July 29, 2008 - People facing bone marrow transplants have a series of challenges to surmount.
One of the first is the total destruction by radiation of their bone marrow in a process called total body irradiation. This preconditions the person’s body to accept the new marrow as treatment for cancers of the blood and immune system.
Preconditioning may one day be improved if a feasibility study by a group of Chicago-area researchers is validated in further studies. In experiments using a specialized manikin-like form that is the radiological equivalent of the human body, 98 percent of the intended structures received 99 percent of prescribed radiation dose, while normal body structures were spared from high doses.
"Compared to conventional total body irradiation, this new approach reduced radiation to critical body parts such as the heart and the lungs by as much as 64 percent and 30 percent respectively which is a distinct improvement," says lead researcher Bulent Aydogan, Ph.D. of the University of Chicago.
Collaborators include researchers from the University of Illinois/Chicago and Loyola University Medical Center.
The new technique is called linac-based Intensity Modulated Total Marrow Irradiation. “Linac” refers to the linear particle accelerator used to deliver precisely planned doses of radiation to the body. Rather than dosing the entire body equally, it selectively targets bone marrow locations and administers lower radiation doses to the rest of the body.
Such accuracy is made possible by first mapping the patient’s body in 3D using a sophisticated computer scan. Next, computer programs optimize each beam of radiation into smaller “beamlets” so that each beam is individually suited to meet planned dosing goals for a given site.
Finally, a linear particle accelerator (linac) delivers these planned doses to the patient. Radiation is therefore limited to bone marrow and cancerous structures, thus sparing critical organs in the body. If further evidence supports these early findings, the team hopes to move this new treatment to clinical trials involving humans.
For more information: www.aapm.org
Source: American Association of Physicists in Medicine
July 25, 2024 
