Marker system and related stereotactic procedure

• US 5,954,647 A
• Filed: 04/26/1996
• Issued: 09/21/1999
• Est. Priority Date: 02/14/1995
• Status: Expired due to Term

• Current Assignee: University of Florida Research Foundation, Incorporated (State University System of Florida)
• Original Assignee: University of Florida Research Foundation, Incorporated (State University System of Florida)
• Inventors: Bova, Frank J., Friedman, William A.
• Primary Examiner(s): Lateef, Marvin M.
• Assistant Examiner(s): SHAW, SHAWNA JEANNINE
• Application Number:
  US08/638,088
• Time in Patent Office: 1,243 Days
• Field of Search: 128/653.1, 128/653.2, 128/653.5, 128/664, 128/665, 128/898, 606/130, 378/62, 378/68, 378/204, 378/205, 378/207, 378/208, 600/1, 600/3, 600/7, 600/407, 600/410, 600/421, 600/473, 600/476, 433/68, 433/73, 433/75, 433/213, 433/29, 433/27
• US Class Current: 600/407
• CPC Class Codes: A61B 2034/2055 Optical tracking systems
• CPC Class Codes: A61B 2034/2072 Reference field transducer attached to an instrument or patient
• CPC Class Codes: A61B 2090/101 for stereotaxic radiosurgery
• CPC Class Codes: A61B 2090/363 Use of fiducial points
• CPC Class Codes: A61B 2090/3945 Active visible markers, e.g. light emitting diodes
• CPC Class Codes: A61B 2090/3983 Reference marker arrangements for use with image guided surgery
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: A61B 6/035 Mechanical aspects of CT
• CPC Class Codes: A61B 6/08 Auxiliary means for directing the radiation beam to a particular spot, e.g. using light beams
• CPC Class Codes: A61B 90/14 Fixators for body parts, e.g. skull clamps; Constructional details of fixators, e.g. pins
• CPC Class Codes: A61B 90/16 Bite blocks
• CPC Class Codes: A61N 2005/1059 using cameras imaging the patient
• CPC Class Codes: A61N 5/1049 for verifying the position of the patient with respect to the radiation beam
• CPC Class Codes: A61N 5/1069 Target adjustment, e.g. moving the patient support

Abstract

Repeat fixation for medical procedures is accomplished using a non-invasive locator, specifically a bite plate. The bite plate has at least three fiducial markers on it. The fiducial markers may be LEDs, radiopaque markers for angiography or computerized tomography (CT) imaging or magnetic resonance markers for magnetic resonance (MR) imaging. By detecting the position of the markers, the position of features within the patient (such as a brain tumor or other intracranial target to which radiation is to be applied) can be determined with great precision. Since the bite plate has been molded to uniquely fit to the patient'"'"'s teeth, it may be removed after an initial imaging of the patient. The bite plate may then be re-attached one or more times to the teeth. An alternate embodiment uses a head ring or head holder such as a head mask system with the LEDs thereon. The head ring is useful for single fraction treatments. A comparison is made between the relative patient position and the position of a medical device and a desired relative positioning. One or more error signals are the result of the comparison and are used for display purposes such that a person may manually null or minimize the errors or as feedback control signals for automatic error correction.

Claims

1. A medical method comprising the steps, not necessarily in order, of:

positioning a patient for a first medical procedure;

attaching a mechanically free locator to the patient, the locator having at least 3 fiducial markers thereon and being in registry with a portion of the patient;

using the fiducial markers a first time to get precise positioning information relative to at least part of the patient;

performing a first medical procedure on the patient;

after the first medical procedure, removing the locator from the patient;

at a later time after the removing of the locator, re-attaching the locator to the patient, the locator again being in registry with the portion of the patient and having an identical orientation relative to the portion of the patient as when the locator was previously attached;

after the re-attaching step, using the fiducial markers a second time to get precise positioning information relative to the at least part of the patient;

after the re-attaching step, performing a second medical procedure on the patient; and

wherein

before performing the second medical procedure, the patient is positioned using a positioner independent of the locator to adjust and secure at least the portion of the patient in a desired position.

2. The medical method of claim 1 wherein the attaching and re-attaching of the locator is non-invasive.

3. The medical method of claim 1, wherein the using of the fiducial markers the first and second times utilizes a sensing subsystem for sensing the positions of the fiducial markers.

4. A system for medical procedures, the system comprising:

a locator attachable to a patient, having at least 3 LEDs thereon, and having a registration portion for registration with a portion of a patient'"'"'s body, the registration portion allowing removal of the locator from the patient and re-attachment to the patient with an identical orientation relative to the portion of the patient as when the locator was previously attached, the locator being mechanically free such that a patient is positionable without applying forces to the locator during patient positioning;

a positioner independent of the locator and operable to adjust and to secure at least the portion of the patient in a desired position; and

a sensing subsystem for sensing the positions of the LEDs when the patient is in the desired position.

