Award Date

1-1-2007

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Allied Health and Human Performance

First Committee Member

Phillip W. Patton

Number of Pages

72

Abstract

With approximately one in six men affected by prostate cancer at some point in their lives, effective treatment of the disease remains a focus of oncology research. Effective treatment using radiation requires the delivery of a significant dose to the prostate volume while sparing surrounding sensitive structures. Treatment success can then be determined by localization of the seeds following implantation and the calculation of a dose distribution across the target volume. Magnetic Resonance Imaging (MRI) yields images with soft tissue contrast that is superior to CT or ultrasound, but has been under-appreciated as a dosimetric tool due to the difficulty in localizing the implanted seeds; To optimize scan parameters for seed localization, a phantom was constructed of tissue-equivalent gelatin. Seeds were implanted during construction so various scan protocols could be tested for seed visualization and volume calculation prior to patient studies. Five healthy volunteers and five patients with permanently implanted seeds were then imaged to validate the phantom studies. Images were evaluated based on anatomical clarity and seed visualization rates; Optimization of the scan protocols for use with this equipment yields images with clearly defined anatomical boundaries as well as clearly defined seeds. Phantom volume measurements deviated from known values by less than 2.5% T2-weighted images provide superior anatomical delineation, but suffer from broad susceptibility artifacts that make determination of seed locations difficult. Proton density-weighted images clearly show seed locations and tissue margins. The selection of a 1 mm slice thickness and a 4 mm interstice gap allowed maximum seed visualization rates of 93.3%; Keywords: prostate, brachytherapy, dosimetry, magnetic resonance imaging.

Keywords

Delineation; Localization; Magnetic; Prostate; Resonance; Seed; Spectrometer Volume

Controlled Subject

Radiation; Nuclear physics; Diagnostic imaging

File Format

pdf

File Size

1474.56 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

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