. However, none of these changes were found to be statistically significant. The clinical literature also contains no evidence to suggest that the changes of this magnitude would change the final diagnosis. Based on these preliminary data, we propose that iodine contrast media can be used during the CT scan of PET/CT imaging, without significantly affecting the diagnostic quality of this integrated imaging modality.

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

    International Nuclear Information System (INIS)

    Garcia, Paulo L.; Silva, Leonardo P.; Santos, Maira R.; Trindade, Cassia; Martins, Lais P.; Batista, Delano V.S.; Alves, Victor G.

    2012-01-01

    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. Design construction and testing of a human abdomen phantom (anthropomorphic) for in-vivo dosimetry in radiology

    International Nuclear Information System (INIS)

    Addison, E.C.K.; Andam, A.B.; Nani, E.K.; Dogbe, R.

    2007-01-01

    Using direct measurement, we investigated entrance surface doses of patients for routine radiographs in attempt to develop evaluation methods of patient dose in order to establish the guidance level in Ghana. To date, patient doses have been evaluated by calculation based on radiographic conditions, or model experiments using phantoms, also based on several assumptions. Direct measurement of patient dose is difficult to perform in many patients due to its time requirement, level of expertise required and difficulty in providing an explanation of the procedure to the patient. However, such direct measurement is essential since it incorporates all aspects of radiography from the radiographic equipment used, to the actual conditions of each patient without assumption. In this study, we examined the need for introducing the guidance level, controversial points in the calculation method for patient dose evaluation, evaluation accuracy required for introducing the guidance level, and necessity for a standardized method. The variation between measured and calculated doses range between -4.8 to +29.3 per cent. Computational technique is a wide ranging and cost effective method od conducting representative patient dose estimations in plain radiography. (au)

  6. Optimisation of the body composition analyser using the gamma shield and improvement of accuracy using ORNL anthropomorphic phantoms.

    Science.gov (United States)

    Araghian, N; Rafat-Motavalli, L; Miri-Hakimabad, H

    2013-07-01

    The analysis of body elements using the prompt gamma rays neutron activation method is a very useful and highly accurate method Lone, M. A., Mughabghab, S. F. and Paviotti-Corcuera, R. Development of a database for prompt gamma-ray neutron activation analysis. Summary Report of the Second Research Coordination Meeting. IAEA Headquarters. IAEA Nuclear Data Section. INDC(NDS)-424. (2001) that has many applications in different fields such as the diagnosis of specific diseases, including certain types of cancers. To protect patients from gamma rays produced by the system, an efficient strategy is to apply a gamma shield. In this study, the gamma shield was placed in three separate positions. The influence of these positions on reducing the effective dose was examined in a 5-y-old Oak Ridge National Laboratory mathematical phantom. Other parameters considered were sensitivity and coefficient of variation (CV) of thermal neutron fluence rate. With the best configuration, the total effective dose per minute (ET) was decreased ∼52 % and the sensitivity was ∼2.03-fold higher than when no shield was present.

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

    International Nuclear Information System (INIS)

    Nogueira, Luciana B.; Campos, Tarcisio P.R.

    2013-01-01

    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)

  8. Characterization of the secondary neutron field produced during treatment of an anthropomorphic phantom with x-rays, protons and carbon ions.

    Science.gov (United States)

    Tessa, C La; Berger, T; Kaderka, R; Schardt, D; Burmeister, S; Labrenz, J; Reitz, G; Durante, M

    2014-04-21

    Short- and long-term side effects following the treatment of cancer with radiation are strongly related to the amount of dose deposited to the healthy tissue surrounding the tumor. The characterization of the radiation field outside the planned target volume is the first step for estimating health risks, such as developing a secondary radioinduced malignancy. In ion and high-energy photon treatments, the major contribution to the dose deposited in the far-out-of-field region is given by neutrons, which are produced by nuclear interaction of the primary radiation with the beam line components and the patient's body. Measurements of the secondary neutron field and its contribution to the absorbed dose and equivalent dose for different radiotherapy technologies are presented in this work. An anthropomorphic RANDO phantom was irradiated with a treatment plan designed for a simulated 5 × 2 × 5 cm³ cancer volume located in the center of the head. The experiment was repeated with 25 MV IMRT (intensity modulated radiation therapy) photons and charged particles (protons and carbon ions) delivered with both passive modulation and spot scanning in different facilities. The measurements were performed with active (silicon-scintillation) and passive (bubble, thermoluminescence ⁶LiF:Mg, Ti (TLD-600) and ⁷LiF:Mg, Ti (TLD-700)) detectors to investigate the production of neutral particles both inside and outside the phantom. These techniques provided the whole energy spectrum (E ≤ 20 MeV) and corresponding absorbed dose and dose equivalent of photo neutrons produced by x-rays, the fluence of thermal neutrons for all irradiation types and the absorbed dose deposited by neutrons with 0.8 neutrons is observed for photons and, among ions, for passively modulated beams. For the treatment with high-energy x-rays, the contribution of secondary neutrons to the dose equivalent is of the same order of magnitude as the primary radiation. In carbon therapy delivered with raster

  9. Relationships of clinical protocols and reconstruction kernels with image quality and radiation dose in a 128-slice CT scanner: Study with an anthropomorphic and water phantom

    International Nuclear Information System (INIS)

    Paul, Jijo; Krauss, B.; Banckwitz, R.; Maentele, W.; Bauer, R.W.; Vogl, T.J.

    2012-01-01

    Research highlights: ► Clinical protocol, reconstruction kernel, reconstructed slice thickness, phantom diameter or the density of material it contains directly affects the image quality of DSCT. ► Dual energy protocol shows the lowest DLP compared to all other protocols examined. ► Dual-energy fused images show excellent image quality and the noise is same as that of single- or high-pitch mode protocol images. ► Advanced CT technology improves image quality and considerably reduce radiation dose. ► An important finding is the comparatively higher DLP of the dual-source high-pitch protocol compared to other single- or dual-energy protocols. - Abstract: Purpose: The aim of this study was to explore the relationship of scanning parameters (clinical protocols), reconstruction kernels and slice thickness with image quality and radiation dose in a DSCT. Materials and methods: The chest of an anthropomorphic phantom was scanned on a DSCT scanner (Siemens Somatom Definition flash) using different clinical protocols, including single- and dual-energy modes. Four scan protocols were investigated: 1) single-source 120 kV, 110 mA s, 2) single-source 100 kV, 180 mA s, 3) high-pitch 120 kV, 130 mA s and 4) dual-energy with 100/Sn140 kV, eff.mA s 89, 76. The automatic exposure control was switched off for all the scans and the CTDIvol selected was in between 7.12 and 7.37 mGy. The raw data were reconstructed using the reconstruction kernels B31f, B80f and B70f, and slice thicknesses were 1.0 mm and 5.0 mm. Finally, the same parameters and procedures were used for the scanning of water phantom. Friedman test and Wilcoxon-Matched-Pair test were used for statistical analysis. Results: The DLP based on the given CTDIvol values showed significantly lower exposure for protocol 4, when compared to protocol 1 (percent difference 5.18%), protocol 2 (percent diff. 4.51%), and protocol 3 (percent diff. 8.81%). The highest change in Hounsfield Units was observed with dual

  10. 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)

  11. 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)

    Emigh, Brent; Gordon, Christopher L.; Falkiner, Michelle; Thomas, Karen E.; Connolly, Bairbre L.

    2013-01-01

    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-cm 2 to 4.3 x 10 -3 mSv per Gy-cm 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 protocols through the use of direct organ

  12. 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

  13. The thorax

    International Nuclear Information System (INIS)

    Higgins, C.B.

    1987-01-01

    Computed tomography (CT) is becoming increasingly important for evaluation of thoracic diseases. The clinical role of MRI requires direct comparison of its advantages with those of CT. For imaging of the thorax, MRI has some intrinsic advantages in regard to other modalities. It also has some disadvantages at present, but these may be temporary, because MRI is still an immature and rapidly developing technology. The major advantage is maximum contrast between lesions and blood vessels at all tomographic levels. On the other hand, achieving such contrast with CT requires precise coordination between delivery of the bolus of contrast materials and exposure of the CT scan; this can generally be attained only at one or a few anatomic levels. Metallic surgical clips cause a signal void on MRI but do not cause the severe streak artifacts seen on CT scans. Another advantage of MRI results from the high MRI intensity of fat. This provides high contrast between lesions and hilar or mediastinal fat. The ability to obtain MR images in multiple planes can be critical for evaluating abnormalities in some locations, such as the aorticopulmonary window and the cervicothoracic junction. Coronal and sagittal reconstructions from transverse CT scans generally have not been useful because of markedly reduced spatial resolution in the reconstructed plane

  14. The thorax

    International Nuclear Information System (INIS)

    Bragg, D.G.

    1986-01-01

    In the first section, Techniques of Examination, two articles are housed; others relate indirectly to technique and can be found in the Pulmonary-General section. The Mediastinum and Chest Wall section contains an initial article on the Mounier-Kuhn Syndrome, tracheobronchiomegaly. Two other articles describe the CT appearance of extensions of the pericardium that may mimic lymphadenopathy. Another article describes the plain film criteria for excluding aortic rupture in blunt chest trauma. The Pleura section includes an article on oleothorax, a relic from the past with which younger radiologists may not be familiar. An article from our vicinity describes the CT detection of occult pneumorthorax in patients with head trauma, extending the CT examination of the head to the thorax in this group of patients with a significant yield of unsuspected pneumothoraces. Finally, the CT look-alikes of pleural mesothelioma and asbestosis in two separate articles are included for your review. The final and largest section is subdivided into Pulmonary-General and Pulmonary-Neoplastic

  15. Evaluation of effective dose in an anthropomorphic phantom in radiological emergencies situations; Avaliacao de dose efetiva em um fantoma antropomorfico em situacoes de emergencia radiologica

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Livia K. da, E-mail: liviatelecom@hotmail.com [Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropedica, RJ (Brazil). Inst. de Ciencias Exatas. Dept. de Fisica; Ribeiro, Rosane M.; Santos, Denison de S., E-mail: liviatelecom@hotmail.com, E-mail: rosanemribeiro@oi.com.br, E-mail: santosd@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Div. de Dosimetria

    2013-07-01

    This work aims to implement the code of Monte Carlo Geant4 in a male and female phantom, ADAM and EVA, to be able to evaluate the dose in individuals who have been exposed externally to ionizing radiation sources so that in the future be made a review within the limits of validity of the terms contained in TECDOC-1162, published by the International Atomic Energy Agency (IAEA), which recommends formulas for the effective dose assessment in individuals who have been exposed to external radiation sources in various geometric configurations and for various radionuclides.

  16. Ultra-high pitch chest computed tomography at 70 kVp tube voltage in an anthropomorphic pediatric phantom and non-sedated pediatric patients. Initial experience with 3{sup rd} generation dual-source CT

    Energy Technology Data Exchange (ETDEWEB)

    Hagelstein, Claudia; Henzler, Thomas; Haubenreisser, Holger; Meyer, Mathias; Sudarski, Sonja; Schoenberg, Stefan O.; Neff, K. Wolfgang; Weis, Meike [Univ. Medical Center Mannheim (Germany). Inst. of Clinical Radiology and Nuclear Medicine

    2016-07-01

    Minimizing radiation dose while at the same time preserving image quality is of particular importance in pediatric chest CT. Very recently, CT imaging with a tube voltage of 70 kVp has become clinically available. However, image noise is inversely proportional to the tube voltage. We aimed to investigate radiation dose and image quality of pediatric chest CT performed at 70 kVp in an anthropomorphic pediatric phantom as well as in clinical patients. An anthropomorphic pediatric phantom, which resembles a one-year-old child in physiognomy, was scanned on the 3{sup rd} generation dual-source CT (DSCT) system at 70 kVp and 80 kVp and a fixed ultra low tube-current of 8 mAs to solely evaluate the impact of lowering tube voltage. After the phantom measurements, 18 pediatric patients (mean 29.5 months; range 1-91 months; 21 examinations) underwent 3.2 high-pitch chest CT on the same DSCT system at 70 kVp tube voltage without any sedation. Radiation dose and presence of motion artifacts was compared to a retrospectively identified patient cohort examined at 80 kVp on a 16-slice single-source-CT (SSCT; n = 15; 14/15 with sedation; mean 30.7 months; range 0-96 months; pitch = 1.5) or on a 2{sup nd} generation DSCT without any sedation (n = 6; mean 32.8 months; range 4-61 months; pitch = 3.2). Radiation dose in the phantom scans was reduced by approximately 40% when using a tube voltage of 70 kVp instead of 80 kVp. In the pediatric patient group examined at 70 kVp age-specific effective dose (ED; mean 0.5 ± 0.2 mSv) was significantly lower when compared to the retrospective cohort scanned at 80 kVp on the 16-slice-SSCT (mean ED: 1.0 ± 0.3 mSv; p < 0.0001) and also considerably lower when compared to the cohort scanned at 80 kVp on the 2{sup nd} generation DSCT (mean ED: 0.9 ± 0.5 mSv). None of the prospective, sedation-free CT examinations showed any motion artifacts whereas 13/15 examinations of the retrospective patient cohort scanned at 80 kVp with a pitch of 1

  17. 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)

  18. 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.

  19. 10 kVp rule – An anthropomorphic pelvis phantom imaging study using a CR system: Impact on image quality and effective dose using AEC and manual mode

    International Nuclear Information System (INIS)

    Lança, Luís; Franco, Loris; Ahmed, Abdulfatah; Harderwijk, Marloes; Marti, Chloe; Nasir, Sadeeda; Ndlovu, Junior; Oliveira, Miguel; Santiago, Ana Rita; Hogg, Peter

    2014-01-01

    Purpose: This study aims to investigate the influence of tube potential (kVp) variation in relation to perceptual image quality and effective dose (E) for pelvis using automatic exposure control (AEC) and non-AEC in a Computed Radiography (CR) system. Methods and materials: To determine the effects of using AEC and non-AEC by applying the 10 kVp rule in two experiments using an anthropomorphic pelvis phantom. Images were acquired using 10 kVp increments (60–120 kVp) for both experiments. The first experiment, based on seven AEC combinations, produced 49 images. The mean mAs from each kVp increment were used as a baseline for the second experiment producing 35 images. A total of 84 images were produced and a panel of 5 experienced observers participated for the image scoring using the two alternative forced choice (2AFC) visual grading software. PCXMC software was used to estimate E. Results: A decrease in perceptual image quality as the kVp increases was observed both in non-AEC and AEC experiments, however no significant statistical differences (p > 0.05) were found. Image quality scores from all observers at 10 kVp increments for all mAs values using non-AEC mode demonstrates a better score up to 90 kVp. E results show a statistically significant decrease (p = 0.000) on the 75th quartile from 0.37 mSv at 60 kVp to 0.13 mSv at 120 kVp when applying the 10 kVp rule in non-AEC mode. Conclusion: Using the 10 kVp rule, no significant reduction in perceptual image quality is observed when increasing kVp whilst a marked and significant E reduction is observed

  20. Tomographic anthropomorphic models. Pt. 1

    International Nuclear Information System (INIS)

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

    1989-01-01

    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)

  1. Anthropomorphism in Psychology.

    Science.gov (United States)

    Bakan, David

    This article presents an address on anthropomorphism in psychology. Anthropomorphism assures that human beings are given human characteristics when participating in psychological research. This is significant because the research community does not often report results of studies in the language of feelings, thoughts, or desires, which has led to…

  2. Advanced Radiation DOSimetry phantom (ARDOS): a versatile breathing phantom for 4D radiation therapy and medical imaging

    Science.gov (United States)

    Kostiukhina, Natalia; Georg, Dietmar; Rollet, Sofia; Kuess, Peter; Sipaj, Andrej; Andrzejewski, Piotr; Furtado, Hugo; Rausch, Ivo; Lechner, Wolfgang; Steiner, Elisabeth; Kertész, Hunor; Knäusl, Barbara

    2017-10-01

    A novel breathing phantom was designed for being used in conventional and ion-beam radiotherapy as well as for medical imaging. Accurate dose delivery and patient safety are aimed to be verified for four-dimensional (4D) treatment techniques compensating for breathing-induced tumor motion. The phantom includes anthropomorphic components representing an average human thorax. It consists of real tissue equivalent materials to fulfill the requirements for dosimetric experiments and imaging purposes. The different parts of the torso (lungs, chest wall, and ribs) and the tumor can move independently. Simple regular movements, as well as more advanced patient-specific breathing cycles are feasible while a reproducible setup can be guaranteed. The phantom provides the flexibility to use different types of dosimetric devices and was designed in a way that it is robust, transportable and easy to handle. Tolerance levels and the reliability of the phantom setup were determined in combination with tests on motion accuracy and reproducibility by using infrared optical tracking technology. Different imaging was performed including positron emission tomography imaging, 4D computed tomography as well as real-time in-room imaging. The initial dosimetric benchmarking studies were performed in a photon beam where dose parameters are predictable and the dosimetric procedures well established.

  3. Advanced Radiation DOSimetry phantom (ARDOS): a versatile breathing phantom for 4D radiation therapy and medical imaging.

    Science.gov (United States)

    Kostiukhina, Natalia; Georg, Dietmar; Rollet, Sofia; Kuess, Peter; Sipaj, Andrej; Andrzejewski, Piotr; Furtado, Hugo; Rausch, Ivo; Lechner, Wolfgang; Steiner, Elisabeth; Kertész, Hunor; Knäusl, Barbara

    2017-10-04

    A novel breathing phantom was designed for being used in conventional and ion-beam radiotherapy as well as for medical imaging. Accurate dose delivery and patient safety are aimed to be verified for four-dimensional (4D) treatment techniques compensating for breathing-induced tumor motion. The phantom includes anthropomorphic components representing an average human thorax. It consists of real tissue equivalent materials to fulfill the requirements for dosimetric experiments and imaging purposes. The different parts of the torso (lungs, chest wall, and ribs) and the tumor can move independently. Simple regular movements, as well as more advanced patient-specific breathing cycles are feasible while a reproducible setup can be guaranteed. The phantom provides the flexibility to use different types of dosimetric devices and was designed in a way that it is robust, transportable and easy to handle. Tolerance levels and the reliability of the phantom setup were determined in combination with tests on motion accuracy and reproducibility by using infrared optical tracking technology. Different imaging was performed including positron emission tomography imaging, 4D computed tomography as well as real-time in-room imaging. The initial dosimetric benchmarking studies were performed in a photon beam where dose parameters are predictable and the dosimetric procedures well established.

  4. 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

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

    Science.gov (United States)

    Feng, Shi-Ting; Law, Martin Wai-Ming; Huang, Bingsheng; Ng, Sherry; Li, Zi-Ping; Meng, Quan-Fei; Khong, Pek-Lan

    2010-11-01

    To measure the radiation dose from CT scans in an anthropomorphic phantom using a 64-slice MDCT, and to estimate the associated cancer risk. 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. The effective doses for head, thorax, abdomen and pelvis CT, were 0.7mSv, 3.5mSv, 3.0mSv, 1.3mSv respectively. The organs with the highest dose were; for head CT, salivary gland (22.33mGy); for thorax CT, breast (7.89mGy); for abdomen CT, colon (6.62mGy); for pelvis CT, bladder (4.28mGy). 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%). The effective doses from these common pediatric CT examinations ranged from 0.7mSv to 3.5mSv 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. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  6. Lymphomas of the thorax

    International Nuclear Information System (INIS)

    Frija, J.; Katz, M.; Laval-Jeantet, M.

    1986-01-01

    Chest radiography is of prime importance in all stages of Hodgkin's disease (HD). It can detect HD in asymptomatic individuals; it is essential for initial disease staging; it allows evaluation of response to treatment; and it is indispensible for patient follow-up, since the thorax can be the site of disease recurrence detectable only by radiography. HD commonly affects the mediastinal lymph nodes and the thymus, and more rarely, the trachea, bronchi, heart, and esophagus. The lungs, pleura, and chest wall can also be involved. The frequency of involvement of individual intrathoracic sites varies for initial HD and relapses. Computed tomography (CT) of the thorax will undoubtedly gradually replace all the existing indications for conventional thoracic tomography. During initial work-ups, CT confirmed the presence of adenopathies suspected on standard radiographs and mediastinal tomograms in one of five instances. On five occasions, CT proved useful for adapting the fields for mantle irradiation

  7. An approach to correlate the CTDIvol to organ dose for thorax and abdomen CT taking tube current modulation and patient size into account

    Science.gov (United States)

    Lopez-Rendon, X.; Zanca, F.; Oyen, R.; Bosmans, H.

    2013-03-01

    Purpose: To estimate conversion factors for calculating effective dose (E) and organ dose taking tube current modulation (TCM) and patient size into account in adult thorax and abdomen CT examinations. Method: 99 consecutive adult patients were included in this study. All examinations were performed with TCM (CareDose 4D. Siemens Definition Flash) at 120 kVp and 110 (thorax) and 200 (abdomen) reference mAs. E and organ dose were estimated with PCXMC 2.0 (STUK. Helsinki. Finland). using an extension of the software from a planar geometry to spiral acquisitions of aCT scanner. This software accounts for patient size by rescaling the anthropomorphic phantom to actual patient weights and heights. E and organ doses were normalized to the CTDivol as reported in the patient's report. These conversion factors (dE and dorgan were studied as a function of different patient metrics: lateral and anterior-posterior (AP) diameter. sum of the lateral and AP diameter, area of a cross section image and effective diameter. Results:. No trend was found for any of the metrics neither forE nor for the organs investigated (lungs. breasts. stomach and liver). Average value +/- 2 standard deviation were calculated. For a thorax examination, the average dE was 0.57 +/- 0.14 mSv/mGy. dlungs was 1.26 +/- 0.28 mGy/mGy and dbreasts was 1.29 +/- 0.40 mGy/mGy. For an abdomen scan dE was 0.82 +/- 0.18. mSv/mGy. d,tomooh was 1.42 +/- 0.26 mGy/mGy. dliver was 1.42 +/- 0.30 mGy/mGy. Conclusion:. For the scanner studied, average conversion factors, which account for TCM and patient size, were proposed. This is a first step towards patient-specific dosimetry.

  8. X-ray diagnostics of thorax diseases

    International Nuclear Information System (INIS)

    Kulke, H.M.

    2013-01-01

    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.

  9. Use of an anthropomorphic hand phantom to verify the radiation intensity that is needed to modify the analog and digital radiographic quality; Uso de um fantoma antropomorfo de mao para verificar a intensidade da radiacao que e necessaria para modificar a qualidade da radiografia analogica e a digital

    Energy Technology Data Exchange (ETDEWEB)

    Bandeira, Caroline K.; Vieira, Michele P.M.M., E-mail: kretezel@hotmail.com, E-mail: michele.vieira@ifpr.edu.br [Instituto Federal do Parana (IFPR), Curitiba, PR (Brazil); Felix, Jose E.R., E-mail: felix@anomati.net [Universidade Federal do Triangulo Mineiro (UFTM), Uberaba, MG (Brazil)

    2014-07-01

    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)

  10. 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)

  11. Dosimetry in thorax X-rays

    International Nuclear Information System (INIS)

    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.; Rivera M, T.; Azorin N, J.

    2009-10-01

    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 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)

  12. Elastic models application for thorax image registration

    International Nuclear Information System (INIS)

    Correa Prado, Lorena S; Diaz, E Andres Valdez; Romo, Raul

    2007-01-01

    This work consist of the implementation and evaluation of elastic alignment algorithms of biomedical images, which were taken at thorax level and simulated with the 4D NCAT digital phantom. Radial Basis Functions spatial transformations (RBF), a kind of spline, which allows carrying out not only global rigid deformations but also local elastic ones were applied, using a point-matching method. The applied functions were: Thin Plate Spline (TPS), Multiquadric (MQ) Gaussian and B-Spline, which were evaluated and compared by means of calculating the Target Registration Error and similarity measures between the registered images (the squared sum of intensity differences (SSD) and correlation coefficient (CC)). In order to value the user incurred error in the point-matching and segmentation tasks, two algorithms were also designed that calculate the Fiduciary Localization Error. TPS and MQ were demonstrated to have better performance than the others. It was proved RBF represent an adequate model for approximating the thorax deformable behaviour. Validation algorithms showed the user error was not significant

  13. Application of the Voxeldose software for dosimetric evaluation on the thyroid during thorax-AP irradiation considering the peak voltages (k Vp) most used in diagnostic X-ray

    International Nuclear Information System (INIS)

    Vieira, I.F.; Vieira, J.W.; Leal Neto, V.

    2009-01-01

    The evaluation of the absorbed dose distribution can be obtained through a computational model of exposures (ECM), being one the main difficulties at the specific dosimetric evaluation such as the radiodiagnostic, coupling the Monte Carlo computer code, developed for general use, to a anthropomorphic model. This problem can be solved by the software used in this paper, the VoxelDose, and it consists of an algorithm for X-ray diagnostic sources with the Monte Carlo EGS4 code coupled to the voxel anthropomorphic phantoms MAX (Male Adult voXel) and FAX (Female Adult voXel). The graphic interface allows the user to insert the mos common exams parameters, and to execute the simulation, obtaining conversion coefficients and the estimative of the deposited energy on organs/tissues radio sensible during the routine procedures. The data obtained were organized into graphics showing the thyroid equivalent dose, which is a radio sensible with 20 g mass and a weight factor of 5 %, compared with the effective dose during an irradiation of thorax-AP

  14. 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.

  15. Radation distribution in head & thorax computerized tomography

    Directory of Open Access Journals (Sweden)

    Mohammad Mahdavi

    2014-05-01

    Full Text Available Background: Determination of the exposure levels in the computerized tomography (CT practices is necessary to define the respected national reference levels, quality control of CT centers and the risk assessment for radiation induced cancers. Material and Methods: On the basis of this necessity, the radiation exposure distribution due to common CT practices has been investigated at Razi Hospital CT center in Rasht using tissue-equivalent phantoms and the thermoluminescent dosimeters (TLD. The Head and Thorax phantoms were used with the standard dimensions incorporating holes at the center and edges for TLD placement. Dosimetry was carried out using LiF Mg, Cu, P small chips due to their relatively tissue equivalence, high sensitivity convenient annealing procedure and the non-complex glow curve. Results: Results showed that CTDI for Head is 52.85 mGy and for Body is 68.15mGy. CTDLW for Head is 13.67 mGy and for Body is 16.94mGy . Conclusion: In comparison with other radiographical procedures, patient absorbed doses in CT imaging are usually very high. Content of dose is increased by increase of mAs.

  16. Computational hybrid anthropometric paediatric phantom library for internal radiation dosimetry

    DEFF Research Database (Denmark)

    Xie, Tianwu; Kuster, Niels; Zaidi, Habib

    2017-01-01

    Hybrid computational phantoms combine voxel-based and simplified equation-based modelling approaches to provide unique advantages and more realism for the construction of anthropomorphic models. In this work, a methodology and C++ code are developed to generate hybrid computational phantoms cover...

  17. Computational hybrid anthropometric paediatric phantom library for internal radiation dosimetry

    NARCIS (Netherlands)

    Xie, Tianwu; Kuster, Niels; Zaidi, Habib

    2017-01-01

    Hybrid computational phantoms combine voxel-based and simplified equation-based modelling approaches to provide unique advantages and more realism for the construction of anthropomorphic models. In this work, a methodology and C++ code are developed to generate hybrid computational phantoms covering

  18. Digital radiography of the thorax - the selenium detector compared with other imaging systems

    International Nuclear Information System (INIS)

    Schaefer-Prokop, C.; Prokop, M.

    1996-01-01

    Phantom studies were compared with clinical studies for a comparative analysis of the diagnostic performance of conventional and digital imaging systems. The selenium detector is found to be superior in a number of tasks, and on the whole is judged to adequately perform the multiple tasks of thorax radiography.(Orig.) [de

  19. 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

  20. Thorax deformity, joint hypermobility and anxiety disorder

    International Nuclear Information System (INIS)

    Gulsun, M.; Dumlu, K.; Erbas, M.; Yilmaz, Mehmet B.; Pinar, M.; Tonbul, M.; Celik, C.; Ozdemir, B.

    2007-01-01

    Objective was to evaluate the association between thorax deformities, panic disorder and joint hypermobility. The study includes 52 males diagnosed with thorax deformity, and 40 healthy male controls without thorax deformity, in Tatvan Bitlis and Isparta, Turkey. The study was carried out from 2004 to 2006. The teleradiographic and thoracic lateral images of the subjects were evaluated to obtain the Beighton scores; subjects psychiatric conditions were evaluated using the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-1), and the Hamilton Anxiety Scale (HAM-A) was applied in order to determine the anxiety levels. Both the subjects and controls were compared in sociodemographic, anxiety levels and joint mobility levels. In addition, males with joint hypermobility and thorax deformity were compared to the group with thorax deformity without joint hypermobility. A significant difference in HAM-A scores was found between the groups with thorax deformity and without. In addition, 21 subjects with thorax deformity met the joint hypermobility criteria in the group with thorax deformity and 7 subjects without thorax deformity met the joint hypermobility criteria in the group without thorax deformity, according to Beighton scoring. The Beighton score of subjects with thorax deformity were significantly different from those of the group without deformity. Additionally, anxiety scores of the males with thorax deformity and joint hypermobility were found higher than males with thorax deformity without joint hypermobility. Anxiety disorders, particularly panic disorder, have a significantly higher distribution in males subjects with thorax deformity compared to the healthy control group. In addition, the anxiety level of males with thorax deformity and joint hypermobility is higher than males with thorax deformity without joint hypermobility. (author)

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

    International Nuclear Information System (INIS)

    Costa, Kleber Souza Silva; Barbosa, Antonio Konrado de Santana; Vieira, Jose Wilson; Lima, Fernando Roberto de Andrade

    2011-01-01

    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. 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.

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

    International Nuclear Information System (INIS)

    Wambersie, A.

