Colorectal polyps mimicking phantoms for OCT application

摘要

Tissues-mimicking phantoms are widely used for performance evaluation of imaging systems. Disease specific design of the phantom is necessary for the correct assessment of a system's parameters. Such phantoms are a key requirement for the continued development of various imaging techniques such as optical coherence tomography (OCT), which has been successfully applied for diagnosis of diseases in the esophagus and preliminary data show that it can be also highly perspective for diagnosis of colorectal cancer. However, in vivo validation of this novel optical approach is often difficult, since the disease model development in large animals, such as pigs, is a quite challenging task. The optimal colorectal cancer phantoms should have the following criteria: 1) realized geometry in three dimensions, 2) customizable material and optical properties, 3) mounting system allowing placement in various locations of the bench-top colon model (plastic or tissue) and removal using standard endoscopic tools, 4) visual appearance compatible with white light endoscopic imaging, and 5) long term stability. To match all these criteria, we propose tissue-mimicking phantoms prepared using 3D printing and PDMS/TiO_2 insertions for cancer-like regions that are covered with the layer of Dragon skin to color-match the mucosa appearance, as we believe these materials are the most promising for durable and accurate replication of tissue properties. The polyps are mounted in the colon using small neodymium magnet embedded in the base of the polyp. The developed polyps were evaluated using optical coherence tomography system.