What is the role of dynamic intrafractional assessment in image-guided radiotherapy (IGRT) for the treatment of prostate cancer?

Updated: Nov 29, 2018
  • Author: Isamettin Andrew Aral, MD, MS; Chief Editor: Edward David Kim, MD, FACS  more...
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Answer

As increasing information regarding the potential for interfractional organ movement has become available, concerns about this possibility have grown accordingly. This issue is particularly important because many intensity-modulated radiation treatments can require 20-30 minutes or longer.

Of the devices listed above, only radiofrequency-based localization has been regularly used to obtain information about target localization during the course of linear accelerator–based radiotherapy. Newer generations of radiation-based equipment (eg, robotic arm linear accelerator–based therapy and the CyberKnife [Accuray, Sunnyvale, CA]) have unique treatment repositioning techniques that are not found in association with linear accelerator–based therapy.

The use of radiofrequency transponders can be valuable as each treatment fraction is administered. After initial patient positioning using this image-guided technique, any potential target movement can be accurately tracked during treatment. In the simplest of models, when a discordance is detected between the expected location and the actual location, the machine can be stopped from delivering further radiotherapy.

In a more complicated system, the patient can be automatically repositioned to correct for the measured change in target localization. Because this technology is relatively new, phase 3, multi-institutional studies of overall benefit are still under way. [22, 23]


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