    1992-01-01

    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

  4. Application of the Voxeldose software for dosimetric evaluation on the thyroid during thorax-AP irradiation considering the peak voltages (k Vp) most used in diagnostic X-ray; Aplicacao do software Voxeldose para avaliacao dosimetrica na tireoide durante irradiacoes de torax-AP nas tensoes de pico (kVp) mais utilizadas em raio-X diagnostico

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, I.F.; Vieira, J.W., E-mail: igoradiologia@hotmail.co, E-mail: jwvieira@br.inter.ne [Instituto Federal de Educacao, Ciencia e Tecnologia de Pernambuco, Recife, PE (Brazil); Leal Neto, V., E-mail: viriatoleal@yahoo.com.b [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear; Lima, F.R.A., E-mail: falima@cnen.gov.b [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear; Centro Regional de Ciencias Nucleares (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2009-07-01

    The evaluation of the absorbed dose distribution can be obtained through a computational model of exposures (ECM), being one the main difficulties at the specific dosimetric evaluation such as the radiodiagnostic, coupling the Monte Carlo computer code, developed for general use, to a anthropomorphic model. This problem can be solved by the software used in this paper, the VoxelDose, and it consists of an algorithm for X-ray diagnostic sources with the Monte Carlo EGS4 code coupled to the voxel anthropomorphic phantoms MAX (Male Adult voXel) and FAX (Female Adult voXel). The graphic interface allows the user to insert the mos common exams parameters, and to execute the simulation, obtaining conversion coefficients and the estimative of the deposited energy on organs/tissues radio sensible during the routine procedures. The data obtained were organized into graphics showing the thyroid equivalent dose, which is a radio sensible with 20 g mass and a weight factor of 5 %, compared with the effective dose during an irradiation of thorax-AP

  5. Digital radiography of the thorax

    International Nuclear Information System (INIS)

    Frija, J.; Kerviler, E. de; Zagdanski, A.M.; Feger, C.; Attal, P.; Laval-jeantet, M.

    1997-01-01

    Digital radiography of the thorax can, now be substituted to conventional chest radiography. Computed radiography with phosphor plates and the new selenium detector are emphasized. The major image processing are explained. Successively the main other methods of digital radiography are described: scanning equalization radiography, laser-digitized radiography and multiwire proportional chambers. Then the advantages and the drawbacks of chest computed radiography are extensively reviewed. (author)

  6. Design of non-anthropomorphic robotic hands for anthropomorphic tasks

    OpenAIRE

    Simó Serra, Edgar; Moreno-Noguer, Francesc; Pérez Gracia, Alba

    2011-01-01

    In this paper, we explore the idea of designing non- anthropomorphic multi-fingered robotic hands for tasks tha t replicate the motion of the human hand. Taking as input data a finite set of rigid-body positions for the five fingertips, we de- velop a method to perform dimensional synthesis for a kinema tic chain with a tree structure, with five branches that share thr ee common joints. We state the forward kinematics equations of relative dis- placements for each serial chain expressed as du...

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

    International Nuclear Information System (INIS)

    Ehler, Eric D; Higgins, Patrick D; Dusenbery, Kathryn E; Barney, Brett M

    2014-01-01

    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)

  8. Anthropomorphism and Intentionality Improve Memory for Events

    Science.gov (United States)

    Baker, Lewis J.; Hymel, Alicia M.; Levin, Daniel T.

    2018-01-01

    Several studies have explored the determinants of anthropomorphism: the tendency to endow nonhuman agents with human features, goals, and intentions. Less is known of the cognitive benefits that may arise from anthropomorphism. Following research in narrative comprehension, we explored how the attribution of human-like features and intentional…

  9. 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.

  10. Pre-operative evaluation for thorax surgery

    International Nuclear Information System (INIS)

    Silva Luis, Saenz; Morales, Oscar Alberto

    2002-01-01

    A pre-operative analysis of the function of the breathing system is made in the patient that will be taken to thorax surgery. The paper includes risk factors, pre-operative clinical evaluation and of breathing and cardiovascular system

  11. Reminders of Social Connection Can Attenuate Anthropomorphism.

    Science.gov (United States)

    Bartz, Jennifer A; Tchalova, Kristina; Fenerci, Can

    2016-12-01

    It is a fundamental human need to secure and sustain a sense of social belonging. Previous research has shown that individuals who are lonely are more likely than people who are not lonely to attribute humanlike traits (e.g., free will) to nonhuman agents (e.g., an alarm clock that makes people get up by moving away from the sleeper), presumably in an attempt to fulfill unmet needs for belongingness. We directly replicated the association between loneliness and anthropomorphism in a larger sample ( N = 178); furthermore, we showed that reminding people of a close, supportive relationship reduces their tendency to anthropomorphize. This finding provides support for the idea that the need for belonging has causal effects on anthropomorphism. Last, we showed that attachment anxiety-characterized by intense desire for and preoccupation with closeness, fear of abandonment, and hypervigilance to social cues-was a stronger predictor of anthropomorphism than loneliness was. This finding helps clarify the mechanisms underlying anthropomorphism and supports the idea that anthropomorphism is a motivated process reflecting the active search for potential sources of connection.

  12. 49 CFR 572.196 - Thorax without arm.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Thorax without arm. 572.196 Section 572.196... Dummy, Small Adult Female § 572.196 Thorax without arm. (a) The thorax is part of the upper torso... (drawing 180-0000) with the arm (180-6000) on the impacted side removed. The dummy's thorax is equipped...

  13. 49 CFR 572.195 - Thorax with arm.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Thorax with arm. 572.195 Section 572.195... Dummy, Small Adult Female § 572.195 Thorax with arm. (a) The thorax is part of the upper torso assembly shown in drawing 180-3000. For the thorax with arm impact test, the dummy is tested as a complete...

  14. New concepts in thorax-radiography

    International Nuclear Information System (INIS)

    Biebesheimer, V.; Buchmann, F.

    1987-01-01

    New requirements in thorax-radiography like economy and low patient-dose, are of increasing importance. Using new concepts, these requirements together with high image-quality were fulfilled in a new thorax-system, the pulmo DIAGNOST 100. This was possible by the utilization of the slit-radiography principle together with a linear image intensifier. It resulted in superior quality for the fully automated system. (orig.) [de

  15. Phantom Pain

    Science.gov (United States)

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

  16. Human phantom

    CERN Multimedia

    CERN PhotoLab

    1973-01-01

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

  17. Primary classical hemangiopericytomas of thorax.

    Science.gov (United States)

    Bicakcioglu, Pinar; Aydin, Ertan; Celik, Ali; Demirag, Funda; Karaoglanoglu, Nurettin

    2012-07-01

    Hemangiopericytoma, an uncommon hypervascular tumor, occurs anywhere in the body with capillary vessels originating from the pericyte. These tumors most frequently occur in the musculature of the lower extremities and retroperitoneum, but are rarely seen in the thoracic cavity. The objective of this study is to present primary classical hemangiopericytomas of the thorax together with a literature review. The postoperative pathologic records of 17,165 operations that were performed between January 1990 and December 2010 in the clinic were retrospectively searched, and the files of 6 cases with the diagnosis of primary classical hemangiopericytoma were analyzed for clinical characteristics of patients, surgical procedures, histopathologic features, treatments after surgery, and morbidity and mortality results. There were 4 female and 2 male patients with an average age of 30.3 years (range, 15 to 60 years). Three patients had thoracic wall lesions, 2 patients had intrathoracic extrapulmonary lesions, and 1 patient had mediastinal lesion. Four left and two right posterolateral thoracotomies were performed. Chest wall resection was performed in 3 patients, intrathoracic extrapulmonary mass excision in 2 patients, and mediastinal mass excision and left lower lobectomy in 1 patient. Postoperative histopathologic diagnoses were primary classical hemangiopericytomas in 4 patients and primary classical malignant hemangiopericytomas in 2 patients. Four patients underwent reoperation for recurrence. In the follow-up period, 2 patients are still alive at 30 months and 14 years postoperatively; 3 patients died at 7, 8, and 16 years postoperatively. One patient was lost to follow-up. All 3 mortalities were related to the recurrence or distant metastasis of the tumor. Although hemangiopericytomas are benign or malignant tumors, they generally display malignant behaviors. The risk of recurrence and distant metastasis occurs even many years after resection, suggesting that the

  18. Construction of mammography phantoms with a 3D printer and tested with a TIMEPIX system

    Science.gov (United States)

    Calderón-García, J. S.; Roque, G. A.; Ávila, C. A.

    2017-11-01

    We present a new mammography phantom made of hydroxyapatite crystals with different sizes and shapes, to emulate anthropomorphic microcalcifications, which we locate at different depths of a PMMA embedding material. The aim of the phantom presented is to address some issues of the standard commercial ones that are being used for comparing 3D vs 2D mammography systems. We present X-ray images, taken under the same conditions, for both a commercial phantom and the new proposed phantom. We compare signal to noise ratios (SNR) obtained for both cases. This phantom has been constructed to be easily assembled within different configurations to emulate modified features that might be of medical interest.

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

    International Nuclear Information System (INIS)

    Dantas, Bernardo Maranhao

    1998-01-01

    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)

  20. An anatomically realistic temperature phantom for radiofrequency heating measurements

    Science.gov (United States)

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

    2014-01-01

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

  1. 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

    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

  2. Influence of dose reduction and iterative reconstruction on CT calcium scores : a multi-manufacturer dynamic phantom study

    NARCIS (Netherlands)

    van der Werf, N R; Willemink, M J; Willems, T P; Greuter, M J W; Leiner, T

    To evaluate the influence of dose reduction in combination with iterative reconstruction (IR) on coronary calcium scores (CCS) in a dynamic phantom on state-of-the-art CT systems from different manufacturers. Calcified inserts in an anthropomorphic chest phantom were translated at 20 mm/s

  3. A phantom-based JAFROC observer study of two CT reconstruction methods: the search for optimisation of lesion detection and effective dose

    Science.gov (United States)

    Thompson, John D.; Chakraborty, Dev P.; Szczepura, Katy; Vamvakas, Ioannis; Tootell, Andrew; Manning, David J.; Hogg, Peter

    2015-03-01

    Purpose: To investigate the dose saving potential of iterative reconstruction (IR) in a computed tomography (CT) examination of the thorax. Materials and Methods: An anthropomorphic chest phantom containing various configurations of simulated lesions (5, 8, 10 and 12mm; +100, -630 and -800 Hounsfield Units, HU) was imaged on a modern CT system over a tube current range (20, 40, 60 and 80mA). Images were reconstructed with (IR) and filtered back projection (FBP). An ATOM 701D (CIRS, Norfolk, VA) dosimetry phantom was used to measure organ dose. Effective dose was calculated. Eleven observers (15.11+/-8.75 years of experience) completed a free response study, localizing lesions in 544 single CT image slices. A modified jackknife alternative free-response receiver operating characteristic (JAFROC) analysis was completed to look for a significant effect of two factors: reconstruction method and tube current. Alpha was set at 0.05 to control the Type I error in this study. Results: For modified JAFROC analysis of reconstruction method there was no statistically significant difference in lesion detection performance between FBP and IR when figures-of-merit were averaged over tube current (F(1,10)=0.08, p = 0.789). For tube current analysis, significant differences were revealed between multiple pairs of tube current settings (F(3,10) = 16.96, pConclusion: The free-response study suggests that lesion detection can be optimized at 40mA in this phantom model, a measured effective dose of 0.97mSv. In high-contrast regions the diagnostic value of IR, compared to FBP, is less clear.

  4. SimDoseCT: dose reporting software based on Monte Carlo simulation for a 320 detector-row cone-beam CT scanner and ICRP computational adult phantoms

    Science.gov (United States)

    Cros, Maria; Joemai, Raoul M. S.; Geleijns, Jacob; Molina, Diego; Salvadó, Marçal

    2017-08-01

    This study aims to develop and test software for assessing and reporting doses for standard patients undergoing computed tomography (CT) examinations in a 320 detector-row cone-beam scanner. The software, called SimDoseCT, is based on the Monte Carlo (MC) simulation code, which was developed to calculate organ doses and effective doses in ICRP anthropomorphic adult reference computational phantoms for acquisitions with the Aquilion ONE CT scanner (Toshiba). MC simulation was validated by comparing CTDI measurements within standard CT dose phantoms with results from simulation under the same conditions. SimDoseCT consists of a graphical user interface connected to a MySQL database, which contains the look-up-tables that were generated with MC simulations for volumetric acquisitions at different scan positions along the phantom using any tube voltage, bow tie filter, focal spot and nine different beam widths. Two different methods were developed to estimate organ doses and effective doses from acquisitions using other available beam widths in the scanner. A correction factor was used to estimate doses in helical acquisitions. Hence, the user can select any available protocol in the Aquilion ONE scanner for a standard adult male or female and obtain the dose results through the software interface. Agreement within 9% between CTDI measurements and simulations allowed the validation of the MC program. Additionally, the algorithm for dose reporting in SimDoseCT was validated by comparing dose results from this tool with those obtained from MC simulations for three volumetric acquisitions (head, thorax and abdomen). The comparison was repeated using eight different collimations and also for another collimation in a helical abdomen examination. The results showed differences of 0.1 mSv or less for absolute dose in most organs and also in the effective dose calculation. The software provides a suitable tool for dose assessment in standard adult patients undergoing CT

  5. SimDoseCT: dose reporting software based on Monte Carlo simulation for a 320 detector-row cone-beam CT scanner and ICRP computational adult phantoms.

    Science.gov (United States)

    Cros, Maria; Joemai, Raoul M S; Geleijns, Jacob; Molina, Diego; Salvadó, Marçal

    2017-07-17

    This study aims to develop and test software for assessing and reporting doses for standard patients undergoing computed tomography (CT) examinations in a 320 detector-row cone-beam scanner. The software, called SimDoseCT, is based on the Monte Carlo (MC) simulation code, which was developed to calculate organ doses and effective doses in ICRP anthropomorphic adult reference computational phantoms for acquisitions with the Aquilion ONE CT scanner (Toshiba). MC simulation was validated by comparing CTDI measurements within standard CT dose phantoms with results from simulation under the same conditions. SimDoseCT consists of a graphical user interface connected to a MySQL database, which contains the look-up-tables that were generated with MC simulations for volumetric acquisitions at different scan positions along the phantom using any tube voltage, bow tie filter, focal spot and nine different beam widths. Two different methods were developed to estimate organ doses and effective doses from acquisitions using other available beam widths in the scanner. A correction factor was used to estimate doses in helical acquisitions. Hence, the user can select any available protocol in the Aquilion ONE scanner for a standard adult male or female and obtain the dose results through the software interface. Agreement within 9% between CTDI measurements and simulations allowed the validation of the MC program. Additionally, the algorithm for dose reporting in SimDoseCT was validated by comparing dose results from this tool with those obtained from MC simulations for three volumetric acquisitions (head, thorax and abdomen). The comparison was repeated using eight different collimations and also for another collimation in a helical abdomen examination. The results showed differences of 0.1 mSv or less for absolute dose in most organs and also in the effective dose calculation. The software provides a suitable tool for dose assessment in standard adult patients undergoing CT

  6. Phantom Pain

    Science.gov (United States)

    ... Because this is yet another version of tangled sensory wires, the result can be pain. A number of other factors are believed to contribute to phantom pain, including damaged nerve endings, scar tissue at the site of the amputation and the physical memory of pre-amputation pain in the affected area. ...

  7. Cardiovascular dosimetry using hybrid computational phantoms after external radiotherapy

    International Nuclear Information System (INIS)

    Moignier, Alexandra

    2014-01-01

    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)

  8. Heart dosimetry in radiotherapy with hybrid computational phantoms

    International Nuclear Information System (INIS)

    Moignier, Cyril

    2014-01-01

    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)

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

    International Nuclear Information System (INIS)

    Farah, J.; Broggio, D.; Franck, D.

    2010-01-01

    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

  10. Bioinspired Fingertip for Anthropomorphic Robotic Hands

    Directory of Open Access Journals (Sweden)

    Marco Controzzi

    2014-01-01

    Full Text Available Background: An artificial fingertip with mechanical features and appearance similar to the human fingertip could represent a significant step forward towards the development of the next generation artificial hands. However, so far, a fingertip showing a good trade-off among mechanical features, appearance and anthropomorphism, along with its 3D computational model, is still missing.

  11. 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; Torshabi, Ahmad Esmaili; Miandoab, Payam Samadi; Baghizadeh, Amin

    2016-01-08

    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

  12. Computerized Axial Tomography in thorax trauma

    International Nuclear Information System (INIS)

    Zuluaga, Alejandro

    1997-01-01

    The great presentation frequency and the high morbid mortality, make of the thorax trauma a topic of great importance and of constant investigation, where the images have been useful in the evaluation of lesions, to define pathologies, like guide for the drainage of pleural collections and other evaluations; the paper includes a protocol, mediastine, and lesions among other topics

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    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...... 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...

  14. 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

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    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

  16. 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

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

    Science.gov (United States)

    Bondarenko, V A; Mitrikas, V G

    2007-01-01

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

  18. Central venous obstruction in the thorax

    International Nuclear Information System (INIS)

    Collin, G.; Jones, R.G.; Willis, A.P.

    2015-01-01

    Central venous stenosis and occlusion can occur secondary to a spectrum of conditions ranging from aggressive malignancy to benign extrinsic anatomical compression in otherwise healthy individuals. Irrespective of aetiology, significant morbidity in the acute setting and long term can occur unless prompt accurate diagnosis and appropriate management is initiated, the radiologist being central to both. The present review will provide radiologists with a thorough illustration and explanation of the range of central venous conditions in the thorax (including deep vein thrombosis, thoracic outlet syndrome, haemodialysis, and malignancy related causes), the salient imaging findings and interventional management using case examples from the authors' practice. - Highlights: • We show a range of causes of central venous disease in the thorax. • We provide information about different imaging and management strategies. • We show several cases with successes and complications of endovascular management

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

    International Nuclear Information System (INIS)

    Seifert, H.; Jesberger, H.J.; Schneider, G.; Rein, L.; Blass, G.; Limbach, H.G.; Niewald, M.; Sitzmann, F.C.; Kramann, B.

    1998-01-01

    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.)

  20. 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

  1. 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.

  2. Bioassay Phantoms Using Medical Images and Computer Aided Manufacturing

    International Nuclear Information System (INIS)

    Xu, X. Geroge

    2011-01-01

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

  3. SU-G-206-05: A Comparison of Head Phantoms Used for Dose Determination in Imaging Procedures

    International Nuclear Information System (INIS)

    Xiong, Z; Vijayan, S; Kilian-Meneghin, J; Rudin, S; Bednarek, D

    2016-01-01

    Purpose: To determine similarities and differences between various head phantoms that might be used for dose measurements in diagnostic imaging procedures. Methods: We chose four frequently used anthropomorphic head phantoms (SK-150, PBU-50, RS-240T and Alderson Rando), a computational patient phantom (Zubal) and the CTDI head phantom for comparison in our study. We did a CT scan of the head phantoms using the same protocol and compared their dimensions and CT numbers. The scan data was used to calculate dose values for each of the phantoms using EGSnrc Monte Carlo software. An .egsphant file was constructed to describe these phantoms using a Visual C++ program for DOSXYZnrc/EGSnrc simulation. The lens dose was calculated for a simulated CBCT scan using DOSXYZnrc/EGSnrc and the calculated doses were validated with measurements using Gafchromic film and an ionization chamber. Similar calculations and measurements were made for PA radiography to investigate the attenuation and backscatter differences between these phantoms. We used the Zubal phantom as the standard for comparison since it was developed based on a CT scan of a patient. Results: The lens dose for the Alderson Rando phantom is around 9% different than the Zubal phantom, while the lens dose for the PBU-50 phantom was about 50% higher, possibly because its skull thickness and the density of bone and soft tissue are lower than anthropometric values. The lens dose for the CTDI phantom is about 500% higher because of its totally different structure. The entrance dose profiles are similar for the five anthropomorphic phantoms, while that for the CTDI phantom was distinctly different. Conclusion: The CTDI and PBU-50 head phantoms have substantially larger lens dose estimates in CBCT. The other four head phantoms have similar entrance dose with backscatter hence should be preferred for dose measurement in imaging procedures of the head. Partial support from NIH Grant R01-EB002873 and Toshiba Medical Systems

  4. The "Cutopia" paradox: anthropomorphism as entertainment

    OpenAIRE

    McRae, Donna Leanna; Vale, Michael Charles

    2016-01-01

    An infant chimpanzee, dressed in riotous checks, bowtie and braces, cradled in human arms while it regards a camera, is perhaps further from us than a tiger lurking in the deepest jungle. Anthropomorphic sentiment negates empathy, blinding us to the real animal behind the “character.” The engaging creature we imagine we’d like to hold and protect is the product, most likely, of violent separation and trauma, stolen in order to bring us this enjoyment. We read the comical face, celebrating wha...

  5. Status and Trends of the Anthropomorphic Robotics

    Directory of Open Access Journals (Sweden)

    S. P. Hurs

    2016-01-01

    Full Text Available The paper considers a number of current developments in the field of anthropomorphic robotics, namely robotic exoskeletons, android platform with copying control systems, android platform with autonomous control systems, avatars, and androids. Highlights the key subsystems of the robotic platform such as sensitization tools, tools of self-diagnostics, security and prioritization, a power subsystem, and computer system. Identifies the most important subsystem of a “future soldier” to represent an equipage as a multifunctional active exoskeleton, completed with the necessary equipment.The paper shows the main problems the developers of anthropomorphic robotics face. For example, many degrees of the human body freedom curb a creation of the actuating mechanisms of robots, which fit the human anatomy as much as possible. For the human sizes the specific characteristics of traditional types of actuators, such as electromechanical, electro-hydraulic and electro-pneumatic are worse than those of the human muscles. Clearly, the greatest prospects in this area are associated with artificial muscles. There is also no so far a solution for the problem of creating the feedbacks in all kinds of senses to ensure that an operator has a feeling that he is in the place of the robot. There is much tension around the issue of creating a perfect remote control system that allows the operator to obtain unambiguous signals to control the robot. There is currently no completely autonomous control system with elements of artificial intelligence. Particular attention is paid to the problems of creating power sources that can provide affordable autonomy for mobile robotic systems. The most, presently, promising power sources are mentioned.The paper considers some development aspects of the control system, which is capable to run in a copier, supervisory, combined and offline modes. Presents the most important functions of the robot sensory system. Shows some aspects

  6. Anthropomorphic master/slave manipulator system

    Science.gov (United States)

    Vykukal, H. C.; King, R. F.; Vallotton, W. C. (Inventor)

    1977-01-01

    An anthropomorphic master/slave manipulator system including master arm apparatus with a plurality of master tubular articulated portions is outlined. Objectives of this investion were to provide a system that accurately and smoothly simulates human limb movement at a remote location. The system has a high frequency response, a high structural stiffness and a design that protects the components of the slave mechanism. Simulation of human movements is possible in outer space, underwater, and in a hazardous environment such as in a high radiation area. The equivalent ability, dexterity, and strength of a human arm are simulated.

  7. Systematic Interpretation of Adult Thorax Radiography

    Directory of Open Access Journals (Sweden)

    Torel Ogur

    2009-10-01

    Full Text Available Thorax x-ray film is a routine radiological test which is commonly ordered, relatively inexpensive and available for most of the health services. It also offers numerous useful information in medical decision making in a lot of clinical situations. So it is very important to learn to interpret effectively chest x ray film in clinical practice, for medical students and physicians. This review is intended to give a basic opinion for systematic review of chest x-ray film. [TAF Prev Med Bull 2009; 8(5.000: 427-436

  8. Systematic Interpretation of Adult Thorax Radiography

    OpenAIRE

    Torel Ogur; Ergun Ucar

    2009-01-01

    Thorax x-ray film is a routine radiological test which is commonly ordered, relatively inexpensive and available for most of the health services. It also offers numerous useful information in medical decision making in a lot of clinical situations. So it is very important to learn to interpret effectively chest x ray film in clinical practice, for medical students and physicians. This review is intended to give a basic opinion for systematic review of chest x-ray film. [TAF Prev Med Bull 2009...

  9. Mechanics of the thorax in flies.

    Science.gov (United States)

    Deora, Tanvi; Gundiah, Namrata; Sane, Sanjay P

    2017-04-15

    Insects represent more than 60% of all multicellular life forms, and are easily among the most diverse and abundant organisms on earth. They evolved functional wings and the ability to fly, which enabled them to occupy diverse niches. Insects of the hyper-diverse orders show extreme miniaturization of their body size. The reduced body size, however, imposes steep constraints on flight ability, as their wings must flap faster to generate sufficient forces to stay aloft. Here, we discuss the various physiological and biomechanical adaptations of the thorax in flies which enabled them to overcome the myriad constraints of small body size, while ensuring very precise control of their wing motion. One such adaptation is the evolution of specialized myogenic or asynchronous muscles that power the high-frequency wing motion, in combination with neurogenic or synchronous steering muscles that control higher-order wing kinematic patterns. Additionally, passive cuticular linkages within the thorax coordinate fast and yet precise bilateral wing movement, in combination with an actively controlled clutch and gear system that enables flexible flight patterns. Thus, the study of thoracic biomechanics, along with the underlying sensory-motor processing, is central in understanding how the insect body form is adapted for flight. © 2017. Published by The Company of Biologists Ltd.

  10. Anthropomorphic Networks as Representatives of Global Consciousness

    Directory of Open Access Journals (Sweden)

    Sergii Yahodzinskyi

    2018-02-01

    Full Text Available There has been analyzed a phenomenon of global consciousness, and its cultural and historical, civilizational dimensions have been substantiated. There has been demonstrated that the concept of planetary consciousness, global thinking, noosphere was described for the first time in the philosophy of cosmism. However, in modern conditions ideas of representatives of the naturalistic philosophical direction of cosmism have not lost their heuristic potential. They can be reconsidered in a new fashion within the context of emerging anthropomorphic (human dimension networks. There has been proved that global consciousness is a component of the social and cultural potential of global information networks defining vectors to prospects of humanity progress in the 21st century. Relying on methodology of the structural and functional analysis, the author arrives at a conclusion about global networks obtaining the status of representatives of global consciousness. This is the area of networks where all relevant information is concentrated – from statistical data to scientific and technical information. Access to these data is limited by human abilities and is realized in the form of discrete requests with using heuristic algorithms of information procession. A suggestion is introduced considering the fact that modern society being a self-organized system seeks to gain stable condition. Anthropomorphic networks are means of decreasing social entropy, which is growing as a result of any kind of human intervention into social processes. Thus, for the first time a human is challenged by their intellect, ability to create, discover and control.

  11. 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

  12. 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.

  13. SIMULASI RONTGEN THORAX BERBASIS ANDROID SEBAGAI MEDIA EDUKASI

    Directory of Open Access Journals (Sweden)

    Dhanar Intan Surya Saputra

    2013-08-01

    Full Text Available Android merupakan sistem operasi mobile yang open platform, dimana memungkinkan pihak ketiga untuk melakukan pengembangan dalam aplikasinya.Hal ini mengakibatkan banyak para developer atau pengembang yang untuk membuat aplikasi guna memenuhi kebutuhan masyarakat pengguna Android. Pemeriksaan Thorax merupakan salah satu pemeriksaan yang paling sering dilakukan terhadap setiap orang jika mengalami masalah pada kesehatannya, hal ini sangat berfungsi untuk menilai kesehatan paru-paru, pemeriksaan thorax juga sebagai salah satu item dalam melakukan check-up seseorang. Indikasi pemeriksaan thorax diantaranya : Bronchopneumonia, TB paru, Bronkhitis, Atelektasis, Trauma, dan Tumor serta beberapa indikasi yang lainya. Melihat peluang untuk mengembangkan aplikasi berbasis Android serta adanya kebutuhan masyarakat akan informasi yang berkaitan dengan pemeriksaan Thorax, maka sangat memungkinkan untuk membuat dan mengembangkan sebuah aplikasi simulasi foto Rontgen Thorax berbasis Android sebagai media edukasi bagi masyarakat khususnya para pengguna smartphone Android.

  14. 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 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...

  15. Preliminary Study on Hybrid Computational Phantom for Radiation Dosimetry Based on Subdivision Surface

    International Nuclear Information System (INIS)

    Jeong, Jong Hwi; Choi, Sang Hyoun; Cho, Sung Koo; Kim, Chan Hyeong

    2007-01-01

    The anthropomorphic computational phantoms are classified into two groups. One group is the stylized phantoms, or MIRD phantoms, which are based on mathematical representations of the anatomical structures. The shapes and positions of the organs and tissues in these phantoms can be adjusted by changing the coefficients of the equations in use. The other group is the voxel phantoms, which are based on tomographic images of a real person such as CT, MR and serially sectioned color slice images from a cadaver. Obviously, the voxel phantoms represent the anatomical structures of a human body much more realistically than the stylized phantoms. A realistic representation of anatomical structure is very important for an accurate calculation of radiation dose in the human body. Consequently, the ICRP recently has decided to use the voxel phantoms for the forthcoming update of the dose conversion coefficients. However, the voxel phantoms also have some limitations: (1) The topology and dimensions of the organs and tissues in a voxel model are extremely difficult to change, and (2) The thin organs, such as oral mucosa and skin, cannot be realistically modeled unless the voxel resolution is prohibitively high. Recently, a new approach has been implemented by several investigators. The investigators converted their voxel phantoms to hybrid computational phantoms based on NURBS (Non-Uniform Rational B-Splines) surface, which is smooth and deformable. It is claimed that these new phantoms have the flexibility of the stylized phantom along with the realistic representations of the anatomical structures. The topology and dimensions of the anatomical structures can be easily changed as necessary. Thin organs can be modeled without affecting computational speed or memory requirement. The hybrid phantoms can be also used for 4-D Monte Carlo simulations. In this preliminary study, the external shape of a voxel phantom (i.e., skin), HDRK-Man, was converted to a hybrid computational

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    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

  17. Reconstruction of voxel phantoms for skin dosimetry

    International Nuclear Information System (INIS)

    Antunes, Paula Cristina Guimaraes

    2010-01-01

    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

  18. Computer tomographic phantom

    International Nuclear Information System (INIS)

    Lonn, A.H.R.; Jacobsen, D.R.; Zech, D.J.

