Apparatus for and method of performing stereotaxic surgery

That which is claimed is:

1. A method for carrying out radiosurgery by selectively irradiating a target region within a living organism, comprising:

preparing a 3-dimensional mapping of at least a portion of the living organism, the mapping covering a mapping region which includes and is larger than the target region;

storing the mapping as reference data in digital form;

positioning the organism with the mapping region within the target region of a radio-surgical beaming apparatus which, when activated, emits a collimated radiosurgical beam via a path through a mass of healthy tissue of a strength sufficient to cause the target region to become necrotic;

passing first and second diagnostic beams, which are separate and distinct from the radiosurgical beam, through the mapping region substantially simultaneously, the first and second diagnostic beams being at a known non-zero angle relative to one another, to produce respective first and second images of respective first and second projections within the mapping region;

producing first and second digital electronic images representative of the first and second images;

digitally comparing the first and second electronic images with the reference data in digital form to provide position data representative of relative spatial locations of the collimated beam and of the target region, said first and second images being compared with said reference data sufficiently close in time after said images are produced by said first and second diagnostic beams such that said position data substantially represents real time spatial locations of the collimated beam and the target region relative to one another;

in response to said real time spatial locations of said collimated beam and target region, adjusting the relative positions of the beaming apparatus and the living organism in such a manner that the collimated beam is focused onto the target region;

activating the beaming apparatus and thereafter maintaining it in its activated state for the time necessary to provide a desired amount of irradiation;

as radiosurgery is carried out, periodically repeating the comparing step at small time intervals using newly produced first and second images such that any movement of the target region relative to the focus of the collimated beam is detected in substantially real time; and

repeating the adjusting step, as needed, to maintain the focus of the collimated beam on the target region.

2. A method as set forth in claim 1, wherein the repeating of the adjusting is carried out automatically in response to the position data obtained in the comparing step.

3. A method as set forth in claim 2, wherein the collimated surgical beam is an x-ray beam.

4. A method as set forth in claim 3, wherein the diagnostic beams are x-ray beams.

5. A method as set forth in claim 4, wherein the 3-dimensional mapping is prepared from a CAT scan procedure and is stored in digital form.

6. A method as set forth in claim 5, wherein the adjusting of the relative positions of the beaming apparatus and the living organism comprises moving the beaming apparatus while the living organism remains substantially stationary.

7. A method as set forth in claim 6, further including providing a selected total dose of irradiation by:

dividing the total dose into fractional doses;

utilizing the method of claim 6 to provide each fractional dose; and

supplying the fractional doses during time periods spaced apart in time from one another.

8. A method as set forth in claim 6, wherein the organism is part of a living body and wherein the target region is at a location in the body where sufficient bone structure is not present to mount an external reference frame.

9. A method as set forth in claim 6, further including, at some time prior to the mapping step:

implanting one or more fiducials in the mapping region.

10. A method as set forth in claim 1, wherein the collimated surgical beam is an x-ray beam.

11. A method as set forth in claim 10, wherein the diagnostic beams are x-ray beams.

12. A method as set forth in claim 11, wherein the 3-dimensional mapping is prepared from a CAT scan procedure and is stored in digital form.

13. A method as set forth in claim 12, wherein the adjusting of the relative positions of the beaming apparatus and the living organism comprises moving the beaming apparatus while the living organism remains substantially stationary.

14. A method as set forth in claim 13, further including providing a selected total dose of irradiation by:

dividing the total dose into fractional doses;

utilizing the method of claim 13 to provide each fractional dose; and

supplying the fractional doses during time periods spaced apart in time from one another.

15. A method as set forth in claim 13, wherein the organism is part of a living body and wherein the target region is at a location in the body where sufficient bone structure is not present to mount an external reference frame.

16. A method as set forth in claim 13, further including, at some time prior to the mapping step:

implanting one or more fiducials in the mapping region.

17. A method as set forth in claim 11, wherein the adjusting of the relative positions of the beaming apparatus and the living organism comprises moving the beaming apparatus while the living organism remains substantially stationary.

