I found a personal solution, and it's working very well.
I went to target, and bought six pairs of tube socks.
Rubbermaid, in it's "Blue Ice" product line makes what they call "Ice Blankets".
They are mini gell ice packs that come in a sheet of thirty six.
Blue ice blankets 
I took the sheets, and cut them into ribbons, and put a ribbon in each sock, securing them with a rubber band at the top so they wouldn't slide to the toe of the sock.
The I sewed each pair together at the top, leaving enough opening to pull the ribbons of mini ice packs to launder the socks.
I wear these around my neck, the ice drapes over the coroted artery on either side of my neck, and over my upper chest.
Each one lasts about 45- 90 minutes. I keep them in the freezer and change them when they stop cooling.
I was skeptical of my home made devices at first, but they turned out to be working better than I had possibly hoped.
They work VERY well, keeping me alert and cool (er) through service.
Total cost for six? Around eighteen bucks for all the components.