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    25 results match your criteria BMC Medical Physics [Journal]

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    Microwave open-ended coaxial dielectric probe: interpretation of the sensing volume re-visited.
    BMC Med Phys 2014 17;14. Epub 2014 Jun 17.
    Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH 03755, USA.
    Background: Tissue dielectric properties are specific to physiological changes and consequently have been pursued as imaging biomarkers of cancer and other pathological disorders. However, a recent study (Phys Med Biol 52:2637-2656, 2007; Phys Med Biol 52:6093-6115, 2007), which utilized open-ended dielectric probing techniques and a previously established sensing volume, reported that the dielectric property contrast may only be 10% or less between breast cancer and normal fibroglandular tissue whereas earlier data suggested ratios of 4:1 and higher may exist. Questions about the sensing volume of this probe relative to the amount of tissue interrogated raise the distinct possibility that the conclusions drawn from that study may have been over interpreted. Read More

    Diagnosis of cervical cells based on fractal and Euclidian geometrical measurements: Intrinsic Geometric Cellular Organization.
    BMC Med Phys 2014 17;14. Epub 2014 Apr 17.
    Insight Group Researcher. Universidad Militar Nueva Granada, Research Center, Clínica del Country, Cll 45sur 78I 25, Bogotá, Colombia.
    Background: Fractal geometry has been the basis for the development of a diagnosis of preneoplastic and neoplastic cells that clears up the undetermination of the atypical squamous cells of undetermined significance (ASCUS).

    Methods: Pictures of 40 cervix cytology samples diagnosed with conventional parameters were taken. A blind study was developed in which the clinic diagnosis of 10 normal cells, 10 ASCUS, 10 L-SIL and 10 H-SIL was masked. Read More

    Validity of actigraphs uniaxial and triaxial accelerometers for assessment of physical activity in adults in laboratory conditions.
    BMC Med Phys 2013 Nov 26;13(1). Epub 2013 Nov 26.
    Department of Exercise Science, California Lutheran University, 60 W, Olsen Road, #3400, Thousand Oaks, CA 91360, USA.
    Background: Few studies to date have directly compared the Actigraphs GT1M and the GT3X, it would be of tremendous value to know if these accelerometers give similar information about intensities of PA. Knowing if output is similar would have implications for cross-examination of studies. The purpose of the study was to assess the validity of the GT1M and the GT3X Actigraph accelerometers for the assessment of physical activity against oxygen consumption in laboratory conditions. Read More

    Real-time prostate motion assessment: image-guidance and the temporal dependence of intra-fraction motion.
    BMC Med Phys 2013 Sep 23;13(1). Epub 2013 Sep 23.
    Department of Radiation Medicine, Oregon Health & Science University, Portland, OR, USA.
    Background: The rapid adoption of image-guidance in prostate intensity-modulated radiotherapy (IMRT) results in longer treatment times, which may result in larger intrafraction motion, thereby negating the advantage of image-guidance. This study aims to qualify and quantify the contribution of image-guidance to the temporal dependence of intrafraction motion during prostate IMRT.

    Methods: One-hundred and forty-three patients who underwent conventional IMRT (n=67) or intensity-modulated arc therapy (IMAT/RapidArc, n=76) for localized prostate cancer were evaluated. Read More

    Predictions of CD4 lymphocytes' count in HIV patients from complete blood count.
    BMC Med Phys 2013 Sep 14;13(1). Epub 2013 Sep 14.
    Insight Group, Research Area and Special Internship "Mathematical and Physical Theories Applied to Medicine", Medicine Faculty, Universidad Militar Nueva Granada, Cr 11 No,101-80 Bogotá, Colombia.
    Background: HIV diagnosis, prognostic and treatment requires T CD4 lymphocytes' number from flow cytometry, an expensive technique often not available to people in developing countries. The aim of this work is to apply a previous developed methodology that predicts T CD4 lymphocytes' value based on total white blood cell (WBC) count and lymphocytes count applying sets theory, from information taken from the Complete Blood Count (CBC).

