How to locate the DLPFC using the Beam method
The location of the hat is very important, especially at the first stimulation when we’re locating the different structures. So in the future, we’re going to want the hat to be exactly in the same position it is now and to make sure that it is, we take the front and the back, and we very precisely line it up so it is right down the middle, and we want to make sure that there’s about a centimeter above the eyebrows and a little bit more than that above the preauricular point. When we measure for the Beam protocol, we begin with tragus to tragus (this little flap in front of the ear). The spot is also called the preauricular point. We go from tragus to tragus and that is 36. Nasion to inion: the nasion is the farthest deep indentation of the nose bridge there and then right behind the little bump, is 38. And then the circumference, which is best measured around the back so you don’t flap the things in the person’s face, is 60 centimeters. Then we take these three numbers, we feed them into the software and we get the output, and the two numbers that we’ve been given are 6.95.
Now what that means is, start right here (front of hat) and you go 6.95, which is essentially 7, mark a little dot right there, not on him, only on the cap. Then, we know that the nasion to inion is 38, so the vertex will be found at 19 centimeters. We mark the vertex. Then we take the zero point of the tape measure and we aim the tape measure towards this point (the first number). Make sure that the zero is on that first point (vertex) and then we use the second number to determine how far along this line to mark. So the first number to the left, the second number along that line goes to here but not all the way. Now, if you’re going to do the right DLPFC, you’d do the same thing, except the first number you would go to the right. An alternative way is to turn the cap inside out.
When we place the coil over the DLPFC, being sure that it’s a 45-degree angle and being sure that the center point is touching the head and the sides are equal, you take a pen and we use it to mark the location of the coil. We do this very carefully because this location will be used for future stimulations so that when the technician comes, they can simply place the coil there, make sure that it’s lined and it’ll be in exactly the place that the clinician put it at the first treatment.