Week 4

The most interesting thing I saw this week was a lung biopsy with Dr. Yankelevitz. We got to see one in the morning which was done the standard way, during which the needle is guided to a suspicious looking area using CT images in a step wise process. First an image is acquired and the patient is asked to hold their breath while the surgeon moves the needle closer to the target site and the process is repeated several times. In the afternoon we got to see a particularly interesting one. This patient had come in twice already for a biopsy, but each time they missed the spot and didn't get a good sample. The reason for this was that the patient apparently was unable to control her breathing. Dr. Yankelevitz therefore decided to try a third time, but this time using a fluoro CT. This is the same as a CT scan but done continuously (named after the fluorescent screen they used to use for this) and achieves a frame rate of about 6 fps. This procedure is not a preferred option as it involves much higher radiation exposure to the patient and particularly the surgeon (we could actually see his fingers on the images). It was really interesting to see continuous images as the patient is inhaling and exhaling and we were able to watch the heart beat to some extent as well. It also came to show again how important well designed equipment is in the hospital. They rarely do a fluoro CT and so few people knew how to use it. Initially, we could not get the machine to do a continuous image for longer than 30 seconds before it had to process and save all the images it took and reset (~3-5min wait) before the next 30 seconds of images could be taken. This was particularly frustrating as Dr. Yankelevitz was clearly struggling to keep this patient from breathing too much and several times he was close to getting to the spot and then the machine stopped taking images. Finally, a technician was able to get the machine to work for 90 seconds at a time and after the second biopsy the quick stain revealed something and Dr. Yankelevitz believes he managed to get a good sample, but was still not sure though.
In rare cases (especially if the patient isn't good at holding their breath) this procedure can also cause the lungs to collapse afterwards and this happened in this case as well, so they actually had to insert another tube (again using the CT) to deflate the area around the lungs. I think in total the patient and the surgeon had ~5min of continuous x ray exposure and it was obvious why they don't prefer this method.