Joseph A. Thie

The University of Tennessee Medical Center at Knoxville, Knoxville, Tennessee, United States

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Publications (56)91.21 Total impact

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    ABSTRACT: The aim of the study was to evaluate pulmonary nodules (PNs) by incorporating time sensitivity (S) factor in the retention index (RI) and compare with the traditional fixed interval method. After obtaining approval from the Human Investigations Committee, 97 PNs from 81 patients (age=70±11) referred for dual-time fluorine-18 fluorodeoxyglucose PET (16.1±1.9 mCi) with definite pathological diagnosis or 1-year computed tomography follow-up were retrospectively studied. S=d{ln[SUV]]/d{ln[T]} was obtained by logarithmic regression using scan times, T (0, 1, 2), and standard uptake value (SUV) (0, 1, 2). This time-corrected RI, RIs=[(T2/T1)-1]×100%, was compared with traditional fixed time interval RI, RIx=[(SUV2/SUV1)-1]×100%, by means of receiver operating characteristic curve analysis. The mean±SD of T1 and T2 (72.3±14.0 and 134.9±17.6 min, respectively) skewed markedly from the intended time of PET scans (skewness=2.076 and 1.356, respectively). There were 27 benign tumors, 37 cases of non-small-cell lung cancer, 15 other types of cancer, and 18 stable lesions by 1-year computed tomography follow-up. There were significant differences between the nonmalignant group (NM, n=45) and the cancer group (CA, n=52) in time sensitivity (0.186±0.161 vs. 0.483±0.180, P<0.0005) and RIs (12.7±12.5 vs. 37.4±17.5%, P<0.0005). The RIx showed wider variation than RIs, although the difference between NM and CA was also significant (18.0±28.8 vs. 37.8±32.0%, P=0.002). The RIs and RIx were only weakly correlated (r=0.257, P=0.011). Receiver operating characteristic curve analysis performed for the CA or NM groups revealed a significant improvement in the diagnostic accuracy for malignancy by RIs (area under the curve=0.880±0.035, P<0.0005) compared with RIx (area under the curve=0.694±0.054, P=0.001). Incorporating the time sensitivity factor improves the diagnostic performance of RI for malignant PNs by using additional biologic information from the variation in fluorine-18 fluorodeoxyglucose uptake times and rates.
    No preview · Article · Aug 2014 · Nuclear Medicine Communications
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    Joseph A Thie

