Patent ID: 12232865

The figures are schematic only and not true to scale. In principle, identical or like parts, elements and/or steps are provided with identical or like reference symbols in the figures.

DESCRIPTION OF EMBODIMENTS

FIG.1shows a flow chart illustrating the basic steps of the computer-implemented medical method of determining a breathing signal202and/or a breathing curve200(seeFIG.4) of a patient100(seeFIG.3) according to an exemplary embodiment and/or according to the first aspect.

Step S1comprises determining a motion trajectory120(seeFIG.3) of a structure104(seeFIG.3) associated with at least one body part of the patient100, wherein the motion trajectory120is indicative of a respiratory movement of the structure104and/or the at least one body part.

Therein, step S1may comprise retrieving the motion trajectory120and/or trajectory data indicative of the motion trajectory120from a data storage. Accordingly, the motion trajectory120may be pre-defined.

Alternatively or additionally, the motion trajectory120may be determined based on structure data51(seeFIG.3), as will be described in more detail with reference toFIGS.2to4.

Optionally, in step S1a motion axis110indicative of the respiratory movement of at least a part of the structure104can be determined and/or defined based on the motion trajectory. The motion axis110may be a vertical or non-vertical axis with respect to a vertical axis130(seeFIG.3) of the patient100parallel to an anterior-posterior direction. Particularly, the motion axis110may take into account a respiratory movement of the structure104in anterior-posterior and in cranial-caudal direction of the patient100. For example, the motion axis110and the vertical axis130of the patient100may enclose an angle of about 35° to about 55°, preferably about 40° to about 50°. The angle may, for example, be measured in a plane of a longitudinal axis and the vertical axis130of the patient100.

In step S2, surface data50(seeFIG.3), such as e.g. image data, representative of a position of a surface region106of the patient100in space, e.g. at time instant during the breathing motion, are acquired. Optionally, this may comprise capturing the surface data50, e.g. with a surface camera and/or any other type of device capable of capturing surface data50describing and/or containing information about the position of the surface region106in space.

In step S3, an intersection (in space) of the determined motion trajectory120and the acquired surface data50(and/or the surface region106represented by the surface data) is calculated. Optionally, intersection data descriptive of the intersection may be determined in step S3.

Based on the intersection, a breathing signal202(seeFIG.4) of the patient100is determined in step S4, which can represent a breathing amplitude, a breathing state, a depth of inspiration and/or a breathing activity of the patient100at a specific time and/or time instant.

As indicated by the arrow inFIG.1, steps S2to S4can be iteratively repeated, thereby allowing to determine a sequence of temporally successive breathing signals202and/or a breathing curve200of the patient100.

FIG.2shows a flowchart illustrating steps of a method of determining a breathing signal202(seeFIG.4) of a patient100according to an exemplary embodiment of the invention. If not stated otherwise, steps S1to S4ofFIG.2are identical to steps S1to S4described with reference toFIG.1.FIG.3illustrates some steps of the method according toFIGS.1and2.FIG.4illustrates a breathing signal202and/or a breathing curve200determined based on the method ofFIGS.1and2.

Specifically,FIG.3illustrates structure data51as well as surface data50, as used in the context of the present disclosure. Accordingly, in the example depicted inFIG.3, both the structure data51and the surface data50are of the same data type and exemplary acquired by means of a surface camera. It should be noted, however, that the structure data51can be of different type compared to the surface data50. Hence, the structure data51and the surface data50can be captured with different means. Specifically, the structure data51and the surface data50can be captured with any one or more of a surface camera, a thermal camera, a marker device, a medical imaging device, and a breathing detector, as described in the summary part of the present disclosure.

Further, it should be noted that in the example shown inFIG.3, the structure104associated with the at least one body part of the patient100, for which the motion trajectory120is determined in step S1, refers to at least a part of the surface region106that is intersected with the motion trajectory120in step S3. Alternatively, any other structure106that moves in accordance with a breathing motion of the patient100can be used, which may differ from the surface region106. Generally, the surface region106and/or the structure104may refer to an arbitrary area or region of interest, based on which the breathing signal202is determined. Further, the at least one body part in the example ofFIG.3can, for instance, refer to the patient's torso and/or the surface region106.

InFIG.2, the determination of the motion trajectory120is exemplary further illustrated by optional steps S1ato S1c. The motion trajectory120may, for instance, be determined in a learning phase.

In step S1a, at least two temporally successive structure data51and/or a sequence of structure data51is acquired. Each of the acquired structure data51is representative of a position of at least a part of the structure104in space, e.g. at a certain time and/or time instant.

