As a result, earlier treatment can be administered and patients without cancer won t have to worry so long about the possibility of having it. For the optical biopsy test, while the patient is sedated, the doctor inserts an endoscope an instrument that allows visual examination of the interior of an organ such as the stomach through her mouth and into her esophagus. Traveling through the optical fiber in the endoscope, blue light from a pulsed nitrogen dye laser illuminates tissue in the patient s esophagus. An optical fiber cable is inserted in another channel of the endoscope to collect and transmit light produced by her esophageal tissue after it is excited by laser light. Upon absorbing the light, the tissue emits light with a characteristic pattern of wavelengths, called a laser-induced fluorescence spectrum.
Normal tissue has a spectral pattern different from that of cancerous tissue.
Vo-Dinh and his colleagues developed an algorithm that enables a computer to compare the measured fluorescence patterns with the known spectral characteristics of light from both cancerous and normal esophageal cells. The light pattern from the woman s cells matched that of cancerous cells. She also learned from the surgical biopsy that she has a cancerous tumor but, because it s in an early stage, treatment should make her well. Vo-Dinh says, we are planning to develop optical biopsy techniques for use in detecting cancer in the colon, cervix, lung, and bladder. When you re hit over the head, blood from an artery may begin spilling between your skull and brain.