    Methods: Sets theory was used to classify into groups named A, B, C and D the number of leucocytes/mm3, lymphocytes/mm3, and CD4/μL3 subpopulation per flow cytometry of 800 HIV diagnosed patients. Read More

    Dose mapping sensitivity to deformable registration uncertainties in fractionated radiotherapy - applied to prostate proton treatments.
    BMC Med Phys 2013 Jun 14;13(1). Epub 2013 Jun 14.
    Department of Radiology, Oncology and Radiation Sciences, Uppsala University, Uppsala, Sweden.
    Background: Calculation of accumulated dose in fractionated radiotherapy based on spatial mapping of the dose points generally requires deformable image registration (DIR). The accuracy of the accumulated dose thus depends heavily on the DIR quality. This motivates investigations of how the registration uncertainty influences dose planning objectives and treatment outcome predictions. Read More

    The 2D Hotelling filter - a quantitative noise-reducing principal-component filter for dynamic PET data, with applications in patient dose reduction.
    BMC Med Phys 2013 Apr 10;13. Epub 2013 Apr 10.
    Department of Radiation Sciences, Radiation Physics, Umeå University, Umeå, Sweden.
    Background: In this paper we apply the principal-component analysis filter (Hotelling filter) to reduce noise from dynamic positron-emission tomography (PET) patient data, for a number of different radio-tracer molecules. We furthermore show how preprocessing images with this filter improves parametric images created from such dynamic sequence.We use zero-mean unit variance normalization, prior to performing a Hotelling filter on the slices of a dynamic time-series. Read More

    Multiscale forward electromagnetic model of uterine contractions during pregnancy.
    BMC Med Phys 2012 Nov 5;12. Epub 2012 Nov 5.
    Department of Electrical and Systems Engineering, Washington University, Saint Louis, Missouri 63130, USA.
    Background: Analyzing and monitoring uterine contractions during pregnancy is relevant to the field of reproductive health assessment. Its clinical importance is grounded in the need to reliably predict the onset of labor at term and pre-term. Preterm births can cause health problems or even be fatal for the fetus. Read More

    The study of radiosensitivity in left handed compared to right handed healthy women.
    BMC Med Phys 2012 Aug 24;12. Epub 2012 Aug 24.
    Medical Physics, Cellular & Molecular Biology Research Center, Babol University of Medical Sciences, Babol, Iran.

    Background: Radiosensitivity is an inheriting trait that mainly depends on genetic factors. it is well known in similar dose of ionizing radiation and identical biological characteristics 9-10 percent of normal population have higher radiation response. Some reports indicate that distribution of breast cancer, immune diseases including autoimmune diseases as example lupus, Myasthenia Gravies and even the rate of allergy are more frequent in left handed individuals compared to right handed individuals. Read More

    Comparison of the dosimetries of 3-dimensions Radiotherapy (3D-RT) with linear accelerator and intensity modulated radiotherapy (IMRT) with helical tomotherapy in children irradiated for neuroblastoma.
    BMC Med Phys 2012 Jun 28;12. Epub 2012 Jun 28.
    Department of Radiation Oncology, Centre de lutte contre le Cancer Paul Strauss, BP42, 3, rue de la porte de l'hôpital, BP 62, F-67065, Strasbourg, cedex, France.
    Background: Intensity modulated radiotherapy is an efficient radiotherapy technique to increase dose in target volumes and decrease irradiation dose in organs at risk. This last objective is mainly relevant in children. However, previous results suggested that IMRT could increase low dose, factor of risk for secondary radiation induced cancer. Read More

    Navigator channel adaptation to reconstruct three dimensional heart volumes from two dimensional radiotherapy planning data.
    BMC Med Phys 2012 Jan 18;12. Epub 2012 Jan 18.
    Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario, Canada.
    Background: Biologically-based models that utilize 3D radiation dosimetry data to estimate the risk of late cardiac effects could have significant utility for planning radiotherapy in young patients. A major challenge arises from having only 2D treatment planning data for patients with long-term follow-up. In this study, we evaluate the accuracy of an advanced deformable image registration (DIR) and navigator channels (NC) adaptation technique to reconstruct 3D heart volumes from 2D radiotherapy planning images for Hodgkin's Lymphoma (HL) patients. Read More

    Preclinical multimodality phantom design for quality assurance of tumor size measurement.
    BMC Med Phys 2011 Sep 30;11. Epub 2011 Sep 30.
    Department of Radiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
    Background: Evaluation of changes in tumor size from images acquired by ultrasound (US), computed tomography (CT) or magnetic resonance imaging (MRI) is a common measure of cancer chemotherapy efficacy. Tumor size measurement based on either the World Health Organization (WHO) criteria or the Response Evaluation Criteria in Solid Tumors (RECIST) is the only imaging biomarker for anti-cancer drug testing presently approved by the United States Food and Drug Administration (FDA). The aim of this paper was to design and test a quality assurance phantom with the capability of monitoring tumor size changes with multiple preclinical imaging scanners (US, CT and MRI) in order to facilitate preclinical anti-cancer drug testing. Read More