18. A method as set forth in claim 17, further including providing a selected total dose of irradiation by:

dividing the total dose into fractional doses;

utilizing the method of claim 17 to provide each fractional dose; and

supplying the fractional doses during time periods spaced apart in time from one another.

19. A method as set forth in claim 17, wherein the organism is part of a living body and wherein the target region is at a location in the body where sufficient bone structure is not present to mount an external reference frame.

20. A method as set forth in claim 17, further including, at some time prior to the mapping step:

implanting one or more fiducials in the mapping region.

21. A method as set forth in claim 1, wherein the diagnostic beams are x-ray beams.

22. A method as set forth in claim 21, wherein the 3-dimensional mapping is prepared from a CAT scan procedure and is stored in digital form.

23. A method as set forth in claim 22, wherein the adjusting of the relative positions of the beaming apparatus and the living organism comprises moving the beaming apparatus while the living organism remains substantially stationary.

24. A method as set forth in claim 1, wherein the adjusting of the relative positions of the beaming apparatus and the living organism comprises moving the beaming apparatus while the living organism remains substantially stationary.

25. A method as set forth in claim 1, further including providing a selected total dose of irradiation by:

dividing the total dose into fractional doses;

utilizing the method of claim 1 to provide each fractional dose; and

supplying the fractional doses during time periods spaced apart in time from one another.

26. A method as set forth in claim 1, wherein the organism is part of a living body and wherein the target region is at a location in the body where sufficient bone structure is not present to mount an external reference frame.

27. A method as set forth in claim 26, further including, at some time prior to the mapping step:

implanting one or more fiducials in the mapping region.

28. A method as set forth in claim 1, further including, at some time prior to the mapping step:

implanting one or more fiducials in the mapping region.

29. A method as set forth in claim 1, further including:

Repositioning the beaming apparatus such that, when activated, it emits the collimated beam such that the mapping region is within the target region and such that the collimated beam is directed via a different path through a different mass of healthy tissue to thereby minimize necrosis of healthy tissue; and

activating the beaming apparatus.

30. A method as set forth in claim 29, wherein the repositioning is within a plane and extends over an angle greater than 180.degree..

31. A method as set forth in claim 29, wherein the repositioning is over 3-dimensions.

32. A method as set forth in claim 1, further including:

periodically or continuously repositioning the beaming apparatus that emits the collimated beam in such a manner that the mapping region is within the target region and the collimated beam is periodically or continuously directed via different paths through different masses of healthy tissue to thereby minimize necrosis of healthy tissue.

33. A method as set forth in claim 32, wherein the repositioning is within a plane and extends over an angle greater than 180.degree..

34. A method according claim 1 wherein said radiosurgery is carried out on a human head without the use of a frame or any other external radiosurgery beam positioning reference.

35. A method according to claim 1 wherein said radiosurgical beaming apparatus includes a beam aiming member and wherein said apparatus is operated in a way which causes the aiming member to move continuously along a path transverse to the radiosurgical beam during radiosurgery.

36. A method according to claim 35 wherein said aiming member includes a gantry.

37. A method according to claim 35 wherein said aiming member includes a robotic arm.

38. An apparatus for carrying out radiosurgery by selectively irradiating a target region of living tissue within a living organism, comprising:

a digital data storage memory having stored therein a 3-dimensional mapping of at least a portion of the living organism, the mapping covering a mapping region which includes and is larger than the target region;

a beaming apparatus which, when activated, is adapted to emit a collimated radio surgical beam of a strength sufficient to cause the target region to become necrotic;

means for selectively activating the beaming apparatus;

means for passing first and second diagnostic beams, which are separate and distinct from said radiosurgical beam, through the mapping region substantially simultaneously, the first and second diagnostic beams being at a known non-zero angle relative to one another, to produce respective first and second images of respective first and second projections within the mapping region;

means for producing first and second digital electronic images representative of the first and second images;

means for digitally comparing the 3-dimensional mapping in digital form with the electronic images representative of the first and second images sufficiently close in time after said images are produced to derive therefrom data representative of a real time location of the target region; and

means for adjusting the relative positions of the beaming apparatus and the living organism as needed due to any movement of the target region relative to the collimated beam in response to the data representative of the real time location of the target region in such a manner that the collimated beam, when activated, is continuously focused onto the target region.

