CHARACTERIZING AND MAPPING OF A MAGNETIC FIELD OF A MEDICAL DEVICE

1 . A computing device for representing, with a computer model, a magnetic field generated by a magnetic field source of a magnetic-field-based medical device, comprising:

an input interface for receiving a plurality of magnetic field measurement entries of said magnetic field;

a processor; and

memory storing program code that, when executed by said processor, causes said processor to:

receive a theoretical three-dimensional model of said magnetic field generated by said magnetic field source;

receive, via said input interface, said plurality of magnetic field measurement entries, wherein each magnetic field measurement entry of said plurality of magnetic field measurement entries comprises an amplitude value of said magnetic field and a corresponding positional coordinate;

estimate errors of amplitude between default amplitude values of said theoretical three-dimensional model and corresponding said amplitude values of said plurality of magnetic field measurement entries based on said positional coordinates of said plurality of magnetic field measurement entries; and

adjust default values of said theoretical three-dimensional model based on said estimated errors of amplitude, resulting in a real-world three-dimensional magnetic field model from said theoretical three-dimensional model with adjusted amplitude values, whereby said real-world three-dimensional magnetic field model comprises a constellation of adjusted amplitude values in a space representative of said magnetic field generated by said magnetic field source.

2 . The computing device of claim 1 , wherein said estimating comprises calculating a difference between said default values of said magnetic field of said theoretical model and said amplitude values of said magnetic field of said plurality of magnetic field measurement entries through an interpolation method.

3 . The computing device of claim 2 , wherein said adjusting is based on a Kriging interpolation method.

4 . The computing device of any one of claims 1 to 3 , further comprising said medical device.

5 . The computing device of any one of claims 1 to 4 , wherein said input data further comprises a value of orientation of said magnetic field, and wherein said estimating errors of amplitude further uses said value of orientation of each of said correlated said input data.

6 . The computing device of any one of claims 1 to 5 , wherein said program code, when executed by said processor, further causes said processor to verify an accuracy of said real-world three-dimensional magnetic field model of said magnetic field.

7 . The computing device of claim 6 , wherein said verifying an accuracy of said real-world three-dimensional magnetic field model of said magnetic field comprises:

receiving at least one additional magnetic field measurement entry comprising an amplitude value of said magnetic field and a corresponding positional coordinate;

estimating at least one additional error of amplitude between said default amplitude values of said real-world three-dimensional magnetic field model and at least one corresponding additional real-world amplitude value, wherein said at least one corresponding additional real-world amplitude value is determined from at least one additional magnetic field measurement entry including a corresponding positional coordinate; and

determining if said at least one additional error satisfies a verification threshold value to verify said accuracy of said real-world three-dimensional magnetic field model of said magnetic field.

8 . The computing device of any one of claims 1 to 7 , wherein said program code, when executed by said processor, further causes said processor to refine said real-world three-dimensional magnetic field model of said magnetic field.

9 . The computing device of claim 6 or 7 , wherein said program code, when executed by said processor, further causes said processor to refine said real-world three-dimensional magnetic field model of said magnetic field when said real-world three-dimensional magnetic field model of said magnetic field does not satisfy said verification of said accuracy of said real-world three-dimensional magnetic field model of said magnetic field.

10 . The computing device of claim 8 or 9 , wherein said refining of said real-world three-dimensional magnetic field model of said magnetic field comprises:

receiving said at least one additional magnetic field measurement entry comprising said amplitude value of said magnetic field and said corresponding positional coordinate;

estimating said at least one additional error of amplitude between said amplitude values of said real-world three-dimensional magnetic field model and said at least one corresponding real-world amplitude value of said at least one additional magnetic field measurement entry; and

adjusting said amplitude values of said real-world three-dimensional magnetic field model based on said at least one estimated additional error resulting in a refined real-world three-dimensional magnetic field model.

11 . The computing device of claim 9 , wherein said verifying is repeated after each of said refining to verify an accuracy of said resulting refined real-world three-dimensional magnetic field model and wherein said refining of said real-world three-dimensional magnetic field model of said magnetic field is repeated until said refined real-world three-dimensional magnetic field model satisfies said verification threshold.

12 . The computing device of any one of claims 1 to 11 , wherein said data is acquired with:

a magnetic field measuring device able to measure an amplitude of a magnetic field; and

a tracking device for identifying a location of said magnetic field measuring device;

wherein said magnetic field measuring device is used for determining said amplitude value of said magnetic field, and wherein said tracking device is used to measure said location of said magnetic field measuring device to determine said corresponding positional coordinates.

13 . The computing device of claim 12 , wherein said magnetic field measuring device further measures said value of orientation of said magnetic field.

14 . The computing device of claim 12 or 13 , wherein said magnetic field measuring device is a gaussmeter.

15 . The computing device of any one of claims 12 to 14 , wherein said magnetic field measuring device is coupled to at least one location marker that is trackable by said tracking device and wherein said tracking device determines a location of said at least one location marker to determine said location of said magnetic field measuring device.

16 . The computing device of claim 15 , wherein said at least one location marker is mounted on a frame coupled to said magnetic field measuring device, wherein said at least one location marker is positioned and said frame is shaped so as to reduce uncertainties of said location.

17 . The computing device of any one of claims 12 to 16 , wherein said magnetic field measuring device is coupled to said medical device for said measuring said amplitude value of said magnetic field.

18 . The computing device of claim 17 , wherein said a magnetic field measuring device is coupled to said medical device by way of a position stage, wherein said position stage is used to change said location of said magnetic field measuring device relative to said magnetic field of said magnetic field source of said medical device.

