Dr. Mary Decker talks about the difference between the CyberKnife and other radiation treatments.
Read the full transcript »
What makes the CyberKnife treatments so different from other radiation treatments? Dr. Mary Decker: Now when we do regular radiation, if the patient moves we have to stop the machine, we have to go in, we have to move the patient back into position, take some films if those are good then we restart the treatment. With this machine if the patient moves this small amount, you have detectors and these are X-ray tubes in the ceiling and they are constantly taking X-rays at the fixed 45 degree angle that go into these detectors in the floor that feeds back through the computers back into the machine. If the patient moves a little bit, this feedback will tell the machine you need to move a few millimeters and corrected that motion and the machine will do it. Because this is the phantom that doesn't move, it's not doing it right now. But when we see the live treatments, you see the machine pause, make what looks like a little shrug to one side and then go on again, and that's a huge advantage, because that's what allows you to get those tight margins. The large margins we use in other treatments are to make up for all that patient motion. If you do CAT scans of people as they are lying on a table, it's funny the amount of motion that's going on inside of your body of all your internal organs that we are not aware of. When you breath your kidneys move, who know, we didn't know until we started to do these kind of live action CTs. Your kidneys move, your stomach moves, your bowel moves, everything is always moving. And you think well, why can't you just catch up with that. Well we don't have a way of really being able to measure that motion until we came up with the technology like this. You got to be able to measure that motion and correct for it every -- all along through the treatment. Right now, it's limited how much correction we can make. What we are trying to do in radiation oncologist hit the target, which is the cancer and not hit the surrounding radiation sensitive structures and this is what allows us to do that with extreme precision, we can't get in a couple of millimeters, we can't do that with any other technology other than gamma knife which can only treat the head.