Featured Research

from universities, journals, and other organizations

New Advance In Radiation Therapy May Improve Cancer Treatment

Date:
July 26, 2000
Source:
American Institute of Physics -- Inside Science News Service
Summary:
Radiation therapy has long been a tool in the ongoing battle against cancer. But the therapy can harm healthy tissue that surrounds tumors. Now, medical physicists have found a method for delivering radiation that allows physicians to hit tumors without hurting surrounding tissue.

CHICAGO, IL (July 19, 2000)-- Radiation therapy - the treatment of disease with penetrating beams of particles such as x-rays - has long been a primary weapon in the war on cancer. That's because x-rays and other forms of radiation can readily destroy tumors by depositing energy on them. But radiation can also harm healthy tissue, for the very same reason. At an international conference in Chicago next week, medical physicists will discuss what many see as a significant advance in radiation therapy. Known as intensity modulated radiotherapy (IMRT), the new technique enables physicians to deliver greater amounts of radiation to the precise location of a tumor while minimizing the dose to the healthy tissue that surrounds it. Researchers are hopeful that IMRT will improve treatment of many cancers.

Until recently, radiation therapy has employed beams of nearly uniform intensity or with rudimentary devices for modifying the intensity. As a result, there were some instances in which the desired dose of radiation could not be delivered to the entire tumor without harming healthy tissue in the process.

IMRT solves this problem by allowing the intensity of each radiation beam to be varied or "modulated." In other words, each beam can send out a sophisticated radiation pattern that varies in time and space. Firing non-uniform beams from several angles could deliver the desired dose to the tumor while minimizing doses to surrounding organs.

IMRT is currently being used at several locations, such as the Memorial Sloan-Kettering Cancer Center in New York City and the Washington University School of Medicine in St. Louis. Researchers expect the technique to spread rapidly to many medical centers in the coming months and years. As a possible indicator of its potential importance, the technique will be featured at the upcoming World Congress on Medical Physics and Biomedical Engineering, co-sponsored by the American Association of Physicists in Medicine. To take place in Chicago from July 23-28, the meeting will have a two-day series of invited lectures on IMRT and over 100 additional contributed presentations on the new technique.

"In so many situations, you would like to send a larger dose of radiation to a tumor, but you can't because it would damage other organs," says Raj Varadahn, a medical physicist at Minneapolis Radiation Oncology, a cancer treatment center in Minnesota. "IMRT is a significant advance in maximizing the radiation dose to tumors and minimizing the dose to healthy tissues that surround it," he says.

The new technique could potentially improve radiation therapy in all forms of cancer. In prostate cancer, for example, doctors could send larger radiation doses to a prostate tumor, while minimizing doses to surrounding organs such as the rectum and bladder. Early results from clinical trials have indicated that increasing the radiation dose to prostate tumors improves the chances of surviving past five years with that cancer. In some cancers of the head and neck, IMRT can deliver more radiation to the tumor while minimizing doses to the sensitive organs such as the parotid glands, which regulate the flow of saliva. In preliminary data, researchers at the Washington University School of Medicine have found that patients receiving IMRT radiation therapy have better saliva function compared to those who receive traditional radiation therapy. "It's currently the low-dose sensitive structures in which IMRT is particularly useful," says Washington University medical physicist Daniel Low, an internationally known IMRT authority who is organizing the two-day lecture series on the new technique at the upcoming Chicago Meeting.

Acquiring precise, three-dimensional images of the body is the first step that made IMRT possible. Using techniques such as CT scans and magnetic resonance imaging, scientists can now obtain precise, 3-dimensional images of tumors inside the body. This helps physicians know the exact location of the tumor--and where to direct tumor-destroying radiation beams.

In the last decade, researchers developed the ability to get a "beam's eye view" of a tumor. In other words, researchers can determine the exact dose that a radiation beam delivers to a particular tumor. With this information, physicians can send an exact dose of radiation to thethree-dimensional region where a tumor resides.

Perhaps the greatest breakthrough enabling IMRT is the development, by medical physicists, of powerful computer programs, or "algorithms," to determine the right combination of beam angles and intensities that will do the best job of providing the desired dose. These algorithms work backwards: physicians can assign radiation dose limits to both the tumors and sensitive nearby organs, and then get a computer to generate the instructions for how to deliver that dose.

Medical physicists view this "inverse planning" approach as a major advance in cancer treatment. Previously, researchers could only use a trial-and-error-based "forward planning" approach, in which they would first select beam angles and intensities, observe the results, and make the appropriate modifications to approach the desired dose.

