The Mathematics of Cancer Treatment
Advanced programming techniques offer new weapon against prostate cancer.

A merger of advanced mathematical techniques with cutting-edge computer technology may give doctors a powerful new weapon in the battle against prostate cancer.

photo by Gary Meek Researcher Eva Lee explains how a computerized expert system helps plan the placement of radioactive seeds for prostate cancer treatment. Shown are an ultrasound image of a prostate, a section of the optimization algorithm and a medical illustration of the prostate.

Researchers have developed a computerized expert system that would help radiation oncologists optimize placement of radioactive "seeds" for prostate brachytherapy, a non-surgical treatment that has been growing in popularity. Beyond providing treatment more precisely tailored to each patient, the system targets escalated doses of radiation at tumor pockets, and accounts for changes that occur in the prostate volume during treatment. Use of the system has the potential to improve tumor control and reduce uncomfortable side effects.

For the cost-conscious medical industry, the automated system offers a dramatic reduction in the time required to design radioactive seed treatment, allowing optimized plans to be created in minutes – and revised as the procedure proceeds.

"The system allows us to effectively manipulate the large number of variables involved, something that is far too complex for even the best human experts," says Eva K. Lee, an assistant professor of industrial and systems engineering at the Georgia Institute of Technology and of radiation oncology at Emory University School of Medicine. "We can deliver better precision and create the optimal plan for each patient. This system should help cut the recurrence rate for prostate cancer and reduce toxicity to healthy tissue."

Prostate brachytherapy involves implantation of tiny radioactive seeds in the cancerous prostate. Continuous radiation from the seeds kills the cancer cells, allowing patients to avoid surgery that can produce such complications as incontinence and impotence.

To successfully treat the cancer, however, physicians must carefully design the radiation dose, balancing the high radiation levels needed to eradicate the cancer against the need to protect nearby tissue, including the urethra and rectum. Further complicating treatment is the edema that occurs as needles are inserted to place the seeds. Resulting changes in prostate volume can mean delivering too little radiation at the beginning of treatment and too much as the swelling subsides.

"It is very complicated to produce a successful implant," explains Lee, who collaborated on the work with Macro Zaider, professor and head of brachytherapy physics at Memorial Sloan Kettering Cancer Center. "Proper coverage of the entire prostate is very important, but it can be very difficult to carry out the plan. The seeds cannot always be placed in the location you want, so you must be able to compensate for that. Our system allows real-time planning, and corrections can be made as you proceed."

Ultrasound images of the patient's prostate are used by the system to help determine optimal radioactive seed placement based on such variables as prostate volume, location of tumor pockets, radioactivity levels of the seeds, location of the urethra (which passes through the prostate) and regions of the organ that may be unreachable by placement needles. Mixed integer programming and computational optimization techniques are the core technological tools utilized.

Woven into the system are a dose-calculation engine, a modeling module, an optimization engine and a graphical evaluation tool. Features include (1) real-time automatic design of seed configuration for use in the operating room, (2) incorporation of magnetic resonance spectroscopy imaging information to target escalated doses to tumor regions, (3) planning that accounts for changes in prostate volume, and (4) an ability to correct seed configuration intra-operatively to account for seed displacement, needle distortion, or unforeseen difficulties encountered during implantation.

"To the physician, this will be a black box," Lee explains. "They will not need to know what is going on with the mathematics. All they will have to do is tell the system what they want in the plan."

Less experienced oncologists working in remote areas could use the system to aid in producing high-quality treatment plans.

In most current treatments, seed placement is determined manually based on a simulation of the patient's prostate. Done days or weeks ahead of the operation, this "pre-plan" takes hours to produce. By cutting the planning time to as little as 15 minutes, the system should reduce costs and allow physicians to spend more time with their patients, Lee notes.

Though the expert system is ready for commercialization, it will have to receive FDA approval before being made available to treatment centers. However, Lee has used real patient data to compare her system against treatment plans designed by radiation oncologists. Those results suggest the system will provide significant improvements in treatment outcomes.

The system operates on a wide range of computing platforms, including Windows NT personal computers.

The work is sponsored by the National Science Foundation and the Whitaker Foundation.

– John Toon

The full-text news release version of this article is posted at gtresearchnews.gatech.edu/newsrelease/lee/lee_news.html. For more information, you may contact Eva Lee, School of Industrial and Systems Engineering, Georgia Tech, Atlanta, GA 30332-0205. (Telephone: 404-894-4962) (E-mail: eva.lee@isye.gatech.edu).

Replacing Brawn with Brains
Advanced software algorithms make automation more affordable.

Advanced software algorithms developed at the Georgia Institute of Technology are the foundation for a new robotic motion control system that will help manufacturers reduce the labor involved in routine inspection and material handling tasks.

photo by Randal Crow Johnny Dempsey, left, plant manager, and David Boyd, president of Vulcan Group Inc., examine a part prior to loading into the CAMotion robot for inspection. The Birmingham company uses CAMotion systems to inspect automobile roof racks and to load the racks into shipping containers. (300-dpi JPEG version - 499k)

Produced by Atlanta-based CAMotion Inc., the PC-based software provides greater intelligence for automated operations, allowing off-the-shelf, low-cost robotic equipment to handle tasks previously requiring more precise and much heavier components. CAMotion, whose name is derived from "computer assisted motion," is a member company of the Advanced Technology Development Center (ATDC) at Georgia Tech.

