n. a frameless stereotactic radiotherapy system produced from a small *linear accelerator, which has a robotic arm that allows the beam to be directed from any direction, and which monitors movement of implanted markers to deliver real-time *image-guided radiotherapy.
(IGRT) the process of imaging during a course of radiation treatment to verify the internal position of the target in comparison to the initial planning scan. This enables adjustment of *treatment fields to improve coverage and allows the use of smaller treatment volumes. The possible methods for IGRT include cone beam CT, *tomotherapy, *cyberknife, and ultrasound and kilovoltage X-rays of implanted fiducial markers.... image-guided radiotherapy
the accurate localization, with the help of scans, of structures within the body by using three-dimensional measurements. It enables the accurate positioning within the body of radiotherapy beams or sources for the treatment of tumours and of localizing wires for the biopsy of small tumours. See also stereotaxy; cyberknife; gamma knife.... stereotactic localization
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