Distinctive features

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

If necessary, patient’s 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, longitudinal movements of the couch for adjustments

Treatment planning: inverse planning

TOMOTHERAPY FEATURES

		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. 2 kVCT ( Reference Image )
		Tomotherapy software allows the two CT images to be recorded together ( Correlated Images: Fig. 3 ), pointing out necessary adjustment to assure correct position of patient.
		If necessary, patient’s 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.