Image guided radiation therapy apparatus

摘要

An image guided radiation therapy (IGRT) apparatus comprising a medical imaging device such as an MRI (1, figure 1) integrated with a linear accelerator. The radiation beam from the linac can be shaped by a beam shaper (8, figure 1) which may be a multi-leaf collimator (MLC). The position of the beam shaper is adjustable between a first position and a second position, wherein the first position is a treatment position and the second position is a maintenance position removed from the gantry (2, figures 1 & 3) of the IGRT apparatus. The beam shaper is mounted on an adjustment arm 18 having a mechanical arm 10, an actuator 14 and a housing 12 which contains an MLC having a leaf driving section 13 and multiple leaf section 17. The arm is pivotally attached to the gantry through a bore 16 or via a multi-axis joint and may be lockable in the treatment position. The arm may include a linear actuator and further joints. A light source on the IGRT apparatus may project a light beam through the beam shaper in the second position.