Tomotherapy: A new concept for the delivery of dynamic conformal radiotherapy

TLDR

Tomotherapy proposes delivering radiation therapy using intensity‑modulated strips of radiation, offering a new approach to conformal treatment planning and verification. It employs a linear accelerator mounted on a ring gantry that rotates while the patient traverses the bore, with temporally modulated multileaf collimator leaves controlling intensity, and the gantry also accommodates a detector and CT scanner. The system achieves highly conformal radiation delivery with treatment times comparable to current techniques, and its physical properties and design specifications have been evaluated and justified.

Abstract

Tomotherapy, literally "slice therapy," is a proposal for the delivery of radiation therapy with intensity-modulated strips of radiation. The proposed method employs a linear accelerator, or another radiation-emitting device, which would be mounted on a ring gantry like a CT scanner. The patient would move through the bore of the gantry simultaneously with gantry rotation. The intensity modulation would be performed by temporally modulated multiple independent leaves that open and close across the slit opening. At any given time, any leaf would be (1) closed, covering a portion of the slit, (2) open, allowing radiation through, or (3) changing between these states. This method would result in the delivery of highly conformal radiation. Overall treatment times should be comparable with contemporary treatment delivery times. The ring gantry would make it convenient to mount a narrow multisegmented megavoltage detector system for beam verification and a CT scanner on the treatment unit. Such a treatment unit could become a powerful tool for treatment planning, conformal treatment, and verification using tomographic images. The physical properties of this treatment delivery are evaluated and the fundamental design specifications are justified.