Patent Number: 
Section: claims

1. A computerized system for determining location by tracking a source of ionizing radiation, the system comprising:at least one first radiation detector capable of receiving ionizing radiation from the radiation source and for producing first output signals;at least one second radiation detector capable of receiving ionizing radiation from the radiation source and producing second output signals; andat least one processor configured to receive and use said first and second output signals to determine a plane in which the source resides, wherein the at least one processor is further configured to determine the plane when the source has an activity in the range of about 0.01 mCi to about 0.5 mCi. 2. The system of claim 1, wherein the at least one first radiation detector and the at one least second radiation detector are oriented to enable detection of the source when the source is connected to a medical device. 3. The system of claim 1, wherein said radiation source employs an isotope with a half life in the range of 6 to 18 months. 4. The system of claim 1, additionally comprising said radiation source capable of providing said radiation. 5. A system according to claim 1, wherein the processor is configured to determine a plane with respect to a center of mass of the source. 6. A system according to claim 1, further comprising a displacement mechanism configured to cause motion of at least one of the plurality of detectors, and wherein the at least one processor is configured to send signals to the displacement mechanism in response to radiation received, to track the radiation source. 7. A system according to claim 6, wherein the displacement mechanism is configured to track the radiation source by changing locations of detection boundaries in order to maintain the source within the detection boundaries. 8. The system of claim 1, additionally comprising:an imaging module, said imaging module being configured to provide an image signal to said at least one processor wherein said at least one processor is configured to translate the image signal into an image of a portion of a body of a subject. 9. The system of claim 8, further comprising a display device configured to display the body portion image. 10. The system of claim 9, wherein the source of radiation is connected to a medical device, and wherein said display device is configured to display the image of said portion of the body with a determined position of the medical device superimposed on said image of said portion of the body. 11. The system of claim 1, further comprising at least one third radiation detector for producing third signals, and wherein the processor is configured to determine the at least one plane using the first signals, the second signals, and the third signals. 12. The system of claim 11, further comprising an at least one fourth radiation detector for producing fourth signals, and wherein the processor is further configured to determine the at least one plane using the first signals, the second signals, the third signals and the fourth signals. 13. The system of claim 12, wherein the at least one plane is three planes. 14. The system of claim 11, wherein the at least one plane is three planes. 15. The system of claim 1, wherein the source includes a piece of radioactive metal implanted in a body of a subject. 16. The system of claim 15, wherein the piece of radioactive metal is a wire. 17. The system of claim 1, wherein each of the at least one first detector and the at least one second detector are part of at least one sensor module. 18. The system of claim 17, wherein said at least one sensor module includes at least three sensor modules. 19. The system of claim 18, further comprising at least three locomotion devices each associated with one of the at least three sensor modules, said at least three locomotion devices configured to impart translational motion to an associated sensor module in response to instructions from the at least one processor. 20. A system according to claim 18, wherein said at least three sensor modules includes at least four sensor modules, and wherein the at least one processor is configured to receive at least four output signals each defining a plane in which said radiation source resides, and to solve a resulting overdetermined set of equations to find a likely position of said radiation source, taking into account an error defined by a Euclidean distance between each plane and the position. 21. The system of claim 17, further comprising at least one locomotion device configured to impart translational motion to said at least one sensor module in response to an instruction generated by the at least one processor. 22. The system of claim 17, wherein said at least one processor receives at least two output signals each defining a plane in which said radiation source resides, and computes a linear intersection of the two planes upon which said radiation source is located. 23. The system of claim 17, wherein said at least one sensor module includes three sensor modules, and wherein the at least one processor is configured to receive at least three output signals each defining a plane in which said radiation source resides, and to compute a position of said radiation source by determining an intersection of three planes. 24. The system of claim 23, wherein said at least one processor is configured to compute said position repeatedly at predetermined intervals so that a position of said radiation source as a function of time may be plotted. 25. A method of determining a location of a radiation source, the method comprising:providing an ionizing radiation source having activity in the range of about 0.01 mCi to about 0.5 mCi;detecting from the source radiation in said range;determining based on said detected radiation a first plane in which said radiation source resides;determining based on said detected radiation at least a second plane in which said radiation source resides;locating said radiation source by calculating an intersection of said first plane and said at least a second plane. 26. The method of claim 25, wherein determining at least a second plane in which said radiation source resides includes determining at least a third plane in which said radiation source resides and wherein the method further comprises:calculating a location of intersection of said first plane, said second plane and said at least a third plane. 27. A system for determining a location associated with a source of ionizing radiation, the system comprising:at least one radiation detector configured to receive ionizing radiation from the radiation source and to produce output signals; andat least one processor configured to receive and use said output signals to determine a plane in which the source resides, wherein the at least one processor is further configured to determine the plane when the source has an activity in the range of about 0.01 mCi to about 0.5 mCi. 28. The system of claim 27, wherein the at least one radiation detector includes at least three radiation detectors, each configured to generate output signals, and wherein the at least one processor is further configured to use the output signals to identify a location within a body associated with the source. 29. The system of claim 28, wherein the at least one processor is further configured to generate instructions for aiming a therapeutic beam at the location. 30. The system of claim 28, wherein the location is an area of tissue located proximate the source. 31. The system of claim 28, wherein the at least one processor is further configured to identify relative movement between the source and the at least one radiation detector and to adjust orientations of the at least one radiation detector in response to the identified relative movement. 32. The system of claim 31, wherein the at least one processor is configured to repeatedly re-aim the at least one radiation detector toward the source in response to repeated relative movement between the source and the at least one radiation detector. 33. The system of claim 27, wherein the at least one processor is configured to cooperate with the at least one radiation detector to identify a location associated with the source when the source is a radioactive piece of metal within a body of a subject. 34. The system of claim 27, wherein the at least one processor is configured to cooperate with the at least one radiation detector, to identify a location associated with the source when the source is a radioactive piece of metal associated with a movable medical device having a portion for use within a body of a subject. 35. The system of claim 27, wherein the at least one radiation detector includes a plurality of radiation detectors, and wherein the system further includes a plurality of locomotion devices configured to receive signals from the at least one processor for re-aiming the plurality of radiation detectors toward the source when relative movement occurs between the source and the plurality of radiation detectors. 36. The system of claim 27, wherein the at least one processor is configured to identify, within a body of a subject, a location associated with the source, and wherein the at least one processor is further configured to receive information for constructing an image of the location, wherein the at least one process is further configured to output signals for displaying a location indicator superimposed on the image. 37. The system of claim 27, wherein the at least one radiation detector includes a plurality of radiation detectors configured to generate a plurality of signals, and wherein the at least one processor is configured to use the plurality of signals to identify a three dimensional location associated with the sensor. 38. The system of claim 37, wherein the at least one processor identifies the three dimensional location by calculating an intersection of at least three planes. 39. The system of claim 37, wherein the at least one processor is configured to receive information indicative of relative movement between the source and the plurality of radiation detectors, and to generate instructions for adjusting positions of the plurality of radiation detectors in response to the relative movement. 40. A system for determining a location by tracking a source of ionizing radiation, the system comprising:at least one radiation detector being configured to receive ionizing radiation from a source having a half life of between 6 and 18 months and to produce output signals; andat least one processor configured to receive and use said output signals to determine a plane in which the source resides.