X-ray imaging apparatus having vibration stabilising means, and method for operating such an X-ray imaging apparatus

An X-ray imaging apparatus comprising:

• an imaging assembly mounted on a rotary arm;
• an X-ray source and an X-ray detector coupled to the rotary arm so that X-rays emitted by the X-ray source are incidental to the X-ray detector;
• a first vibration measurement device coupled to the X-ray source and a second vibration measurement device coupled to the X-ray detector;
• a first actuator and a second actuator configured to move the X-ray source and the X-ray detector to suppress at least one component of vibrations measured by the first and second vibration measurement devices;
• and
• a vibration controller configured to receive vibration level measurements from the first and second vibration measurement devices, to generate first and second control signals based on the vibration level measurements, and to send the first and second control signals to the first and second actuators, wherein the vibration controller is configured to generate the first and second control signals to minimize the following function:
• Δ
• ⁢
• ⁢
• i
• =
• (
• Act
• d
• +
• F
• 2
• +
• F
• 1
• )
• +
• (
• Act
• t
• +
• F
• 3
• +
• F
• 1
• )
• ⁢
• P
• d
• -
• P
• t
• P
• p
• -
• P
• t
• (
• 1
• )
• wherein:
• Δi corresponds to image variation due to the vibrations;
• Actd represents a difference of position between the X-ray detector and the second actuator;
• F1 corresponds to the position of a knuckle of the rotary arm;
• F2 corresponds to a difference of position between the second actuator and the knuckle of the rotary arm;
• Actt represents a difference of position between the X-ray source and the first actuator;
• F3 represents a difference of position between the first actuator and the knuckle of the rotary arm;
• Pd corresponds to the position of the X-ray detector;
• Pt corresponds to the position of the X-ray source;
• and
• Pp corresponds to the position of a patient body to be imaged.

A method for operating an X-ray imaging apparatus comprising an imaging assembly mounted on a rotary arm, an X-ray source and an X-ray detector coupled to the rotary arm so that X-rays emitted by the X-ray source are incidental to the X-ray detector, a first vibration measurement device coupled to the X-ray source, a second vibration measurement device coupled to the X-ray detector, a first and second piezoelectric actuator configured to move the X-ray source and the X-ray detector to suppress at least one component of vibrations measured by the first and second vibration measurement devices, and a vibration controller, the method comprising:

• measuring vibration levels in the X-ray source and in the X-ray detector;
• generating, with the vibration controller, first and second control signals based on the measured vibration levels;
• sending the first and second control signals to the first and second piezoelectric actuators;
• and
• modifying a thickness of the first and second piezoelectric actuators to move the X-ray source and the X-ray detector to suppress at least one component of the vibration levels.