PHILADELPHIA, PA (July 21, 2010) -- A group of researchers from Wake Forest University Baptist Medical Center is developing a way to treat cancer by using lasers to light up tiny nanoparticles and destroy tumors with the ensuing heat.
Today at the 52nd Annual Meeting of the American Association of Physicists in Medicine (AAPM) in Philadelphia, they will describe the latest development for this technology: iron-containing Multi-Walled Carbon Nanotubes (MWCNTs) -- threads of hollow carbon that are 10 thousand times thinner than a human hair.
In laboratory experiments, the team showed that by using an MRI scanner, they could image these particles in living tissue, watch as they approached a tumor, zap them with a laser, and destroy the tumor in the process.
If this sounds like science fiction, it is not. The work builds on an experimental technique for treating cancer called laser-induced thermal therapy (LITT), which uses energy from lasers to heat and destroy tumors. LITT works by virtue of the fact that certain nanoparticles like MWCNTs can absorb the energy of a laser and then convert it into heat. If the nanoparticles are zapped while within a tumor, they will boil off the energy as heat and kill the cancerous cells.
The problem with LITT, however, is that while a tumor may be clearly visible in a medical scan, the particles are not. They cannot be tracked once injected, which could put a patient in danger if the nanoparticles were zapped away from the tumor because the aberrant heating could destroy healthy tissue.
Now the team from Wake Forest Baptist has shown for the first time that it is possible to make the particles visible in the MRI scanner to allow imaging and heating at the same time. By loading the MWCNT particles with iron, they become visible in an MRI scanner. Using tissue containing mouse tumors, they showed that these iron-containing MWCNT particles could destroy the tumors when hit with a laser.
"To find the exact location of the nanoparticle in the human body is very important to the treatment," says Xuanfeng Ding, M.S., who is presenting the work today in Philadelphia. "It is really exciting to watch the tumor labeled with the nanotubes begin to shrink after the treatment."
The results are part of Ding's ongoing Ph.D. thesis work -- a multi-disciplinary project led by Suzy Torti, Ph.D., professor of biochemistry at Wake Forest Baptist, and David Carroll, Ph.D., director of the Wake Forest University Center for Nanotechnology and Molecular Materials, that also includes the WFB Departments of Physics, Radiation Oncology, Cancer Biology, and Biochemistry.
A previous study by the same group showed that laser-induced thermal therapy using a closely-related nanoparticle actually increased the long-term survival of mice with tumors. The next step in this project is to see if the iron-loaded nanoparticles can do the same thing.
If the work proves successful, it may one day help people with cancer, though the technology would have to prove safe and effective in clinical trials.
Dan Bourland, Ph.D., associate professor of radiation oncology and Ding's advisor, praises the high quality of Ding's work and says that the project is a strong example of today's "team science" that is needed for success in the biomedical fields.
The presentation "MR Relaxation Properties for Fe-Containing MWCNTs and Potential for Combined MR Imaging and Tumor Ablation Therapy" by X Ding et al. will be at 4:00 p.m. on Wednesday, July 21 in room 204B of the Philadelphia Convention Center.
MORE MEETING INFORMATION
AAPM is the premier organization in medical physics, a broadly-based scientific and professional discipline encompassing physics principles and applications in medicine and biology. Its membership includes medical physicists who specialize in research that develops cutting-edge technologies and board-certified clinical medical physicists who apply these technologies in community hospitals, clinics, and academic medical centers.
The presentations at the AAPM meeting will cover topics ranging from new ways of imaging the human body to the latest clinical developments on treating cancer with high energy X-rays and electrons from accelerators, brachytherapy with radioactive sources, and protons. Many of the talks and posters are focused on patient safety -- tailoring therapy to the specific needs of people undergoing treatment, such as shaping emissions to conform to tumors, or finding ways to image children safely at lower radiation exposures while maintaining good image quality.
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ABOUT MEDICAL PHYSICISTS
If you ever had a mammogram, an ultrasound, an X-ray, CT, MRI or a PET scan, a medical physicist was working behind the scenes to make sure the imaging procedure was as effective as possible. Medical physicists are involved in the development of new imaging techniques, improve existing ones, and assure the safety of radiation used in medical procedures in radiology, radiation oncology and nuclear medicine. They collaborate with radiation oncologists to design cancer treatment plans. They provide routine quality assurance and quality control on radiation equipment and procedures to ensure that cancer patients receive the prescribed dose of radiation to the correct location. They also contribute to the development of physics intensive therapeutic techniques, such as the stereotactic radiosurgery and prostate seed implants for cancer to name a few. The annual AAPM meeting is a great resource, providing guidance to physicists to implement the latest and greatest technology in a community hospital close to you.
The AAPM is a scientific, educational, and professional nonprofit organization whose mission is to advance the science, education and professional practice of medical physics. The Association encourages innovative research and development, helps disseminate scientific and technical information, fosters the education and professional development of medical physicists, and promotes the highest quality medical services for patients. Please visit the Association Web site at http://www.