A balloon-shaped gantry (21) to rotate longitudinally and latitudinally at least one source of external radiation concentrically around an isocenter arranged on a target to be irradiated, balloon-shaped gantry that has a central ej 5 e that crosses the isocentro and comprising the following components: (i) a front opening ring (22) with its origin on the central axis of the balloon-shaped gantry, (ii) at least one support arm of the arc-shaped gantry (23 ), which has a front end and a rear end and is part of a circle, (iii) an external radiation source (24), which is mounted on the at least one arc-shaped gantry support arm (23) and can move along the arc-shaped gantry support arm (23) to make latitudinal rotation around the isocenter, (iv) a rear rotation axis (25) with an axis along the central axis of the gantry balloon-shaped, (v) a base of sopo rte (27), and (vi) a rear housing (26) comprising a power supply, mechanisms for moving globe-shaped gantry components and controllers to control the movement of globe-shaped gantry components and irradiation of the target in the patient, in which the front opening ring (22) is attached to the front end of the at least one support arm of the arc-shaped gantry (23), in which the rear rotation axis (25 ) is attached to the rear end of the at least one support arm of the arc-shaped gantry (23), in which the front opening ring (22) and the rear rotation axis (25) are supported by the support base (27) and the rear housing (26), and in which the front opening ring (22) and the rear rotation axis (25) can rotate around the central axis causing the external radiation source to rotate longitudinally.Un pórtico en forma de globo (21) para girar longitudinalmente y latitudinalmente al menos una fuente de radiación externa concéntricamente alrededor de un isocentro dispuesto en una diana que va a irradiarse, pórtico en forma de globo que tiene un ej 5 e central que cruza el isocentro y que comprende los siguientes componentes: (i)
