Treating a tumor or the like with an electric field
View Patent ↗Cells that are in the late anaphase or telophase stages of cell division are vulnerable to damage by AC electric fields that have specific frequency and field strength characteristics. The selective destruction of rapidly dividing cells can therefore be accomplished by imposing an AC electric field in a target region for extended periods of time. Some of the cells that divide while the field is applied will be damaged, but the cells that do not divide will not be harmed. This selectively damages rapidly dividing cells like tumor cells, but does not harm normal cells that are not dividing. Since the vulnerability of the dividing cells is strongly related to the alignment between the long axis of the dividing cells and the lines of force of the electric field, improved results are obtained when the field is sequentially imposed in different directions.
1. A method of selectively destroying or inhibiting the growth of rapidly dividing cells located within a target region of a patient, comprising the steps of:
imposing an AC electric field in the target region of the patient, wherein the electric field has frequency characteristics that correspond to a vulnerability of the rapidly dividing cells, wherein the electric field is strong enough to damage, during the late anaphase or telophase stages of cell division, a significant portion of the rapidly dividing cells whose long axis is generally aligned with the lines of force of the electric field, and wherein the electric field leaves non-dividing cells located within the target region substantially unchanged,
wherein the electric field is imposed in the target region for one or more intervals of time, and wherein the presence of the electric field in the target region for the one or more intervals of time kills a therapeutically significant portion of the rapidly dividing cells.
2. The method of claim 1 , wherein the electric field is imposed in the target region via insulated electrodes.
3. The method of claim 2 , wherein the electrodes are insulated by a thin dielectric coating that has a very high dielectric constant.
4. The method of claim 3 , wherein a conductive gel is disposed between the dielectric coating of the electrodes and a body surface of the patient.
5. The method of claim 1 , wherein the frequency of the electric field is between about 50 kHz and about 500 kHz.
6. The method of claim 5 , wherein the strength of the electric field in at least a portion of the target region is between about 0.1 V/cm and about 10 V/cm.
7. The method of claim 1 , wherein the frequency of the electric field is between about 100 kHz and about 300 kHz.
8. The method of claim 7 , wherein the strength of the electric field in at least a portion of the target region is between about 1 V/cm and about 5 V/cm.
9. The method of claim 1 , wherein the electric field is imposed in the target region intermittently.
10. The method of claim 1 , wherein the electric field is imposed in the target region with a duty cycle of between about 20% and about 50%.
11. The method of claim 10 , wherein the on time of the intermittently imposed electric field is about one second.
12. The method of claim 1 , wherein the electric field is sequentially imposed in the target region in at least two significantly different directions.
13. The method of claim 12 , wherein the frequency of the electric field is between about 100 kHz and about 300 kHz and wherein the strength of the electric field in at least a portion of the target region is between about 1 V/cm and about 5 V/cm.
14. The method of claim 1 , wherein the one or more intervals of time collectively comprise at least six days.
15. A method of selectively destroying or inhibiting the growth of rapidly dividing cells located within a target region of a patient, comprising the steps of:
imposing an AC electric field in the target region of the patient, wherein the electric field has frequency and field strength characteristics that cause the electric field to selectively damage cells that are undergoing cell division, and wherein the electric field leaves cells that are not undergoing cell division substantially unharmed, and
wherein the electric field is imposed in the target region for one or more intervals of time that are collectively sufficient to cause a therapeutically significant portion of the cells that divide in the target region to die.
16. The method of claim 15 , wherein the electric field is imposed in the target region via insulated electrodes.
17. The method of claim 16 , wherein the electrodes are insulated by a thin dielectric coating that has a very high dielectric constant.
18. The method of claim 17 , wherein a conductive gel is disposed between the dielectric coating of the electrodes and a body surface of the patient.
19. The method of claim 15 , wherein the frequency of the electric field is between about 50 kHz and about 500 kHz.
20. The method of claim 19 , wherein the strength of the electric field in at least a portion of the target region is between about 0.1 V/cm and about 10 V/cm.
