In order to evaluate the proper breast implant, the surgeon relies on a standard set of measurements manually taken on the subject. This approach does not allow to obtain an accurate reconstruction of the breast shape and asymmetries can easily arise after surgery. Purpose of this work is to present a method which can help the surgeon in the choice of the shape and dimensions of a prosthesis allowing for a perfect symmetry between the prosthesis and the controlateral breast and can be used as a 3D visual feedback in plastic surgery. The breast 3D shape is reconstructed starting from a set of 3D points which are small spots produced by three optical pens (semiconductor lasers, 670nm, 5mW) manually moved over the breast skin. These spots are surveyed by four specially designed CCD cameras and their 2D position on the camera targets is computed at a sub-pixel accuracy (0.1 pixels) through a real-time cross-correlation implemented on a VLSI custom board (ELITE system). These co-ordinates are sent to a host computer which determines and visualises the 3D position of the points in real-time. Starting from these points, a continuous description of the 3D surface is obtained through a linear combination of weighted Gaussian functions (Radial Basis Network). The weights are estimated through a maximum a-posteriori estimate carried out on a local sub-set of the data points. Starting from this continuos reconstruction of the surface in 3D space, it is possible to identify the overall volume as well as the shape of whichever section of the breast, which constitute the information needed by the surgeon to evaluate and adapt the proper implant. Moreover, this allows an easy follow up of the skin expansion after the implantation of the expander in the months next to the surgery. The same 3D scanner can be used to get a virtual 3D model of the actual breast which can be interactively modified with the patient in order to achieve a desired shape with aesthetic plastic surgery. The simplified structure of the system allows to define it as portable and therefore it allows to take measurements easily outside the hospital with very high accuracy. The reconstruction algorithm allows to get 3D reliable data and a compact and easy way to manipulate a virtual model of the breast surface. Such a system can be of extreme help to assist the surgeon before plastic implants and before corrective plastic surgery. Its main advantages on other methods are the flexibility in terms of size of objects that can be scanned and in the absolutely non contact, non constraining data acquisition procedure and the high accuracy that can be attained.
|Titolo:||Portable and accurate 3D scanner for breast implants design and reconstructive plastic surgery|
BORGHESE, NUNZIO ALBERTO (Secondo)
|Parole Chiave:||RBF network ; surface scanning ; real time ; opto-electronic system ; computer graphics ; mammary surgery.|
|Data di pubblicazione:||1998|
|Digital Object Identifier (DOI):||10.1117/12.310946|
|Tipologia:||Book Part (author)|
|Appare nelle tipologie:||03 - Contributo in volume|