An emitter comprising - only one radiological filter designed for being passed through by an x-ray beam; said radiological filter comprising o a longitudinal axis; o a first working surface; o a second working surface placed opposite said first working surface in relation to said radiological filter so as to enable said x-ray beam to pass through said radiological filter entering said radiological filter and leaving said radiological filter through said working surfaces (1b, 1c); o a first sector defining a first portion of said first working surface, which is flat, o a second sector defining a second portion of said first working surface that is curved and complementary to said first portion in relation to said first working surface, and said sectors (2, 3) extend substantially parallel to said longitudinal axis; - a source designed to emit an x-ray beam hitting said first working surface; and - a handler implementing relative motion between said radiological filter and said x-ray beam by defining o a first operating condition wherein said x-ray beam hits exclusively said first portion and o a second operating condition wherein said x-ray beam hits at least said second portion. - only one radiological filter designed for being passed through by an x-ray beam; said radiological filter comprising o a longitudinal axis; o a first working surface; o a second working surface placed opposite said first working surface in relation to said radiological filter so as to enable said x-ray beam to pass through said radiological filter entering said radiological filter and leaving said radiological filter through said working surfaces (1b, 1c); o a first sector defining a first portion of said first working surface, which is flat, o a second sector defining a second portion of said first working surface that is curved and complementary to said first portion in relation to said first working surface, and said sectors (2, 3) extend substantially parallel to said longitudinal axis; o a longitudinal axis; o a first working surface; o a second working surface placed opposite said first working surface in relation to said radiological filter so as to enable said x-ray beam to pass through said radiological filter entering said radiological filter and leaving said radiological filter through said working surfaces (1b, 1c); o a first sector defining a first portion of said first working surface, which is flat, o a second sector defining a second portion of said first working surface that is curved and complementary to said first portion in relation to said first working surface, and said sectors (2, 3) extend substantially parallel to said longitudinal axis; - a source designed to emit an x-ray beam hitting said first working surface; and - a handler implementing relative motion between said radiological filter and said x-ray beam by defining o a first operating condition wherein said x-ray beam hits exclusively said first portion and o a second operating condition wherein said x-ray beam hits at least said second portion. o a first operating condition wherein said x-ray beam hits exclusively said first portion and o a second operating condition wherein said x-ray beam hits at least said second portion.