Distinctive features


CT scan ( MVCT ) is taken before each fraction to check correct patientí s position


If necessary, patientís position can be automatically re-adjusted compared with treatment plan conditions


Accurate dose distribution by helical delivery of radiation beam



Specific features


X6 MV photon radiation source


Binary multileaf collimator


CT detector with ion chambers (xenon)


Rotating movement of radiation source and CT detectors


Longitudinally moving couch for data collecting/treatment


Side, vertical, longitudinalmovements of the couch for adjustments


Treatment planning: inverse planning





Tomotherapy is an equipment conceived for radiation treatment where the radiation source, modulated through a binary multileaf collimator, rotates in unison with a CT computed tomography around the couch in a continuous longitudinal movement.



Before each fraction, a CT scan is taken ( MVCT, Tomoimage: Fig. 1 ) that is compared to the reference image ( kVCT, Reference Image: Fig. 2 ) according to which the treatment plan has been worked out.





Fig. 1 MVCT ( TomoImage )


Fig. 2kVCT ( Reference Image )


Tomotherapy software allows the two CT images to be recorded together ( Correlated Images: Fig. 3 ), pointing out necessary adjustment to assure correctposition of patient.



If necessary, patientís position is automatically adjusted and treatment is executed: radiation source turns around the couch that moves lengthwise in unison, while the dose is helically delivered. Dose delivery is extremely accurate: different disease sites can be treated one at a time ( ex. prostate, head and neck) or more than one during the same treatment (ex. Lung , Total Body Irradiation ) sparing healthy tissues.