21. The method of claim 15 , wherein the frequency of the electric field is between about 100 kHz and about 300 kHz.
22. The method of claim 21 , wherein the strength of the electric field in at least a portion of the target region is between about 1 V/cm and about 5 V/cm.
23. The method of claim 15 , wherein the electric field is imposed in the target region intermittently.
24. The method of claim 15 , wherein the electric field is imposed in the target region with a duty cycle of between about 20% and about 50%.
25. The method of claim 24 , wherein the on time of the electric field is about one second.
26. The method of claim 15 , wherein the electric field is sequentially imposed in the target region in at least two significantly different directions.
27. The method of claim 26 , wherein the frequency of the electric field is between about 100 kHz and about 300 kHz and wherein the strength of the electric field in at least a portion of the target region is between about 1 V/cm and about 5 V/cm.
28. The method of claim 15 , wherein the one or more intervals of time collectively comprise at least six days.
29. An apparatus for selectively destroying or inhibiting the growth of rapidly dividing cells located within a target region of a patient, the apparatus comprising:
an AC voltage source; and
a plurality of insulated electrodes that are operatively connected to the AC voltage source, wherein each of the electrodes has a surface configured for placing against the patient's body;
wherein the AC voltage source and the electrodes are configured so that, when the electrodes are placed against the patient's body, an AC electric field is imposed in the target region of the patient, the electric field having frequency characteristics that correspond to a vulnerability of the rapidly dividing cells, wherein the electric field is strong enough to damage, during the late anaphase or telophase stages of cell division, a significant portion of the rapidly dividing cells whose long axis is generally aligned with the lines of force of the electric field, and wherein the electric field leaves non-dividing cells located within the target region substantially unchanged.
30. The apparatus of claim 29 , wherein the surfaces of the electrodes are insulated from the AC voltage source by a thin dielectric coating that has a very high dielectric constant.
31. The apparatus of claim 29 , wherein the frequency of the electric field is between about 50 kHz and about 500 kHz.
32. The apparatus of claim 31 , wherein the strength of the electric field in at least a portion of the target region is between about 0.1 V/cm and about 10 V/cm.
33. The apparatus of claim 29 , wherein the frequency of the electric field is between about 100 kHz and about 300 kHz.
34. The apparatus of claim 33 , wherein the strength of the electric field in at least a portion of the target region is between about 1 V/cm and about 5 V/cm.
35. The apparatus of claim 29 , wherein the electric field is imposed with a duty cycle of between about 20% and about 50%.
36. An apparatus for selectively destroying or inhibiting the growth of rapidly dividing cells located within a target region of a patient, the apparatus comprising:
an AC voltage source; and
a plurality of insulated electrodes that are operatively connected to the AC voltage source, wherein each of the electrodes has a surface configured for placing against the patient's body;
wherein the AC voltage source and the electrodes are configured so that, when the electrodes are placed against the patient's body, an AC electric field is imposed in the target region of the patient, the electric field having frequency and field strength characteristics that cause the electric field to (a) selectively damage cells that are undergoing cell division and (b) leave cells that are not undergoing cell division substantially unharmed.
37. The apparatus of claim 36 , wherein the surfaces of the electrodes are insulated from the AC voltage source by a thin dielectric coating that has a very high dielectric constant.
38. The apparatus of claim 36 , wherein the frequency of the electric field is between about 50 kHz and about 500 kHz.
39. The apparatus of claim 38 , wherein the strength of the electric field in at least a portion of the target region is between about 0.1 V/cm and about 10 V/cm.
40. The apparatus of claim 36 , wherein the frequency of the electric field is between about 100 kHz and about 300 kHz.
41. The apparatus of claim 40 , wherein the strength of the electric field in at least a portion of the target region is between about 1 V/cm and about 5 V/cm.
42. The apparatus of claim 36 , wherein the electric field is imposed with a duty cycle of between about 20% and about 50%.