Tomotherapy

Abstract

Helical TomoTherapy® is an integrated software and hardware platform for image-guided intensity modulated radiotherapy (IMRT). Serial TomoTherapy was one of the first systems that showed the feasibility of IMRT delivery by delivering concave isodose distributions that matched the calculated dose distribution. The dose calculation used in TomoTherapy planning systems was a collapsed cone convolution/superposition initially developed by T. Rock Mackie et al. and used in the Pinnacle planning system. TomoTherapy dose to the target natively tends to be highly homogenous. The dynamic jaw mode, trademarked as TomoEdge, starts and ends a treatment with 1-cm jaw but increases the jaw opening to the user-selected maximal jaw size of either 2.5-cm or 5-cm in between. TomoTherapy uses constant rotational periods for the entire treatment and the gantry rotational period is determined by the longest leaf opening time. TomoTherapy utilizes the same x-ray target for both imaging and therapy.