Session: 06-05-01: Biomedical Devices, Sensors, and Actuators

Paper Number: 143133

143133 - Anatomical Data Acquisition Protocol Using Low-Cost 3d Scanners for Project Zule: 3d-Printed Breast Prostheses for Women Undergoing Mastectomy 

Three-dimensional (3D) scanning has become a prevalent tool for acquiring anatomical information from subjects, providing a map of the patient's external body topology. However, cutting-edge 3D scanning equipment can be very expensive, making it inaccessible to some healthcare facilities in developing countries. While low-cost 3D scanners are available, they have limitations that necessitate addressing for reliable data acquisition.

Project Zule focuses on creating personalized external breast prostheses using additive manufacturing to address the high prevalence of breast cancer.  A key project goal is to fabricate a prosthesis that replicates the female breast, not only in shape but also in its static and dynamic behavior when placed within a brassiere. Therefore, a study to assess breast deformation while supported by a standard brassiere is necessary. This study involves 3D scanning sessions of healthy female volunteers who have consented to being scanned with and without a bra. Since Project Zule targets women with limited resources in developing countries, a low-cost 3D scanner is employed.

A significant challenge encountered during this project was the difficulty in comparing two scanning sessions of the same subject: with and without the brassiere. This necessitated the development of a standardized data acquisition protocol for 3D scanning. This protocol facilitates the subsequent creation of customized breast prostheses through accurate capture of breast topography.

 

To facilitate protocol development, a global reference frame was established utilizing a static fiducial marker positioned at a constant distance from the patient throughout the entire acquisition process. This marker serves as the origin and defines the orientation of the coordinate system with respect to the patient's anatomy, employing a right-handed Cartesian coordinate system (X, Y, Z). To optimize digital reconstruction fidelity, an experimental evaluation was conducted to determine the optimal geometric configuration for the marker. A hybrid design consisting of a pyramid and a cuboid (square-based prism) was chosen due to its superior stability and robustness within the virtual environment. Additionally, a patient-centric local coordinate system was established to align with subject anatomy for precise representation of captured data. These standardized reference points enable the quantification of breast volume, morphology, and bilateral symmetry. The measurement protocol incorporates a six-degrees-of-freedom coordinate system, capturing frontal, lateral, and posterior views.

Thirty volunteers underwent 3D scans with and without a bra using a Structure Sensor (58° horizontal, 45° vertical FOV, Occipital, San Francisco). Standardized acquisition ensured a minimum 2-square-meter space, using a 120 cm radius canvas aligned with the patient's coordinate system, a reference marker 80 cm from the center, and supine patient positioning with secured hair and arms at sides. The scanner operator maintained a 50 cm distance from the 120 cm reference frame origin.

 

Three data capture scenarios were analyzed to identify the optimal scanning method: the first with 360° rotation, the second with 180° rotation using the marker in both scans, and the third with 360° rotation without reference systems or the marker. Following the acquisition of digital scans capturing the patient's anatomy, the images of each volunteer were imported into computer-aided design (CAD) software. By overlapping these images, anatomical convergent landmarks were identified.

Analysis revealed that a 360° rotation scan incorporating the reference marker yielded the most precise data acquisition protocol. This method achieved a remarkably low standard deviation of 0.1816 mm, signifying high precision in volumetric breast capture.

Presenting Author: Carlos G. Helguero ESPOL Polytechnic University

Presenting Author Biography: Carlos G. Helguero is a full-time Mechanical Engineering Department (FIMCP) professor at ESPOL Polytechnic University. He received his PhD in Mechanical Engineering, in the biomedical engineering area, from SUNY Stony Brook University – USA.
His research interests include applications of additive manufacturing to solve biomedical engineering problems. In this field, among his projects is the development of 3D-printed surgical guides for osteosarcoma-related surgeries. He is also interested in studying the feasibility of applying 3D-printed medical models for surgery planning and education. Moreover, he is developing a methodology to design and 3D-print orthosis for member immobilization. Finally, he is currently conducting a project to create a 3D-printed breast prosthesis for women under the mastectomy procedure.

Authors:

Carlos G. Helguero ESPOL Polytechnic University
Jose Cansing ESPOL Polytechnic University
Fausto A. Maldonado ESPOL Polytechnic University
Carlos Saldarriaga ESPOL Polytechnic University
Jorge L. Amaya-Rivas ESPOL Polytechnic University