WEST LAFAYETTE, Ind. -- The response of tumors to anticancer drugs has been observed in real-time 3-D images using technology developed at Purdue University.
The new digital holographic imaging system uses a laser and a charged couple device, or CCD, the same microchip used in household digital cameras, to see inside tumor cells. The device also may have applications in drug development and medical imaging.
"This is the first time holography has been used to study the effects of a drug on living tissue," said David D. Nolte, the Purdue professor of physics who leads the team. "We have moved beyond achieving a 3-D image to using that image for a direct physiological measure of what the drug is doing inside cancer cells. This provides valuable information about the effects of various doses of the drug and the time it takes each dose to become significantly effective."
The laser is gentle and does not harm living tissue, Nolte said. The cancer cells used for the research were grown independently in a bioreactor in the laboratory.
Holography uses the full spectrum of information available from light, more than what the human eye can detect, to create a 3-D image called a hologram. By shining a laser on both the object and directly on the CCD chip of the digital camera, the system screens the pattern of light reflected back from the object and allows the camera to record very detailed information, including depth and motion on a scale of microns, or 0.0001 centimeter.
The scattered light waves reflected back from the object come together at the camera's detector and form what is called "laser speckle." To the eye, this speckle appears as a random pattern of blotches of bright and dark, but the pattern changes if there is motion within the object.
"All living matter is in constant motion, and the laser speckle from a living object is constantly changing with that motion," Nolte said. "This was the key to the d
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