Michelle Bradbury – Radiologist
Hi everyone! I’m going to give you a quick run of what we are doing in the operating room, with a small particle that we have developed with Cornell University. Here it is. It’s a silica particle. And you might say: “What are you using a nanoparticle for?”
Most surgeons are in the operating room, they are looking at disease and they can’t really see the full extended disease. They can’t see lymph nodes, unless it’s abnormal. So, what we are trying to do is introduce something that glows; when you shine light on it, you see it. This is a brand new concept in the operating room to be able to look at it, see it glow, target the disease you want to take out and a whole area of surgery would be changed by doing that.
As you can see, it’s a silica particle that has in the center: the red represents the dye molecules. You shine light on it, it glows for the surgeon. The surgeon sees exactly where these particles are. On the surface of this silica particle which is represented by blue, the particle is coated so that the body doesn’t recognize it. You put some targeting peptides, let’s say, some small molecules that bind to the receptors of tumors and you inject and see where it binds.
And here we are in a patient, we are injecting the patient with the nanoparticle. This particle in this case has been radiolabeled and you take PET images. You want to understand where the particle goes in the body. To do this, we put this radiolabel on the surface. These are PET images taken over three days. In the beginning, you can see the whole body lights up, but then, over the course of time, the particle leaves the body. It’s so small, it’s about a thousand times smaller than the width of a human hair. It leaves the body through the bladder which is in red.
In this same patient, as a matter of fact, the particle went to the tumor site in the pituitary gland. These are MRI images and you can see that there’s a red spot in the center of the image that is a lesion or a tumor in the pituitary gland and the particle binds there. While the particle is there, it’s also clearing out of the body at the same time. This study that we did showed that particle was safe and it also bound to a tumor in the pituitary gland.
We then wanted to focus on the optical properties of the particle, but just before we did that, we are using these melanoma mini swine. They are pigs that are born with melanoma, and we are taking these pigs into the operating room, and we are using the optical properties of the particle, which I’ll show you in a moment, but before we did that, we injected the particle that has the radiolabel on it to map disease.
What we see, before we even use the particles is, when we just take what we use in the clinic, which is a radiolabeled sugar, it’s called “FDG”, it’s radiolabeled, we use it to determine where tumor is in patients. You can see in this pig that there’s a lot of green which is where the labeled particle is, but it’s in the bone, that’s all bone. When we then inject the particle two days later, you see a lot of red areas that are lymph nodes. Those are actually metastatic tumor sites that the particle in red has bound to.
The pig then goes to the operating room. There’s a camera system, it looks like an ultrasound machine. You’re holding the camera, and you’re looking at the nodes in the pig. You open up the pig at the site of a node, which you actually can see here in green, the particle flow is green, and it flows to a black node and it stays in that node. And the surgeon sees the node, and takes the node out. So, many nodes can be identified by this technique.