Stone sense with fiber erosion protection and camera saturation prevention, and/or absence-detection safety interlock

Abstract

A system and method for detecting relative location of a surgical laser fiber tip relative to a surgical laser target during a surgical laser procedure utilizes a spectrophotometer to detect radiation indicative of the relative location. For example, the detected radiation may indicate contact between the fiber tip and a stone being subjected to laser lithotripsy, so as to prompt the surgeon to withdraw the fiber tip from the stone and/or take other action to limit contact-induced erosion of the fiber tip, and to avoid saturation of the endoscope camera resulting from the flash that occurs following contact. In addition, the absence of any detected radiation by the spectrophotometer may be used to indicate that the stone is no longer present, or that the fiber tip is no longer aimed at the stone, prompting the operator to reposition the fiber and/or temporarily cease firing of the laser. The main surgical laser may be a pulsed Holmium laser, which is delivered to the target through the optical fiber together with a pulsed 532 nm aiming beam.

Claims

1. A system for detecting the absence of a stone during a laser lithotripsy procedure, comprising: a main laser for delivering laser energy having a first wavelength λ1 through an optical fiber; a ferrule or sleeve fitted to an end of the fiber to serve as a standoff that physically prevents contact between an end face of the fiber and the stone; a detector for detecting the energy reflected or emitted by the stone when the laser energy having a first wavelength λ1 is being delivered to the stone, wherein the energy reflected or emitted by the stone includes energy having at least one additional wavelength λ3; and an alarm or safety interlock for (a) generating an alarm, or (b) cutting-off or modulating the main laser, in response to detection of an absence of said additional wavelength λ3.

2. A system as claimed in claim 1, wherein the detector is configured to detect the absence of the stone when the reflected or emitted energy having the wavelength λ3 is below a threshold level.

3. A system as claimed in claim 1, wherein the energy reflected or emitted by the stone passes back through the optical fiber to the detector.

4. A system as claimed in claim 3, further comprising a beam splitter for separating the energy having at least one additional wavelength λ3 from the emitted or reflected energy passing back through the optical fiber.

5. A system as claimed in claim 1, further comprising a secondary light source for delivering light having a second wavelength λ2 through the optical fiber to the stone.

6. A system as claimed in claim 5, wherein the secondary light source is one of a laser, LED, or endoscope light.

7. A system as claimed in claim 5, wherein the secondary light source serves as an aiming beam light source.

8. A system as claimed in claim 7, wherein the secondary light source is a pulsed UV-VIS-IR laser.

9. A system as claimed in claim 1, wherein the main laser is a pulsed laser.

10. A system as claimed in claim 9, wherein the main laser is a pulsed Holmium laser.

11. A system as claimed in claim 9, wherein the laser has an active mode that allows the laser to automatically pulse after detecting radiation reflected or emitted by the stone.

12. A system as claimed in claim 1, wherein the detector is a spectrometer, and the spectrometer is configured to analyze stone or vaporized material composition.

13. A system for detecting the absence of a stone during a laser lithotripsy procedure, comprising: a main laser for delivering laser energy having a first wavelength through an optical fiber; a detector for detecting the energy reflected or emitted by the stone when the laser energy having a first wavelength is being delivered to the stone, wherein the energy reflected or emitted by the stone passes back through the optical fiber to the detector and includes energy having at least one additional wavelength; and an alarm or safety interlock for cutting-off or modulating the main laser, in response to detection of an absence of said additional wavelength.

14. A system as claimed in claim 13, wherein the detector is configured to detect the absence of the stone when the reflected or emitted energy having the additional wavelength is below a threshold level.

15. A system as claimed in claim 13, further comprising a beam splitter for separating the energy having at least one additional wavelength from the emitted or reflected energy passing back through the optical fiber.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic diagram of a contact-sensing system arranged in accordance with the principles of a preferred embodiment of the invention.

(2) FIG. 2 is a timing diagram for the system of FIG. 1.

(3) FIG. 3 is a schematic diagram of a stone detecting safety interlock arranged in accordance with the principles of a second preferred embodiment of the invention.

(4) FIG. 4 is a timing diagram for the system of FIG. 3

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(5) As illustrated in FIG. 1, the system of the invention includes a conventional laser delivery apparatus that includes a laser 1 capable of delivering stone vaporizing or destroying pulses during a laser lithotripsy procedure. The system may also include a secondary light source, which could be a laser or LED light source 2 that serves to provide an aiming beam, but which could also be an endoscope light, etc.

