Acceptance testing and commissioning of Radixact™ X9 tomotherapy unit: initial experience

Helical Tomotherapy is recognized as modern solution for radiotherapy to sculpture highly conformal dose to the target and minimal toxicity to OARs. A 6 MV linear accelerator is mounted on a ring gantry for image-guided intensity-modulated radiation therapy treatment. The major advantage of Radixact™ X9 system from its predecessor is that it offers increased dose rate of about 1000 cGy/min at isocenter and 10 rpm gantry rotation for faster image acquisition with reduced imaging dose rate. Like CT technology, gantry rotation and couch longitudinal translation are simultaneous that permits helical dose distribution up to 135 cm treatment length. A fan beam created by the collimator and jaws produces a maximum of 40 X 5 Cm² field size at the isocenter. The linac can be operated at a lower voltage (3.5 MV) to produce CT images, which are used for patient image verifications. Radixact™ X9 tomotherapy unit was commissioned for clinical use at our center in June 2018