Publications by authors named "J D Trzasko"

ATM inhibitors are being developed as radiosensitizers to improve the antitumor effects of radiotherapy, but ATM inhibition can also radiosensitize normal tissues. Therefore, understanding the elevated risk for normal tissue toxicities is critical for radiosensitizer development. This study focused on modeling the relationship between acute mucosal toxicity, radiation dose, fractionation schedule, and radiosensitizer exposure.

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Purpose: To study implant lead tip heating because of the RF power deposition by developing mathematical models and comparing them with measurements acquired at 1.5 T and 3 T, especially to predict resonant length.

Theory And Methods: A simple exponential model and an adapted transmission line model for the electric field transfer function were developed.

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Article Synopsis
  • This study explored how aging and sex affect the stiffness of the heart's left ventricle using a technique called MR elastography (MRE) in 109 healthy volunteers aged 18-84.
  • Results showed that left ventricular shear stiffness significantly increased with age in women but not in men, alongside changes in ejection fraction and end-systolic volume for women.
  • The findings suggest that MRE can effectively measure these differences, indicating that aging impacts women more markedly than men when it comes to heart muscle stiffness.
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Numerous physiological processes are cyclical, but sampling these processes densely enough to perform frequency decomposition and subsequent analyses can be challenging. Mathematical approaches for decomposition and reconstruction of sparsely and irregularly sampled signals are well established but have been under-utilized in physiological applications. We developed a basis pursuit denoising with polynomial detrending (BPWP) model that recovers oscillations and trends from sparse and irregularly sampled timeseries.

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Background: Echo planar imaging (EPI) is a fast measurement technique commonly used in magnetic resonance imaging (MRI), but is highly sensitive to measurement non-idealities in reconstruction. Point spread function (PSF)-encoded EPI is a multi-shot strategy which alleviates distortion, but acquisition of encodings suitable for direct distortion-free imaging prolongs scan time. In this work, a model-based iterative reconstruction (MBIR) framework is introduced for direct imaging with PSF-EPI to improve image quality and acceleration potential.

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