Because cancer cells divide more rapidly than normal cells, they typically generate more metabolic activity and release more energy as heat. To detect this, Herman [Cila Herman, professor of mechanical engineering] uses a highly sensitive infrared camera on loan from the Johns Hopkins Applied Physics Laboratory. Normally, the temperature difference between cancerous and healthy skins cells is extremely small, so Herman and Pirtini devised a way to make the difference stand out. First, they cool a patient’s skin with a harmless one-minute burst of compressed air. When the cooling is halted, they immediately record infrared images of the target skin area for two to three minutes. Cancer cells typically reheat more quickly than the surrounding healthy tissue, and this difference can be captured by the infrared camera and viewed through sophisticated image processing.
The current pilot study is designed to determine how well the technology can detect melanoma. To test it, dermatologist-identified lesions undergo thermal scanning with the new system, and then a biopsy is performed to determine whether melanoma is actually present.
“Obviously, there is a lot of work to do,” Herman said. “We need to fine-tune the instrument—the scanning system and the software—and develop diagnostic criteria for cancerous lesions. When the research and refinement are done, we hope to be able to show that our system can find melanoma at an early stage before it spreads and becomes dangerous to the patient.”
Alani [Rhoda Alani, adjunct professor at Johns Hopkins Kimmel Cancer Center and professor and chair of Dermatology at Boston University School of Medicine], the skin cancer expert, is also cautiously optimistic. “We, at this point, are not able to say that this instrument is able to replace the clinical judgment of a dermatologist, but we envision that this will be useful as a tool in helping to diagnose early-stage melanoma,” Alani said. “We’re very encouraged about the promise of this technology for improving our ability to prevent people from actually dying of melanoma.”
The researchers envision a hand-held scanning system that dermatologists could use to evaluate suspicious moles. The technology also might be incorporated into a full-body-scanning system for patients with a large number of pigmented lesions, they said.