19 . The computing device of claim 17 or 18 , wherein said magnetic field measuring device is coupled to a patient table of said medical device and wherein said table is moved to change said location of said magnetic field measuring device relative to said magnetic field of said magnetic field source of said medical device.

20 . The computing device of any one of claims 12 to 19 , wherein said location of said magnetic field measuring device is comprised within a working region of said medical device.

21 . The computing device of any one of claims 1 to 20 , wherein said input interface is connectable to another computing device or another memory storing said data and providing said data to said processor,

22 . The computing device of any one of claims 15 to 21 , wherein said at least one location marker is a reflective marker, and wherein said tracking device is a stereo camera tracking said location of one or more of said at least one location marker to determine said location of said magnetic field measuring device.

23 . The computing device of any one of claims 15 to 22 , wherein said at least one location marker comprises at least three location markers, wherein said corresponding positional coordinates are determined by triangulation using said locations of said at least three location markers determined by said tracking device.

24 . The computing device of any one of claims 1 to 23 , wherein said magnetic field source is a first magnetic field source, wherein said representation of said magnetic field of said magnetic field source of said medical device is used with a representation of a magnetic field of at least one other magnetic field source of said medical device to generate a computer model of a combined magnetic field comprising said magnetic field of said first magnetic field source and of at least said magnetic field of said at least one other magnetic field source.

25 . The computing device of claim 24 , wherein each of said first magnetic field source and said at least one other magnetic field source comprises at least one electromagnet.

26 . The computing device of claim 25 , wherein said magnetic-field-based medical device comprises three pairs of magnetic field sources comprising said first magnetic field source and wherein said at least one other magnetic field source comprises five magnetic field sources.

27 . The computing device of claim 26 , wherein said three pairs of magnetic field sources is orthogonal with respect to each of said other two pairs of said three pairs.

28 . The computing device of any one of claims 1 to 27 , wherein said medical device is a system for steering self-propelled magnetotactic entities in a subject.

29 . A method of representing a magnetic field of a magnetic source of a medical device with a computer model of said magnetic field, comprising:

acquiring, for a plurality of locations, an amplitude value of said magnetic field and corresponding positional coordinates of each of said locations;

acquiring a theoretical three-dimensional model of said magnetic field;

estimating errors of amplitude between said default values of said theoretical three-dimensional model and said corresponding amplitude values of said plurality of magnetic field measurement entries based on said positional coordinates of said plurality of magnetic field measurement entries; and

adjusting default values of said theoretical three-dimensional model based on said estimated errors, resulting in a real-world three-dimensional magnetic field model of said magnetic field of said magnetic source of said medical device from said theoretical three-dimensional model with adjusted amplitude values.

30 . The method of claim 29 , further comprising:

providing said medical device; and

generating a magnetic field with a magnetic field source of said medical device; and

wherein said acquiring said amplitude value of said magnetic field and said corresponding positional coordinates comprises:

providing a magnetic field measuring device able to measure an amplitude of said magnetic field;

providing a tracking device able to determine a location of said magnetic field measuring device;

measuring, for each of said plurality of locations, said amplitude value of said magnetic field using said magnetic field measuring device; and

acquiring, for each of said plurality of locations, said corresponding positional coordinates of each of said measured amplitude values by determining, using said tracking device, a location of said magnetic field measuring device when completing each of said measuring of said amplitude values.

31 . The method of claim 29 or 30 , further comprising at least one of:

verifying an accuracy of said real-world three-dimensional magnetic field model of said magnetic field; and

refining said real-world three-dimensional magnetic field model of said magnetic field.

32 . The method of claim 31 , wherein said refining is performed if said real-world three-dimensional magnetic field model does not satisfy said verifying said accuracy.

33 . The method of claim 31 or 32 , wherein said verifying comprises:

receiving at least one additional amplitude value of said magnetic field for at least one additional location and additional corresponding positional coordinates;

for each of said at least one additional amplitude value, estimating an additional error of amplitude between said at least one additional amplitude value and an amplitude of said real-world three-dimensional magnetic field model based on positional coordinates of said real-world three-dimensional magnetic field model; and

determining if each of said estimated additional error of amplitude satisfies a verification threshold value to verify an accuracy of said real-world three-dimensional magnetic field model.

34 . The method of claim 31 or claim 32 , wherein said refining comprises:

providing at least one additional amplitude value of said magnetic field for at least one additional location and additional corresponding positional coordinates;

for each on said at least one additional amplitude value, estimating an additional error of amplitude between said at least one additional amplitude value and an amplitude of said real-world three-dimensional magnetic field model based on positional coordinates of said real-world three-dimensional magnetic field model; and

adjusting said amplitude of said real-world three-dimensional magnetic field model based on said estimated additional error of amplitude.

35 . The method of claim 34 , wherein said refining is repeated, with at least one further additional amplitude value of said magnetic field for at least one further additional location and further additional corresponding positional coordinates, until said real-world three-dimensional magnetic field model satisfies said verifying said accuracy.

36 . The method of any one of claims 29 to 35 , further comprising generating a complete three-dimensional magnetic field model of a complete magnetic field of said medical device generated by a plurality of said magnetic field sources by combining said real-world three-dimensional magnetic field model of each of said plurality of said magnetic field sources.

37 . The method of any one of claims 29 to 36 , further comprising sending said control parameters to controllers of said medical device, each controlling one magnetic field source of said plurality of magnetic field sources.

38 . A medical system comprising magnetic field sources of which said magnetic field of each of said magnetic field sources has been defined by performing said method as defined in any one of claims 29 to 37 .