Motion synchronized arc radiotherapy

Patent metadata

Field	Value
Publication number	US-12239852-B2
Application number	US-201917309457-A
Country	US
Kind code	B2
Filing date	Nov 28, 2019
Priority date	Nov 28, 2018
Publication date	Mar 4, 2025
Grant date	Mar 4, 2025

Abstract

Apparatus and methods for planning and/or delivering radiation treatment and controlling a radiation delivery system are described. Apparatus for delivering radiation treatment includes a radiation source, a drive connected to move the radiation source along a trajectory, a stored radiation treatment plan specifying a plurality of beam ON segments and beam OFF portions of the trajectory interleaved with the plurality of beam ON segments, and a monitor connected to detect progress of a physiological cycle of the patient, the physiological cycle has cycles that include quiescent periods. One or more data processors are connected to control the drive to advance the radiation source along the trajectory, control the radiation source to deliver radiation in each of the plurality of beam ON segments of the trajectory and to deliver no or negligible radiation in each of the beam OFF portions of the trajectory, process an output of the monitor to estimate a time for a next one of the quiescent periods, and control a speed at which the radiation source is advanced along the trajectory to cause the radiation source to arrive at a start of a next one of the beam ON segments at a time that coincides with the next one of the quiescent periods.

First claim

What is claimed is:

1. An apparatus for delivering a radiation treatment to a patient, the apparatus comprising:
a radiation source;
a drive connected to move the radiation source along a trajectory relative to the patient;
a memory having stored therein a radiation treatment plan specifying a plurality of beam ON segments of the trajectory and specifying a plurality of beam OFF portions of the trajectory interleaved with the plurality of beam ON segments of the trajectory;
a patient monitoring system connected to monitor a cardiac cycle of the patient, wherein the cardiac cycle includes quiescent periods;
one or more data processors connected to:
control the drive to advance the radiation source along the trajectory;
control the radiation source to deliver radiation in each of the plurality of beam ON segments of the trajectory and to deliver no or negligible radiation in each of the plurality of beam OFF portions of the trajectory;
process an output of the patient monitoring system to estimate a time for a next one of the quiescent periods of the cardiac cycle; and
control a speed at which the radiation source is advanced along the trajectory to cause a next one of the plurality of beam ON segments to coincide with the next one of the quiescent periods of the cardiac cycle.

2. The apparatus according to claim 1 , wherein the patient monitoring system comprises an electrocardiogram (ECG) system.

3. The apparatus according to claim 2 , wherein the one or more data processors are configured to:
receive an ECG trace from the patient monitoring system;
process the ECG trace to identify points, where a rate of change of the ECG trace exceeds a threshold;
within a window around each of the identified points of the ECG trace locate an R peak as a maximum of the ECG trace within the window;
determine a time difference between two most recent adjacent R peaks as a period of the cardiac signal and determine the estimated time for a next one of the quiescent periods based on the determined time difference between the two most recent adjacent R peaks.

4. The apparatus according to claim 1 , wherein the patient monitoring system comprises one or more of: a real-time imager; a pulse monitor; or an impedance-based monitor.

5. The apparatus according to claim 1 , wherein the patient monitoring system comprises a real-time imager, the apparatus further comprising an image processor that includes a model trained to locate metallic cardiac leads in images obtained by the real-time imager and to process locations of the metallic cardiac leads determined by the model to determine motions of the metallic cardiac leads.

6. The apparatus according to claim 1 , wherein each of the plurality of beam OFF portions of the trajectory is about twice as long as each of the plurality of beam ON segments of the trajectory.

7. The apparatus according to claim 1 , wherein:
the radiation treatment plan comprises a plurality of phases;
the one or more data processors are configured to execute the plurality of phases in a sequence;
each of the plurality of phases specifies a subset of the plurality of beam ON segments of the trajectory and a subset of the plurality of beam OFF portions of the trajectory; and
subsets of the plurality of beam ON segments in different ones of the plurality of phases are at different locations along the trajectory.