What's also vital to the IMRT approach is the hardware, and there are several ingenious systems for modifying the intensity of the beam. In one technique, researchers can split a single beam into hundreds of thin beams--each with a different intensity. In another approach, the radiation beam passes through a special opening known as a multi-leaf collimator (MLC). Made of tungsten plates that can be arranged under computer control, the MLC can change shape from moment to moment to vary the shape and intensity of the beam which passes through. Finally, University of Wisconsin researchers have built a special radiation delivery device that can deliver radiation in a helix-shaped spiral to the body. Combined with MLCs, the helical delivery system may allow for more effective 3D coverage of the tumor.

Medical physicists see IMRT as an effective cancer-treatment tool for the dawn of the 21st century--and possibly beyond.

# # #

WEBSITES:

IMRT explanation at Nomos Corporation
http://www.nomos.com/dwhat.html

Intensity Modulated Radiation Therapy
http://www.brachytherapy.com/IMRT.html

World Congress on Medical Physics and Biomedical Engineering
http://www.wc2000.org

EXPERT CONTACTS:
Daniel A. Low
Washington University at St. Louis School of Medicine
(314) 362-2636
LOW@CASTOR.WUSTL.EDU

Eric E. Klein
Washington University at St. Louis School of Medicine
(314) 454-7740
klein_ee@castor.wustl.edu


Story Source:

The above story is based on materials provided by American Institute of Physics -- Inside Science News Service. Note: Materials may be edited for content and length.


Cite This Page:

American Institute of Physics -- Inside Science News Service. "New Advance In Radiation Therapy May Improve Cancer Treatment." ScienceDaily. ScienceDaily, 26 July 2000. <www.sciencedaily.com/releases/2000/07/000719151922.htm>.
American Institute of Physics -- Inside Science News Service. (2000, July 26). New Advance In Radiation Therapy May Improve Cancer Treatment. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2000/07/000719151922.htm
American Institute of Physics -- Inside Science News Service. "New Advance In Radiation Therapy May Improve Cancer Treatment." ScienceDaily. www.sciencedaily.com/releases/2000/07/000719151922.htm (accessed July 25, 2014).

Share This




More Matter & Energy News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

TSA Administrator on Politics and Flight Bans

TSA Administrator on Politics and Flight Bans

AP (July 24, 2014) TSA administrator, John Pistole's took part in the Aspen Security Forum 2014, where he answered questions on lifting of the ban on flights into Israel's Tel Aviv airport and whether politics played a role in lifting the ban. (July 24) Video provided by AP
Powered by NewsLook.com
Creative Makeovers for Ugly Cellphone Towers

Creative Makeovers for Ugly Cellphone Towers

AP (July 24, 2014) Mobile phone companies and communities across the country are going to new lengths to disguise those unsightly cellphone towers. From a church bell tower to a flagpole, even a pencil, some towers are trying to make a point. (July 24) Video provided by AP
Powered by NewsLook.com
Algonquin Power Goes Activist on Its Target Gas Natural

Algonquin Power Goes Activist on Its Target Gas Natural

TheStreet (July 23, 2014) When The Deal's Amanda Levin exclusively reported that Gas Natural had been talking to potential suitors, the Ohio company responded with a flat denial, claiming its board had not talked to anyone about a possible sale. Lo and behold, Canadian utility Algonquin Power and Utilities not only had approached the company, but it did it three times. Its last offer was for $13 per share as Gas Natural's was trading at a 60-day moving average of about $12.50 per share. Now Algonquin, which has a 4.9% stake in Gas Natural, has taken its case to shareholders, calling on them to back its proposals or, possibly, a change in the target's board. Video provided by TheStreet
Powered by NewsLook.com
Robot Parking Valet Creates Stress-Free Travel

Robot Parking Valet Creates Stress-Free Travel

AP (July 23, 2014) 'Ray' the robotic parking valet at Dusseldorf Airport in Germany lets travelers to avoid the hassle of finding a parking spot before heading to the check-in desk. (July 23) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

    Health News

      Environment News

        Technology News



          Save/Print:
          Share:

          Free Subscriptions


          Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

          Get Social & Mobile


          Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

          Have Feedback?


          Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
          Mobile: iPhone Android Web
          Follow: Facebook Twitter Google+
          Subscribe: RSS Feeds Email Newsletters
          Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins