A radiation treatment apparatus, comprising: a gantry frame; a rotatable gantry structure rotatably coupled to said gantry frame, said rotatable gantry structure being rotatable around a rotation axis passing through an isocenter; said rotatable gantry structure including a first beam member extending between first and second ends of said rotatable gantry structure; characterized in that the radiation treatment apparatus further comprises: a radiation treatment head movably mounted to said first beam member in a manner that allows (i) translation of the radiation treatment head along said first beam member between said first and second ends, and (ii) gimballing of the radiation treatment head relative to said first beam member, said gimballing being characterized by pivotable movement in at least two independent pivot directions defined with respect to said first beam member; and an imaging system comprising an imaging source mounted on a second beam member and an imaging detector mounted on a third beam member, wherein said imaging source is movably mounted to said second beam member in a manner that allows (i) translation of the imaging source along said second beam member and (ii) pivoting of the image source relative to said second beam member around at least one pivot axis, the second and third beam member being distal from said rotation axis and being mounted to at least one of the rotatable gantry structure or an additional rotatable gantry structure rotatably coupled to said gantry frame, said additional rotatable gantry structure being rotatable around said rotation axis concentrically with, and independently of, said rotatable gantry structure; whereby non-coplanar radiation treatment of a tissue volume positioned near or around said isocenter is achievable. a gantry frame; a rotatable gantry structure rotatably coupled to said gantry frame, said rotatable gantry structure being rotatable around a rotation axis passing through an isocenter; said rotatable gantry structure including a first beam member extending between first and second ends of said rotatable gantry structure; characterized in that the radiation treatment apparatus further comprises: a radiation treatment head movably mounted to said first beam member in a manner that allows (i) translation of the radiation treatment head along said first beam member between said first and second ends, and (ii) gimballing of the radiation treatment head relative to said first beam member, said gimballing being characterized by pivotable movement in at least two independent pivot directions defined with respect to said first beam member; and an imaging system comprising an imaging source mounted on a second beam member and an imaging detector mounted on a third beam member, wherein said imaging source is movably mounted to said second beam member in a manner that allows (i) translation of the imaging source along said second beam member and (ii) pivoting of the image source relative to said second beam member around at least one pivot axis, the second and third beam member being distal from said rotation axis and being mounted to at least one of the rotatable gantry structure or an additional rotatable gantry structure rotatably coupled to said gantry frame, said additional rotatable gantry structure being rotatable around said rotation axis concentrically with, and independently of, said rotatable gantry structure; whereby non-coplanar radiation treatment of a tissue volume positioned near or around said isocenter is achievable. a radiation treatment head movably mounted to said first beam member in a manner that allows (i) translation of the radiation treatment head along said first beam member between said first and second ends, and (ii) gimballing of the radiation treatment head relative to said first beam member, said gimballing being characterized by pivotable movement in at least two independent pivot directions defined with respect to said first beam member; and an imaging system comprising an imaging source mounted on a second beam member and an imaging detector mounted on a third beam member, wherein said imaging source is movably mounted to said second beam member in a manner that allows (i) translation of the imaging source along said second beam member and (ii) pivoting of the image source relative to said second beam member around at least one pivot axis, the second and third beam member being distal from said rotation axis and being mounted to at least one of the rotatable gantry structure or an additional rotatable gantry structure rotatably coupled to said gantry frame, said additional rotatable gantry structure being rotatable around said rotation axis concentrically with, and independently of, said rotatable gantry structure; whereby non-coplanar radiation treatment of a tissue volume positioned near or around said isocenter is achievable.