Award Date

1-1-2000

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Health Physics and Diagnostic Sciences

First Committee Member

Steen Madsen

Number of Pages

84

Abstract

The response of a p-type diode detector for use in patient dose monitoring in photon and electron fields was evaluated for a number of commonly-encountered clinical parameters. Effects of energy, field size, source-to-surface distance, presence of beam modifiers, beam orientation, and temperature were investigated. Shielding effects and batch variations were also examined. In most cases, diode performance was in good agreement with manufacturer's specifications and/or the results of others using similar detectors. Variations in excess of +/-12 % were observed in high-energy wedged fields over the source-to-surface distances investigated. Reductions in local dose directly behind the diode due to electron shielding ranged from 8 to 12%. Entrance and exit dose measurements were made on patients undergoing treatment for lung or prostate carcinoma. Differences in measured and calculated exit doses could be improved by the inclusion of tissue heterogeneity correction factors in the treatment planning algorithm.

Keywords

Characterization; Detectors; Dosimetry Semiconductor; Silicon; Type; Vivo

Controlled Subject

Oncology; Diagnostic imaging

File Format

pdf

File Size

1863.68 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

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