39. An apparatus as set forth in claim 38, wherein the collimated surgical beam produced by the beaming apparatus is an x-ray beam.

40. An apparatus as set forth in claim 39, wherein the means for passing diagnostic beams through the mapping region passes x-ray beams through the mapping region.

41. An apparatus as set forth in claim 40, wherein the 3-dimensional mapping is prepared from a CAT scan procedure and is stored in digital form in the data storage memory.

42. An apparatus as set forth in claim 41, wherein the means for adjusting the relative positions of the beaming apparatus and the living organism moves the beaming apparatus while the living organism remains substantially stationary.

43. An apparatus as set forth in claim 38, wherein the 3-dimensional mapping is prepared from a CAT scan procedure and is stored in digital form in the data storage memory.

44. An apparatus as set forth in claim 43, wherein the means for producing electronic signals representative of the diagnostic beams produces such signals in digital form.

45. An apparatus as set forth in claim 44, wherein the means for adjusting the relative positions of the beaming apparatus and the living organism moves the beaming apparatus while the living organism remains substantially stationary.

46. A method for selectively aligning a target region within a living organism with a linearly extendable surgical instrumentality, comprising:

preparing a 3-dimensional mapping of at least a portion of the living organism, the mapping covering a mapping region which includes and is larger than the target region;

storing the mapping as reference data in digital form;

positioning the organism with the mapping region within the target region of a surgical apparatus which, when activated, causes the linearly extendable surgical instrumentality to extend to the target region;

substantially simultaneously passing first and second diagnostic beams, which are separate and distinct from said instrumentality, through the mapping region, the first and second diagnostic beams being at a known non-zero angle relative to one another, to produce respective first and second images of respective first and second projections within the mapping region;

producing first and second electronic images representative of the first and second images;

comparing the first and second electronic images with the reference data to provide 3-dimensional position data representative of the relative spatial locations of the linearly extending surgical instrumentality and of the target region, said first and second images being compared with said reference data sufficiently close in time after said images are produced by said first and second diagnostic beams such that said data represents substantially the real time locations of said instrumentality and the target region relative to one another; and

adjusting the relative positions of the surgical apparatus and the living organism in such a manner that the linearly extending surgical instrumentality is aimed at the target region.

47. A method according to claim 46 wherein said instrumentality is a solid instrument such as a biopsy probe.

48. A method according to claim 46 wherein said instrumentality is a radiosurgical beam.

49. An apparatus for selectively aligning a target region of living tissue within a living organism with a linearly extendable surgical instrumentality, comprising:

a data storage memory having stored therein a 3-dimensional mapping of at least a portion of the living organism, the mapping covering a mapping region which includes and is larger than the target region;

a surgical apparatus which, when activated, is adapted to extend a linearly extendable surgical instrumentality to the target region;

means for selectively activating the surgical apparatus;

means for substantially simultaneously passing first and second diagnostic beams, which are separate and distinct from said instrumentality, through the mapping region periodically, the first and second diagnostic beams being at a known non-zero angle relative to one another, to produce periodically pairs of respective first and second images of respective pairs of first and second projections within the mapping region;

means for producing first and second digital electronic images representative of the first and second images;

means for comparing the 3-dimensional mapping in digital form with the first and second digital electronic images representative of the first and second images sufficiently close in time after said images are produced to derive therefrom data representative of a 3-dimensional real time location of the target region; and

means for adjusting relative positions of the surgical apparatus and the living organism in response to the data representative of the 3-dimensional real time location of the target region in such a manner that the linearly extending surgical instrumentality, when activated, is aimed at the target region.