    1988-01-01

    A reference phantom for computer tomography employs a flexible member with means for urging the flexible member into contact along the curved surface of the lumbar region of a human patient. In one embodiment, the reference phantom is pre-curved in an arc greater than required. Pressure from the weight of a patient laying upon the reference phantom is effective for straightening out the curvature sufficiently to achieve substantial contact along the lumbar region. The curvature of the reference phantom may be additionally distorted by a resilient pad between the resilient phantom and a table for urging it into contact with the lumbar region. In a second embodiment of the invention, a flexible reference phantom is disposed in a slot in the top of a resilient cushion. The resilient cushion and reference phantom may be enclosed in a flexible container. A partially curved reference phantom in a slot in a resilient cushion is also contemplated. (author)

  19. Research article – Optimisation of paediatrics computed radiographyfor full spine curvature measurements using a phantom: a pilot study

    NARCIS (Netherlands)

    Daniel de Linde; Loris Franco; Catarina Serrenho; Peter Hogg; Ifrah Akhtar; José Antonio Garcia; Seraphine de Haan; Martine Thorskog; Cláudia Reis; Junior Ndlovu

    2015-01-01

    Aim: Optimise a set of exposure factors, with the lowest effective dose, to delineate spinal curvature with the modified Cobb method in a full spine using computed radiography (CR) for a 5-year-old paediatric anthropomorphic phantom. Methods: Images were acquired by varying a set of parameters:

  20. Doses Received by Patients during Thorax X-Ray Examinations

    Directory of Open Access Journals (Sweden)

    Nsikan U. Esen

    2013-03-01

    Full Text Available Introduction Radiation exposures from diagnostic medical examinations are generally low and are almost always justified by the benefits of accurate diagnosis of possible disease conditions. Therefore, entrance skin dose (ESD, body organ dose (BOD, and effective dose (ED from adult patients undergoing routine thorax posterior-anterior (PA and thorax right lateral (RLAT were estimated in University Hospital, Port Harcourt, Southern Nigeria. Materials and Methods Totally, 102 patients were considered in this work. Using software packages to carry out ESD, BOD, and ED is a recent resource in dosimetry and is being widely used in hospitals. The software used in this work was  CALDose_X 5.0. The software makes use of the technical exposure parameters and the tube output of the X-ray machine. Results The estimated ESD median values were 0.96 and 1.85 mGy for thorax posterior anterior (PA and right lateral (RLAT, respectively. The highest BOD was in the adrenals (270 µGy for thorax PA and Liver (263 µGy for thorax RLAT. Similarly, ED for thorax PA and RLAT examination were 0.068 and 0.107 mGy, respectively. Conclusion It could be observed that examinations that imparted the highest ESD were thorax PA when compared with the established dose level. Therefore, these results call for quality assurance program (QAP in diagnostic X-ray units in Nigeria hospitals.

  1. 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)

  2. Dosimetry in computerized tomography and evaluation of doses in organs in thorax scanning

    International Nuclear Information System (INIS)

    Alonso, Thêssa Cristina

    2016-01-01

    Computed tomography has promoted improvement of the diagnostic process by producing anatomical cut images with high quality and contrast between soft tissues which have very similar absorption of the X-ray beams. The objective of this study is to evaluate the technological park of CT in Brazil correlated with the wide world, and carry out studies of experimental dosimetry to understand the dose distribution feature using phantoms and different methods of measurement of kerma index, as well as perform measures of local doses in sensitive organs. To study the scanner geographic distribution and supply of computed tomography tests in Brazil, a comparison has been made with results found with the specified reference by Brazilian law (Ordinance GM / MS No. 1101, 2002; Resolution RE nº1016, 2006). For dosimetry studies, It was used a standard chest phantom and the anthropomorphic phantom. For image quality evaluation, it was used the CATPHAN-600 phantom. Scans were performed in a GE scanner, Discovery model with 64 channels. Dose measurements have been performed by using a pencil ionization chamber, thermoluminescent dosimeters and radiochromic film strips. Sensitive organ shielding devices were evaluated in order to verify their efficiency in organ dose reduction and its influence in the quality of image. Considering Brazilian population, the scanner park showed a greater amount than the minimum parameter recommended by Brazilian law. Dose measurements using three different methods showed the correct procedure of metrological reliability of the measurement system. The findings and conclusions of this study may contribute to the improvement of local practices in Computed Tomography tests, inserted in context of radiological protection in order to define reference levels for optimized diagnosis, and image quality control. (author)

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

    International Nuclear Information System (INIS)

    Pavan, Ana Luiza Menegatti; Alvarez, Matheus; Alves, Allan Felipe Fattori; Rosa, Maria Eugenia Dela; Miranda, Jose Ricardo de Arruda

    2014-01-01

    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)

  4. Anthropomorphic Robot Design and User Interaction Associated with Motion

    Science.gov (United States)

    Ellis, Stephen R.

    2016-01-01

    Though in its original concept a robot was conceived to have some human-like shape, most robots now in use have specific industrial purposes and do not closely resemble humans. Nevertheless, robots that resemble human form in some way have continued to be introduced. They are called anthropomorphic robots. The fact that the user interface to all robots is now highly mediated means that the form of the user interface is not necessarily connected to the robots form, human or otherwise. Consequently, the unique way the design of anthropomorphic robots affects their user interaction is through their general appearance and the way they move. These robots human-like appearance acts as a kind of generalized predictor that gives its operators, and those with whom they may directly work, the expectation that they will behave to some extent like a human. This expectation is especially prominent for interactions with social robots, which are built to enhance it. Often interaction with them may be mainly cognitive because they are not necessarily kinematically intricate enough for complex physical interaction. Their body movement, for example, may be limited to simple wheeled locomotion. An anthropomorphic robot with human form, however, can be kinematically complex and designed, for example, to reproduce the details of human limb, torso, and head movement. Because of the mediated nature of robot control, there remains in general no necessary connection between the specific form of user interface and the anthropomorphic form of the robot. But their anthropomorphic kinematics and dynamics imply that the impact of their design shows up in the way the robot moves. The central finding of this report is that the control of this motion is a basic design element through which the anthropomorphic form can affect user interaction. In particular, designers of anthropomorphic robots can take advantage of the inherent human-like movement to 1) improve the users direct manual control over

  5. Asbestos-related diseases of the thorax

    International Nuclear Information System (INIS)

    Hieckel, H.G.; Hering, K.G.

    2010-01-01

    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.) [de

  6. Embodied neurofeedback with an anthropomorphic robotic hand.

    Science.gov (United States)

    Braun, Niclas; Emkes, Reiner; Thorne, Jeremy D; Debener, Stefan

    2016-11-21

    Neurofeedback-guided motor imagery training (NF-MIT) has been suggested as a promising therapy for stroke-induced motor impairment. Whereas much NF-MIT research has aimed at signal processing optimization, the type of sensory feedback given to the participant has received less attention. Often the feedback signal is highly abstract and not inherently coupled to the mental act performed. In this study, we asked whether an embodied feedback signal is more efficient for neurofeedback operation than a non-embodiable feedback signal. Inspired by the rubber hand illusion, demonstrating that an artificial hand can be incorporated into one's own body scheme, we used an anthropomorphic robotic hand to visually guide the participants' motor imagery act and to deliver neurofeedback. Using two experimental manipulations, we investigated how a participant's neurofeedback performance and subjective experience were influenced by the embodiability of the robotic hand, and by the neurofeedback signal's validity. As pertains to embodiment, we found a promoting effect of robotic-hand embodiment in subjective, behavioral, electrophysiological and electrodermal measures. Regarding neurofeedback signal validity, we found some differences between real and sham neurofeedback in terms of subjective and electrodermal measures, but not in terms of behavioral and electrophysiological measures. This study motivates the further development of embodied feedback signals for NF-MIT.

  7. Seeing More Than Human: Autism and Anthropomorphic Theory of Mind

    Directory of Open Access Journals (Sweden)

    Gray Atherton

    2018-04-01

    Full Text Available Theory of mind (ToM is defined as the process of taking another’s perspective. Anthropomorphism can be seen as the extension of ToM to non-human entities. This review examines the literature concerning ToM and anthropomorphism in relation to individuals with Autism Spectrum Disorder (ASD, specifically addressing the questions of how and why those on the spectrum both show an increased interest for anthropomorphism and may even show improved ToM abilities when judging the mental states of anthropomorphic characters. This review highlights that while individuals with ASD traditionally show deficits on a wide range of ToM tests, such as recognizing facial emotions, such ToM deficits may be ameliorated if the stimuli presented is cartoon or animal-like rather than in human form. Individuals with ASD show a greater interest in anthropomorphic characters and process the features of these characters using methods typically reserved for human stimuli. Personal accounts of individuals with ASD also suggest they may identify more closely with animals than other humans. It is shown how the social motivations hypothesized to underlie the anthropomorphizing of non-human targets may lead those on the spectrum to seek social connections and therefore gain ToM experience and expertise amongst unlikely sources.

  8. A case of posttraumatic splenic translocation into the thorax

    International Nuclear Information System (INIS)

    Sosnowski, P.; Sikorski, L.; Ziemianski, A.

    1993-01-01

    A case of the left diaphragmatic hernia due to blunt thoracic and abdominal trauma is presented. Characteristic radiological signs of splenic translocation into the thorax contributed to quick diagnosis and immediate surgical intervention. (author)

  9. Biomechanical simulation of thorax deformation using finite element approach.

    Science.gov (United States)

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

    2016-02-06

    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. We constructed a finite element model of the thorax, including the rib cage, intercostal muscles, and diaphragm. To reproduce the muscle contractions, we introduced the Hill-type transversely isotropic hyperelastic continuum skeletal muscle model, which allows the intercostal muscles and diaphragm to contract along the direction of the fibres with clinically measurable muscle activation and active force-length relationship. The anatomical fibre orientations of the intercostal muscles and diaphragm were introduced. Thorax deformation consists of movements of the ribs and diaphragm. By activating muscles, we were able to reproduce the pump-handle and bucket-handle motions for the ribs and the clinically observed motion for the diaphragm. In order to confirm the effectiveness of this approach, we simulated the thorax deformation during normal quiet breathing and compared the results with four-dimensional computed tomography (4D-CT) images for verification. Thorax deformation can be simulated by modelling the respiratory muscles according to continuum mechanics and by introducing muscle contractions. The reproduction of representative motions of the ribs and diaphragm and the comparison of the thorax deformations during normal quiet breathing with 4D-CT images demonstrated the effectiveness of the proposed approach. This work may provide a platform for establishing a computational mechanics model of the human respiratory system.

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

    NARCIS (Netherlands)

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

    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

  11. Anthropomorphic Phantom Radiation Dosimetry at the NATO Standard Reference Point at Aberdeen Proving Ground,

    Science.gov (United States)

    1987-04-01

    Project, a series of experiments were conducted at Aberdeen Proving Ground in September 1986 in order to determine neutron and gamma-ray doses... osseuse et les paramitres qui pourraient amoindria le rendement d’un soldat. 4 U’ .1 * ’ - , - . " .’ -" " z " w...than 1% by mass) but offered no numerical data to back up this claim. Accordingly, DREO had a chemical analysis conducted by Guelph Chemical

  12. An anthropomorphic phantom study of visualisation of surgical clips for partial breast irradiation (PBI) setup verification

    International Nuclear Information System (INIS)

    Thomas, Carys W.; Nichol, Alan M.; Park, Julie E.; Hui, Jason F.; Giddings, Alison A.; Grahame, Sheri; Otto, Karl

    2009-01-01

    Surgical clips were investigated for partial breast image-guided radiotherapy (IGRT). Small titanium clips were insufficiently well visualised. Medium tantalum clips were best for megavoltage IGRT and small tantalum clips were best for floor mounted kilovoltage IGRT (ExacTrac TM ). Both small tantalum and medium titanium clips were suitable for isocentric kilovoltage IGRT

  13. 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

  14. An anthropomorphic phantom study of visualisation of surgical clips for partial breast irradiation (PBI) setup verification.

    Science.gov (United States)

    Thomas, Carys W; Nichol, Alan M; Park, Julie E; Hui, Jason F; Giddings, Alison A; Grahame, Sheri; Otto, Karl

    2009-01-01

    Surgical clips were investigated for partial breast image-guided radiotherapy (IGRT). Small titanium clips were insufficiently well visualised. Medium tantalum clips were best for megavoltage IGRT and small tantalum clips were best for floor mounted kilovoltage IGRT (ExacTrac). Both small tantalum and medium titanium clips were suitable for isocentric kilovoltage IGRT.

  15. Radiation dose evaluation in 64-slice CT examinations with adult and paediatric anthropomorphic phantoms

    OpenAIRE

    Fujii, K; Aoyama, T; Yamauchi-Kawaura, C; Koyama, S; Yamauchi, M; Ko, S; Akahane, K; Nishizawa, K

    2009-01-01

    The objective of this study was to evaluate the organ dose and effective dose to patients undergoing routine adult and paediatric CT examinations with 64-slice CT scanners and to compare the doses with those from 4-, 8- and 16-multislice CT scanners. Patient doses were measured with small (

  16. Computational hybrid anthropometric paediatric phantom library for internal radiation dosimetry

    Science.gov (United States)

    Xie, Tianwu; Kuster, Niels; Zaidi, Habib

    2017-04-01

    Hybrid computational phantoms combine voxel-based and simplified equation-based modelling approaches to provide unique advantages and more realism for the construction of anthropomorphic models. In this work, a methodology and C++ code are developed to generate hybrid computational phantoms covering statistical distributions of body morphometry in the paediatric population. The paediatric phantoms of the Virtual Population Series (IT’IS Foundation, Switzerland) were modified to match target anthropometric parameters, including body mass, body length, standing height and sitting height/stature ratio, determined from reference databases of the National Centre for Health Statistics and the National Health and Nutrition Examination Survey. The phantoms were selected as representative anchor phantoms for the newborn, 1, 2, 5, 10 and 15 years-old children, and were subsequently remodelled to create 1100 female and male phantoms with 10th, 25th, 50th, 75th and 90th body morphometries. Evaluation was performed qualitatively using 3D visualization and quantitatively by analysing internal organ masses. Overall, the newly generated phantoms appear very reasonable and representative of the main characteristics of the paediatric population at various ages and for different genders, body sizes and sitting stature ratios. The mass of internal organs increases with height and body mass. The comparison of organ masses of the heart, kidney, liver, lung and spleen with published autopsy and ICRP reference data for children demonstrated that they follow the same trend when correlated with age. The constructed hybrid computational phantom library opens up the prospect of comprehensive radiation dosimetry calculations and risk assessment for the paediatric population of different age groups and diverse anthropometric parameters.

  17. Morphology and functional anatomy of the growing thorax; Morphologie und funktionelle Anatomie des wachsenden Thorax

    Energy Technology Data Exchange (ETDEWEB)

    Weninger, W.J.; Meng, S.; Geyer, S.H.; Weninger, S.U.G. [Integrative Morphology Group, Unversitaet Wien (Austria); Institut fuer Anatomie, Universitaet Wien (Austria)

    2003-12-01

    Morphogenesis of most thoracic organs and structures is not finished with birth but perpetuates in postnatal life. The postnatal growth is partly associated with enormous changes in structure, morphology, and function. Our study presents an overview of morphological, topological and functional peculiarities of thoracic anatomy during infancy, childhood and adolescence. It focuses on the development of the mammary gland, osseous structures of the chest wall, thymus, heart, and lungs. Most of the presented data are based on post-mortem studies. Measurements and numerical data are mainly included for illustration of growth-associated changes. (orig.) [German] Die Morphogenese mancher thorakaler Strukturen und Organe ist zum Zeitpunkt der Geburt noch nicht vollstaendig abgeschlossen. Ihr postpartales Wachstum geht mit teils enormen strukturellen, morphologischen und funktionellen Veraenderungen einher. Die hier praesentierte Arbeit gibt einen Ueberblick ueber morphologische, topologische und funktionelle Besonderheiten der Anatomie des Thorax und seiner Organe im Neonatus, Saeugling, Kind und Jugendlichen. Der Schwerpunkt liegt auf der Beschreibung der Entwicklung der Brustdruese, des knoechernen Thorax, des Thymus, des Herzen und der Lunge. Die vorgestellten Daten stammen grossteils aus Post-mortem-Studien und dienen vorwiegend dazu, das Ausmass wachstumsassoziierter Veraenderungen und Relationen zu illustrieren. (orig.)

  18. Accuracy of a commercial optical 3D surface imaging system for realignment of patients for radiotherapy of the thorax

    Energy Technology Data Exchange (ETDEWEB)

    Schoeffel, Philipp J [German Cancer Research Center (DKFZ), Department of Medical Physics in Radiation Oncology, Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Harms, Wolfgang [Radiological University Clinic Heidelberg, Department of Radiation Oncology and Radiation Therapy, Im Neuenheimer Feld 400, 69120 Heidelberg (Germany); Sroka-Perez, Gabriele [Radiological University Clinic Heidelberg, Department of Radiation Oncology and Radiation Therapy, Im Neuenheimer Feld 400, 69120 Heidelberg (Germany); Schlegel, Wolfgang [German Cancer Research Center (DKFZ), Department of Medical Physics in Radiation Oncology, Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Karger, Christian P [German Cancer Research Center (DKFZ), Department of Medical Physics in Radiation Oncology, Im Neuenheimer Feld 280, 69120 Heidelberg (Germany)

    2007-07-07

    Accurate and reproducible patient setup is a prerequisite to fractionated radiotherapy. To evaluate the applicability and technical performance of a commercial 3D surface imaging system for repositioning of breast cancer patients, measurements were performed in a rigid anthropomorphic phantom as well as in healthy volunteers. The camera system records a respiration-gated surface model of the imaged object, which may be registered to a previously recorded reference model. A transformation is provided, which may be applied to the treatment couch to correct the setup of the patient. The system showed a high stability and detected pre-defined shifts of phantoms and healthy volunteers with an accuracy of 0.40 {+-} 0.26 mm and 1.02 {+-} 0.51 mm, respectively (spatial deviation between pre-defined shift and suggested correction). The accuracy of the suggested rotational correction around the vertical axis was always better than 0.3{sup 0} in phantom measurements and 0.8{sup 0} in volunteers, respectively. Comparison of the suggested setup correction with that detected by a second and independently operated marker-based optical system provided consistent results. The results demonstrate that the camera system provides highly accurate setup corrections in a phantom and healthy volunteers. The most efficient use of the system for improving the setup accuracy in breast cancer patients has to be investigated in routine patient treatments.

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

    International Nuclear Information System (INIS)

    Velo, Alexandre F.; Miranda, Jose Ricardo A.

    2013-01-01

    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

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

    International Nuclear Information System (INIS)

    Ehler, E; Higgins, P; Dusenbery, K

    2014-01-01

    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

  1. 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.

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

    Science.gov (United States)

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

    2014-11-21

    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.

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

    International Nuclear Information System (INIS)

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

    2014-01-01

    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. (paper)

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

    International Nuclear Information System (INIS)

    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(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

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

    International Nuclear Information System (INIS)

    Olsher, R. H.; Van Riper, K. A.

    2005-01-01

    In typical realistic scenarios, dose factors due to 60 Co 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)

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

    International Nuclear Information System (INIS)

    Martins, Maximiano C.; Santos, Denison S.; Queiroz Filho, Pedro P. de; Begalli, Marcia

    2009-01-01

    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 125 I 2301 model for low dose rate and the Amersham Buchler G0814 model 192 Ir 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)

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

    International Nuclear Information System (INIS)

    Ehler, E; Higgins, P; Dusenbery, K

    2014-01-01

    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

  8. 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

  9. 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

    2016-02-07

    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 [Formula: see text] 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 [Formula: see text] depending on the environmental material was established. The Monte Carlo simulation show, that there is only a small dependence of [Formula: see text] 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.

  10. 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.

  11. Social Cognition Unbound: Insights Into Anthropomorphism and Dehumanization.

    Science.gov (United States)

    Waytz, Adam; Epley, Nicholas; Cacioppo, John T

    2010-02-01

    People conceive of wrathful gods, fickle computers, and selfish genes, attributing human characteristics to a variety of supernatural, technological, and biological agents. This tendency to anthropomorphize nonhuman agents figures prominently in domains ranging from religion to marketing to computer science. Perceiving an agent to be humanlike has important implications for whether the agent is capable of social influence, accountable for its actions, and worthy of moral care and consideration. Three primary factors-elicited agent knowledge, sociality motivation, and effectance motivation-appear to account for a significant amount of variability in anthropomorphism. Identifying these factors that lead people to see nonhuman agents as humanlike also sheds light on the inverse process of dehumanization, whereby people treat human agents as animals or objects. Understanding anthropomorphism can contribute to a more expansive view of social cognition that applies social psychological theory to a wide variety of both human and nonhuman agents.

  12. 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

  13. Anthropomorphism in Human-Robot Co-evolution.

    Science.gov (United States)

    Damiano, Luisa; Dumouchel, Paul

    2018-01-01

    Social robotics entertains a particular relationship with anthropomorphism, which it neither sees as a cognitive error, nor as a sign of immaturity. Rather it considers that this common human tendency, which is hypothesized to have evolved because it favored cooperation among early humans, can be used today to facilitate social interactions between humans and a new type of cooperative and interactive agents - social robots. This approach leads social robotics to focus research on the engineering of robots that activate anthropomorphic projections in users. The objective is to give robots "social presence" and "social behaviors" that are sufficiently credible for human users to engage in comfortable and potentially long-lasting relations with these machines. This choice of 'applied anthropomorphism' as a research methodology exposes the artifacts produced by social robotics to ethical condemnation: social robots are judged to be a "cheating" technology, as they generate in users the illusion of reciprocal social and affective relations. This article takes position in this debate, not only developing a series of arguments relevant to philosophy of mind, cognitive sciences, and robotic AI, but also asking what social robotics can teach us about anthropomorphism. On this basis, we propose a theoretical perspective that characterizes anthropomorphism as a basic mechanism of interaction, and rebuts the ethical reflections that a priori condemns "anthropomorphism-based" social robots. To address the relevant ethical issues, we promote a critical experimentally based ethical approach to social robotics, "synthetic ethics," which aims at allowing humans to use social robots for two main goals: self-knowledge and moral growth.

  14. MO-FG-209-05: Towards a Feature-Based Anthropomorphic Model Observer

    Energy Technology Data Exchange (ETDEWEB)

    Avanaki, A.

    2016-06-15

    This symposium will review recent advances in the simulation methods for evaluation of novel breast imaging systems – the subject of AAPM Task Group TG234. Our focus will be on the various approaches to development and validation of software anthropomorphic phantoms and their use in the statistical assessment of novel imaging systems using such phantoms along with computational models for the x-ray image formation process. Due to the dynamic development and complex design of modern medical imaging systems, the simulation of anatomical structures, image acquisition modalities, and the image perception and analysis offers substantial benefits of reduced cost, duration, and radiation exposure, as well as the known ground-truth and wide variability in simulated anatomies. For these reasons, Virtual Clinical Trials (VCTs) have been increasingly accepted as a viable tool for preclinical assessment of x-ray and other breast imaging methods. Activities of TG234 have encompassed the optimization of protocols for simulation studies, including phantom specifications, the simulated data representation, models of the imaging process, and statistical assessment of simulated images. The symposium will discuss the state-of-the-science of VCTs for novel breast imaging systems, emphasizing recent developments and future directions. Presentations will discuss virtual phantoms for intermodality breast imaging performance comparisons, extension of the breast anatomy simulation to the cellular level, optimized integration of the simulated imaging chain, and the novel directions in the observer models design. Learning Objectives: Review novel results in developing and applying virtual phantoms for inter-modality breast imaging performance comparisons; Discuss the efforts to extend the computer simulation of breast anatomy and pathology to the cellular level; Summarize the state of the science in optimized integration of modules in the simulated imaging chain; Compare novel directions

  15. Extraskeletal osteosarcoma of the thorax in a goat: case report

    Directory of Open Access Journals (Sweden)

    Becker-Birck Mareike

    2011-09-01

    Full Text Available Abstract Background This report describes the results of clinical, ultrasonographic and computed tomographic examination of a 16-year-old goat with extraskeletal osteosarcoma of the thorax. Case presentation The lead clinical signs were abnormal condition and demeanour, fever, tachycardia, tachypnoea, dyspnoea and dilated jugular veins. Ultrasonographic examination of the thorax revealed a precardial mass, measuring 16.4 by 11.4 by 14.2 cm. Computed tomographic examination showed dorsocaudal displacement of the trachea, heart and lungs to the right. A tentative diagnosis of mediastinal or pleural neoplasia was made, and the goat was euthanased and necropsied. A definitive diagnosis was based on histological examination of the mass. Conclusions To our knowledge, this case report is the first description of extraskeletal osteosarcoma of the thorax in goats and serves to broaden the diagnostic spectrum of thoracic diseases in this species. Extraskeletal osteosarcoma should be part of the differential diagnosis in goats with thoracic tumours.

  16. Assessment of image quality of 64-row Dual Source versus Single Source CT coronary angiography on heart rate : A phantom study

    NARCIS (Netherlands)

    Dikkers, R.; Greuter, M. J. W.; Kristanto, W.; van Ooijen, P. M. A.; Sijens, P. E.; Willems, T. P.; Oudkerk, M.

    Purpose: To assess the influence of temporal resolution on image quality of computed tomographic (CT) coronary angiography by comparing 64-row Dual Source CT (DSCT) and Single Source CT (SSCT) at different heart rates. Methods: An anthropomorphic moving heart phantom was scanned at rest, and at 50

  17. A further investigation of the centroid-to-centroid method for stereotactic lung radiotherapy: A phantom study

    International Nuclear Information System (INIS)

    Lu, Bo; Samant, Sanjiv; Mittauer, Kathryn; Lee, Soyoung; Huang, Yin; Li, Jonathan; Kahler, Darren; Liu, Chihray

    2013-01-01

    Purpose: Our previous study [B. Lu et al., “A patient alignment solution for lung SBRT setups based on a deformable registration technique,” Med. Phys. 39(12), 7379–7389 (2012)] proposed a deformable-registration-based patient setup strategy called the centroid-to-centroid (CTC) method, which can perform an accurate alignment of internal-target-volume (ITV) centroids between averaged four-dimensional computed tomography and cone-beam computed tomography (CBCT) images. Scenarios with variations between CBCT and simulation CT caused by irregular breathing and/or tumor change were not specifically considered in the patient study [B. Lu et al., “A patient alignment solution for lung SBRT setups based on a deformable registration technique,” Med. Phys. 39(12), 7379–7389 (2012)] due to the lack of both a sufficiently large patient data sample and a method of tumor tracking. The aim of this study is to thoroughly investigate and compare the impacts of breathing pattern and tumor change on both the CTC and the translation-only (T-only) gray-value mode strategies by employing a four-dimensional (4D) lung phantom.Methods: A sophisticated anthropomorphic 4D phantom (CIRS Dynamic Thorax Phantom model 008) was employed to simulate all desired respiratory variations. The variation scenarios were classified into four groups: inspiration to expiration ratio (IE ratio) change, tumor trajectory change, tumor position change, tumor size change, and the combination of these changes. For each category the authors designed several scenarios to demonstrate the effects of different levels of breathing variation on both of the T-only and the CTC methods. Each scenario utilized 4DCT and CBCT scans. The ITV centroid alignment discrepancies for CTC and T-only were evaluated. The dose-volume-histograms (DVHs) of ITVs for two extreme cases were analyzed.Results: Except for some extreme cases in the combined group, the accuracy of the CTC registration was about 2 mm for all cases for

  18. Validation of CT brain perfusion methods using a realistic dynamic head phantom.

    Science.gov (United States)

    Riordan, Alan J; Prokop, Mathias; Viergever, Max A; Dankbaar, Jan Willem; Smit, Ewoud J; de Jong, Hugo W A M

    2011-06-01

    Development and evaluation of a realistic hybrid head phantom for the validation of quantitative CT brain perfusion methods. A combination, or hybrid, of CT images of an anthropomorphic head phantom together with clinically acquired MRI brain images was used to construct a dynamic hybrid head phantom. Essential CT imaging parameters such as spatially dependent noise, effects of resolution, tube settings, and reconstruction parameters were intrinsically included by scanning a skull phantom using CT perfusion (CTP) protocols with varying mAs. These data were combined with processed high resolution 7T clinical MRI images to include healthy and diseased brain parenchyma, as well as the cerebral vascular system. Time attenuation curves emulating contrast bolus passage based on perfusion as observed in clinical studies were added. Using the phantom, CTP images were generated using three brain perfusion calculation methods: bcSVD, sSVD, and fit-based deconvolution, and the linearity and accuracy of the three calculation methods was assessed. Dependency of perfusion outcome on calculation method was compared to clinical data. Furthermore, the potential of the phantom to optimize brain perfusion packages was investigated. All perfusion calculation methods showed overestimation of low perfusion values and underestimation of high perfusion values. Good correlation in behavior between phantom and clinical data was found (R2 = 0.84). A dynamic hybrid head phantom constructed from CT and MRI data was demonstrated to realistically represent clinical CTP studies, which is useful for assessing CT brain perfusion acquisition, reconstruction, and analysis.

  19. The UF series of tomographic computational phantoms of pediatric patients

    International Nuclear Information System (INIS)

    Lee, Choonik; Williams, Jonathan L.; Lee, Choonsik; Bolch, Wesley E.

    2005-01-01

    Two classes of anthropomorphic computational phantoms exist for use in Monte Carlo radiation transport simulations: tomographic voxel phantoms based upon three-dimensional (3D) medical images, and stylized mathematical phantoms based upon 3D surface equations for internal organ definition. Tomographic phantoms have shown distinct advantages over the stylized phantoms regarding their similarity to real human anatomy. However, while a number of adult tomographic phantoms have been developed since the early 1990s, very few pediatric tomographic phantoms are presently available to support dosimetry in pediatric diagnostic and therapy examinations. As part of a larger effort to construct a series of tomographic phantoms of pediatric patients, five phantoms of different ages (9-month male, 4-year female, 8-year female, 11-year male, and 14-year male) have been constructed from computed tomography (CT) image data of live patients using an IDL-based image segmentation tool. Lungs, bones, and adipose tissue were automatically segmented through use of window leveling of the original CT numbers. Additional organs were segmented either semiautomatically or manually with the aid of both anatomical knowledge and available image-processing techniques. Layers of skin were created by adding voxels along the exterior contour of the bodies. The phantoms were created from fused images taken from head and chest-abdomen-pelvis CT exams of the same individuals (9-month and 4-year phantoms) or of two different individuals of the same sex and similar age (8-year, 11-year, and 14-year phantoms). For each model, the resolution and slice positions of the image sets were adjusted based upon their anatomical coverage and then fused to a single head-torso image set. The resolutions of the phantoms for the 9-month, 4-year, 8-year, 11-year, and 14-year are 0.43x0.43x3.0 mm, 0.45x0.45x5.0 mm, 0.58x0.58x6.0 mm, 0.47x0.47x6.00 mm, and 0.625x0.625x6.0 mm, respectively. While organ masses can be

  20. A phantom study of the accuracy of CT, MR and PET image registrations with a block matching-based algorithm.

    Science.gov (United States)

    Isambert, A; Bonniaud, G; Lavielle, F; Malandain, G; Lefkopoulos, D

    2008-12-01

    The aim of the present study was to quantitatively assess the performance of a block matching-based automatic registration algorithm integrated within the commercial treatment planning system designated ISOgray from Dosisoft. The accuracy of the process was evaluated by a phantom study on computed tomography (CT), magnetic resonance (MR) and positron emission tomography (PET) images. Two phantoms were used to carry out this study: the cylindrical Jaszczak phantom and the anthropomorphic Liqui-Phil Head Phantom (the Phantom Laboratory), containing fillable spheres. External fiducial markers were used to quantify the accuracy of 41 CT/CT, MR/CT and PET/CT automatic registrations with images of the rotated and tilted phantoms. The study first showed that a cylindrical phantom was not adapted for the evaluation of the performance of a block matching-based registration software. Secondly, the Liqui-Phil Head Phantom study showed that the algorithm was able to perform automatic registrations of CT/CT and MR/CT images with differences of up to 40 degrees in phantom rotation and of up to 20-30 degrees for PET/CT with accuracy below the image voxel size. The study showed that the block matching-based automatic registration software under investigation was robust, reliable and yielded very satisfactory results. This phantom-based test can be integrated into a periodical quality assurance process and used for any commissioning of image registration software for radiation therapy.

