Thanks Megaspaz!) Like the left turn this is another hand signal that you should know if you have your license. Unlike the left hand turn this one is a little more tricky to figure out if you aren't familiar with it so don't expect your average car driver to know what this means.
A Single Photon Emission Computed Tomography (SPECT) scan is a type of nuclear imaging test that shows how blood flows to tissues and organs. A SPECT scan integrates two technologies to view your body: computed tomography (CT) and a radioactive material (tracer). The tracer is what allows doctors to see how blood flows to tissues and organs.
SPECT imaging is performed by using a gamma camera to acquire multiple 2-D images (also called projections), from multiple angles. A computer is then used to apply a tomographic reconstruction algorithm to the multiple projections, yielding a 3-D data set.