50. A method for carrying out radiosurgery by selectively irradiating a target region within a living organism, comprising:

preparing a 3-dimensional mapping of at least a portion of the living organism, the mapping covering a mapping region which includes and is larger than the target region;

storing the mapping as reference data;

positioning the organism with the mapping region within the target region of a radiosurgical beaming apparatus which, when activated, emits a collimated radiosurgical beam from a beam aiming member forming part of the apparatus via a path through a mass of healthy tissue of a strength sufficient to cause the target region to become necrotic, said apparatus being operated in a way which causes said aiming member to move continuously along a path transverse to the beam during radiosurgery;

during movement of said aiming member, passing first and second diagnostic beams, which are separate and distinct from the radiosurgical beam, through the mapping region substantially simultaneously, the first and second diagnostic beams being at a known non-zero angle relative to one another, to produce respective first and second images of respective first and second projections within the mapping region;

producing first and second digital electronic images representative of the first and second images;

digitally comparing the first and second electronic images with the reference data in digital form to provide position data representative of relative spatial locations of the collimated beam and of the target region, said first and second images being compared with said reference data sufficiently close in time after said images are produced by said first and second diagnostic beams such that said position data substantially represents real time spatial locations of the collimated beam and the target region relative to one another;

in response to said real time spatial locations of said collimated beam and target region, adjusting the relative positions of the beaming apparatus and the living organism in such a manner that the collimated beam is focused onto the target region;

activating the beaming apparatus and thereafter maintaining it in its activated state for the time necessary to provide a desired amount of irradiation;

as radiosurgery is carried out, periodically repeating the comparing step at small time intervals during movement of said aiming member using newly produced first and second images such that any movement of the target region relative to the focus of the collimated beam is detected in substantially real time; and

repeating the adjusting step, as needed, to maintain the focus of the collimated beam on the target region.

51. A method according to claim 50 wherein said radiosurgery is carried out on a human head without the use of a frame or any other external radiosurgery beam positioning reference.

Description Submit all comments and votes

TECHNICAL FIELD

The present invention relates to an apparatus and method for extending a surgical instrumentality to a target region in a patient, for example, for performing stereotaxic surgery, suitably using an x-ray linear accelerator. A collimated beam from the accelerator is used to cause tissue, for example tumorous tissue, to become necrotic. In another embodiment a biopsy probe can be extended to the target area. The invention is primarily concerned with assuring that the collimated beam, biopsy probe or other surgical instrumentality is properly aligned to extend to the tissue which is to be rendered necrotic, from which a sample is to be removed, or the like.

BACKGROUND OF THE INVENTION

The use of stereotaxic radiosurgery to render tissue, particularly tumorous tissue, necrotic is well known. In general, this technique has been utilized for brain surgery but has not been used for surgery elsewhere in a patient's body. The reason for the limitation to brain surgery is that if the beam is to be properly aimed or focused onto a target region which is to be rendered necrotic, it is necessary to provide an external radio-opaque frame which is in a fixed position relative to the targeted region. The frame is precisely positionable in space and provides a reticle which can be observed by passing diagnostic x-ray beams through the frame and through a region of the body which includes the target region to be irradiated thereby allowing the position of the patient or of the beaming apparatus to be adjusted so that it is properly focused upon that region. Most portions of the body do not have available bone structure to which such a frame can be readily attached.

Stereotaxis is a branch of neurosurgery that utilizes spatial information provided by neuroradiologic studies to treat certain disorders of the central nervous system with great accuracy. Conventional stereotaxis, as mentioned above, uses an external frame anchored with screws to the patient's skull as a frame of reference for both localizing (by radiologic studies) and treating intracranial tumors and malformations. Stereotaxic radiosurgery builds on this concept by combining the precise localizing capabilities of stereotaxis with a high-energy radiation source. Over the past twenty years several independent groups have utilized radiosurgical techniques to treat a variety of brain disorders with single large fractions of radiation. In contrast to conventional radiation therapy (where the target tissue and the surrounding healthy tissue are substantially equally exposed to radiation and the healthy tissue is expected to have a higher resistance to radiation damage), the rationale behind such a procedure is that eventually radionecrosis will be produced at the targeted site. Because the outcome of this procedure is theoretically the same as standard resective surgery, the term radiosurgery was coined. The constantly growing list of indications for radiosurgical treatment includes arteriovenous malformations, acoustic neurinomas, metastatic lesions, unresectable skull base meningiomas, and several types of tumors involving the brain stem, pituitary and pineal region. Even Parkinson's disease and obsessive-compulsive disorders have been treated at the Karolinska Institute in Stockholm by creating well-circumscribed necrotic lesions in discrete brain locations. In many clinical situations stereotaxic radiosurgery is widely acknowledged as the treatment of choice.

