Modelling and simulation of a respiratory motion monitor using a continuous wave Doppler radar in near field

Abstract

To avoid motion artifacts in medical imaging or to minimize exposure of healthy tissues in radiation therapy medical devices are often synchronized with the patient’s respiration. Today’s respiratory motion monitors require additional effort in preparing the patient, such as mounting of a motion belt or the placement of an optical reflector on the patient breast, and they are not able to measure internal organ motion without implanting markers. An interesting alternative to assess the person’s respiratory motion is a continuous wave Doppler radar. By placing the antennas close to the body, the radar waves propagate into the body and are reflected on boundaries between body tissues, for example between muscle and adipose tissue or on the outline of organs. To evaluate the radar system, a macroscopic simulation model is created to study the radar measurement process of human beings. To check the theoretical considerations of the model, measurements performed by a robot are used. Simulation of human respiratory motion is done by using computed tomography (CT) datasets, reconstructed at different respiratory phases.