News | July 28, 2008

Targeting Specific Tumor Regions Alters Treatment Plans

July 29, 2008 - Not all parts of a tumor respond to radiation therapy in the same way.

Treatments in the future may target the most resistant tumor regions, but measuring this resistance is far from straightforward, a new analysis shows.

Common radiation therapy prescribes a uniform radiation dose to the entire tumor, even though it is commonly known that some regions resist radiation more than others. Researchers are therefore experimenting with ways to tailor the treatment, with so-called "dose painting," so that more radiation falls on the radio-resistant parts.

For this to be effective, radio-resistance must be well-defined at the molecular level. This presumably can be done with PET scans using the radio-tracer FLT (fluoro-L-thymidine). When injected into the body, FLT is grabbed up by cells in the process of cell division. Therefore, rapidly-dividing cancer cells will look bright in a PET scan. Once treatment is started, those cells that remain bright would be considered radio-resistant (i.e. the radiation is not affecting their activity.) But this simple brightness measure, called a standardized uptake value (SUV), is not the only way to locate non-responsive cells in a PET image. A more precise way (based on a parameter called KFLT) is to model how the radio-tracer travels through the body and is taken up by cells over time.

Urban Simoncic of the Institut Jozef Stefan in Ljubljana, Slovenia, together with collaborators from University of Wisconsin-Madison compared the SUV and KFLT techniques on the exact same sets of PET scans and found that the two selected out different regions as being radio-resistant. This implies that a dose painting treatment based on one model would differ significantly from that based on the other. The researchers believe the community needs to address this discrepancy with more careful clinical investigation.

For more information: www.aapm.org

Source: American Association of Physicists in Medicine

Related Content

Insightec Announces Expanded Reach of MR-Guided Focused Ultrasound
News | Focused Ultrasound Therapy | August 22, 2017
Insightec announced recently that worldwide adoption of magnetic resonance (MR)-guided focused ultrasound continues to...
UCLA Study Offers Roadmap to Personalized Therapies for Sarcoma
News | Oncology Diagnostics | August 22, 2017
A new UCLA study is the first to identify patient and tumor characteristics that predict the successful creation of...
Sponsored Content | Videos | Information Technology | August 22, 2017
Melissa Martin, MS, president of the American Association of Physicists in Medicine (AAPM), discusses her vision of t
Sponsored Content | Videos | Proton Therapy | August 21, 2017
Mark Pankuch, Ph.D., director of medical physics at the Northwestern Medicine Chicago Proton Center, discusses the cl
Summit Cancer Center-Boise Treats First Cancer Patients With Accuray Radixact System
News | Image Guided Radiation Therapy (IGRT) | August 21, 2017
Accuray Inc. and the Summit Cancer Center-Boise announced that the center is now treating patients with the Radixact...
MedStar Georgetown Proton Center Selects RayStation for Treatment Planning
News | Treatment Planning | August 17, 2017
August 17, 2017 — The proton center at MedStar Georgetown University Hospital will utilize RayStation for planning on
DOSIsoft Releases ISOgray Proton Therapy Treatment Planning System
Technology | Treatment Planning | August 15, 2017
DOSIsoft SA announced the official release, with CE marking, of ISOgray Treatment Planning System (TPS) release 4.3 for...
First Radixact Results Presented at AAPM 2017
News | Radiation Therapy | August 10, 2017
Accuray Inc. announced that the first studies validating the benefits of the Radixact System were presented at the 59th...
Clinical Data Supports Use of Xoft System for Endometrial Cancer
News | Brachytherapy Systems | August 03, 2017
Researchers presented clinical data supporting use of the Xoft Axxent Electronic Brachytherapy (eBx) System for the...
Overlay Init