Determining patient-specific vapor treatment and delivery parameters
Methods and systems for determining patient specific treatment parameters for delivering vapor to the lung to treat lung tissue. In some embodiments vapor is delivered to the lung to cause coagulative necrosis, inducing fibrosis and thereby reducing the volume of at least one segment of the lung. The delivery parameters can be adjusted depending on the desired degree of injury to be induced in the lung tissue.
1. A method of applying energy to tissue of a patient's lung to reduce the volume of the lung, the method comprising:
identifying at least one region of lung including the lung tissue to be treated;
inserting a delivery device into the lung region;
delivering vapor through the delivery device to the lung tissue to be treated at a dose between about 5 calories/gram to about 40 calories/gram, wherein the vapor undergoes a phase change to liquid, and energy released during the phase change is transferred to the lung tissue to injure the tissue.
2. The method of claim 1 wherein the region is a lung segment or sub-segment.
3. The method of claim 1 further comprising heating the vapor to at least 100° C. before delivering the vapor.
4. The method of claim 1 wherein the dose delivered causes the lung volume to be reduced over a period of about 4 to about 8 weeks.
5. The method of claim 1 wherein the dose delivered causes the lung volume to be immediately reduced from shrinking and or denaturing of collagen.
6. The method of claim 1 wherein the energy transferred to the tissue causes coagulative necrosis of the lung tissue.
7. The method of claim 6 wherein the coagulative necrosis is followed by fibrosis to effectively reduce the volume of the lung region.
8. The method of claim 6 wherein the energy transferred to the tissue causes substantially no thermal fixation.
9. The method of claim 1 wherein delivering the vapor comprises delivering the vapor at a flow rate of between about 20 calories/second to about 200 calories/second.
10. The method of claim 1 wherein delivering the vapor comprises delivering the vapor for a duration of between about 2 seconds to about 30 seconds.
11. The method of claim 10 wherein delivering the vapor comprises delivering the vapor for a duration between about 4 and about 10 seconds.
12. The method of claim 1 further comprising generating the vapor in a generator disposed outside of the patient.
13. The method of claim 1 wherein delivering comprises exposing the lung tissue to the vapor.
14. The method of claim 1 wherein the dose is between about 5 cal/g and about 20 cal/g.
15. The method of claim 1 wherein the dose is between about 5 cal/g and about 10 cal/g.
16. The method of claim 1 wherein the dose is between about 20 cal/g and about 40 cal/g.
17. The method of claim 1 wherein the delivering step comprises ablating microvasculature in the lung tissue.