Method and apparatus for catheter phototherapy with dose sensing

• US 6,749,623 B1
• Filed: 06/12/2000
• Issued: 06/15/2004
• Est. Priority Date: 03/31/2000
• Status: Expired due to Term

• Current Assignee: Arye Rosen, Carmen E. Rodriguez, Richard A. Hsi
• Original Assignee: Arye Rosen, Carmen E. Rodriguez, Richard A. Hsi
• Inventors: Rosen, Arye, Rodriguez, Carmen E, Hsi, Richard A
• Primary Examiner(s): Peffley, Michael
• Assistant Examiner(s): VRETTAKOS, PETER J
• Application Number:
  US09/591,947
• Time in Patent Office: 1,464 Days
• Field of Search: 606/7, 606/14-15, 604/96, 604/101, 607/88, 607/89
• US Class Current: 607/88
• CPC Class Codes: A61B 2017/00057 Light
• CPC Class Codes: A61N 5/0601 Apparatus for use inside the body
• CPC Class Codes: A61N 5/062 Photodynamic therapy, i.e. excitation of an agent

Abstract

A photodynamic therapy method administers, to a patient to be treated, a photosensitive medication which fluoresces when illuminated. The fluorescent light is an indication of the instantaneous phototherapy dose. A catheter according to the invention includes a probe or sensor arrangement for generating a signal representing the instantaneous amplitude of the fluorescence or the incident illumination. The signal is integrated to produce a signal representing the total dose of phototherapy. The photodynamic therapy is terminated when the integrated signal indicates a particular value. The catheter in one embodiment includes an array of semiconductor light sources near its distal end, energized from the proximal end. In another embodiment, the light source is external to the patient, and the light is conducted to the distal end of the catheter by one or more optical fibers. The light sensor may be an optical fiber extending from the proximal to the distal end of the catheter, with a probe end which is directive or omnidirectional. In this case, the dose signal is detected by a photodiode exterior to the catheter and the detected signal is integrated to generate a signal indicative of cumulative dose. In another embodiment, the photodiode is located near the distal end of the catheter.

Claims

1. A phototherapy method, said method comprising the steps of:

administering a photosensitive medication to a patient, which medication fluoresces in response to light flux;

applying energy to a proximal end of a catheter, the distal end of which is adjacent tissue of said patient, to thereby cause light flux from a distal end of said catheter, whereby said light flux causes said photosensitive medication to fluoresce; and

generating a signal representative of one of said light flux and said fluorescence; and

coupling said signal by way of said catheter to a location without said patient.

2. A phototherapy method, comprising the steps of:

administering a photosensitive medication to a patient, which medication fluoresces, at a specific wavelength, in response to light flux;

applying light flux to a vas of said patient through a catheter, for thereby performing photodynamic therapy, and causing said medication to fluoresce in response to at least the magnitude of said flux; and

by means of said catheter, routing at least a signal related to said fluorescence to a location without said patient;

determining, from at least said signal, at least one of (a) the intensity of said flux and (b) the duration of said flux.

3. A method according to claim 2, wherein said step of determining from at least said signal includes the step of determining the power of said fluorescence.

4. A method according to claim 2, wherein said step of administering medication includes one of (a) introducing said medication into said vas directly, (b) introducing said medication orally, and (c) introducing said medication by injection through tissue.

5. A method according to claim 4, wherein said step of administering medication includes the step of administering 5-aminolevulinic acid.

7. A method according to claim 4, wherein said step of administering medication includes the step of injection of 5-aminolevulinic acid.

10. A method according to claim 2, wherein said step of applying light flux includes the step of applying electrical excitation to a plurality of semiconductor light sources located at a distal portion of said catheter, which semiconductor light sources produce light in the vicinity of 630 nm.

12. A method according to claim 2, wherein said step of routing at least a signal related to said fluorescence to a location without said patient includes the step of routing a signal related to said flux to a location without said patient.

6. A phototherapy method, said method comprising the steps of:

administering photosensitive 5-aminolevulinic acid medication to a patient, which medication fluoresces at a specific wavelength in response to light flux, said administering being by one of (a) introducing said medication into said vas directly, (b) introducing said medication orally, and (c) introducing said medication by injection through tissue;

applying light flux to a vas of said patient through a catheter, for thereby performing photodynamic therapy, and causing said medication to fluoresce in response to at least the magnitude of said flux; and

by means of said catheter, routing at least a signal related to-said fluorescence to a location without said patient;

determining, from at least said signal, at least the power of said fluorescence;

wherein said step of applying light flux includes the step of applying a light flux having its peak amplitude at a wavelength in the vicinity of 5 (10<sup>−

7</sup>) meters.