(6) The main laser 1 may, by way of example and not limitation, be a Ho:YAG laser that outputs pulses of wavelength λ1 at a frequency of 10 Hz. In the illustrative example where a secondary light source 2, which may for example be any pulsed UV-VIS-IR laser, is included to provide an aiming beam. By way of example and not limitation, the aiming beam may have a wavelength λ2 of 532 nm (green) that causes the stone to fluoresce at the point of incidence, and that also has a pulse frequency of 10 Hz. The outputs of the of main laser 1 and secondary light source 2 are injected into an optical fiber 4, for delivery through the fiber 5 to the stone 6.

(7) The system illustrated in FIG. 1 also includes a spectrophotometer 3 arranged to detect radiation having a wavelength(s) λ3 that occurs upon and is indicative of contact between the stone 6 and the fiber tip 5. As shown in FIG. 2, laser 1 and secondary light source 2 deliver respective first and second pulses during a lithotripsy procedure in which the fiber tip 5 is normally positioned adjacent to but not in contact with the stone. However, before the third pulse, the fiber tip 5 contacts the stone 6, causing a responsive radiation emission at wavelength(s) λ3, which is detected by the spectrophotometer 3. Alternatively, the secondary light source could come from the endoscope and/or the scope image detection could pick up the radiation of wavelength(s) λ3 that occurs upon contact between the fiber tip 5 and the stone 6.

(8) Detection of a threshold level of radiation at wavelength(s) λ3 can be used to generate an alarm or contact signal that prompts the surgeon to withdraw the fiber tip from the stone, and/or optionally trigger cut-off, cut-on, or modulation of the main laser 1, before significant erosion and a camera-saturating flash occur. After pull-back of the laser tip 5 from the stone 6, the lithotripsy operation can proceed as normal, as indicated by the fourth main and aiming beam pulses illustrated in FIG. 2.

(9) As an additional feature, some tissues like stones re-emit an optical signature composed of multiple wavelengths when illuminated by the light of wavelength λ2, such that the stone composition can be determined with the spectrophotometer 3. As a result, the detected radiation λ3 may be comprised of multiple wavelengths and intensities. This information could be useful for diagnostic purposes or help determine laser output parameters.

(10) Alternatively, the failure to detect radiation at a wavelength indicative that the target is present and being irradiated may be used to trigger a warning that the target is not present, or to trigger an automatic shut off or attenuation of the laser. The wavelength indicative that the target is present may be the same wavelength(s) λ3 used to indicate contact, but at a level lower than the contact threshold, or the wavelength or wavelengths being monitored for their presence could be different from wavelength(s) λ3. Conversely, the laser may also be provided with an active mode that allows the laser to automatically pulse after detecting radiation reflected or emitted by the target when it is in an optimal position.

(11) As shown in FIGS. 3 and 4, if the system disclosed herein is used with a “SoftTip” 7 of the type described in PCT Appl. No. PCT/US2017/31091, then stone contact could be limited to lasing only when the “SoftTip” 7 is in contact with the stone 6. This would limit the effects of retro-repulsion of the stone 6.

(12) In the system of FIG. 3, which may be applied to an optical fiber arrangement with a “SoftTip” that provides a standoff, the spectrophotometer 3 detects a wavelength(s) λ3 resulting from reflection or emission by the stone 6 during application of the main laser wavelength λ1. The reflected or emitted wavelength(s) λ3 may be separated by a beam splitter 9 after traveling back through the optical fiber 4. A main laser controller, represented by decision block 7, receives a signal from the spectrophotometer that indicates whether radiation of wavelength(s) λ3 have been detected and disables the main laser 1 if the signal has not been detected.

(13) As shown in FIG. 4, control of the laser output may be achieved by a shutter or trigger input that only allows a pulse to be injected into the fiber when presence of the stone is indicated by a “high” or equivalent signal output by the spectrophotometer.

(14) By only firing the laser when the fiber tip is in the optimal position for target vaporization, thereby reducing extraneous pulses that cause target retro repulsion and wear on equipment, while optimizing efficiency and reducing overall surgical time.

(15) Finally, according to an additional optional feature of the invention, which may be applied to either embodiment, if laser 1 vaporizes a target, the resulting free floating ions and electrons produce a spectrum that can be used to identify the elemental composition of the vaporized material. The spectrometer 3 can verify this spectrum and monitor its amplitude to determine stone distance from fiber tip.