A combined MRI and radiation therapy system has MRI imaging equipment and radiation therapy equipment. The MRI imaging equipment includes a shielded solenoidal magnet including a number of main magnet coils arranged coaxially along an axis, and a shielding arrangement arranged coaxially with the axis, at a greater radius from the axis than the main magnet coils. The radiation therapy equipment includes a LINAC assembly, that includes a linear electron accelerator arranged with an electron beam path parallel to the axis, and electron beam deflection arrangement and a target for generating a beam of therapeutic radiation. The linear electron accelerator is located at a position radially between the main magnet coils and the shielding arrangement.