5. The system of claim 4 wherein the locator is non-invasive.

6. The system of claim 4 further comprising an imaging subsystem for imaging the patient.

7. A medical method comprising the steps, not necessarily in order, of:

positioning a patient for a first medical procedure;

attaching a locator to a patient, the locator having at least 3 fiducial markers thereon and being in registry with a portion of the patient, the locator being mechanically free such that a patient is positionable without applying forces to the locator during patient positioning;

using fiducial markers a first time to get precise positioning information relative to at least part of the patient;

performing a first medical procedure on the patient;

after the first medical procedure, removing the locator from the patient;

at a later time after the removing, reattaching the locator to the patient, the locator again being in registry with the portion of the patient and having an identical orientation relative to the portion of the patient as when the locator was previously attached;

after the re-attaching step, using fiducial markers a second time to get precise positioning information relative to the at least part of the patient; and

after the re-attaching step, performing a second medical procedure on the patient; and

wherein the locator is a bite plate with an external portion connected thereto, and the fiducial markers are on the external portion, and wherein the attaching includes using a mold of dental impression material to bring the bite plate in registry with teeth of the patient, and wherein the re-attaching uses the mold to bring the bite plate in registry with teeth of the patient with an identical orientation relative to the teeth as when the bite plate was previously attached; and

wherein the second medical procedure is a remedial procedure treating at least one problem precisely localized in the first medical procedure; and

wherein, before performing the second medical procedure, the patient is positioned using a positioner independent of the locator to adjust patient position and to secure at least the portion of the patient in a desired position.

8. The medical method of claim 7 wherein the first medical procedure is an imaging of at least a portion of the patient.

9. The medical method of claim 7 wherein the second medical procedure includes radiotherapy.

10. The medical method of claim 7 wherein both the first and second medical procedures include radiotherapy.

11. A system for medical procedures, the system comprising:

a locator attachable to a patient, having at least 3 fiducial markers thereon, and having a registration portion for registration with a portion of a patient'"'"'s body, the registration portion allowing removal of the locator from the patient and re-attachment to the patient with an identical orientation relative to the portion of the patient as when the locator was previously attached, the locator being mechanically free such that a patient is positionable without applying forces to the locator during patient positioning;

a positioner independent of the locator and operable to adjust and to secure at least the portion of the patient in a desired position; and

wherein the locator is a bite plate with an external portion connected thereto, and the fiducial markers are on the external portion, and the bite plate has a mold to bring the bite plate in registry with teeth of the patient with an identical orientation relative to the teeth as when the bite plate was previously attached.

12. The system of claim 11 further comprising a radiotherapy apparatus for applying radiation treatment to a patient, the positioner and sensing subsystem allowing proper positioning of the patient for applying radiation treatment.

13. A system for medical procedures, the system comprising:

a locator attachable to a patient, having at least 3 fiducial markers thereon;

a medical device means for performing a diagnostic imaging or a therapeutic medical procedure on a patient;

a sensing subsystem for sensing the positions of the fiducial markers when the patient is in a position for performing the medical procedure using the medical device;

a first comparison means for comparing positioning information of the fiducial markers to positioning information indicative of a position of the medical devices, and for supplying information indicative of an actual offset between the position of the fiducial markers and the position of the medical device; and

a second comparison means for comparing the actual offset information with desired offset information and for generating an error signal based thereon.

14. The system of claim 13 wherein the locator has a registration portion for registration with a portion of a patient'"'"'s body, the registration portion allowing removal of the locator from the patient and re-attachment to the patient with an identical orientation relative to the portion of the patient as when the locator was previously attached, the locator being mechanically free such that a patient is positionable without applying forces to the locator during patient positioning;

and wherein the locator is a bite plate with an external portion connected thereto, and the fiducial markers are on the external portion, and the bite plate has a mold to bring the bite plate in registry with teeth of the patient, and the mold is operable to bring the bite plate in registry with teeth of the patient with an identical orientation relative to the teeth as when the bite plate was previously attached.

15. The system of claim 13 wherein the locator is selected from the group consisting of:

a head ring secured to a support and a head holder secured to a support.

16. The system of claim 13 wherein the locator is a head ring and has a member secured thereto, and wherein the three fiducial markers are mounted to the member so as to uniquely define a plane.

17. A method for performing a diagnostic imaging or a therapeutic medical procedure comprising the steps of, not necessarily in order:

attaching a mechanically free locator to a patient, the locator having at least 3 fiducial markers thereon;

placing the patient adjacent a medical device operable for performing said diagnostic imaging or therapeutic medical procedure on a patient;

sensing the positions of the fiducial markers when the patient is in a position for performing the diagnostic imaging or therapeutic medical procedure using the medical device; and

generating error signals indicating differences between actual patient position information relative to the medical device and a desired patient position relative to the medical device.

18. The method of claim 17 further including the step of adjusting the relative positioning of the patient and the medical device to null or minimize the error signals.

19. The method of claim 17, further including the step of:

performing a first medical procedure on the patient.

20. The method of claim 19, further including the steps of:

removing the locator from the patient after performing said first medical procedure;

later reattaching the locator to the patient at an identical position and orientation relative to the patient;

again sensing the fiducial markers and generating error signals dependent on differences between actual patient position information relative to the medical device and a desired patient position relative to the medical device; and

performing a second medical procedure on the patient.