  1. Three-dimensional printer-generated patient-specific phantom for artificial in vivo dosimetry in radiotherapy quality assurance.

    Science.gov (United States)

    Kamomae, Takeshi; Shimizu, Hidetoshi; Nakaya, Takayoshi; Okudaira, Kuniyasu; Aoyama, Takahiro; Oguchi, Hiroshi; Komori, Masataka; Kawamura, Mariko; Ohtakara, Kazuhiro; Monzen, Hajime; Itoh, Yoshiyuki; Naganawa, Shinji

    2017-12-01

    Pretreatment intensity-modulated radiotherapy quality assurance is performed using simple rectangular or cylindrical phantoms; thus, the dosimetric errors caused by complex patient-specific anatomy are absent in the evaluation objects. In this study, we construct a system for generating patient-specific three-dimensional (3D)-printed phantoms for radiotherapy dosimetry. An anthropomorphic head phantom containing the bone and hollow of the paranasal sinus is scanned by computed tomography (CT). Based on surface rendering data, a patient-specific phantom is formed using a fused-deposition-modeling-based 3D printer, with a polylactic acid filament as the printing material. Radiophotoluminescence glass dosimeters can be inserted in the 3D-printed phantom. The phantom shape, CT value, and absorbed doses are compared between the actual and 3D-printed phantoms. The shape difference between the actual and printed phantoms is less than 1 mm except in the bottom surface region. The average CT value of the infill region in the 3D-printed phantom is -6 ± 18 Hounsfield units (HU) and that of the vertical shell region is 126 ± 18 HU. When the same plans were irradiated, the dose differences were generally less than 2%. These results demonstrate the feasibility of the 3D-printed phantom for artificial in vivo dosimetry in radiotherapy quality assurance. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  2. Phantom dosimetry at 15 MV conformal radiation therapy

    International Nuclear Information System (INIS)

    Thompson, Larissa; Campos, Tarcisio P.R.

    2015-01-01

    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)

  3. Phantom dosimetry at 15 MV conformal radiation therapy

    International Nuclear Information System (INIS)

    Thompson, Larissa; Campos, Tarcisio P.R.; Dias, Humberto G.

    2013-01-01

    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)

  4. 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)

  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. Evolution of water equivalent phantoms

    International Nuclear Information System (INIS)

    Yabutani, Toshimine; Ida, Yoshihiro; Sawada, Takeshi

    1998-01-01

    In radiation therapy, the dose absorbed by the target tissue needs to be extremely accurate. In order to obtain the target absorbed dose, radiation dose measurements are performed using a phantom instead of the patient's body, because the target absorbed dose cannot be directly measured. Although water is the best human muscle equivalent phantom, it is not useful for this purpose. Therefore, water equivalent solid phantoms are usually used for the measurements. We compared the following water equivalent solid phantoms for water: Tough water phantom, 457 Solid water phantom, RW-3, Mix-DP, polystyrene resin, polyethylene resin, and acrylic resin. The measurements obtained were ionization current in the phantoms as determined by ionization chamber, tissue-maximum ratio, transmission measurements in water with and without the phantoms, Hounsfield units of the phantoms for uniformity of inside phantoms as determined by computed tomography, and accuracy of the phantoms. Results showed the phantoms to be almost equivalent to water, except for the acrylic resin phantom. However, the phantoms had various characteristics that affected accuracy, and the phantoms underwent change with time. Measurement error was caused by the characteristics of the phantoms. Therefore, it is important to measure the calibration coefficient of phantoms for water, regardless of what is stated on paper. (author)

  7. Computer Control Of Coordinate Movement With Anthropomorphic Two-Arms

    Science.gov (United States)

    Hsiao-tsu, Chang; Bai-yan, Shi

    1985-01-01

    The paper explores the mutual collision problem for two moving anthropomorphic arms with complicatedly shaped objects grasped each in the case constant acceleration in three dimensional space. A discriminant criterion has been proposed for intersection detection, which is based on topology theory. This method is more expressive and straightforward.

  8. Anthropomorphic Patterns And Smoking In A Nigerian Population ...

    African Journals Online (AJOL)

    ... codes for tallness in men also encode male craving for tobacco. For tobacco smoking, which is implicated in many health hazards, male tallness may probably be the only health benefit. Key words: Tobacco smoking, males, females, anthropomorphic measurements. Journal of Experimental and Clinical Anatomy Vol.

  9. Modeling the Biodynamical Response of the Human Thorax With Body Armor From a Bullet Impact

    National Research Council Canada - National Science Library

    Lobuono, John

    2001-01-01

    The objective of this study is to develop a finite element model of the human thorax with a protective body armor system so that the model can adequately determine the thorax's biodynamical response...

  10. Modeling the Biodynamical Response of the Human Thorax with Body Armor from a Bullet Impact

    National Research Council Canada - National Science Library

    Lobuono, John

    2001-01-01

    The objective of this study is to develop a finite element model of the human thorax with a protective body armor system so that the model can adequately determine the thorax's biodynamical response...

  11. Training for thorax diagnostics. Systematic cardiopulmonary image analysis

    International Nuclear Information System (INIS)

    Kirchner, Johannes

    2010-01-01

    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.

  12. Impact Analysis of a Biomechanical Model of the Human Thorax

    National Research Council Canada - National Science Library

    Jolly, Johannes

    2000-01-01

    .... The objective of the study was to create a viable finite element model of the human thorax. This objective was accomplished through the construction of a three-dimensional finite element model in DYNA3D, a finite element analysis program...

  13. Phantom limb pain

    Science.gov (United States)

    ... limb is still there. This is called phantom sensation. You may feel: Pain in your limb even though it is physically not there Tingly Prickly Numb Hot or cold Like your missing toes or fingers are moving ...

  14. 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.

  15. Anthropomorphism in Human–Robot Co-evolution

    Directory of Open Access Journals (Sweden)

    Luisa Damiano

    2018-03-01

    Full Text Available Social robotics entertains a particular relationship with anthropomorphism, which it neither sees as a cognitive error, nor as a sign of immaturity. Rather it considers that this common human tendency, which is hypothesized to have evolved because it favored cooperation among early humans, can be used today to facilitate social interactions between humans and a new type of cooperative and interactive agents – social robots. This approach leads social robotics to focus research on the engineering of robots that activate anthropomorphic projections in users. The objective is to give robots “social presence” and “social behaviors” that are sufficiently credible for human users to engage in comfortable and potentially long-lasting relations with these machines. This choice of ‘applied anthropomorphism’ as a research methodology exposes the artifacts produced by social robotics to ethical condemnation: social robots are judged to be a “cheating” technology, as they generate in users the illusion of reciprocal social and affective relations. This article takes position in this debate, not only developing a series of arguments relevant to philosophy of mind, cognitive sciences, and robotic AI, but also asking what social robotics can teach us about anthropomorphism. On this basis, we propose a theoretical perspective that characterizes anthropomorphism as a basic mechanism of interaction, and rebuts the ethical reflections that a priori condemns “anthropomorphism-based” social robots. To address the relevant ethical issues, we promote a critical experimentally based ethical approach to social robotics, “synthetic ethics,” which aims at allowing humans to use social robots for two main goals: self-knowledge and moral growth.

  16. Anthropomorphism in Human–Robot Co-evolution

    Science.gov (United States)

    Damiano, Luisa; Dumouchel, Paul

    2018-01-01

    Social robotics entertains a particular relationship with anthropomorphism, which it neither sees as a cognitive error, nor as a sign of immaturity. Rather it considers that this common human tendency, which is hypothesized to have evolved because it favored cooperation among early humans, can be used today to facilitate social interactions between humans and a new type of cooperative and interactive agents – social robots. This approach leads social robotics to focus research on the engineering of robots that activate anthropomorphic projections in users. The objective is to give robots “social presence” and “social behaviors” that are sufficiently credible for human users to engage in comfortable and potentially long-lasting relations with these machines. This choice of ‘applied anthropomorphism’ as a research methodology exposes the artifacts produced by social robotics to ethical condemnation: social robots are judged to be a “cheating” technology, as they generate in users the illusion of reciprocal social and affective relations. This article takes position in this debate, not only developing a series of arguments relevant to philosophy of mind, cognitive sciences, and robotic AI, but also asking what social robotics can teach us about anthropomorphism. On this basis, we propose a theoretical perspective that characterizes anthropomorphism as a basic mechanism of interaction, and rebuts the ethical reflections that a priori condemns “anthropomorphism-based” social robots. To address the relevant ethical issues, we promote a critical experimentally based ethical approach to social robotics, “synthetic ethics,” which aims at allowing humans to use social robots for two main goals: self-knowledge and moral growth. PMID:29632507

  17. 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)

  18. 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.

  19. Design of a head phantom produced on a 3D rapid prototyping printer and comparison with a RANDO and 3M lucite head phantom in eye dosimetry applications.

    Science.gov (United States)

    Homolka, Peter; Figl, Michael; Wartak, Andreas; Glanzer, Mathias; Dünkelmeyer, Martina; Hojreh, Azadeh; Hummel, Johann

    2017-04-21

    An anthropomorphic head phantom including eye inserts allowing placement of TLDs 3 mm below the cornea has been produced on a 3D printer using a photo-cured acrylic resin to best allow tissue equivalence. Thus H p (3) can be determined in radiological and interventional photon radiation fields. Eye doses and doses to the forehead have been compared to an Alderson RANDO head and a 3M Lucite skull phantom in terms of surface dose per incident air kerma for frontal irradiation since the commercial phantoms do not allow placement of TLDs 3 mm below the corneal surface. A comparison of dose reduction factors (DRFs) of a common lead glasses model has also been performed. Eye dose per incident air kerma were comparable between all three phantoms (printed phantom: 1.40, standard error (SE) 0.04; RANDO: 1.36, SE 0.03; 3M: 1.37, SE 0.03). Doses to the forehead were identical to eye surface doses for the printed phantom and the RANDO head (ratio 1.00 SE 0.04, and 0.99 SE 0.03, respectively). In the 3M Lucite skull phantom dose on the forehead was 15% lower than dose to the eyes attributable to phantom properties. DRF of a sport frame style leaded glasses model with 0.75 mm lead equivalence measured were 6.8 SE 0.5, 9.3 SE 0.4 and 10.5 SE 0.5 for the RANDO head, the printed phantom, and the 3M Lucite head phantom, respectively, for frontal irradiation. A comparison of doses measured in 3 mm depth and on the surface of the eyes in the printed phantom revealed no difference larger than standard errors from TLD dosimetry. 3D printing offers an interesting opportunity for phantom design with increasing potential as printers allowing combinations of tissue substitutes will become available. Variations between phantoms may provide a useful indication of uncertainty budgets when using phantom measurements to estimate individual personnel doses.

  20. Effects of body habitus on internal radiation dose calculations using the 5-year-old anthropomorphic male models

    Science.gov (United States)

    Xie, Tianwu; Kuster, Niels; Zaidi, Habib

    2017-08-01

    Computational phantoms are commonly used in internal radiation dosimetry to assess the amount and distribution pattern of energy deposited in various parts of the human body from different internal radiation sources. Radiation dose assessments are commonly performed on predetermined reference computational phantoms while the argument for individualized patient-specific radiation dosimetry exists. This study aims to evaluate the influence of body habitus on internal dosimetry and to quantify the uncertainties in dose estimation correlated with the use of fixed reference models. The 5-year-old IT’IS male phantom was modified to match target anthropometric parameters, including body weight, body height and sitting height/stature ratio (SSR), determined from reference databases, thus enabling the creation of 125 5-year-old habitus-dependent male phantoms with 10th, 25th, 50th, 75th and 90th percentile body morphometries. We evaluated the absorbed fractions and the mean absorbed dose to the target region per unit cumulative activity in the source region (S-values) of F-18 in 46 source regions for the generated 125 anthropomorphic 5-year-old hybrid male phantoms using the Monte Carlo N-Particle eXtended general purpose Monte Carlo transport code and calculated the absorbed dose and effective dose of five 18F-labelled radiotracers for children of various habitus. For most organs, the S-value of F-18 presents stronger statistical correlations with body weight, standing height and sitting height than BMI and SSR. The self-absorbed fraction and self-absorbed S-values of F-18 and the absorbed dose and effective dose of 18F-labelled radiotracers present with the strongest statistical correlations with body weight. For 18F-Amino acids, 18F-Brain receptor substances, 18F-FDG, 18F-L-DOPA and 18F-FBPA, the mean absolute effective dose differences between phantoms of different habitus and fixed reference models are 11.4%, 11.3%, 10.8%, 13.3% and 11.4%, respectively. Total body

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

    International Nuclear Information System (INIS)

    Biju, K.

    2012-01-01

    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 192 Ir source and BEBIG 60 Co 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. A software to edit voxel phantoms and to calculate conversion coefficients for radiation protection

    International Nuclear Information System (INIS)

    Vieira, J.W.; Stosic, B.; Lima, F.R.A.; Kramer, R.; Santos, A.M.; Lima, V.J.M.

    2005-01-01

    The MAX and FAX phantoms have been developed based on a male and female, respectively, adult body from ICRP and coupled to the Monte Carlo code (EGS4). These phantoms permit the calculating of the equivalent dose in organs and tissues of the human body for the radiation protection purposes . In the constructing of these anthropomorphic models, the software developed called FANTOMAS, which performs tasks as file format conversion, filtering 2D and 3D images, exchange of identifying numbers of organs, body mass adjustments based in volume, resampling of 2D and 3D images, resize images, preview consecutive slices of the phantom, running computational models of exposure FANTOMA/EGS4 and viewing graphics of conversion factors between equivalent dose and a measurable dosimetric quantity. This paper presents the main abilities of FANTOMAS and uses the MAX and/or FAX to exemplify some procedures

  3. 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.

  4. 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

    International Nuclear Information System (INIS)

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

    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

  5. The X-ray intensity pattern in a radiograph of the thorax

    International Nuclear Information System (INIS)

    Hoeschen, C.; Buhr, E.; Doehring, W.

    2000-01-01

    At present digital detectors for diagnostic X-ray imaging become more and more important. The image quality provided by these detector systems does not only depend on the properties of the systems but also in the X-ray intensity pattern in the detector plane. This pattern for a radiograph of the thorax was measured with high spatial resolution. This was done by exposing a specially prepared phantom of the lung to X-rays applying the standard examination conditions for thoracic imaging. The X-ray images were stored on industrial X-ray film generally used for non-destructive testing. These images were digitised with a high-resolution drum film scanner. The scanner and the film were able to reproduce the information in the pattern in the range of spatial frequencies up to 15 mm -1 and there were no problems with aliasing due to the scanning process. Using the characteristic curves of the film and the scanner the X-ray intensity pattern was calculated. A new method to evaluate the information content of the X-ray intensity pattern in the frequency domain was developed. The results of this evaluation were used to propose a requirement for digital detector system to have a sampling interval less than 100 μm. (orig.) [de

  6. Modeling and control of an anthropomorphic robotic hand

    OpenAIRE

    Bensalah, Choukri

    2016-01-01

    Mención Europea en el título de doctor This thesis presents methods and tools for enabling the successful use of robotic hands. For highly dexterous and/or anthropomorphic robotic hands, these methods have to share some common goals, such as overcoming the potential complexity of the mechanical design and the ability of performing accurate tasks with low and efficient computational cost. A prerequisite for dexterity is to increase the workspace of the robotic hand. For th...

  7. Patayan Anthropomorphic Figurines from an Orange County Site

    OpenAIRE

    Koerper, Henry C; Hedges, Ken

    1996-01-01

    The primary purpose of this study is to describe these specimens and discuss their cultural associations, temporal placement, and the possible agents and routes of trade for the exotic effigies. Set against the near absence of Late Prehistoric anthropomorphic figurines from elsewhere in Orange County, these dozen artifacts, as well as figurines of the Northern Tradition found at CA-ORA-58, have important implications for the political and economic role of the Banning-Norris site, as well as i...

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

    International Nuclear Information System (INIS)

    Klein, H.J.; Offeney, F.

    1990-01-01

    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) [de

  9. Thorax computed tomography findings in patients victims of chest trauma

    Directory of Open Access Journals (Sweden)

    Francisco Jose Rodrigues de Moura Filho

    2015-12-01

    Full Text Available Objective: To describe thorax computed tomography findings in patients assisted in the emergency unit of Institute Dr Jose Frota (IJF. Materials and Methods: Descriptive study analyzing 160 consecutive contrast-enhanced thorax computed tomography of patients victims of thoracic trauma admitted to the emergency unit of IJF, between November 1st, 2014 and January 31st, 2015. Results: Abnormal findings were observed in 91,2 % of the patients. Among them, the following findings were most frequently observed: fractures (48%, hemothorax (43%, atelectasis (37%, pneumothorax (26% and lung contusions (17% Rupture of the esophagus was seen in three patients. Conclusion: We recognize that the findings encountered in our study are of similar prevalence to the ones reported in the literature and that CT scan is essencial to quickly diagnose these findings.

  10. Phantom evaluation of a cardiac SPECT/VCT system that uses a common set of solid-state detectors for both emission and transmission scans.

    Science.gov (United States)

    Bai, Chuanyong; Conwell, Richard; Kindem, Joel; Babla, Hetal; Gurley, Mike; De Los Santos, Romer; Old, Rex; Weatherhead, Randy; Arram, Samia; Maddahi, Jamshid

    2010-06-01

    We developed a cardiac SPECT system (X-ACT) with low dose volume CT transmission-based attenuation correction (AC). Three solid-state detectors are configured to form a triple-head system for emission scans and reconfigured to form a 69-cm field-of-view detector arc for transmission scans. A near mono-energetic transmission line source is produced from the collimated fluorescence x-ray emitted from a lead target when the target is illuminated by a narrow polychromatic x-ray beam from an x-ray tube. Transmission scans can be completed in 1 min with insignificant patient dose (deep dose equivalent used phantom studies to evaluate (1) the accuracy of the reconstructed attenuation maps, (2) the effect of AC on image uniformity, and (3) the effect of AC on defect contrast (DC). The phantoms we used included an ACR phantom, an anthropomorphic phantom with a uniform cardiac insert, and an anthropomorphic phantom with two defects in the cardiac insert. The reconstructed attenuation coefficient of water at 140 keV was .150 +/- .003/cm in the uniform region of the ACR phantom, .151 +/- .003/cm and .151 +/- .002/cm in the liver and cardiac regions of the anthropomorphic phantom. The ACR phantom images with AC showed correction of the bowing effect due to attenuation in the images without AC (NC). The 17-segment scores of the images of the uniform cardiac insert were 78.3 +/- 6.5 before and 87.9 +/- 3.3 after AC (average +/- standard deviation). The inferior-to-anterior wall ratio and the septal-to-lateral wall ratio were .99 and 1.16 before and 1.02 and 1.00 after AC. The DC of the two defects was .528 and .156 before and .628 and .173 after AC. The X-ACT system generated accurate attenuation maps with 1-minute transmission scans. AC improved image quality and uniformity over NC.

  11. MR Venography of the Central Veins of the Thorax.

    Science.gov (United States)

    Cline, Brendan; Hurwitz, Lynne M; Kim, Charles Y

    2017-08-01

    While imaging of the central venous system has traditionally been performed with conventional venography, MR venography (MRV) has emerged as an important modality as techniques and validation studies have evolved over time. While magnetic resonance angiography has a very robust representation in the literature, the proportion representing MRV is relatively sparse. The purpose of this article is to review the indications, techniques, and dedicated studies validating MRV of the central veins of the thorax.

  12. Influence of thorax irradiation on lactic dehydrogenase isoenzyme activity

    International Nuclear Information System (INIS)

    Valle, C.; Munnich, A.; Pasquier, C.

    The right hemi-thorax of rats was irradiated with 1200 and 3000 rads ( 60 Co) and blood samples were taken sequentially. The five lactic dehydrogenase (LDH) isoenzymes which have proved to be useful as biochemical indicators of acute pulmonary injury in other experimental animals (dogs), were assayed, after irradiation, as a function of time and as a functon of dose. There was no significant change in LDH isoenzyme activities after lung irradiation in rats [fr

  13. ADAM: A breathing phantom for lung SBRT quality assurance.

    Science.gov (United States)

    Pallotta, Stefania; Calusi, Silvia; Foggi, Leonardo; Lisci, Riccardo; Masi, Laura; Marrazzo, Livia; Talamonti, Cinzia; Livi, Lorenzo; Simontacchi, Gabriele

    2017-07-20

    Radiotherapy treatment of moving lesions is a challenging task in which different strategies can be used to adequately treat the tumor while sparing the surrounding tissue. The complexity of these strategies requires accurate and appropriate quality assurance tests. For this purpose, ADAM (Anthropomorphic Dynamic breAthing Model), a new phantom which simulates realistic patient breathing, was developed aiming to test the image quality and dose delivery in lung cancer treatments. ADAM reproduces a male torso complete with a moving anterior chest wall and internal parts. The phantom's external body is printed with a 3D printer using acrylonitrile butadiene styrene. Internal lungs, ribs, spinal cord, and lung tumor (LT) are made of materials that simulate human tissues. Driven by an Arduino programmable board, the lungs can move along linear or elliptical paths while the anterior chest wall moves up and down. Phantom features and usability, reproducibility of LT position in the phantom chest, internal and external motion repeatability and tumor-to-surface motion correlation were investigated. Hounsfield Units of the employed materials demonstrates the phantom adequately simulates human tissues. Tests performed with the Synchrony system confirm ADAM's suitability for respiratory internal tracking. Reproducibility of the internal structure position is within 1mm as are internal and external motion repeatability. A strong positive correlation is found between the lung and chest wall positions (R 2 =0.999). ADAM demonstrates to be suitable to be employed with gating and tracking devices used in the treatment of moving lesions. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  14. Dose calculation on voxels phantoms using the GEANT4 code

    International Nuclear Information System (INIS)

    Martins, Maximiano C.; Santos, Denison S.; Queiroz Filho, Pedro P.; Begalli, Marcia

    2009-01-01

    This work implemented an anthropomorphic phantom of voxels on the structure of Monte Carlo GEANT4, for utilization by professionals from the radioprotection, external dosimetry and medical physics. This phantom allows the source displacement that can be isotropic punctual, plain beam, linear or radioactive gas, in order to obtain diverse irradiation geometries. In them, the radioactive sources exposure is simulated viewing the determination of effective dose or the dose in each organ of the human body. The Zubal head and body trunk phantom was used, and we can differentiate the organs and tissues by the chemical constitution in soft tissue, lung tissue, bone tissue, water and air. The calculation method was validated through the comparison with other well established method, the Visual Monte Carlo (VMC). Besides, a comparison was done with the international recommendation for the evaluation of dose by exposure to punctual sources, described in the document TECDOC - 1162- Generic Procedures for Assessment and Response During a Radiological Emergency, where analytical expressions for this calculation are given. Considerations are made on the validity limits of these expressions for various irradiation geometries, including linear sources, immersion into clouds and contaminated soils

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

    Science.gov (United States)

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

    2007-07-01

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

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

    International Nuclear Information System (INIS)

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

    2007-01-01

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

  17. Scatter correction method for x-ray CT using primary modulation: Phantom studies

    International Nuclear Information System (INIS)

    Gao Hewei; Fahrig, Rebecca; Bennett, N. Robert; Sun Mingshan; Star-Lack, Josh; Zhu Lei

    2010-01-01

    Purpose: Scatter correction is a major challenge in x-ray imaging using large area detectors. Recently, the authors proposed a promising scatter correction method for x-ray computed tomography (CT) using primary modulation. Proof of concept was previously illustrated by Monte Carlo simulations and physical experiments on a small phantom with a simple geometry. In this work, the authors provide a quantitative evaluation of the primary modulation technique and demonstrate its performance in applications where scatter correction is more challenging. Methods: The authors first analyze the potential errors of the estimated scatter in the primary modulation method. On two tabletop CT systems, the method is investigated using three phantoms: A Catphan(c)600 phantom, an anthropomorphic chest phantom, and the Catphan(c)600 phantom with two annuli. Two different primary modulators are also designed to show the impact of the modulator parameters on the scatter correction efficiency. The first is an aluminum modulator with a weak modulation and a low modulation frequency, and the second is a copper modulator with a strong modulation and a high modulation frequency. Results: On the Catphan(c)600 phantom in the first study, the method reduces the error of the CT number in the selected regions of interest (ROIs) from 371.4 to 21.9 Hounsfield units (HU); the contrast to noise ratio also increases from 10.9 to 19.2. On the anthropomorphic chest phantom in the second study, which represents a more difficult case due to the high scatter signals and object heterogeneity, the method reduces the error of the CT number from 327 to 19 HU in the selected ROIs and from 31.4% to 5.7% on the overall average. The third study is to investigate the impact of object size on the efficiency of our method. The scatter-to-primary ratio estimation error on the Catphan(c)600 phantom without any annulus (20 cm in diameter) is at the level of 0.04, it rises to 0.07 and 0.1 on the phantom with an

  18. 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…

  19. The Phantom Menace

    DEFF Research Database (Denmark)

    Vium, Christian

    2013-01-01

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

  20. Are anthropomorphic persuasive appeals effective? The role of the recipient's motivations.

    Science.gov (United States)

    Tam, Kim-Pong

    2015-03-01

    Anthropomorphic persuasive appeals are prevalent. However, their effectiveness has not been well studied. The present research addresses this issue with two experiments in the context of environmental persuasion. It shows that anthropomorphic messages, relative to non-anthropomorphic ones, appear to motivate more conservation behaviour and elicit more favourable message responses only among recipients who have a strong need for effectance or social connection. Among recipients whose such need is weak, anthropomorphic appeals seem to backfire. These findings extend the research on motivation and persuasion and add evidence to the motivational bases of anthropomorphism. In addition, joining some recent studies, the present research highlights the implications of anthropomorphism of nature for environmental conservation efforts, and offers some practical suggestions for environmental persuasion. © 2014 The British Psychological Society.

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

    Science.gov (United States)

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

    2017-01-01

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

  2. A 4D digital phantom for patient-specific simulation of brain CT perfusion protocols.

    Science.gov (United States)

    van den Boom, Rieneke; Manniesing, Rashindra; Oei, Marcel T H; van der Woude, Willem-Jan; Smit, Ewoud J; Laue, Hendrik O A; van Ginneken, Bram; Prokop, Mathias

    2014-07-01

    Optimizing CT brain perfusion protocols is a challenge because of the complex interaction between image acquisition, calculation of perfusion data, and patient hemodynamics. Several digital phantoms have been developed to avoid unnecessary patient exposure or suboptimum choice of parameters. The authors expand this idea by using realistic noise patterns and measured tissue attenuation curves representing patient-specific hemodynamics. The purpose of this work is to validate that this approach can realistically simulate mean perfusion values and noise on perfusion data for individual patients. The proposed 4D digital phantom consists of three major components: (1) a definition of the spatial structure of various brain tissues within the phantom, (2) measured tissue attenuation curves, and (3) measured noise patterns. Tissue attenuation curves were measured in patient data using regions of interest in gray matter and white matter. By assigning the tissue attenuation curves to the corresponding tissue curves within the phantom, patient-specific CTP acquisitions were retrospectively simulated. Noise patterns were acquired by repeatedly scanning an anthropomorphic skull phantom at various exposure settings. The authors selected 20 consecutive patients that were scanned for suspected ischemic stroke and constructed patient-specific 4D digital phantoms using the individual patients' hemodynamics. The perfusion maps of the patient data were compared with the digital phantom data. Agreement between phantom- and patient-derived data was determined for mean perfusion values and for standard deviation in de perfusion data using intraclass correlation coefficients (ICCs) and a linear fit. ICCs ranged between 0.92 and 0.99 for mean perfusion values. ICCs for the standard deviation in perfusion maps were between 0.86 and 0.93. Linear fitting yielded slope values between 0.90 and 1.06. A patient-specific 4D digital phantom allows for realistic simulation of mean values and

  3. Transfer Relation between the Compression Test Rig and the Anthropomorphic Test Device (ATD) Lower Leg

    Science.gov (United States)

    2015-08-01

    Transfer Relation between the Compression Test Rig and the Anthropomorphic Test Device (ATD) Lower Leg by Masayuki Sakamoto ARL-SR-0330...1138 ARL-SR-0330 August 2015 Transfer Relation between the Compression Test Rig and the Anthropomorphic Test Device (ATD) Lower Leg ...Relation between the Compression Test Rig and the Anthropomorphic Test Device (ATD) Lower Leg 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM

  4. Influence of the Pulse Duration in the Anthropomorphic Test Device (ATD) Lower-Leg Loading Mechanics

    Science.gov (United States)

    2015-08-01

    Influence of the Pulse Duration in the Anthropomorphic Test Device (ATD) Lower- Leg Loading Mechanics by Masayuki Sakamoto ARL-SR-0331...ARL-SR-0331 August 2015 Influence of the Pulse Duration in the Anthropomorphic Test Device (ATD) Lower- Leg Loading Mechanics Masayuki...Pulse Duration in the Anthropomorphic Test Device (ATD) Lower- Leg Loading Mechanics 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT

  5. How gestures affect students: A comparative experiment using class presentations conducted by an anthropomorphic agent

    Science.gov (United States)

    Shirakawa, Tomohiro; Sato, Hiroshi; Imao, Tomoya

    2017-07-01

    Recently, a variety of user interfaces have been developed based on human-robot and human-agent interaction, and anthropomorphic agents are used as one type of interface. However, the use of anthropomorphic agents is applied mainly to the medical and cognitive sciences, and there are few studies of their application to other fields. Therefore, we used an anthropomorphic agent of MMD in a virtual lecture to analyze the effect of gestures on students and search for ways to apply anthropomorphic agents to the field of educational technology.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-12-15

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

  7. CT doses in cylindrical phantoms

    International Nuclear Information System (INIS)

    Atherton, J.V.; Huda, W.

