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 ; 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 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 ; 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 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 ; 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 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 . <EOS>