WARF: P150044US01

Soft-Spectrum Filter for External Beam Radiation Therapy


Bhudatt Paliwal, Yue Yan

The Wisconsin Alumni Research Foundation (WARF) is seeking commercial partners interested in developing SPECTER, a radiation filter to spare healthy tissue from soft-spectrum scatter.
OVERVIEWIn conventional external beam radiation therapy, also called teletherapy, a linear accelerator (LINAC) is used to deliver a radiation beam to a target region inside a patient. The radiation is delivered from several different directions, or beam paths. Together, the determination of how much dose to deliver along each beam path constitutes the treatment plan.

Flattening filters (FF) have been included as a component of LINAC systems for several decades to ensure the quality of the radiation beam. More recently, flattening-filter-free (FFF) systems have been studied and implemented. FFF beams offer several advantages such as higher dose rate, rapid modulation and shorter treatment time.

However, one major disadvantage is that the low energy photons (‘soft spectrum’) of the FFF beam may increase the amount of radiation scatter inside a patient’s body, putting healthy tissue and organs at risk.
THE INVENTIONUW–Madison researchers have developed a new soft-spectrum filter called SPECTER that uses beam-filtering material to block the unwanted soft portion of an FFF radiation beam. The high energy ‘hard spectrum’ of the beam can pass unfiltered through a central aperture.

The material and dimensions of the SPECTER may be optimized to control external radiation scatter and loss in high dose rates compared with other system employing FFF beams.
  • Implementation in external beam radiation therapy systems
  • Suitable systems include image-guided radiation therapy (IGRT), intensity-modulated radiation therapy (IMRT), intensity-modulated arc therapy (IMAT), volumetric arc therapy (VMAT) and tomotherapy systems
  • Could improve the survival rate of patients
  • Reduces internal scatter dose
  • Helps protect organs at risk (OARs) and other surrounding tissue
  • May be used to maintain a higher dose rate
Contact Information
For current licensing status, please contact Jeanine Burmania at or 608-960-9846.
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