Determination and application of location and angular orientation of a pill transmitter within a body

• US 7,616,982 B1
• Filed: 06/22/2006
• Issued: 11/10/2009
• Est. Priority Date: 06/22/2006
• Status: Expired due to Fees

• Current Assignee: USA As Represented By The Administrator Of The NASA
• Original Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Inventors: Schipper, John F.
• Primary Examiner(s): Le; Long V
• Assistant Examiner(s): Abraham; Salieu M
• Application Number:
  US11/473,499
• Time in Patent Office: 1,237 Days
• Field of Search: 600/109, 600/114, 600/160, 600/309, 600/407, 600/424, 600/476, 348/45, 348/76, 606/1, 606/2, 702 94- 95, 702150-154, 340/870.01, 340/901
• US Class Current: 600/424
• CPC Class Codes: A61B 1/04 combined with photographic or television appliances
• CPC Class Codes: A61B 1/041 Capsule endoscopes for imaging
• CPC Class Codes: A61B 5/06 Devices, other than using radiation, for detecting or locating foreign bodies for removing same A61B17/50 ; determining position of probes within or on the body of the patient

Abstract

A mobile pill transmitter system that moves through or adjacent to one or more organs in an animal'"'"'s body and that provides signals from which the pill'"'"'s present location and/or present angular orientation can be determined. The system also provides signals from which the present roll angle of the pill, about a selected axis, can be determined. When the location coordinates and the roll angle of the pill are within selected ranges, an aperture on the pill container releases a selected chemical into or onto the body. Optionally, the pill as it moves also provides a sequence of visually perceptible images; the times for image formation may correspond to times at which the pill transmitter system location or image satisfies one or at least four different criteria.

Claims

1. A method for determination of at least one location coordinate and at least one angular orientation coordinate of a mobile device that moves within or adjacent to at least one organ in a human or other animal body, the method comprising:

(1) providing first and second spaced apart signal transmitting antennas, having index values i=1 and i=2, respectively, on the device, spaced apart along a selected axis of the device, and transmitting a first sequence and a second sequence of distinguishable signals at the first and second transmitting antennas, respectively, where the first and second transmitting antennas have location coordinates (x0+Δ

x0,y0+Δ

y0,z0+Δ

z0) and (x0−

Δ

x0,y0−

Δ

y0,z0−

Δ

z0), respectively, a central location of the mobile device has location coordinates (x0,y0,z0), and the coordinate values x0, y0, z0, Δ

x0, Δ

y0, Δ

z0 are to be determined, and (x,y,z) are location coordinates in a selected Cartesian coordinate system;

(2) receiving the first and second sequences of transmitted signals at least first, second, third and fourth spaced apart, non-coplanar signal receiving antennas, having index values j=1, 2, 3, 4, respectively, having substantially fixed and known location coordinates (xj,yj,zj), and being located adjacent to the body;

(3) for each transmitted signal in each of the first and second sequences, providing an elapsed time of signal propagation Δ

t(i,j) between the first transmitting antenna (i=1) or second transmitting antenna (i=2) and the first, second, third or fourth signal receiving antenna (j=1, 2, 3, 4, respectively), where Δ

t(i,j) is expressed by a relation

c′

²Δ

t(i=1,j)²=(xj−

x0+Δ

x0)²+(yj−

y0+Δ

y0)²+(zj−

z0+Δ

z0)²,

c′

²Δ

t(i=2,j)²=(xj−

x0−

Δ

x0)²+(yj−

y0−

Δ

y0)²+(zj−

z0−

Δ

z0)²,

where c′

is a representative value of propagation of a transmitted electromagnetic signal within the body;

(4) estimating the values Δ

x0, Δ

y0, Δ

z0, x0, y0 and z0 by the relations

2. The method of claim 1, further comprising evaluating accuracy of said angular orientation components by comparing a sum of squares of said angular orientation components, 4{Δ

x0²+Δ

y0²+Δ

z0²}, with a square d² of a known distance between two selected locations on said mobile device.

3. The method of claim 1, further comprising estimating a roll angle θ

of said mobile device about a selected axis by a process comprising;

selecting a location on said mobile device corresponding to a roll angle value, θ

=θ

3, about a selected axis for said mobile device;

providing a third signal transmitting antenna, numbered i=3, on said mobile device at a location selected with reference to the roll angle value θ

=θ

3;

providing a square Δ

t(3,j)² of elapsed time of signal propagation between the third signal transmitting antenna and at least one of said signal receiving antenna, numbered j,

providing a first selected angle value ψ

=(θ

3−

π

)/2 and a second selected angle value ψ

;

providing a value Δ

z0 for said angular orientation component and values, xi−

x0, yi−

y0 and zi−

z0, relating said location coordinate (x0,y0,z0) to corresponding location coordinate (xi,yi,zi) (I=1 or

     2) of said signal receiving antenna; and

estimating a roll angle θ

of said mobile device at least one time from a relation

4. The method of claim 3, further comprising choosing said angle ψ

to be ψ

=tan<sup>−

1</sup> {(yi−

y0)/(xi−

x0)}.

5. The method of claim 3, further comprising:

providing said mobile device with a controllable aperture and with a source of a selected chemical associated with the aperture;

estimating a time when (1) said location coordinates (x0,y0,z0) for said mobile device lie in selected ranges (xr1≦

x0≦

xr2,yr1≦

y0≦

yr2,zr1≦

z0≦

zr2) and (2) said roll angle θ

lies within a selected range, θ

r1≦

θ

≦

r2; and

when the conditions (1) and (2) are satisfied, causing said mobile device to release the selected chemical through the aperture.

6. The method of claim 1, further comprising:

causing said mobile device to form and transmit signals representing visually perceptible images at a sequence of two or more image formation times, when a selected criterion is satisfied.

7. The method of claim 6, further comprising choosing said selected criterion to comprise:

each image formation time corresponds to a time, t=t_f, at which said location coordinates (X0(t_f),y0(t_f),z0(t_f)) lie within one or more selected ranges (xf1≦

x0≦

xf2,yf1≦

y0≦

≦

yf2,zf1≦

z0≦

zf2).

8. The method of claim 6, further comprising choosing said criterion to comprise:

two consecutive image formation times, t=t_f1 and t=t_f2, correspond to locations (x0(t_f),y0(t_f),z0(t_f)) of said mobile device that satisfy

{(x0(t_f2)−

x0(t_f1)²+(y0(t_f2)−

y0(t_f1)²+(z0(t_f2)−

z0(t_f2)²}^1/2≧

Δ

r(thr),

where Δ

r(thr) is a selected threshold distance.

9. The method of claim 6, further comprising choosing said criterion to comprise:

two consecutive image formation time, t=t_f1 and t=t_f2 satisfy

|t_f2−

t_f1|≧

Δ

t(thr),

where Δ

t(thr) is a selected threshold separation time.

10. The method of claim 6, further comprising choosing said criterion to comprise:

providing a numerical measure ID(t₁;

t₂) of differences in an image formed by said mobile device at times t=t₁ and t=t₂ (>

t₁); and

the measure ID at two consecutive image formation times, t=t_f1 and t=t_f2 satisfies

ID(t_f1;

t_f2)≧

ID(thr),

where Δ

ID(thr) is a selected image difference threshold value.

11. The method of claim 1, further comprising choosing at least one of said sets of coordinate values, (x1,y1,z1), (x2,y2,z2), (x3,y3,z3) and (x4,y4,z4), to produce a magnitude of an inverse of a determinant, 1/|det(M)|, of said matrix M having a small positive value.