WO2001074264A1

WO2001074264A1 - Stereo tactic laser/maser energy deposition method and apparatus

Info

Publication number: WO2001074264A1
Application number: PCT/US2001/010326
Authority: WO
Inventors: Louis G. Cornacchia, Iii
Original assignee: Cornacchia Louis G Iii
Priority date: 2000-03-30
Filing date: 2001-03-29
Publication date: 2001-10-11
Also published as: AU2001251153A1

Abstract

An apparatus (5) and method for modifying tissue at the intersection of focused radiant energy beams in which the radiant energy beams (12) include laser (10), maser, and other beams which properly modify the tissue.

Description

STEREO TACTIC LASER MASER ENERGY DEPOSITION METHOD AND APPARATUS

Related Applications This application is a continuation-in-part of U.S. Provisional Application Serial No.

60/193,281 filed March 20, 2000 entitled "Stereotactic Laser Ablation Method And Apparatus".

Field of Invention This invention relates to methods and apparatuses for non-invasively and stereotactically depositing energy to human and animal tissues for the purposes of 1) ablating or modifying the tissue, 2) obstructing blood vessels and 3) obliterating aneurysms with and without the introduction of pharmaceutical agents to facilitate these actions.

Description of the Related Art

Tumors, cysts, and lesions of any organ can pose a health hazard to tire patient, however, brain tumors are particularly troublesome. Often, if the tumor is deep within the tissue of the brain, it is difficult to operate on the tumor to remove it without damaging the organ. Other procedures may be used to destroy the tumor, such as radiation or chemotherapy. The drawbacks to these methods center around damage to the surrounding tissues. For example, radiation therapy has a tendency to damage surrounding tissue and induce neoplasia and chemotherapy assaults the patient in a systemic fashion.

Another recent method employed to destroy rumors and the like includes the use of laser/masers focused beams of colluminated light. Laser/masers (herein used to mean a laser beam or a maser beam or a combination of laser and maser beams) have the advantage over conventional surgical implements in that laser/masers cauterize wounds as they form; there is far less blood loss from laser/maser surgery, to the extent that laser/maser surgery is typically (although not necessarily accurately) called "bloodless surgery." However, laser/maser surgery is heretofore only performed on exposed tissues; a tumor must be either on the surface of an organ or exposed via conventional surgery before a typical laser/maser procedure may be performed. It is known to use visible and near infrared light to determine oxygen levels in blood. Chiefly, visible light oximeters are clipped onto the patient's finger. Light is beamed through the finger onto a sensor. The finger and blood within act as a light filter and allow only certain frequencies of light to pass through. The specific f equencies allowed to impinge on the sensor can vary depending upon the amount of oxygen in the blood. In this way, the blood oxygen level can be determined based on which frequencies of light are detected by the sensor. It is also known to use near infrared light to monitor cerebral blood oxygenation, particularly in infants. However, none of the conventional uses of visible and near infrared light have been useful in actually treating tissue. More specifically, the relative transparency of biological tissue to specific frequency ranges of non-ionizing electromagnetic energy (for example, near infrared 750 nm to 1100 nm) has not yet been exploited to stereotactically and non-invasively deposit energy to deep tissue targets for the purposes of treating disease by means of multiple laser/maser sources all targeting the same point.

Summary of the Invention Accordingly, it is an object of the invention to provide a system and method for treating tumors, vascular malformations, cerebral aneurysms, and functional brain disorders.

It is another object to the invention to provide a system and method for treating tumors that are not on the surface of an organ in a non-invasive manner.

It is another object to the invention to provide a system and method for treating tumors in a non-invasive manner that does not harm the surrounding tissue.

It is another object to the invention to provide a system and method for modifying portions of tissue that are not on the surface of an organ in a non-invasive manner.

