Publications by authors named "Richard Wassenaar"

Unlabelled: Oncolytic virus (OV) therapy has emerged as a novel tool in our therapeutic arsenals for fighting cancer. As a live biologic agent, OV has the ability to target and selectively amplify at the tumor sites. We have reported that a vaccinia-based OV (Pexa-Vec) has shown good efficacy in preclinical models and in clinical trials.

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Purpose: Phase analysis of single photon emission computed tomography (SPECT) radionuclide angiography (RNA) has been investigated for its potential to predict the outcome of cardiac resynchronization therapy (CRT). However, phase analysis may be limited in its potential at predicting CRT outcome as valuable information may be lost by assuming that time-activity curves (TAC) follow a simple sinusoidal shape. A new method, cluster analysis, is proposed which directly evaluates the TACs and may lead to a better understanding of dyssynchrony patterns and CRT outcome.

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Amplitude, defined as the magnitude of contraction of the myocardium, is obtained from phase analysis but has not been investigated to the same extent as phase-based parameters for predicting the outcome of cardiac resynchronization therapy (CRT). The size of scar present in the lateral wall of the left ventricle (LV) has been shown in some studies to predict response to CRT. Scar is associated with impaired regional LV wall motion and is expected to result in a reduction in the corresponding amplitude values derived from phase analysis.

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Purpose: Tumor motion due to patient breathing is a factor that limits the accuracy of dose distribution in radiotherapy. One of the methods to improve the accuracy is by applying respiratory gating or tumor tracking. Both techniques require a precise determination of the spatial location of the tumor.

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Objectives: Phase analysis of SPECT blood pool imaging has the potential to assess mechanical dyssynchrony (MD). However, wall motion of the left ventricle (LV) from SPECT images can be based on either time-activity or time-distance curves. In this paper, these two techniques were compared using receiver-operator characteristics (ROC) analysis at detecting MD patients from a population of normal subjects.

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Introduction: Cardiac resynchronization therapy (CRT) has the potential to improve the outcome of patients suffering from mechanical dyssynchrony and heart failure. It has been suggested that accurate quantification of baseline extent of mechanical dyssynchrony may lead to pre-selection of patients likely to respond to CRT. The standard deviation from a phase histogram (phaseSD), synchrony (S) and entropy (E) are parameters obtained from phase analysis of planar radionuclide angiography (RNA) that may provide an accurate means of assessing mechanical dyssynchrony.

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Unlabelled: (131)I-Tositumomab has been used in treating patients with non-Hodgkin's lymphoma. It is generally recommended that high-energy collimators be used to image patients before they receive (131)I-tositumomab therapy, to determine the effective half-life for therapeutic dose and gross biodistribution. Because many nuclear medicine departments do not possess high-energy collimators, this study was designed to assess the suitability of using medium-energy collimators.

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