Apparatus for and method of carrying out stereotaxic radiosurgery and radiotherapy

• US 5,427,097 A
• Filed: 12/10/1992
• Issued: 06/27/1995
• Est. Priority Date: 12/10/1992
• Status: Expired due to Term

• Current Assignee: Accuray Incorporated
• Original Assignee: Accuray Incorporated
• Inventors: Depp, Joseph G.
• Primary Examiner(s): Cohen, Lee S.
• Assistant Examiner(s): GILBERT, SAMUEL G
• Application Number:
  US07/989,045
• Time in Patent Office: 929 Days
• Field of Search: 364/413.24, 364/413.25, 364/413.26, 378/195, 378/196, 378/197, 378/198, 378/205, 378/208, 378/65, 378/17, 128/653.1, 128/660.01, 128/660.08, 128/660.09, 128/660.1, 128/906, 606/130
• US Class Current: 600/427
• CPC Class Codes: A61B 2090/101 for stereotaxic radiosurgery
• CPC Class Codes: A61B 34/30 Surgical robots
• CPC Class Codes: A61N 2005/1061 using an x-ray imaging system having a separate imaging source
• CPC Class Codes: A61N 5/1049 for verifying the position of the patient with respect to the radiation beam

Abstract

There is disclosed herein a technique for carrying out stereotaxic radiosurgery or radiotherapy on a particular target region within a patient by a radiosurgical/radiotherapeutic beam of radiation which is at least intermittently directed along a beam path through the target region. One particular beam generating arrangement illustrated is carried by a robotic arm which is movable in at least three dimensions. In accordance with one embodiment disclosed herein, a method and apparatus are provided for moving the robotic arm and beam generating arrangement along a predetermined, non-circular and non-linear path transverse to the beam path while, at the same time, the beam path is directed into the target region. In this way, the radiosurgical/radiotherapeutic beam can be directed through the target region from particular treatment points along the transverse path so as to define a non-spherical target region. In accordance with a second embodiment, the apparatus disclosed herein includes an emergency stop arrangement separate from and independent of the controlling the robotic arm controller for automatically stopping all movement of the robotic arm and turning off the beam if the robotic arm deviates from its intended transverse path. In a third embodiment, the apparatus utilizes a plurality of target locating beams of radiation apart from but cooperating with the radiosurgical/radiotherapeutic beam to accurately and continuously locate the target region in substantially real time.

Claims

1. An apparatus for carrying out stereotaxic surgery on a particular target region including a target and indicating a position of the target region with respect to a surrounding area also containing certain nearby reference points each having a location, said apparatus comprising:

(a) a radiation beam generator including a delivery mechanism;

(b) means for generating target locating beams;

(c) first means for intermittently directing a radiosurgical beam of radiation along a beam path into the target region;

(d) second means for intermittently directing a plurality of target locating beams of radiation into and through the surrounding area containing the target region and reference points so that the target locating beams, after passing through the surrounding area, contain location data indicating the locations of the reference points within the surrounding area;

(e) third means responsive to said intermittently directed target locating beams (i) for obtaining the location data from said target locating beams, (ii) for intermittently comparing the location data so obtained with the previously obtained reference data, and (iii) for determining from each of the intermittent comparisons a position of the target region with respect to the locations of the reference points as a result of each such comparison;

(f) fourth means for operating said first, second and third mentioned means in cooperation with one another (i) such that said radiosurgical beam is directed into said target region only during intermittent treatment periods and alternatively therewith, said target locating beams are directed through said surrounding area only during intermittent target locating periods and (ii) such that, during each target locating period, the most recently obtained location data from said locating beams is used during that period to compare the location data with the reference data and determine the position of the target with respect to the locations of the reference points;

(g) fifth means operable within each target locating period and responsive to the position of the target region determined by said third means within that period for insuring that said radiosurgical beam is accurately directed into said region;

wherein said first means includes means for moving said radiosurgical beam along a predetermined path transverse to said beam path while, at the same time, the radiosurgical beam path is directed into said target region, whereby to cause the radiosurgical beam to pass through different sections of healthy tissue as a result of its transverse movement along said predetermined path;

further comprising means for providing that said transverse path is a non-circular, non-linear path, whereby movement of said radiosurgical beam along said non-circular, non-linear path defines a non-spherical target region;

wherein said means for moving said radiosurgical beam along said non-circular, non-linear transverse path includes a robotic arm which carries said delivery mechanism of said radiation beam generator, said apparatus also including emergency stop means separate from and independent of said first means for automatically stopping all movement of and turning off said radiosurgical beam if said radiosurgical beam deviates from said transverse path of movement;

wherein said emergency stop means includes fixedly moused signal transmitting/receiving means mounted to a fixed surface other than said robotic arm for transmitting and receiving signals, movable signal transmitting/receiving means mounted to said robotic arm having a different position at different times for movement therewith and in signal communication with said fixedly mounted signal transmitting/receiving means, and means for cooperating with said fixedly mounted transmitting/receiving means and for continuously monitoring the position at a given time of said robotic arm and said radiation beam generator delivery mechanism; and

wherein said fixedly mounted signal transmitting/receiving means includes a plurality of first devices, each of which including means for transmitting coded infrared signals and including means for receiving coded ultrasound signals, and wherein said movable signal transmitting/receiving means includes a plurality of second devices, each of which including means for transmitting coded ultrasound signals and including means for receiving coded infrared signals.