8. The apparatus according to claim 7 , wherein subsets of the plurality of beam ON segments in different phases overlap by a length corresponding to a ramp up time for the radiation source.

9. The apparatus according to claim 7 , wherein the plurality of phases comprises three phases, and subsets of the plurality of beam ON segments from the three phases collectively cover the trajectory.

10. The apparatus according to claim 1 , further comprising:
a data store connected to record the output of the patient monitoring system, wherein:
the one or more data processors are configured to process the output of the patient monitoring system to estimate a time for a next one of the quiescent periods by processing most recent data in the data store; and
the one or more data processors are configured to determine a cardiac cycle period from the most recent data in the data store, and to estimate the time for a next one of the quiescent periods based in part on the determined cardiac cycle period; or
the one or more data processors are configured to determine a time derivative of a cardiac cycle period from the most recent data in the data store, and to estimate the time for a next one of the quiescent periods based in part on the determined time derivative of the cardiac cycle period.

11. The apparatus according to claim 1 , wherein the one or more data processors are configured to advance the radiation source along the trajectory without stopping until at least the end of a last one of the plurality of beam ON segments.

12. The apparatus according to claim 1 , further comprising:
a gantry,
wherein the radiation source is mounted to the gantry which is rotatable about an axis, the trajectory comprises an arc made by the radiation source as the gantry is rotated between a starting angle and an ending angle, and the one or more data processors are configured to maintain an average acceleration of the gantry to not exceed 0.15 deg/s 2 between a start of a first beam ON segment in the trajectory and the end of a last beam ON segment in the trajectory.

13. The apparatus according to claim 1 , further comprising:
a variable beam shaper,
wherein the radiation treatment plan comprises parameters specifying configurations of the variable beam shaper at least for points along the trajectory in the plurality of beam ON segments, and the one or more data processors are configured to adjust a speed with which the variable beam shaper is varied among the configurations to match the speed at which the radiation source is advanced along the trajectory.

14. The apparatus according to claim 1 , wherein the plurality of beam ON segments have lengths such that each beam ON segment can be delivered in a time not exceeding about 200 ms at a speed that does not exceed a maximum speed at which the drive can advance the radiation source along the trajectory.

15. The apparatus according to claim 1 , wherein the one or more data processors are configured to receive a preliminary radiation treatment plan, and to segment the preliminary radiation treatment plan to provide the radiation treatment plan.

16. A method for controlling a position of a radiation source of a radiation delivery system along a trajectory, the method comprising:
reading a radiation treatment plan specifying locations along the trajectory of a plurality of beam ON segments and a plurality of beam OFF portions interleaved between the plurality of beam ON segments;
processing an output of a patient monitoring system configured to monitor a cardiac cycle of the patient to estimate a starting time for starting a next one of the plurality of beam ON segments such that the next one of the plurality of beam ON segments will coincide with a quiescent period of the cardiac cycle; and
adjusting a speed at which the radiation source is being driven along the trajectory to cause the radiation source to arrive at a location along the trajectory corresponding to the next one of the plurality of beam ON segments at the starting time.

17. The method according to claim 16 , wherein the output of the patient monitoring system comprises an electrocardiogram (ECG) trace, and the method further comprises:
processing the EC

Assignees

• Provincial Health Services Authority

Inventors

• Thomas Steven
• Kohli Kirpal
• Poon Justin Jeremy Jeun-Ming

Classifications

• A61N5/1045

  using a multi-leaf collimator, e.g. for intensity modulated radiation therapy or IMRT · CPC title

• A61N2005/1055

  using magnetic resonance imaging [MRI] · CPC title

• A61N5/1047

  with movement of the radiation head during application of radiation, e.g. for intensity modulated arc therapy or IMAT · CPC title

• A61N5/1037

  taking into account the movement of the target, e.g. 4D-image based planning · CPC title

• A61N2005/1061

  using an x-ray imaging system having a separate imaging source · CPC title