Polarization Enhanced Wide Field Optical Imaging for Preoperative Delineation of Nonmelanoma Skin Cancers

The purpose of the study is to evaluate the ability and efficacy of using a polarization-enhanced reflectance and fluorescence imaging device, PERFIS, (see the Device Brochure) for demarcation of nonmelanoma skin cancer margins prior to surgery. PERFIS is a harmless and non-invasive device that has been used to image biological tissue both in vitro and in vivo. In this study it will be used to image nonmelanoma skin cancer lesions prior to surgery. The use of PERFIS will not affect patient care or treatment decisions in any way. No extra tissue will be used for imaging.

Prior to imaging, the patient's lesion will be prepared, and cleansed per routine aseptic technique. Based on visual inspection, the major and minor axes of the tumor will be marked exactly at the apparent tumor margins, to ensure unbiased tumor excision. For marking, the investigators will use a sterile blue marking pen that will not be visualized in the optical polarization images at 440 nm. After marking, the length of the major and minor axes of the tumor will be measured using a ruler. A photograph of the tumor (and ruler as a reference scale) will be taken. After measuring and photographing, polarized reflectance optical imaging using the PERFIS device will be performed.

Photographs of the PERFIS imaging device are presented in the Device Brochure. During imaging, the tumor and surrounding skin will be illuminated by a continuous wave low intensity monochromatic light from a non-coherent light source (Xe-arc lamp combined with interference filters) at the wavelength of 440 nm, with a power density on the skin of approximately 0.4 mW/cm2. This power density is well below standard safety thresholds. No other wavelengths or power densities will be utilized in this study. The light illuminator is controlled by a shutter which remains closed except during user-controlled image capture. Imaging will be initiated once the PERFIS device is positioned on the surface of the patient's skin. The shutter opens and closes automatically to facilitate imaging. This process ensures light will be transmitted only to the surface of the skin, thus minimizing the risk of potential accidental eye exposure. Imaging requires only a few minutes and is entirely noninvasive.

After imaging, local anesthesia will be administered, using 1% lidocaine with epinephrine by deep dermal infiltration. The lesion will be prepared and cleansed per routine aseptic technique. Surgical excision of the tumor will be performed using standard Mohs technique. A regular photograph of the wound bed (and ruler as reference) will be taken. No extra tissue will be excised for research imaging purposes.

The excised tumor lesion will then undergo standard Mohs frozen histopathological preparation with Hematoxylin and Eosin (H&E) staining. Dr. Neel will analyze the histological slides and record presence and location of residual tumor cells. He will not utilize the images generated by PERFIS for his clinical decision making. After confirming that the excision margins are free of tumor cells by histological evaluation, standard post-Mohs protocol will be performed.