8. A method, comprising the steps of:

administering a photosensitive medication to a patient, which medication fluoresces, at a specific wavelength, in response to light flux, said step of administering medication includes one of (a) introducing said medication into said vas directly, (b) introducing said medication orally, and (c) introducing said medication by injection through tissue;

applying light flux to a vas of said patient through a catheter, for thereby performing photodynamic therapy, and causing said medication to fluoresce in response to at least the magnitude of said flux; and

by means of said catheter, routing at least a signal related to said fluorescence to a location without said patient;

determining, from at least said signal, at least one of (a) the intensity of said flux and (b) the duration of said flux;

wherein said step of applying light flux includes the step of;

generating white light; and

passing said white light through an optical bandpass filter having a peak in transmission response.

9. A method according to claim 8, wherein said step of passing said white light includes the step of passing said white light through an optical filter having a peak transmission response in the vicinity of 5 (10⁻

7) meters.

11. A phototherapy method, comprising the steps of:

administering a photosensitive medication to a patient, which medication fluoresces, at a specific wavelength, in response to light flux;

applying light flux to a vas of said patient through a catheter, for thereby performing photodynamic therapy, and causing said medication to fluoresce in response to at least the magnitude of said flux;

by means of said catheter, routing at least a signal related to said fluorescence to a location without said patient;

determining, from at least said signal, at least one of (a) the intensity of said flux and (b) the duration of said flux; and

further comprising, before said step of administering medication, the step of sensing the fluorescence of said vas of said patient in response to a flux of light.

13. A catheter for phototherapy, comprising:

an elongated body defining an axis of elongation, a distal region, and a proximal region, said distal region being adapted for introduction into a vas of a patient;

an elongated array of semiconductor light sources associated with said catheter body near said distal region, said semiconductor light sources and said body near said semiconductor light sources being such that, when said semiconductor light sources are energized, light from said semiconductor light sources can radiate away from said body of said catheter;

electrical energization means extending along at least a portion of the length of said body from said proximal region to said array, for energizing at least some of said semiconductor light sources of said array;

a balloon associated with said distal region of said catheter, said balloon having a membrane, said membrane being at least translucent to the light produced by said semiconductor light sources, whereby light radiated away from said semiconductor body in said distal region can pass through said membrane of said balloon;

a balloon inflation lumen extending from said proximal region of said catheter to said balloon;

whereby inflation of said balloon tends to flatten folds in the wall of said vas, and energization of said semiconductor light sources allows light to reach said wall of said vas, and, in the presence of a photosensitive substance in said wall of said vas, said light reaching said wall of said vas results in fluorescence of said photosensitive substance;

said catheter further comprising;

a fluorescence light pickup and transmission arrangement at least partially located in said distal region, for receiving said fluorescence light, and for carrying a signal responsive to said fluorescence light to said proximal region, and for making said signal responsive to said fluorescence light available at said proximal region of said catheter, wherein said fluorescence light pickup and transmission arrangement comprises a photosensor associated with said distal region of said catheter, for receiving said fluorescence light, and for generating an electrical signal in response to said fluorescence light, and for conducting said electrical signal to said proximal end of said catheter.

14. A catheter for phototherapy, said catheter comprising:

an elongated body defining an axis of elongation, a distal region, and a proximal region, said distal region being adapted for introduction into a vas of a patient;

an elongated array of semiconductor light sources associated with said catheter body near said distal region, said semiconductor light sources and said body near said semiconductor light sources being such that, when said semiconductor light sources are energized, light from said semiconductor light sources can radiate away from said body of said catheter;

electrical energization means extending along at least a portion of the length of said body from said proximal region to said array, for energizing at least some of said semiconductor light sources of said array;

a balloon associated with said distal region of said catheter, said balloon having a membrane, said membrane being at least translucent to the light produced by said semiconductor light sources, whereby light radiated away from said semiconductor body in said distal region can pass through said membrane of said balloon;

a balloon inflation lumen extending from said proximal region of said catheter to said balloon;

whereby inflation of said balloon tends to flatten folds in the wall of said vas, and energization of said semiconductor light sources allows light to reach said wall of said vas, and, in the presence of a photosensitive substance in said wall of said vas, said light reaching said wall of said vas results in fluorescence of said photosensitive substance;

said catheter further comprising;

a fluorescence light pickup and transmission arrangement at least partially located in said distal region, for receiving said fluorescence light, and for carrying a signal responsive to said fluorescence light to said proximal region, and for making said signal responsive to said fluorescence light available at said proximal region of said catheter; and

an optically dispersive structure lying between said fluorescence light pickup and transmission arrangement and an outer surface of said balloon.