    Theoretical generalization of normal and sick coronary arteries with fractal dimensions and the arterial intrinsic mathematical harmony.
    BMC Med Phys 2010 Sep 17;10. Epub 2010 Sep 17.
    MD, Insight Group Director - Investigation Center, Clínica del Country, Professor and Director of the research area: "Mathematical and Physical Theories Applied to Medicine", Universidad Militar Nueva Granada, Cr 11 No, 101-80, Bogotá, Colombia.
    Background: Fractal geometry is employ to characterize the irregular objects and had been used in experimental and clinic applications. Starting from a previous work, here we made a theoretical research based on a geometric generalization of the experimental results, to develop a theoretical generalization of the stenotic and restenotic process, based on fractal geometry and Intrinsic Mathematical Harmony.

    Methods: Starting from all the possibilities of space occupation in box-counting space, all arterial prototypes differentiating normality and disease were obtained with a computational simulation. Read More

    Differential radio-sensitivities of human chromosomes 1 and 2 in one donor in interphase- and metaphase-spreads after 60Co gamma-irradiation.
    BMC Med Phys 2009 Jun 16;9. Epub 2009 Jun 16.
    Armed Forces Radiobiology Research Institute, Uniformed Services University of Health Sciences, 8901 Wisconsin Avenue, Bethesda, MD 20889-5603, USA.
    Background: Radiation-induced chromosome aberrations lead to a plethora of detrimental effects at cellular level. Chromosome aberrations provide broad spectrum of information ranging from probability of malignant transformation to assessment of absorbed dose. Studies mapping differences in radiation sensitivities between human chromosomes are seldom undertaken. Read More

    Prognostic implication of late gadolinium enhancement on cardiac MRI in light chain (AL) amyloidosis on long term follow up.
    BMC Med Phys 2009 May 5;9. Epub 2009 May 5.
    Cardiovascular Medicine Division, Medical College of Wisconsin, 9200 W Wisconsin Avenue, Milwaukee WI 53226, USA.
    Background: Light chain amyloidosis (AL) is a rare plasma cell dyscrasia associated with poor survival especially in the setting of heart failure. Late gadolinium enhancement (LGE) on cardiac MRI was recently found to correlate with myocardial amyloid deposition but the prognostic role is not established. The aim is to determine the prognostic significance of LGE in AL by comparing long term survival of AL patients with and without LGE. Read More

    Average arterial input function for quantitative dynamic contrast enhanced magnetic resonance imaging of neck nodal metastases.
    BMC Med Phys 2009 Apr 7;9. Epub 2009 Apr 7.
    Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
    Background: The present study determines the feasibility of generating an average arterial input function (Avg-AIF) from a limited population of patients with neck nodal metastases to be used for pharmacokinetic modeling of dynamic contrast-enhanced MRI (DCE-MRI) data in clinical trials of larger populations.

    Methods: Twenty patients (mean age 50 years [range 27-77 years]) with neck nodal metastases underwent pretreatment DCE-MRI studies with a temporal resolution of 3.75 to 7. Read More

    Bone turnover markers are correlated with total skeletal uptake of 99mTc-methylene diphosphonate (99mTc-MDP).
    BMC Med Phys 2009 Mar 30;9. Epub 2009 Mar 30.
    Department of Orthopaedics, Malmö University Hospital, Lund University, SE 20502 Malmö, Sweden.
    Background: Skeletal uptake of 99mTc labelled methylene diphosphonate (99mTc-MDP) is used for producing images of pathological bone uptake due to its incorporation to the sites of active bone turnover. This study was done to validate bone turnover markers using total skeletal uptake (TSU) of 99mTc-MDP.

    Methods: 22 postmenopausal women (52-80 years) volunteered to participate. Read More

    Repeatability of regional myocardial blood flow calculation in 82Rb PET imaging.
    BMC Med Phys 2009 Jan 29;9. Epub 2009 Jan 29.
    Division of Nuclear Medicine, The Mount Sinai Medical Centre, New York, NY, USA.
    Background: We evaluated the repeatability of the calculation of myocardial blood flow (MBF) at rest and pharmacological stress, and calculated the coronary flow reserve (CFR) utilizing 82Rb PET imaging. The aim of the research was to prove high repeatability for global MBF and CFR values and good repeatability for regional MBF and CFR values. The results will have significant impact on cardiac PET imaging in terms of making it more affordable and increasing its use. Read More

    Chemotherapeutic treatment efficacy and sensitivity are increased by adjuvant alternating electric fields (TTFields).
    BMC Med Phys 2009 Jan 8;9. Epub 2009 Jan 8.
    NovoCure Ltd,, MATAM Advanced Technology Centre, Haifa 31905, Israel.
    Background: The present study explores the efficacy and toxicity of combining a new, non-toxic, cancer treatment modality, termed Tumor Treating Fields (TTFields), with chemotherapeutic treatment in-vitro, in-vivo and in a pilot clinical trial.

