News | April 21, 2009

Tomotherapy Shows Prostate Motion Affects Target Dose Only Slightly

April 21, 2009 – In a study in which researchers from the MD Anderson Cancer Centre Orlando, FL, and the University of Wisconsin, Madison, conducted an analysis of prostate motion during helical tomotherapy, they concluded that the impact on target dose is actually quite small (Int. J. Rad. Oncol. Biol. Phys. doi: 10.1016/j.ijrobp.2008.09.035).

The study marked the first time that helical tomotherapy has been considered in similar detail. Researchers used electromagnetic markers by Calypso Medical Technologies to track prostate motion. Three markers were implanted under ultrasound guidance in 16 patients who went on to receive IMRT. Tomotherapy treatment plans were generated retrospectively and compared with motion tracks from the markers.

Two separate scenarios were considered. The first assumed that treatment started at the beginning of the observation period. The second anticipated an estimated delay of five minutes between patient alignment and the start of treatment. The minimum dose (Dmin), maximum dose (Dmax) and dose to 95 percent of the volume (D95 percent) were calculated for the whole prostate and for the planning target volume (PTV). These values were then compared with the doses that would have been delivered had the prostate stayed still. The cumulative effect was also evaluated over the course of treatment.

The results showed that for individual fractions, target D95 percent could be reduced by as much as 20 percent. However, the effect of such sizeable dose reductions diminished quickly as treatment continued. The effect on target D95 percent was less than 1 percent by the time that five fractions had been delivered. The biggest surprise was the similarity in observed changes to D95 percent for the prostate and the PTV.

While the results only apply to whole-prostate tomotherapy, researchers will test other techniques that may be affected more by organ motion, such as dose-painting, in a follow-up study.

For more information:

Related Content

First Hospitals Achieve Inter-System Connectivity Across Accuray Radiation Therapy Platforms
News | Radiation Therapy | January 19, 2018
Accuray Inc. announced recently that the Heidelberg University Hospital in Heidelberg, Germany, and Oscar Lambret...
RayStation Selected for New Carbon Ion Therapy Center in Japan
News | Treatment Planning | January 18, 2018
January 18, 2018 – RayStation has been chosen as the treatment planning system for a new carbon-ion therapy facility
Raysearch Receives First Order for the Raycare Oncology Information System
News | Oncology Information Management Systems (OIMS) | January 18, 2018
January 18, 2018 – Anderson Regional Cancer Center (ARCC) in Meridian, Mississippi, has placed the first order for...
Mevion Receives 510(k) Clearance for Hyperscan Pencil Beam Scanning Proton Therapy
Technology | Proton Therapy | January 04, 2018
Mevion Medical Systems has received U.S. Food and Drug Administration (FDA) 510(k) clearance for the Mevion S250i...
Study Compares Radiosurgery and Whole-Brain Radiation in Lung Cancer Patients With Multiple Brain Metastases
News | Radiation Therapy | January 03, 2018
Although targeted therapies have produced dramatic advances in the ability to control some types of advanced lung...
MEDraysintell Downgrades Proton Therapy Market Projection for 2030
News | Proton Therapy | January 02, 2018
MEDraysintell recently downgraded its projection for proton therapy rooms expected to be operational in 2030 from 1,200...
California US Oncology Network Centers Adopt Xoft Electronic Brachytherapy System for Early-Stage Non-Melanoma Skin Cancer
News | Brachytherapy Systems | January 02, 2018
iCAD Inc. announced that its Xoft Axxent Electronic Brachytherapy (eBx) System is now available at two California-based...
Blue Phantom System Used for Acceptance of First European Varian Halcyon Machine
News | Radiation Therapy | January 02, 2018
IBA (Ion Beam Applications S.A.) announced in November the acceptance and beam model validation of the first Varian...
Study Finds Link Between Breast Cancer Treatments and Cellular Aging Markers
News | Women's Health | January 02, 2018
January 2, 2018 — A new study found women who had received chemotherapy and/or...
ACR Appropriateness Criteria Adds and Revises Topics for December 2017
News | Clinical Decision Support | December 29, 2017
December 29, 2017 — Radiologists can enhance the quality and effectiveness of care with the newest release of the ACR
Overlay Init