Tracking Soft Tissue in Medical Images

Abstract

The present disclosure is directed to a system, method and apparatus for tracking an anatomical body part in a series of x-ray images. The anatomical body part moves due to a vital movement, such as breathing motion of the thorax. The anatomical body part is defined in a CT image acquired beforehand and is associated with a known movement phase during the vital movement. The series of x-ray images of the moving anatomical body part is taken. The movement phase associated with each one of the x-ray images is determined. In one implementation, the system may track the body part movement using external infrared-reflecting markers and a navigation system while taking a series of x-ray images and time-stamping the x-ray images and the positional information for the body part. The time stamps relate each one of the x-ray images with a specific movement phase of the body part. The specific x-ray image being associated with the same movement phase as the CT image is determined and the representation of the anatomical body part defined in the CT image can be determined in the x-ray image by comparing the CT image with the specific x-ray image. The specific x-ray image may be compared to the other x-ray images to find the anatomical body part in those x-ray images and preferably highlight it to be easily recognized by a user.

1 .- 15 . (canceled) 
     
     
         16 . A system, comprising a computer having a processor configured to execute a computer-implemented method of determining the representation of an anatomical body part of a patient in a sequence of medical images, the anatomical body part being subject to a vital movement of the patient, the method comprising executing, on the processor of the computer, steps of:
 acquiring, at the processor, advance medical image data comprising a time-related advance medical image having a representation of the anatomical body part in a specific movement phase;   acquiring, at the processor, current medical image data describing a sequence of current medical images, wherein the sequence comprises a specific current medical image comprising a representation of the anatomical body part in the specific movement phase, and a tracking current medical image which is different from the specific current medical image and comprises a representation of the anatomical body part in a tracking movement phase which is different from the specific movement phase;   determining, by the processor and based on the advance medical image data and the current medical image data, specific image subset data describing a specific image subset of the specific current medical image, the specific image subset comprising the representation of the anatomical body part;   determining, by the processor and based on the current medical image data and the specific image subset data, subset tracking data describing a tracked image subset in the tracking current medical image, the tracked image subset comprising the representation of the anatomical body part.   
     
     
         17 . A computer-implemented method of determining the representation of an anatomical body part of a patient in a sequence of medical images, the anatomical body part being subject to a vital movement of the patient, the method comprising executing, on a processor of the computer, steps of:
 acquiring, at the processor, advance medical image data comprising a time-related advance medical image comprising a representation of the anatomical body part in a specific movement phase;   acquiring, at the processor, current medical image data describing a sequence of current medical images, wherein the sequence comprises a specific current medical image comprising a representation of the anatomical body part in the specific movement phase, and a tracking current medical image which is different from the specific current medical image and comprises a representation of the anatomical body part in a tracking movement phase which is different from the specific movement phase;   determining, by the processor and based on the advance medical image data and the current medical image data, specific image subset data describing a specific image subset of the specific current medical image, the specific image subset comprising the representation of the anatomical body part;   determining, by the processor and based on the current medical image data and the specific image subset data, subset tracking data describing a tracked image subset in the tracking current medical image, the tracked image subset comprising the representation of the anatomical body part.   
     
     
         18 . The method according to  claim 17 , comprising a step of acquiring, at the processor, current movement phase data describing a current movement phase of the anatomical body part in the states in which it is described by the sequence of current medical images,
 wherein the current movement phase data is generated based on acquiring digital signals describing the vital movement which have been generated based on tracking marker devices attached to the patient's body and correlating the result of the tracking with the current medical image data,   wherein the specific current medical image is determined, by the processor, based on the current movement phase data.   
     
     
         19 . The method according to  claim 17 , wherein the specific image subset data describes the position of the specific image subset in the specific current medical image, and wherein the subset tracking data describes the position of the tracked image subset in the tracking current medical image. 
     
     
         20 . The method according to  claim 19 , comprising a step of determining, by the processor and based on the current medical image data and the subset tracking data and the current movement phase data, internal breathing curve data describing a time-correlation of the image positions of the anatomical body part and the sequence of current medical images. 
     
     
         21 . The method according to  claim 17 , wherein the specific image subset data is determined, by the processor, based on determining, by the processor, a corresponding representation of the anatomical body part in the advance medical image and in the sequence of current medical images. 
     