In step S1b, trajectory data indicative of a trajectory108along which at least a part of the structure104moves and/or is displaced in the sequence of structure data51is determined. Optionally, this may comprise tracking the structure104and/or the position thereof, e.g. such that the trajectory data may be given as two-dimensional or three-dimensional spatial coordinates as a function time. As shown inFIG.3, the trajectory108of the structure104and/or at least a part thereof may be hysteresis like and/or elliptically. Any other trajectory108, however, is conceivable. The trajectory data may be indicative of the trajectory108in two or three spatial directions. In other words, the trajectory data may be two-dimensional or three-dimensional trajectory data. For instance, the (actual) trajectory108may be projected into a plane held by a longitudinal axis and the vertical axis130of the patient100to generate two-dimensional trajectory data.

Further, in step S1c, a motion axis110is determined based on the trajectory data and/or the trajectory108. The motion axis110can accurately approximate the movement and/or displacement of the structure104caused by the breathing of the patient100. As shown inFIG.3, the motion axis110is tilted in cranial-caudal direction with respect to a vertical axis130of the patient and/or transverse to the cranial-caudal direction, thereby allowing to precisely approximate the respiratory movement of the structure104.

The motion axis110may enclose an angle132(of e.g. about 30° to 50°) with the vertical axis130along the cranial-caudal direction of the patient100and/or parallel to the longitudinal axis of the patient. Hence, the motion axis110may lay in the plane held by the longitudinal axis and the vertical axis130of the patient100. Also, the motion axis110may be skew with respect to the vertical axis130, i.e. it may be tilted in cranial-caudal (or longitudinal) direction and transverse thereto.

Generally, the motion axis110may describe one or more movement components related to one or more spatial directions the structure104is displaced during breathing. Particularly, the motion axis110may refer to a main motion axis110′ indicative of a main movement component of the respiratory movement of the structure104. For instance, the main motion axis110′ may be determined in step S1cbased on the trajectory data using principal component analysis. For instance, the main motion axis110′ may be defined by the first principal component (optionally also the second and/or third principal component) as determined based on analysing the trajectory data using PCA, as described in detail in the summary part of the present disclosure.

Further, the motion trajectory120of the structure104may be determined in step S1cbased on the determined motion axis110and/or the determined main motion axis110′. In this context, the motion trajectory120may be defined by and/or may be given by the motion axis110and/or the main motion axis110′.

Once the motion trajectory120is determined, the method ofFIG.2can continue with steps S2to S4as described with reference toFIG.1. By iteratively repeating steps S2to S4, a sequence of surface data50over time is acquired, a sequence of intersections is computed over time, and a sequence of breathing signals202is determined over time. Therein, the breathing signal202over time allows determining and/or provides a breathing curve200as exemplary shown inFIG.4. Specifically,FIG.4shows the breathing curve200as a breathing amplitude in arbitrary units as a function of time in arbitrary units. A point on the breathing curve200represents the breathing signal202, which may be given as a breathing amplitude A at a time t.

Further,FIG.4illustrates a breathing cycle204, which corresponds to a part of the breathing curve200covering one breathing period (and/or a respiratory cycle), e.g. between two consecutive maxima as shown inFIG.4. It should be noted that the sequence of structure data51acquired in step S1amay preferably cover a complete breathing cycle204, although this may not be required to accurately determine the breathing signal202.

FIG.5shows schematically a medical system500according to an exemplary embodiment of the invention and/or according to the fifth aspect. The system is in its entirety identified by reference numeral500and comprises a computer502, an electronic data storage device (such as a hard disc)504for storing at least the surface data50, and a medical device506, e.g. for carrying out a medical procedure, particularly an irradiation treatment. The components of the medical system500have the functionalities and properties explained above and in the following with regard to the fifth and/or any other aspect of the present disclosure. Particularly, the at least one computer502is operably coupled to the at least one electronic data storage504device for acquiring, from the at least one data storage device504, at least the surface data50. The system500may further comprise a surface camera508for capturing the structure data51and/or the surface data50.

Further, computer502is coupled to the medical device506for issuing a control signal to the medical device506for controlling the operation of the medical device506on the basis of the breathing signal202, as described above and in the following.

The medical system500and/or the medical device506of the system500comprises a radiation treatment apparatus510comprising a treatment beam source512and a patient support unit514, wherein the at least one computer502is operably coupled to the radiation treatment apparatus510for issuing a control signal to the radiation treatment apparatus510for controlling, on the basis of the breathing signal202, at least one of the operation of the treatment beam source512and the position of the patient support unit514.

While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art and practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.