2. An apparatus according to claim 1 further comprising means for providing that each of said intermittent treatment periods is immediately followed by at least one of said target locating period.

3. An apparatus according to claim 2 further comprising means for providing that each of said treatment periods is between about 0.5 and 1.0 second in duration and each of said target locating periods is between about 1.0 and 2.0 seconds in duration.

4. An apparatus according to claim 1 further comprising means for providing that said means for moving said radiosurgical beam along said predetermined path does so only during target locating periods.

5. An apparatus according to claim 1 further comprising means for providing that said transverse path is circular or partially circular path having a center with said target region at the center thereof.

6. An apparatus according to claim 1 further comprising means for providing that said traverse path is a particular spiral path along which said radiosurgical beam is moved to define an ellipsoidal target region.

7. An apparatus for carrying out radiosurgery on a particular target region within a patient, said apparatus comprising:

(a) means for generating a radiosurgical beam of radiation;

(b) beam aiming means for supporting said beam generating means in a way which directs said beam along a beam path through the target region;

(c) means for moving said beam aiming means along a predetermined, non-circular and non-linear path transverse to said beam path while, at the same time, said beam path is directed into the target region, whereby directing said radiosurgical beam through said target region at particular treatment points along said non-circular and non-linear path defines a non-spherical target region; and

further including means for generating a computed imaginary sphere having a surface and having a center within said target region and further comprising means for providing that said means for moving the beam aiming means does so in a way which causes the point at which said beam is generated to move along said transverse path which said transverse path at all time remains on said surface of said imaginary sphere.

8. An apparatus according to claim 7 further comprising means for providing that said predetermined particular spiral path along which said radiosurgical beam is moved to define an ellipsoidal target region.

9. An apparatus according to claim 7 including means for providing that said predetermined path is a particular spiral path on the surface of said sphere having a radius defined by the following equations:

space="preserve" listing-type="equation">Z.sub.i =Rcos θ

.sub.i

space="preserve" listing-type="equation">X.sub.i =Rsin θ

.sub.i Cos φ

.sub.i

space="preserve" listing-type="equation">Y.sub.i =Rsin θ

.sub.i Sin φ

.sub.i

where R is a radius of said sphere, X, Y and Z for a three dimensional coordinate system with a origin at the center of the sphere, θ

is an angle defined by the Z axis and the radius R, φ

is a angle defined by the X-axis and the X-Y component of the radius R within in the X-Y plane, and i is a particular treatment point on the spiral path.

10. An apparatus according to claim 9 further including means for moving said beam aiming means intermittently along said spiral path so that said beam is generated at said particular treatment point only when said beam aiming means is stationary.

11. An apparatus according to claim 10 including means for providing that there are a plurality of points i on said spiral path at which said beam is generated is defined by the following equations:

##EQU2## where N equals points in total i at which the beam is generated.

12. An apparatus according to claim 7 including emergency stop means separate from and independent of said beam aiming means for automatically stopping all movement of said beam aiming means and turning off said radiosurgical beam if said beam aiming means deviates from said transverse path.

13. An apparatus according to claim 12 further including a robotic arm wherein said emergency stop means includes fixedly mounted signal transmitting/receiving means mounted to a fixed surface other than said robotic arm for transmitting and receiving signals, movable signal transmitting/receiving means mounted to said robotic arm having a different position at different times for movement therewith and in signal communication with said fixedly mounted signal transmitting/receiving means, and means for cooperating with said fixedly mounted transmitting/receiving means and for continuously monitoring the position at a given time of said robotic arm and said radiosurgical beam generating means.

14. An apparatus according to claim 13 wherein said fixedly mounted signal transmitting/receiving means includes a plurality of first devices, each of which including means for transmitting coded infrared signals and including means for receiving coded ultrasound signals, and wherein said movable signal transmitting/receiving means includes a plurality of second devices, each of which including means for transmitting coded ultrasound signals and including means for receiving coded infrared signals.

15. An apparatus according to claim 7 including means for providing that said means for generating said radiosurgical beam does so in a controlled intermittent manner so as not to direct said beam into certain critical areas of the patient as the beam is moved along said transverse path.