It is another object of the invention to provide a system and method for augmenting penetration depth of laser/masers in tissue while minimizing beam dispersion. The above and other objects are fulfilled by the invention which is a system for ablating and/or modifying tissue via laser/masers. One or more laser/masers are provided and can be adjusted in several different manners. The wavelength of the beam can be altered for the purpose of adjusting the efficacy of the laser/maser on different types of tissues. Similarly, the waveform of the beam can be varied. Multiple laser/masers can be used to converge on a single point of tissue. Preferably, the laser/masers are in the infrared or near-infrared range of the spectrum or other frequency ranges with high transmissivity through biological tissues. Near infrared light can pass through the skin and cranium and can act upon certain selected portions of internal tissue. For procedures treating a person's brain tissue, the laser/masers are especially efficacious when beamed through either the temple region or the orbital cavity; the cranium is thinnest at these locations, and thus beam dispersal is kept to a minimum. The use of multiple laser/masers enables greater accuracy while reducing the trauma to surrounding tissue. The laser/masers may be fixed or may be mounted on robotic arms controlled via a central processor. The device may preferably incorporate a scanning mode/system in which the tissues of the organ to be treated are imaged prior to, during, and following tissue modification, using one or multiple combinations of wavelengths chosen to tailor the treatment to the nature of the tissue being treated. Alternatively, the laser treatment system would be connected by stereotactic means to imaging data from other modalities such as magnetic resonance imaging, computed tomography imaging, biplane fluoroscope imaging ...etc.

The invention also includes a method of non-invasively treating tissue via application of near-infrared laser/maser light.

Brief Description of the Drawing Figure 1 shows the system according to the invention^

Figure 2 is an alternative embodiment of the invention;

Figure 3 is a perspective view of the laser/maser unit stem mount and control element; Figure 4 is a sectional view through line 4-4 of Fig. 3.

Figure 5 is a partial view of an embodiment in which stem 37 passing through ball 39 and frame 43 articulate to position unit 30; and

Figure 6 is a sectional view through line 6-6 of Fig. 5.

Description of the Preferred Embodiments and Drawing Description will now be given of the preferred embodiment with reference to Figure

1. The inventive system 5 includes more than one all similar to the laser depicted in this figure near infrared laser/masers 10. Laser/masers 10 produce light beams 12 of variable or fixed wavelength, including in the near infrared range at approximately 750 nm to 10 urn. The laser/masers 10 may be fixedly mounted on a wall or patient gantry system or they may be movably mounted on robotic arms 16, for example. Alternatively, clusters of lasers might be arranged in a fixed fashion with each cluster mounted on a robotic arm. Alternatively, each laser, whether mounted individually or clustered, might be mounted on a rotating arm such that its beam of light intersects at a common point at every degree of rotation.

Robotic arm 16 shown in Figure 1 includes a swivel plate 17 attached to a base 18. Swivel plate 17 can be rotated or swiveled in the directions indicated by the arrows on the swivel plate. Servomotors (not shown) disposed in the interior of base 18 control the movement of swivel plate 17. Base 18 may be mounted to a fixed structure, such as a wall, or it may be movably mounted to a support beam 19, for example. Base 18 is preferably movable along the length of beam 19 via any of a number of means, for example, a ball screw, hydraulics, a cable/pulley system, etc. The structure of robot arm 16 is merely illustrative; any convenient mechanical system for manipulating the direction of the baser is contemplated as being within the scope of the invention.

The positions and orientations of laser/masers 10, as well as the position and orientation of bed 30 upon which the patient P is disposed during the procedure, can be controlled by a central processing unit (CPU) 20. The central processing 20 is connected to a 3-dimensional localizing unit 29 placed on the patients head which unit 29 determines the exact geometric relationship between the treatment beam or beams and the patients head including the portion 60 to be treated. The laser/maser beams 12 can be adjusted in wavelength(s), waveform, and/or intensity by a physician or technician utilizing control panel 22 connected to CPU 20. CPU 20 may be programmed to automatically or algorithmically control laser/masers 10. Control panel 22 may employ buttons 21 and/or a joystick controller 23. The system may also include a monitor or touchscreen 24 connected to CPU 20. The monitor can be used when the system is in its imaging mode, as described below.