    Preview · Article · Dec 2013 · Journal of Nuclear Medicine
  • Joseph A Thie

    No preview · Article · Oct 2012 · Journal of Nuclear Medicine
  • Joseph A. Thie
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    ABSTRACT: Pertaining to a plane containing a line parallel to the long axis of the subject’s body and additionally giving a left or right view. This plane is perpendicular to both the transaxial and coronal planes.
    No preview · Chapter · Jan 2012
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    ABSTRACT: Used synonymously with clearance, the process of a tracer leaving a tissue over time. It can be quantified by the clearance rate.
    No preview · Chapter · Jan 2012
  • Joseph A. Thie
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    ABSTRACT: The absorption by a tissue of some substance, food material, mineral, etc., and its permanent or temporary retention. In imaging this normally refers to the passage of the tracer from plasma into tissue.
    No preview · Chapter · Jan 2012
  • Joseph A. Thie
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    ABSTRACT: A multiplication factor used to obtain an estimated real-world value from a measured or calculated value. The factor is therefore obtained as: known ÷ measured. When referring to a scanner its calibration factor = (known activity concentration at this voxel)/(detectors’ count rate originating from a voxel) and typical units can be (Bq/ml)/(cps/voxel).
    No preview · Chapter · Jan 2012
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    ABSTRACT: Time activity curve. Talairach space A widely accepted standard coordinate system of brain physiologically based regions, that is, an atlas space, to which an individual brain geometry from a scan can be transformed and realigned for purposes of matching corresponding regions among brains. Each point in the individual brain is given Talairach coordinates, (x, y, z) for its location in Talairach space. With the wide variations in individual brain size, shape, and structure, being able to transform region locations into a standard template facilitates comparisons of scans among individuals. See also Broadmann’s area.
    No preview · Chapter · Jan 2012
  • Joseph A. Thie
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    ABSTRACT: Time for the amount of radioactivity in a living organism to be reduced to half of its value existing at an earlier initial time. The amount diminishes due to two concurrent processes: radioactive decay and clearance from the system. If just the former occurs, this effective half-life is independent of initial time and is equal to the isotope’s half-life. When there is biological clearance of a substance, there is also its associated half-life.
    No preview · Chapter · Jan 2012
  • Joseph A. Thie
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    ABSTRACT: A combination of fundamental parameters, such as would involve their products, sums, and quotients. The latter may be, for example, constructed from rate constants obtained from a parameter identification process.
    No preview · Chapter · Jan 2012
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    ABSTRACT: A small foreign object placed usually on the subject’s surface to facilitate scan interpretation and coregistration. This could be a small radioactive source. When used for coregistration, the object must distinctively appear in both images.
    No preview · Chapter · Jan 2012
  • Joseph A. Thie
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    ABSTRACT: Ability to achieve reasonable accuracy and precision in determining a particular parameter when fitting a mathematical model to data. One impediment to identifiability can be high intrinsic correlation coefficients among some parameters, not all of which can then be suitably identified. In such instances, model simplifications would be sought.
    No preview · Chapter · Jan 2012
  • Joseph A. Thie
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    ABSTRACT: A leading trade association in the USA whose members are manufacturers of electroindustry products. One of its useful functions is to provide agreed upon standards for equipment including medical devices. Acronym is NEMA.
    No preview · Chapter · Jan 2012
  • Joseph A. Thie
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    ABSTRACT: Existing conditions, especially those that would be confused with the phenomenon to be observed or measured. As background radiation, it could be an existing measure of radioactivity before any additional would be introduced at that location. Sources of such can include cosmic rays and prior contaminations of an environment. Sometimes the term is used to identify some quantifier of an uninteresting region surrounding a hot spot of interest.
    No preview · Chapter · Jan 2012
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    Joseph A. Thie
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    ABSTRACT: A file compression format mostly used for digitized color and gray scale pictures. This standard approach was created by the Joint Photographic Experts Group to save computer storage space. This storage space can be less than required by an original image’s format, yet preserving its fidelity. Computer filenames would have the ­suffix jpg when using the format.
    No preview · Chapter · Jan 2012
  • Joseph A. Thie
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    ABSTRACT: Picture archiving and communication system used in radiology to manage an encountered multitude of images with associated information for their use in varieties of applications of these. The hardware and software of this system accommodate interfaces among acquisition devices, workstations, mass storage devices, and various other user needs.
    No preview · Chapter · Jan 2012
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    ABSTRACT: An instrument used to image emissions from a subject after the injection of a radioactive drug which releases gamma rays. Both planar imaging and SPECT use gamma cameras. The camera consists of a two-dimensional array of detectors.
    No preview · Chapter · Jan 2012
  • Joseph A. Thie
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    ABSTRACT: An identifying or descriptive marker that is attached to an object. An application in nuclear medicine is where this marker is a tracer having a radioisotope and the object is a blood plasma-carrying substance.
    No preview · Chapter · Jan 2012
  • Joseph A. Thie
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    ABSTRACT: Quality assurance Quality control Programs of regular assessment of facilities and activities to evaluate and ensure that criteria, standards, and procedures are adhered to and that delivered products or services meet performance requirements. This program encompasses all measures taken to verify that the best performance is being obtained from both equipment and procedures. Aspects of quality control can appear in a broad quality assurance program, though sometimes the terms quality control and quality assurance are loosely used interchangeably. Acronym is QA.
    No preview · Chapter · Jan 2012
  • Joseph A. Thie
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    ABSTRACT: The time it takes for a substance to lose half of its pharmacologic, physiologic, or radiologic presence. When time behavior is proportional to exp(−λt), the half-life is related to the decay constant λ as 0.6931/λ. See also biological half-life, effective half-life, and mean life.
    No preview · Chapter · Jan 2012