     
         22 . The method according to  claim 21 , comprising a step of acquiring, at the processor, current medical image user input data describing an input by a user for selecting the specific image subset from the specific current medical image wherein the image subset data is determined, by the processor, based on the user input data. 
     
     
         23 . The method according to  claim 17 , comprising a step of acquiring, at the processor, advance image subset data describing an advance image subset of the advance medical image comprising the representation of the anatomical body part, wherein the specific image subset data is determined, by the processor, based on the advance image subset data. 
     
     
         24 . The method according to  claim 23 , comprising a step of acquiring, at the processor, advance medical image user input data describing an input by a user for selecting the advance image subset from the advance medical image, wherein the advance image subset data is determined, by the processor, based on the advance medical image user input data. 
     
     
         25 . The method according to  claim 23 , wherein the advance image subset data is determined based on automatic determination of the advance image subset, for example by applying an image segmentation algorithm to the advance medical image. 
     
     
         26 . The method according to  claim 22 , wherein the specific image subset data is determined, by the processor, based on the result of comparing the advance image subset data to the specific current medical image. 
     
     
         27 . The method according to  claim 17 , wherein the subset tracking data is determined by determining, by the processor, a region in the tracking current medical image which is at least to a predetermined degree comparable to the specific image subset. 
     
     
         28 . The method according to  claim 17 , wherein the advance medical image data has been generated by applying a computed tomography imaging method to the patient's body, wherein the advance medical image is a digitally rendered radiograph rendered from the computed tomography of the patient's body, and wherein the sequence of current medical images has been generated by applying a conventional x-ray imaging method. 
     
     
         29 . A non-transitory computer-readable program storage medium storing a program, which, when executed on a processor of a computer or when loaded into a memory of the computer, causes the computer to perform a computer-implemented method of determining the representation of an anatomical body part of a patient in a sequence of medical images, the anatomical body part being subject to a vital movement of the patient, the method comprising executing, on the processor of the computer, steps of:
 acquiring, at the processor, advance medical image data comprising a time-related advance medical image comprising a representation of the anatomical body part in a specific movement phase;   acquiring, at the processor, current medical image data describing a sequence of current medical images, wherein the sequence comprises a specific current medical image comprising a representation of the anatomical body part in the specific movement phase, and a tracking current medical image which is different from the specific current medical image and comprises a representation of the anatomical body part in a tracking movement phase which is different from the specific movement phase;   determining, by the processor and based on the advance medical image data and the current medical image data, specific image subset data describing a specific image subset of the specific current medical image, the specific image subset comprising the representation of the anatomical body part;   determining, by the processor and based on the current medical image data and the specific image subset data, subset tracking data describing a tracked image subset in the tracking current medical image, the tracked image subset comprising the representation of the anatomical body part.   
     
     
         30 . A treatment device, comprising:
 a computer having a memory and instructions stored thereon, the instructions, when executed by one or more processors of the computer, causing the computer to determine the representation of an anatomical body part of a patient in a sequence of medical images, the anatomical body part being subject to a vital movement of the patient, the computer, when executing the instructions, further implements the steps of:   acquiring, at the processor, advance medical image data comprising a time-related advance medical image comprising a representation of the anatomical body part in a specific movement phase;   acquiring, at the processor, current medical image data describing a sequence of current medical images, wherein the sequence comprises a specific current medical image comprising a representation of the anatomical body part in the specific movement phase, and a tracking current medical image which is different from the specific current medical image and comprises a representation of the anatomical body part in a tracking movement phase which is different from the specific movement phase;   determining, by the processor and based on the advance medical image data and the current medical image data, specific image subset data describing a specific image subset of the specific current medical image, the specific image subset comprising the representation of the anatomical body part;   determining, by the processor and based on the current medical image data and the specific image subset data, subset tracking data describing a tracked image subset in the tracking current medical image, the tracked image subset comprising the representation of the anatomical body part.   a medical imaging device for acquiring the current medical image data;   an irradiation unit for emitting a treatment beam to the patient's body,   wherein the computer is operatively coupled to the medical imaging device to acquire the current medical image data and to the irradiation unit to issue control signals for emitting the treatment beam.