    Methods: Cell proliferation in culture was studied in human breast carcinoma (MDA-MB-231) and human glioma (U-118) cell lines, exposed to TTFields, paclitaxel, doxorubicin, cyclophosphamide and dacarbazine (DTIC) separately and in combinations. In addition, we studied the effects of combining chemotherapy with TTFields in an animal tumor model and in a pilot clinical trial in recurrent and newly diagnosed GBM patients. Read More

    Multiple window spatial registration error of a gamma camera: 133Ba point source as a replacement of the NEMA procedure.
    BMC Med Phys 2008 Dec 9;8. Epub 2008 Dec 9.
    Center for Biomedical Engineering and Physics, Vienna Medical University, Waehringer Guertel 18 - 20, A-1090 Vienna, Austria.
    Background: The accuracy of multiple window spatial resolution characterises the performance of a gamma camera for dual isotope imaging. In the present study we investigate an alternative method to the standard NEMA procedure for measuring this performance parameter.

    Methods: A long-lived 133Ba point source with gamma energies close to 67Ga and a single bore lead collimator were used to measure the multiple window spatial registration error. Read More

    Influence of increased target dose inhomogeneity on margins for breathing motion compensation in conformal stereotactic body radiotherapy.
    BMC Med Phys 2008 Dec 3;8. Epub 2008 Dec 3.
    Julius-Maximilians-University, Department of Radiation Oncology, Wuerzburg, Germany.
    Background: Breathing motion should be considered for stereotactic body radiotherapy (SBRT) of lung tumors. Four-dimensional computer tomography (4D-CT) offers detailed information of tumor motion. The aim of this work is to evaluate the influence of inhomogeneous dose distributions in the presence of breathing induced target motion and to calculate margins for motion compensation. Read More

    Metabolism of no-carrier-added 2-[18F]fluoro-L-tyrosine in rats.
    BMC Med Phys 2008 Nov 7;8. Epub 2008 Nov 7.
    Centre de Recherches du Cyclotron, Université de Liège, Liège, Belgique.
    Background: Several fluorine-18 labelled fluoroamino acids have been evaluated as tracers for the quantitative assessment of cerebral protein synthesis in vivo by positron emission tomography (PET). Among these, 2-[18F]fluoro-L-tyrosine (2-[18F]Tyr) has been studied in mice at a low specific activity. Its incorporation into proteins is fast and metabolism via other pathways is limited. Read More

    NEOadjuvant therapy monitoring with PET and CT in Esophageal Cancer (NEOPEC-trial).
    BMC Med Phys 2008 Jul 31;8. Epub 2008 Jul 31.
    Department of Surgery, Academic Medical Center, Amsterdam, The Netherlands.
    Background: Surgical resection is the preferred treatment of potentially curable esophageal cancer. To improve long term patient outcome, many institutes apply neoadjuvant chemoradiotherapy. In a large proportion of patients no response to chemoradiotherapy is achieved. Read More

    Perfusion scanning using 99mTc-HMPAO detects early cerebrovascular changes in the diabetic rat.
    BMC Med Phys 2008 Mar 13;8. Epub 2008 Mar 13.
    Nuclear Medicine Department, Faculty of Medicine, Kuwait University, Kuwait.
    Background: 99mTc-HMPAO is a well-established isotope useful in the detection of regional cerebral blood flow. Diabetes gives rise to arterial atherosclerotic changes that can lead to significant end organ dysfunction, prominently affecting perfusion to the heart, kidneys, eyes and brain. In the current study, we investigated the role of 99mTc-HMPAO cerebral perfusion scans in detecting early vascular changes in the diabetic brain. Read More

    A computerized infusion pump for control of tissue tracer concentration during positron emission tomography in vivo pharmacokinetic/pharmacodynamic measurements.
    BMC Med Phys 2008 May 30;8. Epub 2008 May 30.
    Uppsala Imanet, Uppsala, Sweden.
    Background: A computer controlled infusion pump (UIPump) for regulation of target tissue concentration of radioactive compounds was developed for use in biological research and tracer development for PET.

    Methods: Based on observed tissue or plasma kinetics after a bolus injection of the tracer an algorithm calculates the infusion needed to obtain a specified target kinetic curve. A computer feeds this infusion scheme into an infusion pump connected to an animal via a venous catheter. Read More

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