Session: 15-01-01: ASME International Undergraduate Research and Design Exposition

Paper Number: 96377

96377 - Bio-Mechanical Engineering a Better Self-Examination Tool 

Introduction:  Cancer patients are often required to monitor skin changes and perform post-surgery checks.  A device assisting patients in performing a hands-free self-examination is desired. Existing products are unaffordable to low income patients, and patients with access criticize device performance. A device that shows improved performance of lesion measurement will surpass competing products in general use.  

Skin lesion size is tracked over time to record healing after gynecologic surgery or advances in disease progression. A mirror and ruler are used in patient homes. Lesion size variation of 1 mm is significant.

In addition to cancer patients, regular wellness examinations are recommended for all women. Patients often use expensive, ineffective commercial products, such as automotive or beauty mirrors which limit hands-free operation or require assistance from another individual. Women of low and moderate income cannot afford existing products. Patients who purchase commercial products have criticized device performance. Current options are inadequate for wellness checks and lesion documentation.

Objective: The aim of this study is to identify what women need to perform a better self-examination and to provide an effective, inexpensive solution to cervical cancer patients.

Materials and Methods: Device functionality and specifications are established through consumer feedback of existing products and review of anatomic dimension studies. Variables include mirror magnification, lighting features, support method, and user adjustment options. Device performance is evaluated by measurement accuracy.

Measurement accuracy is established by comparing user measurement of 3D-printed simulated lesions with a ruler against actual sample dimensions.  The user is provided a hand-held flat mirror (1X magnification) or a hands-free curved mirror (7X magnification). Simple shapes ensure that the required points of measurement are clearly delineated, thus emphasizing the user’s ability to accurately measure lesions and not identify lesion boundaries. Light intensity is recorded. Average absolute errors and standard deviations are determined.

Results: Multiple measurements (n=98) by two users show measurement error is reduced by 46.4% when using a curved mirror. The use of a curved mirror as opposed to a flat mirror result in improvements in measurement accuracy for both lesion types (protrusion and laceration).  Moreover, the use of a curved mirror reduces measurement mistakes.

Increasing light level reduces error when measuring lesions. Accuracy is achieved with standard household bulbs and a minimum light intensity of 131-141 lux. In-device lights in curved mirrors create shadows.

Subjects often undermeasure samples by 0.5-1 mm. Curved mirrors create distortion, but analysis found error was likely due to incorrect use. Users have more difficulty correctly measuring lacerations compared to protrusions.  

Conclusion: A mirror that provides magnification and allows for hands-free operation enables the patient to measure lesions with less error. Testing supports the use of affordable commercial standing mirrors, making examination affordable to all. A design 80% more cost effective than competitors is ready to continue development.

Presenting Author: Caitlin Crowley Purdue University Fort Wayne

Presenting Author Biography: Caitlin Crowley is a 2022 B.S. mechanical engineering graduate of Purdue University Fort Wayne where she studied bio-mechanical engineering. She completed cooperative education rotations in product design and development with Procter & Gamble and Zimmer Biomet starting in 2019. She gained experience in design of medical devices, consumer goods, and plastic products. Caitlin was active on campus through engineering outreach events for women and girls. She continues her engineering career in research & design with Procter & Gamble.

Authors:

Caitlin Crowley Purdue University Fort Wayne
Donald Mueller Purdue University Fort Wayne