The radiosurgical principle of confining radiation as much as possible only to the volume of a brain tumor is both a significant and timely concept. Meanwhile, the development of new technologies and the favorable clinical results that have been observed has lead to dramatic increases in the numbers of patients currently being treated with stereotaxic radiosurgery. Although exact figures are impossible to find at this point, reports in the literature and discussions with experts in the field of radiosurgery suggest that already several thousand patients per year, worldwide, are being treated with this technique. Despite such growing enthusiasm for stereotaxic radiosurgery, numerous theoretically attractive uses of such therapy remain impractical because of limitations in current instrumentation.

Although conventional stereotaxic radiosurgery combines a necrosing dose of energy largely to the lesion in question, there are limits to this capacity (regardless of radiation source) and inevitably normal brain is in some measure also irradiated. Overall, the smaller the volume of brain that is irradiated, the less the risk of healthy tissue radionecrosis. In the ideal situation, i.e., the treatment of very small volume lesions, normal tissue tolerance is not an issue for radiosurgeons. However, for both radiophysical and radiobiological reasons, radiosurgical treatment of the more frequently encountered larger lesions is problematic. With a risk that is proportional to both dose and the volume irradiated, radiation neorosis of the brain adjacent the treated lesion remains the major complication of stereotaxic radiosurgery. Consequently, despite the precision of stereotaxic radiosurgery, the normal tolerance to a large single dose of radiation is often a concern and strict attention must be paid to dose and volume parameters. This holds true for every radiosurgical technique regardless of radiation source.

The apparatus and method of the present invention have several advantages over other currently available radiosurgical systems. In particular, when operating in accordance with the present invention it is possible to perform multiple fraction radiosurgical treatment (separating the overall dose into a plurality of fractional doses and delivering the fractional doses hours or even days or weeks apart) utilizing the apparatus and method of the present invention. Consequently, a new type of ionizing radiation therapy is provided for brain tumors, one that blends conventional radiation therapy techniques with surgical principles of accurate anatomic localization. Presently there is no practical method for delivering multiple fraction precision radiation treatment to brain tumors because a frame must be left attached to the patient's skull with screws for the entire time of treatment which may desirably be weeks if one is attempting to minimize healthy tissue radioneorosis. In making precise multiple fraction therapy feasible, widespread application of the technique is possible in the treatment of the many tumors that are currently poorly treated with either surgery or radiation therapy.

The problems encountered in the radiosurgical treatment of the more frequently encountered larger lesions have provided much of the impetus for development of the present invention. Although the intent of the conventional stereotaxic radiosurgical treatment is to induce radionecrosis throughout the entire volume of a targeted tumor or malformation, one is limited by the above-described radiophysical and biological problems. Fractionated radiosurgery, which can be carried out using the apparatus and method of the present invention, is intended to accomplish the same objective, yet normal brain immediately adjacent to the tumor inherently receives a more tolerable dose and fraction. The total dose of radiation to the tumor can be pushed high enough to induce necrosis, yet still provide normal tissues, which received much less radiation, enough time for cell repair. Comparison between the cell kinetics of normal brain and the lesion being treated are only relevant as they pertain to this issue. It is critical to keep in mind that normal brain is relatively tolerant of even very high radiation doses delivered to small volumes. Furthermore, since in one reported instance a patient died from acute uncontrollable tumor and brain edema immediately following stereotaxic irradiation of a large tumor, there should be a benefit to inducing gradual neorosis in large tumors with fractionated therapy.

