what is Difference between Diffuse Optical Tomography and Optical Tomography?

What is the difference between transmission and emission tomography?

• Answer:

  the transmission of radiation/energy refers to the fraction of incident radiation that is absorbed by and passes through a substance or body +++ whereas emission refers to the amount of thermal radiation released or given off by a substance. for a substance to emit energy it does not necessarily need to have absorbed from another source, it may as well be its own internal energy.for instance i myself emit energy to the surroundings all the time, thus im able to set off the PIR detectors inside the special light bulbs my mum installed outside the house. however, a body or substance can only be said to transmit energy if the energy has come from another source, been absorbed by the substance and allowed to pass through it. so its basically the fraction of the absobed energy that leaves the body without being captured. hope this helps