16. An apparatus for carrying out radiosurgery on a particular target region within a patent, said arrangement comprising:

(a) means for generating a radiosurgical beam of radiation;

(b) means including a robotic arm for supporting said beam generating means in a way which directs said beam along a beam path through said target region;

(c) means for moving said robotic arm and therefore said radiosurgical beam along a predetermined path transverse to said beam path while, at the same time, said beam path is directed into said target region; and

(d) emergency stop means separate from and independent of said means including said robotic arm for automatically stopping all movement of said robotic arm and turning off said beam if said robotic arm deviates from said transverse path;

wherein said emergency stop means includes fixedly mounted signal transmitting/receiving means mounted to a fixed surface other than said robotic arm for transmitting and receiving signals, movable signal transmitting/receiving means mounted to said robotic arm having a different position at different times for movement therewith and in signal communication with said fixedly mounted signal transmitting/receiving means, and means for cooperating with said fixedly mounted transmitting/receiving means and for continuously monitoring the position at a given time of said robotic arm and said radiosurgical beam generating means; and

wherein said fixedly mounted signal transmitting/receiving means includes a plurality of first devices, each of which including means for transmitting coded infrared signals and including means for receiving coded ultrasound signals, and wherein said movable signal transmitting/receiving means includes a plurality of second devices, each of which including means for transmitting coded ultrasound signals and including means for receiving coded infrared signals.

17. An apparatus according to claim 16 wherein said plurality of first devices includes three such devices and wherein said plurality of second devices includes a number of such devices sufficient to insure that each of said first devices is always in signal communication with at least three of said plurality of said second devices.

18. A method of carrying out stereotaxic surgery on a particular target region having a position within a patient utilizing previously obtained reference data indicating the position of said target region with respect to its surrounding area which also contains certain nearby reference points, each of which having a location said method comprising:

(a) generating a radiation beam;

(b) generating target locating beams;

(c) intermittently directing a radiosurgical beam of radiation into said target region;

(d) intermittently directing a plurality of target locating beams of radiation into and through the surrounding area containing said target region and reference points so that the target locating means, after passing through the surrounding area, contain location data indicating said locations of said reference points within the surrounding area, thus providing a plurality of target positioning periods;

(e) in response to said intermittently directed target locating beams (i) for obtaining the location data from said target locating beams, (ii) intermittently comparing the location data so obtained with the previously obtained reference data, and (iii) determining from each of the intermittent comparisons the position of the target region with respect to said locations of the reference points as a result of each such comparison;

(f) carrying out steps (c), (d) and (e) in cooperation with one another (i) such that said radiosurgical beam is directed into said target region only during intermittent treatment periods and alternatively therewith, said target locating beams are directed through said surrounding area only during intermittent target locating periods and (ii) such that, during each target locating period, the most recently obtained location data from said locating beams is used during that period to compare the location data with the reference data and determine the position of the target with respect to said location of the reference points; and

(g) during said target locating period and responsive to the most recently determined position of the target region within that period, insuring that said radiosurgical beam is accurately directed into said region.

19. A method according to claim 18 including operating said method according to steps (a) through (f) so that each of said intermittent treatment periods is immediately followed by one of said target positioning periods.

20. A method of carrying out radiosurgery on a particular target region within a patient, said method comprising:

(a) generating a radiosurgical beam of radiation at a point by means of a beam generating device;

(b) supporting said beam generating device in a way which directs said beam along a beam path through said target region;

(c) moving said beam device along a predetermined, non-circular and non-linear path transverse to said beam path while, at the same time, said beam path is directed into said target region, whereby directing said radiosurgical beam through said target region at particular treatment points along said non-circular and non-linear path defines a non-spherical target region; and

further including the step of generating a computed imaginary sphere having a surface and having a center within said target region and providing the step of moving said beam generating device in a way which causes the point at which said beam is generated to move along said transverse path while said transverse path at all times remains on said surface of said imaginary sphere having said center within said target region.

21. A method according to claim 20 further including providing that said predetermined path is a particular spiral path on the surface of said sphere defined by the following equations:

space="preserve" listing-type="equation">Z.sub.i =Rcos θ

.sub.i

space="preserve" listing-type="equation">X.sub.i =Rsin θ

.sub.i Cos φ

.sub.i

space="preserve" listing-type="equation">Y.sub.i =Rsin θ

.sub.i Sin φ

.sub.i

where R is a radius of said sphere, X, Y and Z for a three dimensional coordinate system with a origin at the center of the sphere, θ

is an angle defined by the Z axis and the radius R, φ

is a angle defined by the X-axis and the X-Y component of the radius R within in the X-Y plane, and i is a particular point on the spiral path.

22. A method according to claim 21 further comprising the step of intermittently moving said beam generating device along said spiral path and generating said beam therefrom only when said beam generating device is stationary.

23. A method according to claim 22 further including providing that the points i on said spiral path at which said beam is generated is defined by the following equations:

##EQU3## where N equals points i in total at which the beam is generated.

24. A method according to claim 20 further including providing that said predetermined path is a particular spiral path along which said radiosurgical beam is moved in order to define a target region that is ellipsoid in shape.