A patient motion monitoring system (102) for use in a proton therapy center
(100) is disclosed. The patient monitoring system (102) includes a
plurality of position detector assemblies (162) with each position
detector assembly (162) being constructed of a flexibly rigid support arm
(132) attached to a position sensor (130). Each support arm (132) of the
plurality of position detector assemblies (162) is detachably mounted to a
supporting structure so as to allow the corresponding position sensor
(130) to be positioned adjacent a patient (104) who is receiving proton
therapy. Furthermore, each position sensor (130) of the plurality of
position detector assemblies (162) generates a position signal that is
indicative of the distance between a front surface of the position sensor,
and an adjacent surface of the patient. The patient motion monitoring
system (102) further includes a controller (160) which is adapted to
receive each position signal from the plurality of position detector
assemblies (162), a display (144), and an alarm (148) to indicate if a
patient has moved out of position.
