• Roberto Accorsi, a doctoral candidate in nuclear engineering, uses a Coded Aperture Camera for medical imaging.

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  • Bone scans of a mouse with a high-resolution collimator (the technology currently in use) at top, and with Roberto Accorsi's new Coded Aperture Camera (bottom).

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Airport detection research yields better medical imaging

Research funded by the Office of National Drug Control Policy and the Federal Aviation Administration to develop more effective ways to detect drugs and explosives appears to be yielding results that could have a major impact on nuclear medicine imaging.

Roberto Accorsi, a doctoral candidate in nuclear engineering, has adapted technology developed by astronomers to study the stars to a Coded Aperture Camera (CAC) that provides better resolution than current state-of-the-art medical imaging systems (1.5mm instead of the current 4.5mm).

Mr. Accorsi has been working on the project for two years with Senior Research Scientist Richard C. Lanza, who is the advisor on his doctoral research.

"We realized that looking at cargo containers isn't the same as looking at stars and that the methods used in the past were not going to work because they put spurious artifacts in the pictures," said Dr. Lanza. "Roberto discovered the reasons for these problems and not only understood their origin but came up with a cure. We built a small system to test the ideas and they proved correct. The even nicer thing was that the small model proved ideal for nuclear medicine."

Nuclear medicine imaging produces images that show the areas marked by radioactive molecules taken orally or injected in the patient. Mr. Accorsi has used the CAC to produce clear images of mice. He believes a properly scaled CAC has the potential to produce the same clear images for human patients.

By taking two pictures through an anti-symmetric Tungsten aperture and rotating the aperture 90 degrees for the second image, Mr. Accorsi creates an artifact-free digital image of the entire field of view. Other factors being equal, the CAC images have much better resolution and a better signal-to-noise ratio than those made using other systems.

"Interestingly enough, the Office of National Drug Control Policy thought we were building a system for dealing with drugs on the supply end and were delighted to find that we could use the methods to work on the demand end and find the reasons for addiction," said Dr. Lanza.

"We have had a good result and there is great enthusiasm for the work," said Mr. Accorsi, who holds a bach-elor's degree in nuclear engineering from Politecnico di Milano in his native Italy and came to MIT for graduate studies in 1996.

Mr. Accorsi, who has had a longtime interest in optics, discovered the possibilities in the field of medical imaging at MIT, under the tutelage of Dr. Lanza. "We didn't have nuclear medicine in Milan," said Mr. Accorsi, who believes medical applications may be the future in nuclear engineering.

Mr. Accorsi has moved the CAC from the windowless laboratory in the basement of Building NW13 to the Massachusetts General Hospital annex in Charlestown, where he is continuing to refine his technique. His dank MIT surroundings led him to the MIT Sailing Club in search of sunlight and serenity. He has become an avid sailor.

"The lab can be dark and depressing," said Mr. Accorsi, who had not sailed before coming to MIT. "So I took lessons and started going on moonlight sails. Being on the water eases the tension and helps me keep my sanity."

A version of this article appeared in MIT Tech Talk on November 8, 2000.

Topics: Health sciences and technology, Innovation and Entrepreneurship (I&E), Nuclear science and engineering


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