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HOUSTON MEETING HIGHLIGHTS: Physics and the Future of Medicine
American Association of Physicists in Medicine Meeting, July 27 to July 31


The risk that exposure to stray radiation during cancer therapy will cause secondary malignancies is small -- it should never deter one from following one's doctor's advice and undergoing radiation therapy for the treatment of cancer. Nevertheless, stray radiation as a potential side effect should always be minimized, and a team of researchers at M.D. Anderson Cancer Center is exploring ways to reduce stray radiation, and the risk it brings, by modifying the radiation delivery machine.

A recent study examined whether stray radiation was reduced by removing the flattening filter from a standard radiation machine. Currently, the flattening filter is included in all standard radiation machines to ensure uniformity of the radiation beam. However, with current technology, optimal treatments for most radiation machines does not require a uniform beam, rendering the flattening filter completely unnecessary for the majority of radiation treatments. In this case, it may be advantageous to remove it from the radiation machine as it is a source of stray radiation.

This study, one of many undertaken by this group in the last four years, found that there were a large number of patients (particularly those with small tumors) who could benefit from treatment with a radiation machine without the flattening filter. Such equipment would produce less stray radiation, corresponding to a decreased risk of developing a second cancer later in life. In addition to reduced stray radiation, several other benefits to the patient and hospital staff exist such as potentially improved treatments, faster treatment delivery, and less stray radiation to medical personnel.

Modification of traditional radiation equipment will require collaboration with machine manufacturers, and while the logistics of removing the flattening filter are not particularly challenging, what will be more challenging is ensuring that the modified machine remain safe for patient treatments. When the flattening filter is removed, the built-in double checks and triple checks that assure patient safety must be redesigned or at least re-evaluated to ensure they still rigorously ensure safety for people undergoing treatment. This work is a step in reducing stray radiation for patients with small tumors, however, methods to further reduce stray radiation, and thereby further reduce the risk of secondary cancers, will continue to be a priority.

Talk (TH-D-AUD A-5), "Dose Outside the Treatment Volume Following Removal of the Flattening Filter" is at 1:18 p.m. on Thursday, July 31 in Auditorium A. Contact: S. Kry (sfkry@mdanderson.org). Abstract: http://www.aapm.org/meetings/amos2/pdf/35-8297-12719-983.pdf





Reporters who would like to attend the meeting in person should fill out the press registration form on the AAPM Virtual Press Room. See: http://www.aapm.org/meetings/08AM/VirtualPressRoom/documents/pressregform.pdf.

Reporters who would like to cover the conference remotely will find releases and articles on the Virtual Press Room highlighting many of the interesting and important talks presented at the meeting. Even if you can't make it to Houston, the Virtual Press Room will make it possible to write stories about the meeting from your desk.


The American Association of Physicists in Medicine (AAPM) is a scientific, educational, and professional nonprofit organization whose mission is to advance the application of physics to the diagnosis and treatment of human disease. 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. In 2008, AAPM will celebrate its 50th year of serving patients, physicians, and physicists. Please visit the association's Web site at http://www.aapm.org/.


Headquartered in College Park, MD., the American Institute of Physics is a not-for-profit membership corporation chartered in New York State in 1931 for the purpose of promoting the advancement and diffusion of the knowledge of physics and its application to human welfare.


Media contacts:

Jason Socrates Bardi, American Institute of Physics,
301-209-3091 (office) 858-775-4080 (cell)

Jeff Limmer, AAPM Media Relations Subcommittee Chair