Polarization enhanced reflectance imaging for pre-operative delineation of nonmelanoma skin cancers (NMSCs) (Conference Presentation)

Abstract

The objective of this study was to investigate the feasibility of using optical polarization imaging (OPI) for the preoperative delineation of nonmelanoma skin cancer (NMSC) margins. OPI has been previously used for monitoring dermal collagen changes in healthy volunteers in vivo. Since the structure of normal collagen is disrupted in NMSCs, OPI should be capable of delineating skin cancer margins by identifying the disrupted collagen network. Patients with biopsy confirmed NMSCs were recruited under an IRB approved protocol. Prior to imaging, the lesion area was cleaned with alcohol and the intended boundaries of the excision were marked by the surgeon, who was blinded from the imaging results. The imager used narrow band linearly polarized light centered at 440 nm and 640 nm. Cross-polarized reflectance images acquired at 440 nm and 640 nm visualized dermal collagen and the blue marker used by the surgeon to outline the putative lesion boundaries, respectively. The imager provided a 4 cm2 field of view, 200-700µm imaging depth and the light power density at the skin surface of 0.38mW/cm2. Following imaging, routine Mohs procedure was performed using the original markings of the surgeon. After the surgery, images acquired by OPI were compared with the Mohs maps created based on histopathological analysis. Our results indicate that OPI accurately predicts subclinical extension of NMSCs beyond visibly-involved margins in the majority of cases. Therefore, OPI holds the potential to reduce the total number of required surgical stages, possibly minimizing the unnecessary removal of normal tissue.