    1995-01-01

    A single CT scan of thickness T in a cylindrical phantom produces a three-dimensional dose distribution, which depends primarily on the photon energy spectrum, the x-ray beam shaping filter and the size and composition of the irradiated phantom. Monte Carlo simulations employing monoenergetic photons were employed to investigate the effect of each of these factors on phantom dose distributions. The fractional energies scattered, imparted and transmitted through the CT phantom were calculated. A dose index (D(r)), which is a function of phantom radius r, was computed. Phantom materials investigated included lung, fat, water, soft tissue, acrylic and bone with calculations performed for head (160 mm diameter) and body (320 mm diameter) phantoms. All dose and energy imparted data generated for CT phantoms were normalized using an 'in air' dose (D air ), which is defined as the axial dose (in acrylic) at the isocentre in the absence of any phantom. Results obtained show how CT parameters impact on doses in cylindrical phantoms. These dosimetry data are likely to be useful to estimate energy imparted to phantoms (and patients) undergoing CT examinations. (author)

  8. 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...... was 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...

  9. Regular phantom black holes.

    Science.gov (United States)

    Bronnikov, K A; Fabris, J C

    2006-06-30

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

  10. Design and Fabrication of Kidney Phantoms for Internal Radiation Dosimetry Using 3D Printing Technology.

    Science.gov (United States)

    Tran-Gia, Johannes; Schlögl, Susanne; Lassmann, Michael

    2016-12-01

    Currently, the validation of multimodal quantitative imaging and absorbed dose measurements is impeded by the lack of suitable, commercially available anthropomorphic phantoms of variable sizes and shapes. To demonstrate the potential of 3-dimensional (3D) printing techniques for quantitative SPECT/CT imaging, a set of kidney dosimetry phantoms and their spherical counterparts was designed and manufactured with a fused-deposition-modeling 3D printer. Nuclide-dependent SPECT/CT calibration factors were determined to assess the accuracy of quantitative imaging for internal renal dosimetry. A set of 4 single-compartment kidney phantoms with filling volumes between 8 and 123 mL was designed on the basis of the outer kidney dimensions provided by MIRD pamphlet 19. After the phantoms had been printed, SPECT/CT acquisitions of 3 radionuclides ( 99m Tc, 177 Lu, and 131 I) were obtained and calibration constants determined for each radionuclide-volume combination. A set of additionally manufactured spheres matching the kidney volumes was also examined to assess the influence of phantom shape and size on the calibration constants. A set of refillable, waterproof, and chemically stable kidneys and spheres was successfully manufactured. Average calibration factors for 99m Tc, 177 Lu, and 131 I were obtained in a large source measured in air. For the largest phantom (122.9 mL), the volumes of interest had to be enlarged by 1.2 mm for 99m Tc, 2.5 mm for 177 Lu, and 4.9 mm for 131 I in all directions to obtain calibration factors comparable to the reference. Although partial-volume effects were observed for decreasing phantom volumes (percentage difference of up to 9.8% for the smallest volume [8.6 mL]), the difference between corresponding sphere-kidney pairs was small (3D printing is a promising prototyping technique for geometry-specific calibration of SPECT/CT systems. Although the underlying radionuclide and the related collimator have a major influence on the calibration

  11. Comparison study of reconstruction algorithms for prototype digital breast tomosynthesis using various breast phantoms.

    Science.gov (United States)

    Kim, Ye-seul; Park, Hye-suk; Lee, Haeng-Hwa; Choi, Young-Wook; Choi, Jae-Gu; Kim, Hak Hee; Kim, Hee-Joung

    2016-02-01

    Digital breast tomosynthesis (DBT) is a recently developed system for three-dimensional imaging that offers the potential to reduce the false positives of mammography by preventing tissue overlap. Many qualitative evaluations of digital breast tomosynthesis were previously performed by using a phantom with an unrealistic model and with heterogeneous background and noise, which is not representative of real breasts. The purpose of the present work was to compare reconstruction algorithms for DBT by using various breast phantoms; validation was also performed by using patient images. DBT was performed by using a prototype unit that was optimized for very low exposures and rapid readout. Three algorithms were compared: a back-projection (BP) algorithm, a filtered BP (FBP) algorithm, and an iterative expectation maximization (EM) algorithm. To compare the algorithms, three types of breast phantoms (homogeneous background phantom, heterogeneous background phantom, and anthropomorphic breast phantom) were evaluated, and clinical images were also reconstructed by using the different reconstruction algorithms. The in-plane image quality was evaluated based on the line profile and the contrast-to-noise ratio (CNR), and out-of-plane artifacts were evaluated by means of the artifact spread function (ASF). Parenchymal texture features of contrast and homogeneity were computed based on reconstructed images of an anthropomorphic breast phantom. The clinical images were studied to validate the effect of reconstruction algorithms. The results showed that the CNRs of masses reconstructed by using the EM algorithm were slightly higher than those obtained by using the BP algorithm, whereas the FBP algorithm yielded much lower CNR due to its high fluctuations of background noise. The FBP algorithm provides the best conspicuity for larger calcifications by enhancing their contrast and sharpness more than the other algorithms; however, in the case of small-size and low

  12. Human-Like Movement of an Anthropomorphic Robot: Problem Revisited

    Science.gov (United States)

    e Silva, E. Costa; Costa, M. F.; Bicho, E.; Erlhagen, W.

    2011-09-01

    Human-like movement is fundamental for natural human-robot interaction and collaboration. We have developed in a model for generating arm and hand movements an anthropomorphic robot. This model was inspired by the Posture-Based Motion-Planning Model of human reaching and grasping movements. In this paper we present some changes to the model we have proposed in [4] and test and compare different nonlinear constrained optimization techniques for solving the large-scale nonlinear constrained optimization problem that rises from the discretization of our time-continuous model. Furthermore, we test different time discretization steps.

  13. Radiological diagnostics of abdomen and thorax. Image interpretation considering anatomical landmarks and clinical symptoms

    International Nuclear Information System (INIS)

    Krombach, Gabriele A.; Mahnken, Andreas H.

    2015-01-01

    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.

  14. Solid water phantom

    International Nuclear Information System (INIS)

    Arguiropulo, M.Y.; Ghilardi Neto, T.; Pela, C.A.; Ghilardi, A.J.P.

    1992-01-01

    A phantom were developed for simulating water, based in plastics. The material was evaluated for different energies, and the measures of relative transmission showed that the transmission and the water were inside of 0,6% for gamma rays. The results of this new material were presented, showing that it could be used in photon beam calibration with energies on radiotherapy range. (C.G.C.)

  15. Diagnosis of anemia on CT scans of the thorax

    International Nuclear Information System (INIS)

    Corcoran, H.L.; Cook, D.E.; Proto, A.V.

    1986-01-01

    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

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

    International Nuclear Information System (INIS)

    Parente Filho, Livio William Sales; Marchiori, Edson; Daltro, Pedro; Santos, Eloa Nunes

    1998-01-01

    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)

  17. Radiographic Examination of the Lungs and Thorax Cavity in Equine

    Directory of Open Access Journals (Sweden)

    Radu LĂCĂTUȘ

    2017-11-01

    The mobile arms of the device give the possibility of adjusting the distance between the X-Ray tube and the detector, because of these one or two exposures were enough to examine the entire thoracic cavity. The interstitial patter is more evident in horses that in small mammals given the gross anatomy of the lungs. The radiological parameters were adjusted according to thoracic cavity depth. Radiographic examination is a necessary tool that completes the clinical examination. The up-to-date detectors used in veterinary radiology give the clinician the possibility of a detailed examination of the lung parenchyma and the thorax structures.

  18. Common pitfalls in radiographic interpretation of the Thorax

    International Nuclear Information System (INIS)

    Godshalk, C.P.

    1994-01-01

    Errors in radiographic interpretation of the thorax are common. Many mistakes result from interpreting normal anatomic variants as abnormalstructures, such as misdiagnosing dorsal and rightward deviation of the cranial thoracic trachea on lateral radiographs of normal dogs. Some of the more common errors specifically relate to misinterpretation of radiographs made on obese patients. The age of the patient also plays a role in misdiagnosis. Aging cats seem to have a horizontally positioned heart on lateral radiographs, and older dogs, primarily collies,often have pulmonary osteomas that are misdiagnosed as metastatic neoplastic disease or healed pulmonary fungal infections

  19. Technical Note: Radiological properties of tissue surrogates used in a multimodality deformable pelvic phantom for MR-guided radiotherapy

    International Nuclear Information System (INIS)

    Niebuhr, Nina I.; Johnen, Wibke; Güldaglar, Timur; Runz, Armin; Echner, Gernot; Mann, Philipp; Möhler, Christian; Pfaffenberger, Asja; Greilich, Steffen; Jäkel, Oliver

    2016-01-01

    Purpose: Phantom surrogates were developed to allow multimodal [computed tomography (CT), magnetic resonance imaging (MRI), and teletherapy] and anthropomorphic tissue simulation as well as materials and methods to construct deformable organ shapes and anthropomorphic bone models. Methods: Agarose gels of variable concentrations and loadings were investigated to simulate various soft tissue types. Oils, fats, and Vaseline were investigated as surrogates for adipose tissue and bone marrow. Anthropomorphic shapes of bone and organs were realized using 3D-printing techniques based on segmentations of patient CT-scans. All materials were characterized in dual energy CT and MRI to adapt CT numbers, electron density, effective atomic number, as well as T1- and T2-relaxation times to patient and literature values. Results: Soft tissue simulation could be achieved with agarose gels in combination with a gadolinium-based contrast agent and NaF to simulate muscle, prostate, and tumor tissues. Vegetable oils were shown to be a good representation for adipose tissue in all modalities. Inner bone was realized using a mixture of Vaseline and K 2 HPO 4 , resulting in both a fatty bone marrow signal in MRI and inhomogeneous areas of low and high attenuation in CT. The high attenuation of outer bone was additionally adapted by applying gypsum bandages to the 3D-printed hollow bone case with values up to 1200 HU. Deformable hollow organs were manufactured using silicone. Signal loss in the MR images based on the conductivity of the gels needs to be further investigated. Conclusions: The presented surrogates and techniques allow the customized construction of multimodality, anthropomorphic, and deformable phantoms as exemplarily shown for a pelvic phantom, which is intended to study adaptive treatment scenarios in MR-guided radiation therapy

  20. Technical Note: Radiological properties of tissue surrogates used in a multimodality deformable pelvic phantom for MR-guided radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Niebuhr, Nina I., E-mail: n.niebuhr@dkfz.de; Johnen, Wibke; Güldaglar, Timur; Runz, Armin; Echner, Gernot; Mann, Philipp; Möhler, Christian; Pfaffenberger, Asja; Greilich, Steffen [Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg 69120, Germany and Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology, Im Neuenheimer Feld 280, Heidelberg 69120 (Germany); Jäkel, Oliver [Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg 69120 (Germany); Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology, Im Neuenheimer Feld 280, Heidelberg 69120 (Germany); Department of Medical Physics, Heidelberg Ion-Beam Therapy Center (HIT), Im Neuenheimer Feld 450, Heidelberg 69120 (Germany)

    2016-02-15

    Purpose: Phantom surrogates were developed to allow multimodal [computed tomography (CT), magnetic resonance imaging (MRI), and teletherapy] and anthropomorphic tissue simulation as well as materials and methods to construct deformable organ shapes and anthropomorphic bone models. Methods: Agarose gels of variable concentrations and loadings were investigated to simulate various soft tissue types. Oils, fats, and Vaseline were investigated as surrogates for adipose tissue and bone marrow. Anthropomorphic shapes of bone and organs were realized using 3D-printing techniques based on segmentations of patient CT-scans. All materials were characterized in dual energy CT and MRI to adapt CT numbers, electron density, effective atomic number, as well as T1- and T2-relaxation times to patient and literature values. Results: Soft tissue simulation could be achieved with agarose gels in combination with a gadolinium-based contrast agent and NaF to simulate muscle, prostate, and tumor tissues. Vegetable oils were shown to be a good representation for adipose tissue in all modalities. Inner bone was realized using a mixture of Vaseline and K{sub 2}HPO{sub 4}, resulting in both a fatty bone marrow signal in MRI and inhomogeneous areas of low and high attenuation in CT. The high attenuation of outer bone was additionally adapted by applying gypsum bandages to the 3D-printed hollow bone case with values up to 1200 HU. Deformable hollow organs were manufactured using silicone. Signal loss in the MR images based on the conductivity of the gels needs to be further investigated. Conclusions: The presented surrogates and techniques allow the customized construction of multimodality, anthropomorphic, and deformable phantoms as exemplarily shown for a pelvic phantom, which is intended to study adaptive treatment scenarios in MR-guided radiation therapy.

  1. Analysis of Inverse Kinamtics of an Anthropomorphic Robotic hand

    Directory of Open Access Journals (Sweden)

    Pramod Kumar Parida

    2013-03-01

    Full Text Available In this paper, a new method for solving the inverse kinematics of the fingers of an anthropomorphic hand is proposed. Solution of inverse kinematic equations is a complex problem, the complexity comes from the nonlinearity of joint space and Cartesian space mapping and having multiple solutions.This is a typical problem in robotics that needs to be solved to control the fingers of an anthropomorphic robotic hand to perform tasks it is designated to do. With more complex structures operating in a 3-dimensional space deducing a mathematical soluation for the inverse kinematics may prove challenging. In this paper, using the ability of ANFIS (Adaptive Neuro-Fuzzy Inference System to learn from training data, it is possible to create ANFIS network, an implementation of a representative fuzzy inference system using ANFIS structure, with limited mathematical representation of the system. The main advantages of this method with respect to the other methods are implementation is easy, very fast and shorter computation time and better response with acceptable error.

  2. Almost human: Anthropomorphism increases trust resilience in cognitive agents.

    Science.gov (United States)

    de Visser, Ewart J; Monfort, Samuel S; McKendrick, Ryan; Smith, Melissa A B; McKnight, Patrick E; Krueger, Frank; Parasuraman, Raja

    2016-09-01

    We interact daily with computers that appear and behave like humans. Some researchers propose that people apply the same social norms to computers as they do to humans, suggesting that social psychological knowledge can be applied to our interactions with computers. In contrast, theories of human–automation interaction postulate that humans respond to machines in unique and specific ways. We believe that anthropomorphism—the degree to which an agent exhibits human characteristics—is the critical variable that may resolve this apparent contradiction across the formation, violation, and repair stages of trust. Three experiments were designed to examine these opposing viewpoints by varying the appearance and behavior of automated agents. Participants received advice that deteriorated gradually in reliability from a computer, avatar, or human agent. Our results showed (a) that anthropomorphic agents were associated with greater trust resilience , a higher resistance to breakdowns in trust; (b) that these effects were magnified by greater uncertainty; and c) that incorporating human-like trust repair behavior largely erased differences between the agents. Automation anthropomorphism is therefore a critical variable that should be carefully incorporated into any general theory of human–agent trust as well as novel automation design. PsycINFO Database Record (c) 2016 APA, all rights reserved

  3. 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.

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

    International Nuclear Information System (INIS)

    Lima Filho, Jose de Melo; Vieira, Jose Wilson; Lima, Vanildo Junior de Melo; Lima, Fernando Roberto de Andrade

    2009-01-01

    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)

  5. Evaluation of anemia on unenhanced CT of the thorax

    International Nuclear Information System (INIS)

    Zhang Yuzhong; Zhang Xuelin; Zhong Qun; Zhang Fan; Zhang Wensheng

    2006-01-01

    Objective: To explore the correlation between CT density of blood in Cardiac Chambers and hemoglobin concentration in blood, and to evaluate the veracity of diagnosis of aneamia on unenhanced computed tomography of the thorax. Methods: Thorax (heart) helical CT was performed in 92 patients. In each case, the CT values of the blood pool in left ventricle and ventricular septum were tested, and the ratio of blood pool/ventricular septum were calculated. The hemoglobin concentration in blood was tested. The correlation among these indexes were analysed. Results: In these factors, CT density of blood was strongly and positively correlated with hemoglobin concentration in blood (r=0.571, P=0.000), and the CT density ratio was also strongly and positively correlated with hemoglobin concentration in blood (r=0.650, P=0.000). It dramatically implies that the patient may be suffering from aneamia when the ratio is Ness than 90% (male) or 87% (female). Conclusion: Blood pool/ventricular septum CT density ratio may be as a reliable indicator for judging and grading aneamia with CT. (authors)

  6. Anthropomorphically Speaking: On Communication between Teachers and Children in Early Childhood Biology Education

    Science.gov (United States)

    Thulin, Susanne; Pramling, Niklas

    2009-01-01

    In this study a particular kind of figurative language, so-called anthropomorphic speech, is analysed in the context of science activities in a preschool setting. Anthropomorphism means speaking about something non-human in human terms. Can any systematic pattern be seen with regard to when such speech is used? Do children and/or teachers…

  7. Phantom breast syndrome

    Directory of Open Access Journals (Sweden)

    Ramesh

    2009-01-01

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

  8. Do storybooks with anthropomorphized animal characters promote prosocial behaviors in young children?

    Science.gov (United States)

    Larsen, Nicole E; Lee, Kang; Ganea, Patricia A

    2018-05-01

    For millennia, adults have told children stories not only to entertain but also to impart important moral lessons to promote prosocial behaviors. Many such stories contain anthropomorphized animals because it is believed that children learn from anthropomorphic stories as effectively, if not better than, from stories with human characters, and thus are more inclined to act according to the moral lessons of the stories. Here we experimentally tested this belief by reading preschoolers a sharing story with either human characters or anthropomorphized animal characters. Reading the human story significantly increased preschoolers' altruistic giving but reading the anthropomorphic story or a control story decreased it. Thus, contrary to the common belief, realistic stories, not anthropomorphic ones, are better for promoting young children's prosocial behavior. © 2017 John Wiley & Sons Ltd.

  9. A multivendor phantom study comparing the image quality produced from three state-of-the-art SPECT-CT systems.

    Science.gov (United States)

    Hughes, Tyler; Celler, Anna

    2012-06-01

    Ongoing advancements in single photon emission computed tomography with on-board X-ray computed tomography (SPECT-CT) hardware and software raise important questions regarding the relative performances of various cameras and their respective image-processing software. This phantom-based study compares images produced from three state-of-the-art cameras using four image quality measurements. A thorax phantom modeling the spine, lungs, a healthy heart, and three tumors (cylindrical bottles) was scanned using the following SPECT-CT systems: Philips' Precedence (PP), GE's Infinia-Hawkeye (GH), and Siemens' Symbia-T6 (SS). For each scan, Tc-99m solutions were injected into the heart, three bottles, and thorax to yield activity concentration ratios of roughly 6:1 for both heart:thorax and tumor:thorax. The data were reconstructed using the most advanced software available on the cameras, namely, Evolution for Bone and Evolution for Cardiac (EVB and EVC, respectively), Astonish (AST), and Flash3D (FLA) for GH, PP, and SS, respectively. In addition, all sets of data were reconstructed using our in-house software. The mean values of activity error, uniformity, signal-to-noise ratio, and contrast error were used as figures of merit (FOM). No significant differences were observed for all FOM between all in-house reconstructions using PP, GH, and SS acquisition data. The mean activity error for the AST reconstruction (-24.0±1.6%) was significantly closer to the truth relative to EVB (-38.0±1.6%), EVC (-34.5±2.3%), and FLA (-33.8±1.6%). No significant differences were found between EVC and FLA for all FOM. In this phantom-based study, Philips' AST provided the most quantitatively accurate and highest contrast images, whereas Siemens' FLA and GE's EVC provided relatively higher signal-to-noise ratios and more uniform images.

  10. The Phantom of Liberty

    DEFF Research Database (Denmark)

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

  11. 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.

  12. Evaluation of the image quality of chest CT scans: a phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Martins N, P. I.; Prata M, A., E-mail: priscillainglid@gmail.com [Centro Federal de Educacao Tecnologica de Minas Gerais, Centro de Engenharia Biomedica, Av. Amazonas 5253, 30421-169 Nova Suica, Belo Horizonte, Minas Gerais (Brazil)

    2016-10-15

    Computed tomography (CT) is considered one of the most important methods of medical imaging employed nowadays, due to its non-invasiveness and the high quality of the images it is able to generate. However, the diagnostic radiation dose received by an individual over the year often exceeds the dose received on account of background radiation. Therefore, it is important to know and to control the dose distribution in the patient by varying the image acquisition parameters. The aim of this study is to evaluate the variation of the image quality of chest CT scans performed by two phantoms. In this paper, a cylindrical Polymethyl Methacrylate (PMMA) chest phantom was used and a second PMMA phantom has been developed with the same volume but an oblong shape, based on the actual dimensions of a male human thorax, in the axillary region. Ten-centimeter scans of the central area of each phantom were performed by a 16-channel Toshiba CT scanner, model Alexion. The scanning protocol employed was the radiology service protocol for chest scans. The noise survey was conducted within the image of the center slice, in five regions: one central and four peripheral areas close to the edge of the object (anterior, posterior, left and right). The recorded values showed that the oblong phantom, with a shape that is more similar to the actual human chest, has a considerably smaller noise, especially in the anterior, posterior and central regions. (Author)

  13. 3D geometric morphometrics of thorax variation and allometry in Hominoidea.

    Science.gov (United States)

    Bastir, Markus; García-Martínez, Daniel; Williams, Scott A; Recheis, Wolfgang; Torres-Sánchez, Isabel; García Río, Francisco; Oishi, Motoharu; Ogihara, Naomichi

    2017-12-01

    Ever since the seminal papers of Keith and Schultz, hominoid primate ribcages have been described as either "funnel-" or "barrel-shaped." Following this dichotomic typology, it is currently held that Homo sapiens and hylobatids (gibbons and siamangs) share a barrel-shaped ribcage and that they are more similar to each other than to the funnel-shaped thoraces of great apes (Gorilla, Pan, and Pongo). Other researchers hypothesized that thoracic width and the invagination of the thoracic spine into the thorax are related to allometry. However, analyses that take into account the complex three-dimensional (3D) shape of the ribcage are lacking. Here, we address hypotheses about thorax shape and evolution using 3D morphometrics of thoraces in anatomical connection obtained by computed tomography scans of 23 hominoid cadavers and 10 humans and examining thorax compartments composed of seven ribs (1-7 thorax) and of 11 ribs (1-11 thorax). In the 1-7 thorax analyses, the human thorax is uniquely flat because of torsion of the upper and central ribs, differing from all non-human hominoids including hylobatids. In the 1-11 thorax analyses, humans are markedly different from African great apes, with hylobatids and orangutans intermediate. In full shape space analyses, affinities between orangutans and humans on the one hand and between hylobatids and African great apes on the other are evident. Therefore, we reject the hypothesis that humans and hylobatids bear any special affinities in overall 3D thorax shape to each other. We find that larger thoraces are wider and flatter, with a more invaginated spine, supporting the allometric hypothesis. Hominoid thorax variation shows complex interactions between allometry, rib curves, torsion, and declination, and the morphology of the costo-vertebral joint and the thoracic vertebral column. When considering functional specializations alongside phylogenetic relationships, an overly simplistic dichotomy between funnel-shaped and barrel

  14. Oblique and lateral impact response of the PMHS thorax.

    Science.gov (United States)

    Shaw, Joshua M; Herriott, Rodney G; McFadden, Joseph D; Donnelly, Bruce R; Bolte, John H

    2006-11-01

    This study characterizes the PMHS thoracic response to blunt impact in oblique and lateral directions. A significant amount of data has been collected from lateral impacts conducted on human cadavers. Substantially less data has been collected from impacts that are anterior of lateral in an oblique direction. In the past, data collected from the handful of oblique impact studies were considered to be similar enough to the data from purely lateral impacts such that the oblique data were combined with data from lateral impacts. Defining the biomechanical response of the PMHS thorax to oblique impact is of great importance in side impact vehicle crashes where the loading is often anterior-oblique in direction. Data in this study was obtained from a chestband placed on the thorax at the level of impact to measure thoracic deflection. Two low energy impacts were conducted on each of seven subjects at 2.5 m/s, with one lateral impact and one oblique impact to opposite sides of each PMHS. Data was normalized using the Mertz-Viano method for a two mass system to allow for inter-subject comparisons. Force versus deflection response corridors were generated for the two impact types using an objective mathematical approach and compared to one another. Results were also compared to existing data for oblique and lateral thoracic impacts. The oblique thoracic response in low speed pendulum impacts was found to be different than the lateral thoracic response, in terms of force and deflection. Specifically, the lateral force was greater than the oblique force, and oblique deflection greater than lateral deflection for equal energy impacts.

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

    International Nuclear Information System (INIS)

    Kamel, Ehab M.; Rizzo, Elena; Duran, Rafael; Goncalves-Matoso, Vasco; Schnyder, Pierre; Duchosal, Michel A.; Qanadli, Salah D.

    2008-01-01

    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.)

  16. 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)

    Ximenes, Edmir; Guimaraes, Maria Ines C. C.

    2008-01-01

    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

  17. Mistaking minds and machines: How speech affects dehumanization and anthropomorphism.

    Science.gov (United States)

    Schroeder, Juliana; Epley, Nicholas

    2016-11-01

    Treating a human mind like a machine is an essential component of dehumanization, whereas attributing a humanlike mind to a machine is an essential component of anthropomorphism. Here we tested how a cue closely connected to a person's actual mental experience-a humanlike voice-affects the likelihood of mistaking a person for a machine, or a machine for a person. We predicted that paralinguistic cues in speech are particularly likely to convey the presence of a humanlike mind, such that removing voice from communication (leaving only text) would increase the likelihood of mistaking the text's creator for a machine. Conversely, adding voice to a computer-generated script (resulting in speech) would increase the likelihood of mistaking the text's creator for a human. Four experiments confirmed these hypotheses, demonstrating that people are more likely to infer a human (vs. computer) creator when they hear a voice expressing thoughts than when they read the same thoughts in text. Adding human visual cues to text (i.e., seeing a person perform a script in a subtitled video clip), did not increase the likelihood of inferring a human creator compared with only reading text, suggesting that defining features of personhood may be conveyed more clearly in speech (Experiments 1 and 2). Removing the naturalistic paralinguistic cues that convey humanlike capacity for thinking and feeling, such as varied pace and intonation, eliminates the humanizing effect of speech (Experiment 4). We discuss implications for dehumanizing others through text-based media, and for anthropomorphizing machines through speech-based media. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

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

    International Nuclear Information System (INIS)

    Fatemi-Ardekani, A; Wronski, M; Kim, A; Stanisz, G; Sarfehnia, A; Keller, B

    2015-01-01

    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

  19. Construction of Korean female voxel phantom and its application to dosimetry

    International Nuclear Information System (INIS)

    Lee, Choon Ik

    2001-08-01

    A Korean female voxel phantom was constructed to overcome the limitations of anatomical description of the existing MRD-type mathematical anthropomorphic phantom and the example dose calculations were carried out for the radiation protection by using it. This whole body voxel phantom was based on the MRIs of the Korean adult female who falls into the reference Korean female group. The cross sectional human pictures from VHP of NLM was adopted for the modification and compensation of the missing MRIs of Korean adult female that include legs below upper thighs. From the gastrointestinal and respiratory organ which make obscure organ edges because of their continuing motion, the general anatomical knowledge were applied for the segmentation process. The Korean female whole body voxel phantom named in HYWOMAN is composed of 1,392,400 voxels that have width x length x height of 4mm x 4mm x 8mm for each with the total of 20 organs identified. With MDNP4B code the tissue equivalent doses were calculated for the four different energies of 0.4, 0.8, 2 and 8 MeV broad parallel gamma beam in AP, PA, LLAT and RLAT directions. The tissue equivalent doses were compared with those of ORNL adult female phantom under the same irradiation conditions. Despite of the small organ differences there could be found the considerable differences in tissue equivalent doses for some organs including thyroid, esophagus, kidneys and spleen. The cause of these discrepancies were proved to be the position of the organs in the phantom and the consequent shielding effects. With the methodology of this study, Korean reference male and female age-grouped voxel phantoms can be constructed and consequently the dosimetry system for typical Korean people is to be established

  20. What Is the Best Way to Contour Lung Tumors on PET Scans? Multiobserver Validation of a Gradient-Based Method Using a NSCLC Digital PET Phantom

    International Nuclear Information System (INIS)

    Werner-Wasik, Maria; Nelson, Arden D.; Choi, Walter; Arai, Yoshio; Faulhaber, Peter F.; Kang, Patrick; Almeida, Fabio D.; Xiao, Ying; Ohri, Nitin; Brockway, Kristin D.; Piper, Jonathan W.; Nelson, Aaron S.

    2012-01-01

    Purpose: To evaluate the accuracy and consistency of a gradient-based positron emission tomography (PET) segmentation method, GRADIENT, compared with manual (MANUAL) and constant threshold (THRESHOLD) methods. Methods and Materials: Contouring accuracy was evaluated with sphere phantoms and clinically realistic Monte Carlo PET phantoms of the thorax. The sphere phantoms were 10–37 mm in diameter and were acquired at five institutions emulating clinical conditions. One institution also acquired a sphere phantom with multiple source-to-background ratios of 2:1, 5:1, 10:1, 20:1, and 70:1. One observer segmented (contoured) each sphere with GRADIENT and THRESHOLD from 25% to 50% at 5% increments. Subsequently, seven physicians segmented 31 lesions (7–264 mL) from 25 digital thorax phantoms using GRADIENT, THRESHOLD, and MANUAL. Results: For spheres 20 mm (p < 0.065) and <20 mm (p < 0.015). For digital thorax phantoms, GRADIENT was the most accurate (p < 0.01), with a mean absolute % error in volume of 10.99% (11.9% SD), followed by 25% THRESHOLD at 17.5% (29.4% SD), and MANUAL at 19.5% (17.2% SD). GRADIENT had the least systematic bias, with a mean % error in volume of –0.05% (16.2% SD) compared with 25% THRESHOLD at –2.1% (34.2% SD) and MANUAL at –16.3% (20.2% SD; p value <0.01). Interobserver variability was reduced using GRADIENT compared with both 25% THRESHOLD and MANUAL (p value <0.01, Levene’s test). Conclusion: GRADIENT was the most accurate and consistent technique for target volume contouring. GRADIENT was also the most robust for varying imaging conditions. GRADIENT has the potential to play an important role for tumor delineation in radiation therapy planning and response assessment.