Though initially targeting manufacturers, the motion control systems could ultimately be used in the service industry, where menial tasks and low wages also make it difficult to maintain a competent staff. Traditional robotic systems have already brought about significant productivity gains in manufacturing processes that involve highly repetitive, difficult and dangerous tasks. CAMotion, however, is taking aim at processes that are now often not cost-effective to automate: assembly operations, loading and unloading containers or machines, and inspecting products for quality standards.

"Our goal is to help companies apply automation to routine and menial tasks, the very things that companies have trouble finding people to do these days, and the things that often keep U.S. manufacturers from being competitive," says Steve Dickerson, a professor emeritus of mechanical engineering and chairman of the company. "If you look at what people do in factories and in the service sector, direct labor is now almost entirely used for motion.

"The fact that people have good hand-eye coordination and the intelligence to know the next task means that people in manufacturing are used almost exclusively for moving things around," he explains. "These tasks do not require the same precision as placing components onto a circuit board, but the large-scale motions across three dimensions have made them difficult to automate in a cost-effective way."

CAMotion's first customer is Vulcan Group in Birmingham, Ala. The company uses two CAMotion systems, one to inspect automobile roof racks after painting, and the other to stack the completed parts in a shipping container. As part of the inspection task, a gantry-type robot moves both the parts and the vision system to acquire 24 different images of each part to evaluate them for paint quality.

"CAMotion created a solution for us when no one else could" says David Boyd, president of Vulcan Group. "We are very pleased with the system; in fact, we believe that it will revolutionize the way painted parts are inspected in the automotive industry."

Three types of algorithms, all developed by researchers in Georgia Tech's Manufacturing Research Center, are included in CAMotion's software:

• A vibration control algorithm plans the robotic axis trajectory in such a way as to avoid creating unnecessary oscillation. By "damping out" the vibration, the "intelligent trajectory" allows the use of lighter and less expensive components.

• A learning algorithm helps the equipment to improve its own performance based on feedforward. This typically produces a 10-to-1 reduction in dynamic error.

• Position estimation software, combining machine vision, encoders and accelerometers, helps the system know its own location relative to the work and thus how to move to accomplish a task.

"We can build a machine that is not as rigid and precise because our software compensates for that," says Bob Purcell, the company's president. "Therefore, we can build automation equipment with the same level or a higher level of performance at less expense. What differentiates us is the ability to produce a machine that is very cost effective for a variety of tasks."

By using standard components and smart software control, Purcell hopes to make automating those tasks competitive given the rising cost and scarcity of direct labor. Beyond the use of standard robotic components, CAMotion will use a single software package for all of its applications.

Changes to numerical tables in the software allow it to handle a wide range of different tasks, providing a degree of flexibility that has been lacking in automated systems. The software behind CAMotion was developed with support from the National Center for Manufacturing Sciences, a consortium of manufacturers. Faculty members working on that project, including Wayne Book, Nader Sadegh and Dickerson, saw the business potential for the techniques and obtained a $50,000 Faculty Research Commercialization Program grant from the ATDC to move their research toward commercialization.

– John Toon

The full-text news release version of this article is posted at gtresearchnews.gatech.edu/newsrelease/CAMOTION.html. For more information, you may contact Bob Purcell, CAMotion Inc., 430 10th St., Atlanta, GA 30318. (Telephone: 404-874-0090) (E-mail: bob.purcell@mindspring.com).

Faculty Awards and Honors
Georgia Tech faculty and staff receive recognition.

Barbara Blackbourn-Jansma of the School of Modern Languages was nominated as International Poet of the Year. She has also been named International Poet of Merit and was invited to compete at the International Society of Poets Spring Convention and Symposium in early March for International Poet of the Year 2001.

Jeffrey A. Davis of the School of Electrical and Computer Engineering received a National Science Foundation CAREER Award for "Interconnect Dominant Ultra Large-Scale Integrated Design: A New Paradigm for 21st Century Integrated Circuit Design and Education."

Imme Ebert-Uphoff of the School of Mechanical Engineering won the 2001 Robert W. Galvin Outstanding Young Manufacturing Engineer Award from the Society of Manufacturing Engineers.

Mostafa El-Sayed of the School of Chemistry and Biochemistry was elected a fellow of the American Physical Society. This is in addition to his election this year as a fellow of the American Association for the Advancement of Science.

Nicholas V. Hud of the School of Chemistry and Biochemistry received a Research Innovation Award from Research Corporation to support his research into the development of novel methods for controlling DNA condensation.

Gary B. Schuster, dean of the College of Sciences, was elected chairman of the American Association for the Advancement of Science Section on Chemistry.

C. David Sherrill of the School of Chemistry and Biochemistry received the International Journal of Quantum Chemistry Young Investigator's Award.

Charles Ume of the School of Mechanical Engineering was named the co-editor-in-chief of Mechatronics: An International Journal.

Kurt Wiesenfeld of the School of Physics was elected a fellow of the American Physical Society. The citation reads: "For seminal theoretical contributions to nonlinear dynamics and complex systems theory, including co-discovery of self-organized criticality and for theories of stochastic resonance and Josephson-junction phase locking."

Also see Research Notes news stories.

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Last updated: July 14, 2001