Device for generating trigger signals for a medical apparatus dependent on the respiratory activity of a patient

Claim 1

A medical diagnostic apparatus comprising: a spirometer having a channel therein adapted to be traversed by the respiratory air of a patient, a turbine having a plurality of blades and being rotatably mounted in said channel so as to be rotated by respiratory air; opto-electrical transducer means disposed in said spirometer and having a light path modulatable by rotation of said turbine blades for generating an electrical signal at a point in the respiratory cycle of the patient dependent on the rotation of said turbine and thus on the flow of respiratory air in said channel; first computer means to which said electrical signal is supplied for generating a trigger signal at said point in the respiratory cycle and including means for setting a respiratory trigger threshold to select said point in said respiratory cycle; a computer tomography imaging system connected to said first computer means, said computer tomography imaging system including means for conducting a scan of a patient consisting of a plurality of exposures of said patient respectively triggered by said trigger signal and for generating scan data during each exposure, and also including second computer means for constructing an image of the scanned region of said patient from said scan data, said first computer means including means for generating and supplying a signal to said second computer means in said computer tomography imaging system for marking respiratory activity at said point in said respiratory cycle within said scan data; and said spirometer also including means disposed in said channel connected to and operable by said first computer means for completely blocking inspiration and expiration in said channel when said respiratory trigger threshold is reached.