  1. Realistic phantoms to characterize dosimetry in pediatric CT

    Energy Technology Data Exchange (ETDEWEB)

    Carver, Diana E.; Kost, Susan D.; Fraser, Nicholas D.; Pickens, David R.; Price, Ronald R.; Stabin, Michael G. [Vanderbilt University Medical Center, Department of Radiology and Radiological Sciences, Nashville, TN (United States); Segars, W.P. [Duke University, Carl E. Ravin Advanced Imaging Laboratories, Durham, NC (United States)

    2017-05-15

    The estimation of organ doses and effective doses for children receiving CT examinations is of high interest. Newer, more realistic anthropomorphic body models can provide information on individual organ doses and improved estimates of effective dose. Previously developed body models representing 50th-percentile individuals at reference ages (newborn, 1, 5, 10 and 15 years) were modified to represent 10th, 25th, 75th and 90th height percentiles for both genders and an expanded range of ages (3, 8 and 13 years). We calculated doses for 80 pediatric reference phantoms from simulated chest-abdomen-pelvis exams on a model of a Philips Brilliance 64 CT scanner. Individual organ and effective doses were normalized to dose-length product (DLP) and fit as a function of body diameter. We calculated organ and effective doses for 80 reference phantoms and plotted them against body diameter. The data were well fit with an exponential function. We found DLP-normalized organ dose to correlate strongly with body diameter (R{sup 2}>0.95 for most organs). Similarly, we found a very strong correlation with body diameter for DLP-normalized effective dose (R{sup 2}>0.99). Our results were compared to other studies and we found average agreement of approximately 10%. We provide organ and effective doses for a total of 80 reference phantoms representing normal-stature children ranging in age and body size. This information will be valuable in replacing the types of vendor-reported doses available. These data will also permit the recording and tracking of individual patient doses. Moreover, this comprehensive dose database will facilitate patient matching and the ability to predict patient-individualized dose prior to examination. (orig.)

  2. Effect of titanium dental implants on proton therapy delivered for head tumors: experimental validation using an anthropomorphic head phantom

    Czech Academy of Sciences Publication Activity Database

    Oancea, Cristina; Shipulin, K.; Mytsin, G. V.; Molokanov, A. G.; Niculae, D.; Ambrožová, Iva; Davídková, Marie

    2017-01-01

    Roč. 12, MAR (2017), č. článku C03082. ISSN 1748-0221 R&D Projects: GA MŠk LG14004 Institutional support: RVO:61389005 Keywords : dosimetry concepts and apparatus * instrumentation for hadron therapy * microdosimetry and nanodosimetry * particle tracking detectors (solid-state detectors) Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders OBOR OECD: Nuclear physics Impact factor: 1.220, year: 2016

  3. Digital tomosynthesis for verifying spine position during radiotherapy: a phantom study

    Science.gov (United States)

    Gurney-Champion, Oliver J.; Dahele, Max; Mostafavi, Hassan; Slotman, Ben J.; Verbakel, Wilko F. A. R.

    2013-08-01

    Monitoring the stability of patient position is essential during high-precision radiotherapy such as spine stereotactic body radiotherapy (SBRT). We evaluated the combination of digital tomosynthesis (DTS) and triangulation for spine position detection, using non-clinical DTS software and an anthropomorphic pelvic phantom that includes a bone-like spine structure. Kilovoltage cone beam CT projection images over 2-16° gantry rotation were used to generate single slice DTS images. Each DTS slice was registered to a digitally reconstructed DTS derived from the planning CT scan to determine 2D shifts between actual phantom and treatment plan position. Two or more DTS registrations, central axes 4-22° apart, were triangulated to determine the 3D phantom position. Using sequentially generated DTS images, the phantom position can be updated every degree with a small latency of DTS and triangulation angle. The precision of position determination was investigated as function of DTS and triangulation angle. To mimic the scenario of spine SBRT, the effect on the standard deviation of megavoltage radiation delivery during kV image acquisition was tested. In addition, the ability of the system to detect different types of movement was investigated for a variety of small sudden and gradual movements during kV image acquisition.

  4. Phantom Validation of Tc-99m Absolute Quantification in a SPECT/CT Commercial Device

    Directory of Open Access Journals (Sweden)

    Silvano Gnesin

    2016-01-01

    Full Text Available Aim. Similar to PET, absolute quantitative imaging is becoming available in commercial SPECT/CT devices. This study’s goal was to assess quantitative accuracy of activity recovery as a function of image reconstruction parameters and count statistics in a variety of phantoms. Materials and Methods. We performed quantitative Tc99m-SPECT/CT acquisitions (Siemens Symbia Intevo, Erlangen, Germany of a uniform cylindrical, NEMA/IEC, and an anthropomorphic abdominal phantom. Background activity concentrations tested ranged: 2–80 kBq/mL. SPECT acquisitions used 120 projections (20 s/projection. Reconstructions were performed with the proprietary iterative conjugate gradient algorithm. NEMA phantom reconstructions were obtained as a function of the iteration number (range: 4–48. Recovery coefficients, hot contrast, relative lung error (NEMA phantom, and image noise were assessed. Results. In all cases, absolute activity and activity concentration were measured within 10% of the expected value. Recovery coefficients and hot contrast in hot inserts did not vary appreciably with count statistics. RC converged at 16 iterations for insert size > 22 mm. Relative lung errors were comparable to PET levels indicating the efficient integration of attenuation and scatter corrections with adequate detector modeling. Conclusions. The tested device provided accurate activity recovery within 10% of correct values; these performances are comparable to current generation PET/CT systems.

  5. Digital tomosynthesis for verifying spine position during radiotherapy: a phantom study

    International Nuclear Information System (INIS)

    Gurney-Champion, Oliver J; Dahele, Max; Slotman, Ben J; Verbakel, Wilko F A R; Mostafavi, Hassan

    2013-01-01

    Monitoring the stability of patient position is essential during high-precision radiotherapy such as spine stereotactic body radiotherapy (SBRT). We evaluated the combination of digital tomosynthesis (DTS) and triangulation for spine position detection, using non-clinical DTS software and an anthropomorphic pelvic phantom that includes a bone-like spine structure. Kilovoltage cone beam CT projection images over 2–16° gantry rotation were used to generate single slice DTS images. Each DTS slice was registered to a digitally reconstructed DTS derived from the planning CT scan to determine 2D shifts between actual phantom and treatment plan position. Two or more DTS registrations, central axes 4–22° apart, were triangulated to determine the 3D phantom position. Using sequentially generated DTS images, the phantom position can be updated every degree with a small latency of DTS and triangulation angle. The precision of position determination was investigated as function of DTS and triangulation angle. To mimic the scenario of spine SBRT, the effect on the standard deviation of megavoltage radiation delivery during kV image acquisition was tested. In addition, the ability of the system to detect different types of movement was investigated for a variety of small sudden and gradual movements during kV image acquisition. (paper)

  6. Mathematically defined phantoms for organ dose calculation

    International Nuclear Information System (INIS)

    Saito, Kimiaki

    1998-01-01

    There are physical and mathematical phantoms which, for simulating the radiation reactions in the body, composed from more than one tissue equivalent material(s). This review concerns the latter one, particularly the human phantom, for its characteristics, actual models, examples of dose calculation and problems in future. The human phantom is classified into the formula phantom where sizes and properties of human organs/tissues are expressed by the combination of formula, and the voxel phantom where they are expressed by the combination of small cubes (voxel). The formula phantom usually uses quadratic equations for expressing the organ shape and was firstly developed as a MIRD (Medical Internal Radiation Dose Committee)-5 phantom. Based on the MIRD-5, many versions such as female, male and child phantoms have been developed. Voxel phantoms are rather new and are based on CT data of a person. Both phantoms require human numerical data: e.g., from reference man for formula phantom and actual precise CT data for voxel phantom. Dose calculation revealed that, for the low energy photon, doses are rather different between the two phantoms. Future problems involve the further examination on the size and properties of organs, improvement of expression of the phantoms, preparation of standard phantoms, modulation and simplification of the procedure for preparing the voxel phantom and an idea for automatic construction of the human phantom with appropriate parameters. (K.H.)

  7. Construction of anthropomorphic hybrid, dual-lattice voxel models for optimizing image quality and dose in radiography

    Science.gov (United States)

    Petoussi-Henss, Nina; Becker, Janine; Greiter, Matthias; Schlattl, Helmut; Zankl, Maria; Hoeschen, Christoph

    2014-03-01

    In radiography there is generally a conflict between the best image quality and the lowest possible patient dose. A proven method of dosimetry is the simulation of radiation transport in virtual human models (i.e. phantoms). However, while the resolution of these voxel models is adequate for most dosimetric purposes, they cannot provide the required organ fine structures necessary for the assessment of the imaging quality. The aim of this work is to develop hybrid/dual-lattice voxel models (called also phantoms) as well as simulation methods by which patient dose and image quality for typical radiographic procedures can be determined. The results will provide a basis to investigate by means of simulations the relationships between patient dose and image quality for various imaging parameters and develop methods for their optimization. A hybrid model, based on NURBS (Non Linear Uniform Rational B-Spline) and PM (Polygon Mesh) surfaces, was constructed from an existing voxel model of a female patient. The organs of the hybrid model can be then scaled and deformed in a non-uniform way i.e. organ by organ; they can be, thus, adapted to patient characteristics without losing their anatomical realism. Furthermore, the left lobe of the lung was substituted by a high resolution lung voxel model, resulting in a dual-lattice geometry model. "Dual lattice" means in this context the combination of voxel models with different resolution. Monte Carlo simulations of radiographic imaging were performed with the code EGS4nrc, modified such as to perform dual lattice transport. Results are presented for a thorax examination.

  8. Active phantoms: a paradigm for ultrasound calibration using phantom feedback.

    Science.gov (United States)

    Cheng, Alexis; Guo, Xiaoyu; Zhang, Haichong K; Kang, Hyun Jae; Etienne-Cummings, Ralph; Boctor, Emad M

    2017-07-01

    In ultrasound (US)-guided medical procedures, accurate tracking of interventional tools is crucial to patient safety and clinical outcome. This requires a calibration procedure to recover the relationship between the US image and the tracking coordinate system. In literature, calibration has been performed on passive phantoms, which depend on image quality and parameters, such as frequency, depth, and beam-thickness as well as in-plane assumptions. In this work, we introduce an active phantom for US calibration. This phantom actively detects and responds to the US beams transmitted from the imaging probe. This active echo (AE) approach allows identification of the US image midplane independent of image quality. Both target localization and segmentation can be done automatically, minimizing user dependency. The AE phantom is compared with a crosswire phantom in a robotic US setup. An out-of-plane estimation US calibration method is also demonstrated through simulation and experiments to compensate for remaining elevational uncertainty. The results indicate that the AE calibration phantom can have more consistent results across experiments with varying image configurations. Automatic segmentation is also shown to have similar performance to manual segmentation.

  9. Do Young Chinese Children Gain Anthropomorphism after Exposure to Personified Touch-Screen and Board Games?

    Science.gov (United States)

    Li, Hui; Hsueh, Yeh; Wang, Fuxing; Bai, Xuejun; Liu, Tao; Zhou, Li

    2017-01-01

    Research shows that preschoolers are likely to anthropomorphize not only animals, but also inanimate toy after being exposed to books that personify these objects. Can such an effect also arise through young children's use of touch-screen games? The present study is the first to examine whether playing a touch-screen personified train game affects young children's anthropomorphism of real trains. Seventy-nine 4- and 6-year-old children were randomly assigned to play either a touch-screen game or a board game of Thomas the Tank Engine for 10 min. They completed the Individual Differences in Anthropomorphism Questionnaire-Child Form (IDAQ-CF) (two subscales: Technology/Inanimate Nature, Animate Nature) and an additional four items about the anthropomorphism of real trains, before (T1) and after (T2) the game. Overall results showed that children manifested a small but statistically significant increase in anthropomorphizing of real trains after their exposure to both games, claiming that real trains were like humans. Interestingly, 4-year-old children in the board game group tended to anthropomorphize real trains more than those in the touch-screen group, whereas the reverse was true for the 6-year-old children. The results suggest that touch-screen games may delay the decline of children's anthropomorphism during the cognitive and socio-emotional transition that occurs in children aged 5-7. These findings have implications for future research on how touch-screen games increase children's anthropomorphism of the real world, and more generally, for evaluation of the influence of the growing use of touch-screen games on young children's learning.

  10. Validation of a Monte Carlo model used for simulating tube current modulation in computed tomography over a wide range of phantom conditions/challenges

    Energy Technology Data Exchange (ETDEWEB)

    Bostani, Maryam, E-mail: mbostani@mednet.ucla.edu; McMillan, Kyle; Cagnon, Chris H.; McNitt-Gray, Michael F. [Departments of Biomedical Physics and Radiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90024 (United States); DeMarco, John J. [Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, California 90095 (United States)

    2014-11-01

    Purpose: Monte Carlo (MC) simulation methods have been widely used in patient dosimetry in computed tomography (CT), including estimating patient organ doses. However, most simulation methods have undergone a limited set of validations, often using homogeneous phantoms with simple geometries. As clinical scanning has become more complex and the use of tube current modulation (TCM) has become pervasive in the clinic, MC simulations should include these techniques in their methodologies and therefore should also be validated using a variety of phantoms with different shapes and material compositions to result in a variety of differently modulated tube current profiles. The purpose of this work is to perform the measurements and simulations to validate a Monte Carlo model under a variety of test conditions where fixed tube current (FTC) and TCM were used. Methods: A previously developed MC model for estimating dose from CT scans that models TCM, built using the platform of MCNPX, was used for CT dose quantification. In order to validate the suitability of this model to accurately simulate patient dose from FTC and TCM CT scan, measurements and simulations were compared over a wide range of conditions. Phantoms used for testing range from simple geometries with homogeneous composition (16 and 32 cm computed tomography dose index phantoms) to more complex phantoms including a rectangular homogeneous water equivalent phantom, an elliptical shaped phantom with three sections (where each section was a homogeneous, but different material), and a heterogeneous, complex geometry anthropomorphic phantom. Each phantom requires varying levels of x-, y- and z-modulation. Each phantom was scanned on a multidetector row CT (Sensation 64) scanner under the conditions of both FTC and TCM. Dose measurements were made at various surface and depth positions within each phantom. Simulations using each phantom were performed for FTC, detailed x–y–z TCM, and z-axis-only TCM to obtain

  11. Validation of a Monte Carlo model used for simulating tube current modulation in computed tomography over a wide range of phantom conditions/challenges.

    Science.gov (United States)

    Bostani, Maryam; McMillan, Kyle; DeMarco, John J; Cagnon, Chris H; McNitt-Gray, Michael F

    2014-11-01

    Monte Carlo (MC) simulation methods have been widely used in patient dosimetry in computed tomography (CT), including estimating patient organ doses. However, most simulation methods have undergone a limited set of validations, often using homogeneous phantoms with simple geometries. As clinical scanning has become more complex and the use of tube current modulation (TCM) has become pervasive in the clinic, MC simulations should include these techniques in their methodologies and therefore should also be validated using a variety of phantoms with different shapes and material compositions to result in a variety of differently modulated tube current profiles. The purpose of this work is to perform the measurements and simulations to validate a Monte Carlo model under a variety of test conditions where fixed tube current (FTC) and TCM were used. A previously developed MC model for estimating dose from CT scans that models TCM, built using the platform of mcnpx, was used for CT dose quantification. In order to validate the suitability of this model to accurately simulate patient dose from FTC and TCM CT scan, measurements and simulations were compared over a wide range of conditions. Phantoms used for testing range from simple geometries with homogeneous composition (16 and 32 cm computed tomography dose index phantoms) to more complex phantoms including a rectangular homogeneous water equivalent phantom, an elliptical shaped phantom with three sections (where each section was a homogeneous, but different material), and a heterogeneous, complex geometry anthropomorphic phantom. Each phantom requires varying levels of x-, y- and z-modulation. Each phantom was scanned on a multidetector row CT (Sensation 64) scanner under the conditions of both FTC and TCM. Dose measurements were made at various surface and depth positions within each phantom. Simulations using each phantom were performed for FTC, detailed x-y-z TCM, and z-axis-only TCM to obtain dose estimates. This

  12. Validation of a Monte Carlo model used for simulating tube current modulation in computed tomography over a wide range of phantom conditions/challenges

    International Nuclear Information System (INIS)

    Bostani, Maryam; McMillan, Kyle; Cagnon, Chris H.; McNitt-Gray, Michael F.; DeMarco, John J.

    2014-01-01

    Purpose: Monte Carlo (MC) simulation methods have been widely used in patient dosimetry in computed tomography (CT), including estimating patient organ doses. However, most simulation methods have undergone a limited set of validations, often using homogeneous phantoms with simple geometries. As clinical scanning has become more complex and the use of tube current modulation (TCM) has become pervasive in the clinic, MC simulations should include these techniques in their methodologies and therefore should also be validated using a variety of phantoms with different shapes and material compositions to result in a variety of differently modulated tube current profiles. The purpose of this work is to perform the measurements and simulations to validate a Monte Carlo model under a variety of test conditions where fixed tube current (FTC) and TCM were used. Methods: A previously developed MC model for estimating dose from CT scans that models TCM, built using the platform of MCNPX, was used for CT dose quantification. In order to validate the suitability of this model to accurately simulate patient dose from FTC and TCM CT scan, measurements and simulations were compared over a wide range of conditions. Phantoms used for testing range from simple geometries with homogeneous composition (16 and 32 cm computed tomography dose index phantoms) to more complex phantoms including a rectangular homogeneous water equivalent phantom, an elliptical shaped phantom with three sections (where each section was a homogeneous, but different material), and a heterogeneous, complex geometry anthropomorphic phantom. Each phantom requires varying levels of x-, y- and z-modulation. Each phantom was scanned on a multidetector row CT (Sensation 64) scanner under the conditions of both FTC and TCM. Dose measurements were made at various surface and depth positions within each phantom. Simulations using each phantom were performed for FTC, detailed x–y–z TCM, and z-axis-only TCM to obtain

  13. A numerical model for blast injury of human thorax based on digitized visible human.

    Science.gov (United States)

    Li, Xiao-Fang; Kuang, Jiang-Ming; Nie, Si-Bing; Xu, Jing; Zhu, Jin; Liu, Yi-He

    2017-12-04

    Knowledge of the pressure distribution around human thorax in blast help to understand the injury mechanisms and their assessment. To investigate the transmission mechanism of the pressure on human thorax in blast, a three dimension surface model of human thorax was constructed in this work. To increase the precious of this model, tetrahedron element division method was applied to transfer the rough 3D surface model to hexahedral elements model. Using this model, the high pressure duration was computationally solved using numerical simulation of the hexahedral elements. Simulation results showed that the apex of lungs was subjected to the largest stress in a blast. In order to verify this result, an animal experiment was performed on a dog. The animal experimental results was shown to have a same variation tendency with the calculation results based on our numerical model of human thorax, which made this model reliable for the blast injury research.

  14. A case of posttraumatic splenic translocation into the thorax; Przypadek pourazowego przemieszczenia sledziony do klatki piersiowej

    Energy Technology Data Exchange (ETDEWEB)

    Sosnowski, P.; Sikorski, L.; Ziemianski, A. [Akademia Medyczna, Poznan (Poland)

    1993-12-31

    A case of the left diaphragmatic hernia due to blunt thoracic and abdominal trauma is presented. Characteristic radiological signs of splenic translocation into the thorax contributed to quick diagnosis and immediate surgical intervention. (author). 5 refs, 2 figs.

  15. Application of Lead Field Theory and Computerized Thorax Modeling for the ECG Inverse Problem

    National Research Council Canada - National Science Library

    Puurtinen, H

    2001-01-01

    .... In this study, one anatomically detailed 3D FDM model of the human thorax as a volume conductor was employed for forward and inverse estimation of ECG potentials and cardiac sources, respectively...

  16. Modeling the Biodynamical Response of the Human Thorax with Body Armor from a Bullet Impact

    National Research Council Canada - National Science Library

    Lobuono, John

    2001-01-01

    .... The finite element model of the human thorax is validated by comparing the model's results to experimental data obtained from cadavers wearing a protective body armor system undergoing a projectile impact...

  17. Modeling the Biodynamical Response of the Human Thorax With Body Armor From a Bullet Impact

    National Research Council Canada - National Science Library

    Lobuono, John

    2001-01-01

    .... The finite element model of the human thorax is validated by comparing the model's results to experimental data obtained from cadavers wearing a protective body armor system undergoing a projectile impact...

  18. Phantom stars and topology change

    International Nuclear Information System (INIS)

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

    2008-01-01

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

  19. 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)

    Hegenbart, Lars

    2010-01-01

    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.)

  20. 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.

  1. Clinical applications of the computed tomography of the thorax

    International Nuclear Information System (INIS)

    Hong, Seong Eun; Kim, Ho Kyun; Kim, Soon Yong

    1980-01-01

    The computed tomography of the thorax has had considerably less impact in patient management than that of head and abdomen, because the convention chest radiography is a much more sensitive and accurate examination than the plain film studies of the head and abdomen. It has progressively been identified that the computed tomography of chest is superior to the conventional radiography in detection of small pulmonary nodules including occult metastatic lesions, in evaluation of character of hilar enlargement, and in staging of known bronchogenic caner. And especially in mediastinum, the computed tomography is supported to the any other conventional radiography in outlining lesions and determining character and extent of lesions. At the department of radiology, Kyung Hee University Hospital , 87 cases of computed tomography of chest were performed with EMI-CT 5005 whole-body scanner from October 1977 to August 1979. The results were as following; 1. The fifty eight cases of considered to be pathologic findings were 23 pleural thickening and/or effusion, 14 bronchogenic carcinoma, 8 inflammatory lesions of lung parenchyme, 6 mediastinal lesions, 3 metastinal lesions, 3 COPD, 1 trauma, respectively. 2. No gravity-dependent change was noted in patients with chronic obstructive pulmonary disease (COPD), which was frequently seen in normal subjects. Diminished numbers of pulmonary vessels was noted in COPD. 3. Small nodules in lung, retrosternal, posterior costophrenic and subpleural regions, which were not found on conventional radiography, can be detected by chest CT. 4. Differentiation of dilated central pulmonary artery from pulmonary mass in enlarged hilum and determination of adjacent mediastinal invasion, manifested by obliterated fat plane, was possible. 5. The cases of mediastinal widening such as paraspinal ilpomatosis, pericardial fat pad, teratoma, and bronchogenic cyst were easily determined by means of measuring the attenuation coefficiencies. 6. Small amount

  2. An improved Virtual Torso phantom

    International Nuclear Information System (INIS)

    Kramer, Gary H; Crowley, Paul

    2000-01-01

    The virtual phantom that was previously designed by the Human Monitoring Laboratory had some limitations. It contained no sternum and the ribs extended all the way round the torso, whereas in reality the central part of the chest is covered with a mixture of cartilage (ribs) and bone (sternum). The ribs were located below the chest wall which added to the thickness of the chest wall. The lungs did not touch the inner surface of the chest wall along their length due to the differences in curvature between the ellipsoidal lungs and the ellipsoidal cylinder that defined the torso. As a result there was extra intervening tissue between the lungs and the chest wall. This was shown to have a noticeable effect on the simulation of low energy photons. The virtual phantom has been redesigned and comparison of measured and calculated counting efficiencies shows that it is a good representation of both of LLNL or JAERI at all photon energies measured. The redesigned virtual phantom agrees to within 11% of the torsos' counting efficiency over the energy range 17 - 240 keV. Before modification, the virtual phantom's counting efficiency was a of factor three lower at 17 keV and a factor of two lower at 20 keV; now it is within 5% at 17 keV and within 10% at 20 keV. This phantom can now be reliably used to simulate lung counting. The virtual phantom still contains no sternum and the ribs extend all the way round the torso, whereas in reality the central part of the chest is covered with cartilage (ribs) and bone (sternum). However, the above results indicate that this is not a major flaw in the design of the virtual phantom, as agreement between the Monte Carlo results and experimental data is good. (author)

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

    International Nuclear Information System (INIS)

    Leal Neto, Viriato; Vieira, Jose W.; Lima, Fernando R.A.; Lima, Lindeval F.

    2011-01-01

    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)

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

    International Nuclear Information System (INIS)

    Jansen, Jan T.M.; Shrimpton, Paul C.

    2010-01-01

    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)

  5. 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)

  6. Optimization of the quality and dose in thorax general radiology

    International Nuclear Information System (INIS)

    Hwang, Suy Ferreira

    2001-01-01

    Image quality and radiation dose at skin entrance in chest radiography were studied for three exposure protocols, denoted as 1, 2 and 3. Protocol 1 represents the most used technique in radiology services in our country. This technique consists of the following parameters: 81 kV tube voltage, anti-scatter grid and 2 m focus-film distance. Protocol 2 uses the same parameters of the Protocol 1, without grid. Protocol 3 uses I 33kV without grid and 3,5 m focus-film distance. In Protocols 2 and 3 a 30 em air gap was used between patient and film. Two samples of 50 patients were radiographed in two different facilities, herein denoted 1 and 2. Protocol 1 was used in facility I to radiograph the first patient sample, and Protocols 2 and 3 were used in facility 2 to radiograph the second patient sample. Three experts in chest radiology evaluated the obtained chest images according anatomical quality criteria for this examination. For each patient exposure the radiation dose at skin entrance was measured. In this work, a chest phantom, containing test objects to evaluate quantitatively image quality, was made. The phantom was radiographed with the three protocols herein investigated. Results of this study showed clearly that Protocol 3 presents an average dose at skin entrance about half than Protocol 2 and about one third of Protocol 1. In regard to chest radiographic images and radiation dose, it was statistically demonstrated that the Protocol 3 is better than Protocols 1 and 2, with the improvement of the image quality and patient dose reduction in order of 3 times. This work also discusses the perspective of using optimized exposure technique proposed by Protocol 3 as an alternative technique far chest radiographic examinations to those currently used in our diagnostic radiology facilities. (author)

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

    Science.gov (United States)

    Ganea, Patricia A.; Canfield, Caitlin F.; Simons-Ghafari, Kadria; Chou, Tommy

    2013-01-01

    Many books for young children present animals in fantastical and unrealistic ways, such 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. PMID:24782793

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

    Science.gov (United States)

    Ganea, Patricia A; Canfield, Caitlin F; Simons-Ghafari, Kadria; Chou, Tommy

    2014-01-01

    Many books for young children present animals in fantastical and unrealistic ways, such 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.

  9. Anxious attachment and excessive acquisition: The mediating roles of anthropomorphism and distress intolerance.

    Science.gov (United States)

    Norberg, Melissa M; Crone, Cassandra; Kwok, Cathy; Grisham, Jessica R

    2018-03-01

    Background and aims Most individuals with hoarding disorder (HD) are prone to excessively acquiring new possessions. Understanding the factors that contribute to this collecting behavior will allow us to develop better treatment approaches for HD. The aim of this study was to test our assumption that an anxious attachment style is associated with a tendency to anthropomorphize comforting objects and an inability to tolerate distress, which in turn leads to excessive acquisition. Methods A total of 361 participants with subclinical to clinical acquisition problems (77.8% female) completed a series of self-report measures. Results As expected, greater anxious attachment was related to greater distress intolerance and stronger tendencies to anthropomorphize inanimate objects. In turn, greater distress intolerance and anthropomorphism were related to more excessive buying and greater acquisition of free items. Examination of the pathways and indirect effects showed support for double mediation rather than serial mediation, as distress intolerance did not predict anthropomorphism. Discussion and conclusion These novel findings, if replicated, suggest that adding treatment modules that target improving distress tolerance and reducing anthropomorphism to standard treatment for HD may lead to further reductions in excessive acquiring.

  10. Experimental dosimetric evaluation in pelvis phantom, subjected to prostate radiation therapy protocol at 15 MV Linac

    International Nuclear Information System (INIS)

    Matos, Andrea Silva Dias de; Campos, Tarcisio P.R.

    2011-01-01

    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)

  11. 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)

  12. Development of a voxel phantom specific for simulation of eye brachytherapy

    International Nuclear Information System (INIS)

    Santos, Marcilio S.; Lima, Fernando R.A.

    2013-01-01

    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

  13. 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.)

  14. Effects of anthropomorphic images and narration styles in promotional messages for generic prescription drugs.

    Science.gov (United States)

    Muzumdar, Jagannath M; Schommer, Jon C; Hadsall, Ronald S; Huh, Jisu

    2013-01-01

    Anthropomorphism is attribution of human characteristics to nonhuman objects or events. Marketers have used anthropomorphized characters to promote products and services. To promote use of generic drugs to save on prescription drug costs, health systems are in the process of developing informational materials to influence consumer's perceptions about generic prescription drugs. To evaluate the effects of anthropomorphic images (control vs caring vs authoritative) and information narration styles (first person vs third person) on (1) social presence, (2) attitude toward the overall promotional message, (3) perceived informativeness of the message content, (4) attitude toward specific message, (5) intent to seek information, and (6) intention to switch to a generic prescription drug. A 3×2 between-subject factorial design was used. Student participants were administered a mock promotional message regarding generic prescription drugs. Following the promotional message, they were asked to respond to items developed to measure the effects of the promotional message. Manipulation checks were conducted to test the desired effects of the independent variables. Pilot testing, exploratory factor analysis, and reliability testing of the item measures were conducted before their use in the study. Analysis of variance was used to analyze the data and test the proposed effects of the independent variables. Anthropomorphic images showed a positive effect on social presence and attitude toward the specific message. Narration styles had a positive effect on attitude toward the overall promotional message. Neither anthropomorphic images nor narration styles had a significant effect on perceived informativeness, intent to seek information, and intention to switch to a generic prescription drug. This research reveals that anthropomorphism of medications and narration styles could play a significant role in promotional messages for generic prescription drugs. These findings provide a

  15. Phantom pain : A sensitivity analysis

    NARCIS (Netherlands)

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

    2004-01-01

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

  16. Generating human-like movements on an anthropomorphic robot using an interior point method

    Science.gov (United States)

    Costa e Silva, E.; Araújo, J. P.; Machado, D.; Costa, M. F.; Erlhagen, W.; Bicho, E.

    2013-10-01

    In previous work we have presented a model for generating human-like arm and hand movements on an anthropomorphic robot involved in human-robot collaboration tasks. This model was inspired by the Posture-Based Motion-Planning Model of human movements. Numerical results and simulations for reach-to-grasp movements with two different grip types have been presented previously. In this paper we extend our model in order to address the generation of more complex movement sequences which are challenged by scenarios cluttered with obstacles. The numerical results were obtained using the IPOPT solver, which was integrated in our MATLAB simulator of an anthropomorphic robot.

