Detection and measurement of respiration using optical cameras and projected shadows

Abstract

A respiration monitoring device comprising: a light source (30) arranged to generate a projected shadow (S) of an imaging object (P) positioned for imaging by an imaging device (8); a camera (40) arranged to acquire video of the projected shadow; and an electronic processor (42) programmed to extract the position of the edge of the projected shadow as a function of time from the acquired video. In some embodiments, the light source is arranged to project shadows onto the bore wall (20) of the imaging device, and the camera is arranged to capture video of the projected shadow on the bore wall. The electronic processor may be programmed to extract the position of the edge (E) as a one-dimensional function of time (46) based on the position of the edge in each frame of the acquired video and the timestamp of the video frame.

Description

technical field [0001] The following generally relates to the field of medical imaging, the field of respiratory monitoring, the field of respiratory-gated medical imaging, and related fields. Background technique [0002] Monitoring of patient breathing during medical imaging can serve a variety of useful purposes. The monitored breathing cycle can be used to perform prospective gated imaging, wherein imaging data is only collected during certain parts (ie phases) of the breathing cycle, which can reduce motion artifacts due to breathing. In an alternative retrospective gating method, imaging data is collected continuously and then binned by respiratory phase, and selected phases can be reconstructed. Respiration monitoring can also be used to detect breath holding, eg to trigger imaging when a patient holds his or her breath. Respiration monitoring can also serve patient safety monitoring functions, eg, an imaging session can be interrupted or terminated if breathing bec...

AI Technical Summary

Problems solved by technology

Difficulties with this approach include the placement of the camera, which typically views the patient unobstructed from above, and the complex image processing performed to extract chest motion

This method is also prone to errors due to small patient / camera misalignment, and / or due to low image contrast, e.g. if the patient is wearing an all-white hospital gown; and if the patient is lying in a supine position such that the chest cannot be viewed, and / or May not be available if the chest is covered by obscured components such as local radio frequency (RF) coils (as in some MR imaging procedures)

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