Despite the theoretical benefits of fractionated radiosurgical treatment, current techniques of stereotaxic localization precludes such an approach. Specifically, the major obstacle is a need for an external frame, attached to the patient's head with screws, which is impractical, if not impossible, to keep in place over the several days to few weeks needed to carry out such a therapy. Since the present invention does not rely on rigidly connected frames, it readily circumvents this problem. In addition, the computer mediated stereotaxic radiosurgery of the invention, with minor modifications, opens up the possibility of using radiosurgery outside the cranium, a thoroughly unexplored concept. Given the phenomenal development of new imaging techniques over the past fifteen years, there is now the means to visualize accurately nearly all body structures, and as a consequence, it seems reasonable that stereotaxic radiosurgical principles shall be of benefit in the treatment of non-brain neoplasms as well. Furthermore, since stereotaxic radiosurgery often provides a substitute for resective surgery, its utilization will lead to major savings for society.

As is apparent from the above discussion, it would be desirable to have a stereotaxic radiosurgical instrument which would be capable of use elsewhere than for brain surgery, which indeed could be used to excise non-tumorous tissue such as glands, if desired, which would operate with substantially no patient discomfort and which would make possible the convenient and safe use of doses of radiation accurately delivered in separate fractions, if need be, over a total elapsed time period of several day or weeks.

It is also desirable to be able to properly and accurately align other surgical instrumentation, e.g., a biopsy probe which can then be extended linearly into a patient up to a tumor or the like where sampling can be performed.

DISCLOSURE OF INVENTION

The present invention is directed to overcoming one or more of the problems as set forth above.

In accordance with an embodiment of the invention a method is set forth for selectively irradiating a target region within a living organism. The method comprises preparing a 3-dimensional mapping of at least a portion of the living organism, the mapping covering a mapping region which includes and is larger than the target region. The mapping is stored as reference data. The organism is positioned with the mapping region within the target area of a beaming apparatus which, when activated, emits a collimated surgical beam of a strength sufficient to cause the target region to become necrotic. First and second diagnostic beams are passed through the mapping region with the beams being at a known non-zero angle relative to one another. The beams are used to produce respective first and second images of respective first and second projections within the mapping region. Electronic images are produced which are representative of the first and second images. The electronic images are compared with the reference data to provide position data representative of the relative spatial locations of the collimated beam and of the target region. The relative positions of the beaming apparatus and the living organism are adjusted in such a manner that the collimated beam is focused on the target region. The comparison is repeated at small time intervals and, when the comparison so indicates, the adjusting step is repeated, as needed, and in such a manner that the collimated beam remains focused on to the target region.

In accordance with another embodiment of the present invention an apparatus is set forth for selectively irradiating a target region of living tissue within a living organism. The apparatus includes a data storage memory having stored therein a 3-dimensional mapping of at least a portion of a living organism, the mapping covering a mapping region which includes and is larger than the target region. A beaming apparatus is present which, when activated, is adapted to emit a collimated surgical beam of a strength sufficient to cause the target region to become necrotic. Means are provided for selectively activating the beaming apparatus. Means are provided for passing first and second diagnostic beams through the mapping region, the first and second diagnostic beams being at a known non-zero angle relative to one another, to produce respective first and second images of respective first and second projections within the mapping region. Means are provided for producing electronic images from and representative of the first and second images. Means are provided for comparing the 3-dimensional mapping stored in the data storage memory with the electronic images representative of the first and second images to derive therefrom data representative of the real time location of the target region. Means are provided for adjusting the relative positions of the beaming apparatus and the living organism as needed in response to the data representative of the real time location of the target region in such a manner that the collimated beam, when activated, is continuously focused on to the target region.

