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Combined Imaging System Could Reduce Radiotherapy Errors

Technique for real-time 3D tumor localization may improve radiotherapy accuracy.

Janelle Weaver, Contributor
Wednesday, November 21, 2018


Respiratory motion of our lungs during radiotherapy is a major cause for surrounding healthy tissues to be exposed to unnecessary radiation. Localizing lung tumors in real time has been intensively investigated for managing respiratory motion to ensure tumor coverage while reducing unnecessary radiation exposure.

In a study published Oct. 25 in Medical Physics, researchers demonstrated that a combined megavoltage/kilovoltage (MV/kV) imaging system can provide real-time 3D localization of lung tumors. The researchers simultaneously collected tumor motion traces via an electromagnetic tracking system and MV/kV radiographic images during radiotherapy of two lung cancer patients, who had three electromagnetic beacon transponders implanted in airways near the lung tumors. 

The combined MV/kV imaging system showed comparable accuracy to the electromagnetic-based system. According to the authors, the demonstrated 3D localization accuracy of 2 millimeters would not cause significant dosimetric errors in tumor coverage, so the technique has the potential to be incorporated into clinical operations in the future.