Changing the wavelength, waveform, and/or intensity of the laser/maser beams 12 can drastically alter the functionality of the system. Different wavelengths of electromagnetic radiation are useful for different applications and affect different types of tissues. In one mode, the laser/masers may be used in synchronization to ablate cancerous cells by applying both beams to the same spot. Each beam individually may not be powered sufficiently to ablate the tumor; thus, the tissue that each beam individually passes through will be unaffected. However, impinging two or more beams onto the same location will cause the tissue at that location to be permanently damaged to the point of non- viability or to be made temporarily non- functional. In procedures other than tumor ablation, lower powered beams may be employed for the purpose of modifying (e.g., heating, cauterizing, coagulating, etc.) a certain portion of tissue without ablating it. The physician or technician can alter the intensity of the beams 12 accordingly. Similarly, beams having slightly different wavelengths, intensities, and waveforms can be used for tissue imaging as well as tissue modification.

The preferred embodiment and use of the system and method involves the ablation of intracranial tumors. In operation, the invention works as follows. Patient P is secured to movable bed 30 so that his head/torso/limb will not move relative to bed 30. The physician adjusts the position of bed 30 via control panel 22 and CPU 20. Coordinates of a portion of the patient's head, either in an x-, y-, z-axis Cartesian system or a polar/spherical system (or any other convenient system), may be displayed on monitor 24. Cameras 13 mounted on laser/masers 10 can act as spotter scopes on the laser/masers; a visible light beam (not shown) may be shone onto the patient's head to indicate visually precisely where the laser/masers will be impinging on the patient's head. Mixing visible wavelengths with the treatment wavelengths might be employed to facilitate this process. The position of the 5 laser/masers can be modified by the physician using the control panel 22.

Turning to Figures 2-6, laser/maser unit 30 is mounted in and manipulated from base unit 31. Unit 31 has wheels 31w which ride on tracks 32, 33. Unit 31 is caused to move up and down by pinion 34 with teeth 34t engaging teeth-receiving rack 35. Pinion 34

10 is driven by motor 36. Laser/maser unit 30 includes laser/maser housing 38 and stem 37 which extend through ball 39 and is attached to ball 39. Ball 39 is mounted for movement in ball socket 41. Laser/maser unit stem 37 has movable cog end 37e positioned in rotatable sweep hand 43 which sweep hand 43 travels in orbit (O). (See Figure 3). Cog end

15 37e moves in and out of frame 43 when rotated by motor 45. Frame 37 includes racks with interior teeth 40a, 40b. Frame 37 rotates about axle 46 when motor 48 is activated.

When cog end 37e moves to selected locations in the area of orbit O, laser/maser 20 unit 30 moves in a conical volume which volume includes a circular area whose size may be varied by selecting the size of orbit O and lengths di and d₂.

Turning back to Figure 2, bed 50 supporting patient (P) is movable along 5 longitudinal tracks 51, 52 and cross tracks 53, 54. Also shown are laser/maser beam VBi and visible light beam VB₂ from camera 30 which beams VB are usable for spotting.

A second laser/maser unit (not shown) of similar construction and operation is mounted spaced from unit 30 which second unit provides a second light beam NB which 0 intersects with beam VBi in the portion 60 to be treated of patient P.

In operation, the system is utilized as follows: First, the patient is placed on bed 30, 50 preferably in a manner to prevent him from moving his head relative to the bed. Laser/masers 10 are preferably activated in the imaging mode by a physician operating the 5 device from control panel 22. Stereotactic techniques, including the use of fiducials, would be employed to target energy to regions identified by other imaging means including MRI and CAT scanning. The beams 12 may be shaped in any convenient geometry for tissue scanning, be it a point, a line, or an area. The beams 12 are composed of light preferably in the infrared or near infrared region of the e-m spectrum. The beams 12 can pass through the cranium with a minimal amount of dispersion. Detectors interpret the scan of the brain by the laser/maser beams 12. The detectors are placed on the side of the patient's head opposite from the laser/masers and are connected to CPU 20, and the image of the brain they discern is displayed on monitor 24. In the next step, tissue inside the cranium may be ablated or modified. The detectors may also be employed to calibrate the laser/masers to determine the proper beam intensity and/or wavelength required to image and modify the person's brain or other organs. Laser motion (eg., rotation at a fixed radiation with a common point of intersection at all angles) might be employed to maximize energy deposition to the target and minimize deposition to the non-targeted tissues.