In accordance with yet another embodiment of the invention a method is set forth for selectively aligning a target region within a living organism with a linearly extendable surgical instrumentality. The method comprises preparing a 3-dimensional mapping of at least a portion of the living organism, the mapping covering a mapping region which includes and is larger than the target region. The mapping is stored as reference data. The organism is positioned with the mapping region within the target area of a surgical apparatus which, when activated, causes the linearly extendable surgical instrumentality to extend to the target region. First and second diagnostic beams are passed through the mapping region, the first and second diagnostic beams being at a known non-zero angle relative to one another, to produce respective first and second images of respective first and second projections within the mapping region. Electronic images are produced representative of the first and second images. The electronic images are compared with the reference data to provide position data representative of the relative spatial locations of the linearly extending surgical instrumentality and of the target region. The relative positions of the surgical apparatus and the living organism are adjusted in such a manner that the linearly extending surgical instrumentality is aimed at the target region.

In accordance with another embodiment still of the invention an apparatus is disclosed for selectively aligning a target region of living tissue within a living organism. The apparatus comprises a data storage memory having stored therein a 3-dimensional mapping of at least a portion of the living organism, the mapping covering a mapping region which includes and is larger than the target region. a surgical apparatus is provided which, when activated, is adapted to extend a linearly extendable surgical instrumentality to the target region. Means are provided for selectively activating the surgical apparatus. Means are provided for passing first and second diagnostic beams through the mapping region, the first and second diagnostic beams being at a known non-zero angle relative to one another, to produce respective first and second images of respective first and second projections within the mapping region. Means are provided for producing electronic images representative of the first and second images. Means are present for comparing the 3-dimensional mapping with the electronic images representative of the first and second images to derive therefrom data representative of the real time location of the target region. Means are provided for adjusting the relative positions of the surgical apparatus and the living organism in response to the data representative of the real time location of the target region in such a manner that the linearly extending surgical instrumentality, when activated, is aimed at the target region.

The apparatus and method set forth above have a number of advantages over prior art stereotaxic radiosurgical methods and apparatus. First of all, the need for an external frame is completely eliminated with the frame being replaced by the 3-dimensional mapping. Second, since it is not necessary to mount a frame to the patient's body, pain from such a frame is eliminated as is the possibility of infection. Third, stereotaxic radiosurgery can be utilized virtually anywhere in the patient's body. Fourth, stereotaxic radiosurgical procedures can be conveniently and accurately carried out in a fractionated manner over as long a period of time as desired, for example, over several days or weeks, if necessary or desirable.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood by reference to the figures of the drawings wherein like numbers denote like parts throughout and wherein:

FIG. 1 illustrates, in isometric view, one embodiment of an apparatus in accordance with the present invention;

FIG. 2 illustrates, schematically, diagnostic x-ray imaging and accelerator focusing aspects of the present invention;

FIG. 3 illustrates, in a view similar to FIG. 1, an alternative embodiment of an apparatus in accordance with the present invention; and

FIG. 4 illustrates, schematically, a system block diagram in accordance with an embodiment of the present invention.

BEST MODE FOR CARRYING OUT INVENTION

The present invention provides a stereotaxic radiosurgical apparatus 10, an embodiment of which is illustrated in FIG. 1.

In accordance with the invention a data storage memory is provided. The data storage memory can be in a data processor 12, for example, a microprocessor 12 or in an auxiliary device such as a disc or tape storage unit 13 (FIG. 4). The microprocessor 12 or the storage unit 13 has stored therein a 3-dimensional mapping of at least a portion of a living organism, i.e., of a patient 14. If the storage unit 13 is present the 3-dimensional mapping data, normally in digital form, will generally be loaded into the microprocessor 12 for comparison purposes. The mapping covers a mapping region 16 (see FIG. 2) which includes and is larger than a target region 18 within the patient which is being selectively irradiated. The mapping region 16 of FIG. 2 is essentially the portion of the cranium 15 of the patient 14 so that bone structure is present to serve as an alignment reference. If desired, three or more fiducials 19 can be implanted, in which instance including bone structure as an alignment reference is not necessary. This could be done for treatments of the brain but could be particularly desirable or necessary in less bony areas of the body.

The 3-dimensional mapping can be obtained by conventional techniques. For example a CAT scan (CT) can be utilized to obtain this image or magnetic resonance imaging (MR) can be used to obtain this mapping. As is well known CT or computerized tomography operates through measurement of the