  17. 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.

  18. Chest tube placement in thorax trauma - comparison chest X-ray and computed tomography (CT)

    International Nuclear Information System (INIS)

    Heim, P.; Maas, R.; Buecheler, E.; Tesch, C.

    1998-01-01

    Estimation of chest tube placement in patients with thoracic trauma with regard to chest tube malposition in chest radiography in the supine position compared to additional computed tomography of the thorax. Material and methods: Apart from compulsory chest radiography after one or multiple chest tube insertions, 31 severely injured patients with thoracic trauma underwent a CT scan of the thorax. These 31 patients with 40 chest tubes constituted the basis for the present analysis. Results: In chest radiography in the supine position there were no chest tube malpositions (n=40); In the CT scans 25 correct positions, 7 pseudo-malpositions, 6 intrafissural and 2 intrapulmonary malpositions were identified. Moreover 16 sufficient, 18 insufficient and 6 indifferent functions of the chest tubes were seen. Conclusion: In case of lasting clinical problems and questionable function of the chest tube, chest radiography should be supplemented by a CT scan of the thorax in order to estimate the position of the chest tube. (orig.) [de

  19. 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.  

  20. Development of Adjustable 3D computational phantoms for breast radiotherapy

    International Nuclear Information System (INIS)

    Emam, Zohal Alnour Ahmed

    2016-06-01

    Radiotherapy has become an essential part of breast cancer treatment and it was given a great concern during last decades due to aspects of managing breast cancer successfully, reducing recurrence and breast cancer mortality. Monte Carlo simulation has been used heavily in this issue. To use monte Carlo the suitable data set must be found to perform the study. This process is not straight forward and difficult to achieve and an effort is needed to obtain it. In this work we aimed to develop a methodology for obtaining 3D adjustable computational phantoms with different breast sizes to treat this problem. At first make human software was used to generate outer surfaces models with desired anthropomorphic features for our purpose. Three breasts cup sizes have been developed: small (A), medium (C) and large (D) according to European standardization system of dress, then blender software was used to join skeleton and internal organs outer surfaces of the body models in correct anatomical positions and the results were poly mesh anthropomorphic phantom has three breast sizes easy to manipulate positioning and modifying, the prepared models have been voxelised in 3D matrixes (256*256*256) using Binvox software, then voxelised models prepared in suitable formats for Gate (mhd/raw) in 70 axial slice with voxel dimension of 1.394*1.394*5 mm 3 for width, depth and length respectively. Gate monte Carlo was used to simulate the irradiation of virtual tumor bed site in left breasts with direct field electron beam, each breast size was treated with five energies 6, 9, 12, 15, and 18 MeV by field size 5*5 cm 2 , and 100 cm source surface distance (SSD). The results were studied to evaluate the effect of breast size variation on dose distribution. According to criteria of tumor bed coverage by 100% 90% normalised maximum dose and minimum dose to heart and lug which are considering the organs at risks, results show the energy 6 MeV give under cover to tumor bed in the small, medium

  1. 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…

  2. 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)

  3. Application of digital image processing for the generation of voxels phantoms for Monte Carlo simulation.

    Science.gov (United States)

    Boia, L S; Menezes, A F; Cardoso, M A C; da Rosa, L A R; Batista, D V S; Cardoso, S C; Silva, A X; Facure, A

    2012-01-01

    This paper presents the application of a computational methodology for optimizing the conversion of medical tomographic images in voxel anthropomorphic models for simulation of radiation transport using the MCNP code. A computational system was developed for digital image processing that compresses the information from the DICOM medical image before it is converted to the Scan2MCNP software input file for optimization of the image data. In order to validate the computational methodology, a radiosurgery treatment simulation was performed using the Alderson Rando phantom and the acquisition of DICOM images was performed. The simulation results were compared with data obtained with the BrainLab planning system. The comparison showed good agreement for three orthogonal treatment beams of (60)Co gamma radiation. The percentage differences were 3.07%, 0.77% and 6.15% for axial, coronal and sagital projections, respectively. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. 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.

  5. A biomechanical study regarding the effect of tissue harvesting from the thorax on its movement during inspiration.

    Science.gov (United States)

    Hatano, Asako; Nagasao, Tomohisa; Shimizu, Yusuke; Jin, Hongmei; Kaneko, Tsuyoshi; Cho, Yasunori; Jiang, Hua; Kishi, Kazuo

    2013-01-01

    In the practice of plastic surgery, ribs and cartilage are often harvested for use in auto-grafts. This study aimed to elucidate the effect of such harvesting on the inspiration movement of the thorax. Sixteen three-dimensional computer simulation models were produced by reference to the CT data of 16 patients. To simulate the harvesting of ribs and costal cartilages, parts were removed from these thorax models, thereby producing models with different types of defect. By performing finite element calculation after applying contracture forces on the external intercostal muscles and diaphragm, the movement patterns exhibited by the thoraces during inspiration were analyzed. The relationships between the defect types and the movement patterns were evaluated with reference to the dynamic behavior of the sternum and the increase in thoracic volume. Although the removal of costal cartilage can cause asymmetric movement of the thorax, it did not affect the inspiration movement of the thorax. However, removal of two or more ribs not only caused asymmetric movement of the thorax, but also negatively affected that movement. Removal of two or three ribs impaired the expansion of the hemi-thorax on inspiration by 10% and 40%, respectively. The present study is the first to clarify the quantitative effect of tissue harvesting from the thorax on inspiration. The findings will be useful for surgeons when planning operations requiring harvesting of tissue from the thorax.

  6. NMR-CT image and symbol phantoms

    International Nuclear Information System (INIS)

    Hongo, Syozo; Yamaguchi, Hiroshi; Takeshita, Hiroshi

    1990-01-01

    We have developed Japanese phantoms in two procedures. One is described as a mathematical expression. Another is 'symbol phantoms' in 3 dimensional picture-elements, each of which symbolize an organ name. The concept and the algorithm of the symbol phantom enables us to make a phantom for a individual in terms of all his transversal section images. We got 85 transversal section images of head and trunk parts, and those of 40 legs parts by using NMR-CT. We have made the individual phantom for computation of organ doses. The transversal section images were not so clear to identify all organs needed to dose estimation that we had to do hand-editing the shapes of organs with viewing a typical section images: we could not yet make symbol phantom in a automatic editing. Symbols were coded to be visual cords as ASCII characters. After we got the symbol phantom of the first stage, we can edit it easily using a word-processor. Symbol phantom could describe more freely the shape of organs than mathematical phantom. Symbol phantom has several advantages to be an individual phantom, but the only difficult point is how to determine its end-point as a reference man when we apply the method to build the reference man. (author)

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

    Science.gov (United States)

    Kühn, Simone; Brick, Timothy R; Müller, Barbara C N; Gallinat, Jürgen

    2014-01-01

    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.

  8. 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. © The Author(s) 2010.

  9. 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

  10. TH-CD-202-07: A Methodology for Generating Numerical Phantoms for Radiation Therapy Using Geometric Attribute Distribution Models

    International Nuclear Information System (INIS)

    Dolly, S; Chen, H; Mutic, S; Anastasio, M; Li, H

    2016-01-01

    Purpose: A persistent challenge for the quality assessment of radiation therapy treatments (e.g. contouring accuracy) is the absence of the known, ground truth for patient data. Moreover, assessment results are often patient-dependent. Computer simulation studies utilizing numerical phantoms can be performed for quality assessment with a known ground truth. However, previously reported numerical phantoms do not include the statistical properties of inter-patient variations, as their models are based on only one patient. In addition, these models do not incorporate tumor data. In this study, a methodology was developed for generating numerical phantoms which encapsulate the statistical variations of patients within radiation therapy, including tumors. Methods: Based on previous work in contouring assessment, geometric attribute distribution (GAD) models were employed to model both the deterministic and stochastic properties of individual organs via principle component analysis. Using pre-existing radiation therapy contour data, the GAD models are trained to model the shape and centroid distributions of each organ. Then, organs with different shapes and positions can be generated by assigning statistically sound weights to the GAD model parameters. Organ contour data from 20 retrospective prostate patient cases were manually extracted and utilized to train the GAD models. As a demonstration, computer-simulated CT images of generated numerical phantoms were calculated and assessed subjectively and objectively for realism. Results: A cohort of numerical phantoms of the male human pelvis was generated. CT images were deemed realistic both subjectively and objectively in terms of image noise power spectrum. Conclusion: A methodology has been developed to generate realistic numerical anthropomorphic phantoms using pre-existing radiation therapy data. The GAD models guarantee that generated organs span the statistical distribution of observed radiation therapy patients

  11. Compound analysis of gallstones using dual energy computed tomography-Results in a phantom model

    International Nuclear Information System (INIS)

    Bauer, Ralf W.; Schulz, Julian R.; Zedler, Barbara; Graf, Thomas G.; Vogl, Thomas J.

    2010-01-01

    Purpose: The potential of dual energy computed tomography (DECT) for the analysis of gallstone compounds was investigated. The main goal was to find parameters, that can reliably define high percentage (>70%) cholesterol stones without calcium components. Materials and methods: 35 gallstones were analyzed with DECT using a phantom model. Stone samples were put into specimen containers filled with formalin. Containers were put into a water-filled cylindrical acrylic glass phantom. DECT scans were performed using a tube voltage/current of 140 kV/83 mAs (tube A) and 80 kV/340 mAs (tube B). ROI-measurements to determine CT attenuation of each sector of the stones that had different appearance on the CT images were performed. Finally, semi-quantitative infrared spectroscopy (FTIR) of these sectors was performed for chemical analysis. Results: ROI-measurements were performed in 45 different sectors in 35 gallstones. Sectors containing >70% of cholesterol and no calcium component (n = 20) on FTIR could be identified with 95% sensitivity and 100% specificity on DECT. These sectors showed typical attenuation of -8 ± 4 HU at 80 kV and +22 ± 3 HU at 140 kV. Even the presence of a small calcium component (<10%) hindered the reliable identification of cholesterol components as such. Conclusion: Dual energy CT allows for reliable identification of gallstones containing a high percentage of cholesterol and no calcium component in this pre-clinical phantom model. Results from in vivo or anthropomorphic phantom trials will have to confirm these results. This may enable the identification of patients eligible for non-surgical treatment options in the future.

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

    International Nuclear Information System (INIS)

    Kim, E.Y.; Kim, T.S.; Han, J.; Kim, H.; Choi, Y.S.

    2012-01-01

    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.

  13. Preliminary report on a new mode of CT-scanning of the thorax

    NARCIS (Netherlands)

    Veiga-Pires, J.A.; Kaiser, M.C.

    1980-01-01

    The A.A. advocate a “longitudino-axial” mode of CT-scanning in examinations of the thorax and suggest it as the standard mode in children and adults of small stature. The full development of the method is at present limited by the design of both hardware and software of the current generations of

  14. Computer Modeling and Simulation of Bullet Impact to the Human Thorax

    National Research Council Canada - National Science Library

    Jolly, Johannes

    2000-01-01

    .... The objective of the study was to create a viable finite element model of the human thorax. The model was validated by comparing the results of tests of body armor systems conducted on cadavers to results obtained from finite element analysis...

  15. Surgical treatment of a large congenital cavernous hemangioma on the thorax of a foal

    DEFF Research Database (Denmark)

    Jacobsen, Stine; Christophersen, Mogens Teken; Tnibar, Aziz

    2018-01-01

    A 3-day-old male foal was presented with a fluctuant 25 × 15 cm mass on the thorax. The mass had increased in size since birth. The mass did not respond to conservative treatment consisting of aspiration of serohaemorrhagic contents and compression bandages, and it was therefore surgically remove...

  16. 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…

  17. 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

  18. 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)

    Petroccia, H; O'Reilly, S; Bolch, W; Mendenhall, N; Li, Z; Slopsema, R

    2014-01-01

    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

  19. 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.

  20. 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.

  1. Effect of phantom voxelization in CT simulations

    International Nuclear Information System (INIS)

    Goertzen, Andrew L.; Beekman, Freek J.; Cherry, Simon R.

    2002-01-01

    In computer simulations of x-ray CT systems one can either use continuous geometrical descriptions for phantoms or a voxelized representation. The voxelized approach allows arbitrary phantoms to be defined without being confined to geometrical shapes. The disadvantage of the voxelized approach is that inherent errors are introduced due to the phantom voxelization. To study effects of phantom discretization, analytical CT simulations were run for a fan-beam geometry with phantom voxel sizes ranging from 0.0625 to 2 times the reconstructed pixel size and noise levels corresponding to 10 3 -10 7 photons per detector pixel prior to attenuation. The number of rays traced per detector element was varied from 1 to 16. Differences in the filtered backprojection images caused by changing the phantom matrix sizes and number of rays traced were assessed by calculating the difference between reconstructions based on the finest matrix and coarser matrix simulations. In noise free simulations, all phantom matrix sizes produced a measurable difference in comparison with the finest phantom matrix used. When even a small amount of noise was added to the projection data, the differences due to the phantom discretization were masked by the noise, and in all cases there was almost no improvement by using a phantom matrix that was more than twice as fine as the reconstruction matrix. No substantial improvement was achieved by tracing more than 4 rays per detector pixel

  2. Experimental phantom verification studies for simulations of light interactions with skin: liquid phantoms

    CSIR Research Space (South Africa)

    Karsten, A

    2010-09-01

    Full Text Available phantoms to verify model Slide 5 Verification comparison •Layered structure of skin can be modelled • Solid or liquid phantoms can be used for verification • Solid phantoms prepared from resin, absorbing and scattering particles – advantage: multi... layers possible and phantoms stable and durable for repeatability studies • Liquid samples made from Intralipid® and black ink – optical properties of Intralipid® is well documented in literature •Manufacture phantoms – use phantom parameters...

  3. 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

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

    Science.gov (United States)

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

    2013-10-07

    The International Commission on Radiological Protection (ICRP) reference phantoms, developed based on computed tomography images of human bodies, provide much more realism of human anatomy than the previously used MIRD5 (Medical Internal Radiation Dose) mathematical phantoms. It has been, however, realized that the ICRP reference phantoms have some critical limitations showing a considerable amount of holes for the skin and wall organs mainly due to the nature of voxels of which the phantoms are made, especially due to their low voxel resolutions. To address this problem, we are planning to develop the polygon-surface version of ICRP reference phantoms by directly converting the ICRP reference phantoms (voxel phantoms) to polygon-surface phantoms. The objective of this preliminary study is to see if it is indeed possible to construct the high-quality polygon-surface phantoms based on the ICRP reference phantoms maintaining identical organ morphology and also to identify any potential issues, and technologies to address these issues, in advance. For this purpose, in the present study, the ICRP reference male phantom was roughly converted to a polygon-surface phantom. Then, the constructed phantom was implemented in Geant4, Monte Carlo particle transport code, for dose calculations, and the calculated dose values were compared with those of the original ICRP reference phantom to see how much the calculated dose values are sensitive to the accuracy of the conversion process. The results of the present study show that it is certainly possible to convert the ICRP reference phantoms to surface phantoms with enough accuracy. In spite of using relatively less resources (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

  5. A Software Phantom : Application in Digital Tomosynthesis

    International Nuclear Information System (INIS)

    Lazos, D.; Kolitsi, Z.; Badea, C.; Pallikarakis, N.

    1998-01-01

    A software phantom intended to be used in radiographic applications has been developed. The application was used for research in the field of Digital Tomosynthesis and specifically for studying tomographic noise removal methods. The application consists of a phantom design and a phantom imaging module. The radiation-matter interaction is based on the exponential relation of attenuation. Projections are formed by simulated irradiation with selectable geometrical parameters, source spectrum and detector response. Phantoms are defined either as sets containing certain geometrical objects or as groups of voxels. Comparison with real projections taken from a physical phantom with identical geometry and composition with the simulated one, showed good approximation with improved contrast due to the absence of scatter in the simulated projections. The software phantom proved to be a very useful tool for DTS investigations. Further development to include scatter is expected to expand the use of the application to more areas in radiological imaging research. (author)

  6. 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)

    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.

    2008-01-01

    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 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 absorptive

  7. Neutron dosimetry in solid water phantom

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-11-07

    The neutron spectra, the Kerma and the absorbed dose due to neutrons were estimated along the incoming beam in a solid water phantom. Calculations were carried out with the MCNP5 code, where the bunker, the phantom and the model of the15 MV LINAC head were modeled. As the incoming beam goes into the phantom the neutron spectrum is modified and the dosimetric values are reduced.

  8. Development of a external exposure computational model for studying of input dose in skin for radiographs of thorax and vertebral column

    International Nuclear Information System (INIS)

    Muniz, Bianca C.; Menezes, Claudio J.M.; Vieira, Jose W.

    2014-01-01

    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

  9. 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

  10. 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...

  11. Dental radiography: tooth enamel EPR dose assessment from Rando phantom measurements

    International Nuclear Information System (INIS)

    Aragno, D.; Fattibene, P.; Onori, S.

    2000-01-01

    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 CO 2 -signal of intensity similar to that induced by a dose of about 2 mGy of 60 Co. 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 60 Co. 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)

  12. Application of digital image processing for the generation of voxels phantoms for Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Boia, L.S.; Menezes, A.F.; Cardoso, M.A.C. [Programa de Engenharia Nuclear/COPPE (Brazil); Rosa, L.A.R. da [Instituto de Radioprotecao e Dosimetria-IRD, Av. Salvador Allende, s/no Recreio dos Bandeirantes, CP 37760, CEP 22780-160 Rio de Janeiro, RJ (Brazil); Batista, D.V.S. [Instituto de Radioprotecao e Dosimetria-IRD, Av. Salvador Allende, s/no Recreio dos Bandeirantes, CP 37760, CEP 22780-160 Rio de Janeiro, RJ (Brazil); Instituto Nacional de Cancer-Secao de Fisica Medica, Praca Cruz Vermelha, 23-Centro, 20230-130 Rio de Janeiro, RJ (Brazil); Cardoso, S.C. [Departamento de Fisica Nuclear, Instituto de Fisica, Universidade Federal do Rio de Janeiro, Bloco A-Sala 307, CP 68528, CEP 21941-972 Rio de Janeiro, RJ (Brazil); Silva, A.X., E-mail: ademir@con.ufrj.br [Programa de Engenharia Nuclear/COPPE (Brazil); Departamento de Engenharia Nuclear/Escola Politecnica, Universidade Federal do Rio de Janeiro, Ilha do Fundao, Caixa Postal 68509, 21945-970 Rio de Janeiro, RJ (Brazil); Facure, A. [Comissao Nacional de Energia Nuclear, R. Gal. Severiano 90, sala 409, 22294-900 Rio de Janeiro, RJ (Brazil)

    2012-01-15

    This paper presents the application of a computational methodology for optimizing the conversion of medical tomographic images in voxel anthropomorphic models for simulation of radiation transport using the MCNP code. A computational system was developed for digital image processing that compresses the information from the DICOM medical image before it is converted to the Scan2MCNP software input file for optimization of the image data. In order to validate the computational methodology, a radiosurgery treatment simulation was performed using the Alderson Rando phantom and the acquisition of DICOM images was performed. The simulation results were compared with data obtained with the BrainLab planning system. The comparison showed good agreement for three orthogonal treatment beams of {sup 60}Co gamma radiation. The percentage differences were 3.07%, 0.77% and 6.15% for axial, coronal and sagital projections, respectively. - Highlights: Black-Right-Pointing-Pointer We use a method to optimize the CT image conversion in voxel model for MCNP simulation. Black-Right-Pointing-Pointer We present a methodology to compress a DICOM image before conversion to input file. Black-Right-Pointing-Pointer To validate this study an idealized radiosurgery applied to the Alderson phantom was used.

  13. 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.

  14. Radiocromic film, TLD, OSL and 'Paracas Phantom' by dosimetric intercomparation in stereotactic radiosurgery

    International Nuclear Information System (INIS)

    Paucar Jauregui, R.; Condori Marcos, P.; Vidarte Garcia, F.

    2008-01-01

    Full text: In Peru, one deals to patients with arteriovenous malformations or cerebral tumors by means of stereotactic radiosurgery, using fine photon beams of high energy of 6 MeV, generated by a linear accelerator Varian 2100 Clinac CD of the Complejo Hospitalario San Pablo in Lima, Peru. In this work we describes the 'Dosimetric Intercomparation System of the Quality Assurance Program in Stereotactic Radiosurgery of the Complejo Hospitalario San Pablo (DIS)'. The DIS allows to guarantee application of the doses with high accuracy. It shows the good performance of the Local DIS's components: dosimetry of radiocromics films, dosimetry termoluminiscent (TLD), dosimetry of optically stimulated luminescence (OSL) and an anthropomorphic phantom of head constructed locally, denominated 'Paracas Phantom'. Also, in the International DIS practiced with The University of Texas Md Anderson Cancer Center, stands out results within the ranges: a) Dose to the center of the target (RDS/Institution): 0,95-1,05; b) Treated volumen (Measured/Institution): 0,75 - 1,05; c) Ratio of measure treated volume to target volume: 1,00 - 2,00; and d) Minimum dose to target (Minimum dose/Prescription dose): >0,90. It concludes that the DIS is important for the good decision making on the radiological safety of the patients dealt with stereotactic radiosurgery. (author)

  15. 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...

  16. The phantom limb in dreams.

    Science.gov (United States)

    Brugger, Peter

    2008-12-01

    Mulder and colleagues [Mulder, T., Hochstenbach, J., Dijkstra, P. U., Geertzen, J. H. B. (2008). Born to adapt, but not in your dreams. Consciousness and Cognition, 17, 1266-1271.] report that a majority of amputees continue to experience a normally-limbed body during their night dreams. They interprete this observation as a failure of the body schema to adapt to the new body shape. The present note does not question this interpretation, but points to the already existing literature on the phenomenology of the phantom limb in dreams. A summary of published investigations is complemented by a note on phantom phenomena in the dreams of paraplegic patients and persons born without a limb. Integration of the available data allows the recommendation for prospective studies to consider dream content in more detail. For instance, "adaptation" to the loss of a limb can also manifest itself by seeing oneself surrounded by amputees. Such projective types of anosognosia ("transitivism") in nocturnal dreams should also be experimentally induced in normally-limbed individuals, and some relevant techniques are mentioned.

  17. 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

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

    NARCIS (Netherlands)

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

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

  19. Mechanical design and performance specifications of anthropomorphic prosthetic hands: a review.

    Science.gov (United States)

    Belter, Joseph T; Segil, Jacob L; Dollar, Aaron M; Weir, Richard F

    2013-01-01

    In this article, we set forth a detailed analysis of the mechanical characteristics of anthropomorphic prosthetic hands. We report on an empirical study concerning the performance of several commercially available myoelectric prosthetic hands, including the Vincent, iLimb, iLimb Pulse, Bebionic, Bebionic v2, and Michelangelo hands. We investigated the finger design and kinematics, mechanical joint coupling, and actuation methods of these commercial prosthetic hands. The empirical findings are supplemented with a compilation of published data on both commercial and prototype research prosthetic hands. We discuss numerous mechanical design parameters by referencing examples in the literature. Crucial design trade-offs are highlighted, including number of actuators and hand complexity, hand weight, and grasp force. Finally, we offer a set of rules of thumb regarding the mechanical design of anthropomorphic prosthetic hands.

  20. Performance evaluation of iterative reconstruction algorithms for achieving CT radiation dose reduction - a phantom study.

    Science.gov (United States)

    Dodge, Cristina T; Tamm, Eric P; Cody, Dianna D; Liu, Xinming; Jensen, Corey T; Wei, Wei; Kundra, Vikas; Rong, X John

    2016-03-08

    The purpose of this study was to characterize image quality and dose performance with GE CT iterative reconstruction techniques, adaptive statistical iterative recontruction (ASiR), and model-based iterative reconstruction (MBIR), over a range of typical to low-dose intervals using the Catphan 600 and the anthropomorphic Kyoto Kagaku abdomen phantoms. The scope of the project was to quantitatively describe the advantages and limitations of these approaches. The Catphan 600 phantom, supplemented with a fat-equivalent oval ring, was scanned using a GE Discovery HD750 scanner at 120 kVp, 0.8 s rotation time, and pitch factors of 0.516, 0.984, and 1.375. The mA was selected for each pitch factor to achieve CTDIvol values of 24, 18, 12, 6, 3, 2, and 1 mGy. Images were reconstructed at 2.5 mm thickness with filtered back-projection (FBP); 20%, 40%, and 70% ASiR; and MBIR. The potential for dose reduction and low-contrast detectability were evaluated from noise and contrast-to-noise ratio (CNR) measurements in the CTP 404 module of the Catphan. Hounsfield units (HUs) of several materials were evaluated from the cylinder inserts in the CTP 404 module, and the modulation transfer function (MTF) was calculated from the air insert. The results were con-firmed in the anthropomorphic Kyoto Kagaku abdomen phantom at 6, 3, 2, and 1mGy. MBIR reduced noise levels five-fold and increased CNR by a factor of five compared to FBP below 6mGy CTDIvol, resulting in a substantial improvement in image quality. Compared to ASiR and FBP, HU in images reconstructed with MBIR were consistently lower, and this discrepancy was reversed by higher pitch factors in some materials. MBIR improved the conspicuity of the high-contrast spatial resolution bar pattern, and MTF quantification confirmed the superior spatial resolution performance of MBIR versus FBP and ASiR at higher dose levels. While ASiR and FBP were relatively insensitive to changes in dose and pitch, the spatial resolution for MBIR

  1. Anthropomorphic Interfaces on Automation Trust, Dependence, and Performance inYounger and Older Adults

    Science.gov (United States)

    2015-10-26

    and Human Interactive Communication, Vol., IXX, 55-60 Greenwald, A. G., & Banaji, M. R. (1995). Implicit social cognition: Attitudes, self - esteem , and...1995. “Implicit Social Cognition: Attitudes, Self - esteem , and Stereotypes.” Psychological Review 102 (1): 4–27. Hayes, C. C., and C. A. Miller. 2011...level Analysis of the Effects of Age and Gender Stereotypes on Trust in Anthropomorphic Technology by Younger and Older Adults. Ergonomics. • Rovira

  2. Adaptation and validation of a commercial head phantom for cranial radiosurgery dosimetry end-to-end audit.

    Science.gov (United States)

    Dimitriadis, Alexis; Palmer, Antony L; Thomas, Russell A S; Nisbet, Andrew; Clark, Catharine H

    2017-06-01

    To adapt and validate an anthropomorphic head phantom for use in a cranial radiosurgery audit. Two bespoke inserts were produced for the phantom: one for providing the target and organ at risk for delineation and the other for performing dose measurements. The inserts were tested to assess their positional accuracy. A basic treatment plan dose verification with an ionization chamber was performed to establish a baseline accuracy for the phantom and beam model. The phantom and inserts were then used to perform dose verification measurements of a radiosurgery plan. The dose was measured with alanine pellets, EBT extended dose film and a plastic scintillation detector (PSD). Both inserts showed reproducible positioning (±0.5 mm) and good positional agreement between them (±0.6 mm). The basic treatment plan measurements showed agreement to the treatment planning system (TPS) within 0.5%. Repeated film measurements showed consistent gamma passing rates with good agreement to the TPS. For 2%-2 mm global gamma, the mean passing rate was 96.7% and the variation in passing rates did not exceed 2.1%. The alanine pellets and PSD showed good agreement with the TPS (-0.1% and 0.3% dose difference in the target) and good agreement with each other (within 1%). The adaptations to the phantom showed acceptable accuracies. The presence of alanine and PSD do not affect film measurements significantly, enabling simultaneous measurements by all three detectors. Advances in knowledge: A novel method for thorough end-to-end test of radiosurgery, with capability to incorporate all steps of the clinical pathway in a time-efficient and reproducible manner, suitable for a national audit.

  3. Magnetic susceptibility mapping of the human thorax using a SQUID biomagnetometer.

    Science.gov (United States)

    Davies, S C; Ni, C; Fardy, J; Rassi, D

    1994-01-01

    Biomagnetism is essentially the study of the weak magnetic fields generated by biological organisms, in particular the human body. The human thorax is composed of a variety of tissues and organs of slightly different magnetic susceptibility. In an applied magnetic field (of the order of milliTeslas) these small differences in susceptibility lead to measurable field variations (of the order of nanoTeslas) at the body surface which may be of diagnostic value. Physiological processes such as cardiac activity, cardiac output, blood flow and respiratory related lung volume changes also contribute to the observed signal. In this study susceptibility 'maps' were obtained by measuring the magnetic field at several hundred points over the thorax. Results indicate that magnetic susceptibility mapping produces low-resolution images of internal body structures from which is should be possible to detect pathologies that cause alterations in tissue susceptibility.

  4. Diagnosis of the thorax in the intensive-care ward: Digital radiography

    International Nuclear Information System (INIS)

    Witte, G.; Krug, B.

    1989-01-01

    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.) [de

  5. Radiation dose from volumetric helical perfusion CT of the thorax, abdomen or pelvis

    International Nuclear Information System (INIS)

    Goh, Vicky; Dattani, Minaxi; Tam, Emily; Patel, Shilpan; Juttla, Jaspal; Simcock, Ian; Stirling, James; Farwell, Joseph; Shekhdar, Jane; Aird, Edwin; Mandeville, Henry; Hoskin, P.

    2011-01-01

    To evaluate the radiation doses delivered during volumetric helical perfusion CT of the thorax, abdomen or pelvis. The dose-length product (DLP) and CT dose index (CTDIvol) were recorded and effective dose (E) determined for patients undergoing CT (4D adaptive spiral) for tumour evaluation. Image noise and contrast to noise (CNR) at peak enhancement were also assessed for quality. Forty two consecutive examinations were included: thorax (16), abdomen (10), pelvis (16). Z-axis coverage ranged from 11.4 to 15.7 cm. Mean DLP was 1288.8 mGy.cm (range: 648 to 2456 mGy.cm). Mean CTDIvol was 96.2 mGy (range: 32.3 to 169.4 mGy). Mean effective dose was 19.6 mSv (range: 12.3 mSv to 36.7 mSv). In comparison mean DLP and effective dose was 885.2 mGy.cm (range: 504 to 1633 mGy.cm) and 13.3 mSV (range: 7.8 to 24.5 mSv) respectively for the standard staging CT thorax, abdomen and pelvis. Mean tumour CNR at peak enhancement was 1.87. The radiation dose imposed by perfusion CT was on average 1.5 times that of a CT thorax, abdomen and pelvis. The dose is not insubstantial, and must be balanced by the potential clinical utility of additional physiologic data. Further efforts towards dose reduction should be encouraged. (orig.)