The wavelength, intensity, and waveform of the beams 12 is adjusted to be appropriate for modification or ablation while laser or maser beams are preferred, any radiant energy focused-beam which, when intensified by intersection of one or more beams, modifies tissue is within the scope of this invention. Non-ion beams are useful in the practice of this invention. Frequency ranges of non-ionizing electromagnetic radiant energy preferred are those ranges having relative transparency to biological tissue such as 750 nm to 1100 nm. The wave length of gamma radiation is not effective for most applications. CPU 20 can be preprogrammed with the information concerning which wavelength, intensity, waveform is appropriate for which application, or a physician can make these adjustments manually. Laser/masers 10 are aimed via the control panel 22 manipulating robot arm or arms 16. It is preferred to shine the beams 12 through the temple of the skull or through the orbital cavity to minimize the amount of beam dispersion. Multiple beams, from multiple laser/masers, may be trained on the same spot in the brain for a cumulative effect. The wavelength, intensity, and waveform of the laser/masers can be continuously varied between those parameters suitable for imaging and those suitable for ablation/modification to enable the physician to monitor the progress of the ablation/modification procedure. The same laser/masers can be used to generate beams for all three types of procedures, or different laser/masers may be employed for each procedure. The invention is not limited to the above description. For example, the above description primarily focuses on ablating a brain tumor. However, the inventive system and method may be used on any organ of the body and may be used not merely for tumor eradication but for other tissue modification processes such as cauterizing, heating, polymerizing intravenous pharmaceutical agents ...etc. Also, the invention preferably uses infrared and more preferably uses near infrared light, however it is also contemplated that laser/masers in the ultraviolet and other wavelengths range may be employed as well. Further, the invention may be used with intravascular agents injected into the patient for the purposes of improving imaging and/or improving tissue eradification by improving the energy absorptivity of the targeted tissue or altering the effects on the targeted tissue. The range of movement of the laser/maser emitting units and the patient located on the bed in all axes is such that the system is able to accomplish laser/maser beam intersection in any portion of the patient' s body. The movement of such units and the patient is coordinated by the computer and the motors it controls together with the input of the operator.

Claims

I CLAIM:

1. A method of treating a portion of a patient comprising

1) positioning the portion of the patient to be treated at a selected location;

2) providing a first source of laser or maser radiation at a location distant from such portion of the patient which source is movable to vary the direction of the beam radiation;

3) providing a second source of laser or maser beam radiation at a location distant from such portion of the patient which source is also movable; and

4) providing a system of coordinating and controlling the first and second sources to focus such beams at a selected location in such portion of the patient to be treated.

2. The method of claim 1 in which laser or maser emitting units are mounted on movable mounts and the mounts are moved to direct laser/maser beams at the portion of the patient to be treated.

3. The method of claim 1 in which the laser/maser units and patient are moved to create an intersection of laser/maser beams in the portion of the patient to be treated.

4. The method of claim 1 in which the laser or maser radiation is in a range of the electromagnetic spectrum with high transmissivity through biological tissue.

5. The method of claim 1 in which the laser or maser is in the infrared or near- infrared range.

6. A method of treating a portion of a patient comprising 1) positioning the portion of the patient to be treated at a selected location;

2) providing a first source of focused-beam radiation which radiation when intensified by intersection with one or more focused-beam radiation, modifies tissue at a location distant from such portion of the patient which source is movable to vary the direction of the beam radiation;

3) providing a second source of laser/maser beam radiation at a location distant from such portion of the patient which source is also movable; and

7. An apparatus for treating a portion of a patient comprising

1) means for positioning the patient to be treated at a selected location;

2) means for producing a first source of laser/maser radiation at a location distant from such portion of the patient which source is movable to vary the direction of the beam radiation;

3) means for producing a second source of laser/maser beam radiation at a location distant from such portion of the patient which source is also movable; and ) a computer controlled system of coordinating and controlling the first and second sources to focus such beams at a location in such portion to be treated.