High pressure neon arc lamp

• US 6,593,706 B1
• Filed: 10/02/2001
• Issued: 07/15/2003
• Est. Priority Date: 10/02/2001
• Status: Expired due to Fees

• Current Assignee: Los Alamos National Security LLC (Government of the United States of America)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Bigio, Irving J., Sze, Robert C.
• Primary Examiner(s): Wong, Don
• Assistant Examiner(s): Alemu, Ephrem
• Application Number:
  US09/968,829
• Time in Patent Office: 651 Days
• Field of Search: 315/246, 315/348, 315/56, 315/58, 315/59, 315/224, 315/219, 313/567, 313/568, 313/570, 313/572, 313/634, 607/88-95, 604/20
• US Class Current: 315/246
• CPC Class Codes: A61N 5/062 Photodynamic therapy, i.e. excitation of an agent
• CPC Class Codes: H01J 61/16 having helium, argon, neon, krypton, or xenon as the principle constituent
• CPC Class Codes: H01J 61/82 Lamps with high-pressure unconstricted discharge having a cold pressure > 400 Torr

Abstract

A high pressure neon arc lamp and method of using the same for photodynamic therapies is provided. The high pressure neon arc lamp includes a housing that encloses a quantity of neon gas pressurized to about 500 Torr to about 22,000 Torr. At each end of the housing the lamp is connected by electrodes and wires to a pulse generator. The pulse generator generates an initial pulse voltage to breakdown the impedance of the neon gas. Then the pulse generator delivers a current through the neon gas to create an electrical arc that emits light having wavelengths from about 620 nanometers to about 645 nanometers. A method for activating a photosensitizer is provided. Initially, a photosensitizer is administered to a patient and allowed time to be absorbed into target cells. Then the high pressure neon arc lamp is used to illuminate the target cells with red light having wavelengths from about 620 nanometers to about 645 nanometers. The red light activates the photosensitizers to start a chain reaction that may involve oxygen free radicals to destroy the target cells. In this manner, a high pressure neon arc lamp that is inexpensive and efficiently generates red light useful in photodynamic therapy is provided.

Claims

1. A neon arc lamp comprising:

a translucent housing having a substantially cylindrical bore wherein the ratio of the diameter of the bore to the length of the bore is in the range from about 1;

10 to about 1;

30; and

a quantity of substantially pure neon gas contained within the bore and having a pressure of about 500 Torr to about 22,000 Torr.

2. The neon arc lamp of claim 1, wherein the diameter of the bore is about 4 millimeters to about 6 millimeters.

3. The neon arc lamp of claim 2, wherein the length of the bore is between about 4 centimeters and about 12 centimeters.

4. The neon arc lamp of claim 1, further comprising a first electrode secured at one end of the bore and a second electrode secured at an opposite end of the bore.

5. The neon arc lamp of claim 4, wherein the first electrode is a cathode and the second electrode is an anode.

6. The neon arc lamp of claim 4, further comprising a pulse generator configured to apply a voltage between the first electrode and the second electrode to cause an electrical arc between the first electrode and the second electrode.

7. The neon arc lamp of claim 6, wherein the voltage is in the range of about 24 kilovolts to 30 kilovolts.

8. The neon arc lamp of claim 6, wherein the pulse generator is configured to produce a pulse of voltage at a rate of about 1 to 100 Hertz.

9. The neon arc lamp of claim 6, wherein the electrical arc produces incoherent light having wavelengths between about 625 nanometers and about 645 nanometers.

10. The neon arc lamp of claim 6, further comprising a helical corona wire wrapped around the housing, attached to the first electrode, and extending from the first electrode.

11. The neon arc lamp of claim 10, wherein the helical corona wire creates a corona discharge in the quantity of neon gas to lower impedance between the first electrode and the second electrode to allow current in the range from about 100 amperes to about 200 amperes to pass between the first electrode and the second electrode.

12. A photosensitive drug activation device comprising:

a high pressure neon arc lamp configured to generate light having wavelengths between about 625 nanometers and about 645 nanometers, wherein neon gas within the high pressure neon arc lamp has a pressure in the range from about 500 Torr to about 22,000 Torr; and

a pulse generator configured to pass voltage through the high pressure neon arc lamp in the range from about 24 kilovolts to about 30 kilovolts.

13. The photosensitive drug activation device of claim 12, wherein the high pressure neon arc lamp is further configured to produce an average power of 0.169 watts at a pulse rate of about 1 Hertz within the wavelengths.

14. The photosensitive drug activation device of claim 13, wherein the pulse generator generates a voltage pulse at a rate of between about 1 Hertz to about 100 Hertz.

15. The photosensitive drug activation device of claim 14, wherein current of between about 100 amperes and about 200 amperes passes through the high pressure neon arc lamp.

16. A method for activating photosensitizers using incoherent light having wavelengths from about 625 nanometers to about 645 nanometers, the method comprising:

administering a photosensitizer to a patient;

allowing the photosensitizer to be absorbed by target tissue of the patient; and

illuminating the target tissue using a high pressure neon arc lamp comprising substantially pure neon having a pressure in the range of about 500 Torr to about 22,000 Torr to initiate generation of an oxygen free radical to destroy the target tissue.

17. The method of claim 16, wherein the high pressure neon arc lamp comprises a translucent housing having a substantially cylindrical bore wherein the ratio of the diameter of the bore to the length of the bore is in the range of from about 1:

10 to about 1;

30.

18. The method of claim 16, wherein the target tissue is cancerous cells.

19. The method of claim 16, wherein the target tissue is hair follicle cells.