  6. Differential growth and development of the upper and lower human thorax.

    Science.gov (United States)

    Bastir, Markus; García Martínez, Daniel; Recheis, Wolfgang; Barash, Alon; Coquerelle, Michael; Rios, Luis; Peña-Melián, Angel; García Río, Francisco; O'Higgins, Paul

    2013-01-01

    The difficulties in quantifying the 3D form and spatial relationships of the skeletal components of the ribcage present a barrier to studies of the growth of the thoracic skeleton. Thus, most studies to date have relied on traditional measurements such as distances and indices from single or few ribs. It is currently known that adult-like thoracic shape is achieved early, by the end of the second postnatal year, with the circular cross-section of the newborn thorax transforming into the ovoid shape of adults; and that the ribs become inclined such that their anterior borders come to lie inferior to their posterior. Here we present a study that revisits growth changes using geometric morphometrics applied to extensive landmark data taken from the ribcage. We digitized 402 (semi) landmarks on 3D reconstructions to assess growth changes in 27 computed tomography-scanned modern humans representing newborns to adults of both sexes. Our analyses show a curved ontogenetic trajectory, resulting from different ontogenetic growth allometries of upper and lower thoracic units. Adult thoracic morphology is achieved later than predicted, by diverse modifications in different anatomical regions during different ontogenetic stages. Besides a marked increase in antero-posterior dimensions, there is an increase in medio-lateral dimensions of the upper thorax, relative to the lower thorax. This transforms the pyramidal infant thorax into the barrel-shaped one of adults. Rib descent is produced by complex changes in 3D curvature. Developmental differences between upper and lower thoracic regions relate to differential timings and rates of maturation of the respiratory and digestive systems, the spine and the locomotor system. Our findings are relevant to understanding how changes in the relative rates of growth of these systems and structures impacted on the development and evolution of modern human body shape.

  7. A Case of Bezolds Abscess with an Unusual Extension to the Upper Thorax

    Directory of Open Access Journals (Sweden)

    Reza Javad Rashid

    2013-04-01

    Full Text Available The Bezold%u2019s abscess is an abscess in deep cervical spaces that is considered as a complication of otomastoiditis. Antibiotics have produced an overall decline in the frequency of complications of otitis media relative to the pre-antibiotic era. Here we report a 23 year old male with Bezold%u2019s abscess with unusual extension to upper thorax.

  8. Comparison of two respiration monitoring systems for 4D imaging with a Siemens CT using a new dynamic breathing phantom.

    Science.gov (United States)

    Vásquez, A C; Runz, A; Echner, G; Sroka-Perez, G; Karger, C P

    2012-05-07

    Four-dimensional computed tomography (4D-CT) requires breathing information from the patient, and for this, several systems are available. Testing of these systems, under realistic conditions, requires a phantom with a moving target and an expandable outer contour. An anthropomorphic phantom was developed to simulate patient breathing as well as lung tumor motion. Using the phantom, an optical camera system (GateCT) and a pressure sensor (AZ-733V) were simultaneously operated, and 4D-CTs were reconstructed with a Siemens CT using the provided local-amplitude-based sorting algorithm. The comparison of the tumor trajectories of both systems revealed discrepancies up to 9.7 mm. Breathing signal differences, such as baseline drift, temporal resolution and noise level were shown not to be the reason for this. Instead, the variability of the sampling interval and the accuracy of the sampling rate value written on the header of the GateCT-signal file were identified as the cause. Interpolation to regular sampling intervals and correction of the sampling rate to the actual value removed the observed discrepancies. Consistently, the introduction of sampling interval variability and inaccurate sampling rate values into the header of the AZ-733V file distorted the tumor trajectory for this system. These results underline the importance of testing new equipment thoroughly, especially if components of different manufacturers are combined.

  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. Dual-axis rotational coronary angiography can reduce peak skin dose and scattered dose: a phantom study.

    Science.gov (United States)

    Liu, Huiliang; Jin, Zhigeng; Deng, Yunpeng; Jing, Limin

    2014-07-08

    The purpose of this study was to evaluate peak skin dose received by the patient and scattered dose to the operator during dual-axis rotational coronary angiography (DARCA), and to compare with those of standard coronary angiography (SA). An anthropomorphic phantom was used to simulate a patient undergoing diagnostic coronary angiography. Cine imaging was applied on the phantom for 2 s, 3 s, and 5 s in SA projections to mimic clinical situations with normal vessels, and uncomplicated and complicated coronary lesions. DARCA was performed in two curved trajectories around the phantom. During both SA and DARCA, peak skin dose was measured with thermoluminescent dosimeter arrays and scattered dose with a dosimeter at predefined height (approximately at the level of left eye) at the operator's location. Compared to SA, DARCA was found lower in both peak skin dose (range: 44%-82%, p < 0.001) and scattered dose (range: 40%-70%, p < 0.001). The maximal reductions were observed in the set mimicking complicated lesion examinations (82% reduction for peak skin dose, p < 0.001; 70% reduction for scattered dose, p < 0.001). DARCA reduces both peak skin dose and scattered dose in comparison to SA. The benefi t of radiation dose reduction could be especially signifi cant in complicated lesion examinations due to large reduction in X-ray exposure time. The use of DARCA could, therefore, be recommended in clinical practice to minimize radiation dose.

  11. Effect of Cardiac Phases and Conductivity Inhomogeneities of the Thorax Models on ECG Lead Selection and Reconstruction

    National Research Council Canada - National Science Library

    Takano, Noriyuki

    2001-01-01

    ECG lead selection and reconstruction were investigated in the present study using ECG source-to-measurement transfer matrices computed in inhomogeneous and homogeneous conductor thorax-heart models...

  12. The Japanese adult, child and infant phantoms

    International Nuclear Information System (INIS)

    Cristy, Mark; Egbert, Stephen D.

    1987-01-01

    The mathematical phantom for adult Japanese atomic-bomb survivors is a modification of the 57-kg ORNL (Oak Ridge National Laboratory) phantom for Western 15-year-old males and adult females. For younger Japanese survivors mathematical phantoms were similarly modified from the 18 and 9 kg ORNL phantoms for Western 5- and 1-year-olds, respectively. To make the phantom correspond more closely with dimensions and organ sizes recommended for Japanese adults by Maruyama and coworkers (cf E184), changes were made in the size of the lungs, the pancreas, the thyroid, and the testes and in the length of the legs. Also, the head-and-neck region was modified to improve the dose estimates for the thyroid from external radiation, after the ideas of Nagarajan et al. The arms were separated from the trunk to represent more accurately the shielding by the phantom in external exposures. Furthermore, provisions were made to provide a phantom in a kneeling posture. The elemental composition of the tissues was changed to that given by Kerr. The resulting phantom is slightly smaller in mass (55 kg). Details of these changes are given

  13. Segmentasi Paru-Paru pada Citra X-Ray Thorax Menggunakan Distance Regularized Levelset Evolution (DRLSE

    Directory of Open Access Journals (Sweden)

    M Amin Hariyadi

    2017-03-01

    Full Text Available -- Lung is one in control in the circulatory system of air (oxygen in the human body, so the detection of disorders of the human respiratory urgently needed to detect any disturbance in the lungs used X-ray beam, from the results of x-ray image of the thorax contained information used to analyze and determine the shape of an object from the lungs, in order to obtain such information, a process of segmentation. In this study used methods Distance regularized Levelset Evolution (DLRSE, this method region based models which is an improvement of edge-based models. The purpose of this study to implement segmentation methods DRLSE the lungs of the results of x-ray image of the thorax. The trial results with the system DLRSE method performed on the 20 data from X-ray image of the thorax obtained an average result accuracy of 87.90%, a sensitivity of 76.27% and a specificity of 93.98%.

  14. A Scott bench with ergonomic thorax stabilisation pad improves body posture during preacher arm curl exercise.

    Science.gov (United States)

    Biscarini, Andrea; Benvenuti, Paolo; Busti, Daniele; Zanuso, Silvano

    2016-05-01

    We assessed whether the use of an ergonomic thorax stabilisation pad, during the preacher arm curl exercise, could significantly reduce the excessive shoulder protraction and thoracic kyphosis induced by the standard flat pad built into the existing preacher arm curl equipment. A 3D motion capture system and inclinometers were used to measure shoulder protraction and thoracic kyphosis in 15 subjects performing preacher arm curl with a plate-loaded machine provided with the standard flat pad. The same measures were repeated after replacing the flat pad with a new ergonomic pad, specifically designed to accommodate the thorax profile and improve body posture. Pad replacement significantly (p ergonomic pad may potentially allow a more effective training, prevent musculoskeletal discomfort and reduce the risk of injury. Practitioner summary: We have designed an ergonomic thorax stabilisation pad for the preacher arm curl exercise. The new ergonomic pad improves the poor posture conditions induced by the standard flat pad and may potentially allow a more effective training, prevent musculoskeletal discomfort, improve the breathing function and reduce the risk of injury.

  15. Problems arising in differential diagnosis in the chest X-ray in patients with small sagittal diameter of the thorax

    International Nuclear Information System (INIS)

    Huebsch, P.; Stiglbauer, R.; Barton, P.; Frank, H.

    1989-01-01

    In patients with a small sagittal diameter of the thorax often carcia murmurs are heard. Since the p.a. chest X-ray in such cases often shows an enlarged heart shadow, problems arise in the interpretation of the films. In this paper, the typical appearance of the heart shadow in patients with small sagittal diameter of the thorax is described and the differential diagnosis is discussed. Echocardiography is the ideal additional diagnostic method, when problems in differential diagnosis occur. (orig.) [de

  16. A phantom for quality control in mammography

    International Nuclear Information System (INIS)

    Gambaccini, M.; Rimondi, O.; Marziani, M.; Toti, A.

    1989-01-01

    A phantom for evaluating image quality in mammography has been designed and will be used in the Italian national programme ''Dose and Quality in Mammography''. The characteristics of the phantom are (a) about the same X-ray transmission as a 5 cm 50% fat and 50% water breast for energies between 15 and 50 keV and (b) optimum energies for imaging of the test objects (included in the phantom) in very close agreement with the optimum energies for imaging of calcifications and tumours in a 5 cm 50% fat and 50% water breast. An experimental comparison between the prototype and some commercial phantoms was carried out. Measurements are in progress to test the phantom's ability to evaluate the performances of mammographic systems quantitatively. (author)

  17. Bismuth Infusion of ABS Enables Additive Manufacturing of Complex Radiological Phantoms and Shielding Equipment

    Directory of Open Access Journals (Sweden)

    Justin Ceh

    2017-02-01

    Full Text Available Radiopacity is a critical property of materials that are used for a range of radiological applications, including the development of phantom devices that emulate the radiodensity of native tissues and the production of protective equipment for personnel handling radioactive materials. Three-dimensional (3D printing is a fabrication platform that is well suited to creating complex anatomical replicas or custom labware to accomplish these radiological purposes. We created and tested multiple ABS (Acrylonitrile butadiene styrene filaments infused with varied concentrations of bismuth (1.2–2.7 g/cm3, a radiopaque metal that is compatible with plastic infusion, to address the poor gamma radiation attenuation of many mainstream 3D printing materials. X-ray computed tomography (CT experiments of these filaments indicated that a density of 1.2 g/cm3 of bismuth-infused ABS emulates bone radiopacity during X-ray CT imaging on preclinical and clinical scanners. ABS-bismuth filaments along with ABS were 3D printed to create an embedded human nasocranial anatomical phantom that mimicked radiological properties of native bone and soft tissue. Increasing the bismuth content in the filaments to 2.7 g/cm3 created a stable material that could attenuate 50% of 99mTechnetium gamma emission when printed with a 2.0 mm wall thickness. A shielded test tube rack was printed to attenuate source radiation as a protective measure for lab personnel. We demonstrated the utility of novel filaments to serve multiple radiological purposes, including the creation of anthropomorphic phantoms and safety labware, by tuning the level of radiation attenuation through material customization.

  18. 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.

  19. A phantom model demonstration of tomotherapy dose painting delivery, including managed respiratory motion without motion management

    International Nuclear Information System (INIS)

    Kissick, Michael W; Mo Xiaohu; McCall, Keisha C; Mackie, Thomas R; Schubert, Leah K; Westerly, David C

    2010-01-01

    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.

  20. Poster — Thur Eve — 71: A 4D Multimodal Lung Phantom for Regmentation Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Markel, D [McGill University, Physics, Montreal QC (Canada); Levesque, I R [McGill University, Oncology, Montreal QC (Canada); Research Institute of the McGill University Health Centre, Montreal, QC (Canada); El Naqa, I [McGill University, Physics, Montreal QC (Canada); McGill University, Oncology, Montreal QC (Canada)

    2014-08-15

    Segmentation and registration of medical imaging data are two processes that can be integrated (a process termed regmentation) to iteratively reinforce each other, potentially improving efficiency and overall accuracy. A significant challenge is presented when attempting to validate the joint process particularly with regards to minimizing geometric uncertainties associated with the ground truth while maintaining anatomical realism. This work demonstrates a 4D MRI, PET, and CT compatible tissue phantom with a known ground truth for evaluating registration and segmentation accuracy. The phantom consists of a preserved swine lung connected to an air pump via a PVC tube for inflation. Mock tumors were constructed from sea sponges contained within two vacuum-sealed compartments with catheters running into each one for injection of radiotracer solution. The phantom was scanned using a GE Discovery-ST PET/CT scanner and a 0.23T Phillips MRI, and resulted in anatomically realistic images. A bifurcation tracking algorithm was implemented to provide a ground truth for evaluating registration accuracy. This algorithm was validated using known deformations of up to 7.8 cm using a separate CT scan of a human thorax. Using the known deformation vectors to compare against, 76 bifurcation points were selected. The tracking accuracy was found to have maximum mean errors of −0.94, 0.79 and −0.57 voxels in the left-right, anterior-posterior and inferior-superior directions, respectively. A pneumatic control system is under development to match the respiratory profile of the lungs to a breathing trace from an individual patient.

  1. Poster — Thur Eve — 71: A 4D Multimodal Lung Phantom for Regmentation Evaluation

    International Nuclear Information System (INIS)

    Markel, D; Levesque, I R; El Naqa, I

    2014-01-01

    Segmentation and registration of medical imaging data are two processes that can be integrated (a process termed regmentation) to iteratively reinforce each other, potentially improving efficiency and overall accuracy. A significant challenge is presented when attempting to validate the joint process particularly with regards to minimizing geometric uncertainties associated with the ground truth while maintaining anatomical realism. This work demonstrates a 4D MRI, PET, and CT compatible tissue phantom with a known ground truth for evaluating registration and segmentation accuracy. The phantom consists of a preserved swine lung connected to an air pump via a PVC tube for inflation. Mock tumors were constructed from sea sponges contained within two vacuum-sealed compartments with catheters running into each one for injection of radiotracer solution. The phantom was scanned using a GE Discovery-ST PET/CT scanner and a 0.23T Phillips MRI, and resulted in anatomically realistic images. A bifurcation tracking algorithm was implemented to provide a ground truth for evaluating registration accuracy. This algorithm was validated using known deformations of up to 7.8 cm using a separate CT scan of a human thorax. Using the known deformation vectors to compare against, 76 bifurcation points were selected. The tracking accuracy was found to have maximum mean errors of −0.94, 0.79 and −0.57 voxels in the left-right, anterior-posterior and inferior-superior directions, respectively. A pneumatic control system is under development to match the respiratory profile of the lungs to a breathing trace from an individual patient

  2. Biomimetic phantom for cardiac diffusion MRI.

    Science.gov (United States)

    Teh, Irvin; Zhou, Feng-Lei; Hubbard Cristinacce, Penny L; Parker, Geoffrey J M; Schneider, Jürgen E

    2016-03-01

    Diffusion magnetic resonance imaging (MRI) is increasingly used to characterize cardiac tissue microstructure, necessitating the use of physiologically relevant phantoms for methods development. Existing phantoms are generally simplistic and mostly simulate diffusion in the brain. Thus, there is a need for phantoms mimicking diffusion in cardiac tissue. A biomimetic phantom composed of hollow microfibers generated using co-electrospinning was developed to mimic myocardial diffusion properties and fiber and sheet orientations. Diffusion tensor imaging was carried out at monthly intervals over 4 months at 9.4T. 3D fiber tracking was performed using the phantom and compared with fiber tracking in an ex vivo rat heart. The mean apparent diffusion coefficient and fractional anisotropy of the phantom remained stable over the 4-month period, with mean values of 7.53 ± 0.16 × 10(-4) mm(2) /s and 0.388 ± 0.007, respectively. Fiber tracking of the 1st and 3rd eigenvectors generated analogous results to the fiber and sheet-normal direction respectively, found in the left ventricular myocardium. A biomimetic phantom simulating diffusion in the heart was designed and built. This could aid development and validation of novel diffusion MRI methods for investigating cardiac microstructure, decrease the number of animals and patients needed for methods development, and improve quality control in longitudinal and multicenter cardiac diffusion MRI studies. © 2015 The Authors Journal of Magnetic Resonance Imaging published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.

  3. Direct Effective Dose Calculations in Pediatric Fluoroscopy-Guided Abdominal Interventions with Rando-Alderson Phantoms – Optimization of Preset Parameter Settings

    Science.gov (United States)

    Wildgruber, Moritz; Müller-Wille, René; Goessmann, Holger; Uller, Wibke; Wohlgemuth, Walter A.

    2016-01-01

    Objective The aim of the study was to calculate the effective dose during fluoroscopy-guided pediatric interventional procedures of the liver in a phantom model before and after adjustment of preset parameters. Methods Organ doses were measured in three anthropomorphic Rando-Alderson phantoms representing children at various age and body weight (newborn 3.5kg, toddler 10kg, child 19kg). Collimation was performed focusing on the upper abdomen representing mock interventional radiology procedures such as percutaneous transhepatic cholangiography and drainage placement (PTCD). Fluoroscopy and digital subtraction angiography (DSA) acquisitions were performed in a posterior-anterior geometry using a state of the art flat-panel detector. Effective dose was directly measured from multiple incorporated thermoluminescent dosimeters (TLDs) using two different parameter settings. Results Effective dose values for each pediatric phantom were below 0.1mSv per minute fluoroscopy, and below 1mSv for a 1 minute DSA acquisition with a frame rate of 2 f/s. Lowering the values for the detector entrance dose enabled a reduction of the applied effective dose from 12 to 27% for fluoroscopy and 22 to 63% for DSA acquisitions. Similarly, organ doses of radiosensitive organs could be reduced by over 50%, especially when close to the primary x-ray beam. Conclusion Modification of preset parameter settings enabled to decrease the effective dose for pediatric interventional procedures, as determined by effective dose calculations using dedicated pediatric Rando-Alderson phantoms. PMID:27556584

  4. Charged black holes in phantom cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Jamil, Mubasher; Qadir, Asghar; Rashid, Muneer Ahmad [National University of Sciences and Technology, Center for Advanced Mathematics and Physics, Rawalpindi (Pakistan)

    2008-11-15

    In the classical relativistic regime, the accretion of phantom-like dark energy onto a stationary black hole reduces the mass of the black hole. We have investigated the accretion of phantom energy onto a stationary charged black hole and have determined the condition under which this accretion is possible. This condition restricts the mass-to-charge ratio in a narrow range. This condition also challenges the validity of the cosmic-censorship conjecture since a naked singularity is eventually produced due to accretion of phantom energy onto black hole. (orig.)

  5. Basic studies of radiation image diagnosis in veterinary medicine, 1: Comparison of the resolution of computed tomography, scanography and conventional radiography in an equine thoracic phantom

    International Nuclear Information System (INIS)

    Shida, T.; Suganuma, T.; Hashizume, T.

    1984-01-01

    In radiography of the thorax and abdomen of a large animal, the extreme thickness of the body causes a large amount of scattered radiation, which makes it difficult to obtain sharp images. The image resolutions of radiographs obtained by applying conventional radiography, scanography and computed tomography [CT] on an equine thoracic phantom were compared. Tubes of various inside diameters, used to simulate the pulmonary vessels were placed in an equine thoracic phantom and radiographed by CT, scanography and conventional radiography so as to compare the various degrees of resolution of the images of the tubes obtained by these methods. CT and scanography both gave a higher resolution index than conventional radiography, and both provided recognizable images of tubes < 2 mm in diameter, which conventional radiography failed to do. Scanography and CT can be used to obtain high-quality images of the thorax and abdomen of large animals. The image quality was compared using the resolution index (RI). The RI would be a wholly practical and comprehensive index for resolution because it includes 3 factors, contrast, sharpness and magnification, and yet is easy to calculate

  6. 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

    2016-05-03

    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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Evaluation of absorbed and effective doses to patients from radiopharmaceuticals using the ICRP 110 reference computational phantoms and ICRP 103 formulation

    International Nuclear Information System (INIS)

    Hadid, L.; Gardumi, A.; Desbree, A.

    2013-01-01

    radiopharmaceuticals, where the differences can reach 60 % higher than the published values. This study analyses the first set of absorbed and effective doses with the new ICRP male and female reference computational phantoms for different radiopharmaceuticals. It highlights the importance of taking into account the electron transport and the realism of the shape and inter-organ distances of the anthropomorphic model used. (authors)

  8. Depth Dose Distribution Study within a Phantom Torso after Irradiation with a Simulated Solar Particle Event at NSRL

    Science.gov (United States)

    Berger, Thomas; Matthiae, Daniel; Koerner, Christine; George, Kerry; Rhone, Jordan; Cucinotta, Francis; Reitz, Guenther

    2010-01-01

    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 initial focus of the present experiment is to correlate biological results with physical dosimetry measurements in the phantom torso. Further on, the results of the passive dosimetry within the anthropomorphic phantoms represent the best tool to generate reliable data to benchmark computational radiation transport models in a radiation field of interest. The presentation will give first results of the physical dose distribution, the comparison with GEANT4 computer simulations based on a Voxel model of the phantom, and a comparison with the data from the chromosome aberration study.

  9. Wormholes supported by phantom energy

    International Nuclear Information System (INIS)

    Gonzalez, J. A.; Guzman, F. S.; Montelongo-Garcia, N.; Zannias, T.

    2009-01-01

    By a combination of analytical and numerical techniques, we demonstrate the existence of spherical, asymptotically flat traversable wormholes supported by exotic matter whose stress tensor relative to the orthonormal frame of Killing observers takes the form of a perfect fluid possessing anisotropic pressures and subject to linear equations of state: τ=λρc 2 , P=μρc 2 . We show that there exists a four parameter family of asymptotically flat spherical wormholes parametrized by the area of the throat A(0), the gradient Λ(0) of the red shift factor evaluated on the throat as well as the values of (λ,μ). The latter are subject to restrictions: λ>1 and 2μ>λ or λ<0 and 2μ<-|λ|. For particular values of (λ,μ), the stress tensor may be interpreted as representing a phantom configuration, while for other values represents exotic matter. All solutions have the property that the two asymptotically flat ends possess finite Arnowitt-Deser-Misner mass.

  10. Tessier 3 Cleft in a Pre-Hispanic Anthropomorphic Figurine in El Salvador, Central America.

    Science.gov (United States)

    Aleman, Ramon Manuel; Martinez, Maria Guadalupe

    2017-03-01

    In 1976, Paul Tessier provided a numerical classification system for rare facial clefts, numbered from 0 to 14. The Tessier 3 cleft is a rare facial cleft extending from the philtrum of the upper lip through the wing of the nostril, and reaches the medial canthus of the eye. The aim of this document was to describe a pre-Hispanic anthropomorphic figurine dating from the classic period (200 A.D.-900 A.D.), which has a Tessier 3 cleft. We also discuss the documented pre-Hispanic beliefs about facial clefts.

  11. Phantom cosmology without Big Rip singularity

    Energy Technology Data Exchange (ETDEWEB)

    Astashenok, Artyom V. [Baltic Federal University of I. Kant, Department of Theoretical Physics, 236041, 14, Nevsky st., Kaliningrad (Russian Federation); Nojiri, Shin' ichi, E-mail: nojiri@phys.nagoya-u.ac.jp [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan); Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, Nagoya 464-8602 (Japan); Odintsov, Sergei D. [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan); Institucio Catalana de Recerca i Estudis Avancats - ICREA and Institut de Ciencies de l' Espai (IEEC-CSIC), Campus UAB, Facultat de Ciencies, Torre C5-Par-2a pl, E-08193 Bellaterra (Barcelona) (Spain); Tomsk State Pedagogical University, Tomsk (Russian Federation); Yurov, Artyom V. [Baltic Federal University of I. Kant, Department of Theoretical Physics, 236041, 14, Nevsky st., Kaliningrad (Russian Federation)

    2012-03-23

    We construct phantom energy models with the equation of state parameter w which is less than -1, w<-1, but finite-time future singularity does not occur. Such models can be divided into two classes: (i) energy density increases with time ('phantom energy' without 'Big Rip' singularity) and (ii) energy density tends to constant value with time ('cosmological constant' with asymptotically de Sitter evolution). The disintegration of bound structure is confirmed in Little Rip cosmology. Surprisingly, we find that such disintegration (on example of Sun-Earth system) may occur even in asymptotically de Sitter phantom universe consistent with observational data. We also demonstrate that non-singular phantom models admit wormhole solutions as well as possibility of Big Trip via wormholes.

  12. 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).

  13. The influence of breathing motion on intensity modulated radiotherapy in the step-and-shoot technique: phantom measurements for irradiation of superficial target volumes

    Energy Technology Data Exchange (ETDEWEB)

    Thilmann, Christoph [Klinische Kooperationseinheit Radioonkologie des Deutschen Krebsforschungszentrums, INF 280, 69120 Heidelberg (Germany); Haering, Peter [Medizinische Physik des Deutschen Krebsforschungszentrums, INF 280, 69120 Heidelberg (Germany); Thilmann, Lennart [Klinische Kooperationseinheit Radioonkologie des Deutschen Krebsforschungszentrums, INF 280, 69120 Heidelberg (Germany); Unkelbach, Jan [Medizinische Physik des Deutschen Krebsforschungszentrums, INF 280, 69120 Heidelberg (Germany); Rhein, Bernhard [Medizinische Physik des Deutschen Krebsforschungszentrums, INF 280, 69120 Heidelberg (Germany); Nill, Simeon [Medizinische Physik des Deutschen Krebsforschungszentrums, INF 280, 69120 Heidelberg (Germany); Huber, Peter [Klinische Kooperationseinheit Radioonkologie des Deutschen Krebsforschungszentrums, INF 280, 69120 Heidelberg (Germany); Janisch, Elisabeth [Medizinische Physik des Deutschen Krebsforschungszentrums, INF 280, 69120 Heidelberg (Germany); Thieke, Christian [Klinische Kooperationseinheit Radioonkologie des Deutschen Krebsforschungszentrums, INF 280, 69120 Heidelberg (Germany); Debus, Juergen [Klinische Radiologie des Universitaetsklinikums Heidelberg, INF 400, 69120 Heidelberg (Germany)

    2006-03-21

    For intensity modulated radiotherapy (IMRT) of deep-seated tumours, dosimetric variations of the original static dose profiles due to breathing motion can be primarily considered as blurring effects known from conventional radiotherapy. The purpose of this dosimetric study was to clarify whether these results are transferable to superficial targets and to quantify the additional effect of fractionation. A solid polystyrene phantom and an anthropomorphic phantom were used for film and ion chamber dose measurements. The phantoms were installed on an electric driven device and moved with a frequency of 6 or 12 cycles per minute and an amplitude of 4 mm or 10 mm. A split beam geometry of two adjacent asymmetric fields and an IMRT treatment plan with 12 fields for irradiation of the breast were investigated. For the split beam geometry the dose modifications due to unintended superposition of partial fields were reduced by fractionation and completely smoothed out after 20 fractions. IMRT applied to the moving phantom led to a more homogeneous dose distribution compared to the static phantom. The standard deviation of the target dose which is a measure of the dose homogeneity was 10.3 cGy for the static phantom and 7.7 cGy for a 10 mm amplitude. The absolute dose values, measured with ionization chambers, remained unaffected. Irradiation of superficial targets by IMRT in the step-and-shoot technique did not result in unexpected dose perturbations due to breathing motion. We conclude that regular breathing motion does not jeopardize IMRT of superficial target volumes. (note)

  14. Head phantoms for transcranial focused ultrasound.

    Science.gov (United States)

    Eames, Matthew D C; Farnum, Mercy; Khaled, Mohamad; Elias, W Jeff; Hananel, Arik; Snell, John W; Kassell, Neal F; Aubry, Jean-Francois

    2015-04-01

    In the ongoing endeavor of fine-tuning, the clinical application of transcranial MR-guided focused ultrasound (tcMRgFUS), ex-vivo studies wlkiith whole human skulls are of great use in improving the underlying technology guiding the accurate and precise thermal ablation of clinically relevant targets in the human skull. Described here are the designs, methods for fabrication, and notes on utility of three different ultrasound phantoms to be used for brain focused ultrasound research. Three different models of phantoms are developed and tested to be accurate, repeatable experimental options to provide means to further this research. The three models are a cadaver, a gel-filled skull, and a head mold containing a skull and filled with gel that mimics the brain and the skin. Each was positioned in a clinical tcMRgFUS system and sonicated at 1100 W (acoustic) for 12 s at different locations. Maximum temperature rise as measured by MR thermometry was recorded and compared against clinical data for a similar neurosurgical target. Results are presented as heating efficiency in units (°C/kW/s) for direct comparison to available clinical data. The procedure for casting thermal phantom material is presented. The utility of each phantom model is discussed in the context of various tcMRgFUS research areas. The cadaveric phantom model, gel-filled skull model, and full head phantom model had heating efficiencies of 5.3, 4.0, and 3.9 °C/(kW/s), respectively, compared to a sample clinical heating efficiency of 2.6 °C/(kW/s). In the seven research categories considered, the cadaveric phantom model was the most versatile, though less practical compared to the ex-vivo skull-based phantoms. Casting thermal phantom material was shown to be an effective way to prepare tissue-mimicking material for the phantoms presented. The phantom models presented are all useful in tcMRgFUS research, though some are better suited to a limited subset of applications depending on the researchers

  15. A CT simulator phantom for geometrical test

    International Nuclear Information System (INIS)

    Min, Chul Kee; Yi, Byong Yong; Ahn, Seung Do; Choi, Eun Kyung; Chang, Hye Sook

    2000-01-01

    To design and test the CT simulator phantom for geometrical test. The PMMA phantom was designed as a cylinder which is 20 cm in diameter and 24 cm in lengt