Method and system for steerable medical device path definition and following during insertion and retraction

Abstract

Waypoints for a steerable medical device are stored as the steerable medical device is moved within a patient. The stored waypoints are an ordered sequence of locations. The ordered sequence of locations defines a safe path within the patient for moving an articulatable portion of the steerable medical device. The articulatable portion of the steerable medical device is constrained to follow the safe path as the articulatable portion moves within the patient. For example, the articulatable portion of the steerable medical device is constrained to remain within a boundary region enclosing the safe path as the articulatable portion of the steerable medical device follows the safe path.

1 . A method comprising:
 storing waypoints of a steerable medical device, wherein said stored waypoints comprise an ordered sequence of locations, and further wherein said ordered sequence of locations defines a safe path for moving an articulatable portion of said steerable medical device within a patient;   constraining said articulatable portion of said steerable medical device to follow said safe path as said articulatable portion moves within said patient.   
   
   
       2 . The method of  claim 1  wherein said constraining further comprises:
 constraining said articulatable portion of said steerable medical device to remain within a boundary region enclosing said safe path as said articulatable portion of said steerable medical device follows said safe path.   
   
   
       3 . The method of  claim 2  wherein said boundary region comprises a tube having a cross-section. 
   
   
       4 . The method of  claim 3  wherein said cross-section comprises one of a circular cross-section, an oblate cross-section, and a rectangular cross cross-section. 
   
   
       5 . The method of  claim 2  wherein said articulatable portion is included in a plurality of segments of said steerable medical device. 
   
   
       6 . The method of  claim 5  wherein said constraining said articulatable portion of said steerable medical device to remain within a boundary region enclosing said safe path further comprises:
 generating position and orientation data for each of said plurality of segments using said ordered sequence of locations and a kinematic model of said plurality of segments of said steerable medical device.   
   
   
       7 . The method of  claim 6  wherein said generating further comprises:
 minimizing a cost function to generate said position and orientation data for each of said plurality of segments.   
   
   
       8 . The method of  claim 7  wherein said minimizing a cost function further comprises:
 minimizing the sum of the absolute values of relative joint angles, with an additional constraint that link positions not deviate by more than a distance Δ at each of the waypoints in said ordered sequence of locations.   
   
   
       9 . The method of  claim 1  wherein said articulatable portion of said steerable medical device comprises a segment of said steerable medical device and said segment comprises a plurality of links. 
   
   
       10 . An apparatus comprising:
 a steerable medical device having an articulatable portion; and   a controller, coupled to said steerable medical device, comprising:
 a processor; 
 a memory coupled to said processor; and 
 a medical device controller coupled to said processor and to said steerable medical device; and
 wherein said processor stores in said memory an ordered sequence of locations; and 
 said processor analyzes said ordered sequence of locations and outputs to said medical device controller at least one command to constrain said articulatable portion within a boundary region enclosing a safe path defined by said ordered sequence of locations. 
 
   
   
   
       11 . The apparatus of  claim 10  wherein said articulatable portion of said steerable medical device comprises a segment of said steerable medical device and said segment comprises a plurality of links. 
   
   
       12 . The apparatus of  claim 10  wherein said boundary region comprises a tube having a cross-section. 
   
   
       13 . The apparatus of  claim 12  wherein said cross-section comprises one of a circular cross-section, an oblate cross-section, and a square cross cross-section.