Document Type

Thesis

Date of Award

1-31-1986

Degree Name

Master of Science in Biomedical Engineering - (M.S.)

Department

Biomedical Engineering Committee

First Advisor

Stanley S. Reisman

Second Advisor

Hans E. Pawel

Third Advisor

David S. Kristol

Abstract

The measurement of facial swelling after oral surgery can indicate the effect of anti-inflammatory drugs. A mechanical device was interfaced to a microcomputer to allow faster calculation of swelling. The mechanical system first established X and Y coordinates on the face. A feeler arm traced out the facial contours and two linear variable differential transformers (LVDTs) related X and Y displacements to voltages which were fed into a microcomputer via an A/D converter. Three BASIC programs were written which facilitated the analysis of patient swelling. MEASUREMENT stored the X-Y voltages from the LVDTs in a patient disk file. CALCULATION filtered the data and determined the volume of swelling. PRINT allowed a printout of areas and volumes of swelling from any patient.

Once the system was operational, it was tested for accuracy and reproducibility. Ten mock acrylic swellings were measured by three methods. The first method consisted of tracing out contours of the swelling on an X-Y plotter. Later, a digital image analyzer determined the areas of swelling, and the volume was calculated by an equation. The X and Y signals were fed into the computer so that the amount of swelling could be determined by software. Finally, the swellings were measured by water displacement. The computer method showed average agreement within 6% compared to water displacement. The system showed 98% agreement between the first and second measurements made on a swelling. Nine measurements made on human patients showed an average difference of 1.2 cc between the computer and the original method.

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