Pilot study for detection of cutaneous melanoma boundary using photoacoustic imaging

The standard method to treat cutaneous melanoma, which is the most prevalent skin cancer, is surgical excision of visible boundary with an additional margin. The margin is typically decided by surgeons' experience based on the color of the lesion. It is very important to determine appropriate excision area because the operation will continue until a histological evaluation is made the there is no cancerous cells in the excised margin. Here, we demonstrate the results from our initial pilot study for detection of melanoma boundary using photoacoustic (PA) imaging. We recruited a patient who had a cutaneous melanoma lesion on the left heel. We excised the lesion with surgical operation by adding ∼1 cm margin to the visible boundary, and then immediately acquired multispectral PA images of the lesion. By scanning a linear array transducer using a motorized stage, we acquired volumetric PA images of the lesion. From the multispectral analysis of PA signals, we could tell cutaneous melanoma from surrounding normal tissue and marking pen. Although much more studies are required for clinical evaluation, the initial results demonstrate that the PA imaging can provide additional information to surgeons for better selection of excision area of cutaneous melanoma.